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15 April 2007, Volume 28 Issue 4 Previous Issue    Next Issue
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Research on link optimizing and delay-constrained multicast routing via GA Yue, Cheng-Jun (1); Jing, Yuan-Wei (1); Li, Qing-Kui (2) 2007, 28 (4):  457-460.  DOI: - Abstract ( 236 )   HTML   PDF (290KB) ( 565 )   Taking account of the bottleneck-path which results in the congestion of network and analyzing the reason of unbalanced load with the link cost redefined, a genetic algorithm (GA) is presented to solve the problem of multicast routing. The algorithm begins from a conversion of the weight of link cost with an initial solution set in terms of delay-satisfied multicast trees provided for GA, then the expensive tree links are substituted iteratively with the cheaper ones during the crossover operation so as to get the multicast tree satisfying delay constraint with lowest cost. Simulated results showed that the proposed algorithm is available to construct effectively and quickly, the multicast tree satisfying delay constraint and lowest link cost, with network load balance taken into account to pick out the cheaper idle route. References | Related Articles | Metrics

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Decentralized impulse control of large-scale interconnected uncertain descriptor system Ma, Yue-Chao (1); Zhang, Qing-Ling (1); Xu, Xiang-Kun (2) 2007, 28 (4):  461-464.  DOI: - Abstract ( 286 )   HTML   PDF (162KB) ( 550 )   The decentralized impulse control of a class of large-scale interconnected uncertain descriptor systems is studied by using Lyapunov method and matrix norm properties. With a kind of feedback controllers in decentralized state designed the norm bounds of system uncertainties are obtained to ensure the robust stabilizability. Meanwhile, the impulse control of a large-scale interconnected uncertain descriptor system and its every isolated subsystem is studied, thus giving the norm bounds of system uncertainties to ensure no impulse in closed-loop system. As a result, the simultaneous asymptotical stable norm bounds without impulse are obtained for the closed-loop system in the large-scale interconnected uncertain descriptor system and its every isolated subsystem. References | Related Articles | Metrics

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Observer-based optimal guaranteed cost control of singular time-delay systems with uncertainties Feng, Yi-Fu (1); Zhang, Qing-Ling (1); Yang, Fan (1) 2007, 28 (4):  465-468+476.  DOI: - Abstract ( 239 )   HTML   PDF (190KB) ( 624 )   The design of an observer-based optimal guaranteed cost controller for a class of singular systems with state-delay and parameter uncertainties was presented. The uncertainties are assumed to be time-varying and norm-bounded. The sufficient conditions enabling a singular system with observer-based guaranteed cost controller to stabilize its linear state feedback is obtained by using a new method in combination with the convex optimization theory. The obtained control law that the descriptor time-delay systems is robust stabilizable and the quadratic guaranteed cost function value is optimal in the sense of minimizing the upper bound of the cost function as proposed. It is also shown that these conditions are equivalent to the solvability of some linear matrix inequalities. A numerical example was provided to prove the validity of the proposed method. References | Related Articles | Metrics

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Robust H∞ control for discrete switched systems with time-varying delays Song, Zheng-Yi (1); Nie, Hong (1); Zhao, Jun (1) 2007, 28 (4):  469-472.  DOI: - Abstract ( 239 )   HTML   PDF (202KB) ( 478 )   The multiple Lyapunov function is used to study the robust H∞ control of a class of linear discrete switched systems with time-varying/delaying uncertainties. Assuming that the H∞ control cannot be implemented in each individual subsystem and based on switching state feedback control, a delay-dependent and LMI (linear matrix inequalities)-based sufficient condition is given for the system implementation of robust H∞ control. In addition, the designs of switching law and robust H∞ controller are given, with the relationship between time-delay bound and H∞ performance discussed. A simulation example is given to show the validity of the results. References | Related Articles | Metrics

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Algorithm based on wavelet lifting transform for extraction of multi-scale edge Ge, Wen (1); Gao, Li-Qun (1); Shi, Zhen-Gang (1) 2007, 28 (4):  473-476.  DOI: - Abstract ( 216 )   HTML   PDF (266KB) ( 1587 )   An algorithm based on wavelet lifting transform is proposed for improving multi-scale edge detection. It should be carried out the way the source image is decomposed by wavelet lifting transform so as to extract the edges of high-frequency and low-frequency sub-images separately. Then, the Canny operator is used for low-frequency information during edge detection, while the high-frequency component is detected after noise removal through multiplying the wavelet coefficients on adjacent scales. The final edge images are obtained through a fusion in accordance to certain rules. Experimental results showed that the algorithm is effective to extract image edges and has advantages of quick operation, efficient suppression of noise and high detection accuracy. References | Related Articles | Metrics

