JOURNAL OF BEIJING INSTITUTE OF TECHNOLOGY

Existence of Multiple Solutions for a Superlinear Sturm Liouville BVPs

SUN Wei-ping, GE Wei-gao

2000, 9(1): 1-4.

[Abstract](232)

Abstract:
The existence of solutions of a Sturm Liouville boundary value problem(BVP) for u″+g(u)=p(t,u,u′)(0≤t≤1) is studied by using a continuation theorem based on the topological degree theory. Under the condition that g grows superlinearly andpgrows with respect to u and u′ linearly at most, the boundary value problem has an infinitude of solutions.

Poisson Theory of Generalized Birkhoff Systems

LIANG Jing-hui, LI Yuan-cheng, MEI Feng-xiang

2000, 9(1): 5-10.

[Abstract](178) [PDF 178KB](2)

Abstract:
To study the Poisson theory of the generalized Birkhoff systems, the Lie algebra and the Poisson brackets were used to establish the Poisson theorem. The generalized Poisson condition for the first integral and the generalized Poisson theorem of the generalized Birkhoff systems are obtained. An example is given to illustrate the application of the result.

Lie Symmetries and Conserved Quantities for the Singular Lagrange System

MEI Feng-xiang, ZHU Hai-ping

2000, 9(1): 11-14.

[Abstract](183) [PDF 138KB](2)

Abstract:
The invariance of the ordinary differential equations under the infinitesimal transformations was used to study the Lie symmetries and conserved quantities for the singular Lagrange system. The determining equations, the restriction equations of the Lie symmetries and the form of conserved quantities of the system are obtained.

Method of Semi Analytic Perturbation Weighted Residuals for Nonlinear Bending of Shallow Shells

LI Yun-fei, HUANG Yi-jun

2000, 9(1): 15-19.

[Abstract](184)

Abstract:
The semi-analytic perturbation weighted residuals method was used to solve the nonlinear bending problem of shallow shells, and the fifth order B spline was taken as trial function to seek an efficient method for nonlinear bending problem of shallow shells. The results from the present method are in good agreement with those derived from other methods. The present method is of higher accuracy, lower computing time and wider adaptability. In addition, the design of computer program is simple and it is easy to be programmed.

Self Dual Structure of Conformal Supergravity

JIA Yan-hua, MEI Feng-xiang, QI Guo-ying

2000, 9(1): 20-24.

[Abstract](270)

Abstract:
On the basis of a unified definition of the dual operation and the (anti)self dual operation, the connections of the su(2,2｜1) main cluster was used as the fundamental field variables to construct the self dual Lagrangian of conformal supergravity. A Yang Mill like Lagrangian is obtained and a new gauge theory of supergravity is put forward. The spatial projects of its spin connection are Ashtekar variables.

Quantitative Relationship Between Simultaneous Color Contrast and Hue Difference in Complex Displays

LI Wei, TANG Yu-chun

2000, 9(1): 25-30.

[Abstract](195)

Abstract:
To investigate quantitatively one of the parametric effects——simultaneous color contrast on color appearance and color difference evaluation in complex displays, a set of center/surround combinations of color stimuli were displayed on a color monitor and the perceived color shifts of test targets induced by its surrounds were measured using binocular matching method while systematically varying hue difference between target and surround. When the hue difference increased, the magnitude of color shift in test target decreased, but the deflection angle of color shift vector from constant hue line increased. Regression analyses of experimental data indicated that the relationship between hue angle difference and the magnitude of perceived color shifts could be described quantitatively by an exponential function, and a linear function could describe quantitative relationship between hue angle difference and deflection angle of color shift vector from constant hue line.

Neural Network Method for Colorimetry Calibration of Video Cameras

ZHOU Shuang-quan, ZHAO Da-zun

2000, 9(1): 31-36.

[Abstract](237)

Abstract:
To transfer the color data from a device (video camera)-dependent color space into a device-independent color space, a multilayer feedforward network with the error backpropa-gation (BP) learning rule, was regarded as a nonlinear transformer realizing the mapping from the RGB color space to CIELAB color space. A variety of mapping accuracy were obtained with different network structures. BP neural networks can provide a satisfactory mapping accuracy in the field of color space transformation for video cameras.

