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15 March 2007, Volume 28 Issue 3 Previous Issue    Next Issue
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Simplified identification method of takagi-sugeno fuzzy model Chang, Xiao-Heng (1); Jing, Yuan-Wei (1); Jiang, Xue-Mei (2); Liu, Xiao-Ping (1) 2007, 28 (3):  305-307.  DOI: - Abstract ( 436 )   HTML   PDF (154KB) ( 844 )   The identification problem of Takagi-Sugeno fuzzy model is discussed and as an improvement, a simplified method is proposed taking lines as the objective of data classification. According to a set of given input-output data, linear equations of the consequent of the model are obtained by Hough transform, with conclusive parameters identified. Based on the linear segments, the input data are classified. Considering the proximity of input data to relevant linear segment and how the adjacent linear segment affects the input data, the consequent parameters of the model are identified. The proposed method needn't cyclic data processing, thus reducing greatly the computation. A simulation example shows the effectiveness of the method to T-S fuzzy model identification. References | Related Articles | Metrics

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Mathematical model of hepatitis B and its control Yang, Guang (1); Zhang, Qing-Ling (1); Liu, Pei-Yong (1) 2007, 28 (3):  308-311.  DOI: - Abstract ( 352 )   HTML   PDF (177KB) ( 999 )   Tries to develop a mathematical model to express how the hepatitis B virus (HBV) spreads over and transforms from a state into other one by a set of differential equations. A conclusion can be drawn from it that if there is a positive equilibrium point found in the model, the disease elimination point is unstable and the infectious disease will spread over. It means that the disease or the model should be controlled effectively by way of immunization, i.e., isolating infants from their mothers and immunizing all infants. A Lyapunov function is therefore constructed and, according to the relevant theory of stability, it is proved that the model is globally stable at the disease elimination point after the immune control and, eventually, HBV will be eliminated. In addition, the conditions are obtained for extinction of HBV. References | Related Articles | Metrics

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Novel identifier based on ADACD and model reference adaptive controller Luo, Yan-Hong (1); Zhang, Hua-Guang (1) 2007, 28 (3):  312-315+324.  DOI: - Abstract ( 224 )   HTML   PDF (224KB) ( 522 )   The action-dependent adaptive critic design (ADACD) is introduced into the identification of nonlinear systems to obtain the best model. A total evaluation function is defined to express the total identification error of a system within the time it has experienced, then a critic network is constructed to approximate to this evaluation function. And an identifier network is further constructed taking its output as the critic network input. In such a way the best model can be obtained by minimizing the critic network output. Here the parameter adaptation rule is based on minimizing the critic network output, i.e., the total identification error of a system within the time it has experienced, instead of minimizing the instant error. As a result, the convergence rate is quickened remarkably with more accurate identifiability. After obtaining the model of the system, the design of the model reference adaptive controller (MRAC) for this model is studied by using neural networks. The simulation results showed that the performance of this novel identifier is excellent, and the MRAC based on it can make sure that a system to be controlled tracks the reference model quickly and stably. References | Related Articles | Metrics

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Method to recognize character's color polarity of text region Sun, Hong-Xing (1); Zhao, Nan-Nan (2); Wang, Rong (3); Xu, Xin-He (1) 2007, 28 (3):  316-319.  DOI: - Abstract ( 241 )   HTML   PDF (324KB) ( 677 )   Characters in a text region may have different color polarities. To convert correctly the image with grayscale in an accepted text region into the OCR-ready binary image, a method is proposed to classify then recognize the color polarity of characters in a text region. The gray-gradient co-occurrence matrix of the text region is calculated, and the optimum thresholds of segmented grayscale and gradient are found quickly according to the objective function. Then, the feature vector is extracted from the gray-gradient co-occurrence matrix and fed into neural network to classify the color polarity. All the characters in the text region are finally segmented according to the classification of color polarities. Experimental results showed that the proposed method can recognize correctly different color polarities of characters in the background with different complexities. References | Related Articles | Metrics

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Qos rerouting mechanism in NGI Wang, Xing-Wei (1); Chen, Mo (1); Gao, Nan (1); Huang, Min (1) 2007, 28 (3):  320-324.  DOI: - Abstract ( 198 )   HTML   PDF (1215KB) ( 513 )   Based on the features of NGI and users' handoff, a QoS rerouting mechanism is proposed according to fuzzy theory. Introducing the membership function of the bandwidth available to link and the same functions of the delay, delay jitter, error rate and hop count of path and the link's quality evaluation table, a fuzzy evaluation is done for the specific parameters. Then, the path overlapping factor and path selection factor are defined to evaluate the quality of the path, and the concrete steps of QoS rerouting are designed. An NS2-based simulation is thus implemented and the results show that the proposed mechanism is feasible and effective, and it can satisfy users' QoS demands with rerouting signal overhead reduced. References | Related Articles | Metrics

