Abstract:To overcome the difficulty of constructing complex electromechanical products' reliability mathematical model, a modeling method which combined function-motion-action(FMA) decomposition withfault tree analysis (FTA) was introduced, reducing the difficulty in constructing the reliability optimization modelThen the hybrid GA-PSO algorithm was put forward for solving the problem of trapping in local optimum easily of genetic algorithm(GA) and weak global search capability of particle swarm optimization (PSO). Through the analysis of grinding machine, it is proved that the optimization model constructed by FMA-FTA is feasible and the optimization result of GA-PSO algorithm is effective.

Abstract:The geometrical structure of solar receiver and reactor directly influences the heat transfer characteristics and chemical reaction process,The use of optical characteristics to produce high intensity radiation flux is a common method of building high temperature. In this research, a high temperature reactor based on parabolic dish solar receiver is constructed, which is divided into preheating zone and porous reaction zone. A three-dimensional numerical model of parabolic dish solar receiver and reactor is built by COMSOL Metaphysics software to analyze the distribution law of heat flux in coke plane, the velocity and temperature distribution of reactor under typical operating conditions (DNI=800W/m2), and the influence of reaction fluid inlet velocity and DNI on heat transfer characteristics of reactor. The results will help to explore the efficient use of solar energy and high temperature chemical reactions.

Abstract:With great development of wind power in recent years, it is a trend that doubly-fed induction generators (DFIGs) and permanent magnet synchronous generators (PMSGs) operate together in one wind farm. Because of the differences between transient characteristics of the DFIG and PMSG, the short-circuit current of DFIG could be affected by the PMSG. The short-circuit current of whole hybrid wind farm can not be calculated accurately. In this paper, fundamental-frequency fault model of hybrid wind farm consisting of DFIGs and PMSGs is built. The short-circuit current of the DFIG considering the influence of multiple different wind turbines is deduced. Based on the comparison with short-circuit current of single DFIG, factors and change law of short-circuit currents of DFIG in hybrid wind farm are analyzed and summarized. Short-circuit currents of DFIG under different conditions are analyzed and verified by time domain simulations.

Abstract:In-depth study of the driving behavior and characteristics of drivers is of great significance in promoting the development of intelligent vehicle to highly automatic drive. The application of driving simulator to the study of the driver's driving decision and driving behavior in complex traffic scenarios has become a research hotspot in recent years. Based on the unreal engine 4(UE4) interactive scene simulation technology, we built a driving simulation environment with many traffic elements such as vehicles, roads, buildings, traffic lights, pedestrians, road signs, etc. and designed the high-fidelity and human-machine interactive driving simulation system of Logitech G29 force feedback steering wheel pedal set with CarSim vehicle dynamics model. With the driving simulation system, driving simulation experiments were conducted under typical traffic scenarios and driver's information and real-time driving data were collected to study driving behavior and characteristics. The results show that by the driving simulator a realistic driving experience can be got. Based on Fuzzy C-means clustering algorithm (FCM), the driver characteristics are classified accurately into six clusters, the driver behavior and driving style can be analyzed, and thus the association between driver characteristics and driving capacity are established. An effective way is provided for further research on the allocation of driving rights concerning real-time driving ability.

Abstract:A cooperative adaptive cruise control algorithm is designed for commercial semi-trailers' platoon based on sliding mode control theory. Two inter-vehicle communication modes, the communication between adjacent vehicles and that between leading vehicle and following vehicles, are adopted for longitudinal motion control of commercial semi-trailers' platoon. Then, the performance of the designed controller is illustrated and compared with computer simulations using MATLAB and TruckSim software. Simulation results showthat, compared with the communication between adjacent vehicles, the communication between leading vehicle and following vehicles can reduce the response time and the inter-vehicle space effectively. Besides, it can increase the stability and safety of semi-trailers' platoon, improving the traffic capacity.

Abstract:Based on SMW engineering method, a new HCMW engineering method for foundation supporting was developed, with the advantages of good anti-bending ability, strong watertight sealing, smaller surrounding soil disturbance. Based on the engineering practice, this paper studies the supporting law and effect of HCMW method in the aspects of working condition mechanics analysis, surface settlement, anti-overturning stability, overall stability, heave resistance stability coefficient and so on. The result shows that the horizontal displacement of supporting structure has been significantly changed after bracing, with a gradually decreasing trend from the surface to the bottom of the pit. With the soil's unloading in the excavation area, collateral supporting soil pressure decreases, resulting in a decrease in the displacement of the soil in the lower part of the foundation pit, which generally occurs between 0 and 2 m from the bottom of the pit. The total settlements around the foundation pit and their distance from pit rim present a parabolic shape. The maximum settlement is 18mm, which occurs 5.6m away from the pit rim; the anti-overturning stability, overall stability and heave resistance stability coefficient of the foundation pit are calculated, the homologous values being 1.974, 1.386 and 2.793, which are all greater than the standard safety factors in the specification and meet the safety requirements, indicating that the HCMW method has a better supporting effect.

