2003 Vol.21

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Automatic Recognition Algorithm of the Upper Sideband and the Lower Sideband SSB Signals by Using the Adaptive Threshold FANG Xiao-qing, JI Yong, XU Pei-xia Journal of Applied Sciences    2003, 21 (1): 1-4.   Abstract （403）      PDF（pc） （318KB）（101）       Knowledge map    Save Based on the statistical characterisitic of speech spectrum, a new algorithm which can distinguish LSB or USB cases of speech from SSB signals without any prior information is presented here. It is simple and very suitable for DSP's real-time implementation, and the adaptive threshold increases the algorithm's robustness. The simulation results show that this algorithm gives good performance even under the conditions of low SNR values. Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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An Investigation of the Modeling for a Parallel Directional Coupler Based on the 3D-GM-BPM XIAO Jin-biao, SUN Xiao-han, CAI Chun, ZHANG Xi-fei, ZHUJian-bin, ZHANG Ming-de, DING Dong Journal of Applied Sciences    2003, 21 (1): 5-8.   Abstract （368）      PDF（pc） （313KB）（72）       Knowledge map    Save A three-dimensional beam propagation method based on the Galerkin method (3D-GM-BPM) is proposed for directly modeling a parallel directional coupler based on optical rib waveguides. The computational efficiency is raised due to the small matrix derived from this method, which is reduced to solver a first-order normal differential equation system. A tangent-type function is applied to map the infinite region into closed region. As a result, the artificial boundary condition is eliminated. Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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A Novel Low Complexity Receiver in the Low Spreading Factor for the CDMA System ZENG Rong, ZHAO Chun-ming Journal of Applied Sciences    2003, 21 (1): 9-12.   Abstract （311）      PDF（pc） （318KB）（101）       Knowledge map    Save In the CDMA system, the inter-path interference (IPI) becomes very serious when the spreading factor is low. In order to decrease IPI, a low complexity receiver structure in the low spreading factor for the CDMA system which combines the conventional Rake with chip equalizer is proposed. Computer simulation shows that the Equalizer-Rake receiver performs better than Rake and chip equalizer with equal complexity. Related Articles | Metrics | Comments（0）

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Performance of Nonuniform 16-DAPSK Modu-lation with Punctured Convolutional Coding on Radio Broadcasting Channels SAYHOOD Khalid Hassan, WU Le-nan Journal of Applied Sciences    2003, 21 (1): 13-19.   Abstract （376）      PDF（pc） （483KB）（75）       Knowledge map    Save Simple closed-form expressions for the probability of error for nonuniform 16-differential amplitude phase-shift-key (DAPSK) signaling over an additive white Gaussian noise (AWGN) and Rayleigh fading channels are presented. The performance of nonuniform 16-DAPSK with punctured convolutional coding is presented. The results show that the coding can be used with nonuniform 16-DAPSK modulation to transmit additional message in radio broadcasting systems with little degradation to the basic message. Related Articles | Metrics | Comments（0） Cited: Baidu(3)

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The New Reliability Design Theory of Multiple Failure Modes for Machine Elements XU Hong-wei, YU Tian-xiang, ZHANG Xuan-sheng, ZHANG Zu-ming Journal of Applied Sciences    2003, 21 (1): 20-24.   Abstract （356）      PDF（pc） （391KB）（93）       Knowledge map    Save The new reliability design theory of multiple failure modes for machine elements is presented. The reliability design computing method of multiple failure modes for machine elements is developed, and the Ditlevsen theory is used to prove the new theory. Finally, an example is given to show how the new theory is used. Related Articles | Metrics | Comments（0） Cited: Baidu(5)

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The Grey Optimum Model for the Test of the Fineness of Ramie Fiber and Its Error Analysis LI Xiao-feng, LUO You-xin Journal of Applied Sciences    2003, 21 (1): 25-29.   Abstract （313）      PDF（pc） （382KB）（84）       Knowledge map    Save The grey modeling method has been developed according to the theory of the grey system and is used for correlation analysis of experimental data. Compared with the method of data regression, the grey model analysis (GMA) enjoys an obvious advantage. It can enhance the reliability of prediction in particular, in the testing of samples of small size. In this paper, the grey GM (1,2) model and grey optimum GM* (1,2) model for the testing and analysis of the fineness of ramie fiber are described. Correlation analysis is then performed to predict the relationship between the data Tex (sample Y) and the data projection breadth (sample X). The error is evaluated and proves acceptable. The model for testing the fineness of ramie fiber established on it provides a concise and scientific method for technical control of production, quality inspection and supervision. Related Articles | Metrics | Comments（0） Cited: Baidu(4)

