Abstract:An improved mean backprojection algorithm based on an isopotential back projection algorithm of electrical impedance tomography (EIT) is presented by adopting the mean backprojection theory of computer tomography. The distance from the midpoint of an injected electrode pair to the midpoint of a measured electrode pair is taken as approximately the length of the projection routine which is introduced into the backprojection process. The positive and negative mean values of relative conductivities obtained by backprojection are computed. The final relative conductivities are the differences between the conductivity values obtained by backprojection and the corresponding sign mean value. If the results change sign, they are set to zero. Simulations and phantom experiments show that fewer artifacts are present in images reconstructed by mean backprojection algorithm than those reconstructed using the backprojection algorithm. The improved mean backprojection algorithm is more practical and effective than the backprojection algorithm.

Abstract:Based on an analysis of the characteristics of reactive power supplies and reactive loads, this paper presents a method for forming a lossless reactive network using an equivalent technique of modeling the branch admittance as a reactive power supply and the branch power loss as a virtual load. A downstream distribution matrix for a power system is constructed based on its reactive lossless network, and the analytical model and its algorithm for tracing reactive power flow (TRPF) is proposed. A method dealing with the abnormal downstream distribution matrix of active power flow also is discussed. The main advantage of the proposed method is that the matrix theory is used to analyze the TRPF model directly and no assumption on the flow distribution is needed. Case studies of the IEEE14Bus and IEEE30Bus systems demonstrate the accuracy and the validity of the proposed method.

Abstract:The alternating detail parameter (ADP) is a new parameter to represent waveform microdistortion. It is proposed to overcome the shortcomings of the traditional evaluation parameters, the normalized correlation coefficient (NCC) and the variation trend parameter. This proposal is based on the principle that two discrete waveforms are more similar if the ratio of their corresponding differentials is close to one. ADP is shown to be correct by power spectrum analysis. Simulation research demonstrated that ADP is valid for evaluating the effect on the denoised partial discharge signal by associating NCC with signal noise ratio.

Abstract:离散傅里叶变换(discrete Fourier transform,DFT)求解容型设备介质损耗角存在较大误差，对引起误差原因的频谱泄漏进行了详细分析和阐述，指出电网频率波动是造成测量介质损耗角不准确的主要因素，其带来的非整周期采样造成信号能量发散，各频率处信号能量相关性不为0。通过加余弦窗函数平滑信号陡度，对DFT相位频谱校正给出了2种不同的方法：加窗插值算法和离散频谱相位差校正法，并通过校正频率偏移量，在频谱峰值最大值处获得信号相位。通过Matlab仿真分析表明，2种算法实现方便，精度高，具有一定的实用性。

Abstract:To solve the problem of voltage waveform distortion of small single phase synchronous generators (SSPSG) when operating with loads, a method of timestepping finite element coupling with circuits is used to model the SSPSG and compute the SSPSG electromagnetic field with different damper winding connection types and using different damper winding materials when carrying rated loads. The voltage harmonics of each condition are compared and the influences of the damper winding analyzed. The results indicate that the SSPSG damper winding can weaken the negative sequence magnetic field in SSPSG, decreasing voltage waveform distortion. The damper winding connection manners play a much more important role than that of winding materials on weakening the negative sequence magnetic field in SSPSG.

Abstract:A new congestion management model based on highlow settlement is proposed for the electricity market. The model combines the transaction mechanism and congestion management to eliminate congestion in branches with the minimum equivalent increase in the system regulating fee. The equality constrains are the branch overloads, the generator sensitivities, and the corresponding adjustments, respectively. By introducing the Lagrange multiplier and a relaxation factor, the nonlinear programming problem with constraints can be translated into an unconstrained nonlinear programming problem. The regulating values of the generators thus can be obtained. The proposed algorithm is verified by a 6bus system.

Abstract:The efficiency of the 60QNY6.5 battery is studied by testing and theoretical analysis in order to improve the control precision of hybrid electric vehicles (HEVs) and the battery useful life. A rig for testing the NiMH batteries of HEVs is established. The data from experiments performed on the NiMH battery are analyzed. Based on the experimental results and the temperature of the batteries, internal resistance and electromotance models of NiMH batteries are proposed by functionfitting methods. The theoretic formula for battery efficiency is deduced by the operational principle of the battery and motor, which provides theoretical basis for dynamic optimizing technology of HEV system controlling strategy.

