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Investigation of nonlinear orthogonal signal correction algorithm and its effects on multivariate calibration | The aim of this paper is to develop a nonlinear orthogonal signal correction (OSC) algorithm using kernel-based technique, termed as kernel OSC (KOSC), and investigate its effects on multivariate calibration. As a nonlinear data pretreatment, the proposed KOSC method can better analyze the nonlinear relationships between descriptor and response variables and remove from process measurement those undesirable variations not correlated with process property from a nonlinear point of view, which well prepares the corrected process trajectory for the subsequent calibration modeling. Two data sets are employed in illustration experiment. It is found that nonlinear OSC plus nonlinear calibration algorithm seems to have the superiority over other methods to improve the interpretation ability of regression model when process data nonlinearly vary with quality. | Abstract. One of the goals, in the context of nonparametric regression by smoothing spline functions, is to choose the optimal value for the smoothing parameter. In this paper, we deal with the cross validation method(CV), as a performance criteria for smoothing parameter selection. First, we implement a CV-based algorithm, in Matlab 6.5 medium and we apply it on a test function, in order to emphase the quality of the fitting by the CV-smoothing spline function. Then, we fit some real data with this kind of function. | eng_Latn | 28,900 |
Simulation of Nonlinearity Correction of Cylindrical Piezoelectric Scanner | A new modeling method based on sample data is described in this paper,through physics and sample date analysis on displacement vs.voltage characteristics of x-y plane of cylindrical piezoelectric scanner used in scanning probe microscope(SPM).Through sample data statistical analysis,and considering the error factors such as scan speed,scan angle,nonlinearity and coupling,a model represented by a binomial plus some error expressions is constructed.A nonlinearity correction expression based on the model is deduced.With the software Matlab this nonlinearity correction is simulated.The result of simulation indicates that it can eliminate the errors effectively.The ascendency of the method is that there are no polarization mechanism analysis and fewer number of model parameters.The method is practical applied to engineering. | Nowadays, finite Time stability of systems is popular for control engineering designers. In this paper, two control inputs will be designed for a typical high order system with using of Nonsingular Terminal Sliding Mode Control (NTSMC) and Back-Stepping methods, which clearly and completely remove chattering phenomena, also as finite time cause system stability. The control inputs are robust against of disturbance and uncertainties. The high order system that is used in this paper is a general sample and the most systems are compatible on it. | eng_Latn | 28,901 |
Performance comparison of three multi-objective optimization algorithms on calibration of hydrological model | In this essay, the comparison of three multi-objective optimization approaches MOPSO, NSGA-II and MOSCEM-UA has been carried out in the auto calibration of hydrological model- Hymod. By carrying out the calibration on two objectives of high flow and low flow objective functions, the Pareto front can be drawn. The performance of the three optimization algorithms is analyzed depending on three criterions that are the optimization time cost, Pareto front spacing rate and the dominating rate. Through analyzing the comparison results of MOSCEM-UA and NSGA-II with MOPSO method, the performance of convergence rate, Pareto non-dominant spacing rate and iteration speed are ideally expected. The simulation result with MOPSO algorithm is reasonable in the high flow and low flow process. The prediction area drawn from the optimization result indicates the reliability of the model. Meanwhile, the model uncertainty is also discussed to some extent. | 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 | 28,902 |
All-in-one measurement setup for fast and accurate linear characterization of guided-wave optical devices | We present an all-in-one, computer-controlled, measurement setup able to evaluate propagation losses, effective group index, and mode size of integrated optical devices and optical fibers. The possibility to use a single setup, instead of three separate ones, enables faster measurements, improvements in terms of reproducibility and precision, and reduction of systematic errors. Control of the operating conditions, easier system upgrade besides cost and laboratory space savings are other additional features of this system. To confirm proper operation and versatility of the proposed setup, different samples are successfully characterized, and results are presented and discussed. | The invention discloses a determining method of alignment precision. The determining method comprises the following step of determining the offset of alignment marks formed in the same preset region of a current membrane layer on a target substrate relative to any one membrane layer under the current membrane layer according to positions of multiple alignment marks formed on the target substrate; determining the alignment precision of the current membrane layer according to the offset and a preset rule. According to the determining method of the alignment precision, provided by the embodiment of the invention, the alignment offset between two optional layers can be obtained, and meanwhile, whether the alignment precision among three layers or more than three layers meet the production demands or not can be monitored; moreover, the alignment offset directions and the quality degree among multiple alignment layers can be directly seen through eyes. | eng_Latn | 28,903 |
Stage system calibration method, stage system and lithographic apparatus comprising such stage system | PURPOSE: A stage system calibration method is provided to accurately perform horizontal calibration by not making a noise and a horizontal scanning effect sensitive. CONSTITUTION: A stage is moved in order to move sensor heads about an encoder grid or to move an encoder grid about sensor heads. During the moving step, a position of the stage is measured through the encoder grid and the sensor heads. A vertical position data map is determined from sensor head output signals of the sensor heads(SH1,SH2). A horizontal position data map is calculated from the vertical position data map. An encoder position measuring system is calibrated based on the calculated horizontal position data map. | This paper covers a batch plate local stability checking method.The method is used in grab shipunloader parameterized design and the comparison of the results and the ones from overseas shows that the method is correct and practical. | eng_Latn | 28,904 |
Lighting unit having an anti-pollution device of optical components, and a photolithography apparatus comprising such an illumination unit. | Disclosed are a display apparatus and an exposure apparatus for use in such a device which unit comprises an illumination housing (LH), in which a radiation source (LA) and at least one reflector (RL) are arranged. In order to avoid that it is provided with means (LA, SH, L29), which prevent that in itself within the illumination housing, the optical components are forming a diffuse deposits from them containing particles of silicon contained in the surrounding air decreases, this is this home delivered radiation output by the illumination housing . | In this paper, robust actuator fault reconstruction for satellite attitude control systems (ACSs) in the presence of space environmental disturbances and actuator faults is investigated via a learning observer (LO). First, a nonlinear mathematical model of the satellite ACS satisfying Lipschitz constraint is established; then an LO is constructed to achieve robust reconstruction of satellite attitude angles, attitude angler velocities and actuator faults at the same time. Further, sufficient conditions for the robust stability of the LO are explicitly provided in this paper. The design problem of the proposed LO is formulated into a convex optimization problem in terms of linear matrix inequalities (LMIs) that can be directly solved using the LMI toolbox of MATLAB. At last, simulation studies on a satellite example are performed to illustrate the effectiveness and applicability of the presented LO-based fault-reconstructing strategy. | eng_Latn | 28,905 |
Method and apparatus for adjusting a position and / or speed measurement device | In order to adjust the distance between a measuring graduation and a scanning unit (7) of a position and / or speed measurement device is said spacer member (7) disposed together with a flat coil (3) on a support (8) in the measuring device at a spacing from the measuring graduation (9) is adjustable. A material measure of the corresponding test body (1) by means of a spacer (2) in the optimal distance (d With this arrangement, by the inductance of the flat coil (3) is determined certain frequency of an oscillator (5) and stored. In the adjustment of the scanning unit (7) in the measuring device, the support (8) relative to the material measure is moved apart until the frequency of the oscillator (5) matches the stored frequency. | Abstract Taking the paper [1] as a starting point, an algorithm is established whereby all velocities can be directly determined in any plane mechanism with a known degree of mobility regardless of the mechanism structure. A number of applications are given in the last part of this paper to show in a practical way the use of this algorithm. | eng_Latn | 28,906 |
A COMPACT 5MeV S-BANDELECTRON LINACBASEDX-RAYSOURCE FOR INDUSTRIALRADIOGRAPHY. | A compact andreliable X-raysource, based ona5MeV, 1kW,S-band electron linac, hasbeensetupattheDipartimento diFisica, Universit'a diMessina. Thissource, coupled withaGOSscintillator screen andaCCD camera,represents aninnovative transportable system forindustrial radiography andX-raytomography. Optimization of theparameters influencing thee-yconversion andtheXraybeamcharacteristics havebeenstudied bymeansofthe MCNP-4C2(Monte-Carlo-N-Particle, version 4C2)code. Theconverter choice istheresult ofthestudy ofthee-y conversion performances fordifferent materials andmaterial thicknesses. Alsotheconverter position withrespect to thelinac exit windowhasbeenstudied. Thechosen converter consists inaW-Cutarget inserted close tothelinac window. Inthefinal source project, acollimation system provides a14cmdiameter X-rayspotatthesample position, andpreliminary radiographic results havebeenobtained byinspecting different density materials andthicknesses. | Scientific data return with the help of laser communication is a promising way in deep-space exploration.The United States has begun to carry out research work about deep-space laser communication(DSLC).However,our country has not yet had any reports.In this situation,the article takes Mars to earth's DSLC as the research object.According to the analysis of external constraint conditions,design principles of two important systems,which consist of the communication and APT subsystems,is proposed and in-depth design of critical parameters has been carried out.Subsequently,accurate pointing and tracking concept based on celestial body imaging is ideated.Promising scheme of DSLC is put forward for the first time in our country. | yue_Hant | 28,907 |
A structure of angular acceleration sensor using silicon cantilevered beam with piezoresistors | A piezoresistive angular acceleration sensor is developed by micromachining. The proposed angular acceleration sensor consists of four identical silicon cantilevered beams with piezoresistors which are arranged at the circumference of the rotary machine. The value of the piezoresistor changes according to the acceleration. The fabrication method of the silicon cantilevered beams and the electrical characteristics of the piezoresistors are shown. The theoretical relation between the acceleration force and the resistance variation of the piezoresistor is derived in accordance with a geometrical model of the silicon cantilevered beam. The simple dynamical behavior of the piezoresistive cantilevered beam is also discussed. Then, the optimal arrangement of the uniaxial acceleration sensors for measuring the angular acceleration in the rotary machine is considered. Experimental results are shown and discussed. > | Abstract According to the method described in reference [1], we have designed a series of corrector systems for Cassegrain telescopes automatically with an electronic computer. The calculations were carried out under the following two conditions: the primary and secondary mirrors have strictly conical surfaces, and the telescope is strictly free from third-order spherical aberration when the corrector systems are taken off. Results in this papercan be converted proportionally to real telescopes of any aperture, while the aberrations expressed in seconds of arc remain unchanged. | eng_Latn | 28,908 |
Study of system scheme design and countermeasures of line-of-sight pointing in deep-space laser communication | Scientific data return with the help of laser communication is a promising way in deep-space exploration.The United States has begun to carry out research work about deep-space laser communication(DSLC).However,our country has not yet had any reports.In this situation,the article takes Mars to earth's DSLC as the research object.According to the analysis of external constraint conditions,design principles of two important systems,which consist of the communication and APT subsystems,is proposed and in-depth design of critical parameters has been carried out.Subsequently,accurate pointing and tracking concept based on celestial body imaging is ideated.Promising scheme of DSLC is put forward for the first time in our country. | The invention relates to a method and a system for diagnosis of one or more rail vehicles, which each at least comprise at least one measuring device for detecting measured values of a measured variable, comprising the following method steps: - acquiring measurement values by means of at least a measuring device at least one rail vehicle, - transmitting the measured values from the rail vehicle to a route-side control center, - evaluating the measured values in the control center by means of a predetermined algorithm, and - providing a result of the evaluation for output. | eng_Latn | 28,909 |
Metrological analysis of the LIDFT method | The estimation error components in the DFT linear interpolation (LIDFT) method have been presented in the paper. The equations for random errors, total error, the minimum and optimal parameter value of data window for the case of one complex oscillation, and also the metrological analysis of the multifrequency signal case are presented. This analysis allows us to estimate final method accuracy and obtain the relation for the optimal data window parameter. | A Certain Airplane’s Hydraumatic Systems Fault Diagnosis Device was designed, but there were some nonlinear factor within the sensor’s input-output, and the magnify circuits; there were many random errors in the used components. So the obvious relation of the input-output could not be found. A least square method was adopted in nonlinear fitting, so the hardware and software of this Fault Diagnosis Device were simplified. | eng_Latn | 28,910 |
Phases of spin- and mass-imbalanced ultracold Fermi gases in harmonic traps | We analyze the phase structure of mass- and spin-imbalanced unitary Fermi gases in harmonic traps. To this end, we employ density functional theory in the local density approximation. Depending on the values of the control parameters measuring mass and spin imbalance, we observe that three regions exist in the trap, namely, a superfluid region at the center, surrounded by a mixed region of resonantly interacting spin-up and spin-down fermions, and, finally, a fully polarized phase surrounding the previous two regions. We also find regimes in the phase diagram where the existence of a superfluid region at the center of the trap is not energetically favored. We point out the limitations of our approach at the present stage and call for more detailed (ab initio) studies of the equation of state of uniform, mass-imbalanced unitary Fermi gases. | To analyze the relationship between the deceleration-free servo system's tracking error and electrostatic gyroscope monitor's six-time calibration,the reason and the solution method of six-time calibration working abnormally are given.By analyzing the academic relationship among the deceleration-free servo system's tracking error,h angle transformation and azimuth angle,a new six-time calibration method is proposed.In this method,the equatorial gyroscope and polar gyroscope are calibrated at the different time according their azimuth angles.By several dynamic tests,the method is proved effectively with 100% success rate when the deceleration-free servo system's tracking error or the ship rocking is over the mark.By using the method,the electrostatic gyroscope monitor is more applicable in the ships. | eng_Latn | 28,911 |
