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15 January 2007, Volume 28 Issue 1 Previous Issue    Next Issue
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Reliable H∞ control of dynamic output feedback for linear systems Yao, Bo (1); He, Xin (2); Men, Bo (1); Zhang, Si-Ying (1) 2007, 28 (1):  1-5.  DOI: - Abstract ( 210 )   HTML   PDF (192KB) ( 442 )   Studied the reliable H∞ control design of dynamic output feedback control for linear systems on the basis of the linear matrix inequality (LMI). During the design a continuous fault model that is more practical than discrete fault one is developed. The reliable control systems designed can ensure the asymptotic stability and H∞ performance of an actuator in operation whether a fault happens or not. Under the conditions that an H∞ performance bound is given when a fault happens, the H∞ performance of a system is optimized in case no fault happens. A numerical example is also given to illustrate the design procedure and its effectiveness. References | Related Articles | Metrics

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Stability analysis of stochastic Cohen-Grossberg neural networks with mixed time delays Wang, Gang (1); Zhang, Hua-Guang (1); Fu, Dong (2) 2007, 28 (1):  6-9.  DOI: - Abstract ( 247 )   HTML   PDF (166KB) ( 653 )   Mean square exponential stability of Cohen-Grossberg neural networks with time-varying delays and distributed time delays is analyzed. By using differential formula and Lyapunov functional, a new delay-independent sufficient condition for exponential stability is derived. By Itoˆ differential formula, the stochastic derivative of Lyapunov functional along the considered neural network is obtained. Finally, a numerical example is given to demonstrate the usefulness of the proposed stability criteria. To the best of our knowledge, there are few results about the mean square exponential stability analysis of Cohen-Grossberg neural networks with time-varying delays and distributed time delays. Due to the representation of Cohen-Grossberg neural networks, it is significant to study its exponential stability. References | Related Articles | Metrics

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A solution to fractional order linear systems Zhao, Chun-Na (1); Xue, Ding-Yu (1) 2007, 28 (1):  10-13.  DOI: - Abstract ( 243 )   HTML   PDF (1434KB) ( 1399 )   Defines the factional order calculus and clarifies its basic characteristics because the fractional order systems have been used much wider than before in application. Generally the characteristic equation of a fractional order system is not a real polynomial but a pseudo-polynomial function of complex variable with fractional exponent, which can be approximated and converted into a high-order integral exponent system so as to study it by existing control approaches. A method is thus proposed to analyze fractional order linear systems on the basis of the definition of fractional calculus, and its effectiveness is verified via a simulation example. References | Related Articles | Metrics

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ABR traffic control using PSO-PID controller Ren, Tao (1); Jing, Yuan-Wei (1) 2007, 28 (1):  14-18.  DOI: - Abstract ( 213 )   HTML   PDF (278KB) ( 629 )   An intelligent PID controller is designed to adjust ABR traffic rate on-line in ATM network for the congestion of high-speed communication networks with a Smith predictor introduced in to avoid the adverse effect of roundtrip propagation delay on control. The improved PSO algorithm is introduced in tuning the parameters of PID controller. The controller designed is independent of the mathematic model of networks, thus getting rid of the adverse effects of such uncertainties as the number of users, ABR bandwidth and propagation delays on network performance and ensuring the fair distribution of bandwidth and full utilization of links. Simulation results show that the control system is stable and robust with QoS guaranteed. References | Related Articles | Metrics

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Heuristic algorithm for assignment reduction in incomplete information systems Gong, Jun (1); Tang, Jia-Fu (1) 2007, 28 (1):  19-22.  DOI: - Abstract ( 230 )   HTML   PDF (155KB) ( 554 )   Studying the attribute reduction in incomplete information systems, a GA-based algorithm is proposed to reduce assignment with the compatibility relation taken into account. The one-dimensional binary code is used to encode the algorithm because it is suitable to express genetic operators. Penalty function is introduced in the adaptive value function to speed up the convergence of the algorithm and ensure that the assignment reduction includes fewer attributes with stronger support. In addition, the single-point crossing is used as the rule with a given MaxGen iterative solution taken as termination criterion, thus providing a good searching result. An exemplifying analysis shows that the algorithm proposed is quick and effective in solving the problems of reducing knowledge. References | Related Articles | Metrics