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Spatiotemporal algorithm for automatic video segmentation Sun, Hong-Xing (1); Zhao, Nan-Nan (2); Xu, Xin-He (1) 2007, 28 (4):  477-480.  DOI: - Abstract ( 238 )   HTML   PDF (442KB) ( 463 )   To implement the object-based video coding, a video sequence is needed to segment it into several individual objects. A spatiotemporal algorithm is therefore presented for automatic video segmentation. In the temporal state a preliminary segmentation is done through detecting the difference between two successive frames to locate the moving object in rough, while in the spatial state the predictable watershed algorithm is used to accelerate the conventional one and make the temporal segmentation result more exact. The two results in both temporal and spatial states are complementary to each other to benefit the automatic video segmentation. Furthermore, the whole segmentation process is performed on the images after wavelet transform to avoid oversegmenting. Experimental results showed that the proposed method provides not only the better segmentation quality but also the low computational cost, especially the more exact and practical semantic information. References | Related Articles | Metrics

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Adaptive synchronization for a class of delayed Ikeda chaotic systems Xie, Ying-Hui (1); Zhang, Hua-Guang (1) 2007, 28 (4):  481-484.  DOI: - Abstract ( 231 )   HTML   PDF (324KB) ( 498 )   The adaptive synchronization is discussed for a class of delayed Ikeda chaotic systems, where the construction and part of parameters of drive and response systems are different with the rest of parameters unknown. Based on Lyapunov stability theory and Barbalat lemma, an adaptive synchronization controller is designed with the adaptive law of parameters given. The designed controller is easy to implement in practice to enable two different delayed Ikeda chaotic systems to synchronize asymptotically with each other. The proposed method is applicable to not only the delayed Ikeda chaotic systems but also the bounded and continuously delayed chaotic systems in any state. Simulation results verified the effectiveness of the method. References | Related Articles | Metrics

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Robust governor for the hydroelectric unit based on state feedback H∞ control Luo, Nan-Hua (1); Wang, Wei (2); Yang, Xiao-Ju (3) 2007, 28 (4):  485-488.  DOI: - Abstract ( 219 )   HTML   PDF (297KB) ( 615 )   Considering the characteristics of an axial-flow Kaplan turbine, an approach is proposed to optimizing the control of Kaplan turbine-generator unit, which is derived from linear matrix inequalities and based on the state feedback H∞ control. Both the guide vane opening and blade opening of a hydropower generating unit can be separately regulated during disturbance according to the optimal regulation laws thus obtained to optimize the transient process of water flow. Simulation results showed that the proposed approach can obviously reduce the disturbance effect on the system and improve the robustness of the system. References | Related Articles | Metrics

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Optimal distribution of mobile nodes in wireless sensor network Zhang, Shi (1); Bao, Xi-Rong (1); Chen, Jian (1); Jia, Ying-Hua (2) 2007, 28 (4):  489-492.  DOI: - Abstract ( 371 )   HTML   PDF (263KB) ( 1250 )   The optimization of node distribution is studied to reduce the energy consumption and ensure the effective information acquisition in wireless sensor network. A precise mathematical definition is given to the control model covering a wireless sensor network. According to the mobility of sensor nodes, an optimized distribution algorithm based on genetic algorithm is proposed, which, as shown in the simulation results, can not only optimize the node distribution in target area but also reduce the network energy consumption and increase the whole coverage rate at a relatively low cost. References | Related Articles | Metrics

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Measurement of dust concentration in Hartmann Bomb Li, Xin-Guang (1); Dong, Hong-Guang (1); Radandt, S. (2) 2007, 28 (4):  493-496.  DOI: - Abstract ( 791 )   HTML   PDF (359KB) ( 713 )   The dust concentration and velocity of turbulence have significant effects on the level of explosion and measurement of the minimum ignition energy of dust clouds. The research conducted a measurement study on the dust concentration in a 1.2L Hartmann Bomb, analyzed the measurement data, and finally obtained the time-dependent curves of dust concentration at different heights in a 1.2L Hartmann Bomb. The dust concentration along heights in the Hartmann Bomb distributes ununiformly. For a given position height of the electrode in the Hartmann Bomb and the ignition delay time of 170 ms, when the calculated concentration is 500 g/m, the measured concentration equates approximately to the calculated concentration; when the calculated concentration is lower than 500 g/m3, the measured concentration is higher than the calculated concentration, and vice versa. The obtaining of the distribution of dust concentration along the heights in the Hartmann Bomb provides both the data for the comparison of the measurement and test of the minimum ignition energy at different equipment and the supporting evidences for the verification of the mathematical model of dust explosion. References | Related Articles | Metrics

