Abstract:Reliability-based seismic design of lifeline networks is proposed.The paper also presents a network topology optimization method,with which network topology can be automatically generated and meaningless solution can be repaired.With this technology,lifeline networks can be designed numerically by taking the construction cost,economic rationality of operation and seismic reliability into consideration.

Abstract:By taking the independence of space stochastic field and random process into consideration,the conventional perturbation pseudo excitation method(PPEM) is improved and mean or variation of stochastic response can be directly obtained.During the previous researches,the independence was neglected,and so stochastic response variation was function of stochastic variables.As a result,means and variations of response variation had to be solved.Computational results of single degree of freedom(SDOF) compound stochastic system reveal that the improved PPEM is more reasonable.Being different from the fact that the response variation of stochastic system based on the conventional perturbation pseudo excitation method is decided by reliability,response variation based on the improved perturbation pseudo excitation method is not decided by reliability,which is in conformity with the statistic regularity.In fact,variation describes only the divergence of random data and is independent of reliability.

Abstract:The characteristics of liquefiable soil during earthquake excitation of free field were identified based on multiple acceleration records in shaking table tests.The time histories of cyclic shear stress and shear strain in the soils were evaluated from the accelerations recorded in the soil.These histories were used to estimate variation of soil dynamic shear moduli and material damping characteristics with shear strain amplitude.Soil stiffness properties agree well with those obtained based on laboratory tests.The material damping computed from acceleration records was however much higher than that independently measured in laboratory tests.Pore pressure buildup was found to affect shear wave velocity in the soil and weaken soil stiffness.

Abstract:Efforts are made to grasp the probability information of the stress strain relationship.Firstly,a class of mesoscopic damage mechanics models of concrete is listed to understand the mesoscopic damage evolution characteristics of concrete material.Then the Karhunen-Loeve orthogonal decomposition is adopted to simulate the stochastic field mentioned in the former model.Based on the generalized probability density evolution method (PDEM),probability density function (PDF) of stress strain relationship in unaxial loading condition and its evolution are provided.In the end,the comparison between the theoretical and experimental results verifies that the probability density evolution process of constitutive relationship for concrete material can be obtained from this method.

Abstract:To resolve the serious breakage and leakage problems for the cast iron water mains buried in the early years in the water-supply system,pipe stresses were firstly calculated based on the pipe soil interaction model,and the failure prediction model for the cast iron pipe was developed,based on the corrosion model,the residual strength evaluation method and the failure criterion.Monte Carlo (MC) simulations were used to perform the probabilistic analysis,and the influence parameters analysis was given.Results show that pipes in large diameters are often broken because of circumferential stresses,and pipes in small diameters are prone to fail due to longitudinal stresses.The influence on the failure probability is large due to soil bedding lost induced by the breakage or uneven settlement when the corrosion depth reaches a certain depth.The corrosion model parameters,unsupported bedding length,and the residual strength parameters have large influence on the distribution of the safety factors for the cast iron pipe.The corrosion is one of the most important factors leading to the pipe failure.Reducing corrosion pit depth growth by using corrosion control technique can be the most effective way to decelerate the breakage growth rate and prolong the service life.

Abstract:The mechanisms of cross-wind effects of high-rise buildings are very complicated,which are associated with the incident turbulence,the wake and the aerodynamic feedback.Although considerable research efforts to assess cross-wind effect have undertaken worldwide for decades,no widely adopted sophisticated theory and method are made,further-more,no relevant guidelines are made in the load standards and codes of most countries.These worldwide research subjects of cross-wind effect include three important parts,the determination of cross-wind aerodynamic force,the identification of cross-wind aerodynamic damping and the calculation methods of across-wind equivalent static wind loads.Wind tunnel technique,data fitting technique and parameter identification technique are the principal means to determine the cross-wind effects of high-rise buildings.Based on the problems and deficiency of across-wind response research,some research emphases are proposed:the effect of complex building shape to aerodynamic forces,the identification,mechanisms and influence factors of cross-wind aerodynamic damping,calculation methods of equivalent static wind load and 3-D coupling problems of complex high-rise buildings.

Abstract:This paper presents an investigation of the interference effects to determine a systematic method to research the characteristics of dry coal sheds under (no) interference condition,wind-induced response.Based on the wind pressure distributions on a typical dry coal shed from wind tunnel tests on the rigid model,the wind-induced dynamic responses are computed in frequency domain by using mode superposition method (CQC method).The characteristics of mean，fluctuating and peak responses at different wind directions are analyzed.It is found that the maximum responses in the same region of roof have the similar regulations under different interference conditions.Then the characteristics of gust response factor,background/resonant response and power spectrum density are investigated carefully.When the interfering building is located upstream and downstream respectively,mean responses contribute differently to total responses;and background components contribute to dynamic responses differently either.However,as a matter of fact,some specific modes contribute more to dynamic responses under different interference conditions.

