西南交通大学学报

Auxiliary Train Location Technique with Registration Arms of Electrified Railways

MA Yong-qiang, GUO Jin

2005, 18(1): 1-4.

[Abstract](1741)

Abstract:
A train positioning technique was proposed as an auxiliary measure for the train locating system based on balise system and odometer. The technique uses the detected location signal at each registration arm to correct the errors accumulated in the odometer. An inspecting window is used in detection of registration arms to avoid interferences from background objects. This auxiliary locating technique brings much higher precision on train location and requires much less balise devices.

Numerical Calculation for Turbulent Flow around TR Maglev Train

BIHai-qua, LEI Bo, ZHANG Wei-hua

2005, 18(1): 5-8.

[Abstract](1481)

Abstract:
Based on the Navier-Stokes equation of compressible viscosity fluid and thek-εturbulence model, turbulent flow around a TR (Transrapid) maglev train with a speed of 430 km/h was investigated using the finite volume method, and the pressure and velocity distributions of slipstream around the train were gained. The research results show that the changes of velocity and pressure within 2 m away from train s top and two side surfaces are respectively more than 10 m/s and 1.3 kPa, while at the height of 2 m away from the ground, they are respectively less than 5 m/s and 0. 7 kPa.

Comparison of Algorithms for Discontinuity on the Characteristics Curves of Draft Gears

HUANG Yun-hua, LI Fu, FU Mao-hai, BUJi-ling

2005, 18(1): 9-13.

[Abstract](1501)

Abstract:
Four kinds of algorithms dealing with discontinuity on the characteristic curves of draft gears were discussed and compared. They are time method, velocity method, displacement method and force equilibrium method. Their applications were analyzed, and their advantages and disadvantages were compared in detail. The analysis results show that velocity method is superior to other methods in terms of easy application.

Variable-Air-Volume Air-Conditioning System Based on PID-ANN Decoupling Control Technology

FU Long-hai, LI Meng

2005, 18(1): 13-17.

[Abstract](1523)

Abstract:
A dynamic model for a transducer-electromotor-pressure loop and a fresh air valve-CO2 volume content loop was established in order to eliminate the coupling of each loop in a variable-air- volume (VAV) air-conditioning system and effectively control the system. In addition, decoupling control technology based on the PID (proportion-integral-differential) ANN (artificial neural network) was used to eliminate the coupling between the two loops. Its operation condition shows that the decoupling control technology based on the PID ANN is feasible to the decoupling control of the two loops in a VAV air-conditioning system.

Controlling Chaotic Motions of Nonlinear System Using B-Spline Neural Network

LIU Qi-lie, ZHANG Cui-fang, YI Fan

2005, 18(1): 18-21.

[Abstract](1496)

Abstract:
A B-spline neural network was trained to be a neural network chaotic controller to predict the time sequences of chaotic systems and obtain their perturbation signals for control of chaotic systems. The data around the fixed points of unstable periodic orbits were used as input samples to train the parametric perturbation model. The perturbation signals were embedded in a chaotic attractor on the inputs of parameter perturbation model. Numerical simulation on Henon mapping demonstrates that the proposed model is effective for nonlinear chaotic motion control.

New Fuzzy Self-Tuning Genetic Algorithm

FANG Lei, ZHANG Huan-chun, JING Ya-zhi

2005, 18(1): 22-25.

[Abstract](1625)

Abstract:
To overcome the drawback of“early maturing”of the classical genetic algorithm (GA) and improve its global convergency and convergency speed, a new fuzzy self-tuning genetic algorithm was proposed. In the new algorithm, the overall population is divided into several sub- populations and each sub-population has its own operators. Fuzzy reasoning is applied to give effective operators more opportunity to search under the condition of keeping the overall population size unchanged. The fuzzy reasoning can sense the contributions of these operators and then decides their population size. Simulation result of function optimization shows that with the proposed algorithm, the phenomenon of the“early maturing”can be effectively overcome, and a satisfying optimization result can be obtained.