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Prediction modelling method for non-linear and non-stationary time series Lin, Shu-Kuan (1); Yang, Mei (1); Qiao, Jian-Zhong (1); Wang, Guo-Ren (1) 2007, 28 (3):  325-328.  DOI: - Abstract ( 637 )   HTML   PDF (127KB) ( 2155 )   A prediction modelling method was proposed for non-linear and non-stationary time series, based on empirical mode decomposition (EMD) and support vector regression (SVR). The time series was decomposed into several intrinsic mode components (IMCs) via EMD so as to make every component stationary. Then in view of the stationary time series, a prediction model was developed correspondingly for each and every IMC on SVR basis, and these prediction models were non-linearly combined together by use of SVR again to form the final prediction model for non-linear and non-stationary time series. Both simulative experiment and engineering application showed that the proposed method has higher precision in comparison with the conventional SVR-based modelling method, i.e., effective to non-linear and non-stationary time series prediction. References | Related Articles | Metrics

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Task scheduling in grid environment based on immune genetic algorithm Chen, Ting-Wei (1); Zhang, Bin (1); Hao, Xian-Wen (1) 2007, 28 (3):  329-332.  DOI: - Abstract ( 285 )   HTML   PDF (227KB) ( 842 )   Studies the task scheduling in grid environment and proposes a task scheduling mechanism, i.e. each and every possible task scheduling scheme is expressed as a task-resource assignment graph, thus converting the task scheduling problem into a graphically optimal selection problem. Then, to find the optimal solution quickly and accurately, a task scheduling algorithm based on immune genetic algorithm is proposed to implement the optimal selection. This algorithm takes the longest path in the task-resource assignment graph as an antigen and every task-resource assignment as a corresponding antibody. Experimental results show that the approach proposed is effective in the capability of global optimization and significantly improves the convergence rate. References | Related Articles | Metrics

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Rear-vehicle detection combining both knowledge-based and appearance-based methods Wen, Xue-Zhi (1); Zhao, Hong (1); Wang, Nan (2); Yuan, Huai (2) 2007, 28 (3):  333-336.  DOI: - Abstract ( 276 )   HTML   PDF (190KB) ( 926 )   There is unavoidably a limit to either knowledge-based or appearance-based methods when using any of them singly to detect the existence of vehicles. An algorithm combining both of them is therefore proposed to detect rear-vehicles in static images. First, the ROIs (regions of interest) obtained from segmentation algorithm are filtered which are regarded as belonging to background by using knowledge-based methods such as the shadow underneath a vehicle and color information. Then, the vehicles are detected with appearance-based methods on the remains. The detection results of vehicles traveling on highways, urban common roads and urban narrow roads under various illumination conditions on daytime indicated that the proposed algorithm has better reliability and higher adaptability than either of the algorithms singly based on knowledge or appearance. References | Related Articles | Metrics

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Linear conjugate semi-blind multiuser detection based on subspace tracking Meng, Yan (1); Wang, Jin-Kuan (1); Song, Xin (1); Han, Ying-Hua (1) 2007, 28 (3):  337-340.  DOI: - Abstract ( 264 )   HTML   PDF (171KB) ( 541 )   With the subspace-based minimum-mean-square-error (MMSE) semi-blind multiuser detection investigated in-depth, a linear conjugate MMSE semi-blind multiuser detector based on subspace tracking algorithm is proposed against the performance degradation induced by signal subspace estimation errors in the conventional algorithm for multicarrier CDMA (MC-CDMA) uplink. Combining the subspace method with the idea of linear conjugate, a linear conjugate MMSE detector is designed on the basis of subspace method by a newly defined signal subspace. Moreover, the orthogonal projection approximation subspace tracking (OPAST) algorithm is used for adaptive subspace estimation. Simulation results showed that the proposed algorithm can improve the signal-to-interference-plus-noise-ratio (SINR) output and reduce the bit-error-rate (BER) performance effectively, compared with previous MMSE semi-blind multiuser detection algorithms. References | Related Articles | Metrics

