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15 August 2003, Volume 24 Issue 8 Previous Issue    Next Issue
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Hybrid modeling and prediction of the dynamic BOF steelmaking process Wang, Yong-Fu (1); Li, Xiao-Ping (1); Chai, Tian-You (1); Xie, Shu-Ming (2) 2003, 24 (8):  715-718.  DOI: - Abstract ( 33 )   HTML   PDF (250KB) ( 891 )   A new framework was presented for the accurate modeling and prediction of the reblown oxygen and the added coolant in dynamic basic-oxygen-furnace (EOF) steelmaking processes. The proposed method takes advantages of the modeling approach based on mechanism and uses adaptive neural-network-fuzzy-inference system (ANFIS) to compensate for the BOF modeling uncertainties based on mechanism. In the ANFIS compensating model, the first-order Takagi-Sugeno type fuzzy rules were employed and a hybrid algorithm combining the least square method (LSM) and the gradient descent method was adopted to obtain the model structure. The practical data of a 180 t converter were simulated. The simulated results are close to the practical values. The method is practicable and effective. References | Related Articles | Metrics

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Design and application of dynamic cost control system based on MES Liu, Wei (1); Chu, Yan-Gang (1); Chai, Tian-You (1) 2003, 24 (8):  719-722.  DOI: - Abstract ( 35 )   HTML   PDF (236KB) ( 745 )   On the background of some ore concentration plant, the dynamic cost control system structure based on the three layers structure of ERP/MES/PCS was presented with the support of network, database and information technologies. This system is objected for production process, collects cost data of all working procedures according to the certain cost center, monitors cost indexes, and completes dynamic cost accounting. Using the model to decompose, forecast and analyze cost, the system implements the dynamic cost control and the integration of the information flow, material flow and fund flow. The system was put in practice and great effect was obtained. References | Related Articles | Metrics

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Fault diagnosis for air pressure-flow control system of fermentation process Jia, Ming-Xing (1); Wang, Fu-Li (1) 2003, 24 (8):  723-726.  DOI: - Abstract ( 29 )   HTML   PDF (177KB) ( 493 )   The fault diagnosis for air pressure-flow control system of fermentation process was proposed. The system linear model was established, it contains some uncertainties consisting of linearization error and unknown disturbance. To the sensor faults, a new fault diagnosis method was presented. The mix estimation of the influence of the uncertainties and the fault was given using residual information, then the fault value was calculated. Compared with the old methods, the method not only guarantees robustness of the algorithm, but also enhances the sensitivity of fault estimation. A simulation example was used to illustrate the results. References | Related Articles | Metrics

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Multi-sensor adaptive filtering based on neural network for leak detection of pipeline Lun, Shu-Xian (1); Zhang, Hua-Guang (1); Feng, Jian (1) 2003, 24 (8):  727-730.  DOI: - Abstract ( 37 )   HTML   PDF (180KB) ( 804 )   The low signal-to-noise ratio makes the signal processing of the leak detection of pipeline difficulty. The adaptive noise cancellation based on neural network is proposed to achieve the H2 optimal reconstruction and a desired robust against the effect of uncertainties in signal processing. In order to implement leak detection and location of pipeline correctly, multi-sensor signals are employed to overcome the shortcomings of creditability in case of single-sensor signal. The designed method can adjust the weights of linear combiner (LC) adaptively, and overcome the shortcomings of the method based on the averaging method of all sensor signals, which may lose accurate information and cause a large estimated error. The design method can not only obtain simplicity of implementation and conservation of operation time but also achieve better reconstruction performance than the method in the pressure and flow signal processing of the leak detection of pipeline. References | Related Articles | Metrics

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Development on leak detection and location system for oil pipeline Feng, Jian (1); Zhang, Hua-Guang (1); Lun, Shu-Xian (1); Wang, Zhan-Shan (1) 2003, 24 (8):  731-734.  DOI: - Abstract ( 41 )   HTML   PDF (148KB) ( 801 )   The leak detection and location system for oil pipeline was developed on Visual C++ software platform. Equipments of industrial field and devices of data acquisition were used as hardware platform. The system integrates flow difference detection technology with negative pressure wave location technology. Sample synchronization was solved by GPS in the distributed system, and special point of signals with noise was caught by wavelet transform method. The running curve chart can be displayed on screen. With database technology, the real-time running data can be stored in database in order to query and analyze the cause of fault. The system has superior precision in location in few minutes. Not only the system cost low, but also the system is stable and reliable. The system function can be extended easily. The system can be used both in experiment simulation and in industrial field monitoring. References | Related Articles | Metrics

