Table of Content

28 February 2012, Volume 46 Issue 02 Previous Issue    Next Issue

Automation Technique, Computer Technology

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Some Views on Geometry Computing HE Yuan-Jun 2012, 46 (02):  167-171.  Abstract ( 2655 )   Save Discussion for centuries about geometry and algebra was reexamined, problems caused by algebraization of geometry were also analysed. Progress of “geometry problems should be solved geometrically”was explored with angle of human cognition. Common problems of geometry and descriptive geometry are stated. Effects by descriptive geometry theory on geometry computing were discussed. Geometry computing problems were considered under “large geometry” concept formed by geometry and descriptive geometry. From the view of construction, “Geometry quality” and fundamentality of geometry singularity are set forth, key points of geometry computing are seized. When discussing geometry computing, stable juncture (geometry problems should be solved geometrically) should be found based on mathematics (geometry and algebra), engineering (descriptive geometry), computer (algorithm) and so on. A framework of this topic was then built with “primary geometric functions” and “geometric numeric”. Base theory and execution method of geometry computing were established. References | Related Articles | Metrics

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Interference-Free Tool Positioning for Five-Axis Sculptured Surface Machining Using ThirdOrder Point Contact Approach   ZHENG Gang, LU Yao-An, ZHU Li-Min 2012, 46 (02):  172-177.  Abstract ( 2899 )   Save Based on the third-order local approximation of tool envelope surface, an interferencefree tool positioning strategy was proposed for five-axis sculptured surface machining with a constraint on the tool feasibility space. The tool feasibility space is constructed by analyzing the local and global interferences， which is indicated by the distance between the design surface and the tool axis. On this basis, the tool orientations are adjusted and optimized to achieve the optimal contact between the tool envelope surface and the design surface within the computed tool feasibility space. The numerical examples indicate that the proposed method can avoid interferences effectively and improve the machining strip width greatly. References | Related Articles | Metrics

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Robotics Vision-Based System of Autonomous Underwater Vehicle for an Underwater Pipeline Tracker ZENG Wen-Jing, XU Yu-Ru, WAN Lei, ZHANG Tie-Dong 2012, 46 (02):  178-183.  Abstract ( 3760 )   Save The detection and tracking of underwater pipeline based on monocular vision system of AUV(autonomous underwater vehicle) were addressed. An integrated vision system including software and hardware structure was designed. The feature of underwater pipeline image was analyzed and according to that, corresponding preprocessing method was proposed. An improved Hough transforming was advanced to obtain pipeline contour. Pipeline reference zone was estimated to increase the accuracy and decrease the time cost of pipeline tracking. Finally, the system was validated to be effective and feasible through the tank experiments.   References | Related Articles | Metrics

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Research on Long Pipe Effects of Non-magnetic Hydraulic Motor Servo System QU Jin-Chao, WANG Xu-Yong, DAI Yong, TAO Jian-Feng, YANG Fei-Hong 2012, 46 (02):  184-189.  Abstract ( 3355 )   Save Nonmagnetic hydraulic motor servo system requires that servo valve must stay far away from non-magnetic motor since the servo valve will produce electromagnetic interference which can-t be ignored. In order to analyze the long pipe-s influence on the nonmagnetic hydraulic servo system, a mathematical model of valvecontrolled motor servo system based on precise pipe model was developed and simulated. The research results reveal the law of pipe length, pipe diameter and other related parameters affecting on the system and show that long pipe effects will reduce the hydraulic natural frequency and hydraulic damping by a large margin. The experiments verify the above conclusions, and show that threeloop feedback control strategy instead of traditional simple proportionalintegralderivative (PID) control strategy can lower the adverse impacts owing to long pipe to some extent.   References | Related Articles | Metrics

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Docking Control of Underwater Selfreconfigurable Robots LI Jia-Wang, GE Tong, WU Chao, WANG Xu-Yang 2012, 46 (02):  190-194.  Abstract ( 3137 )   Save   This paper discussed the problem of planar docking between two modules of an underwater self-reconfigurable robot(USR). From the relation between the sensors intensity and coordinate errors of the modules, the optimized function ofthe docking problem was presented. Due to the fact that the module-s kinematics is invertible, the docking problem wasseparated into three sub-optimized problems in the directions of x, y and θ respectively. Based on the concept of centering method, the sub-optimized functions in the threedirections were presented, and the docking controllers in these directions were designed. The discrete model of themodule-s inverse kinematics was derived. To increase the precision of computation, a stabilizing discrete scheme wasproposed. The simulation results illustrate and validate the effectiveness of the proposed docking control method.   References | Related Articles | Metrics

