Volume 39,Issue 1,2016 Table of Contents

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  • 1  Control strategy and parameter optimization of hybrid energy storage device for electric vehicles
    HU Jianjun XIAO Jun YAN Jiujiang
    2016, 39(1):1-11. DOI: 10.11835/j.issn.1000-582X.2016.01.001
    [Abstract](1174) [HTML](307) [PDF 5.38 M](0)
    Abstract:
    We studied the energy storage device of an electric vehicle for solving the low specific-power problem of its battery. Considering the characteristics and the control target of a hybrid energy storage device, we developed a five-operation mode, and proposed a fuzzy control strategy based on the vehicle speed and current constraints. To further improve the vehicle performance and reduce the output current of the battery, we applied linear optimization to the parameter design of the device. Simulation results show that the use of the hybrid energy storage device reduces the acceleration time of the electric vehicle by 12%, increases the braking energy recovery efficiency by 39%, and reduces the 100 km energy consumption by 8.55%. Moreover, it greatly decreases the output current of the battery, and thus benefits the cycle life of the battery and extends the driving range.
    2  A gesture-recognition algorithm based on improved SVM
    WANG Jian CHEN Yi DENG Shuai
    2016, 39(1):12-17. DOI: 10.11835/j.issn.1000-582X.2016.01.002
    [Abstract](1441) [HTML](345) [PDF 2.06 M](0)
    Abstract:
    An improved action recognition method is proposed based on the signals acquired by a smart phone acceleration sensor to reduce the complexity of the traditional action recognition method and enhance the recognition rate. The blind selection method is applied in feature extraction stage, which means using principal component analysis (PCA) method to reduce dimensionality and eliminate multi-dimensional interference, while the selected features have no corresponding physical significance. In classification and identification, the genetic algorithm is used to optimize support vector machine (SVM) classifier. Experimental results indicate that the proposed method can accurately recognize actions such as walking, standing, running and climbing stairs.
    3  Wind-farm capacity-credit model considering transmission congestion
    GAN Ming XIE Kaigui HU Bo
    2016, 39(1):18-24. DOI: 10.11835/j.issn.1000-582X.2016.01.003
    [Abstract](1154) [HTML](362) [PDF 1.11 M](0)
    Abstract:
    Both reliability and transmission congestion should be considered when a wind farm is connected to a power system. Nevertheless, wind-farm capacity credit (CC) is defined currently considering reliability only. In this work, we proposed a wind-farm CC definition based on transmission congestion, built a CC model taking into account the random failures of power system components (generating units, transmission lines and transformers) using Monte Carlo technique, and proposed a solution algorithm of CC model using the bisection method. We also proposed wind power congestion indices to describe the contribution of a wind farm incorporated into a power system to alleviating transmission congestion. The case studies on a modified IEEE-RTS indicate that the proposed method is effective and feasible. The results show that for a power system, alleviation of transmission congestion is related to the wind-farm location, the combination of CC and wind power congestion indices can evaluate the effectiveness and economical efficiency of a wind farm in alleviating transmission congestion.
    4  A review on the on-line analysis of inter-turn short circuit faults in field winding of synchronous generators
    HAN Li OU Xianpeng GAO You ZHOU Guanghou
    2016, 39(1):25-31. DOI: 10.11835/j.issn.1000-582X.2016.01.004
    [Abstract](1348) [HTML](586) [PDF 1.01 M](0)
    Abstract:
    The inter-turn short circuit in field winding is one of the common faults of synchronous generators. To ensure the safe and reliable operation of the generator unit and the power grid, it is necessary to detect this kind of fault on-line. We firstly introduced the status quo of current research methods for the on-line detection of inter-turn short circuit faults in field winding of synchronous generators, including the magnetic-current harmonics analysis method, the probing coil method, the multi-loop method, the output electrical parameter analysis method and the vibration analysis method. These methods and their diagnostic effects were discussed and compared. Then, two new ideas for the output electrical parameter analysis method were provided and the developing tendency of on-line detection methods was forecasted. Finally, it was pointed out on-line analysis method should be practical and multi-functional.