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Trust valuation model in mobile Ad hoc network Feng, Jian-Xin (1); Tang, Jia-Fu (1); Wang, Guang-Xing (1) 2007, 28 (3):  341-344.  DOI: - Abstract ( 242 )   HTML   PDF (150KB) ( 628 )   To partition structurally the mobile Ad hoc network (MANET) in view of its security management and ensure its effective operation and management, a trust valuation model was developed according to the definition of trust. Introducing the service level management of entity behavior and measuring the success/failure frequencies of different kinds of entity behavior in trusting relationship, the direct, recommendation and node trust or confidence is defined separately. The application results showed that the model is adaptive to mobile Ad hoc network and especially it can compensate for the defect that there is no detection to malicious nodes in other existing clustering algorithms. References | Related Articles | Metrics

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Texture formation of IF steel sheet hot-rolled in ferrite region and its transformation during cold-rolling and annealing Li, Si-Jun (1); Qu, Jia-Hui (1); Wang, Fu (1); Zuo, Liang (1) 2007, 28 (3):  345-348.  DOI: - Abstract ( 240 )   HTML   PDF (372KB) ( 911 )   Systematically investigated and discussed texture formation mechanism of IF steel sheet hot-rolled in ferrite region and its transformation mechanism during cold-rolling/annealing by means of the microstructure observation and crystallographic orientation distribution function (ODF). The results showed that the strong α-fibrous texture and the weak γ-fibrous texture are both attained simultaneously during hot-rolling in ferrite region by alternating slip system with a bit of recrystallized grains found; both the fibrous textures are strengthened during cold-rolling under the joint action of dislocation movement by slip, grain rotation and intracrystalline shear bands; the formation of recrystallization structure/texture is mainly controlled by the mechanism of strong oriented nucleation and weak selective growth during annealing. References | Related Articles | Metrics

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Effect of controlled cooling on microstructure refinement and mechanical properties of pipeline steel X65 Zhang, Hong-Mei (1); Xu, Yun-Bo (1); Liu, Zhen-Yu (1); Wang, Guo-Dong (1) 2007, 28 (3):  349-352+377.  DOI: - Abstract ( 268 )   HTML   PDF (1457KB) ( 589 )   The process of the controlled cooling after rolling was laboratorially studied on a 0450 rolling mill with the low-carbon low-alloy pipeline steel X65 as specimens to provide further an experimental and theoretical reference for actual industrial production. TEM images showed that the typical morphology of acicular ferrite is a very fine sub-structure with high dislocation density and part of ultra-fine ferrite, of which the small M/A islands and cementite are dispersing on the matrix. Experimental results showed that not only the microstructure is refined obviously but also the volume fraction of acicular ferrite increases and the mechanical properties are improved with decreasing coiling temperature or increasing cooling rate. The flexible rolling is thus available to the X65 ferrite-pearlite steel through controlled cooling after rolling, by which both its microstructure and mechanical properties can be improved so significantly even superior to the performance requirements for the Grade X70 pipeline steel. References | Related Articles | Metrics

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Numerical simulation of semi-solid forming process of A356 alloy Lu, Gui-Min (1); Zhao, Da-Zhi (1); Wang, Ping (1); Cui, Jian-Zhong (1) 2007, 28 (3):  353-356.  DOI: - Abstract ( 242 )   HTML   PDF (381KB) ( 725 )   The FEA software ANSYS was applied to the numerical simulation coupling temperature field with velocity field to analyze the effect of mold filling temperature on the flow and temperature distribution of semi-solid slurry of A356 alloy during thixo-forming. The results showed that the semi-solid slurry is stable in filling process without spouting, air entrapment and hot spot area found in temperature distribution if the mold filling temperature is 590°C with an injecting rate 5 m/s. Such conditions are ideal to the forming of semi-solid A356 alloy slurry because they are beneficial to getting fully filled semi-solid parts with clear contour and compact microstructure. The technological parameters obtained from numerical simulation are verified by tests. References | Related Articles | Metrics

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Rotational bending fatigue behavior of ni-based casting superalloy K435 at room temperature Guo, Xiao-Guang (1); Guo, Jian-Ting (2); Zhou, Lan-Zhang (2); Yang, Hong-Cai (1) 2007, 28 (3):  357-360.  DOI: - Abstract ( 282 )   HTML   PDF (672KB) ( 604 )   Investigates the rotational bending fatigue behavior of Ni-based casting superalloy K435 at room temperature where the stress ratio of specimen equals-1 and specimens are rotating at 5000 r/min(83.3 Hz). The stress-fatigue life curve relevant to rotational bending was obtained and the fatigue limit was measured to be 220 MPa. The fatigue fracture surface morphology was observed by SEM, and the fatigue cracks were found mainly initiated at the defects on specimen surface and/or near its sub-surface. The micrographics showed that the fracture is mainly due to the crack initiation, steady crack propagation and instantaneous fracture. Discusses the mechanism of the fatigue fracture of K435 superalloy and observes the change of its microstructure by TEM. References | Related Articles | Metrics

