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15 May 2003, Volume 24 Issue 5 Previous Issue    Next Issue
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Establishment of parameters of genetic algorithm based on uniform design He, Da-Kuo (1); Wang, Fu-Li (1); Zhang, Chun-Mei (2) 2003, 24 (5):  409-411.  DOI: - Abstract ( 497 )   HTML   PDF (148KB) ( 2292 )   By analysing the function and significance of the operational parameters of a genetic algorithm, the establishment of the parameters of a genetic algorithm can be described as an optimization problem of multifactor and multilevel. In order to gain the optimal performance of seeking an optimal solution of a genetic algorithm, and taking the feasibility of the parameters establishment into account, an uniform design method, which is used to solve the multi-factor and multi-level optimization problems, was proposed to establish operational parameters of a genetic algorithm. References | Related Articles | Metrics

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Sufficient condition on the stability of descriptor interval systems Zhang, Da-Qing (1); He, Xi-Qin (2); Zhang, Qing-Ling (1) 2003, 24 (5):  412-415.  DOI: - Abstract ( 227 )   HTML   PDF (169KB) ( 603 )   The stability for linear continuous-time descriptor systems with an interval matrix was studied. Using Gershgorin's theorem, a sufficient condition was derived to judge a descriptor interval system to be regular, impulse-free and stable with the constraint that all the main-diagonal values of the system matrix A arc negative. Nevertheless, the sufficient condition was further developed to fit the case that the radius of the Gershgorin disc is comparatively large. Two examples were used to illustrate the validity of the method. And a necessary and sufficient condition is suggested to determine an interval matrix to be nonsingular. References | Related Articles | Metrics

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Optimal control for large-scale descriptor systems with symmetric circulant structure Yao, Bo (1); Zhang, Qing-Ling (1) 2003, 24 (5):  416-419.  DOI: - Abstract ( 168 )   HTML   PDF (166KB) ( 654 )   The optimal control for large-scale descriptor systems with symmetric circulant structure were studied. Considering that many control problems are related to the solving of the algebraic Riccati equation and Lyapunov matrix equation, a method of solving the equations is suggested for large-scale systems with symmetric circulant structure. Exploiting the special structure of symmetric circulant systems, the problem of solving these systems can be simplified to the one of solving lower dimension systems. The quadratic optimal control problem was investigated for large-scale descriptor systems with symmetric circulant structure by using the simplified solution of Riccati equation. References | Related Articles | Metrics

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Cross-coupling speed controller Cao, Yang (1); Xu, Xin-He (1) 2003, 24 (5):  420-423.  DOI: - Abstract ( 369 )   HTML   PDF (1036KB) ( 619 )   Based on the study of robot subsystem of soccer-robot, a kind of compositive error model was set up by the analysis of wheeled-robot trajectory-tracking error. The design principles, arithmetic and implemental methods of cross-coupling tracking error compensator were presented based on fuzzy reasoning. By adding additional compensation on the input of speed loop of each wheel, the compensator can improve the trajectory tracking accuracy without changing the configuration of the robot inner-speed loop. The simulation was based on the mathematic model of soccer robot. The method can improve the trajectory tracking accuracy of wheeled robot effectively. References | Related Articles | Metrics

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New scheme of improving link key for Bluetooth security Ren, Xiu-Li (1); Quan, Chengbin (1); Fan, Li-Jun (1); Luan, Gui-Xing (2) 2003, 24 (5):  424-428.  DOI: - Abstract ( 396 )   HTML   PDF (193KB) ( 451 )   Bluetooth has two defects in its security. When the encryption key is exchanged between two units, the third party can capture the encryption key as one of the two units to communicate with the other. The third party can obtain the public Bluetooth address, easily trace all operation of the unit and know the other. A new scheme was proposed to improve a link key. By making use of DES algorithm, a link key was created by constructing a Hash function to ensure both information security and establish a more robust security mechanism for the Bluetooth wireless ad-hoc network. The scheme can be regarded as a reference of revising the unit key. References | Related Articles | Metrics

