西南交通大学学报

A Compendious Mathematical Model for Precision Analysis in GPS Data Post-Processing

FANDong-ming

2002, 15(3): 1-230.

[Abstract](1592)

Abstract:
A mathematical model of error propagation is derived for transforming the rectangular space coordinates to the geodetic coordinates and further transforming to the Gauss coordinates. Comparedwith the methods available in literature, the proposed method is more compendious and rigorous.

The Load and Crack Width Model for Partially Prestressed Concrete Beams Based on Neural Network

WUDa-hong, ZHAO Ren-da

2002, 15(3): 231-235.

[Abstract](1608)

Abstract:
The initiation and propagation of cracks in concrete structure are very complex and to some extent, and it is difficult to model it in a regularway. Amodel based on neural network, which is good at association and generalization, is proposed to study the relationship between the crackwidth and the applied load in partially prestressed concrete beams. The model is verified by some test results with satisfaction.

The Asynchronous Excitation Model for the Seismic Response Analysis of Long-Span Bridges

ZHAO Can-hui

2002, 15(3): 236-240.

[Abstract](1486)

Abstract:
Based on the two-dimensional coherency function, a asynchronous excitation power spectral density (PSD) model is established, in which the effect of two-dimensional coherency is considered. The relationship between amplitude, phase angels and PSD is obtained using stochastic process. The numerical simulation method for the history of ground motions is proposed. With the proposed method, an acceleration history sample can be generated and used in the seismic response analysis of long-span bridges.

The Principle of Virtual Work for Deformable Bodies and Its Application to Contact Problems

MAOJian-qiang, DING Gui-biao

2002, 15(3): 241-245.

[Abstract](1351)

Abstract:
The theory of virtual work principles of deformable bodies and the technique to derive their expressions are studied and applied to contact problems to build FEM formulas. An infinitesimal element that constitutes a deformable body is taken as a particle, which is constrained elastically by the other particles around it but loses no degree of freedom. Accordingly, the whole deformable body becomes a particle system. The principles of virtual work for deformable bodies can be obtained with facility by taking advantage of the well-known principle of virtual displacement in analytical mechanics. The principles of virtualwork is applied to solve contact problems. Especially, the study focuses on the contact between a bodywith small stiffness and anotherwith very large stiffness, which leads to two special instances:(1) that between a deformable and a rigid bodies; and (2) that containing so-called external contact boundary between a deformable and a fixed rigid bodies. It would be convenient to solve some special contact problems in engineeringwith the method presented in this paper.

The Influence of Boundary Character of Reservoir Bottom on Hydrodynamics in Fluid-Structure Systems

YANQi-xiang, LIUHao-wu, WANG Zhong

2002, 15(3): 246-249.

[Abstract](1434)

Abstract:
The influencing matrix of absorption boundary conditions of reservoir bottom in fluid-structure system is derived, and the dynamic coupling reactions of the dam is calculated with different reflection ratios. The resultshows thatthe dynamic responses ofthe damare related closelytothe characteristics ofthe reservoir bottom. The greater the reflection ratio is, the larger the dynamic responses of the dam and the hydrodynamics of the water in the reservoir are. Therefore, ignoring the absorption of the reservoir bottom will result in unacceptable errors.

A Thermodynamic Dissolution Model of Carbonate Rocks and Its Engineering Geological Significance

XIAOLin-ping, HUANG Si-jing

2002, 15(3): 250-253.

[Abstract](1241)

Abstract:
The dissolution of carbonate rocks is simulated by experiments. The thermodynamic equations are derived to study the dissolution quantitatively under 3 temperature and pressure conditions, namely, 348.15 K and 20 MPa, 373.15 K and 25 MPa, and 403.15 K and 30 MPa. Dolomite is much easier to dissolve and lead to deposition of oil and natural gas than the limestone is. The engineering geologic significance of the study is that the geological conditions should be considered for the location of a newcity, railway, tunnel, and so on, to avoid the risk of geological disasters.

