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15 August 2005, Volume 26 Issue 8 Previous Issue    Next Issue
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Reliable robust control for a class of uncertain switched nonlinear systems Wang, Rui (1); Zhao, Jun (1) 2005, 26 (8):  715-717.  DOI: - Abstract ( 223 )   HTML   PDF (226KB) ( 634 )   The reliable robust control is studied for a class of uncertain switched nonlinear systems disturbed by uncertain structural parameters. It is assumed that the nonlinear terms satisfy the norm-bounded condition and the parameter uncertainty is time-variable. Based on multiple-Lyapunov function method, the design of hybrid state feedback-reliable controllers is given such that the corresponding closed-loop system is globally asymptotically stable for all admissible uncertainties and actuator failures. The simulation result demonstrated the effectiveness of the proposed approaches. References | Related Articles | Metrics

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CMAC-based fuzzy controller for strip flatness pattern recognition Liu, Jian-Chang (1); Wang, Zhu (1) 2005, 26 (8):  718-721.  DOI: - Abstract ( 225 )   HTML   PDF (262KB) ( 908 )   Based on CMAC (cerebellar model articulation controller) neural network, a pattern recognition method for strip flatness is proposed with a flatness fuzzy controller based on the recognized results designed. Thus, the pattern recognition and controller design are combined into one. The CMAC is used to recognize the membership levels in regard to six basic patterns of common defects in flatness and then, as the direct forepiece of fuzzy controller, serve for seeking these membership levels. Analyzing the characteristics of defect in flatness, the fuzzy set is defined rationally to reduce greatly the calculation of fuzzy reasoning. The simulation result showed that the pattern recognition method of flatness offers high recognizing precision with which the designed fuzzy controller for flatness can control a defect to an expected extent with satisfactory controllability. References | Related Articles | Metrics

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Control strategy of biped robot and open/closed-loop iterative learning control Wang, Bin-Rui (1); Xie, Hua-Long (1); Cong, De-Hong (1); Xu, Xin-He (1) 2005, 26 (8):  722-725.  DOI: - Abstract ( 313 )   HTML   PDF (310KB) ( 950 )   The master-slaver dual-leg coordination control was used for biped robot with heterogeneous legs (BRHL) to simplify its planning scheme, of which the key of coordination is gait tracking control. Bionic knee joint enables the robot to walk more like human, but its modeling is complex and the control of bionic leg to track artificial leg is difficult. The P-type open/closed-loop iterative learning control (ILC) is therefore put forward to combine together the advantages of open-loop and closed-loop ILC without a model to rely on so as to fit the control of path tracking of complicated robot. The convergence of the algorithm proposed is proved and a simulation based on virtual prototype was done, of which the results showed that the algorithm is efficient and robust especially its converging speed is higher than individual open-loop or closed-loop ILC. References | Related Articles | Metrics

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Neural network based prediction of endpoint in ladle refining process Gao, Xian-Wen (1); Zhang, Ao-An (1); Wei, Qing-Lai (1) 2005, 26 (8):  726-728.  DOI: - Abstract ( 232 )   HTML   PDF (252KB) ( 1018 )   Predicts the endpoint in ladle refining process by way of developing a relevant model through modified BP neural network in combination with the characteristics of ladle refining process. The prediction is based on such a concept that the parameters of the model are analyzed and determined in terms of the in site data recorded previously with other existing neural network models taken as reference, then the prediction model is set up. Other related data can therefore be predicted according to the model. Simulation results showed that the endpoint predicted by applying the modified BP neural network benefits much the ladle refining process. References | Related Articles | Metrics

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Research on optimal design of logistic distribution center for b2c e-commerce Jiang, Zhong-Zhong (1); Wang, Ding-Wei (1) 2005, 26 (8):  729-732.  DOI: - Abstract ( 273 )   HTML   PDF (328KB) ( 835 )   Based on the size of logistic distribution centers and the characteristics of what the customers demand for business-to-customer (B2C) e-commerce companies, a mathematical model is developed to optimize the design of the distribution centers with a hierarchical agglomerative clustering method used to estimated the fuzzy cost of distribution transport from distribution centers to customers. The model is in fact a mixed 0-1 non-linear fuzzy programming model with NP-hard complexity. It is converted into a clearer one which is solved by a genetic algorithm developed in terms of embedded tabular operation. The effectiveness and feasibility of the model and algorithm are verified by an actual computational example, thus providing a new way for the rational design of distribution centers for B2C e-commerce companies. References | Related Articles | Metrics

