Volume 36,Issue 8,2013 Table of Contents

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  • 1  CFD simulation analysis and experimental verification on heat dissipation system of Ni-MH battery packs in HEV
    QIN Datong MA Zhaoqiang HU Minghui CHEN Shujiang
    2013, 36(8):1-8. DOI: 10.11835/j.issn.1000-582X.2013.08.001
    [Abstract](1692) [HTML](445) [PDF 9.62 M](1814)
    Abstract:
    The flow field of the heat dissipation system of nickel-hydrogen(Ni-MH) battery package used in hybrid electric vehicle(HEV) is simulated with Fluent software. The steady-state simulation analysis on the temperature field of the Ni-MH battery package is carried out based on the air flux in the battery packages. The sensors arrangement scheme for the temperature field measurement experiment is decided based on the temperature field simulation result. The experiment of the temperature field measurement is performed under the condition of the driving cycle of the HEV. Then the transient temperature field of the battery package is analyzed based on the unit volume thermal power,which is calculated from the current data got from the experiment. The result shows that the simulation results mach well with the experimental data,and the heat dissipation system of the battery package function well for heat dissipation,which satisfies the demand of the HEV on the battery package.
    2  Calculation and analysis of strength for elliptical bevel gear
    LIN Chao NIE Ling ZENG Qinglong GONG Hai
    2013, 36(8):9-15. DOI: 10.11835/j.issn.1000-582X.2013.08.002
    [Abstract](2096) [HTML](615) [PDF 7.68 M](1328)
    Abstract:
    Based on the plane equivalent pitch curve of elliptical bevel gear,the pressure angle in the transmission is acquired with differential geometry and gear meshing theories. The force analysis in the meshing process is performed and the formulas of tangential force and normal force on the gear teeth are derived. A method to calculate elliptical bevel gear’s strength in a successive way is established and the regulation of the tooth surface contacting stress and the root bending stress changing with the angle of driving gear is discussed. Then the position of the weakest tooth is determined and the influence of basic parameters including module,number of teeth and eccentricity ratio on contacting stress and bending stress is analysed. Comparing with traditional calculation for spur bevel gear,the exactness of this successive strength calculation method is verified.
    3  Using STFT-Wigner transform to suppress the cross terms in Wiger-Ville distribution
    WANG Jian LI Jintong LU Hualing YIN Aijun
    2013, 36(8):16-18. DOI: 10.11835/j.issn.1000-582X.2013.08.003
    [Abstract](1883) [HTML](357) [PDF 5.30 M](1432)
    Abstract:
    There is a serious crossing-term problem when Wigner-Ville distribution(WVD) is used to analyze multi-component non-stationary signals. While,using Gabor-Wigner transform(GWT) can avoid the crossing-term problem and maintain the clarity as good as WVD. But as the component frequency of multi-component signals interfere each other,GWT can’t get clear-cut results. A modified STFT-Wigner is proposed to suppress the cross terms in WVD effectively and maintain the clarity. This method is proved to be practical through analyzing simulation signals and experiment signals.
    4  Control strategy for starting up of pure electric vehicle
    HU Jianjun DU Rui JI Yi
    2013, 36(8):19-25. DOI: 10.11835/j.issn.1000-582X.2013.08.004
    [Abstract](2201) [HTML](427) [PDF 8.07 M](1676)
    Abstract:
    In order to solve the problem of large jerk and easy slipping down on the ramp in the starting process of the pure electric vehicle,starting up control strategy of pure electric vehicles is established on the basis of meeting the driver’s driving intentions. The starting process of pure electric vehicle is divided into mode without throttle opening and mode with throttle opening. And corresponding control strategies for the two modes are formulated respectively. The starting performance of pure electric vehicle adopting the control strategy is analyzed. The results show that the strategy satisfies the requirements of smoothness and safety well in the starting process of the pure electric vehicle.
    5  FxLMS algorithm’s realization and verification by hardware in the loop simulation
    ZHANG Feng LI Yinong DING Qingzhong
    2013, 36(8):26-32. DOI: 10.11835/j.issn.1000-582X.2013.08.005
    [Abstract](2187) [HTML](593) [PDF 10.36 M](2459)
    Abstract:
    Active vibration control uses an active anti-force from secondary path to suppress or attenuate vibration and noises. One of the wildly-used control algorithms is filtered-x least mean square(FxLMS) adaptive algorithm. Based on structure of FxLMS algorithm,Level-2 S function is used to build a new FxLMS blocks in Matlab/Simulink,which is applied to offline vibration active control system simulation. On the condition of convergence,performance analysis is carried out by adjusting interior parameters to test the control algorithm block. Finally,the custom FxLMS block is downloaded to dSPACE as controller,and used in hardware-in-the-loop simulation of active vibration control on a gear transmission system. Results verified the custom FxLMS block’s feasibility built by Level-2 S function and control algorithm’s efficiency.
