Volume 33,Issue 12,2010 Table of Contents

  • Display Type:
  • Text List
  • Abstract List
  • 1  Power transformer fault fusion diagnosis using FMADM theory
    DU Lin YUAN Lei WANG You-yuan
    2010, 33(12):1-7. DOI: 10.11835/j.issn.1000-582X.2010.12.001
    [Abstract](2280) [HTML](0) [PDF 6.46 M](1386)
    Abstract:
    Large oil-immersed power transformer fault diagnosis is always directed at preventive test data, the preventive test data can not be got immediately, otherwise, it must be waited until power off and maintenance time. On the other hand, the accuracy and quantity for the field data collection is always limited. However, the symptoms phenomenon is a summary of a great deal experiences, to some extent, it can reflect the failure of transformer. Therefore, an idea that integrates both of the preventive test data and the symptom phenomenon in the transformer fault diagnosis is proposed. Through this method, all kinds of information can complement each other. First, the diagnosis to symptoms phenomenon is realized by introducing fuzzy multi-attribute decision making (FMADM) theory. Then, by adopting the fuzzy probability model, the failure probability of the preventive tests data is calculated. Finally, through D-S evidence theory, the results of the preventive test data and the symptom phenomenon can be integrated. The paper gives a novel diagnosis model which can be used as a kind of effective means through the given example.〖JP〗
    2  Simulation analysis of the thermal-electric analogy calculation model of transformer winding hot-spot temperature
    CHEN Wei-gen LI Meng-li SUN Cai-xin SU Xiao-ping HU Jin-xing
    2010, 33(12):8-13. DOI: 10.11835/j.issn.1000-582X.2010.12.002
    [Abstract](2377) [HTML](0) [PDF 6.54 M](1632)
    Abstract:
    The winding hot-spot temperature is one of the most critical parameters that determines the power transformer overloading capability and the aging rate of the oil-paper insulation. Based on the traditional thermal theory, the paper proposes a simulation model to predict transformer winding hot spot temperature taking into account oil viscosity changes with temperature, and combined with the thermal-electric analogy method and hot spot temperature rise model recommended by IEEE. The Runge-Kutta method is used to calculate top-oil temperature and winding hot-spot temperature of the transformer, and then compare them with the measured data obtained from the 100 kVA/5 kV (ONAN) experimental transformer. The simulation results are in good agreement with experimental data.
    3  Fault diagnosis based on least square support vector machine optimized by genetic algorithm
    LI Feng TANG Bao-ping LIU Wen-yi
    2010, 33(12):14-20. DOI: 10.11835/j.issn.1000-582X.2010.12.003
    [Abstract](2026) [HTML](0) [PDF 7.54 M](1294)
    Abstract:
    A new fault diagnosis model is proposed based on Multi-Class Least Square Support Vector Machine optimized hierarchically by Genetic Algorithm(GA). Original vibration signals are decomposed into several stationary IMFs. Then the instantaneous amplitude energy of the IMFs with fault modulation characteristics is computed and regarded as the input characteristic measure of the Poly-kernel Multi-Class LS-SVM for fault classification. EMD decomposition adaptively isolates the fault modulation signals from original signals. The differences among instantaneous amplitude energy vectors reflect the separability of different fault types. Adopting GA to optimize punish parameter and Poly-kernel parameters hierarchically can not only enhance fault prediction accuracy of Multi-Class LS-SVM with Poly-kernel, but also improve adaptive diagnosis capacity of LS-SVM. The GA-based hierarchical optimization is also applicable to Multi-Class LS-SVM with Lin-kernel, RBF-kernel or Sigmoid-kernel. The deep groove ball bearings fault diagnosis experiment shows the effectivity of this new model.