Algorithms of Mining Fuzzy Association Rules

GAO Ya, MA Lin, DAI Qi

2005, 18(1): 26-29.

[Abstract](1299)

Abstract:
To raise the mining efficiency of fuzzy association rules, a redundant fuzzy association rule was defined and the redundant properties of strong fuzzy association rules were analyzed. A new algorithm to raise the mining efficiency by removing redundant fuzzy association rules was proposed. In addition, results obtained by two algorithms,i.e., removing redundant fuzzy association rules or not, were compared respectively with experimental results for the mining of strong fuzzy association rules defined by support and implication degrees. The research result shows that the algorithm of removing redundant fuzzy association rules can raise the mining efficiency.

Controllable Predictive Search Algorithm for Fast Block Motion Estimation

YANG Tian-wu, PENG Qiang, ZHU Chang-qian

2005, 18(1): 30-34.

[Abstract](1108)

Abstract:
Based on the characteristics of the diamond search, the concept of search length was brought forth. A novel controllable predictive cross-square fast search algorithm was proposed through investigating the characters of checking points with different search lengths. The proposed algorithm takes concepts of“stop when good enough”spirit and MIPC (multiple initial predictor candidates) in PMVFAST (predictive motion vector field adaptive search technique) algorithm. In the proposed algorithm, controllable predictive search criteria are set down based on the statistical characteristics of block distortion of checking points. Simulated experiments show that the proposed algorithm can obtain a better video quality than the other search algorithms. In addition, it has a good control capability of search speed, and its search speed can increase 1.5 to 2.5 times with less than 0.05 dB degradation of video quality.

Real-Time Data Acquisition Method Based on Active Data Sending/Serialport Data Monitoring

HUA Ze-xi, WANG Chang-lin, YIN Zhong-ke, ZHANG Chong

2005, 18(1): 35-38.

[Abstract](1197)

Abstract:
To resolve the real-time problem in data acquisition, a new real-time data acquisition method was proposed. In this method, actively sending data to serialport is created on intelligent equipment and a thread program of serialport monitoring is created based on multithreading technology. Handshake and end-connecting processes in conventional serialport communication are taken out from the procedure of data acquisition, and the reliability of the system can be guaranteed. The experimental results show that data transmitting time is shortened to 20% of the original transmitting time when transmitted data are 20 bytes per time. The proposed method has been applied to practice.

Extension to TTCN-3 Synchronization

SONG Bo, LI Xiu-feng, JIANG Chao-zhe

2005, 18(1): 39-43.

[Abstract](1321)

Abstract:
The shortcomings of present TTCN-3 (the testing and test control notation, version 3) in describing synchronization and the necessity of its extensions were analyzed. A new test frame was introduced. The extensions to TTCN-3 was implemented by analyzing an example and using the concept of semaphore. These extensions make test description easier and simpler.

Comparison among Methods of Decision Tree Pruning

WEIHong-ning

2005, 18(1): 44-48.

[Abstract](1489)

Abstract:
To select a suitable pruning method in decision tree pruning, four well-known pruning methods were compared in terms of computational complexity, traversal strategy, error estimation and theoretical principle by taking a classification and regression tree as an example. Compared with pessimistic error pruning (PEP), minimum error pruning (MEP) is less accurate and produces a larger tree. Reduced error pruning (REP) is one of the simplest pruning strategies, but it has the disadvantage of requiring a separate data set for pruning. Cost-complexity pruning (CCP) produces a smaller tree than REP with similar accuracy. Practically, if the training data is abundant, REP is preferable; and if the train data is the expected accuracy is high but with limited data, PEP is good choice.

Extension of Search Strategies on Ideal AND/OR Graphs

YANG Ning-xue, GONG Hui

2005, 18(1): 49-52.

