Table of Content

28 December 2013, Volume 47 Issue 12 Previous Issue    Next Issue

Automation Technique, Computer Technology

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A Rendering Method for Point-Based Surfaces with Sharp Features DAI Chunfeng,GU Lixu 2013, 47 (12):  1813-1817.  Abstract ( 945 )   Save The splatting algorithm has difficulty in rendering sharp features. To solve this problem, the point-and-edge model was used and improved. A novel clipping algorithm, which used a ray-based method to decide the relative position between points and clipping areas, was proposed. This algorithm could handle various clipping, reduce the restrictions on the sampling rate of surface points caused by the boundery of the surface, avoid a complicated upsampling preprocessing step and simplify the rendering of the model. A comparison of different models indicates that the rendering speed is mainly affected by the average clipping edges of every point.   References | Related Articles | Metrics

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Contour Extraction and Fault Detection of Insulator Strings in Aerial Images FANG Ting,DONG Chong,HU Xingliu,WANG Yan 2013, 47 (12):  1818-1822.  Abstract ( 1206 )   Save Based on the fact that insulator bursting and missing are threats to the safety of electric power, this paper proposed an algorithm to detect fault by calculating the number of insulators. Because of the fixed number of insulators, an image processing method was adopted to detect the fault of insulators by calculating the number of insulators, which can be applied to intelligence patrol system. Otsu and morphological filtering were used to preprocess the image, the immune genetic snake algorithm was adopted to optimize insulator concavity regions to get a complete contour of the insulator strings, and the ellipse fitting and connected region algorithm were used to calculate the number of string of insulators. The proposed algorithm can extract the initial contour of insulator strings effectively and calculate the number of insulators, establishing a good foundation for further study of insulator fault detection.   References | Related Articles | Metrics

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Simulation of Spot Weld Failure Based on KSII Test LI Meng,MAO Bowen,WANG Wurong,WEI Xicheng 2013, 47 (12):  1823-1827.  Abstract ( 1539 )   Save Based on the 8-Hex spotweld model, the spotweld failure during coupon test was simulated. A kind of testing equipment was designed for KSII spotweld specimen tension. This equipment was utilized to conduct KSII0° and KSII90° experiments, which can determine the spotweld failure force. The difference between KSII0° test and lapshear test in measuring spotweld tensile shear strength was compared and discussed. Based on the simulation and test results of KSII0°, Young’s modulus and Hardening modulus in spotweld materials properties was determined. The front rail crush test was simulated with the spotweld failure model based on the KSII test. The experiment and simulation results show that the KSII spotweld failure model has an excellent accuracy.   References | Related Articles | Metrics

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Star Image Adaptive Clutter Suppression Using Kernel Rayleigh Quotient Quadratic Correlation Filter GUO Jingming1,2,HE Xin1,YANG Jie3,WEI Zhonghui1 2013, 47 (12):  1828-1835.  Abstract ( 896 )   Save In order to detect small star point targets in star images, an adaptive clutter suppression algorithm based on kernel Rayleigh quotient quadratic correlation filter was proposed. The star image simulation method was adopted to generate optical axis point randomly, produce training samples according to the twodimensional Gaussian model,  extract improved speed-up robust features(SURF), and learn to build kernel Rayleigh quotient quadratic correlation filter(KRQQCF). In order to detect the target quickly, for the image to be detected, the spectral residual method was used to detect salient regions probably containing targets. Then the improved 5-dimension SURF feature of the salient regions was extracted. Finally, the target was recognized using KRQQCF, and  the clutter and noise were suppressed effectively which improved the SNR. Experimental results indicate that the proposed algorithm is fast, effective and robust.     References | Related Articles | Metrics

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2D Bar Code Recovery in Highlight Area of Metal Parts WANG Jiajing1,2,ZHANG Shusheng1,HE Weiping1 2013, 47 (12):  1836-1841.  Abstract ( 1025 )   Save For optimization of the matching light source, this paper proposed a novel information recovery method based on the theory of stochastic resonance. This technique takes the advantage of noise to enlarge the dynamic range of image sensor when specifically added noise synchronizes with the image sensor system to activate the phenomenon of stochastic resonance. It investigated different types and strengths of noises to show the effect of variant distributions on the quality of retrieved information. The simulation results show that different types of noises have a corresponding strength, which makes the separability of output information reach extreme values. The results of locally overexposed experiment are consistent with the theoretic analysis, which also indicate that the recovery method of 2D bar code based on stochastic resonance could suppress the high light and improve image contrast.   References | Related Articles | Metrics

