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A Design Method of Bending Deflection on Hyper-Static Leaf Spring

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Wuhan University Journal of Natural Sciences 2015年第1期20卷 87-92页

作者： XIE Feng ZHOU Yong peng Sisi Wuhan Institute of Marine Electric Propulsion CSIC

A group of leaf springs which provides the flexible support of stator is designed to satisfy the requirement of low vibration motor at megawatt （MW） level. Spring steel 65Mn is chosen as the material of the leaf spring. The size of the leaf spring is obtained by calculation and load analysis according to a deflection formula. The deflection and stiffness of the single leaf spring is calculated with both theoretical method and finite element analysis （FEA）. A deflection test platform is established based on actual force and boundary condition to verify the deflection and stiffness of the leaf spring. The results show that the maximal deflection of the three pieces of 1.2 mm leaf spring group is 0.71 mm and the stiffness of the leaf spring group is 364 N/mm, which satisfies the requirements of the motor. The design method is also applicable for other MW power level motors.

关键词： leaf spring low vibration deflection finite element analysis (FEA)

A Python Security Analysis Framework in Integrity Verification and Vulnerability Detection

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Wuhan University Journal of Natural Sciences 2019年第2期24卷 141-148页

作者： peng Shuanghe LIU Peiyao HAN Jing Beijing Key Laboratory of Security and Privacy in Intelligent Transportation Beijing Jiaotong University

Python is widely used in web crawler, machine learning, data analysis and so on. However, there is no guarantee that Python scripts are trusted in their whole lifetime because of system insecurity. When the system is attacked, scripts in the computer are likely to be tampered with. Therefore, the trustworthiness of Python scripts needs to be checked through different configuration strategies, including integrity verification and vulnerability detection. In this paper, integrity verification and vulnerability detection are based on two Python scripts, an original Python script and a current Python script, and the original Python script is assumed to has no vulnerabilities. By comparing with the original script, we can find out whether the current script is integrity or not and detect whether there are vulnerabilities if the integrity of the current file is destroyed. Integrity verification with Hash functions is not applied in some cases. In this mode, any changes including blank lines added are considered illegal. So loose integrity verification by combining UNIX diff tool with abstract syntax trees is proposed. The vulnerability detection starts from the premise that the original Python script has no vulnerabilities, and taint analysis is applied on the vulnerability detection framework Bandit to find vulnerabilities. Besides, in order not to change the usage of Python, both integrity verification and vulnerability detection modules are embedded in Python interpreter. The experiments show that the performance of security analysis framework is good and Bandit with taint can greatly reduce the false positive results without affecting the performance.

关键词： Python integrity verification vulnerability detection

Flexible Active Distribution System Management Considering Interaction with Transmission Networks Using Information-gap Decision Theory

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CSEE Journal of Power and Energy Systems 2016年第4期2卷 76-86页

作者： Tianyang Zhao Jianhua Zhang peng Wang State Key Laboratory of Alternate Power System with Renewable Energy Resources North China Electric Power UniversityBeijing 102206China School of Electrical and Electronic Engineering Nanyang Technological UniversitySingapore S639798

In this paper,a flexible management method is proposed for an active distribution system(ADS)with distributed energy resources(DERs)integrated,where DERs can provide spinning reserves to transmission *** method,based on the information-gap decision-making theory(IGDT)theory,could be of use to the ADS operator(ADSO)from either the opportunistic or robust perspective when reserve is called by the independent system operator(ISO).Two IGDT uncertainty models are employed to depict the characteristics of reserve uncertainty in centralized and decentralized control *** reactive power of each DER is managed by the ADSO in the immunity functions,which are reformulated as bi-level biobjective optimization problems.A hybrid multi-objective differential evolutional algorithm(MODE)is proposed to solve the optimization *** relationship between the uncertainty levels and robust/opportunistic limits is revealed by the Pareto fronts obtained by *** of the proposed method is demonstrated based on simulation results of a 33-bus and 123-bus test system.