Lateral Dynamics of Bogies with Independent Wheels

HUANG Yun-hua, LIFu, FUMao-hai

2002, 15(3): 254-259.

[Abstract](1589)

Abstract:
The dynamic model of bogies with independent wheels is proposed. The dynamic responses are calculated and compared forbogieswith independentwheels and conventionalwheelsets. Because there is no rotating restraint on an independent wheel, the longitudinal creepage force is very small or even equal to zero, so that the hunting motion is avoided. The study also shows that the friction factors of wheels/tracks affect the centering ability greatly.

Comparison between Vehicle-Track Coupling Dynamic Performances of Railway Vehicles with Two Types of Wheel Profiles

WANGKai-yun, ZHAI Wan-ming, CAI Cheng-biao

2002, 15(3): 260-264.

[Abstract](1601)

Abstract:
With the theory of vehicle-track coupling dynamics and the simulation softwareTTISIM, dynamic performances of vehicles with the cone and the worn profiles, respectively, are calculated and compared in detail. The results showthat the worn profile wheels perform better on curve tracks, while the cone profile wheels have higher critical speed of hunting stability. There is not obvious difference in carbody vibration of vehicles with the two type profiles running on tangent tracks.

Prediction of Fatigue Life of Crane Structures

XIONGLi, LIDan-ke

2002, 15(3): 265-268.

[Abstract](1510)

Abstract:
Based on test data and research achievement available in literature, the fatigue parameters of welded boxes of overhead and gantry cranes are recommended. By using the equations for the stable propagation period of constant amplitude loading fatigue cracks, the fatigue life of the welded box girders of bridge gantry cranes is estimated.

Analysis of Heating Methods for High and Large Building Spaces

CAIDe-yuan, XUZhi-hao

2002, 15(3): 269-272.

[Abstract](1143)

Abstract:
Based on the theoryof heattransfer, the virtues and shortcomings of different heatingmethods for high and large building spaces are analyzed. The numerical and experimental results of the laminar heating by horizontal hot air curtains are presented in detail. The results showthatmore comfortable but less energy consumption can be obtained with the laminar heating by horizontal hot air curtains than the conventional radiation heating in high and large building spaces.

Simulation of 3D Motion of Robots

LIGang-jun, CHEN Yong

2002, 15(3): 273-276.

[Abstract](1517)

Abstract:
A design instance of a 3D motion simulation system of robot manipulators is introduced and analyzed. The effective method ofmotion simulationwithOpenGLfor a robot is presented. The construction ofkinetic model and the real display of the motion are analyzed emphatically. The main features of the system and the future application of OpenGL in robotic simulation are discussed.

A Novel Zero-Voltage Soft-Switching Arc Welding Inverter Based on Peak-Current Mode

DUGui-ping, HUANG Shi-sheng, WANG Zhen-min

2002, 15(3): 277-280.

[Abstract](1218)

Abstract:
To overcome the shortcomings of conventional arc welding inverters, a new soft-switching topology, together with the phase-shifted soft-switching and peak current control technology, is used to develop a newsoft-switching arcwelding inverter. The testresults showthatthe full range soft-switching and the functions of auto-correction and current limiting are realized for the inverter, solving the problem of magnetic bias of the power transformer.

Design of Multi-rate Optimal Regulator for an Inverted Pendulum

ZHANG You-gang, SUNZhong-guo, XIAOJian

2002, 15(3): 281-285.

[Abstract](1576)

Abstract:
A time-invariant, single-rate design approach for multi-rate optimal regulator is presented. The design of a multi-rate system is converted to a single-rate system design problem by using‘lifting’ technique. As an example, a typical problem in the researchof control, the control of an inverted pendulum on a cart is studied. The feasibility of the proposed method is verified by the simulation results.

A New Algorithm for Hard-Decision Parallel Interference Cancellation

LIUWei, ZHUChang-qian

2002, 15(3): 286-289.