Study on Tri-Stimulus Transformation

ZHOU Shuang-quan, ZHAO Da-zun

2000, 9(1): 37-44.

[Abstract](169)

Abstract:
To decrease number of samples for the implementation of color space transformation, a method for modeling the chromatic characterization of video cameras was proposed. An additional transformation was required to predict output RGB values for an input color. This additional transformation was based on spectral reflectance relationship. The transformed color coordinates were taken as inputs of a multilayer neural network. Based on network outputs, the RGB values to be predicted were calculated. Experimental results were given to illustrate the performance of the method. Even though much less number of training samples are used, this method can also perform well on this color space transformation.

Schrdinger Cat States in a Mesoscopic Josephson Junction

ZOU Jian, SHAO Bin, XING Xiu-san

2000, 9(1): 45-48.

[Abstract](165)

Abstract:
To study the nonclassical effects of the mesoscopic Josephson junction in the presence of a nonclassical microwave, the mesoscopic Josephson junction and the field were both treated quantum mechanically, and the external field approximation was used. It is shown that if the external field is in the coherent state and the state of the junction is initially prepared in the vacuum state, the state of the junction can evolve into a quantum superposition of two coherent states. The Schrdinger cat states can be produced in a mesoscopic Josephson junction.

Multisensor Fuzzy Stochastic Fusion Based on Genetic Algorithms

HU Chang-zhen, TAN Hui-min

2000, 9(1): 49-54.

[Abstract](205)

Abstract:
To establish a parallel fusion approach of processing high dimensional information, the model and criterion of multisensor fuzzy stochastic data fusion were presented. In order to design genetic algorithm fusion, the fusion parameter coding, initial population and fitness function es-tablishing, and fuzzy logic controller designing for genetic operations and probability choosing were completed. The discussion on the highly dimensional fusion was given. For a moving tar-get with the division of 1.64 (velocity) and 1.75 (acceleration), the precision of fusion is 0.94 and 0.98 respectively. The fusion approach can improve the reliability and decision precision effectively.

Knowledge Discovery in Maintenance Record of FMS Equipment for Diagnosing

ZHU Xiao-yan, HOU Li-hua, TANG Shui-yuan

2000, 9(1): 55-60.

[Abstract](264)

Abstract:
To discover the knowledge of fault diagnosis in maintenance record of flexible manufacture system(FMS) equipment. An algorithm (process) was presented, which consists of ① preparatory phase in which some items in maintenance record are selected and decomposed into associated concepts and attributes, and ② discovering and establishing process, in which some possible relationships between the concepts and attributes can be established and knowledge is formulated. The rich diagnosis knowledge in maintenance record was captured through applying the method. An application of the method to the diagnosis system for FMS equipment showed that the approach is correct and effective.

Experimental Research on Enhanced Cyclone Separation of Acoustic Agglomerated Particles

LIU Shu-yan, HUANG Hong-bin, YAN Wei-ge

2000, 9(1): 61-65.

[Abstract](196)

Abstract:
To test the particles solidity and to verify the separating efficiency at normal atmospheric temperature, the experimental research was made on the enhanced cyclone separation of acoustic agglomerated fly ash particles. The separating efficiency has increased by 3%-4% in a sound field with 150 dB pressure level compared with that obtained without acoustic wave processing. The enhanced cyclone separation test study for acoustic agglomerated particles has provided a technical basis for pressurized fluid bed combustion(PFBC) application.

Automated Registration for Infrared Image Based on Wavelet Analysis

NIU Yong-sheng, NI Guo-qiang

2000, 9(1): 66-72.

[Abstract](276)

Abstract:
To develop a quick, accurate and antinoise automated image registration technique for infrared images, the wavelet analysis technique was used to extract the feature points in two images followed by the compensation for input image with angle difference between them. A hi erarchical feature matching algorithm was adopted to get the final transform parameters between the two images. The simulation results for two infrared images show that the method can effectively, quickly and accurately register images and be antinoise to some extent.

Interrupt CW Approach for IF Video Signal Real Time Simulating and Its Validity

ZHU Can-yan, LONG Teng, HE Pei-kun, MAO Er-ke

2000, 9(1): 73-79.

