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15 March 2003, Volume 24 Issue 3 Previous Issue    Next Issue
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Approach to block decoupling for circulant and generalized circulant composite systems Li, Jian-Hua (1); Zhao, Sheng-Zhi (1); Zhao, Jun (1); Li, Yan-Ping (1) 2003, 24 (3):  205-208.  DOI: - Abstract ( 225 )   HTML   PDF (155KB) ( 869 )   An approach of block decoupling for circulant and generalized circulant composite systems was proposed. The approach provides a convenient way to simplify circulant and generalized circulant composite systems. The stability of a circulant composite system is equivalent to that of a few lower-dimensional systems. The approach is also applicable to the generalized circulant composite systems. The structure of the generalized system is similar to that of the circulant systems. References | Related Articles | Metrics

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Robust fuzzy decentralized control for nonlinear interconnected descriptor system Wang, Yan (1); Zhang, Qing-Ling (1) 2003, 24 (3):  209-212.  DOI: - Abstract ( 254 )   HTML   PDF (250KB) ( 714 )   The robust control problem of nonlinear interconnected descriptor systems was discussed using T-S fuzzy descriptor model. A fuzzy state model for nonlinear interconnected descriptor system was presented by fuzzy modeling approach. A fuzzy decentralized controller design method was given on the assumption that the system was solvable. The robust stability of the closed-loop system with modeling errors was analyzed. On the basis of LMI, a sufficient condition was obtained. By using the property of weight value and fuzzy rules, less conservative LMI design approach was employed to establish fuzzy decentralized feedback controller. The design procedures and the effectiveness of the designed controller were illustrated by simulation. References | Related Articles | Metrics

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Channel assignment problem in cellular networks using genetic algorithms Li, Man-Lin (1); Wang, Yu-Na (1); Du, Lei (1); Wang, Guang-Xing (1) 2003, 24 (3):  213-216.  DOI: - Abstract ( 249 )   HTML   PDF (106KB) ( 811 )   In order to use the frequencies more efficiently, a new channel assignment approach based on genetic algorithms was proposed. Three constraints were considered for the channel assignment: the co-channel constraint, the adjacent constraint and the co-site constraint. The objective is to obtain a channel assignment scheme. The scheme satisfies both the traffic demand requirements and electromagnetic compatibility constraints with the lower-bound channel number. The minimum-separation encoding scheme was put forward. The traffic demand can be fulfilled throughout the iterative process using the genetic-fix operators (crossover and mutation). Some GAs operators were proposed and tested. Some well-known benchmark problems were simulated. The proposed algorithm is a better approach for solving the channel assignment problem. References | Related Articles | Metrics

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Routing mechanism in IP/DWDM optical internet Wang, Xing-Wei (1); Lin, Si-Ming (1); Di, Kui (1); Zheng, Lu-Di (2) 2003, 24 (3):  217-220.  DOI: - Abstract ( 251 )   HTML   PDF (162KB) ( 784 )   A RCSPF (Resource-Constrained Shortest Path First) routing mechanism was introduced. It can be used to extend GMPLS control plane in IP/DWDM optical Internet. By adding those necessary networks-resource constraints to those OSPF-based routing algorithms, the mechanism can decrease network congestion probability to a certain extent. The extension of source routing mechanism and the introduction of advanced distribution of network resources give support to signaling system of GMPLS framework. In order to solve the problem involved in channel allocation failure due to insufficiency of resource, a concept of relative routing and its usage approach were proposed to provide higher connection rate as well as higher bandwidth utilization in IP/DWDM optical Internet. RCSPF can provide support for deployment of IP/DWDM optical Internet. References | Related Articles | Metrics

