西南交通大学学报

Method for Predicting Internal Combustion Engine Emission under Steady Operational Condition

ZHOU Bin

2004, 17(2): 135-138.

[Abstract](1723)

Abstract:
To predict the emission characteristic of a combustion engine working under its normal operational condition, the emission preeiction neural network was established. It has non-linear simulation ability, combines the advantage of experiment with simulation, and uses some representative parameters available from experiment and simulation. This method is valid and provides a quick way to determine the emission behaviors of a combustion engine.

Three Dimensional Modeling and Numerical Simulation of Axial-Flow Pumps

YANG Chang-ming, CHENCi-chang, WANGJin-nuo

2004, 17(2): 139-141.

[Abstract](1790)

Abstract:
To automatically generate the 3D model of axial-flow pumps, a parametric modeling method based on AutoCAD and VB was proposed. Based on the COM interface of AutoCAD, the impeller of an axial-flow pump was modeled by connecting the hydraulic model database throughADO and by usingVB as programming language. The 3Dflowfield in an axial-flowpumpwas simulated usingthe meanNavier-Stokes equations, the standardk-εturbulence model and the SIMPLEC algorithm, and from the simulated result, its hydraulic performances were predicted. The results show that the numerical simulation can predict the performances of axial-flow pumps so as to provide a reference for hydraulic design.

Seismic Responses of RC Frame Structures with Special-Shaped Columns and Girder-Transfer Story

ZHANGXin-pei, SHUTao, ZHAO Yong, HUHong-wei

2004, 17(2): 142-146.

[Abstract](1629)

Abstract:
High rising buildings with a large bay supermarket on their two lowest stories and dwelling houses on the other stories were taken as the discussed object. Based on the relative national design codes and their engineering conditions, seismic responses of 72 high rising buildings of RC frame structures with special-shaped columns and a girder-transfer story were calculated respectively using the modal analysis method and the elastic time-history method, and in the calculation, different combinations of fortification intensities 7 and 8 and site soil typesⅠtoⅣwere considered. From the calculated result, the changes in their story drift, storyshear andmomenton structural bottomwere analyzed underthe condition of frequently occurred earthquakes, and some conclusions helpful for the design of high rising buildings were obtained.

Simplified Algorithm of Structural Reliability Index under Condition of Correlated Variables

LIBin, YANSong-hong

2004, 17(2): 147-151.

[Abstract](1521)

Abstract:
Based on the geometrical meaningof structural reliability index, the direct iteration calculation of a nonlinear function under the condition of correlated variables was discussed by using coordinate transformation and matrix operation. The calculation formulas based on the contribution value method was derived, and two numerical examples were given. The calculational results show that compared with the traditonal algorithms, this algorithm is simple in calculation and high in precisio

Experimental Research on Bamboo-Truncating Tunnel Portal for Single-Track Railway

CHENG Gang, QIUWen-ge, GAOXin-qiang

2004, 17(2): 152-156.

[Abstract](1753)

Abstract:
Model experiments with a geometric similarity ratio of 1∶30 were carried out to investigate the ground pressure and internal force of up and down bamboo-truncating tunnel portals for single-track railway. In these experiments, grade of up-slope and crossing angle between portal and railway center line were considered. The experimental results showthatground pressure and internal force around a tunnel portal are related to the thickness of overburden, the grade and the crossing angle: when the crossing angle is 90°, maximumground pressure and bend moment are at the invert bottom of a tunnel portal; when the crossing angle is 45°and 60°, maximum bend moment is on the side walls of a tunnel portal.

Artificial Neural Network Forecast Model for Slope Deformation of Large-Scale Dry-Doc

GUANQin-chuan, ZHANG Zhi-yong, FENGHao

2004, 17(2): 157-161.

[Abstract](1621)

Abstract:
Factors influencing the deformation of a dry-dock slope were analyzed. They are soil mass strength, time of non-protection slope, gradient of slope, number of layout excavation, depth of layout excavation, excavation step, rainfall depth and load on slope top. Based on the above and the typical deformation data measured in-situ, an artificial neural network model of predicting the deformation of a dry- dock slope was proposed, and the prediction result is consistent with the measured in-situ result. In addition, the vigilance values for slope deformation for the expanding slope technology, the four judgement modes for slope deformation and their corresponding control measures were put forward.