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Hybrid intelligent preventive fault-tolerance QoS multicast routing scheme in NGI Wang, Xing-Wei (1); Cai, Shu-Xiang (1); Huang, Min (1) 2007, 28 (4):  497-500.  DOI: - Abstract ( 296 )   HTML   PDF (1108KB) ( 455 )   IP (Internet protocol)/DWDM (dense wavelength division multiplexing) optical Internet is one of the mainstream networking techniques as backbone for next generation Internet (NGI), and how to improve its fault tolerance capability and quality of service (QoS) multicast provision becomes critical. In this respect, the fault-tolerant QoS multicast routing is one of the effective solutions. A scheme of preventive fault-tolerant QoS multicast routing is therefore proposed on the basis of ant colony algorithm and dual-tree protection mode. Aiming at minimizing the fault rate of light tree, a principle and standby light tree are set up to meet the requirement of restriction on QoS for fault tolerance. Simulation results show that the proposed scheme is both feasible and effective with better performance. References | Related Articles | Metrics

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Reactive energy-saving dynamic-clustering algorithm in wireless sensor networks Guo, Bin (1); Li, Zhe (1); Liu, Jun (1); Geng, Rong (1) 2007, 28 (4):  501-504.  DOI: - Abstract ( 372 )   HTML   PDF (323KB) ( 427 )   A reactive energy-saving dynamic-clustering (REDC) algorithm is proposed according to the field data in network where the nodes are driven by events. All the information is classified by setting local and action thresholds of those nodes from which a temporary cluster-head is selected for the fusion of all the data acquired, according to the similarity and isochronism of local field data. At the same time, two kinds of energy-saving strategies are provided to balance the further network power consumption, thus lengthening the network lifetime considerably. Simulation results revealed that the REDC algorithm is really efficient. References | Related Articles | Metrics

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Deformation effect on microstructure and mechanical properties of hot-rolled dual-phase steel Zhang, Hong-Mei (1); Xu, Yun-Bo (1); Liu, Zhen-Yu (1); Wang, Guo-Dong (1) 2007, 28 (4):  505-509.  DOI: - Abstract ( 273 )   HTML   PDF (834KB) ( 752 )   The effects of reduction, coiling temperature and finish rolling temperature on the refinement of microstructure and mechanical properties of hot-rolled dual-phase steel were investigated in laboratory. It was found that the deformation process parameters affect greatly the microstructure and mechanical properties and there are three typical microstructural morphologies, which cause the hot-rolled dual-phase steel in different toughening mechanism and mechanical properties. The tensile strength of the steel developed in the laboratory by controlling the process parameters with Mn and Si as main alloying elements comes up to the Grade 780 MPa with high percentage elongation. References | Related Articles | Metrics

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Effect of microalloying on ultrafine-grained microstructure of plates Wang, Li-Jun (1); Yao, Lian-Deng (2); Ren, Hai-Peng (1); Liu, Chun-Ming (1) 2007, 28 (4):  510-513+521.  DOI: - Abstract ( 222 )   HTML   PDF (1442KB) ( 662 )   The microstructure evolution, precipitation behavior of carbonitride as microalloying element and its effects on deformation induced ferrite transformation (DIFT) of mild steel with various Nb, V (N) content were investigated on a Gleeble 1500 thermomechanical simulator through multi-pass thermocompression in the temperature range of 820-790°C to simulate the finish rolling process of plates. The results showed that part of austenite is transformed into ferrite through DIFT with reversed or meta-dynamic transformation found at intervals of deformation and depending on its temperature; in the microstructure the mean grain size is less than 5μm through the quick chilling after multi-pass deformation; DIFT is inhibited by adding V only to the steel to get the microstructure refined, while adding V-N compound to the steel will enhance DIFT to coarsen the microstructure; adding Nb to the steel will not inhibit DIFT but get the microstructure refined remarkably; the slower the chilling rate after deformation, the more apparent the difference between such steel. It was revealed that the effects of microalloying elements are correlated to the dissolution and precipitation behavior of carbonitride. References | Related Articles | Metrics

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Strain rate vector inner-product during strip drawing or extrusion in cylindrical coordinate system Zhao, De-Wen (1); Wang, Gen-Ji (1); Liu, Xiang-Hua (1); Wang, Guo-Dong (1) 2007, 28 (4):  514-517.  DOI: - Abstract ( 254 )   HTML   PDF (2416KB) ( 536 )   A new integration method is proposed to simplify the strain rate vector inner product by the mean value theorem in a cylindrical coordinate system. The equivalent strain rate of the strip passing through a wedge-shaped die during drawing/extrusion for plane deformation is first expressed in terms of two-dimensional vector. Then, the strain rate ratio function and direction cosine of the vector are determined by the integral mean value theorem. Finally, the termwise integration and summation of the inner product are done to give an upper-bound analytical solution to the stress state factor nσ and optimal die angle αopt. An example is given to compare the stress state factors thus solved under conditions of different α and m values with those by Avitzur's elliptic integral. The results show that if α = 15° and the friction factor m varies, the error of the value of drawing force by this analytical solution relative to that by the numerical solution resulting from elliptic integral isn't higher than 0.05%, and the absolute error of the stress state factor resulting from elliptic integral ξ(α) isn't higher than 0.002. In addition, the ultimate pass reduction Ε increases with increasing αopt and decreasing m. References | Related Articles | Metrics

