Key Engineering Materials Vols. 439-440

Abstract: Combining cerebella model articulation controller with sliding mode control, a novel control algorithm is designed. It adopts neuron PID controller as the teacher signal of CMAC. The control error rapidly tends to zero by adjusting weight of each corresponding unit in CMAC storage. The control algorithm eliminates the chattering in the conventional sliding mode control. It also has high real-time, strong robustness and better convergence. The control algorithm is applied on position servo system of NC machining tool. The experimental results show that it improves dynamic performance and static performance of position servo system. It can realize rapid and exact position servo control of NC machine tool.

Abstract: This paper studied the localization problem for a rescue robot based on laser scan matching and extended Kalman filtering (EKF). Scan matching method based on normal distribution transform (NDT) can avoid hard feature extraction problem by estimation of the probability distribution of laser scan data and localization can be achieved using correlation of the NDT. Based on NDT scan matching, the NDT-EKF algorithm is proposed , which realizes fast and precise localization in rescue environment by fusing odometery data and scan matching together. The NDT-EKF algorithm has been extensively tested and experimental results show its effectiveness and robustness.

Abstract: In order to improve DCSK scheme’s efficiency and robust in multipath channel, a novel multi-bit DCSK system was put forward. The system’s each bit is added to some protecting time space. A number of bits are composed to a frame and differential scheme are adopted in conjoint bits. In the multipath channel the system’s BER was obtained in theory. The results show that compared to DCSK system, it has higher transmission efficiency. It can overcome intra-symbol and inter-symbol interferences induced by multipath effect and capture more multipath energy.

Abstract: This paper introduces the phenomenon of nonlinear chaos of the peak current mode to control H bridge converter that has been known to become chaos for wide parameter variations after simulating to the model of H bridge converter. The natural reason of nonlinear phenomena can be explained by theoretical analysis. According to the characteristics of H bridge converter, resonant parametric perturbation was provided to suppress chaotic behavior of the converter and made the system changing from chaos to stable period. It is an effective non-feedback method for controlling chaos and it is such a suitable control method for controlling chaos in non-autonomous systems. Selecting the best perturbation phase to achieve the best chaos control results can optimize the method of resonant parametric perturbation. The control method suppresses chaos with high efficiency and it can provide theoretical basis for stability design of H bridge converter.

Abstract: This paper analysis the work principle of peak current mode H bridge converter. It can observe the system exhibits a kind of special nonlinear phenomenon: breathing phenomenon. When the disturbance signal frequency is not different with the switching frequency and there is a certain degree of disturbance signal intensity, it will produce breathing phenomenon through the modeling and numerical simulation to the system. We can know the theoretical analysis is same with the numerical simulation. At last, it discusses the change of circuit parameters Iref, E, L / T to impact degree of disturbance signal intensity to generate breathing. It can provide theoretical basis for stability design of H bridge converter.

Abstract: The safety assessment of the production process can provide scientific basis for management decisions. The application of neural network theory in system safety assessment can overcome some traditional deficiencies of traditional safety assessment methods and arrive at accurate assessment result. The paper introduced Genetic Algorithm (GA) into the optimization of BP algorithm, which use GA to optimize the weight and threshold of BP and then utilize BP network to seek for exact solution, so that the target of global optimization and fast efficiency can be achieved. Based on this, the GA optimized neural network was applied in the system safety assessment, and the assessment model based on the algorithm was proposed. The example to verify the effectiveness of GA optimized BP algorithm was also provided.

Abstract: As a general-purpose simulation framework, HLA has been widely used in the field of distributed interactive simulations. Based on the systematical description of three major components of High Level Architecture (HLA) and using a combination way of theory and practice, the paper focused on the application of Federation Development and Execution Process Model (FEDEP) method in tactical communication simulation training federation. Combining with the FEDEP process model, key steps of federation target, conception model, development, integration and test and etc of tactical communication simulation training were designed, which lied good foundation for realization and federation-level reuse of tactical communication simulation training federation.

Abstract: Clustering techniques are often used in Web log mining to analyze user’s interest on the web pages. Based on the analysis of advantages and disadvantages of the application of classic clustering algorithm in Web log data mining, the paper brought out a kind of hierarchical K-means Web log clustering algorithm, which integrated K-means clustering algorithm and cohesion-based hierarchical clustering algorithm and overcame shortcoming of high time complexity of hierarchical clustering algorithm. The clustering effect of the algorithm is better than K-means clustering and fit for clustering process of large amount data. The result analysis of practical Web log data clustering also proves the validity of the algorithm.

Abstract: The traditional plat network design method can not meet the requirements of scale enlarge and performance expansion of network. Based on the analysis of deficient of traditional plat design method and referring to structured system analysis method, the paper brought out a structured network design method and analyzed its advantages. Using OPNET network simulation tool, the scalability of these two design method and performance of the designed networks were analyzed with simulation. The simulation result shows that the structured network design method is superior to plat design method in scalability as well as the overall and local performance of the designed network.

Abstract: Overlap-blur is caused by the relative movement of high speed between the camera and the object during the exposure process, which is one of the most common phenomenons of image degradation during the criminal detection forensics work. Based on the analysis of the overlap-blurred image’s characteristic, a coded-shutter model is proposed to approximate the nature of overlap-blur. As the first attempt, using the coded-shutter model, an image deblurring algorithm is designed for the restoration of the overlap-blurred images. The experiment results show the validity and rationality of the coded-shutter model for deblurring the overlap-blurred images. When tested on the real overlap-blurred photographs, the proposed algorithm can restore the information of interest in the blurred images better, which demonstrates the higher practical value of the algorithm.