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15 May 2008, Volume 29 Issue 5 Previous Issue    Next Issue
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Chaotifying continuous-time T-S model via Delta operator discretization Zhao, Yan (1); Zhang, Hua-Guang (1) 2008, 29 (5):  609-612.  DOI: - Abstract ( 215 )   HTML   PDF (1200KB) ( 490 )   A new approach was proposed to chaotify a class of continuous-time T-S fuzzy models. The delta operator is employed to discretize the continuous-time T-S fuzzy models globally so as to design a linear state feedback controller. Then, an operation of overflow nonlinear function is done for the whole closed-loop system to ensure the boundedness of the controlled system. It is proved that the system is thus chaotic in the sense of Devaney if the parameters of controller are chosen appropriately. The simulation results demonstrate the effectiveness of the proposed approach. References | Related Articles | Metrics

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Feedback control synchronization for a class of delayed chaotic systems with uncertain parameters Xie, Ying-Hui (1); Zhang, Hua-Guang (1); Wang, Fu-Shan (2) 2008, 29 (5):  613-616.  DOI: - Abstract ( 230 )   HTML   PDF (285KB) ( 530 )   A state feedback controller was designed by Lyapunov stability theory, and the sufficient conditions were given to the implementation of synchronization of two delayed chaotic systems via linear matrix inequality technique. Taking the delayed Chen chaotic systems and the delayed Lorenz chaotic systems as example and according to the given theorem, the linear matrix inequality is solved so as to make the two systems asymptotically synchronous. These examinations show that the designed controller is easy to implement in practice and the simulation results demonstrate the effectiveness of the presented method. References | Related Articles | Metrics

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Optimal robust H∞ control for networked control systems with saturated non-linear restriction Li, Jin-Na (1); Zhang, Qing-Ling (1); Han, Shi-Qian (2) 2008, 29 (5):  617-620.  DOI: - Abstract ( 206 )   HTML   PDF (1794KB) ( 607 )   Aiming at the networked control systems with possibly stochastic network-induced delay and data packet dropout, the stability of networked control systems is studied. Taking account of the uncertainties of the systems and external disturbance input, the saturated non-linear restriction is imposed on control input to develop a generalized model for the systems. By Lyapunov method, the sufficient conditions are given for the robust stability of networked control systems with saturated non-linear restriction. Then, the sufficient conditions are given for γ suboptimum and optimum robust H∞ control, thus obtaining the lainfw of optimal H∞ output feedback control. Simulation results showed that the stability criteria are feasible and the robust H∞ optimal control method with saturated non-linear restriction is valid. References | Related Articles | Metrics

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Interference suppression for L2 gain in nonlinear singularly perturbed systems Meng, Bo (1); Jing, Yuan-Wei (1); Liu, Xiao-Ping (1) 2008, 29 (5):  621-624+640.  DOI: - Abstract ( 241 )   HTML   PDF (261KB) ( 454 )   Dividing a nonlinear singularly perturbed system into the fast and slow subsystems and according to the assumption, a state feedback controller with asymptotic convergence is obtained for the fast subsystem. Then, based on Lyapunov function and the backstepping design technique, a state feedback controller for the slow subsystem is also constructed, which enables the closed-loop system to be internally stable for all bounded interference and satisfies the arbitrarily small bounded L2 gain from exogeneous interference input to its output. The strictly dissipative inequality for the whole system can be deduced through recursive method after getting that for the first subsystem. So, the design process of controller can be done without the solution to Hamilton-Jacobi equation. A simulation example shows the feasibility and effectiveness of the approach proposed. References | Related Articles | Metrics

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OUR-based identification of growth phases in batch fermentation Yang, Qiang-Da (1); Wang, Fu-Li (1); Chang, Yu-Qing (1); Zhang, Xuan (2) 2008, 29 (5):  625-628.  DOI: - Abstract ( 241 )   HTML   PDF (1134KB) ( 616 )   A simple identification based on the OUR (oxygen uptake rate) is proposed to rise above the difficulty of on-line classification of mycelia growth phases in aerobic fermentation process. The specific growth rate at a certain growth phase is pre-estimated using the on-line measurable OUR, then the on-line identification of growth phases is available to carry out in accordance to the pre-estimated value of specific growth rate. Such an identification is very easy to implement since the OUR can be obtained on-line. This method has been applied to Nosiheptide fermentation process, and the identification results are consistent with the actual process. It will not only deepen the understanding of the present situation of production, but also guide the timely implementation of various control schemes to improve the quality of products. References | Related Articles | Metrics