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A Genetic Algorithm for QoS Multicast Routing with Imprecise State Information CHEN Ping, DONG Tian-lin Journal of Applied Sciences    2003, 21 (1): 30-35.   Abstract （298）      PDF（pc） （540KB）（74）       Knowledge map    Save Most of the known QoS multicast routing algorithms are based on accurate network state information available, however, we cannot obtain accurate information in fact. So the problem is how to construct multicast routing trees with QoS requirements satisfied when the information available for making such routing decisions is inaccurate. This paper presents a new heuristic genetic algorithm ISIMR-GA for solving the problem. Based on PC-ISI algorithm which is a kind of unicast routing algorithm used in inaccurate information networks environment. the ISIMR-GA can improve the searching ability and quicken the convergent speed by selecting initial population and using a series of heuristic genetic operations. Moreover, the simulation results demonstrate that the algorithm performs very well. Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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Recognition of the Scanning Style of the Radar Antenna Using Immune Neural Networks TANG Bin, HU Guang-rui Journal of Applied Sciences    2003, 21 (1): 36-38.   Abstract （285）      PDF（pc） （275KB）（100）       Knowledge map    Save The scanning style of the radar antenna varies with the working state. The correct recognition of radar scanning style is important in deciding its threatening degree to our side. It is also an important means to recognize the types and working styles of radar. We uses the radial basis function (RBF) network based on immune evolutionary algorithm to recognize the scanning style of the radar antenna. Computer simulation shows that for simple radar scanning styles, the recognition rate of immune RBF network has reached 99. 13% when SNR is 4dB. The training period of the network has only 99 steps, which proves its excellent performance. Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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A Robust Method of Real-Time Motion Estimation in Model-Based Image Coding LI Zhong-ke, YANG Xiao-hui, WU Le-nan Journal of Applied Sciences    2003, 21 (1): 39-43.   Abstract （279）      PDF（pc） （603KB）（85）       Knowledge map    Save In this paper, the nature of the PLS algorithm is analyzed. To overcome its disadvantages, a modified PLS algorithm is proposed. Experimental results are presented to provide synthetic data and real image sequences. Compared with PLS and EKF algorithm, the modified algorithm can estimate motion more accurately in real-time. Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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Joint Estimation of PN Code Delay and Multipath Using the Unscented Filter XUE Wen-hu, CAN Zhong-min Journal of Applied Sciences    2003, 21 (1): 44-48.   Abstract （300）      PDF（pc） （399KB）（80）       Knowledge map    Save In this paper the problem of joint estimation of PN code delay and multipath channel coefficients is considered. We present an estimator based on the unscented filter (UF) for the joint estimation of delay and multipath, and obtain the simulation results of the estimator. Next the mean square error (MSE) of the UF estimator is compared with both the MSE provided by EKF and the Cramer-Rao lower bound. The results show that the UF performs better than the EKF in multipath channels. Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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A New Scheme for Adjusting the Estimated Average Length of Channel MA Zhang-yong, ZHAO Chun-ming, YOU Xiao-hu Journal of Applied Sciences    2003, 21 (1): 49-52.   Abstract （353）      PDF（pc） （326KB）（109）       Knowledge map    Save The author proposes that the channel coefficient of the effective arriving path can be estimated with the Rake coherent receiver. By calculating the level cross rate (LCR) of the envelope, the Doppler-shift is estimated. The observation length is then adjusted dynamically with the help of the connection between the Doppler-shift and the optimal observation length, enabling the whole receiver to obtain better performance in variant velocities. Related Articles | Metrics | Comments（0）

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A Study on Mine Detection and Identification Through Pattern Recognition with the Help of Multi-Features WANG Qun, NI Hong-wei, XU Yi-gang Journal of Applied Sciences    2003, 21 (1): 53-58.   Abstract （380）      PDF（pc） （670KB）（81）       Knowledge map    Save Based on the analysis of the echo from buried objects, a novel method of locating buried mines using pattern recognition is recommended. The process comprises pre-processing stage, feature-extraction stage, feature reduction and a neural network classification stage. A PNN neural network is employed to identify the objects by training it to recognize the features extracted from time domain and frequency domain, wavelet domain as well as Welch power spectral density estimation of signal segments reflected from various types of buried targets. The data concerning mines and some other objects which are like mines in shape and size are compared and tested with the network, and the results indicate that the neural network using multi-feature can improve mine detection greatly. Related Articles | Metrics | Comments（0） Cited: Baidu(13)

