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ARNAB: Transparent Service Continuity Across Orchestrated Edge Networks | A fast handoff algorithm using intelligent channel scan for IEEE 802.11 WLANs | Lack of consensus on corneal abrasion management: results of a national survey | eng_Latn | 23,500 |
Modified Backoff Algorithm considering Priority in IEEE 802.11 | Adaptive EDCF: enhanced service differentiation for IEEE 802.11 wireless ad-hoc networks | Adipose Lipolysis Unchanged by Preexercise Carbohydrate Regardless of Glycemic Index | eng_Latn | 23,501 |
A survey on secure multipath routing protocols in WSNs | A framework for trust-based cluster head election in wireless sensor networks | Path collective variables without paths | eng_Latn | 23,502 |
Sensor-based architecture for QoS provisioning and fast handoff management in WLANs | A fast handoff algorithm using intelligent channel scan for IEEE 802.11 WLANs | Sensorless vector and direct torque control | eng_Latn | 23,503 |
Fault-Tolerant Wireless Sensor Networks using Evolutionary Games | A biologically inspired networking model for wireless sensor networks | A Systematic Survey on Sensor Failure Detection and Fault-Tolerance in Ambient Assisted Living | kor_Hang | 23,504 |
Cooperative Approaches to Construction and Maintenance of Networks’ Virtual Backbones for Extreme Wireless Sensor Applications | Design and Evaluation of Algorithms for Energy Efficient and Complete Determination of Critical Nodes for Wireless Sensor Network Reliability | Path collective variables without paths | eng_Latn | 23,505 |
On the Security of Wireless Sensor Networks | Analysis of Packets Abnormalities in Wireless Sensor Network | Introduction and Overview of Wireless Sensor Networks | eng_Latn | 23,506 |
Controlling the degradation of Wireless Sensor Networks | An Application-Aware Clustering Protocol for Wireless Sensor Networks to Provide QoS Management | Sensorless vector and direct torque control | eng_Latn | 23,507 |
Development of New Temperature Sensing Cable and Wireless Data Acquisition System | ZigBee Wireless Sensor Network in Industrial Applications | Completely Stale Transmitter Channel State Information is Still Very Useful | eng_Latn | 23,508 |
Mean Territorial Energy Based Clustering Protocol for Randomly Deployed Wireless Sensor Networks | Introduction and Overview of Wireless Sensor Networks | Mutually‐induced traumatic alopecia responsive to husbandry modification in two cohabiting donkeys | eng_Latn | 23,509 |
An Effective Approach to Discern Leaders in Wireless Sensor Networks | Betweenness Centrality in Some Classes of Graphs | Research Issues in Wireless Sensor Network Applications: A Survey | eng_Latn | 23,510 |
Ad-hoc Protocol Performance Analysis Based on Emergency Medical Data | Dynamic source routing in ad hoc wireless networks | Adipose Lipolysis Unchanged by Preexercise Carbohydrate Regardless of Glycemic Index | kor_Hang | 23,511 |
Adaptive dynamic server placement in MANETs | AI Technologies for Tactical Edge Networks ∗ | Performance Improvement of Two Scalable Location Services in MANET | eng_Latn | 23,512 |
DIVVY: An Efficient Shared Cell Scheduling Method and Algorithm for 6TiSCH-Based IoT Networks | Wave: a distributed scheduling algorithm for convergecast in IEEE 802.15.4e TSCH networks | DIGITALIZED SIGNATURES AND PUBLIC-KEY FUNCTIONS AS INTRACTABLE AS FACTORIZATION | eng_Latn | 23,513 |
Context Aware Wireless Sensor Network Suitable for Precision Agriculture | A wireless application of drip irrigation automation supported by soil moisture sensors | Sensorless vector and direct torque control | eng_Latn | 23,514 |
Named-data Emergency Network Services | Information-centric routing for opportunistic wireless networks | Named Data Networking: A survey | eng_Latn | 23,515 |
he absence of network topology knowledge in Opportunistic Network makes information dissemination the most compelling research issue. Communication routes evolve when information is forwarded from source to destination during node interactions. The communications between nodes in Opportunistic Networks are supported through mobility of mobiJe nodes. The connections between mobile nodes are often disconnected. However, information can still be disseminated through the opportunistic connections which are computed dynamically ::: Ideally, in Opportunistic Network when two nodes are in communication range, they should pair-wise identify each other. This process potentially facilitates the formulation of social relationship between those two nodes which later can be used to identify the best possible forwarder to deliver the information. However, formulation of the social relationship between neighbouring nodes and selection of the appropriate node to forward information in Opportunistic Network are not trivial processes. Flooding is the best technique to disseminate the information in Opportunistic Network, because it achieves high delivery ratios, minimize message latency and does not require any pre-existing network infrastructure. However flooding approach suffers from high message overhead due to forwarding the information to all nodes. ::: . Considering the advantage of high delivery ratios of flooding, we proposed and designed the social based Neighbour Selection Protocol (NSP). The NSP uses Frequency in Range (FIR) and Frequency of Interaction (FOI) to assist the selection process. Each selected node in turn uses NSP to select a neighbouring node in order to disseminate information towards the destination. From the experimental results, we found that NSP can reduce the overhead and has delivery ratios close to flooding technique. | In Opportunistic Networks, information ::: forwarding takes place when nodes are in communication range. ::: Absence of knowledge on network topology prior information ::: forwarding poses a compelling challenge in Opportunistic ::: Networks. In these networks, disconnected mobile peers use ::: mobility to opportunistically and dynamically connect to each ::: other in order to disseminate heterogeneous information towards ::: the intended destination. Flooding disseminates information to all ::: nodes in range. Hence, it achieves high delivery performance. ::: However, this form of dissemination congests the network and ::: create considerable amount of network overheads. In this paper, ::: a social-based neighbor selection protocol is proposed to enhance ::: the heterogeneous information dissemination through peer-topeer ::: interaction in Opportunistic Networks. Neighbor is selected ::: based on social structure formulated by Frequency in Range, ::: Frequency of Interaction metrics and Heterogeneity of ::: information. A high valued metric peer from the list of candidate ::: peers is selected as potential forwarder to disseminate ::: information. The delivery performance impact of our protocol on ::: information dissemination was investigated and has been ::: analyzed in customized simulation tool. Experimental results ::: showed that, the proposed neighbor selection protocol achieved ::: delivery performance close to random selection in flooding and ::: reduced 88.25% push overhead incurred during dissemination. | Ensemble streamflow prediction systems produce forecasts in the form of a conditional probability distribution for a continuous forecast variable. A distributions-oriented approach is presented for verification of these probability distribution forecasts. First, a flow threshold is used to transform the ensemble forecast into a probability forecast for a dichotomous event. The event is said to occur if the observed flow is less than or equal to the threshold; the probability forecast is the probability that the event occurs. The distributions-oriented approach, which has been developed for meteorological forecast verification, is then applied to estimate forecast quality measures for a verification dataset. The results are summarized for thresholds chosen to cover the range of possible flow outcomes. To aid in the comparison for different thresholds, relative measures are used to assess forecast quality. An application with experimental forecasts for the Des Moines River basin illustrates the app... | eng_Latn | 23,516 |
The energy functional of the classical electroweak sphaleron at a finite mixing angle [theta][sub [ital W]] has a residual U(1) gauge symmetry. Several choices of gauge, which seem natural, lead to singular configurations for the sphaleron solution. | We present the general ansatz, the energy density, and the Chern-Simons charge for static axially symmetric configurations in the bosonic sector of the electroweak theory. Containing the sphaleron, the multisphalerons, and the sphaleron-antisphaleron pair at finite mixing angle, the ansatz further allows the construction of the sphaleron and multisphaleron barriers and of the bisphalerons at finite mixing angle. We conjecture that further solutions exist. | Since the inception of IEEE 802.11 wireless local area networks (WLANs) in 1997, wireless networking technologies have tremendously grown in the last few decades. The fundamental IEEE 802.11 physical (PHY) and medium access control (MAC) protocols have continuously been enriched with new technologies to provide the last mile wireless broadband connectivity to end users. Consequently, several new amendments of the basic IEEE 802.11 gradually came up in the forms of IEEE 802.11a, IEEE 802.11b, and IEEE 802.11g. More recently, IEEE 802.11n, IEEE 802.11ac, and IEEE 802.11ad are introduced with enhanced PHY and MAC layers that boost up physical data rates to the order of Gigabit per second. So, these amendments are generally known as high throughput WLANs (HT-WLANs). In HT-WLANs, PHY layer is enhanced with multiple-input multiple-output antenna technologies, channel bonding, short guard intervals, enhanced modulation and coding schemes. The MAC sublayer overhead is reduced by introducing frame aggregation and block acknowledgement technologies. However, several existing studies reveal that, many a time, the aforesaid PHY and MAC enhancements yield negative impact on various upper layer protocols, that is end-to-end transport and application layer protocols. As a consequence, a large number of researchers have focused on improving the coordination among PHY/MAC and upper layer protocols. In this survey, we discuss impact of HT-WLAN PHY and MAC layer enhancements on various transport and application layer protocols. This paper also summarizes several research works that use aforesaid enhancements effectively to boost up data rate of end-to-end protocols. We also point out limitations of the existing researches and list down different open challenges that can be meaningfully explored for the development of the next generation HT-WLAN technologies. | eng_Latn | 23,517 |
In this article we conduct an experimental study of the enhanced distributed channel access mechanism of the upcoming 802.11e standard. The main focus of the study is on two applications of EDCA: traffic engineering and service guarantees. With traffic engineering we aim at distributing the bandwidth in the WLAN according to a given throughput allocation criterion. With service guarantees the objective is to ensure that the performance metrics (throughput and delay) experienced by a station meet a given quality criterion. We build a testbed with wireless cards that support a substantial subset of the EDCA functionality and analyze performance against different sets of requirements. Experimental results show that EDCA can effectively be used for traffic engineering purposes. The goal of providing service guarantees with EDCA is shown to be more challenging; we identify future research directions that need to be addressed in order to achieve this goal. | Wireless Sensor Networks (WSNs) recently find extensive applications in remote disaster and health monitoring, where traffic prioritization is extremely essential for timely dissemination of critical information to the first responders. Though several resource control standards exist for general wireless networks, supporting differentiated traffic services (Quality-of-Service (QoS)) at the Medium Access Control layer for sensor networks need exclusive investigation and significant improvements. Particularly, the network treatment for disaster or medical emergencies needs to be exclusive (deterministic guarantees) rather than probabilistic guarantees as in most wireless QoS standards. In this paper, we introduce channel service preemptions during random medium access in WSNs. In the context of time-critical sensor applications, emergency traffic will have the privileges to interrupt the services of other routine traffic in the network to guarantee the lowest possible channel access latencies. We design our methodology within the QoS framework of the popular 802.11e EDCA standard and demonstrate the importance of service preemptions for emergency reporting. The performance analysis predicts close to 50% uniform decrease in emergency medium access delays when using our Channel Preemptive-EDCA (CP-EDCA) as compared to EDCA. The results also depict that CP-EDCA guarantees the lowest delay bounds and immunity to the presence of other lower priority traffic, for emergency frames, even under high network loads. The cost, however, is increased delays for routine traffic, which is acceptable during emergency sensor reporting. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 23,518 |
Opportunistic routing has been extensively studied and utilized in delay/disruption-tolerant networks. The extensive use of nodes' local information, e.g., the distance to the destination or the contact frequency with the destination, in such routing schemes can cause severe security and privacy problems. Existing solutions of anonymous routing can introduce undesired overhead and fail to provide the confidentiality of the routing metric. In this paper, we propose an advanced framework for opportunistic routing schemes, providing the following properties: confidentiality of the nodes' routing metric, anonymous authentication, and efficient key agreement for pairwise communication. A comprehensive evaluation, including security analysis, efficiency analysis, and simulation evaluation, is presented to show the security and feasibility of the proposed framework. | Opportunistic forwarding mechanism in delay tolerant networks (DTN) makes the network exposed to vulnerabilities. Providing security to existing routing protocols available for delay tolerant network becomes very difficult due to unavailability of sufficient contacts. It is necessary to design a secure routing protocol to overcome these issues. Energy is one of the crucial parameters in data forwarding and incentives should be offered to vehicular DTN nodes on the basis of energy spent for a particular message. This paper presents the secure routing mechanism which is based on the trust value of the vehicular DTN nodes. Incentive scheme is based on energy spent by the vehicular DTN node for forwarding data successfully. Routing is based on the trust value of the vehicular DTN nodes and incentive will be offered on successful delivery of the message. A source node offers the payment for successful delivery based on the time in which the message is delivered. The trust authority evaluates the credit and trust value for the participating vehicular DTN nodes based on energy and efforts put in successful delivery of the message. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 23,519 |
Railway signaling systems have the function of controlling the movement of rolling stock on the railway network without compromising security. Nowadays, signaling systems in operation in the U.K., rely on a physical interconnection grid for power supplying and data transferring, causing a high cost of implementation and maintenance related to infrastructure. In a previous paper [1], a ZigBee-based network was proposed as a modular low power wireless alternative for railway signaling systems, and studied in a synthetic environment created in a reverberation chamber (RC) in presence of realistic sources of EM interference. The performance of the ZigBee modules used, shown a persistent communication even in presence of high sources of interference, allowing the transference of information. Based on the previous, a complete multi-node signaling system was designed and implemented. In this paper, the performance of a low power communication system is studied and measured in a realistic environment where multiple elements such as rolling stock, power lines, and sources of interference are present. Additionally, the utilization of radio-frequency identification (RFID) technology has been included as part of train detection system, essential to control the movements of rolling stock, restricted by the Limit of Movement Authorities (LMA), which are a set of rules to keep coordination among the railway network and avoid collisions. Whilst a fuller knowledge of train location may allow train operators to allocate a greater number of rolling stock on the same railway network the adoption of the RFID tagging of items of rolling stock may be used in the wider context of asset management. | The 802.11b physical protocols applied in Communication Based Train Control (CBTC) Train-Ground communication system are simulated in this paper, and the simulation result is used to determine the AP distance. The train speed impact on physical FER is also studied by the simulation result. As a protocol used in a fully mobile outdoor environment, the packet delay and packets loss rate performance of 802.11 DCF is analyzed at last. | By using a superluminescent diode as the light source and a depolariser inside the fibre coil, a constant scale factor is achieved without using polarisation control elements. For long-term behaviour an RMS-bias drift of 10 degrees/h is obtained. | eng_Latn | 23,520 |
Opportunistic Routing is emerging as a promising paradigm to mitigate performance degradation in wireless multi-hop networks due to lossy links and varying channel conditions. Opportunistic routing protocols exploit the broadcast nature of the wireless medium to perform hop-by-hop route construction, and to take advantage of path diversity. However, most of the existing solutions impose a-priori constraints on the set of candidate forwarders that can be used when routing a packet. In this paper, we describe MaxOPP, a flexible and adaptive opportunistic routing algorithm able to select at each hop, and at run-time, the candidate forwarders that can maximize the opportunistic throughput gain. Thus, forwarding decisions in MaxOPP are dynamically adapted to variations of network conditions, ensuring an efficient trade-off between reliability and opportunistic benefit. Simulations conducted with NS-2 on a set of representative scenarios show that MaxOPP achieves higher throughput for bulk data transfers than traditional shortest-path routing. | Considerable research has focused on the design of routing protocols for wireless mesh networks. Yet, little is understood about the stability of routes in such networks. This understanding is important in the design of wireless routing protocols, and in network planning and management. In this paper, we present results from our measurement-based characterization of routing stability in two network deployments, the UCSB MeshNet and the MIT Roofnet. To conduct these case studies, we use detailed link quality information collected over several days from each of these networks. Using this information, we investigate routing stability in terms of route-level characteristics, such as prevalence, persistence and flapping. Our key findings are the following: wireless routes are weakly dominated by a single route; dominant routes are extremely short-lived due to excessive route flapping; and simple stabilization techniques, such as hysteresis thresholds, can provide a significant improvement in route persistence. | Since the end of the Cold War, the study of European defence has been dominated by a ‘Common Security and Defence Policy (CSDP)-centric’ approach, while largely neglecting the comparative analysis ... | eng_Latn | 23,521 |
The measurement of CTD is the key of oceanic research. The conventional methods have lots of limitations. Ad Hoc wireless sensor network is built from sensor nodes that may spontaneously create, assemble themselves, dynamically adapt to manage movement of sensor nodes, which is most suitable to the CTD measurement. The positions of CTD sensors detected by GPS are changed by waves, which leads to the changes of network topology and may increase the energy consumption. Two steps are taken to enhance the life of the network. First is the adoption of energy efficient routing protocols based on rCAMP. Second is the data compression. Then data are transferred to control center and processed by B-Spline algorithm to build the ocean CTD model. | This paper presents a novel multicast routing protocol for mobile ad hoc wireless networks. The protocol, termed ODMRP (on-demand multicast routing protocol), is a mesh-based, rather than a conventional tree-based multicast scheme and uses a forwarding group concept (only a subset of nodes forwards the multicast packets via scoped flooding). It applies on-demand procedures to dynamically build routes and maintain multicast group membership. ODMRP is well suited for ad hoc wireless networks with mobile hosts where bandwidth is limited, topology changes frequently, and power is constrained. We evaluate ODMRP's scalability and performance via simulation. | Using the thyromental distance (TMD) measured based on the ultrasonographic location of the thyroid cartilage prominence as the criterion, we investigated the accuracy of TMD measurement by surface landmark identification of the thyroid cartilage prominence. Twenty-nine anesthetist resident volunteers were recruited, including 10 first-year residents, 9 second-year residents and 10 third-year residents. Each volunteer measured the other 28 volunteers’ TMD. Then, the thyroid cartilage prominence of each volunteer was identified by ultrasonography of the junction of the vocal cord and thyroid cartilage, and the TMD was measured precisely. The error of the TMD measurement was determined by the minimal detectable difference (MDD) compared to the ultrasound measurement. A difference of greater than 5.4 mm between the TMD measured by volunteers and that based on ultrasound localization was defined as a measurement error. The measurement error rate of females’ TMD was significantly higher than that of males’ (50 vs 10%, P < 0.001). The error rates of anesthetist residents of first-year, second-year and third-year were 34, 27, and 31%, respectively, and were not significantly different. The error of TMD measurement by surface landmark identification is often, especially for women. More clinic experience don’t improve it. | eng_Latn | 23,522 |