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License plate recognition method based on improved KPCA algorithm Wu, Cheng-Dong (1); Fan, Yu-Quan (1); Zhang, Yun-Zhou (1); Liu, Meng (1) 2008, 29 (5):  629-632.  DOI: - Abstract ( 272 )   HTML   PDF (310KB) ( 560 )   Analyzing the shortages of KPCA in feature extraction of license plate characters/figures, a new algorithm is proposed using multiple mean-vectors instead of original image information vectors to compute kernel matrix. Thus, the kernel matrix's dimensions can be reduced substantially with the image information of characters/figures kept up efficiently. Experimental results showed that the algorithm does not reduce the accuracy of recognition, during reducing greatly the number of dimensions of input data and the computing time can be shortened greatly, thus meeting satisfactorily the technological requirement for real-time recognition of vehicle license plates. The comparative test results revealed that this algorithm's performance indices are higher than both the conventional PCA and FLD algorithms. References | Related Articles | Metrics

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Modelling and optimization algorithm for solving vehicle routing problems of finished product re-depositing in steel plants Liu, Shi-Xin (1); Dong, Guo-Dong (1); Zhang, Tao (2) 2008, 29 (5):  633-636.  DOI: - Abstract ( 232 )   HTML   PDF (175KB) ( 703 )   The characteristics of finished product re-depositing problems in steel plants are analyzed. After transportation tasks being decomposed, the original problems are transferred to vehicle routing problems with constraints of latest visiting time and of number of vehicles which are simultaneously visiting the same warehouse. Consequently, a 0-1 program model is presented, and an iterated local search (ILS) algorithm is designed to solve the problems. The initial solution is generated by a greedy heuristic approach. Local search procedure is designed by combining four well-known local search operators. Perturbation operator adopts variable intension 2-opt* operator. The vehicle dispatching and vehicle route optimizing can simultaneously be done with the algorithm. The model and algorithm are tested by citing randomly generated problem instances. Computational results show that the model and algorithm are effective for solving this kind of problems. References | Related Articles | Metrics

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Edge detection algorithm based on multi-phase processing Pian, Zhao-Yu (1); Gao, Li-Qun (1); Guo, Li (1); Wang, Kun (1) 2008, 29 (5):  637-640.  DOI: - Abstract ( 179 )   HTML   PDF (1059KB) ( 527 )   A novel algorithm is presented for image edge detection and enhancement. During the edge detection phase, a new edge detection operator is employed to label exactly the edge because it can get rid of the conventional operators' miss-detection including the inflection and end points of edges and eliminate efficiently noise. During the edge enhancement phase, the Hopfield neural network is introduced to make up for missed edges and clear out false edges step by step via computing the energy function iteratively for network optimization. In this way the edge detection was done for the images of different types and the results are proved preferable to conventional detection procedure, thus verifying the feasibility of the algorithm. References | Related Articles | Metrics

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Edge detection method combing discrete information entropy with self-organizing map Wang, Kun (1); Gao, Li-Qun (1); Pian, Zhao-Yu (1); Guo, Li (1) 2008, 29 (5):  641-644.  DOI: - Abstract ( 238 )   HTML   PDF (1152KB) ( 580 )   An edge detection method is proposed combining image discrete information entropy with self-organizing map (SOM). A threshold is chosen from some different information entropies to segment the smooth region from the region where the gray level abruptly changes so as to reduce computation. Then, the gray level images are transformed into the ideal binary pattern of pixels. Six types of edge and six prototype vectors are defined, among them the latter are taken as inputs into SOM to classify the edge types and then obtain edge images from which the speckled edges are removed to acquire ideal edge images. Experimental results showed that the edge images gained by the method proposed are better than those by other edge detection methods. References | Related Articles | Metrics

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Geodesic active contour model aided with CV-GVF method Cui, Hua (1); Gao, Li-Qun (1) 2008, 29 (5):  645-648.  DOI: - Abstract ( 214 )   HTML   PDF (418KB) ( 531 )   Classical geodesic active contour is sensitive to initial location and noise. So, it often fails to converge to the true edge when the initial location is far from target edge or there is noise interference. The geodesic active contour aided with CV-GVF method is therefore proposed by way of combining the geodesic active contour with the coupling force field composed of gradient vector flow and CV method. Experimental results showed that it can converge exactly to the target edge in noise background from any initial location without special setting, i.e., high adaptability to initial location and background noise. References | Related Articles | Metrics