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Model and algorithm of promotional pricing for seasonal commodities Wang, Hong-Da (1); Hao, Yi-Ge (2); Wang, Ding-Wei (1) 2007, 28 (1):  23-25.  DOI: - Abstract ( 351 )   HTML   PDF (585KB) ( 1681 )   The promotional pricing of seasonal commodities is studied taking account of their sales characteristics, discount rates, inventories, cyclical slump, real price, and so on. A dynamic pricing model is thus developed to minimize the loss of profit on a restricted condition that the volume of goods is needed to sell off. By the genetic algorithm and particle swarm, a pricing is given with optimal cost. The effect of pricing on loss of profit is analyzed through a simulation so as to provide an important reference for promotional decision-making in large/middle-scale companies. References | Related Articles | Metrics

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Design and implementation of an ontology-based medical resource database Zhu, Xin-Hua (1); Zhao, Da-Zhe (1); Yu, Ya-Xin (2); Liu, Ji-Ren (1) 2007, 28 (1):  26-30.  DOI: - Abstract ( 231 )   HTML   PDF (1064KB) ( 667 )   A high-performance Medical Resource Database System (MRDS) is described. Based on ontology, the system implements the unification of vocabularies in the domain of medical image and makes up for the semantic gaps between original data and the information inquired out by customers, medical textual information and image information and the resource database system and other systems. By semantic inference, inquiring navigation and processing the correlation feedback information inquired out, the system can understands the intention of customer better. The efficiency of inquiry is thus improved by means of paralleled computing. Experiment results showed that the system is able to unify the high efficiency, high recall ratio and high precision ratio into one. References | Related Articles | Metrics

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Computer aided diagnosis on hepatocirrhosis degree based on MRI Jiang, Hui-Yan (1); Zhao, Yue (2); Yang, Xin-Feng (1) 2007, 28 (1):  31-34.  DOI: - Abstract ( 264 )   HTML   PDF (288KB) ( 975 )   A new computer aided diagnosis (CAD) method for hepatocirrhosis is proposed, based on the recognition of characteristics of liver texture and shape. In the method, the liver region is segmented from the abdominal MRI-based image through image segmentation technique, and the characteristics of liver texture and shape are extracted from liver region. Then, the degree of liver fibrosis is calculated according to its texture and the improved BP neural network by conjugate gradient algorithm, and the passivation of left liver leaf is calculated according to its shape characteristics. Finally, the hepatocirrhosis is diagnosed taking the degrees of liver fibrosis and passivation as criteria. The method has been applied to the practical abdominal MRI, and showed higher accuracy in the diagnosis of hepatocirrhosis than single neural network. References | Related Articles | Metrics

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Early detection algorithm based on instant arriving mass data in SMS system Zhao, Hai (1); Liu, Zhi (2); Cheng, Ya-Qiong (2); Zhao, Ming (1) 2007, 28 (1):  35-39.  DOI: - Abstract ( 264 )   HTML   PDF (271KB) ( 511 )   In the short message service system (SMSS), some specific applications request lower loss rate in SMSS. When the instant arriving mass data (IAMD) comes along the queue length may overrun the buffer's maximum limit in the system so as to exceed the required loss rate of data. Therefore, an algorithm is proposed to reduce the queue length in the system by way of lengthening the latency for part of users to reduce the average latency for all the system users. Giving consideration to both time delay and loss rate of SMSS, the algorithm schedules the queue length for users in accordance to their different service times through checking the queue length in SMSS and estimating the service times for users. Thus, it will not only achieve the goal to control the queue length but also make users avoid too long latency when the queue length is limited in SMSS. References | Related Articles | Metrics