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A Correlation Analysis of Time-Variable Sequence Variable-Memory LU Shu-wang, LIU Chuan-dong Journal of Applied Sciences    2003, 21 (1): 59-62.   Abstract （319）      PDF（pc） （272KB）（74）       Knowledge map    Save The probability model of a class of combined pseudo -random sequence variable memory is suggested and analyzed, of which the main characteristic is given. The information leak caused by time-variable function while the output sequence is turning into the input sequence is analyzed. The quasi -like sequence method by which the output sequence constructs the input sequence of variable-memory threshold is suggested in this paper. Related Articles | Metrics | Comments（0）

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Restrictions on a Realizable Gait of a Biped Robot Climbing Upstairs KE Xian-xin, GONG Zhen-bang, WU Jia-qi Journal of Applied Sciences    2003, 21 (1): 63-67.   Abstract （391）      PDF（pc） （400KB）（82）       Knowledge map    Save The gait of a biped robot climbing stairs consists of foot trajectory and hip trajectory. Through analyzing the dynamical restrictions on stable walking and the geometry restrictions on the gait of a robot climbing stairs, the restrictions on a realizable gait of a robot climbing stairs were obtained. The simulations of climbing upstairs gait were presented. Related Articles | Metrics | Comments（0） Cited: Baidu(12)

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The Application of the FEM Technology on the Deformation Analysis of the Thin-Wall Workpieces Milling in Aerospace Industries WU Kai, HE Ning, JIANG Cheng-yu, HE Lei, ZHANG Ping, GONG Hui-min, CHEN Xue-mei Journal of Applied Sciences    2003, 21 (1): 68-71.   Abstract （410）      PDF（pc） （355KB）（163）       Knowledge map    Save Thin-wall structure workpieces are often used in aerospace industries. They are easy to deform in the process of machining and the deformation affects the dimension precision of the workpieces. This paper proposed a systematic method to ensure the dimension precision of the thin-wall workpieces in end milling. By using the mechanistic model developed by the author and the ANSYS FEM software, machining errors have been computed, and the results fit in with the actual machining process. Related Articles | Metrics | Comments（0） Cited: Baidu(20)

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Fatigue Analysis for the High-Speed Elastic Transporting Manipulator under Impact Condition WANG Guo-qing, LIU Hong-zhao Journal of Applied Sciences    2003, 21 (1): 72-76.   Abstract （277）      PDF（pc） （406KB）（78）       Knowledge map    Save To analyze the aeronautic high-speed elastic transporting maniplator fatigue in the experiment, this paper firstly takes account of the external oblique impact and inner contact resulting from a joint with clearance. Nonlinear spring and damper formulations are adopted to model the resulting reaction force between contact objects, then based on the finite element method, a dynamic model is established. By means of numerical simulations, the stress chart of dangerous sectional and fatigue life are investigated. The value of the fatigue life caculated is in accord with the experiment result. Related Articles | Metrics | Comments（0）

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Robust Fault Diagnosis for Nonlinear Systems Based on Least Squares Estimation CHEN Yu-dong, WENG Zheng-xin, SHI Song-jiao Journal of Applied Sciences    2003, 21 (1): 77-83.   Abstract （331）      PDF（pc） （553KB）（65）       Knowledge map    Save A fault diagnosis approach based on least squares estimation(FDBLSE) for a class of nonlinear systems is proposed in this paper. It first constructs a state estimator for the systems to be diagnosed so that the dynamic relationship between state estimation error and faults is obtained, it then identifies the faults using least squares estimation method based on the obtained dynamic relationship. The fault identification error and the robustness, sensitivity to faults and the detection time of the fault diagnosis are analyzed. A deep-going comparison between the approach proposed in this paper and the fault diagnosis approach based on the learning method is also given. FDBLSE approach can not only identify faults, but also give the upper limit of the identification error. It highlights short identification-time and high accuracy of fault identification. The simulation indicates the effectiveness of the approach proposed in this paper. Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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A Study on the Mixed Design of Active Control of Frame Structures ZHOU Xing-de, WANG Feng-quan, HAN Xiao-lin Journal of Applied Sciences    2003, 21 (1): 84-87.   Abstract （256）      PDF（pc） （342KB）（62）       Knowledge map    Save In order to reduce control energy needed for active vibration control of frame structures, a mixed design which combines structural design with controller design is considered. The original structures are redesigned to diminish control energy without affecting the basic performance and control effect of frame structures. Using systemic stability, controllability and other factors as restrictive conditions, a random structural dimension and material constant are chosen to acquire control energy through system reduction and controller design. And an improved genetic algorithm is used to search for optimal control energy. Finally, a numerical example is provided to show the effectiveness of the method. Related Articles | Metrics | Comments（0）

