西南交通大学学报

Theory and Key Technologies ofCross-Layer Design inW irelessM esh Networks

FANGXu-ming, MAZhong-jian

2005, 18(6): 711-719.

[Abstract](1245)

Abstract:
Due to the characteristics of wireless mesh network (WMN) in terms of topology, transmission link and traffic, the conventional layered protocol designmethods forwired networks can notguarantee the QoS performance forWMN. To reach a tradeoff between the efficiency of radio resources andQoS requirements tomultimedia traffic, it is required to explore the new designmethod forWMN based on physical layer, MAC layer, routing layer, etc. A unified cross-layermanager forall the layers is a necessity tomonitor the transmission performances or requirements, thereby to controlor adjust the relevant algorithms dynamically. The protocol and algorithm in respective layers are optimized by sharing the information on theQoS requirements to higher layers and the network states in lower layers, and multiple protocols in relevant layers are co-designed and co-optimized after the targets to be cross-layer designed are reasonably chosen. The generalprinciples andmethods of cross- layer design from physica,l MAC and routing layers toTCP layerwere presented respectively, and the theory and key technologies to be deeply researched were outlined, including the design of adaptive rate control and energy-savingmechanism, QoS-basedMAC protocol and routing protocol.

SelfadaptiveW atermarking Synchrorization Scheme Based on Image Connectivity

WANGHong-xia, LUO Jian

2005, 18(6): 720-726.

[Abstract](1359)

Abstract:
To improve the robustness and security performances of watermarking, a selfadaptive watermarking synchrorization schemewas proposed. In the scheme, the connected objects are obtained according to image connectivity, and the gravity centers ofbigger objects are selected as the reference points forwatermark embedding. Selfadaptive synchronization ofwatermark detection is ensured by the topological invariability of image connectivity and the stability of its gravity center. The high stablility of the reference points for watermark embedding makes watermarks robust not only under common image processing but also under global and local geometrical attacks.

New Threshold Cryptosystem againstChosen C iphertextAttacks Based on Pairing

MEIQi-xiang, HEDa-ke, ZHENG Yu

2005, 18(6): 727-730.

[Abstract](1001)

Abstract:
To improve the decryption efficiency of the Baek-Zheng scheme, a new threshold scheme was proposed based on pairing. In the new scheme, the dot product operation in the Baek-Zheng scheme is replaced by an inversion operation to design the verifying process. Because the verifying process needs only one pairing operation, the efficiency of threshold decryption is increased nearly one time, and the new scheme has the same encryption efficiency and the sizes of the ciphertext or the decryption shares, comparedwith that in the Baek-Zheng scheme. The new schemewas proved secure against chosen ciphertext attacks under theOracle-Diffie-Hellman assumption.

AnalysisM ethod forM yocardium Hypertrophy Images

XINGHao-yang, CHENXiang-dong, YANG Bo, WANG Zheng-rong

2005, 18(6): 731-734.

[Abstract](1357)

Abstract:
To increase the efficiency for measuring the size ofmyocardium fibers in evaluation of myocardium hypertrophy, an analysismethod formyocardium hypertrophy imageswas proposed based onHough transform. W ith thismethod, Hough transform is performed on the image ofmyocardium fibers to detected the direction of the fibers. Lines perpendicular to the fiber direction are generated, on which the distribution of gray levels are collected. The lines are divided into low gray levels representing fiberwidths and high gray levels reprensenting the gaps between the fibers. In thisway, the numberand the averagewidth of fibers aremeasured. Thettestresults (P>0. 05) show thatthere is no significantdifference between the resultsmeasuredwith the proposedmethod and by hands.

Improved DWRR Scheduling Algorithm in PhysicalFrame Time-Slot Switching

XUDeng-yuan, ZHANGXin-you, LIUWen-jie

2005, 18(6): 735-739.

[Abstract](1492)

Abstract:
Deficitweighted round robin (DWRR) does notmeet the delay requirement of rt-VBR (real-time variable bit rate) traffic. To solve this problem, an improved DWRR scheduling algorithm was proposed. A new service classwas added in the proposed algorithm tomeet the delay requirement of rt-VBR traffic, while scheduling nrt-VBR (non-real-time variable bit rate) traffic effectively. Simulation results show that the average delay of rt-VBR traffic inDWRR is3. 4mswith the improved DWRR, a decrease of30. 6% comparedwith that(4. 9 ms) with DWRR.