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Adaptive S Plane Control for Autonomous Underwater Vehicle LI Yue-Ming, PANG Yong-Jie, WAN Lei 2012, 46 (02):  195-200.  Abstract ( 4265 )   Save (Sigmoid) plane control method is an effective and simple method for the motion control of autonomous underwater vehicle (AUV). A velocity controller was constructed and analyzed by S plane control method. According to sliding mode controller (SMC), an integral S plane velocity controller with selfadapting integration step was proposed in order to make control parameters adjusted by motion state. Then a selfadapting item was improved for eliminating steadystate errors and adjusting dynamically S plane controller locally. Both pool and sea experiment results show that the improved controller is effective and the adaptability of AUV motion control is strengthened largely.   References | Related Articles | Metrics

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Hybrid Position Tracking Control of a Pneumatic Artificial Muscle SHEN Wei-1, SHI Guang-Lin-2 2012, 46 (02):  201-206.  Abstract ( 3330 )   Save   A single degree freedom pneumatic artificial muscle spring mass system was built. The pneumatic artificial muscle is controlled by high speed on/off valve in PWM technique. A hybrid controller is setup to tracking control the pneumatic artificial muscle system which is composed of an adaptive fuzzy CMAC (cerebellar model articulation controller) and discrete sliding mode reaching low strategy. In hybrid controller discrete sliding mode strategy produces the control output; the adaptive fuzzy CMAC is used to approximate the uncertainty of the pneumatic artificial muscle control system. The online self adjustment ability guarantees the approximation ability of the adaptive fuzzy CMAC. Finally, the comparative study of control performance between discrete anti saturation PID (DASPID) and hybrid controller (HybridC) was carried out. The experimental results suggest that the hybridC is better than DASPID. While the desired reference input is sinusoidal, the biggest tracking error of PID is ±15 mm; however the biggest tracking error of the hybridC is only ±07 mm; the average tracking error is about ±02 mm. Furthermore as the main drawback of discrete sliding mode strategy, the chatter phenomenon is greatly reduced.  References | Related Articles | Metrics

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Mobile Robot Self-Localization Based on RFID System with Adaptive Power Control WANG Jing-Chuan, FANG Yi, CHEN Wei-Dong 2012, 46 (02):  207-212.  Abstract ( 3433 )   Save An adaptive power control system for RFID which is applying for mobile robot localization was proposed. The Mahalanobis distance is introduced to particle filter as an evaluation function for particle weight to avoid particle depletion. Meanwhile, an evaluation function for the performance of localization using particle filter was proposed and used to adapt antenna power to the distribution character of tags in a local environment. The experiments show that the proposed method obtains higher and more consistent localization accuracy as well as systems reduced power consumption. References | Related Articles | Metrics

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Obstacle Avoidance Based on Multiple Objective Optimization for Mobile Robots YANG Jing-Dong-1, YANG Jing-Hui-2, CAI Ze-Su-3 2012, 46 (02):  213-216.  Abstract ( 4674 )   Save Obstacle avoidance is an important aspect of navigation for autonomous mobile robots. An efficient algorithm of obstacle avoidance was put forward based on multiple objective optimization (MOO) theory. The algorithm gives how to acquire the efficient solution for mobile robots using the multiple objective optimization theory. The method divides the navigation with the given goal into three subbehaviors, which can be changed dynamically according to the current weighting or priority, in order to acquire the most satisfying path or preferred solution at current time. In the end, the experiment shows that the algorithm can improve the security and smoothness of obstacle avoidance efficiently without sacrificing the robustness of the whole process. References | Related Articles | Metrics

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Design and Analysis of DP-3 Dynamic Positioning Control System Based on Vxworks WANG Fang, WAN Lei, JIANG Da-Peng, XU Yu-Ru 2012, 46 (02):  217-222.  Abstract ( 3505 )   Save To satisfy the increasing demands on the reliability of dynamic positioning system for deepwater oil and gas exploration, a threeredundant dynamic positioning control system was established based on the realtime operating system Vxworks according to the classification specification of class notation DP3 for dynamic positioning system. Hardware architecture of the tripleredundancy control system was designed based on the PC104 bus. Control calculation and faulttolerant management of threeredundant realtime control computers were implemented by software. The reliability of control system was analyzed by using Markov process, and the effects of various hardware fault parameters on the reliability measures were investigated. The analysis results show that the reliability of DP3 dynamic positioning control system can be greatly improved.   References | Related Articles | Metrics

