Abstract: The power quality has attracted considerable attention from both utilities and users due to the development of sensitive electronic equipment in power system network. A novel method for detecting and localizing power quality disturbance based on wavelet neural network is presented. The wavelet transform is established on decomposition of a signal according to time-scale using basis functions with adaptable scaling properties known as multiresolution analysis. The wavelet transform expands a signal not in terms of a trigonometric polynomial but by wavelets, generated using transition and dilation of a fixed wavelet function. The feature obtained from wavelet transform coefficients are inputted into the neural network for power quality disturbance pattern recognition. The improved network algorithm is utilized to complete the network structure initialization. The fundamental component of the signal is estimated to extract the mixed information using wavelet network, and then the disturbance is acquired by subtracting the fundamental component. The simulation results show that the proposed method is more sensitive to signal singularity, and achieves better performance over traditional method.
Abstract: According to modeling problem for complex systems, a compensatory fuzzy neural network (CFNN) modeling method based on particle swarm clustering is proposed: the particle swarm clustering is used to automatically separate the space of input-output data, obtain the numbers of inference rules of fuzzy model and find fuzzy rules. Based on the rules, we modified fuzzy reasoning process and established initial structure of compensatory fuzzy neural network. Then using adaptive rate algorithm optimized initial network parameters, which can obtain a faster training speed and more precision. Simulation results show that the proposed network has successfully modeled the oxidation decomposition reaction process.
Abstract: Electric power steering (EPS) systems are rapidly replacing existing traditional hydraulic power steering systems due to their important advantages such as fuel and cost savings, environmental compatibility and flexibility. Many articles are available in this field in which EPS is viewed only from one specific aspect. Other aspects have been introduced only by brief equations neglecting some main details regarding the important effects of ignored parts. Therefore, it is quite necessary to make a complete analysis of every part of this system with a right combination between them. It makes a comprehensive simulation system for EPS. This matter needs sufficient knowledge in mechanical, electrical and control sciences and how to assemble them with each other properly. Therefore, Mechatronic is the most appropriate branch of science to achieve this goal. In this paper, a complete model of EPS is presented which includes a 7-D.O.F mechanical model of steering system. A Permanent Magnet Synchronous Machine (PMSM) is used to supply the assist torque to steering column. Vector Control Method is utilized for controlling the motor. A PID controller determines the reference assist torque value. The results are presented to estimate the model precision and evaluation of model.
Abstract: A design method of LS-SVM based stable adaptive controller is proposed for a class of nonlinear continuous systems with unknown nonlinear function in this paper. Due to the fact that the control law is derived based on the Lyapunov stability theory, the scheme can not only solve the tracking problem of this class of nonlinear systems, but also it can guarantee the asymptotic stability of the closed systems, which is superior to many LS-SVM based control schemes. The effectiveness of the proposed scheme is demonstrated by simulation results.
Abstract: As the electronic industry advances rapidly toward automatic manufacturing smaller, faster, and cheaper products, computer vision play more important role in IC packaging technology than before. One of the important tasks of computer vision is finding target position through similarity matching. Similarity matching requires distance computation of feature vectors for each target image. In this paper we propose a projection transform of wavelet coefficient based multi resolution data-structure algorithm for faster template matching, a position sequence of local sharp variation points in such signals is recorded as features. The proposed approach reduces the number of computation by around 70% over multi resolution data structure algorithm. We use the proposed approach to match similarity between wavelet parameters histograms for image matching. It is noticeable that the proposed fast algorithm provides not only the same retrieval results as the exhaustive search, but also a faster searching ability than existing fast algorithms. The proposed approach can be easily combined with existing algorithms for further performance enhancement.
Abstract: According to the phenomenon of falling into local optimum during solving large-scale optimization problems and the shortcomings of poor convergence of Immune Genetic Algorithm, a new kind of probability selection method based on the concentration for the genetic operation is presented. Considering the features of chaos optimization method, such like not requiring the solved problems with continuity or differentiability, which is unlike the conventional method, and also with a solving process within a certain range traverse in order to find the global optimal solution, a kind of Chaos Immune Genetic Algorithm based on Logistic map and Hénon map is proposed. Through the application to TSP problem, the results have showed the superior to other algorithms.
Abstract: Wireless Local Area Networks (WLANs) have been attracted significant research during the last few years. The primary medium access control (MAC) technique of 802.11 is called distributed coordination function (DCF). DCF is a carrier sense multiple access with collision avoidance (CSMA/CA) scheme with binary slotted exponential backoff. This paper proposes a new Markov model to analyze the CSMA/CA protocol and average packet delay. This model covers the finite load condition and saturation condition. The close agreement between the theoretical results and simulation results using NS-2 under reaffirms the accuracy of the analytical model.
Abstract: A two-dimensional density weighted averaging combined ( ) operator is built based on the information aggregation of two-dimensional density weighted averaging ( ) operator. The new operator is applied in the information aggregation of combined evaluation. Then the classifying method of two-dimensional data in combined evaluation is given. Finally, an aggregation example is given.
Abstract: This paper presents a new method to calculate control delay at signalized intersection or other types using speed-time data. For the control delay which composed of deceleration delay, stopped delay, and acceleration delay, it is important to determine the critical points of each delay. This paper uses speed as well as acceleration to determine the critical points and get an accurate result. Different with other researches, it uses the area that composed of real time speed curve and desired speed curve, divided by the downstream speed, to get the control delay precisely. This method needs less data than other methods and can be applied to any traffic condition including variant desired speed or volume. This paper also provides a rapid method, which doesn’t need to determine the critical points, to estimate control delay, and the precision is acceptable.