Volume 41,Issue 5,2018 Table of Contents

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  • 1  Reliability evaluation of distribution system with recloser feeder automation
    ZHAO Yuan WU Lin LIU Qingyao LIU Ziya LIANG Yan CHEN Guo
    2018, 41(5):1-14. DOI: 10.11835/j.issn.1000-582X.2018.05.001
    [Abstract](964) [HTML](345) [PDF 579.51 K](993)
    Abstract:
    Feeder automation (FA) based on recloser could improve the reliability of distribution network effectively. Therefore, it's important to quantatively analyze the impact of reclosing FA on the reliability of distribution system. Firstly, all load zone types are re-divided based on distribution network partition in this paper. Then according to the probability model and the control logic of reclosing FA, the probability and the time for automatic load restoration are derived based on detailed analysis of various outage modes and failure effect of sectionalizer in each stage of power service restoration. Finally, the formulas of reliability indices of distribution network with recloser feeder automation are achieved. The correctness and effectiveness of the proposed model are verified by examples.
    2  Application of Bayesian predictive bee colony algorithm in WSN optimization
    FU Guangjie HU Mingzhe
    2018, 41(5):15-22. DOI: 10.11835/ji.ssn.1000-582X.2018.05.002
    [Abstract](997) [HTML](513) [PDF 4.50 M](1000)
    Abstract:
    The node distribution of wireless sensor network(WSN) is often unreasonable, and always has many monitoring blind spots.Aiming at this problem,Bayesian predictive artificial bee colony algorithm (BPABC) is proposed to develop a node distribution scheme. Based on the idea of Bayesian prediction algorithm, this algorithm predicts the probability of optimal solution of each nectar source in the bee colony algorithm, and guides the followed bees to seek optimal solution. A designed algorithm is used to optimize the distribution of nodes in WSN, and the effect is compared with those of artificial bee colony algorithm and global artificial bee colony algorithm. The results show that BPABC is superior to the other two algorithms in terms of average coverage and worst coverage. Besides,this algorithm also has obvious advantages in iterative convergence rate. In order to further verify the practicability of the improved algorithm, this paper uses BPABC algorithm to develop WSN node distribution scheme for different monitoring areas. Coverage for all WSNs is around 97% with a standard deviation no more than 0.005% can be seen that the WSN node distribution optimization scheme based on BPABC has high coverage,good adaptability and stability.
    3  Actuating equation of macro-fiber composite on arc-plate structures
    TU Jianwei HUANG Qianwen ZHANG Jiarui LUO Wei LAI Fangpeng
    2018, 41(5):23-29. DOI: 10.11835/j.issn.1000-582X.2018.05.003
    [Abstract](904) [HTML](434) [PDF 916.79 K](1042)
    Abstract:
    In order to obtain accurate actuating force and actuating moment of MFC(macro fiber composite) on arc-plate structures and improve the vibration control effect of MFC, we present a calculation method of MFC arc-plate structure actuating equation. On the basis of the first kind of piezoelectric basic equations, considering the compound effect between MFC and the controlled structure and the influence of arc-plane structure curvature on MFC, we establish the P1-type MFC coupled-plate structure actuating equation and obtain the actuating force and actuating moment of MFC on arc-plate structure. By comparing the model's results with the official data, it's found the deviation is less than 4%. The vibration control experiment of MFC coupled-plate structure is completed, and the deviation between the simulation results and the experimental results is less than 8.5%, which indicates that the P1-type MFC actuating equation is correct. The P1-type MFC actuating equation can be used in the simulation calculation of vibration control for the MFC arc-plate structure.
    4  The instability of a fluid-supported inhomogeneous film: A mechanical viewpoint
    ZHANG Zhengcai ZHANG Mangong NING Youjun WU Tao NING Huiming GU Bin JIA Fei
    2018, 41(5):30-36. DOI: 10.11835/j.issn.1000-582X.2018.05.004
    [Abstract](1112) [HTML](393) [PDF 1.37 M](1316)
    Abstract:
    The system with a film supported by fluid substrate can be widely found in nature and has important applications in engineering fields such as functional surface preparation. This work focuses on the instability mechanism of a fluid-supported inhomogeneous film, and establishes the relationship between geometric and material inhomogeneity and film instability mode. The effects of the length, position and elastic modulus of the defect on the evolution of the film surface instability morphology are studied by numerical simulation. Experiments of the instability of polyester film with prefabricated defects on the water surface are realized by self-designed devices, and the experimental results show that the instability morphology is consistent with the numerical simulation results. By pre-coating the uncured molding gel on the film, the molding gel can copy the instability morphology to form a mold. This work provides not only guidance for the optimal design of the fluid-supported film instability morphology, but also an approach for the preparation of films with specified special morphologies.