Vibration stabilization for the final focus magnet of a future linear collider | One of the accelerator projects currently being studied is the construction of a linear collider composed of two 16 km arms face to face. Nominal luminosity is of the order of 1034cm-2s-1. For such a performance, one must take into account the ground nanodisplacements induced by cultural noise. The machine optical elements must be stable and in particular the movements of the two final focus magnets must be smaller than a third of the beam size. This can only be achieved through active stabilization. The current mechatronics study focuses on three subjects. First, one needs adapted sensors and actuators to measure nanodisplacements and achieve the required stabilization. Secondly, mechanical models are being tested to help optimize the final design. In a third part, a feedback loop is being developed to obtain the vibration stabilization of the whole system. | Gyroscope is the main error source in independent navigation system besides initial angle error and accelerometer zero error. In this paper, Inertial Gyrocompass system is designed by deep analysis of INS model. By mean of involving horizontal damping network, azimuth damping network and optimal choose of damping network parameter, inertial Gyrocompass can bring high precision location on the basis of low accuracy float gyros and velocity information of Doppler log. Computer simulation and experimentations show this scheme is effective and practicable. | eng_Latn | 28,912 |
Airport Surface Movement – Critical Analysis of Navigation System Performance Requirements | The CNS/ATM concept envisages reliance on global satellite navigation systems to underpin future air traffic management that is able to cope with the ever-increasing demand for air travel without jeopardising safety and the environment. In order to benefit from GNSS, it is crucial that the navigation performance required of air navigation systems is derived and agreed, based on sound principles. Significant work has been undertaken to date and agreement reached on the navigation requirements for the phases of flight up to Category I (CAT-I) precision approach, and proposals are under discussion for CAT-III precision approach. This paper completes a typical flight profile by addressing airport surface movement, and proposing the requirements based on operational requirements for each airport category, to support operations in zero visibility conditions. The benefits of the approach taken in the derivation of the requirements are discussed relative to the existing navigation requirements. | ABSTRACTThis paper concerns on the bearing-based leader–follower formation manoeuvre control problem for two- (2D) and three-dimensional (3D) multi-agent systems with nonholonomic constraint. The t... | eng_Latn | 28,913 |
Compensation and Analysis on Size Effect Error of Accelerometers of INS Caused by Single-axial Rotation | In order to reduce size effect error of accelerometers caused by single-axial rotation of the single-axial rotation of INS(SRINS),the size effect error of accelerometers caused by the rotation was analyzed,the error of velocity caused by the size effect error of accelerometers was researched,and the compensation method was offered.According to theory analysis and simulation results,the size effect error could not bring on emanation of positioning error,however,it would increase surge of velocity errors,for the damping system,it would bring on bigger velocity errors;The precision was improved in the rotating process by compensating the size effect errors. | In this paper,the stability of a class of stage structure SIS model with small delay is studied.The sufficient conditions for asymptotical stability of the equilibrium are given.Some simulations are carried out by matlab software to support the correctness of our analysis results.Owing to the small delay,the results are the continuation and complement of the previous authors. | eng_Latn | 28,914 |
Stabilizing an Unstable Orbit about L3 in the Sun, Earth, Moon System Using Linear Constant Gain Feedback. | Abstract : Equations of motion for a satellite in a planar, elliptic four-body system are used to generate an orbit about L3. Initial conditions and a periodic reference orbit were found using a circular four-body model. Linear constant gain feedback is used to stabilize the orbit about L3 in the planar, elliptic four-body model. The computed L3 orbit is plotted against the reference orbit to assess the effectiveness of position, velocity and position/velocity feedback compensation systems. Also computed is the integrated control gain costs for each type of feedback system used. Long term stable motion near libration point L3 was achieved using position/velocity feedback compensation. Position and velocity feedback when used separately were ineffective as stabilizing feedback compensation systems. The integrated control gain costs also indicate that linear constant gain feedback is not an economical method to stabilize this periodic orbit about L3. (Author) | When extracting geo-referenced 3D data from cameras mounted on Mobile Mapping Systems, one of important properties for accuracy of extracted data is the alignment of the relative translation(lever-arm) and rotation(bore-sight) between the coordinate systems of Inertial Measurement Unit(IMU)/Ground Positioning System(GPS) and cameras. Since the conventional method calculates absolute camera orientation using ground control points (GCP), the alignment is determined in one Coordinated System (GPS Coordinated System). It basically require GCP. We proposed a mathematical model for the alignment using the initially uncoupled data of cameras and IMU/GPS without GCPs. | eng_Latn | 28,915 |
Research and realization of inertial gyrocompass system Based on INS | Gyroscope is the main error source in independent navigation system besides initial angle error and accelerometer zero error. In this paper, Inertial Gyrocompass system is designed by deep analysis of INS model. By mean of involving horizontal damping network, azimuth damping network and optimal choose of damping network parameter, inertial Gyrocompass can bring high precision location on the basis of low accuracy float gyros and velocity information of Doppler log. Computer simulation and experimentations show this scheme is effective and practicable. | Sooner or later each manufacturer, because of the rising level of competition on the market, will have to find a way to decrease the expenses and to increase the profit. Optimization is the way to make that. In this paper optimization of metal masts construction using ANSYS Mechanical and IOSO algorithms will be discussed. Loads are automatically calculated according to the Code of Rules 20.13330.2011 and load*bearing elements are checked for strength and stability according to the Code of Rules 16.13330.2011. After the optimization run a Pareto set is created which allows to manually choose an optimal variant of construction. | eng_Latn | 28,916 |
Software Development of DGPS Guidance for Agriculture Machinery Straight Line Operation | DGPS navigation has many virtues on agricultural unit which has large or middle scale with wide swath and operates in big area field. Using VB6.0 program language, a application software which could offer programs including GPS information procuring, projection transform, guidance AB line for farm machine straight line operating with DGPS navigation was developed. It could be used in touching screen computer for straight line navigation in the agricultural production. Results of simulation test using field work records indicated this software could realize navigation effectively and could record operating course and display the distance and area of operation simultaneously. | By means of the program based on the pixel coordinate information AutoCAD DLG graphics were extracted, transformation, update, the DLG graphics coordinate was transformed. DLG graphics coordinates transformation would solve the problems that often encountered in daily work gathered DLG data coordinate system is dif erent from the actual requirement of the dii culties, especially for conversion to solve everyday small batch DLG graphics coordinate system, low cost, convenient use. | eng_Latn | 28,917 |
A dismantled and assembled measuring platform for intertidal zone feng chang | The utility model provides a dismantled and assembled measuring platform for intertidal zone feng chang, include: the intertidal zone is squeezed into as the ground to the bottom support, the main support, through can dismantle the mounting with the bottom leg joint, the main support is multi -segment type structure, adopts between each section can dismantle the mounting connects, platform, detachable are installed in the main support top, wind meter is fixed in on the platform. By last, the intertidal zone is squeezed into to the measuring platform ground, and the frame is firm. Adopt multi -segment type structure, can adjust the height of main support according to the demand, make the whole height of measuring platform can reach 10 meters, set up wind meter at the measuring platform top, realize measuring to the amount of wind of intertidal zone position. Dismantled and assembled platform, the simple installation is swift, is applicable to short characteristics of intertidal zone ebb activity duration. | Abstract Reducing the specimen-probe spacing to increase the sensitivity of measurement of weak remanence in geological samples, etc. introduces potential inaccuracies. These are analysed by comparing the field distributions derived for transversely magnetized cylinders with those for dipoles and for nulling coils. An optimum coil geometry is found. | eng_Latn | 28,918 |
Using repeated measures to correct correlated measurement errors through orthogonal decomposition | AbstractIn a physical activity study, the 7-day physical activity log viewed as an alloyed gold standard was used to correct the measurement error in the physical activity questionnaire. Due to correlations between the errors in the two measurements, the usual regression calibration may result to a biased estimate of the calibration factor. We propose a method of removing the correlation through orthogonal decomposition of the errors, then the usual regression calibration can be applied. Simulation studies show that our method can effectively correct the bias. | Abstract We have developed image analysis software to facilitate the analysis of optical-transition radiation (OTR) patterns generated by the electron beam from the Los Alamos free-electron laser facility. The software can be used for beam alignment, beam profile and angular divergence measurements, and the programs run on an IBM AT microcomputer. The programs and their use are described and some results shown. | eng_Latn | 28,919 |
Method and arrangement for the optical detection of an illuminated sample | Method and apparatus for depth-resolved optical detection of a sample in which a sample or a part thereof is scanned by means of preferably line-shaped lighting, the illumination of the sample in focus is patterned periodically in at least one direction in space, be detected coming from the sample light and produces images of the sample and from the images of at least one optical section image and / or an image with increased resolution is calculated by the sample, an image pickup section and image offsetting is performed several times while changing the orientation of the line-shaped illumination to the sample and / or Gaps are on an area detector or a camera for linewise unscanned detection between exposed with detection light from the illuminated sample area of lines generated and / or a further deflection of light in the direction of scanning of the sample is carried by line during a scanning operation prior to the detector. | Intelligent instrument has been widely used in various fields of life and production.When it was used with monitoring technology,the problem of measuring dangerous area can be solved efficiently.In this paper,character tilt and location were brought into focus.To solve tilt problem,rotation correction method was proposed based on the theory of perspective projection transformation.To solve location problem,sliding window method was proposed by using gray comparison.Experimental results show that these two methods can solve character tilt and location problem in character recognition of intelligent instrument. | eng_Latn | 28,920 |
Three-dimensional input device and input system | PROBLEM TO BE SOLVED: To provide a three-dimensional input device and input system that are operable with no limit to a service space and a use state.SOLUTION: A three-dimensional input device comprising: two optical measurement means 12a and 12b disposed at a predetermined interval; a three-dimensional position detector 1 that measures the three-dimensional position of a measuring object based on the direction and the predetermined interval of the measuring object separately obtained by the two optical measurement means on a real-time basis and is mountable to a human body; and a controller 13, characterized in that the controller generates input information based on variation in the three-dimensional position and how the measuring object is varied.SELECTED DRAWING: Figure 1 | Abstract In this paper finite element analysis of the large deflection behaviour of skew plates has been done. A high precision conforming triangular plate bending element has been used. The central deflection, bending and membrane stresses have been reported for simply supported and clamped rhombic plates. The variations of these quantities have been studied for different skew angles. | eng_Latn | 28,921 |
Software implementation of star calibration for instrumentation radar | The bias of the radar measured coordinate value of a star compared to the theoretical coordinate value, accurately calculated from astronomical knowledge, can be used to find out those mechanical factors affecting the accuracy of the radar measurement in azimuth and elevation. Thus the raw target coordinate values obtained from a radar system could be calibrated. A high accuracy of estimated error coefficients can be obtained by using least squares methods and calculating the apparent position coordinates in a rectangular coordinate system. Both the theory and software implementation of star calibration for instrumentation radar are described in this paper. | Over the course of the last two decades, continuous advances in the stereo vision field have been documented. In this paper we present an analysis of the efficiency for the stereo vision algorithm of the Census Transform algorithm. In addition to the conventional correlation method based on Hamming distance minimization, we use two similarity measures: the Tanimoto and the Dixon-Koehler distances. Then, we compare its performance in terms of accuracy and hardware resources needed for implementation. These comparisons are performed by introducing a generalized model for each hardware architecture, scalable depending on design parameters such as Census Transform window size and maximum disparity range. | eng_Latn | 28,922 |
Application of Excel for Dealing with Wire Measuring Data with hanging compass | The paper has introduced the ways and steps of application Excel for dealing with wire measuring.It also tells us how to use excel to solve the problems such as lofting,calculating and checking. | Kinematics analysis and Kinematics errors considering structural erro rs calculating formula are deduced.The calculating software i s developed by means of Visual Basic 6.0.senior language The Kinematics analysis of plane linkage mechanism considering structural errors are r ealized by using this software. | eng_Latn | 28,923 |
Automated design of Switched Current Sigma-Delta Modulator with a new comparator structure | The paper presents a VHDL-AMS based approach to the Switched-Current (SI) Sigma-Delta Modulator design. EDA tools are presented, which translate the prototype VHDL-AMS description into SI realization. Another tool helps the designer to create the layout. The paper also describes a new proposed current mode comparator, which is used in the design. Postlayout simulation results are presented. | According to the characteristics of the high precise GPS deformation monitoring, basing on the first period observation results of the monitoring network,the similar single-difference model of solving GPS monitor point deformation information at single epoch is built,and the receivers'antenna phase center offsets are discussed.This model avoids the troublesome problem of cycle slip detecting and repairing,and is not only applicable to the static and dynamic monitoring modes, but also suitable for the single receivers.The correctness of the similar single-difference model is verified with the practical data in Three Gorge Area. | eng_Latn | 28,924 |
Identification and Fault Diagnosis of an Industrial Gas Turbine Using State-Space Methods | The objective of this paper is to identify, detect and isolate faults to an industrial gas turbine. The detection scheme is based on the generation of so-called "residuals" that are errors between estimated and measured variables of the process. A State-Space model is used for identification and some observer-based methods are used for residual generation, while for residual evaluation a neural network classifier for MLP is used. The proposed fault detection and isolation tool has been tested on a single-shaft industrial gas turbine simulator. | This paper deals with the transfer alignment problem of strapdown inertial navigation systems, using the velocity information and angular rate information of the ship. Major error sources for velocity-plus-angular rate matching is unmodeled ship body flexure dynamics. To reduce this alignment error, a two-stage strong tracking filter (TSTF) is designed. This TSTF is derived by merging the optimal two-stage Kalman filter with strong tracking filter. The ship body flexure is modeled as time-varying noise and its stochastic properties are estimated by TSTF. The simulation results show that the proposed method is effective to estimate the misalignment angles of the slave inertial navigation systems. | eng_Latn | 28,925 |