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Effect of roll gang on the strip temperature field of work piece during TSCR Deng, Tian-Yong (1); Wu, Di (1); Xu, Yun-Bo (1); Zhou, Xiao-Guang (1) 2007, 28 (4):  518-521.  DOI: - Abstract ( 221 )   HTML   PDF (537KB) ( 725 )   Finite difference method was used to simulate the temperature field of work piece during thin slab continuous rolling (TSCR). The model incorporated the effects of radiation, heat convection and heat conduction between rolls and work piece, as well as the heat due to deformation and friction of work piece is comparatively small. It was shown that the thermal effect of roll gang on the temperature field drop about 14-18°C. However, the temperature difference between the top and bottom of work piece is great in the process before finish rolling, up to 20-25°C. The predicted values from the model taking the effect of roll gang into consideration are close to the measured values. References | Related Articles | Metrics

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Stepwise regression analysis model to calculate finishing temperature during hot strip rolling Gong, Dian-Yao (1); Xu, Jian-Zhong (1); Liu, Xiang-Hua (1); Wang, Guo-Dong (1) 2007, 28 (4):  522-524+528.  DOI: - Abstract ( 266 )   HTML   PDF (205KB) ( 684 )   Based on the in-situ data logging in a steel works in China, a linear model was developed to calculate the finishing temperature during hot strip rolling by way of stepwise regression analysis. The main influencing factors on finishing temperature were taken into account in modeling, such as rolling speed, workpiece thickness at entry and exit of finish rolling and inter-stand cooling water flow rate. A simulative computation was therefore done according to the linear model before starting the self-learning of model regression coefficients, then the computational results were compared with actual data logging. It was found that 70.1% of the difference between them is less than 15°C, which implies that the computational results of the model can meet the precision control requirement for finishing temperature. Furthermore, because of the limitation of the linear regression model, the self-learning of regression coefficients of the model was discussed. References | Related Articles | Metrics

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Study on growth control of bioleaching thermophilic strain HQ0211 by zinc ions Tong, Lin-Lin (1); Jiang, Mao-Fa (1); Yang, Hong-Ying (1); Fan, You-Jing (2) 2007, 28 (4):  525-528.  DOI: - Abstract ( 199 )   HTML   PDF (902KB) ( 548 )   The influence of zinc ions on the growth of the bioleaching thermophilic strain HQ0211 was studied. Experimental results showed that if the concentration of zinc ions in liquid medium is lower than 1.0 × 10-3 mol/L, the growth of the strain is expedited, i.e. zinc ions play a nutrient role of growth. However, the growth is inhibited if the concentration is higher than 1.0 × 10-2 mol/L, i.e. zinc ions play a toxic role of growth. In case the concentration is down to 8 × 10-5 mol/L, the strain grows quickest. It was revealed that an appropriate amount of zinc ions enable the strain to grow quickly so as to improve the oxidizing activity and bioleaching ability of the strain, thus enhancing the industrial capacity and economic benefits. References | Related Articles | Metrics

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Experimental study on gas/air flow splitting in pelletizing shaft furnaces Dong, Hui (1); Cai, Jiu-Ju (1); Wang, Guo-Sheng (2); Zhang, Ya-Tian (1) 2007, 28 (4):  529-532.  DOI: - Abstract ( 199 )   HTML   PDF (407KB) ( 1179 )   A cold-state experimental setup was built to study the constructional and operating parameters affecting the gas/air flow direction and flowrate in pelletizing shaft furnace (PSF). Some conclusions are therefore drawn that constructional and operating parameters are both the main influencing factors on the gas/air flow splitting in PSF. Among the operating parameters, the flowrate ratio of roasting gas to cooling air, i.e. the inflow flowrate ratio k is the key influencing factor on gas/air flow splitting, and the flow-down roasting gas/air tends to increase and the flow-up cooling gas tends to decrease with the increase of inflow flowrate ratio k, and vice versa. It is found that k is linear relation to the flowrate ratio of the cooling air into internal vertical air channels (IVAC) to the flow-up roasting gas under certain operating conditions. Among the constructional parameters, the widths of both roasting zone and IVAC and the heights of both preheating-roasting zone and soaking zone are the main influencing factors on gas/air flow splitting in PSF. In case the width of roasting zone increases or the width of IVAC or the height of preheating-roasting zone decreases, the flow-up cooling air tends to decrease and the flow-down roasting gas tends to increase with the critical k increases. References | Related Articles | Metrics