    5  Development and data analysis of real vehicle data test bench for automobile LCD instrument
    GUO Jianzhong WU Jianli XIE Bin CHENG Feng TANG Hualiang
    2018, 41(5):37-43. DOI: 10.11835/j.issn.1000-582X.2018.05.005
    [Abstract](997) [HTML](420) [PDF 1.54 M](1344)
    Abstract:
    In order to realize the full function test and display strategy verification of the automobile instrument, a simulation test environment is built by using the actual vehicle data. The host computer reads the real data script, and the serial data are sent to the electronic control unit, and then the electronic control unit controls instrument signal to realize instrument function test. The stepper motor is used to drive the sliding rheostat to simulate the oil fuel consumption value of the oil float and realize the simulation of the actual fuel quantity data. Based on win32 platform development data analysis environment, the actual vehicle data extraction analysis is realized to provide data basis for the instrumentation control strategy and display algorithm. A common script protocol is developed according to the source to meet a variety of instrument specifications test requirements. A variety of instrumentation tests show the platform has a good practicality, versatility, and can greatly shorten the LCD instrument research, development and testing cycle.
    6  A bulk ablation model considering insulator expansion phenomenon
    WANG Shuxian XU Yihua
    2018, 41(5):44-51. DOI: 10.11835/j.issn.1000-582X.2018.05.006
    [Abstract](979) [HTML](812) [PDF 898.53 K](1034)
    Abstract:
    According to the experimental phenomenon that carbon layer thickness is greater than the insulator matrix loss thickness, a bulk ablation model considering insulator expansion phenomenon with double regions is established. It's believed that expansion is produced during pyrolysis process and the formation rate of carbon layer is 2 times faster than the lapse rate of matrix. At each time step, the interface position of carbon layer and the matrix is determined according to the relationship between local temperature and insulator pyrolysis temperature, and the method of remeshing and data exchange coupling calculation are developed at the same time. The ablation rate and carbon layer porous structure obtained by the double regions bulk ablation model agree well with the experimental results, which proves that the model can basically describe the ablation details of EPDM(ethylene-propylene-diene monomer) insulator.
    7  Analysis of ultra-low ripple PWM coding technique
    RAN Duogang CHEN Peng LIU Weiling XU Yahao
    2018, 41(5):52-59. DOI: 10.11835/j.issn.1000-582X.2018.05.007
    [Abstract](951) [HTML](426) [PDF 441.30 K](810)
    Abstract:
    Traditional pulse width modulation (PWM) produces harmful ripple, which will interfere with other circuits. It is very unfavorable for many applications where high accuracy is required. A digital PWM scheme based on code technique is proposed and it can significantly reduce the ripple. The scheme can be expressed as:the PWM pulse sequences are evenly distributed throughout the PWM cycle. The most ideal situation is up to a single pulse level. Theoretically, there is a strong positive correlation between the output ripple and the amplitude of each harmonic of the signal, in which the ripple generated by fundamental and the second harmonic wave is the most significant. More deep analysis shows that with the scheme based on code technique, the ripple can be reduced to the minimum order of digital PWM. Preliminary experiments show that the technique is useful.
    8  A numerical manifold method coupling multiple types of manifold covers and its applications
    WU Xin GUO Xuan KANG Ge NING Youjun
    2018, 41(5):60-67. DOI: 10.11835/j.issn.1000-582X.2018.05.008
    [Abstract](1011) [HTML](674) [PDF 6.10 M](1512)
    Abstract:
    To better use the numerical manifold method (NMM) to simulate complex continuous and discontinuous deformation problems, for the flexibility of the choice of mathematical covers in the NMM, we adopt the finite element mesh to generate NMM mathematical covers so as to avoid the appearance of too-small manifold elements, and put forward an independent cover method, in which a single material domain is described as one manifold element. Different cover types are coupled in the simulations of the tensile and compressive concrete meso-scale models, as well as a rock slope model with complex structures. The corresponding mechanical deformation and failure processes are well reproduced by NMM simulations. The coupling use of different cover types makes the generated NMM simulation models more reasonable. The independent cover method decreases the complexity to construct NMM simulation models for discrete systems, and reduces the numbers of manifold elements and the contact numbers along discontinuity surfaces, which helps to improve the NMM computational efficiency.
    9  Measuring angular deflections of PMMA by high-precision digital gradient sensing method
    CHEN Dedeng ZHANG Rui GUO Ran
    2018, 41(5):68-75. DOI: 10.11835/j.issn.1000-582X.2018.05.009
    [Abstract](940) [HTML](498) [PDF 1.96 M](1163)
    Abstract:
    Stress gradient (angle deflection) of polymethyl methacrylate (PMMA) plate is measured by digital gradient sensing method(DGS). DGS first uses the digital image correlation method (DIC) to measure the full field displacements in the region of stress concentration of PMMA plate under the three-point bending. Then, angular deflection of light rays can be linked to stress gradients of PMMA plate according to the photo-elastic effect, and the angular deflections of PMMA plate can be further obtained. The angle deflections that are measured directly are compared with the analysis data, and errors are found. Because the in-plane motion of the rigid body and the out-of-plane motion exist unavoidably in the test, so the error of the angle deflections appears. After removing the above influencing factors by compensation regional method, we discuss the influence of the in-plane motion of the rigid body and the out-of-plane motion on the test. Finally compared with the analytic value, the results show that the compensation regional method reduces the measurement error, and the high-precision angular deflections are obtained. The average relative error of angular deflections in the x and y directions are 4.90% and 5.89%, respectively.