Use of Venus gravitational field for solar probe trajectory control | Friedman, H., "NAS-SSB Calls for Cluster-Satellite Deployments/' Astronautics & Aeronautics, Vol. 7, No. 1, Jan. 1969, p. 23. 2 French, F. W., Rodman, A. K., and Huguenin, G. R., "A Synthetic Aperture Approach to Space-Based Radio Telescopes," Journal of Spacecraft and Rockets, Vol. 4, No. 12, Dec. 1967, pp. 1649-1656. 3 Hrastar, J. A., "Dynamic Control Study for Two Closely CoOrbiting Satellites," X-732-70-169, 1970, NASA. 4 Bainum, P. M., Stuiver, W., and Harkness, R. E., "Stability and Deployment Analysis of a Tethered Orbiting Interferometer Satellite System," paper presented at the Eighth European Space Symposium, Venice, Italy, May 1968, Applied Physics Lab., John Hopkins Univ. 6 Liebelt, P. B., An Introduction to Optimal Estimation, Addison-Wesley, Reading, Mass., 1967, Chap. 6. | The paper presents an analysis of the tracking loop, its dynamic and sampling requirements when it is designed to be an ::: essential part of the deeply coupled GNSS receiver. All the tracking loops of the GNSS receiver significantly influence ::: final GNSS receiver performance. Robustness of the tracking process can be improved using deeply coupled ::: architecture, when tracking loops inside of the GNSS receiver are supported with accelerations and velocities measured ::: in INS. | eng_Latn | 28,926 |
Interaction parameter calculations from contact angle data | Abstract Application of the Girifalco-Good-Young equation to measurements of liquid/solid contact angles on various substrates, leads to the surprising conclusion that the interaction parameter Φ is near unity for most liquids. The exceptions appear to be small polar molecules, e.g., water, glycerol, and methylene iodide. The implications of this finding are examined. | Three methods for obtaining a two body fix are presented. For practical use a calculator with magnetic card capacity is necessary. Advantages of the methods are: One simple rule covering all positions is sufficient to avoid ambiguity, the methods can be used in all positions, an approximate position is not necessary, and the fix is calculated directly. One method employs rotation of a spherical triangle and two methods are based on vector calculation. | eng_Latn | 28,927 |
Linear and angular velocity and displacement sensors for industrial use based on planar optical technology | An overview will be given for a series of compact optical systems for measurement of surface displacement. These systems are particularly well suited for miniaturization due to the limited demand for spatial and temporal coherence of the source. Specifically, systems for linear and angular displacement will be described. The systems have been realized based on the use of holographic optical elements but implementations with various kinds of compact diffractive optical elements will be devised. Common features with most of the proposed systems are the use of common-path interferometry and the simultaneous recording of the transmitter and receiver optics, strongly reducing any demand for alignment after assembly. Further, the use of common path systems will reduce the sensitivity to optical turbulence and may reduce the influence of contamination of the optical window.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only. | On the basis of the analysis of typical orthogonal crankrocking lever spatial mechanism for the weft insertion in rapier looms, the rules of the outputting lever motion and the mechanism pressure-angle variety are studied when the maximum swing angle of rocking lever and the length of outputting lever have different values, and the optimum parameters suitable for motion transmission can be chosen. At the same time some existing shortpoints of the mechanism are also pointed out. | eng_Latn | 28,928 |
Device and method for adjusting the drilling direction of a drilling tool for an ophthalmic lens | The device comprises pivoting means enabling the drilling axis (A6) of the drilling tool (35) to be pivoted (PIV) about the axis of orientation, and means for adjusting the angular position of the drilling tool (35) about said axis of orientation. It also comprises first mobility means enabling relative mobility of the drilling tool (35) in relation to the lens to be drilled (L), or vice-versa, according to a first degree of mobility (ESC) which is distinct from the pivoting (PIV) of the drilling axis (A6) of the drilling tool (35) about the axis of orientation, and in that said means for adjustment are configured in such a way as to control the pivoting (PIV) of the drilling axis (A6) of the drilling tool (35) about the axis of orientation, in favour of the first degree of relative mobility of the drilling tool (35) in relation to the lens (L) that is to be drilled. | In this paper we introduce an algorithm for omnidirectional virtual view synthesis based on Omnidirectional Video plus Depth (OVD) format. The implementation is done on the basis of View Synthesis Reference Software (VSRS) developed by MPEG of ISO/IEC. Also, we address the problem of lack of benchmark data disallowing objective quality assessment. We present a method for generating test images in OVD representation along with example omnidirectional images and omnidirectional depths, called “Poznan Hall 360 ”. | eng_Latn | 28,929 |
A detailed 3D ankle-foot model for simulate dynamics of lower limb orthosis | The objective of this study is to develop a 3D ankle-foot model containing toe expression for designing an AFO (ankle-foot orthosis) with a training function. Two experiments were conducted to (1) show the influence of toes by comparing walking with and without an AFO, and (2) clarify the functions of toes during walking by correlating the activity of the major muscles controlling the ankle and the toes to the sole pressure data during walking. By analyzing the results of these two experiments, the necessary components and conditions of a detailed 3D foot-ankle model for developing an AFO with a training effect were clarified. A model was built and examined with empirical facts, and data were collected from the AFO simulation. | Mobile location estimation has attracted much interest over the past few years. The most challenging issues, which render to reach the required accuracy for the time-based location system, are multipath and non line-of-sight (NLOS) problems. This paper suggests the simple but robust techniques using biased Kalman filter to smooth and mitigate the NLOS effect for TOA measurements. The processed TOAs are then used for DTOA formulation and provided for location estimation. The further tracking stage is shown not to improve the accuracy much but to be necessary to smooth the mobile trajectory. The better accuracy for mobile location is suggested for future work by using the geographical information through searching the match between the path loss measured at multiple BSs and that estimated by ray-tracing techniques. | eng_Latn | 28,930 |
Power Transformer Fault Diagnosis Model Based on Rough Set Theory with Fuzzy Representation | Objective Due to the incompleteness and complexity of fault diagnosis for power transformers, a comprehensive rough-fuzzy scheme for solving fault diagnosis problems is presented. Fuzzy set theory is used both for representation of incipient faults' indications and producing a fuzzy granulation of the feature space. Rough set theory is used to obtain dependency rules that model indicative regions in the granulated feature space. The fuzzy membership functions corresponding to the indicative regions, modelled by rules, are stored as cases. Results Diagnostic conclusions are made using a similarity measure based on these membership functions. Each case involves only a reduced number of relevant features making this scheme suitable for fault diagnosis. Conclusion Superiority of this method in terms of classification accuracy and case generation is demonstrated. | This paper deals with the transfer alignment problem of strapdown inertial navigation systems, using the velocity information and angular rate information of the ship. Major error sources for velocity-plus-angular rate matching is unmodeled ship body flexure dynamics. To reduce this alignment error, a two-stage strong tracking filter (TSTF) is designed. This TSTF is derived by merging the optimal two-stage Kalman filter with strong tracking filter. The ship body flexure is modeled as time-varying noise and its stochastic properties are estimated by TSTF. The simulation results show that the proposed method is effective to estimate the misalignment angles of the slave inertial navigation systems. | eng_Latn | 28,931 |
Calibration Of Surface Heights In An Interferometric Optical Profiler | The numerical aperture (NA) of a microscope objective can affect the measurement of surface height profiles. Large NA objectives measure height values smaller than the actual values. An experiment to calibrate these effects on objectives with NAs of 0.1 to 0.95 is described using four traceable step height standards and a computer-controlled interferometric optical profiler utilizing phase-measurement interferometry techniques. The measured NA scaling factors have good agreement with a theory developed by Ingelstam and indicate that the effective NA rather than the nominal NA is the important quantity. NA scaling factors are determined to an uncertainty of ±1% for NAs of 0.5 or less and ±2% for NAs of 0.9 or greater. | Intelligent instrument has been widely used in various fields of life and production.When it was used with monitoring technology,the problem of measuring dangerous area can be solved efficiently.In this paper,character tilt and location were brought into focus.To solve tilt problem,rotation correction method was proposed based on the theory of perspective projection transformation.To solve location problem,sliding window method was proposed by using gray comparison.Experimental results show that these two methods can solve character tilt and location problem in character recognition of intelligent instrument. | eng_Latn | 28,932 |
IMPEDANCE MAPPING EXTRAPOLATION | A mapping approach to impedance extrapolation is presented in this paper. With the assumption of small reflection coefficients, it is derived that there exists an approximately linear mapping relationship between logarithmic impedances and seismic traces. Such a mapping can be realized by applying adaptive filtering. The test result of field data is given. It is shown that the derived impedance or interval velocity profiles bear higher resolution and better well logs correlation than those derived from the conventional method. It turns out to be a kind of supplementary means to inversion technique in production seismology. At last the limitation of the mapping approach is discussed. | In this paper, we have presented an effective yield improvement methodology that can help both manufacturing ::: foundries, fabless and fab-lite companies to identify systematic failures. It uses the physical addresses of failing bits ::: from wafer sort results to overlay to inline wafer defect inspection locations. The inline defect patterns or the design ::: patterns where overlay results showed matches were extracted and grouped by feature similarity or cell names. The potentially problematic design patterns can be obtained and used for design debug and process improvement. | yue_Hant | 28,933 |
Digital measurements of propagation loss in optical organic polymer waveguides | Many conventional methods to detect propagation losses in optical waveguides, such as Cut-Back Method and Prism-Sliding Method, are either destructive or inconvenient. Here we demonstrated a new method -- CCD camera photographing method. A CCD camera was used to take digital photographs of the light streak in the waveguides and the scattered-light intensity distribution is recorded. After fitting the intensity distribution into an exponential attenuate curve, the propagation loss finally can be calculated from the attenuation coefficient of the curve. Compared with other detecting methods, it is more convenient and accurate. In our experiment, samples of polymer waveguides with propagation losses less than 0.5 dB/cm were fabricated. | This paper presents three mathematical models for the correction of measurement errors of a prototype system designed for Large Scale Dimensional Metrology (LSDM) applications. The system, developed in the Quality and Industrial Metrology Laboratory of Politecnico di Torino, is based on the principles of photogrammetry and consist of a set of cameras wirelessly connected to a central unit for data elaboration and able to track the position of a hand-held contact probe. Due to its architecture the system is affected by several systematic error sources. This paper addresses some of them: the distortion of the lenses, the dimension of the probe tip and the kinematic of the probe. By means of the implementation of appropriate mathematical correction models, the overall system performance is significantly improved as shown by the proposed tests | eng_Latn | 28,934 |
Adie syndrome: evidence for refractive error and accomodative asymmetry as the cause of amblyopia. | PURPOSE ::: To report objective changes in accommodation in a child with Adie syndrome. ::: ::: ::: METHODS ::: A child aged 2 years 10 months when initially examined was found to have good visual acuity in both eyes, a low degree of hypermetropia (isometropic), and Adie pupil presumed to be caused by chicken pox that had occurred 2 months earlier. Amblyopia developed but responded well to treatment, which involved correction of the refractive error and occlusion therapy. Objective changes in the refraction of the eye were measured on the Canon R1 autorefractor at 3.8 m and 33 cm. ::: ::: ::: RESULT ::: The degree of accommodation in the affected eye when both eyes were open was markedly reduced. ::: ::: ::: CONCLUSION ::: The presence of isometropic hypermetropia, which remains uncorrected when Adie syndrome is present, can lead to the development of amblyopia in a child. | Abstract According to the method described in reference [1], we have designed a series of corrector systems for Cassegrain telescopes automatically with an electronic computer. The calculations were carried out under the following two conditions: the primary and secondary mirrors have strictly conical surfaces, and the telescope is strictly free from third-order spherical aberration when the corrector systems are taken off. Results in this papercan be converted proportionally to real telescopes of any aperture, while the aberrations expressed in seconds of arc remain unchanged. | eng_Latn | 28,935 |
Quaternion normalization in spacecraft attitude determination | Methods are presented to normalize the attitude quaternion in two extended Kalman filters (EKF), namely, the multiplicative EKF (MEKF) and the additive EKF (AEKF). It is concluded that all the normalization methods work well and yield comparable results. In the AEKF, normalization is not essential, since the data chosen for the test do not have a rapidly varying attitude. In the MEKF, normalization is necessary to avoid divergence of the attitude estimate. All of the methods of the methods behave similarly when the spacecraft experiences low angular rates. | Quantum Mechanics at Planck scale is considered as a deformation of the conventional Quantum Mechanics. Similar to the earlier works of the author, the main object of deformation is the density matrix. On this basis a notion of the entropy density is introduced that is a matrix value used for a detail study of the Information Problem at the Universe, and in particular, for the Information Paradox Problem. | eng_Latn | 28,936 |
Measurement of Stellar (n, {gamma}) Rates with the Karlsruhe 4{pi} BaF{sub 2} Detector | Measurements of astrophysically relevant (n, {gamma}) rates have been significantly improved in the past decade. An appealing complement to the traditional techniques was the development and implementation of a 4{pi} BaF{sub 2} detector with nearly 100% efficiency. This detector proved particularly successful in meeting long-standing challenges in neutron capture nucleosynthesis. Its potentials will be illustrated by the recent measurement on {sup 180}Ta, a case that was hitherto inaccessible because of the very limited purity and mass of the available sample. | A new multi-sensor optimal information fusion criterion weighted by scalars is presented in the linear minimum variance sense. The criterion considers the correlation among local estimate errors, and only computing the weighted scalar coefficients is needed. Therefore the computational burden can obviously be reduced, and it is convenient to apply in real time. Using steady-state Kalman filtering theory, a multi-sensor optimal information fusion steady-state Kalman filter is given based on this fusion criterion. The information fusion steady-state filter can be obtained only by one time fusing after all local filters enter steady states. Simulation example shows the effectiveness of the proposed method. | eng_Latn | 28,937 |
Experimental Analysis of 25 m Span Straight Guideway Girder | Through an analysis of the 25 m span straight guideway girder experiments,including the static state experiment,fatigue experiment and destruction experiment,this paper concludes that the 25 m span straight guideway girder is much safer for the project, and can provide a basis for the design of guideway girder in proctical engineering. | According to the characteristics of the high precise GPS deformation monitoring, basing on the first period observation results of the monitoring network,the similar single-difference model of solving GPS monitor point deformation information at single epoch is built,and the receivers'antenna phase center offsets are discussed.This model avoids the troublesome problem of cycle slip detecting and repairing,and is not only applicable to the static and dynamic monitoring modes, but also suitable for the single receivers.The correctness of the similar single-difference model is verified with the practical data in Three Gorge Area. | kor_Hang | 28,938 |