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Nonlinear robust control based on adaptive backstepping design for STATCOM Li, Wen-Lei (1); Jing, Yuan-Wei (1); Liu, Xiao-Ping (1); Wang, Bing (2) 2003, 24 (3):  221-224.  DOI: - Abstract ( 288 )   HTML   PDF (254KB) ( 831 )   For a single-machine infinite-bus system with STATCOM affected by internal and external disturbances, the storage functions of this system were constructed based on adaptive backstepping method. A nonlinear L2 gain disturbance attenuation controller and a parameter update law were obtained. The controller can attenuate the influences of external disturbances on system output, and has strong robustness for system parameters variety because the damping coefficient is considered in internal parameter uncertainty. The design procedure based on the adaptive backstepping method is systematic and concise. References | Related Articles | Metrics

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Research on intrusion detection system for network database based on data mining Wang, Li-Na (1); Dong, Xiao-Mei (1); Guo, Xiao-Chun (1); Yu, Ge (1) 2003, 24 (3):  225-228.  DOI: - Abstract ( 315 )   HTML   PDF (191KB) ( 1513 )   An intrusion detection system model was proposed for network database NDBIDS based on data mining. The framework of the intrusion detection system and the function of components were discussed. The users' normal historical data were mined by the Apriori association-rule algorithm. The anomaly-detection model was implemented by merging and updating the rules. Three kinds of attacks, masquerading, penetration and intrusion attempt, can be detected by NDBIDS. The corresponding detection rate, false alarm rate, missing report rate and correctness rate were computed. The construction of system does not depend on experiences, so it has good flexibility. References | Related Articles | Metrics

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Improved KNN algorithm applied term feature combination technology for Chinese textual classification Zhang, Xiao-Hui (1); Li, Ying (1); Wang, Hua-Yong (1); Zhao, Hong (1) 2003, 24 (3):  229-232.  DOI: - Abstract ( 223 )   HTML   PDF (280KB) ( 1987 )   A feature combination method was presented to improve the KNN algorithm. Each term's CHI value was calculated. Multiple discriminating words with same contribution on classification were combined into one pattern. The pattern was used as the basic feature dimension. The algorithm increases the discriminating words' contribution, enhances the effect of the related terms, and decreases the dimensions of the text vector. Compared with the traditional algorithm the algorithm increases recall and precision rate greatly. References | Related Articles | Metrics

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Algorithmic design of testing with computer whether the multiplication table of binary operation forms group table Zhang, Da-Kun (1); Wang, Guang-Xing (1) 2003, 24 (3):  233-236.  DOI: - Abstract ( 281 )   HTML   PDF (179KB) ( 1016 )   An computer algorithm was developed to examine whether the multiplication table of binary operation forms the group table. Three algorithms of searching for all elements in group G row by row, searching for same elements and counting dissimilar elements line by line and row by row, were raised in testing the first sufficient necessary condition of the group table formed by multiplication table. Three algorithms, extrapolation method, small segment precedence method and natural ascending order, were given to search for elements in the same line and row of rectangle with unit 1 in testing the second sufficient necessary condition; four algorithms, single rectangle moving, simultaneous moving of (n-1) rectangle line by line (column), simultaneous moving of (n-1)2 rectangles and the moving of improved single rectangle, were raised to distinguish the 4th vertex element characteristic of the rectangle by ransacking the entire two-dimensional multiplication table; The complexity of main algorithms was discussed. The algorithm was programmed with Visual C+ +6.0. Several multiplication tables were tested by the designed software. References | Related Articles | Metrics

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Generalized M-set of complex mapping with negative power Deng, Xue-Gong (1); Song, Chun-Lin (2); Li, Zhi-Yong (2); Zhu, Wei-Yong (2) 2003, 24 (3):  237-240.  DOI: - Abstract ( 223 )   HTML   PDF (183KB) ( 559 )   The generalized Mandelbrot-sets of complex mapping f(z,c)=z-2+c were defined and created by using a new method of periodic classification. The image of generalized Mandelbrot set of z-2+c was presented, and the period-buds were colored by different RGB. Compared with current methods (escape-time arithmetic and Lyapunov method), a more practicable exact arithmetic was given. The classification of periodic-buds was given. This classification gives a better understanding of the different topological structure of the buds with the same period. This classification presents a new method to distinguish the Julia sets by the position of the parameter. An formula of the exact number of period-buds was given and the Fibomacci sequence in the Mandelbrot set of complex mapping f(z,c)=z-2+c was found, Fibomacci sequence existed in any generalized Mandelbrot set of rational mapping. References | Related Articles | Metrics