Localized Algorithms and Their Applications in Ad Hoc Wireless Networks | Distributed heuristics for connected dominating sets in wireless ad hoc networks | Aldosterone Is Not Associated With Metabolic and Microvascular Insulin Sensitivity in Abdominally Obese Men | eng_Latn | 23,523 |
Employing Chaotic Encryption for IEEE 802.15.4-based LR-WPANs | Employing IEEE 802.15.4 for Quality of Service Provisioning in Wireless Body Area Sensor Networks | High-affinity glucose uptake in Saccharomyces cerevisiae is not dependent on the presence of glucose-phosphorylating enzymes | eng_Latn | 23,524 |
Investigating Coverage and Connectivity Trade-offs in Wireless Sensor Networks: The Benefits of MOEAs | On solving coverage problems in a wireless sensor network using voronoi diagrams | Microtubule capture by CENP-E silences BubR1-dependent mitotic checkpoint signaling | eng_Latn | 23,525 |
Minimum Data-Latency-Bound $k$-Sink Placement Problem in Wireless Sensor Networks | Optimal Multi-sink Positioning and Energy-Efficient Routing in Wireless Sensor Networks | Sensorless vector and direct torque control | kor_Hang | 23,526 |
SR-MAC: A Low Latency MAC Protocol for Multi-Packet Transmissions in Wireless Sensor Networks | A Novel MAC Protocol for Event-Based Wireless Sensor Networks: Improving the Collective QoS | Mounting evidence against the role of ICC in neurotransmission to smooth muscle in the gut | eng_Latn | 23,527 |
Joint Optimization of Smart Antenna System and Wireless Mesh Network | A MAC protocol for full exploitation of directional antennas in ad-hoc wireless networks | SNARE Function Is Not Involved in Early Endosome Docking | eng_Latn | 23,528 |
Congestion Control Analysis over Wireless Ad hoc Networks | An improved congestion avoidance control model for TCP Vegas based on Ad Hoc networks | High-speed running performance is largely unaffected by hypoxic reductions in aerobic power | eng_Latn | 23,529 |
The Sentinel Problem for a Multi-hop Sensor Network | Link scheduling in sensor networks: distributed edge coloring revisited | Sensorless vector and direct torque control | eng_Latn | 23,530 |
Demo: MeshSim: A Wireless Ad-Hoc Network Development Platform | GloMoSim: A Library for Parallel Simulation of Large-Scale Wireless Networks | CIP, a cardiac Isl1-interacting protein, represses cardiomyocyte hypertrophy. | eng_Latn | 23,531 |
Improvement and Simulation of LEACH Routing Protocol in Wireless Sensor Networks | A Hierarchical and Clustering Strategy for Routing in WSN Based on Ant Colony Optimization | Toll-Like Receptor Signalling Is Not Involved in Platelet Response to Streptococcus pneumoniae In Vitro or In Vivo | eng_Latn | 23,532 |
QoE-driven dissemination of real-time videos over vehicular networks | A New Improved GPSR (GPSR-kP) Routing Protocol for Multimedia Communication over Vehicular Ad hoc Network | Quantitative real-time reverse transcription polymerase chain reaction: normalization to rRNA or single housekeeping genes is inappropriate for human tissue biopsies. | eng_Latn | 23,533 |
An application of routing protocols for Vehicular Ad-hoc Networks | Hello message scheme enhancement in CRMANET | High-speed running performance is largely unaffected by hypoxic reductions in aerobic power | eng_Latn | 23,534 |
Admission control and flow termination in mobile ad-hoc networks with Pre-congestion Notification | Optimized Link State Routing Protocol (OLSR) | High-speed running performance is largely unaffected by hypoxic reductions in aerobic power | eng_Latn | 23,535 |
Zigbee and wireless local area networks (WLAN), based on IEEE 802.15.4 and IEEE 802.11 standards, respectively, operate in overlapping unlicensed frequency bands. Therefore, one network can create harmful interference for the other if they are located in the same geographical area. The coexistence performance of the two networks has been analyzed mostly via computer simulation in the literature. In this paper, we develop a mathematical model to evaluate the throughput performance of coexisting 802.15.4 Zigbee network and 802.11 WLAN operating on the same channel. Our proposed analytical model is based on the analysis of a Markov chain for one pair of typical WLAN-Zigbee nodes, which capture detailed operations and interactions of the MAC protocols in the two networks. Moreover, we propose to employ the developed model for channel allocation that achieves fair throughput sharing among Zigbee nodes. Numerical results confirm the excellent accuracy of the proposed model and its usefulness for coexistence performance evaluation and design of the heterogeneous network. | Coexistence issues between IEEE 802.11b wireless communication networks and IEEE 802.15.4 wireless sensor networks, operating over the 2.4-GHz industrial, scientific, and medical band, are assessed. In particular, meaningful experiments that are performed through a suitable testbed are presented. Such experiments involve both the physical layer, through measurements of channel power and the SIR, and the network/transport layer, by means of packet loss ratio estimations. Different configurations of the testbed are considered; major characteristics, such as the packet rate, the packet size, the SIR, and the network topology, are varied. The purpose of this paper is to gain helpful information and hints to efficiently face coexistence problems between such networks and optimize their setup in some real-life conditions. Details concerning the testbed, the measurement procedure, and the performed experiments are provided. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 23,536 |
Supratentorial primitive neuro-ectodermal tumors (PNET) in adults are very rare. Extraneural metastasis are unusual and the optimal palliative chemotherapy regimen is not established. We present a 26-year-old patient with local recurrence and distant metastasis of supratentorial PNET successfully treated with intensive induction chemotherapy and maintenance temozolomide. | Brain tumours comprise only 2% of all adult cancers, but they are among the most debilitating malignant diseases. Temozolomide, an alkylating agent that can be administered orally, has been approved for the treatment of recurrent malignant glioma on a daily schedule for 5-day cycles. Continuous administration schedules with a higher dose intensity are being explored, but an improvement in efficiency remains to be shown. The benefit from temozolomide given as a single agent in recurrent disease will be several weeks at best. This drug is therefore now undergoing clinical testing as neoadjuvant chemotherapy or with concomitant radiotherapy in patients with newly diagnosed glioma. Several phase I trials are investigating the combination of temozolomide with other agents active against brain tumours. This review briefly summarises the pharmacological background and clinical development of temozolomide and focuses on current and future clinical exploration of this drug for the treatment of brain tumours. | A Mobile Ad hoc NETwork (MANET) could establish a communication in network infrastructure-less places. In an ad hoc network, a basic IPv6 address auto-configuration mechanism has an address allocation problem. A number of address allocation mechanisms have been suggested. However, mobile node(MN)s have high mobility and random address. Therefore, they do not guarantee fixed and shared network prefix. To guarantee equality of network prefix among connected MNs, we propose a MANET identifier (MANET.ID). This scheme allows MNs to share the same MANET_ID using a creation & negotiation phase. By sharing an equal MANET_ID, we achieve a number of enhancements for existing ad hoc network technologies: Enhanced group communication, avoiding duplicate address detection storms, and enhanced zone routing protocol (ZRP). | eng_Latn | 23,537 |
The “Union of the Comoros” is a volcanic archipelago nation in the Indian Ocean, consisting of three islands. About half the population lives below the international poverty line of US$1.25 a day. The interiors of the islands vary from steep mountains to low hills with mostly damaged or unconstructed roads to interconnect the several islets. This situation represents an extraordinary field test: the geographical isolation from other Countries, among the islands and within the same island, the development level of the population and the lack of infrastructures can be efficiently mitigated if a high capacity ICT infrastructure is realized, in order to provide social services (distance learning, telemedicine, financial administration) to the population, together with the possibility to access basic information on the Internet. In this context, we have put into practice a wireless network based on the use of low cost components, optimized for the transportation of large amount of bandwidths (minimum measured throughput is 65 Mb/s). The infrastructure has been made available at no cost for the people, since an extremely small percentage of them can afford regular Internet subscriptions. The network provides interconnectivity among the islets and local Hot Spot facilities at the islet level, free of cost for the end users. The local population has been recruited during the design and installation phase, in order to develop sufficient know how that allows them to maintain and even extend the infrastructure after its completion. Accessibility is guaranteed over the whole Country. To this aim, technical tests have been made in order to verify the affordability and reliability of the solution in the medium and long terms. The project is now being used to vehicle public finance management among the multitude of islets of the islands, under the endorsement of the World Bank. | Low cost digital radios are sometimes proposed as an affordable tool for the realization of long distance (multikilometric - MKM) point-to-point telecommunication infrastructures in Developing Countries. To analyze the performance and the reliability of an architecture based on use of cheap wireless cards, several point-to-point links ranging from 50 up to 300 kilometers have been implemented in harsh environments. The links make use of commercial IEEE802.11x compliant radios. To reach long distances, off the shelf 802.11-derived communication protocols have been implemented, as well as a simplified proprietary solution employing few minor modifications to the PHY and MAC layers of the standard. Data rate enhancements have been obtained combining and transmitting several channels through the same antenna. Performance and stability have been monitored, continuously, for about 18 months. Reliability and scalability have been analyzed, taking into account the complexity of different kinds of scenarios. Interesting results have been reported, showing that, thanks to its inexpensive features, this technological solution may be used as a starting process to realize backhaul links and transport wideband connectivity in poor and isolated regions. | Blunt trauma abdomen rarely leads to gastrointestinal injury in children and isolated gastric rupture is even rarer presentation. We are reporting a case of isolated gastric rupture after fall from height in a three year old male child. | eng_Latn | 23,538 |
1μm gate GaAs MESFETs with AlGaAs/GaAs buffer layers were grown on (100) InP substrates by low-pressure MOCVD. The linewidth of the X-ray rocking curve on this material is 315 arc seconds. Device transconductance of 220mS/mm and output conductance of l.2 mS/mm were achieved. | DC and microwave characteristics of GaAs metal-semiconductor field-effect transistors (MESFETs) on InP grown using the chloride close-proximity reactor (CPR) system are reported. The FETs have an extrinsic maximum transconductance of 210 mS/mm for a drain saturation current of 110 mA/mm, a cutoff frequency of unity current gain of 13 GHz, and a maximum frequency of oscillation of 21 GHz. The dislocation density in a 1.6- mu m GaAs layer on InP is 10/sup 8/ cm/sup -2/ measured from cross-sectional transmission electron microscopy (TEM). The full width at half maximum of | The IEEE 802.15.4 standard for wireless sensor networks can support energy efficient, reliable, and timely packet transmission by tuning the medium access control parameters macMinBE, macMax-CSMABackoffs, and macMaxFrameRetries. Such a tuning is difficult, because simple and accurate models of the influence of these parameters on the probability of successful packet transmission, packet delay and energy consumption are not available. Moreover, it is not clear how to adapt the parameters to the changes of the network and traffic regimes by algorithms that can run on resource-constrained nodes. In this paper, an effective analytical model is used to derive an adaptive algorithm at the medium access control layer for minimizing the power consumption while guaranteeing reliability and delay constraints in the packet transmission. The algorithm does not require any modifications of the IEEE 802.15.4 standard and can be easily implemented on existing network nodes. Numerical results show that the analysis is accurate, that the proposed algorithm satisfies reliability and delay constraints, and ensures a longer lifetime of the network under both stationary and transient network conditions. | eng_Latn | 23,539 |
Wireless sensor networks are a family of networks in wireless communication system and have the potential to become significant subsystem of engineering applications. In view of the fact that the sensor nodes in wireless sensor networks are typically irreplaceable, this type of network should operate with minimum possible energy in order to improve overall energy efficiency. Therefore, the protocols and algorithms developed for sensor networks must incorporate energy consumption as the highest priority optimization goal. Since the base station in sensor networks is usually a node with high processing power, high storage capacity and the battery used can be rechargeable, the base station can be utilized to collect data from each sensor node in the sensing area by moving closer to the transmitting node. In this paper, we proposed an energy-efficient protocol for the movement of mobile base station using particle swarm optimization (PSO) method in wireless sensor networks. Simulation results demonstrate that the proposed protocol can improve the network lifetime, data delivery and energy consumption compared to existing energy-efficient protocols developed for this network. | Wireless distributed microsensor systems will enable the reliable monitoring of a variety of environments for both civil and military applications. In this paper, we look at communication protocols, which can have significant impact on the overall energy dissipation of these networks. Based on our findings that the conventional protocols of direct transmission, minimum-transmission-energy, multi-hop routing, and static clustering may not be optimal for sensor networks, we propose LEACH (Low-Energy Adaptive Clustering Hierarchy), a clustering-based protocol that utilizes randomized rotation of local cluster based station (cluster-heads) to evenly distribute the energy load among the sensors in the network. LEACH uses localized coordination to enable scalability and robustness for dynamic networks, and incorporates data fusion into the routing protocol to reduce the amount of information that must be transmitted to the base station. Simulations show the LEACH can achieve as much as a factor of 8 reduction in energy dissipation compared with conventional outing protocols. In addition, LEACH is able to distribute energy dissipation evenly throughout the sensors, doubling the useful system lifetime for the networks we simulated. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 23,540 |
In this study, we evaluate the performance of three types of techniques, namely neural based, Kalman filter based and trilateration based techniques, having been proposed to tackle the problem of real-time mobile sensor node tracking in a wireless sensor network with passive architecture. To investigate the performance of the aforementioned techniques under real-world circumstances, a small-scale wireless sensor network is deployed in an environment prone to multiple noise sources, multi-path and signal attenuation phenomena. The network makes use of a 433MHz MICA2 based Cricket platform, which is comprised of 6 Cricket motes, at least one of which is mobile. The network utilizes a passive architecture in which any mobile mote receives the Beacon signals to localize itself. Subsequently, a neural based approach is compared with a trilateration and a Kalman filter based technique. The results obtained corroborate the efficiency and advanced performance of the neural based approach. | The IEEE 802.15.4 protocol offers great potential in several application fields, such as industrial Wireless Sensor Networks (WSNs). An industrial automation cell (field level) is characterized mostly by periodic traffic flows. Using the IEEE 802.15.4 protocol, it is necessary to manage Guaranteed Time Slots (GTSs) allocation and at the same time ensure adequate performance both to other periodic traffic flows and network management/control flows. For these reasons, this paper shows a flexible approach in order to improve GTSs assignment and medium access performance. Analytical results are shown in order to demonstrate benefits introduced by deadline-aware algorithm (for guaranteed access to reserved slots) and CSMA-CA-priority based (for latencies reduction during medium access attempts). Otherwise, obtained results show that the proposed technique improves the number of deadlines met and the probability to find the channel free for transmissions. | The controversy over Shirin Neshat's representations of Muslim women has been dominated by interpretations that use an unexamined liberatory model of agency to understand the artist and her subjects. Consequently, criticism of Neshat has become polarized by readings of Islam and women's agency as fundamentally incompatible, and the possibility of female subjects whose agency is grounded in and who aspire to Islamic values has been ignored. Using Saba Mahmood's theory of non-liberatory agency as a way to approach women's embodiment in Islamic culture, this article provides re-readings of the films Turbulent, Rapture and Fervor that suggest how Neshat's art can be read as depicting pious Islamic modes of embodiment. | eng_Latn | 23,541 |
The network topology changes frequently in ad-hoc networks. Some on-demand protocols with multi-paths or backup routes have been proposed to improve the performance in ad-hoc networks. AODV-BR scheme improves AODV routing protocols by constructing a mesh structure and providing multiple alternate routes. The algorithm establishes the mesh and multi-path using the RREP of AODV, which does not transmit many control messages. In this paper, we propose two schemes: AODV-ABR and AODV-ABL to increase the adaptation of routing protocols to topology changes by modifying AODV-BR. In AODV-ABR, the alternative route can be created by overhearing not only RREP packets but also data packets. AODV-ABL combines the benefits of AODV-ABR and Local repair. Finally, we evaluate the performance improvement by simulations. | An ad-hoc network is the cooperative engagement of a collection of Mobile Hosts without the required intervention of any centralized Access Point. In this paper we present an innovative design for the operation of such ad-hoc networks. The basic idea of the design is to operate each Mobile Host as a specialized router, which periodically advertises its view of the interconnection topology with other Mobile Hosts within the network. This amounts to a new sort of routing protocol. We have investigated modifications to the basic Bellman-Ford routing mechanisms, as specified by RIP [5], to make it suitable for a dynamic and self-starting network mechanism as is required by users wishing to utilize ad hoc networks. Our modifications address some of the previous objections to the use of Bellman-Ford, related to the poor looping properties of such algorithms in the face of broken links and the resulting time dependent nature of the interconnection topology describing the links between the Mobile Hosts. Finally, we describe the ways in which the basic network-layer routing can be modified to provide MAC-layer support for ad-hoc networks. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 23,542 |
This paper describes a new implementation of the Elastic Multicast (EM) protocol including new design enhancements for improved dynamic operation. The paper also presents additional performance data collected from emulation-based mobile network experiments. EM is a low complexity extension to Simplified Multicast Forwarding (SMF) that adds group-specific dynamic pruning of the SMF-based multicast forwarding mesh for higher rate traffic flows. It therefore reduces overhead by pruning the SMF relay sets in areas where no receivers exist. Our experimental emulation results show that, under a variety of mobility conditions and multicast group distribution patterns, EM maintains SMF-like data delivery robustness while significantly reducing overhead. We also demonstrate that a new design feature that provides preemptive ACK messages for active receiver groups leads to lower loss under mobility and sparse receiver groups. Based upon the results, we consider this feature critical to be included in any future EM design. We also present experimental results examining the performance of EM with classical flooding (CF) and connected dominating set (CDS) relay modes. We show, for the experiments examined, that CF provides some reduced loss with minimal additional overhead when used with EM. We also discuss future work and ongoing issues. | This paper presents design issues and performance analysis of optimized cover set algorithms supporting Simplified Multicast Forwarding (SMF) of data plane traffic within mobile ad hoc network (MANET) environments. SMF is presently being developed within the Internet Engineering Task Force (IETF) as an experimental specification to provide simplified multicast data dissemination among multi-hop, wireless nodes within peer MANET routing neighborhoods. The SMF protocol allows for a variety of cover set reduction techniques to optimize the simplified data flooding and relaying process amongst routing peers. A variety of distributed algorithms for forming connected dominating sets (CDS) are being considered as mechanisms to reduce the cover set. This paper presents modeling and analysis work of various CDS relay set algorithms and demonstrates working code within an SMF implementation. We provide a brief problem background, discuss models and scenarios, compare various algorithms, and then summarize observations as well as discuss future work. A main purpose of the paper is to begin examining the robustness of the algorithms to mobility and increasing multicast traffic load. We examine the results against a classical flooding baseline for comparison. We observe similar efficiency and robustness performance for several forwarding algorithms of interest. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 23,543 |