    4  Mixed-skill worker assignment optimization model for assembly line
    CAO Le WANG Biao LIU Fei LI Cong-bo
    2010, 33(12):21-26. DOI: 10.11835/j.issn.1000-582X.2010.12.004
    [Abstract](2704) [HTML](0) [PDF 5.10 M](1434)
    Abstract:
    Worker assignment is one of the key factors which influence the productivity of assembly line. The concept of post fitness is presented for the description of the competency of assembly workers. The post fitness which takes the operator skill level and accumulated assembling time as parameters is formulated. An optimization model for assembly worker assignment is constructed, and the objectives are maximizing the post fitness for each assembly station and minimizing the difference of post fitness among operators working in the same assembly line. A heuristic algorithm based on the fitness matrix is presented. An example is presented for illustration and the results suggest that the approach is feasible.
    5  Analysis on the self-locking effect and slipping motion of balls in the screw pair
    GONG Xian-sheng LIU Zhi-qiang QUAN Wei
    2010, 33(12):27-33. DOI: 10.11835/j.issn.1000-582X.2010.12.005
    [Abstract](2249) [HTML](0) [PDF 7.47 M](1398)
    Abstract:
    In view of self-locking and slipping phenomenon on restricting high-speed operation of ball screw, the model of ball screw is constructed and theoretical analysis of the movement feature of ball screw is made to reveal the reason of self-locking and slipping, and its influence on high-speed operation. Then the sliding speed format of ball screw is derived according to the movement rules of ball screw, and effective methods to avoid ball self-locking and slipping are put forward. Dynamics analysis is conducted with ADAMS software. Simulation results have confirmed the correctness of ball screw’ movement.
    6  Influence of high speed rotating cathode on the precision of micro-electrochemical drilling hole
    HUANG Shao-fu ZENG Yong-bin ZHU Di WANG Wei LIU Yong
    2010, 33(12):34-39. DOI: 10.11835/j.issn.1000-582X.2010.12.006
    [Abstract](2441) [HTML](0) [PDF 7.85 M](1302)
    Abstract:
    The metal parts with small holes are widely used in the fields of aeronautics and astronautics. micro-electro chemical machining (micro-ECM) provides a viable alternative for drilling micro/small holes on metal parts with acceptable quality. This paper discusses the phenomenon of gas film formation of a certain insulation effects on the cathode, because of the cathode high speed rotating. Effects of several process factors, such as the cathode rotating speed on the radial of overcut, value of surface roughness and stray corrosion are investigated. The results show possibilities of improving the machining accuracy by utilizing cathode higher speed rotating.
    7  Application of GO methodology in reliability analysis of supply chain
    ZHANG Gen-bao CHEN Guo-hua PANG Ji-hong REN Xian-lin ZHANG Shu-hui
    2010, 33(12):40-46. DOI: 10.11835/j.issn.1000-582X.2010.12.007
    [Abstract](1793) [HTML](0) [PDF 6.91 M](1229)
    Abstract:
    To study the accurate calculation and fault mode diagnosis of supply chain, a new method-GO methodology is applied in reliability analysis of supply chain. Through analyzing every important factor leading to success of supply chain system and taking three-tier supply chain as the object, GO model of reliability analysis of supply chain is developed. The model can not only calculate reliability of supply chain system in detail, but also diagnose its failure mode and calculate its importance, which provides the way for improving and optimizing supply chain system. The example is presented to prove the method’s feasibility and validity.
    8  Manufacturing resource modeling of complexassembly process under project-based manufacturing
    GUO Gang XU Jian-ping LUO Yu
    2010, 33(12):47-53. DOI: 10.11835/j.issn.1000-582X.2010.12.008
    [Abstract](2032) [HTML](0) [PDF 8.02 M](1227)
    Abstract:
    In an engineering-to-order (ETO) company, organization and management of manufacturing process is differ from common products because of the complexity of product. A project-based manufacturing (PM) planning model for product final assembly is proposed based on single-piece and small-batch production model so that the characteristics of complexity, specificity and high complex product manufacturing process can be met by means of projected-based manufacturing. The method of layered network planning under project-based manufacturing can transform the objects of planning from parts to assembly cell in the course of final assembly that has some time-based buffer for planning; simultaneously a resource-task matrix is build for the whole assembly process. The matrix can achieve the relatedness between manufacturing resources and assembly task, and follow the resources loads in order to realize the matching of planning and resource against project product.