Creep Behavior ofQuasi-high-speed Dedicated Passenger Railway Track G irders during Construction

XUEWei-chen, WANG Wei, RENTing-zhu

2005, 18(6): 740-745.

[Abstract](1600)

Abstract:
Four large scaleT-beamswith a geometricalproportion of1∶5 weremade to simulate track girders of theQinhuangdao-Shenyang dedicated passenger railway. Their creep deformations during the construction were investigated experimentally. The research laid emphasis upon the effects of types of concrete and tensioningmeasures ofprestressed steelbaron the creep deformation. Moreover, program Sofistikwas used in the time-dependent full-range analysis of theT-beams during the construction, the errorbetween calculated and experimental results being less than 10%. Based on the above research, design suggestions taking the typesofconcrete, the tensioningmeasuresofprestressed steelbarand the rate ofreinforcement into accountwere given. The research results are useful to the design ofdedicated passenger railway track girders and the effective control of creep deformation.

Dynam ic Responses ofCable-Stayed Bridgeswith Different Structural Systems to Impact

ZHANG Wei, QIAN Yong-jiu, QIANG Shi-zhong

2005, 18(6): 745-749.

[Abstract](1837)

Abstract:
The purpose of this research is to probe into the dynamic responses of cable-stayed bridges to the attack of a conventionalweapon to provide an important reference for the feasibility studies of engineering protection and repair technology of importantbridges. A nonlinear finite elementprogram, LS-DYNA, wasused to simulate the dynamic responses ofcable-stayed bridgeswith differentstructural systems,i. e., suspension system, rigid-frame system and support system, to a long-rod projectile impactwhen bridge pylon is attacked. The effects of structural systems on the dynamic responseswere compared. The numerical results show that the local deformation in the region of collision is largest when bridge pylon is subjected to impact load parallel to the bridge axis, and the local deformation of the suspension system is least in the three systems. To a rigid-frame system, the dynamic plastic deformation of the intermediate column ofpylon under impact is larges,t and the dangerofbridge pylon fracture and the vibration responses of themain longitudinal girder aremostobvious.

“Erecting Cable before Constructing G irder”ConstructionM ethod of Self-Anchored Suspension Bridges

WEN Shu-dong, ZHENGKai-feng, HUANG Jun

2005, 18(6): 750-753.

[Abstract](1611)

Abstract:
To expand the application range of self-anchored suspension bridges, a novel construction methodwas brought up for self-anchored suspension bridges with a short span ranging from 100 to 400 m. It is called as“erecting cable before constructing girder”(ECBCG) constructionmethod and means that in the construction of a self-anchored suspension bridge the girder is constructed after the cable has been erected. Themaximum horizontal force that the piermustendurewas investigated, and some key problems, such as the size of the pier, the temporary join and the stabilization during construction, were discussed. The results show that the horizontal force can be acceptable for this type ofbridgewithin a certain range ofspan for thismethod to overcome the shortcoming of the construction method of“constructing girderbefore erecting cable”.

Evolution Law ofHysteresis Curve ofRock under Cyclic Loading

XU Jiang, YANGXiu-gui, WANGHong, WANG Wei-zhong

2005, 18(6): 754-758.

[Abstract](1275)

Abstract:
To investigate the deformation behaviors ofrock the evolution of the hysteresis curve ofrock under cyclic loadingwas studied by the experimental investigation of the deformation characteristics of fine sandstone under cyclic loading at three deformation rates and two stress levels. The research shows that the deformation curve of fine sandstone under unloading does not coincide with the deformation curve for loading to result in a hysteresis curve in the deformation curve, and the hysteresis curve is nearly unchangeable since the 2nd cyclic loading ata low stress leve.l In addition, fitting parametersof deformation curves for the 1st cyclic loading are different from those for the 2nd cyclic loading at different stress levels and deformation rates, but they tend to be unchanged gradually since the 2nd cyclic loading. Furthermore, the responses of rock deformation to differentdeformation rates and stress levels under cyclic loadingwill be differen,t and the fitting parameters change with deformation rates and stress levels.

Load-BearingM echanism ofCompound TunnelAnchorage

WANGHai-bin, GAO Bo

2005, 18(6): 759-764.