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Experimental study on characteristics of ashes from hospital waste incineration Liu, Han-Qiao (1); Cai, Jiu-Ju (1); Qi, Peng-Fei (1); Tian, Dong-Qing (1) 2007, 28 (4):  533-536.  DOI: - Abstract ( 226 )   HTML   PDF (961KB) ( 601 )   Solidification/stabilization operation of the ashes from hospital waste incinerator depends on their physicochemical properties. The characteristics of three ashes samples from different positions in the incinerator were investigated with XRF, XRD, SEM and AAS for their chemical composition, mineralogy, morphology, metal contents and leaching behavior of heavy metals, aiming at finding a safe and efficient disposal method. The results indicated that the bag fly ash (FAl) has high chloride/sulphate content and a feature of loss on ignition (LOI) as well as the alkali metal, and its leached concentrations of Cd, Zn and Pb in FA1 far exceed landfill regulatory thresholds of the hazardous waste and should be pretreated prior to landfilling. The CaSO4 is found very high in the flue ash (FA2) and bottom ash (BA) mainly consists of silicates, and they have low leachability and could be classfied as non-hazardous waste. References | Related Articles | Metrics

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AC impedance spectrum of electro-deoxidation reaction of silicon dioxide Wang, Shu-Lan (1); Zhang, Hua (1); Zhuang, Li-Jun (1) 2007, 28 (4):  537-540.  DOI: - Abstract ( 386 )   HTML   PDF (998KB) ( 811 )   AC impedance spectrum was used to study the electro-deoxidation reaction of silicon dioxide in the equalmolar molten salt CaCl2 and NaCl. The AC impedance spectra showed that the electro-deoxidation reaction of silicon dioxide is a two-step reaction and corresponding to the two reduction current peaks in the cyclic voltammetry curve. In the XRD pattern the intermediates SiO, CaSiO3 and Ca2SiO4 were found in the reaction system. By fitting the AC impedance spectra with equivalent circuits, the charge transfer resistance, double layer capacitance and activation energy during the reaction were obtained. In the low voltage range the charge transfer resistance and activation energy decrease with increasing cathodic voltage which implies that charge transfer is the rate control step of the electro-deoxidation of silicon dioxide. The results of the study are important to improve the current efficiency in the electro-deoxidation process of silicon dioxide. References | Related Articles | Metrics

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Study on the electrolytic densities of Na3AlF6-AlF3- Al2O3-CaF2-LiF-NaCl system Kan, Hong-Min (1); Wang, Zhao-Wen (1); Ban, Yun-Gang (1); Qiu, Zhu-Xian (1) 2007, 28 (4):  541-544.  DOI: - Abstract ( 149 )   HTML   PDF (393KB) ( 1156 )   The density of the aluminum electrolyte system where NaCl was used as an additive to substitute partly for LiF was studied. The electrolytic density was measured by an electronic balance connected to computer port according to the Archimedian law with an error less than 1%. Then, the measured electrolytic densities of Na3AlF6-AlF3 (10.87%-16.67%)-Al2O3-CaF2-LiF (0-6%)-NaCl (0-6%) system were analyzed through a 4-factor/4-level orthogonal experiment to develop a mathematical model based on those experimental results, i.e. ρt (g · cm-3) = 2.8971-0.003 07AlF3 (w/%) + 0.003041LiF (w/%)-0.00932NaCl (w/%)-0.00085t (°C). The effects of cryolite ratio and LiF and NaCl concentrations on the densities were investigated. The results showed that the addition of NaCl decreases the density of aluminum electrolyte while the addition of LiF increases that of acidic electrolyte, but mixing the two additives properly may get excellent result. The more the NaCl used to substitute for LiF, the lower the electrolytic density. References | Related Articles | Metrics

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Application of wavelet transform to crack fault diagnosis for rotor systems Ren, Zhao-Hui (1); Ma, Hui (1); Wang, De-Ming (2); Song, Nai-Hui (1) 2007, 28 (4):  545-548+552.  DOI: - Abstract ( 222 )   HTML   PDF (633KB) ( 708 )   Simulation experiments were carried out on a test rig for single-span rotor system with crack fault and the collected fault signals were analyzed by way of a 3-D waterfall spectra in combination with reassigned wavelet scalogram. The results showed that the combination can reveal the frequency structure of signal better, especially the relatively low-energy twofold frequency component which can be measured at half of the critical speed. It was found that an one-half order harmonic or subharmonic resonance comes up at twofold critical speed and with the crack deepened further, high order harmonics occur. These frequency characteristics features can be regarded as a reference to diagnosing the crack fault. References | Related Articles | Metrics

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Mathematical models study on coaxial error Chen, Li-Jie (1); Zhang, Lei (1); Zhang, Yu (1) 2007, 28 (4):  549-552.  DOI: - Abstract ( 240 )   HTML   PDF (168KB) ( 495 )   A solution to the key problem of evaluating coaxial error in rectangular coordinates was provided. According to the definition of coaxial error as given in Chinese National Standard, a mathematical model based on least square method was developed to evaluate coaxial error, where the origin of coordinate could be selected randomly, and all sampling points were not required at intervals of equal angle. The simulation results indicated that the model is theoretical correct and practical, based on which the coaxial error to meet the requirement for minimum can be directly computed by way of the 4-D non-restraint optimization algorithm. The model can be used for either the 3-D coordinate measuring machines or other intelligent instruments for parts measurement. References | Related Articles | Metrics