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Calibration of a LargeScale 3D Laser Measurement System GUO Yang-a, DU Zheng-Chun-a, b , YAO Zhen-Qiang-a, b 2012, 46 (02):  223-227.  Abstract ( 2874 )   Save The calibration method of 3D laser scanning measurement system based on the projective geometry transformation was researched. Based on the characteristic of scanning plane and calibration target, the relationship between different coordinates of the scanning points was deduced by projective geometry theory. According to the thought of closed kinematic chain, the constraint equations were established. Hence the calibration problem can be converted into the solution of the intrinsic matrix and the extrinsic matrix of the system parameters in the global coordinate. The calibration was achieved through the above two matrices by spatial transformation. Finally, the validation was verified through the experiments. The research result lays a good foundation of the further work. References | Related Articles | Metrics

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QuantumBehaved Particle Swarm Algorithm with Selfadapting Adjustment of Inertia Weight HUANG Ze-Xia-1, 2 , YU You-Hong-3, HUANG De-Cai-1 2012, 46 (02):  228-232.  Abstract ( 5320 )   Save A new quantumbehaved particle swarm algorithm with selfadapting adjustment of inertia weight was presented to solve the problem that the linearly decreasing weight of the quantumbehaved particle swarm algorithm cannot adapt to the complex and nonlinear optimization process. The evolution speed factor and aggregation degree factor of the swarm are introduced in this new algorithm and the weight is formulated as a function of these two factors according to their impact on the search performance of the swarm. In each iteration process, the weight is changed dynamically based on the current evolution speed factor and aggregation degree factor, which provides the algorithm with effective dynamic adaptability. The algorithms of quantumbehaved particle swarm were tested with benchmark functions. The experiments show that the convergence speed of adaptive quantumbehaved particle swarm algorithm is significantly superior to quantumbehaved particle swarm algorithm. References | Related Articles | Metrics

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Remote Sensing Image Denoising by àtrous Wavelet and Nonsubsampled Directional Filter Bank XU Hua-Nan, LIU Zhe, LIU Can 2012, 46 (02):  233-238.  Abstract ( 3725 )   Save This paper proposed a method of denoising the remote sensing image based on àtrousnonsubsampled contourlet transform. The method uses the àtrous wavelet—an undecimated discrete wavelet transform algorithm to decompose the image into two parts possessing approximate part and detail parts, which are the same size as the original image. Then the nonsubsampled directional filter bank is employed to decompose the detail parts into directional subbands. The different kinds of noises of the remote sensing image can be decomposed into the wavelet coefficients in different scale and directions, with which the best method can be chosen based on the characteristics of the different noises. It is more scientific and more effective than just using one method for all kinds of noises in the past. It is proved that the method proposed in the paper is more useful in removing the noise of the image, reserving richer fine textures and edge information than other traditional filtering methods. References | Related Articles | Metrics

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Immune Evolutionary Algorithm Reusing Excellent Genes of Antibody YANG Guan-Ci-1, 2 , MA Xin-1, LI Shao-Bo-1, 2 , ZHONG Yong-2, YU Li-Ya-1 2012, 46 (02):  239-244.  Abstract ( 2801 )   Save By expounding the ideological origin of improving the clonal selection algorithm through the analysis of the specific phenomenon, the method to extract excellent gene schema to fill a memory pool from antibody set, to package excellent gene segment, and to replace low affinity antibody with high affinity antibody with probability from mutation antibody population during updating memory antibody population was designed based on clonal selection principle and algorithm, and then an improved clonal selection algorithm reusing excellent gene segment was put forward. Refering to the framework of strength Pareto evolutionary algorithm, the immune evolutionary algorithm reusing excellent genes of antibody (RGIEM) was proposed, which implements the genetic operation such as selection, crossover and recombinant by applying the improved clonal selection algorithm. Taking a series of multiobjective 0/1 knapsack problems to check RGIEA’s performance, the results show that RGIEA is capable of maintaining the diversity of population and obtaining solutions approximating to Pareto front. References | Related Articles | Metrics

