西南交通大学学报

Genetic Simulated Annealing Algorithm for Time-History Reliability of Aseismatic Structures

ZHANGXin-pei, DONGNa

2004, 17(4): 419-422.

[Abstract](1583)

Abstract:
To analyze the time-history reliability of aseismatic structures, an algorithmbased on the genetic simulated annealing and time-history methods was proposed on the basis of the characteristic of structural performance functions for the time-history reliability of aseismatic structures,i. e.they are implicit functionswith strong non-linearity. This algorithm can reflect the randomness of structural parameters and earthquake motions and the effects of an earthquake action and static loads. Furthermore, time-history reliability index of aseismatic structures at any time in the process of an earthquake can be got by using the algorithm. As an example, the time-history reliability of story-drift capacity for a three-story reinforced concrete (RC) frame respectively under frequent and strong earthquakes was analyzed using the algorithm and the Monte Carlo method, and the result shows the effectiveness of the algorithm.

Finite Element Method for Tunnel with Prefabricated Lining

MAOJian-qiang

2004, 17(4): 423-427.

[Abstract](1562)

Abstract:
The interaction between the lining and surrounding rock of a tunnel was taken as a contact problem. On the basis of the principle of virtual work for deformable body, a finite element method for the contact problem was proposed and the procedure for solving an elasto-plastic contact problem was given, especially focusing on the technique to deal with the penetrating contact status,i.e.two contact bodies penetrate each other. In the end, two illustrated examples—one is two nesting thick cylinders subjected to internal pressure and the other is a shield-driven metro tunnel, were solved with this method successfully.

Full-Scale Experiment on Spherical Cast-Steel Joint of Long-Span Reticulated Shells

WEIXing, LIJun, QIANG Shi-zhong

2004, 17(4): 428-432.

[Abstract](1239)

Abstract:
Through a full-scale experiment on the spherical cast-steel joint of reticulated shells of the Chongqing Olympic Stadium, stresses on the cast-steel joint were obtained. By combining the full-scale experimentwith a theoretical analysis, static behaviors of the cast-steel joint and the pathway of stress transfer were analyzed, and the differences between distributions of stresses on pipe shaft and spherical joint surfacewere pointed out. From the stress distribution obtained through the experiment, the security and load-bearing capacity of the spherical cast-steel joint were evaluated based on the Mises strength criterion. In addition, the ratio of stresses on pipe shaft and pipe foot, as amain factortomeasure the degree of stress concentration, was also analyzed. It was put forward that the distribution of stresses on a large spherical cast-steel joint can be improved by controlling the ratio of stresses.

Reason for Resulting in High Direct Shearing Strength and Improvement of Loading Uni

2004, 17(4): 433-436.

[Abstract](1112)

Abstract:
Direct and triaxial shearing tests were carried out for deuterogenic adamic earth, silty clay and completelyweathered mudstone, and the experimental results were analyzed. The result shows that shear strength of rock or soil, cohesive force and internal friction angle, obtained through a direct shearing test is markedly higher than that through a triaxial shearing test. The reason for this phenomenon is that normal force in directshearingtests is notusuallyvertical tothe shearforce (shearsurface) to lead tothe change in stress state in samples, as a result, higher shearing strength than triaxial shearing strength is obtained. Finally, an improved measure for the loading unitwas proposed based on the principle of force equilibrium, i.e.loading at its two ends instead of one end.

Simulation of Surface Crack Propagation in Asphalt Pavements and Analysis of Its influential Factors

MAO Cheng, QIUYan-jun, LI Yun-peng

2004, 17(4): 437-441.

[Abstract](1823)

Abstract:
By using the finite element method (FEM) based on theory of linear elastic fracture mechanics, stress intensity factor and crack initiation angle were calculated for surface cracks in asphalt concrete (AC) pavements with three different crack depths under five load cases. Top-down propagation path in AC pavements was simulated and the effects of pavement structure and temperature on the surface crack propagationwere analyzed. The analytical results show that crack propagation is obviously influenced by temperature, thickness of pavement structure and elastic modulus of AC, and the degree of influence increases with the increase of surface crack depth.