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A Method for  Deformation and Force Measurement of Micro-Cantilever Based on Local Feature Point Detecting and Matching LIU Hongtao,LIANG Zhenning,HU Wen,MO Jinqiu,WANG Shigang 2013, 47 (12):  1842-1847.  Abstract ( 785 )   Save  A method based on local feature point detecting and matching for force measurement of micro-cantilever was proposed. Images of micro-cantilever before and after deformation were obtained by optical microscope. Based on the enlarged speckle texture of the cantilever surface, the LOG (Laplace of Gaussian) feature points with the local extreme response value were detected in the scale space. An affine-invariant closed region was extracted for each LOG feature point. Then the centroid of this closed region could be calculated and treated as a feature point with subpixel positioning. Affine-invariant feature descriptors could be constructed and used for the matching of the corresponding points in images before and after deformation. The deformation of the microcantilever could be described by deflection curve obtained by fitting the displacement of the matching points， and then the force value as well as position applied by the loader on the cantilever were calculated using the least square method. The performance of the proposed method was verified by experiments based on actual deformation of microcantilever.   References | Related Articles | Metrics

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Acoustic Images Multi-Target Tracking Method Based on Modified Particle Filter MA Shan,ZHANG Tiedong,PANG Yongjie,WAN Lei 2013, 47 (12):  1848-1855.  Abstract ( 154 )   Save Aimed at the problem of underwater multi-target tracking using forward looking sonar images, a modified particle filter (PF) multi-target tracking method was proposed. By introducing the joint probabilistic data association (JPDA) method, a JPDA-PF algorithm was established. Thus particle weight could reflect the relationship between measurement and trajectory, which ensured the reliability and continuity of every trajectory. In order to increase the accuracy of tracking, the confirmation matrix was obtained by a double tracking threshold, including both relative distance and angle threshold. The methods of trajectory initialization and trajectory termination were complemented, which improved the whole tracking algorithm. Contrast tests on multi-target tracking were conducted, and the better performance of JPDAPF was verified. This paper provides a more effective method for multi-target tracking based on forward looking sonar. References | Related Articles | Metrics

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Optimal Class-Dependent Discretization-Based Fine-Grain Hypernetworks for  Classification of Microarray Data WANG Jin,ZHANG Jun,HU Baifan 2013, 47 (12):  1856-1862.  Abstract ( 180 )   Save To overcome the disadvantages in the traditional hypernetwork, an optimal class-dependent discretization (OCDD)based fine-grain evolutionary hypernetwork model was proposed, in which a continuous data was discretized as a fine-grain data and was used to evolve a hypernetwork classifier. With OCDD, the proposed fine-grain evolutionary hypernetwork lose less information than the traditional hypernetwork which directly convert a continuous data to a binary data. Moreover, fine-grain discrete data processing within the proposed hypernetwork model improves the quality of the probability estimation of a hypernetwork to the training data sets, and further enhances the performance of the hypernetwork classifier. The experimental results on colon, lung, prostate and Leukemia DNA microarray data sets show that the proposed method has a higher recognition rate and better robustness than the traditional evolutionary hypernetworks.   References | Related Articles | Metrics

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Digital Watermarking Algorithm for 3D Point Cloud Model Based on Clifford Algebra WANG Rui,JIN Linbo,TAO Lei,GUO Shuilin,WAN Wanggen 2013, 47 (12):  1863-1869.  Abstract ( 147 )   Save In this paper,  the generalized geometric representation of the 3D Point Cloud data was proposed based on Clifford algebra, where the expressions of 3D Point Cloud data were unified without losing their geometric meaning, and the geometric operation was coordinate-free for different dimensional spaces. The Clifford Fourier Transform was introduced into the digital watermarking algorithm for the 3D Point Cloud model, where point cloud models were mapped to the corresponding domain coefficients in space G3. Then the watermark was embedded or extracted based on these coefficients. The experimental results show that the algorithm has very good performance in affine transformation, reordering, simplification and noise, and is robust against attacks.   References | Related Articles | Metrics