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Modelling for finished product forecasting in iron-steel enterprise Liu, Shi-Xin (1); Song, Jian-Hai (2); Tang, Jia-Fu (1); Wang, Meng-Gang (1) 2003, 24 (3):  241-243.  DOI: - Abstract ( 274 )   HTML   PDF (123KB) ( 902 )   Based on the order tracking strategy and the implementing approaches in the Integrated Production/Distribution System in an iron-steel enterprise, the product output rule in cool-rolling product line was explored using the SEMMA process of SAS/Enterprise Miner software. An artificial neural-network model for forecasting product output was built. In this forecasting model, release date and time of order at the last several processes in product line were taken as inputs, and finish date of order was taken as output. A synthetic computation experiment with neural network function of SAS/Enterprise Miner shows that the neural network models are effective approaches for forecasting product output and the precision is up to 91%. The experiment also shows that the activation function type of hidden nodes has definite effect on performance, but the number of nodes in hidden layer has little effect on performance, and data noise has some effect on performance. References | Related Articles | Metrics

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Nonlinear dynamic properties of rolling bearing-rotor-stator box with local rubbing. Yuan, Hui-Qun (1); Wen, Bang-Chun (2); Wang, De-You (3); Liu, Shu-Lun (4) 2003, 24 (3):  244-247.  DOI: - Abstract ( 266 )   HTML   PDF (220KB) ( 926 )   Based on the test apparatus of some aeroengine, nonlinear dynamic properties, especially the bifurcation and chaos behaviors, of rolling bearing-rotor-stator box with local rubbing were studied by means of numerical simulation. Different from other models, the rotor of some aeronautic engine test apparatus was supported on stator box by the rolling bearing. It was simplified as a model with three masses and six degree of freedom for studying the rubbing response of rolling bearing-rotor-stator box. In view of the case of multi-parameters, the bifurcation behaviors and chaos motion of rolling bearing-rotor-stator box were analyzed in detail. The effect of parameters such as masses ratio, impact-rub stiffness ratio, eccentric mass and bearing clearance etc, on the nonlinear dynamic properties was discussed. Abundant dynamic behaviors of rotor were revealed by the diagrams such as Poincare mapping, bifurcation diagram, phase plane plots, locus trajectory and amplitude spectrum. The stiffness ratio of impact-rub stiffness and rotor bending stiffness have distinct effect on the chaos motion properties of rotor-stator box. The responses of rolling bear-rotor-stator system are mainly periodic effect on the chaos motion properties of rotor-stator box. The responses of rolling bearing-rotor-stator system are mainly periodic motions and pseudo-period motions when stiffness ratio of impact-rub stiffness and rotor bending stiffness ratio are in some range. The response shows obvious chaos motion when the stiffness ratio is in brand range. The area of chaos gradually increase with increase of the stiffness ratio. References | Related Articles | Metrics

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Intelligent monitoring for grinding wheel passivation based on multisensor fusion Gong, Ya-Dong (1); Lu, Yang (1); Wang, Wan-Shan (1); Zhu, Xiao-Feng (2) 2003, 24 (3):  248-251.  DOI: - Abstract ( 305 )   HTML   PDF (228KB) ( 781 )   The multi-sensor fusion system was established to monitor the passivation status of grinding wheel. BP neural network was used to interfuse reasonably the acoustic emission signal, grinding force signal and power sensor signal. The output eigenvalue of the neural network was considered as a criterion to distinguish the passivation status of grinding wheel. A selfadaptive learning strategy was brought forward. A grinding-wheel passivation experiment was done. The multi-sensor fusion method can get higher recognition rate and better monitoring effect than a single sensor. In this way, an intelligent monitor can be realized and the grinding wheel can be dressed in time. References | Related Articles | Metrics