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Study on higher dimensional object function of PSO Zhao, Hai (1); Song, Chun-He (1); Qi, Tian-Yu (1); Gong, Hong-Yan (1) 2008, 29 (5):  649-652.  DOI: - Abstract ( 191 )   HTML   PDF (383KB) ( 552 )   A higher-dimensional-object-function particle swarm optimizer HDOF-PSO algorithm is proposed for the prematurities which are easy to take place when dealing with the higher-dimensional object function by BPSO(basical particle swarm optimizer) algorithm. The reason why HDOF-PSO is difficult to be deal with hasical PSO algorithm is analyzal. The confidence level and trial-and-error strategy are introduced into the algorithm to accelerate its convergence rate with the probability of success also introduced in to enable the adaptive correction available to the probability of mutation in searching process. The experimental results of a specific set of benchmerk functions showed that the HDOF-PSO algorithm has better convergence and higher dimensional object functions. References | Related Articles | Metrics

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Relationship between degree and core number of internet nodes at router level Zhang, Jun (1); Zhao, Hai (1); Zhou, Yan (1) 2008, 29 (5):  653-656.  DOI: - Abstract ( 303 )   HTML   PDF (389KB) ( 938 )   The Internet topology at router level is less focused on now. So, the massive data acquired in the period from January to December in 2006 and authorized by CAIDA Skitter project were used to analyze the searched topological data at CAIDA(cooperative association for Internet data analysis) router level, thus describing the characteristics of the distribution of the degrees of nodes at router level. Then, the core number for all nodes are computed, which embodies further the topological levels in Internet, thus describing the distribution of power laws of nodal cores especially the relationship between the degree and core number of nodes. It is revealed that the degree distribution relates to the power law for the nodes of low core number. References | Related Articles | Metrics

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PDT-based document fragmentation of XML streaming data Huo, Huan (1); Han, Dong-Hong (1); Hui, Xiao-Yun (1); Wang, Guo-Ren (1) 2008, 29 (5):  657-660+676.  DOI: - Abstract ( 210 )   HTML   PDF (413KB) ( 501 )   Unlike in conventional databases, queries on XML stream data are bounded by not only the memory capacity but also the real time processing. Based on the Hole-Filler model, a path frequency tree (PFT) is defined according to the statistic information on queries about XML to set out a sibling-based document fragmentation policy including corresponding algorithm. Then, an alternative membership-based document fragmentation policy and corresponding algorithm are proposed. Both algorithms can effectively enhance the utilization and cohesion of XML fragments. Testing results showed that the PFT-based document fragmentation algorithms perform well on query cost and other properties. References | Related Articles | Metrics

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Design and implementation of a time-driver-based buffer for real-time video stream Zhang, Yan-Feng (1); Wang, Cui-Rong (1); Zhao, Yu-Hui (1); Gao, Yuan (1) 2008, 29 (5):  661-664.  DOI: - Abstract ( 333 )   HTML   PDF (410KB) ( 1752 )   Reasonable buffer design plays a key role in video stream's decoding and rendering at the receiver side. According to the continuity of packed video data and best-effort character of Internet, a time-driver-based buffer is proposed. And a test method is also introduced to control the packet drop-out and disorder. The performance evaluation of the buffer is done by contrast with no buffer and buffers of different size. The result indicated that this buffer performed well in smoothing video display and could resolve packet drop-out and disorder problem. The proposed design has widely been applied to a certain large-scale client system receiving real-time video stream. References | Related Articles | Metrics

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On the algorithm of optimal transmitting rate available to be matched rapidly Zhao, Lin-Liang (1); Liao, Xian-Lin (1); Tian, Min (1); Qin, Yong (1) 2008, 29 (5):  665-668.  DOI: - Abstract ( 229 )   HTML   PDF (449KB) ( 642 )   To transmit the RTP-based audio/video stream as soon as possible so as to enable the sending terminal to get an optimal transmission rate is a problem to be solved urgently. An algorithm for optimal transmission rate that can be matched rapidly is therefore proposed for continuous medium stream. The algorithm improves the transmitting time for the next RTCP RR packet, which is required to compute in RTCP(real-time transport control protocol), thus making the sending terminal search quickly the current situation of network through RTCP information feedback and readjust timely its transmission rate to lower its influence on the stability of multimedia transmission. Simulation meets the require of real-time requirement. References | Related Articles | Metrics