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Moving Mode of Modular Soft Robot FEI Yanqiong，LV Haiyang,SHEN Xinyao 2013, 47 (12):  1870-1873.  Abstract ( 152 )   Save A soft robot consisting of several deformable spherical cells was presented. According to the deflating and inflating of the spherical cells, the size of each spherical cell could be changed, enabling the soft robot to move forward. In this paper, by using the  finite elasticity theory, the inflation of a modular spherical cell was modeled. The result shows that as the original radius decreases, the maximum pressure increases. The moving mode was analyzed in one circular with the deflating and inflating actions of 3 modular spherical cells. Finally an experiment was conducted to verify the moving mode of the soft robot. Key words： References | Related Articles | Metrics

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Dynamic Modeling of Underwater Self-Reconfigurable Robot with Kane’s Method WANG Xuyang,GE Tong,YANG Ke,WU Chao 2013, 47 (12):  1874-1880.  Abstract ( 159 )   Save The variation of configuration and complexity of external environment pose a great challenge to the dynamic modeling for underwater selfreconfiguration robot. In this paper, a general dynamic modeling method was proposed for underwater self-reconfigurable robot based on configuration expression and Kane’s method. The method analysing topological structure in graph theory was introduced to acquire a uniform mathematic expression for the multiform configurations present in underwater self-reconfigurable robot. Utilizing Kane’s method, a final closed-form motion equation for underwater selfreconfiguration robot was developed incorporating external environment actions into the model. Modeling example for a classic configuration verifies the applicability and effectiveness of the proposed method.   References | Related Articles | Metrics

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In Vivo Miniature Robot for Medical Applications WANG Zhen1,XIE Le1,2,YU Wenwei3,JIANG Jun1,ZHOU Zhaozheng1 2013, 47 (12):  1881-1887.  Abstract ( 285 )   Save In light of the fact that in different environments in human body, the body miniature medical robots have a different drive mechanism, this paper summarizes the overseas and domestic research status of invivo miniature robot including imitation of biological floating, special mechanical mechanism drive, in vitro special field(magnetic field, ultrasonic field) drive, and capsule endoscopy robot class. Besides, it analyzes the problems in motion control, operation safety of the current in vivo robot drive mechanism. Moreover, it discusses the key technology in vivo robot—the size of the miniaturization, multi degree of freedom with agile miniature drive mechanism, accurate and stable agile control system, effective lasting energy supplies, biocompatibility and so on. Furthermore, it elaborates on the application prospect and development direction of in vivo robot in clinical disease diagnosis and body surgery.   References | Related Articles | Metrics

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Edge Segmentation Based on Automatic Scale Selection XIANG Ke,WANG Xuanyin,CAO Songxiao 2013, 47 (12):  1888-1895.  Abstract ( 137 )   Save This paper presented a novel method to select the edge scale automatically, which could be used to split complicated interleaving edges into more meaningful edge segments that could be classified easily according to their features. First, edge extreme paths in Gaussian scale space were searched to obtain the characteristic scale for each edge point, by calculating the maximum distance the edge point travels from one scale level to adjacent one and analyzing the four forms of extreme path evolution. Then, interleaving edges were split into pieces with different scales according to their scale histogram. These edge pieces connecting with each other were combined through extreme path in scale space. Experimental results show that the proposed method is effective in edge segmentation based on characteristic scales and saliency of edge. Key words： References | Related Articles | Metrics

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Asymptotic Relaxation Based Collaborative Optimization FANG Pengya,CHANG Xinlong,HU Kuan,ZHANG Youhong 2013, 47 (12):  1896-1901.  Abstract ( 104 )   Save Collaborative optimization (CO) is easily influenced by the initial points, whose stability and convergence are poor. To solve this problem, the coupling consistency degree was defined to measure the consistency of the variables in different disciplines. The asymptotic relaxation based collaborative optimization method (COAR) was proposed，whose calculation process was divided into two phases. In the first phase, the relaxation factor of the system was computed based on the set coupling consistency degree, and the approximate global optimal solutions was solved, which were adopted as the initial points in the second phase. In the second phase, the relaxation factor was fixed again at a minimum according to the precision demand of the coupling consistency, and the final solutions were obtained. The standard numeral example of the reducer shows that the proposed method can greatly reduce the sensitivity to the initial points and effectively improve the convergence and the stability of CO.   References | Related Articles | Metrics