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Study of terabit router architecture Fan, Li-Jun (1); Ren, Xiu-Li (1); Quan, Cheng-Bin (1); Luan, Gui-Xing (2) 2003, 24 (8):  735-738.  DOI: - Abstract ( 37 )   HTML   PDF (238KB) ( 1078 )   With the dramatic increment and development of traffic on the backbone, it's impossible for the ISPs to upgrade their core routers frequently, and the scalability of the core routers becomes the key issue for protecting investment. As the scalability of traditional routers based on crossbar switch architecture is poor, the scalable distributed switch architecture must be adapted in terabit routers. Summary of the latest research achievements and the new features of terabit routers are discussed. Based on the study of three-dimensional ring architecture, three-dimensional torus architecture and multi-dimensional hypercube architecture, a thorough analysis of the distributed architecture utilized in modem terabit routers is presented. The prospect of terabit router was investigated. References | Related Articles | Metrics

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Fair and efficient dynamic polling scheme Ren, Xiu-Li (1); Fan, Li-Jun (1); Quan, Cheng-Bin (1); Luan, Gui-Xing (2) 2003, 24 (8):  739-742.  DOI: - Abstract ( 36 )   HTML   PDF (688KB) ( 597 )   Scheduling scheme is an important part in Bluetooth piconets. The pure round-robin polling scheme of Bluetooth has a significant impact on the system performance. An fair and efficient dynamic polling scheme was proposed-double-tokens dynamic polling scheme. The scheme has two important points. One is that all slaves are visited by the pseudo-random order in order to solve the unfairness among all slaves. The other is that the master-slave which holds tokens is scheduled first to reduce the length of the polling cycles. Previously-proposed polling schemes for Bluetooth were discussed. The scheme excels in throughput and delay behavior, and has a good fairness. References | Related Articles | Metrics

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Optimizing algorithm in determining the number of signals using wavelet packet decomposition Wang, Jin-Kuan (1); Xue, Yan-Bo (1); Liu, Zhi-Gang (1); Liu, Fu-Lai (1) 2003, 24 (8):  743-746.  DOI: - Abstract ( 44 )   HTML   PDF (265KB) ( 869 )   Detection of number of signals by information theoretic criteria is given. In the occasions of low signal-to-noise ratio (SNR) and large snapshots, incorrect estimation of signal number is often yielded with both Akaike Information Criteria (AIC) and Minimum Description Length (MDL). A wavelet packet decomposition (WPD) based algorithm is proposed to optimize MDL, which is addressed wpMDL. With the features of minimum prediction error and mode isolation, pseudo 2-D subband decomposition algorithm based on one-dimension (1-D) wavelet packet decomposition is introduced to not only improve the estimate performance but also save the computation by O(N4) compared with 2-D WPD. References | Related Articles | Metrics

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New method of discretization of continuous attributes based on rough set Tao, Zhi (1); Xu, Bao-Dong (1); Wang, Ding-Wei (1); Li, Ran (1) 2003, 24 (8):  747-750.  DOI: - Abstract ( 41 )   HTML   PDF (322KB) ( 820 )   Based on theory of the rough set, a new method of discretization of continuous attributes was presented. The traditional rough set theory can only deal with the discrete attributes in database. The concept of decision attribute support degree was proposed. Using feedback information from decision attribute support degree a new method of discretization of continuous attributes was proposed based on independent domain. The suggested method can improve the efficiency of knowledge reduction when the original decision table keeps stable. At the same time, the rule sets are simple with less segmental interval. The approach is encouraging and effective. References | Related Articles | Metrics

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Robust H∞ control for uncertain descriptor systems Piao, Feng-Xian (1); Zhang, Qing-Ling (1); Zhang, Guo-Shan (2) 2003, 24 (8):  751-754.  DOI: - Abstract ( 44 )   HTML   PDF (160KB) ( 580 )   This paper focuses on the problem robust H∞ control design for affine uncertain descriptor systems in both state and input matrices. Necessary and sufficient conditions for quadratic stabilization with a H∞-norm bound are derived by a generalized algebraic Riccati inequality (GARI) with a so-called descriptor constraint. The relationship between the stabilization and the quadratic stabilization, and a design for the controller were given. The controller was obtained by the known information of the given uncertain descriptor systems. Finally, an example was given to illustrate the main results. References | Related Articles | Metrics