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Multi-fluid mathematical model for blast furnace and its solution Chu, Man-Sheng (1); Guo, Xian-Zhen (2); Shen, Feng-Man (1); Yagi, Jun-Ichiro (3) 2007, 28 (3):  361-364.  DOI: - Abstract ( 282 )   HTML   PDF (318KB) ( 968 )   To understand, control and improve the blast furnace process, more efforts are made to develop mathematical models relevant to it, and the multi-fluid blast furnace model is the latest reaction-kinetic one for the whole blast furnace. It was based on the multi-fluid theory, kinetics, transport phenomena theory and computational fluid dynamics, with the mutual interphase interactions fully taken into account. The application results revealed that the multi-fluid model is a complicated, comprehensive and effective tool for blast furnace process simulation available to both 2-D and 3-D in-furnace phenomena and accurate prediction of the operational parameters under given conditions. References | Related Articles | Metrics

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Study on improving the softening-melting properties of MgO-bearing iron ores Jiang, Xin (1); Wu, Gang-Sheng (1); Li, Guang-Sen (1); Shen, Feng-Man (1) 2007, 28 (3):  365-368.  DOI: - Abstract ( 272 )   HTML   PDF (492KB) ( 870 )   To improve the softening-melting properties of iron ores, some measures are suggested to take to add properly MgO in BF operation especially the new process in which the MgO-bearing pulverized coal is injected from tuyere under the condition that the MgO content in slag should be kept up. Experimental results showed that the decrease in MgO content may decrease the temperature range in softening-melting zone of the sinter. To improve the softening-melting properties of the sinter, the structure of furnace charge is suggested to change reasonably, mixing the low-MgO-content sinter with magnesite or high-MgO-content sinter with acidic pellet. The former and latter can decrease the temperature range of the softening-melting zone of furnace charge by 20-30°C and 50-100°C, respectively. References | Related Articles | Metrics

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Study on desirable flowrate of roasting gas in pelletizing shaft furnace Dong, Hui (1); Cai, Jiu-Ju (1); Wang, Guo-Sheng (2); Wang, Feng (3) 2007, 28 (3):  369-372.  DOI: - Abstract ( 269 )   HTML   PDF (113KB) ( 966 )   Studies thermodynamically the key problems of the high capacity/efficiency pelletizing shaft furnace (PSF), i.e., flowrate of roasting gas in PSF as desired for a constant output. The desirable gas-solid water equivalent ratio was defined by the equations of gas-particle heat exchange and thermal equilibrium, then the problem how the desirable roasting gas blasts into the packed beds was studied. Some conclusions were drawn as follows. For the PSF whose main raw material is magnetite, the desirable water equivalent ratio is about 0.71-0.72, and the desirable water equivalent ratio should be about 0.75-0.80 if considering the uniformity of roasting gas in PSF. In addition, some measures should be taken to ensure the desirable water equivalent ratio in PSF, such as enlarging the inlets of roasting gas, optimizing the structure of combustion chambers, removing dust by sidewise induced-draft and gravity and improving conventional adjustment of PSF. References | Related Articles | Metrics

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Coke quality prediction models Xie, Hai-Shen (1); Liu, Yong-Xin (2); Lu, Qing (2); Meng, Jun-Bo (2) 2007, 28 (3):  373-377.  DOI: - Abstract ( 413 )   HTML   PDF (309KB) ( 1400 )   Metallurgical coke as the permeable backbone in furnace becomes more and more important with increasing capacity of blast furnace and developing technique of pulverized coal injection for oxygen-enriched melting. Coke quality is urgently required to improve in iron plants, and a set of accurate coke quality prediction models is therefore developed for coke production on the basis of comparison and analysis of existing relevant prediction models. By the analysis and regression of experimental data from a small-size coke oven in combination with linearization and empirical modification, the mathematical models of blending are developed for coking process, thus obtaining the prediction models of coke ash/sulfur, mechanical properties (M40/M10) and thermal properties (CRI/CSR). Errors between prediction and measurement are below 6%, available to meet production demand for coke making and provide theoretical foundation for exact coal blending. References | Related Articles | Metrics