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Performance of orthogonal space-time block codes over rayleigh fading channels Zhang, Zhen-Chuan (1); Liu, Yong-Zhi (1); Li, Zhe (1) 2008, 29 (5):  669-672.  DOI: - Abstract ( 258 )   HTML   PDF (288KB) ( 577 )   Based on the typical channel model of STBC in MIMO (multiple-in, multiple-out) wireless communication channels, a general expression of instantaneously received signal-noise ratio and anti-noise performance of OSTBC(orthogonal space-time block codes) over Rayleigh fading channel is deduced. A simulation was conducted using Simulink, as a result, the BER(bit-error rate) of several STBC systems modulated differently are comparatively analyzed. The results showed that when the number of receiving antennas is fixed, the performance of OSTBC is improved with the increasing number of transmitting antennas, and the more the number of transmitting antennas, the less the improvement. It is also revealed that the bandwidth utilization ratio is in complementary relation to anti-noise performance. References | Related Articles | Metrics

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Optimal pilot design in LS channel estimation for OFDM systems Wang, Han (1); Wang, Jin-Kuan (1) 2008, 29 (5):  673-676.  DOI: - Abstract ( 319 )   HTML   PDF (336KB) ( 1367 )   For the OFDM(orthogonal frequency division multiplexing) systems with guard band, the permissible biggest guard bandwidth is computed on the bases of the conventional UPPTS (uniformly placed pilot tones sequence) design and the premise that the MSE(mean square error) of the LS(least square) channel estimation must be minimum. Thus, the choosing range is given for the initial position of pilot tones sequence to enable the sequence to avoid guard band efficiently by way of adjusting the initial position. Simulation results showed that the system can give higher precision of channel estimation and lower BER(bit error rate) when the initial pilot tone falls into the choosing range mentioned above. The effectiveness and advantages of the presented algorithm are thus verified further. References | Related Articles | Metrics

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Estimation algorithm of two-dimensional direction of arrival based on L-shape array of distributed source Han, Ying-Hua (1); Wang, Jin-Kuan (1); Song, Xin (1) 2008, 29 (5):  677-680.  DOI: - Abstract ( 212 )   HTML   PDF (2057KB) ( 591 )   To estimate the 2D DOA(direction of arrival) of local scattered signals, a novel algorithm is suggested on the basis of L-shape array of coherently distributed source by way of reducing the steering vectors from coherently distributed source in form of integral to the Schur-Hadamard product of the steering vector from point source and real vector. Then, taking advantage of the array configuration to estimate the elevation angle, the azimuth angle is estimated using the second-order statistics based on Schur-Hadamard product. But the proposed second-order statistics is insensitive to white noise, so the SNR performance is improved. By the new algorithm the 2D-DOF joint operation is reduced to a two-step one-dimensional estimation problem, so as to reduce efficiently the computation. Simulation test shows its validity. References | Related Articles | Metrics

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Effect of carbon content on morphology of proeutectoid ferrite grains in Fe-C alloy in high magnetic field Wang, Shou-Jing (1); Song, Jian-Yu (1); Zhao, Xiang (1); Zuo, Liang (1) 2008, 29 (5):  681-684.  DOI: - Abstract ( 295 )   HTML   PDF (944KB) ( 538 )   The effect of carbon content on the morphology of proeutectoid ferrite grains in Fe-C alloys annealed in high magnetic field was investigated, especially in high-purity Fe-0.12C, Fe-0.36C, Fe-0.52C and Fe-0.76C alloys. The results showed that the grain size of the proeutectoid ferrite gradually decreases with increasing carbon content and the trend to elongating the grains in the magnetic field direction to form chain-like arrangement becomes weaker. This phenomenon is not only attributed to the different carbon contents of the Fe-C alloys, but also closely related to the formation process and evolution mechanism of the proeutectoid ferrite grains. Consequently, a magnetic dipole model is proposed applicable to the early stage of proeutectoid ferrite transformation in low carbon Fe-C alloys or in case the distance between proeutectoid ferrite nucleus is relatively long in the Fe-C alloys in which the carbon content approaches the eutectoid composition. References | Related Articles | Metrics

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Phase transformation behavior of low-carbon Si-Mn TRIP steel during continuous cooling Zhu, Li-Juan (1); Wu, Di (1); Zhao, Xian-Ming (1); Zhou, Xiao-Guang (1) 2008, 29 (5):  685-688.  DOI: - Abstract ( 314 )   HTML   PDF (1324KB) ( 581 )   The kinetics of work-hardened austenite transformation of TRIP(transformation induced plasticity) steel is different from the conventional C-Mn steel in their alloy contents, cooling rates and carbon contents in residual austenite, and all the differences should be emphasized for the TRIP steel. Based on the Avrami equation, the parameters of the kinetic model of phase transformation of hot-rolled Si-Mn TRIP steel were determined, and the influences of Si content, hot deformation and cooling rate on the phase transformation of hot deformed austenite were quantitatively investigated. The CCT curves predicted by the model showed that they are in good agreement with experimental ones. The calculation results show that the increase in either Si content or deformation benefits the ferrite transformation hence the carbon enrichment in residual austenite. References | Related Articles | Metrics