Numerical Simulation of Unsteady Three-Dimensional Flow Induced by High-Speed Train Entering Tunnel with Shaft

LUOJian-jun, GAO Bo, WANG Ying-xue, ZHAO Wen-cheng

2004, 17(4): 442-446.

[Abstract](1643)

Abstract:
To decrease the effect of compression wave, the numerical simulation of a three-dimensional viscous flow induced by a high-speed train entering tunnels with a shaft was made. In the simulation, the Navier-Stokes equations, describing three-dimensional viscous, compressible, isentropic and nonstationary flows, were taken as the control equations, the cell-centered finite volume scheme for numerical integration of the Navier-Stokes equations was used for space discretization, and the preconditioned second-order accurate backward difference was adopted in time discretization. In addition, the walls and floor of a tunnel were described with wall functions. The calculated result agrees with the oversea experimental one.The research shows that the shaft can decrease air pressure in tunnels, and its section area and position have a great effect on the pressure.

Theoretical Investigation of Compression Wave Induced by High-Speed Train Entering Tunne

ZHAO Wen-cheng, GAO Bo, WANG Ying-xue, JUJua

2004, 17(4): 447-450.

[Abstract](1761)

Abstract:
The complex pressure field resulted from a high-speed train entering a tunnel was investigated based on the theory of aerodynamic sound. In light of actual conditions, the Ffowcs Williams-Hawkings (FW-H) equation was simplified to save calculation resource and calculation time. The Galilean transformation was applied to the simplified equation to make a surface function related to only coordinates. Then, by applying the Fourier transform the problem was transformed from the time domain into the frequency domain. Finally, the compression wave profile was determined by virtue of solving the Ffowcs Williams-Hawkings equation with the help of the Green function methods, according with the present experimental result.

Railway Automatic Blocking Transmission Lines Fault Detection Model

HE Zheng-you, WANG Zhi-bing

2004, 17(4): 451-455.

[Abstract](1730)

Abstract:
The characteristic for short circuit and earth fault of 10 kV railway power transmission lines for automatic block systemswas analyzed, and a fault detection modelwas built. Simulation results showthat it is feasible to detect phase to phase short circuit and single phase earth fault and determine the location ofthe faults with the proposed model.

Location and Speed Detection System for High-Speed Maglev Vehicle

GUOXiao-zhou, WANG Ying, WANG Shi-xiong

2004, 17(4): 455-459.

[Abstract](1470)

Abstract:
To detect the location and speed of high-speed maglev (magnetically levitated) vehicles, a location and speed detecting scheme was proposed. In this scheme, the tooth-and-slots of the LSM (linear synchronous motor) and the location reference leaves beside the track are detected as the relative and absolute location signals, respectively. These signals are compared each other to eliminate the measuring errors. The experiments on the test bench that contains the same long stator as the LSM used in Shanghai high-speed maglev line showthat the proposed scheme is feasible

Calculation of Induction Electromotive Force of Linear Generator of High-Speed Maglev Train

WULi-hong, ZHANGKun-lun, LUO Fan

2004, 17(4): 460-464.

[Abstract](1417)

Abstract:
To supply power for the appliances in high-speed EMS-maglev (electromagnetic suspension- magnetically levitated) vehicles, the position functions of self and mutual inductance in the linear generator were derived. The general formula for the electromotive force of the long stator linear generator and the position functions were derived by calculating the parameters with finite element method and analyzing the working conditions of the linear generator windings, long-stator linear synchronous motor windings and magnetic levitatingwindings. The calculated errors comparedwith the experimental results are less than 7% when the vehicle runs at 100 and 150 km/h.