[Abstract](192)

Abstract:
To determine the feasibility and practicability of interrupt continuous wave (CW) approach proposed for real time simulating radar intermediate frequency(IF) video signal, theoretical analysis and computer simulation were used. Phases at two linked points between the end and beginning of adjoined frames are always consistent;the bias Doppler frequency for the time delay of A/D sampling start responds to that for target acceleration. No digital phase compensation is required at continuous points, and the interrupt CW approach has apparently practical values.

Theoretical Study of Double Cost Function Linear Quadratic Regulator(LQR)

JIANG Lan, WANG Xin-yi, Nagai Masao

2000, 9(1): 80-86.

[Abstract](294) [PDF 233KB](3)

Abstract:
Double cost function linear quadratic regulator (DLQR) is developed from LQR theory to solve an optimal control problem with a general nonlinear cost function. In addition to the traditional LQ cost function, another free form cost function was introduced to express the physical need plainly and optimize weights of LQ cost function using the search algorithms. As an instance, DLQR was applied in determining the control input in the front steering angle compensation control (FSAC) model for heavy duty vehicles. The brief simulations show that DLQR is powerful enough to specify the engineering requirements correctly and balance many factors effectively. The concept and applicable field of LQR are expanded by DLQR to optimize the system with a free form cost function.

Distribution and Dissipation of Braking Power of Wet Multidisc Brake

YAN Qing-dong, SU Xin-dong

2000, 9(1): 87-93.

[Abstract](183)

Abstract:
To study the distribution and dissipation of braking power of wet multidisc brake and determine thermal load and thermal flux distribution between mated discs, the concept of distributing brake power four times was put forward. The third and the fourth distribution of brake power were calculated by using finite element(FE) software ANSYS. The third and the fourth distribution of wet multidisc brake are mainly related to material characteristics of discs during emergency braking, while most of the braking power is carried off during continuous braking. Basis is provided for further analysis of disc failure and applicability of different friction materials.

Development of Management Systems for Electric Vehicle Battery Series

ZHANG Cheng-ning, SUN Feng-chun, ZHAO Hong-jie, SUN Li-qing

2000, 9(1): 94-100.

[Abstract](241) [PDF 269KB](3)

Abstract:
A kind of management system for electric vehicle (EV) battery series was developed. The system can predict residual capacity for EV battery series and mileages. The system can determine if it is necessary for the battery series to be charged. The system can determine which battery is necessary to be updated for the reason of damage or aging. The system can display the total voltage of battery series, extreme voltage and temperature of every battery in the series. The system can display the accumulative discharge for every battery in the series. The system can alarm when both total or extreme voltage is at low level, or temperature of a battery in the series is at high level. The system provided with a microprocessor as key part can collect and record signal of charging and discharging current, total voltage, extreme voltage and temperature for every battery. The mathematical model of residual capacity for EV lead acid batteries was discussed in details. The system operates well in the laboratory and meets the requirement.

Multi-Component Signal Processing for the Short Range Radar

LI Guo-lin, SHI Ju-sheng, ZHAO Xi, ZHANG Xu

2000, 9(1): 101-106.

[Abstract](232)

Abstract:
To study the measurement of distance under the condition of the frequency modulation (FM) multi component signal of a short range radar, the multi points scattering model of a target, the TLS ESPRIT (total least square estimation of signal parameters via rotational invariance techniques) and the mathematical statistics methods were used. The method of computing single frequency signal's instantaneous frequency (IF) is unsuitable to the multi component signal. By using the method of the TLS ESPRIT combined with the mathematical statistics, the multi component signal's IF can be obtained. The computer simulation has shown that the method has the high accuracy for measuring the distance.

Design and Simulation of Controller for Hyper Velocity Kinetic Energy Missile

KANG Chang-geng, LEI Cheng, LIU Zao-zhen

2000, 9(1): 107-112.

[Abstract](206)

Abstract:
The controller design and digital simulation for the hyper velocity kinetic energy missile is investigated. A mathematical model of the trajectory deviation from the line of sight was established, the guidance closed loop was compensated with a phase advance lag corrective network, a selecting algorithm of the attitude control motors used to steer the missile's attitude was presented. In the presence of a wide variety of disturbances the results of digital simulation are satisfactory to circular error probability(CEP) being less than 0 5?m. The steering scheme utilizing attitude control motors as actuators to control the attitude of the missile is feasible.

2000 Vol. 9, No. 1