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Effect of cold-rolling cladding on microstructure and properties of composite aluminum alloy foil Zu, Guo-Yin (1); Li, Bing (1); Li, Hong (1); Yu, Jiu-Ming (1) 2008, 29 (5):  689-692.  DOI: - Abstract ( 275 )   HTML   PDF (359KB) ( 729 )   The cold-rolling cladding process of composite aluminum alloy foil for automobile heat exchanger was investigated, as well as the effects of percentage reduction of first pass, clad sheet thickness and final annealing schedule on the microstructure and properties of the foil. The results showed that bonding the clad sheets A4045 to the core material A3003 on both sides succeeds initially when the percentage reduction is 30%-50% of first pass during cold rolling, and the thickness of both the clad sheets of the composite foil are basically the same. The best sagging resistance is available when the percentage reduction of final pass is 25%-35%. The annealing temperature should be controlled in the range from 320 to 400°C before finish rolling, and the annealing time should control within 80 minutes when annealed at 400°C. References | Related Articles | Metrics

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Development of overlaying welding materials and process for long service life continuous casting rolls Sun, Da-Le (1); Li, Xiao-Bing (2); Yao, Li-Song (2); Liu, Cheng-Min (2) 2008, 29 (5):  693-696.  DOI: - Abstract ( 341 )   HTML   PDF (506KB) ( 1189 )   Introducing the process characteristics and failure types of continuous casting rolls for slab, the requirement for performance of continuous casting roll and current research on overlaying welding materials are described. A new overlaying welding rod for continuous casing rolls was then developed by adding some functional alloying elements into the 1Cr13NiMo series martensite corrosion-resistant steel as basic welding flux, as well as the sintered flux to match it. With the newly developed welding materials used, the structure, strength and thermal fatigue resistance of the weld zone are all better than those of imported rolls. How the different interlayer temperatures during overlaying welding and heat treatment temperature after welding affect the weld zone were both investigated, and the results showed that the most favorable structure and mechanical properties are available if both are chosen appropriately. The service life the continuous casting rolls thus welded is proved longer than imported ones. References | Related Articles | Metrics

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Melting characteristics of agglomerating phase in sinter Li, Guang-Sen (1); Jin, Ming-Fang (1); Jiang, Xin (1); Shen, Feng-Man (1) 2008, 29 (5):  697-700.  DOI: - Abstract ( 348 )   HTML   PDF (1313KB) ( 825 )   The melting characteristics of agglomerating ferrite phase in high-basicity sinter were investigated and discussed to grasp the relationship between the melting temperature and the phase's composition by way of the experiments in which the mass fractions of nCaO:nFe2O3, w(MgO), w(SiO2) and w(Al2O3) in the agglomerating ferrite phase were all changed. The results indicated that melting temperature is the lowest with melting time the shortest if nCaO:nFe2O3=1:1, and the phase's melting temperature/time increases if adding MgO into the sinter. The melting temperature/time falls down to the minimum if the mass fraction of either w(SiO2) or w(Al2O3) is 3%. References | Related Articles | Metrics

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Study on temperature field in an intermittent reheating furnace Li, Bao-Kuan (1); Qi, Feng-Sheng (1); Wang, Fang (1); Gao, Tai-Yin (1) 2008, 29 (5):  701-704.  DOI: - Abstract ( 277 )   HTML   PDF (405KB) ( 584 )   To make sure that the billet/bloom temperature meet the rolling requirement so as to provide quality steel sections, the temperature distribution in reheating furnace is of crucial importance. With the intermittent reheating furnace using natural gas as fuel exemplified, the transient 3D distribution of temperature fields in the furnace and heated billet/bloom are analyzed introducing CFD(computational fluid dynamics), i.e., the software Fluent is used to simulate the temperature distribution in furnace under different operating conditions, thus providing theoretically a reference for improving the efficiency of reheating furnace. In the simulation the heat loss due to furnace door opening for billet/bloom discharging and charging is taken into account. The simulation results are available to optimize the operating parameters so as to improve the quality of finished paroducts. References | Related Articles | Metrics

