Abstract:CFD (computation fluid dynamics) was applied to simulate the vehicle windshield defrosting process. To solve the problem of slow defrosting in area A, a new method was proposed. Four defroster grilles were installed at airflow vents, which can rotate around their center axis. Combined with dynamic mesh, the transient defrosting process was calculated. The results show that, when grilles are deflected to 42 degrees, the Nusselt number of area A improves by 13.7%, making the grilles rotate at 0.0733 rad/s, and the grilles are back to the original position at 280s. Compared with the original model, the time required to defrost area A decreases by 60s. The frost covering area A is removed preferentially, which ensures that the driver's field of vision is clear and quick.

Abstract:For the problem of the optimal shelter posture of dish solar concentrator, the flow fluid model of a dish solar concentrator was established by using fluid control equations, the calculated flow velocity and pressure were then loaded into the front and back surfaces of the dish solar concentrator, and then simulation analysis of the aerodynamic characteristics and pressure distribution of dish solar concentrator was carried out. The results show that wind speed has great influence on the maximum pressure of the central area of the dish solar concentrator surface and the strength and rigidity at the center of the dish solar concentrator should be improved. Besides, the lift force, drag force, lateral force and maximum surface pressure of the dish solar concentrator increase with the increase of wind speed, especially the maximum surface pressure, while wind coefficients change little with the change of wind speed. In addition, relatively big errors exist in the calculated values of lift force coefficient, drag coefficient, lateral force coefficient and maximum surface pressure when not considering the effect of fluid-structure interaction. Moreover, the maximum surface pressure of dish solar concentrator varies intricately with change of azimuth angle, and elevation angle and it reaches to maximum when the elevation angle is 0° and the azimuth angle is 45°.

Abstract:Some problems hinder the achievement of information traceability management in the process of construction machinery remanufacturing, which are the complexity of tracing process and the difficulty of effectively integrating material relationship and information of manufacturing process. Based on the activity-based bill of material，a tracing method was proposed, and the tracing model for the process of construction machinery remanufacturing was built. In this model, the traceability entity of the remanufacturing process was divided into three classes: product, operation and activity, which were described with "Backus-Naur Form". An information model for the process of construction machinery remanufacturing was established, while a tracing model was built by using symbolic traceable activity chain and network. The material relationship and information of manufacturing were effectively integrated with the activity-based bill of material, and the tracing process was also simplified with the tracing model.

Abstract:Based on the dynamic theory of multi-body system, a multi-rigid-body dynamic model, which contains the transmission system and structure system of marine gear device, was established by taking account of the internal excitations such as the time-varying mesh stiffness, tooth backlash and bearing stiffness and the external torque excitation caused by the propeller. Then, the dynamic meshing forces of gear pairs and bearing reaction forces were calculated. Using the modal superposition method, the dynamic response of housing surface was solved after the multi-flexible-body dynamic model was developed on the basis of the flexible gearbox and pedestal. Afterwards, a strongly vibro-acoustic coupled model of this gearbox was built by employing the frequency histories of bearing reaction forces obtained from the multi-body dynamics analysis, and the surface sound pressure of gearbox and the radiation noise of outer sound field were calculated. The results show that the peaks of dynamic meshing forces, reaction forces of bearings and dynamic responses of gearbox appear at the position of mesh frequency and its multiples of gear pairs, and the simulation results of vibration acceleration of gearbox and the radiation noise of outer sound field are in good agreement with the experiment results measured in the vibration and noise test platform of the gearbox.

Abstract:The steering resistance torque decreases dramatically on low friction coefficient roads. It leads to the decrease of the steering torque, which can influence the road feel of drivers to a large extent and cause accidents easily. To address this problem, a current compensation control strategy was proposed to improve the road feel of drivers. Extended Kalman Filter method was used to estimate the lateral force of front axle on low friction coefficient roads. Based on the estimated lateral force, the compensation current was calculated correspondingly. Moreover, the simulation model was built in MATLAB/Simulink, and it was validated by comparing the data of real car experiment with model simulation. Finally, simulation results of different driving conditions show that the steering wheel torque is significantly improved so that the road feel on low friction coefficient roads is equal to that on normal roads by using the proposed control strategy, which can effectively prevent driver's maloperation and improve driving safety.

Abstract:For the coolant pump working in high temperature, high pressure and high radiation for a long time in hostile work environment, and its concurrent fault in high probability, a method of DSmT on Decision Level was provided to solve main coolant pump concurrent fault diagnosis problems, and a DSmT identification theory frame for pump rotor imbalance, pump rotor misalignment and spindle damage was built. Then, by using actual measurement data synthetically, DSmT fault features reliability assignment was determined by judging multiple independent evidence sources by DSmT, and then, the diagnosis of main coolant pump failure and its concurrent fault was calculated. The experiment results show that the proposed method can effectively identify the main coolant pump concurrent fault characteristics, and it has some theoretical and engineering application value.