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Design of MATLAB simulation tool box for rough set data analysis system Zhang, Xue-Feng (1); Zhang, Qing-Ling (1) 2007, 28 (1):  40-43.  DOI: - Abstract ( 1226 )   HTML   PDF (295KB) ( 2921 )   The two kernel concepts, indiscernibility relation and relative positive region, are focused on. An algorithm is proposed to analyze the rough set data analysis system, according to the mutual dependency between different kinds of knowledge. The numbers of reduced attributes are compared to pick out a reduction result involving the minimum number of attributes. Taking the advantage of MATLAB in dealing with set functions, the program realizations of many algorithms are given to solve relative core, upper approximation, lower approximation, equivalence relation, relative significance level, relative reduction of attributes, relative reduction of domain and minimal decision rules, thus designing the MATLAB simulation tool. By way of graphical user interface (GUI), the favorable main interface of man-machine interaction system is designed. An example resulting from running is given, which shows the practical significance to the applications of rough set theory. References | Related Articles | Metrics

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On the WCSW: Website classification system wrapper Gao, Ke-Ning (1); Wang, Bo (1); Zhang, Bin (1); You, Zhen (1) 2007, 28 (1):  44-48.  DOI: - Abstract ( 197 )   HTML   PDF (1205KB) ( 588 )   In a website, various information is organized by its own navigation system, which involves the semantic characteristics of classification. In order to fulfill effective extraction of Web information, the WCSW (website classification system wrapper) based on HTML page blocking algorithm is proposed aiming at the classification system of websites. WCSW deals with navigation information blocks involving semantic classification in accordance to extraction rules, which the whole website as an object based on the blocking algorithm and analysis of semantic characteristics, the experimental result shows high-accuracy level classification in extracted websites with good practicability. References | Related Articles | Metrics

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NAT traversal strategy in DHT network Geng, Fu-Quan (1); Chen, Hao (1); Fang, Zhong-Min (1); Zhao, Lin-Liang (1) 2007, 28 (1):  49-52.  DOI: - Abstract ( 525 )   HTML   PDF (372KB) ( 1730 )   To solve the existing problems such as the poor expandability during NAT traversal and nonstandard protocol stacks, a new strategy using TCP called NatTT is proposed. With the services provided by the agent sever on the Internet, a routeway of TCP between the initial node and the receival node is thus available. Its effectiveness can be seen from test results. References | Related Articles | Metrics

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Effect of pre-aging on microstructure and properties of high-strength 2A97 Al-Cu-Li-X alloys Yuan, Zhi-Shan (1); Lu, Zheng (2); Dai, Sheng-Long (2); Liu, Chang-Sheng (1) 2007, 28 (1):  53-56.  DOI: - Abstract ( 214 )   HTML   PDF (553KB) ( 579 )   The high-strength 2A97 Al-Cu-Li-X alloys were investigated for the pre-aging effect on their mechanical properties and microstructures by means of tensile test, TEM and SEM. The results showed that the double-aging effect can enhance the alloys' plasticity due to pre-aging after quenching and quenching distortion, with the strength slightly lowers. The dislocation loops due to pre-aging after quenching distortion and the dislocation brought about by the distortion have the same effect, i.e. increasing the amount of T1(Al2CuLi) phases in matrix to distribute them more evenly. The polyphase microstructure consisting of T1, δ′ and θ′ was found due to double-aging after quenching distortion, with the size of T1 precipitates on grain boundary decrease due to pre-aging. Dislocation loops and vacancy clusters caused by pre-aging may nucleate δ′ and T1 in matrix with limited amount after quenching, and the pre-aging effect accelerates the formation of clusters of solute atoms, and increases the amount of nucleated δ′(Al3Li)/θ″ (Al2Cu) precipitates and make their sizes stable. After quenching the polyphase microstructure consisting of T1, δ′ and θ′/θ″ due to double-aging was found, where the amount of precipitates T1 on grain boundary decreases with δ′-free precipitation zones on the grain boundary narrowed clearly. References | Related Articles | Metrics