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Ultrasonic preparation of ultrafine silica and analysis of influencing factors Shen, Xiao-Yi (1); Liu, Yan (1); Zhai, Yu-Chun (1); Gu, Hui-Min (1) 2008, 29 (5):  705-708.  DOI: - Abstract ( 303 )   HTML   PDF (373KB) ( 620 )   The ultrafine silica powder was prepared ultrasonically using sol-gel method in 2-propanol-H2O-NH3 system, where the ammonia acts as the catalyst during reaction. The ultrafine silica powder sample was characterized by SEM, XRD and IR, and the results indicated that the SiO2 particles thus prepared are amorphous in regularly spheric shape with uniform size and contain lots of hydroxides. The influences of ultrasonic power, reaction temperature, mole mixture ratio of reactants and concentration of ammonia solution on sample's morphology and particle size were studied through some single-factor experiments, and the results revealed that the ultrasonic power affects particle size greatest with the mole mixture ratio of reactants as the next. Besides them, the influence of the concentration of ammonia solution is also considerable. References | Related Articles | Metrics

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Synchronization/stability characteristic analysis based on hamilton principle for multi-machine vibration systems Zhang, Nan (1); Hou, Xiao-Lin (2); Wen, Bang-Chun (1) 2008, 29 (5):  709-713.  DOI: - Abstract ( 254 )   HTML   PDF (2282KB) ( 576 )   Based on the Hamilton principle, the synchronization/stability characteristic analysis for multi-machine vibration system is theoretically put forward. Then, based on the Lagrange theory and earlier works concerning synchronous stability for 6-DOF multi-machine vibration system, a dynamic model of 12-DOF multi-machine vibration system is developed first and, on the Hamilton principle, it provides the characteristic conditions for synchronous operation and especially the synchronously stable operation. Such a synchronization/stability theory is available to apply widely to segmental vibration screens of multi-machine and multi-screen systems. The analysis result indicated that a segmental vibrating screen system with 3-DOF inertial reversing rotation is available to work synchronously and stably if satisfying certain conditions, thus providing theoretically a reference for the design of those systems. References | Related Articles | Metrics

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Improved finite element model for dynamic simulation of cracked beam Wu, Ning-Xiang (1); Xie, Li-Yang (1); Wu, Ke-Qin (1); You, Mei-Yan (1) 2008, 29 (5):  714-717.  DOI: - Abstract ( 255 )   HTML   PDF (264KB) ( 959 )   Because of no definition given to the smeared crack model in crack influencing zone, a calculation method based on the principle of equivalence of strain energy is proposed to determine the crack element length, thus enabling the conventional rough modeling process to be more practical and finding out the dependence of crack depth on crack influencing zone. It is found that the crack influencing zone becomes maximum when the dimensionless crack depth is 0.4 which is 0.443 times as large as the beam height. A numerical example is given and shows that the simulation results by use of the improved model is basically in conformity to testing results. References | Related Articles | Metrics

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Research on 3D networked collaborative design based on multi-agent system Qu, Li-Gang (1); Wang, Wei (2); Gong, Ya-Dong (1); Wang, Wan-Shan (1) 2008, 29 (5):  718-721+729.  DOI: - Abstract ( 249 )   HTML   PDF (653KB) ( 542 )   An MAS-based functional and architectonic model of a collaborative 3D design system and a typically structural model of Agent were proposed according to the computer supported collaborative design (CSCD) which plays an important role in advanced manufacturing technology. The key technologies including project management, selection of collaborator in F-AHP algorithm and tasks' decomposition/assignment based on DSM method are all discussed, as well as the implementation of collaborative communication, interactive instrument and design tools. An archetypal system of collaborative 3D design is then built. The system has been experimentally implemented in an actual design process of a certain industrial product to verify its project-management-oriented function. References | Related Articles | Metrics

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Numerical simulation of back sublevel fill stoping with parallelogramic stope structure Zhang, Guo-Lian (1); Zhao, Xing-Dong (1); Yang, Yu-Jiang (1) 2008, 29 (5):  722-725.  DOI: - Abstract ( 294 )   HTML   PDF (966KB) ( 488 )   The current applications and problems of sublevel filling stoping in Laixin Iron Mine of Luzhong Metallurgic Group were discussed involving such factors as the natural roof caving characteristics of rock/ore at stopes, possible recovery ratio and blasting effect and avoidance of drift driving within fillers. A method of back sublevel filling stoping with parallelogramic stope structure is thus proposed, which is investigated numerical simulation using the 2D-σ software for finite element analysis. The results show that the tensile stress concentration and/or other high stress concentration in rock/ore will not occur in stoping process if applying the method proposed to mining, and the stress in surrounding rock is distributed uniformly along its periphery. And the plastic zone is not found in either wall on both sides of surrounding rock and roof except the filler bottom after stoping. The method is thus proved feasible to fragmentarily bulk ore body in Laixin Iron Mine. Analyzing comparatively the distributions of surrounding rock stress and plastic zones at different heights of sublevel with technological requirements taken into account, the sublevel height is determined to be 10 m. In view of the stoping effect on neighboring rooms, it is suggested that the strength of filler should be over 1 MPa. References | Related Articles | Metrics