Abstract:As the instantaneous flow of bulk materials is hard to be accurately measured at a high speed on a large capacity belt conveyor in real-time, a more positive and accurate method to measure the material instantaneous flow on belt conveyor based on laser scanning technology was proposed. When the 3D laser point cloud data of bulk materials' surface profile are acquired at high speed by using 2D laser rangefinder and conveyor speed sensor, preprocessing steps of filtering, outliers excluding and data smoothing are applied. Then an automatic contour extraction method was proposed by analyzing the space morphological characteristics of material flow outline's laser point. By integrating the element area of material cross section, a mathematical model to calculate the instantaneous flow of bulk materials on belt conveyors was established. When measuring a trough belt conveyor whose belt speed is at 0.5 m/s to 2 m/s and bandwidth is 200 mm by using our laser scanning measurement system, the data repeatability and correlation can reach above 98%. Experiment results show that this method has strong applicability and reliability due to its small sample spacing, high measuring accuracy and real-time performance. The acquirement of real-time and accurate data can offer convenience for the further research of energy-saving control technology of belt conveyor in bulk terminal.

Abstract:Injury of the lower limb is one of the most common injuries in vehicle-to-pedestrian crashes. Therefore, accurate Finite Element (FE) models of pedestrian lower limb with high biofidelity play an important role in developing effective research techniques for the protection of the lower limb. The models of lower limb long bones (femur, tibia, and fibula), knee ligaments (ACL, PCL, MCL, LCL) and knee joint were fully validated in previous studies. On that basis, FE model of pedestrian lower limb, including skeletons, ligaments, muscles and skins, was developed, and contact properties among different tissues were defined. Based on the biomechanical experiments conducted by Kajzer et al., the FE model was validated against the whole pedestrian lower limb bending tests. The results have indicated that the injury types, injury occurring moments, knee joint bending moments and bending angles of the lower limb FE model are consistent with the experiment data. This model is capable of accurately reflecting the pedestrian lower limb injuries and biomechanical responses in impact processes with higher biofidelity.

Abstract:The characteristic of phononic crystals local resonance was applied to beam to form a local resonat beam. Based on local resonant beam, and by introducing analogy lattice parameter mismatch, a local resonance model of detuning beam was obtained. Through sine excitation response analysis and frequency response analysis of local resonance periodic beam and detuning beam respectively, and combined with the improved energy method, it can be concluded that, by choosing the appropriate detuning parameters，detuning beam is better than periodic beam in the characteristics of vibration reduction.

Abstract:Micro-damage is always unavoidably incurred in structure in fabrication and serving performance. It is of high value to develop an undamaged detection method for these structures. Based on the multi-DOF vibration of mechanics and continuum damage theory, strain-mode based undamaged detection method was discussed and applied in the undamaged detection of composite beam. The strain response of the damaged laminated composite beam at different tested points was obtained through the dynamic test of the structures. And the strain-model curves of the damage structures was acquired by dealing with the dates with the MATLAB programs. The result indicates the exact position of the damage in the structure, which proves the validity of the strain-model method on the damage detection of the laminated composite structure. At last, the model analysis was conducted by applying continuum damage theory based on finite element software ABAQUS, which further demonstrates the feasibility and reliability of the strain-mode method in predicting the damage of structure.

Abstract:The short-circuit impedances of multi-winding transformers vary in different short-circuit states, which are called composite short-circuit impedances. With different short-circuit states, the circulating currents of the windings are different. It takes a long time to solve the composite short-circuit impedance and the circulating current, and there are some difficulties in solving the formulas of the transformer. Aiming at the problems above, a new calculation based on a new field-circuit coupling method was provided. By building the simplified magnetic field model, the inductance matrix of all the transformer windings was obtained. The external circuit and the inductance matrix were combined, and the composite short-circuit impedances and the circulating currents of the multi-winding transformer can be obtained quickly. Taking a 8-winding transformer for instance, the measurement results show that this new calculation method is of high accuracy, low consuming time and high engineering value.

Abstract:To solve the problem of high missing rate and complicated operation in the detection methods of faulty insulator, this paper proposed a new method to automatically extract the disks and steel caps area of insulator from infrared image: via infrared image preprocessing, feature extraction, angle correction and regional extraction to achieve the purpose. This method first makes gray scene processing of insulator infrared image, noise reduction and binarization; then extracts the feature set related to insulator from the binary image to correct the angle of the binary image; finally extracts the disks and steel caps area through the specific algorithm of regional extraction. By extracting the absolute temperature region, texture and relative temperature difference as the insulator state recognition feature set, and the information obtained by measuring the voltage distribution of insulator state as output vector, the model was optimized by training. And the 220kV experiment confirms the validity and usefulness of the method.

Abstract:Based on the distribution of measurement, a Non-Gaussian model of narrow-band power line noise including background noise and impulsive noise was derived, The background noise, which follows Gaussian distributions, was modeled with a raised cosine roll-off filter, while the impulsive noise was modeled with impulse width, interarrival times and envelope parameters, whose distribution follows partitioned Markov chain. Then, the model was evaluated with some field measurement data and the Markov Chain Monte Carlo (MCMC) analysis. The evaluation results show that the proposed model can approximate the noise in real environment.