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On the soft-sensing system for workpiece's microstructure and mechanical properties during hot rolling He, Chun-Yu (1); Zhao, Xian-Ming (1); Wu, Di (1); Xu, Yun-Bo (1) 2007, 28 (1):  63-67.  DOI: - Abstract ( 219 )   HTML   PDF (257KB) ( 519 )   Discusses the architecture and functions required by the soft-sensing system for workpiece's microstructure and mechanical properties during hot rolling, especially the choice of auxiliary variables and the way to preprocess data both are integral to the soft-sensing system. Based on the mechanism model and artificial neural network (ANN), the architecture of the soft-sensing system is proposed via the technological mechanism analysis of hot rolling and system control requirements in site. The ANN input variables consist of the microstructure calculated by mechanism model and chemical composition of workpiece during rolling, thus normalizing the ANN architecture. During the application of the soft-sensing system, the short/long-term self-learning through correction model is used to meet the requirement of measuring accuracy for online detection. References | Related Articles | Metrics

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Developing mathematical model for relative thickness of oil film in support roll bearing of plate mill Zhang, Qi-Sheng (1); Hu, Xian-Lei (1); Zhao, Zhong (1); Wang, Guo-Dong (1) 2007, 28 (1):  68-71.  DOI: - Abstract ( 247 )   HTML   PDF (172KB) ( 499 )   The influence of oil film thickness variation on workpiece gauge control in rolling process is analyzed. Based on the Reynolds' formula of oil film thickness by virtue of roll zeroing to calculate stand spring, the relative thickness of oil film is calculated, with the measured values obtained from data acquisition done on some plate mills. Neglecting the effect of stand spring and making curvilinear translation, the oil film thickness variation curve is given as a result by which the model structure and relevant parameters of oil film thickness can be easily determined. The workpiece gauge control precision at both acceleration and deceleration stages can be improved effectively by this model. References | Related Articles | Metrics

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Orthogonal experiment of effects of Mn content and processing parameters on mechanical properties of low-carbon steel Li, Long (1); Ding, Hua (1); Du, Lin-Xiu (2); Song, Hong-Mei (3) 2007, 28 (1):  72-75.  DOI: - Abstract ( 276 )   HTML   PDF (1104KB) ( 707 )   Based on orthogonal experiment, the effects of Mn content, finish rolling temperature (FRT) and coiling temperature (CT) on mechanical properties of low-carbon steel were investigated by TMCP (thermo-mechanical control processing), and the mechanical properties were examined by variance analysis. The results showed that Mn content affects obviously the strength and plasticity, while CT affects significantly the yield strength which can exceed 400 MPa with other mechanical properties also improved well by readjusting FRT and CT if the Mn content in tested steel is 1.22% as mass fraction. References | Related Articles | Metrics

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Microstructure and mechanical properties of barium treated steels Li, Yang (1); Jiang, Zhou-Hua (1); Liu, Yang (1) 2007, 28 (1):  76-79.  DOI: - Abstract ( 215 )   HTML   PDF (488KB) ( 786 )   The 304 L stainless steel and 70 steel were treated by Si-Ca and Si-Ca-Ba alloys in laboratory and industrial test. The results of OM/SEM observations and tests for mechanical properties showed that the as-cast structure of the stainless steel treated by Si-Ca-Ba alloy is refined remarkably, and the lamellar thickness of pearlitic structure in 70 steel decreases with the pearlitic morphology showing clustering distribution because barium can change the surface energy of grains as a strong surface active element. Only a few bit of barium is found in steel and the enrichment of barium-bearing precipitated phase mostly lies on the grain boundary and phase boundary, thus improving the lattice misfit and preventing the movement of grain boundary and dislocation during heat-treatment and deformation. Therefore, the strength and toughness of barium-treated steels can be improved by the effects of intercrystalline strengthening and nail-prick dislocation. References | Related Articles | Metrics

