Abstract:By taking the longitudinal control model （LCM） as the basic car-following model，the car-following behavior is modeled based on the uncertainty of driver distance perception. It is assumed that the error of perceptual spacing follows the uniform distribution and the truncated normal distribution. Thereafter， the relationships between the probability density function parameters （i.e. the boundary values of the uniform distribution， the mean value and standard deviation of the normal distribution） and the factors （i.e. observed spacing values and driver’s aggressiveness characteristics） are established. Then，the extended model based on the uniform distribution and the extended model based on the truncated normal distribution are obtained.Finally， the Shanghai naturalistic driving data are employed to calibrate the extended models. It is shown that the extended models exhibit better performance than LCM， indicating that the extended models could capture the uncertainty of driver distance perception. Besides，the extended model based on the truncated normal distribution has better performance than the extended model based on the uniform distribution.

Abstract:Seven typical car-following models under different mechanisms， including microscopic traffic simulator（MITSIM）、Gipps model、Wiedemann model、full velocity difference（FVD） model、intelligent driver model（IDM）、S-K model and longitudinal control model（LCM）， were tested under seven designed driving regimes. It is shown that each model is able to complete three free flow regimes to a certain extent， and the performance of LCM is consistent with the cognition rather than the other models. IDM has the smallest value of acceleration and the longest acceleration process. Only Gipps model， FVD model， IDM， and S-K model are able to complete four car-following regimes， among which FVD model has the most timely response to the state change of preceding vehicle. The speed and acceleration of S-K model are always in a slight oscillation under seven driving regimes， which is in line with the actual driving situation.

Abstract:Based on the time-dependent proportional-hazards regression model， factors affecting lane-changing duration（LCD） are studied. Five hundred and sixty complete lane-changing （LC） trajectories are extracted from the newly opened HighD dataset， and the overall distribution of lane-changing duration is estimated using the non-parametric estimator. Then， the time-dependent proportional-hazards regression model is introduced to analyze the factors affecting LCD. It is found that most drivers finish LC in 3?8 s. There are six variables， of which the most important one is current vehicle’s speed. Additionally， the preceding vehicle in current lane and the following vehicle in target lane have significant effects on LCD.

Abstract:A two-stage method of traffic conflict analysis was proposed based on risk region. By using the inD dataset， traffic conflicts were recognized with the calculation of time to risk region（t_TTR）， and then the degree of traffic conflict risk was judged by risk region duration. Compared with the method based on time-to-collision（t_TTC）， the proposed method can not only identify rear-end conflicts and crossing conflicts more effectively， but also characterize the degree of traffic conflict risk at different times.

Abstract:A modeling method of dynamic graph hybrid automata combined with an improved cell transmission model was proposed. Based on the triangular fundamental diagram fitting results of flow volume and density of road segment under different mixing ratios of automated driving vehicles， the variation rules of critical congestion density， traffic capacity， reverse wave velocity and other main parameters were discussed， and the traditional cell transmission model was improved. The dynamic graph hybrid automata was used to characterize the hierarchical topology of road network， and the improved cell transmission model was embedded into the dynamic graph hybrid automata to establish a macroscopic traffic flow model under heterogeneous traffic condition. Finally， simulation platform was built by using the OpenModelica software to verify the effectiveness of the modeling method. The results show that with the increase of the mixing ratio of automated driving vehicles， the critical congestion density， maximum traffic capacity and reverse wave velocity of road segment all have significant changes.

Abstract:In this paper， the vehicle model based on SUMO is optimized by using real vehicle parameters and actual road test data. Then， a high fidelity vehicle operation characteristic model with the ability of automatic driving full working condition test is built. Integrated with SUMO traffic flow simulation， a hybrid heterogeneous traffic flow simulation platform is set up. Finally， the accuracy and availability of integration effect are verified by typical traffic operation scenarios.