    6  The water quality comprehensive evaluation and cluster analysis on drinking source water in Chongqing
    XIANG Ping ZHANG Zhi ZHANG Nan
    2013, 36(8):33-39. DOI: 10.11835/j.issn.1000-582X.2013.08.006
    [Abstract](1733) [HTML](456) [PDF 7.67 M](1339)
    Abstract:
    Recent researches on the Yangtze River and the Jialing River water in Chongqing section of the Three Gorges Reservoir indicate that the pH value is relatively high and the CODMnconcentration is more than 4.5 mg/L in most of the time. Especially the proportion of dissolved molecule organic is high, as well as the high turbidity during the summer flood period. And the organic contamination is relatively serious. The fuzzy weighted water quality coefficient and hierarchical cluster analysis methods are applied to evaluate and sort the characteristic qualities of two-river water sources. During the research period, the results show that the Yangtze River water source quality is characterized by high turbidity and polluted of summer stage, middle temperature and micro-polluted of spring-autumn stage and low temperature and micro-polluted of winter stage. The Jialing River water source quality is characterized by low turbidity stage, high alga-polluted of early spring stage and high temperature and polluted of winter stage. Due to the various water qualities of two-river water sources at different periods, it is hard to meet the requirement of Standards for Drinking Water Quality (GB 5749-2006) by using traditional water treatment technologies. So the research on enhanced treatment is necessary.
    7  Research on capacitated vehicle routing problem with cloud adaptive genetic algorithm
    JIAN Jie WANG Xu GE Xianlong
    2013, 36(8):40-46. DOI: 10.11835/j.issn.1000-582X.2013.08.007
    [Abstract](1803) [HTML](582) [PDF 6.46 M](1716)
    Abstract:
    Aiming at traffic volume and vehicle utilization,which are closely related to the cost of vehicle traffic,a vehicle scheduling model with the minimum fuel cost and fixed cost is established. According to the requirement of real-time and complicacy of the vehicle scheduling,a cloud adaptive genetic algorithm is proposed by combining cloud model theory with genetic algorithm. The way of the fixed set crossover and mutation probability in the standard genetic algorithm is improved by using the randomness and bias stability of the cloud droplet cloud model. Defects of slow search and easy precocious of the standard genetic algorithm is overcome. The convergence and robustness of the algorithm was improved by crossover and mutation that was designed based on maximum retention mechanism. Finally,an example authenticated the effectiveness of the model and algorithm.
    8  Remaining useful life prediction of the lithium-ion battery using particle filtering
    MIAO Qiang CUI Hengjuan XIE Lei ZHOU Xue
    2013, 36(8):47-52. DOI: 10.11835/j.issn.1000-582X.2013.08.008
    [Abstract](1976) [HTML](533) [PDF 7.35 M](2743)
    Abstract:
    A particle filtering algorithm for predicting the remaining useful life of the lithium-ion battery is presented. First,the concepts and steps of the proposed method are introduced. Then,the particle filtering based method is used to predict the remaining useful life of the lithium-ion battery with experimental data. Comparison study with the extended Kalman filtering based prediction technique is conducted to evaluate the performance of the particle filtering algorithm. The results show that the particle filtering algorithm is more accurate and can predict the actual failure time with an error less than 5%.
    9  Development of discone antenna for noncontact partial discharge detection
    YAO Chenguo CHEN Pan ZHOU Dianbo XING Lin
    2013, 36(8):53-60. DOI: 10.11835/j.issn.1000-582X.2013.08.009
    [Abstract](1785) [HTML](293) [PDF 9.73 M](1689)
    Abstract:
    To realize the noncontact detection of partial discharge of electrical equipment within some range,a wideband,good gain and horizontal plane omnidirectional ultra-high frequency antenna is researched,and it is used as detecting sensor of partial discharge(PD) signals. Characteristic radiation and characteristic impedance of discone antenna are analyzed,and it is found that it is dominant to design the dicone antenna as UHF signal detecting antenna. Then the structure of the antenna is optimized via calculate simulation. The band of the discone antenna is from 200 MHz to above 2 GHz and its average gain is above 4 dB. It is made via discrete method according to the analysis and simulation result,satisfying the design demand. The discone antenna shows good performance to detect analog discharge signals and PD signals in substation from far away. Fixed and mounted PD monitoring system can be developed based on this antenna,and the system can monitor PD of electrical equipment within substation without contacting equipment.