Abstract:In order to equilibrate traffic flow on urban expressway network,and improve the efficiency of traffic operation,the paper proposes an feedback optimal control model for urban freeway by using Model-based Predictive Control (MPC) framework.The control task is formulated as a dynamic,nonlinear,discrete time optimal control problem with constrained control variables.The network traffic process is modeled by a macroscopic network traffic flow model,which is deterministic,discrete time,discrete space,and macroscopic and suitable for model based traffic control.Feedback control is realized by solving the optimization problem for each control interval over a sufficiently long future time horizon.Simulation results for a case study show that with the proposed MPC traffic control,the time-dependent traffic characteristics can be accounted for;a high degree of control benefits can be guaranteed,and reference for ATMS is provided.

Abstract:An analysis was made of the characteristics of both transit service and passengers with traveler information system,and also the way they affected each other in the service process.Amodel was established about passengers’ way of cognition and their travel behavior in response to both physical service and multivariate information.Finally,the architecture of the multi-agent-based simulation system,SimCUBE,was introduced and analysis of simulation results was made correspondingly.

Abstract:To design and develop the real-time traffic navigation system (RTTNS) in Symbian operating system (OS),several key technologies were studied.The R-tree spatial index structure was improved based on Hilbert fractal and minimum boundary rectangle (MBR) decomposion.Active object was utilized to deal with non-preemptive multitasking in Symbian OS.A portable vector map library was designed with “Open C” technology.A RTTNS was developed in Symbian S60 OS.The experiment results of several cities show that the RTTNS is highly stable and effective.

Abstract:Based on ABAQUS software,a comprehensive 3D finite element model to analyze the structrual response of jointed rigid airport pavement was established by distributing the stiffness to the nodes along the joint using the concept of contributing areas.Bending stress and deflection for typical pavement structure with varying subgrade strength and joint stiffness on edge loading case were calculated under various landing assemblies.Considering the effect of base course on the load transfer efficiency at joints,a new relationship between the deflection load transfer efficiency obtained from Heavy Weight Deflectometer(HWD) and joint stiffness is established,and relationships between the deflection load transfer efficiencies and the stress load transfer efficiencies subjected to various landing assemblies are established as well.The results provide an approach to evaluate load transfer efficiency at joints and analyze bending stress at slab edge.

Abstract:Low-plastic porous cement concrete,a high-fluid porous cement concrete,is doveloped for special requirements of base construction in urban highway.The paper presents the strength standard of design and suggested gradation for the low-plastic porous cement concrete,and also a discussion of the molding method of sample in the laboratory.When designing the low-plastic porous cement concrete,many factors should be considered such as fly ash addition,efficient water reducing agent addition and water-cement ratio and so on.An analysis is made of the effect of these factors on the slump,void and strength of low-plastic porous cement concrete.Based on the research,the component of low-plastic porous cement concrete is proposed.

Abstract:Simulated tests were carried out to investigate the characteristics of the emission of volatile organic compounds(VOCs).The emission rates of total VOCs (TVOCs) were 9.67~20.3 mg·kg-1 in 72 h after municipal solid waste(MSW) generation.The lowest emission rate corresponded to the high-level ventilation condition with the oxygen concentration in the MSW layer around 18%.The ketones and the thioethers accounted for 70%~80% and 10%~20% of TVOCs,respectively,which were the major odorous catalogues.During the period of 72 h,the TVOCs emission was high in 0~24 h,descended in 25~48 h,and rose again in 49~72 h.Contrastively,the emission of thioehters kept ascending during 72 h.The study suggests that the VOCs emission can be reduced by high-level ventilation and inoculation with aerobic microorganisms.

Abstract:A new amine-modified hypercrosslinked polymeric resin (NDA) was prepared by introducing dimethylamine groups into hypercrosslinked copolymer of styrene and divinylbenzend (NDA150).The adsorption behaviors of o-hydroxybenzoic acid,p-hydroxybenzoic acid and 2,6-bihydroxycenzoic acid onto NDA150 and NDA were studied.The results show that the adsorption equilibrium data of o-hydroxybenzoic acid,p-hydroxybenzoic acid and 2,6-bihydroxycenzoic acid on NDA150 and NDA were well fitted by the Langmuir,Freundlich and Redlich-Peterson isotherms in the studied concentration ranges.The adsorption was exothermic and basically of physical character.NDA had higher adsorption affinity and capacity for the above hydroxybenzoic acids than those of NDA150,which was mainly due to the influence of amine group on NDA.