    9  Influence on new tunnel mechanics behaviorinduced by construction about adjacent spacing
    LIU Xin-rong GUO Zi-hong WANG Ji-ming PEI Li LIN Zhi WANG Fang-qi
    2010, 33(12):54-59. DOI: 10.11835/j.issn.1000-582X.2010.12.009
    [Abstract](1710) [HTML](0) [PDF 7.06 M](1006)
    Abstract:
    This paper takes Chongqing Two-River Tunnel as the research background, based on the system for structure and surrounding rockmass of the highway tunnel, conducts a three-dimension model test about forked tunnel with different altitude to study new tunnel’s mechanics behavior induced by construction, and uses numerical simulation to analyze model domain. The results show that the displacement on new tunnel’s left hance is larger than the displacement on its right hance. Left hance displacement is larger than hance displacement of the single tunnel, and the right hance displacement is less than hance displacement of the single tunnel. The trend of hance displacement and crown settlement with different adjacent spacing is got. Normalizing hance displacement and crown settlement of model test, the relation between displacement and adjacent spacing is disclosed. The hance displacement and crown settlement gained by numerical simulation is close to the converted result of model test, which indicates that the model test data is consistent with the result of numerical simulation.
    10  Drift error compensation algorithm for fiber optic gyro based on T-S fuzzy modeling
    LIU Yu LU Yong-le ZENG Liao-Liao LI Dong-fu LI Lei-lei PAN Ying-jun
    2010, 33(12):60-64. DOI: 10.11835/j.issn.1000-582X.2010.12.010
    [Abstract](1717) [HTML](0) [PDF 5.00 M](1053)
    Abstract:
    A drift error nonlinear compensation algorithm for Fiber Optic Gyro (FOG) is presented based on T-S fuzzy model with the antecedent parameters identified by G-K clustering algorithm and the error model of T-S fuzzy model with the consequent parameters identified by least square algorithm. The computed results show that this model can compensate the original data effectively, while the error principles of FOG do not need to be understood well. Comparing with the original data, compensation with linear fitting and compensation with neural network, the absolute error of the proposed model reduces by 99%, 96% and 10%, respectively. The error variance reduces by 99%, 98% and 20%, respectively. The results indicate that this proposed algorithm can be simply operated with high precision and easy to realize in engineering.
    11  Numerical simulation on low calorific value coal-bed gascombustor and structural design optimization
    ZHANG Li WANG Jiong CAI Song
    2010, 33(12):65-71. DOI: 10.11835/j.issn.1000-582X.2010.12.011
    [Abstract](1630) [HTML](0) [PDF 7.55 M](1085)
    Abstract:
    This paper conducts the full size three-dimensional combustion numerical simulation study on the low-calorific value coal bed gas combustor. It explors the effects of different ratios of swirling wind and straight wind on flow field,temperature field and concentration field when this combustor combusts coal bed gas which methane volume concentration is 30 percent. The optimal ratio of swirling wind and straight wind is gained. Based on this,the number and obliquity of cyclone vane in gas pipeline are further optimized. The results show that when ratio of straight wind is 80 percent and ratio of swirling wind is 20 percent,the good jet flow rigidity is not only possessed,but also the strong spin momentum is brought. Reverse axial velocity grads and reverse velocity in central backflow region are also big,the burning temperature and combustion efficiency are high,and high-temperature region is diffusely distributed. When the number and obliquity of cyclone vane are respective 6 and 60,the mass fraction of methane descends quickly,the mass fraction of methane is low in outlet of combustion region,and the combustion efficiency is high.