Significant progress has been made towards making ad hoc networks secure and DoS resilient. In this paper, we study DoS attacks in order to assess the damage that difficult-to-detect attackers can cause. The first attack we study, called the JellyFish attack, is targeted against closed-loop flows such as TCP; although protocol compliant, it has devastating effects. The second is the Black Hole attack, which has effects similar to the JellyFish, but on open-loop flows. The interesting point to note here is DoS attacks can increase the capacity of ad hoc networks, as they starve multi-hop flows and only allow one-hop communication, a capacitymaximizing, yet clearly undesirable situation. Later in this paper we study different techniques to protect our ad hoc networks against these denial-of-service attacks. The mechanisms described here seek to limit the damage sustained by ad hoc networks from intrusion attacks and allow for continued network operation at an acceptable level during such attacks. These mechanisms are designed to handle attacks on the routing traffic as well as the data traffic in ad hoc networks thereby providing a comprehensive defense against intruders. These techniques are routing algorithm independent. These mechanisms may be viewed as providing general design principles and techniques the can be incorporated within a number of existing ad hoc routing algorithms to make them robust to intrusion attacks. | Mobile Adhoc NETworks (MANETs) have gained popularity in both research and industrial domains due to their on-demand ad-hoc nature, easy deployment and absence of any central authority for routing. However, MANETs are susceptible to an array of attacks, primarily because of their adhoc and decentralized nature. Most of these attacks are targeted at disrupting the routing of control and data packets, thereby rendering MANETs insecure and unusable. Denial of Service (DoS) attack is a suite of attacks consisting of attacks like Blackhole, Grayhole attack etc. in which the network traffic is captured and forwarded to a malicious node or a group of collaborating malicious nodes in the network so as to hamper legitimate communications in the network. The scope of this paper is to study the effects of Blackhole, Grayhole, Rushing and Sleep Deprivation attacks in Adhoc On-Demand Distance Vector (AODV) based MANETs. Various performance metrics have been used to study the effects of different DoS attacks in MANETs and a comprehensive analysis is presented. NS-2.35 has been used extensively to simulate these attacks. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 23,544 |
In multi-hop wireless ad-hop networks, designing energy-efficient routing protocols is critical since nodes are power-constrained. However, it is also an inherently hard problem due to two important factors: First, the nodes may be mobile, demanding the energy-efficient routing protocol to be fully distributed and adaptive to the current states of nodes; Second, the wireless links may be uni-directional due to asymmetric power configurations of adjacent nodes. In this paper, we propose a location-aided power-aware routing protocol that dynamically makes local routing decisions so that a near-optimal power-efficient end-to-end route is formed for forwarding data packets. The protocol is fully distributed such that only location information of neighboring nodes are exploited in each routing node. Through rigorous theoretical analysis for our distributed protocol based on greedy algorithms, we are able to derive critical global properties with respect to end-to-end energy-efficient routes. Finally, preliminary simulation results are presented to verify the performance of our protocol. | Wireless networks are susceptible to localized disruptions, due to the shared nature of the medium. Radio jamming, the most common type of localized disruption causes wireless link failures. Jamming mitigation has been traditionally addressed in the physical and MAC layers. Such approaches come with added complexity and often require specialized hardware. We investigate whether a generally applicable routing layer approach, based on multipath routing coupled with power control, can mitigate the effects of jamming. We propose (1) proactive protection and (2) reactive protection techniques for jamming mitigation in wireless multihop networks with fixed nodes. For reactive protection, we propose a distributed geographic routing algorithm that finds alternative route to the destination, starting from the first node with failed link on the original path. We evaluate the performance of this algorithm using OPNET simulations. | Since the end of the Cold War, the study of European defence has been dominated by a ‘Common Security and Defence Policy (CSDP)-centric’ approach, while largely neglecting the comparative analysis ... | eng_Latn | 23,545 |
Wireless Sensor Networks (WSNs) are formed by deploying as large number of sensor nodes in an area for the surveillance of generally remote locations. A typical sensor node is made up of different components to perform the task of sensing, processing and transmitting data. WSNs are used for many applications in diverse forms from indoor deployment to outdoor deployment. The basic requirement of every application is to use the secured network. Providing security to the sensor network is a very challenging issue along with saving its energy. Many security threats may affect the functioning of these networks. WSNs must be secured to keep an attacker from hindering the delivery of sensor information and from forging sensor information as these networks are build for remote surveillance and unauthorized changes in the sensed data may lead to wrong information to the decision makers. This paper gives brief description about various security issues and security threats in WSNs. | Pervasive micro-sensing and actuation may revolutionize the way in which we understand and manage complex physical systems: from airplane wings to complex ecosystems. The capabilities for detailed physical monitoring and manipulation offer enormous opportunities for almost every scientific discipline, and it will alter the feasible granularity of engineering. We identify opportunities and challenges for distributed signal processing in networks of these sensing elements and investigate some of the architectural challenges posed by systems that are massively distributed, physically-coupled, wirelessly networked, and energy limited. | Wireless Sensor Networks (WSNs) are a new technology that has received a substantial attention from several academic research fields in the last years. There are many applications of WSNs, including environmental monitoring, industrial automation, intelligent transportation systems, healthcare and wellbeing, smart energy, to mention a few. Courses have been introduced both at the PhD and at the Master levels. However, these existing courses focus on particular aspects of WSNs (Networking, or Signal Processing, or Embedded Software), whereas WSNs encompass disciplines traditionally separated in Electrical Engineering and Computer Sciences. This paper gives two original contributions: the essential knowledge that should be brought in a WSNs course is characterized, and a course structure with an harmonious holistic approach is proposed. A method based on both theory and experiments is illustrated for the design of this course, whereby the students have hands-on to implement, understand, and develop in practice the implications of theoretical concepts. Theory and applications are thus considered all together. Ultimately, the objective of this paper is to design a new course, to use innovative hands-on experiments to illustrate the theoretical concepts in the course, to show that theoretical aspects are essential for the solution of real-life engineering WSNs problems, and finally to create a fun and interesting teaching and learning environments for WSNs. | eng_Latn | 23,546 |
Wireless ad hoc networks have been of significant interest in the communications engineering field within the last decades. Due to their flexibility and relatively low infrastructure and front end expenses, wireless ad hoc networks promise a wide application spectrum. To understand their expected performance, interference limited scenarios must be considered and an interference analysis based on the spatial distribution of the network nodes is necessary. This analysis must cover the randomness of this spatial distribution. The authors have considered the stochastic geometry tools as basic means for this analysis. The randomness of the individual spatial distribution realizations can thus be decoupled from the interference analysis by collecting the statistics over multiple particular spatial network distributions, which eases the analysis. In this manuscript the authors illustrate a simulation framework for the investigation of the performance of wireless ad hoc networks. The simulation results for the various spatial node densities are discussed for both distribution types by taking the interference limited scenarios into account. Also, theoretical performance bounds are shown which allow the verification of the stochastic simulation. | Preface. Preface to Volume II. Contents of Volume II. Part IV Medium Access Control 1 Spatial Aloha: the Bipole Model 2 Receiver Selection in Spatial 3 Carrier Sense Multiple 4 Code Division Multiple Access in Cellular Networks Bibliographical Notes on Part IV. Part V Multihop Routing in Mobile ad Hoc Networks: 5 Optimal Routing 6 Greedy Routing 7 Time-Space Routing Bibliographical Notes on Part V. Part VI Appendix:Wireless Protocols and Architectures: 8 RadioWave Propagation 9 Signal Detection 10 Wireless Network Architectures and Protocols Bibliographical Notes on Part VI Bibliography Table of Notation Index. | This article investigates the design of constraint hoops in the aeronautical hydraulic pipeline system. Non-probabilistic sensitivity analysis is used to screen out the hoops which are insensitive ... | eng_Latn | 23,547 |
Multicast routing technology of wireless sensor network is a method of transferring specific data to a group of clients selectively; therefore, quality of the services is the key to evaluate the method. Based on AODVjr algorithm, we improved an energy confinement QoS multicast routing algorithm, which takes the energy cost into account, allowing the node in the multicast trees to meet the energy constraints when establishing the minimum cost paths. Test results show that the algorithm can obtain better energy balance, and improve network service lifetime in energy-sensitive multicast applications. | In wireless sensor networks congestion occurs in intermediate nodes while data packets travel from source to sink. Congestion causes packet loss which in turn drastically decreases network performance and throughput As sensors are energy constraint so it is a decisive task to detect the congestion and congested regions in a network to perform congestion control. In addition to that different application i.e. real time and non-real time data in sensor network have different QoS (delay, link utilization, and packet loss) guarantee requirement In this paper we proposed a new QoS adaptive cross-layer approach to control the congestion and support QoS guarantee for different application data in sensor network. This approach maintains two congestion control algorithm to control namely short-term and long-term congestion. To ensure real time and non-real time data flow, hop-by-hop QoS aware scheduling and QoS distributed MAC Manager are considered. The experimental outputs of this work are able to show that proposed scheme gives guaranteed QoS for different application data and gives a noticeable performance in terms of energy analysis and lifetime of the network. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 23,548 |
The existing data service providers have gaps in their connectivity, especially in disaster and remote underserved areas. A mesh network can address this shortcoming by providing Internet access to devices outside the coverage area with the help of other nearby devices. Mesh networks are homogeneous using a single interface across the network and require large-scale deployment of proprietary devices. We propose to build a heterogeneous mesh network using various interfaces such as Wi-Fi, Bluetooth, and cellular data services to connect devices. These interfaces are available in devices such as smartphones, laptops, and home automation devices and have the potential to be a convergence device. We present an Android application enabling devices with various interfaces to become convergence devices and build heterogeneous mesh networks to address the shortcoming of the existing wireless ISP services. We target this prototype implementation to provide a tactical communication link in disaster zones, enabling the public to build the network and send a life-critical distress signal calling for help. The proposed implementation achieved an average throughput of 1 Mbps with multiple hops and through Wi-Fi, Bluetooth, and cellular data service. | Now a days Unmanned Aerial Vehicles (UAVs) is being used for wide range of application. For example, UAVs are utilized to surveillance disaster affected and resource constrained network area and create the wide range of communication network. In this paper we proposed an Ad-hoc networked UAVs for Aerial Sensor Network for disaster management application and remote sensing. We used Wireless Mesh Network to connect multiple set of UAVs with each and other to increase the coverage of the observable area. We present an approach that works on the basis of process-patterns, each describing the context-dependent behavior of UAVs according to the execution order of services for different situations. Furthermore, the logical communication path is optimized within the mesh network based on each node's areal position using a dynamic hierarchical communication structure. As, this method we used wireless mash network for connecting one with another and do not required any existing network system, so it can be easily used over resource constrained networks, which are normally associated with any disaster or hazardous scenario. And we can also surveillance the complete area with bird eye view. | Channel Hot Carrier (CHC) degradation on uniaxially strained pMOS and nMOS samples with different S/D materials has been analyzed. The results show that the CHC damage is larger in the strained samples in comparison with the unstrained devices, and increases with the temperature. | eng_Latn | 23,549 |
We have applied a loop-mediated isothermal amplification (LAMP) technique to detect Leishmania don- ovani DNA. The LAMP technique detected 1 fg of L. donovani DNA, which was 10-fold more sensitive than a con- ventional polymerase chain reaction (PCR). All nested PCR-positive blood samples from visceral leishmaniasis patients were positive with the LAMP technique, and DNA samples from L. infantum , L. major , L. mexicana , L. tropica , L. braziliensis , Plasmodium falciparum , and healthy humans were negative with the LAMP technique. The advantages of the LAMP method are its shorter reaction time, a lack of requirement of sophisticated equipment, and visual judgment of positivity based on the turbidity of reaction mixture. Our LAMP technique can be a better alternative to a conventional PCR, especially under field conditions. | Summary There is a lack of effective, safe, and affordable pharmaceuticals to control infectious diseases that cause high mortality and morbidity among poor people in the developing world. We analysed outcomes of pharmaceutical research and development over the past 25 years, and reviewed current public and private initiatives aimed at correcting the imbalance in research and development that leaves diseases that occur predominantly in the developing world largely unaddressed. We compiled data by searches of Medline and databases of the US Food and Drug Administration and the European Agency for the Evaluation of Medicinal Products, and reviewed current public and private initiatives through an analysis of recently published studies. We found that, of 1393 new chemical entities marketed between 1975 and 1999, only 16 were for tropical diseases and tuberculosis. There is a 13-fold greater chance of a drug being brought to market for central-nervous-system disorders or cancer than for a neglected disease. The pharmaceutical industry argues that research and development is too costly and risky to invest in low-return neglected diseases, and public and private initiatives have tried to overcome this market limitation through incentive packages and public-private partnerships. The lack of drug research and development for "non-profitable" infectious diseases will require new strategies. No sustainable solution will result for diseases that predominantly affect poor people in the South without the establishment of an international pharmaceutical policy for all neglected diseases. Private-sector research obligations should be explored, and a public-sector not-for-profit research and development capacity promoted. | Wireless sensor networks consist of small battery powered devices with limited energy resources. Once deployed, the small sensor nodes are usually inaccessible to the user, and thus replacement of the energy source is not feasible. Hence, energy efficiency is a key design issue that needs to be enhanced in order to improve the life span of the network. Several network layer protocols have been proposed to improve the effective lifetime of a network with a limited energy supply. In this article we propose a centralized routing protocol called base-station controlled dynamic clustering protocol (BCDCP), which distributes the energy dissipation evenly among all sensor nodes to improve network lifetime and average energy savings. The performance of BCDCP is then compared to clustering-based schemes such as low-energy adaptive clustering hierarchy (LEACH), LEACH-centralized (LEACH-C), and power-efficient gathering in sensor information systems (PEGASIS). Simulation results show that BCDCP reduces overall energy consumption and improves network lifetime over its comparatives. | eng_Latn | 23,550 |
The efficiency of locating heat sources in a sensor network with the novel semantic-dependent two-tier gossip mechanisms is studied. Two-tier gossip mechanisms are probabilistic paradigms which can switch from one gossipee-selection scheme to another one, typically one that tends to select more nearby nodes. An upper time bound for two-tier gossip mechanism is presented. When semantic-dependent two-tier gossip mechanisms are employed, the selection of communication peers depends on information, for example temperature, obtained from the application layer. Distance from the heat source(s) can be estimated with the help of the local temperature detected, and the two-tier technique is also employed for further improvement. With uniform gossip as the benchmark, an overall improvement in both time and the communication distances required is observed. | Gossip-based communication protocols are attractive in cases where absolute delivery guarantees are not required due to their scalability, low overhead, and probabilistically high reliability. In earlier work, a gossip-based protocol known as gravitational gossip was created that allows the selection of quality ratings within subgroups based on workload and information update frequency. This paper presents an improved protocol that adds an adaptive component that matches the actual subgroup communication rates with desired rates coping with network variations by modifying underlying gossip weights. The protocol is designed for use in environments where many information streams are being generated and interest levels vary between nodes in the system. The gossip-based protocol is able to allow subscribers to reduce their expected workload in return for a reduced information rate. The protocol is a good fit for applications such as military information systems, sensor networks, and rescue operations. Experiments were conducted in order to compare the merits of different adaptation mechanisms. Experimental results show promise for this approach. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 23,551 |
Serious security threat is originated by node capture attacks in hierarchical data aggregation where a hacker achieves full control over a sensor node through direct physical access in wireless sensor networks. It makes a high risk of data confidentiality. In this study, we propose a securing node capture attacks for hierarchical data aggregation in wireless sensor networks. Initially network is separated into number of clusters, each cluster is headed by an aggregator and the aggregators are directly connected to sink. The aggregator upon identifying the detecting nodes selects a set of nodes randomly and broadcast a unique value which contains their authentication keys, to the selected set of nodes in first round of data aggregation. When any node within the group needs to transfer the data, it transfers slices of data to other nodes in that group, encrypted by individual authentication keys. Each receiving node decrypts, sums up the slices and transfers the encrypted data to the aggregator. The aggregator aggregates and encrypts the data with the shared secret key of the sink and forwards it to the sink. The set of nodes is reselected with new set of authentication keys in the second round of aggregation. By simulation results, we demonstrate that the proposed technique resolves the security threat of node capture attacks. | Wireless Sensor Network (WSN) consists of number of distributed autonomous sensors spatially, that has many applications. These are often used in potentially adverse as well as in hostile environment. Hence security is an important factor during communication. There are three critical issues for wireless sensor networks such as network lifetime, saving energy and security. A sensor node has limited battery power so need effective key distribution and management mechanism for secure communication. Enormous key distribution and management mechanism have been proposed in research literatures. Here, we provide a survey of various key management schemes in WSNs and made an extensive study to categorize available key management techniques and analyze the possible network security on them. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 23,552 |
