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2011 IEEE International Symposium on Antennas and Propagation(APSURSI 2011)

作者： Y. Tawk S. Hemmady C. G. Christodoulou J. Costantine G. Balakrishnan Electrical and Computer Eng. Dept. University of New Mexico Albuquerque NM USA Electrical Engineering Dept. California State University Fullerton Fullerton CA USA Center for High Technology Materials University of New Mexico Albuquerque NM USA

ISBN: (纸本)9781424495627;9781424495634

This paper presents a new antenna scheme for cognitive radio communication. The antenna structure consists of two ports. The first antenna port is a UWB structure for channel sensing while the second one is a reconfigurable structure for communication. The reconfigurability is based on integrating laser diodes within the antenna substrate in order to activate the photoconductive switches. A prototype was fabricated and tested. A good agreement between the simulation and the measurement data is noticed. A coupling of less than -20 dB is achieved between the 2 antenna ports.

关键词： cognitive radio coupling photoconductive switches reconfigurable antenna ANTENNA antennae measurement data Cognitive radio harbors configurability antenna design Radiocommunication

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Radiation Defect-Induced Lattice Contraction of InP

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MRS Online Proceedings Library 2011年第1期74卷 517-522页

作者： C. R. Wie T. Jones T. A. Tombrello T. Vreeland F. Xiong Z. Zhu G. Burns F. H. Dacol Dept. of Electrical and Computer Engineering State University of New York at Buffalo Amherst USA Mathematics and Astronomy and Engineering and Applied Sciences California Institute of Technology Div. of Physics Pasadena USA IBM Thomas Watson Research Center Yorktown Heights USA

We studied the lattice strain induced in the MeV ion bombarded InP crystals and the annealing behaviors of lattice strain, Raman line shift, and linewidth. The lattice spacing for the planes parallel to the surface decreases as a result of irradiation, and amounts to a strain of −0.061% for (100) face, −0.056% for (110) face, and −0.050% for (111) face for 15 MeV Cl bombarded samples to a dose of 1.25E15 ions/cm2. The negative lattice strain, Raman line shift, and line width completely recover at 450°C, and show a major recovery stage at 250°C – 350°C.

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Hybrid Spectral Domain Ray Tracing Algorithm for Fast Analysis of On-Chip Terahertz Integrated Antenna

Hybrid Spectral Domain Ray Tracing Algorithm for Fast Analys...

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2011 IEEE International Symposium on Antennas and Propagation(APSURSI 2011)

作者： Daniel M. Hailu Mohammad Neshat Safieddin Safavi-Naeini CIARS (Center for Intelligent Antenna and Radio Systems) Electrical and Computer Engineering Dept. University of Waterloo 200 University Avenue West Waterloo ON. N2L 3G1 Canada Department of Electrical and Computer Engineering University of Waterloo Waterloo ON. N2L 3G1 Canada

ISBN: (纸本)9781424495627;9781424495634

We present a computationally efficient general Hybrid Spectral Ray Tracing (HSRT) method that requires one spectral domain integration step for each observation point. The HSRT method is capable of modeling arbitrary three-dimensional dielectric and metallic structures. As an example, the HSRT method is applied to on-chip dipole antenna backed by Silicon lens and integrated with a 180-GHz VCO in SiGe:C BiCMOS technology. We compare and validate the HSRT method for different reflection orders with measurements.

关键词： Antennas method of moments multi-level fast multi-pole method geometrical optics graphics processing unit (GPU) hyper-hemispherical lens lens antennas spectral ray tracing terahertz radiation ANTENNA Spectral domain Ray tracing system-on-chip terahertz metal structure BiCMOS technology Integrate DIPOLE ANTENNAS antennae HYBRID Hybrid electric vehicles

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Visualizing the Blogosphere with BlogConnect

Visualizing the Blogosphere with BlogConnect

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IEEE International Conference on and IEEE International Confernece on Social Computing (SocialCom) Privacy, Security, Risk and Trust (PASSAT)

作者： Justus Broß Patrick Schilf Maximilian Jenders Christoph Meinel Zhejiang University College of Electrical Engineering Potsdam China Dept. of Human and Artificial Intelligence Systems University of Fukui Fukui-shi Japan Department of Systems and Computer Science Howard University Washington D.C. Department of Mathematics and Computer Science Univ. of MD Eastern Shore Princess Anne MD Dept. of Information and Media techlnology University of Fukui Fukui-shi Japan Dept. of Information Technology Clayton State University Morrow GA

It can be highly meaningful for individuals, institutions and even governments to extract reliable and insightful trends, opinions or particular pieces of information out of the network single web logs are embedded in - the blogo sphere. However, there has been virtually little in the way of user interfaces designed for the exploration and information gathering from the blogo sphere as a whole to allow for an integrated knowledge collection and information extraction tool. Users have to rely on their own capability to find, select or filter entries and navigate through this complex network, a task that can easily become tedious. An approach to solve this problem could be BLOGCONNECT presented in the following, a tool to visualize the inherent network characteristics of and the aggregated knowledge pool of the blogosphere.