A Unified Algorithm for Channel Imbalance and Antenna Phase Center Position Calibration of a Single-Pass Multi-Baseline TomoSAR System | The multi-baseline synthetic aperture radar (SAR) tomography (TomoSAR) system is employed in such applications as disaster remote sensing, urban 3-D reconstruction, and forest carbon storage estimation. This is because of its 3-D imaging capability in a single-pass platform. However, a high 3-D resolution of TomoSAR is based on the premise that the channel imbalance and antenna phase center (APC) position are precisely known. If this is not the case, the 3-D resolution performance will be seriously degraded. In this paper, a unified algorithm for channel imbalance and APC position calibration of a single-pass multi-baseline TomoSAR system is proposed. Based on the maximum likelihood method, as well as the least squares and the damped Newton method, we can calibrate the channel imbalance and APC position. The algorithm is suitable for near-field conditions, and no phase unwrapping operation is required. The effectiveness of the proposed algorithm has been verified by simulation and experimental results. | A new modeling method based on sample data is described in this paper,through physics and sample date analysis on displacement vs.voltage characteristics of x-y plane of cylindrical piezoelectric scanner used in scanning probe microscope(SPM).Through sample data statistical analysis,and considering the error factors such as scan speed,scan angle,nonlinearity and coupling,a model represented by a binomial plus some error expressions is constructed.A nonlinearity correction expression based on the model is deduced.With the software Matlab this nonlinearity correction is simulated.The result of simulation indicates that it can eliminate the errors effectively.The ascendency of the method is that there are no polarization mechanism analysis and fewer number of model parameters.The method is practical applied to engineering. | eng_Latn | 28,939 |
Discussion of "Assessment of voltage unbalance" [and closure] | The original paper "Assessment of voltage unbalance" (A. von Jouanne, see ibid., vol.16, p.782-90, 2001) is discussed by the authors in this paper. The original author's response to the paper discussions are also included as closure. | Abstract Vertical arrays of temperature and conductivity sensors are towed from research vessels to obtain cross sections of the ocean's internal structure that result from the dynamic finescale and microscale processes. To estimate local water displacements and other quantities of interest from these sensors, it is required that they be accurately calibrated. However, drifts in sensor electronics and sensor aging result in offsets from these calibrations. These offsets generally cannot be accounted for during laboratory calibration, so techniques must be used either at sea or later to intercalibrate the array of sensors. In this paper, a method is presented for intercalibrating the sensors by cycling the array in depth while the array is towed horizontally to determine the relative offsets and gains between the sensors. This method eliminates the ambiguity of other methods which require some assumed shape of the vertical temperature or conductivity profile and which are especially problematic in arrays h... | eng_Latn | 28,940 |
Results of Fiber-Optic Gyro Testing | The paper presents the information on specific design, accuracy characteristics, and results of testing of a prototype fiber-optic gyro of accuracy grade 0.01°/h, with sensing element spool diameter of 150 mm, designed by Concern RCSI Elektropribor, JSC. The device is compared to a number of sensors of similar accuracy grade, designed by various Russian and international companies. | Interferometry provides the only practicable way to image satellites in Geosynchronous Earth Orbit (GEO) with sub-meter resolution. The Magdalena Ridge Observatory Interferometer (MROI) is being funded by the US Air Force Research Laboratory to deploy the central three unit telescopes in order to demonstrate the sensitivity and baseline-bootstrapping capability needed to observe GEO targets. In parallel, we are investigating the resolution and imaging fidelity that is achievable with larger numbers of telescopes. We present imaging simulations with 7- and 10- telescope deployments of the MROI, and characterize the impact of realistic spectral variations compared with a “gray” satellite. | eng_Latn | 28,941 |
TanDEM-X acquisition status and calibration of the interferometric system | TanDEM-X is a spaceborne SAR mission with the goal to derive a global Digital Elevation Model (DEM) with unprecedented accuracy. This paper describes the way how the global DEM is acquired, explains the changes that have been applied during the first almost 1.5 years in orbit and shows the actual status of the global acquisitions. In the second part, the calibration of the bi-static interferometer is explained. The implications to correct the different effects coming from the baseline, the internal delays in the instrument and the phase measurements themselves enabling the derivation of the height are described and the actual results are presented. | This article through 2604 working face floor to probe bottom water of mine transient in Wangcun Coal Mine,analysed the advantages of transient electromagnetic methodof theoretically,and etting observation point through 2604 face,using Terra TEM transient electromagnetic instrument for observation,through on-site practice to explain this reasonable and accuracy method.Therefore,by transient electromagnetic method in the prediction of bottom water has good application value. | eng_Latn | 28,942 |
Test System for Airborne ILS Navigation Apparatus Based on Artificial Intelligence and Virtual Instrument | ILS (Instrument landing system) is one kind of the important airborne navigation systems. The performances of the airborne ILS navigation apparatus are vital to safeguard the safe landing of the aircraft. This paper reviews the basic work process of the ILS, summarizes the test theory from the artificial intelligence and virtual instrument view point, discussed the test system construction, and presents the detail design thought. Particular attention is paid to the failures isolating problems. It is shown that test system for airborne ILS navigation apparatus based on artificial intelligence and virtual instrument improved the accuracy and reliability. | 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 | 28,943 |
Sliding mode control of a permanent magnet synchronous generator for variable speed wind energy conversion systems | Difficulties in achieving the maximum level of efficiency in power extraction from available wind resources warrant the collective attention of modern control and power systems engineers. A strong movement towards sustainable energy resources, and advances in control system methodologies, make previously unattainable levels of efficiency possible. One such promising method is sliding mode control. This control method, touted for its robustness given un-modeled dynamics present in the system, provides ideal characteristics for application in the control of permanent magnet synchronous generators employed in variable speed wind energy conversion systems. Application of this method for control using dynamic models of the d-axis and q-axis currents, as well as those of the high speed shaft rotational speed show a high level of efficiency in power extraction from a varying wind resource. | Abstract This paper describes the design and principle behind the demonstrated novel lamellar grating out-of-plane gyroscope design. The sensing mechanism is based on out-of-plane motion of movable light-reflecting beams changing the phase relationship between the light reflected off the two sets of beams. This phase relationship is manifested as an intensity change in the zeroth-order diffracted light. The device consists of two in-plane 180° out-of-phase vibrating masses with a set of overlapping light-reflecting beams behaving essentially as a lamellar grating. The commercial SOI-MUMPS process was used to fabricate a prototype. The gyroscope demonstrated a sensitivity of 17.8 μV/(°/s) and linearity error of less than 0.6%. Design issues were addressed and show promise to be overcome. Post-fabrication tuning and better optics design can improve the performance greatly with respect to the current prototype setup. | eng_Latn | 28,944 |
Simultaneous calibration of odometry and camera extrinsic for a differential driven mobile robot | In this paper, a new method on simultaneous calibration of odometry and camera extrinsic for a two-wheel differential driven mobile robot equipped with a fixed pinhole camera, is proposed. By observing several vision landmarks in the environment and recording the measurements from both encoders and camera during an arbitrary robot motion, the calibration could be automatically done. Neither a special trajectory need to be followed, nor other devices are used during the calibration process. Compared with other current solutions, non-holonomic constraint of the mobile robot kinematics is utilized to estimate the wheel axle and simplify the calibration problem. Experiment is conducted to validate the method. | In this note we describe a recent result [I.C. Kim, Homogenization of a model problem on contact angle dynamics, Comm. Partial Diff. Eqns. 33(7–9), (2008), pp. 1235–1271; I.C. Kim, Error estimates on homogenization of free boundary velocities in periodic media, Ann. Inst. H. Poincar, Anal. Non-Lineaire 26(3) (2009), pp. 99–1019] on homogenization and error estimates of a free boundary problem, which describes quasi-static contact angle dynamics on inhomogeneous surface. The method presented here also applies to more general class of free boundary problems with oscillating boundary velocities. | eng_Latn | 28,945 |
Kinematics Analysis and Modeling of 6-R Vertical Joint Manipulator SC-8A | According to the structure characteristic of the SC-8A manipulator,link frames were established based on"the Denavit-Hartenberg Notation"after reviewing the traditional methods of robotics modeling.Therefore,D-H parameters were obtained and a robot kinematics model was built.The analytic solutions of forward-kinematics and inverse-kinematics were reasoned,and the proper joint angles were picked out among the multiple solutions of the inverse-kinematics.The result was simulated using MATLAB and the conclusions were correct. | Abstract : The operational conditions of two spacecrafts performing a rendez-vous in geostationary orbit are given with the relative motion equation and the relevant control law. The concept of position, velocity and attitude measurement of the chaser vehicle with respect to the target one is given in order to allow the evaluation of the measurement errors. Simulations show the effect of the errors sources on the flight path of the approaching vehicle and point out the necessity of a good matching between the sensor accuracy and the minimum impulse level of the actuation system. (Author) | eng_Latn | 28,946 |
Study of position finding for marine navigation based on high-frequency ground-wave | A design method of marine navigation and positioning based on high-frequency ground-wave propagation is presented. It receives the signals transmitted from three land-based transmitters with the time-base-synchronized frequency-modulated continuous waveform and extracts the current distances to the three transmitters and moving velocity of ship by special spectral analysis. With range resolution the method can effectively separate the useful ground-wave signal from the much stronger sky-wave signals. Digital simulation shows that the positioning accuracy is dependent on the signal-to-noise ratio for measurement, and the longer the coherent accumulation time is, the higher the positioning accuracy is. | In a stereo configuration, the measurable disparity values are integral, therefore the measurable depths are discrete. This can create a trap for a safety system whose purpose is to estimate the trajectory of a moving object, and issue an early warning. Accuracy of this estimation is determined by the samples which have different measurable depths. Change in measurable depths becomes obvious for closer regions, but due to the limited extent of the stereo common field of view for these regions, the object might not be in the common field of view. A velocity estimation algorithm has been created, which takes into account the constraints of stereo, while accurately estimating the object's trajectory. From examination of various scenarios, we show that a stereo system could be misleading while estimating the object trajectory: it could predict that an object on a collision course is ‘safe’. | eng_Latn | 28,947 |
Two-stage strong tracking filter with its application in transfer alignment | This paper deals with the transfer alignment problem of strapdown inertial navigation systems, using the velocity information and angular rate information of the ship. Major error sources for velocity-plus-angular rate matching is unmodeled ship body flexure dynamics. To reduce this alignment error, a two-stage strong tracking filter (TSTF) is designed. This TSTF is derived by merging the optimal two-stage Kalman filter with strong tracking filter. The ship body flexure is modeled as time-varying noise and its stochastic properties are estimated by TSTF. The simulation results show that the proposed method is effective to estimate the misalignment angles of the slave inertial navigation systems. | In an optical multilayer thin film system, interference effects play an important role for the outcoupling of light due to the different refractive indices and thicknesses of the involved layers. A theoretical model has been investigated with the ability to calculate the outcoupled intensity of light for various wavelengths and viewing angles. ZnS:TbF3 ac-TFEL devices have been prepared to verify the model and to check the applicability of the theory to electroluminescent devices. Experimental and calculated wavelength and viewing angle dependent intensity data show good agreement. The outcoupling efficiency ηopt of a TFEL device can be increased up to 25% compared with the value given by the well known formula of the simple theory /1/. | eng_Latn | 28,948 |
Visualization of fluctuating surface pressure distribution on bluff body using electronically scanned pressure ESP sensors. (Part-2). | Measurements have been made on simultaneous fluctuating surface pressure distribution of 3-dimensional bluff bodies. We carried out wind tunnel experiments using various models with different aspect ratio(1:1:1, 1:1:3, 1:1:5 ; cubic cross section). Measuring system has 512 point pressure transducers(16 channel per 1 module which has electrically scanned multiplexer and preamplifier) and 32 channel analog to digital converters. Observation has been made on 16mm movies created by mean of computer graphics. It was found that various pressure distribution patern can be observed using this new system. | An air sampling system developed to evaluate air quality in biosphere reserves or in other remote areas is described. The equipment consists of a Dupont P-4000A pump and a specially designed battery pack containing Gates batteries. This air sampling system was tested in southern Utah and at 10 remote sampling sites in the Great Smoky Mountains National Park. The equipment was backpacked to the remote sampling sites, and was operated continuously at full capacity for a maximum 8-day period. Except for tampering by curious hikers at one site, the equipment operated satisfactorily. | eng_Latn | 28,949 |
Sinusoidal wavelength-scanning interferometers for shape measurements | Sinusoidal wavelength-scanning (SWS) interferometry is unique in that a time-varying interference signal contains phase-modulation amplitude Zb due to the SWS besides a conventional phase a. A rough value of an optical path difference (OPD) longer than a wavelength is obtained from the amplitude Zb, which is useful for ::: shape measurements of rough surfaces. By combing the two values of Zb and a, an OPD longer than a wavelength can be measured with a high accuracy of the order of nanometer, which is useful for shape ::: measurements of optical surfaces. As light sources of SWS interferometers a tunable laser diode with an external cavity is used and a superluminescent diode (SLD) is used with an acousto-optic tunable filter. A shape of a metal surface, a step shape of an optical surface, and a thin-film shape of optical surfaces are measured. | This paper proposes a level set based coastline detection method by using the template initialization and local energy minimization. It can complete the sea-land boundary detection in infrared channel image. This method is an improvement on the traditional level set algorithm by using the information of GSHHS to optimize the initialization procedure, which can reduce the number of iterations and numerical errors. Moreover, this method optimizes regional energy functional, and can achieve the rapid coastline detection. Experiments on the IR image of FY-2 satellite show that the method has fast speed and high accuracy. | eng_Latn | 28,950 |