Dynamic Characteristics of Electromagnetic Levitation Systems

ZHAO Chun-fa, ZHAI Wan-min

2004, 17(4): 464-468.

[Abstract](1642)

Abstract:
The suspension stiffness and damping of an actively controlled electromagnetic suspension system were analyzed theoretically and numerically. The suspension unit consisting of single magnet and series suspension controller was taken as the object for analysis. The analytical results show that the suspension stiffness is positively proportional to the feedback coefficient of airgap and the suspension damping is positively proportional to the airgap derivative. Resonance may occur if any two of the characteristic frequencies of the secondary suspension, the guideway and the control system are close to each other.

Dynamic Analysis of Swing Movable Teeth Driv

WANG Shu-ying, XULi-ju, LIANG Shang-ming

2004, 17(4): 472-475.

[Abstract](1430)

Abstract:
The forces on a single movable tooth were analyzed and the result was taken as the basis for calculating the forces acting on movable teeth of a single set and double sets. Deformation-coordination equations were derived using displacement method and kinetic-static analysis, and the equations were used to establish the dynamic model of the drive. A numerical example was presented, and the results showthat the forces in a working cycle conform to the theoretical analysis.

Application of Meshless Method to Calculation of 2-D Elasticity Mechanics Problems

ZHAO Guang-ming, SONG Shun-cheng

2004, 17(4): 476-480.

[Abstract](1156)

Abstract:
The meshless local Petro-Galerkin method was applied to the calculation of two-dimensional elasticity mechanics problems by choosing properweight functions and basis functions. With the method, all integrals can be easily fulfilled on regular sub-domain boundaries, and to impose the essential boundary conditions, a penalty parameter can be used so that a positive definite and symmetric stiffnessmatrixmay be obtained. The comparison of its calculated resultwith that obtained using the ANSYS finite element method shows that the meshless method has the advantages such as high calculation accuracy, good stability and strong adaptability.

Improved Scheme of Channel Allocation of GSM/GPRS Networks

JIANGTi-gang

2004, 17(4): 481-484.

[Abstract](1187)

Abstract:
Based on the analyses of the typical channel allocation schemes such as FRA (fixed resource allocation) and DRA (dynamical resource allocation) for GSM/GPRS (global system for mobile communications/general packet radio service) networks, an improved channel allocation scheme, DMC_ DRA, was proposed, and its performances were analyzed. The new scheme may dynamically changes the minimumnumber of channels for a GPRS packet. In thisway a compromise between FRA and DRAmay be achieved to have better comprehensive performances such as channel utilization efficiency, packet transfer time and call blocking probability.

Modeling and Optimization of V2Controller for BUCK Converters

HEXiao-qiong, WUSong-rong, WANG Feng-yan

2004, 17(4): 485-489.

[Abstract](1705)

Abstract:
The models for BUCK converter and controlling loop were built using state-space average and linear methods and V2control technique, and the parameters for the compensative circuit in the controlling loopwere optimized based on optimal control theory. The simulation results showthat the transient speed of the optimized Buck converter is 50% faster and the bandwidth is about 4 times wider than that designed according to common practices.

Prediction of Chaotic Time Series Using Bilinear Adaptive Filter

ZHAOHai-quan, ZHANGJia-shu

2004, 17(4): 490-493.

[Abstract](1602)

Abstract:
Based on the delay-coordinate reconstruction and bilinear expressions in the phase space of a chaotic system, a bilinear adaptive filter was designed to predict low-dimensional chaotic time series. Experiments conducted on two examples of low-dimensional chaotic series show that, using the bilinear adaptive filter, the prediction process converges after about 50 samples are processed and the relative prediction error is less than 0.001.

Modification on TCP for Mobile Environments

ZHAO Chun-fen, FANGXu-ming

2004, 17(4): 494-497.