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Approach based on domain knowledge to text categorization Zhu, Jing-Bo (1); Chen, Wen-Liang (1) 2005, 26 (8):  733-735.  DOI: - Abstract ( 356 )   HTML   PDF (2425KB) ( 1181 )   A knowledge-based text categorization method is proposed, taking domain features as textual features to improve text representation function and considering text categorization as aggregation computation procedure. A feature re-selection and re-weighting technique is proposed for text indexing procedure. To learn feature aggregation functions from labeled training collection automatically, a learning method based on mutual information is employed. Comparative experiment results showed that the text categorization method based on domain knowledge works better than the conventional naive Bayes classifier based on bag-of-words model as a whole and that using domain knowledge will improve effectiveness of classifying similar or antithetical topics. References | Related Articles | Metrics

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A kind of dynamic routing algorithm of weight allocation for traffic engineering Du, Li (1); Yang, Lin (1); Li, Jun (1) 2005, 26 (8):  736-738.  DOI: - Abstract ( 212 )   HTML   PDF (232KB) ( 514 )   Proposes a new dynamic routing algorithm of weight allocation for MPLS networks, taking mainly the hops, demands for bandwidth fragment and idle bandwidth rate into account to allocate rationally the bandwidth resource for incoming traffic. After implementing the routing selection at the border of MPLS networks, the explicit routing technique in MPLS is used to get rid of the effect of routing algorithms at middle nodes so as to give an LSP that will meet QoS requirements of all kinds of services. The simulation results indicated that the new algorithm can balance the traffic better, decrease the congestion in networks, utilize sufficiently the network resources by decreasing bandwidth fragment and enhancing the utilization of bandwidth and guarantee QoS to a certain extent by improving some parameters such as the losing rate. References | Related Articles | Metrics

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Situation assessment/diagnosis model based on Bayesian Networks for hydropower equipment Su, Yu (1); Zhao, Hai (1); Su, Wei-Ji (1); Xu, Ye (1) 2005, 26 (8):  739-742.  DOI: - Abstract ( 319 )   HTML   PDF (2563KB) ( 770 )   Aiming at uncertainty and the poor generality of hydropower equipment fault diagnosis, a general situation assessment model based on Bayesian Networks is put forward. The model includes three levels, i.e., character level, understanding level, and assessment level. Nodes in Bayesian networks are divided into situation and event nodes according to their functions. During reasoning the information acquired by sensors are taken as the evidence of event node to update the probability of situation node and in turn, to influence the probability of event nodes. The diagnosis model in application of hydropower speed governor system shows that the veracity can be up to 95.2%, thus indicating the reliability provided by the situation assessment model. References | Related Articles | Metrics

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Transformation of Nb-bearing microalloyed low carbon steel during continuous cooling Yi, Hai-Long (1); Du, Lin-Xiu (1); Wang, Guo-Dong (1); Liu, Xiang-Hua (1) 2005, 26 (8):  743-746.  DOI: - Abstract ( 290 )   HTML   PDF (521KB) ( 799 )   The transformation behavior of Nb-bearing microalloyed low carbon steel during continuous cooling with deformation at different temperatures was investigated by means of Gleeble-1500 thermomechanical simulator. The continuous cooling transformation (CCT) curves under deformed and undeformed conditions were obtained by way of thermal dilation and metallography. The influence of deformation parameters on microstructure was analyzed. The results showed that the transformation of pearlite is accelerated through high-temperature deformation, and transformation range of ferrite is reduced when deformed at the temperature above 950°C. In view of the starting transformation temperature, the bainite transformation is extended when deformed at 950°C. At the same deformation temperature, bainite amount decreases but proeutectoid ferrite amount increases with the increasing deformation amount. The formation of high-temperature equiaxed ferrite is accelerated and bainite transformation retarded when deformed at the temperature below 900°C. References | Related Articles | Metrics

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Developing an ultra-low carbon deep-drawing sheet steel by ferritic hot rolling process Wang, Zhao-Dong (1); Guo, Yan-Hui (1); Zhao, Zhong (1); Sun, Da-Qing (1) 2005, 26 (8):  747-750.  DOI: - Abstract ( 277 )   HTML   PDF (319KB) ( 648 )   How the processing conditions affect the properties especially the drawability of a ferritic hot-rolled and annealed Ti-IF sheet steel was investigated. With the sample workpieces lubricated during ferritic rolling and coiled at high temperature, the maximum plastic strain ratio of sample was 1.38 with elongation over 50%. For the samples rolled with lubricating interity further annealed, the strong {111} recrystallization texture presents uniform distribution in thickness direction with low of {110} recrystallization texture even in surface layer. However, under unlubricated rolling conditions, the weak {111} texture presents ununiform distribution with high intensity of {110} recrystallization texture especially in surface layer. To acquire the deep drawability, the reheating temperature, finished temperature and coiling temperature should be 1100-1150°C, 750-800°C and over 650°C, respectively. References | Related Articles | Metrics