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Research of Unsupervised Change Detection Method Based on the Clustering Characteristic of 3D Histogram SUN Wen-Bang-1, 2 , TANG Hai-Yan-1, CHEN He-Xin-2, WU Di-1 2012, 46 (02):  245-249.  Abstract ( 3293 )   Save The algorithm of image change detection was researched, and a novel unsupervised change detection technique was proposed. First, the optimal plane threshold and the optimal plane direction are searched by using improved 1D maximal entropy principle based on the 3D histogram clustering characteristic of different image. Then the segmentation plane is established to segment the 3D histogram into changed cluster and unchanged cluster. Finally, the changed pixels and unchanged pixels in different image are identified according to the segmentation of 3D histogram. The theoretical analysis and experiment results confirm the effectiveness of the proposed method. References | Related Articles | Metrics

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An Ensemble Learning Algorithm for Direction Prediction FU Zhong-Liang 2012, 46 (02):  250-058.  Abstract ( 4054 )   Save To resolve the learning problem in which the instances are labeled by vectors, with the destination of direction error minimization between the direction represented by prediction vector and the direction represented by actual vector, an ensemble learning algorithm for direction prediction was proposed. The methods to construct multiple prediction functions and to combine them to realize the optimized prediction of instance directions were put forward. This algorithm is very general. When the different classes are labeled by the different direction vectors of axes, the proposed algorithm is degenerated to real AdaBoost algorithm for multiclass classification, guaranteeing that the training error of the combination classifier can be reduced while the number of trained classifiers increases. When the instances are labeled by the vector composed of the classification costs of all classes, the proposed algorithm is degenerated to an ensemble learning algorithm for costsensitive classification which can minimize average classification cost. The theoretical analysis and experimental results show that the proposed algorithm is reasonable and effective. References | Related Articles | Metrics

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Provably Secure Certificateless Aggregate Signature with Constant Length LU Hai-Jun, YU Xiu-Yuan, XIE Qi 2012, 46 (02):  259-263.  Abstract ( 3463 )   Save Certificateless cryptosystem can solve the key escrow of IDbased cryptosystem and the public key authentication of certificationbased cryptosystem. A formal model of certificateless aggregate signature was proposed. It also proposed a concrete certificateless aggregate signature scheme, in which the length of the signature is independent of the signers. Based on the hardness of computational DiffieHellman problem, the proposed scheme is secure against existential forgery under adaptive chosen messages and identities in random oracle mode. References | Related Articles | Metrics

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A Group Key Distribution Scheme with Verification and Revocation WEN Mi-1, LIU Xiu-Shu-2, LI Jing-1, WANG Yong-1 2012, 46 (02):  264-268.  Abstract ( 3407 )   Save A group key distribution scheme with revocation capability was proposed for wireless sensor network. By using the broadcast information and its own secrets, the legal nodes which lost some session keys can recover them through the association between different session keys, without requiring additional transmission from the group manager.The group manager can revoke the group nodes and the group header by revocation polynomial. From the security and efficiency analysis, this key distribution scheme can achevie better security without needing more communication or storage cost. References | Related Articles | Metrics

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Study on Multistage Multiobjective Network Location Problem Based on Greedy Heuristic Algorithm ZHU Wei-a, XU Ke-Lin-a, ZHOU Bing-Hai-a, XU Jin-Chao-b 2012, 46 (02):  269-275.  Abstract ( 3712 )   Save To remedy the defects for lack of consideration of the demand change and customer satisfaction in many existing location models, this paper studied the problem under demand uncertainty and established a function which can measure customer’s satisfaction. With stochastic chance constrained programming approach, the study was extended to multiperiod decision area and a dynamic multistage multiobjective location model for distribution center (DC) was proposed. The problem objective was assessed by considering not only minimizing the cost during planning period, but also maximizing the customer satisfaction. To solve the model, this paper introduced a greedy heuristic algorithm based on assignment priority with high customer satisfaction. The computation results show that the noninferior solutions include the optimal solution of conventional location model which only seeks for minimization logistics cost, this model offers a more flexible and comprehensive decision support to distribution center location problem. References | Related Articles | Metrics