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Behavior of linear expansion of corundum-spinel castables in sintering process Yu, Jing-Kun (1); Du, Jing-Yun (1); Ma, Bei-Yue (1); Jiang, Mao-Fa (1) 2007, 28 (3):  378-380.  DOI: - Abstract ( 221 )   HTML   PDF (692KB) ( 535 )   The linear expansion rate was determined by the φ10 mm × 50 mm samples formed by fused corundum, magnesia, silica micropowder and aluminate cement at 750-1 450°C. The effects of the grain size of fused corundum and amounts of magnesia, cement and silica micropowder as additives on the behavior of linear expansion of the corundum-spinel castables in sintering process were studied. The results showed that they affect obviously the behavior, i.e., increasing the grain size of fused corundum and amount of silica micropowder will inhibit the linear expansion rate, while increasing the amounts of magnesia and cement the linear expansion rate tends to increase. References | Related Articles | Metrics

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Investigation on process flow of high-density magnesia Li, Huan (1); Su, Li (1); Yu, Jing-Kun (1) 2007, 28 (3):  381-384.  DOI: - Abstract ( 247 )   HTML   PDF (307KB) ( 1236 )   Magnesia was used as starting material to prepare MgO specimens the way it was lightly roasted at 850°C for 2 hr to form MgO which was then hydrated, ground, filtered, extracted and dried to become Mg(OH)2 from which the powdered MgO with different activities were obtained at different temperature and, finally, the φ20 mm × 10 mm cylindrical MgO or magnesia specimens were provided through briquetting and sintering. How the fineness of powdered magnesia due to grinding, briquetting pressure and light roasting temperature affect the bulk density of sintered magnesia were investigated through tests. The results showed that both the grinding operations before and after the light roasting at 600°C of Mg(OH)2 to become powdered magnesia affect significantly the bulk density of sintered magnesia, while the briquetting pressure affects it not much. So, high-density magnesia can be obtained under the conditions that there are two grinding operations mentioned above, the briquetting pressure to form specimens is 200 MPa and sintering at 1 600°C for 3 hr. Such a magnesia shows TO (MgO) = 97.5%, w(CaO):w(SiO2)>2 and bulk density = 3.47g/cm3. References | Related Articles | Metrics

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Study on visual optimization design for modern machinery Sun, Wei (1); Ren, Zhao-Hui (1); Yu, Tao (1); Wen, Bang-Chun (1) 2007, 28 (3):  385-388.  DOI: - Abstract ( 195 )   HTML   PDF (270KB) ( 1002 )   Based on the achievements of early works, a modern-machinery-oriented visual optimization design (VOD) is put forward trying to take visualization as design means to inspect and optimize the performance of a mechanical product at every aspect. Analyzing the characteristics in designing modern machinery, the connotation and research contents to be studied, technical flow, key techniques, R&D of supporting software and application rules of VOD are all determined so as to build a theoretical frame of methodology. Taking a large-size linear vibration screen as example, the VOD proposed was applied to studying its assembling process, dynamics performance, kinematic state and working process, and the result showed the validity of the VOD. In addition, the application results revealed that the VOD can improve the design quality of products in an all-round way. References | Related Articles | Metrics

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Position error analysis of drive rod hinges on a kind of 3-DOF parallel machine tools Hu, Ming (1); Tian, Wen-Yuan (1); Cai, Guang-Qi (1) 2007, 28 (3):  389-392.  DOI: - Abstract ( 207 )   HTML   PDF (247KB) ( 854 )   To improve the kinematic precision of 3-DOF parallel machine tools, the problem how the position error of the drive rod hinges affects the precision should be solved first. A relevant hinge position error model is therefore developed introducing the superposition method and taking the 3-PTP parallel machine tool developed by the Northeastern University as modeled object. Matrix norm is used to analyze the influence of position error of drive rod hinges on the kinematic precision of the end of moving platform, and the result shows that the greater value of the structural parameter A is disadvantageous to the minimum value of the position error of moving platform in working space but less disadvantageous to the maximum value. The error model proposed lays down a foundation on which the mechanism design parameters of parallel machine tools can be optimized further with the error compensation available. References | Related Articles | Metrics

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Study on properties of grinding fluid jet and nozzle position limit during quick-point grinding Xiu, Shi-Chao (1); Li, Chang-He (2); Pang, Zi-Rui (1); Cai, Guang-Qi (1) 2007, 28 (3):  393-396.  DOI: - Abstract ( 237 )   HTML   PDF (161KB) ( 568 )   Quick-point grinding is a new type of high and super-high speed grinding process with excellent machining performance provided. In such a grinding process there is a high-speed airflow rotating around the edge of grinding wheel to hinder the grinding fluid from injecting into the ground area so as to decrease its entering rate into the area and affect the cooling effect and greenness during grinding. Analyzing the structure and properties of grinding fluid jet, the velocity distribution field of round turbulent jet is discussed theoretically and simulated. Based on the equipressure principle, a mathematical model is developed for the jet velocity at grinding fluid nozzle, which enables the coolant to pass through the high-speed airflow and enter into the ground area. According to the analysis of the grinding fluid velocity in the jet core, an engineering formula is given to calculate the position limit of nozzle during quick-point grinding, as well as a practical design example for the experimental grinder. References | Related Articles | Metrics