    10  Adsorption property on Pb(Ⅱ) of bentonite modified by chitosan/hydroxy-lanthanum
    BIAN Lingtao ZHANG Lianke LI Haipeng GAO Yanhong
    2018, 41(5):76-84. DOI: 10.11835/j.issn.1000-582X.2018.05.010
    [Abstract](893) [HTML](542) [PDF 1.06 M](1062)
    Abstract:
    To improve adsorption effect of Na-bentonite on Pb(Ⅱ), chitosan/hydroxy-lanthanum complex pillared bentonite (GZ-P) is prepared by hydrothermal synthesis method using Na-Bentonite modified with the mixture of chitosan and hydroxy-lanthanum cation as pillared agent. The properties of GZ-P are characterized by X-ray diffraction (XRD), Fourier transform infrared spectrum (FTIR), scanning electron microscopy (SEM) and other analytical methods. And the adsorption property of Pb(Ⅱ) by GZ-P is discussed. The results show that the mixture of chitosan and hyroxy-lanthanum cation intercalates into bentonite and plays the role of pillar. The particles become fuller and denser. Surface voids and roughness increases. Removal rate and adsorption capacity of Pb(Ⅱ) by GZ-P increase first and then decrease, and increase again with the increase of PH value when the temperature is 25℃ and reaction time is 120 min. The highest removal rate reached to 98.93% and the maximum Pb2+ adsorption capacity is 33.67 mg/g when initial pH is 4. The least adsorption capacity is found when pH is 6. However, the removal rate is more than 85% even under that condition. Langmuir equation could better imitate the adsorption isothermal process of GZ-P to Pb(Ⅱ), and the adsorption process could be fitted by the pseudo-second order model, which indicates that Pb(Ⅱ) ions are adsorbed onto GZ-P by chemical interactions via monolayer.
    11  Fine-grained image classification based on Xception
    ZHANG Qian SANG Jun WU Weiqun WU Zhongyuan XIANG Hong CAI Bin
    2018, 41(5):85-91. DOI: 10.11835/j.issn.1000-582X.2018.05.011
    [Abstract](1305) [HTML](788) [PDF 622.94 K](1292)
    Abstract:
    Fine-grained image classification is a more detailed division of the sub-categories of traditional image classification, which achieves a more sophisticated identification of objects. And it is a very challenging research in the field of computer vision. By analyzing the existing fine-grained image classification algorithm and Xception model, we propose to apply the Xception model to the fine-grained image classification task. Initialization of convolution layers uses pre-training model parameters of ImageNet classification. Then we resize images, transform data type, normalize value, and randomly initialize classifier. Finally, the network is fine-tuned. Our method obtains 71.0%, 89.9% and 91.4% per-image accuracy on the CUB200-2011, Flower102 and Stanford Dogs dataset respectively. The experimental results show that the Xception model has good generalization ability in fine-grained image classification. Because it does not need additional annotation information such as object bounding box and part annotation, the Xception model has good versatility and robustness in fine-grained image classification.
    12  Joint supervision of center loss and softmax loss for face recognition
    YU Chengbo TIAN Tong XIONG Di'en XU Linying
    2018, 41(5):92-100. DOI: 10.11835/j.issn.1000-582X.2018.05.012
    [Abstract](1329) [HTML](619) [PDF 1.25 M](1169)
    Abstract:
    Nowadays, deep learning has made great achievements in face recognition. Most of the convolutional neural network uses the Softmax loss function to increase the distance between classes. However, adding samples of new classes will reduce the distance between classes and the performance of the network. In order to improve the recognition ability of the network characteristics, a face recognition approach based on joint supervision of center loss and Softmax loss is proposed. On the basis of Softmax, first of all, a class center is maintained in the feature space for each class of the training set. When a new sample is added to the training process, the network will constrain the distance of the classification center of the sample, and thus both intra-class aggregation and inter-class separation are considered. Secondly, the concept of momentum is introduced. When the classification center is updated, by retaining the previous update direction and using the gradient of the current batch to fine-tune the final update direction, the method can increase the stability and improve the learning efficiency of the network. Finally, the test experiments on the face recognition benchmark library LFW (labeled faces in the wild) prove that the proposed joint supervision algorithm achieves 99.31% of face recognition accuracy on a small network training set.

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