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Study on copper pollution of soil in site area of a smeltery in Liaoning Yang, Hong-Ying (1); Zhu, Chang-Liang (1); Wang, Da-Wen (1); Jiang, Huan-Jie (1) 2007, 28 (1):  80-82.  DOI: - Abstract ( 282 )   HTML   PDF (166KB) ( 592 )   The copper content determined in soil and the morphological distribution of copper in the site area of a smeltery in Liaoning were studied. The results showed that in the Zn-smelting area the total Cu content in soil is 14, 37 and 49 times as high as the corresponding correlation value, provincial background value (of soil elements) and national background value, respectively; whereas in the Cu-smelting area the total Cu content in soil is 221, 575 and 748 times, respectively. So serious the Cu-pollution of soil is in the Cu-smelting area. It was found that Cu is mainly in residue form that is relatively stable, and its content is 63.4% and 38.5% in Cu-smelting and Zn-smelting areas, respectively. The copper content in soluble and exchangeable forms is few, and the total Cu content in such two forms is not over 1% in Cu/Zn-smelting areas. The Cu content in carbonate and organic forms is 55.6% and 33.7%, respectively, as found in Cu-smelting and Zn-smelting areas. References | Related Articles | Metrics

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Effects of para-phthalic sodium on sedimentation of red mud Lu, Zi-Jian (1); Bi, Shi-Wen (1); Xie, Yan-Li (1) 2007, 28 (1):  83-86.  DOI: - Abstract ( 267 )   HTML   PDF (209KB) ( 506 )   The effects of para-phthalic sodium, an organic compound in bauxite, on the sedimentation of red mud was studied, as well as the effects of different concentration of the compound on sedimenting rate, content of overflowing plankton and the ratio of liquid to solid compressed by bottom flow. One of some flocculants was added to eliminate the adverse effect of para-phthalic sodium, and the conditions available to add the flocculant were also studied. The results showed that the concentrations of para-phthalic sodium and flocculant both have important effects on the sedimenting rate of red mud, content of overflowing plankton and the ratio of liquid to solid compressed by bottom flow. Among the 4 flocculants the A-600 is the best one to eliminate the adverse effect of para-phthalic sodium on the sedimenting rate of red mud. If the concentration of para-phthalic sodium is lower than 3.58 g/L, any of the 4 flocculants can eliminate the adverse effect on the compressed liquid/solid ratio of red mud. References | Related Articles | Metrics

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Decomposition behavior of TiH2 and its application to fabricating aluminum foam Luo, Hong-Jie (1); Ji, Hai-Bin (1); Yang, Guo-Jun (1); Yao, Guang-Chun (1) 2007, 28 (1):  87-90.  DOI: - Abstract ( 368 )   HTML   PDF (214KB) ( 2158 )   The decomposition curves of TiH2 were determined at different temperatures, and how to decompose TiH2 was studied thermodynamically and kinetically. The way to use TiH2 as foaming agent to prepare aluminum foam was also discussed. The results showed that the decomposition rate of TiH2 increases with increasing temperature, and the decomposition process of TiH2 can be divided into three phases in a certain temperature range. In the range from 620°C to 680°C, the decomposition of TiH2 is violent for 10 min after starting, then the decomposing speed becomes slow during the next 10 min and the decomposition tends to stagnate after 20 min. In the range from 700°C to 720°C, the decomposing speed of TiH2 becomes very rapid for 6 min after starting, then decelerates during the next 4 min and stagnates later. References | Related Articles | Metrics

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Stiffness analysis and stiffness mapping of 3-RRR planar parallel mechanism based on CCT stiffness matrix Li, Shu-Jun (1); Gosselin, Clement (2) 2007, 28 (1):  91-94.  DOI: - Abstract ( 332 )   HTML   PDF (252KB) ( 627 )   The analytical stiffness equations of the part concerning joint stiffness and configuration and the uncompleted analytical stiffness equations of the part affected by external forces of 3-RRR planar parallel mechanism were all deduced, based on the conservative congruence transformation (CCT) stiffness matrix. The method of stiffness mappings was given, and the maps of the mechanism were presented to illustrate the properties of the stiffness of the mechanism. The stiffness characteristics of the mechanism were analyzed and discussed. It was revealed that the stiffness of the mechanism is configuration dependent and proportional to the actuating forces and joint stiffness. The stiffness becomes higher towards the boundaries of working space and vise versa, which forms a stronger stiffness 'ring' area near the boundaries, and a weaker stiffness 'zone' near the center of working space. References | Related Articles | Metrics