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On-line implementation of full automatic rolling control on plate mills in tandem Jiao, Zhi-Jie (1); He, Chun-Yu (1); Niu, Wen-Yong (1); Liu, Xiang-Hua (1) 2005, 26 (8):  751-754.  DOI: - Abstract ( 217 )   HTML   PDF (322KB) ( 1003 )   How to implement the on-line full automatic rolling control on plate mills in tandem was introduced. Comparing the manual control mode with full automatic control mode in plate rolling process, the key points to implement the full automatic rolling control were summarized. Then, the control function was allocated reasonably in a two-level control system. With the coordination provided between the process control system and basic automation system, the full automatic rolling control was therefore implemented successfully in site, including the control of horizontal roller bed, of setting the number of vertical passes and of each and every rolling pass. The implementation indicates that the level of automation is further raised for plate mills. References | Related Articles | Metrics

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Optimal ITAE tuning formulae for parameters of PID controller Zhang, Fu-Bo (1); Wang, Guo-Dong (1); Zhang, Dian-Hua (1); Liu, Xiang-Hua (1) 2005, 26 (8):  755-758.  DOI: - Abstract ( 389 )   HTML   PDF (321KB) ( 888 )   For a class of controlled plants that can be approximately described as a first order model with pure time-lag, a set of optimal expressions based on the characteristic parameters of the controlled plant are proposed by way of parameter optimizing, data fitting and so forth to tune the parameters of PID controller. Testing results indicated that the PID control system designed in this way has such good characteristics as short adjusting time, small overturning and small static error especially the dynamic characteristics which are more excellent than from any other empirical Formulae. In addition, its control effect will remain unchanged even if the ratio of pure time-lag to time constant of the controlled plant is big. Being simple and easy to implement, the approach proposed will not only solve the problem that the tuning effect on conventional PID parameters is improper but also provide a sound foundation for building further a self-adaptive PID control system based on the latent process parameter. References | Related Articles | Metrics

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Experimental investigation on circulation flow in RH refining system with swirling flow Li, Bao-Kuan (1); Luan, Ye-Jun (1); Qi, Feng-Sheng (1); Huo, Hui-Fang (1) 2005, 26 (8):  759-762.  DOI: - Abstract ( 257 )   HTML   PDF (475KB) ( 586 )   Investigation on the possibility of the improving the refining efficiency by applying swirling flows in the up-leg of RH refining process, the swirling flows are produced by using the impeller with the six plane blades and axial flow impeller. Difference of gas-liquid flow phenomena between without and with the swirling flow is analyzed using the water model experiments. The ultrasonic flowmeter is used to measure the circulation flow rate. A video recorder is used to record the two-phase flow patterns. The water model experiments show that the circulation flow rate with swirling flow increases significantly. Caused by the centripetal force, the gas bubbles and the inclusions, whose densities are smaller than that of liquid, concentrated on the central zone of the up-leg. Where the collision and the coagulation of the bubbles and the inclusions can be increased remarkable. The attachment of the bubbles on the inner walls of the up-leg of RH vessel is also avoided. Thus the life of the RH vessel can be improved. References | Related Articles | Metrics

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Oxidative dephosphorization of chromium-containing hot metal by BaO-CaO based refining slag Li, Hua-Bing (1); Jiang, Zhou-Hua (1); Huang, Xiao-Ying (1); Liang, Lian-Ke (1) 2005, 26 (8):  763-765.  DOI: - Abstract ( 225 )   HTML   PDF (261KB) ( 524 )   Oxidative dephosphorization of chromium-containing hot metal with different initial carbon contents was carried out by BaO-CaO based refining slag in a MoSi2 furnace in argon atmosphere. The results showed that the best effect of dephosphorization comes out when the initial carbon content in the hot metal is in the range from 3% to 4% and the dephosphorization rate is over 60% at 1500°C. The temperature of oxidative dephosphorization has significant effect on dephosphorization rate which reduced greatly with increasing temperature. It is proper to control the temperature in the range from 1500°C to 1550°C. Chromium lass is negligible, and the increase in chromium content is found while the initial carbon content in hot metal is high. References | Related Articles | Metrics