Railway GIS Model Based on Three-Tiered Architecture

HUANG Ze-chun, HUANGDing-fa

2004, 17(2): 162-166.

[Abstract](1428)

Abstract:
Based on the analysis of application modes of geographic information system (GIS), the basic idea and characteristics of three-tiered architecture were presented, and an integrated application model for railwayGIS was proposed based on three-tiered architecture. Furthermore, the whole planning of railway GIS based on three-tiered architecture technologies was disscussed. An application system of railway GIS was developed usingMapObjects and C++Builder, and this system characterizes high efficiency, stability and expansibility. The application result shows that it is feasible to apply three-tiered distributed technique to railway GIS.

Study on 3D Aerodynamic Admittance Function for Bridge Structures

LILi, LIAOHai-li, LIQiao

2004, 17(2): 167-171.

[Abstract](1298)

Abstract:
The concept of aerodynamic admittance function(AAF) for the buffeting analysis of structures was interpreted. Based on the discussion of AAFs used currently, their limitations were pointed out. The mathematical expressions of admittance functions suitable forthin plates in different conditionswere derived, and it was demonstrated that a 3D AAF can reflect the combined influence of the structural geometric dimension, the turbulentwind field characteristic and the reduced frequency, and is accordwith engineering practice. Finally, two types of methods to study the AAF through a wind tunnel testwere generalized.

Comparison of Three Models for Vehicle-Bridge Coupled Vibration Analysis

XIAOXin-biao, SHENHuo-ming

2004, 17(2): 172-175.

[Abstract](1832)

Abstract:
Three models for vehicle-bridge coupled vibrations, namely moving mass model, two-degree-of freedom vehicle model and four-degree-of freedom vehicle model, were derived using the D Alembert s principle and the hypothesis ofEuler-Bernulli beam. The dynamic responses of bridges tothe vehicle moving at different speeds were analyzedwith the models. The results showthat all the three models can reasonably determine the bridge vibrations under moving loads. However, more accurate results can be obtained with the last two models taking the springs and damping properties of vehicles into accunt.

Stability of Uncertain Linear Systems with Multiple Time-Delays

ZHANGKe-yue, CAO Deng-qing

2004, 17(2): 176-180.

[Abstract](1703)

Abstract:
A stability robustness criterionwas derived for uncertain linear systemswithmultiple time-delays by constructing a quadratic Lyapunov functional with an integral term. The robust stability bounds obtained are not necessarily symmetric to the origin in the parameter space, and can significantly enlarge the stability region for the uncertain parameters. A numerical example was given to demonstrate the results obtained and compare themwith those available in the current literatures

Fully Vectorial and Explicit Algorithm for Mould Filling

CHENG Zhi-qiang, Barriere T, Gelin JC

2004, 17(2): 181-185.

[Abstract](1655)

Abstract:
To meet the need of industrial application of mould filling simulation, a fully vectorial and explicit algorithmwas proposed on the basis of current explicit algorithms. For the simulation of different mould filling processes, the global solution for pressure field can be avoided by this algorithm, and only the matrix operations at element level are performed. The incompressible condition can be maintained by a corrective feedback operation. All the global solutions can be eliminated in numeral operation, and then the computational cost is closely proportional to the degree of freedom level. As a result, the simulation of injection processes is efficient, and parallel calculation for a high performance systemwith multi-clusters is easy to realize. The comparison of numerical results obtained with this algorithm and 3D simulation using MINI elements proves the validity and efficiency of the proposed algorithm.

Vendor-Purchaser Coordination and Quantity Discount Pricing Model in Supply Chain

MAZu-jun

2004, 17(2): 185-188.