In-Orbit Verification for Accelerometers Using Rotating Spacecraft Method | A feasibility analysis of in-orbit performance verification of a high accuracy accelerometer by rotating spacecraft shows that resolution,center of mass offset,scale factor and misalignment of the accelerometer could be measured,and the expected measurement accuracy using this method based on the parameters of the GRACE mission is also presented.It is not only helpful to verify in-orbit performance of the accelerometer,but also significant for the data processing of gravity field determination from satellite. | In this paper the authors investigated the effects of web arrangements on vibration of welded structure gears. The circumferential, radial and axial vibration accelerations of various types of welded gears were measured under different running conditions. The vibration accelerations of welded gears increase generally with an increase in the rigidity of web and rim parts of the gears. A double web gear shows the largest values of vibration accelerations and an asymmetric type of a welded gear the smallest ones due to the effects of the axial force, which is produced by a deformation of the rim and the web parts of the welded gear. The conversion rate of the circumferential vibration into a radial or axial one is different according to the type of the web arrangement. | eng_Latn | 28,951 |
Mechanical Design on Finite Element Method for Ring Laser Gyroscope | The gyroscopes have been used as a suitable inertial instrument for the navigation guidance and attitude controls. The accuracy as very sensitive sensor is limited by the lock-in region (dead band) due to the frequency coupling between two counter-propagating waves at low rotation rates. This frequency coupling gives no phase difference, and an angular increment is not detected. This problem can be overcome by mechanically dithering the gyroscope. This paper presents the design method of mechanical dither by the theoretical considerations and the verification of the theoretical equations through FEM applications. As a result, comparing to the past result, the maximum prediction error of resonant frequency was within 3 percent and peak dither rate was within 5 percent. It was found that the theoretical equations can be feasible for the mechanical performance of dither. | The authors explore how the use of molecular dynamics simulations with relatively small systems can be viewed as a complementary tool to provide key input (bridge functions) for an accurate integral-equation formalism. The results do indeed show that an efficient description of the microscopic structure of liquid metals can thus be attained by means of inexpensive MD runs with a small number of sample particles. | eng_Latn | 28,952 |
3DoF Multi-Rotor Experimental Testbed for Teaching Control Systems | To meet the academic objectives for courses related with Control Systems, it is important to have access to real educational platforms that help to extend the theory to a hands-on experience. This paper introduces the implementation of an experimental testbed used to control the orientation of a multirotor in an interactive fashion. The testbed is implemented based on the configuration of a quadcopter by restricting its ability to fly, but allowing it to rotate around its three main axes. The orientation model of a quadcopter is also presented focusing on the experimental estimation of the thrust and drag coefficients. A PID-based attitude controller is designed and discretized in order to implement it in an embedded system. Simulation results and initial experimental tests are included showing the response of the multi-rotor experimental testbed and the performance of the controller. | This article presents a video system to focus an object of interest in the field of view by means of a stereo robotic head. The system relies on a new hierarchical segmentation technique that split the stereo pair into regions in a combined way. After segmentation is achieved, resulting regions in both images are implicitly related by a set of links and, consequently, their disparity can be estimated. Then, the cameras vergence is changed according to the estimated dispar- ity until the object of interest is focused. The system has proven to be robust against mild noise and illumination changes. Its main advan- tage is that calibration is not a critical issue for the system to work. | eng_Latn | 28,953 |
Polymorphism of tumour necrosis factor‐alpha (TNF‐α) at position –308 in relation to ankylosing spondylitis | In addition to HLA-B27, other genetic factors are thought to be involved in the pathogenesis of ankylosing spondylitis (AS). Because of the localization, in the proximity of the HLA-B locus, and the biological activities of TNF-alpha, we investigated the association between AS and a single base polymorphism located at position -308 of the TNF-alpha gene. An allele-specific polymerase chain reaction was developed to monitor this polymorphism. The frequency of the TNF-alpha alleles was determined in 66 AS patients and 37 healthy controls. The TNF-alpha allele frequency was not significantly different between AS patients and controls. | This paper deals with the transfer alignment problem of strapdown inertial navigation systems, using the velocity information and angular rate information of the ship. Major error sources for velocity-plus-angular rate matching is unmodeled ship body flexure dynamics. To reduce this alignment error, a two-stage strong tracking filter (TSTF) is designed. This TSTF is derived by merging the optimal two-stage Kalman filter with strong tracking filter. The ship body flexure is modeled as time-varying noise and its stochastic properties are estimated by TSTF. The simulation results show that the proposed method is effective to estimate the misalignment angles of the slave inertial navigation systems. | eng_Latn | 28,954 |
Numerical solution of non‐linear Klein–Gordon equations by variational iteration method | In this paper, numerical solution of non-linear Klein–Gordon equations with power law non-linearities are obtained by the new application of He's variational iteration method. Numerical illustrations that include non-linear Klein–Gordon equations and non-linear partial differential equations are investigated to show the pertinent features of the technique. Copyright © 2006 John Wiley & Sons, Ltd. | A covariance analysis is presented for a differential GPS-based technique for satellite tracking and gravity recovery to be demonstrated on Topex in the early 1990's. The technique employs data from an ensemble of repeat ground tracks to recover a unique satellite epoch state for each track and a set of invariant local gravity parameters common to all tracks. For satellites above about 800 km altitude, where gravity modeling is the dominant systematic error, averaging of random error over many arcs and adjustment of the gravity model reduces the final satellite position error. The local gravity parameters can then be used to produce a refined global gravity model. The analysis indicates that errors ranging from 5 to 8 cm in Topex altitude and 0.05 to 0.2 mgal for the gravity field can be achieved, depending on the number of repeat arcs used. | eng_Latn | 28,955 |
A study of the use of ultraviolet-ozone cleaning for reduction of the defect density on molecular beam epitaxy grown GaAs wafers | A problem with molecular beam epitaxy growth of semiconductors is the presence of defects. Since most of them originate at the substrate/epitaxial interface, special attention must be given to the treatment of the surface before growth. It must be clean on an atomic scale. This study has found that a combination of ultraviolet–ozone treatment and chemical etching produces the lowest defect density in the grown layer. | Underwater gliders are often used to perform in-situ measurements of oceanographic systems. In particular, there have been a number of recent efforts to use their state estimation capabilities in order to infer physical oceanographic process dynamics, such as modeling currents and eddies. Such inference requires that the dead-reckoning systems used on the vehicles, typically hand-tuned Extended Kalman Filters (EKFs), to be tuned consistently, which can be tedious and burdensome, especially across large numbers of trials. In this work, we describe a method to automatically tune state estimation hyper-parameters used in underwater glider EKFs, that does not require ground truth estimates. This automation is achieved by taking advantage of the normalized innovation squared (NIS) metric, which can be used inside of the objective function of various optimization methods. In this paper, we demonstrate its validity in simulated environments and provide initial results for its use on fielded glider data. | eng_Latn | 28,956 |
The Design of Interpolation Set in Rolling-gear Machine | The principle and equipment for slotting large gear hobbing machine is put forward in this article.How to apply interpolation set is discussed.And then,this method is compared with traditional machining method. | In order to solve the dynamic positioning accuracy testing of maritime GPS equipment,a method of using high-precision total station to track satellite positioning equipment dynamicly for dynamic positioning accuracy assessment was proposed.The testing baseline data collection and processing,and converting the GPS positioning data to test benchmark,by use of attitude data provided by inertial navigation equipment,were discussed.Furthermore,the system error was analyzed.Finally,the experiment result showed that the new method was effctive. | eng_Latn | 28,957 |
Spin asymmetries of the nucleon experiment | The Spin Asymmetries of the Nucleon Experiment (SANE) is a measurement of the double spin asymmetries A1(x,Q),A2(x,Q) and the spin structure functions g1(x,Q),g2(x,Q) over a broad kinematic range of Bjorken scaling variable x, 0.3 < x < 0.8, for range of four-momentum transfer 2.5 < Q2 < 6.5GeV 2. The moments of g1(x,Q) and g2(x,Q) will provide access to the higher twists related to quark-gluon interactions and calculable in confinement models of QCD. The experiment measured inclusive double spin asymmetries using the TJNAF polarized electron beam with energies of 4.7 and 5.9 GeV, which was scattered off the UVa polarized solid NH3 target in both parallel and transverse configurations. The experiment took place from January to March of 2009. We will discuss the physics motivation for SANE and current status of the analysis. | To analyze the relationship between the deceleration-free servo system's tracking error and electrostatic gyroscope monitor's six-time calibration,the reason and the solution method of six-time calibration working abnormally are given.By analyzing the academic relationship among the deceleration-free servo system's tracking error,h angle transformation and azimuth angle,a new six-time calibration method is proposed.In this method,the equatorial gyroscope and polar gyroscope are calibrated at the different time according their azimuth angles.By several dynamic tests,the method is proved effectively with 100% success rate when the deceleration-free servo system's tracking error or the ship rocking is over the mark.By using the method,the electrostatic gyroscope monitor is more applicable in the ships. | eng_Latn | 28,958 |
DFT-based frequency acquisition algorithm for large carrier offsets in mobile satellite receivers | A new automatic frequency control (AFC) algorithm suitable for digital satellite receivers to counter-act large carrier offsets is presented. The proposed two-step scheme uses a low-resolution discrete complex Fourier transform (DFT) for coarse acquisition and a conventional feed forward (FF) estimator for fine tracking. Results from computer simulations are provided to demonstrate the capability of the algorithm. | This paper deals with the transfer alignment problem of strapdown inertial navigation systems, using the velocity information and angular rate information of the ship. Major error sources for velocity-plus-angular rate matching is unmodeled ship body flexure dynamics. To reduce this alignment error, a two-stage strong tracking filter (TSTF) is designed. This TSTF is derived by merging the optimal two-stage Kalman filter with strong tracking filter. The ship body flexure is modeled as time-varying noise and its stochastic properties are estimated by TSTF. The simulation results show that the proposed method is effective to estimate the misalignment angles of the slave inertial navigation systems. | eng_Latn | 28,959 |
Detection method for the cube right angle errors with plane interferometer | A method for measuring cube right angle errors with planar interferometer is introduced.Laser interferometer measurement method has high precision and high sensitivity.A cube bearing fixture is fabricated to ensure the measuring light can outgo from the incident plane after reflection in the cube.When the outgoing light coincides with parallel measuring light,interference is formed and cube right angle errorsΔ90°are measured with planar interferometer.Meanwhile,indicators such as surface flatness of the cube and defects in the glass can also be judged at the same time.The method equates to prism lens interferometer in the cube right angle errors measuring. | By labrary analysis of coal seam roof and bottom rock samples which are obtained from Qinshui coalfield,the results are used to regression analyse with well logging visual resistivity and naturalγ,and then the regression equation is obtained,furtherly,using the equation to whole coalfield for forecasting overall distributive tendency of rock intensity.Ithas guidance in mine shaftdesign and safe production. | eng_Latn | 28,960 |
3D Numerical Simulation Analysis of Passive Drag Near Free Surface in Swimming | The aim of this work is to build a 3D numerical model to study the characteristics of passive drag on competitive swimmers taking into account the impact of the free surface. This model solves the 3D incompressible Navier-Stokes equations using RNG k-ɛ turbulence closure. The volume of fluid (VOF) method is used to locate the free surface. The 3D virtual model is created by Computer Aided Industrial Design (CAID) software, Rhinoceros. Firstly, a specific posture of swimming is studied. The simulation results are in good agreement with the data from mannequin towing experiments. The effects of a swimmer’s arms and legs positions on swimming performance are then studied. Finally, it is demonstrated that the present method is capable of simulating gliding near the free surface. | This research is funded by the Environment Agency and United Utilities whose support is gratefully acknowledged. Some of the methods employed in this work have been tested on the background of the results obtained in MorphSed (www.morphsed.es), a research project funded by the Spanish Ministry of Economy and Competiveness and the European Regional Development Fund Scheme (FEDER; CGL2012-36394). The second author is funded by a Ramon y Cajal Fellowship (RYC-2010-06264). Authors acknowledge the support from the Economy and Knowledge Department of the Catalan Government through the Consolidated Research Group ‘Fluvial Dynamics Research Group’ (2014 SGR 645). The authors thank Manel Llena from the University of Lleida for his help and contribution to the camera calibration experiments. We are also grateful to the three anonymous reviewers and the editors for their comments that greatly improved the manuscript. | eng_Latn | 28,961 |
Indirect measurement technology of locating points based on correction | To solve the locating points'offset problem in the off-line program process of the automatic drilling riveting system,the indirect measurement method of the locating points based on correction was proposed.Firstly,the locating points were obtained by Agent technology.And a visual interactive definition platform was set up to define the locating points interactively.Secondly,the AUTOMATION interface was applied to correct the locating points and a template document was used to manage the global offset of the locating points.Then,the final locating points were determined by linear programming.Finally,an example of sheet metal parts was presented to demonstrate the implementation of the proposed method. | This paper analyses the causationes that influence the precision of the weighing system.Introduces the characteristics of the chip ADS1230 and designing of hardware circuit in weighing system.This design uses the most extensive and mature technology AT89C51 chip microcontroller and the resistance strain weighing sensor chip.The system has many characteristics-rapid weighing,exact and steady data,ease using,high anti-jamming ability etc. | eng_Latn | 28,962 |
Particle Filter SLAM with High Dimensional Vehicle Model | This work presents a particle filter method closely related to Fastslam for solving the simultaneous localization and mapping (slam) problem. Using the standard Fastslam algorithm, only low-dimensional vehicle models can be handled due to computational constraints. In this work, an extra factorization of the problem is introduced that makes high-dimensional vehicle models computationally feasible. Results using experimental data from an unmanned aerial vehicle (helicopter) are presented. The proposed algorithm fuses measurements from on-board inertial sensors (accelerometer and gyro), barometer, and vision in order to solve the slam problem. | In this paper, the results of a series of elastoplastic large deflection analyses on a specific cylindrical shell part of the ship hull girders under inplane compression is reported. Nonlinear finite element method is applied in the calculations. It is revealed that the assumption of elastic-perfectly plastic behaviour for this part of the ship hulls is not realistic and may result in very optimistic predictions of the ship hull overall strength. | eng_Latn | 28,963 |