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Processor allocation strategies for parallel XML database systems Yu, Ya-Xin (1); Yu, Ge (1); Wang, Guo-Ren (1) 2003, 24 (8):  758-761.  DOI: - Abstract ( 51 )   HTML   PDF (172KB) ( 579 )   Depending on query workloads, the issues about processor allocation based on inter-query parallelism in parallel XML database system were discussed. Four processor allocation strategies, i.e., average allocation method, proportional allocation method, combinational allocation method and serial allocation method are proposed respectively, By experimental simulation, it is found that, in most cases, the performance under the combinational allocation method is the best. But, when the number of processors np is close to its maximum value nmax-p, the performance under the proportional allocation method becomes the best. Nevertheless, if np is less than 40 percent of nmax-p, the performance under the average allocation method is the worst. On the contrary, when np is greater than 40% of nmax-p, the seriary allocation method is the worst. References | Related Articles | Metrics

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Eliminating route oscillations based on asymmetric configuration of MRAI Zhang, Chun-Hong (1); Qu, Rong-Xin (1); Gao, Yuan (1) 2003, 24 (8):  766-769.  DOI: - Abstract ( 36 )   HTML   PDF (165KB) ( 514 )   This paper shows a method of asymmetric configuration for a BGP-specific timer, Minimum Route Advertisement Interval (MRAI), which can suppress BGP route oscillations and enhance BGP routing stability. BGP evaluation state and evaluation graph were used to analyze the dynamic behavior of a typical tri-node BGP route oscillations system in details and understand the behavior characteristic while the system oscillating. According to these results, a method of asymmetric configuration for MRAI was present to change the dynamic behavior of oscillations system and improve the convergence properties of BGP system. References | Related Articles | Metrics

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Dust dispersion characteristics in the devices used to test the minimum ignition energy Li, Xin-Guang (1); Dong, Hong-Guang (1); Radandt, Siegfried (2); He, Ji-Cheng (3) 2003, 24 (8):  770-773.  DOI: - Abstract ( 44 )   HTML   PDF (260KB) ( 783 )   The characteristics of dust dispersion such as whether the dust is evenly separated without any aggregation play on a significant role on the measurement accuracy of explosion parameters characteristics of dust dispersion in the 1.2 liters Hartmann bomb, in the 20 liters spheres and in the sieving tube with vibration were investigated respectively, by means of microscope and special sampling technique together. The results indicate that the best dispersion quality takes place in the 20 liters sphere dust, the dispersion quality in Hartmann bomb is the second and the quality in sieving tube with vibration stays at the end. In the case of the sieving tube with vibration, a lot of dust particles are aggregated with each other. Therefore, the sieving tube with vibration is not suitable to be used to measure the minimum ignition energy of dust explosion parameters. References | Related Articles | Metrics

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Effect of caustic ratio on structure and characteristics of sodium aluminate solution Wang, Ya-Jing (1); Zhai, Yu-Chun (1); Tian, Yan-Wen (1); Liu, Lian-Li (1) 2003, 24 (8):  774-776.  DOI: - Abstract ( 54 )   HTML   PDF (161KB) ( 1161 )   Effect of caustic ratio on structure and characteristics of sodium aluminate solution has been studied by methods of infrared and measurement of viscosity. It was obtained that the infrared peak of A1-O-A1 weakens gradually to disappear, and intensity of peak of Al(OH)4- also decreases with the increase of caustic ratio. Viscosity of the sodium aluminate solution increases rapidly below 70°C and increases slowly above 70°C with the increase of the caustic ratio. The results are explained by the structure of anion complex tied by hydrogen band in solution. References | Related Articles | Metrics

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Derivation of the revised k-Ε turbulence model considering the effect of magnetic field application Li, Bao-Kuan (1) 2003, 24 (8):  777-780.  DOI: - Abstract ( 31 )   HTML   PDF (179KB) ( 874 )   The research was motivated by the ongoing the electromagnetic refining and continuous casting of molten metal. The calculation method of the fluctuation electromagnetic force in turbulent field of electroconductive was proposed. Together fluctuation electromagnetic force with the Navier-Stokes equation, the revised k-Ε model considering the effect of magnetic field application was derived. The specific model equations for the static magnetic field application were used to calculate the velocity distribution. The results show that the revised k-Ε model considering the effect of magnetic field application tends to suppress the production of turbulence, and time-averaged momentum become somewhat large. Calculated velocity difference between the conventional and revised k-Ε model is small. References | Related Articles | Metrics