关键词： Active distribution system bi-level multiobjective optimization information-gap decision-making theory reserve uncertainty

Change of the mode of failure by interface friction and width-to-height ratio of coal specimens

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Journal of Rock Mechanics and Geotechnical Engineering 2015年第3期7卷 256-265页

作者： Gamal Rashed Syd S.peng Department of Mining Engineering West Virginia University

Bumps in coal mines have been recognized as a major hazard for many years. These sudden and violent failures around mine openings have compromised safety, ventilation and access to mine *** studies showed that the violence of coal specimen failure depends on both the interface friction and width-to-height（W/H） ratio of coal specimen. The mode of failure for a uniaxially loaded coal specimen or a coal pillar is a combination of both shear failure along the interface and compressive failure in the coal. The shear failure along the interface triggered the compressive failure in coal. The compressive failure of a coal specimen or a coal pillar can be controlled by changing its W/H ratio. As the W/H ratio increases, the ultimate strength increases. Hence, with a proper combination of interface friction and the W/H ratio of pillar or coal specimen, the mode of failure will change from sudden violent failure which is brittle failure to non-violent failure which is ductile failure. The main objective of this paper is to determine at what W/H ratio and interface friction the mode of failure changes from violent to non-violent. In this research, coal specimens of W/H ratio ranging from 1 to 10 were uniaxially tested under two interface frictions of 0.1 and 0.25, and the results are presented and discussed.

关键词： Bump Burst Coal strength Violent failure Width-to-height(W/H) ratio Interface friction Stressestrain curve

Enhancing Firefly Algorithm with Best Neighbor Guided Search Strategy

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Wuhan University Journal of Natural Sciences 2019年第6期24卷 524-536页

作者： WU Shuangke WU Zhijian peng Hu School of Computer Science Wuhan UniversityWuhan 430072HubeiChina School of Information Science and Technology Jiujiang UniversityJiujiang 332005JiangxiChina

Firefly algorithm(FA)is a recently-proposed swarm intelligence *** has shown good performance in solving various optimization *** to the standard firefly algorithm and most of its variants,a firefly migrates to every other brighter firefly in each ***,this method leads to defects of oscillations of positions,which hampers the convergence to the *** address these problems and enhance the performance of FA,we propose a new firefly algorithm,which is called the Best Neighbor Firefly Algorithm(BNFA).It employs the best neighbor guided strategy,where each firefly is attracted to the best firefly among some randomly chosen neighbors,thus reducing the firefly oscillations in every attraction-induced migration stage,while increasing the probability of the guidance a new better ***,it selects neighbors randomly to prevent the firefly form being trapped into a local *** experiments are conducted to find out the optimal parameter *** verify the performance of BNFA,13 classical benchmark functions are *** show that BNFA outperforms the standard FA and other recently proposed modified FAs.

关键词： firefly algorithm(FA) global optimization random neighbour exploration and exploitation

Propagation of the Bessel-Gaussian Beams Generated by Coherent Beam Combining in Oceanic Turbulence

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Journal of Communications and Information Networks 2019年第3期4卷 25-37页

作者： peng Yue Dongling Xu Xiang Yi State Key Laboratory of Integrated Service Networks Xidian UniversityXi’an 710071China

Coherent beam combining(CBC)is recently used to generate high power vortex beams which are strongly required in specific *** this paper,based on the extended Huygens-Fresnel principle,the exact theoretical forms for the intensity distribution of CBC Bessel-Gaussian beams(BGBs)in turbulent ocean are *** show the superiority of CBC BGBs in turbulent channels,the comparison in the intensity evolution of CBC BGBs with ideal BGBs is *** is found that the beam spreading of CBC BGBs is smaller than that of ideal BGBs under the same oceanic turbulence ***,the effect of the beam parameters and channel parameters on the quality of CBC BGBs is also *** results show that the oceanic turbulence with a higher rate of dissipation of kinetic energy per unit mass of fluid,lower dissipation rate of the mean-squared temperature,or smaller ratio of temperature and salinity contributions to the refractive index spectrum has smaller impact on CBC ***,the increasing number of the beamlets,the increasing waist width of each beamlet,and the decreasing radius of the beam distribution cause the optical energy to be more concentrated,and thus leading to a longer non-diffraction propagation distance.