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A Random Simulation Model in Porous Media ZHANG Dong-hui, JIN Feng, SHI Ming-heng, YANG Hao Journal of Applied Sciences    2003, 21 (1): 88-92.   Abstract （332）      PDF（pc） （418KB）（111）       Knowledge map    Save The dispersion process in porous media is analysed and simulated by use of the random simulation method in this paper. Anomalous dispersion and the preferential path for dispersion flow are found near a percolation threshold caused by random pore removal or blockage. The calculated results show that the longitudinal dispersivity is greater when it is near a percolation threshold than in Euclidean space. Related Articles | Metrics | Comments（0） Cited: Baidu(5)

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A Study on the Design of Extra-Long Measuring Bars NIE Heng-jing, DENG Shan-xi, LIU Wen-wen Journal of Applied Sciences    2003, 21 (1): 93-95.   Abstract （340）      PDF（pc） （238KB）（74）       Knowledge map    Save A study on the performance of an extra-long measuring bar used for non-contact measurement of inner diameter and geometrical form in a long tube is reported in this paper. A method of pre-bending the measuring bar for compensating its elastic deflection is proposed. Thus, a straight measuring bar can be used to carry a sensor for accurate and steady data acquisition. Secondly, to avoid or reduce the effect of environmental vibration, the natural frequencies of measuring bar with two kinds of loads are analyzed, and a suggestion to reduce that effect is given in this paper. The research results are of universal significance for the design of various extra-long measuring bars. Related Articles | Metrics | Comments（0）

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Research on the Teeth Profile Error of Grinding Teeth TAO Xiao-jie Journal of Applied Sciences    2003, 21 (1): 96-98.   Abstract （453）      PDF（pc） （247KB）（133）       Knowledge map    Save The technological parameters are one of the key factors that cause the teeth profile error. The paper analyses the causes that lead to the teeth profile error when grinding teeth using a machine equipped with the coned shape grinding wheel is used. The relation formula between the teeth profile error and the parameters of technology was obtained after experiments and the main factors that affect the error were found. It is very important for us to reduce the profile error and increase gear precision. Related Articles | Metrics | Comments（0） Cited: Baidu(5)

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Some Sufficient Conditions for Hamilton Graph and a Conjeture ZHAO Ke-wen, WU Yan Journal of Applied Sciences    2003, 21 (1): 99-102.   Abstract （713）      PDF（pc） （312KB）（78）       Knowledge map    Save In this paper, let u, v, w be arbitrary vertices in simple graph of order n-G=(V,E) satisfing wu ∈V(G),d(u,v)=d(v,w)=2, with|N(u) ∪N(v)|+d(w) ≥ n, then G is Hamilto-nian. The result is better than those of other authors. Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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Fast Calculation of the Electromagnetic Scattering Directional Characteristics of Frequency Selective Surfaces TONG Chuang-ming, YUAN Nai-chang, FU Yun-qi, ZHANG Guo-hua Journal of Applied Sciences    2003, 21 (1): 103-106.   Abstract （455）      PDF（pc） （288KB）（72）       Knowledge map    Save The method of moments (MOM) in conjunction with the asymptotic waveform evaluation (AWE) technique is applied to calculate the electromagnetic scattering directional characteristics of one-dimensional frequency selective surfaces (FSS). The electric field integral equation (EFIE) of FSS irradiated by the electromagnetic (EM) wave is firstly changed into the matrix equations of the induced currents using MOM, and the matrix equations of an angular derivative (MEAD) can be then obtained from the matrix equations. In the AWE technique, the induced currents of angular derivative at a given angle within an angular are first obtained to find MEAD. The induced currents at any angle within the angle can be then obtained from the induced currents of an angular derivative at given angle via the Pade approximation. According to the induced currents and the Floquet harmonic of the spectral domain, the EM scattering directional characteristics can be calculated. It was observed that the results of AWE can exactly approximate those of MOM that sweeps frequency at a certain interval, and AWE technique can result in considerable CPU time saving. Related Articles | Metrics | Comments（0）