Abstract:Concrete-concrete interface is commonly found in concrete structures. The shear resistance of the concrete-concrete interface is the basis for ensuring the integrity of different concrete parts in the structure. In this paper， we introduce the shear transfer mechanism， the design expression of shear stress， the bond behavior of the concrete-concrete interface and the factors affecting the behavior of the concrete-concrete interface. Then， we discuss the durability of the concrete-concrete interface. Finally， the conceptual design frame of the concrete-concrete interface is built.

Abstract:A refined model of the shallow cable attached with two dampers（cable-two dampers） ， where one damper （damper Ⅰ） is a viscoelastic damper and the other one （damper Ⅱ） is a high damping rubber （HDR） damper， is established. General frequency formulas of the cable-two dampers system are then obtained. Two long cables of an existing cable-stayed bridge are used for experimental study and field monitoring. The long-term vibration monitoring of the cables with two dampers and with only one viscous-shear damper respectively has shown that the vortex-induced vibrations experienced by the cable only with the viscoelastic damper are successfully mitigated by the additional HDR damper. Besides， field tests on the cable damping before and after the installation of the HDR damper have indicated that the achievable damping ratios for the low-order modes of the cable are consistent with the corresponding theoretical estimates； meanwhile， the existence of the HDR damper somehow decreases the cable damping in low-order modes supplemented by the viscoelastic damper， and the reduction effect is more significant for the first several modes. Moreover， it is theoretically found that the stiffness of the viscoelastic damper helps improve the damping effect of the HDR damper on the high-order modes of the cable.

Abstract:Two direct shear experiments were designed， and the mechanical characteristics of steel keyed joints in the construction and service stage were analyzed with a combination of numerical analysis. It is shown that the joints depend on the contact compression between steel and concrete to transfer the shear force between the joints under the action of confining stress. The joints have high shear bearing capacity and good ductility. When the load-displacement curve enters the horizontal section， the joints can still bear large relative deformation， and its bearing capacity does not decrease. In the construction stage， the inelastic deformation of crossing-joint teeth should be used to control the temporary load design. In the service stage， the direct shear strength of the joints should be controlled by the shear strength of steel key’s material. The direct shear resistance of steel keyed joints can be calculated according to the shear formula. The material of the keys and the diameter of the crossing-joint teeth are the key factors affecting the bearing capacity of the joints.

Abstract:The corrected initial lining permeability coefficient is adopted to characterize the permeability of composite lining. A seepage model of composite lining is established and the correction formula of the permeability coefficient of composite lining is derived. Then， the proposed formula is verified by using the model reduced and numerical method. It is found that： when the rock surrounding permeability coefficient in the range of 1×10^-7??1×10^-6 m·s^-1， with a consideration of drainage pipes， geotextile and waterproof sheet， the effect of the permeability coefficient of composite lining on water inflow and external water pressure should not be ignored； the permeability coefficient of composite lining is closely related to the distance between two circular drainage pipes， the permeability coefficient of initial lining， the inner and outer radius of initial lining， the thickness and the permeability coefficient of geotextile； the larger the distance between two circular drainage pipes， the smaller the permeability coefficient of composite lining.

Abstract:A steel-glulam hybrid reticulated shell structure is adopted in the Chongming Natatorium. Based on the analysis of the mechanical properties of glulam and the static force of the natatorium structure， the reasonable application range of steel and glulam for the reticulated roof is calculated. Then， the effect of the stiffness of steel splint-timber structure connection node on the overall stiffness of the structure is discussed， and the actual stiffness of the node is obtained by node experiments. Referring to “Technical Specification for Spatial Reticulated Structures” on the stability analysis and ultimate bearing capacity calculation method of the reticulated shell structure， due to the material defects and non-plastic development capacity of the timber， the safety factor of elasto-plastic ultimate bearing capacity for the steel-timber hybrid reticulated shell structure is recommended to be 4.2.

Abstract:In this paper， the concept of passive energy district is proposed to build a research framework of urban form and energy consumption under the action of multi-element. By using the multidisciplinary design optimization （MDO） and taking three simulation experiments under Shanghai climate condition as examples， the law of building energy consumption change with urban form elements， including building typology， district capacity， usage pattern， is revealed. Finally， the optimal design strategy of urban spatial form for passive energy district is put forward.