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Research on rough set-neural network fault diagnosis method Hao, Li-Na (1); Wang, Wei (1); Wu, Guang-Yu (2); Wang, Wan-Shan (1) 2003, 24 (3):  252-255.  DOI: - Abstract ( 239 )   HTML   PDF (248KB) ( 942 )   The rough set theory was used to study training sample quality, define relative concept and establish fault feature-extraction algorithm for Artificial Neural Network fault-diagnosis model. An intelligent rough-set neural-network hybrid system model was brought forward. The realization steps of the model were analyzed. The validity of these methods was tested by practical examples. Simulation was done using SAS software. The method can solve ANN architecture, sample size, and sample quality, decrease the computation time, and increase the diagnosis correctness. References | Related Articles | Metrics

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Temperature control of microwave catalysis continuous reaction experiment system Liu, Hong-Yi (1); Ma, Xian-Gang (1); Zhu, Shu-Sen (2) 2003, 24 (3):  256-259.  DOI: - Abstract ( 213 )   HTML   PDF (163KB) ( 570 )   A new type of fuzzy control was applied to control intelligently the temperature of microwave catalysis reaction in the continuous pharmacy. The fuzzy control system has a two dimensional single variable input, increment output and multi groups of self-adjustment genes. To improve the operation rate, the fuzzy control table founded in the design process was looked up in running. Multi groups of genes were used. The control dead-zones were reduced. The control precision was improved. An industry computer was used as a controller. The control algorithm was carried out in an industrial control computer. The control cycle period and the two group genes were adjusted in an experiment. The range of steady-state error is only ±1°C. The control precision and the stability of this system are suitable to the temperature control of the microwave catalysis reaction. References | Related Articles | Metrics

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3D space interpolations for magnetic abrasive finishing by virtual axis machine tool Sun, Yi-Peng (1); Meng, Xing-Zhi (1); Shi, Jia-Shun (1); Cai, Guang-Qi (1) 2003, 24 (3):  260-263.  DOI: - Abstract ( 201 )   HTML   PDF (177KB) ( 631 )   Based on the structure of the double-oscillation-axis-cutting-tool of the 3-legged 5-DOF virtual axis machine tool in parallel, the interpolation mathematic model was set up. Space-line interpolations and circular arc interpolation of the tool-path for magnetic abrasive finishing were researched. The interpolations formulae was derived. A new method was presented to classify the circular arcs. For different kinds of circular arcs, different auxiliary coordinate systems were set up. The circular arcs interpolations in the original coordinate system were transformed into the arcs interpolation in the auxiliary coordinate systems. The circular arcs quadrant transitions were solved by the application of different coordinate systems, positive stepper and negative stepper. The different circular arcs interpolations were solved. The virtual axis machine tool can be used in magnetic abrasive finishing for finishing the free form surface mould. References | Related Articles | Metrics

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Velocity and acceleration analysis of a new 3-legged in-parallel machine tool Meng, Xiang-Zhi (1); Sun, Yi-Peng (1); Huang, Wei (1); Cai, Guang-Qi (1) 2003, 24 (3):  264-267.  DOI: - Abstract ( 202 )   HTML   PDF (1586KB) ( 617 )   A new 3-legged parallel root machine tool was designed. This machine tool can machine vertically as well as horizontally when the mill head is rotated some angle. The structure and characteristic of the machine tool were introduced. The kinematics of the machine tool was studied. The kinematics equations of Corresponding position, velocity, and acceleration were deduced by analyzing the parallel stopper mechanism. Formula of the Jacobian matrix was obtained. The kinematic equations of this machine tool are very simple and easy to solve. The real-time control of the machine tool is easy. This machine tool can be applied to the wood, soft metal or nonmetal machining. References | Related Articles | Metrics