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Bench blasting designed by fuzzy neural network Wang, De-Xuan (1); Zhang, Ji-Chun (2); Zhu, Yu (3); Liang, Li (1) 2008, 29 (5):  726-729.  DOI: - Abstract ( 235 )   HTML   PDF (217KB) ( 701 )   To improve the veracity of blasting parameter designing and computing, the method applying fuzzy neural network to selecting borehole pattern parameter is introduced in the design of bench blasting. Fuzzy neural network as the model of human brain is a new technology integrating both the superiorities of fuzzy inference system and neural network together. So, the application of fuzzy neural network model to intelligent design of bench blasting combines the advantages of computer with that of expertise to gain the experience/knowledge from what the experts did in actual blasting process in the past. Bench blasting can be well designed and carried out reliably so as to improve the production efficiency by use of the model that provides a reliable reference to productive blasting. References | Related Articles | Metrics

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On the adsorbent performance for phosphorus removal from substrate of constructed wetland Li, Xiao-Dong (1); Li, Hai-Bo (2); Ma, Zheng-Zheng (1); Sun, Tie-Heng (1) 2008, 29 (5):  730-733.  DOI: - Abstract ( 270 )   HTML   PDF (240KB) ( 716 )   The effects of sand, tapping slag and WGS(water granulated slag) used as adsorbents on phosphorus removal from the substrate of constructed wetland(CW) were investigated isothermally through adsorption tests, as well as their adsorbilities. The results showed that the isothermal adsorption process can be represented well by both the Freundlich and Langmuir equations. Theoretically the saturated adsorbilities for phosphorus removal of sand, tapping slag and WGS are 270, 12500 and 3333 mg·kg-1, respectively. After the substrate has been saturated through such adsorption, the results of desorption test of phosphorus showed that the desorbility of WGS is 0.68%, i.e. the lowest, while that of sand is the highest, i.e. 7.59%. As to the tapping slag, its adsorbility is the highest but its solution presents high pH value or high alkalinity and hence inadaptable to the growth of mire plants. As an industrial waste, WGS's adsorbility is about 12 times as high as sand and its desorbility is just 1/10 of sand, especially WGS has no obvious hazard to the growth of plants. So, comparatively, WGS has good prospects for phosphorus removal from CW. References | Related Articles | Metrics

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Analysis coupling fracture with damage for oblique cracks in brittle materials Sun, Ya-Zhen (1); Yu, Tian-Qing (1) 2008, 29 (5):  734-737.  DOI: - Abstract ( 210 )   HTML   PDF (391KB) ( 957 )   The oblique cracks due to unidirectional tension in brittle materials were analyzed coupling the Sidoroff damage model with fracture mechanics. Boundary equations between damage zone and fracture zone were derived to determine the radial sizes of initial damage and fracture zones due to oblique cracks. A new concept was proposed, i.e. the radial strain energy within the fracture zone near oblique crack tip. Then, a relevant criterion was set for crack propagation, i.e. the criterion for radial minimum strain energy(RMSE) within fracture zone. As a result, the crack orientation at fracture zone boundary and the coordinate of initial cracking point of different oblique cracks were both determined. References | Related Articles | Metrics

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Stress analysis of concrete under impact loading Zhao, Wen (1); Liang, Lei (1); Zhang, Feng-Chun (1); Li, Yi (1) 2008, 29 (5):  738-741.  DOI: - Abstract ( 289 )   HTML   PDF (296KB) ( 1340 )   The stability of a pass has great effect on the mine production, on which not only the static load but also impact load act. Among them the latter is the main cause of high rate of failure of the pass. To explore the effect of impact load on the pass, the contact elasticity analysis by Hertz is made to solve the stress in the concrete specimens of different sizes under steel ball impact, and the dynamic analysis software LS-DYNA3D is used to simulate numerically the impact process for the same stress. The two results are compared and reveal that the stress in specimens increases slowly with the increasing impact energy of steel ball especially the increasing size of specimens. It implies that the higher the plastic deformation energy, the more obvious the size effect, thus resulting in the fact that the specimen failure is due to the increase in the frequency of impact. References | Related Articles | Metrics