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Calculation of moving load on vehicle suspension when traveling on irregular road Wang, Tie (1); Ba, De-Chun (1); Wang, Qing (1); Ru, Hong-Qiang (2) 2007, 28 (1):  95-98.  DOI: - Abstract ( 294 )   HTML   PDF (1583KB) ( 576 )   A differential equation is derived for the vibration of vehicle's suspension system involving damping. Then, the transfer function is solved analytically through the solution to linear equation set with undetermined coefficients after Laplace transform, and the amplitude is solved by way of inverse Laplace transform. After an in-depth discussion on the Laplace transform and analytic solution as above, it is found that the transform is selective so that another analytic solution is available, which will be easier to express and analyze. Regarding the road pavement spectrum as the superposition of lots of sine functions and assuming that the vehicle is traveling steadily, an effective and simple analytic expression of amplitude is given based on the linear system additivity for outputs, thus avoiding the trouble with a series of solutions. In this way, the moving load on active suspension is given numerically, and the algorithm has been implemented with VB programming. The software developed therefore provides a preparation for the dynamic reliability design/analysis of suspension. References | Related Articles | Metrics

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Complexion-based algorithm for driver's face locating and tracking Yang, Ying (1); Yang, Jia (2); Sheng, Jing (1) 2007, 28 (1):  99-102.  DOI: - Abstract ( 278 )   HTML   PDF (307KB) ( 1024 )   A 2-dimensional mathematical model of Gause distribution was developed on the basis of human face complexion to obtain driver's face images using CCD camera and by the clustering analysis in chrominance space. It selects chrominance space as the statistical distribution of complexion and segments face image by maximum intercluster variance threshold to get horizontal and vertical projection of histograms of gradation of face image, thus locating the face. Kalman filter is used to track driver's face by predicting the location of image in next frame in accordance to the face image of driver in present frame and locating it precisely through local search. The experiment results showed that the algorithm to locate and track driver's face on the basis of complexion has high reliability, dynamically locating ability and adaptability to driver's posture. References | Related Articles | Metrics

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Research on product configuration framework based on distributed constraint satisfaction Shao, Wei-Ping (1); Liu, Yong-Xian (1); Hao, Yong-Ping (2); Zeng, Peng-Fei (2) 2007, 28 (1):  103-106.  DOI: - Abstract ( 253 )   HTML   PDF (123KB) ( 645 )   The problem of product configuration through Internet is studied considering it in the abstract, i.e. a constraint satisfaction problem. To share and express semantically the product configuration knowledge, a constraint network construction model is developed for product configuration through the object-oriented ontology, then the model is transformed into a distributed constraint satisfaction problem (DCSP) model for solution. Thus, it can represent the construction of parts of a product and relevant design knowledge exactly and completely. In addition, an asynchronous weak-commitment backtrack algorithm is developed to solve DCSP effectively and precisely. An example is given showing the application of the model in the design process of constructional configuration. References | Related Articles | Metrics

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Study on industrial wastewater treatment by way of electrolytic anode catalysis Zhang, Yi-Chen (1); Yan, Yun-Hui (1); Zuo, Ji-Cheng (2); Qian, Jiong (1) 2007, 28 (1):  107-110.  DOI: - Abstract ( 267 )   HTML   PDF (103KB) ( 831 )   The industrial wastewater containing high-concentration chlorophenol was tested and studied as an instance to make sure of the feasibility and effect of treating wastewater containing high-concentration organic compounds by way of electrolytic anode catalysis. A test was carried out in a reaction tank under 8 V and 45 mA/cm, where the values of COD in the simulated and washing wastewater containing high-concentration chlorophenol were 1388, 2343 and 1685 mg/L and the wastewater was treated for 2 hr and, as a result, 68% and 59% were removed, respectively. The results showed that the electrolytic anode catalysis is effectively feasible to the treatment of industrial wastewater containing high-concentration organic compounds, and it is technologically simple in operation and available to automatic control. It will have good prospects in iron and steel industry for water washing. References | Related Articles | Metrics