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Microstructure and mechanical properties of high strength finishing rolling rebars Bai, Yu-Guang (1); Liu, Chun-Ming (1); Ren, Hai-Peng (1); Zhang, Xiao-Gang (1) 2003, 24 (3):  268-271.  DOI: - Abstract ( 355 )   HTML   PDF (267KB) ( 2069 )   The microstructure and mechanical properties of oversea and domestic high strength finishing rolling rebar were studied. The results show that overall properties of oversea finishing rolling rebar are better than those of the domestic ones produced by the tempcore process. The oversea finishing rolling rebar show high strength, good toughness, fine grains and deep hardened layer. Through modification of alloy composition, the overall properties of finishing rolling rebar produced by Anshan Iron and Steel Company were remarkably improved, and have reached or exceeded the highest level of those of the oversea products. The remarkably improved properties were suggested coming from the grain refining and precipitation strengthening. References | Related Articles | Metrics

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Synthesis of titanium carbonitride nanopowders Li, Xi-Kun (1); Xiu, Zhi-Meng (1); Sun, Xue-Dong (1); Zheng, Long-Xi (2) 2003, 24 (3):  272-275.  DOI: - Abstract ( 295 )   HTML   PDF (142KB) ( 1107 )   Carbothermal synthesis of titanium carbonitride Ti(C1-xNx)/nanopowders from titanium hydride powder and starch under nitrogen environment was studied. The synthesis was carried out in a graphite furnace at different temperatures for different holding time in an atmosphere of flowing nitrogen. The results indicate that nitrogen content x in the titanium carbonitride Ti(C1-xNx) powder decreases with increasing reaction temperature and time and decreasing nitrogen partial pressure within a certain range used in the experiment. It is possible to control the nitrogen content in the titanium carbonitride powders by optimizing the processing parameters. A nanocrystalline of titanium carbonitride Ti(C0.5N0.5) powder with particle diameters in the range of 40-80 nm has been produced at 1750°C for 2 hours in flow nitrogen of 5 L/min. References | Related Articles | Metrics

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Numerical simulation of furnace-flow properties effected by fuel injection in high temperature air combustion furnace Wang, Li-Jun (1); Cai, Jiu-Ju (1); Zou, Zong-Shu (1); Hao, Yu-Ling (1) 2003, 24 (3):  276-279.  DOI: - Abstract ( 230 )   HTML   PDF (281KB) ( 880 )   three-dimensional velocity distribution of isothermal flow field in high temperature air combustion furnace was numerically simulated under different fuel injection conditions. The corresponding 3D-isothermal flow field was predicted by varying the distance between the fuel burner, the nozzle number of the air regenerating burners, the fuel injecting direction and fuel burner distribution around circle direction on the top surface of the furnace. The simulation results can be used to expose the optimum distance between the fuel gas nozzle and air nozzle, the optimum velocity distribution profiles by reversed injection and multi-burners symmetrically distributions, and the lower oxygen distribution so that to effectively settle the know-how technology of high temperature air combustion (HiTAC). The similar tests prove that simulation results are consistent with the experiment data well. References | Related Articles | Metrics

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Effect of unit width rolling force on hot rolling strip profile Xu, Jian-Zhong (1); Gong, Dian-Yao (1); Liu, Xiang-Hua (1); Ba, Li-Ying (2) 2003, 24 (3):  280-283.  DOI: - Abstract ( 265 )   HTML   PDF (189KB) ( 851 )   In order to build the high accuracy mathematic model of hot roll strip profile, the influence ratio calculation software is developed with influence coefficients method, based on the theory of strip profile's calculation. The ground value of special rolling force influencing ratio were calculated. The hexad polynomial fitting coefficients of special rolling force influencing ratio revised coefficients (revised by work roll diameter and back-up roll diameter) were computed. The universal calculation model of special rolling force influencing ratio was built. The influence of special rolling force and hot roll diameters on hot roll strip profile were analyzed systematically. It is shown that along with the increasing of strip width, the changing curves of special rolling force influence ratio in 4-high mill change as a parabola, the effects of work roll diameter and back-up roll diameter on special rolling force influencing ratio play an important role. The simulation can be applied to the strip profile control and the optimization of model coefficients. References | Related Articles | Metrics