    12  Analysis of ultimate load and mechanismsof failure in large cast steel joints
    LU Yun-xiang CAI Yuan-qi LI Ming-fang LIAO Feng-lian
    2010, 33(12):71-77. DOI: 10.11835/j.issn.1000-582X.2010.12.012
    [Abstract](1684) [HTML](0) [PDF 6.76 M](1136)
    Abstract:
    Based on a project of pipe truss roof framing in Chengdu, the ultimate limit state analysis is performed on cast steel joints by using FEM, in which Linear hardening elastic-plastic constitutive model is considered. The results show that, the joint has a great accumulation of plastic strain in ultimate loads, and the point of maximum stress is different from that in elastic with the development of the yielding zone. The paper propoes to use rate-type tensor for the large strain geometric nonlinear problem, shows the criterion of failure formation , and indicates that its essential to apply limit state analysis to the determination of the weakest location on cast steel joint design, which provides basis for understanding the failure modes and failure mechanism of cast steel joint and the cast steel joint design.
    13  The improved geometrical constraint model of open-pit mine boundary optimum and its application
    HUANG Jun-xin WANG Li-guan BI-Lin TAN Zheng-hua CHEN Jian-hong
    2010, 33(12):78-83. DOI: 10.11835/j.issn.1000-582X.2010.12.013
    [Abstract](1932) [HTML](0) [PDF 7.55 M](1255)
    Abstract:
    This paper develops the improved geometric constraint model (IGCM) based on the 3D block model. The variable-slope excavation cones of each block have been abstracted to collections of nodes and directed edges, and the optimization method has been introduced using the set theory. The IGCM consists of the optimized collection nodes and directed edges. The algorithm based on IGCM has been actualized in DIMINE digital mine system, and is applied to an actual open pit mine boundary optimization engineering. The results shows that IGCM can accurately simulate variable slope angles in any azimuth and elevation changes, and adapt to all open pit mine boundary optimum problems in any complex geological conditions, calculation speed and accurate. It provides a new and effective method for the variable-slope open pit mine boundary optimization problem in complex geological conditions.
    14  Real-time measurement of the prompt neutron decayconstant based on 252Cf source
    MI De-ling TANG Yue-lin WEI Biao REN Yong FENG Peng JIN Jing
    2010, 33(12):84-87. DOI: 10.11835/j.issn.1000-582X.2010.12.014
    [Abstract](2053) [HTML](0) [PDF 4.03 M](1334)
    Abstract:
    Prompt neutron decay constant is a key parameter in neutron action. Due to the real-time measurement demand for prompt neutron decay constant, a measurement method for prompt neutron decay constant is developed based on 252Cf Source and neutron pulse frequency spectrum measurement system. Triggered and initiated by 252Cf random neutron source, the pulse from detector is acquired and real-time converted to multi-channel data up to 1 GHz sample rate. The prompt decay constant can be acquired by utilize least squares of single exponential fitting to prompt decay curve based on prompt decay spectrum. The experimental result shows that prompt decay constant is 1.033μs-1 and the proposed method is a novel method for real-time measurement of prompt neutron decay constant.
    15  Analysis on dynamic response and influential factors ofmagneto-rheological damper for automotive suspension
    ZHANG Hong-hui TONG Jing XU Hai-peng
    2010, 33(12):88-94. DOI: 10.11835/j.issn.1000-582X.2010.12.015
    [Abstract](1736) [HTML](0) [PDF 7.27 M](1263)
    Abstract:
    Dynamic response is extremely important for Magneto-rheological (MR) damper, and directly affects the MR damper performance in semi-active control system. The dynamic responses for driver, damper and the whole controlled system are discerned, and the research contents and directions of dynamic response of MR dampers are also indicated. Based on the operation characteristics of MR dampers for automotive suspension, a reasonable description of dynamic response is proposed, and some important issues for dynamic response testing are discussed. Finally, the influence factors upon the response time of the MR dampers are investigated, and the directions for further improvement are given.