Abstract:Noise samples of motorcycles at different engine speeds taken at the position of the ear of a motorcycle operator are selected as the evaluation stimuli to investigate sound preferences of motorcycle sound quality. Subjective testing is carried out via the paired comparison method. Precise calculation of the misjudging rate is adopted to ensure test result reliability. Formulae between subjective preference scores and psychoacoustic parameters are obtained through linear correlation and multidimensional regression analysis. The results indicate that loudness and roughness are two predominant metrics influencing preference evaluation for motorcycle noise, and the nonlinear equation better describes the dependence of subjective preference scores on psychoacoustic parameters than the linear one.

Abstract:By analyzing the relationship between design ability and design time, mental workload, and design effect, an evaluation method of design ability is proposed. As far as the factors involved in such method are concerned, mental workload is measured by NASATLX (national aeronautics and space administrationtask load index) scale, design time is acquired with a special program, and design effect is scored by expert. Then, the time spent on new design tasks based on the evaluated ability level is predicted by using support vector machines, which is then compared with realmeasured time. The result shows that the predicted time is well accorded with the real time, which indicates that the evaluation method of design ability is valid.

Abstract:The incising ability of abrasive water jets submerged under water depend on their erosive capability. The turbulent flow characteristics of submerged abrasive water jets is experimented with using a system of abrasive water jets in a highpressure obturation container and a numeric photography system. The erosive capability of submerged abrasive water jets also is analyzed theoretically. We discuss the turbulence coefficient changes at various pump and ambient pressures. The results show that, under identical conditions, the extent of cavitation of submerged abrasive water jets exceeds that of cavitation water jets when the pressure is more than 5 MPa in a Wenqiu cavitation nozzle system. The cavitation ability of submerged abrasive water jets decreases due to the existence of abrasive particles.

Abstract:A study of the coefficient of sensitiveness between permeability and effective pressure of coal samples is conducted based on experimentation and analysis. Test results indicate that the permeability of coal samples drops rapidly as the effective pressure increases under a low effective pressure level. The variation relationship between them can be described by an exponential equation. The coupling mechanism of seepage in coal beds has not been completely made clear so far, and the coupling factors affecting the permeability of coal samples are too complex to describe. The coefficient of sensitiveness between the permeability of coal samples and effective pressure is defined accordingly so as to normalize these factors. It is shown that the variation relationship between the coefficient and the effective pressure can be described by a power function. Such a coefficient can evaluate well the changing trend of the permeability of coal samples related to the effective pressure. The between coal sample permeability and the effective pressure is deduced based on the coefficient of sensitiveness.

Abstract:To explore the safety of dam in future operation, we study the stability of Xiaodae tailing dam, Sichuan Province, P. R. China, via model testing and numerical simulation according to preliminary dam design information. The results show that the deposited beach length initially is shorter and the depth of the saturation line in a tailing dam is relative shallow. The length of deposited beach is relatively long in the middle and later periods, and the saturation line maintains a relatively stable position. The numerical simulation shows that horizontal dam displacement is 0.68 m and the greatest vertical displacement is 3.44 m at the dam vertices when the dam reaches the designed elevation. Meanwhile, the dam possesses normal stability. The largest shear stress in flooding exceeds that of normal conditions and the dam saturation line is higher. Unless measures are taken, these conditions will influence dam security.

Abstract:We explore the destruction of outburst prevention air doors by coal and gas outbursts using numerical simulation. The reflective overpressure when an outburst acts on doors is elucidated, and its formula is obtained. The destruction of outburst prevention wind doors by coal and gas outburst are simulated using ANSYS software based on data of wind door pressure obtained by similarity simulation experiment. The simulation results show that the weakest place of gate posts is where the wind tube is. Simulation results also show the first shock wave pressure that acts on an outburst prevention wind door is not the maximum one. Due to the effect of reflected overpressure, the outburst prevention wind door pressure will reach the maximum in several milliseconds. This finding is similar to the experiment result.

Abstract:We study methane backward flow in the laneways at various wind velocities and angles based on computational fluid dynamics theory; analyze the backward flow area length, the concentration distribution and the methane roof layer thickness. The results show that the methane roof layer would move against the airflow in a declensional ventilated airway if the downward air velocity is not large enough. The faster the airflow speed, the smaller the methane backward flow area becomes, and the methane roof layer becomes thicker and shorter. In a declensional ventilated airway, the methane/air mixing capacity increases with the increase of the inclination of the airway, and the thickness of methane roof layer decreases with the increase of the inclination of the airway.

