西南交通大学学报

Effect Analysis of Track Stiffness on Dynamic Characteristics of Wheel-Rail System and Its Dynamic Optimization

LIUXue-yi

2004, 17(1): 1-4.

[Abstract](1553)

Abstract:
The effects of track stiffness on track dynamic characteristicswere investigated by the wheel-rail system dynamic analysis in frequency domain. The concepts of sensitivity coefficients of track dynamic parameters to track stiffness were put forward and defined. The method of dynamic optimization was proposed for the global track stiffness and the ratioof fasteningstiffness to ballaststiffness on the basis ofthe characteristics of the sensitivity coefficients. As an example, this method was applied to research track stiffness in a high-speed railway in China. The result shows that the optimum global track stiffness ranges from 62 to 86.9 kN/mm and the optimum ratio of fastening stiffness to ballast stiffness is about 0.5.

Sensitivity Analysis of Elastoplastic Time-History Reliability of Story-Drift Capacity of Aseismatic RC Frames

ZHANGXin-pei, GE Yan, CHENShi-chao

2004, 17(1): 6-9.

[Abstract](1606)

Abstract:
An algorithm was proposed to analyze the elastoplastic time-history reliability of lateral deformation capacity of aseismatic reinforced concrete(RC) structures on the basis of the improved JC method for calculating the static reliability of structures, the Wilson-θmethod and the member-storymodel. And this algorithm was used for the sensitivity analysis of structural parameters, as random variables, influencing the elastoplastic time-history reliabilityof the story-drift capacityof an aseismatic RC frame. The research result shows that in all the structural parameters, the elastic modulus of concrete and the sectional sizes of beams and columns of an aseismatic RC frame have the greatest effect on its time-history reliability, while as far as some structural parameter is concerned, its effecton the time-historyreliability is changing in the whole process of an earthquake

Experimental Research on Confluence between Debris Flow and Main River

CHENChun-guang, YAOLing-kan, YANG Qing-hua

2004, 17(1): 10-14.

[Abstract](1522)

Abstract:
Model similarity-rules for confluence between a debris flow and the main river were analyzed, and a series ofmodel experimentswere performed to investigate the regularityof confluence between a debris flowand the main river. The experimental result shows that the movement patterns of a debris flow are different in the intersection region for different relationships between the branch and the main river and can be divided the submerging flowand the stratification flow. In the submerging flow, the velocityof the debris flowhead, submerging intowater, decreases approximately linearly, the changes in its height and length are very small, and there is a linear relationship between the width and the length. All these are quite different from a density current. Furthermore, whenwater flows into the branch, the debris flowheadwill be broken bywater, resulting in the sedimentation of sand and stone. Under that condition, the debris flow entering into the river becomes a stratiform flow.

Modified Mesri s Creep Model for Soils in Sliding Zone of Xietan Landslide in the Three Gorges

WANG Chen, LIUHao-wu, XUQiang

2004, 17(1): 15-19.

[Abstract](1582)

Abstract:
In orderto provide the basementof a further numerical analysis, the drained triaxial compression creep tests with a constant stress were carried out for soils in the sliding zone of Xietan landslide in the Three Gorges. Based on these tests, a shear stress-strain-time function, namely, Mesri s creep model, in which a hyperbolic linewas adopted for describing the shear stress-strain behaviour and a power function for the strain-time behaviour, was given. A modified Mesri s shear stress-strain-time model was proposed. In this model, the strain-time behavior of the soilswas simulated by subsection. Through contrast of computed curvesbased on the two models and test data, the result shows that the modified Mesri s model has an advantage over the Mesri s model in the simulation capability for creep behaviours of clay.

Model Experiment System for High-Speed Trains and Analysis of Its Similarity

WANG Ying-xue, LUOJian-jun, LILun-gui, JUJuan

2004, 17(1): 20-24.

[Abstract](1785)

Abstract:
To solve the aerodynamic problems resulted from high-speed trains when they pass through a tunnel, a model experiment system for high-speed trains was set up on the basis of analyzing the relative present experiment systems(methods) at home and abroad, and its similarity rules were derived. In this system, compressed air is used to impel a model train, and the speed of this train speed can reach 70 m/s. The compression wave caused by high-speed trainswhen they pass through a tunnelwas measured using this experimental system. Comparison between experimental and numeral simulation results shows that the similarity rules are correct.