    5  An early warning method of transmission line galloping based on Adaboost algorithm
    LI Zhe WANG Jian LIANG Yun XIONG Xiaofu WENG Shijie
    2016, 39(1):32-38,97. DOI: 10.11835/j.issn.1000-582X.2016.01.005
    [Abstract](1098) [HTML](377) [PDF 2.39 M](0)
    Abstract:
    Transmission line galloping is a worldwide problem which has not been fully understood, and it has seriously threatened the safe and stable operation of a transmission system. We investigated the factors of meteorological environment that influence galloping, and proposed an early warning method of transmission line galloping based on the Adaboost ensemble learning algorithm. In this method, the decision stump based on the Gini index is used as the weak classifier. The prediction result and its confidence are obtained by training and weighted summing of multiple weak classifiers, which are helpful information for the decision making of operators and dispatchers of power grids. The effectiveness of the proposed method is proved by the verification experiment with historical data.
    6  Determination of the nozzle aperture of a compressed natural gas injector in the conversion of a comressed natural gas vehicle
    BAO Weining PENG Cong LI Xuepeng
    2016, 39(1):39-47. DOI: 10.11835/j.issn.1000-582X.2016.01.006
    [Abstract](1771) [HTML](354) [PDF 2.30 M](0)
    Abstract:
    In the reifit process of a compressed natural gas (CNG) vehicle, the nozzle aperture of a CNG injector is an important process parameter and is difficult to determine. To improve the efficiency and accuracy of installation work, it is imperative to find a method for installers to quickly and accurately determine the required aperture. For this purpose, we analyzed a large volume of data obtained in actual refitting practices, and proposed a fuzzy pattern-recognition algorithm for determining the size of a nozzle aperture based on the engine power, the total mileage and the current mileage of spark plugs being used of the vehicle to be refitted. Verification of the algorithm in MATLAB finds that by using more random sampling and grouping and modifying the computing process of the algorithm, the accuracy of aperture recognition is improved significantly. The feasibility and accuracy of the algorithm are confirmed by comparison of the computed results with previous installation records.
    7  Soft sensor model for wood moisture content based on LS-SVM optimized by PSO
    JIANG Bin SUN Liping CAO Jun JI Zhongzhi
    2016, 39(1):48-54. DOI: 10.11835/j.issn.1000-582X.2016.01.007
    [Abstract](1250) [HTML](308) [PDF 2.48 M](0)
    Abstract:
    Wood moisture content is an important technical specification in the wood drying process. Considering the strong coupling, large lag non-linear features of the wood drying process and the problem of low precision of wood moisture content detection, we proposed a soft sensor method using least squares support vector machines (LS-SVM) to learn time series data of a non-linear system, and built a soft sensor model of the controlled object. We also used the particle swarm optimization (PSO) algorithm in the moving horizon optimization of the penalty factor and the kernel function parameter of LS-SVM to improve the prediction precision of the soft sensor model. Taking the inner temperature and humidity of a wood drying kiln as the sample data, the wood moisture content at a specific point can be detected with the model based on LS-SVM optimized by PSO, which is denoted by PSO-LSSVM. The simulation reveals that the PSO-LSSVM has a high prediction precision and strong generalization ability, and can fulfill the actual measurement demand of a wood drying control system.
    8  Modeling air-conditioning load forecasting based on adaptive weighted least squares support vector machine
    ZHAO Chao DAI Kuncheng
    2016, 39(1):55-64. DOI: 10.11835/j.issn.1000-582X.2016.01.008
    [Abstract](1202) [HTML](297) [PDF 2.56 M](0)
    Abstract:
    To improve the accuracy of building air-conditioning load prediction, we proposed an adaptive weighted least squares support vector machine (AWLS-SVM) algorithm based on analyzing the main related factors. This algorithm uses least squares support vector machine regression to develop the model and obtain the sample data fitting error, and calculates the initial weight according to the statistical characteristics of the prediction errors. The particle swarm optimization (PSO) is applied to obtain the optimal parameters of the AWLS-SVM, so as to improve its forecasting accuracy. Based on the simulated data from the DeST platform, we used the AWLS-SVM model to predict the hourly air-conditioning load of an office building in South China. The simulated results show that the AWLS-SVM has better accuracy compared with RBFNN model, LS-SVM model and WLS-SVM model, with a mean absolute error reduced by 51.84%, 13.95% and 3.24%, respectively. We also used the AWLS-SVM method to build a prediction model for the air-conditioning load of another office building based on real measurements. The results show that AWLS-SVM method outperform the other three models in terms of accumulated error, demonstrating that AWLS-SVM is effective for building air-conditioning load prediction.
