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A Novel Scheme for Type-II Hybrid ARQ Protocols Using LDPC Codes | In this paper, we propose a novel type-II hybrid ARQ scheme using low density parity check (LDPC) codes. The proposed approach combines low hardware overhead with good decoding performance by using an efficient decoder operating at a much higher rate with a much smaller size parity check matrix. Our scheme makes parts of the previously received data gradually improved until successful decoding of the entire original codeword. We also present a novel efficient framework for constructing rate-compatible LDPC codes applied in our hybrid ARQ scheme. The progressive edge growth (PEG) construction method with zigzag pattern results in linear-time encoding. | Abstract A new discrete two-by-two matrix spectral problem with two potentials is introduced, followed by a hierarchy of integrable lattice equations obtained through discrete zero curvature equations. It is shown that the Hamiltonian structures of the resulting integrable lattice equations are established by virtue of the trace identity. Furthermore, based on a discrete four-by-four matrix spectral problem, the discrete integrable coupling systems of the resulting hierarchy are obtained. Then, with the variational identity, the Hamiltonian structures of the obtained integrable coupling systems are established. Finally, the resulting Hamiltonian systems are proved to be all Liouville integrable. | kor_Hang | 5,400 |
Study of DOA Joint Estimate Algorithms Based on Bis/multistatic | A new approach was proposed for the DOA joint estimation of signal,and the algorithms are based on ESPRIT and two or more array data correlation matrix.It estimated simultaneously the DOA of bis/multistatic.The algorithms estimated parameter are auto paired.The CRLB of the DOA stimation was also derived.The simulating results show that the new methods are equally effective. | A geometric approach in the design of codebooks for OR frequency-hopping multiple-access (FHMA) channels is developed by treating a signal matrix as a finite set of distinct points. The relationship among the parameters of an interference-free j-distinguishable-point codebook, j>or=1, is established by using coordinate-free arguments. Geometry induced by such a codebook is characterized, and the design of a well-structured j-distinguishable-point codebook is related to a block design problem. It is shown that a well-structured 1-distinguishable-point codebook implies the axiom system of a finite affine plane. > | eng_Latn | 5,401 |
A Multi-User Receiver for PUCCH LTE FORMAT 1 in Non-Cooperative Multi-Cell Architectures | In this paper, we propose a new multi-user receiver processing for PUCCH LTE that counteracts the ICI in a non-cooperative multi-cell architecture. Using the fact that the received signal in PUCCH signaling follows a constrained tensor model, a multi-user receiver based on an iterative joint channel/code estimation and symbol detection is proposed. The interest in such a challenging setting relies on the overhead reduction among neighboring cells. Simulation results show remarkable performance gains of the proposed receiver compared to the conventional time-frequency decorrelator based receiver under the same conditions. We also show a performance comparison with the cooperative version of such a tensor receiver. | Abstract This study contributes to the literature on socially responsible investing by examining the diversification potential of commodities, specifically oil, gold and clean energy together with the Brazilian Corporate Sustainability Index (ISE). Multivariate GARCH models are used to model volatility spillovers and conditional correlation in pairs of stocks containing ISE. Specifically, A-BEKK and A-DCC models with spillovers are estimated. The models’ results are used to compute and analyze the optimal weights and hedge ratios for stock portfolio holdings. The greatest benefit from diversification is obtained through the acquisition of gold and then OVX. | kor_Hang | 5,402 |
A novel diversity transmission technique using cooperative relay | In this paper, a novel diversity transmission technique using cooperative relay is presented. Although the conventional distributed space-time coded cooperative (DSTC) system achieves a diversity gain with single antenna user and relay, there is tradeoff between the diversity gain and resource requirements. Therefore, we propose a novel diversity transmission technique which can obtain diversity gain without additional time or frequency resources. From the performance evaluation, compared with the conventional method, the proposed method achieves 0.5 dB and 2.1 dB differences at BER=10−5 for QPSK and 16-QAM modulation, respectively. | Current algorithms for reader-writer synchronization do not scale for readers: readers cannot acquire locks in parallel. The authors describe two new algorithms that allow parallelism among readers during lock acquisition; this is achieved by distributing the lock state among different processors, and by trading reader throughput for writer throughput. Their experiments show that when reads are a large percentage of lock requests, the throughput of each of their algorithms scales significantly better than current algorithms. > | eng_Latn | 5,403 |
Re-transmission controlling method and wireless communication terminal apparatus | The invention relates to a variable support robust transform for multiple description coding. A multi-level transform generates descriptions containing compressed data that represents source data using a description generation operation and variable support filters for compaction at each level. The initial level filters the source data and each subsequent level operates on data filtered by a prior level. The description assignment and filtering at each level may vary to create different operating points for the multi-level transform. Each operating point may have a corresponding error recovery process. In one aspect, an error recovery process encodes additional descriptions that are combined with non-erroneous description data to provide error recovery of the data in missing or damaged descriptions. In another aspect, a multi-level transform is created by combining description generation and variable support filters at the various levels. | The problem of scaling down the size of the transmitting antenna of a solar power satellite is briefly discussed. It is shown that a multibeam Power Relay Satellite leads to smaller ground receiver stations which will improve the market penetration of power satellites. (WHK) | eng_Latn | 5,404 |
Channel Estimation and Uplink Achievable Rates in One-Bit Massive MIMO Systems | This paper considers channel estimation and achievable rates for the uplink of a massive multiple-input multiple-output (MIMO) system where the base station is equipped with one-bit analog-to-digital converters (ADCs). By rewriting the nonlinear one-bit quantization using a linear expression, we first derive a simple and insightful expression for the linear minimum mean-square-error (LMMSE) channel estimator. Then employing this channel estimator, we derive a closed-form expression for the lower bound of the achievable rate for the maximum ratio combiner (MRC) receiver. Numerical results are presented to verify our analysis and show that our proposed LMMSE channel estimator outperforms the near maximum likelihood (nML) estimator proposed previously. | Consider arbitrary collections A = a_1,a_2,.. .,a_n of items and Q = q_1,q_2,...,q_m (1 leqslant mn leqslant n) of queries from a totally ordered universe. The multiple rank problem involves computing for every query qi the number of items in A that have a lesser value. Our contribution is to show that the problem at hand can be solved time-optimally on meshes with multiple broadcasting. More specifically, if the collection A is siored in some order one item per processor and if Q is stored one query per processor in the leftmost frac{m} {{sqrt n }} columns of a mesh with multiple broadcasting of size sqrt n x /sqrt n, the corresponding instance of the multiple rank problem can be solved in Theta left( {m^{frac{1} {3}} n^{frac{1} {6}} } right) time. As an application we present a time-optimal algorithm to compute the histogram of a m-level gray image of size sqrt n x sqrt n in Theta left( {m^{frac{1} {3}} n^{frac{1} {6}} } right) time. | eng_Latn | 5,405 |
Differences in Paramedic Fatigue before and after Changing from a 24-hour to an 8-hour Shift Schedule: A Case Report. | AbstractEmergency medical services (EMS) clinicians often work 24-hour shifts. There is a growing body of literature, with an elevated level of concern among EMS leaders that longer shifts contribute to fatigued workers and negative safety outcomes. However, many questions remain about shift length, fatigue, and outcomes. We describe a case of a 26-year-old male paramedic who switched shift schedules during the midpoint of a randomized trial that addressed fatigue in EMS workers (clinicaltrials.gov identifier: NCT02063737). The participant (case) began the study working full-time with a critical care, advanced life support EMS system that utilized 24-hour shifts. He then transitioned to an EMS system that deploys workers on 8-hour shifts. Per protocol for the randomized trial, the participant completed a battery of sleep health and fatigue surveys at baseline and at the end of 90 days of study. He also reported perceived fatigue, sleepiness, and difficulty with concentration at the beginning, every 4 hour... | A multihop regenerative relay system is considered. We explore adaptive power allocation (PA) under a total power constraint to minimize the system error probability when the perfect channel state information (CSI) is known at the transmitters. We propose adaptive PA schemes with limited feedback when the transmitters have no perfect knowledge of CSI. Simulation results demonstrate the good performance of the proposed PA scheme with perfect CSI. When no perfect CSI is available at the transmitters, the proposed PA schemes with a small number of feedback bits are able to achieve very close performance to the adaptive PA with perfect CSI. | eng_Latn | 5,406 |
Assignment of EC Numbers to Enzymatic Reactions with MOLMAP Reaction Descriptors and Random Forests | The MOLMAP descriptor relies on a Kohonen SOM that defines types of covalent bonds on the basis of their physicochemical and topological properties. The MOLMAP descriptor of a molecule represents the types of bonds available in that molecule. The MOLMAP descriptor of a reaction is defined as the difference between the MOLMAPs of the products and the reactants and numerically encodes the pattern of changes in bonds during a chemical reaction. In this study, a genome-scale data set of enzymatic reactions available in the KEGG database was encoded by the MOLMAP descriptors and was explored for the assignment of the official EC number from the reaction equation with Random Forests as the machine learning algorithm. EC numbers were correctly assigned in 95%, 90%, and 85% (for independent test sets) at the class, subclass, and subsubclass EC number level, respectively, with training sets including one reaction from each available full EC number. Increasing differences between training and test sets were explore... | This paper considers channel estimation and achievable rates for the uplink of a massive multiple-input multiple-output (MIMO) system where the base station is equipped with one-bit analog-to-digital converters (ADCs). By rewriting the nonlinear one-bit quantization using a linear expression, we first derive a simple and insightful expression for the linear minimum mean-square-error (LMMSE) channel estimator. Then employing this channel estimator, we derive a closed-form expression for the lower bound of the achievable rate for the maximum ratio combiner (MRC) receiver. Numerical results are presented to verify our analysis and show that our proposed LMMSE channel estimator outperforms the near maximum likelihood (nML) estimator proposed previously. | eng_Latn | 5,407 |
Japanese business down-under : patterns of Japanese investment in Australia, 1957-1985 | Part I: Australia's Role in the Internationalistion of the Japanese Economy 1. Japanese Transnational Corporations: Motivations and Overseas Strategies 2. Japan, Australia and the Pacific Rim Part II: Japanese Business Activity in Australia, 1957-1985 3. Trading Companies 4. Manufacturing Companies 5. Banks and Financial Institutions Part III: Patterns and Implications 6. Patterns of Japanese Business Activity in Australia 7. Conclusions. | Abstract In this paper, we consider a multiple-input multiple-output (MIMO) cooperative communication system with single decode and forward (DF) relay. The system performance is analyzed by using joint antenna and path selection (JAPS) scheme over Nakagami-m fading channel. Then, we propose to use both JAPS and Sub-optimal transmit antenna selection strategy denoted by JAPS/maximum-ratio combining (JAPS/MRC) to improve the coding gain performance. For JAPS, a closed-form expression for the outage probability (OP) is derived. The upper bound of OP in high signal-to-noise ratio (SNR) regime is obtained. For JAPS/MRC a closed-form expression for the OP is also derived. The derived expressions are applicable with any number of antennas, different m i and distinct average SNRs between the paths. Simulation results are presented and show the validity of our theoretical analysis. | eng_Latn | 5,408 |
Erbium-ytterbium co-doped fiber amplifier with controlled 1060-nm Yb-ASE | In this work we present a new design of Er/Yb co-doped fiber amplifier with controlled amplified spontaneous emission ::: (ASE) at 1 μm. The Yb-ASE is controlled by stimulating a laser emission at 1064 nm in the amplifier, by providing ::: a positive 1 μm signal feedback loop. The results were discussed and compared to a conventional amplifier setup without ::: 1 μm ASE control. We have shown, that applying a 1064 nm signal loop in an Er/Yb amplifier can increase the output ::: power at 1550 nm and provide stable operation without parasitic lasing at 1 μm. | We present, by extension of some earlier results, the expression of an upper bound on the bit error rate (BER) of a digital communication system operating on a frequency selective channel linking N mobiles to an M/sup th/ order space diversity receiver using optimum combining and linear equalization. The bound is then used in conjunction with a Monte-Carlo simulation to emulate the time varying realizations of the channel and evaluate the corresponding outage rate. An explicit dependency of the performance bound on the system parameters is then obtained (using multipath Rayleigh fading model) together with its relationship with the so-called "optimum" bounds of the matched filter and information theoretic capacity types. Our results seem to indicate that, in general, such a linear equalization procedure falls short of exploiting the full potential of the time diversity coding gain available with such time dispersive channels. | eng_Latn | 5,409 |
Test of the Effectiveness of Hedging | FUTURES markets have been analyzed in two apparently different ways for the purpose of evaluating their efficiency for hedging purposes. The different approaches purport to reflect different concepts of hedging. The main objective of this article is to examine the relationship between the two testing procedures and to consider the adequacy of the tests in the light of the relevant concepts of hedging. | In this paper the least squares problem of signal estimation is introduced. The Code-Division Multiple Access (CDMA) signal model is transformed into a least squares minimization form. Based on the solutions of the problem, different receiver structures are derived. Channel estimation using least-squares method is also considered. The NMSE is used as a performance measure for the estimator. The performance of the different receivers is analyzed over AWGN channel. Performance over flat fading channel is also considered with and without channel estimation. The proposed receiver is modified to accommodate detection over frequency-selective fading channels with a least-squares channel estimator block. | eng_Latn | 5,410 |
Elementary Mathematics Resource Teacher Program. | Standardized test results over the years have shown that children in Philadelphia's inner-city public schools have been doing poorly in mathematics. In fact, the alarming statistics indicate that as the number of years a child spends in school increases, the child's success in achieving grade-level standards decreases. Concerning elementary mathematics in particular, there are some specific needs of inner-city children - | This paper considers channel estimation and achievable rates for the uplink of a massive multiple-input multiple-output (MIMO) system where the base station is equipped with one-bit analog-to-digital converters (ADCs). By rewriting the nonlinear one-bit quantization using a linear expression, we first derive a simple and insightful expression for the linear minimum mean-square-error (LMMSE) channel estimator. Then employing this channel estimator, we derive a closed-form expression for the lower bound of the achievable rate for the maximum ratio combiner (MRC) receiver. Numerical results are presented to verify our analysis and show that our proposed LMMSE channel estimator outperforms the near maximum likelihood (nML) estimator proposed previously. | kor_Hang | 5,411 |