[Abstract](1400)

Abstract:
To improve the performances ofTCP (transfer control protocol) in mobile environments, an end- to-end solutionwas proposed based on ROMIPv4 (route optimization in mobile internet protocal version 4), which is named as TCP-BROMIPv4. In this solution, sender TCP may adjust its operation when it is switching to a new node if it receives a binding update message and a handoffwarning message. Simulation results show that TCP-BROMIPv4 shortens the traffic interrupted time and increases the number of packets transfered, greatly raises the throughput ofTCP in mobile networks .

Design of Optimal Incentive Payment Scheme for Enterprisers

GUO Yan, ZHANG Shi-ying, GUO Bin, LENG Yong-gang

2004, 17(4): 498-502.

[Abstract](1239)

Abstract:
An optimal incentive payment scheme was designed in order to prevent the problems of enterprisers adverse selection and moral hazard from occurring resulted from the absence of information on their real capability and their service cost and so forth. In this scheme, the revelation principle in the game theory is used to design different payment contracts to let enterprisers select, so a shareholder can judge their true information in terms of their selection. The analysis shows that the optimal payment scheme consists of compensation for their efforts, risk compensation and information rent, that the sensitivity of the optimal payment scheme is positively related to the expected compensation but negatively to the fixed compensation, and that efficient enterprisers work harder than inefficient ones and tend to choose high- powered incentives, lower fixed-price contracts and safer projects.

Research on Residual Distribution Based on Substitute Cost of Participant Resources

LUO Yue-long, KUANGMo, YUZhi-ping

2004, 17(4): 503-507.

[Abstract](1049)

Abstract:
Based on the analysis of the theoretical shortcomings of enterprise surplus arrangement, the substitute cost of participant resources was proposed as the key factor determining the residual distribution proportion in orderto resolve the problemthatmarginal contribution and risk, as the standard of determining the residual claims, are difficult to calculate. It was believed that the residual distribution based on the substitute cost not only incarnates equality in residual distribution, but also benefits to the raise of human resource worth and advances the vicissitude and optimization of enterprise institution.

Comparison Study on Value and Exercise Time of Options with Same Intrinsic Valu

FUShi-chang, XUYuan-dong

2004, 17(4): 507-510.

[Abstract](1123)

Abstract:
As an example, the values of continuous-dividend-paying call options and variable striking price options with the same intrinsic value at any time were respectively calculated by using the finite difference method. The research result shows that when the exercise price is variable, the typical conclusion,i.e. the non-dividend-paying American call option has no necessity to be exercised early, is correct only in the special case that the change in the exercise price is zero, and that the optionswith the same intrinsic value at any time have different values. In addition, the reasons for the difference and the factors influencing the difference were discussed.

Portfolio Optimization Model Based on Conditional Value-at-Risk

HUANGXiang-yang, CHENXue-hua, YANGHui-yao

2004, 17(4): 511-515.

[Abstract](1762)

Abstract:
Based on an algorithm proposed by R T Rockafeller and S Uryasev, a portfolio optimization model, mean-conditional value-at-risk model, was set up. This model measures riskwith conditional value- at-risk (CVaR) instead of standard deviation. It was optimized by using Matlab software and choosing six stocks in Shanghai and Shenzhen stockmarkets in China as a portfolio, and efficient frontier and investment proportion of the portfolio were obtained. By comparing them with the ones obtained using the traditional mean-variance (MV) model, the result indicates that the efficient frontiers gained by the two models are almost identical and also close to overseas research results, but there is a difference between the optimal investment proportions based on the mean-CVaR model and the MVmodel.

Distributed Decision-Making Support System Based on Coordination among Functional Departments

SHANCheng-ge, XIONGJian-gen, GUO Yao-huang

2004, 17(4): 516-520.