    9  Effects of heat flow fluid-solid coupling on the characteristics of shale permeability
    LU Yiyu LIU Xiaochuan TANG Jiren HUANG Fei
    2016, 39(1):65-71. DOI: 10.11835/j.issn.1000-582X.2016.01.009
    [Abstract](1485) [HTML](350) [PDF 2.35 M](0)
    Abstract:
    To study the influences of geo-temperature on the seepage properties of a shale, we analyzed the temperature-dependent patterns of viscous force change of methane, the formations of a shale by heat stress and expansion, and the matrix shrinkage caused by methane desorption. By using shale samples of Longmaxi Formation in Youyang of Southeast Chongqing, we conducted an experiment on the temperature dependence of the seepage of shale rock. The experiment shows that an increase in temperature leads to an increased viscous force of methane and reduced flow speed. The differences in expansion of clay minerals and organic matters produce thermal stress and compress the shale skeleton, and matrix thermal expansion reduces the substrate gaps, both leading to a decrease in the seepage channels. The matrix shrinkage has very little influence on the infiltration capacity of pores and cracks. The major effects of temperature on the seepage characteristics of shale are the decrease of flow speed of methane due to increased viscous force and compressed seepage channels due to thermal stress and thermal expansion.
    10  Hydraulic fracturing technology by drilling through strata for outburst prevention in coal roadway strips and its application
    YUAN Zhigang REN Meiqing SHENG Yonghong WANG Hongtu
    2016, 39(1):72-78. DOI: 10.11835/j.issn.1000-582X.2016.01.010
    [Abstract](1200) [HTML](296) [PDF 2.78 M](0)
    Abstract:
    To realize regional gas control in a low permeability coal roadway strip, based on the features of high pressure water, we proposed a hydraulic fracturing technology of drilling through strata in coal roadway strip to prevent outburst by applying the elastic theory. We built a calculation model for coal seam initiation pressure is established, developed a device to export flow rates and pressure, and applied them to an industrial experiment. The experiment results show that concentration and quantity curves of gas drainage in fracturing borehole exhibit characteristics of "high-low-high", which reflects the dual role of hydraulic fracturing. Gas quantity in fracturing boreholes is 20 times and 133 times of those of hydraulic cutting boreholes and ordinary crossing boreholes, respectively. When residual gas content of a coal roadway strip is reduced to 8 m3/t, the elimination effect of the hydraulic fracturing technology of drilling through strata is outstanding.
    11  Deterioration of reinforced-concrete bond strength due to corrosion
    CHEN Zhaohui TAN Dongyang ZENG Yu LIN Wenxiu
    2016, 39(1):79-87. DOI: 10.11835/j.issn.1000-582X.2016.01.011
    [Abstract](1354) [HTML](557) [PDF 3.36 M](0)
    Abstract:
    The environment-induced corrosion of steel bars in concrete results in deterioration of reinforcement-concrete bond properties, and causes the damage of concrete structures. The accelerated corrosion of reinforced concrete specimens and also the pull-out test of the corroded specimens were carried out to study the deterioration of corroded reinforced-concrete bond strength. We used industrial computed tomography (ICT) scanning to exam the cracking of the concrete cover of the specimens caused by corrosion. According to the pullout tests, the ultimate shear capacity and the corresponding displacement of the corroded specimens are degraded with the corrosion extent, and the bond stiffness is depressed. The analysis based on the experimental results shows that the thickness of corrosion products, other than the corrosion ration of steel bars, influences the corroded expansion force and the degradation of bond strength more directly. By introducing the factors of the thickness of corrosion, the ratio of thickness of concrete coat to the steel bar's diameter, and the tension strength of concrete, a bond strength model of corrosion reinforced-concrete is proposed. The practicability of the suggested model is proved by experimental data.
    12  Bridge local scour monitoring using magnetic label rock
    JIANG Shenghua WU Liqun HOU Jianguo He Yingming
    2016, 39(1):88-97. DOI: 10.11835/j.issn.1000-582X.2016.01.012
    [Abstract](1302) [HTML](309) [PDF 4.06 M](0)
    Abstract:
    The bridge local scour monitoring is characterized by adverse environment with great danger which makes sensor arrangement very difficult. So, we proposed using magnetic label rock as a dynamic scour sensor for bridge scour monitoring. The monitoring system consists of magnetic label rock and magnetic gradiometer. The magnetic label is casted into concrete to construct a magnetic label rock. The degree of freedom is reduced to solve the nonlinear and ill-posed problems in the magnetic reversion by means of optimization search. In the experimental verification for localization of magnetic label rock, the maximum error and relative error for localization is about 0.2 m and 5% respectively, which satisfies the requirement in the bridge local scour monitoring. The magnetic gradient, invariants and magnitude are all highly correlated with scour displacement, which can be directly used for early warning in the bridge local scour monitoring.