Currently, wireless radio frequency (RF) communication and Wireless Sensor Network (WSN) has shifted its trend on human or item tracking capability to real time monitoring capability especially in healthcare industry. Monitoring patient's condition is one of the crucial tasks in any hospital to ensure patients are in good and stable condition. Efforts have been made by many researchers to use WSN to measure temperature, heart rate, oxygen saturation, respiratory rate and etc. to monitor patient's condition remotely in hospitals. This research focuses on integrating a temperature sensor to a wireless transceiver Zigbee network and is used to measure patient's body temperature from remote location (nurse's workstation. Few thermistor temperature sensors were used to determine reliability and their reading were compared against thermometer and the one with an accurate and stable reading was chosen. Zigbee network or accurately known as IEEE 802.15.4/Zigbee is known to be a low power consumption device with better transmission range, higher network flexibility and large number of nodes. Through the experimentation, Zigbee network is proven capable to provide stability in data transmission at longer range at different temperature environment. | The IEEE 802.15.4e standard has four different superframe structures for different applications. Use of a low latency deterministic network (LLDN) superframe for the wireless sensor network is one of them, which can operate in a star topology. In this paper, a new channel access mechanism for IEEE 802.15.4e-based LLDN shared slots is proposed, and analytical models are designed based on this channel access mechanism. A prediction model is designed to estimate the possible number of retransmission slots based on the number of failed transmissions. Performance analysis in terms of data transmission reliability, delay, throughput and energy consumption are provided based on our proposed designs. Our designs are validated for simulation and analytical results, and it is observed that the simulation results well match with the analytical ones. Besides, our designs are compared with the IEEE 802.15.4 MAC mechanism, and it is shown that ours outperforms in terms of throughput, energy consumption, delay and reliability. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 23,553 |
Dedicated with appreciation to Klaus Krickeberg on his 80th birthday. "There is probably no more legitimate use of the instrument of statistics than its application to the study of epidemic diseases." Arthur Ransome (1868) | Data/content dissemination among the mobile devices is the fundamental building block for all the applications in wireless mobile collaborative computing, known as mobile peer-to-peer. Different parameters such as node density, scheduling among neighboring nodes, mobility pattern, and node speed have a tremendous impact on data diffusion in a mobile peer-to-peer environment. In this paper, we develop analytical models for object diffusion time/delay in a wireless mobile network to apprehend the complex interrelationship among these different parameters. In the analysis, we calculate the probabilities of transmitting a single object from one node to multiple nodes using the epidemic model of spread of disease. We also incorporate the impact of node mobility, radio range, and node density in the networks into the analysis. Utilizing these transition probabilities, we estimate the expected delay for diffusing an object to the entire network both for single object and multiple object scenarios. We then calculate the transmission probabilities of multiple objects among the nodes in the wireless mobile network considering network dynamics. Through extensive simulations, we demonstrate that the proposed scheme is efficient for data diffusion in the wireless mobile network. Copyright © 2012 John Wiley & Sons, Ltd. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 23,554 |
In this paper, we present a method for approximating the values of sensors in a wireless sensor network based on time series forecasting. More specifically, our approach relies on autoregressive models built at each sensor to predict local readings. Nodes transmit these local models to a sink node, which uses them to predict sensor values without directly communicating with sensors. When needed, nodes send information about outlier readings and model updates to the sink. We show that this approach can dramatically reduce the amount of communication required to monitor the readings of all sensors in a network, and demonstrate that our approach provides provably-correct, user-controllable error bounds on the predicted values of each sensor. | Wireless sensor networks have enormous potential to aid data collection in a number of areas, such as environmental and wildlife research. In this paper, we address the challenges of supporting many-to-many aggregation in a sensor network. An application of many-to-many aggregation is in-network control of sensors. For expensive sensing tasks such as sap flux measurements and camera repositioning, we use low-cost information obtained at multiple other nodes in the network to control such tasks, e.g., decreasing sampling rates when readings are predictable or unimportant, while increasing sampling rates when there are interesting activities. In general, there is a many-to-many relationship between sources (nodes providing control inputs) and destinations (nodes requiring control outputs). We present a method for implementing many-to-many aggregation in a sensor network that minimizes the communication cost by optimally balancing a combination of multicast and in-network aggregation. Our optimization technique is efficient in finding the initial solution and handling dynamic updates. | Australia's remarkable economic performance during the 1990s has not resulted in a significant convergence of real per capita income, output, and employment levels across the country's states and territories. This paper explores the role of certain economic rigidities that may have contributed to the lack of convergence, including rigidities in labor markets and in the structure of federal government transfers to households and subnational governments. The analysis suggests that the wage awards system has restricted the adjustment of real wages to productivity differentials, thus contributing to higher unemployment rates in some states. Federal government transfers to households also appear to have adversely affected work incentives in high unemployment states by limiting participation in the labor force. | eng_Latn | 23,555 |
MANETs are widely used to communicate with each other wireless devices via bidirectional wireless links either directly or indirectly and these functionalities are performed by collection of mobile nodes equipped with both wireless transmitter and a receiver. However, the open medium and wide distribution of nodes make MANET vulnerable to malicious attackers. In this case, it is crucial to develop efficient intrusion-detection mechanisms to protect MANET from attacks. To overcome this problem a new approach for intrusion-detection system named Enhanced Adaptive Acknowledgment (EAACK) is proposed for MANETs. Compared to contemporary approaches, EAACK demonstrates higher malicious-behavior-detection rates in certain circumstances while does not greatly affect the network performances. | MANETs have unique characteristics like dynamic topology, wireless radio medium, limited resources and lack of centralized administration, as a result, they are vulnerable to different types of attacks in different layers of protocol stack. Each node in a MANET is capable of acting as a router. Routing is one of the aspects having various security concerns. In this paper, we will present survey of common Denial-of-Service (DoS) attacks on network layer namely Wormhole attack, Black hole attack and Gray hole attack which are serious threats for MANETs. We will also discuss some proposed solutions to detect and prevent these attacks. As MANETs are widely used in many vital applications, lots of research work has to be done to find efficient solutions against these DoS attacks that can work for different routing protocols. | Purpose ::: The aim of this study was to determine whether high keV monoenergetic reconstruction of dual energy computed tomography (DECT) could be used to overcome the effects of beam hardening artefact that arise from preferential deflection of low energy photons. | eng_Latn | 23,556 |
Ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (AdoMetDC) are two key enzymes in polyamine biosynthesis. Both the ODC and the AdoMetDC gene is regulated by androgens in accessory sex organs of mice and rats, whereas only the ODC gene is androgen-responsive in rodent kidney. Androgenic responses in murine and rat kidneys are, however, dissimilar in that the induction of ODC activity and ODC mRNA accumulation is transient in the rat but sustained in the murine renal cells. In addition, in situ hybridization experiments with single-stranded cRNA probes revealed that ODC gene expression occurs in different subpopulations of epithelial cells of the proximal tubules in mice and rats. ODC and AdoMetDC genes are androgen-regulated in the same cell types of the accessory sex organs, as judged by hybridization histochemistry. Sequencing of the promotor region of the murine ODC gene has indicated the presence of several DNA elements for binding of transcription factors/regulatory proteins, including a putative androgen-response element at about 900 nucleotides upstream of the transcription start site. | Ornithine decarboxylase (ODC) is a key enzyme in polyamine biosynthesis. Increased polyamine levels are required for growth, differentiation, and transformation of cells. In situ detection of ODC in cells and tissues has been performed with biochemical, enzyme cytochemical, immunocytochemical, and in situ hybridization techniques. Different localization patterns at the cellular level have been described, depending on the type of cells or tissues studied. These patterns varied from exclusively cytoplasmic to both cytoplasmic and nuclear. These discrepancies can be partially explained by the (lack of) sensitivity and/or specificity of the methods used, but it is more likely that (sub)cellular localization of ODC is cell type-specific and/or depends on the physiological status (growth, differentiation, malignant transformation, apoptosis) of cells. Intracellular translocation of ODC may be a prerequisite for its regulation and function. | Wireless sensor networks (WSNs) are more likely to be distributed asynchronous systems. In this paper, we investigate the achievable data collection capacity of realistic distributed asynchronous WSNs. Our main contributions include five aspects. First, to avoid data transmission interference, we derive an R o -proper carrier-sensing range (R o - PCR) under the generalized physical interference model, where R o is the satisfied threshold of data receiving rate. Taking R o - PCR as its carrier-sensing range, any sensor node can initiate a data transmission with a guaranteed data receiving rate. Second, based on R o - PCR, we propose a Distributed Data Collection (DDC) algorithm with fairness consideration. Theoretical analysis of DDC surprisingly shows that its achievable network capacity is order-optimal and independent of network size. Thus, DDC is scalable. Third, we discuss how to apply R o - PCR to the distributed data aggregation problem and propose a Distributed Data Aggregation (DDA) algorithm. The delay performance of DDA is also analyzed. Fourth, to be more general, we study the delay and capacity of DDC and DDA under the Poisson node distribution model. The analysis demonstrates that DDC is also scalable and order-optimal under the Poisson distribution model. Finally, we conduct extensive simulations to validate the performance of DDC and DDA. | eng_Latn | 23,557 |
With the tremendous growth in data traffic, the wireless industry is evolving towards new technologies. Recent advances in technology have provides portable computers with wireless interfaces that allow networked communication even while a user is mobile. Wireless networking greatly enhances the utility of a portable computing device. It allows mobile users to communicate with other users with much more flexibility. Mobile IP (1) is a proposed standard of the Internet Engineering Task Force (IETF) designed to support mobile users. It allows a mobile computer to be reachable at a fixed IP address (called its home address) irrespective of its current point of attachment to the Internet. Mobile IP is a mobility support protocol that supports roaming across multiple Access Points without having to re-establish the end to end connection. In this paper, we take the position that despite several challenges that Mobile IP faces, it would turn out to be the protocol for supporting mobility in the future. In this paper, the implementation of mobile IP in wireless networks, the motivation for Mobile IP, the basics of the protocol, and the relationship of Mobile IP with other protocols is discussed. After the protocol overview, the challenges in Mobile IP, the current developments involving Mobile IP (including mobility for IP version 6) and the current state of standardization of Mobile IP is discussed. | As required by [RFC 1264], this report discusses the applicability of Mobile IP to provide host mobility in the Internet. In particular, this document describes the key features of Mobile IP and shows how the requirements for advancement to Proposed Standard RFC have been satisfied. | As required by [RFC 1264], this report discusses the applicability of Mobile IP to provide host mobility in the Internet. In particular, this document describes the key features of Mobile IP and shows how the requirements for advancement to Proposed Standard RFC have been satisfied. | eng_Latn | 23,558 |
In this paper we discuss a scheme that allows sensor networks to operate securely and efficiently. In this scheme after deployment the sensors go through a self-organization phase when they establish a communication pattern among themselves; then they follow this pattern through multiple activity phases when they collect, process, and transmit information. The algorithm for self-organization assumes anonymous sensors and random times of the communication events, as well as random communication frequencies; the sensors use random number generators and a set of shared seeds so no external entity can either join in, or predict the time when the sensors in the set will transmit and attempt to interfere with the transmissions. The scheme extends the lifetime of the network by reducing the power consumption; it minimizes the number of collisions experienced by a sensor when it transmits and maximizes the time a sensor is either idle or dedicated to monitoring and/or internal data processing. | In this paper we develop a new multiaccess protocol for ad hoc radio networks. The protocol is based on the original MACA protocol with the adition of a separate signalling channel. The unique feature of our protocol is that it conserves battery power at nodes by intelligently powering off nodes that are not actively transmitting or receiving packets. The manner in which nodes power themselves off does not influence the delay or throughput characteristics of our protocol. We illustrate the power conserving behavior of PAMAS via extensive simulations performed over ad hoc networks containing 10-20 nodes. Our results indicate that power savings of between 10% and 70% are attainable in most systems. Finally, we discuss how the idea of power awareness can be built into other multiaccess protocols as well. | This paper presents two novel generic adaptive batching schemes for replicated servers. Both schemes are oblivious to the underlying communication protocols. Our novel schemes adapt their batching levels automatically and immediately according to the current communication load. This is done without any explicit monitoring or calibration of the system. Additionally, the paper includes a detailed performance evaluation. | eng_Latn | 23,559 |
The amorphous multi-connected networks have e-merged as a new trend to meet the fast increasing wireless capacity and coverage demands of future 5G networks. To realize such amorphous networks, ultra dense network (UDN) technology is expected as a promising candidate for its flexible network architecture and abundant radio resources. Yet, the multi-connection optimization for UDN is still left as an open problem nowadays. This motivates us to explore how many and which access points (APs) should be accessed in multi-connected amorphous UDNs. To solve this problem, we introduce a new definition of the maximum number of accessed APs for help, and propose two algorithms to identify this number and handle the AP selection respectively. Monte Carlo simulations testify the validity of our scheme and prove that our strategy can guarantee the soft handover and overcome the “ping-pong effect” efficiently in various kinds of networks with high sum-rate performance. | Demands for very high system capacity and end-user data rates of the order of 10 Gb/s can be met in localized environments by Ultra-Dense Networks (UDN), characterized as networks with very short inter-site distances capable of ensuring low interference levels during communications. UDNs are expected to operate in the millimeter-wave band, where wide bandwidth signals needed for such high data rates can be designed, and will rely on high-gain beamforming to mitigate path loss and ensure low interference. The dense deployment of infrastructure nodes will make traditional wire-based backhaul provisioning challenging. Wireless self-backhauling over multiple hops is proposed to enhance flexibility in deployment. A description of the architecture and a concept based on separation of mobility, radio resource coordination among multiple nodes, and data plane handling, as well as on integration with wide-area networks, is introduced. A simulation of a multi-node office environment is used to demonstrate the performance of wireless self-backhauling at various loads. | Ulmus davidiana Nakai (UDN) has been used for a long time to cure inflammation in oriental medicine. To evaluate the cytoprotective effects of the UDN glycoprotein, we measured cytotoxicity, the level of intracellular reactive oxygen species (ROS), activity of nuclear factor-kappaB (NF-kappaB), nitric oxide (NO) production, and thiobarbituric acid-reactive substances (TBARS) formation in 12-O-tetradecanoylphorbol 13-acetate (TPA)-treated BNL CL.2 cells. In TPA-treated BNL CL.2 cells, the results showed that UDN glycoprotein has dose-dependent blocking activities against TPA-induced cytotoxicity and NF-kappaB activation. In cytotoxic-related events, UDN glycoprotein (200 microg/ml) has an inhibitory effect on intracellular ROS production, NO production, and TBARS formation, without any toxic effects in the BNL CL.2 cells. These results suggest that UDN glycoprotein has cytoprotective abilities against TPA-induced oxidative cell injury. | eng_Latn | 23,560 |
In this paper, we present a new scheme for dynamic adaptation of transmission power and contention window (CW) size to enhance performance of information dissemination in Vehicular Ad-hoc Networks (VANETs). The proposed scheme incorporates the Enhanced Distributed Channel Access (EDCA) mechanism of 802.11e and uses a joint approach to adapt transmission power at the physical (PHY) layer and quality-of-service (QoS) parameters at the medium access control (MAC) layer. In our scheme, transmission power is adapted based on the estimated local vehicle density to change the transmission range dynamically, while the CW size is adapted according to the instantaneous collision rate to enable service differentiation. In the interest of promoting timely propagation of information, VANET advisories are prioritized according to their urgency and the EDCA mechanism is employed for their dissemination. The performance of the proposed joint adaptation scheme was evaluated using the ns-2 simulator with added EDCA support. Extensive simulations have demonstrated that our scheme features significantly better throughput and lower average end-to-end delay compared with a similar scheme with static parameters. | This research proposes the use of the evolutionary algorithm NSGA II (Non-dominated Sorting Genetic Algorithm II) to optimize parameters in the MAC-layer in search of the best throughput, latency and packet loss values, in an urban scenario. This approach showed a 90% reduction in the time needed to find the best MAC-layer configurations for multi objective optimization of throughput, latency and packet loss, when comparing to an exhaustive search. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 23,561 |
This article presents Mobile Encounter Networks, which emerge when mobile devices come across each other and form a temporary connection between them using a common short-range radio technology. Local information exchanges between mobile devices results in a broadcast diffusion of information to other users of the network with a delay. In addition to presenting the concept of mobile encounter networks, we also provide an abstract method for describing the information diffusion process inside them. | In the performance evaluation of a protocol for an ad hoc network, the protocol should be tested under realistic conditions including, but not limited to, a sensible transmission range, limited buffer space for the storage of messages, representative data traffic models, and realistic movements of the mobile users (i.e., a mobility model). This paper is a survey of mobility models that are used in the simulations of ad hoc networks. We describe several mobility models that represent mobile nodes whose movements are independent of each other (i.e., entity mobility models) and several mobility models that represent mobile nodes whose movements are dependent on each other (i.e., group mobility models). The goal of this paper is to present a number of mobility models in order to offer researchers more informed choices when they are deciding upon a mobility model to use in their performance evaluations. Lastly, we present simulation results that illustrate the importance of choosing a mobility model in the simulation of an ad hoc network protocol. Specifically, we illustrate how the performance results of an ad hoc network protocol drastically change as a result of changing the mobility model simulated. | Adolescent penetration into the labor market is a relatively new, and much understudied, phenomena. To date, limited empirical evidence suggests that the extensive employment of adolescents increases their offending. We bring together insights garnered from life-course criminology, which emphasizes the timing of transitional role changes; and economic sociology, which draws attention to the "social embeddedness" of development and decision-making. The objective is to test whether a youth's embeddedness within the labor market has deleterious consequences for the youth's behavior. Our results show that work embeddedness is positively related to delinquency, and that this effect is not accounted for by prior levels of delinquent involvement. These findings were replicated by use of a community sample. In total our findings suggest that being embedded in a work role as a teenager has general deleterious consequences for behavior. | eng_Latn | 23,562 |