    10  Analysis on steady-state mathematical models and operating characteristics of brushless doubly-fed machine
    HAN Li LUO Jie WANG Hua PAN Hongguang
    2013, 36(8):61-67. DOI: 10.11835/j.issn.1000-582X.2013.08.010
    [Abstract](1879) [HTML](315) [PDF 9.42 M](1078)
    Abstract:
    To further study the steady-state characteristics of brushless doubly-fed machine(BDFM) with squirrel-rotor,the basic equations are given according to the coupling circuits of BDFM. And then,the mathematical models of BDFM current,active power,reactive power,electromagnetic torque and power factor are analyzed and derived respectively. Furthermore,the characteristics of torque-angle,torque-frequency,power-angle,reactive power,power factor and V-shaped curve of BDFM are obtained respectively by MATLAB simulation of a prototype. The energy conversion of BDFM is analyzed by the proposed mathematical models at the same time. The results show that all the steady-state characteristics of BDFM can be expressed as the functions of the control windings voltage,frequency and the power angle. The proposed model simplifies the analysis of the steady-state characteristics of BDFM and provides a theoretical foundation for the further study on operating stability and control strategy of BDFM.
    11  Photoacoustic spectroscopy applied to the detection of SF6decomposition components under partial discharge
    TAN Zhihong TANG Ju SUN Caixin FAN Min ZHU Liming
    2013, 36(8):68-75. DOI: 10.11835/j.issn.1000-582X.2013.08.011
    [Abstract](1697) [HTML](426) [PDF 7.82 M](1154)
    Abstract:
    The traditional detection methods of SF6 decomposition components under partial discharge have some shortages,including consuming much detected gas,long detecting time,and unsuitable for on-line monitoring. While,photoacoustic spectroscopy has some advantages,including high sensitivity on detecting gas,and without consuming detected gas,etc. According to these reasons,the detection technology used in SF6 decomposition components under partial discharge is studied,and the feature spectrum of SO2,CO2 and CF4by SF6 decomposing is given. Through the photoacoustic spectroscopy device,the relation lines between photoacoustic spectroscopy(PAS) signal and concentration of gas components are obtained. The minimum detection limits of SO2,CO2 and CF4are about 3.8×10 -6,3.1×10 -6 and 4.7×10 -6 respectively. A method of RBF neural network is set up to reduce the crossover response of PAS signals of SO2,CO2 and CF4 mixed gas. It makes the average examination error of three gases reduce to 5.6%,1.6% and 3.3% respectively. Its reliability is checked by comparative testing of gas ehromatography and detector tube. The results indicate that the RBF neural network is useful in improving detection precision and provides a kind of technology to crossover response problem.
    12  Improved control strategy of direct-driven permanent magnet synchronous generator for wind turbine under unbalanced grid faults
    ZHUANG Kai LIAO Yong LIU Ren YAO Jun LI Hui
    2013, 36(8):76-84. DOI: 10.11835/j.issn.1000-582X.2013.08.012
    [Abstract](2345) [HTML](3292) [PDF 13.26 M](8776)
    Abstract:
    An improved unbalanced grid fault ride-through control strategy is proposed to meet the low voltage ride through(LVRT) requirements based on the analysis of power characteristics of a full rated converter for direct-driven permanent magnet synchronous generator(PMSG). According to the power characteristics,the relationship among dc-link capacitor voltage,power absorbed by interface reactors and grid-side power output is studied. The information of grid voltage drops is introduced into generator-side converter control to achieve coordinated control of grid-side converter and generator-side converter. The soft control strategy on dc-link capacitor voltage is adopted to suppress double-frequency active power ripple at the expense of a certain voltage fluctuations which is still within the safety range. The simulation results demonstrate that the proposed control strategy can enhance direct-driven PMSG’s unbalanced grid faults ride-through capability.