    16  A new boundary treatment of lattice boltzmann method (LBM) for fully developed pressure-driven periodic incompressible fluid flow
    LIAO Quan LI Long-jian CUI Wen-zhi
    2010, 33(12):95-102. DOI: 10.11835/j.issn.1000-582X.2010.12.016
    [Abstract](3098) [HTML](0) [PDF 7.64 M](2061)
    Abstract:
    This paper proposeds a new boundary treatment of Lattice Boltzmann Method (LBM) for fully developed pressure-driven periodic incompressible fluid flow. The pressure gradient, instead of equivalent body force, is applied to determine the particle distribution function on the periodic traverse sections for the fully developed pressure-driven periodic flow. Numerical simulations, including 2D pressure-driven poiseuille flow and fluid flow passing periodic square obstacles, are carried out using this new boundary treatment. Simulation results show that the proposed approach not only overcomes the nonphysical inlet and outlet flow disturbances (which the LBM simulation always suffers from using the existing pressure boundary methods), but also preserves the system periodicity and generates consistent pressure distribution with macroscopic periodic boundary conditions for the pressure-driven incompressible fluid flow.
    17  Hybrid distributed model predictive control using dynamic cooperation
    WEI Shan-bi HU You-qiang CHAI Yi DING Bao-cang
    2010, 33(12):103-108. DOI: 10.11835/j.issn.1000-582X.2010.12.017
    [Abstract](1756) [HTML](0) [PDF 5.34 M](1032)
    Abstract:
    For complex cooperative control problem of multi-agent systems, a distributed model predictive control scheme based on the dynamic cooperative rules is proposed. The collision avoidance constraint is transformed into hybrid rules based on the positions, and the Boolean function term was introduced in the cost function. In order to accommodate the complex time-varying environment, at each sample moment, the dynamic cooperative rules are designed according to the relative positions among the agents and the relative distances between the agents and the destination, so as to determine the weights in the Boolean function. This scheme reinforces consistencies of motion direction and control action, and improves stability and feasibility of distributed predictive control. As the control target can be achieved via a small prediction horizon, this scheme also enhances the real-time ability and practicality of distributed model predictive control. Simulation examples are given to illustrate the effectiveness of the proposed scheme.
    18  A clustering algorithm based on link availability for MANET
    FENG Wen-jiang WU Di
    2010, 33(12):109-113. DOI: 10.11835/j.issn.1000-582X.2010.12.018
    [Abstract](1808) [HTML](0) [PDF 4.40 M](1149)
    Abstract:
    The cluster topology management in the MANET network is studied in. The classic Lin-Gerla clustering algorithm is improved to increase the logical topological stability. By considering the node mobility in the communication systems, the notion of relative motion is introduced, and the nodes more stable are chosen as the cluster-heads, which effectively increases the stability of mobile network with Random Direction Model. Regarding the possible high concentration, a fast cluster splitting method is proposed for cluster maintenance. The simulation and performance analysis for the improved algorithm are given.
    19  Planar monopole antenna based on the fringe structure of coplanar waveguide
    DENG Chao XIE Yong-jun
    2010, 33(12):114-118. DOI: 10.11835/j.issn.1000-582X.2010.12.019
    [Abstract](1763) [HTML](0) [PDF 4.38 M](1529)
    Abstract:
    Coplanar waveguide possesses the advantage of lower loss and being easier to be integrated with other circuits comparing with the microstrip line. However, the bandwidth of the fed rectangular monopole antenna of the conventional coplanar is narrow. To broaden the bandwidth, the patch is notched on the bottom, and the central strip of the coplanar waveguide is prolonged to the groove top for feed. Both of the edges of a part of the coplanar ground and the groove top followed gradual regularity, and a ladder configuration is inserted into the groove to adjust the input impedance. Simulation indicates that the fractional bandwidths of the antennas can be broadened from 84.8% to 167.2%(a coverage of 2.17~24.3 GHz,S11≤-10 dB)in this way. The measured results agree well with the simulated ones. The radiation pattern of the antenna is nearly omnidirectional, which can be used in portable UWB communication systems.〖JP〗
    20  A new integrating forecast and its application in short-term climate prediction〖JP〗
    LI Xue-ming GUO Shang-kun WANG Jian-ke GAO Yang-hua
    2010, 33(12):119-126. DOI: 10.11835/j.issn.1000-582X.2010.12.020
    [Abstract](2041) [HTML](0) [PDF 6.73 M](1125)
    Abstract:
    The existing problems of the traditional weight integrating forecast methods and the application in climate prediction are analyzed. A new method based on data mining is presented, which uses BP artificial neural network to build the integrating forecast classifier to integrate the forecast results of sub-methods. According to the features of different forecast objects, this method can change weight dynamically, which overcomes the shortage of the traditional weight integrating forecasts that cannot change weight after been decided and overcomes the shortage that cannot get the optimal results. By predicting the precipitation and average temperature of Chengkou County in January, and spring drought index of Chongqing from 2001 to 2007, the experiment results show that the reliability and accuracy of the proposed model are better than those of the sub-methods and other integrating forecast methods, which proves the effectiveness of this method.