[Abstract](1654)

Abstract:
Based on a field test and FEM( finite elementmethod) numerical simulation, the load- bearingmechanism of the tunnelanchorage system ofsuspension bridgeswith pre-stressed anchor cable was investigated. The key parameters were determined through the back-analysis of the dynamic construction process. In the numerical simulation, interactions between anchorage and rockmass and between anchor cable, grout and rockmasswere simulated with zero-thickness contact elements. The research indicates that the initial pre-stress and free length of anchor cable determine the loads participated by anchor cable and anchorage on the tunnel anchorage system and their load-bearing occasion. There exists a least free length ofanchor cable to form a new confining pressure effect—rock anchoredwall to transfer and distribute stresses uniformly in rockmass.

NeuralNetwork Online Control to Road Tunnel with LongitudinalVentilation

ZHANG Guang-peng, LEIBo

2005, 18(6): 765-768.

[Abstract](1579)

Abstract:
An on-line controlmodel for road tunnelwith longitudinal ventilation was proposed based on neural networks and by combining traffic mode,l aerodynamics model and pollution mode.l Simulationwas conductedwith themode,l where the traffic volume changed from 1 000 to1 400 veh/h and the benchmark emission ratewas from 0. 008 to 0. 010m3/(veh·km). The results show that the proposed system increases or decreases the number of fans in realtime following the changes in the traffic volume and the benchmark emission rate, so that the volumetric fraction ofCO, as a control targe,t is controlled justunder the standard limit(150×10-6).

New Idea on Treatment ofLeachate from Municipal SolidW astes —Application ofBioreactor LandfillTechnology

LIUDan, LIQi-bin

2005, 18(6): 769-773.

[Abstract](1407)

Abstract:
To solve the problem of expensive cost and complicated process of treating leachate from municipal solid wastes, simulating landfill experiments were conducted based on analyzing the characteristics of leachate treated by containment landfills and bioreactor landfills. The results indicate that the elimination ratios of COD (chemical oxygen demand) and NH3-N in leachate from semi- aerobic bioreactor landfills reach up to 95% and 98% respectively. This shows a strong treatment function ofbioreactor landfills, and this function can be used to lighten the greatpressure of leachate treatmen.t The research provides a new idea and pathway for the treatment and pollution control of leachate from municipal solidwaste landfills.

Deformation Behaviors of63Sn-37Pb Solder Alloy under Uniaxially Cyclic Loading atRoom Temperature

YANGXian-jie, SHAO Er, LUO Yan, SUN Ya-fang, XU Yin-jie

2005, 18(6): 774-778.

[Abstract](1232)

Abstract:
The uniaxial cyclic deformation behaviors of 63Sn-37Pb solder alloy were experimentally investigated underdifferentdwell times, strain rates, strain amplitudes, strain-time loadingwaveforms and loading histories. The study shows that the solder alloy has a significant strain-rate sensitivity, its instant deformation behavior under uniaxial cyclic loading is dependent on dwell time, loading waveform and strain amplitude, but the dependence of the cyclic deformation behavior on loading history is not significant.

Effects ofAsymmetricalParameters of Structure on StructuralFlutter Velocity

YEXian-hui, YANG Yi-ren, LIUFei

2005, 18(6): 779-783.

[Abstract](1239)

Abstract:
A flutter differential equation for two coupled asymmetrical control surfaces was derived usingLagrangian equation under the supposition of quasi-steady aerodynamic forces. Examples were presented to analyze the effectsofasymmetricalparameterson the critical fluttervelocityunderdifferent coupled stiffness. The results show that the asymmetry of structural parameters is beneficial to the increase in fluttervelocity; butwhen the values ofasymmetricalparameters are large enough to change the fluttercharacteristicsof the system, the asymmetricalparametersmightnot increase fluttervelocity.

ImprovedM ixed-M odeM ethod ofValid ElasticM odulus ofComposites

TIAN Yun-de, QIN Shi-lun

2005, 18(6): 783-787.

[Abstract](1207)

Abstract:
Based on the continuummechanics theory, amixedmodewas setup to investigate the valid elastic modulus of composites. An improved mixed-mode method was proposed, and the revised formula of calculating the valid elastic modulus of compositeswas given. The calculational results of the valid elasticmoduli of two composites show that the biggest error is 9% for the improved method and over23% for theVoightmode,l theReussmodel and theHalpain-Tsaimodified formula, and the difference between the calculational and experimental curves of the valid elastic moduli of the two composites is small for the improvedmethod and great for the threemodels.

M odel ofRailway Transportation Channel Share Based on Finished Dedicated Passenger Line

PENG Qi-yuan, YIN Yong, YANHai-feng

2005, 18(6): 788-792.