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Effects of Thermal Cycles on the Properties of CuZnAl Shape Memory Alloys SI Nai-chao, LIU Hai-xia, QI Long-biao Journal of Applied Sciences    2003, 21 (1): 107-110.   Abstract （355）      PDF（pc） （578KB）（77）       Knowledge map    Save The effects of thermal cycles on the properties of CuZnAl shape memory alloys under different heating temperatures, pre-deformations ε and amounts of complex rare earth mixture added were researched with electronic microscopes. The results indicate that thermal cycles can increase the transformation temperature Ms of the alloys by 5-6℃. Increasing the pre-deforma-tion ε will decrease the necessary cycle times for stable two-way-shape memory property. However the shape recovery rate of the alloys will decrease when the pre-deformation exceeds 3.6%. The shape memory property of the alloys will change insignificantly if the amount of rare earth added is less than 0.10%. But the alloys without rare earth will have worse shape memory property after thermal cycles reach 1800 times. Related Articles | Metrics | Comments（0）

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A Study of the Sound Absorption Property of Grain GUO Min, SHANG Zhi-yuan, SHI Huan-wen Journal of Applied Sciences    2003, 21 (2): 111-116.   Abstract （253）      PDF（pc） （516KB）（108）       Knowledge map    Save By using the method of standing wave tube, we studied the sound absorption coefficient of grain for the first time. The sound absorption property of the grain piled in different thickness was researched. We found the relationship between the sound absorption property of a pile of grain and its shape, size and thickness within the frequency range of 100~5000Hz. It was shown that grain is a highly sound-absorbing medium. The sound absorption property of a pile of grain has something to do with its shape, size and thickness. This study provides a theoretical base and helps to accumulate data for detecting sound signals of the pests in grain. Related Articles | Metrics | Comments（0） Cited: Baidu(6)

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A Multiple Time Scales Analysis of the Runoff Variation Along the Upper Reaches of the Yellow River LIU Jim-ping, TIAN Feng-wei, HUANG Qiang Journal of Applied Sciences    2003, 21 (2): 117-121.   Abstract （353）      PDF（pc） （406KB）（159）       Knowledge map    Save By applying the theory of wavelet transformation and the 1919-1996 natural runoff records of Lanzhou hydrometric station, the runoff variation along the upper reaches of the Yellow River is studied. The periods of runoff and points of abrupt change at different time scales are analyzed. The wavelet variance verification indicates that the main periods of the runoff variation along the upper reaches of the Yellow River are 22, 15, 4 and 37 years respectively in order of importance. Basing on the main period of 22 years, we predict that runoff will be in the dry period from about 1996 to about 2007. Related Articles | Metrics | Comments（0） Cited: Baidu(26)

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The Characteristics of Type V Intermittency Displayed in a Kind of Two-Dimensional Maps with a Background of Impact Oscillators ZHAO Jin-gang, CHAO Xiao-gang, WANG Wen-xiu, WANG Ying-mei, ZHANG Kai, WANG Xu-ming, HE Da-ren Journal of Applied Sciences    2003, 21 (2): 122-126.   Abstract （305）      PDF（pc） （422KB）（87）       Knowledge map    Save Type V intermittency is found to exist widely in a kind of two-dimensional maps with a background of impact oscillators. It has two characteristics. Firstly, the prelude phase-locking staircase to type V intermittency before entering chaos includes the traditional-like and multiple-like devil's staircase structures; secondly, the chaotic attractor appearing after the staircase is always the end-results of the image set of the discontinuous borderline. Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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Computing the Largest Lyapunov Exponent from Time Series LI Guo-hui, ZHOU Shi-ping, XU De-ming Journal of Applied Sciences    2003, 21 (2): 127-131.   Abstract （920）      PDF（pc） （388KB）（303）       Knowledge map    Save A method to calculate the largest Lyapunov exponent from the observed time series based on its definition is proposed. We have tested it on several known systems, such as the Logistic model, the Henon mapping and the Lorenz system. It is found that the estimated largest Lyapunov exponent from time series has a reasonable good accuracy. More remarkably, the simulation result is independent of the embedding dimension and the delay time to a certain extent. The shorter data and the lower dimension of phase space simplify the computation without significant loss of precision. Related Articles | Metrics | Comments（0） Cited: Baidu(24)