Internet of Things promises large scale interconnected sensing and actuation capabilities in domains, areas, applications and activities never accessed before by Internet. Besides other technical barriers, wireless network node lifetime impedes its applicability. To reduce the energy cost incurred by wireless communication, several existing mechanisms typically downscale the power of transmitters. However, this increases the instability of the link and aggravates the hidden-node terminal and energy-hole problems. In this work, we assess the effect of transmission power on the performance of a low-power wireless network. Both MAC and routing signaling are taken into account to estimate a more realistic impact of power scaling in the energy efficiency of a network. Our experiments in various settings demonstrate a high cost of low transmission power in terms of both duty cycle and collisions. Symmetrically, high transmission power ensures higher PDR and energy efficiency in a network with multiple source nodes and CCA enabled. | Preserving energy is a very critical issue in mobile ad-hoc sensor networks (MASNETs) because sensor nodes have a severe resource constraints due to their lack of processing power and limited in power supply. Since the communication is the most energy consuming activities in MASNETs, the power use for transmission or reception of packet should be managed as much as possible. One way to reduce energy consumption is by applying transmission power control (TPC) technique to adjust the transmission power in communication between nodes. This technique has been widely studied in MASNETs. However, as MASNET applications emerge, the unique characteristics of this network such as severe resource constraints and frequent topology change suggest that TPC might be useful to reduce energy consumption in MASNETs. Therefore, we investigate different effects of TPC on Ad hoc On-Demand Distance Vector (AODV) routing protocols for MASNETs. AODV is used as a medium of communication to assist the investigation of the effects of TPC in multihop communication in this networks with Random Way Point (RWP) mobility model. Our simulation results show a noticeable effects of TPC implementation technique on MASNETs in respect to transmission energy consumption and packet received ratio at low node mobility. These results support the use of TPC technique to enhance the performance of multihop AODV routing protocol in MASNETs. | These studies were undertaken to examine the effect of aging on low density lipoprotein (LDL) metabolism in the male hamster. When the hamsters were maintained on a low-cholesterol, low-triglyceride diet, rates of LDL transport in the various tissues of the body and plasma LDL-cholesterol concentrations remained constant over the entire life span (1-24 months) of the hamster. In contrast, rates of de novo cholesterol synthesis fell 50-97% in the various tissues of the body during the transition from rapid body growth in the young animal to the stable adult size. Thus, changes in tissue requirements for cholesterol over the life span of these animals were met by an appropriate adjustment in the rate of de novo synthesis rather than by alterations in LDL transport. When animals were fed a diet enriched in cholesterol and saturated triglycerides, rates of LDL production increased, total body LDL receptor activity was suppressed, and plasma LDL-cholesterol levels rose. Older animals, however, were not more susceptible than young animals to the detrimental effects of these dietary fats. These studies support the view that aging per se has not effect on LDL transport by the liver or other tissues. Rather, the progressive rise in plasma LDL-cholesterol levels seen in Western man is likely due to the consumption of a diet enriched in cholesterol and saturated triglyceride which increases the LDL-cholesterol production rate and suppresses receptor-dependent LDL transport. | eng_Latn | 23,563 |
In the future sensor nodes will either have GPS capabilities, or be able to run localization protocols in order to get an accurate estimation of their position. These features would make geographic convergecasting a feasible and promising solution for WSNs. Key for the actual implementation of WSNs is the design of cross-layer solutions which consider explicitly the resource constraints of sensor nodes, especially in terms of available energy, limited memory and processing capabilities. We present a new protocol, named ALBA (Adaptive-Load Balanced Algorithm), which uses a cross-layer approach, pursuing the following goals: i) ALBA minimizes the number of hops required to reach the sink through a geographic forwarding scheme; ii) traffic is distributed evenly in the network, favoring nodes that are experiencing low congestion, while avoiding overloaded regions; iii) channel access efficiency is optimized through an adaptive back-to-back transmission of "bursts of packets" once a relay is selected, and iv) nodes are progressively made aware of routes to redirect the packets to the sink even when a connectivity hole occurs, i.e., when some nodes are not able to deliver packets to the sink because of lack of next-hop relay nodes closer to the sink. | The resource limited nature of WSNs requires that protocols implemented on these networks be energy-efficient, scalable and distributed. In this paper, we present a novel combined routing and MAC protocol. The protocol achieves energy efficiency by minimizing signaling overhead through stateless routing decisions that are made at the receiver rather than at the sender. The protocol depends on a source node advertising its RSSI to its neighbors, which then contend to become the receiver of the packet, by measuring their local optimality index, and map this into a timer value. More optimal nodes have smaller timer values and so respond before less optimal nodes. The proposed solution is assessed through simulations. Performance results show the advantages of the proposed solution when compared to RBF protocol, a recently proposed cross-layer approach with similar goal. Keywords— Wireless sensor networks, Cross-layer protocols, Energy conservation, Network life time, | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 23,564 |
Due to constraints inherent in RF systems, it is commonly agreed that collision detection is not feasible for CSMA-based wireless networks. However, by applying ideas from the busy-tone solution for hidden terminals and engineering together existing solutions for RF communications, we devise a simple method to reliably detect collisions for the wireless channel. We investigate the throughput gain delivered by CSMA/CD and its cross-layer designed version for multipacket-reception capable physical layers. We show that collision detection can help the system operate closer to its channel capacity. Our novel performance-improving protocols can be applied as beneficial extensions to the IEEE 802.11 wireless LAN standards | In this paper, we consider the random accessing of a single slotted channel by a large number of packet-transmitting, bursty users. We assume that feedback broadcasting is available where some different information, in addition to the information assumed by the Capetanakis, Gallager, Massey, etc., models, is included in the feedback. In particular, we assume that the existence of energy detectors permits the broadcasting of the number of collided packets within each collision slot, whenever this number is below a certain limit. We first consider this limit to be infinity, and then a finite small number. For the model considered, we propose and analyze a collision resolution protocol (CRAI), whose implementation is simple. For Poisson input traffic and infinite number of energy detectors, we found that the CRAI is stable for input rates below 0.53237. For finite number of energy detectors, we propose a modified version of the CRAI (MCRAI). We found that the MCRAI reaches the throughput 0.53237, through the utilization of only about eight energy detectors. These protocols, like the ones introduced by Capetanakis, Gallager, Massey, etc., have good delay properties. | MLL1 regulates circadian promoters by depositing H3K4 trimethyl marks, whose levels are also modulated by the NAD+-dependent deacetylase SIRT1. SIRT1 is now shown to promote circadian deacetylation of MLL1, thus affecting MLL1's methyltransferase activity. | eng_Latn | 23,565 |
A tool designed to perform quality assurance on IPTV encoded assets is presented. The tool works on stored MPEG-2 transport stream files and combines a powerful graphical-user-interface with automatic no-reference detectors to handle video quality, audio and field-ordering issues. The tool provides automatic quality assurance of assets before they are made available for streaming and replaces the need for exhaustive viewing tests by human operators. | Internet Protocol TV (IPTV), an emerging Internet application, provides more flexibility and interactivity for users because of its embedded return channel. Wireless 802.11 networks, used as the last hop of IPTV networks, would add another dimension of mobility, which is of great value for hot spot deployment and is increasingly required for in-home content distribution. However, a wireless channel may suffer from multi-path fading and interference, which may cause random and burst packet loss and impact users' quality of experience of an IPTV program. We report the design, implementation and evaluation of merged hybrid adaptive FEC and ARQ (MHARQ) system for IPTV multicast over wireless LANs. In MHARQ, an IPTV cache server is introduced to improve the reliability for the last hop wireless distribution. MHARQ combines the advantages of receiver-driven staggered FEC and hybrid ARQ schemes to compensate the large dynamic range of WLAN channels and to achieve high reliability, scalability and wireless bandwidth efficiency for IPTV multicast. We also address backward compatible FEC encoding and decoding, audio and video synchronization issues in practical system implementation. Using the ORBIT radio grid test bed, we have investigated the performance of the proposed MHARQ system with various numbers of users per AP and different numbers of APs per IPTV cache server. It is demonstrated via real system implementation on ORBIT that MHARQ improves wireless bandwidth efficiency and scalability for reliable IPTV multicast, compared with existing reliable multicast schemes. | Perfect Quantum Cloning Machines (QCM) would allow to use quantum nonlocality for arbitrary fast signaling. However perfect QCM cannot exist. We derive a bound on the fidelity of QCM compatible with the no-signaling constraint. This bound equals the fidelity of the Bu\v{z}ek-Hillery QCM. | eng_Latn | 23,566 |
Crude β-glucan content in the medicinal mushroom Chaga (Inonotus obliquus) was measured by different extraction and analytical methods, and the results were compared. The alkali extraction (AE) method or enzymatic digestion (ED) method followed by a gravimetric analysis was employed to determine the crude β-glucan content. The amount of crude β-glucan in Chaga obtained by either AE or ED was 13.7 g/100 g or 15.3 g/100 g of the sample, respectively. Crude β-glucan content of Chaga obtained by the above preparation methods were corrected by chemical composition analysis and HPLC analysis. After composition analysis, the amounts of β-glucan measured in the 100 g Chaga samples were corrected to 10.1 g for ED and 10.7 g for AE method. β-glucan contents calculated by the amount of glucose in the HPLC analysis were 8.3 g/100 g and 8.1 g/100 g for ED and AE preparation methods, respectively. Although extraction method did not affect β-glucan content in Chaga as indicated by no significant difference (P>0.05) between extraction method, significant differences (P<0.05) were noted between the correction methods. The discrepancies of the result indicate a need for standardization of analytical method for β-glucan measurement in Chaga | Cancer is a leading cause of death worldwide. Recently, the demand for more effective and safer therapeutic agents for the chemoprevention of human cancer has increased. As a white rot fungus, Inonotus obliquus is valued as an edible and medicinal resource. Chemical investigations have shown that I. obliquus produces a diverse range of secondary metabolites, including phenolic compounds, melanins, and lanostane-type triterpenoids. Among these are active components for antioxidant, antitumoral, and antiviral activities and for improving human immunity against infection of pathogenic microbes. Importantly, their anticancer activities have become a hot recently, but with relatively little knowledge of their modes of action. Some compounds extracted from I. obliquus arrest cancer cells in the G0/G1 phase and then induce cell apoptosis or differentiation, whereas some examples directly participate in the cell apoptosis pathway. In other cases, polysaccharides from I. obliquus can indirectly be involved in anticancer processes mainly via stimulating the immune system. Furthermore, the antioxidative ability of I. obliquus extracts can prevent generation of cancer cells. In this review, we highlight recent findings regarding mechanisms underlying the anticancer influence of I. obliquus, to provide a comprehensive landscape view of the actions of this mushroom in preventing cancer. | In ad-hoc networks, where a user can enter, leave or move inside the network with no need for prior configuration, the support of multimedia applications that require very high bit-rates, is a challenging problem. Here, a centralized ad-hoc network architecture (CANA) is proposed, capable of efficiently supporting those applications in low mobility environments, while at the same time a standard wireless LAN environment is maintained for fast moving users. CANA is based on an enhanced HiperLAN/2 protocol architecture [ETR0230002 V0.2.0, 1999-04] [Johnsson, M., 1999], (even though this is not mandatory) that supports a dual mode of operation at 5 GHz and 60 GHz. In this system architecture, several ad-hoc specific functionalities are included, such as neighborhood discovery, clustering and routing. Among them, switching between different modes of operation has a large impact on the achievable performance of CANA. | eng_Latn | 23,567 |
The intrusion detection application in a homogeneous wireless sensor network is defined as a mechanism to detect unauthorized intrusions or anomalous moving attackers in a field of interest. The quality of deterministic sensor nodes deployment can be determined sufficiently by a rigorous analysis before the deployment. However, when random deployment is required, determining the deployment quality becomes challenging. ::: An area may require that multiple nodes monitor each point from the sensing area; this constraint is known as k-coverage where k is the number of nodes. The deployment quality of sensor nodes depends directly on node density and sensing range; mainly a random sensor nodes deployment is required. The major question is centred around the problem of network coverage, how can we guarantee that each point of the sensing area is covered by the required number of sensor nodes and what a sufficient condition to guarantee the network coverage? To deal with this, probabilistic intrusion detection models are adopted, called single/multi-sensing detection, and the deployment quality issue is surveyed and analysed in terms of coverage. We evaluate the capability of our probabilistic model in homogeneous wireless sensor network, in terms of sensing range, node density, and intrusion distance. | Wireless communication between sensors allows the formation of flexible sensor networks, which can be deployed rapidly over wide or inaccessible areas. However, the need to gather data from all sensors in the network imposes constraints on the distances between sensors. This survey describes the state of the art in techniques for determining the minimum density and optimal locations of relay nodes and ordinary sensors to ensure connectivity, subject to various degrees of uncertainty in the locations of the nodes. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 23,568 |
The modern research has found a variety of applications and systems with vastly varying requirements and characteristics in Wireless Sensor Networks (WSNs). The research has led to materialization of many application specific routing protocols which must be energy-efficient. As a consequence, it is becoming increasingly difficult to discuss the design issues requirements regarding hardware and software support. Implementation of efficient system in a multidisciplinary research such as WSNs is becoming very difficult. In this paper we discuss the design issues in hierarchical routing protocols for WSNs by considering its various dimensions and metrics such as Mobility, Power Usage, Traffic and Quality of Service. The paper presents a comprehensive comparative study for different hierarchical routing protocols for WSNs. | One of the recent trends in wireless networking is Wireless sensor network (WSN), in this type of network tiny electronic device sensors organized in an environment where human intervention is problematic. In WSN, various sensors organized in a sensing environment works together in coordination to monitor and control the physical property of an environment. To efficiently perform the given task while keeping the longer network lifetime, WSN requires Energy efficient routing protocol. In this paper two hierarchical routing protocols ECHERP (Equalized Cluster Head Election Routing Protocol) and PDCH (PEGASIS with Double Cluster head) has been discussed and performance of both the protocols is analyzed based on various QoS parameters like Delay, Throughput, Packet Drop Ratio and Energy consumption. | Wireless Sensor Networks (WSNs) are a new technology that has received a substantial attention from several academic research fields in the last years. There are many applications of WSNs, including environmental monitoring, industrial automation, intelligent transportation systems, healthcare and wellbeing, smart energy, to mention a few. Courses have been introduced both at the PhD and at the Master levels. However, these existing courses focus on particular aspects of WSNs (Networking, or Signal Processing, or Embedded Software), whereas WSNs encompass disciplines traditionally separated in Electrical Engineering and Computer Sciences. This paper gives two original contributions: the essential knowledge that should be brought in a WSNs course is characterized, and a course structure with an harmonious holistic approach is proposed. A method based on both theory and experiments is illustrated for the design of this course, whereby the students have hands-on to implement, understand, and develop in practice the implications of theoretical concepts. Theory and applications are thus considered all together. Ultimately, the objective of this paper is to design a new course, to use innovative hands-on experiments to illustrate the theoretical concepts in the course, to show that theoretical aspects are essential for the solution of real-life engineering WSNs problems, and finally to create a fun and interesting teaching and learning environments for WSNs. | eng_Latn | 23,569 |
Providing anonymity to routes in a wireless ad hoc network from passive eavesdroppers is considered. Using Shannon's equivocation as an information theoretic measure of anonymity, scheduling strategies are designed for wireless nodes using receiver directed signaling. The achievable rate region for multiaccess relays are characterized under constraints on average packet latency. The relationship between overall network throughput and the route anonymity is obtained by drawing a connection to the rate-distortion tradeoff in information theory. A decentralized implementation of the relaying strategy is proposed, and the corresponding performance analyzed. | Providing anonymous connection service in mobile ad hoc networks is a challenging task. In addition to security concerns, performance concerns must be addressed properly as well. Chaum's mix method (Comms. of the ACM, vol.24(2), p.84-88, 1981) can effectively thwart an adversary's attempt at tracing packet routes and can hide the source and/or destination of packets. However, applying the mix method in ad hoc networks may cause significant performance degradation due to its non-adaptive mix route selection algorithm. We propose a dynamic mix routing algorithm to find topology-dependent mix routes for anonymous connections. Its effectiveness in improving network performance is validated by simulation results. We also address the potential degradation of anonymity due to dynamic mix routing. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 23,570 |