Cutoff-cladding waveguides: Subdiffraction guided modes near cutoff | We propose a class of waveguides operating near cutoff such that electromagnetic energy is mainly bound to the cladding rather than the dielectric core to achieve subdiffraction confinement of light. The cladding incorporates an alternating stack of thin films that exhibit uniaxial form birefringence with a high contrast between the effective principal dielectric constants. In contrast to conventional dielectric waveguides, the effective modal length for the fundamental mode of the proposed waveguide diverges at a much slower rate for core thicknesses less than a twentieth of the illumination wavelength, and is comparable to that attainable for plasmonic waveguides. The proposed waveguide can be exploited for important applications such as optoelectronic integration, and the fundamental mode exhibits a near-uniform spatial field distribution potentially allowing for position-independent spontaneous emission enhancement effects. | The purpose of this paper is to introduce a semi-blind channel estimation approach for MIMO-OFDM Systems. The proposed method is a combination of pilot and blind channel estimations on Independent Data Blocks (IDB). First, the Pilots are used to find the channel characteristics. By taking the average of subsequent pilot responses we pre-estimating the channel, and then with this pre-estimated channel characteristics data is decoded at the receiver section. In this paper instead of conventional orthogonal pilots proposed optimal pilots and instead of full data block channel estimation half data block channel is estimated using previous and present pilots and next half of data channel characteristics is estimated with interpolating present and future pilots channel, the proposed pattern, method will reduces the MSE as compared to existing conventional one. Simulation results show that the proposed method achieves higher accuracy (MSE reduced) and complexity reduced (compared to blind estimation method). | eng_Latn | 5,412 |
A group communication protocol for CORBA | Group communication protocols are used in fault-tolerant systems to maintain strong replica consistency. The Fault-Tolerant Multicast Protocol (FTMP) described here is a group communication protocol specifically designed for the common object request broker architecture (CORBA). FTMP operates over IP Multicast, and consists of the reliable Multicast protocol (RMP) that provides reliable source-ordered message delivery, the reliable ordered Multicast protocol (ROMP) that provides reliable totally-ordered message delivery, and the processor group membership protocol (PGMP) that provides processor group membership services. | A new approach was proposed for the DOA joint estimation of signal,and the algorithms are based on ESPRIT and two or more array data correlation matrix.It estimated simultaneously the DOA of bis/multistatic.The algorithms estimated parameter are auto paired.The CRLB of the DOA stimation was also derived.The simulating results show that the new methods are equally effective. | eng_Latn | 5,413 |
Reliable Communication Over Arbitrarily Varying Channels Under Block-Restricted Jamming | Time diversity for reliable communication is examined in an information-theoretic framework by investigating information transmission over an Arbitrarily Varying Channel (AVC) under maximum error criterion and introducing the concept of block-restricted jamming. Positivity of the maximum error capacity of an AVC is directly related to the invertibility of the corresponding channel matrix. It is shown that reliable communication over an AVC without additional coordination is possible under block-restricted jamming using repetition coding. | We study the Radiation-Induced Mismatch Enhancement (RIME) in 65 nm CMOS SRAM block designed for space applications. X-ray and heavy ion irradiation increase the number of non-rewriting cells. | eng_Latn | 5,414 |
Least squares approach to data-aided frequency estimation in frequency-selective fading channels | A new data-aided frequency estimator for frequency-selective fading channels is introduced. This estimator is developed based on a least squares (LS) error criterion. The proposed method can estimate frequency offsets without the need for channel information. It is shown through simulation that the proposed LS method can be preferred to the existing techniques in mobile communications. | ABSTRACTIn this paper, using the piecewise linear and quadratic Lagrange interpolation functions, we propose a novel numerical approximate method for the Caputo fractional derivative. For the obtai... | eng_Latn | 5,415 |
The generalized angular momentum crossing relation | Abstract In low energy meson baryon scattering a specific partial wave amplitude in the direct channel will contain contributions from the exchange of resonances in all partial waves in the crossed channel. These contributions, first considered by Carruthers for pion-nucleon scattering, are evaluated in the limit where the baryon kinetic energy is small compared to its mass, and expressed succinctly in terms of a 9 j symbol. Consequences for bootstrap theory are noted. | Ultra wide band (UWB) impulse radio (IR) technology calls for robust and low-complexity receiver techniques. State-of-the-art proposals are both coherent ML receivers, noncoherent transmitted reference systems, or hybrid choices, all of which are derived from an AWGN model. In this paper we investigate an alternative technique which has been recently proposed, and which is based upon a Gaussian mixture (GM) model for multiple access interference. We show that this technique exhibits superior performance in comparison to AWGN receivers, and can be implemented with low-complexity. | eng_Latn | 5,416 |
A preamble-aided symbol and frequency synchronization scheme for OFDM systems | Orthogonal frequency division multiplexing is considered to be an appealing modulation technique for high-speed wireless communication systems owing to its spectral efficiency and robustness against multipath fading. However, an OFDM system is very sensitive to synchronization and a small frequency or timing offset may cause a large intercarrier interference (ICI), leading to a dramatic degradation in system performance. The paper presents an efficient symbol and frequency synchronization scheme for OFDM systems that is compatible with the IEEE 802.16a standard. A timing algorithm is proposed based on the preamble defined in IEEE 802.16a. The conjugate symmetry of the preamble structure is exploited to reduce computational complexity. It is shown that the new scheme not only reduces the estimation error significantly, but also allows for independent symbol synchronization compared to the conventional methods where fine timing usually has to be done after the frequency offset correction. | This book, which was first published in Russian in 2005, deals with the homogenization of partial differential equations (pdes) of elliptic and parabolic types. The authors study both boundary value problems posed in highly perforated domains or equations with rapidly oscillating coefficients. The standard theory of homogenization (periodic theory, uniformly elliptic oscillating coefficients) is supposed to be already known and the emphasis is put on nonstandard situations leading to multicomponent or nonlocal equations. | eng_Latn | 5,417 |
Order statistics based diversity combining for fading channels | We present a new order statistics based diversity combining scheme (OSDC) for combining a set of independently fading signal amplitudes. The OSDC orders all the received signal amplitudes and uses only the two strongest signals in the combining process. The decision as to whether to use only the strongest or both the strongest and the next strongest is mane depending on the relative strengths of these two highest order statistics. Signal-to-noise ratio performance of the new scheme is compared with that of the traditional schemes such as, selection combining, maximal ratio combining, equal gain combining, and a second order selection combining (SC2), for three channels, namely Rayleigh, Nakagami and exponential. The results show that OSDC performs as well as SC2. | The space distribution pattern of the Neosyrista similis was researched from April to May in 2005.By using 6 kinds of analyzing index,including the diffusion coefficient,we confirmed the space distribution pattern of the insect was aggregated distribution,the distributing fundamental component was individual.By using the population aggregation average mensuration of Blackith,the aggregation was caused by some environmental factor such as climate,the growth status of plants and the variety resistance to insects.This paper put forward the best theory sample result. | eng_Latn | 5,418 |
Performance of a subcarrier intensity modulated differential phase-shift keying over generalized turbulence channel | Abstract Optical wireless communication technologies are finding a greater interest and wider attention within the research community of late. In this paper, we investigate the performance of a free space optical communication system over a generic propagation model called M -distributed channel in the presence of atmospheric turbulence. We analyzed a Subcarrier intensity-modulated free-space optical (SIM-FSO) communication system using DPSK and closed form expressions are derived using Meijer G function for bit error rate, channel capacity and outage probability for M -distribution. | The ratio of the axial to vector neutron decay constants is determined via QCD sum rules. The advantageous use of the arbitrariness in the definition of the nucleon operator leads to a result which is unambiguous. The only input parameter is the value of the chiral symmetry breaking vacuum quark condensate.\(\langle \bar \Psi \Psi \rangle ^{{1 \mathord{\left/ {\vphantom {1 3}} \right. \kern-\nulldelimiterspace} 3}} = - 250 MeV\) the output isgA/gV=1.22. | eng_Latn | 5,419 |
A novel pre-coding orthogonal full diversity space-time block coding scheme for 4×4 MIMO system | In this paper we consider a novel design of space-time block code combined with pre-coding module transmission system. Theory of orthogonal designs has shown that such code cannot be simultaneously orthogonal, of rate 1, with full diversity order, for more than 2 transmit antennas. We propose in this paper a new way to overcome this limitation by adding a pre-coding module before transmitting space-time block signals, this scheme is a rate 1 coding scheme with full diversity, and is also an orthogonal one thanks to the new adding pre-coding weights. | We present an algorithm for model checking temporal-epistemic properties of multi-agent systems, expressed in the formalism of interpreted systems. We first introduce a technique for the translation of interpreted systems into boolean formulae, and then present a model-checking algorithm based on this translation. The algorithm is based on obdd's, as they offer a compact and efficient representation for boolean formulae. | eng_Latn | 5,420 |
Outage analysis for joint antenna and path selection decode-and-forward relay networks | Abstract In this paper, we consider a multiple-input multiple-output (MIMO) cooperative communication system with single decode and forward (DF) relay. The system performance is analyzed by using joint antenna and path selection (JAPS) scheme over Nakagami-m fading channel. Then, we propose to use both JAPS and Sub-optimal transmit antenna selection strategy denoted by JAPS/maximum-ratio combining (JAPS/MRC) to improve the coding gain performance. For JAPS, a closed-form expression for the outage probability (OP) is derived. The upper bound of OP in high signal-to-noise ratio (SNR) regime is obtained. For JAPS/MRC a closed-form expression for the OP is also derived. The derived expressions are applicable with any number of antennas, different m i and distinct average SNRs between the paths. Simulation results are presented and show the validity of our theoretical analysis. | Standard basic encoding rules are too elaborate and inefficient for distributed real-time applications. Two major obstacles encountered are long protocol data units and slow encoding times. The problem of encoding for real-time applications is addressed. Taking Fieldbus as a representative of real-time networks, it is shown why the encoder should be simplified and how this can be done. The impact of encoders, in general, on the overall network performance is studied. Implementation results demonstrate the efficiency of the proposed encoder. > | eng_Latn | 5,421 |
Enhancement of noisy speech using sub-band harmonic regeneration and speech presence uncertainty estimator | This paper presents a noise reduction technique based on sub-band harmonic regeneration with Speech Presence Uncertainty (SPU). Harmonic Regeneration (HRNR) overcomes the harmonic distortion, which is significant at low SNR values by preserving harmonics. For further noise suppression at low SNRs, Sub-band modification of HRNR gain with weights calculated using speech presence uncertainty is proposed. Objective (SNR, SegSNR, LLR, WSS) performance measures show that the proposed method provides superiority in noise reduction and measures like SNR and SegSNR shows better speech preservation at high SNRs, better noise suppression at low SNRs. | We assume a CDMA downlink multiuser scenario, where the base station is equipped with multiple transmit antennas, and each user has multiple receive antennas. For this setup we propose a new, computationally effective MIMO multiuser detector for frequency selective channels. We exploit the fact that the interference mainly comes from the spatial domain, while the residual interference is due to temporal dispersion and multiuser interference. This motivates us to suppress the residual interference in a linear fashion, while combating the spatial interference iteratively. This approach is an efficient performance-complexity tradeoff between fully iterative and linear detectors. | eng_Latn | 5,422 |
The Application of Hall-Effect Devices to the Measurement of Microwave Power Density | A theory is developed that indicates a Hall-effect device should function as both a collector and transducer of microwave electromagnetic energy giving an output dc voltage signal proportional to power density. Results are described of experiments using Hall-effect devices in coaxial lines and free fields. These are concerned with Hall device output voltage and VSWR of the coaxial line as frequency, power density level, and control current lead length were varied independently. Output voltages vary linearly with power density, but show high frequency dependence and the presence of voltage generating effects in addition to the Hall effect. Considerations are given to the identification and separation of these undesired voltages. Conclusions indicate additional research is necessary. | We assume a CDMA downlink multiuser scenario, where the base station is equipped with multiple transmit antennas, and each user has multiple receive antennas. For this setup we propose a new, computationally effective MIMO multiuser detector for frequency selective channels. We exploit the fact that the interference mainly comes from the spatial domain, while the residual interference is due to temporal dispersion and multiuser interference. This motivates us to suppress the residual interference in a linear fashion, while combating the spatial interference iteratively. This approach is an efficient performance-complexity tradeoff between fully iterative and linear detectors. | eng_Latn | 5,423 |