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Cut-and-sew algorithm: A new multi-contour reconstruction algorithm Ma, Hong-Bin (1); Guo, Jia-Teng (1) 2007, 28 (1):  111-114.  DOI: - Abstract ( 292 )   HTML   PDF (970KB) ( 840 )   Based on the reviews of current multi-contour reconstruction algorithms, a new algorithm named cut-and-sew (CS) is presented, in which a pair of control points is introduced as incision to cut and spread out a pair of contour lines to form two parallel line segments, after the coordinate transform of contour vertices and making one contour line corresponding to the other one in the same pair. Seeking for the corresponding relation between contour line vertices, the 3D shape's facial triangular pieces which conformed to Delaunay principle are generated, thus solving the reconstruction problem of two adjacent contour lines which are much different in shape and number of polygon vertices. The algorithm is proved efficient in the application for 3D geological modeling based on sections and inspirable to resolve other similar problems. References | Related Articles | Metrics

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Discussion on valuation of movement probability during ore-drawing computer-simulated Liu, Xiao-Bo (1); Li, Qi-Xuan (1); Sun, Huo-Ran (1); Li, Yuan-Hui (1) 2007, 28 (1):  115-117.  DOI: - Abstract ( 266 )   HTML   PDF (239KB) ( 522 )   Valuation of movement probability has remained difficult to solve up to now without appropriate solution given to it. Today the movement probability used in ore-drawing simulation is still with traditional valuation all through, but it is unadaptable to mining simulations nowadays. So, after the SLS ore-drawing tests carried out for many times, a discussion was made on the movement probability problem and some views were put forward, i.e. assigning different values to k during ore-drawing simulation so as to get different recovery indices. The different ore loosennesses are thus reflected to enable the simulation results to be closer to actual condition and at the same time, to simplify the valuation process of the nine-block probability. References | Related Articles | Metrics

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Inerting design and its application in pulverized coal drying process Zhong, Sheng-Jun (1); Radandt, Siegfried (2); Li, Gang (1); Shi, Jian-Ye (2) 2007, 28 (1):  118-121.  DOI: - Abstract ( 369 )   HTML   PDF (225KB) ( 1349 )   Reasonable inerting design can guarantee the safety of a process to treat combustible materials and save running cost. The measurement and test apparatus of limiting oxygen concentration (LOC) of combustible dusts were introduced with the LOC of some conventional combustible dusts given. Assuming that the gas is mixed homogeneously, the calculation methods of inerting times using pressure-swing inerting and vacuum-swing inerting, and the inerting time using flow-through inerting were deduced. An empirical formula was given for determining the minimum inert gas flow rate. An example of inerting design was given for a pulverized coal drying process, where the inert gas flow rate can be estimated by recycled air flow rate and air leaking rate. When shut down for a short time, a lower inert gas flow rate (1 or 2 equipment volumes per hour) can be used to maintain inert atmosphere. References | Related Articles | Metrics

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Dynamic strength failure of Schwedler latticed shells Yang, Yang (1); Zhi, Xu-Dong (2); Fan, Feng (2); Shen, Shi-Zhao (2) 2007, 28 (1):  125-128.  DOI: - Abstract ( 211 )   HTML   PDF (184KB) ( 815 )   Failure mechanism of the single-layer Schwedler latticed shells under severe earthquake actions was studied. The imperfect model of a 40 m-span Schwedler latticed shells was developed through a structural analysis of dynamic whole-course. Dynamic performance and failure mode of the shell were examined. The parametrical effects of the shell with initial imperfection were discussed to analyze how the three parameters affect the shell's dynamic performance, i.e. earthquake, section of members and roof loading. The dynamic failure mechanism and mode of such a shell structure were studied under different conditions, and the results were compared to other spherical latticed shells. The effectiveness of the suggested theoretical procedure was verified. References | Related Articles | Metrics