    13  Feed-rate-controlled method of iterative algorithm for curve interpolation
    DENG Changqi LIAO Hui
    2013, 36(8):85-90. DOI: 10.11835/j.issn.1000-582X.2013.08.013
    [Abstract](1544) [HTML](664) [PDF 6.09 M](1612)
    Abstract:
    In order to maintain a high machining accuracy and a constant speed feed-rate in CNC machining and improve the machining capability of CNC in handing complex part,the complicated interpolation algorithm needs to be used in CNC interpolation,which is time-consuming for large amount of computation,thus the machining speed is influenced. To solve this problem,based on the principle of parametric curve paths CNC interpolating,it is pointed out that Taylor series and iterative algorithm,given curve,using the chord length and the interpolation point,accurately calculate the next interpolation points. In the number of iterations and iterative error are less than the set value when the end of the iteration,next interpolation points can be calculated,and keep the current point and speed,otherwise continue iterative algorithm until they meet the requirements,feed-rate-controlled method based on iterative algorithm for curve real-time interpolation has also been given. The simulation results demonstrate that the proposed algorithm can satisfy the machining of a variety of different parametric curves. Compared with the conventional interpolation algorithm,it features are high university for machining,small computational a mount small feed-rate error and high computational accuracy,thereby greatly shorting the processing efficiency.
    14  Improvement of vehicle air-conditioning duct and analysis of its impact on occupant thermal comfort
    GU Zhengqi SHEN Hongli YANG Zhendong YIN Yuqi
    2013, 36(8):91-96. DOI: 10.11835/j.issn.1000-582X.2013.08.014
    [Abstract](1730) [HTML](531) [PDF 7.67 M](1885)
    Abstract:
    A numerical simulation on the air flow in vehicle air-conditioning duct is conducted by applying computational fluid dynamics(CFD)code Fluent and its result is compared to test result within a very small difference. Besides, the result shows that the distribution of air flow is so uneven that the thermal comfort of driver is rather poor. To improve it, the air-conditioning duct system is optimized by response surface methodology which took three structural dimensions of the deflector attached to it as design variables and considered the airflow ratio of the driver side and the overall airflow as optimized purposes, and then the thermal comfort analysis of the driver was performed to the improved air-conditioning system. As a result, the airflow ratio of the driver side is improved to 51.3% from 44.9% due to the optimized air-conditioning duct, as well as that the thermal comfort of the driver is obviously improved.
    15  Application of FEM strength reduction method to geotechnical engineering with the consideration of tension and shear failures
    JIN Xiaoguang CHEN Lihua ZHANG Yongxing
    2013, 36(8):97-104. DOI: 10.11835/j.issn.1000-582X.2013.08.015
    [Abstract](1831) [HTML](327) [PDF 8.73 M](1675)
    Abstract:
    The failure characteristic of geomatertials in different stress states is analyzed, and it is found that the stability of geotechnical structure depends on not only shear strength index c and tanφ, but also tensile strength index T. The overvalued of tensile strength of materials could lead to non-conservative results in the primary strength reduction method. Therefore, the FEM strength reduction method should take identical reduction of both tensile strength index and shear strength index into account. In other word, tension and shear strength reduction method (TSSR) in the process of strength reduction should be adopted. The necessity and correctness of TSSR is validated by stimulating four typical example models, i.e. the general slope, the stalactite, the tunnel and the steep slope. Studies show that the modified strength reduction method has universal applicability in geotechnical engineering.
    16  A record-based simulation of spatially correlation ground motion
    LI Yingmin WU Zheqian CHEN Huiguo
    2013, 36(8):105-110. DOI: 10.11835/j.issn.1000-582X.2013.08.016
    [Abstract](1690) [HTML](595) [PDF 8.62 M](1109)
    Abstract:
    A record based approach has been developed for the simulation of spatially correlated ground motion. This procedure uses autoregressive model to establish a power spectrum, and uses the multivariate linear prediction to simulate the parameter of unknown position. The random factor of earthquake is relected by Gaussian distribution random number, and the known records are subdivided into a sequence of time windows to account for its temporal variation. Compare of the simulated record and the true record show that this procedure is accurate and reasonable, and it is applicable for the design of discretely supported systems.