关键词： CBC technology BGBs beam spreading oceanic turbulence

Current control for a shunt hybrid active power filter using recursive integral PI

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控制理论与应用（英文版） 2009年第1期7卷 77-80页

作者： Wei ZHAO An LUO Ke peng Xia DENG College of Electrical and Information Engineering Hunan University Changsha Hunan 410082 China

This paper presents a current control method for a shunt hybrid active power filter （HAPF） using recursive integral PI algorithm. The method improves the performance of the HAPF system by reducing the influence of detection accuracy, time delay of instruction current calculation and phase displacement of output filter. Fuzzy logic based set-point weighing algorithm is combined in the control scheme to enhance its robustness and anti-interference ability. The proposed algorithm is easy to implement for engineering applications and easy to compute. Experiment results have verified the validity of the proposed controller. Furthermore, the proposed recursive integral PI algorithm can also be applied in the control of periodic current as in AC drivers.

关键词： Power electronics Shunt hybrid active power filter Recursive integral PI Fuzzy inference

New Explorations on Cannon's Contributions and Generalized Solutions for Uniform Linear Motion Blur Identification

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Journal of Computer Science & Technology 2012年第1期27卷 174-186页

作者： Lu Wang Hong-Yan Zhang Si-Long peng The National Engineering and Technology Research Center for ASIC Design Institute of AutomationChinese Academy of SciencesBeijing 100190China The Key Laboratory of Complex Systems and Intelligence Science Institute of AutomationChinese Academy of Sciences Beijing 100190China Sino-European Institute of Aviation Engineering Civil Aviation University of ChinaTianjin 300300China

Existing frequency-domain-oriented methods of parameter identification for uniform linear motion blur （ULMB） images usually dealt with special scenarios. For example, blur-kernel directions were horizontal or vertical, or degraded images were of foursquare dimension. This excludes those identification methods from being applied to real images, especially to estimate undersized or oversized blur kernels. Pointing against the limitations of blur-kernel identifications, discrete Fourier transform （DFT）-based blur-kernel estimation methods are proposed in this paper. We analyze in depth the Fourier frequency response of generalized ULMB kernels, demonstrate in detail its related phase form and properties thereof, and put forward the concept of quasi-cepstrum. On this basis, methods of estimating ULMB-kernel parameters using amplitude spectrum and quasi-cepstrum are presented, respectively. The quasi-cepstrum-oriented approach increases the identifiable blur-kernel length, up to a maximum of half the diagonal length of the image. Meanwhile, directing toward the image of undersized ULMB, an improved method based on quasi-cepstrum is presented, which ameliorates the identification quality of undersized ULMB kernels. The quasi-cepstrum-oriented approach popularizes and applies the simulation-experiment- focused DFT theory to the estimation of real ULMB images. Compared against the amplitude-spectrum-oriented method, the quasi-cepstrum-oriented approach is more convenient and robust, with lower identification errors and of better noiseimmunity.

关键词： Fourier amplitude spectrum phase perpendicular relation uniform linear motion blur identification quasicepstrum

A Novel Improved Bird Swarm Algorithm for Solving Bound Constrained Optimization Problems

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Wuhan University Journal of Natural Sciences 2019年第4期24卷 349-359页

作者： WANG Yuhe WAN Zhongping peng Zhenhua School of Mathematics and Statistics Wuhan University

Bird swarm algorithm(BSA), a novel bio-inspired algorithm, has good performance in solving numerical optimization problems. In this paper, a new improved bird swarm algorithm is conducted to solve unconstrained optimization problems. To enhance the performance of BSA, handling boundary constraints are applied to fix the candidate solutions that are out of boundary or on the boundary in iterations, which can boost the diversity of the swarm to avoid the premature problem. On the other hand, we accelerate the foraging behavior by adjusting the cognitive and social components the sin cosine coefficients. Simulation results and comparison based on sixty benchmark functions demonstrate that the improved BSA has superior performance over the BSA in terms of almost all functions.

关键词： improved bird swarm algorithm handling boundary constraints foraging behavior heuristic algorithm