Accuracy Estimation of Lateral Piercing for GPS Tunnel Control Network

GULi-ya

2004, 17(1): 25-29.

[Abstract](1454)

Abstract:
Based on the observations of the baseline vector measured by GPS technology, a formula of accuracy estimation of lateral piercing for GPS tunnel control networks was deduced. A practical example verifies that the estimated results obtained by ignoring the covariance of the observations are very close to those by strict calculation taking the covariance into account. When estimated by inherent standard deviations of GPS receivers, the accuracy of lateral piercing can also meet the needs of a horizontal tunnel control network. This method of accuracy estimation of lateral piercing can adapt to the design of a GPS control network before tunnel construction surveying. The research result shows that the key factor to affect the lateral piercing accuracy for a tunnel is the relative accuracy of baseline azimuth surveying at the two entrances of the tunnel.

Research on Benefit Allocation among Cooperative Partners in Supply Chain

YEHuai-zhen, HUYi-jie

2004, 17(1): 30-33.

[Abstract](1240)

Abstract:
The four principles for benefit allocation among cooperative partners in a supply chain were proposed,i. e.more pay for more work, venture compensation, effectiveness maximization and comprehensive optimum. Three models of benefit allocationwere set up respectively based on the first three principles, and three schemes of benefit allocation were designed for different resources input, possible venture and effectiveness product. To take the importance of the three principles under the different conditions in benefit allocation into account, an improved colony barycenter model was adopted, and the concept of essentiality modulus was introduced. At last, a calculation example was given to explain the application of the improved colony barycenter model in benefit allocation among cooperative partners in a supply chain.

Decision-Making Model for Outsourcing in Supply Chain

MAZu-jun

2004, 17(1): 34-37.

[Abstract](1344)

Abstract:
In order to meet the demand of outsourcing decision-making in a supply chain, an outsourcing model was proposed, and the capacity investment levels and production decisions of an upstream firm (supplier) and a downstreammember(buyer) were analyzed under the condition of their making decisions separately. In addition, the patterns of outsourcing based on a price-focused contractwere discussed. Based on the above, a two-stage dynamic game model for two members in a supply chain was set up, and it was proven that this game model characterizes the sub-game perfect Nash equilibrium.

Optimum Decision-Making Model and Arithmetic Analyzing of Delivery System Based on VMI

LI Zong-ping, YUANQing-da

2004, 17(1): 38-41.

[Abstract](1608)

Abstract:
To implement the integrated supply chain and VMI (Vendor-managed inventory), an optimization model was proposed by taking both the delivery expenses and the inventory expenses of customers into account. Under the condition that vehicles for delivery have been dispatched for specific customers as the preliminary plan, the model can be divided into two submodels of the inventory allocation and traveling salesman problems to reduce the difficulty of solving the model. The submodels can be solved with some available algorithms and integrated into the original model.

Mathematical Model and Analysis of Runway Landing Capacity

YUJiang, PUYun

2004, 17(1): 42-46.

[Abstract](1650)

Abstract:
It is believed that most of parameters influencing the interarrival time of landing are random variables, so the setting up of a runway landing capacity model must be based on probability theory. From the viewpoint of a controller, a probability model of runway landing capacitywas proposed. In this model, the effects of approach speed, position uncertainty, wind speed, runway occupation time and traffic mix on runway landing capacitywere sufficiently considered and actual statistic data were its basis. In addition, a calculation example was given. The calculated result shows that runway occupation time and separation time standard influence greatly runway landing capacity and the effects of the other parameters are relatively small.

Analyses of Valuation of Market Information and Its Influential Factors

ZHANG Yong-peng, WEI Ya-qin, SHI Yu-ling

2004, 17(1): 47-50.

[Abstract](1511)

Abstract:
Based on a game model, the relationship between the valuation of market information and its influential factorswas discussed. The research shows thatmarket information is ofgreatervaluationwhen the variation of market demands, the substitutabitity of products, or the scale of enterprises, is large.

