Table of Content

28 December 2008, Volume 42 Issue 12 Previous Issue    Next Issue

Automation Technique, Computer Technology

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yo-yo Motion Control by Oscillatory Neural Networks JIN Hui-liang,YUAN De-hu,YE Qian,XIE Wen-hua 2008, 42 (12):  1939-1942.  Abstract ( 3737 )   Save Based on various coupling forms of oscillatory neural networks, a simple iPLL (inhibitory phaselocked loop) oscillator was proposed to control the motion of a yoyo. The proposed control has been successfully implemented. The experimental results show that closedloop control of yoyo motion with iPLL is possible. This provides a modelfree alternative to the modelbased control of such tasks. Related Articles | Metrics

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A Hard Accelerated Algorithm for EWA Splatting Based on Modern GPU QIN Hong-xing,YANG Jie,GUO Lü, TANG Wei 2008, 42 (12):  1943-1946.  Abstract ( 3926 )   Save This paper proposed an accelerated algorithm for EWA volume Splatting based on modern graphic processing unit (GPU). It mainly made use of point sprite, frame buffer object and programmable function of GPU. In the algorithm, sampling points are directly regarded as proxy geometry, three dimension texture coordinates at pixels are computed by ray tracing in GPU and Gaussian filter is replaced by an approximate filter.The experimental results demonstrate that the algorithm can be used in high quality and interactive visualization. Related Articles | Metrics

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Design of Modular Layouts for Workshops Based on Sequence Analysis ZHOU Jin1，WU Zhi-ming2 2008, 42 (12):  1947-1952.  Abstract ( 3276 )   Save In a fabricationbased assembly workshop, the material flow network in the facility is obtained by merging the routings of all the parts and subassemblies into a precedence hierarchy known as an operations process chart (OPC) in literature, which inherently possesses a graph structure called a directed intree. This paper describes an algorithmic method for the design of workshop layouts that have such a hierarchical directed graph (digraph) representation of their material flows, including a tree manipulation algorithm and a sequence clustering algorithm to form layout modules. Its application in an industrial case study demonstrates the validation of this method. Related Articles | Metrics

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A WorkinProcess Estimation Method Based on Bottleneck Machines’ Process Time Variability JIANG Shu-yu,ZHOU Bing-hai 2008, 42 (12):  1953-1957.  Abstract ( 3735 )   Save The minimization of cycle time (CT) and the maximization of throughput rate (TH) are the primary goals of semiconductor wafer manufacturing systems. A heuristic algorithm based on the CONWIP release control policy and G/G/m queueing network model was developed. The algorithm aims at calculating a suitable workinprocess (WIP) level in a semiconductor wafer manufacturing system, and considers the factors that cause the bottleneck machines to depart from regular, predictable process time (bottleneck machines’ process time variability). The results of simulation experiments indicate that, fixing the WIP level calculated by the proposed algorithm in the system can achieve a good combination of CT and TH within a certain scope of bottleneck machines’ process time variability. Related Articles | Metrics

Electrotechnology

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Joint Equilibrium in Wholesale Electricity Market and Retail Market SONG Yi-qun，ZHANG Wei-wen，JIN Lei 2008, 42 (12):  2006-2009.  Abstract ( 3237 )   Save Based on the electricity demand characteristics in deregulated retail market, a joint equilibrium model in both wholesale electricity market and retail market was proposed. It is used to illustrate the effect of deregulation in electricity retail market on wholesale spot market. According to the demand load profile, different relationships between retail price were wholesale spot price were simulated for peak load period and valley load period respectively. Then, the joint equilibria in both wholesale electricity market were retail market were derived under completely deregulated retail market and partly retailside regulation. The numerical result shows the effectiveness of the proposed model. It points out that deregulation of retail market will reduce the total electricity demand, decrease the spot market clearing price, and make the electricity demand more elastic. It also can be concluded that more competitive the retail market is, less effect of fixed retail price but larger effect of demand elasticity will be on the spot market clearing price. Related Articles | Metrics

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Design of HVDC Supplementary Controller Based on Frequency Scanning Method YANG Fan1,PENG Bo2，CHEN Chen1,WANG Xi-tian1, XU Yingxin1,SHI Huijie1,SHEN Liang1 2008, 42 (12):  2010-2014.  Abstract ( 3487 )   Save The concept of complex torque coefficient was extended to the design of HVDC supplementary controller. By scanning the AC/DC system in low frequency band, the frequency domain characteristics of controller were derived, which should satisfy the desired performance and stabilize the system. Setting the frequency domain characteristics as constraint conditions, the structure and the parameters of the controller can be determined. The index curves obtained are visible and intuitional, easy to analyze the effects of system parameter variations on the controller performance, and helpful to gain the robust controller. In the twoarea fourmachine system of the case study, the results show that under various operation conditions, the supplementary controller can damp out the low frequency oscillations. Related Articles | Metrics

Mathematics

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The New Formulas of Simultaneously Calculating DFT of Real Sequence and IDFT of the DFT of Real Sequence FAN An-dong 2008, 42 (12):  2052-2055.  Abstract ( 3711 )   Save By analyzing some properties of discrete Fourier transform (DFT), exploiting the symmetries of DFT and decomposing a complex sequence into four sequences, a few mistakes in the direct formulas for simultaneously calculating the DFTs of two real sequences and the DFT & inverse discrete Fourier transform (IDFT) of real sequences which were proposed by Gunther were corrected, the new direct formulas of simultaneously calculating DFT of a real sequence and IDFT of the DFT of another real sequence were proposed and proved. Related Articles | Metrics

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The Strong Deviation Theorem in Series Investment Modeling BAI Yun-fen1,2，YE Zhong-xing1 2008, 42 (12):  2056-2059.  Abstract ( 3168 )   Save Using the properties of submartingales, this paper obtained a strong deviation theorem about the limit properties of return rate when there are deviations between the estimated and the real distributions of the return rate. The conclusions are represented by inequalities. Related Articles | Metrics

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On the Two Kinds of Depth Distribution over F2 ZENG Min1,2,3,LUO Yuan1 2008, 42 (12):  2060-2064.  Abstract ( 3155 )   Save An expression of the second depth distribution of ndimensional vector space over F2 was presented. For the third depth distribution, the integral result was given directly. Related Articles | Metrics