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Influence of roll elastic deformation to gap setting for plate mill Hu, Xian-Lei (1); Wang, Zhao-Dong (1); Liu, Xiang-Hua (1); Wang, Guo-Dong (1) 2003, 24 (3):  284-287.  DOI: - Abstract ( 503 )   HTML   PDF (311KB) ( 1412 )   Base on the mechanical model of plate rolling process, the gap variation was transferred to roll elastic deformation. By the influence function method the influence of plate width, work roll radius, backup roll radius, work roll crown, backup roll radius and rolling force on gap setting were calculated. Results show that: 1. roll deformation decreases linearly with the increase backup roll radius; 2. roll deformation is increasing linearly with the increases of work roll radius; 3. roll deformation increases linearly with the increase of backup roll crown; 4. roll deformation is linear to work roll crown, but the plate width can change the direction of linear relation; 5. roll deformation increase linearly with the increase of rolling force. If the rolling force is constant, the roll deformation is invariant. References | Related Articles | Metrics

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Numerical simulation of hydrofracturing in anisotropic pore pressure fields Leng, Xue-Feng (1); Tang, Chun-An (1); Li, Lian-Chong (1); Yang, Tian-Hong (1) 2003, 24 (3):  288-291.  DOI: - Abstract ( 294 )   HTML   PDF (209KB) ( 1130 )   By using numerically testing method, hydrofracturing in anisotropic pore pressure fields was studied. The simulated results indicate that the macroscopic failure evolution process was induced by microscopic fracture under pore pressure, which agreed well with the experimental results. It is found that the fracture is influenced by both pore pressure magnitudes on a local scale around the crack tip and by the orientation and distribution of pore pressure gradients on a global scale. The fractures always propagate towards the regions of higher local pore pressure and fracture pressure decreases with the increasing of local pore pressure. The research may be applied to control the hydraulic fracture orientation in the field. References | Related Articles | Metrics

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Experiments on the mechanical effects of sandstone with chemical erosion under the triaxial compress Chen, Si-Li (1); Feng, Xia-Ting (1); Zhou, Hui (2) 2003, 24 (3):  292-295.  DOI: - Abstract ( 256 )   HTML   PDF (230KB) ( 1078 )   Damage processes of sandstone with chemical erosion under the triaxial load were tested using CT technology. The influence of the solutions with different pH values and different components was investigated. Meanwhile stress-strain curve of sandstone was also obtained. The experimental results show that the influences of different environments on mechanical properties of sandstone are different, the greater the acidity of solution the greater the erosion to sandstone, and so the chemical erosion is one of most important influence to rock mechanical properties. The results can be used as a reference to analyze the meso-mechanics of rock damage evolution, to set up the corresponding damage constitutive model, and to offer an effective parameter for exactly estimating the safety and stability of many rock engineering such as dam foundation, slope and tunnel which are related to water. References | Related Articles | Metrics

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- - 2003, 24 (3):  296-299.  DOI: - Abstract ( 219 )   HTML   PDF (183KB) ( 897 )   - References | Related Articles | Metrics

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- - 2003, 24 (3):  300-302.  DOI: - Abstract ( 218 )   HTML   PDF (126KB) ( 661 )   - References | Related Articles | Metrics

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- - 2003, 24 (3):  303-305.  DOI: - Abstract ( 205 )   HTML   PDF (172KB) ( 980 )   - References | Related Articles | Metrics