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Optimal Design of a Multirate Sampled-Data Control System Based on Robust Stability LI Xiayu1,JIN Huiliang1,ZHONG Qingchang2 2013, 47 (12):  1902-1906.  Abstract ( 143 )   Save This paper concerned the optimal design of a multirate sampled-data control system based on robust stability. For a system with a given F, a new condition for robust stability test of uncertain system was developed by extending Lyapunov upper bound method. For a system with an unknown uncertainty bound, the robust stability radius (RSR) was defined. The RSR calculation problem could be converted to a mathematical process of solving an equation by analyzing the robust stability test condition proposed. The equation was solved using numerical mathematical methods to get the analytical solution as RSR. As a function of F, the F optimization design could be achieved by a general optimization method to get the biggest RSR. With this F, the system could remain stable with the uncertain parameters varying set being the largest. Finally, a simple example was provided to test the feasibility of the proposed method.   References | Related Articles | Metrics

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Super-Directional Element Distribution Model of NLA Based on TR YANG Fuzhou,WANG Haiyan,SHEN Xiaohong,JING haixia 2013, 47 (12):  1907-1910.  Abstract ( 160 )   Save The establishment of a designed model was discussed based on time reversal(TR) of non-uniformed linear array(NLA) as a precondition of the target signal. By using the multi-path channel classic ray theory under symmetrical shallow water environment, and adopting the line of sight signal components as a reference factor, the impact factor of NLA’s TR focusing performance and directional diagram was derived. The conclusion shows that the designed model not only overcomes multi-path channel influence, but improves direction of arrival(DOA) accuracy under low signal-to-noise, based on TR adaptive correction characteristics of multi-path propagation delay, while the directional diagram F(θ) is related to bandwidth, arrayed factor di, multi-path M and snapshots K. The simulation results show that directional diagram of 7 elements distribution NLA has super-directivity compared to uniformed linear array via TR, and accurately estimates the target orientation under both -6 dB and -13 dB signal-to-noise condition.   References | Related Articles | Metrics

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Opportunistic Maintenance Model for Series Production Systems Based on Stochastic Degradations 陶红玉，周炳海 2013, 47 (12):  1911-1916.  Abstract ( 131 )   Save To reduce the failure rate and maintenance cost of production systems, an opportunistic maintenance model was proposed for a series production system which experiences stochastic degradation. A stationary gamma process was used to model the uncertain degradation for each unit of the system. By introducing integrated recovery factor of imperfective maintenance, a condition-based opportunistic maintenance policy was proposed. A formulation was developed for computing the expected value of the maintenance cost over a defined time horizon. The optimal inspection interval of the system could be found by minimizing the expected maintenance cost. Finally, a simulation experiment was conducted to show that the proposed model was feasible and valid.   References | Related Articles | Metrics

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Overlapping Coalition Generation Using Improved Continuous Particle Swarm Optimization DU Jiyong1,2,ZHANG Fengming1,HUI Xiaobin1,LI Yongbin1 2013, 47 (12):  1918-1923.  Abstract ( 131 )   Save An improved continuous particle swarm optimization (PSO) algorithm was proposed to solve the overlapping coalition generation problem. During the process of solution, an integer based encoding strategy was proposed which could represent the resource distribution of each agent to every task coalition, and the validation and revision algorithms for particle encoding were also presented. In order to improve the diversity of the swarm, a twostage initialization method of particle position was proposed. In the evolution process, the swarm trapping at the stagnation was reinitialized around its weighted centroid position, which could guide the swarm to avoid local extremum and accelerate the convergence of the algorithm. Contrastive experiments indicate that the proposed algorithm is effective. References | Related Articles | Metrics

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Solution to Multi-Line Layout Problems of Equipment Based on Improved Adaptive Genetic Algorithm ZHOU Na，MI Weijian，XU Ziqi,SHU Fan 2013, 47 (12):  1924-1929.  Abstract ( 128 )   Save To solve the multi-line layout problems of equipment with unequal area and fixed shape, a free-for-line layout strategy was proposed and the definition of net line space was presented. An optimization mathematic model was built with the objectives of the reversed logistics and net line space. Based on introducing the immune system population diversity as sign of population evolution, an improved adaptive genetic algorithm (IAGA) was put forward. The nonlinear adaptive adjustment function was achieved for crossover and mutation probability. Finally, the proposed algorithm was compared and evaluated. The results indicate that the algorithm can quickly obtain the nearly optimal solution. It is very useful for solving the combinatorial optimization problems of the multiline layout problem of equipment.   References | Related Articles | Metrics