Engine and aircraft engine assembly comprising; and a device for fixing it | The present invention relates to an engine assembly for an aircraft (1), the assembly will be and a device (4) for fixing the engine and the engine (6), the fixation device is an aircraft wing system and engine and it is designed to be placed, yet rigid structure (8) between, it comprises a means for securing the engine to the rigid structure, the securing means the first fastener (10 ) and it is constructed from a second fastener (12). The present invention, first fastener is respectively provided two lateral fastener halves attached to the engine of the fan casing (18) and (10a), and a second fastener engine centerline casing ( attached to the front of the 22), wherein the are. | In this paper, robust actuator fault reconstruction for satellite attitude control systems (ACSs) in the presence of space environmental disturbances and actuator faults is investigated via a learning observer (LO). First, a nonlinear mathematical model of the satellite ACS satisfying Lipschitz constraint is established; then an LO is constructed to achieve robust reconstruction of satellite attitude angles, attitude angler velocities and actuator faults at the same time. Further, sufficient conditions for the robust stability of the LO are explicitly provided in this paper. The design problem of the proposed LO is formulated into a convex optimization problem in terms of linear matrix inequalities (LMIs) that can be directly solved using the LMI toolbox of MATLAB. At last, simulation studies on a satellite example are performed to illustrate the effectiveness and applicability of the presented LO-based fault-reconstructing strategy. | eng_Latn | 28,964 |
Calibration and error analysis of a Ka-band fully polarimetric radiometer built with wideband microstrip correlator | In this paper we present calibration and error analysis of our Ka-band fully polarimetric radiometer, the radiometer used a wideband microstrip correlator. The calibration method is based on the tri-polarimetric calibration technique of Gasiewski and Kunkee, but is extended to provide the calibration of the fourth Stokes parameter using a retarder plate. A method to determine the phase shift of the retarder plate is introduced, a calibration matrix inversion technique is described as well. The calibration uncertainties and calibration error analysis are discussed at last. | Abstract According to the method described in reference [1], we have designed a series of corrector systems for Cassegrain telescopes automatically with an electronic computer. The calculations were carried out under the following two conditions: the primary and secondary mirrors have strictly conical surfaces, and the telescope is strictly free from third-order spherical aberration when the corrector systems are taken off. Results in this papercan be converted proportionally to real telescopes of any aperture, while the aberrations expressed in seconds of arc remain unchanged. | eng_Latn | 28,965 |
Fiber in-line Fabry-Perot interferometer for simultaneous measurement of reflective index and temperature | A fiber in-line Fabry–Perot interferometer is presented. The sensing head ::: consists of a micro ellipsoidal air cavity and a small section of solid-core photonic ::: crystal fiber. The reflective index (RI) and temperature can be interrogated ::: simultaneously through a fast Fourier transform and by tracing the dip wavelength shift ::: of the reflective spectrum. Experimental results show that the RI amplitude and ::: wavelength sensitivities are 5.30/RIU and 8.46×10−1 nm/RIU in the range from ::: 1.34 to 1.43, and the temperature amplitude and wavelength sensitivities are ::: 6.8×10−4/°C and 2.48×10−3 nm/°C in the range from 15°C to ::: 75°C, respectively. Easy fabrication, a simple system, and simultaneous measurement make ::: it appropriate for dual-parameter sensing application. | Development of an indirect view system for vehicles requires an appropriate method of its evaluation to achieve the purpose. Conventionally, evaluation by view area has been most frequently used in carrying out such development, without any method for evaluation by visibility. Under the circumstances, research was carried out to establish methods of evaluation by quantifying the size and distortion of the indirect view image. Using the results of this research work, a series of model tests were repeated to arrive at a periscope mirror system. This system excels all other mirror systems in image size, uniformity in distortion, view range, continuity with direct field-of-view and ease of use by drivers, and offers the best means of providing indirect view in heavy vehicles. (TRRL) | eng_Latn | 28,966 |
Boresight Calibration of Mobile Laser Scanner Using an External Fixture | Abstract The boresight misalignment of a mobile laser scanning system is a major source of error for point cloud data and cannot be measured directly. This paper presents a new boresight calibration method for a mobile laser scanner system that uses an external fixture with a simple checkerboard pattern. The boresight angles are determined by minimizing the differences between the measured relative distances of the intersection points of the squares in a checkerboard fixture with the corresponding actual distances in the fixture. Experimental results from scanning the checkerboard pattern on the fixture show that the calibrated values of the boresight angles match the manufacturer’s values within 0.22 cm. Using this simple checkerboard fixture in the field prevents surveyors from having to rely on roadway features or setting control targets and provides for an alternative approach for the boresight calibration of a mobile laser scanner system. | Abstract According to the method described in reference [1], we have designed a series of corrector systems for Cassegrain telescopes automatically with an electronic computer. The calculations were carried out under the following two conditions: the primary and secondary mirrors have strictly conical surfaces, and the telescope is strictly free from third-order spherical aberration when the corrector systems are taken off. Results in this papercan be converted proportionally to real telescopes of any aperture, while the aberrations expressed in seconds of arc remain unchanged. | eng_Latn | 28,967 |
Dynamic balancing of small gyroscope rotors | A DIRECT METHOD1 of balancing is generally possible for any type of rotor provided it can be run in a special fixture for the measurements. However, some rotors due to large size or other restrictions can be run only on their permanent mountings and balancing usually requires more or less “trial and error” testing. On the other hand, certain rotors of the first group that are small in size and may be run in special fixtures, impose unusual obstacles which make it difficult to apply the well-known principles to produce a rational method of dynamic balancing. This paper is devoted to a description of the solution of such a balancing problem. | This paper analyses the causationes that influence the precision of the weighing system.Introduces the characteristics of the chip ADS1230 and designing of hardware circuit in weighing system.This design uses the most extensive and mature technology AT89C51 chip microcontroller and the resistance strain weighing sensor chip.The system has many characteristics-rapid weighing,exact and steady data,ease using,high anti-jamming ability etc. | eng_Latn | 28,968 |
Stereo accuracy for collision avoidance | In a stereo configuration, the measurable disparity values are integral, therefore the measurable depths are discrete. This can create a trap for a safety system whose purpose is to estimate the trajectory of a moving object, and issue an early warning. Accuracy of this estimation is determined by the samples which have different measurable depths. Change in measurable depths becomes obvious for closer regions, but due to the limited extent of the stereo common field of view for these regions, the object might not be in the common field of view. A velocity estimation algorithm has been created, which takes into account the constraints of stereo, while accurately estimating the object's trajectory. From examination of various scenarios, we show that a stereo system could be misleading while estimating the object trajectory: it could predict that an object on a collision course is ‘safe’. | Abstract According to the method described in reference [1], we have designed a series of corrector systems for Cassegrain telescopes automatically with an electronic computer. The calculations were carried out under the following two conditions: the primary and secondary mirrors have strictly conical surfaces, and the telescope is strictly free from third-order spherical aberration when the corrector systems are taken off. Results in this papercan be converted proportionally to real telescopes of any aperture, while the aberrations expressed in seconds of arc remain unchanged. | eng_Latn | 28,969 |
Superfine comminution of Glycyrrhiza uralensis roots by vibration mill | Objective: To discuss the mechanism of superfine comminution of traditional Chinese medicine (TCM) at low temperature. Method:Glycyrrhiya uralensis roots were at room superfinely comminuted temperature and at low temperature by cryogenic vibration mill;The superfine powders were observed and analyzed by laser particle size analyzer and SEM. Result: The powder processed at low temperature was of smaller effective diameter and narrower size distribution and was also with smoother surface and smaller angle of repose. Conclusion: The G. uralensis roots could be superfinely comminuted with high efficiency and simple procedure by vibration mill at low temperature. [ | Underwater gliders are often used to perform in-situ measurements of oceanographic systems. In particular, there have been a number of recent efforts to use their state estimation capabilities in order to infer physical oceanographic process dynamics, such as modeling currents and eddies. Such inference requires that the dead-reckoning systems used on the vehicles, typically hand-tuned Extended Kalman Filters (EKFs), to be tuned consistently, which can be tedious and burdensome, especially across large numbers of trials. In this work, we describe a method to automatically tune state estimation hyper-parameters used in underwater glider EKFs, that does not require ground truth estimates. This automation is achieved by taking advantage of the normalized innovation squared (NIS) metric, which can be used inside of the objective function of various optimization methods. In this paper, we demonstrate its validity in simulated environments and provide initial results for its use on fielded glider data. | eng_Latn | 28,970 |
Ranging Accuracy and Doppler Tolerance of CW Signal Based on Pseudo-Random Code Bi-Phase Modulation | Ambiguity function method is used to study the ranging and Doppler tolerance performance of CW signal based on pseudo-random code bi-phase modulation (PRCBPM). Its ranging resolution and Doppler tolerance confine are calculated, the ranging performance and Doppler tolerance capability are simulated by using the software of Matlab and the influence factors are analyzed. The simulation results are consistent with the calculation values. The results show that the ranging precision of PRCBPM signal depends on the code width and is more improved with the narrower code width, and that the Doppler tolerance performance lies on and is inverse proportion to the product of code width and code length. | AbstractAn exact solution is established pertaining to the problem of undamped free vibration of a thin circular plate resting on a Winkler foundation with variable subgrade modulus. The solution is performed by applying the infinite power series method. Moreover, the solution procedure is demonstrated through an illustrative example, wherein the general frequency equation is derived for two different boundary conditions. The correctness of the solution is also verified using results available in the literature. Finally, it is shown that the proposed method of solution is directly applicable to the more-general problem of circular plates on a variable-modulus Pasternak-type foundation. | eng_Latn | 28,971 |
Research on Focus and Level System for Stepper Based on Linear Array CCD | A focus and level system of stepper based on linear array CCD was introduced,its testing and controlling principles were discussed.The optical structure of focus and level system was introduced,and a mathematical model for single-point measurements of height and focusing and leveling was set up. | The invention relates to a method and a system for diagnosis of one or more rail vehicles, which each at least comprise at least one measuring device for detecting measured values of a measured variable, comprising the following method steps: - acquiring measurement values by means of at least a measuring device at least one rail vehicle, - transmitting the measured values from the rail vehicle to a route-side control center, - evaluating the measured values in the control center by means of a predetermined algorithm, and - providing a result of the evaluation for output. | eng_Latn | 28,972 |
Conformation of α,α,α′‐Trisubstituted Cyclododecanone | Ten α,α,α′-trisubstituted cyclododecanones were synthesized and characterized by elemental analyses, infrared, 1H NMR and 13C NMR spectra, and X-ray diffraction. NMR data could not give conformational information clearly, but some of their ring skeleton conformations of cyclododecanone moiety were showed to remain the unchanged [3333]-2-one conformation with little distortion, while the others were changed to the [3324]-2-one conformation in their crystal structures. These are consistent with the results of molecular mechanics calculation with Sybyl 6.9 software and Tripos force field, and semi-empirical quantum calculation with AM1 method in Gaussian 98 software. Two geminal substituting groups are located at α-corner carbon atom, and the third group is at α-side-exo carbon atom in both conformations. Both [3333]-2-one and [3324]-2-one conformations are present in a dynamic equilibrium in the solution, but only one preferred conformation exists in the crystal solid. | The paper mainly researches and analyses the geometric quality of three-line array CCD(TLC)imagery of ZY-3 satellite,and introduces the processing flow of geometric positioning relative to ground of three-line array CCD imagery.After a brief description of the strict geometric imaging model of three-line array CCD imagery of ZY-3 satellite,the paper establishes the error compensation model according to the exterior orientation angle elements and the geometric calibration of camera orthogonal.After the system calibration on the ground,by using different times imagery and high precise ground control points,a test is conducted,and the plane precision of the imagery is analysed and evaluated.The results show that without Ground Control Points,the external positioning accuracy of three-line array CCD imagery of ZY-3 satellite is better than 6 pixel,and the internal geometric deformation less than 1.5 pixel. | eng_Latn | 28,973 |
Automated digital benchtop calibration system for hydrophone arrays | A calibration system is described which can measure the complex sensitivity and directivity patterns of hydrophone arrays, such as sonobuoy arrays, in which the hydrophone elements are individually accessible. These arrays are often deployed over a great distance in the ocean. Calibrating them under free‐field conditions would be an extremely difficult task. The system described here allows for their calibration on a benchtop. The entire calibration system is controlled by a computer and requires minimal operator intervention. The computer algorithm is also applicable to hydrophone arrays which do not have individually accessible elements. Results are presented which compare measured directivity patterns with theoretical directivity patterns calculated from the measured complex sensitivities of the individual array elements. | This paper analyses the causationes that influence the precision of the weighing system.Introduces the characteristics of the chip ADS1230 and designing of hardware circuit in weighing system.This design uses the most extensive and mature technology AT89C51 chip microcontroller and the resistance strain weighing sensor chip.The system has many characteristics-rapid weighing,exact and steady data,ease using,high anti-jamming ability etc. | eng_Latn | 28,974 |
Trajectory of a Horizontally Diffused Plane Wall Jet in a Non-isothermal Ceiling Slot-ventilated Enclosure | Indoor air quality can be improved according to the airflow pattern in a confined enclosure which is controlled by the trajectory of diffused air-jet. A theoretical equation describing the trajectory of horizontally diffused plane wall jet in a non-isothermal ceiling slot-ventilated enclosure was derived in this study. Archimedes number was demonstrated to be the dominant variable for the trajectory of plane wall jet. The vertical displacement y was proportional to x5/2, the horizontal displacement in the trajectory of a plane wall jet. Both the devised model and the model by Etheridge and Sandberg (1996, Building Ventilation: Theory and Measurement. John Wiley & Sons Ltd., West Sussex, England) were compared with test data from previous research. The results of the comparisons between these two models showed that the model derived from this study with a smaller value of means squared prediction error is a better predictor for the trajectory of a plane wall jet. | Abstract : The operational conditions of two spacecrafts performing a rendez-vous in geostationary orbit are given with the relative motion equation and the relevant control law. The concept of position, velocity and attitude measurement of the chaser vehicle with respect to the target one is given in order to allow the evaluation of the measurement errors. Simulations show the effect of the errors sources on the flight path of the approaching vehicle and point out the necessity of a good matching between the sensor accuracy and the minimum impulse level of the actuation system. (Author) | eng_Latn | 28,975 |