Fast, noise-free memory for photon synchronization at room temperature | Future quantum photonic networks require coherent optical memories for synchronizing quantum sources and gates of probabilistic nature. We demonstrate a fast ladder memory (FLAME) mapping the optical field onto the superposition between electronic orbitals of rubidium vapor. Employing a ladder level-system of orbital transitions with nearly degenerate frequencies simultaneously enables high bandwidth, low noise, and long memory lifetime. We store and retrieve 1.7-ns-long pulses, containing 0.5 photons on average, and observe short-time external efficiency of 25%, memory lifetime (${1/e}$) of 86 ns, and below ${10^{-4}}$ added noise photons. Consequently, coupling this memory to a probabilistic source would enhance the on-demand photon generation probability by a factor of 12, the highest number yet reported for a noise-free, room-temperature memory. This paves the way towards the controlled production of large quantum states of light from probabilistic photon sources. | In recent years, MIMO communication systems such as IMT-Advanced and LTE have been put into practical use. Since MIMO transmission has an advantage in use in the indoor multipath-rich environment, the accurate indoor MIMO channel model is required for evaluating the systems. In the indoor environment, it is known that the channel state changes dynamically due to the human shadowing effect even if the receiver and the transmitter are fixed. In this paper, we propose the data analysis method of measured data for the indoor channel modeling. In our proposal, the propagation parameters of rays are estimated using SAGE algorithm. Then the rays are clustered using K-Power-Means algorithm. Next the human body shadowing of each cluster is estimated according to the resultant power variation of cluster. We carried out the measurements at 3.35GHz in the indoor environment and estimated the human body shadowing of each cluster. | eng_Latn | 5,424 |
Evaluation of diversity gains for DVB-T systems | The requirements for future DVB-T/H networks demand that broadcasters design and deploy networks that provide ubiquitous reception in challenging indoors and other obstructed situations. It is essential that such networks are designed costeffectively and with minimized environmental impact. The EC funded project PLUTO has since its start in 2006 explored the use of diversity to improve coverage in these difficult situations. The purpose of this paper is to investigate the performance of transmit and receive diversity gains with two antennas to improve the reception of DVB-T/H systems operating in different realistic propagation conditions through a series of tests using the Spirent dual channel emulator. | The problem of maximizing utility over the capacity region of the MIMO broadcast channel is addressed. While a direct solution is not possible, it is discussed how decomposition techniques can be used to find an optimum solution. Two decompositions are considered: A standard dual decomposition and a gradient projection-based decomposition. | eng_Latn | 5,425 |
Rate-2 Space-Time Block Code with Phase Rotation | The full rate and full diversity could be achieved by Rate-2 space-time block code,whereas the decoding complexity is proportional to the square of the modulation order.A rate-2 space time block code with phase rotation is proposed in order to reduce the decoding complexity.Part of the transmitted signals is rotated by a certain angle,and the pairwise orthogonal between the transmitted signals is realized in the proposed scheme,so that the decoding complexity is proportional to the modulation order.Simulation results demonstrate the decoding complexity is reduced greatly by proposed code only with 7 bit feedback. | In an earlier paper by the author the problem of determining the optimum symmetrical weighting factors for a video MTI radar was discussed. This paper extends this work so as to remove the symmetrical restriction from the problem. In addition, for a staggered pulse system, optimum times of transmission are determined. In the earlier paper a global solution to the restricted optimization problem was achieved. In this paper only a locally optimum solution is achieved for the more general problem. | eng_Latn | 5,426 |
Reducing the peak and average power for OFDM systems using QAM by constellation shaping | In this paper, we present a shell mapping scheme to reduce the peak and average power of orthogonal frequency division multiplexing (OFDM) signals using quadrature amplitude modulation (QAM) by constellation shaping. Our approach can be considered as an extension of the shell mapping technique introduced originally in the V.34 recommendation of ITU-T. The shell mapping method uses multiple cost functions, each having the OFDM block length N as a parameter. The cost functions are presented in closed form for any N. The main advantage of the proposed scheme is that the peak and average power can be reduced without sacrificing the data rate, and no side information is needed at the receive side. We apply our constellation shaping technique to OFDM systems with N equal to 16, 32 and 128 subcarriers. The results show that the peak and average power decrease with increasing values of N. This advantage is partly offset by a slightly higher system complexity. Copyright © 2009 John Wiley & Sons, Ltd. | We present a novel technique for accurately estimating the proportions of packet losses arising from collisions and from other sources of loss (channel noise, hidden nodes etc). Our approach is robust, makes use of local station-level measurements and requires no message passing. The required measurements are available in standard hardware as they are required for CSMA/CA operation. No channel quality probing is required which ensures energy efficiency | eng_Latn | 5,427 |
IP-based Signal Transmission System Application in Radio and Broadcast Network | In this paper,signal transmission requirement is listed in radio and televison netwrok,transmission system current situation and shortage are introduced firstly.And then,the characteristics and advantages of IP-based transmission system,including different carrying network and signal multepexing system are elaborated in detail.Afterwards,system application architecture with other systems are explained.Finally a summary of transmission system and outlook are made. | A matrix Routh-approximant modelling procedure is proposed for a multi-input multi-output system characterized by a matrix transfer function G(s), where G(s) = B(s) A −1(s) and A(s) and B(s) are matrix polynomials in s. The associated time-domain modelling procedure is also discussed. Compared with three matrix Cauer continued-fractions, the proposed method requires less computational effort. In addition, it is applicable to systems with unequal number of inputs and outputs. A demonstrative example is included. | eng_Latn | 5,428 |
Tree structures for time-frequency signal analysis | The popular orthonormal decomposition techniques such as block transforms and filter banks for multiresolution signal representation are unified. Their comparative performance results based on signal energy compaction are presented for image and AR(1) sources. It is observed that the filter banks with computationally efficient filtering algorithms and irregular tree structures are potential competitors to the block transforms, particularly for image processing and coding applications. > | This paper presents a kind of symbol synchronization based on cyclic prefix.This algorithm based on ML estimation algorithm,improve and simplifies symbol synchronization method in the operation,not only optimises the system in hardware resources, but also improves the performance of estimation.By simulating in Matlab and implementing in FPGA based on the IEEE 802.11a,we successfully further verified the feasibility of the algorithm.The results show that the system is reliable and can meet the design requirements. | eng_Latn | 5,429 |
Experimental analysis of fibre non-linearity on second harmonic optical microwave radio-over-fibre system | In this study, the authors propose an optical microwave (MW) radio-over-fibre system in which an integrated dual-parallel Mach-Zehnder modulator (DP-MZM) is biased at the maximum transmission biasing point. A single drive Mach-Zehnder modulator, in series with the DP-MZM, is used to modulate the 1 GHz radio frequency data onto the optical carrier. They characterise the efficiency of the practical system in terms of power penalty and error vector magnitude. Two modulation schemes are investigated, namely binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK) over fibre spans of 10 and 25 km of standard single mode fibre. The results show that the second-order sideband of MW has the potential to provide error free transmission for BPSK and QPSK. The error free communication system is achieved for BPSK at 10 and 25 km fibre spans at optical launch power (OLP) of 7 dBm, whereas for QPSK, the OLP is ~11 and ~12 dBm for 10 and 25 km fibre spans, respectively. | Often, the exact model of industrial processes turns out to be too complex for simulation and controller design. It is therefore mandatory to simplify the mathematical description of the process and/or the one of the controller. A particularly attractive simplification criterion is related to the minimization of the L 2 norm of the approximation error. This paper presents an algorithm for solving the L 2-optimal MIMO model reduction problem. It is shown that its convergence to the minima of the approximation error norm is guaranteed. The algorithm proves to be fast and efficient compared to other algorithms suggested in the literature to the same purpose. | eng_Latn | 5,430 |
The Gaussian Many-Help-One Distributed Source Coding Problem | Jointly Gaussian memoryless sources are observed at N distinct terminals. The goal is to efficiently encode the observations in a distributed fashion so as to enable reconstruction of any one of the observations, say the first one, at the decoder subject to a quadratic fidelity criterion. Our main result is a precise characterization of the rate-distortion region when the covariance matrix of the sources satisfies a ?tree-structure? condition. In this situation, a natural analog-digital separation scheme optimally trades off the distributed quantization rate tuples and the distortion in the reconstruction: each encoder consists of a point-to-point Gaussian vector quantizer followed by a Slepian-Wolf binning encoder. We also provide a partial converse that suggests that the tree-structure condition is fundamental. | Based on the traditional adaptive multiuser detection method,sum up application of new LMS,RLS,Kalman arithmetics in DS-CDMA Multiuser detection.principles and methods of 3 arithmetics were given and emulation by Matlab.Based on comparing with SIR and errorcode of 3 arrthmetic,Kalman arithmetic show more excellent detection performance. | eng_Latn | 5,431 |
SLM and PTS peak-power reduction of OFDM signals without side information | Selected mapping (SLM) and partial transmit sequence ::: (PTS) are well-known techniques for peak-power reduction ::: in orthogonal frequency-division multiplexing (OFDM). We ::: derive a simplified maximum likelihood (ML) decoder for SLM ::: and PTS that operates without side information. This decoder ::: exploits the fact that the modulation symbols belong to a given ::: constellation and that the multiple signals generated by the PTS or ::: SLM processes are widely different in a Hamming distance sense. ::: Pairwise error probability (PEP) analysis suggests how SLM and ::: PTS vectors should be chosen. The decoder performs well over ::: additive white Gaussian noise (AWGN) channels, fading channels, ::: and amplifier nonlinearities. | This paper addresses the problem of channel and propagation delay estimation in asynchronous DS/CDMA systems. We consider the uplink connection in DS/CDMA with long spreading codes. The MIMO stochastic gradient algorithm proposed in [6] is estimating a linear combination of the channel impulse responses and the propagation delays. This estimate suffices for the equalization purposes. The propagation delays are estimated with a simple matching scheme. | eng_Latn | 5,432 |
A new joint iterative detecting algorithm in high-order modulation MIMO systems | This article imports an improved multistage sphere decoding (IMSD) algorithm into the MMSE-PIC iterative structure and proposes a new joint iterative detecting structure in high order modulation MIMO systems. The IMSD algorithm is designed against the higher-order modulation system with lower complexity and near SD performance. The new structure replaces the MMSE liner detector with the IMSD detector in the first round iteration of original MMSE-PIC structure, which has better performance and lower sensitivity towards channel correlation. | This paper studies the secure multiterminal source coding problem with actions. In particular, one main encoder observes an independent and identically distributed (i.i.d.) source Xn and wishes to compress this source lossyly to the decoder. Another encoder observes the source Yn and wants to compress this source losslessly to the decoder. A passive eavesdropper having access to the side information Zn can observe the information bits sent by the main encoder. In this scenario, the decoder is allowed to choose actions affecting the correlated source Yn and the side information Zn. For this problem, we characterize the optimal rate-distortion-cost-leakage region for a discrete memoryless setting. | eng_Latn | 5,433 |
Performance evaluation of downlink LTE system with QPP interleaver for channel encoder | The design of the LTE physical layer (PHY) is heavily influenced by the requirements for high peak transmission rate (100 Mbps DL/50 Mbps UL), spectral efficiency and multiple channel bandwidths (1.25–20 MHz). Unfortunately, the existing WCDMA turbo interleaver does not permit an efficient high throughput implementation. That is why the 3rd Generation Partnership Project (3GPP) has proposed the quadratic polynomial permutation (QPP) interleaver to rectify this situation. In this paper, we will study the performances of QPP interleaver for LTE encoder channel for different configurations of LTE system and we study the effect of LTE channel turbo encoder for the transmission over a wireless multipath channel. | We propose an embarrassingly parallel, memory ecient inference algorithm for latent variable models in which the complete data likelihood is in the exponential family. The algorithm is a stochastic cellular automaton and converges to a valid maximum a posteriori fixed point. Applied to latent Dirichlet allocation we find that our algorithm is over an order or magnitude faster than the fastest current approaches. A simple C++/MPI implementation on a 20-node Amazon EC2 cluster samples at more than 1 billion tokens per second. We process 3 billion documents and achieve predictive power competitive with collapsed Gibbs sampling and variational inference. | eng_Latn | 5,434 |
Chromatin Immunoprecipitation (ChIP) Analysis of Protein-DNA Interactions. | Here we describe chromatin immunoprecipitation (ChIP), a molecular approach that uses formaldehyde cross-linking to investigate genome structure and function. This approach allows us to determine the distribution of histone modifications (e.g., acetylation, methylation), the deposition of histone variants (H2AZ, H3.3, etc.), and the location of sequence-specific and general transcription factors. We introduce well-established ChIP-based methods that allow analysis of protein-DNA interactions in living cells. | In practical systems, due to the time-varying radio channel, the channel state information (CSI) may not be known well at both transmitters and receivers. For most of the current multiuser multiple-input multiple-output (MIMO) schemes, they suffer a significant degression on the performance due to the mismatch between the true and estimated CSI. To alleviate the performance penalty, a robust downlink multiuser MIMO scheme is proposed in this paper by exploiting the channel mean and antenna correlation. These channel statistics are more stable than the imperfect CSI estimation in the time-varying radio channel, and they are used, in the proposed scheme, to minimize the total mean squared error under the sum power constraint. Simulation results demonstrate that the proposed scheme effectively mitigates the performance loss due to the CSI mismatch. | kor_Hang | 5,435 |
Improved GA solution on LNC coefficient matrix for multi-user cooperative communication | Cooperative communication with network coding can yield higher system diversity gain and improve the efficiency of cooperation, for which designing the proper and efficient coding coefficients is one key technique for implementation. The important contributions of our work reveal the existence of coding coefficient matrix of order M constructed in GF(M = 2n) and propose practical and effective method to search such matrix. An improved genetic algorithm solution is proposed by introducing the local gradient search mechanism for large searching space and the search results show that the proposed method can obtain satisfying solutions and better computing performance for M = 8 in GF(8). The discussion on improved local gradient search mechanism illustrates its underlying potentials in global search framework. This work gains an insight into the coefficient matrix construction for cooperative communication with network coding in GF(2n). | The authors would like to thank the helpful suggestions and ::: comments from the Editor, the Associate Editor, and the ::: Reviewers. The authors are also grateful to Karen J. Duncan ::: for her contribution in the language revision. The first ::: author’s work has been partially supported by the Spanish ::: National Research and Development Program project ::: [TEC2015-65353-R], by the European Regional Development ::: Fund (ERDF), and by the Galician Regional Government ::: under project GRC 2015/018 and under agreement for ::: funding AtlantTIC (Atlantic Research Center for Information ::: and Communication Technologies). The second author ::: acknowledges financial support from the Portuguese Funds ::: through FCT-“Fundacao para a Ciencia e a Tecnologia,” ::: within the Project UID/MAT/00013/2013. | eng_Latn | 5,436 |