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Image Deblocking with Adaptive Non-local Means Filter LIU Shu,WANG Ci 2013, 47 (12):  1930-1933.  Abstract ( 119 )   Save Common image compression standards such as JPEG and MPEG can lead to blocking artifacts which causes serious image degradation. In this paper, a non-local means filter for deblocking was proposed and its parameters were adaptively optimized by machine learning. The experimental results prove that the proposed algorithm constantly outperforms the peer ones on all kinds of images.   References | Related Articles | Metrics

Communication and Transportation

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Robustness of Carrier-Based Aircraft Sortie Network ZHENG Mao,WANG Chao,HUANG Sheng 2013, 47 (12):  1934-1939.  Abstract ( 112 )   Save To study the robustness of carrier-based aircraft sortie network, the sortie network model of carrier-based aircraft was established. Two kinds of simulation systems including random malfunction and enemy attack were proposed. In view of the complexity of aircraft sortie network, the flight deck plat theory was proposed to analyze the robustness of the flight deck. Finally, the influence of the upper structure and elevator number on the robustness of network was analyzed. The result indicates that random malfunction of sortie network is robustness, while, when attacked by enemy, the sortie network is not so robustness. Sortie network is highly dependent on the upper structure, elevators and forward area of angled deck. Finally, the influence of doubleisland upper structure and elevator number on the network robustness was analyzed. References | Related Articles | Metrics

Automation Technique, Computer Technology

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Adaptive Sliding Mode Synchronous Control of Locked Double-Container of Overhead Crane XU Pan，XU Weimin，TAN Yingying，LI Zhongfeng 2013, 47 (12):  1940-1947.  Abstract ( 143 )   Save To solve the problems of internal parameter perturbation, external disturbances and coupling interaction in synchronous control for double-container in overhead crane system, this paper proposed an adaptive sliding mode synchronous control method. First, based on the study of the operational characteristics of the double-container in locked work mode a coupling dynamic model of potential energy load for the double-container was established. Secondly, the time-varying sliding mode control method enhanced the robustness of sliding mode control in the reaching phase. Then, adaptive disturbance compensator restrained the uncertain disturbance which existed in synchronous control of the double-container, and reduces the gain value of switching function at the same time. Furthermore, instead of sign function, the Sigmoid function was introduced into the design of the switching function, in order to eliminate the chattering phenomenon. Lyapunov stability theory verified the global stability of the method. Numerical simulation result and the physical experimental result show the effectiveness of the approach. References | Related Articles | Metrics

Electrotechnology

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Fault Detection by Remote-Field Eddy Current Technique in Ferromagnetic Conductive Plate CHEN Peihua，HUANG Pingjie，ZHANG Wubo，TANG Huayi,ZHOU Zekui 2013, 47 (12):  1948-1956.  Abstract ( 150 )   Save The fundamental structure and the basic detection principle of the plate remote-field eddy current testing system were introduced. According to the distribution characteristics of the magnetic flux and the energy of the testing system, a novel concept related to the hollow area in the energy was proposed. Simulation techniques were used to obtain the distribution characteristics of the magnetic flux density in the direction which mainly influenced the output signal, in the plane where the detection coil was placed, and in the presence or otherwise of a fault in the conductor plate. In particular, the influence of flatbottom hole flaws of varying depths and radii on the magnetic flux density was analyzed. The analysis showed that the change in the magnetic flux density distribution was directly related to the shape of the fault. The test results for low-frequency remote-field signals for the plate were given with hole flaws appearing on the top or bottom of the plate. The test curves showed the different influences of the depth, radius, and location of the flaw on the detection signal for the tested material.   References | Related Articles | Metrics

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Analysis of Combustion and Systematic Performance of  MCFC/MGT Hybrid System LIU Aiguo1,WENG Yiwu2,ZENG Wen1,WANG Bing1 2013, 47 (12):  1957-1962.  Abstract ( 139 )   Save The reaction performance and influencing factors of catalytic combustor in the molten carbonate fuel cell/micro-gas turbine (MCFC/MGT) hybrid system were studied, and a hybrid system was designed based on the commercial gas turbine. The combination of numerical simulation and experimental study was used to study the catalytic combustor. The plug flow reactor model and detailed reaction mechanism of CH4 on Pt were used for the numerical simulation, and reaction performances of 3 different catalysts were studied in the experimental study. The design point parameters of the hybrid system were identified based on the commercial gas turbine, using the fuel cell temperature as the limiting condition. The results show that the model created can reflect the characteristics of the  catalytic combustion burner, the reaction activity of the perovskite and metal oxide catalyst is poorer than the noble metal catalyst. Though the efficiency of the system based on the commercial gas turbine is lower, this design is more practical.   References | Related Articles | Metrics