We present a comparative delay analysis of tree-based reliable multicast protocols and show the influence of varying sending rates, group sizes, packet loss probabilities and branching factors of the control tree. Besides the average delivery delay we consider the delay to reliably deliver all packets and the round trip delay. The first two examine the delay between generation of a packet at the sender and correct reception at a randomly chosen receiver or all receivers, respectively. The latter is the delay between generation of a packet at the sender and reception of all acknowledgement packets at the sender. Our numerical results show that all tree-based protocols provide low delays and good scalability. From the four considered protocol classes, NAK-based protocols achieve the best scalability but ACK-based protocols achieve the lowest delays. | Multicast is an efficient communication technique to save bandwidth for group communication purposes. A number of protocols have been proposed in the past to provide a reliable multicast service. Briefly classified, they can be distinguished into sender-initiated, receiver-initiated and tree-based approaches. In this paper, an analytical bandwidth evaluation of generic reliable multicast protocols is presented. Of particular importance are new classes with aggregated acknowledgments. In contrast to other approaches, these classes provide reliability not only in case of message loss but also in case of node failures. Our analysis is based on a realistic system model, including data packet and control packet loss, asynchronous local clocks and imperfect scope-limited local groups. Our results show that hierarchical approaches are superior. They provide higher throughput as well as lower bandwidth consumption. Relating to protocols with aggregated acknowledgments, the analysis shows only little additional bandwidth overhead and therefore high throughput rates. | We monitored single-neuron activity in the orbitofrontal cortex of rats performing a time-discounting task in which the spatial location of the reward predicted whether the delay preceding reward delivery would be short or long. We found that rewards delivered after a short delay elicited a stronger neuronal response than those delivered after a long delay in most neurons. Activity in these neurons was not influenced by reward size when delays were held constant. This was also true for a minority of neurons that exhibited sustained increases in firing in anticipation of delayed reward. Thus, encoding of time-discounted rewards in orbitofrontal cortex is independent of the encoding of absolute reward value. These results are contrary to the proposal that orbitofrontal neurons signal the value of delayed rewards in a common currency and instead suggest alternative proposals for the role this region plays in guiding responses for delayed versus immediate rewards. | eng_Latn | 23,571 |
Vehicular Ad hoc Network (VANET) is a kind of mobile ad hoc network using the capabilities of wireless communication for Vehicle-to-Vehicle and Vehicle-to-Roadside communication to provide safety and comfort to vehicles in transportation system. People in vehicles want to access data of their interest from Road Side Unit (RSU). RSU need to schedule these requests in a way to maximize the service ratio. In this paper we have proposed new methods for careful analysis of incoming requests to find whether these requests can be completed within deadline or not and to provide dynamic service queue. Simulation results show that the proposed schemes increase the service ratio significantly. | This paper introduces a promising application over vehicular ad hoc networks (VANETs), where advertisers use VANETs to disseminate their commercial ads via car-to-car communication, targeting a large number of potential customers inside cars. However, due to the noncooperative behavior of selfish or even malicious nodes in real-world scenarios, such a vehicular advertisement system cannot be realized unless proper incentives and security mechanisms are in place. This paper presents signature-seeking drive (SSD), which is a secure incentive framework that stimulates cooperative dissemination of advertising messages among vehicular users in a secure way. Unlike existing incentive systems, SSD does not rely on tamper-proof hardware or game-theoretic approaches but leverages a public key infrastructure to provide secure incentives for cooperative nodes. With a set of ad dissemination designs proposed, we demonstrate that our SSD is robust in both incentive and security perspectives. | Vehicular ad hoc Network (VANET) are a class of ad hoc systems work to guarantee the safety and security of traffic. An important point in VANET is the manner by which to believe the data transmitted when the neighboring vehicles are quickly changing and moving all through range. The fundamental point of this paper is to distinguish Sybil attack in VANET. A two phase security based mechanism is proposed to give reliable solution in identifying and blocking the Sybil attacked nodes to secure the information and providing safety and trust on the application. In the first phase Public Key Infrastructure (PKI) is taken and in the second phase hash function is considered. In this way to defeat Sybil attack we can easily recognizing Sybil attacks in VANET with much accurate. | eng_Latn | 23,572 |
Aiming at the difficulty of deploying wireless sensor networks (WSNs) on three-dimensional (3D) surfaces, based on the grey wolf optimizer (GWO), an enhanced version of the grey wolf optimizer is proposed for deploying WSNs on 3D surfaces, namely the enhanced grey wolf optimizer (EGWO), which is characterized by enhanced exploitation and exploration ability of the algorithm. The novelty of EGWO is that the grey wolf population is divided into two parts, one part is responsible for the outer-layer encircle and the other is responsible for the inner-layer encircle, and the introduction of Tent mapping. The purpose of this is to enhance the exploitation and exploration ability of the algorithm respectively, so as to improve the convergence and optimization precision of the algorithm. In addition, in terms of WSN deployment in 3D surfaces, this paper improves the means of determining the perceived blind zone. Meanwhile, a novel method to calculate the WSNs coverage area of simple and complex 3D surfaces is presented by combining the grid and integral of the 3D surfaces. The EGWO is favorably compared with the GWO and three existing variants of the grey wolf optimizer when testing on 12 well-known benchmark functions. The simulation experiment results show that compared with the existing algorithms, EGWO can provide a very competitive search result in terms of optimization precision and convergence performance. Finally, this paper applies EGWO to the 3D surface deployment of WSN. Simulations show that compared with the other three deployment algorithms, EGWO can improve the network coverage of WSN, which can save network deployment costs. In addition, the probability of network connectivity deployed by EGWO is higher, that is, EGWO can provide a better deployment solution. | The sensor deployment problem of wireless sensor networks (WSNs) is a key issue in the researches and the applications of WSNs. Fewer works focus on the 3D autonomous deployment. Aimed at the problem of sensor deployment in three-dimensional spaces, the 3D self-deployment (3DSD) algorithm in mobile sensor networks is proposed. A 3D virtual force model is utilized in the 3DSD method. A negotiation tactic is introduced to ensure network connectivity, and a density control strategy is used to balance the node distribution. The proposed algorithm can fulfill the nodes autonomous deployment in 3D space with obstacles. Simulation results indicate that the deployment process of 3DSD is relatively rapid and the nodes are well distributed. Furthermore, the coverage ratio of 3DSD approximates the theoretical maximum value. | BACKGROUND ::: Obesity rates are recognized to be at epidemic levels throughout much of the world, posing significant threats to both the health and financial security of many nations. The causes of obesity can vary but are often complex and multifactorial, and while many contributing factors can be targeted for intervention, an understanding of where these interventions are needed is necessary in order to implement effective policy. This has prompted an interest in incorporating spatial context into the analysis and modeling of obesity determinants, especially through the use of geographically weighted regression (GWR). ::: ::: ::: METHOD ::: This paper provides a critical review of previous GWR models of obesogenic processes and then presents a novel application of multiscale (M)GWR using the Phoenix metropolitan area as a case study. ::: ::: ::: RESULTS ::: Though the MGWR model consumes more degrees of freedom than OLS, it consumes far fewer degrees of freedom than GWR, ultimately resulting in a more nuanced analysis that can incorporate spatial context but does not force every relationship to become local a priori. In addition, MGWR yields a lower AIC and AICc value than GWR and is also less prone to issues of multicollinearity. Consequently, MGWR is able to improve our understanding of the factors that influence obesity rates by providing determinant-specific spatial contexts. ::: ::: ::: CONCLUSION ::: The results show that a mix of global and local processes are able to best model obesity rates and that MGWR provides a richer yet more parsimonious quantitative representation of obesity rate determinants compared to both GWR and ordinary least squares. | eng_Latn | 23,573 |
Wireless Sensor Networks (WSNs) are increasingly used in different application fields thanks to several advantages such as cost-effectiveness, scalability, flexibility and self-organization. A hot research topic concerns the study of algorithms and mechanisms for reducing the power consumption of the nodes in order to maximize their lifetime. To this end, this paper proposes an approach based on two fuzzy controllers that determine the sleeping time and the transmission power. Simulation results reveal that the device lifetime is increased by 30% with respect to the use of fixed sleeping time and transmission power and by 25% with respect to a state-of-the-art work that adjusts only the sleeping time. | In wireless sensor network, it is essential to find effective means for power control of randomly distributed nodes. In this paper, based on diverse receiving QoS parameters, a fuzzy algorithm for peer to peer power control of wireless sensor nodes is proposed. Simulation results show that the proposed algorithm reduces packet error rate (PER) and prolongs survival time of network, compared with fixed transmission power method. Thus, this fuzzy algorithm could realize reliable data transmission with low power consumption. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 23,574 |
We propose a medium access control protocol for wireless sensor networks (WSN) called adaptive sensor medium access control (AMAC), which is based on the sensor medium access control (S-MAC) protocol. Since WSNs are energy constrained, the lifetime of the network must be increased by making it as energy efficient as possible. Whereas S-MAC uses a fixed duty cycle for sleeping, AMAC adapts to traffic conditions by incorporating multiple duty cycles. Under a high traffic load, AMAC has a short duty cycle and awakes more often. Under a low traffic load, AMAC has a longer duty cycle and awakes infrequently. The AMAC protocol is simulated in OPNET Modeler. Analysis indicates that AMAC uses 15% less power and 22% less energy cost per byte than S-MAC with a tradeoff in twice the latency. For an application insensitive to latency, the AMAC protocol offers an extended lifetime | In this paper we develop a new multiaccess protocol for ad hoc radio networks. The protocol is based on the original MACA protocol with the adition of a separate signalling channel. The unique feature of our protocol is that it conserves battery power at nodes by intelligently powering off nodes that are not actively transmitting or receiving packets. The manner in which nodes power themselves off does not influence the delay or throughput characteristics of our protocol. We illustrate the power conserving behavior of PAMAS via extensive simulations performed over ad hoc networks containing 10-20 nodes. Our results indicate that power savings of between 10% and 70% are attainable in most systems. Finally, we discuss how the idea of power awareness can be built into other multiaccess protocols as well. | This paper proposes S-MAC, a medium access control (MAC) protocol designed for wireless sensor networks. Wireless sensor networks use battery-operated computing and sensing devices. A network of these devices will collaborate for a common application such as environmental monitoring. We expect sensor networks to be deployed in an ad hoc fashion, with nodes remaining largely inactive for long time, but becoming suddenly active when something is detected. These characteristics of sensor networks and applications motivate a MAC that is different from traditional wireless MACs such as IEEE 802.11 in several ways: energy conservation and self-configuration are primary goals, while per-node fairness and latency are less important. S-MAC uses a few novel techniques to reduce energy consumption and support self-configuration. It enables low-duty-cycle operation in a multihop network. Nodes form virtual clusters based on common sleep schedules to reduce control overhead and enable traffic-adaptive wake-up. S-MAC uses in-channel signaling to avoid overhearing unnecessary traffic. Finally, S-MAC applies message passing to reduce contention latency for applications that require in-network data processing. The paper presents measurement results of S-MAC performance on a sample sensor node, the UC Berkeley Mote, and reveals fundamental tradeoffs on energy, latency and throughput. Results show that S-MAC obtains significant energy savings compared with an 802.11-like MAC without sleeping. | eng_Latn | 23,575 |
This paper introduces a new broadcast query (BQ) forwarding technique for multipath routing protocols that operate within wireless mobile ad-hoc networks (MANET). This technique increases the number of node disjoint routes created by up to 75% over standard broadcast forwarding strategies without causing any increase in the number of BQs forwarded. | In a multihop mobile ad hoc network, broadcasting is an elementary operation to support many applications. Previously, it is shown that naively broadcasting by flooding may cause serious redundancy, contention, and collision in the network, which we refer to as the broadcast storm problem. Several threshold-based schemes are shown to perform better than flooding in that work. However, how to choose thresholds also poses a dilemma between reachability and efficiency under different host densities. In this paper, we propose several adaptive schemes, which can dynamically adjust thresholds based on local connectivity information. Simulation results show that these adaptive schemes can offer better reachability as well as efficiency as compared to the previous results. | After extensive upgrading, our radio-frequency quadrupole (RFQ) linac is again installed on the accelerator test stand (ATS). The measured parameters of the RFQ, such as the output transverse emittance, transmitted beam, average energy, and energy spread is presented. | eng_Latn | 23,576 |
MANET i.e. a mobile ad hoc network does not have a fixed infrastructure and is a self configuring one. So the nodes are mobile and due to this mobility the uncertainty arises. This uncertainty affects the node's behavior and also choice of other nodes for proper communication with each other. The evaluation of the uncertainty is needed so that the less uncertain nodes can be considered for participating in the network communication. The uncertainty can be calculated using different theories namely probability, fuzzy theory, etc. The paper gives proposed possibility theory based on fuzzy basics mathematical model which is used to evaluate the uncertainty of the nodes. Also the proposed model is compared with the probability theory. The mathematical model is integrated in the AODV protocol with direct and indirect observation. Simulations are done under different varying parameters like number of malicious nodes and pause time. The result shows the effectiveness of proposed model in terms of throughput, packet delivery ratio and other metrics. | In MANET nodes help each other in data routing. MANET works well if the participating nodes cooperate with each other. It is impractical to assume that, all nodes participating in an open MANET are cooperative and honest. For individual nodes it may be benefcial to be non-cooperative and selfsh. However non-cooperation, selfshness and malicious behavior of the participating nodes may result into collapse of a MANET. Trust based routing algorithms aim to identify misbehaving and non-cooperating nodes in the MANET. These algorithms optimize the network performance by utilizing trustworthy nodes in effective way and penalizing non-cooperative nodes. This paper compares trust based and cryptographic approaches for implementing security in MANET routing. The paper discusses design issues in trust based routing protocols for MANET in details. The paper presents a survey on trust based routing protocols for MANET. The paper provides directions for future research in trust based routing for MANET. | We report enhancement of the mechanical stability of graphene through a one-step method to disperse gold nanoparticles on the pristine graphene without any added agent. | eng_Latn | 23,577 |
According to augmentation about interests for privacy in mobile network over the past few years, researches that provide the anonymity have been conducted in a number of applications. Ad hoc routing protocols with the provisions for anonymity both protect the privacy of nodes and also restrict the collection of network information by malicious nodes. Until recently, quite a number of anonymous routing protocols have been proposed. Many of them, however, do not make allowance for authentication. Thus, vulnerabilities such as modifications to packet data and denial of service attacks can be more easily exploited. In this paper, we propose the anonymous routing protocol also furnishing authentication in the mobile ad hoc network. This protocol supports these anonymity properties which should be provided in ad hoc network. In addition, authentication is also provided by group signature for both nodes and packets during route discovery phase. | Security issues have been emphasized when mobile ad hoc networks (MANETs) are employed into military and aerospace fields. In adv ersary environments, Anonymous communications are important for many applications of the mobile a d hoc networks (MANETs) deployed. A requirement on the network is to provide unidentifi ability and unlinkability for mobile nodes and thei r traffics. Eventhough a number of anonymous secure routing protocols have been proposed, the requirement is not fully satisfied. A new routing p rotocol, i.e., authenticated anonymous secure routing (AASR), to satisfy the requirement and defe nd the attacks is being proposed in this paper. The key-encrypted onion routing with a route secret ver ification message, is designed to prevent intermediate nodes from inferring a real destinatio n. Simulation results have demonstrated that the proposed Novel protocol is effective with improved performance when compared with the existing protocols. The salient feature of AASR is that when trust relationships in such among nodes, there is no need for a node to request and verify certificat es every time which reduces the computation overheads. Meanwhile, with neighbors' trust recommendations, a node can make objective judgement about another node's trust-worthiness to maintain t he whole system at a certain security level. | In this paper, we describe the applicaion of probabilistic models for indexing and retrieval with the TREC-2 collection. This database consists of about a million documents (2 gigabytes of data) and 100 queries (50 routing and 50 adhoc topics). For document indexing we use a description -oriented approach which exploits relevance data in order to produce a probabilistic indexing with single terms as well with phrases. With the adhoc queries, we present a new query term weighting method based on a training sample of other queries. For the routing queries, the RPI model is applied which combines probabilistic indexing with query term weighting based on query-specific feedback data. The experimental show very good performance for both types of queries | eng_Latn | 23,578 |
Wireless Body Area Network (WBAN) is a time critical remote network where various physiological information of patients are sent through satisfying stringent QoS requirements. However, performance of WBAN may degrade severely due to the coexistence problem, a well known phenomenon where different wireless channel access technologies share the overlapped frequency bands. In this paper, the coexistence problem of WBAN is addressed in terms of mutual interference mitigation and cross interference mitigation. A fuzzy logic based algorithm is proposed to detect the mutual interference and to mitigate it. Furthermore, a channel hopping technique is investigated to mitigate the cross interference problem. Simulation results show that our proposed techniques effectively mitigate the coexistence problem in WBAN scenarios. | Frequency channels are a scarce resource in the ISM bands used by IEEE 802.11 WLANs. Current radio resource management is often limited to a small number of non-overlapping channels, which leaves only three possible channels in the 2.4GHz band used in IEEE 802.11b/g networks. In this paper we study and quantify the effect of adjacent channel interference, which is caused by transmissions in partially overlapping channels. We propose a model that is able to determine under what circumstances the use of adjacent channels is justified. The model can also be used to assist different radio resource management mechanisms (e.g. transmitted power assignments) | Wireless body area network (WBAN) is an interesting application of sensor networks which can revolutionize our interaction with the outside world. WBAN like any other sensor network suffers limited energy resources and hence preserving the energy of the nodes is of great importance. Unlike typical sensor networks WBANs have few and dissimilar sensors. In addition, the body medium has its own propagation characteristic which means that the existing solution for preserving energy in wireless sensor networks might not be efficient in WBANs. The quality of the links between the nodes in WBAN is changing frequently due to the moving nature of the body. This can pose a major problem especially in the energy efficiency merit. In this work we have proposed an opportunistic scheme to exploit the body movements during the walking to increase the life time of the network. The results show that comparing to the existing methods this work can increase the life time of the network. | eng_Latn | 23,579 |