Empirical Research on Relationship Between Customer-Orientation Behavior and Competitive Superiority of Enterprises

LIUBo, TANDe-qing, YE Yong

2004, 17(1): 51-55.

[Abstract](982)

Abstract:
In order to raise the competitive superiority of enterprises, the cross-sectional data of manufacture and service industries in China were used to analyze the effects of the customer-orientation behaviors of enterprises on their competitive superiority. The research result shows that the customer- orientation behaviors of an enterprise influence its competitive superiority obtaining directly and significantly, and activelyhandling customer complaints has a positive effecton the competitive superiorityof the enterprise.

Team Incentive Model of Nonprofit Organizations

MAO Gang, ZHULian, LIKai-rong, GUO Yao-huang

2004, 17(1): 56-60.

[Abstract](1127)

Abstract:
Based on Holmstrom’s team theory, a team incentive model for nonprofit organizations was established by considering a variable of public utility and ignoring environmental effects. Itwas proved that there is no Nash equilibrium of the game induced by allocation schemes under the conditions of budget balance and some regulatory constraints. The incentive problem of a nonprofit organizational team can be solved and an allocation scheme can be devised by introducing a principal as the budget-breaker into the team.

Chaotic Self-motion of Redundant Robot in Null Space

LILi, LIKai-fu, CHEN Yong

2004, 17(1): 61-63.

[Abstract](1428)

Abstract:
Based on the control theoryof feedback linearization, the zero dynamics equation for a planar3R rigid redundant robotwas derived. Using Poincare maps and Lyapunov exponents, the motion state(regular or chaotic motion) of the redundant robotwas numerically simulated, and the relationship between its self- motion state and its vectors in the null space was obtained. The research result shows that the chaotic self- motion of a redundant robot is influenced by the initial conditions and has a direct relationwith its victors in the null space.

Efficient Algorithm for Line Clipping against General Polygon

ZHAO Ping, FENG Chun, LIBo-lin

2004, 17(1): 64-68.

[Abstract](1323)

Abstract:
Based on the analysis of advantages and disadvantages of the existing algorithms, a new algorithm for line clippingwas proposed. This algorithm is composed of three steps: the intersection points of a line to be clipped and a general polygon are calculated, the line is cut into several sub-lines based on the intersection points, and whether these sub-line are cut or not is decided in light of their central points. The algorithm can deal with all kinds of situations easily and correctly.

Design of Continuous Wheel/Rail Force Measurement System

PANZhou-ping, ZHANGLi-min

2004, 17(1): 69-72.

[Abstract](1459)

Abstract:
Based on the characteristic of rails underthe action ofwheels of a train, a continuouswheel/rail force measurement systemwas designed, and the parameters in the formulae for calculating the vertical and horizontal forces were determined by simulation. The system was evaluated on an experimental rail line, showing a good ability to measure the vertical and horizontal forces.

Experimental Research on Properties of Existent Rubber Draft Gear for Meter-Gage Railway Freight Car

LI Yang-hui, ZHAO Yong-xiang, SUN Ya-fang

2004, 17(1): 73-76.

[Abstract](1408)

Abstract:
To find out the causes for the poor behaviors of the existing rubber draft gears and develop new rubber draft gears, the properties of the existing rubber draft gears of meter-gage railway freight cars were investigated experimentally. The experimental results reveal thathigh compressionmodulus and unreasonable structure design are two essential reasons for the poor behaviors of the rubber draft gears. As a result, the draft gears are high in impacting force, capacity and mass, low in allowance travel and energy absorption ratio, and short in service life. In addition, the cost of the draft gears is high in manufacturing and maintaining. Therefore, the existing draft gears are not suggested for meter-gage railway freight cars.

Algorithm of Optimal Active Structural Control Based on Precise Integration

LIJin-qiao, YUJian-hua

2004, 17(1): 77-81.

[Abstract](1301)

Abstract:
To raise the calculation precision of active structural control, the closed-loop and closed-open- loop control algorithms for instantaneous structural optimizationwere improved based on the active structural control strategy and the precise integration method (PIM). Different from the traditional solutions of structural control equations, it is not required for this improved algorithm to solve the characteristic vector and the eigenvalues of a dynamic state matrix. As a result, the precision of instantaneous structural control can be raised. As an example, this algorithm was used for the control simulation of two structures. The results showthat the algorithm is convergent and not sensitive to time-step, and its calculation precision can be controlled easily.