[Abstract](1712)

Abstract:
To sufficiently give play to the transportation capability of railway transportation channels consisting of a dedicated passenger line and an existing line, factors influencing the share of railway transportation channels were analyzed, and a mathematical model of railway transportation channel sharewas setup. In thismode,l the optimal object is transportation cos,t traveling speed and routine transportation regulation, and the restriction condition is carrying capacity. In addition, thismodelwas improved by using the satisfaction optimization, themulti-objective optimizationwas transformed into a single objective optimization problem, and the corresponding algorithm was given. The research provides a theoretical reference for the share of railway transportation channels.

BilevelProgramm ingM odel for C ity Road Network Planning and ItsApplication

QUPeng-ju

2005, 18(6): 793-797.

[Abstract](1623)

Abstract:
The objectives ofcity road network planning and shortcomings of the available programming modelswere analyzed. A bilevelprogrammingmodelwas proposed for city road network planning, and iteration optimization algorithm was used to solve themode.l As an example of application, themodel was applied in the road network planning ofLanzhou City. Current situations and the future demands on the traffic in the citywere elaberately taken into consideration. A scheme of road network planning forLanzhouwas presented, inwhich a reasonal pyramid distribution of the road typeswas formed.

Vehicle Routing Problem with FullLoad and Driving Distance Restriction

WEIHang, LIJun, WEIJie

2005, 18(6): 798-802.

[Abstract](1469)

Abstract:
The graphmodelwas applied to solve the vehicle routing problem with full load (VRPFL) and a driving distance restriction. A route choicemodelwith a driving distance restriction was setup through transforming the driving distance restriction into the objective restriction. The genetic algorithm based on decimal codingwas given to solve theVRPFLwith a driving distance restriction and verified through an example. The result of the example shows the validity of thismethod to solve the VRPFL with a driving distance restriction.

Design ofOptimalRebate ofM anufacturer to Dealers

HUPei, TANDe-qing, YUBi-jun

2005, 18(6): 803-805.

[Abstract](1243)

Abstract:
To solve the problems of the optimal rebate standard ofmanufacturers to sealers and the lowest sales volume corresponding to the standard to stimulate dealers efforts and gainmore profits, a gamemodelbetween the relationship of amanufacturer and its sealerswas set up and analyzed. The research shows that the optimal rebate of amanufacturer to its sealers fallswith the increase of rival dealers productprice, and that the lowestsales volume demanded by the optimal rebate increaseswith the increases of total socialdemand for a productand productprice given by a rivalmanufacturer to its sealers, fallswith the raise ofproductprice given themanufacturer to itselfsealers, and hasno relation to themarketprice of the product.

Choice ofVenture InvestmentBehaviors of Investors

PENG Wei-min

2005, 18(6): 806-810.

[Abstract](1240)

Abstract:
To provide a correct guidance for investors, the factors influencing the choice of venture investmentbehavior of investors were investigated from the point of view of behavioral finance and through analyzing the risk-averse utility curves, expected utility, investment net present value and opportunity cost for an investor. These influential factors include the definition ofan investor s attitude to venture investmen,t the arrangementof investment tools in phases, the holding ofopportunity cost in investment decision and the application of investment options. The research shows that investor s attitude to investment venture directly affects the seeking to venture profit and reflects the mental critical of the investor to venture endurance. Alongwith the development of a venture enterprise, the investment trends to equity rights and debtrights ofan investorwilldecrease and increase respectively. When the unitoutputprice of items remains constan,t whether to keep or to exert the options lies on the comparison between opportunity costand net investment income. On the contrary, whether investor waiting for or raising investmentwillbe determined by the decrease or increase ofunitoutputprice.

Order AllocationM odel in Supply Chain and Hybrid Genetic Algorithm

JIXiao-li

2005, 18(6): 811-815.

[Abstract](1529)

Abstract:
A mixed integer linearprogramming (MILP) model forordersdispatching in a supply chain withmulti-produc,t multi-order, and multi-period was proposed. To shorten the time for solving the model and avoid the illegal chromosome, a hybrid genetic algorithm that combines genetic algorithm with a heuristic rule was designed. An example was presented to verify the model and the algorithm and to compare the resultwith that calculated with the OR module of commercially available software SAS. The results of example show that the error of the optimized solution by the proposed model and the algorithm is 2. 3% compared with the OR module, and the time consumed is 0. 89% of that by OR.