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Analysis of wavy vibration of rotating thin cylindrical shells Li, Jian (1); Guo, Xing-Hui (1); Li, Yong-Gang (1) 2007, 28 (4):  553-556.  DOI: - Abstract ( 512 )   HTML   PDF (408KB) ( 911 )   A complex analysis is made to study the linear wavy vibration of a cantilever rotating thin cylindrical shell under the action of a normal exciting force with damping taken into account, based on Donnell's theory of cylindrical shell. The results show that the complex analysis is available to solve the problem of such rotating wavy vibration. In the solution the condition that the real parts of both forward and backward traveling waves are equal to zero can be used to determine the frequencies and rotating speeds of resonance, while the virtual parts can determine the response values. There are two resonance frequencies when the rotating thin cylindrical shell vibrates linearly. The response curve of the wavy vibration is a beat-frequency one and its amplitudes relate to the damping ratio in wave mode. In general, the resonance amplitude of backward traveling wave is bigger than that of forward traveling wave. References | Related Articles | Metrics

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Method to locate driver face feature points by chrominance distribution Yang, Ying (1); Zhao, Guang-Yao (1); Yang, Jia (2); Sheng, Jing (1) 2007, 28 (4):  557-560.  DOI: - Abstract ( 275 )   HTML   PDF (273KB) ( 538 )   A new method is proposed to locate driver face feature points by chrominance distribution. Based on the face that human lips are red, the luminance of color images acquired by CCD is normalized and the images are projected into an UV space coordinate system composed of color data. Separating the lip region from the projection of images in accordance to red chrominance, the shape of lips is determined by way of combining edge extraction with red pixels, with the state feature points of mouth determined by way of bracketing and approaching. Then, the eye region is preliminarily determined according to face figure/size. Based on the fact that Chinese eyeballs are mostly black, the same method is used to determine and identify the state feature points during eye closing/opening. Experimental results showed that the proposed method is effective to getting rid of the shadow disturbance around lips and eyes, regardless of whether the luminance is even, with an accuracy offered up to higher than 94.3%. The method is thus regarded as real time, accurate and available to be an important criterion for whether a driver is in a state of tiredness. References | Related Articles | Metrics

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DSP-based real-time inspection system for strip surface defects Han, Ying-Li (1); Yan, Yun-Hui (1); Li, Jun (1); Su, Wei-Xing (1) 2007, 28 (4):  561-565.  DOI: - Abstract ( 238 )   HTML   PDF (995KB) ( 577 )   Taking account of both software and hardware, the effective real-time high-speed inspection as an on-line problem to solve was investigated. The recognition process of strip surface defect images restricting the real-time aspect was separated, then it was processed specially by a digital signal processing (DSP) chip, and simultaneously recognized by a secondary classifier of support vector machine that combines the recognition rate with accuracy. By such an inspection system, the correct recognition ratio of defect images comes up to 98% with time controlled lower than 10 ms. It was proved theoretically and experimentally that the advanced TMS320C6416 DSP image processing platform thus developed can meet well the actual requirement of on-line inspection for strip surface defects in both speed and accuracy. References | Related Articles | Metrics

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Influencing factors on oil-mist concentration during atomized lubrication Chen, Jian-Wen (1); Song, Jin-Chun (1); Zhang, Zhi-Wei (1); Qiu, Ye (2) 2007, 28 (4):  566-568.  DOI: - Abstract ( 308 )   HTML   PDF (208KB) ( 580 )   The characteristics of lubricant flow were discussed hydromechanically at the inlet of an atomizer, then the mathematical models were developed for the oil-mist concentration. It was found through theoretical analysis that the influencing factors on oil-mist concentration are mainly the lubricant temperature and venturi throat pressure. The data relevant to the influencing factors were obtained from tests with relationship curves plotted. The results showed that the best atomizing effect is found under the conditions that lubricant temperature is 50-60°C, air temperature is 60-80°C and air pressure is 180-240 kPa. References | Related Articles | Metrics

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Domestic wastewater treatment by submerged flat MBR system Zhu, Tong (1); Xie, Yuan-Hua (1); Liu, Fang (1); Wang, Yun-De (1) 2007, 28 (4):  569-572.  DOI: - Abstract ( 255 )   HTML   PDF (441KB) ( 572 )   The treatment of the mixed wastewater from college dormitory and canteen by a submerged flat membrane bioreactor (MBR) system was studied experimentally. The anaerobic/oxic (A/O) MBR system has a capacity to treat wastewater up to 4 m3/d, through which the B0D5 and CODCr in the influent are 90-450 mg · L-1 and 120-900 mg · L-1, and they in the effluent are 5-25 mg · L and 8-45 mg · L-1 respectively, i.e. the removal rates are both over 90%. In addition, how to get rid of color contamination of effluent and membrane fouling was investigated. It was found that activated carbon can remove the contaminated color effectively, and the membrane can work well after cleaned up mechanically and chemically. A conclusion was drawn that the submerged flat MBR system is applicable to medium/small-scale domestic even industrial organic wastewater treatment with broad prospects in application. References | Related Articles | Metrics