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Security mechanism of a web service-based enabling platform Dong, Xiao-Mei (1); Wang, Li-Na (1); Yu, Ge (1); Shen, De-Rong (1) 2003, 24 (5):  437-440.  DOI: - Abstract ( 257 )   HTML   PDF (198KB) ( 413 )   An enabling service platform based on web services was introduced. This platform was designed for medium-small scale enterprises allying dynamically for their business processing. The security threats to it were analyzed. A set of security mechanism suited for the platform was proposed. According to the mechanism, the function such as information security, access control, digital signature, authentication and intrusion detection were provided. In the mechanism, AES and chaos-based stream cipher algorithms were applied for data encryption. RSA algorithm was applied for both digital signature and key exchange. Guillou-Quisquater protocol was applied for authentication and a RSA-based secrete-sharing scheme was proposed for key storage. Neural network, data mining and computer immunology-based methods were incorporated in the intrusion detection system. The security of the mechanism was analyzed. References | Related Articles | Metrics

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Fuzzy control routing protocol for MANET networks Zhao, Chun-Xiao (1); Wang, Guang-Xing (1) 2003, 24 (5):  441-444.  DOI: - Abstract ( 176 )   HTML   PDF (175KB) ( 529 )   A mobile ad-hoc wireless network's character was introduced. Based on the dynamic source routing (DSR) protocol, an efficient on-demand routing protocol is presented, called the extension of the dynamic source routing (EDSR) protocol. The use of fuzzy controlling techniques was investigated. For each metric, a fuzzy membership function was defined to predict a more stable Sink. A fuzzy-inference rule base was implemented to generate the fuzzy cost of each link. The protocol selects the most stable path based on mobility prediction and establishes multiple paths for a route discovery procedure, thus conserving network bandwidth and reducing route reconstruction times when routes path failed. Compared with DSR, the protocol has high packet delivery ratio with low control overhead. References | Related Articles | Metrics

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Architecture and algorithm of web services dynamic integration Pan, Chang-Sheng (1); Yu, Hao-Hai (1); Wang, Guang-Xing (1) 2003, 24 (5):  445-448.  DOI: - Abstract ( 130 )   HTML   PDF (170KB) ( 477 )   The characters of the Web Services dynamic integration based on SOAP and WSDL were analyzed. A kind of architecture and algorithm was designed for Web Services dynamic integration platform. The platform employs the metadata, retrieved from WSDL files and stored in database, to invoke SOAP and control workflow. Compared with other Web Services integration resolutions, such as WSFL and WSIF of IBM, the platform makes the Web Services integration more flexible and convenient because the providers of the Web Services can maintain their services on-line through internet, the platform needs no work, and this process doesn't involve programming. References | Related Articles | Metrics

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Norm-based fuzzy clustering method for multi-dimension data Wang, Li-Na (1); Fei, Ru-Chun (1); Dong, Xiao-Mei (1); Yu, Ge (1) 2003, 24 (5):  449-452.  DOI: - Abstract ( 227 )   HTML   PDF (167KB) ( 762 )   The relationship between the similitude of data and the norm of a vector was discussed according to the definition of the similitude between multi-dimension data. A norm-based fuzzy clustering method for multi-dimension data was proposed. Each multi-dimension datum is regarded as a multi-dimension vector, and the data are sorted according to the vector-related norms. The approximate solution of clustering is presented. Each approximate cluster is further decomposed according to another norm by the same way. Then, the approximate solution of fuzzy clustering for multi-dimension data can be obtained. Finally, the exact clusters can be found from the approximate clusters using traditional methods. The fuzzy similarity relation does not need to be built when approximately clustering for multi-dimension data, so the total counts of accessing database is comparatively small. Hence, the method proposed is high efficient and fits to the clustering of large databases. References | Related Articles | Metrics