Dynamical Characteristics Analysis of Core Barrel of Nuclear Reactors in Air and Still Water

LULi, YANG Yi-ren, JINJian-ming

2004, 17(1): 82-85.

[Abstract](1874)

Abstract:
By means of the fliud-structure interaction, the dynamical characteristics of the core barrel of nuclear reactors in air and in stillwaterwere investigated using programANSYS. Asolid modelwas used to simulate the core barrel, the fluid structurewas simulated bythe elementof fluid80, thus the effectof added mass of still water on the dynamical characteristics of the core barrel was included. The research results showthat both in air and in water, the first several order nature frequencies of the core barrel are formed frombeam and shell frequencies under its different boundary conditions, and circumferential rotation and axial flexible frequencies are its higher order frequencies. Moreover, the vibrational frequencies of the core barrel in still water are much lower than its corresponding order frequencies in air.

Generalized Association Rule Base and Its Mining Algorithm

LITian-rui, YANGNing, MAJun

2004, 17(1): 86-89.

[Abstract](1396)

Abstract:
To solve the problemthatthe existing algorithms ofmining association rules result in a numberof rules, upper closed set of an item set and generalized association rule base were defined. And some important propositions were obtained,e.g.the upper closed set of an item set exists uniquely and is the item set. From these propositions, the generalized association rule base of a transaction database was proposed. It contains the information of all the association rules in the database and the rules have a uniform structure. As a result, the number of rules can be reduced as many as possible. In addition, a mining algorithm for generalized association rule bases was proposed and its validation was proven using an example.

Syntactic System of Lattice-Valued Propositional Logic Based on Finite Lattice Implication Algebra

MAJun, GAO Ya, QINKe-yun, XUYang

2004, 17(1): 90-94.

[Abstract](1315)

Abstract:
By taking finite lattice implication algebra as a truth-value field, a syntactic system of lattice- valued propositional logic based on finite lattice implication algebra was proposed. The basic definitions of syntactic implies, proof and consistency of the system on levelAwere given axiomatically. Finally, the soundness theorem, consistency theorem, weak complete theorem andweak deduction theoremof the system were proved.

Reduced-Order Method for Connection Matrix in Network with Voting Systems

CHENG Shi-juan, LUWei, HEPing

2004, 17(1): 95-98.

[Abstract](1322)

Abstract:
To solve the problem that the order of a connection matrix is greatly increased because a large number of repeated nodes and links are resulted in when a network with voting systems is changed into a network graph, a reduced-order method was proposed. In this method, the connection matrix are divided into block matrixes on the basis of its characteristics, so a voting sub-system is corresponding to a block matrix, and the block matrix corresponding to the voting system is operated independently by defining and using twomatrixoperators. The calculated resultshows thatthismethod can reduce the orderof a connection matrix greatly.

Video Error Concealment Technique Based on Side Matching

PENG Qiang, ZHUChang-qian

2004, 17(1): 99-103.

[Abstract](1225)

Abstract:
A newerror concealmentmethod using pre-concealment process (PREP) and search concealment (SC ) was proposed. This method uses surrounding motion vectors (MV) as many as possible by pre- processingadjacent MBs(Macroblock, MB), and then finds the best MV s by performing an additional search process. Simulation results based on JM1.4 CODEC of JVT (Joint Video Team) show that both PREP and SC significantly improve the reconstruction of video quality and much better results can be achieved by combining the newtechnique with no-waiting ARQ (NWARQ) technique.

New Class of Spreading Sequences for Quasi-synchronous CDMA Systems

HUFei, WENHong, CHENHua-wei

2004, 17(1): 104-107.

[Abstract](1167)

Abstract:
Based on the generalized Chirp-like sequences, a new class of spreading sequences was constructed with the help of the product technique and its correlation properties were discussed. The research results show that among the proposed sequences, there is a subclass of sequences with zero correlation zonewhich can be used in quasi-synchronous CDMAsystems; a complex spreading sequence can be constructed only through complex number summing and module operating when the complex number generated in the generalized Chirp-like sequences is taken as a complex unit root.