Dynamical Casimir Effect with Semi-Transparent Mirrors, and Cosmology | After reviewing some essential features of the Casimir effect and, specifically, of its regularization by zeta function and Hadamard methods, we consider the dynamical Casimir effect (or Fulling–Davies theory), where related regularization problems appear, with a view to an experimental verification of this theory. We finish with a discussion of the possible contribution of vacuum fluctuations to dark energy, in a Casimir-like fashion, that might involve the dynamical version. | In this paper we propose a compressive channel estimation for fast fading channel in orthogonal frequency division multiplexing (OFDM) systems. We formulate the sparse compressive sensing (CS) problem by exploiting the delay-Doppler sparse structure of the doubly dispersive channel. To combat the severe inter-carrier interference (ICI) caused by the Doppler shift, this estimator is based on the banded matrix model in frequency domain. The band approximation enable the CS technology to obtain a precise estimation of the fast fading channel with feasible complexity. We also utilize the random grouped pilot pattern, which allows a direct construction of measurement matrix for the proposed model. Simulation results demonstrate that our method achieves significant performance gain when the Doppler spread is at high level. | eng_Latn | 5,437 |
Frequency-Domain Hammerstein Self-Interference Canceller for In-Band Full-Duplex OFDM Systems | Practical, real-time, full duplex wireless | Effective injury forecasting in soccer with GPS training data and machine learning | eng_Latn | 5,438 |
Electromagnetic Lens-Focusing Antenna Enabled Massive MIMO: Performance Improvement and Cost Reduction | Joint Tx-Rx beamforming design for multicarrier MIMO channels: a unified framework for convex optimization | Quality of life, functioning and cognition in bipolar disorder and major depression: A latent profile analysis | eng_Latn | 5,439 |
Replacement of a Single-Channel with a Multichannel Cochlear Implant as an Upgrade | The removal of a functioning cochlear implant in order to upgrade to a more advanced device is a critical issue to many otologists, since we currently have no means to predict the results preoperatively. This paper reports on two patients who successfully upgraded from a single-channel to a multichannel implant. The new implants outperformed the original devices in both the live-voice test and the videotaped test. The patients stated that the hearing quality afforded by the multichannel implant was much better than that provided by the original implant. | In this paper, a new method is proposed to adaptively estimate the number of transmit antennas in cognitive radios and surveillance systems. It employs Schur complement to test the linearly independence of the new coming data with the previous data set. ?2 test is conducted based on the statistics of Schur complement variable. Last, Monte Carlo simulation is employed to test the performance of the estimator under different scenarios. | eng_Latn | 5,440 |
Performance Analysis and Implementation of Array Multiplier using various Full Adder Designs for DSP Applications: A VLSI Based Approach | Multipliers are the significant arithmetic units which are used in various VLSI and DSP applications. Besides their crucial necessity, Multipliers are also a main source for power dissipation. Hence prior importance must be given to lessen power dissipation in order to satisfy the overall power budget for various digital circuits and systems. Multiplier performance is directly influenced by the adder cells employed, for multipliers designed using adders; therefore power dissipation problem can be solved by exploring and using better adder designs. In this paper various full adder designs are analyzed in terms of delay, power consumption and area, As the adder block is prime concern for array multiplier in order to propose an efficient Multiplier architecture. The design and implementation of full adder cells and multiplier is performed on CADENCE design suite at GPDK 180 nm technology. The CMOS, GDI and Optimized full adder design is employed to implement array multiplier. | In vector four-wave mixing, one or two strong pump waves drive two weak signal and idler waves, each of which has two polarization components. In this paper, vector four-wave mixing processes in a randomly-birefringent fiber (modulation interaction, phase conjugation and Bragg scattering) are studied in detail. For each process, the Schmidt decompositions of the coupling matrices facilitate the solution of the signal-idler equations and the Schmidt decomposition of the associated transfer matrix. The results of this paper are valid for arbitrary pump polarizations. | eng_Latn | 5,441 |
Transmission of ultrashort coherent pulses through the ionosphere | A study is made of scattering and absorption of ultrashort coherent radiation pulses when they pass through an electron gas, such as occurs in the ionised upper layers of the atmosphere. | This work describes a method for providing robustness to errors from a binary symmetric channel for the SPIHT image compression. The source rate and channel rate are jointly optimized by a stream of fixed-size channel packets. Punctured turbo codes are used for the channel coding, providing stronger error protection than previously available codes. We use a subset of the puncturing patterns that are well chosen and that leads to the best source rate. The rate allocation scheme presented obtains all necessary information from the SPIHT encoder, and does not require image decompression. | eng_Latn | 5,442 |
Influence of Asphyxia on Reciprocal Innervation | In cats whose spinal cords had been asphyxiated for various periods of time, van Harreveld and Marmont1 found that after recovery the hind legs could show an exaggerated extensor tone which usually stayed until death (in some experiments 3 weeks in total). Considering that after this time the acute effect of asphyxia will have disappeared, it was concluded that the high extensor tone is caused by a more or less selective damage of an inhibiting system present in the cord which normally keeps the tone in check.A further study of these phenomena was made. A period of asphyxia for 30 minutes was usually followed within a few hours by the development of high extensor tone without abolishment of the flexor reflex. However, the effect of pinching the foot was not the same in all animals; sometimes it caused a regular flexor reflex with flexion in ankle and knee; in other experiments it caused, after the flexion, an extension of the leg, and in a few cases this stimulus caused instead of flexion an increase of t... | Channel estimation is an essential component, in which channel state information playing very important role in wireless communications. But acquiring CSI in practice is a challenging issue for massive MIMO systems. To reduce the over burden for obtaining channel impulse response of huge Multi input multi output system channel reciprocity in TDD domain is suggested, because the forward link channel data can be derived from the reverse link signal without any feedback involvement. Because of mismatches at uplink, downlink channels maintaining reciprocity in TDD systems is impractical. We study the impact of multiplicative reciprocity error for precoders (Zero forcing, MMSE and MRT) performance along with channel estimation error. In this paper effect of RF mismatches impact on linear precoders is analyzed and simulated in terms of SINR versus SNR under additive white Gaussian noise. | eng_Latn | 5,443 |
Quantum particle swarm evolutionary algorithm with application to system identification | Based on quantum evolutionary algorithm and particle swarm optimization, a quantum particle swarm evolutionary algorithm is proposed. In this algorithm, quantum angle is used to represent the qubit, a new method learning from the idea of particle swarm algorithm is presented to determine rotation angle, He gate is taken to prevent from premature convergence. Applying this algorithm to identify system parameter, and comparing with conventional genetic algorithm and quantum evolutionary algorithm, the experimental results illustrate that the proposed algorithm has better performance than that of others. Meanwhile, it can also keep high identification ability to the system with the existence of noise. | The design of the LTE physical layer (PHY) is heavily influenced by the requirements for high peak transmission rate (100 Mbps DL/50 Mbps UL), spectral efficiency and multiple channel bandwidths (1.25–20 MHz). Unfortunately, the existing WCDMA turbo interleaver does not permit an efficient high throughput implementation. That is why the 3rd Generation Partnership Project (3GPP) has proposed the quadratic polynomial permutation (QPP) interleaver to rectify this situation. In this paper, we will study the performances of QPP interleaver for LTE encoder channel for different configurations of LTE system and we study the effect of LTE channel turbo encoder for the transmission over a wireless multipath channel. | eng_Latn | 5,444 |
Reproducibility of resting metabolic rate measurement in children | The aim of the present study was to determine the reproducibility of measurement of resting metabolic rate (RMR) using a ventilated-hood indirect calorimeter in children using a short protocol suitable for the outpatient setting or home visit. The protocol consisted of an overnight (10-12 h) fast, 5-10 min supine rest, 5-10 min 'settling in' under the ventilated hood, and 12-16 min of measurement. Three measurements of RMR were made in eighteen healthy children (nine boys, nine girls, aged 6-11 years) on alternate days. Reproducibility of RMR was assessed using a reproducibility index and by calculating the CV for intra-individual measurements. The mean CV was 2.6 (SD 1.7)% and the reproducibility index was 95.0%, indicating excellent reliability. The short protocol had higher reproducibility than more stringent protocols described in the literature. The new protocol has a number of practical advantages and should be adequate for most clinical or research purposes. | Channel estimation is an essential component, in which channel state information playing very important role in wireless communications. But acquiring CSI in practice is a challenging issue for massive MIMO systems. To reduce the over burden for obtaining channel impulse response of huge Multi input multi output system channel reciprocity in TDD domain is suggested, because the forward link channel data can be derived from the reverse link signal without any feedback involvement. Because of mismatches at uplink, downlink channels maintaining reciprocity in TDD systems is impractical. We study the impact of multiplicative reciprocity error for precoders (Zero forcing, MMSE and MRT) performance along with channel estimation error. In this paper effect of RF mismatches impact on linear precoders is analyzed and simulated in terms of SINR versus SNR under additive white Gaussian noise. | eng_Latn | 5,445 |
Radiometric definitions for partially coherent sources | New generalizations of the basic radiometric concepts of radiance, radiant emittance, and radiant intensity to fields generated by a two-dimensional stationary partially coherent source are made. It is explicitly shown how they are related to the cross-spectral density of the source. Such new definitions are consistent with the postulates of traditional radiometry. | The performance of a pragmatic carrier phase estimation algorithm is evaluated over a range of SNRs. The optimal SNR regions for MQAM are compared to an AWGN channel observing gains of up to 40% in throughput. | eng_Latn | 5,446 |
Clinical value of serum and urine κ /λ light chain in diagnosis of multiple myeloma | Objective To investigate the clinical value of serum and urine κ /λ light chain in diagnosis of multiple myeloma( MM). Methods A total of 66 MM patients and 30 healthy controls were enrolled in this study. The levels of serum and urine κ/λ light chain were measured by rate nephelometry. The sensitivity and specificity of κ/λ light chain for detecting MM were evaluated. Results The levels of serum and urine κ / λ light chain were higher in 66 MM patients compared to healthy controls( P 0. 05). And more significant differences were found between the male patients above 40 years old and healthy controls( P 0. 01). Conclusion The combined determination of serum and urine κ/λ light chain shows high sensitivity and specificity in the diagnosis of multiple myeloma( MM). The method was convenient,rapid and without hurt. So it is helpful to early prevent the multiple myeloma promptly,especially in the male patients above 40 years old. | In recent years, MIMO communication systems such as IMT-Advanced and LTE have been put into practical use. Since MIMO transmission has an advantage in use in the indoor multipath-rich environment, the accurate indoor MIMO channel model is required for evaluating the systems. In the indoor environment, it is known that the channel state changes dynamically due to the human shadowing effect even if the receiver and the transmitter are fixed. In this paper, we propose the data analysis method of measured data for the indoor channel modeling. In our proposal, the propagation parameters of rays are estimated using SAGE algorithm. Then the rays are clustered using K-Power-Means algorithm. Next the human body shadowing of each cluster is estimated according to the resultant power variation of cluster. We carried out the measurements at 3.35GHz in the indoor environment and estimated the human body shadowing of each cluster. | eng_Latn | 5,447 |
Ways to strengthen the weak spread spectrum signal to cancel a strong signal | (57) The invention provides a method for enhancing the tracking capability of the strong signal interference determined weak signal in the CDMA coded spread spectrum radio signal to the received weak signal including the intensity signal. A two signals modulation code is known to predict the weak signal. For strong signal strength and strong signals and weak signal determining an interference strength signal as a product (40) between the predicted strong signal interference (50). Measuring the intensity signals from both methods, it is possible to predict or obtain (10). It is possible to predict the cross-correlation with respect to the weak signal is selected as the predicted value for maximum reception strength range of weak signal value (60). | We consider the MIMO wiretap channel, that is a MIMO broadcast channel where the transmitter sends some confidential information to one user which is a legitimate receiver, while the other user is an eavesdropper. Perfect secrecy is achieved when the transmitter and the legitimate receiver can communicate at some positive rate, while insuring that the eavesdropper gets zero bits of information. In this paper, we compute the perfect secrecy capacity of the multiple antenna MIMO broadcast channel, where the number of antennas is arbitrary for both the transmitter and the two receivers. Our technique involves a careful study of a Sato-like upper bound via the solution of a certain algebraic Riccati equation. | eng_Latn | 5,448 |
15MHz wide tuning-range OTA with −69dBHD3 and its application to Gm-C filter | This paper presents a high linearity operational transconductance amplifier (OTA). The OTA circuit combines the techniques of the double differential pairs (DDP) and Source-degenerated current mirrors to achieve high linearity in a large GM tuning range. With the Gm values ranged from 60µS to 130µS, the HD3 of the OTA is below −69dB at 15MHz. The OTA has been applied to a fourth-order linear phase low-pass filter for high speed system. The fourth-order low-pass filter with the cutoff frequency of 15MHz has been implemented. The filter is designed by 0.18-µm CMOS process technology, the HD3 performance is about −53dB, and the group delay variation is below 5% at cutoff frequency. | We consider the MIMO wiretap channel, that is a MIMO broadcast channel where the transmitter sends some confidential information to one user which is a legitimate receiver, while the other user is an eavesdropper. Perfect secrecy is achieved when the transmitter and the legitimate receiver can communicate at some positive rate, while insuring that the eavesdropper gets zero bits of information. In this paper, we compute the perfect secrecy capacity of the multiple antenna MIMO broadcast channel, where the number of antennas is arbitrary for both the transmitter and the two receivers. Our technique involves a careful study of a Sato-like upper bound via the solution of a certain algebraic Riccati equation. | eng_Latn | 5,449 |