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Optimization of the precision control of hot Strip coiling temperature Han, Bin (1); Wang, Guo-Dong (1); Liu, Xiang-Hua (1); She, Guang-Fu (2) 2003, 24 (8):  781-784.  DOI: - Abstract ( 29 )   HTML   PDF (196KB) ( 761 )   Controlled cooling is the key technology for hot strip after rolling and coiling temperature control is the hardcore of the cooling process. Based on the improvement of cooling system in a hut snip mill, the online offset and problems in the coiling temperature control before reform were discussed, including the cooling capacity was insufficient to thick strip, the uniformity of the temperature control along rolling direction was poor relatively, etc. The improving measures were suggested on the cooling equipment, the cooling strategy and also the online mathematic control model. Model parameters are optimized at the same time. Self-adaptive capacity of mathematic model is improved meantime. The experimental result shows that the new system after being optimized offers steady and reliable performance, and high precision. References | Related Articles | Metrics

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Tension differential equation for flying gauge change of tandem cold rolling Wang, Jun-Sheng (1); Bai, Jin-Lan (1); Liu, Xiang-Hua (1); Wang, Guo-Dong (1) 2003, 24 (8):  785-787.  DOI: - Abstract ( 31 )   HTML   PDF (145KB) ( 516 )   Concept and rolling technique of flying gauge change for tandem cold rolling are explained. The stretch elongation of strip caused by tension between the stands was investigated during tandem cold rolling. Deformation differential equation and tension differential equation of flying gauge change were established by theoretical derivation according to stress and deformation distribution in the strip during flying gauge change of tandem cold rolling. The influencing factors of flying gauge change were discussed. It is found that tension differential equation of stable rolling is the special case of tension differential equation of flying gauge change during tandem cold rolling. References | Related Articles | Metrics

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Processing and growth mechanism of Al-doped rutile single crystal by flame fusion method Bi, Xiao-Guo (1); Sun, Xu-Dong (1); Zhao, Hong-Sheng (2) 2003, 24 (8):  788-791.  DOI: - Abstract ( 32 )   HTML   PDF (502KB) ( 1136 )   Yellowish and transparent rutile single crystal (ø20 mm × 30 mm) doped with 0.4% (atom fractions) Al2O3 was successfully produced by the flame fusion (improved Verneuil) method, whereas a pure rutile crystal without the doping is dark-blue and not transparent. It is shown that the substitution of Al3+ for Ti4+ reduces the number of Ti3+ due to the reduction of Ti4+, and reduces the non-natural oxygen vacancies and the amount of oxygen needed in the crystal growth. Oxygen diffusivity in the crystal is enhanced by the doping because the radius of A13+ is less than that of Ti4+ and oxygen diffusion path can be widened. Natural 2Al′Ti-V¨O defect pairs form in the Al-doped rutile to provide paths for the migration of oxygen ions. The introduction of Al into the crystal speeds up the diffusion of oxygen ions and eliminates the formation of substantive color centers. References | Related Articles | Metrics

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Development of the laser additive processing technology Liu, Chang-Sheng (1); Zhou, Li (1); Chen, Sui-Yuan (1); Cui, Hong-Wen (1) 2003, 24 (8):  792-794.  DOI: - Abstract ( 26 )   HTML   PDF (118KB) ( 781 )   State-of-the-arts method about laser additive processing, which is used to manufacture components and moulds by adding not reducing materials, is reviewed and discussed. This novel technology can be used in many fields such as military, automotive and aerospace industries. The surface roughness, inefficient filling, interlayer stress, porous and cracking can be eliminated by further development of the technology. Reactive laser additive processing will be a suitable method for synthesizing intermetallics and metal matrix composites. References | Related Articles | Metrics

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Phase constitution of ball-milling Fe-Ni powders with alcohol Zhang, Ya-Jing (1); He, Kai-Yuan (2); Cheng, Li-Zhi (2); Liu, Chang-Sheng (2) 2003, 24 (8):  795-797.  DOI: - Abstract ( 29 )   HTML   PDF (138KB) ( 623 )   The phase constitution and grain size of ball-milling Fe-Ni powders with alcohol as well as the lattice parameter evolution were investigated by X-ray diffraction. The condition of ball-milling was taken as follow: the weight ratio of ball to powder is 6:1, and the revolving velocity is 240 r/min. It is shown that the Fe concentration in the Ni fcc phase increases with the increase of the ball-milling time. The fcc solid solution γ(Fe-Ni) is formed after milling 12 h. The a-Fe is separated out gradually from the γ (Fe-Ni) phase above milling 18 h. The fcc γ phase becomes pure again Ni after milling 48 h. With the further increase of the milling time, the lattice parameter of the a-Fe phase decreases. With the increase of Ni atom fraction in the Fe-Ni mixture meanwhile that of fcc phase increases. References | Related Articles | Metrics