[Abstract](1226)

Abstract:
Under the non-cooperative game, vendor and purchaser decide optimal lot size according to their own interests. One may be in an optimal condition, but the whole supply chain is not. To optimize the whole supply chain and attain the win-win goal, mutual optimal lot size models and the quantity discount pricingmodels were proposed under the cooperative game. The price discount can be determined with the models and by taking the bargaining powers and contributions of the both sides into consideration.

Long Periodic Oscillation in Flight Caused by Low-Level Wind Shear of Thunderstorms

WANG Yong-zhong

2004, 17(2): 189-194.

[Abstract](1604)

Abstract:
A typical low-level wind shear of thunderstorm activates long periodic oscillation of an aircraft, causing tracking deviation of the aircraft. On the assumption that thewind shear is sinusoidal, the effects of long periodic oscillation on the landing path of an aircraft were studied by computer calculation and with flight simulator. It is shown that the results obtained by calculation and simulation are not the same, implying that it might not be adequate to train pilots to manoeuvre the aircraft in low-level wind shear fully based on the available simulating modes of flight simulators.

Passenger Volume Forecasting of Guangzhou-Zhuhai Intercity Rapid Mass Transit

MAO Min, ZHANGJin, ZHOUHou-wen

2004, 17(2): 195-198.

[Abstract](1598)

Abstract:
Based on the analyses of the role, functions and passenger flow characteristics of Guangzhou- Zhuhai intercity rapid mass transit, the basic idea that intercity mass transit should be taken as a regional passenger corridorwas proposed, and the technical route of passenger volume forecasting based on the four- step forecasting method was put forward. By applying the combined model for passenger flow assignment, the passenger volume of Guangzhou-Zhuhai rapid mass transit was forecasted, and its daily passenger volume, passenger turnover, average transport distance, and maximum transect volume during rush hours were gained.

Development of Train out Report Subsystem of Railway Sub-administration Dispatch System

SHIHong-guo, PENG Qi-yuan

2004, 17(2): 199-202.

[Abstract](1244)

Abstract:
A train out report subystem was developed with Java according to the requirment of sub- administration dispatch system of TMIS (Transportation Management Information System) and the final users. The subsystem has the necessary functions such as inquiry, display, sorting, update, forward and printing. The database of the subsystem was developed with Oracle. The program has been used in the dispatch system of Shijiazhuang Sub-administration of Beijing Railway Bureau and earned good reputation.

Analysis of Starting Process of PMSM Servo System

CHENRong, DENG Zhi-quan, YAN Yang-guang

2004, 17(2): 203-208.

[Abstract](1394)

Abstract:
Based on the vector control principle of permanent magnet synchronous motor (PMSM), the current, voltage and rotating speed and their influencing factors of the motor in the starting process was analyzed. The linear speed-up phase in the starting process basically determines the starting time, and it can be accelerated by increase its starting torque to the maximum value. In the current set-up phase, the current response mainly depends on the DC voltage. A large filtering capacitor and three-phase supply is helpful to maintain the DC voltage. Both numerical simulation and experiment verified the analyzed results.

Characteristic and Control of Time Delay in Field Bus Control System

ZHANGXiang, XIAOJian, LIANJi-san

2004, 17(2): 209-212.

[Abstract](1481)

Abstract:
The characteristic of the transmitting delay of forward and feedback channels were analyzed. According to theworkingmodes of actuators, a linear control object is converted into time-driven and event- driven discrete time models. Two control methods for field bus control system were proposed. The first method transforms randomdelay into constant delay that is then compensated; the sencond method processes random delay directly. These two methods compensate each other and can eliminate the deterioration of delay to the control system performances of field buses.

Group Method for Realization of Spherical Basis Functions

ZHAOLiu, ZHUFeng, BAIXiao-bo

2004, 17(2): 213-216.

[Abstract](2035)

Abstract:
Based on the geometric feature of spherically symmetric structures, a 3D rotation group, SO3, was constructed. By applying the group theory of complete set of calculation operators, the classified basis functions of this group,i.e.the spherical functions, were obtained through group transformations, being identical with ones obtained using the traditional variable separation method. The result shows that the basis functions of a spherically symmetric structure can be obtained completely through group transformations, and as a result, the research provide a new way to solve electromagnetic scattering problems with complicated boundaries by using the moment method.