[Abstract](1451)

Abstract:
To provide an effective decision-making support for the enterpriseswhose functional departments are decentralized, a general model to describe the coordination process among functional departments of an enterprise was established based on the coordination theory and the structure of a distributed decision-making support system (DDSS) based on this model was designed. In this model, all functional departments of an enterprise are divided into a dominating department and non-dominating departments, and every department has the opportunity to become a dominating or non-dominating department. In addition, the information exchanged in the process of coordinating was definitely defined,i.e.the dominating department transfers the global decision vectortothe non-dominating departments, while the non-dominating departments transmit their marginal income vectors to the dominating department. Finally, the process of model solving was presented,i.e.limited times of department model solving and information exchanging.

Collusion of Agents and Its Control under Asymmetric Information

HANJian-jun, GUO Yao-huang, LANMin

2004, 17(4): 521-524.

[Abstract](1072)

Abstract:
By applying the game theory and the information economics, the effects of collusion on the incentive mechanism from a principal under the conditions of multi-agent and asymmetric information were investigated. It was pointed out that if there is no collusion among agents, a principal may raise the incentive by comparingtheir performances, nevertheless, the existence of collusionwillweaken the incentive effect. In addition, if a principal can detect and restrict the collusion, its situation can be improved.

Nonparametric Frontiers Evaluation of Eigenvalue Attributes of Third-Party Logistics Provider

WANG Ying

2004, 17(4): 525-530.

[Abstract](1495)

Abstract:
To design an evaluation method for third-party logistics providers (3PLPs) , an evaluation system consisting of 15 classification criteria was proposed, and its each criterion was graded into 5 levels. Three steps are included in evaluatingthe third-party logistics providers (3PLPs). The first is togive all the 3PLP candidates a score one by one for each criterion, varying from the highest 5 to the lowest 1. The second is to compare two 3PLP candidates with a classification criterion each time, and after all the candidates have been taken into account, 15 relative priority matrixes can be obtained and their eigenvalue attribute vectors can also be computed. The third is to design a nonparametric frontier algorithm with a constraint of an ordered set of preference weights for the classification criteria, so a sorted priority vector of the 3PLP candidates can be gained by using this algorithm to provide enterprises with an evidence for selecting a 3PLP. At the end, 2 verifying cases were designed to validate the reliability of the evaluation model.

Partner Selection in Supply Chain Alliance Based on Genetic Algorithm

DAI Ying

2004, 17(4): 531-534.

[Abstract](1494)

Abstract:
On the basis of establishing the multi-objective decision-making model for partner selection, a self-adaptive genetic algorithmwas proposed to optimize partner selection in a supply chain alliance, and an example was given. In this genetic algorithm, each member in a supply chain alliance has a self-adaptive ability to changes in environment in the genetic process through designing crossover probability and mutation probability. The example result shows that in the genetic algorithm the optimum global solution can be gained and the convergence speed is fast.

Optimal Algorithm for Multi-period Inventory System with Quantity Discoun

WANG Qing-rong, LIXian-lin, WENJu

2004, 17(4): 535-539.

[Abstract](1524)

Abstract:
To optimize milti-period inventory systems, in which quantity discounts are available, demand rates change over time, and checking and replenishments are made periodically, an algorithmwas proposed to search control rules. In the algorithm, a search tree with roots of the cumulative demands in the corresponding period is taken as the roots of the search tree, transforming the quantity discount problem into dynamic order quantity (DOQ) problem that is solvable with a dynamic programming algorithm. The proposed algorithm is capable to search the supplemental policy to minimize the cost of the concerned period. The validity of the algorithmwas illustrated with an example.

Initial Value Problem of Quasi-linear Hyperbolic Equations

ZHAZhong-wei

2004, 17(4): 540-543.

[Abstract](1032)

Abstract:
Based on theory of hyperbolic linear partial differential operator, the initial value problem of a kind of quasi-linear hyperbolic equations with non-zero initial values was introduced and studied. The Hilbert space and an important inequalitywere obtained using interior product of the Fourier transform on a quickly decaying functional space. The existence theorem of the solutions for the initial value problemwas proved using Schauder fixed-point theorem under some assumed conditions of known function.