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Completion of synchronous codes Liu, Qun (1); Li, Hong (1) 2003, 24 (5):  453-456.  DOI: - Abstract ( 182 )   HTML   PDF (159KB) ( 589 )   By the degree of synchronous codes, some combinatorial characteristic of synchronous codes and prefix synchronous codes were studied. The completion of these codes was given. For synchronous codes, there is a word with degree 1. All words beginning and ending by this word are a free submonoid. Using the base of this free submonoid, the completion of synchronous codes was constructed. For prefix synchronous codes, an unborderd word with some special characteristic was found. The completion of a prefix synchronous code was made from the code itself. The prefix root of the words ends by this word and doesn't begin by the code words. References | Related Articles | Metrics

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Optimum algorithm for bifurcation of algebra iterated mapping Li, Yong-Qiang (1); Liu, Jie (1); Hou, Xiang-Lin (2) 2003, 24 (5):  457-459.  DOI: - Abstract ( 182 )   HTML   PDF (161KB) ( 913 )   The accurate computation for getting ramification of algebra iterated system was studied by the analysis of the double period bifurcation of Logistic dynamic mapping system with ecological characteristic. Regarding iterated processes as objective function, parameters of algebra iterated system as design variables, and boundary condition of iterated variables as constrains, a new optimum method was proposed. The method was used to calculate bifurcation algebra iterated mapping. Turning constrains into punishing items, the punishing function method was used to deal with the optimum problem, and accurate results were acquired. The method can solve ramification of algebra iterated system rapidly and exactly. References | Related Articles | Metrics

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Effect of pipeline on stability of electro-hydraulic proportional position control system Zhou, En-Tao (1); Zhou, Shi-Chang (1); Liao, Sheng-Hang (1) 2003, 24 (5):  460-463.  DOI: - Abstract ( 222 )   HTML   PDF (262KB) ( 804 )   A system to control uasymmetrical cylinder position by a proportional valve was studied. The mathematical model of the electro hydraulic proportional-position control system with pipeline was built. Two models of the control system, with and without pipeline, were investigated by computer simulation. The effect of pipeline has an effect on the stability of electro-hydraulic proportional-position control system. The length and diameter of the pipeline and the flow-pressure coefficient can obviously inflect the stability of the system. References | Related Articles | Metrics

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Application of virtual reality on concrete pump car design Zhou, Shu-Wen (1); Zhang, Guo-Zhong (1); Zhang, Si-Qi (2) 2003, 24 (5):  464-466.  DOI: - Abstract ( 241 )   HTML   PDF (179KB) ( 669 )   Virtual Reality, robot technology and intelligent optimization method were applied to simulate the working process of a concrete pump car. Data reading from three-dimensional model, virtual environment creation and intelligent search with genetic algorithm were studied. The concrete pump car was modeled in 3DMAX, then it was imported into the virtual scene. The model can simulate the process of concrete pouring, through which search algorithm can be tested. A virtual reality system was developed with Visual C++ 6.0. The interface is friendly and authentic. The simulation suggests a new way to develop a concrete pump cars. References | Related Articles | Metrics

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Discontinuous precipitation of spinodal Al-Zn alloy with symmetrical composition Wang, Da-Peng (1); Hao, Shi-Ming (1); Dong, Dan-Yang (1); Zhao, Gang (1) 2003, 24 (5):  467-470.  DOI: - Abstract ( 156 )   HTML   PDF (308KB) ( 799 )   Through microstructure observation and X-ray diffraction analysis, characteristic of transformation mechanics of discontinuous precipitation in Al-Zn alloy with symmetrical composition under 277°C were investigated after attaining its single phase microstructure by solution treatment. It is found that spinodal decomposition and subsequent continuous coarsening occur during the incubation period. The discontinuous precipitation shows lamellar microstructure composed of Al-based solid solution (a) with f. c. c. structure and Zn-based solid solution (β) with h. c. p. structure. The nucleation site depends on the transformation temperature and the cardinal nucleation sites take place along the grain boundaries. The transformation dynamics follows the relationship of Avrami Equation, whose exponent is 2. References | Related Articles | Metrics