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The Triple I Algorithm for the Implication I(x,y) Operator Based on Vague Sets XU Zhang-yan, LI Fan, FENG Jia-li Journal of Applied Sciences    2003, 21 (2): 132-136.   Abstract （321）      PDF（pc） （426KB）（96）       Knowledge map    Save The definition of the implication operator of the interval set and a concrete implication operator are given. The calculation formulas of the triple IVMP algorithm for the implication I(x,y) operator based on Vague sets are obtained. The reversible properties of the triple IVMP algorithm are analyzed, and the essential conditions of the reversible properties of the triple IVMP algorithm for implication I(x,y) operator based on Vague sets are obtained. Because the Vague set is better than the Fuzzy set in expressing the uncertain knowledge, the triple I thinking is more believable and the triple IVMP algorithm is more satisfying in the uncertain reasoning. Related Articles | Metrics | Comments（0）

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A Research on the High Performance DCA-Tree Cube in the Multidimensional Data Warehouse System HU Kong-fa, DONG Yi-sheng, XU Li-zhen, ZHUANG Xiao-qing, YANG Ke-hua Journal of Applied Sciences    2003, 21 (2): 137-140.   Abstract （446）      PDF（pc） （321KB）（139）       Knowledge map    Save In this paper, the authors propose using the DCA-tree (a modified version of the R*-tree) to create the high performance data cube aggregate-tree cube (DCA-tree cube). The authors also describe the key techniques such as DCA-tree cube creating, MOLAP rapid querying, DCA-tree cube incremental updating, etc. The analytical result of the algorithm shows that the performance of the DCA-tree cube in querying and updating is better than that of the cube created by the aggregate techniques such as dynamic data cube (DDC), etc. The DCA-tree cube can update incrementally while new data of some dimensions are inserted. Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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Minimizing the Range of Lateness on a Single Machine with the Workpieces Processed in Batches CHENG Ming-bao, SUN Shi-jie, HE Long-min Journal of Applied Sciences    2003, 21 (2): 141-145.   Abstract （287）      PDF（pc） （391KB）（86）       Knowledge map    Save There are n workpieces to be processed at time zero. The length of time needed for processing them varies with each workpiece. The workpieces are divided into b batches, and all the workpieces in the same batch must be processed together, successively or at same time. The problem under consideration is to minimize the range of lateness. To solve such a scheduling problem, this paper determines some properties and constructs corresponding pseudopolynomial algorithms. Related Articles | Metrics | Comments（0） Cited: Baidu(2)

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The Strategy of Integrated Study of “Bluetooth” and the Intelligent Machine YIN Yue-hong, SHENG Xin-jun Journal of Applied Sciences    2003, 21 (2): 146-150.   Abstract （319）      PDF（pc） （475KB）（101）       Knowledge map    Save In this paper the strategy and key problems of integrated study on "Bluetooth" and the intelligent machine are illustrated in detail. A project-a recent study on Bluetooth-based Service Robot-is presented as an example. Related Articles | Metrics | Comments（0）

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The Design of Fuzzy Adaptive Robust Control Algorithm via the Dissipative System Theory Approach YANG Yan-sheng Journal of Applied Sciences    2003, 21 (2): 151-156.   Abstract （301）      PDF（pc） （462KB）（81）       Knowledge map    Save A new fuzzy adaptive robust control algorithm is presented for a class of uncertain nonlinear systems. In the algorithm, Takagi-Sugeno-type fuzzy logic systems are used to approximate unknown functions in the systems, and the adaptive mechanism with minimal learning pa-rameterizations can be achieved by using the dissipative system theory. An example illustrating the method of ship roll stabilization by the fin control system is included. It is shown that the designed system can guarantee the performance of the global asymptotic stability. Related Articles | Metrics | Comments（0）

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The Power Spectrum Estimation Method Based on Continuous Wavelet Transformation XU Ke-jun, LI Yong-san Journal of Applied Sciences    2003, 21 (2): 157-160.   Abstract （447）      PDF（pc） （316KB）（223）       Knowledge map    Save According to the idea of the power spectrum analog analysis method, the power spectrum of signal is estimated by using the continuous wavelet transformation. The basic principle of the power spectrum estimation is presented and the program flow given. The simulation results which are compared with the power spectrum estimation method based on FFT are presented in this paper. Related Articles | Metrics | Comments（0） Cited: Baidu(21)