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Consistency analysis of two-tuple linguistic judgement matrix Jiang, Yan-Ping (1); Xing, Yan-Nan (1) 2007, 28 (1):  129-132.  DOI: - Abstract ( 274 )   HTML   PDF (159KB) ( 800 )   The two-tuple fuzzy linguistic representation model is a new approach to linguistic information aggregating, which make the aggregating result more precise and the language operation process easier and can avoid losing or distorting some of the original preference information in the process of aggregating linguistic information. The consistency of two-tuple linguistic judgement matrix is studied. Describing the definition of two-tuple, the rules to compare two different two-tuples are given. Several judgement approaches to the additivity consistency and satisfaction consistency of the two-tuple linguistic judgement matrix are introduced according to their concepts. Furthermore, the relationship between additivity and satisfaction consistencies is analyzed. An example is given to illustrate the use of the proposed approaches. References | Related Articles | Metrics

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Study on externality problem in principal-agent relational hierarchy Wang, Li-Na (1) 2007, 28 (1):  133-136.  DOI: - Abstract ( 233 )   HTML   PDF (162KB) ( 581 )   A three-tier principal-agent relational hierarchy is built within the authority concerned, supervisor and the enterprise discharging pollutants, i.e. within principal, agent and the third party. To solve the problem of principal-agent relation in pollutant discharging under the supervision of authority during the control of externality, a model is developed. In it, authority as principal who judges that enterprise is allowed to or not to collude with supervisor in according to the information provided by supervisor for pollutant discharge whether supervisor is integrity or not with relevant cost also calculated. Thus, an optimal range is available to authority for whether collusion between supervisor and enterprise is allowed or not, and simulation computation shows correspondingly conclusion. References | Related Articles | Metrics

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LMI-based robust optimization model of loan portfolio Gao, Ying (1); Huang, Xiao-Yuan (1); Li, Yi-Ou (2) 2007, 28 (1):  137-140.  DOI: - Abstract ( 259 )   HTML   PDF (964KB) ( 804 )   Linear matrix inequality (LMI) is used to study the robust optimization for commercial banks' loan portfolio. Based on Markowitz theory of mean-variance, a robust optimization model is developed for loan portfolio, and the uncertainty of prospectful return on loans is described by several expected return vectors and covariance matrices, to give a LMI solution to the model. A numerical simulation proves the validity of the model. Because in the model the uncertainty of prospectful return on loans has been involved, the result is highly reliable and robust to reduce the credit risk. So, the model may provide a reference for commercial banks to make decision on loans. References | Related Articles | Metrics

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Semi-parameter approach based on EGARCH-VaR model and empirical research Jin, Xiu (1); Xu, Hong-Yu (1) 2007, 28 (1):  141-144.  DOI: - Abstract ( 261 )   HTML   PDF (179KB) ( 1187 )   In view of the peaked and fat-tailed characteristics of financial return data distribution and its effect of clustering fluctuation and especially the 'leverage effect' of fluctuation on VaR (value at risk) estimates and some efficiencies when estimating VaR with various assumptions of return data distribution, a semi-parameter approach based on EGARCH-VaR model is developed. This model is then compared with the approach based on to measuring VaR on the basis of GARCH model which is assumed to be normal/t distribution. An empirical analysis in combination with posterior testing is done on Chinese stock market risk, which shows that during VaR measuring the semi-parameter approach is superior to the approach based on GARCH model which is assumed normal/t distribution. References | Related Articles | Metrics

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Post-buckling and carrying capacity of stiffened composite panels under axial compression/shear Liu, Jun (1); Huang, Bao-Zong (1) 2007, 28 (1):  149-152.  DOI: - Abstract ( 245 )   HTML   PDF (372KB) ( 481 )   The post-buckling and carrying capacity of thin-walled box-like structures under bending and twisting was predicted by the finite element analysis of stiffened composite panels. Based on a revised first-order shear theory, the panels were considered as Mindlin plates supported simply along four edges, which remained straight during deformation. The arc-length method and branch-switching technique with asymptotic analysis were applied to postbuckling path tracking. Three states of progressive failure were defined and the postbuckling and carrying capacity of stiffened panels were determined considering the influence of lamina failure on stiffness in accordance to Hoffman criterion. The numerical results showed that carrying capacity of the stiffened composite panels is considerably high in postbuckling states, and a good agreement was found between the prediction of carrying capacity and the experimental results of the composite box-like structures under bending and twisting. References | Related Articles | Metrics