Abstract:This paper illustrates the input ways including elevated N deposition,biological N fixation,man-made N and runoff N input;the output processes including plant harvest,soil NH3 volatilization,denitrification and leaching,runoff output,etc;and biogeochemical cycle of nitrogen through N fixation,mineralization (ammonification),nitrification,denitrification in wetlands as well as the relationship among them.To obtain quantitative relationships of N,C and P is one of the main problems in the present research,in which the key issue is to investigate relations between N migration amount and environmental factors in the wetland system.The influence of wetland nitrogen cycle on the global environment is also discussed.

Abstract:An investigation was made of the effects of land utilization of sewage sludge compost on growth and heavy metal accumulation in tall fescue (Festuca arundinacea Schreb) and marigold (Tagetes erecta) in the pot scale experiments.The results show that sewage sludge compost significantly increases the level of Zn,Cu,Pb in the soil.The plant biomass,height,absorption of total nitrogen and phosphorus increase gradually with sludge compost application ratios of 0~10% in Festuca arundinacea Schreb or 0~5% ratios in Tagetes erecta.The enrichment of heavy metals in both plants decrease in an order: Zn>Cu>Cr,Ni>Cd,Pb.And Zn,Cu,Cr,Ni enrich more significantly in Festuca arundinacea Schreb than Tagetes erecta.In a word,the highest elimination of heavy metals in mixed soils,especially for Zn and Cu,is obtained at 10% or 5% sludge compost ratio for Festuca arundinacea Schreb or Tagetes erecta,respectively.

Abstract:The structural morphology and spectra characteristic of Ciprofloxacin (CIP) and Norfloxacin (NOR) was strongly affected by the pH.In strong acidic solutions,fluoroquinolone molecules exist as strong cation to achieve a weaker intensity.When the pH value increases to 3~4,fluoroquinolone molecule exist as zwitterions,which is the strongest fluorescence form to have maximum intensity;the maximum exciting-emission wavelength (λexλem)of CIP and NOR were 280＼459 nm and 281＼450 nm,respectively.Along with the increase in neutral pH value,fluoroquinolone molecules exist as weak anion,fluorescence spectrum and UV spectrum change,the intensity decreases;under basic condition,fluoroquinolone molecule exists in anion ion form,and fluorescence and UV intensity decreases with pH increasing,but spectrum remains essentially constant.

Abstract:Considering the elastoplastic deformation of material,a transient dynamic analysis for rear suspension is conducted under the boundary condition of cobblestone strengthen road loads.Crack initiation life of rear suspension is accounted by using traditional uniaxial strain life method.However,biaxial analysis of stress—strain time history indicates that the hazardous areas of rear suspension are subjected to a multiaxial non-proportional loading.Based on multiaxial fatigue theory,the material non-proportional appending hardening mechanism and crack type are considered.The multiaxial fatigue life is predicted by using Bannantine model and Wang-Brown model which are deduced with the critical plane method.Uniaxial fatigue life on the basis of the same material is also predicted for a comparison.It indicates that the life under the non-proportional loading is largely decreased and the result predicted by uniaxial fatigue theory is dangerous.

Abstract:Based on wavelet packet transformation(WPT)and Euclidean space theory,a method was explored to identify noise source under the non-stationary conditions.Taken the condition that the fans in fuel cell vehicle(FCV)accelerated from 1000rpm to 3800rpm as example,this method was introduced and proved to be effective by identifying the main noise source both inside and outside of FCV,and the main vibration source in the position of front seat.So it can be applied in indentifying the main noise source in automotive un-stationary conditons such as acceleration conditions,deceleration conditions,and so on.

Abstract:The theoretical model and FEM of three-dimensional transient thermo-mechanical coupling of the ventilated disc brake with asymmetrical inner and outer disc plate thickness are established,taking into account the real friction-velocity curve of the disc pad couple.Based on the finite elements analysis of the model,the predictions of the thermo-mechanical responses of the brake disc are presented,including disc transient temperature field and normal stress in radial,circular and axial directions,disc lateral deformation and disc thickness variation.Numerical predictions of the disc surface temperature and lateral deformation are compared with experimental measurements obtained by thermocouples and non-contact displacement sensors on test rig,and the simulation results are consistent with the experimental results.The simulation results reveal the complex coupling relations among temperature,normal stress and thermoelastic deformation due to the ventilated slots and asymmetrical inner and outer disc plate thickness,and the interactions among frictional,thermal and mechanical dynamics.