Development of Flickermeter and Application in Electrified Railways

HEJian-min, HUANG Zhi-qing, LIQun-zhan

2004, 17(2): 217-221.

[Abstract](1430)

Abstract:
As an important index of power quality, flicker directly indicates the voltage quality of power supply. Based on the design specifications for flickermeters published by the International Electrotechnical Commission (IEC), the mathematical model and digitalization of flickermeter were discussed in detail. Simulation was conducted and the results showed that the digital method fully satisfies the IEC standard. A flickermeterwas designed based on virtual instrumenttechnology, and ithase been used in electric railways.

Quantum Fluctuations in Damped Inductive-Coupled Electric Circuit

LIANGMai-lin, ZHAOLin

2004, 17(2): 222-226.

[Abstract](1227)

Abstract:
Based on the physical mechanismof the generation of resistance,i.e.the collision of electrons with lattices, the inductive-coupled electric circuit was quantized when there exists resistance in the coupling part. Quantum fluctuations were calculated for both the component circuits and the coupling part. And meanwhile, the temperature effect was included. The result shows that quantum fluctuations change with time, but reach definite values after a long time. The resistance in the coupling part affects the quantum fluctuations both in the coupling part and in the component circuits. Compared to the former results, the quantum fluctuations derived by this newmethod are smaller.

Design of Optical Heterodyne Fiber Sensor to Monitor Dam Deformation

TANGJin-sheng, HUANGXue-mei, YANG Ru-gui

2004, 17(2): 226-228.

[Abstract](1230)

Abstract:
To meet the requirement of dam safety in hydroelectric power stations, a kind of optical fiber sensors was designed based on the optical heterodyne technique, and its properties were tested. The test result shows that the measure precision of this kind of optical fiber sensors can reach to 50 nmso as tomeet the requirement of dam deformation monitoring.

Forward Tracking of Errors in Video Based on H.26L

JIANG Zhi-ping, PENG Qiang, LI Yun-feng

2004, 17(2): 229-233.

[Abstract](1419)

Abstract:
The error concealment technique introduced in H.26l decoder is not very effective on error resilience of high-motion pictures. An approach,named forward error tracking, compatible with the ITU-T video coding standard H.26L was introduced to stop the error propagation. The approach codes those corrupted macroblocks only by intra-update at the current frame to avoid too much increase in data volume. In addition, a newmulti-frame updating method was proposed to get smooth data stream. The experimental result shows that this technique is effective to stop the error propagation of high-motion pictures.

Development of Computer Simulation System for Overhauling of Hydroelectric Generating Unit

CHENXiao-shan, LAIXi-de, LIUXiao-bing

2004, 17(2): 234-238.

[Abstract](1599)

Abstract:
In order to make the reasonable and effective technical schemes for overhauling and solve difficulties in training overhauling workers in hydroelectric power plants, a computer simulation system for overhauling of a hydroelectric generating unit was developed by combining computer-aided simulation, virtual reality and multimedia techniques. The key techniques in this system include 3-dimensional digital modeling for all the parts of a hydroelectric generating unit, knowledge database setting up for overhauling technique and precess, implementation of 3-dimesnsional visualization, and dynamic simulation of assembling processes based on the virtual reality and multimedia techniques. This system has been successfully used in the overhauling of a large hydroelectric generating unit and the training of overhauling workers.

Strategic Partner Selection in Agile Supply Chain

BUXiang-zhi, WANG Wen-bin, WUZhen-ye

2004, 17(2): 239-243.

[Abstract](1381)

Abstract:
A multi-object evaluation model was established for strategic partner partnership selection in agile supply chain management under changing and uncertain market conditions and solved using fuzzy AHP. The experiment results showthatthismethod is efficient. Finally, some suggestionswere raised about the dynamic maintenance of strategic partnership, such as the reasonable evaluation of partner profit obtained from a cooperation mechanism and strengthening the leadership of key enterprises in cooperation.