    13  Drivers' adaptation luminance changing rule when driving into tunnels
    HU Yingkui CHEN Zhonglin ZHANG Qingwen WEN Ji HUANG Ke
    2016, 39(1):98-104. DOI: 10.11835/j.issn.1000-582X.2016.01.013
    [Abstract](1265) [HTML](341) [PDF 3.48 M](0)
    Abstract:
    Drivers' adaptation luminance changes with the changing of the sense within their visual field when they drive into tunnels. Tunnel lighting design should provide brightness levels in accord with drivers' visual adaptation; so, it is necessary to find out drivers' adaptation luminance changing rule when driving into tunnels. For this purpose, we took four tunnels as the research objects, and measured and calculated drivers' adaptation luminance at different positions within a stopping sight distance to the tunnel entrances. The results indicate that drivers' adaptation luminance changing rule is similar when they drive into the same tunnel at different time. Drivers' adaptation luminance decreases gradually when they drive into tunnels, but the decrease is nonlinear, and drivers' adaptation luminance decreases fast when they are in the distance of 20 m to30 m from the entrance of a tunnel.
    14  Determination of energy consumption benchmark of campus buildings in China
    ZHU Neng ZHU Tianli TONG Dingding YUAN Tianhao WANG Zhaoxia
    2016, 39(1):105-112. DOI: 10.11835/j.issn.1000-582X.2016.01.014
    [Abstract](1370) [HTML](287) [PDF 2.84 M](0)
    Abstract:
    With the rapid growth of the campus building area, energy consumption of campus buildings has taken up a large portion in social energy consumption. To facilitate the construction management of economical campuses, we calculated and systematically researched of campus building energy consumption benchmarks using the theoretical methodology of building energy consumption baselines. We collected a great volume of energy consumption data, and used the SPSS statistical software to research on classification of campus construction. We proposed a method of classifying public teaching buildings based on their functions and air conditioning systems. Then, we calculated the energy consumption baseline of campus buildings using the quartile method. Finally, we obtained three kinds of baselines about low, average and high level energy consumption, respectively, and also put forward a correction method for these building energy consumption baselines.
    15  Mechanical analysis of underground dynamic disasters induced by thrust faults of an arc fault plane
    LYU Jinguo JIANG Yaodong NAN Cunquan CUI Naixin WANG Kaixing
    2016, 39(1):113-119. DOI: 10.11835/j.issn.1000-582X.2016.01.015
    [Abstract](1326) [HTML](251) [PDF 3.10 M](0)
    Abstract:
    To discover the mechanism of underground dynamic disasters close to thrust faults of an arc fault plane, a simplified mechanical model of arc fault planes under the influence of horizontal tectonic stress is constructed. The distribution laws of both horizontal tectonic stress and additional vertical stress induced by the tectonic stress are acquired, and then a mathematical model of the critical angle of thrust-shear slide of hanging wall is set up. The study results show that both horizontal tectonic stress and additional vertical stress increase with the increase of a fault dip. When the dip angle is close to 90°, the additional vertical stress increases rapidly, and its maximum is several times higher than the tectonic stress. The critical angle of the fault thrust sliding is calculated based on mechanical analysis, and this is hoped to provide some reference for the early warning dynamic disasters about coal and rock.
    16  An assessment method for automobile exhaust based on three-dimensional spectrogram features
    LUO Dechao LUI Guoping LIU Jun XIANG Fei YUAN Quan ZHANG Shunxing
    2016, 39(1):120-126. DOI: 10.11835/j.issn.1000-582X.2016.01.016
    [Abstract](1010) [HTML](289) [PDF 3.86 M](0)
    Abstract:
    We present an assessment method of automobile exhaust using three-dimensional spectrogram features to solve the nonlinear and time-varying problems of automobile exhaust emissions. The method takes advantage of spectral analysis to obtain the three-dimensional spectrogram features of automobile exhaust. These three-dimensional spectrogram features, being considered as the input variables, are fed to radial basis function neural network (RBFNN) adapting the K-means algorithm. After completing the training of RBFNN, the three-dimensional spectrograms, being unseen by the network before, are fed to the well-trained network for testing, which achieves the assessment level of automobile exhaust via the classification of three-dimensional spectrogram features. The numerical experiments indicate that the proposed method has a high accuracy.

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