We introduce a time-limited neighbor detector service for mobile ad hoc networks, which enables a mobile device to detect other nearby devices in the past, present and up to some bounded time interval in the future. Our motivation lies in the emergence of a new trend of mobile applications known as proximity-based mobile applications, which enable a user to communicate with other users within some defined range and for a certain amount of time. Neighbor discovery is a fundamental requirement for these applications and is not restricted to the current neighbors but can include past or future neighbors. To implement the time-limited neighbor detector service, we apply an approach based on virtual mobile nodes. A virtual mobile node is an abstraction that is akin to a mobile node that travels in the network in a predefined trajectory. In practice it can be implemented by a set of mobile nodes based on a replicated state machine approach. In this paper, we assume that each node can accurately predict its own locations up to some bounded time interval in the future. Thus, we present a time-limited neighbor detector algorithm that uses a virtual mobile node that continuously travels in the network, collects the predicted locations of all nodes, performs the neighborhood matching between nodes and sends the list of neighbors to each node. We show that our algorithm correctly implements the time-limited neighbor detector service under a set of conditions. | This paper presents a new abstraction for virtual infrastructure in mobile ad hoc networks. An Autonomous Virtual Mobile Node (AVMN) is a robust and reliable entity that is designed to cope with the inherent difficulties caused by processors arriving, leaving, and moving according to their own agendas, as well as with failures and energy limitations. There are many types of applications that may make use of the AVMN infrastructure: tracking, supporting mobile users, or searching for energy sources.The AVMN extends the focal point abstraction in [9] and the virtual mobile node abstraction in [10]. The new abstraction is that of a virtual general-purpose computing entity, an automaton that can make autonomous on-line decisions concerning its own movement. We describe a self-stabilizing implementation of this new abstraction that is resilient to the chaotic behavior of the physical processors and provides automatic recovery from any corrupted state of the system. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 23,580 |
A mobile ad hoc network (MANET) is a self-organizing network of mobile nodes which can form a dynamic topology. All the nodes generally have a limited transmission range and move freely throughout the network. So implementing a good routing protocol to react the link state changing is a critical issue in current research. From now on, a popular method is introducing a link quality evaluation (LQE) mechanism in routing algorithm. In this paper, we study the link quality evaluation scheme based on traffic-based metrics, such as packet reception ratio (PRR), and find two flaws (one is the assessment lagging and the other is the sample bias) which result in large handoff delay in routing protocols, especially when the PRR-like scheme is used in mobile environments. Therefore, we propose a link quality prediction (LQP) model to sense the link state by analyzing the Signal to Noise ratio of the neighbor link, and using grey theory to tackle the small sample size problem. Finally we set up mobile nodes test-bed to validate the scheme. Based on comparison of previous schemes, the LQP's performance is far better in handoff delay and packet loss rate. | The ARP-Path protocol has flourished as a promise for wired networks, creating shortest paths with the simplicity of pure bridging and competing directly with TRILL and SPB. After analyzing different alternatives of ARP-Path and creating the All-Path family, the idea of migrating the protocol to wireless networks appeared to be a good alternative to protocols such as a AODV. In this article, we check the implications of adapting ARP-Path to a wireless environment, and we prove that good ideas for wired networks might not be directly applicable to wireless networks, as not only the media differs, but also the characterization of these networks varies. | The oxidative polymorphism of debrisoquine (DBQ) has been determined in 89 patients with colo-rectal cancer and in 556 normal control subjects. Four patients and 34 controls, with a metabolic ratio >12.6, were classified as poor metabolisers of DBQ (n.s.). | eng_Latn | 23,581 |
Mobile Ad hoc networks have no fixed infrastructure available for routing packets in an end to end network and instead rely on intermediary peers. There are various types of attacks which an effect the MANETs. Routing Protocols, data, bandwidth and battery power are the common target of these attacks. This paper gives an overview of various secure routing protocols by presenting their characteristics and functionality along with their respective merits and drawbacks. A comparison of these protocols is also presented based upon certain security parameters. | In Mobile Ad Hoc Network security plays an important role when data transmission is performed within un-trusted wireless environment. There are various kinds of attacks like Black Hole, White Hole, Gray Hole, Wormhole and many more have been identified & corresponding solution have been proposed. All these | MANETs have unique characteristics like dynamic topology, wireless radio medium, limited resources and lack of centralized administration, as a result, they are vulnerable to different types of attacks in different layers of protocol stack. Each node in a MANET is capable of acting as a router. Routing is one of the aspects having various security concerns. In this paper, we will present survey of common Denial-of-Service (DoS) attacks on network layer namely Wormhole attack, Black hole attack and Gray hole attack which are serious threats for MANETs. We will also discuss some proposed solutions to detect and prevent these attacks. As MANETs are widely used in many vital applications, lots of research work has to be done to find efficient solutions against these DoS attacks that can work for different routing protocols. | eng_Latn | 23,582 |
The increasing demand for real-time applications in WSN has raised the requirement of protocols considering both energy efficiency and end-to-end delay. A PSMis proposed in the IEEE 802.11 protocol to reduce the power consumptions of wireless nodes. Wireless nodes can stay in doze mode and periodically wake up to retrieve the frames buffered in the APs. However, the 802.11 PSM is not such energy efficiency for WSN. First, in the process of the node's transmitting polling frames to AP, channel contentions may cause sensor nodes to deplete power quickly. Second, the mechanism of retrieving buffered frames can be inefficient since a polling frame is able to pick up only one data frame. Third, a prioritized service for urgent needs is not supported. In this paper, we propose a prioritized reservation scheme to enhance the IEEE 802.11 PSM. The concept of PSCW is suggested, during which PSM sensor nodes can retrieve the buffered frames using the reserved SPs, where the priorities of the PSM nodes are considered in scheduling the SPs. Through analytic models and discrete simulations, we show that our proposed mechanism outperforms the existing PSM schemes in terms of energy efficiency and prioritized services. | In wireless local area networks (WLANs), power conservation for mobile devices is considered as one of the most important issues because it effectively prolongs the battery life of mobile devices. The IEEE 802.11 standard specifies a power-saving mode that allows mobile nodes to adaptively operate in sleep and wake modes to reduce the overall energy consumption. In the IEEE 802.11 power-saving mode, the access point (AP) can adjust the number of nodes in wake mode at every beacon interval. In this paper, we first investigate how the number of nodes in wake mode affects both energy consumption and delay performance in WLANs. We then propose a balanced power-saving strategy, which determines an appropriate number of nodes in wake mode based on a trade-off between energy consumption and packet delay. Through a performance analysis and extensive simulations, we show that our proposed scheme effectively reduces overall energy consumption while retaining low packet delay. | Blind image super-resolution reconstruction is one of the hot and difficult problem in image processing. a framework of blind single-image super-resolution reconstruction algorithm is proposed. In the low-resolution imaging model, the processes of motion blur, down-sampling, and noise are considered. The parameter of motion blur is estimated through an error-parameter analysis method. Utilizing Wiener filtering image restoration algorithm, an error-parameter curve at different motion distance is generated, from which the motion distance of the motion point spread function (PSF) can be estimated approximately. The super-resolution image is reconstructed through the iterative back projection (IBP) algorithm. The experimental results show that motion PSF estimation plays an important role on the quality of the SR reconstructed image, and also demonstrate the effectiveness of the proposed algorithm. | eng_Latn | 23,583 |
Black hole attack is a common security issue encountered in Mobile Adhoc Network (MANet) routing protocol. In this paper a trust value for each node has been obtained depending upon the packet forwarding ability of the node. A rank is generated based on this trust value. In the route discovery step of the AODV routing protocol a path is chosen in such a way that more trusted nodes are involved. Also a node can be excluded which is not trusted from the route. Thus the packet is transferred through a more trusted path rather than the shortest path. Results of simulation through the use of OMNeT++ simulation software shows that higher threshold values gives less packet drops providing more reliable communication. | Mobile Ad-hoc Networks is a group of mobile nodes that are connected dynamically, in which each node acts as a router to all other nodes. Due to the absence of centralized administration and dynamic nature, MANETs are vulnerable to various kinds of attacks from malicious nodes. Several secure routing protocols like AODV, DSR, TSR, and OLSR have been used in MANET for transmission of data. In MANET, we are using trust based QoS aware routing protocol for identifying the malicious nodes in the network. Trust is mandatory in routing for transmission of data securely. Hence trust models, trust computation is implemented in the routing protocols. In this paper, survey of several trusts based and QoS aware routing protocol is performed. In this review paper, the study of different trust based and QoS aware AODV protocols that are using trusted infrastructure and trust models is performed for preventing the attacks and misbehavior from malicious nodes in the network. The performance of trust based routing protocol has been analyzed that helps to work efficiently and can be used in various applications of MANETs for improving the security performance of the network. | Wireless sensor networks have been widely used in many different applications and in the future they will play an increasingly important role. Since these networks have no fixed infrastructure and are usually distributed over large areas, the use of routing protocols is indispensable. However, when the number of nodes within an area increases, the communication interferences and collisions increase significantly, thus reducing the network performance. In this paper, we first introduce a new measurable quantity, the "node concentration", in contrast to the standard network density. Then, the performance of the AODV (Ad-hoc On-demand Distance Vector) routing protocol is evaluated with respect to the variation in node concentration. Finally, we propose an enhancement of AODV, called CG-AODV, by introducing a "node concentration-driven gossiping" approach for limiting the flooding of control packets. The simulation results demonstrate that CG-AODV provides significant improvements in terms of packet delivery ratio and path discovery delay. | eng_Latn | 23,584 |
In view of the various quality of service (QoS) requirements raised by the different applications of vehicular ad hoc networks (VANETs), the characteristic of communication capacity is vital for the design and implement of the Intelligent Transportation System (ITS). Although some scaling law-based results had already been obtained for VANETs to describe the general performance changing pattern when the total number of network nodes goes to infinity, they cannot be used directly to estimate the actual capacity of a communication pair or the entire network. To make up with this disadvantage, a interference-based capacity analysis is finished in this paper for the VANETs scenario. For representing the unique constraint of inter-vehicle distance, which directly affects both the signal and interference power decaying, the car-following model is used to describe the vehicles' mobility feature. Based on that, a series of probability characteristics are derived for a general interfering scenario, which finally leads to the expected VANET capacity. We believe the new results obtained in this paper will provide useful guidelines for the deployment of future VANETs. | A particular class of vehicular networks is the one that includes off-the-shelf end-user equipment (e.g., laptops and PDAs) running from the interior of vehicles: in-car nodes. They are subject to limited communication conditions when compared with nodes specifically designed to this context. Existing works either consider antennas installed on top of the vehicle roof or nodes that operate in infrastructure mode. In this article, we investigate through real experiments the characteristics of links formed by in-car nodes running off-the-shelf wireless technologies such as IEEE 802.11(a/g) in ad hoc mode. We surprisingly observe that in-car nodes do show enough performance in terms of network capacity to be used in a number of applications, such as file transfer in peer-to-peer applications. Nonetheless, we identify some key performance issues and devise a number of configuration recommendations and future work directions. | Vehicular ad hoc Network (VANET) are a class of ad hoc systems work to guarantee the safety and security of traffic. An important point in VANET is the manner by which to believe the data transmitted when the neighboring vehicles are quickly changing and moving all through range. The fundamental point of this paper is to distinguish Sybil attack in VANET. A two phase security based mechanism is proposed to give reliable solution in identifying and blocking the Sybil attacked nodes to secure the information and providing safety and trust on the application. In the first phase Public Key Infrastructure (PKI) is taken and in the second phase hash function is considered. In this way to defeat Sybil attack we can easily recognizing Sybil attacks in VANET with much accurate. | eng_Latn | 23,585 |
Communication comprises the most power consuming operation that a sensor node performs. In this work we present a topology reduction algorithm and perform pre-deployment simulations of a senor network and analyze the initial topology for possibility of links reduction. The alternative link-reduced topologies are analyzed and compared against the initial topology regarding the overall number of links in the network, the number of neighbors and the possibility for transmission power reduction. Furthermore, a calculative estimation of the power consumption and respective node lifetime, from a communication perspective, is provided. | In this article we present the main results obtained in the ARTEMIS-JU WSN-DPCM project between October 2011 and September 2015. The first objective of the project was the development of an integrated toolset for Wireless sensor networks (WSN) application planning, development, commissioning and maintenance, which aims to support application domain experts, with limited WSN expertise, to efficiently develop WSN applications from planning to lifetime maintenance. The toolset is made of three main tools: one for planning, one for application development and simulation (which can include hardware nodes), and one for network commissioning and lifetime maintenance. The tools are integrated in a single platform which promotes software reuse by automatically selecting suitable library components for application synthesis and the abstraction of the underlying architecture through the use of a middleware layer. The second objective of the project was to test the effectiveness of the toolset for the development of two case studies in different domains, one for detecting the occupancy state of parking lots and one for monitoring air concentration of harmful gasses near an industrial site. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 23,586 |
In [1] a family of DHT-based infrastructures, termed DKS (N, k, f), with a number of desirable properties is presented. In the current paper, we show how multicast is achieved in DKS (N, k, f) overlay networks. Each multicast group is represented by an instance of DKS (N, k, f), which is created and maintained exactly as the underlying overlay network. Multicast messages are efficiently disseminated thanks to a correcting broadcast algorithm that allow each multicast message to be delivered exactly once to all application layer proccesses despite the presence of erroneous routing information. | This paper presents Scribe, a scalable application-level multicast infrastructure. Scribe supports large numbers of groups, with a potentially large number of members per group. Scribe is built on top of Pastry, a generic peer-to-peer object location and routing substrate overlayed on the Internet, and leverages Pastry's reliability, self-organization, and locality properties. Pastry is used to create and manage groups and to build efficient multicast trees for the dissemination of messages to each group. Scribe provides best-effort reliability guarantees, and we outline how an application can extend Scribe to provide stronger reliability. Simulation results, based on a realistic network topology model, show that Scribe scales across a wide range of groups and group sizes. Also, it balances the load on the nodes while achieving acceptable delay and link stress when compared with Internet protocol multicast. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 23,587 |
Multi-hop broadcast schemes are commonly used by safety applications to disseminate urgent messages in vehicular ad hoc networks. Sender-based schemes can effectively decrease the collisions caused by simultaneous transmissions among different candidate forwarders and speed up the whole broadcast progress by piggy-backing extra control information in the broadcast message to candidate forwarders. However, the construction and delivery of control information are usually of high cost. In this letter, we present a novel sender-based broadcast protocol for vehicular ad hoc networks. An index-based control structure is proposed for the definition of the control information. A segment-based partition algorithm, which is adaptive to the distribution of forwarder candidates, is proposed to minimize the size of the control information. Simulation results show that the proposed scheme can achieve faster broadcast than other existing sender-based schemes. | We study the effect of radio signal shadowing dynamics, caused by vehicles and by buildings, on the performance of beaconing protocols in Inter-Vehicular Communication (IVC). Recent research indicates that beaconing, i.e., one hop message broadcast, shows excellent characteristics and can outperform other communication approaches for both safety and efficiency applications, which require low latency and wide area information dissemination, respectively. We show how shadowing dynamics of moving obstacles hurt IVC, reducing the performance of beaconing protocols. At the same time, shadowing also limits the risk of overloading the wireless channel. To the best of our knowledge, this is the first study identifying the problems and resulting possibilities of such dynamic radio shadowing. We demonstrate how these challenges and opportunities can be taken into account and outline a novel approach to dynamic beaconing. It provides low-latency communication (i.e., very short beaconing intervals), while ensuring not to overload the wireless channel. The presented simulation results substantiate our theoretical considerations. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 23,588 |
An proficient data routing protocol is significant in such networks for elevation in terms of network capacity and scalability. Hybrid wireless networks conjoining the recompenses of both mobile ad-hoc networks and arrangement wireless networks have been getting augmented consideration due to their ultra-high recital. Conversely, most routing protocols for these networks merely cartel the ad-hoc transmission mode with the cellular transmission mode, which receives the hitches of ad-hoc transmission. A Distributed Three-hop Routing Protocol to upsurge throughput and makes full routine of pervasive base station in Hybrid Wireless Networks presents a Distributed Three-hop Routing protocol (DTR) for hybrid wireless networks. DTR divides a message data stream into segments and transmits the segments in a distributed manner and makes full spatial reuse of a system via its high speed ad-hoc interface and relieves mobile gateway congestion via its cellular interface. Additionally, sending segments to a number of base stations simultaneously increases throughput and makes full use of widespread base stations. DTR significantly reduces overhead due to short path lengths and the elimination of route discovery and maintenance. DTR also has a congestion control algorithm to avoid overloading base stations. | ODMA is a multi-hop relaying routing protocol, the use of which has been investigated in conventional cellular scenarios. This paper compares the performance of ODMA with direct transmission for cases where links may be required directly to other nodes, as well as to a controlling (backbone) node. For an interference-limited system, it is shown that whereas the topology is not supportable by a conventional (single-hop) system, a relayed system is able to provide service. A new admission control and routing algorithm based on receiver interference is presented which is shown to further enhance performance. | Distillation at an infinite reflux ratio in combination with an infinite number of trays has been investigated. | eng_Latn | 23,589 |