Abstract:The singular value decomposition (SVD)based orthogonal frequency division multiplexing (OFDM) channel estimation can guarantee channel estimation performance, while reducing computation. A simplified implementation method for SVD of a Hermitian matrix is proposed which transforms a Hermitian matrix SVD to a real symmetry matrix SVD to achieve highspeed operation. The systolic array structure is improved based on the SVD characteristics for symmetry matrix to conserve system resources. The field programmable gate array (FPGA) implementation program of high rank real symmetry matrix singualar value decomposition(SVD)is designed. The simulation results demonstrate that the designed program is feasible for OFDM channel estimation.

Abstract:The design of compact and multiband antenna is increasingly important as multimode and multiband small communication equipment develops. A novel ultrawideband, cupshaped monopole antenna with three holes is presented with the virtues of the ring microstrip and monopole antennae. Experimental results show that the antenna bandwidth is greatly improved when compared to a traditional monopole antenn , The antenna offers an ultrabroadband performance in the frequency band 925.0 GHz, covering the L to K bands, and possesses a VSWR under 0∶1. With this very wide bandwidth, the antenna is attractive in multiband wireless communication.

Abstract:Based on the basic generation model for the independent component analysis (ICA) and the fixedpoint FastICA algorithm using negentropy, three observed signals containing maternal electrocardiogram (MECG) and fetal electrocardiogram (FECG) components obtained from abdomen of a pregnant woman are successfully separated by using the FastICA algorithm with progressive orthogonalization, and the FECG is extracted. By invoking the wavelet denoising program in Matlab, the extracted FECG is decomposed to 8 levels with db2 wavelet to obtain the default soft threshold for denoising. The results show that the FastICA algorithm with progressive orthogonalization performed fast convergence. The three source components were extracted with only seven, three, and two iterations, respectively. The noise in the extracted FECG can be eliminated using wavelet denoising.

Abstract:An adaptive transmission power allocation (TPA) algorithm is presented for the turbobell labs layerecl spacetime(TurboBLAST) system. This algorithm aims to find the proper power allocation parameters with which the overall bit error rate (BER) can be minimized. At the transmitter, the TPA algorithm is used to allocate proper power to every antenna under the restriction of total transmission power. At the receiver, a modified iterative soft interference cancellation scheme is used to detect received signals to reduce BER further. Simulation results show that the BER of the proposed scheme can be decreased significantly compared with that of equal power allocation.

Abstract:To describe the motion state of multijointlinkage in series transformation, a method to solve the motion state and attitude position by measuring the magnetic induction density and acceleration is studied. The angle calculation is performed by employing the direction cosine transformation between the geographical coordinate and the basic coordinates of the magnetic and gravitational fields of the earth. The mode of the attitude angle, denoted by the magnetic induction density and acceleration, is obtained. The angle transformation during the coordination transformation is analyzed. The relationship between attitude angle of the linkage and the angle of the linkage in the series transformation is deduced. An example is used to verify the model. This model can solve the transformation problem between attitude angle and real angle, which is the same as the motion expression of the body.

Abstract:To address the problem of planning complete coverage paths for cleaning robots that have the greatest coverage rates and the lowest recover rates, we propose a back propagation (BP) neural network algorithm for local path planning based on plowing global path planning. We also propose an improved BP neural network algorithm based on the deepfirst coverage algorithm for the issue of cleaning dead areas. Simulation results show that the proposed algorithm can plan complete paths for the robots.

Abstract:It is necessary to predict and control deflection and stress in continuous beam bridge construction. SCGMmv (1, h) is a multifactor forecasting model for a time series based on the mean values. For a specific project, by using the association between deflection and stress, the SCGMmv (1, h) forecasting model is employed to obtain forecast values of deflection and stress, which are compared with the forecast values of the GM (1,1) prediction model. The results show that the SCGMmv (1, h) multifactor forecasting model is feasible and effective for deflection and stress prediction in continuous beam bridge construction.

Abstract:To counter deficient medical knowledge sharing and the lowefficiency cooperative diagnosis between doctors, the knowledge flow from knowledge management (KM), knowledge acquisition and knowledge supply are established as the core infostructure of a hospital KM model. This is done by combining heavy idea exchange, frequent updating, and intensive use of the medical knowledge. Three important knowledge flow(KF) operations (knowledge refreshing, knowledge migration and knowledge expansion) are proposed. By comparing hospital information management with hospital KM, a hospital KM method based on knowledge flow is constructed. The method emphasizes tracking, monitoring and controlling hospitalwide comprehensive process of medical knowledge. A specific clinical diagnosis instance is given for detailed healthcare knowledge flow analysis. 