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Co-op advertising strategy of a two-stages supply chain in price-sensitive demand Zhong, Lei-Gang (1); Cui, Yang (1); Huang, Xiao-Yuan (1) 2008, 29 (5):  742-745.  DOI: - Abstract ( 199 )   HTML   PDF (320KB) ( 499 )   Studies the relationship between a manufacturer as the leader and retailers as followers. Recent market structure was explored and the results showed that the realization of retailing behavior is shifting from manufacturers to sellers. This new marketing trend is discussed in detail to explore that what is the optimum advertising effect and co-op strategy between manufacturers and sellers in Stackelberg/Nash equilibrium. The efficiency of co-op adverting is therefore found if a manufacturer and seller joint together to share the investment in logo/trademark and local and other cities' advertising expenses. An example is given to reveal what change the manufacturers shall take in advertising strategy with the change in marginal profit rates of both manufacturer and seller. References | Related Articles | Metrics

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Operating efficiency analysis of high-growth technological SMEs Jing, Hao (1); Zhao, Xi-Nan (1) 2008, 29 (5):  746-749.  DOI: - Abstract ( 227 )   HTML   PDF (176KB) ( 555 )   The high-speed and sound development of technological SMEs rely on high operating efficiency. Identifying the high-growth technological SMEs by GEP method, a comprehensive analysis is made to those SMEs' operating efficiency including technological efficiency and cross-efficiency, and the results reveal that the technological efficiency is often inconsistent with cross-efficiency. Based on technological efficiency and maverick index, the clustering analysis is made and the 2-year results is compared annually to identify the enterprises with high overall operating efficiency as the benchmark enterprises. The change in clustering results are further analyzed. References | Related Articles | Metrics

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Incentive and monitoring for R and D staff in software enterprises Wang, Yan-Mei (1); Zhao, Xi-Nan (1) 2008, 29 (5):  750-752+756.  DOI: - Abstract ( 234 )   HTML   PDF (244KB) ( 853 )   Analyzes the characteristics of software R and D to develop a principal-agent model for the project managers and R and D team members. The solution to the model offers the R and D staff the choice of equilibrium efforts and gives an optimal incentive coefficient to project managers under horizontal monitoring, and it in turn offers the optimal monitoring effort to project managers under vertical monitoring. The optimal incentive/monitoring mode for R and D staff is further discussed by way of comparing the equilibrium solution to the basis incentive model with that to either horizontal or vertical monitoring model. Then, the best behavior of both principal and agent under either horizontal or vertical monitoring and its influencing factors are analyzed in depth with some conclusions drawn. References | Related Articles | Metrics

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Risk prevention: Choice of corporation dynamic alliance partners Xu, Jian (1); Bu, Xiao-Ming (2); Wen, Xin (1); Zhao, Xi-Nan (1) 2008, 29 (5):  753-756.  DOI: - Abstract ( 185 )   HTML   PDF (280KB) ( 588 )   The choice of partners during organizing a dynamic alliance of corporations is so important that it will decide whether the alliance meets with success. Differing from what was emphasized in earlier works where the high risk due to improper choice of alliance partners and risk precontrol had not been taken into account, the principle and criterion of choice of alliance partners are put forward in a risk prevention perspective. In the assessment/choice process of alliance partners, a corporation's core competence, risk sustainability and project flexibility are all included. The procedure and practice of multi-stage choice of alliance partners are set out with a numerical example. References | Related Articles | Metrics

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Quenching behavior of high-temperature superconductor operating under conditions of GM refrigeration Bai, Zhi-Ming (1); Sun, Yu-Yan (1); Yang, Gang (1); Shan, Di (1) 2008, 29 (5):  757-760.  DOI: - Abstract ( 232 )   HTML   PDF (797KB) ( 547 )   The quenching behavior of high-temperature superconductor Bi2223/Ag strip cooled at 30-70K under conditions of GM refrigeration was investigated experimentally. A testing setup for quench propagation of superconductor was thus built up with the control procedure programmed by LabVIEW language for the testing system to measure the quench propagation velocities under different operating conditions. The results showed that the quench propagation velocities increase with temperature rise and increasing current, i.e. the higher the temperature and current, the lower the superconductive stability and the easier the formation of quench propagation. Such results are in conformity to that by theoretic analysis. References | Related Articles | Metrics