GNSS bias correction for localization systems | This paper deals with using of low-cost Global Navigation Satellite System (GNSS) sensors in a localization process for an autonomous guidance system of mobile robots. Generally, this process is made using a Kalman Filter (KF) to fuse information coming from different sensors. But as GNSS error is an unpredictable stochastiscal process, the localization estimated by the KF becomes unreliable. To solve this problem, the error of a cheap GNSS receiver is analyzed. Then, an AutoRegressive process (AR process) is used to establish a reliable prediction model. A second problem of GNSS systems concerns the disturbances in the observation of satellites. To detect this disturbance, we use a condition based on the Mahalanobis distance. This model and condition are taken into account in the localization system to improve its accuracy and its reliability. To finish, many experimental results show the improvement of GNSS localization system using our modeling and disturbance detection process. | The servo design and model of the W. M. Keck telescopes autoguider is presented. Telescope servo models often do not include the guider loop and therefore do not take advantage of traditional control analysis and test techniques to improve performance. Guide camera dynamics, computational and transport lags, and compensation networks are discussed. A means of measuring the actual frequency response characteristics of the guide loop is presented and the results are compared to those predicted by the model. Guide performance as a function of integration time is illustrated. An improved compensation network is developed and its performance examined.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only. | eng_Latn | 28,976 |
An adaptive observer for dynamical ship position control using vectorial observer backstepping | In this paper, we propose an adaptive observer for dynamically positioned ships, that can be used together with the controller shown by Fossen and Grovlen, to design an observer-based adaptive control scheme. The resulting closed-loop system is globally asymptotically stable with respect to the ship positions and velocities, and globally stable with respect to the unknown parameters. | A new modeling method based on sample data is described in this paper,through physics and sample date analysis on displacement vs.voltage characteristics of x-y plane of cylindrical piezoelectric scanner used in scanning probe microscope(SPM).Through sample data statistical analysis,and considering the error factors such as scan speed,scan angle,nonlinearity and coupling,a model represented by a binomial plus some error expressions is constructed.A nonlinearity correction expression based on the model is deduced.With the software Matlab this nonlinearity correction is simulated.The result of simulation indicates that it can eliminate the errors effectively.The ascendency of the method is that there are no polarization mechanism analysis and fewer number of model parameters.The method is practical applied to engineering. | eng_Latn | 28,977 |
High Temperature Integrated and Flexible Ultrasonic Transducers for NDT | Integrated (IUTs) and flexible ultrasonic transducers (FUTs) are presented for NDT at high temperatures. These transducers are made of sol-gel spra yed piezoelectric thick (> 40µm) ceramic films. The ceramic materials are lead-zirconate-titanate, bi smuth titanate and lithium niobate which are for thickness measurement up to 150°C, 400°C and 800°C, respectively. T he IUT can be also deposited onto one end of a long ultrasonic delay line to perform non-destructive testing at the other end at even higher temperatures. FUTs made of bismuth titanate films onto thin stainless steel foils are also used for thickness measurements at 300°C with a high temperature coupla nt sandwiched between the FUT and a steel substrate. All experiments at high temperatures wer e performed in pulse-echo and ultrasonic echoes with signal to noise ratios above 20dB were obtained. The cen tre operation frequencies of both IUTs and FUTs range from 4.4MHz to 10.7MHz. | This paper deals with the transfer alignment problem of strapdown inertial navigation systems, using the velocity information and angular rate information of the ship. Major error sources for velocity-plus-angular rate matching is unmodeled ship body flexure dynamics. To reduce this alignment error, a two-stage strong tracking filter (TSTF) is designed. This TSTF is derived by merging the optimal two-stage Kalman filter with strong tracking filter. The ship body flexure is modeled as time-varying noise and its stochastic properties are estimated by TSTF. The simulation results show that the proposed method is effective to estimate the misalignment angles of the slave inertial navigation systems. | eng_Latn | 28,978 |
Bio-inspired navigation based on geomagnetic for the autonomous underwater vehicle | Dependence on the prior magnetic map become one of the key problems which restrict the development of the geomagnetic navigation. This paper inspired from the animal navigation behavior which dispense with the priori geomagnetic map. First, we generalize the bio-inspired navigation process as a multi-objective problems. Then, present a stress evolution search AUV navigation model for the particularity of geomagnetic navigation, which make multi-objective problem solving search combine with navigation movement to achieve the purpose of navigation. Finally, compared the present model with a gradient descent model with part priori geomagnetic map. The simulation results show that the proposed algorithm allows the AUV to navigate efficiently using geomagnetic information without prior map. The proposed algorithm offers insights into the research and application of the biologically inspired geomagnetic navigation. | This article presents a video system to focus an object of interest in the field of view by means of a stereo robotic head. The system relies on a new hierarchical segmentation technique that split the stereo pair into regions in a combined way. After segmentation is achieved, resulting regions in both images are implicitly related by a set of links and, consequently, their disparity can be estimated. Then, the cameras vergence is changed according to the estimated dispar- ity until the object of interest is focused. The system has proven to be robust against mild noise and illumination changes. Its main advan- tage is that calibration is not a critical issue for the system to work. | eng_Latn | 28,979 |
Autoguider servo design and testing of the W. M. Keck Telescope | The servo design and model of the W. M. Keck telescopes autoguider is presented. Telescope servo models often do not include the guider loop and therefore do not take advantage of traditional control analysis and test techniques to improve performance. Guide camera dynamics, computational and transport lags, and compensation networks are discussed. A means of measuring the actual frequency response characteristics of the guide loop is presented and the results are compared to those predicted by the model. Guide performance as a function of integration time is illustrated. An improved compensation network is developed and its performance examined.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only. | AbstractThis case study analyzes a nocturnal mesoscale convective system (MCS) that was observed on 25–26 June 2015 in northeastern Kansas during the Plains Elevated Convection At Night (PECAN) pro... | eng_Latn | 28,980 |
Sensor network based device free trespasser detection and localisation | Device free detection and localization is a promising and a very practical research area where installation of expensive sensors and/or tagging the intruder is not feasible. This paper reports a mesh network developed for device free trespasser detection. We use the Received Signal Strength Indicator (RSSI) measurements of the wireless links within the mesh as the sole sensing mechanism. A fingerprint of RSSI measurements characterizes the environment under normal conditions including multi-path effects. A technique to differentiate RSSI variations due to trespassers from those due to multi-path effects is demonstrated. The results of the experiments conducted in an outdoor environment have verified that the proposed method can be used to detect trespassers successfully. The reliability of the detection is improved by cross-correlating RSSI variations among the multiple links in the mesh. The ability to extend the system for localization is also investigated. | A new modeling method based on sample data is described in this paper,through physics and sample date analysis on displacement vs.voltage characteristics of x-y plane of cylindrical piezoelectric scanner used in scanning probe microscope(SPM).Through sample data statistical analysis,and considering the error factors such as scan speed,scan angle,nonlinearity and coupling,a model represented by a binomial plus some error expressions is constructed.A nonlinearity correction expression based on the model is deduced.With the software Matlab this nonlinearity correction is simulated.The result of simulation indicates that it can eliminate the errors effectively.The ascendency of the method is that there are no polarization mechanism analysis and fewer number of model parameters.The method is practical applied to engineering. | eng_Latn | 28,981 |
By using a surrounding object as a dynamic binding, reduction and image enhancement radiation dose in tomography | Image reconstruction methods are described where the characteristics of the surroundings of the patient in the scanner image field are used as supplemental information in the reconstruction process to reduce the dose, reduce scan times, scan number and/or improve the image quality of the reconstructed image. | It is known that the loading state of the radial bogie of tilting train the first in China is complex as well as its structure. In this paper, first the optimum algorithm of famous I-DEAS software was discussed then the frame of radial bogie of tilting train was optimized. In the optimum design model not only the stress restraints but also the displac ment retraints and design variables limits have been put in. results of the frame of radial bogie of tilting train is very good not only the local stress centralization has been reduced but also the stiffness requirement has been met. | eng_Latn | 28,982 |
Similar Single-Difference Methodology and Results Analysis for SlopObjects Deformation Monitoring in Three Gorge Area | According to the characteristics of the high precise GPS deformation monitoring, basing on the first period observation results of the monitoring network,the similar single-difference model of solving GPS monitor point deformation information at single epoch is built,and the receivers'antenna phase center offsets are discussed.This model avoids the troublesome problem of cycle slip detecting and repairing,and is not only applicable to the static and dynamic monitoring modes, but also suitable for the single receivers.The correctness of the similar single-difference model is verified with the practical data in Three Gorge Area. | This paper firstly introduces the mathematical model of stepped frequency and MMW one dimensional range imaging technique.Secondly,the mathematical model of one dimensional range imaging for high range resolution MMW seeker when there is relative motion between the missile and the target is given.Using this mathematical model,the influence of missile-target relative motion on one dimensional range imaging is investigated by computer simulation.Finally,the value of the compensating error of this relative motion between the missile and the target is derived when one dimensional range imaging technique is used for target identification. | eng_Latn | 28,983 |
Fixed-Time Second Order Sliding Mode Guidance Law for Interceptors with Impact Angle Constraints | This paper presents a fixed-time second order sliding mode guidance law for interceptors with impact angle constraints. Firstly, the zero placement principle of close-loop system is carried out, and it make it convenient to adjust the state motion trajectory and improve the dynamic performance. Then, a novel fixed-time convergent super-twisting guidance law is proposed based on this principle. The efficiency of proposed algorithm are demonstrated through simulations under separated scenarios, and it is shown the desired impact angle can be guaranteed within fixed convergence time. | This paper presents the spectral dependences of the phase shift and the position of ::: the optic axis for three-, five-, and seven-component zero-order wave plates ::: fabricated from polymethyl methacrylate, which possesses artificially produced ::: anisotropy. Besides this, the dependences of the phase shift of the wave plates on ::: the angle of incidence of the rays and the temperature are presented, along with the ::: spectral dependence of the transmittance of the plates. | eng_Latn | 28,984 |
Three-dimensional accelerometer based on fiber Bragg gratings | A three-dimensional (3-D) fiber Bragg grating (FBG) based accelerometer is presented in this paper. A pair of differential FBGs with a partially overlapped spectrum is applied to each sensing axis resulting in a temperature compensated system. The inertial mass is attached between the two gratings and operates in a push-pull fashion. The reflected light power is modulated by acceleration and can be measured by a photo-detector. Our prototype has been validated both theoretically and experimentally. Static and dynamic tests show good linearity, high sensitivity, low uncertainty, and suit applications requiring a wide dynamic range. | In this paper, the structure characteristics of a transmitting device with stepped fit for high speed motorized spindles, and a detailed process of stress analysis to the shrink fitted joint in finite element analysis method is introduced. The reasonability of the structure design and reliability of the surplus joint are verified by analysis results. | eng_Latn | 28,985 |
Kind of Rotor Position and Speed Test Unit Based on AD2S83 | This paper raised a kind of rotor position and speed measurement module’s design principle and achieving method based on AD2S83 and resolver-digital converter. The module took the resolver as an angle position sensor, using AD2S83 to carry out resolving for sine and cosine signals. The main control unit adopted TMS320F2812 to realize real-time measurement and calculation of angle position and speed, acting as feed-back variable of speed loop and position to control the speed and position of servo system in real time. Experiment proves that the system is completely in conformity to design requirements, with features of stable and reliable working, simple hardware circuit, strong anti-interference, being able to work in long period worse environment. | Scars contracture, in four degree burns, reduces articulation mobility and it needs a dynamic orthotics intervention. The better ones are those that allow small steps of angle advance, up to 2°. The focus of this work is to show a new design capable to make an angle variation under 2° within 24 hours and a model to realize a treatment scheme. The device was built by the orthotics procedure using goniometry and trigonometric formulas. The idea was to use screw threaded systems designed for an angular extension under 2°. The easy way to build the modularity and the low production cost for this device recommends it for the use in clinical practice. | eng_Latn | 28,986 |
Transducer Arrangement for Radiated Power Prediction of Cylindrical Shells Based on Velocity Distribution | A method of transducer arrangements based on BEM is presented in this paper.Firstly,study the amount of transducers of cylindrical shell in axis and circumference directions,then,the optimum transducer arrangement is determined by comparing the prediction accuracy of the radiated sound power under different transducer arrangements.The results show that between 10 Hz and 125 Hz,the optimum numbers of transducers for axial and circumferential directions of a given modal are 5 and 12,respectively.It should be noted that while increasing the number of transducers above the optimum value does not signif icantly improve the sound power prediction accuracy,choosing a number lower than the optimum value does induce considerable calculation error.Also,this method is only applicable for low frequencies,and the distance between transducers can be confirmed with the corresponding 1/6 wavelength. | The invention relates to a method for improving the quality of CT image series, an arithmetic unit (10) and an X-ray CT system (1), wherein the following steps are performed: to detect scanning of an examination object (7) over a period of time which allows at least two temporally offset projection data sets of a same recording region (= Recording series), - - transforming the projection data sets in transition records for at least two spatial frequency areas, - calculating time compensation values of the transformation records for a part of the spatial frequency regions and replacing the matched values of the transform data sets with the calculated compensation values in the new transform data sets, always projection data superposable beams are compared, - transform the new transform data sets into new projection data sets, - reconstruction of image data sets based on the new projection data sets and - representation of the image data sets. | eng_Latn | 28,987 |