Effect ofProportion Allocation Based on Past Sales on Supply Chain Performance

ZHAO Xiao-min, HUANG Pei-qing, WANGNan

2005, 18(6): 816-820.

[Abstract](1345)

Abstract:
To investigate whether proportion allocation based on past sales, compared with the fixed allocation, can improve the performance of a supply chain, a two-stage game modelwas set up to a supply chainwith one supplier andmultiple retailers, and the effects of the proportion allocation based on past sales on the performance were discussed. In addition, the fixed allocation and the proportion allocationwere researched comparatively. The results show that the proportion allocationwillmake the retailers ordermore than they need to increase the supplier s profits at the expense of the retailers profits, so it can improve the performance ofoverall supply chain only under some conditions.

EBA M odel for Relationship between Econom ic Growth andM arketization Level in China

WANG Li-ping, TANDe-qing

2005, 18(6): 821-824.

[Abstract](1361)

Abstract:
The conception, character and testingmethod of the model ofEBA (the extreme bounds analysis) were summarized systematically, and the problems existing in its applicationswere analyzed. A demonstration analysis of the relationship between the economic growth and marketization level of Chinawas carried outby using themodelofEBA. The resultshows that the levelofmarketizationwill benefit the economic growth in China butdoes not immediately produce a greateffecton the economic growth.

K-Dimension of the Graphs of a C lass ofBush Functions

WANGHong-yong, XU Shao-yuan

2005, 18(6): 825-828.

[Abstract](1025)

Abstract:
TheK-dimension of the graphs of a class of Bush functions was studied. These fractal functions are defined by using the expression of the Cantor series of real numbers. The expressions of the upper and lowerboundaries for theK-dimension ofsuch graphswere obtained. It is shown that the K-dimension of the graphs of such functions is equal to their box dimension and packing dimension when the functions are defined by theb-adic expression of realnumbers.

Distribution Theorem s for Values ofPower Functions with Complex Bases and Exponents

TONG Ji-xian

2005, 18(6): 829-831.

[Abstract](901)

Abstract:
By theorem of real funcion, the distribution theorems for infinite numberofvalues ofpower functionswith complex bases and exponentswere discussed. If the exponentαis an irrationalnumber, the the values are densely distributed on a circle. Ifαis a pure imaginary number, the values form an isolated setand are distributed on a ray. Ifαis a complex number (non-realnumber), the values are distributed on a logarithmic spiral.

New Exact Solutions of the Lienerd Equationswith Fifth-Order Stronger Nonlinear Terms

TIAN Ying-hui, CHENHan-lin, LUO Yuan

2005, 18(6): 832-836.

[Abstract](1020)

Abstract:
By constructing auxiliary differential equations, newmultiple exactsolutions of the Lienard equations with fifth-order stronger nonlinear terms were obtained, including solitary solutions, trigonometric function solutions, Jacobian elliptic function solutions. By use of the results , new multiple explicit exact solutions ofmany important nonlinear evolution equations, such as the Kundu equations, the differential Schr dinger equations, the nonlinear wave equations in mechanics, PC equations and so on, can be solved.

H ierarchic Construction ofConceptLattice

XIE Run, LIHai-xia, MAJun, SONG Zhen-ming

2005, 18(6): 837-841.

[Abstract](1408)

Abstract:
Two importantproperties of hierarchical concept lattice were presented: the concepts in a same layerare incomparable and a concept isoverlayed by at leastone concepton the upper layer. The general formula for the object and atributemappingwas derived, and a theorem, which describes the structural invariability of objects during their construction, was obtained. A new algorithm was proposed to construct the concept lattice occording to the properties and theorem. The proposed algorithm constructs the lattice lay by lay based on the hierarchical structure of concept lattice. No abundant concept is created, because filtration is carried outduring construction of concepts.

Lattice Implication Algebraic Equations in Lattice Implication Algebras

PANXiao-dong, XU Yang, ZHANG Qing

2005, 18(6): 842-845.

[Abstract](1237)

Abstract:
According to the theory about logic algebraic equation, the notion of lattice implication algebraic equationwas proposed. Some typical one varialbe lattice implication algebraic equations in lattice implication algebrasLwere discussed. The necessary and sufficient conditions for existance of solutions for the equationswere presented. Based on the discussions, itwas proved that the solution sets of the equations are convex sublattices ofL.

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2005 Vol. 18, No. 6