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Modeling the earing behavior of polycrystalline aluminum alloy in cup drawing Hu, Zhuo-Chao (1); Zhang, De-Fen (1); Zuo, Liang (1); Wang, Fu (1) 2003, 24 (5):  471-474.  DOI: - Abstract ( 393 )   HTML   PDF (253KB) ( 903 )   A new method is proposed to predict the earing behavior of polycrystallme Aluminum sheet. The method is based on the Tucker's theory of earing proposed for single crystals by consideration of the partition of the orientation space. The number, position and relative heights of earing tendency for some important ideal orientations in single crystal aluminum was calculated. The calculated result is the same with the result from Tucker's theory. The new method was used to predict the earing behavior of the material with no texture, cold rolled sample, recrystallization sample arid the finish product from South-Western Aluminum plant. It is shown that the predictions are in good agreement with experimental results. The texture can be regulated and adjusted according to the earing behavior of polycrystalline aluminum alloy sheet predicted by the method. This is also very useful in the fast prediction system of texture-property on production line. References | Related Articles | Metrics

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Eliminating aniline in water by sodium permanganate oxidation Ren, Guang-Jun (1); Zhai, Yu-Chun (1); Tian, Yan-Wen (1); Zhang, Bo-Song (2) 2003, 24 (5):  475-477.  DOI: - Abstract ( 205 )   HTML   PDF (128KB) ( 620 )   Eliminating aniline in water was investigated by sodium permanganate. It is showed that with the increase of sodium permanganate, aniline eliminating rate increases. Aniline eliminating rate reaches 92.12% by the condition of aniline concentration lO mg/L, temperature 18°C ,pH 6.8, reaction time 30 min and sodium permanganate 30 mg/L. The pH value of water sample plays a role on aniline elimination. The effect of removing aniline in alid or alkaline solutions is more significant than in neutral water. The aniline eliminating rate is 97.55% at pH value 3 and 96.33% at pH value 11. Increasing the temperature or the reaction time has good effects on removing aniline. By the cooperation of permanganate and the formed oxygen, aniline is oxidated into guinone and removed. References | Related Articles | Metrics

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Dynamic recrystallization of a 22CrS gear steel Wang, Bing-Xin (1); Liu, Xiang-Hua (1); Wang, Guo-Dong (1) 2003, 24 (5):  478-481.  DOI: - Abstract ( 205 )   HTML   PDF (305KB) ( 935 )   The dynamic recrystallization and austenite grain size after recrystallization in a new Mn-Cr gear steel were studied at a strain up to 0.7, at a range of temperature from 850 to 1 150°C , at strain rate from 0.1 to 1 s-1 and at initial austenite grain size from 70 to 150 μm using a Gleeble 1500 thermomechanical test system. The experimental results show that strain rate, deformation temperature and initial austenite grain size are three factors with strong effects on the dynamic recrystallization. Dynamic recrystallization takes place if deformation condition Z is less than the critical value of Zc. The mean dynamically recrystallized grain size (D) is determined only by deformation condition Z and does not depend on the initial austenite grain size. D decreases with increase of Z. The equation of Z=AD-3.91 was derived to show the relationship between D and Z. References | Related Articles | Metrics

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Influences of an alternate magnetic field on the liquidus and solidus temperatures of 7075 Al alloy Ban, Chun-Yan (1); Ba, Qi-Xian (1); Zhu, Li-Ying (1); Cui, Jian-Zhong (1) 2003, 24 (5):  482-484.  DOI: - Abstract ( 285 )   HTML   PDF (154KB) ( 1061 )   Solidification of 7075 Al alloy was investigated in an alternate magnetic field with frequency being 50 Hz and density being 0.06 T, 0.09 T and 0.12 T, respectively. The Resistance-Temperature curves of the solidifications were measured with the method of double bridges to examine the liquidus and solidus temperatures of the alloy under different conditions. It is found through the experiments that, when the alloy is solidified in an alternate magnetic field, its liquidus and solidus temperatures increase obviously and the solidification interval diminishes. The stronger the magnetic density is, the more evident the effects are. Compared with the alloy solidified without a magnetic field, the liquidus temperature increases 7.5-12.5°C and the solidus temperature increases 10-20 °C by the alternate magnetic filed. It is suggested that the barrier potential required by the atom cluster jumping from liquid phase to solid phase at the front of liquid-solid interface is decreased by the alternate magnetic filed. References | Related Articles | Metrics