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Design for shields of NC machine tool SSCK40 Liu, Yang (1); Zhu, Chun-Xia (1); Huang, Ya-Li (1); Cai, Guang-Qi (1) 2007, 28 (3):  397-400.  DOI: - Abstract ( 392 )   HTML   PDF (324KB) ( 1389 )   Based on ergonomics, a virtual appearance design was carried out for the shields of the NC machine tool SSCK40. The whole design process was completed by such softwares as AUTOCAD, SolidWorks and PhotoShop for 2-D drawing, 3-D modeling and the entire appearance design of the NC machine tool, respectively. The virtual design process proposed is proved available to shorten the R&D period of new products and decrease production cost, thus enhancing the competitiveness of the NC machine tool on market. References | Related Articles | Metrics

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Detectability analysis of residual control charts for monitoring change in mean deviation Cui, Jing-Wei (1); Xie, Li-Yang (1); Liu, Xiao-Xia (1) 2007, 28 (3):  401-404.  DOI: - Abstract ( 227 )   HTML   PDF (159KB) ( 548 )   When using control charts to monitor a process, a necessary assumption is that any two of the observations in the process are independent with each other. However, such observations are frequently autocorrelation in practice. If the residuals in the autocorrelation process satisfy the conditions that they are independent random variables and in the same distribution, applying control charts to residual monitoring is one of the effective ways to control the autocorrelation process. Taking the detectability index and average run length as evaluation indices, the detectability of residual control chart to the change in mean deviation is analyzed when the correlation process is expressed by the time series model AR (1). The results show that the EWMA residual control chart (φ&le1-λ) is highly sensitive to small mean deviation but lower to great mean deviation than Shewhart control chart when the process parameter φ<0. References | Related Articles | Metrics

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Dynamic scheduling optimization of dual-resource based on Petri net and GASA Tao, Ze (1); Sui, Tian-Zhong (1); Xie, Li-Yang (1); Liu, Xiao-Xia (1) 2007, 28 (3):  405-409.  DOI: - Abstract ( 213 )   HTML   PDF (627KB) ( 599 )   Petri net with controller is used to model the discrete events in flexible job shop scheduling. The model is available to not only show the multiprocessing paths for the jobs to be processed and resource constrains on a flexible line, but also depict the system characteristics, such as equipment maintenance and different types of priorities. The scheduling results are based on GASA (genetic and simulated annealing algorithm) and used to address the dynamic optimal scheduling in the job shop where the machines and workers are both constrained. Taking minimizing the make-span as the objective of scheduling, an optimal or suboptimal solution to the scheduling is found through various genetic and simulated annealing operations as crossover, mutation, probabilistic updating and re-assignment strategy; especially the GASA algorithm which will provide renewed schedule rapidly after an unexpected disturbance happened in job shop. Simulation results based on some job shop scheduling show that the GASA is efficient and robust. References | Related Articles | Metrics

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Classification and recognition based on improved SVM for surface defects of cold strips Wang, Cheng-Ming (1); Yan, Yun-Hui (1); Chen, Shi-Li (2); Han, Ying-Li (1) 2007, 28 (3):  410-413.  DOI: - Abstract ( 236 )   HTML   PDF (227KB) ( 586 )   Aiming at the existing problems in pattern recognition of surface defect images of cold strips, a classification and recognition method is proposed to solve them, based on improved support vector machine (SVM). According to the features in recognizing those surface defect images and on the basic principle of SVM, the method provides an effective improvement to the progressively immediate inference SVM, thus designing a pattern recognition classifier for those surface defect images. The structure of the classifier is confirmed by experiments, with a method given to choose relevant parameters. Experimental investigation was carried out on computer aiming at several typical defect images which were found frequently in site, and the results showed that the classifier based on the improved SVM can solve the problems the conventional SVM is unable to solve, such as poor generality and decreasing accuracy when the gap between two classes is too narrow. In addition, the classifier provides higher adaptability and accuracy. References | Related Articles | Metrics