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A Parametric Integration to Solve Axisymmetric Indentation of Semi-Infinite Medium by a Flat-Round Punch ZHAO De-wen, WANG Xiao-wen, LIU Xiang-hua, WANG Guo-dong Journal of Applied Sciences    2003, 21 (2): 161-164.   Abstract （325）      PDF（pc） （301KB）（70）       Knowledge map    Save A parametric equation to establish velocity field for the indentation of semi-infinite medium by a flat-round punch was proposed, and corresponding parametric integration to deformation power was performed as a new method in this paper. A minimal analytical upper-bound solution of stress state factor for the indentation was obtained. The result is shown to be lower than that of triangle velocity field for the plane-strain indentation. Related Articles | Metrics | Comments（0）

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A Research on Interpart Feature Modeling HUANG Xiang, YAN Chong-jing Journal of Applied Sciences    2003, 21 (2): 165-167.   Abstract （298）      PDF（pc） （286KB）（82）       Knowledge map    Save A new method, virtual-part-based interpart feature modeling, and its mathematical representation are proposed in this paper. It extends the single part feature-based modeling to interpart feature modeling. In this way, local modification of the solid model of base parts is done by Boolean operation between base parts and the virtual part. Assemblying and part modeling are conducted simultaneously. So it greatly increases modeling efficiency, assures interpart associativity, and the design knowledge can be encapsulated conveniently through the virtual part. etc.. A rapid design system of mechanical connecting elements is thus developed in UG. Related Articles | Metrics | Comments（0）

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The Exergoeconomical Optimal Performances of a Three-Heat-Source Refrigerator YANG Hui-shan Journal of Applied Sciences    2003, 21 (2): 168-172.   Abstract （339）      PDF（pc） （398KB）（85）       Knowledge map    Save An optimal analysis based on the rate of profit objective function is carried out on a class of three-heat-source refrigerators working under the operation of the Newton' heat transfer law. The exergoeconomical optimal performance of refrigerator is derived, and the internal relation between it and the ecological optimal performance is revealed. The conclusions obtained here may provide some new theoretical guidance for the manufacture and the optimal design of three-heat-source refrigerators. Related Articles | Metrics | Comments（0）

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Size Effect in Ferroelectric Switching XU Rong-qing, ZHOU Qing-chun, WANG Mao-xiang Journal of Applied Sciences    2003, 21 (2): 173-176.   Abstract （328）      PDF（pc） （327KB）（104）       Knowledge map    Save The Orihara-Ishibashi theory of finite ferroelectric system is applied to the cubic ferro-electrics. The expressions of the ratio of the reversed domain volume to the system volume Q(t) and the reversal rate dQ/dt which is closely related to the switching current, are given for cubic domain reversals. Computations indicate that the switching current drops with the size of the ferroelectric system, and in a certain range of l(l<0. 75), the switching time also decreases with l. Related Articles | Metrics | Comments（0） Cited: Baidu(8)

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The Performance of the DCF Transmission System WANG Chen, RAO Min, TANG Rong, LI Lei, ZHANG Ming-de, SUN Xiao-han Journal of Applied Sciences    2003, 21 (2): 177-181.   Abstract （286）      PDF（pc） （460KB）（157）       Knowledge map    Save The effects of nonlinear effects on the WDM system are presented here. Through the simulation of the DCF transmission system with different schemes, the optimized scheme of transmission link and input power is obtained. The results show that the transmission performance of mix-compensation is better than that of pre-compensation and post-compensation. The transmission performances of the various channels are compared. Related Articles | Metrics | Comments（0） Cited: Baidu(9)

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A Low-Complexity Modulation Scheme for DAMB SHU Feng, LI Chong-yi, ZHAO Guang-ling, WU Le-Nan Journal of Applied Sciences    2003, 21 (2): 182-186.   Abstract （253）      PDF（pc） （425KB）（124）       Knowledge map    Save The time-domain DAPSK+OFDM is proposed for digital amplitude modulation broadcast (DAMB), which offers a low-complexity uncoded modulation scheme. First, the AM channel model below 30MHz is described, and the baseband model based on the OFDM system is shown. Next, the modulation, demodulation and BER performance of 32DAPSK4-OFDM are investigated in AWGN channel. Finally, the BER performance of 32DAPSK + OFDM is simulated in all the AM channels. Related Articles | Metrics | Comments（0） Cited: Baidu(1)

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