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第十届全国无损检测学术年会

作者： Ai Jun Yin Gui Yun Tian Liang Chen Jishan Zhang Brian Shaw State Key Laboratory of Mechanical Transmission College of Mechanical Engineering Chongqing Universi School of Automation Engineering University of Electronic Science and Technology of ChinaChengdu61 School of Electrical and Electronic Engineering Newcastle UniversityNewcastle upon TyneNE1 7RUUni Design unit School of Mechanical Engineering and SystemNewcastle UniversityNewcastle upon TyneNE1

Pulsed eddy current (PEC) technique generates responses over a wide range of frequencies, containing more spectral coverage than traditional eddy current *** current pulsed thermography (ECPT), a newly developed non-destructive testing (NDT) technique, has advantages such as rapid inspection of a large area within a short time, high spatial resolution, high sensitivity and stand-off measurement *** paper investigates ECPT for the evaluation of gear fatigue *** paper proposes a statistical method based on single channet blind source separation to extract details ot gear *** discussion of transient thermal distribution and patterns of fatigue contact surfaces as well as the non-contact surfaces have been *** addition, the measurement for gears with different cycles of fatigue tests by ECPTand the comparison results between ECPT with magnetic Barkhausen noise (MBN) have been *** comparison shows the competitive capability of ECPT in fatigue *** open access database of ECPT for gear fatigue evaluation is provided, and freely obtained to further analysis for gear fatigue evaluation.

关键词： Eddy current pulsed thermography Gear fatigue Evaluation Non-destructive testing

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Efficient kriging-based aerodynamic design of transonic airfoils: Some key issues 50

Efficient kriging-based aerodynamic design of transonic airf...

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50th AIAA Aerospace sciences Meeting Including the New Horizons Forum and Aerospace Exposition

作者： Liu, Jun Han, Zhong-Hua Song, Wen-Ping National Key Laboratory of Science and Technology on Aerodynamic Design and Research School of Aeronautics Northwestern Polytechnical University Youyi West Road No. 127 Xi'an 710072 China

ISBN: (数字)9781600869365

Today's complex time-consuming Computational Fluid Dynamics (CFD) codes stimulated the use of surrogate models in aerodynamic design. In this paper, an efficient Kriging-based airfoil design system is developed, including functionalities of optimization design and inverse design. In this system, design of Experiment techniques are used to select initial sample points in the design space and initial Kriging models are subsequently built for the cost function as well as the constraints, based on the sampled data;the Kriging models are refined repetitively by minimizing the Kriging approximated cost function or maximizing its Expected Improvement (EI) with genetic algorithm, until the global optimum is found. Four key issues about the design system is investigated: First, the performance of global optimization is tested for an analytical problem with extremely poor initial sampling;Second, the number of function evaluation needs to explore the global optimum for an analytical function is investigated with the number of design variables ranging from 2 to 40;Third, the optimization system is compared with the conventional quadratic response surface method (RSM) in drag minimization of transonic airfoil, which confirms that the Kriging-based optimization outperforms RSM method both in efficiency and percentage of drag reduction;Fourth, the design system is demonstrated for inverse design of a transonic airfoil, which also shows that it is very efficient and robust. Copyright © 2012 by the American Institute of Aeronautics and Astronautics, Inc.

关键词： Kriging

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Study on stress corrosion crack of austenitic stainless steel in simulated ocean environment

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Procedia Engineering 2012年 27卷 1538-1543页

作者： Meng Yan Qian Peng Qiwei Yin Science and Technology on reactor fuel and materials laboratory Nuclear Power Institute of ChinaP.O.Box436-4 610041ChengduChina Science and Technology on reactor system design technology laboratory Nuclear Power Institute of China P.O.Box622-502 610041ChengduChina

Recent studies on stress corrosion cracking properties of 321 bend pipe and pipe with weld, 316NG austenitic stainless steel pipe in ocean environment in virtue of slow strain rate tensile stress corrosion crack test are performed in different concentration of NaCl solution. Elongation and max tensile stress are selected as parameters to evaluate the SCC susceptibility based on the phenomenon that elongation and max stress fall as samples being exposed to NaCl solution environment, the results show that 316NG has the best stress corrosion crack resistance and 321 bend pipe materials behavior oppositely. In addition, the influence of differing strain rate and concentration of NaCl solution on properties of materials are researched, elongation increases along with tensile strain rate enhancement, mechanical properties are immune to variety of Cl- concentration from 3.5% to 26.5%.