[Abstract](1000)

Abstract:
Multi-access interference (MAI) is the major factor degradingthe CDMAsystemperformance and capacity. According to the characteristics ofMAI in CDMA systems, a multi-user detector is designed by a newhard-decision parallel decision algorithmforMAI cancellation. Analysis and simulation results showthat this detector performs better and has larger capacity to restrain near-far impact than the conventional ones, and hence has good potential for practical application.

Application of Watershed Algorithm to Cell Image Segmentation

WANGJin-tao, LIUWen-yao, LUShuo

2002, 15(3): 290-294.

[Abstract](1341)

Abstract:
To overcome the difficulty caused by the overlapping of cells in the image analysis for cancer diagnosis, a new cell image analysis method is proposed based on watershed algorithm to separate the clustering cells into single ones. Firstly, a distance map is produced to determine the number of seeds from the clustering cells based on iterative erosion. Then, the ultra-erosion aggregates are taken as the seeds to separate the cells. Finally, the images are grown from the seed regions until all of the image pixels except the boundaries of convex have been assimilated. The design and implementation of the algorithm and experimental results are presented.

Application of Proxy Signature to Smart Card Authentication

LIUPei-shun, HEDa-ke

2002, 15(3): 295-298.

[Abstract](1555)

Abstract:
Smart cards are ideal key storage devices, but their public key operations are inefficient because of their limited resources. To solve this problem, a scheme based on proxy signature is proposed according to the characteristics of smart cards. The experiment results show that the proposed scheme has higher efficiency than other ones in literature while guaranteeing the safety of the key on a smart card.

An Investigation on Layout of Overtaking Stations for Express Trains along Existing Double Track Railways

ZHUJian-mei, YANHai-feng, ZHOUYong

2002, 15(3): 299-304.

[Abstract](1417)

Abstract:
Based on the analysis of the structure of train diagrams, the conditions for specific overtaking modes to take place are discussed. The carrying capacity and the speed of passenger trains are analyzed on condition that express trains are to be put intooperation on the existing double track railways and the number of tracks in intermediate stations to be unchanged. A probability model for layout of overtaking stations for express trains is proposed. Simulation is conducted by taking the Beijing-Shanghai and Beijing-Guangzhou railways for example. Some principle for layout of overtaking stations for express trains along existing double track railways are suggested.

The Minimal Winning Coalition of Enterprises in Competition

ZHANG Shu-yi, LIXiao-long, WUZhen-ye

2002, 15(3): 305-308.

[Abstract](1256)

Abstract:
The minimalwinning coalition,S, of enterprises in competition ofthe setVsis proved, inwhich the revenue of the members who do not belong toSis equal to 0.Vsis analyzed with some examples discussed in the aspects of the size of strategic coalitions, allocation of benefits among the members, the opportunistic behaviors ofthe members and the compensation tothosewho havewithdrawn. Coalitions do not necessarily mean monopoly. Redistribution of available resources not only benefits enterprises, but improves the social welfare

Analysis of Fluctuations of Economic Development of China

CHENGXiao-kang, DUWen

2002, 15(3): 309-313.

[Abstract](1192)

Abstract:
The Mexican Hatwavelet is applied to analyzing the fluctuations of economic development in P. R. China since its foundation in 1949. The increasingrate ofGDP is analyzedwiththeMexicanHatwavelet at a range of time scales, and the causes of the fluctuations is discussed based on macroeconomic theory in view of government policies, investment and consumers’behaviors. China’s economy shows different cycles at different time scales, and it is affected by the government policies, important political events, investment and consumer’s behaviors.

Analysis of Multinational Strategy Alliances with Game Theory

YAOHong-xin, WUZhen-ye

2002, 15(3): 314-318.

[Abstract](1158)

Abstract:
Multinational strategy alliances avoid competitions of direct export by supply and distribution agreements. They do not share stocks but keep a competitive relation in cooperation. The forming processes of combative export equilibriumand cooperative alliance equilibriumofmultinational enterprises are analyzed dynamicallywith game theory. Two kinds of influences of equilibrium conditions on the variation of market prices, output level and social welfare are clarified. The preconditions for an international alliance to be an effective economic organization are deduced.