    17  Post-buckling and mode jumping analysis of angle-ply composite laminates
    ZHONG Yifeng CHEN Lei YU Wenbin ZHANG Liangliang
    2013, 36(8):111-117. DOI: 10.11835/j.issn.1000-582X.2013.08.017
    [Abstract](1821) [HTML](283) [PDF 6.85 M](1344)
    Abstract:
    The governing partial differential equations (PDEs) are deduced from the asymptotically correct, geometrically nonlinear theory to research the bucking and mode jumping behavior of biaxially antisymmetric angle-ply composite laminates. The PDEs are transformed into a system of nonlinear ordinary differential equations (ODEs) by using the generalized Galerkin method. Then, the post-buckling behavior is analyzed by using the solution extension software. At last, the paths of buckling mode jumping and critical loads for the composite laminates under the in-plane boundary condition of straight edge are determined. An example of 4-layer composite laminates shows that the numerical results in the primary post-buckling region from the present method agree with the finite element analysis (FEA); while the FEA may lose its convergence when solution comes close to the secondary bifurcation point, the analytic method has the capability to explore deeply into the post-secondary bucking realm and capture the mode jumping phenomenon.
    18  A static equilibrium method for tension identification of in-service cable
    WANG Long WU Bo GAO Junyue WANG Fan
    2013, 36(8):118-126. DOI: 10.11835/j.issn.1000-582X.2013.08.018
    [Abstract](1525) [HTML](408) [PDF 10.60 M](1239)
    Abstract:
    To identify the tension of in-service cable expediently and accurately, a cable tension identification method based on static testing measures is proposed by taking cable stress stiffening effect and principle of static equilibrium into account. According to the analysis on the process of cable tension identification and the key technique, a new compound clamp type with the soft metal lining is proposed. The rule of the contact distortion evolvement between the clamp and the cable is analyzed by dynamic nonlinear explicit analysis method, and the law of the friction change following the clamping force is studied. Thus, the reasonability and feasibility of this method is theoretically illuminated. The identified tension only depends on the displacement of load application point and the load force. The proposed method avoids the drawback of normal cable measuring methods where the measuring accuracy is greatly affected by cable boundary conditions and values of material parameters. The tension measured in the method is only related to the displacement of force point and the value of force. Therefore, it provides a new idea for cable tension identification of flexible cable.
    19  Study on mechanical behaviors of interface with cemented soil slurry between gravel and concrete by simple shear tests
    PENG Kai ZHU Jungao FENG Shurong CAI Changguang ZHU Sheng
    2013, 36(8):127-135. DOI: 10.11835/j.issn.1000-582X.2013.08.019
    [Abstract](1820) [HTML](615) [PDF 12.71 M](1397)
    Abstract:
    The mechanical behaviors of the interface between coarse-grained soil and concrete are investigated by simple shear tests under conditions of cemented soil slurry (clay mixed with cement grout). The results show that the relation curve between shear stress and shear strain appears stress-strain softening and shear dilatation is significant. The point of peak strength and the position when the shear dilatation occurs are related to normal stress. In addition, shear dilatation occurs before the shear stress reaches peak value. In shear failure state, with the same height, the shear displacement increases as the normal stress increases. While with the same normal stress and at the same height, the shear displacement increases as the concrete content increases. A particle flow model of simple shear test between interface between coarse-grained soil and concrete is constructed by PFC (particle flow code). The disturbed height of the sample and the main influence factors are determined by analyzing the laws of particle motion at different heights inside the sample. The PFC results show disturbed height of the sample is related to maximum particle diameter of the soil, normal stress and roughness of the interface (with or without slurry) etc. In terms of the coarse-grained soil, the shear displacement is significant in the area which is close to the interface and about 3-4 times of the maximum particle diameter, and informed the obvious shear band. Further, the thickness of the interface can be regarded as the value.
    20  A forward algorithm for prestressed construction process of large-span suspendome based on the equivalent pre-tension
    WANG Yongquan GUO Zhengxing LUO Bin GUO Wei
    2013, 36(8):136-144. DOI: 10.11835/j.issn.1000-582X.2013.08.020
    [Abstract](1816) [HTML](547) [PDF 9.84 M](1252)
    Abstract:
    To accurately simulate prestressed construction process of large-span suspendome, the initial state of construction process according to practical construction sequence is established, and the construction mechanical analysis for prestressed construction process is especially studied. Features of prestressed construction process of large-span suspendome are summarized, and the insufficiencies of the application of state variable superposition method, back analysis method, birth and death element method are analyzed. Combined with nonlinear finite element analysis method, forward algorithm for prestressed construction process based on the equivalent pre-tension is proposed, and the specific application method and procedure are given. Changzhou stadium steel roof engineering is taken as an example to verify the practicability and applicability of forward algorithm for prestressed construction process. The conclusion is that, using forward algorithm for prestressed construction process based on the equivalent pre-tension, the structure state of each construction phase can be accurately tracked, and the nonlinear contact of strut and rigid framework, interactive impact of cable force, conversion of temporary structure system, and structural geometric nonlinearity can be comprehensively considered.