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Application of Adaptive Algorithm in Ship Power Protection HUANG Bin1,TAI Nengling1,WANG Peng2,NI Mingjie2,WEI Wei2,ZHANG Shurong2 2013, 47 (12):  1963-1967.  Abstract ( 129 )   Save This paper proposed an adaptive protection scheme for ship grids. The scheme was designed by offline and online computing. Offline calculations produced the protection setting values in all operation conditions， and the settings were  stored in a central control system. Online calculations assembled the operation data in a real-time way and identified the network topology. From the available settings, the corresponding values were chosen from the matching of operation conditions. A typical modelling for over-current adaptive protection were established, whose results proved the correctness and effectiveness of the scheme.   References | Related Articles | Metrics

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Calculation of Out-of-Plane Bending Moment at the Blade Root of  Offshore Wind Turbines by Statistic Extrapolation   XIA Yiqing,WANG Yingguang 2013, 47 (12):  1968-1973.  Abstract ( 190 )   Save According to IEC61400-3, NREL 5MW Monopile wind turbine and OC3Hywind wind turbine were studied to predict longterm loads of offshore wind turbines. This paper compiles FAST to include the functionality of calculating the wind loads on the tower in the simulation. Two statistics extrapolation methods, i.e. global maximum and block maximum, were used respectively to fit Gumbel distribution to predict the extreme load of out-of-plane bending moment at the blade root, and the results were compared. Further, after discussing different block sizes, the optimal block size was suggested. The comparison of research results with peak-over-threshold method shows that the block maximum method can effectively predict loads, thus providing references for offshore wind turbines load calculation.   References | Related Articles | Metrics

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A Fuzzy Game Optimization Model for Energy Market and Ancillary Market Joint Bidding GU Jie1,AI Xueyong2,YANG Guang1，XIE Da1,JIN Zhijian1 2013, 47 (12):  1974-1979.  Abstract ( 52 )   Save In the multi-market environment, the  total income of power suppliers is affected by the market mechanism, service cost, service price and market capacity distribution of major energy market and auxiliary service market in which they participate. At the same time, the  bidding strategies of archrivals have a significant influence on the profit, resulting in the fact that the optimal decision-making process of the multi-market capacity distribution of power suppliers is full of great uncertainty. Fuzzy game theory and fuzzy optimization theory were combined to establish a  joint bidding decision model for power suppliers in major and auxiliary service markets. Multi-objective optimization was completed, and simultaneously the problem of uncertainty and the competition game relationship between power suppliers were fully considered. Using the established model, under certain background, the determination of the corresponding bidding strategies in major/auxiliary market according to the optimal fuzzy game balance for the power suppliers was further discussed.   References | Related Articles | Metrics

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Transformer Winding Modal Parameter Identification Based on Complex Morlet Wavelet Transform GENG Chao1,WANG Fenghua1,HUANG Hua2,JIN Zhijian1 2013, 47 (12):  1980-1986.  Abstract ( 135 )   Save The modal parameter of transformer winding, as direct reflections of mechanical performance, is an important theoretical foundation in the field of transformer manufacturing and detection of winding condition based on vibration. To identify the modal parameters accurately, a modal experiment on a 10 kV transformer winding was conducted in this paper. A wavelet transforms method based on complex Morlet wavelet to identify winding natural frequency and damping ratio was proposed using the experiment to identify transformer winding modal parameters. Meanwhile, modal shapes were extracted using the least square method. The first four order modal parameters, including natural frequency, damping ratio and modal shapes were extracted from the vibration signal. The results demonstrate that all the natural frequencies are far away from the exciting frequency, and the modal shapes are symmetrical, which indicates that the design is appropriate. The parameters extracted by the general frequencydomain method PolyMax and the proposed method match well, which verifies the effectiveness of the proposed method in identifying modal parameters of transformer winding. References | Related Articles | Metrics