关键词： stress corrosion crack austenitic stainless steel slow strain rate stress corrosion crack susceptibility

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Adaptive active piezoelectric energy harvester

International Journal of Digital Content Technology and its ...

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International Journal of Digital Content technology and its Applications 2012年第17期6卷 410-419页

作者： Zhang, Liwei Zheng, Guoqiang Li, Jishun School of Electronic Information Engineering Henan University of Science and Technology Luoyang China Henan Key Laboratory for Machinery Design and Transmission System Henan University of Science and Technology Luoyang China

For traditional piezoelectric energy harvesters, the harvested power is very low in the non-resonant frequency. In order to solve the problem, a new active piezoelectric energy harvester is designed. The electromechanical coupling model and the equivalent electrical model of the piezoelectric dynamic system are built. The adaptive active piezoelectric energy harvesting technology is investigated, and an analytical expression of an optimal control voltage harvested the maximum power is derived. Finally, an adaptive active piezoelectric energy harvesting circuit which can achieve this optimal control voltage is proposed. Experimental results reveal that the adaptive active piezoelectric energy harvester can significantly improve harvested power in the broadband. Therefore, it can be used in the energy supply field for the MEMS, WSN and embedded systems.

关键词： Energy harvesting

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Detecting infeasible traces in process models

Detecting infeasible traces in process models

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14th International Conference on Enterprise Information systems, ICEIS 2012

作者： Wang, Zhaoxia Wen, Lijie Zhu, Xiaochen Liu, Yingbo Wang, Jianmin School of Software Tsinghua University Beijing 100084 China Department of Computer Science and Technology Tsinghua University Beijing 100084 China Key Lab. for Information System Security Ministry of Education Beijing 100084 China National Laboratory for Information Science and Technology Beijing 100084 China Logistical Engineering University Chongqing 400016 China

ISBN: (纸本)9789898565105

Workflow testing is an important method of workflow analysis in design time. A challenging problem with trace-oriented test data generation in particular and trace-based workflow analysis in general is the existence of infeasible traces for which there is no input data for them to be executed. In this paper we build on the theory of workflow nets and introduce workflow nets where transitions have conditions associated with them. We then demonstrate that we can determine which execution traces, that are possible according to the control-flow dependencies, are actually possible taking the data perspective into account. This way we are able to more accurately determine in design time the infeasible traces caused by the correlation between transition conditions along this trace. Finally, we provide a solution to automatically detecting the shortest infeasible trace.

关键词： Infeasible traces Process models Workflow analysis

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Virtual assembly and kinematic simulation of gear form grinding machine based on Pro/E

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key Engineering Materials 2012年 522卷 819-822页

作者： Ren, Xiaozhong Xie, Fengkun School of Mechatronics Engineering Henan University of Science and Technology Luoyang 471003 China Henan Key Laboratory of Modern Mechanical Design and Transmission System Luoyang 471003 China

On the basis of establishing 3D modeling of gear form grinding machine, all levels of subassemblies of the grinding machine were assembled. Then the virtual assembly of total grinding machine was completed. Based on the kinematic simulation module of Pro/E-Mechanism, and combined with the virtual machine assembly model, the simulation analysis on machine movement was carried out. By simulating the actual working situation of the model, it could be checked whether the location, movement and load of the product could meet actual requirements before manufacturing the physical prototype of the product. This method is helpful for improving one-time success rate of new product development and saving product development cost. © (2012) Trans Tech Publications, Switzerland.

关键词： Grinding (machining)

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Enabling Dynamic Analysis of Anonymized Social Network Data

Enabling Dynamic Analysis of Anonymized Social Network Data

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International Conference on Cyber-Enabled Distributed Computing and Knowledge Discovery, CyberC

作者： Xuan Ding Wei Wang Key Laboratory of Information System Security Ministry of Education Tsinghua National Laboratory for Information Science and Technology School of Software Tsinghua University Beijing China

Anonymization is a widely used technique for the private publication of social network data. However, since the existing social network anonymization methods consider only one-time releases, they only reserve the static utility of the anonymized data. As social network evolves, these methods have posed severe challenges to the emerging requirement of dynamic social network analysis, which requires the dynamic utility of an evolving social network to be reserved for analysis. Instead of proposing a new anonymization method to handle dynamics, in this paper, we address these challenges by rebuilding connections between the sequentially published, anonymized data. By doing so, we have enabled a broad range of dynamic analysis to be applied to those already anonymized data without re-generating them. This suggests that our method is transparent to both the existing anonymization methods and the anonymized data. We adopt a combination of data-mining and graph-matching techniques to accomplish this task. The effectiveness of our method has been demonstrated on a series of real, dynamic social network data.