[Abstract](1212)

Abstract:
SUB and COM are very important operators frequently used in reasoning network graphs of expert systems. AND and OR are the special cases of SUB and COM. The half scenery search method and the maximum superiority search method developed for searching ideal AND/OR graphs can be extended to searching ideal non-AND/OR graphs containing SUB and COM operators, and the maximum reliability search method for searching ideal AND/OR graphs is applicable to the non- ideal AND/OR graphs containing circuit structures.

Coupled Vibration Analysis of X-Style Arch Bridge and Vehicles

SHAN De-shan, LI Qiao

2005, 18(1): 53-58.

[Abstract](1497)

Abstract:
Based on the coupled vibration theory, dynamical models and equations of motion were set up respectively to an X-style arch bridge and vehicles. Vehicles and X-style arch bridge were divided into two vibration subsystems connected by nonlinear contact forces between wheels and tracks, and the iteration method was used to solve the two subsystems. A self-developed software analyzing the coupled vibration of vehicles and bridge was applied to an X-style railway arch bridge. The vertical and transverse displacements of this bridge, its dynamic amplificatory factor, and the derailment and offload factors of vehicles were evaluated. The result shows that under the discussed conditions, they all meet the current national criteria.

Analysis of Modal Properties of Cable-Net Structures

ZHENG Jia-shu, YUZhi-xiang

2005, 18(1): 58-63.

[Abstract](1259)

Abstract:
The modal properties of two practical cable-net structures, as examples, were analyzed with the sub-space iteration method to investigate the characteristic of frequency distribution of general cable-net structures and the effects of structural parameters, such as steel cable stiffness, structure mass and rise to span ratio, on their free vibration properties. In addition, the modal analysis considering geometry update was carried out. The research results show that the vibration modes of a cable-net structure are close each other, the initial tensile force and the structure mass are two important factors influencing the free vibration properties of a cable-net structure.

Finite Element Analysis of Shear Lag Effect of Skew Box Girder Bridges

ZHANG Yuan-hai, LI Qiao

2005, 18(1): 64-68.

[Abstract](1531)

Abstract:
The generalized conforming element for thin plate bending and the membrane element for plane stress were combined to obtain a plane shell element to analyze the shear lag effect for continuous skew box girder bridges. Comparison between experimental and computed results proved the effectiveness of this analytical method in the three-dimensional analysis of skew box girder bridges. As an example, skew box girders with different degrees of skew were analyzed respectively to investigate longitudinal and transversal distributions of shear lag effect under concentrated or uniform force, and were compared with the corresponding right box girders. The result shows that a skew box girder has more remarkable shear lag behavior than a right box girder. Shear lag effect must be fully considered in the design of a skew box girder.

Adjustment Function of Tie Bars of Long-Span Arch and Rigid Frame Combination Bridge

WANPeng, ZHENG Kai-feng, LIJie

2005, 18(1): 69-72.

[Abstract](1330)

Abstract:
A three-dimensional FE (finite element) model was established for a long-span arch and rigid frame combination bridge using software SAP2000 in order to solve the problem of interaction induced by tensioning the tie bars of rigid frame and main span and adjust its internal forces and geometry. To meet the requirements for stresses and deformations in the key locations of the combination bridge, reasonable tensioning forces were determined on the basis of construction processes. The result shows that the tensioning force of main span is mainly undertaken by rigid frame. Finally, it was pointed out that the influence of geometrical nonlinearity on internal forces may be ignored under the condition of dead load.

Experimental Investigation on Shear Strength Parameters of Jointed Rock Mass

ZHOU Ying-hua, ZHOU De-pei, YANG Tao, FENG Zhi-jun

2005, 18(1): 73-76.