Abstract:A prediction method of urban hourly water demand based on synthetic weight factor is proposed. According to the water consumption data of the days and weeks before the forecasting day， the average hourly water consumption is calculated. Then， the synthetic weight factor is introduced to construct the water consumption model of the day before the forecasting day. Combined with the daily water demand forecasting data， the optimal continuous days， the optimal continuous weeks and the synthetic weight factors are used to forecast the hourly water demand of the forecasting day. The case study shows that the average absolute percentage error of the predicted values is small.

Abstract:Under the limit of car localization sensors such as GPS and Wi-Fi in parking lots and tunnels， an autonomous self-localization method of vehicle based on lidar is proposed. The lidar simultaneous localization and mapping （SLAM） algorithm is used to obtain the estimated pose of vehicle through three-dimensional lidar point cloud matching， and all poses are adjusted according to the graph optimization method and the nonlinear optimization method. Then， a planar grid map of environmental information with controllable resolution is obtained. Based on the Monte Carlo method， a particle filter is adopted for real-time vehicle localization， and an improved method of particle sampling is proposed to achieve real-time high-precision autonomous localization of vehicle. Experimental results show that the particle filter can effectively realize the localization of vehicles in parking lot and other non-GPS environments， and the localization accuracy is within 10 cm.

Abstract:A diesel bus certified to meet China Ⅴ emission standards is selected as the research object to explore the mass， number， size distribution and microscopic morphology of particles by fueled with different used cooking oil （UCO） biodiesel blends during China typical city bus driving cycle （CCBC） experimentally. The results show that the mass and the number of particles emitted from the diesel bus decrease as the mixing ratio of the UCO biodiesel increases， and the typical microscopic morphology of particles by fueled with biodiesel blends is similar to that by fueled with diesel. The particles consist of dozens of quasi-spherical basic carbon particles， mainly in irregular shapes such as chain and branch. Moreover，the particles by fueled with biodiesel blends have smaller basic carbon particle size， larger fractal dimension and more compact spatial structure than those by fueled with diesel. In the process of oxidation， the particles by fueled with biodiesel blends are easier to be oxidated at agglomerating area， and the fractal dimension and the average size of basic carbon particles increase with the oxidation. However， the oxidation mainly occurs at the outermost carbon layer of the particles by fueled with diesel， and the fractal dimension and the average size of basic carbon particles decrease.

Abstract:Gas mixtures with different components and temperatures were used to simulate the exhaust gas of anode and cathode for solid oxide fuel cell （SOFC）. And a double-layer porous medium burner was built to investigate the combustion characteristics of the simulated SOFC exhaust gas. The results show that the burner can realize the stable combustion of anode exhaust gas at the transition and stable stage of SOFC. However， the combustion of anode exhaust gas at the initiating stage is prone to backfire and the flue gas temperature in the burner has a little change with the SOFC working stage. The decrease of combustible components and the increase of inert components in anode exhaust gas make the flame move downstream in the burner and reduce the stable combustion temperature. Decreasing the inlet air velocity makes the stable combustion temperature rise first but then drop and the flame move upstream in the burner. Under the condition of no back pressure， the stable combustion limit of the burner decreases with the increase of fuel utilization.

Abstract:By taking a certain type of excavator as the research object， a working device is set up and a mathematical model of digging resistance is established. Firstly， the pressure and the displacement of each cylinder during excavation are tested by pressure sensor and displacement sensor， and the stress of the boom and arm at each measuring point is measured by resistance strain gauge in the working conditions of soil and stone excavation. Secondly， the loads are calculated by dynamic analysis based on the displacement and pressure of each cylinder. Finally， the rigid-flexible coupling model of the excavator is built by using finite element software and dynamic simulation software. Driven by the displacement curve of each cylinder， the stress of the boom and arm at each measuring point is obtained. It is shown that simulation results and test results of the stress have the same trend， and the error is less than 15%.