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Simulation of virtual prototype of ABS braking system and braking performance Song, Gui-Qiu (1); Jiang, Ming (1); Li, Hua-Qiang (1) 2007, 28 (3):  414-417.  DOI: - Abstract ( 215 )   HTML   PDF (218KB) ( 641 )   Simulation of ABS braking system was carried out with its virtual prototype the way the slip coefficient was taken as control parameter and the real-time control function of ABS was realized by the joint simulation through MATLAB and ADAMS. The simulation of velocity and braking distance is realized on the same virtual prototype model, and the result showed a quadratic functional relationship between car's velocity before braking action and braking distance. Discusses the impact of the ABS with 3 and 4 control channels on the directional stability during braking and braking distance. It was revealed that when emergency braking the braking distance is shortest if the 4-channel ABS works independently, while the distance becomes longer if the 3-channel ABS works independently. However, the deflection torque to a car is smaller with better directional stability when the car is traveling on an asymmetric road and in emergency brake application with a 3-channel ABS. References | Related Articles | Metrics

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Double-objective detection based on neural network for driver's alert level Yang, Ying (1); Sheng, Jing (1); Yang, Jia (2); Zhou, Wei (1) 2007, 28 (3):  418-421.  DOI: - Abstract ( 219 )   HTML   PDF (234KB) ( 771 )   Based on the single-objective detection, a double-objective detection is proposed for driver's alert level, i.e., the states and changes of both eyes and mouth of a driver are taken as the drowsy discriminance during monitoring a driver' s fatigue through his/her entire facial image when traveling. In this way both the characteristic vectors of eyes and lip of a driver are sequentially input into a modified BP network. Then, the region matching algorithm is introduced to detect comprehensively the alert level of a driver in accordance to the quantified evaluation indices showing how he/she is feeling fatigued. VC++ is used to develop an algorithm software to monitor driver' s fatigue, with which a simulation test is carried out. Test results show that the proposed double-objective detection system can monitor and identify accurately a driver' s alert level with high fault tolerance provided. References | Related Articles | Metrics

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Forced collection applied to gas flow containing high-mass-concentration dust in ESP electric field Hao, Wen-Ge (1); Wang, Bao-Jun (1) 2007, 28 (3):  422-425.  DOI: - Abstract ( 232 )   HTML   PDF (188KB) ( 596 )   Discusses theoretically and experimentally how to improve the efficiency of dust collection by use of ESP of which the efficiency is actually low until now. It was proved that there is a mass concentration gradient in dust distribution within the electric field by way of a mathematic analysis of the dust transfer model and the sectional measurement of dust mass concentration, i.e., the closer the dust to the plate electrode, the higher the mass concentration. The dust emission rate can be significantly decreased at ESP outlet when the gas flow containing high-concentration dust is sucked out through a suction opening at the end of ESP's plate electrode and the dust thus collected is then gathered into high-efficiency bags or treated secondarily at ESP inlet as the gas flow is cycled there. In addition, such a forced suction can reduce effectively the secondary dust flying due to beating/shaking the dust collecting plate. Analyzing the flow function at suction opening where the flowrate is constant, the relationship between suction height and efficiency of dust collection is revealed. References | Related Articles | Metrics

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Collecting low-resistivity dust with electrostatic precipitator Hao, Wen-Ge (1); Dai, Li-Yan (1); Hu, Xiao-Min (1); Wei, Xue-Ling (1) 2007, 28 (3):  426-429.  DOI: - Abstract ( 294 )   HTML   PDF (1187KB) ( 740 )   To solve the problem of collecting low-resistivity dust with ESP, a method is proposed to coat the ESP plate electrode surface with a special conductive compound so as to form a coating with a certain resistivity. Compares the coated plate electrodes with uncoated ones to discuss their discharge characteristics. The result showed that the ESP with coated plate electrode is available to collect low-resisitivity dust as long as the resistivity of the coating is between 105 Ω·cm and 109 Ω·cm. A formula is deduced to calculate the resistivity of the coating on the basis of the proposed mathematical model, by which the proportion of the conductive powder to be mixed in the compound can be calculated accurately. A contrast experiment was done for the dust-collection performance of ESP with and without such a coating by use of the model, and the ESP with coated surface of plate electrode is evidently superior to that with uncoated surface in dust collection efficiency. References | Related Articles | Metrics

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FEM analysis of associated and non-associated flow rules in theory of slip line field Kong, Wei-Xue (1); Deng, Chu-Jian (2); Rui, Yong-Qin (1); Zheng, Ying-Ren (2) 2007, 28 (3):  430-433+453.  DOI: - Abstract ( 273 )   HTML   PDF (1482KB) ( 1284 )   As shown in the theory of generalized plastic mechanics, the associated flow rule is just a particular case of non-associated flow rule. It is proved theoretically that in respect of non-associated flow rule the angle included by velocity vector and failure plane is ψ instead of ψ/2 that is usually used now, thus clarifying the misunderstanding on the two different flow rules in the theory of slip line field. Furthermore, the FEM limit analysis also proves that the stress slip line, ultimate load and velocity slip line are all the same if they are obtained by either associated or non-associated flow rule, but only the velocity vector shows difference. The result indicates that FEM limit analysis is available to not only solve accurately the geotechnical problem of ultimate load on foundation but also support the clarification of the difference between associated and non-associated flow rules used in the theory of slip line field. References | Related Articles | Metrics