[Abstract](1401)

Abstract:
Laboratory tests were performed on red bed soft rocks. The results show that shear strength parameters from a shear test and a triaxial compressive test are not consistent, and that friction angle changes with a regularity of continuous decreasing from the shear of intact rock to the triaxial compression of rock mass to the shear of structural planes. From the above experimental results, reasons for the difference between the three tests were analyzed respectively based on the strength theory of rock and the methods of laboratory tests. Relationships between the shear strength parameters of rock mass from a triaxial test and the shear strength parameters of structural planes were set up. In addition, the principles of determining the shear strength parameters of rock mass were put forward.

Investigation on Size Effect of Shear Strength of Soil

ZHOUJiang-ping, PENG Xiong-zhi

2005, 18(1): 77-81.

[Abstract](1249)

Abstract:
Based on the micro mechanical feature of materials and the strength theory of fibrous bunchiness, the macro statistical size effect of materials was gained. As an example, the shear strength of specimens from a concrete project with three scales,i.e.,small, medium and big sizes widely adopted in soil strength tests, was discussed using the statistical analysis and the Monte-Carlo method. The result shows the statistical size effect of soil shear strength. The research indicates that different sizes of specimens result in different values of soil shear strength, and this phenomenon can be well explained using the strength theory of fibrous bunchiness. When the size of a soil specimen is bigger than medium size, its shear strength tends to be unchanged.

Multidimensional Game Analysis of Pricing and Inputs of Advertisement and Services

TAN De-qing, HUPei, ZHU Wei

2005, 18(1): 82-84.

[Abstract](1131)

Abstract:
According to the characteristics of competition in market among modern firms, a multidimensional game model for two firms about pricing and the inputs of advertisement and services was established and its equilibrium solution was obtained. The analysis of the equilibrium solution shows that a firm can maximize its profit by synthetically considering the three factors and selecting an optimal strategic vector

Mining of Common Decision Knowledge of Specialists in Project Evaluation Using Rough Set Theory

LAN Min

2005, 18(1): 85-89.

[Abstract](1438)

Abstract:
The rough set model algorithm based on the decision table was used in project evaluation to acquire common decision knowledge from decisions of many specialists as the criterion and the final result of project evaluation so as to improve the existing evaluation algorithm. With this algorithm, the most important factors for decision-making in a condition attribute set and the rules of data mining can be determined. In addition, it was proposed that the reduction of the condition attribute set is used as a new condition attribute set in order to reduce the complexity of decision- making and avoid the irregularity of the individual of decision-makers under the precondition of not influencing the result of decision-making.

Game Analysis of Present System for Determination of Supervisory Prices in China

GUO Han-ding, LIU Ying-zong, HAO Hai

2005, 18(1): 90-93.

[Abstract](1329)

Abstract:
Game process for action tactics between the government and quality supervision organizations was analyzed with principal-agent theory. The analysis of the probabilities under different supervisory efficiencies suggests that the government needs to adjust the supervision policies and design effective incentive mechanism, guiding supervision organizations to strengthen their competitive powers by enhancing technical competence and realize the maximum social and environmental benefits for the government and economic returns for supervisory organizations.

Capacity Allocation Model for Container Logistics Revenue Management

BUXiang-zhi, HUANG Qing, WUZhen-ye

2005, 18(1): 94-98.

[Abstract](1386)

Abstract:
The framework for studying revenue management in container shipping industry under uncertainty was proposed. A stochastic container slot allocation model was established, and the uncertainty of demands among ports in a sea route was taken into account in the model. The algorithm for solving the model using the method of chance constrained programming was presented. Simulation results validate the model and show that the ship capacity affects the allocation policy greatly under great demands, and that the variation of demands also has great influence on slot allocation policy.

Matter Element Analysis of Competence of Top-Management

TANG Chun-yong, ZHOU Ying

2005, 18(1): 99-103.

[Abstract](1339)

Abstract:
The method of matter element analysis was used to build a model for evaluate competence of top-management in enterprises. It consists of three dimensions: managerial skills, personal traits and interpersonal relationship. A correlation degree was taken as the evaluating index, and a case was presented to show the application of the proposed method. The model is a combination of quantitative and qualitative analyses, primarily forming a mathematical model and an evaluating method for researches on competence of top-management.