Neural Networks with Limited Precision Weights and Its Application in Embedded Systems | A type of optimized neural networks with limited precision weights (LPWNN) is presented in this paper. Such neural networks, which require less memory for storing the weights and less expensive floating point units in order to perform the computations involved, are better suited for embedded systems implementation than the real weight ones. Based on analyzing the learning capability of LPWNN, Quantize Back-propagation Step-by-Step (QBPSS) algorithm is proposed for such neural networks to overcome the effects of limited precision. Methods of designing and training LPWNN are represented, including the quantization of non-linear activation function and the selection of learning rate, network architecture and weights precision. The optimized LPWNN performance has been evaluated by comparing to conventional neural networks with double-precision floating-point weights on digital recognition in ARM embedded systems, and the results show the optimized LPWNN has 11 times faster than the conventional ones. | In this paper the least squares problem of signal estimation is introduced. The Code-Division Multiple Access (CDMA) signal model is transformed into a least squares minimization form. Based on the solutions of the problem, different receiver structures are derived. Channel estimation using least-squares method is also considered. The NMSE is used as a performance measure for the estimator. The performance of the different receivers is analyzed over AWGN channel. Performance over flat fading channel is also considered with and without channel estimation. The proposed receiver is modified to accommodate detection over frequency-selective fading channels with a least-squares channel estimator block. | eng_Latn | 5,450 |
A linearized second-order finite difference scheme for time fractional generalized BBM equation | Abstract In this paper, we consider the generalized Benjamin–Bona–Mahony (BBM) equation with a fractional order derivative in time. By introducing a weighted approach and basing on the L 2 - 1 σ formula, a linearized finite difference scheme is proposed to solve the nonlinear problem. The scheme is shown to be unconditionally convergent with second-order in time and space within maximum-norm estimate. | Deterministic network calculus (DNC) is not suitable for deriving performance guarantees for wireless networks due to their inherently random behaviors. In this paper, we develop a method for Quality of Service (QoS) analysis of wireless channels subject to Rayleigh fading based on stochastic network calculus. We provide closed-form stochastic service curve for the Rayleigh fading channel. With this service curve, we derive stochastic delay and backlog bounds. Simulation results verify that the bounds are reasonably tight. Moreover, through numerical experiments, we show the method is not only capable of deriving stochastic performance bounds, but also can provide guidelines for designing transmission strategies in wireless networks. | eng_Latn | 5,451 |
Characterization of the optimum transmitter correlation matrix for MIMO with antenna subset selection | We give a simple and complete characterization of the optimum transmitter correlation matrix for multiple-input-multiple-output (MIMO) systems, when antenna subset selection is used. It is assumed that the receiver feeds back to the transmitter only the selected set of antennas without providing any kind of rank ordering of the selected antennas. It turns out that the optimal correlation matrix in this case must be a convex combination of an identity matrix and a matrix whose elements are all ones. This reduces the problem of finding the actual optimum to a one-dimensional search in any given scenario. | Based on the analyses of the interferential multispectral imagery(IMI), a new compression algorithm based on ::: distributed source coding is proposed. There are apparent push motions between the IMI sequences, the relative shift ::: between two images is detected by the block match algorithm at the encoder. Our algorithm estimates the rate of ::: each bitplane with the estimated side information frame. then our algorithm adopts a ROI coding algorithm, in which ::: the rate-distortion lifting procedure is carried out in rate allocation stage. Using our algorithm, the FBC can be ::: removed from the traditional scheme. The compression algorithm developed in the paper can obtain up to 3dB's gain ::: comparing with JPEG2000 and significantly reduce the complexity and storage consumption comparing with ::: 3D-SPIHT at the cost of slight degrade in PSNR. | eng_Latn | 5,452 |
Preliminary Simulation Study of Doppler Reflectometry | A preliminary simulation study of Doppler reflectometry is performed. The simulations solve Maxwell's equations by a finite difference time domain (FDTD) code method in two dimensions. A moving corrugated metal target is used as a plasma cutoff layer to study the basic features of Doppler reflectometry. We examined the effects of the full width at half maximum (FWHM) of the electromagnetic waves and the corrugation depth of the metal target. Furthermore, the effect of a nonuniform plasma is studied using this FDTD analysis. The Doppler shift and velocity are compared with those obtained from FDTD analysis of a uniform plasma. | We assume a CDMA downlink multiuser scenario, where the base station is equipped with multiple transmit antennas, and each user has multiple receive antennas. For this setup we propose a new, computationally effective MIMO multiuser detector for frequency selective channels. We exploit the fact that the interference mainly comes from the spatial domain, while the residual interference is due to temporal dispersion and multiuser interference. This motivates us to suppress the residual interference in a linear fashion, while combating the spatial interference iteratively. This approach is an efficient performance-complexity tradeoff between fully iterative and linear detectors. | kor_Hang | 5,453 |
Improved vacuum assist for a brake booster | An apparatus and a method for providing an increased negative pressure to a brake booster of a brake system under certain operating conditions. A negative pressure is stored in a reservoir and is released controlled under conditions in which the brake booster negative pressure level is less than the predetermined vacuum level threshold to the brake booster to provide a brake booster negative pressure level of at least a predetermined vacuum level threshold in order to avoid that the brake pedal behavior problems of the drivers of motor vehicles be perceived that employ machines that use an additional braking support system. | In this work we have applied Adapive Boosting (AdaBoost) for channel estimation of Orthogonal Frequency Division Multiplexing (OFDM) systems. The result of the AdaBoost algorithm was compared with other algorithms such Least Square (LS), Best Linear Unbiased Estimator (BLUE) and Minimum Mean Square Error (MMSE). | eng_Latn | 5,454 |
Short communication Anxious apprehension increases coupling of delta and beta oscillations | Recent findings showing that anxiety is associated with enhanced coupling of EEG rhythms imply higher information exchange between populations of neurons associated with different oscillatory systems. In this study, influence of uncertainty on alpha–delta anticorrelation and delta–beta coupling was studied in 39 subjects (27 females) aged 19 to 30 years who also filled out the State Trait Anxiety Inventory. A measure of alpha–delta anticorrelation showed trait-like properties being uniformly higher in high trait anxiety subjects independent of experimental manipulation. Contrariwise, delta–beta coupling appeared only in anxiogenic situation both in high and low anxiety subjects. © 2006 Elsevier B.V. All rights reserved. | Selected mapping (SLM) and partial transmit sequence ::: (PTS) are well-known techniques for peak-power reduction ::: in orthogonal frequency-division multiplexing (OFDM). We ::: derive a simplified maximum likelihood (ML) decoder for SLM ::: and PTS that operates without side information. This decoder ::: exploits the fact that the modulation symbols belong to a given ::: constellation and that the multiple signals generated by the PTS or ::: SLM processes are widely different in a Hamming distance sense. ::: Pairwise error probability (PEP) analysis suggests how SLM and ::: PTS vectors should be chosen. The decoder performs well over ::: additive white Gaussian noise (AWGN) channels, fading channels, ::: and amplifier nonlinearities. | eng_Latn | 5,455 |
ICI analysis for FRFT-OFDM systems in doubly selective fading channels | Frequency offset affects the performance of orthogonal frequency division multiplexing system. The FRFT based OFDM is considered in this article to minimize this affect. The expressions of signal to interference ratio (SIR) due to inter carrier interference (ICI) has been derived for frequency selective fading channel and doubly selective fading channels (Time frequency selective fading channels) for FRFT based OFDM system. The simulation analysis validate that FRFT based OFDM systems has superior SIR performances by choosing the optimal fractional factor than the standard OFDM system, for a large carrier offset exists in the system. | The author attempts to show how the generation and compression of complementary codes can be based on a specific single-input-multiple-output FIR (finite impulse response) digital filter structure. Driving this filter with a unit pulse yields both the code and its complement as the response simultaneously. A decoder is then derived as an FIR digital filter which is matched to the coder filter. The significance of this technique lies in the relative ease with which the decoder structure may be identified for arbitrary coder structures. This then leads to decoding algorithms with reduced computational requirements. An example is presented which shows how calculations on the order of N/sup 2/ may be reduced to a number on the order of Nlog/sub 2/N. > | eng_Latn | 5,456 |
Analytical Model for GNSS Receiver Implementation Losses | Global Navigation Satellite System (GNSS) receivers suffer signal-to-noise ratio (SNR) losses due to bandlimiting, quantization, and sampling. This paper presents an analytical model for GNSS receiver losses applicable to a wide variety of hardware configurations. The model addresses digitization of the received signal by a uniform quantizer with an arbitrary (even or odd) integer number of output levels. The model provides SNR loss values for GNSS signals in the presence of both additive white Gaussian noise and interference, provided that the interference can be accurately modeled as a non-white, Gaussian wide sense stationary process. | This paper addresses the problem of channel and propagation delay estimation in asynchronous DS/CDMA systems. We consider the uplink connection in DS/CDMA with long spreading codes. The MIMO stochastic gradient algorithm proposed in [6] is estimating a linear combination of the channel impulse responses and the propagation delays. This estimate suffices for the equalization purposes. The propagation delays are estimated with a simple matching scheme. | eng_Latn | 5,457 |
Cooperative trajectory planning for multi-UCAV using multiple traveling salesman problem | This paper studied the problem of cooperative trajectory planning integrated target assignment for multiple unmanned combat aerial vehicles, servicing multiple targets. The problem is formulated as a dynamics-constrained, multiple depot, multiple traveling salesman problem with neighborhoods (DC_MDMTSPN), which is a variant of the multiple traveling salesman problem (MTSP). Then, the entire process of solving the DC_MDMTSPN consists of two phases: 1) In the preprocessing phase, the directed graph is constructed and then the original problem is transformed to a standard asymmetric TSP (ATSP); 2) In the solving phase, the Lin-Kernighan Heuristic (LKH) searching algorithm is used to solve the ATSP. Finally, a typical scenario validates the proposed approach and experimental results demonstrate that the approach is feasible and effective. | AVS-M isthemostrecent videocodingstandard developed bytheAudioandVideoCodingStandard Workgroup ofChina(AVS), whichpromises improved performance close toH.264/AVC withlower complexity. Inthis paper, complexity isestimated formacroblockbased AVS-MJiben profile decoder based ontheoretical analysis andextensive experiments onageneral-purpose processor. Thetotal memoryrequired byAVS-Mdecoder ispresented first, thenthenumberofbasic operations consumedby keydecoding subfunction isusedto estimate thecomputational complexity. Finally, we presents complexity distribution ofthereference decoder based onextensive experiments. Theresults arevaluable forcomplexity estimation oftheAVS-M decoder realization andoptimization ontarget platforms. | eng_Latn | 5,458 |
Long noncoding RNAs: a potential novel class of cancer biomarkers | Long noncoding RNAs (lncRNAs) are a novel class of RNA molecules defined as transcripts longer than 200 nucleotides that lack protein coding potential. They constitute a major, but still poorly characterized part of human transcriptome, however evidence is growing that they are important regulatory molecules involved in various cellular processes. It is becoming increasingly clear that many lncRNAs are deregulated in cancer and some of them can be important drivers of malignant transformation. On the one hand, some lncRNAs can have highly specific expression in particular types of cancer making them a promising tool for diagnosis. The expression of other lncRNAs can correlate with different pathophysiological features of tumor growth and with patient survival, thus making them convenient biomarkers for prognosis. In this review we outline the current state of knowledge about the fast growing field of application of lncRNAs as tumor biomarkers. | In cloud radio access networks (C-RANs), the baseband processing of the available macro- or pico/femto-base stations (BSs) is migrated to control units, each of which manages a subset of BS antennas. The centralized information processing at the control units enables effective interference management. The main roadblock to the implementation of C-RANs hinges on the effective integration of the radio units, i.e., the BSs, with the backhaul network. This work first reviews in a unified way recent results on the application of advanced multiterminal, as opposed to standard point-to-point, backhaul compression techniques. The gains provided by multiterminal backhaul compression are then confirmed via extensive simulations based on standard cellular models. As an example, it is observed that multiterminal compression strategies provide performance gains of more than 60% for both the uplink and the downlink in terms of the celledge throughput. | eng_Latn | 5,459 |
Random Central Limit Theorem for Kernel Estimators of Density | Using the theory of character function,we derived the random central limit theorem for kernel estimators of density,then we obtained the convergence rate of central limit theorem by using the Berry-Esseen estimator.Moreover,we give two examples. | Based on the traditional adaptive multiuser detection method,sum up application of new LMS,RLS,Kalman arithmetics in DS-CDMA Multiuser detection.principles and methods of 3 arithmetics were given and emulation by Matlab.Based on comparing with SIR and errorcode of 3 arrthmetic,Kalman arithmetic show more excellent detection performance. | eng_Latn | 5,460 |
Mach-Zehnder Mode/Wavelength (De)Multiplexer for WDM/MDM Optical Transmission | We propose and experimentally demonstrate a low-loss and low-crosstalk Mach-Zehnder mode/wavelength multi/demultiplexer for WDM/MDM transmission. A broadband 3dB mode divider, which is also newly devised here, makes it possible to compose Mach-Zehnder filter for “mode” and “wavelength” simultaneously. | This paper studies the secure multiterminal source coding problem with actions. In particular, one main encoder observes an independent and identically distributed (i.i.d.) source Xn and wishes to compress this source lossyly to the decoder. Another encoder observes the source Yn and wants to compress this source losslessly to the decoder. A passive eavesdropper having access to the side information Zn can observe the information bits sent by the main encoder. In this scenario, the decoder is allowed to choose actions affecting the correlated source Yn and the side information Zn. For this problem, we characterize the optimal rate-distortion-cost-leakage region for a discrete memoryless setting. | eng_Latn | 5,461 |