Integrated System Model for Flexible Supply Chain

ZHANG Yun-bo, WUZhen-ye, YANG Cheng-lian

2004, 17(2): 244-247.

[Abstract](2736)

Abstract:
To determine the rational flexibility of a supply chain and improve its performances, the motivation for the emergence and evolution of a supply chain and its dynamic characteristic in its life cycle were systematically analyzed using supply-demand principle. The most important motivation is the demand. Six submodels were proposed, that is, research and development, resources, manufacturing, information, material flow and decision submodels. The submodels were then integrated into a model for flexible supply chain.

New Viewpoint of Dissecting Bertrand s Paradox —Analysis of CournotModel withModified Hypotheses

SHIQi-kai, SHIKai-ge

2004, 17(2): 248-252.

[Abstract](1192)

Abstract:
The analysis of the general Cournot model shows that the reason for strengthening, instead of dissecting, the Bertrand s paradox lies in that its assumed preconditions are far away fromthe real economic conditions. For this reason, the assumed preconditions were modified as follows: the cost of oligopoly manufacturers entering a professional market increases continuously and the marginal cost of products does not equal zero. Through rigorous mathematical deduction, the following conclusionswere drawn,i.e., the numberof oligopolies is limited by the increasing cost-of-entry, the market capacity is decreased by the existence of the marginal cost, and oligopolistic competition will not result in perfect competition easily.

Robust Stability Analysis for Interval DEA

ZHANG Shen-feng, WUYu-hua, GUOJun-peng

2004, 17(2): 253-236.

[Abstract](1547)

Abstract:
A new analysis method of robust stability analysis was proposed for general applications. In this method, the solution of the highest and lowest efficiency scores of each decision making unit (DMU) in an interval data envelopment analysis (DEA) is obtained firstly to determine the interval efficiency score of each DMU and classify DMUs. Then a so-called post-interval DEA model is built. Based on the optimum solution of this model, an index figuring out the stability of maintaining the highest score is introduced. As a result, the analysis of robust stability for interval DEA can be achieved. Finally, to explain the application of this method, an example was given.

Research on Characteristics of Methane Generation in Simulated Bioreactor Landfill

YANG Qiao-yan, LIQi-bin

2004, 17(2): 257-260.

[Abstract](1271)

Abstract:
The effects of the following factors(measures) on the generation of methane in bioreactor landfill were investigated through a simulation experiment. These factors(measures) are leachate recirculation rate, leachate heating before recirculation and microorganism inoculating by mixing sludge with solid waste. The research result shows that leachate heating before recirculation and microorganism inoculating by mixing sludge with the waste can quicken the generation of methane and accelerate the stabilization of solid waste, while a lower leachate recirculation rate is in favor of the generation of methane, but make against the stablilization of solid waste.

Analysis of Transfer-Probability Matrix of Repairable Series-Parallel System

NIUYu-qi, HEPing

2004, 17(2): 261-264.

[Abstract](1642)

Abstract:
From the fact that a series-parallel systemmade up of components has a complicated state space and transfer-probability matrix, the element classification and structural characteristic of the transfer- probability matrix of a series-parallel system with only a set of repair equipment were investigated. To describe the change ofthe transfer-probabilitymatrix, the conceptofgrowingmatrixwas introduced, and the change regularity of the transfer-probabilitymatrix, resulted fromthe variation of components in the system, was gained.

Multicast Routing and Wavelength Assignment Algorithm for WDM All-Optical Networks

YUZhou-qiu, LIUSan-yang

2004, 17(2): 265-268.

[Abstract](1311)

Abstract:
The problems of multicast routing and wavelength assignment in all-optical networks were studied. Based on wavelength graphs, a multicast routing and wavelength assignment algorithm for wavelength convertible optical networks was presented. The proposed algorithm deals with the routing and wavelength assignment as a unified process, and adjusts the cost of node with a multicast tree dynamically. It can construct a minimal cost multicast tree satisfying delay bound constraints. Moreover, the algorithm avoids the high complexity common to most delay-constrained heuristics.

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2004 Vol. 17, No. 2