关键词： Social network services Instruction sets Communities Convergence Knowledge engineering Approximation algorithms Algorithm design and analysis

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SelectCast: Scalable Data Aggregation Scheme in Wireless Sensor Networks

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IEEE Transactions on Parallel and Distributed systems 2012年第10期23卷 1958-1969页

作者： Cheng Wang Changjun Jiang Shaojie Tang Xiang-Yang Li Key Laboratory of Embedded System and Service Computing Ministry of Education Shanghai China Department of Computer Science and Engineering University of Tongji China Department of Computer Science Illinois Institute of Technology Chicago IL USA Department of Computer Science and Engineering Tsinghua National Laboratory for Information Science and Technology (TNLIST) University of Tongji China

In this work, for a wireless sensor network (WSN) of n randomly placed sensors with node density \lambda \in [1,n], we study the tradeoffs between the aggregation throughput and gathering efficiency. The gathering efficiency refers to the ratio of the number of the sensors whose data have been gathered to the total number of sensors. Specifically, we design two efficient aggregation schemes, called single-hop-length (SHL) scheme and multiple-hop-length (MHL) scheme. By novelly integrating these two schemes, we theoretically prove that our protocol achieves the optimal tradeoffs, and derive the optimal aggregation throughput depending on a given threshold value (lower bound) on gathering efficiency. Particularly, we show that under the MHL scheme, for a practically important set of symmetric functions called divisible perfectly compressible (DPC) functions, including the mean, max, and various kinds of indicator functions, etc., the data from \Theta (n) sensors can be aggregated to the sink at the throughput of a constant order \Theta (1), implying that, our MHL scheme is indeed scalable.

关键词： Throughput Wireless sensor networks Temperature measurement Protocols Lattices Temperature sensors

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The analysis and comparison of the electromagnetic radiation characteristic of the Koch fractal dipole antennas

The analysis and comparison of the electromagnetic radiation...

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International Symposium on Antennas, Propagation and EM Theory (ISAPE)

作者： Ying Li Yang Mi Yinkun Wang Gaosheng Li The State Key Laboratory of Complex Electromagnetic Environmental Effects on Electronics & Information System China College of Electronic Science and Engineering National University of Defense Technology Changsha Hunan China College of Science National University of Defense Technology Changsha Hunan China

The electromagnetic radiation characteristic of the Koch fractal dipole antenna is analyzed, the logical assumption that the current along the Koch fractal dipole antenna obeys sine distribution is demonstrated, and the approximate expression of the magnetic vector potential of the Koch fractal dipole antenna is obtained. Using the magnetic vector potential, the far electromagnetic field is simulated, and the simulated results are compared with those obtained from the traditional symmetrical dipole antenna. For electrically large or electrically equivalent antennas, the results indicate that the electrical length of the Koch fractal dipole antenna has little influence on the radiation patterns. By using of this conclusion, the size of antennas can be reduced, as well as the least gain of antenna is satisfied. Therefore, it will be good for analytical design of multi-band and multi-functional antennas using fractal geometries. Finally, the rationalities of formulas and computations are validated by CST simulation.

关键词： Dipole antennas Fractals Antenna radiation patterns Vectors Directive antennas Fractal antennas Electromagnetic radiation

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A cloud-based watermarking method for health data security

A cloud-based watermarking method for health data security

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International Conference on High Performance Computing & Simulation (HPCS)

作者： Zhiwei Yu Clark Thomborson Chaokun Wang Jianmin Wang Rui Li Department of Computer Science and Technology Tsinghua University Beijing China Department of Computer Science University of Auckland New Zealand School of Software Key Laboratory for Information System Security Ministry of Education Tsinghua National Laboratory for Information Science and Technology(TNList) Tsinghua University Beijing China

Private health information once confined to local medical institutions is migrating onto the Internet as an Electronic Health Record (EHR) that is accessed by cloud computing. No matter where it is hosted, health data is subject to security breaches, privacy abuses, and access control violations. However, novel technologies have new vulnerabilities, and allow new mitigations. In this paper, we propose a watermarking method in the architecture of cloud computing, to mitigate the risks of insider disclosures. Our design and preliminary implementation are accomplished by exploiting the MapReduce mechanism in the cloudlet we built. Our evaluation shows that our proposal addresses all of the requirements of the Cloud Oriented Architecture (COA) framework of the Jericho Forum.

关键词： Watermarking Medical services Cloud computing Computer architecture Cryptography Organizations

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