1 MAC layer channel quality measurement in 802.11 | We present a novel technique for accurately estimating the proportions of packet losses arising from collisions and from other sources of loss (channel noise, hidden nodes etc). Our approach is robust, makes use of local station-level measurements and requires no message passing. The required measurements are available in standard hardware as they are required for CSMA/CA operation. No channel quality probing is required which ensures energy efficiency | Ultra wide band (UWB) impulse radio (IR) technology calls for robust and low-complexity receiver techniques. State-of-the-art proposals are both coherent ML receivers, noncoherent transmitted reference systems, or hybrid choices, all of which are derived from an AWGN model. In this paper we investigate an alternative technique which has been recently proposed, and which is based upon a Gaussian mixture (GM) model for multiple access interference. We show that this technique exhibits superior performance in comparison to AWGN receivers, and can be implemented with low-complexity. | eng_Latn | 5,462 |
Cutaneous color sensitivity: explanation and demonstration. | Past reports that humans can, in complete darkness, sense with their fingers the colors objects would have if illuminated, have understandably been received with skepticism. A previously proposed hypothesis, based on differential rate of absorption of infrared radiation by different layers of the skin, is inconsistent with the thermodynamics of the situation. Quantitative analysis of the system consisting of a roomtemperature surface juxtaposed to the higher temperature skin, however, leads to the conclusion that large differences in emissivity of different room-temperature surfaces almost certainly could be detected by the associated effects on skin temperature. Easily repeatable demonstrations show that this is true, and a few simple temperature measurements confirm the theoretical identification of the mechanism. | We consider a power control scheme for maximizing the information capacity of the uplink in single-cell multiuser communications with frequency-flat fading, under the assumption that the users attenuations are measured perfectly. Its main characteristics are that only one user transmits over the entire bandwidth at any particular time instant and that the users are allocated more power when their channels are good, and less when they are bad. Moreover, these features are independent of the statistics of the fading. Numerical results are presented for the case of single-path Rayleigh fading. We show that an increase in capacity over a perfectly-power controlled (Gaussian) channel can be achieved, especially if the number of users is large. By examining the bit error-rate with antipodal signalling, we show the inherent diversity in multiuser communications over fading channels. | eng_Latn | 5,463 |
Optimal damping in multilayer sandwich beams | We describe some possible models for a multilayer sandwich beam consisting of alternating stiff and compliant beam layers. The stiff layers are modeled under Euler-Bernoulli assumptions while the compliant layers essentially only carry the shear. We include viscous damping in the compliant layers and consider the optimization problem of choosing the damping parameteres for each layer so that the maximal asymptotic damping angle in the system eigenvalues is obtained. The solution is obtained analytically as a closed-form function of the various material parameters. | In this paper we develop closed-form approximations for the coded BER in bit-interleaved coded modulation (BICM) transmission over Rayleigh fading channels. To obtain the desired expressions we apply the so-called saddle point approximation and use analytical forms of the probability density functions (PDF) of the reliability metrics. Numerical examples illustrate the accuracy of the proposed method. | eng_Latn | 5,464 |
Regulation of receptor tyrosine kinases by miRNA: overexpression of miRNA using lentiviral inducible expression vectors. | MicroRNAs have the ability to alter and regulate multiple genes, including RTK family members, making them an attractive approach for molecular therapeutic development. We use a pCDNA6.2-EmGFP-microRNA expression vector to overexpress individual mature microRNA and then transfer the expression cassette into a single, inducible lentiviral vector (pINDUCER20). We successfully use this system to create a pINDUCER-EmGFP-miRNA27a expression vector and generate a stable head and neck cancer cell line (UM-SCC-22A) that inducibly expresses miRNA-27a, resulting in targeted epidermal growth factor receptor down regulation. In this chapter, we describe the protocol for engineering the pINDUCER-EmGFP-microRNA expression vector, producing lentiviral particles for target cell infection, and evaluating downregulation of gene expression. | In this paper, blind equalization of short burst signals is formulated with the twin support vector regressor (TSVR) framework. The proposed algorithm combine the conventional cost function of TSVR with classical error function applied to blind equalization: the Godard's error function that describes the relationship between the input signals and the desired output signals of a blind equalizer is contained in the penalty terms of TSVR, and the iterative re-weighted least square (IRWLS) algorithm is used for twin support vector regressor to achieve fast convergence. In addition, it utilizes the data-reusing method for small amounts of data samples to reach stable convergence. Simulation experiments for constant modulus signals are done to prove the feasibility and validity of the proposed algorithm. | eng_Latn | 5,465 |
Quasipotential equation in terms of rapidities and applications to relativistic bound-state and scattering problems | The review is devoted to an approach to the relativistic two-body problem in which a key role is played by the rapidity, the variable canonically conjugate to the relativistic relative distance. For a large class of quasipotentials, the analytic properties of the amplitude and wave function in the rapidity (energy) and orbital angular momentum are fully investigated. Several quantum-mechanical methods are generalized, giving the relativistic variable-phase method, a method for calculating the relativistic corrections, equations for the relativistic analogs of the scattering length and effective range, and a high-energy representation for the scattering amplitude, among others. | The design of the LTE physical layer (PHY) is heavily influenced by the requirements for high peak transmission rate (100 Mbps DL/50 Mbps UL), spectral efficiency and multiple channel bandwidths (1.25–20 MHz). Unfortunately, the existing WCDMA turbo interleaver does not permit an efficient high throughput implementation. That is why the 3rd Generation Partnership Project (3GPP) has proposed the quadratic polynomial permutation (QPP) interleaver to rectify this situation. In this paper, we will study the performances of QPP interleaver for LTE encoder channel for different configurations of LTE system and we study the effect of LTE channel turbo encoder for the transmission over a wireless multipath channel. | eng_Latn | 5,466 |
A Symbols Detection Algorithm of MIMO Systems Based on Information Propagation | Symbols detection algorithm of multiple-input multiple-output (MIMO) systems based on information propagation is proposed. First MMSE method is adopted for equalization then based on the equalized soft information, according to the signal-interference-noise ratio of the signal received by the antennas, taking individual receiving antenna as unit, the emission symbols are selected and further decided one by one. The result of each decision is propagated to all the following antennas to improve the performance. Theoretical analysis and computer simulation results show that this algorithm achieves better performance than minimum mean square error (MMSE) algorithm and in the case that the number of receiving antennas is not very large it is comparable to the classic Vertical Bell Labs Layered Space-Time (V-BLAST) algorithm. However, the computation complexity is much lower than V-BLAST. | In an earlier paper by the author the problem of determining the optimum symmetrical weighting factors for a video MTI radar was discussed. This paper extends this work so as to remove the symmetrical restriction from the problem. In addition, for a staggered pulse system, optimum times of transmission are determined. In the earlier paper a global solution to the restricted optimization problem was achieved. In this paper only a locally optimum solution is achieved for the more general problem. | kor_Hang | 5,467 |
Performance Analysis and Comparison of Various Channel Decoding Techniques | Channel encoding and decoding are performed to remove the influence of the channel on the transmitted data that result bits in error. Some redundant bits are added with the original data to mitigate the effect of error. Various channel coding/decoding techniques are used for error correction and detection. This paper presents the comparative analysis of various decoding techniques for the purpose of selecting the optimum technique for a particular application and fulfills the requirement of the system. | Abstract Many operations on strings of length n can be speeded up by a factor of p using p processors. String operations can also be speeded up, even when a single processor is used, by compactly encoding the strings, e.g. using run length code. This paper shows how to combine these two approaches by using p processors to process compactly encoded strings. | eng_Latn | 5,468 |
A hybrid method for wave propagation from a localized source, with application to mountain waves | Wave propagation from a localized source into a non-uniform medium is analysed using a hybrid method. This consists of an integral representation in the near-field and a numerical ray tracing in the far-field. The ray tracing includes the calculation of wave-action density and is initialized from the stationary-phase approximation to the near-field integral. The method is tested on the problem of mountain waves in a turning wind, as studied by Shutts. A ray calculation with rotation added to the Shutts model is also presented and is interpreted with a simple analytical model in which the horizontal divergence of rays balances the vertical convergence of rays. In the example presented here, the inclusion of rotation speeds up the approach to wave-breaking amplitudes. | MIMO-OFDM is a promising technique for broadband communications over mobile wireless channel. In this paper, we investigate the channel estimation problem for MIMO-OFDM systems. We proposed a novel EM (expectation maximization)-based channel estimation method. This proposed method employs the poly-nomial channel model along with the EM-based algorithm and makes a tradeoff between the computational complexity and the performance of estimation accuracy. Computer simulations show that, compared with the traditional EM-based channel estimation, the novel method has a great advantage of estimation accuracy. | eng_Latn | 5,469 |
Ankle Impingement: Combined Anterior and Posterior Impingement Syndrome of the Ankle | Background: Simultaneous anterior and posterior ankle impingement has not been previously reported. We identified 62 patients with both anterior and posterior impingement and report the results of ... | An OFDM system may be a good candidate for a next-generation wireless communication system which requires high-speed and high-rate data transmission. In OFDM systems, guard intervals are inserted to mitigate the effects of ISI (Inter-Symbol Interference). But guard interval insertion degrades the system performance from the standpoint of data rate and bandwidth efficiency. In this paper, a new method to improve the performance of an OFDM system without guard interval. First, PIC (Parallel Interference Cancellation) scheme which can reduce ISI by subtracting the estimated multi-path components from the received signal will be considered. And the proposed system with Pseudo-Decorrelator estimates transmitted signals by using the inverse matrix of cross-correlation matrix relating to interference components. The performance of the proposed system is evaluated through computer simulations and compared with that of the PIC system and an OFDM system without guard interval. | eng_Latn | 5,470 |
High Rate CPFSK Space-Time Trellis Codes | Space-time trellis coding is an established diversity technique that reduces the effects of multipath fading over wireless communication channels. Here, we consider high rate space-time trellis codes (STTC) with continuous phase frequency shift keying (CPFSK). We present optimized rate-2/3 STTC implemented with 3 transmit antennas. These codes provide system throughputs of 4 and 6 bits per channel use with 4-ary and 8-ary CPFSK respectively. Simulated error rate performance of the optimized codes with receive diversity is presented. We show that although the schemes do not achieve full transmit diversity, they provide excellent coding gains compared to full rank schemes that have equivalent throughput, but higher order modulations and greater complexity. | Key message ::: Physical interaction and phosphorylation by CaMPK9 protects the degradation of CaWRKY40 that induces resistance response in chickpea to Fusarium wilt disease by modulating the transcription of defense responsive genes. | eng_Latn | 5,471 |
Detection and Printability of Shifter Defects in Phase-Shifting Masks : Photolithography | Because of the high printability of shifter defects in phase-shifting masks, it is worthwhile to characterize the inspection and printing of the shifter defects. The detectability and printability of shifter defects as a function of size and location have been investigated by experiments and simulation. A test mask with various programmed shifter defects was inspected by means of a die-to-die inspection system and printed in positive resist with an i-line stepper. Corner defects are difficult to detect and have low printability. A defect located in small features has high printability. We have also investigated the detectability and printability of the phase angle defects which have phase angles other than 180°. Defects with 120° to 180° phase angles have high printability. Defects with phase angles below 90° are not printed. | Selected mapping (SLM) and partial transmit sequence ::: (PTS) are well-known techniques for peak-power reduction ::: in orthogonal frequency-division multiplexing (OFDM). We ::: derive a simplified maximum likelihood (ML) decoder for SLM ::: and PTS that operates without side information. This decoder ::: exploits the fact that the modulation symbols belong to a given ::: constellation and that the multiple signals generated by the PTS or ::: SLM processes are widely different in a Hamming distance sense. ::: Pairwise error probability (PEP) analysis suggests how SLM and ::: PTS vectors should be chosen. The decoder performs well over ::: additive white Gaussian noise (AWGN) channels, fading channels, ::: and amplifier nonlinearities. | eng_Latn | 5,472 |
Adaptive Power Allocation for Multihop Regenerative Relaying With Limited Feedback | A multihop regenerative relay system is considered. We explore adaptive power allocation (PA) under a total power constraint to minimize the system error probability when the perfect channel state information (CSI) is known at the transmitters. We propose adaptive PA schemes with limited feedback when the transmitters have no perfect knowledge of CSI. Simulation results demonstrate the good performance of the proposed PA scheme with perfect CSI. When no perfect CSI is available at the transmitters, the proposed PA schemes with a small number of feedback bits are able to achieve very close performance to the adaptive PA with perfect CSI. | This paper addresses the problem of channel and propagation delay estimation in asynchronous DS/CDMA systems. We consider the uplink connection in DS/CDMA with long spreading codes. The MIMO stochastic gradient algorithm proposed in [6] is estimating a linear combination of the channel impulse responses and the propagation delays. This estimate suffices for the equalization purposes. The propagation delays are estimated with a simple matching scheme. | eng_Latn | 5,473 |