Abstract:Air side heat transfer and fluid flow characteristics of designed heat exchanger with bridge type fin were studied experimentally. The heat transfer and friction factor correlations were obtained in the experimental range of Reynolds number by processing a large number of experimental data. The experimental result shows that the heat exchanger with bridge type fin has greater heat transfer performance than the straight-fin heat exchanger under the same pump. At the same time， the air-side temperature and velocity field of these two kind fins were simulated by numerical method， and the results were analyzed by the field synergy theory， which shows that the heat transfer enhancement of bridge-type fins is caused by the improvement of the synergy between the velocity field and the temperature gradient.

Abstract:In order to estimate the state of health (SOH) of single cell in battery pack, this paper researched on the battery’s polarization resistance and the Ohmic resistance emphatically. An evaluation methodology of the single cell’s relative SOH was proposed on the basis of battery’s internal resistance, and the SOH of single cell was evaluated using the terminal voltage combining with the internal resistance’s effect on terminal voltage under working condition. and the result analysis of comparative experiment verified that the proposed method had high accuracy and effectiveness.

Abstract:The social networks formed by distributed multi-Agent always show different characteristics. This paper proposed a social networks oriented collaboration degree based negotiation coalition formation mechanism aiming at the heterogeneity of different social networks and multi-Agent. This mechanism established a distributed negotiation protocol and designed a collaboration degree based negotiation tactic, which considered the characteristics of the social networks and the heterogeneity of the Agent. The experiment results in fully-connected network, hierarchical network and small world network have shown that this mechanism can form coalition in distributed environment effectively and show a better performance than other social networks in responding to small world networks in practical environment.

Abstract:FDR codes can compress test stimuli data effectively. However, the number of faults detected by a test pattern is small in average, since don't care bits in the test set are filled by all 0s. The test quality is low. In order to improve the test quality and further increase the test compression ratio, this paper, based on FDR codes, proposed a scheme in which the test response of the previous test pattern is utilized to fill the don't care bits in the current test pattern. This scheme increases the randomness of the X-filling. Therefore, the test quality is improved. In this scheme, the test compression ratio is also related to the order of test patterns. This paper also proposed a test pattern reordering approach based on the nearest neighbor algorithm to decrease the number of conflict bits between the test response of the previous test pattern and the current test pattern. Difference vectors can be obtained by the difference between test patterns and the test responses of their previous test patterns. The test data volume can be reduced by using FDR codes for the difference vectors. Experiment results show that, for larger ISCAS'89 circuits, the proposed approach increases the test quality by 5.9% and test compression ratio by 2.5% in average, compared with those of FDR codes. The hardware overhead, which is only an XOR gate, can be omitted.

Abstract:The characteristics of tile self-assembly model are nanoscale properties, self-assembly, programmable and so on, so it has a great advantage in solving NP problems. This paper proposed a new tile self-assembly model for maximum matching problem. The new model is composed of initial configuration subsystem, choosing subsystem and detecting subsystem. In the new model DNA tiles were designed to store the information. The solution space of maximum matching problem was generated through the assembly operation. Lastly, the answers were found out by the detecting tiles. The performance of the algorithm was also analyzed in terms of the assembly time, the computation space and the types of the tiles, and the algorithm was simulated to prove its effectiveness and correctness.

Abstract:An improved algorithm in WSN hierarchical routing protocols was put forward, which considered the residual energy of cluster head selection and multi-hop data transmission from cluster heads to the sink node, to solve the problems of some cluster heads' premature depletion, which affect the whole life of the network, caused by part of the cluster heads over long distances with single hop data transmission to the sink node. Analyses and the simulations were conducted on the first node's death round number and the energy image.The results show that the improved algorithm can balance the network load better and extend the whole network life, compared with the traditional algorithms.

Abstract:The existing reflection components separation methods can not remove the specularity of natural images without estimating illumination chromaticity. To solve this problem, a cross channel gradient coherence based reflection components separation method was proposed. Firstly, homogeneous specular pixels, which consist of major portion of specular regions, were detected by using cross channel gradient coherence, and the reflection components separation tensor was constructed. Then, the reflection components separation tensor was applied to transform the image gradient, which led to the separation of the specular reflection gradient and the diffuse reflection gradient. Finally, the estimated diffuse reflection component could be reconstructed from the diffuse reflection gradient. Experiment results show that the proposed method separates reflection components for natural images without color constancy preprocessing, simplifies the specularity removal process for natural images, and removes specularity for normalized images more accurately.

Abstract:K-ary N-cube is a widely used network architecture for high performance computer. Uniform stride communication is one of the most important communication models for high performance computing. This paper gave the theoretical lowest limit performance of uniform stride communication in K-ary N-cubeand and achieved a series of performance simulations in a self-developed network simulator. The simulation parameters include network arrays, stride values and message lengths. We also simulated and analyzed two optimized methods, node remapping and message division. As a result, 4-ary N-cube has very good All-to-all performance that approaches the performance of K-ary N-tree, which has the best All-to-all performance.