    21  A fast scanning method for deep-space exploration antennas〖JP〗
    CAO Hai-lin YANG Li-sheng TAN Xiao-heng YANG Shi-zhong
    2010, 33(12):127-132. DOI: 10.11835/j.issn.1000-582X.2010.12.021
    [Abstract](2108) [HTML](0) [PDF 5.44 M](1131)
    Abstract:
    A hybrid multi-beam spiral scanning method for deep-space exploration antennas is proposed, which can be used to estimate the true spacecraft position. Physical optics is used to compute and analyze the far-field pattern of the antenna for excitation of each of the individual array elements. The utilization of a focal-plane array in place of a standard single-mode feed improves the field of view of large high-frequency antenna. Multiple closely overlapping beams are synthesis with conjugate field matching technique. Results show that, combined with spiral scanning method, the multiple beams reflector antenna can reduce the scanning time by one third, and the array gain in multi-beam reflector antenna can improve the distance of deep-space exploration.
    22  Improved CMI code in passive induction setting system 〖JP〗
    LIU Xiao-min XIONG Dong ZHU Zhou-xian YANG Xue-min WANG Feng
    2010, 33(12):133-137. DOI: 10.11835/j.issn.1000-582X.2010.12.022
    [Abstract](1609) [HTML](0) [PDF 4.49 M](1078)
    Abstract:
    Aiming at the low energy transmission efficiency of the passive induction setting system with the existing codes, an improved CMI code is proposed as baseband code by changing the equivalent average time of high level during a code cycle under 2ASK modulation. The properties are analyzed, such as energy transmission efficiency, power spectrum and the error probability in incoherent demodulation in AWGN channel. The code is successfully applied to passive induction setting system, and the decoding method and measured voltage waveform are given. With the code, the energy transfer efficiency is improved by 60% than that of CMI code. It is not only beneficial to energy transmission, but also has the merit of CMI code that the bit timing information is extracted easily, which is fully utilized in incoherent demodulation to solve the sampling moment error accumulation problem resulted from the instability of internal oscillator.
    23  Bamboo simulation based on fractal algorithm
    LUO Yan WU Zhong-fu GUO Xuan-chang WU Gang
    2010, 33(12):138-144. DOI: 10.11835/j.issn.1000-582X.2010.12.023
    [Abstract](1853) [HTML](0) [PDF 7.02 M](1371)
    Abstract:
    Fractal theories are quite popular in modeling and simulation of objects with irregular shapes. The combination of fractal theories and virtual reality technologies may be used to generate the realistic and complex nature objects. Plants simulation is one of the most important fields in computer graphics. The simulation algorithms of Bamboo are discussed. The conventional L-system modeling approach is improved based on the single-axis characteristics of Bamboo, and the relevant method, e.g. the displacement mapping technique used in Bamboo internodes modeling and rendering is discussed as well. Moreover, based on the basic idea of particle system, an improved simulation approach for distribution pattern of Bamboo is presented.This improved simulation algorithm can make the random distribution of particles break the rules of rectangular shape. Simulation results show that the proposed methods can simulate realistic Bamboo forms and distribution patterns in the nature.

    Current Issue


    Volume , No.

    Table of Contents

    Archive

    Volume

    Issue

    Most Read

    Most Cited

    Most Downloaded