A Study on The Capacity of Massive MIMO System with The Aid of MATLAB Simulink | Today’s main focus of the emerging cellular technologies is to fulfill users high demand while fully utilizing available resources. Massive MIMO is expected to play a vital role in this development, such as 5G, as it results in noticeably better performance, against the cost of needing more hardware components. This work study the effect of increasing the number of antennas on the system data-rate (capacity). We derive this relationship mathematically for both Single Input Single Output (SISO) and MIMO systems. Further, different from other papers in literature, using MATLAB Simulink we verify this proportionality for three modulation schemes (QPSK, 16 QAM and 64 QAM) and for several MIMO (2x2 and 4x4) and Massive MIMO (8x8, 16x16 and 24x24) systems. We finally establish a comparison between that theoretical results and results obtained from MATLAB Simulink. | This paper deals with the problem of state estimation for perturbed output nonlinear systems. A multiple models approach is used to describe such class of systems. Then a structure of Lyapunov based sliding mode multiple observer is presented. The stability proof of the observer is ensured by a suitable choice of estimation gains which are solutions of a set Linear Matrix Inequalities(LMI). The simulation results for the denitrification application demonstrate the effectiveness of the developed estimator scheme. | eng_Latn | 5,474 |
An efficient encoder for distributed real-time applications | Standard basic encoding rules are too elaborate and inefficient for distributed real-time applications. Two major obstacles encountered are long protocol data units and slow encoding times. The problem of encoding for real-time applications is addressed. Taking Fieldbus as a representative of real-time networks, it is shown why the encoder should be simplified and how this can be done. The impact of encoders, in general, on the overall network performance is studied. Implementation results demonstrate the efficiency of the proposed encoder. > | We present a symbol synchronization scheme using wavelets that completely eliminates the pattern-dependent jitter. This is achieved by obtaining the optimal pre-filter using a particular linear combination of the wavelet and its translates. We further investigate synchronization schemes for the case where both the scaling function and wavelet are used simultaneously as shaping pulses for modulation, and explicit expressions for the variance of the timing jitter in the tracking mode are derived. The results are then generalized to the case where shaping pulses are produced by splitting the spectrum of a shift orthogonal function. | eng_Latn | 5,475 |
Performance impact of pilot tone randomization to mitigate OFDM jamming attacks | Orthogonal Frequency Division Multiplexing (OFDM) uses pilot tones to estimate and equalize the channel's frequency response whose locations and values are known. This makes OFDM prone to pilot tone based jamming attacks. Our previous research analyzed such jamming attacks. This paper builds on this idea and proposes approaches to mitigate the effect by randomizing pilot tone locations. It also presents OFDM channel and equalizer model, formulates channel estimation error, and then undertakes an analysis of OFDM system for randomized pilot tones, verifying through simulation. Both analytics and simulation show that randomized pilot tone schemes perform worse when a jammer is not present but perform better in the presence of pilot tone based jammer. Of the two proposed randomization schemes, the one that constrains the distance between random tones performs better in both scenarios. | In an earlier paper by the author the problem of determining the optimum symmetrical weighting factors for a video MTI radar was discussed. This paper extends this work so as to remove the symmetrical restriction from the problem. In addition, for a staggered pulse system, optimum times of transmission are determined. In the earlier paper a global solution to the restricted optimization problem was achieved. In this paper only a locally optimum solution is achieved for the more general problem. | eng_Latn | 5,476 |
Practicalities of Learning Modules Course of Culinary Nutrition Problem Oriented Lazy Learning (PBL) Nutrition for Students in the Stikes Perintis Padang | learning modules oriented Problem Based Learning (PBL) is a module that can increase the activity of learning to train students to find authentic problems, gather information to solve the problem. This study aims to produce learning modules Oriented Problem Based Learning (PBL) is valid, practical and effective.kind This study uses research and development Research and Development (R & D) to develop four model-D (4D). The development phase is 4D Define (define), Design (design), Development (development) and disseminate (dissemination). Data were obtained from the test, the practicalities, the practicality of data obtained from the questionnaire practicalities of faculty and students. Test the practicalities of the module-oriented Problem Based Learning subjects Culinary Association of Lecturers and students questionnaire shows (very practical) to the achievement of 92.5% and 89.23%. | Selected mapping (SLM) and partial transmit sequence ::: (PTS) are well-known techniques for peak-power reduction ::: in orthogonal frequency-division multiplexing (OFDM). We ::: derive a simplified maximum likelihood (ML) decoder for SLM ::: and PTS that operates without side information. This decoder ::: exploits the fact that the modulation symbols belong to a given ::: constellation and that the multiple signals generated by the PTS or ::: SLM processes are widely different in a Hamming distance sense. ::: Pairwise error probability (PEP) analysis suggests how SLM and ::: PTS vectors should be chosen. The decoder performs well over ::: additive white Gaussian noise (AWGN) channels, fading channels, ::: and amplifier nonlinearities. | eng_Latn | 5,477 |
A joint error correction and ICI cancellation algorithm for OFDM systems | Orthogonal Frequency Division Multiplexing (OFDM) is a spectrally efficient and robust digital communication technique adopted by the newly developed Wireless Communication standards. Frequency offset errors due to Doppler shifts disturbs the alignment of the orthogonal subcarriers and causes them to overlap with each other which results in Inter Carrier Interference (ICI). This paper proposes the use of channel estimation for ICI cancellation. The channel frequency response at pilot subcarriers is estimated by using Least Square (LS) estimator. Along with this the (23, 12, 7) Golay Code has been employed in order to further improve the Bit Error Rate (BER) performance of the system. Simulation of the proposed OFDM system is carried out for Stanford University Interim (SUI) Channel model 6 in the existence of Additive White Gaussian Noise (AWGN). | Abstract A numerical scheme, based upon the Kobayashi-Tranter method with certain modifications, is given for axisymmetric punch and crack problems in elasticity. The problems are reduced to solving a system of linear algebraic equations instead of a Fredholm integral equation of the second kind. A standard program thus allows the treatment of a range of different cases. The indentation of a rigid punch on an elastic layer overlying an elastic foundation is formulated in this fashion and numerical results for various cases are presented. | eng_Latn | 5,478 |
Self-Coherent Systems for Short Reach Transmission | We review self-coherent receiver schemes that enable >100 Gb/s per-wavelength transmission over ∼100 km of fiber. We discuss in detail recent progress on Kramers-Kronig receivers. | *† This paper presents a new technique to design a col lision avoidance maneuver when a conjunction analysis indicates that the probability of collision is above a certain threshold. This technique makes use of the Aerospace Corporation designed NLP2 algorithm to numerically design a minimal delta-V maneuver to reduce the probability of collision below the threshold of concern as well as optionally meet ing a miss distance constraint. In addition, the algorithm can consider uncertainties in the con juncting objects’ covariances, either individually or jointly, as part of the objective p robability. The algorithm is fast, robust, and highly tunable. This technique has been prototyped for analysis. Experimental results and conclusions about the algorithm and collision avoid ance in general are also given. | eng_Latn | 5,479 |
A study on SNR estimation algorithms for channel state estimation in Communication Satellite Systems employing Fade Mitigation Techniques | Channel state estimation is one of the key processes carried out at the physical layer of Satellite Systems employing Fade Mitigation Techniques such as Adaptive Coding and Modulation ACM. An accurate and reliable channel estimate is needed to fully realize the capacity gains accrued by using ACM. In this paper the SNR estimation algorithms, which perform the role of channel state estimators, are analysed from a system point of view to get a quantitative idea on the number of received symbols needed to get a reliable estimate, and the impact of interference noise on it. A DVB type satellite system has been investigated for the study. An improvement over the Maximum Likelihood ML estimator using Bayesian principles is suggested and illustrated. | Rapid transfer alignment has strict demands for filtering accuracy and convergent velocity,but alignment accuracy is seriously degraded if there exist outliers in measurements.A novel approach to reject outliers is proposed,a small sequence sampled online makes up of a new sequence by forward symmetry extension,which is processed by wavelet threshold de-noising,then outliers can be detected,new measurements made up of previous measurements act as current inputs of Kalman filter,the degradation caused by outlier is removed,accuracy of filtering system obtained for the demand of transfer alignment. | eng_Latn | 5,480 |
Residue-residue contacts: application to analysis of secondary structure interactions. | Protein structures and their complexes are formed and stabilized by interactions, both inside and outside of the protein. Analysis of such interactions helps in understanding different levels of structures (secondary, super-secondary, and oligomeric states). It can also assist molecular biologists in understanding structural consequences of modifying proteins and/or ligands. In this chapter, our definition of atom-atom and residue-residue contacts is described and applied to analysis of protein-protein interactions in dimeric β-sandwich proteins. | We assume a CDMA downlink multiuser scenario, where the base station is equipped with multiple transmit antennas, and each user has multiple receive antennas. For this setup we propose a new, computationally effective MIMO multiuser detector for frequency selective channels. We exploit the fact that the interference mainly comes from the spatial domain, while the residual interference is due to temporal dispersion and multiuser interference. This motivates us to suppress the residual interference in a linear fashion, while combating the spatial interference iteratively. This approach is an efficient performance-complexity tradeoff between fully iterative and linear detectors. | eng_Latn | 5,481 |
Exact Solitary Wave Solutions for a Class of BBM Systems | Exact solitary wave solutions for a class of strongly coupled BBM systems are investigated.To find an explicit solitary wave solution of the system,it is sufficient to find a solution of an ordinary differential equation.For a specified form of solutions,the solution of the ordinary differential equation can be found by solving a system of nonlinear algebraic equations.By means of hyperbolic function method,and by detailed computation,the exact solitary wave solutions of the system are presented. | Based on the traditional adaptive multiuser detection method,sum up application of new LMS,RLS,Kalman arithmetics in DS-CDMA Multiuser detection.principles and methods of 3 arithmetics were given and emulation by Matlab.Based on comparing with SIR and errorcode of 3 arrthmetic,Kalman arithmetic show more excellent detection performance. | eng_Latn | 5,482 |
Comparing two linguistic phenomena of peacock spreading its tail and the head of lion with its small tail from the Perspective of Thinking Mode | This paper,describing two natural phenomena of peacock spreading its tail and the head of lion with its small tail,explores these two equivalent linguistic phenomena from the perspective of thinking mode. | Selected mapping (SLM) and partial transmit sequence ::: (PTS) are well-known techniques for peak-power reduction ::: in orthogonal frequency-division multiplexing (OFDM). We ::: derive a simplified maximum likelihood (ML) decoder for SLM ::: and PTS that operates without side information. This decoder ::: exploits the fact that the modulation symbols belong to a given ::: constellation and that the multiple signals generated by the PTS or ::: SLM processes are widely different in a Hamming distance sense. ::: Pairwise error probability (PEP) analysis suggests how SLM and ::: PTS vectors should be chosen. The decoder performs well over ::: additive white Gaussian noise (AWGN) channels, fading channels, ::: and amplifier nonlinearities. | eng_Latn | 5,483 |
The mutual coherence of simultaneously injection-locked laser diode arrays | The modulus of the mutual coherence function, {vert bar}g{sub 12}({tau}){vert bar}, has been measured for two physically separated laser diode arrays that were simultaneously injection locked to the same master laser. The measured value {vert bar}g{sub 12}({tau}){vert bar} = 0.96 {plus minus} 0.06, is close to ideal. 2 figs. | We present a practical coded cooperative jamming scheme for the problem of secure communications over the two-way wiretap channel. We design low-density parity-check (LDPC) based codes whose codewords interfere at the eavesdropper's terminal, thus providing secrecy. We show that our scheme can guarantee low information leakage rate, and we assess its precise performance for classical and spatially coupled LDPC codes. | eng_Latn | 5,484 |
SIZE-INDUCED DIFFUSE PHASE TRANSITION IN THE NANOCRYSTALLINE FERROELECTRICPBTIO3 | We report a detailed study of the size dependence of the ferroelectric transition in an ensemble of ${\mathrm{PbTiO}}_{3}$ nanoparticles produced by coprecipitation. The phase transition was monitored by dielectric measurements, variable temperature x-ray diffraction, and differential scanning calorimetry (DSC). Size effects were found to become important only below \ensuremath{\approxeq}100 nm (coherently diffracting x-ray domain size). The tetragonal distortion of the unit cell (which is related to the spontaneous polarization) decreases exponentially with size and vanishes at 7 nm. The ${\mathit{T}}_{\mathit{c}}$ decreases gradually but the transition becomes increasingly diffuse with a decrease in the size from 80 to 30 nm, below which there is no peak in the dielectric constant or the heat flow (DSC), though ferroelectric ordering probably persists down to \ensuremath{\approxeq}7 nm. | In soliton communication systems, the continuous nonlinear spectrum, ideally zero, is conventionally ignored at the receiver. In this paper, we exploit correlation between the received continuous spectrum and perturbations of the discrete soliton eigenvalue. We propose four estimation schemes, classified into two categories, one based on the nonlinear Fourier transform (NFT) and the other based on minimum Euclidean distance. Both categories comprise two schemes, one that exploits the received continuous spectral function to achieve improved estimation and one that does not. Numerical simulations demonstrate that significant reduction in estimation error can be achieved when the continuous spectrum is exploited, translating into improved information transmission rates of up to ${\text{46}}\%$ compared to the reference NFT-based scheme. | yue_Hant | 5,485 |
A downlink multi-stream modulation coding mode selection and power load method | This invention relates to a method for selecting down multi-flow modulation coding mode and loading power including the following steps: under the mode of single-user MIMO, the maximum data-flow of channel quality identification selects a modulation code mode of the flow according to its channel quality identification value and the rest MIMO data flow selects a lower stage modulation coding mode so as to reduce feedback of channel quality and keep better performance of throughput, in which, when the SINR of a best flow is greater than the maximum SINR in the modulation code mode, a base station applies a method of loading to power and redundant power will be transferred to the rest to increase the throughput. | The way to renovate the inlet/outlet differential pressure interlock protection on the boiler circulating water pump of 300 MW unit in Mawan Power Plant was discussed,as well as the effect of usage. Some approaches to extend the usage of DCS were provided. | eng_Latn | 5,486 |