Abstract:For large SDN networks, the placement and application of multiple controllers is in urgent need. A multi-controller placement approach based on bat algorithm was proposed, and three indexes were optimized, which minimized the average control delay and the controller's load difference, and remove the isolated nodes. The minimization of average control delay was realized when the average control was continuously optimized during one iteration, and the load balance was guaranteed by limiting the load utilization of the controller. At the same time, the tag delivery algorithm was used to remove the isolated nodes to ensure the intra-domain communication. The simulation results show that this approach can guarantee that SDN network achieves small delay and load balanced multi-controller placement without isolated nodes.

Abstract:There are some problems in person reidentification, such as less training samples, no-linear relationship of samples, low recognition ratio. In order to solve these problems, the regularized linear discriminant analysis person reidentification algorithm (KRLDA) based on chi square kernel was proposed. Firstly, the algorithm mapped linear inseparable input data into a high dimensional linear separable feature space using kernel function to obtain scatter matrix that describes adjacent data relationship. Then, regularized linear discriminant analysis was applied to obtain low dimensional projection matrix for maintaining high dimensional separability characteristics to improve the recognition rate of the pedestrian re-recognition algorithm. Finally, experimental results on VIPeR, iLIDS, CAVIAR and 3DPeS datasets show that the proposed algorithm has a high recognition rate and the algorithm based on chi square kernel function has higher recognition rate than other kernel functions.

Abstract:In view of the fact that the study of the positive ideology propagation rarely takes into account of the dynamic model, we built the positive ideology propagation model based on forgetting mechanism. By using the Hurwitz criterion, Lyapunov stability theorem and LaSalle invariance principle, the local stability and global stability of the equilibrium points of ideology propagation were analyzed. The relationship between the propagation threshold and forgetting/cotact rate of influence factors of ideology propagation was obtained. The simulation results show that the range of ideology propagation will be expanded when the rate of forgetting reduces or the contact rate increases. That is to say, the spread range is negatively correlated with the forgetting rate and positively correlated with the contact rate, respectively.

Abstract:To address the security problem of user privacy leak in the data acquisition and monitoring of smart grid, noise is usually added to achieve privacy protection. In this paper, a Laplacian noise algorithm based on multidimensional decomposition(MDLN) is proposed. The algorithm decomposes the original measured value into multidimensional data, and adaptively determines the Laplacian noise amplitude to be added according to the sensitivity of each dimension, achieving differential privacy by effective noise perturbation. The simulation results show that the MDLN algorithm has higher privacy protection and higher performance compared with the SLN(simple Laplacian noise algorithm) algorithm and ULN(uniform Laplacian noise algorithm) algorithm.

Abstract:The continuous girder bridge with new high piers of Concrete Filled Steel Tubular (CFST) laced column has a broad prospect in the construction of bridges in earthquake area. Based on the engineering background of Gan haizi super-large bridge, 34 finite element models of three span continuous bridge were built by universal program of Midas Civil, with different structure design parameters including the pier height, longitudinal slope, axial compression ratio, diameter ratio of lacing tubes and longitudinal tubes, vertical spacing of flat lacing tubes, steel ratio of longitudinal element, number of bracing element, pier top spacing and section form of longitudinal element etc, and the influence of structural parameters on seismic performance of continuous girder bridge with high piers of CFST laced column and the application scope of these parameters were researched through elastic seismic response analysis on E1 earthquake. Then, optimum design of bridge was carried out on the base of numerical results, and calculation results indicated that seismic response of optimized model reduced greatly.

Abstract:In order to study the penetration speed of large-diameter steel pipe pile driven by vibratory hammers, finite element model was established by using the commercial code ABAQUS and the penetration speed, penetration resistance and the ratio of static load force to dynamic load force were analyzed. The results indicated that the hysteresis loops of the pipe pile shaft soil are presented as the banana-shaped curve, which shows the soil experiences two phases of dilation and two phases of contraction during each cycle. The hysteresis loops of the pipe pile end soil are presented as the butterfly-shaped curve, which shows the soil experiences compression phase and stretch phase. The process of pipe pile penetrating by high-frequency vibration can be divided into two stages:slow and fast penetration. Consideration should be given to the static load and dynamic load amplitude coupling relationship.