Abstract:An experimental research was made into the diesel taxis on its fuel economy,pollution emission,and reliability performances of 10% and 5% jatropha-based biodiesel blend with conventional diesel (volume ratio,recording as BD10 and BD5 respectively).The experimental result shows that pollution emissions of diesel taxis fueled by BD10 and BD5 are fully complied with current national emission standards.The fuel consumption per 100 kilometers of BD10 fueled diesel taxies is a little higher than that of conventional diesel fueled taxies,and the NOx+HC,NOx,CO and PM emission of BD10 fueled taxies reduces about 5.3%,9.1%,15.9% and 8.9% respectively.Moreover,the fuel consumption per 100 kilometers of BD5 fueled diesel taxies is almost the same with that of conventional diesel fueled taxies,but the NOx+HC,NOx,CO and PM emission of BD5 fueled taxies reduces about 3.5%,4.9%,10.5% and 3.6% respectively.And,the deposit carbon on fuel injector head of biodiesel fueled taxies increases a little,which,however,does not affect the taxi work.

Abstract:The thermodynamic analysis of hydrogen production from dimethyl ether(DME) auto-thermal reforming was carried out in order to study the influences of the ratio of steam to DME,the ratio of oxygen to DME and temperature on equilibrium composition.Theoretical maximum energy efficiency and product fraction in the reaction system were analyzed.The results indicate the complete reaction for the thermo-neutral oxygen to DME ratio at a given steam to DME ratio,when the maximum theoretical efficiency can be arrived.The hydrogen mole fraction above 50% and its yield above 80% can be obtained under the conditions that the ratio of steam to DME is 2.0~4.0,oxygen to DME 0.4~0.5,the temperature is between 150~350 ℃,the carbon monoxide mole fraction is below 5% and theoretical maximum energy efficiency can be achieved 85%.

Abstract:By building up the railway wheelset kinematics model,creep force model,braking force open-loop and closed-loop control model,the simulation method on anti-sliding control of braking system is discussed.Regarding the anti-sliding control unit of electro-magnetic brake system,the pneumatic circuit model and anti-sliding control strategy model are also built up based on the DHSplus software.Co-simulated with MATLAB,the characters and parameters of anti-sliding control unit of electro-magnetic brake system are analyzed.In this work,the hardware and software of an anti-sliding device are designed.Some tests and simulation results show that these models are reasonable and useful to speed up the development and integration of anti-sliding control system.

Abstract:The paper presents an analysis of the principle of stack buffer overflow attacks and basic attack patterns for Intel 80×86 architecture and C/C++.Then,the merits and drawbacks of the existing dynamic buffer overflow prevention methods are discussed.On the basis of the address obfuscation and integrity checking,this paper presents a new dynamic buffer overflow prevention method based on k circular random sequence.This improved prevention method can defend attacks of multiple patterns with high probability and enhance the intrusion-tolerance capability of the vulnerable software.

Abstract:A class of time-varying singular system is investigated.A conclusion is drawn that the time-varying singular system satisfying some conditions is stabilizable.An iteration method for solving the corresponding Riccati matrix differential equation is established.Moreover,an example is given to illustrate the process for obtaining stabilizing feedback control of a time-varying singular system.

Abstract:A new methodology is proposed for construction of weighted element clique graph (WECG) based on nodal degrees of freedom.The Fiedler vector of the Laplacian Matrix of WECG is used for reduction of the bandwidth and profile of stiffness matrix in finite element analysis.The present method is not only suitable for common finite element models,but also for models including different nodal degrees of freedom of element in number and usually leads to better results for the latter models compared with common methodology of algebraic graph theory based on Laplacian Matrix of element clique graph.A pre-processing routine based on the present method is embedded in a finite element program,which can reduce the generation task of finite element model without consideration of nodal ordering.The numerical experiments show that the present method is efficient.

Abstract:By modifying the dynamics of stock price,a SDE of stock price with default risk is obtained,and transformed to an adjusted SDE in neutral-risk world.Computing the cash flow by containing the recovery,a variational inequality is derived,and then based on the equation,an explicit solution is obtained.For the convertible bond with call provision,the price of bond is categorized into three classes based on the range of coupon rate,and then three equations can be explicitly solved.Results show that the price of convertible bond with default risk is consistent with that without default risk,regardless of call provision.