Two-stage interference-resistant adaptive periodically time-varying CMA blind equalization | We consider the problem of blindly equalizing a digital communication signal distorted by a linear time-invariant channel and contaminated by severe co-channel or adjacent-channel digital interference under the assumption that the latter exhibits a different symbol rate from the desired signal. The proposed equalizer is composed of two stages that are both periodically time-varying (PTV) in order to better match the periodical statistics of the received signal. The first stage employs linear PTV filtering to mitigate interference, thus allowing the second stage, based on the constant modulus algorithm (CMA), to reliably recover the transmitted information symbols. Computer simulations confirm the effectiveness of the new approach, and comparisons with existing blind methods show that a significant performance gain can be attained. | Abstract Asymmetric total synthesis of small ring macrolide stagonolide-E has been described in this communication. The main highlight of our synthetic strategy is the application of ME-DKR (metal enzyme combo dynamic kinetic resolution) reaction, asymmetric reduction with Noyori’s BINAL-H reagent system, stereoselective cross metathesis, and RCM (ring closing metathesis) reaction at a late stage enables us to achieve the synthesis of the target molecule in an efficient way. | eng_Latn | 5,487 |
Study of turbulent characteristics of flow around island in a braided river model using quadrant technique | AbstractTurbulent flow characteristics around the braid bar are not thoroughly studied till now. In the current paper, the quadrant method is used to analyze the turbulence characteristics of flow around the island in a braided river model. An attempt has been made herein to relate the depositional characteristics around the island in the braided river model to the sweep and ejection events. The new parameter bursting ratio is defined in this paper; it is observed that the bursting ratio is strongly related with the erosion/deposition characteristics around the island in a braided river model. The transition probability of 16 possible bursting movements are computed for four different experimental condition, the results shows that the, movements are closely related with the erosion/deposition magnitude around the bar in a braided river model. The values of sweep ratio and ejection ratio at 12 different points around the island for four different experimental conditions are computed using Box Cox analysis.... | We consider the throughput performance of ARQ in interfering channels, where the signal of interest as well as the interferers are subject to independent distributed Nakagami-m block fading. The key contribution is the derivation of closedform expressions for the rate-maximized throughput. For this purpose, we employ the powerful parameterization approach from [1], allowing the problem to be solved exactly in a closedform. We also consider the scaled-power, and the interferencelimited, case. | eng_Latn | 5,488 |
On the Shannon cipher system with a wiretapper guessing subject to distortion and reliability requirements | We modify the problem studied by Merhav and Arikan (see IEEE Trans. Inform. Theory, vol.45, no.6, p.1860-6, 1999) of discrete memoryless source encrypted messages guessing by wiretapper within given distortion level /spl Delta/ in the case of Shannon cipher system. The security of the system is measured by the expected number of guesses of a wiretapper needed for the reconstruction of the source messages on the base of cryptograms. The main modification is consideration of the distortion and reliability criteria and of possibility to limit the number of guesses. | In this paper, a new method is proposed to adaptively estimate the number of transmit antennas in cognitive radios and surveillance systems. It employs Schur complement to test the linearly independence of the new coming data with the previous data set. ?2 test is conducted based on the statistics of Schur complement variable. Last, Monte Carlo simulation is employed to test the performance of the estimator under different scenarios. | eng_Latn | 5,489 |
Novel EM-Based Channel Estimation Algorithm for MIMO-OFDM Systems | MIMO-OFDM is a promising technique for broadband communications over mobile wireless channel. In this paper, we investigate the channel estimation problem for MIMO-OFDM systems. We proposed a novel EM (expectation maximization)-based channel estimation method. This proposed method employs the poly-nomial channel model along with the EM-based algorithm and makes a tradeoff between the computational complexity and the performance of estimation accuracy. Computer simulations show that, compared with the traditional EM-based channel estimation, the novel method has a great advantage of estimation accuracy. | In this article we describe a global design approach of an X-band Tx/Rx module which, by means of a Multi Chip Module (MCM) technique, includes in a single package the different microwave functions (4-bit phase-shifter, low-noise amplifier, power amplifier, switching control circuits), the thin film interconnections, the bias circuits, the driver circuits (Si ICs) and the switching MOS. | eng_Latn | 5,490 |
Stochastic analysis of stereo quantization error | The probability density function of the range estimation error and the expected value of the range error magnitude are derived in terms of the various design parameters of a stereo imaging system. In addition, the relative range error is proposed as a better way of quantifying the range resolution of a stereo imaging system than the percent range error when the depths in the scene lie within a narrow range. > | We assume a CDMA downlink multiuser scenario, where the base station is equipped with multiple transmit antennas, and each user has multiple receive antennas. For this setup we propose a new, computationally effective MIMO multiuser detector for frequency selective channels. We exploit the fact that the interference mainly comes from the spatial domain, while the residual interference is due to temporal dispersion and multiuser interference. This motivates us to suppress the residual interference in a linear fashion, while combating the spatial interference iteratively. This approach is an efficient performance-complexity tradeoff between fully iterative and linear detectors. | eng_Latn | 5,491 |
Time-Reversal Methods in Acousto-Elastodynamics | The aim of the article is to solve an inverse problem in order to determine the presence and some properties of an elastic “inclusion” (an unknown object, characterized by elastic properties discriminant from the surrounding medium) from partial observations of acoustic waves, scattered by the inclusion. The method will require developing techniques based on Time Reversal methods. A finite element method based on acousto-elastodynamics equations will be derived and used to solve the inverse problem. Our approach will be applied to configurations modeling breast cancer detection, using simulated ultrasound waves. | In this paper we study the performance of IEEE 802.11e enhanced distributed channel access (EDCA) priority schemes under finite load and error-prone channel. We introduce a multi-dimensional Markov Chain model that includes all the mandatory differentiation mechanisms of the standard: QoS parameters, CWMIN, CWMAX arbitration inter-frame space (AIFS), and the virtual collision handler. The model faithfully represents the functionality of the EDCA access mechanisms, including lesser known details of the standard such as the management of the backoff counter which is technically different from the one used in the legacy DCF. We study the priority schemes under both finite load and saturation conditions. Our analysis also takes into consideration channel conditions. | eng_Latn | 5,492 |
MMSE multiuser detection for noncoherent non-orthogonal multipulse modulation | We present the minimum mean squared error multiuser detector for noncoherent detection of non-orthogonal multipulse modulation. The detector is analyzed in the large signal-to-noise ratio regime and it is shown that the MMSE detector approaches a new multiple access interference suppressing detector, termed the multipulse decorrelating (MD) detector. The asymptotic performance of the detectors is presented for the additive white Gaussian noise noncoherent channel. | In order to compute an optimal Kernel probability density function estimator (KDE), the plug-in method is considered in this paper. Such algorithm gives a way to optimize both the kernel and the bandwidth. Here, we propose a new procedure witch is faster than the common plug-in one. For each time, a factor J(f), which is linked to the second order derivative of the pdf, is analytically approximated. The pdf is estimated only once at the end of iterations. Different random variables with difficult distributions are generated in order to prove the efficiency of the proposed optimal estimator. These algorithms are then, applied to genetics data in order to give a better characterisation in the mean of neutrality of a given population by using the fast MISE optimal pdf estimation of the Tajima's D criterion. This criterion is a statistic allowing the estimation of the genetic neutrality of the sample population. | eng_Latn | 5,493 |
Two Dimensional Wavelet Transform Model for OFDM System | In this paper, a proposed structure was suggested by replacing the blocks of the fast Haar Wavelet Transform (WT) with a two dimensional wavelet transform at the transmitter and the receiver sides in the Orthogonal Frequency Division Multiplexing (OFDM) model. This can be done by converting a 1-Dimensional vector into a 2-Dimensional matrix and process it by 2-Dimensional Wavelet Transform (2D-WT). The proposed method was applied on the OFDM in Additive White Gaussian Noise (AWGN) and flat fading channel. It was concluded that the proposed method gives much better Bit Error Rate (BER) performance than the conventional OFDM model based on WT. The simulation results showed that the proposd structure outperforms the other scheme in the carried tests at the AWGN and flat fading channels. | A weightedL2 norm is introduced in which Markov operators, e.g., associated with noisy maps, are contracting provided the kernel (i.e., the transitional distribution) is smooth enough. This results in strong relaxational properties of noisy maps. Similar to this norm, integral functionals appear useful when studying spatiotemporal chaos and random fields. | yue_Hant | 5,494 |
Mean-square consensus of discrete-time multi-agent systems with Markovian switching topologies and persistent disturbances | This article deals with the leader-following mean-square consensus problem of discrete-time general linear multi-agent systems with Markovian switching topologies and persistent disturbances. Assume that the communication topology is not connected at any time but the union topology is connected. First, the estimators are designed to calculate the states of agents when external disturbance not exists. Based on the error information between the truth-values and estimated-values of states, the compensators are proposed to subject to the effect of persistent disturbances. And then, a new mean-square consensus control protocol is proposed for each agent. Second, by using the property of permutation matrix, the original closed-loop system is transferred into an equivalent system. Third, sufficient conditions for mean-square consensus are obtained in the form of matrix inequalities. Finally, numerical simulations are given to illustrate the effectiveness of the theoretical results. | The point process, a sequence of random univariate random variables derived from correlated ::: bivariate random variables as modeled by Arnold and Strauss, has been examined. Statistical ::: properties of the time intervals between the points as well as the probability distributions of the ::: number of points registered in a finite interval have been analyzed specifically in function of the ::: coefficient of correlation. The results have been applied to binary detection and to the transmission ::: of information. Both the probability of error and the cut-off rate have been bounded. Several ::: simulations have been generated to illustrate the theoretical results. | eng_Latn | 5,495 |
High rate single substrate polymer etching for multi- chip-modules (MCM) and off-chip-interconnect applications | Abstract The paper reports on work performed on MCM technology using polyimide as dielectric material which is being patterned by means of a dry etching technique. The main requirements for the patterning step are high rate and steep profiles. This can be achieved using low frequency plasma generation (25 kHz) which results in a fast and highly anisotropic etch with good selectivities towards the masking material. Chromium, copper and spin-on-glass have been looked at as masking materials. Results obtained show aspect ratios greater than 20:1 and clean surfaces making the technique suited for MCM's. | MIMO-OFDM is a promising technique for broadband communications over mobile wireless channel. In this paper, we investigate the channel estimation problem for MIMO-OFDM systems. We proposed a novel EM (expectation maximization)-based channel estimation method. This proposed method employs the poly-nomial channel model along with the EM-based algorithm and makes a tradeoff between the computational complexity and the performance of estimation accuracy. Computer simulations show that, compared with the traditional EM-based channel estimation, the novel method has a great advantage of estimation accuracy. | eng_Latn | 5,496 |
N‐Dimensional Partially Coherent Detection of an Accelerating Source | This article contains a discussion of correlation detection in which the coherent processing interval is limited by source/receiver accelerations and/or medium instabilities. A method is described, which, in effect, computes an n‐dimensional correlation function uniquely related to target trajectory. Groups of relatively short waveforms that are individually insensitive to source accelerations, etc., are, after coherent reception, combined via pattern‐recognition techniques. Curves are presented that give the processing gain of the method for various conditions. A numerical example is given for the sonar case. | We introduce in this paper a carrier phase detector suited to transmissions at very low signal to noise ratio. Based on the soft decoding of parity check equations, the synchronization scheme proposed here for a QPSK modulation outperforms a classical decision directed algorithm over a Gaussian channel, and is notably well adapted to satellite applications. | eng_Latn | 5,497 |
Recent Developments on Rational Approximation | As a special case of nonlinear approximation, approximation by rational functions (we call it rational approximation usually) has its important significance in both practice and application, and becomes a vital research field in approximation theory. | The performance of a pragmatic carrier phase estimation algorithm is evaluated over a range of SNRs. The optimal SNR regions for MQAM are compared to an AWGN channel observing gains of up to 40% in throughput. | eng_Latn | 5,498 |
Structural Models of Poly(cyclopentadithiophene-alt-benzothiadiazole) with Branched Side Chains: Impact of a Single Fluorine Atom on the Crystal Structure and Polymorphism of a Conjugated Polymer | This study describes the impact of a single fluorine atom substitution in the conjugated backbone of poly(cyclopentadithiophene-alt-benzothiadiazole) on the structure and the polymorphism of the polymer bearing 2-ethylhexyl side chains. Controlled growth of the nonfluorinated and fluorinated polymers by solvent vapor annealing (SVA), melt-crystallization on oriented poly(tetrafluoroethylene), and high-temperature rubbing yield highly crystalline and/or oriented films of a thermodynamically stable polymorph called form I. The single-crystal hk0 and the oriented fiber patterns are obtained in films prepared by SVA and aligned films, respectively. Form I involves a high-symmetry packing of four chains in an orthorhombic cell (Pccn space group) with pseudohexagonal symmetry. The chains are paired into dimers with a 3.6–3.8 A interchain π-stacking distance and a segregated mode of stacking of cyclopentadithiophene and benzothiadiazole (BT). A single H/F substitution on the BT unit modifies the orientation of t... | Without a cyclic prefix (CP), most single-carrier (SC) transmissions can not adopt frequency-domain equalizer (FDE) directly. This work utilizes frequency-domain channel estimator (FD-CE) and decision-feedback aliasing canceller (DF-AC) to produce single-FFT SC-FDE. In this way, non-CP single-carrier block transmission (SCBT) can be decoded using sphere decoder of MIMO-OFDM modems to support multimode and backward compatibility under an acceptable complexity in IEEE 802.11 very high throughput (VHT). An iV-point FFT is sufficient to measure channel frequency responses (CFR) from .L-sample preambles (L ≤ JV/2). And then, M-bit block codes (M ≤ L) are decodable over frequency domains with DF-AC's help. Simulations and measurements imply that this work can ensure adequate performance, even if there is no CP existed against the distortions of multipath propagation. | eng_Latn | 5,499 |
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