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Pit morphology of SiCp/2024 Al metal matrix composites He, Chun-Lin (1); Zhang, Bin (1); Shang, Li-Juan (2); Cai, Qing-Kui (3) 2003, 24 (5):  485-487.  DOI: - Abstract ( 203 )   HTML   PDF (205KB) ( 526 )   The pit morphology of SiCp/2024 Al metal matrix composites (MMCs) in 3.5% NaCl solution was investigated by scanning electron microscopy and compared with that of corresponding unreinforced matrix alloy. The results show that the pit morphology depends on the volume fraction and size of SiC particles. The pits on the MMCs are more numerous and smaller in size as the volume fraction increases or particle size is reduced. And, the pits are a little bigger, less numerous and more non-uniform in spatial distribution when compared with those on the 2024 Al. Moreover, severe local corrosion occurs on the MMCs except the one reinforced by 30% SiC volume fraction. The corrosion mechanism of the MMCs is galvanic corrosion between the phase rich in Cu and the matrix, and between the SiC particle and the matrix. References | Related Articles | Metrics

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Limited values of axial compression ratio of steel reinforced high strength concrete column Xu, Ya-Feng (1); Wang, Lian-Guang (2); Liu, Zhi-Yang (1) 2003, 24 (5):  488-490.  DOI: - Abstract ( 230 )   HTML   PDF (705KB) ( 526 )   On some assumptions, by analyzing the stress exerted on reinforced steel bar, on concrete and on section of steel reinforced high strength concrete column, the limited axial force which affects the damage form of steel reinforced high strength concrete column was examined. The limited values of axial compression ratio was calculated. The analysis of the axial compression ratio shows that the limited values of axial compression ratio vary with the size of the steel, concrete and column sections. Therefore the different limited values of axial compression ratio should be adopted in the engineering design according to specific applications. References | Related Articles | Metrics

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Theoretical analysis on the modulus of construction composite foundation Wang, Feng-Chi (1); Zhu, Fu-Sheng (1); Wang, Xiao-Chu (2) 2003, 24 (5):  491-494.  DOI: - Abstract ( 230 )   HTML   PDF (154KB) ( 695 )   Composite modulus is a key parameter of composite foundation, which is calculated in present by virtue of area ratio formula. Practically there is a big error between calculated value and measured value. Taking account of the pile length and the nature of pile-end soil, the bearing mechanics of composite foundation pile were used to correct the area ratio formula. Comparatively, the value calculated by the corrected formula is more accurate than by area ratio formula. With the increase of pile length, composite modulus increases linearly. The smaller the ratio of pile-soil modulus, the bigger the change. Similarly, with the increase of stiffness of pile-end soil, composite modulus increases. However, the bigger the ratio of pile-soil modulus, the bigger the change. So, the ratio of pile-soil modulus should be regarded as a criterion to differentiate the type of composite foundation. References | Related Articles | Metrics

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- - 2003, 24 (5):  495-498.  DOI: - Abstract ( 202 )   HTML   PDF (295KB) ( 905 )   - References | Related Articles | Metrics

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- - 2003, 24 (5):  499-502.  DOI: - Abstract ( 182 )   HTML   PDF (723KB) ( 683 )   - References | Related Articles | Metrics

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- - 2003, 24 (5):  503-506.  DOI: - Abstract ( 188 )   HTML   PDF (196KB) ( 1247 )   - References | Related Articles | Metrics

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- - 2003, 24 (5):  507-509.  DOI: - Abstract ( 174 )   HTML   PDF (131KB) ( 683 )   - References | Related Articles | Metrics