Analysis of the Policies for Right Offering of Corporations with Game Theory

WANGXing-yu

2002, 15(3): 319-322.

[Abstract](1291)

Abstract:
Based on the analysis of the expected income discontinuity curves of corporations with game theory, which are commonly believed to be caused by the supervision policies, the deficiencies of the policies are pointed out. The policies are preferential ones, resulting in pooling equilibriumof the financial reports from the corporations, and further causing inefficiency of stock market. The ways to solve this problem are to relax and eventually call off the requirement of that the net asset yield is not less than 6% that is a criterion to decide if a corporation canget a rightofferingopportunity. As a temporarymeasure, the right offering of a corporationmay be decided accordingto its net assets yield aswell as some other financial indexes.

Analysis of the Causes of Project Contract Claims Based on Multiattribute Utility Function

LIXiao-long, WUZhen-ye, LILiang

2002, 15(3): 323-327.

[Abstract](1197)

Abstract:
The investment, schedule and quality of a project are taken as variables to construct the multiattribute utility functions of the two sides of a contract. The relationship between the utility values of the two sides and at the counterpoise point and the factors affecting the relationship are studied through the analysis of the Nash solution to their game playing. The causes of claims are analyzed according to the changes of the utility counterpoise points. The study is helpful to explain the phenomenon‘biddingwith low price, profiting by claim’

Extended Gauss Model and Its Simulated Annealing Algorithm

ZHAO Zheng-jia, GUO Yao-huang

2002, 15(3): 328-332.

[Abstract](1691)

Abstract:
The method for global optimization by random artificial neural networks (AN2) is studied. The Gauss model is modified to an extended Gauss model, which can be used to obtain the global optimum. With the simulated annealing algorithm being taken into consideration, the simulated algorithm for the extended Gauss model is proposed. Simulation shows that the extended Gauss model has the best comprehensive behavior, the extended Gauss model running with the simulated algorithm gives the best global performance with much longer operation time than other two, and the extendedHopfield model is the worst among them.

A Sort of Partial Order Relation in Independent Systems

ZHANGAi-li, LIUXiu-feng

2002, 15(3): 333-337.

[Abstract](1027)

Abstract:
The concept of incompatible group in independent systems is proposed. A sort of partial order relation is set up in independent systems , which do not contain any incompatible group. The characteristic of the concept is discussed. An independent system is divided into cliques according to the proposed partial order relation. The independence of a subset depends only on the cardinal number of intersection sets between itself and every clique.

Fuzzy Multi-objective Optimization Based on Neural Networks

GUANQin-chuan

2002, 15(3): 338-342.

[Abstract](1447)

Abstract:
Based on the functional link network, a new algorithm is proposed to solve the multi-objective optimization problems in engineering structures. In the algorithm, the degress of designer’s satisfaction are regarded as a sample set, and neural network is used to replace the traditional membership functions. The membership functions can be well described with the new method. This method is more flexible than the traditional ones in solving multi-objective optimization problems.

The Topological Structure of Lattice Implication Algebras

WANG Wei, XUYang, QINKe-yun

2002, 15(3): 343-346.

[Abstract](1315)

Abstract:
The concept of week filters of lattice implication algebra and their properties and structures are discussed. It is proved that all week filters of lattice implication algebra form a topological structure and the implication isomorphism between two lattice implication algebras is the mapping of their topological structures.

Search for 3 TeV Gamma-Ray Bursts Coincident with the BASTE Experiment by Using the Data of Tibet HD Air Shower Array

FENG Zhen-yong

2002, 15(3): 347-351.

[Abstract](1252)

Abstract:
A search for 3 TeV Gamma-ray bursts (GRBs) coincidentwith the BASTE experimentwas done by using the data of the Tibet HD air shower array. 15 GRBs in the 4B BASTE catalog were searched, whichwere obtained in March, 1998, and within the effective viewing sky of the Tibet HD array. The so- called cluster method was adopted in the analysis. No convincing signal was detected fromthe direction the BASTE GRBs. The result supports the cosmological model of gamma-ray bursts.

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2002 Vol. 15, No. 3