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Dynamics of pedestal looseness rotor system near the critical speed region Yao, Hong-Liang (1); Liu, Chang-Li (1); Zhang, Xiao-Wei (1); Wen, Bang-Chun (1) 2003, 24 (8):  798-801.  DOI: - Abstract ( 29 )   HTML   PDF (311KB) ( 756 )   A new type of dynamic model for pedestal looseness rotor system was built, and the dynamics of the rotor system in resonance region was analyzed by using KBM method. Some dynamic characteristics of pedestal looseness rotor system were found. The natural frequency of the fault system descends and the resonance region becomes greater, the high-order harmonic is evident, the system has 'soft' nonlinear characteristic. The affections on the faulting system of some system parameters, such as pedestal stiffness and shaft bending stiffness, were studied. The theoretical analysis conforms to the experimental results. References | Related Articles | Metrics

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Nonlinear dynamical response of rotor-bearing system with rub-impact fault Liu, Chang-Li (1); Yao, Hong-Liang (1); Li, He (1); Wen, Bang-Chun (1) 2003, 24 (8):  802-805.  DOI: - Abstract ( 35 )   HTML   PDF (250KB) ( 781 )   Based on the nonlinear dynamical model of the rotor-bearing system with rub-impact fault, the stability of the periodic motion of the system in unbalance-rotational speed and clearance-rotational speed plane were studied by the continuation-shooting algorithm for the periodic solutions of nonlinear non-autonomous dynamic systems. The stability of the periodic motion of the system decreases obviously when the unbalance increases. The small unbalance results in Hopf bifurcation, and the large unbalance results in doubling bifurcation. The critical speed of period doubling bifurcation increases when the clearance between rotor and stator decreases because rub-impact affects, the occurrence of oil whirl, and it does not change under large clearance because the oil whirl occurs before rub-impact or the rub-impact does not occur. References | Related Articles | Metrics

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Vehicle overall design CAD system based on parametric technology and expert system Huang, Xiao-Yun (1); Zhang, Guo-Zhong (1); Zhang, Feng-Ci (2) 2003, 24 (8):  806-809.  DOI: - Abstract ( 32 )   HTML   PDF (603KB) ( 740 )   The design tasks in vehicle overall design stage were analyzed. Based on the parameterizing technology and expert system technology the vehicle overall design CAD system was build combined with the database technology. In man-machine interactive mode, this system can define the design plan and give the overall layout graph in three dimensions. The overall structure of the system was given. The building and function of the overall-design parameter-selecting expert system were introduced briefly. The building and the function of the parametric graphical libraries were described. References | Related Articles | Metrics

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Dynamics of wave vibration relief for heavy pressure vessel Li, Yong-Qiang (1); Liu, Jie (2); Guo, Xing-Hui (1); Wen, Bang-Chun (2) 2003, 24 (8):  810-813.  DOI: - Abstract ( 47 )   HTML   PDF (1455KB) ( 401 )   The cause of welding residual stress and the principle of vibration stress relief for a pressure vessel were discussed. The wave vibration relief was put forward. The mechanism of wave vibration relief was analyzed from the dynamics aspect. Based on Flugge's shell equations, a method for calculating the eigen frequencies and modal solution was derived to the traveling-wave resonance response for a cylindrical shell. A speed formula for the rotating cylindrical shells at resonant frequency was obtained. Gauss method was exploited to calculate transcendental function of eigen frequency which can be solved with high accuracy. Calculation results of eigen frequency and axial wave stress were presented for a cantilever shell and mode shape was presented. References | Related Articles | Metrics

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Environmental treatment of papermaking wastewater by modified fly ash Yu, Xiao-Cai (1); Wang, En-De (1); Wang, Wu-Ming (1) 2003, 24 (8):  814-816.  DOI: - Abstract ( 33 )   HTML   PDF (107KB) ( 717 )   The ability of fly ash to treat papermaking wastewater was investigated. The results show that fly ash modified by the modification reagent of HC1:H2SO4=1:3 is effective to adsorb environmental harmful elements and substance in papermaking wastewater. When concentration of ODD is 800-1500 mg/L and pH 9-12 in the wastewater, 25 g modifying fly ash with particle size of 74-83 μm mesh can remove the COD, BOD, suspended solids and chrominance by 81.5%, 80.7%, 99.1% and 94% respectively. References | Related Articles | Metrics