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Time series analysis of ecological footprint in Tieling city Zhang, Bo (1); Wang, Qing (1); Gu, Xiao-Wei (1); Li, Guang-Jun (1) 2007, 28 (3):  434-437.  DOI: - Abstract ( 165 )   HTML   PDF (252KB) ( 850 )   Analyzes theoretically the ecological footprint and ecological capacity of Tieling City from 1995 to 2004. The result shows that in this time period the average ecological footprint, capacity and deficit were 2.07, 1.22 and 0.851 hm2/cap, respectively, i.e., the city is in a state of unsustainable development. In the total ecological footprint the largest proportion resulting from energy consumption is about 60%, up to 63% in 2003 down to 59% in 1999. The second largest one is cropland, about 26%-31% and, sequentially, the land for building, grazing land, aquatic area and forest land. Taking account of the footprint intensity and ecological efficiency of the city, an ecological strategy is proposed for its sustainable development with some advice given. References | Related Articles | Metrics

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Study on urban traffic ecological footprint in Shenyang city Sun, Peng (1); Wang, Qing (1); Liu, Jian-Xing (1); Gu, Xiao-Wei (1) 2007, 28 (3):  438-440.  DOI: - Abstract ( 201 )   HTML   PDF (787KB) ( 591 )   The theory and method of ecological footprint (EF) were used to study quantitatively the sustainable development of urban traffic in Shenyang City. The results showed that in the year 2004 the urban traffic EF is 35 × 104 hm2 among which the footprint of the energy consumption is up to 99%, while the road surface is only 1%. In view of the structure of EF, car and taxi are 53% (about 18.5 × 104 hm2), and 16% (about 5.61 × 104 hm2), respectively. However, in view of the ecological efficiency of urban traffic, bus is the top one up to 3.06 × 104 person-time·hm-2, while car is the lowest one of all kinds of vehicles, only 0.12 × 104 person-time·hm-2. The environmental pressure index of traffic shows that car is the highest in various vehicles, near to 8.38 × 10-4 hm2/person-time, while bus is the lowest, only 0.33 × 10-4 hm2/ person-time. References | Related Articles | Metrics

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Robust operation model for electronic supply chain with uncertain demands Xu, Jia-Wang (1); Huang, Xiao-Yuan (1) 2007, 28 (3):  441-444.  DOI: - Abstract ( 233 )   HTML   PDF (816KB) ( 601 )   A single-objective robust operation model is proposed for an electronic supply chain that consists of multiple suppliers and customers with uncertain demands, in which every supplier can directly supply its products to the customers with uncertain demands or supply them through electronic marketplace. What the supply chain operation pursues is to minimize the total system cost. Uncertain demands are expressed as a scenario set with given probability, and the supply chain operation model is thus developed by using the robust optimization based on scenario analysis. To verify the robustness of the model and the effect of the number of operation objectives on the validity of the modelling process, a numerical example is performed using the data as shown in earlier works. The results showed that the model proposed is robust to uncertain demands and the number of operation objectives has no effect on the validity of the modelling process. References | Related Articles | Metrics

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Ecological safety comprehensive evaluation in mineral-resource enterprises based on AHP Zheng, Yun-Hong (1); Li, Kai (1) 2007, 28 (3):  445-448.  DOI: - Abstract ( 239 )   HTML   PDF (770KB) ( 593 )   Based on the theories of sustainable development and regional ecological safety, the connotation and evaluation method of the ecological safety of a business relying on mineral resource are studied. AHP is confirmed as the evaluation method to the ecological safety of the business with an evaluation index system set up for its ecological safety. This index system consists of twenty indexes covering the environmental pressure and quality and controllability of resource environment, thus ensuring the scientificity and integrity of the index system. According to the characteristics and level/standard of each and every evaluation index, the evaluation criterion and corresponding grades are given. An application example is given showing the feasibility and effectiveness of the proposed approach. References | Related Articles | Metrics

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- - 2007, 28 (3):  449-453.  DOI: - Abstract ( 213 )   HTML   PDF (200KB) ( 597 )   - References | Related Articles | Metrics

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- - 2007, 28 (3):  454-456.  DOI: - Abstract ( 197 )   HTML   PDF (122KB) ( 871 )   - References | Related Articles | Metrics