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Research and Development of Digital Forensics Platforms YANG Zhong-Huang 2012, 46 (02):  276-279.  Abstract ( 3298 )   Save Number of cyber crime increases dramatically these days and there are rapid progress on computer and smartphone systems, therefore, forensic investigators have been facing the difficulty of admissibility of digital evidence. To solve this problem, this paper developed forensic techniques and tools to collect digital evidence for computer systems and Android mobile devices. Forensics were carried out on both Windows and Linux systems to ensure judicial review of the evidence on the effectiveness of digital evidence with credibility. References | Related Articles | Metrics

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Reversible Data Hiding Based on JPEG GUO Wen-Zhong-1, GUO Shao-Hong-2 2012, 46 (02):  280-284.  Abstract ( 3189 )   Save The size of digital image file will be increased or become larger along with the digital camera’s quality. So, it will spend a lot of transmission time when the digital image is transmitted. In order to speed up the transmission rate and enhance the image’s security, this paper proposed a robust reversible data hiding method based on JPEG image. According to our experiments, it will be able to reduce the image transmission time and keep good secure lever at the same time by using this technology. References | Related Articles | Metrics

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Improvement of Discrete Fourier Transform Attack WANG Jing-Jing, CHEN Ke-Fei 2012, 46 (02):  285-288.  Abstract ( 2570 )   Save The fast discrete Fourier attack on stream cipher is not suitable for practical application as it requires the pseudorandom sequence to be successive and its complexity grows with the degree of the finite field where the discrete Fourier transform is done. The Fourier attack proposed in this paper is an improvement on the fast discrete Fourier attack. It relaxes the conditions of the former and replaces solving equations in the finite field of some high degree with shifting and adding sequences. The improved Fourier attack is tested on the Bluetooth encryption algorithm E0 to validate its effectiveness. References | Related Articles | Metrics

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Intrusion Prevention System Based on Diskless Honeypot YE He-Tian, CAI Yun-Zhang 2012, 46 (02):  289-295.  Abstract ( 2787 )   Save The plan is mainly based on DRBL (Diskless Remote Boot in Linux) to establish diskless Honeypot system and integrate intrusion prevention system(IPS) superior invasion examination and defense capability. It enables the IPS system not only to examine the malicious activity also to entrap the malicious attack. When examining the malicious act, it can warn network administrator immediately and guide the malicious act to Honeypot. By the interaction with malicious act, it can record its behavior, the invasion method and channel, provide the network administrator renewal to patch the system, reduce the system loophole and promote security largely. References | Related Articles | Metrics

Engineering Mechanics

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The Effects of Caudal Fin Shape on the Propulsion Performance of Flapping Caudal Fin ZHANG Xi, SU Yu-Min, WANG Zhao-Li 2012, 46 (02):  296-300.  Abstract ( 3108 )   Save A comprehensive study was presented on the effects of the caudal fin shape on the propulsion performance of a harmonically heaving and pitching caudal fin. A biocaudal fin propulsion mechanics was designed and a series of hydrodynamic experiments for three caudal fin shapes (the whale caudal fin, the dolphin caudal fin, and the tuna caudal fin) were performed. Then numerical simulations were done. Both the experimental and computational results indicate that the tuna caudal fin produces the highest efficiency, although the mean thrust coefficient and input power coefficient of the tuna caudal fin was the smallest. The characteristics of wake were analyzed to find that not only the wake scale of the tuna caudal fin is the smallest, but also the vorticity magnitude of the tuna caudal fin is the weakest. References | Related Articles | Metrics

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The Constitutive Relationship of Elevated Temperature Creep of 40Cr Steel YANG Chui-Jin, CHEN Ju-Bing 2012, 46 (02):  301-305.  Abstract ( 3648 )   Save The creep behaviors of 40Cr steel were investigated at various temperatures and stresses. And the creep curves based on the experimental datas were plotted. It can be observed that the steady creep and the accelerating creep processes are the dominant parts of the creep curves of the 40Cr steel in the experimental conditions. Besides，the steady creep rates can be described by the NortonPower law and the creep data can be fitted by the MonkmanGrant relationship. Then, a nonlinear constitutive equation for the 40Cr steel was proposed according to the experimental data. The parameters of the equation were determined by the least square method. At last, it can be found that the proposed equation can describe the creep behaviors of the 40Cr steel quite well by comparing the theoretical results calculated by the proposed equation and the experimental data. Related Articles | Metrics