Generalized Binomial Coefficient and Its Inversion

TANMing-sh

2004, 17(4): 544-546.

[Abstract](1162)

Abstract:
Then+1 order lowtriangular matrixPn[x]consisting of generalized binomial coefficients was studied with convolution formula and matrix multiplication. An inversion and some combinatorial identities related to the binomial coefficients were derived by using the properties ofPn[x].

On the Perturbation of Isometric Groups

2004, 17(4): 547-549.

[Abstract](1144)

Abstract:
LetAbe the infinitesimal generator of an isometric group on a Hilbert spaceHandBbe the perturbed operator ofA. Assume thatBis dissymmetrical and its relative boundary aboutAis smaller than one. Using perturbation theorems ofm-dissipative operation and self-adjoint operators, itwas proved thatA +Bis also an infinitesimal generator of the isometric group. An example of Schr dinger equation with initial value problemwas presented to illustrate the obtained results.

Sustaining Degree of Fuzzy Triple I Method Based on Residual Implication

WANG Qiong, HE Yi-nong, SONG Zhen-min

2004, 17(4): 550-553.

[Abstract](1663)

Abstract:
The residual implication operatorwas derived using triangularmodule, and the triple I algorithm for the residual implication operator that applies under certain conditions was obtained according to the properties of triangular module and the residual implication operator. The properties of the sustaining degree of these operators were analyzed. The generalized triple I formulae of FMP (fuzzy modus ponens) and FMT (fuzzy modus tollens) models were also proposed.

Experimental Investigation on Stress Relief Treatment with Pedrail-Type Heater

LIXiao-gang, YAO Wei-wei, WANGJia-kai, ZHANG Ze-hao

2004, 17(4): 554-556.

[Abstract](1472)

Abstract:
The distribution of temperature in a steel plate heated by pedrail-type heaterswas measured and the distributions of welding residual stresses as welded and after stress relief were investigated with hole- drilling strain-gauge method. The results show that, the temperature gradient along the thickness of the testing plate heated by a pedrail-type heater is neglectable and the temperature distribution is uniformafter a reasonable heating time, and that comparable effects of residual stress relief can be obtained with pedrail- type heater and in furnace.

Influences of Morphology and Size of Precursor on Nano-ZnO

CHENChuan-zhi, ZHOUZuo-wan

2004, 17(4): 557-560.

[Abstract](901)

Abstract:
Nano-ZnO powders with diameters of 8 to 130 nm were prepared from zinc nitrate and urea by homogeneous precipitation method. The precursors in different sizes and with rod-like or lamellar shapes were obtained by controlling the reaction procedures. Then, nano-ZnOof different sizes andwith spherical, net-like and rod-like shapes could be obtained under different calcination conditions. The microstructures and morphologies of the precursors and nano-ZnO particles were analyzed with TEM (transmission electron microscope) and XRD (X-ray diffraction), showing that the shapes and sizes are determined in a great extent by those of the precursors.

Combination Prediction of Traffic-Volume in Intersections Based on Wavelet Analysis and Kalman Filter

LI Cun-jun, YANG Ru-gui, DENGHong-xia

2004, 17(4): 577-580.

[Abstract](1544)

Abstract:
Based on the analysis of the distribution characteristics of urban traffic-volume, a combination prediction method based on wavelet analysis and Kalman filter was proposed to obtain more precise information on traffic-volume in intersections. With this method, some correlative data serials from an intersection are constructed, each data serial is treated respectivelywith Kalman filter and wavelet transfer, and the final result is formed fromthe predicted results of these serials. This method may be widely applied inthe fields of dynamic traffic prediction, such as the predictions of road-sect traffic-volume and traffic- volume distribution of intersections. Experimental results showthat the method can evidently decrease errors in the prediction and shows preferable robustness.

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2004 Vol. 17, No. 4