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Fuzzy force control of constrained robot manipulators based on impedance model in unknown environment Liu, Hong-Yi (1); Wang, Lei (1); Wang, Fei (1) 2005, 26 (8):  766-769.  DOI: - Abstract ( 235 )   HTML   PDF (316KB) ( 647 )   Proposes a novel algorithm to determine the reference trajectory, which is to be applied to the traditional impedance model. A reference scaling factor is thus developed to tune the reference trajectory in order to adapt the reference trajectory generated for the changeable unknown stiffness in environment. The reference scaling factor is determined by fuzzy reasoning in accordance to the information feedback on forces in contact. Moreover, the impedance model parameters are adjusted fuzzily according to the change of forces in contact to reduce their disturbance in constrained motion as possible so as to improve entirely the effect of force control. The simulation results show that the proposed scheme has better force tracking performance and robustness to unknown parameters of the environment in comparison with the traditional force control method. References | Related Articles | Metrics

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Modification for theoretical model of ground surface roughness Xiu, Shi-Chao (1); Li, Chang-He (2); Cai, Guang-Qi (1) 2005, 26 (8):  770-773.  DOI: - Abstract ( 245 )   HTML   PDF (292KB) ( 2266 )   Most of the theoretic formulas to calculate the ground surface roughness are based on the geometrically generating interaction between grits and workpiece surface. Because of some simplifications especially the premise that the ground surface is formed completely just by cutting process, the effect of plastic upheaval deformation of workpiece surface on surface roughness is overlooked so as to cause the theoretic value of surface roughness to be often smaller than the real value. Analyzes the effect of plastic upheaval deformation on the maximum depth of the valley bottom of roughness profile and gives the plastic coefficients and modifies theoretical formulas of ground surface roughness. Compared with testing results, the calculated results by the formulas involving plastic coefficients are proved more accurate. References | Related Articles | Metrics

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Manufacturing information model during the product lifecycle Shu, Qi-Lin (1); Wang, Cheng-En (1) 2005, 26 (8):  774-777.  DOI: - Abstract ( 210 )   HTML   PDF (274KB) ( 1236 )   To define and express the data of each and every stage in the product lifecycle and maintain the interdependencies among the data, the product lifecycle is divided into five stages, i.e., demand analysis, conceptual design, engineering design, manufacturing and service/support. Then, a framework is proposed for the lifecycle model through logical mapping, which is set up taking advantage of all the data and documents relevant to the product and stored in decentralized databases to cover the five submodels corresponding to the five stages. Based on the framework, a manufacturing information model is developed for the product, including the information on parts' processing, assembly and manufacturer's technology resource. References | Related Articles | Metrics

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Experimental study on surface subsidence monitoring with D-InSAR in mining area Wu, Li-Xin (1); Gao, Jun-Hai (2); Ge, Da-Qing (2); Liao, Ming-Sheng (4) 2005, 26 (8):  778-782.  DOI: - Abstract ( 278 )   HTML   PDF (682KB) ( 755 )   Based on the quantitative analysis of phase compositions and its contributions to D-InSAR (Difference-Interferometric Synthetic Aperture Radar) monitoring, Tangshan City and Kailuan Mining Area, as the typical mining/industrial area in Eastern China, are selected as the experimental district for the application of D-InSAR to the monitoring and the dynamical analysis of surface subsidence. The 5-scene ERS1/2 SLC SAR data acquired from two temporal phases in 1997 and 1998 being selected as experimental data, the deformation in the line of sight was extracted separately by way of 2 pass and 3 pass D-InSAR By transforming the LOS deformation into vertical subsidence, the evolution of surface subsidence caused by underground coal mining and underground water exploitation was analyzed. The temporal decorrelation, spatial decorrelation and other error sources in D-InSAR monitoring in mining area were analyzed and discussed. As one of the key technologies for digital mine, it was suggested that the multi-temporal and the Connor Reflectors(or Plane Reflectors) could be applied in D-InSAR that is being used for the long-term surface subsidence monitoring in mining area. References | Related Articles | Metrics

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Immobilization process of flavobacterium sp. for bioremediation of contaminated surface water Xu, Xin-Yang (1); Zhang, Yi (1); Li, Hai-Bo (2); Li, Pei-Jun (2) 2005, 26 (8):  783-786.  DOI: - Abstract ( 233 )   HTML   PDF (355KB) ( 750 )   According to the characteristics of contaminated surface water, a strain of Flavobacterium sp. that could remove CODcr efficiently was picked out from river substrate sludge and then immobilized. Comparing several immobilization processed, an efficient kind of carrier was found, i.e., a gel made up of 10.5% PVA, 0.5% Na·Alg, 3% activated carbon and microdose of auxin. The results showed that the immobilized Flavobacterium sp. can remove 86.27% CODcr from contaminated surface water in 78 hours, much higher than the 59.65% removal rate by free ones. References | Related Articles | Metrics