    21  Design of a miniaturized wind energy harvester based on a fluttering flexible beam
    ZHAO Xingqiang WEN Zhiyu
    2013, 36(8):145-150. DOI: 10.11835/j.issn.1000-582X.2013.08.021
    [Abstract](1697) [HTML](298) [PDF 6.31 M](1656)
    Abstract:
    A fluttering-based miniaturized wind energy harvester is presented. The harvester is comprised of a lead zirconate titanate(PZT) piezoelectric beam and a flexible beam. The flexible beam vibrates the PZT beam when flutter motion triggers. The flexible beam flutter motion is investigated in a small wind tunnel. It’s found that flutter occurs between of cut-in and cut-out critical wind speeds. Effects of the flexible beam length and width on the device characteristics are investigated. It’s found that with the increase of the length, the critical wind speed, fluttering frequency, output voltage and power of the device decrease. While with the increase of the width, the critical fluttering speed is nearly unchanged, and the fluttering frequency, output voltage and power of the device all increase. The minimum critical wind speed of the harvester is 6.4 m/s and the maximum power is 1.30 mW. The results show that the flexible beam structure can reduce the critical wind speed and increase the output power of the PZT beam. The feasibility of the wind-induced vibration energy harvester is confirmed.
    22  Finite element modeling of current stimulating response on the nerve axon
    REN Yong CHEN Yu CHEN Jing KANG Jianyi ZHAO Hui
    2013, 36(8):151-155. DOI: 10.11835/j.issn.1000-582X.2013.08.022
    [Abstract](2093) [HTML](528) [PDF 6.27 M](1781)
    Abstract:
    To investigate the characteristics of microphysiological electrical conduction on nerve cell axon, numerical simulation for the dynamic responses of neuronal axon to electrical stimulation is conducted on a three-dimensional (3D) finite element (FE) model. A 3D geometrical model for a segment of a hippocampal neuron axon is developed and assigned biophysical parameters, then the stimulation pulses of various amplitude and duration are imparted on the FE model of neuronal axon. The combination of Hodgkin-Huxley equations and Maxwell equations are performed to get action potential curve and 3D distribution of electric potential. The simulating results show that the resting potential of nerve axon is -65 mV and no action potential occurred under the stimuli of 2 ms duration and 0.01 A/m 2 current intensity, whereas the stimuli of (2 ms, 0.2 A/m 2), (20 ms, 0.01 A/m 2) and (20 ms, 0.2 A/m 2) induced action potentials, and the time arrived at the peak value are 0.012 s, 0.017 s and 0.012 s, respectively. The range of action potential is 100 mV and duration is 2 ms. The simulation results agree well with that of the experiment, which indicates that both the FE model of neuronal axon and the simulation analysis method are reliable and may contribute to further study on neural electrophysiology.
    23  Fuzzy webpage text classification algorithm combined with improved NMF
    JIA Zhaohong LI Longshu ZHU Jianjian
    2013, 36(8):156-162. DOI: 10.11835/j.issn.1000-582X.2013.08.023
    [Abstract](1572) [HTML](318) [PDF 6.33 M](1179)
    Abstract:
    An item-document weight matrix representing the web pages could be generated by constructing the vector space model. Since the efficiency of direct classification through the high-dimensional matrix is relatively low, a fuzzy webpage text classification algorithm combined with improved nonnegative matrix factorization (NMF) is presented. Firstly, the original high-dimensional data are mapped into the low-dimensional semantic space via an iterative normalized compression NMF(NCMF) to reduce the complexity of the problem. Secondly, in order to solve the problem of categorizing ambiguous words by using deterministic matrices, fuzzy logic is incorporated into the classification model, where the fuzzy categorization set of the document is constructed with the fuzzy membership degree between features and categories. Comparative experiment results demonstrate the proposed classification algorithm possesses higher accuracy and better time performance.

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