Nuclear spin precession in ferromagnets at small deviations from equilibrium taking account of nonlinearity | The free precession signal from nuclear spins in a ferromagnet is calculated. Arbitrary ratios between the halfwidth of microscopically inhomogeneous distribution of nuclear frequencies Γ and the characteristic frequency of Suhl-Nakamura interaction ω p are considered. It was found that the Lorentzian distribution function, which leads to precession doping independent of ω p in linear approximation, also plays a special role in considering nonlinear corrections. Namely, at small deviations of nuclear magnetization from equilibrium, the nonlinear correction leads only to an insignificant decrease of damping with increasing ω p | To analyze the relationship between the deceleration-free servo system's tracking error and electrostatic gyroscope monitor's six-time calibration,the reason and the solution method of six-time calibration working abnormally are given.By analyzing the academic relationship among the deceleration-free servo system's tracking error,h angle transformation and azimuth angle,a new six-time calibration method is proposed.In this method,the equatorial gyroscope and polar gyroscope are calibrated at the different time according their azimuth angles.By several dynamic tests,the method is proved effectively with 100% success rate when the deceleration-free servo system's tracking error or the ship rocking is over the mark.By using the method,the electrostatic gyroscope monitor is more applicable in the ships. | eng_Latn | 28,988 |
A MATHEMATICAL MODEL FOR CORRECTING THE PHOTOGRAPHIC COORDINATES DUE TO ORIENTATION ERRORS (AN APPLICATION IN CLOSE RANGE PHOTOGRAMMETRY) | Photographic coordinates x and y are fundamental data in analytical photogrammetry. At the same time these coordinates are functions of interior and exterior orientation elements, and contain some errors. Therefore some corrections and reductions are applied to the image coordinates measured in comparators before they are used in mathematical models. Some corrections and reductions related to the physical error sources inherent in photogrammetric system are applied to the comparator coordinates, but any correction related to the exterior orientation elements is not applied to these coordinates. In this study, a mathematical model has been proposed to correct the photographic coordinates due to the small errors of exterior orientation elements of camera. The data obtained a close-range test field have been used in the offered mathematical model and the results have been criticized. | IN ORDER TO ASSESS THE ABILITY OF 6-MONTH-OLD INFANTS TO MARE A PRINCIPLED PREDICTION ABOUT THE FUTURE MOTION OF AN OBJECT, 10 SUBJECTS WERE PRESENTED WITH A TOY MOVING ALONG 24 DIFFERENT PATHS OF OBJECT MOTION. EACH OF THESE PATHS MOVED A SMALL TOY ALONG A LINEAR TRAJECTORY AND BRIEFLY WITHIN REACH OF THE SUBJECT (SEE FIGURE). A VIDEO RECORD OF THE INFANTS WAS MADE FROM OVERHEAD AND SIDE POSITIONS, ALLOWING A RECONSTRUCTION OF THE THREE-DIMENSIONAL REACHING MOTIONS OF THEINFANTS. | yue_Hant | 28,989 |
Improved basic planar algorithm of vehicle guidance through waypoints by the line of sight | Guidance through waypoints is common for small autonomous marine vehicles. Guidance by the line of sight, the basic waypoint guidance algorithm, is very simple, computationally inexpensive, and flexible to sudden changes in the desired path specification. On the other side, the basic algorithm achieves unoptimal vehicle trajectory, ignores possible side disturbances as sea currents, and can even lead to deadlock situations. Therefore it should be improved to use in the real world applications. This paper introduces several such improvements: missed waypoint detection to prevent deadlocks, novel reference heading correction method to give smoother vehicle path in turns at waypoints, and sea current compensation method to cancel its influence. This improvements address the mentioned flaws of the basic algorithm, as is demonstrated by the simulations, and yet keep it simpler than is the case for the most used waypoint-derived guidance methods. | We develop methods for estimating the number of components in the Varshamov graph of a linear code and derive some new lower bounds on minimum distance for nonbinary codes. | eng_Latn | 28,990 |
Implementation of an Integrated, Portable Transformer Condition Monitoring Instrument in the Classroom and On-Site | The development of integrated, portable, transformer condition monitoring (TCM) equipment for classroom demonstrations as well as for student exercises conducted in the field is discussed. Demonstrations include experimentation with real-world transformers to illustrate concepts such as polarization and depolarization current through oil-paper composite insulation. The developed equipment has also been used to understand and illustrate the phenomenon of recovery voltage. Finally, the portability and robustness of the equipment enables students to collect data from transformers installed on-site for the purpose of validating the nature of curves obtained in real-world environments. | In estimating the state of thrusting/ballistic endoatmospheric projectiles for the end purpose of impact point ::: prediction (IPP), the total observation time, the wind effect and the sensor accuracy significantly affect the IPP ::: performance. First the tracker accounting for the wind effect is presented. Following this, based on the multiple ::: interacting multiple model (MIMM) estimator developed recently, a sensitivity study of the IPP performance with ::: respect to the total observation time, the wind (strength and direction) and the sensor accuracy is presented. | eng_Latn | 28,991 |
Successful Sidetracking of a Well Onshore Germany by Integration of 3D VSP Technology - A Case Study | After drilling a low-performing well onshore North Germany the borehole was used to conduct a 3D VSP. Main purpose was to improve the seismic image of the zone in the vicinity of the well in order to determine a new landing point for the envisaged sidetrack. This turned out to be the right choice despite difficulties arising from surface restrictions during acquisition and the complex geological setting. A thorough pre-survey planning is essential in order to achieve the set goals. The quality of the seismic image of the zone in the vicinity of the well was highly increased. This allowed a reliable prediction of a less-faulted acreage and suitable facies conditions. Furthermore, enhanced structural mapping workflows helped to provide improved interpretation results in order to minimize the risk of failure. | Tracking targets of interest is one of the major research areas in radar surveillance systems. We formulate the problem as incomplete data estimation and apply EM to the MAP estimate. The resulting filter has a recursive structure analogous to the Kalman filter. The advantage is that the measurement-update deals with multiple measurements in parallel and the parameter-update estimates the system parameters on the fly. ::: ::: ::: ::: Experiments tracking separate targets in parallel show that tracking maintenance ratio of the proposed system is better than that of NNF and RMS position error is smaller than that of PDAF. Also, the system parameters are correctly obtained even from incorrect initial values. Copyright © 2001 John Wiley & Sons, Ltd. | eng_Latn | 28,992 |
System identification using interval dynamic models | Motivated by the recent explosive development of results in the area of parametric robust control, this paper presents a new technique to identify a family of uncertain systems. The new technique takes the frequency domain input and output data obtained from experimental test signals and produces an "interval transfer function" that contains the complete frequency domain behavior with respect to the test signals. This interval transfer function is one of the key concepts in the parametric robust control approach and identification with such an interval model allows one to predict the worst case performance and stability margins using recent results on interval systems. The algorithm is illustrated by applying it to an 18 bay mini-mast truss structure. | Intelligent instrument has been widely used in various fields of life and production.When it was used with monitoring technology,the problem of measuring dangerous area can be solved efficiently.In this paper,character tilt and location were brought into focus.To solve tilt problem,rotation correction method was proposed based on the theory of perspective projection transformation.To solve location problem,sliding window method was proposed by using gray comparison.Experimental results show that these two methods can solve character tilt and location problem in character recognition of intelligent instrument. | eng_Latn | 28,993 |
Longitudinal instability of a continuous beam in a proton synchrotron | The results of a calculation of the threshold for longitudinal coherent instability of a continuous beam circulating in a proton synchrotron and constant energy are presented. A beam in an intermediate state — not bunched into bunches but not uniform over the azimuth — is said to be continuous. Such a beam moves outside (possibly, near) empty rf separatrices of the longitudinal sinusoidal electric field and has a ribbon portrait in the longitudinal phase plane. The computational method is used for the U-70 synchrotron at the Institute of High Energy Physics, where in the course of stochastic slow extraction of a circulating beam is continuous in the sense indicated. It bends around empty separatrices of the 200-MHz accelerating field and for several seconds interacts with the electromagnetic fields of the working oscillations of the disconnected resonators of the main accelerating system with frequency 5.5–6 MHz, which can result in a loss of longitudinal stability. | This paper presents three mathematical models for the correction of measurement errors of a prototype system designed for Large Scale Dimensional Metrology (LSDM) applications. The system, developed in the Quality and Industrial Metrology Laboratory of Politecnico di Torino, is based on the principles of photogrammetry and consist of a set of cameras wirelessly connected to a central unit for data elaboration and able to track the position of a hand-held contact probe. Due to its architecture the system is affected by several systematic error sources. This paper addresses some of them: the distortion of the lenses, the dimension of the probe tip and the kinematic of the probe. By means of the implementation of appropriate mathematical correction models, the overall system performance is significantly improved as shown by the proposed tests | eng_Latn | 28,994 |
Resolution Simulation about Sheltered Off-Axis Digital Holography in 2.52 THz | In the 2.52 Terahertz off-axis digital holography system, obstruction model is established according to the parameters of the camera. And we use a 0.2 mm resolution chart as the target to simulate the reconstructed image. | Mobile location estimation has attracted much interest over the past few years. The most challenging issues, which render to reach the required accuracy for the time-based location system, are multipath and non line-of-sight (NLOS) problems. This paper suggests the simple but robust techniques using biased Kalman filter to smooth and mitigate the NLOS effect for TOA measurements. The processed TOAs are then used for DTOA formulation and provided for location estimation. The further tracking stage is shown not to improve the accuracy much but to be necessary to smooth the mobile trajectory. The better accuracy for mobile location is suggested for future work by using the geographical information through searching the match between the path loss measured at multiple BSs and that estimated by ray-tracing techniques. | eng_Latn | 28,995 |
Potential of a wavelength sampling approach for profilometry by phase shifting interferometry | Abstract In this paper, we investigate how the field of application of phase shifting interferometry could be extended to the reconstruction of bidimensional phase maps of vibrating samples or of static samples located in a mechanically unstable environment. The possibility to perform instantaneous recording of the necessary phase shifted interferograms is discussed and a wavelength sampling approach is proposed. In that technique, the phase shift is introduced through a variation of the optical wavelength. The implications of that choice on the range of optical path differences that can be analysed are discussed. Since the necessary wavelengths can illuminate simultaneously the inspected sample, instantaneous acquisition procedures can be considered, providing that we dispose of a multi-spectral band image sensor for the parallel recording of the set of phase shifted interferograms. The choice of the phase computation algorithm is discussed and four of them are compared. An experimental set-up was built ... | This paper proposes a level set based coastline detection method by using the template initialization and local energy minimization. It can complete the sea-land boundary detection in infrared channel image. This method is an improvement on the traditional level set algorithm by using the information of GSHHS to optimize the initialization procedure, which can reduce the number of iterations and numerical errors. Moreover, this method optimizes regional energy functional, and can achieve the rapid coastline detection. Experiments on the IR image of FY-2 satellite show that the method has fast speed and high accuracy. | eng_Latn | 28,996 |
Attitude determination of autonomous underwater vehicles based on hydromechanics | Attitude determination is an important part for Autonomous Underwater Vehicles (AUVs) to achieve their designed mission. This paper presents a novel attitude solution based on the hydrodynamic model. The hydrodynamic parameters can be calculated by the known hydrological parameters. Meanwhile, the pressure information of AUV's surface can be measured by the pressure sensor array. The attitude information can be solved based on the values above. In order to verify the effectiveness of the proposed method, a multi-sensor integrated system is designed. The hydrodynamic parameters are solved by the finite element method. The quaternion model and EKF are selected to estimate the attitude information. Simulation results demonstrate that the proposed method is effective to improve the accuracy of the attitudes. | "The Floodplain Mapping Program and the Department of Transportation have already indicated that the reports automatically created by Accuracy Analyst ™ are acceptable...In other words, the use of this single package let us deliver more analytical results than we could manually, all in a standardized report that meets agencies' needs, while at the same time simplifying the process.". | eng_Latn | 28,997 |
Enhancing Weak-Signal Carrier Phase Tracking in GNSS Receivers | Examining the performance of the GNSS PLL, this paper presents novel results describing the statistical properties of four popular phase estimators under both strong- and weak-signal conditions when subject to thermal noise, deterministic dynamics, and typical pedestrian motion. Design routines are developed which employ these results to enhance weak-signal performance of the PLL in terms of transient response, steady-state errors, and cycle-slips. By examining both single and data-pilot signals, it is shown that appropriate design and tuning of the PLL can significantly enhance tracking performance, in particular when used for pedestrian applications. | Underwater gliders are often used to perform in-situ measurements of oceanographic systems. In particular, there have been a number of recent efforts to use their state estimation capabilities in order to infer physical oceanographic process dynamics, such as modeling currents and eddies. Such inference requires that the dead-reckoning systems used on the vehicles, typically hand-tuned Extended Kalman Filters (EKFs), to be tuned consistently, which can be tedious and burdensome, especially across large numbers of trials. In this work, we describe a method to automatically tune state estimation hyper-parameters used in underwater glider EKFs, that does not require ground truth estimates. This automation is achieved by taking advantage of the normalized innovation squared (NIS) metric, which can be used inside of the objective function of various optimization methods. In this paper, we demonstrate its validity in simulated environments and provide initial results for its use on fielded glider data. | eng_Latn | 28,998 |
Sensitivity analysis on dynamic response of railway vehicle and ride index over curved bridges | When a train passes over bridges, the magnitude of forces and accelerations is altered due to sudden changes in the track stiffness. These forces can change with the variation in operational parameters and are effective particularly in high-speed passenger trains, when studying ride index parameter. In addition, by increasing the speed, old bridge structures could fall into resonance, which has harmful consequences for both bridge and ride comfort index. Moreover, to harmonize the old bridges with the new operational conditions dynamic behavior of the vehicle and ride comfort need to be taken into account. In this paper, coupled vertical and roll vibration of a horizontally curved bridge are considered. During pass over the bridge, acceleration and ride comfort of a passenger vehicle are studied. The eccentric vertical and lateral forces are the major excitation sources in the analysis, an issue that is rarely noticed in the literature. A multi-body model of a normal wagon is built in three dimensions, pa... | Intelligent instrument has been widely used in various fields of life and production.When it was used with monitoring technology,the problem of measuring dangerous area can be solved efficiently.In this paper,character tilt and location were brought into focus.To solve tilt problem,rotation correction method was proposed based on the theory of perspective projection transformation.To solve location problem,sliding window method was proposed by using gray comparison.Experimental results show that these two methods can solve character tilt and location problem in character recognition of intelligent instrument. | eng_Latn | 28,999 |
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