Specific congestion control mechanisms for wireless vehicular communications have been studied extensively in previous research. Various mechanisms with important functionality for a scalable vehicular communications system design have been identified, and their applicability for certain communications scenarios has been studied in the past. Definition of overall resource utilization principles for guiding functional specification and complementary design of congestion control tools has been a missing aspect of previous research. This paper proposes a suitable scalability principle for each major vehicular communication scenario: periodic safety broadcasts, event-driven safety broadcasts, and unicast message forwarding. Each scenario section investigates an appropriate design of individual congestion control tools for the implementation of related scalability principle. It is then described how individual tools shall complement one another. | Wireless vehicular communications are attracting more and more interests for applied research in industries. Most of the efforts are spent in deploying Vehicular Mobile Ad-Hoc Networks (VANETs) for applications such as active safety and Internet services. This paper addresses routing problem in VANETs for applications related to comfort and infotainment for users where an unicast routing protocol optimized for fast topology changes is needed. In previous research work, we have proposed a new movement prediction-based routing concept for VANETs called MOPR which we have already applied to the reactive routing protocol AODV in order to improve its performances by exploiting vehicules movements patterns. In this work, we first propose a new design of this concept, then we apply it to the OLSR routing protocol by optimizing the procedure of selecting the MPR (Multipoint Relay) sets as well as that of determining the optimal path from each pair of vehicles. Basically, the connected MPR graph is composed of the most stable wireless links in the VANETs. We conduct several simulation scenarios to investigate the performance of the modified OLSR (OLSR-MOPR) by studying several metrics including the end-to-end average delay, the routing overhead, the packet delivery ratio, and the routing overhead ratio. The simulation results of the modified OLSR for various VANETs scenarios show great improvements comparing to the basic OLSR. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 23,590 |
Reliability is a big challenge to any wireless transmission as wireless networks tend to drop a large proportion of frames due to channel errors. To improve reliability over the noisy wireless channels, forward error correction (FEC) schemes can be employed for wireless networks. Static and adaptable FEC algorithms can improve or degrade the performance of the wireless networks if their overheads are not matched properly to the underlying channel error, especially when the path loss fluctuates widely. This paper provides a new approach of alleviating the problem from a pure medium access control (MAC) centric perspective. The new MAC protocol, called cooperative MAC (CMAC) enhances the existing IEEE 802.11e wireless local area network (WLAN) MAC protocol by introducing spatial diversity which is provided via user cooperation. We prove that this protocol greatly enhances the robustness of the WLAN operation. Additionally we compare the performance of CMAC protocol with the direct and multi-hop transmissions. | This paper proposes an opportunistic rate-adaptive expected transmission time (ORETT) metric, which exploits cooperative (relay-aided) retransmissions to achieve high-throughput routing in multi-rate wireless mesh networks. This metric captures the combined effects of MAC-layer cooperative retransmission by neighbor nodes with transmission rate diversity (and rate-dependent link quality). In our approach, a relay node is selected among one-hop neighbors to assist with packet retransmissions and minimize the expected retransmission time. The paper describes the design and implementation of the ORETT routing metric using the DSR routing protocol. Our extensive simulation on the Qualnet platform confirms that multi-rate routing using ORETT significantly reduces the overall transmission time while yielding higher packet delivery ratio compared to single rate unicast or non-cooperative ETT based routing. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 23,591 |
High-speed wireless computing networks are now economically feasible for home users, via 802.11b wireless protocols and their associated hardware. Such centralized "point-to-multipoint" installations typically allow a range of about 100 meters from the central access point. It is possible to use the same network protocols and hardware to construct a "wireless mesh" or "multipoint-to-multipoint" network in which any connected node can communicate directly or indirectly with any other connected node. The research project described in this article applies wireless mesh networking to inter-vehicular communication. Three vehicles were connected as a wireless mesh network using laptop computers with 802.11b radio cards and mesh networking software. The vehicles were then driven on a highway in Northern California to collect data about network connectivity. The goal of the experiment was to prove that such a network could be quickly and easily constructed and that network connectivity could be maintained under normal driving conditions. Data was collected on network connectivity and time delay of network packet transmission. | Vehicular communication system is a key part of intelligent transportation system (ITS) while vehicle safety communication (VSC) is a major target of vehicular communication. The use of radio frequency identification (RFID) system for vehicular communication has been proposed for pedestrian-safety. In this paper, an extended RFID system and infrastructure for vehicle safety communication through co-operative routing of information on vehicles' sudden motion and direction changes and warning messages for post-accident scenarios is proposed. It also provides a demonstration on the structure of warning codes and flow of information within the system and the vehicular ad-hoc network (VANET) for the vehicle safety. This paper also includes the simulation results for line-of-sight (LOS) communication and a special non-line-of-sight communication (NLOS) to observe the co-operative distance covered by co-operative routing and the related bit error rates (BERs). Doppler shift effect is also considered in the simulation. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 23,592 |
In the Wireless Local Area Networks (WLANs), the terminals are often powered by battery, so the power-saving performance of the wireless network card is a very important issue. For IEEE 802.11 Ad hoc networks, a power-saving scheme is presented in Medium Access Control (MAC) layer to reduce the power consumption by allowing the nodes enter into the sleep mode, but the scheme is based on Time-Drive Scheme (TDS) whose power-saving efficiency becomes lower and lower with the network load increasing. This paper presented a novel energy-saving mechanism, called as Hybrid-Drive Scheme (HDS), which introduces into a Message-Drive Scheme (MDS) and combines MDS with the conventional TDS. The MDS could obtain high efficiency when the load is heavy; meanwhile the TDS has high efficiency when the network load is small. The analysis shows that the proposed HDS could obtain high energy-efficiency whether the network load is light or heavy and have higher energy-saving efficiency than conventional scheme in the IEEE 802.11 standard. | This paper presents an optimization of the power saving mechanism in the Distributed Coordination Function (DCF) in the IEEE 802.11 standard. In the IEEE 802.11 power saving mode specified for DCF, time is divided into so-called beacon intervals. At the start of each beacon interval, each node in the power saving mode periodically wakes up for a duration called the ATIM window. The nodes are required to be synchronized to ensure that all nodes wake up at the same time. During the ATIM window, the nodes exchange control packets to determine whether they need to stay awake for the rest of the beacon interval. The size of the ATIM window has a significant impact on energy saving and throughput achieved by the nodes. This paper proposes an adaptive mechanism to dynamically choose a suitable ATIM window size. We also allow the nodes to stay awake for only a fraction of the beacon interval following the ATIM window. On the other hand, IEEE 802.11 DCF mode requires the nodes to stay awake either for the entire beacon interval following the ATIM window or none at all. Simulation results show that the proposed approach outperforms the IEEE 802.11 power saving mechanism in terms of throughput and the amount of energy consumed. | The Toyota Prius equipped with the Toyota Hybrid System (THS) II vehicle uses a combination of a combustion engine and two electric machines in order to increase the efficiency and the fuel economy. The Energy Management Strategy (EMS) of the THS II is analyzed using measurement data collected with a Toyota Prius under different driving conditions on the road and compared with an optimized EMS based on simulations. The main goal of this paper is to verify the control strategy as implemented in the Prius by comparing the measured strategy with an optimized strategy based on Energy Consumption Minimization Strategy (ECMS). The differences between the simulation results and the actual measured strategy are analysed and discussed. | eng_Latn | 23,593 |
Multiple sensor nodes are required to gather the information and exchange the information in the direction of the sink node which makes a network. The static common node (NC) deployment has been work towards the coverage of deterministic territory. At that point, the coordinates of each regular node have been determined with the assistance of geometry of coverage locale. Among those basic nodes, on the off chance that one of the nodes gets fail, at that point, the coverage hole is made. To solve this issue, a viable alternate node (NA) deployment method has been presented for supplanting the damaged node. And furthermore developed quadrant based neighbor to sink and neighbor to source (Q-(NS)2) routing protocol for lessening the superfluous flooding of ‘RREQ’ message to the majority of its neighbor while route discovery. A viable comparison has been done between this other node deployment procedure and references. The performance comparison has been done between Quadrant based Direct routing protocol (Q-DIR), Angle routing protocol (ARP) and Q-(NS)2 routing protocol. Therefore, Q-(NS)2 routing protocol decreases the pointless flooding of ‘RREQ’ to the greater part of its neighbor which implies it devours less energy for data packet delivery and no redundant node in NA deployment. | Deterministic deployment issue is different from most cases in wireless sensor network. To find a solution for limited number of sensor nodes in known area, this article proposed a new method to attain minimum nodes and maximum detection probability. Based on a more realistic detection method, this article adapts Delaunay Triangulation method to deploy new nodes according to their importance. A scoring mechanism is also designed to choose the proper candidate position. According to the simulation result, the proposed deployment algorithm owns good performance and flexibility. | The oxidative polymorphism of debrisoquine (DBQ) has been determined in 89 patients with colo-rectal cancer and in 556 normal control subjects. Four patients and 34 controls, with a metabolic ratio >12.6, were classified as poor metabolisers of DBQ (n.s.). | eng_Latn | 23,594 |
VANETs are distributed and self organizing communication networks built up from travelling vehicles. In this research, we have considered controlled latency process by managing the time span between updates for fault tolerance and finding alternative route for vehicles. Delay shown in proposed work is very less than shown in previous techniques due to time management in alternative route selection concept in vehicular adhoc network. | In VANET communication is one of the important concepts. Vehicular communication is defined as the conversation between two vehicles. Conservation in between the vehicles makes an accident free domain. As the pristine technologies are evolved and pristine applications emerging, so new fault tolerance methods are needed. In this technology many faults are arises due to mobility, software and hardware failures. To vanquish such type of faults this paper presents “Fault tolerance in VANET's”. The main goal of this paper is to detect and recovery the faults by using detectors and choose best nodes through which information can be transferred. The proposed model is simulated in NS-2 simulator to examine the potency of this scheme. To evaluate the performance of the proposed system some of the parameters considered are throughput, packet delivery ratio and packet drop. | Vehicular ad hoc Network (VANET) are a class of ad hoc systems work to guarantee the safety and security of traffic. An important point in VANET is the manner by which to believe the data transmitted when the neighboring vehicles are quickly changing and moving all through range. The fundamental point of this paper is to distinguish Sybil attack in VANET. A two phase security based mechanism is proposed to give reliable solution in identifying and blocking the Sybil attacked nodes to secure the information and providing safety and trust on the application. In the first phase Public Key Infrastructure (PKI) is taken and in the second phase hash function is considered. In this way to defeat Sybil attack we can easily recognizing Sybil attacks in VANET with much accurate. | eng_Latn | 23,595 |
Many clustering schemes have been proposed for different ad hoc networks and play an important role in self organizing them. A systematic classification of these clustering schemes enables one to better understand and make improvements. This paper surveys clustering schemes and classifies them into ad hoc sensor network clustering schemes and mobile ad hoc network clustering schemes. In sensor networks, the energy stored in the network nodes is limited and usually infeasible to recharge; the clustering schemes for these networks therefore aim at maximizing the energy efficiency. In mobile ad hoc networks, the movement of the network nodes may quickly change the topology resulting in the increase of the overhead message in topology maintenance; the clustering schemes for mobile ad hoc networks therefore aim at handling topology maintenance, managing node movement or reducing overhead | The wireless sensor ::: network (WSN) is one of the budding exploring areas and fast rising fields in ::: wireless communications. The sensor nodes in the network are generally ::: small-size, low-cost, low-power and multi-function capabilities. Wireless ::: sensor networks (WSNs) are used for various applications; since numerous sensor ::: nodes are usually deployed on remote and inaccessible places, the employment ::: and preservation should be easy and scalable. Sensor nodes in the field being ::: run out of energy quickly has been an issue and many energy efficient routing ::: protocols have been proposed to solve this problem and preserve the long life ::: of the network. This paper work proposes a hierarchical based node activation ::: routing technique which shows energy efficiency. This technique selects cluster ::: head with highest residual energy in each communication round of transmission ::: to the base station from the cluster heads. Hierarchical based node activation ::: routing technique with different levels of hierarchy simulation results ::: prolongs the lifetime of the network compared to other clustering schemes and ::: communication rounds of simulation increase significantly. | In Mobile Ad Hoc Network security plays an important role when data transmission is performed within un-trusted wireless environment. There are various kinds of attacks like Black Hole, White Hole, Gray Hole, Wormhole and many more have been identified & corresponding solution have been proposed. All these | eng_Latn | 23,596 |
In video surveillance with resource-constrained devices such as wireless video sensor nodes, power conservation, intrusion detection, and security are important features to guarantee. In this paper, we intend to preserve the network lifetime while fulfilling the surveillance application needs. We take into account security by considering that a malicious attacker can try to predict the behavior of the network prior to intrusion. These considerations lead to the definition of a novel chaos-based scheduling scheme for video surveillance. We explain why the chaos-based approach can defeat malicious intruders. Then, by simulations, we also compare our chaos-based scheduling to a classical random scheduling. Results show that in addition of being able to increase the whole network lifetime and to present comparable results against random attacks (low stealth time), our scheme is also able to withstand malicious attacks due to its fully unpredictable behavior. | Recently directional sensors have been widely deployed as they are more practicable under constraints of manufacture, size and cost. One common functionality of networks formed by such directional sensors is to monitor a set of discrete targets continuously. Large scale deployment makes sensor recharge impossible. By abundant deployment, it is reasonable and necessary to select subsets of sensors to operate alternatively so as to prolong the network lifetime. Such problem has been proved to be NP-Complete. This paper approximates network lifetime problem by randomized algorithm. Through constructing elementary sessions, which denotes active subset of sensors covering all targets, and linear programming, the approximating solution is derived within extremely less duration comparing to previous works. Simulation results demonstrate the algorithm's performance and sound explanation is also presented. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 23,597 |
We consider underwater multi-modal wireless sensor networks (UWSNs) suitable for applications on submarine surveillance and monitoring, where nodes offload data to a mobile autonomous underwater vehicle (AUV) via optical technology, and coordinate using acoustic communication. Sensed data are associated with a value, decaying in time. In this scenario, we address the problem of finding the path of the AUV so that the Value of Information (VoI) of the data delivered to a sink on the surface is maximized. We define a Greedy and Adaptive AUV Path-finding (GAAP) heuristic that drives the AUV to collect data from nodes depending on the VoI of their data. For benchmarking the performance of AUV path-finding heuristics, we define an integer linear programming (ILP) formulation that accurately models the considered scenario, deriving a path that drives the AUV to collect and deliver data with the maximum VoI. In our experiments GAAP consistently delivers more than 80 percent of the theoretical maximum VoI determined by the ILP model. We also compare the performance of GAAP with that of other strategies for driving the AUV among sensing nodes, namely, random paths, TSP-based paths and a “lawn mower”-like strategy. Our results show that GAAP always outperforms every other heuristic in terms of delivered VoI, also obtaining higher energy efficiency. | This short paper presents an adaptive cross-layer routing protocol for Underwater Acoustic Networks (UANs). The proposed solution, termed NADIR for Network Aware aDaptIve Routing, is fully distributed and self-adaptive. It supports the use of multiple coded modulation schemes and the usage of crosslayer information to interact with the physical layer. Link quality information is exploited along with energy and topological data in order to select the relay node to use. The protocol performance has been evaluated considering a challenging networking scenario, i.e., a polar environment, with very long propagation delays and a high probability of packet errors. The results show that the use of an adaptive strategy offers better network performance in terms of packet delivery and energy consumption in the presence of unreliable channels. | Blunt trauma abdomen rarely leads to gastrointestinal injury in children and isolated gastric rupture is even rarer presentation. We are reporting a case of isolated gastric rupture after fall from height in a three year old male child. | eng_Latn | 23,598 |
This paper provides a general framework to model and optimize lifetime maximization problems in wireless sensor networks with sensors having specialized capabilities like the ability to adjust their sensing range, change their directions, etc. In order to identify the set of tasks that a sensor carries out, the concept of role is introduced. These roles include sensor direction, sensing range, communication mode and combinations of these. The purpose is to identify schedules, represented as the allocation of roles to the sensors and a time interval for assuming such roles, while covering targets and transmitting signals to the base station. To do so, a large scale linear programming model is proposed and solved through an exact approach based on column generation, which is complemented with a branch-and-cut procedure used to address the pricing subproblem. The proposed approach is tested on an extensive set of randomly generated instances used to evaluate its performance. Computational results show the potential of the proposed approach for medium-large size instances for which it is possible to compute either the optimal or good quality solutions in short computational times. | Static sink-based wireless sensor networks (WSNs) suffer from an energy-hole problem. This incurs as the rate of energy consumption on sensor nodes around sinks and on critical paths is considerably faster. State-of-the-art en-routing filtering schemes save energy by countering false report injection attacks. In addition to their unique limitations, these schemes generally do not examine energy awareness in underlying routing. Mostly, these security methods are based on a fixed filtering capacity, unable to respond to changes in attack intensity. Therefore, these limitations cause network partition(s), exhibiting adverse effects on network lifetime. Extending network lifetime while preserving energy and security thus becomes an interesting challenge. In this article, we address the aforesaid shortcomings with the proposed adaptive en-route filtering (AEF) scheme. In energy-aware routing, the fitness function, which is used to select forwarding nodes, considers residual energy and other factors as opposed to distance only. In pre-deterministic key distribution, keys are distributed based on the consideration of having paths with a different number of verification nodes. This, consequently, permits us to have multiple paths with different security levels that can be exploited to counter different attack intensities. Taken together, the integration of the special fitness function with the new key distribution approach enables the AEF to adapt the underlying dynamic network conditions. The simulation experiments under different settings show significant improvements in network lifetime. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 23,599 |
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