Optimization of Compensation Length for Multi-period Postcompensation DM Systems

XIONGJie, LUO Bin, PANWei, ZHUXi-ping

2004, 17(1): 108-111.

[Abstract](1310)

Abstract:
To obtain an optimumdispersionmanagement (DM) scheme for 40 Gb/s long-haul multi-period postcompensation systems, compensation lengthswere studied by simulation. The results showthatthe pulse width is inerratic alongthe longfiber, the optimumlength for a long-haul multi-period system is shorterthan the maximum compressed compensation length for a single-period system, and the optimum length is lengthened as an increase in the peak power of the pulses.

Non-linear Noise Canceller Based on Additive-Multiplicative Fuzzy Neural Network

ZHAIDong-hai, LILi

2004, 17(1): 112-116.

[Abstract](1714)

Abstract:
A novel nonlinear noise canceller based on additive-multiplicative fuzzy neural network (AMFNN) was proposed, and its model, learning algorithm and universal approximationwere discussed. In the cancellation process, AMFNN is used to approximate the noises, and the noises are cancelled to recover the useful signals. The new canceller has the advantages of neural networks, such as the ability of parallel distributed information processing, fault-tolerance and robustness, and is easy to use as a noise canceller.

Globally Asymptotic Stability of Neural Networks with Reaction-Diffusion

ZHENG Wei-fan, ZHANGJi-ye

2004, 17(1): 117-121.

[Abstract](1563)

Abstract:
Even type Lyapunov functions were constructed based on M-matrix theory to study the globally asymptotic stability of Hopfield networks with reaction-diffusion. These networks are generalized without assuming the boundedness, monotonicity and differenciability of the activate functions. The conditions were obtained for globally asymptotic stability of the generalized Hopfield networks, where the interconnection matrices are symmetric or non-asymmetric and the neural activate functions are non-monotonic.

Linear Theory of Relative Traveling-Wave Tube Filled with Plasma

WANG Yun-xiu, YANG Zi-qiang, LIANG Zheng

2004, 17(1): 121-125.

[Abstract](1320)

Abstract:
Based on the assumption that the guide magnetic field is infinite, the dispersion equation for a ripple slow-wave structure filled with plasmas was derived. Through a numerical simulation, the effects of plasma densitywere analyzed on the dispersion property when there is no an electron beam in a slow-wave structure filled with plasmas and on the frequency and gainwhen there is an electron beam in the slow-wave structure. The research result shows thatwith the raisingof plasma density, the operation frequencyofTM01 module increases and the gain of a slow-wave structure filled with plasmas decreases continuously.

Approximation Capability of Fuzzy System Based on Multi-resolution Analysis

WANGHui, XIAOJian

2004, 17(1): 126-130.

[Abstract](1164)

Abstract:
A novel T-S fuzzy system based on multi-resolution analysis was presented. The system was constructed based on multi-resolution analysis theory and localization in time-frequency domains. B-spline functions were taken as scale functions to make use of their compact supporting and multi-resolution characteristics. The approximation property of the system was analyzed theoretically, and the results show that the function set of the system is dense in normed space,LP(E),i.e.with universal approximation property.

In SituSynthesis of TiB2-TiCxCeramic Matrix Composites by Hot Isostatic Pressing

JIANGJun, ZHUDe-gui, WANGLiang-hui

2004, 17(1): 131-134.

[Abstract](1117)

Abstract:
TiB2-TiC ceramic matrix composites were fabricated byin situsynthesis under hot isostatic pressing (HIP) with 3TiH2-B4C and 11TiH2-3B4C being the rawmaterials, respectively. The XRD analysis indicates that the samples synthesized from3TiH2-B4C haveTiB2andTiC phases, while those from11TiH2- 3B4C have notonlyTiB2andTiC phases, but alsoTi3B4phase. SEMresults showthatthe microstructures of the composites synthesized from 3TiH2-B4C are not well-distributed, and there are some platelet grains in some zones, while those from 11TiH2-3B4C are fine with many regular-platelet grains. TiB2-TiCxceramic matrix composites obtained from11TiH2-3B4Chave bettermechanical properties than those from3TiH2-B4C.

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2004 Vol. 17, No. 1