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Lorentzian decomposition for Raman spectrum of hydrogenated diamond-like carbon films Lin, Zeng (1); Ba, De-Chun (1); Wang, Feng (1) 2007, 28 (4):  573-575.  DOI: - Abstract ( 360 )   HTML   PDF (210KB) ( 873 )   The a-C:H (hydrogenated diamond like carbon) films were deposited on stainless steel substrates by means of radio frequency plasma enhanced chemical vapor deposition process and the Raman spectrum was applied to the characterization of the microstructure of the films. Especially, the Lorentzian decomposition was carried out for the Raman spectra to estimate the sp3 content in the films deposited so as to investigate the effects of the voltage during deposition process and transition layer on the growth of film and sp3 content in the resultant film. The results indicated that Lorentzian decomposition for the Raman spectra can effectively characterize the microstructure of a-C:H film, and in the deposition process the voltage and transition layer affect greatly the growth of a-C:H film. Under conditions that the characterization was done, the sp3 content in a-C:H film deposited under 2500 V with Ti/TiN/TiC as transition layer comes up to its maximum value. References | Related Articles | Metrics

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Effect of different stress paths on Kaiser effect of rock acoustic emission Li, Yuan-Hui (1); Yuan, Rui-Fu (1); Zhao, Xing-Dong (1) 2007, 28 (4):  576-579.  DOI: - Abstract ( 266 )   HTML   PDF (977KB) ( 801 )   To understand the characteristic of Kaiser effect along different stress paths during cyclic load acting on rock, a numerical computation was conducted using the rock failure process analysis software RFPA2D for the characteristics of acoustic emission (AE) along three different stress paths in rock specimens. The results showed that the Kaiser effect is still clearly observed in the subsequent cycle when the specimens are under cyclic load though a big difference between KF values (the stress value at Kaiser effect point) and previous max stress value is found. It was revealed that what was actually recorded in the Kaiser effect memory is the damage level within rock other than the max stress acting previously on the specimens. So, if sampling from parent rock, the stress value measured from observing KF value by uniaxial compression AE testing in laboratory is different greatly from that in parent rock. The conclusion is significant to understanding the essence of Kaiser effect and how to use it to determine the in-situ stress. References | Related Articles | Metrics

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Surface modification of calcium sulphate whiskers Yin, Wan-Zhong (1); Wang, Xiao-Li (1); Han, Yue-Xin (1); Yuan, Zhi-Tao (1) 2007, 28 (4):  580-583.  DOI: - Abstract ( 302 )   HTML   PDF (380KB) ( 1443 )   The borate surfactant SBW-181 was used for the modification experiments of calcium sulphate whiskers on the conditions of individual factors. Influences of the technical factors such as surfactant dosage, modification temperature/time and stirring speed on the surface modification of calcium sulphate whiskers were studied. The modified calcium sulphate whiskers were characterized with activation index, contact angle, SEM and IR spectrum analysis, and the results indicated that the SBW-181 has good effect on surface modification of calcium sulphate whiskers. On the optimum technological conditions, the activation index of modified product is 0.996 with a contact angle of 103.4°. A reaction model was developed relevantly for the whiskers and surfactant, and a conclusion drawn from that plays a role of guidance in the industrialized surface modification of calcium sulphate whiskers as a theoretical reference offered for their applications. References | Related Articles | Metrics

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Theoretical analysis of electrorheological isolator for adjustable hysteresis modeling Yang, Yang (1); Ou, Jin-Ping (2) 2007, 28 (4):  584-588.  DOI: - Abstract ( 190 )   HTML   PDF (495KB) ( 426 )   The design principle of an electrorheological isolator for adjustable hysteresis modeling is put forward with its basic performance analyzed. Then, a single-layer electrorheological device and electrorheological isolator for adjustable hysteresis modeling are designed with performance analysis, and four types of hysteretic damping force models of the two dampers are therefore developed through numerical simulation, i.e. quasi-friction model, displacement-limit I model, displacement-limit II model and quasi-viscous model. Effects of the parameters in those models are discussed. The results show that the mechanical properties of isolator can be controlled easily by changing the types of the hysteretic damping force models through regulating the functional relation between external electric field intensity and shear deformation of plate electrodes, thus obtaining the isolators with different hysteretic performance. Keeping other parameters constant, increasing the diameter of plate electrodes, the parameter A or the coefficient α, or decreasing the interval between plate electrodes can improve the performance of the electrorheological isolator anyhow. References | Related Articles | Metrics