Quality Factor of the Resonance Cavity Filled with Dilute Magnetic Material

ZHANG Shuang-wen, GUAN Zheng-tao, LIU Yun-lin

2005, 18(1): 104-107.

[Abstract](993)

Abstract:
magnetic material; resonance cavity; relative permeability; dielectric loss; quality factor

Application of PML Absorbing Boundary Condition in Numerical Simulation of Pulses Coupling into Slot

YANG Dan, FANG Jian, LIAO Cheng, REN Lang

2005, 18(1): 108-112.

[Abstract](1452)

Abstract:
Finite-difference time-domain method (FDTD) was used to simulate the coupling processes of ultra-wide-band (UWB) electromagnetic pulses into a cavity with a slot, and an anisotropic perfectly matched layer (PML) absorbing medium was inserted to truncate the computational lattices. According to the symmetry of the object and examining the special nodes of grids, the effectiveness of UWB pulses coupling into the whole cavity with a slot was obtained. The results show that the uniaxial PML is a suitable absorbing boundary condition for computing the problems of pulses coupling into slots.

Asymptotic Theory for Nonlinear Klein-Gordon Equations

JIANG Liang-jun, JIANG Liang-chun

2005, 18(1): 113-117.

[Abstract](939)

Abstract:
The asymptotic theory of Cauchy problems forn-dimensional Klein-Gordon equations was studied with global iterative technique. The well-posedness of the problem and the validity of formal approximations on a long time scalet∈[0,T(ε)), whereεis a small parameter, were proved in a proper Sobolev space.

On the Representation Theorems of Fuzzy Rough Sets

DU Wei-feng, SUN Shi-bao

2005, 18(1): 118-121.

[Abstract](1250)

Abstract:
The upper and lower approximation operators of rough set were defined by dual form. The representation theorems for this kind of fuzzy rough sets were presented using cut set of relative fuzzy relation and fuzzy sets. It is proved that the upper approximation of such fuzzy rough set in a fuzzy approximation space is just its image derived according to generalized extension principle and binary fuzzy similar relation. It is also proved that ZadehK s fuzzy Compositional Rule of Inference (CRI) has the same form with the specific generalized extension principle, and the inference result can be obtained through it. Thus, fuzzy inference can be studied with the help of the properties of generalized extension principle and rough set theory.

High Productivity Procedures of Flash Welding or Rails Based on Maximum Output Power

LüQi-bing, TAN Ke-li, DAIHong

2005, 18(1): 122-125.

[Abstract](1403)

Abstract:
According to equivalent circuit of the main welding circuit, a mathematic model was derived for maximum output power of theК-type alternative current rail flash butt welding machines. Based on the model, a high efficiency welding procedure was proposed, and the control program was designed. Experiments were conducted on aК900 rail flash welding machine by setting different welding currents at high voltage stages to determine the time at this stage. The experimental results indicate that welding time at high voltage stages is short when welding current at high voltage stage is close to the welding current corresponding to highest output power of the machine. Therefore, with the proposed procedure, the rail under welding can be heated fast, shortening the welding time and increase the productivity.

Hydrolysis Rate of Solid Waste in Bioreactor Landfill

LI Qi-bin, LIU Dan, OU-YANG Feng

2005, 18(1): 126-130.

[Abstract](1370)

Abstract:
Based on the first-order kinetics, a hydrolysis dynamics model including the influence of temperature was set up for solid waste in bioreactor landfills. The parameters in the dynamics model were determined by simulation experiments and its reliability was verified. The research shows that a high leachate recirculation rate is favorable to the hydrolysis of solid waste and the rapid stabilization of solid waste in a bioreactor landfill under high temperature, while the leachate recirculation rate should be lowered under low temperature.

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2005 Vol. 18, No. 1