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Sustainable utilization of water resources in littoral cities of Liaoning province Fu, Jian-Fei (1); Wang, En-De (1); Wang, Yi (2) 2005, 26 (8):  787-789.  DOI: - Abstract ( 203 )   HTML   PDF (2363KB) ( 533 )   Evaluates how the water resource were exploited in the littoral cities of Liaoning province in a fuzzy mode. The results show that the eigenvalue of exploitation level is 1.7632, i.e., a value between the first and second levels and approaching to capacity of water resource. Predictes the possible drought, increasing urban population, water consumption for people's daily life and grass consumption in littoral cities by establishing GM (1,1) and GM (1,2) models based on the gray system. The result shows that there will be droughts in 2004 and 2009, and the urban population will be up to 7.2 million in 2010 and 9.1 million in 2020, and the daily life water consumption and gross consumption will be up to 446 million ton and 980 million ton in 2010, respectively. It is thus estimated that there will be a keener contradiction between water demand and supply in these cities. References | Related Articles | Metrics

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Numerical simulation of fracture process of concrete under dynamic impact Zhang, De-Hai (1); Zhu, Fu-Sheng (1); Xing, Ji-Bo (2) 2005, 26 (8):  790-793.  DOI: - Abstract ( 273 )   HTML   PDF (428KB) ( 1084 )   The dynamic fracture process of concrete is simulated with the BPM2D (Beam-Particle Model in Two Dimensions) which is based on DEM in combination with FEM. In the BPM three types of beam are chosen to be the concrete specimens to simulate. The mechanical properties of the elements of each and every beam vary with their strain-rate and are randomly assigned according to Weibull distribution so as to model the initial heterogeneity of concrete at microscale level. The failure process of a concrete panel under dynamic impact was analyzed by this model. The stress wave propagation in concrete at different impact velocities was displayed. A comparison of the simulated results with experimental data declares that the BPM2D is available to simulate the dynamic failure of brittle materials. References | Related Articles | Metrics

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On the sustainable development during reconstruction of Liaoning old industrial base Gu, Xiao-Wei (1); Wang, Qing (1); Liu, Jian-Xing (1); Li, Guang-Jun (1) 2005, 26 (8):  794-797.  DOI: - Abstract ( 203 )   HTML   PDF (249KB) ( 586 )   Presents in detail the calculate results of the ecological footprints and bio-capacities in Liaoning Province and its 14 cities in the year 2001, as well as an analysis made to its ecological structure/system. A clear outlook is thus provided for the developing sustainability of the province. The results show that the ecological footprints, i.e., human land consumption, of all cities in Liaoning have exceeded their respective bio-capacities except for Jinzhou City, thus causing the high ecological deficit from which the per capita value of the deficit is up to 1.31 hm2·cap-1. The fact implies that the resource-exhausted development in the region has been in a relatively unsustainable state, especially the consumption of fossil fuels is found to be the root cause of the resource-exhausted ecological footprint which has been up to 1.63 hm2·cap-1 or 67.3% of the total. In the five cities with higher ecological deficits, i.e., Panjin, Anshan, Benxi, Liaoyang and Fushun, the ecological indicated by fossil fuel consumption are up to over 75% of their respective total. Based on the components and geographical distribution of ecological footprint, a strategic policy is proposed to lead Liaoning to develop in a more sustainable way. References | Related Articles | Metrics

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- - 2005, 26 (8):  798-800.  DOI: - Abstract ( 231 )   HTML   PDF (179KB) ( 944 )   - References | Related Articles | Metrics

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- - 2005, 26 (8):  801-804.  DOI: - Abstract ( 221 )   HTML   PDF (244KB) ( 1252 )   - References | Related Articles | Metrics

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- - 2005, 26 (8):  805-808.  DOI: - Abstract ( 199 )   HTML   PDF (2355KB) ( 534 )   - References | Related Articles | Metrics

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- - 2005, 26 (8):  809-812.  DOI: - Abstract ( 207 )   HTML   PDF (325KB) ( 791 )   - References | Related Articles | Metrics

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- - 2005, 26 (8):  813-816.  DOI: - Abstract ( 168 )   HTML   PDF (318KB) ( 364 )   - References | Related Articles | Metrics