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China's environment: Environmental load and efficiency Wang, Qing (1); Gu, Xiao-Wei (1); Wang, Jun (1); Ding, Yi (1) 2007, 28 (4):  589-591.  DOI: - Abstract ( 240 )   HTML   PDF (734KB) ( 527 )   Two indicators, domestic environmental load and efficiency, are defined to measure the aggregate environmental pressure and the comprehensive environmental efficiency of a country's economic operation, respectively. The indicators are applied to study empirically China's economic development from 1990 to 2002. The results show that China's environmental efficiency increased at an annual rate of 5.6% in this period, which indicated that a relative environmental depressurization was realized to a certain degree with economic development. On the other hand, it is revealed that more than 90% of the total domestic environmental load comes from the excavation and disposal of domestic hidden flow of which about 60% to 70% was caused by agriculture related activities. It follows that the end-of-pipe pollution control alone is far from solving efficiently the environmental problems as a whole, and the fundamental way is to reduce the resource demand at the source and pay more attention to the environmental impact due to agriculture. References | Related Articles | Metrics

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Input-output analysis in application to study on China's ecological footprints Liu, Jian-Xing (1); Wang, Qing (1); Gu, Xiao-Wei (1); Li, Guang-Jun (1) 2007, 28 (4):  592-595.  DOI: - Abstract ( 236 )   HTML   PDF (203KB) ( 779 )   The ecological footprints of three industrial sectors in China were studied through input-output analysis. In view of the formation of the primary, secondary and tertiary industries, their ecological footprints were 0.9626, 0.3912 and 0.1844 hm/cap respectively. But, in view of the different modes of land occupation, the direct ecological footprints due to the occupation of primary industry become the absolute majority, i.e. 0.9580 hm /cap or 62.3% of the total, and the next one was the indirect ecological footprints due to that of secondary industry, i.e. 0.3433 hm2/cap or 22.3% of the total. The data implies that the impact of primary industry on ecological footprints is much higher than the average level of the impact of other industries, and the primary industry played a key role in controlling the overall level of ecological footprints since it demanded a dominant part of ecological footprints in the process of national economic growth. Considering the impact of ecological footprints on the environment and economic development, the industrial structure should be readjusted in order of primary, secondary and tertiary. References | Related Articles | Metrics

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Evaluation model based on fuzzy rule for logistics centers Zhang, Chuan (1); Pan, De-Hui (1) 2007, 28 (4):  596-599.  DOI: - Abstract ( 228 )   HTML   PDF (340KB) ( 505 )   To locate logistic distribution centers, a location/evaluation index system is built. Then, the fuzzy Delphi method is used to synthesize expert comments so as to give the relative index weights and fuzzy interval numbers to the satisfaction of the indices at low levels, while the fuzzy interval numbers to the satisfaction of the indices at high levels in different alternatives are given through hierarchical association. Synthesizing all the evaluation indices at high levels, the final overall fuzzy marks are given to all alternatives, and they are ranked with interval numbers. Thus, a priority order is provided for the overall selection of logistics as a reference for actual decision-making. An example is given to verify the validity of the proposed model. References | Related Articles | Metrics

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Competency model of top managers of state-owned enterprise in China's northeastern old industrial base Zhang, Lan-Xia (1); Wang, Jun (1); Wang, Xue (1); Zhao, Jin-Peng (1) 2007, 28 (4):  600-604.  DOI: - Abstract ( 221 )   HTML   PDF (284KB) ( 630 )   Some ways including literature retrieval, behavioral event interview (BEI), questionnaire survey and multivariate statistics were used to explore the competency model of top managers of state-owned enterprises in China's northeastern old industrial base. The data about 260 relevant top managers were analyzed through exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). A model was thus developed to characterize their competence in view of the following nine categories, i.e. the personnel maturity, strategical decision-making ability, thinking of conceptual analysis, team leadership, coordinating/controlling ability, communicating ability, discernment, influenceability and motivation. References | Related Articles | Metrics

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Research on the interlaminar short fiber toughened composite panel under impact load Zhang, Feng-Peng (1); Liu, Hai (1); Huang, Bao-Zong (1) 2007, 28 (4):  605-608.  DOI: - Abstract ( 269 )   HTML   PDF (443KB) ( 562 )   The delamination crack propagation in composite panels involving interlaminar short fiber under impact load was studied using geometrically nonlinear finite element method (FEM), based on the total Lagrangian formula. The Newmark method was used to solve the dynamics equation. FEM was improved with an effective virtual crack closure technique to evaluate the energy release rate as the criterion for crack propagation. The crack propagation was simulated by node coupling/partition, while the effect of interlaminar short fibers was simulated by the bidirectional spring elements. The bridging strength between short fibers was thus modified by changing the spring stiffness. Contact elements were set up on crack surface and in the area in contact with impact, with the contact force computed through the penalty function algorithm to analyze the bridging effect of interlaminar short fibers on the crack-tip stress field and energy release rate. The results showed that the bridging effect of interlaminar short fibers can effectively reduce the stress concentration and crack-tip energy release rate, thus toughening significantly the short fibers. References | Related Articles | Metrics