关键词： Blogs Data visualization Visualization Databases Communities Web services USA Councils

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Multibeam SATCOM systems design with physical layer security

Multibeam SATCOM systems design with physical layer security

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IEEE International Conference on Ubiquitous Wireless Broadband (ICUWB)

作者： Jiang Lei Zhu Han M. A. Vázquez-Castro Are Hjørungnes Department Telecommunication and Systems Engineering Universitat Autónoma de Barcelona Spain Dept. Telecom. and Systems Engineering Universitat Autónoma de Barcelona Spain Electrical & Computer Engineering Department University of Houston USA Universitat Autonoma de Barcelona Barcelona Catalunya ES UNIK - University Graduate Center University of Oslo Norway

Recently, physical layer security (PHY-SEC) has been investigated for wireless communications to prevent eavesdropping without upper layer data encryption. This paper addresses multibeam satellite secure communication using PHY-SEC. We propose a novel system design that minimizes the satellite transmit power subject to the individual secrecy rate requested per user constraints. An iterative algorithm is proposed to update the transmission power of each beam and to achieve the optimal power allocation strategy. The convergence property of the algorithm is proved under justifiable assumptions. The performance is evaluated taking into account the impact of the channel condition with given individual secrecy rate requirement.

关键词： Interference Satellites Signal to noise ratio Satellite broadcasting Security Antennas Attenuation

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Growth temperature and growth rate dependency on reactor pressure for InN epilayers grown by HPCVD

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Physica Status Solidi (C) Current Topics in Solid State Physics 2011年第7-8期8卷 2059-2062页

作者： Buegler, Max Gamage, Sampath Atalay, R. Wang, J. Senevirathna, M.K.I. Kirste, R. Xu, T. Jamil, M. Ferguson, I. Tweedie, J. Collazo, R. Hoffmann, A. Sitar, Z. Dietz, N. Department of Physics and Astronomy Georgia State University 29 Peachtree Center Ave. Atlanta GA 30303 United States Institut für Festkörperphysik Technische Universität Berlin Berlin Germany School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta GA 30332 United States Dept. Electrical and Computer Engineering University of North Carolina Charlotte Charlotte NC 28223 United States Dept. Materials Science and Engineering North Carolina State University Raleigh NC 27695 United States

This contribution presents results on achievable growth temperatures and growth rates as a function of reactor pressure for the growth of InN by high-pressure chemical vapour deposition (HPCVD). The InN epilayers were grown at reactor pressures ranging from atmospheric pressure to 19 bar. The results show that the InN growth temperature increased linearly with the reactor pressure from 759 °C to 876 °C. The growth rate decreases from 127 nm/h to 20 nm/h as the reactor pressure is increased from 1 bar to 19 bar. The structural, optical, and electrical properties of the epitaxial layers were analyzed by X-ray diffraction, Raman spectroscopy, IR reflection spectroscopy, and optical transmission spectroscopy. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

关键词： Growth temperature

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Integrating systems health management with adaptive controls for a utility-scale wind turbine

Integrating systems health management with adaptive controls...

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AIAA Infotech at Aerospace Conference and Exhibit 2011

作者： Frost, Susan A. Goebel, Kai Trinh, Khanh V. Balas, Mark J. Frost, Alan M. Intelligent Systems Division NASA Ames Research Center POB 1 M/S 269-3 Moffett Field CA 94035 United States NASA Ames SGT POB 1 M/S 269-3 Moffett Field CA 94035 United States Electrical and Computer Engineering Dept. University of Wyoming Laramie WY 82070 United States not available PO Box 30 3595 Hwy 130 Centennial WY 82055 United States

ISBN: (纸本)9781600869440

Increasing turbine up-time and reducing maintenance costs are key technology drivers for wind turbine operators. Components within wind turbines are subject to considerable stresses due to unpredictable environmental conditions resulting from rapidly changing local dynamics. systems health management has the aim to assess the state-of-health of components within a wind turbine, to estimate remaining life, and to aid in autonomous decision-making to minimize damage. Advanced adaptive controls can provide the mechanism to enable optimized operations that also provide the enabling technology for systems Health Management goals. The work reported herein explores the integration of condition monitoring of wind turbine blades with contingency management and adaptive controls. Results are demonstrated using a high fidelity simulator of a utility-scale wind turbine.

关键词： Decision making

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XML-Based Reusable Component Repository for Embedded Software

XML-Based Reusable Component Repository for Embedded Softwar...

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IEEE Annual computer Software and Applications Conference Workshops (COMPSACW)

作者： Chih-Hung Chang Chih-Wei Lu William C. Chu Chao-Tung Yang Pao-Ann Hsiung Nien-Lin Hsueh Chorng-Shiuh Koong Kuei-Kai Shao Dept. of Information Management Hsiuping Institute of Technology Taichung Taiwan (R.O.C.) Dept. of Computer Science Tunghai University Taichung Taiwan (R.O.C.) Dept. of Information Engineering and Computer Science Feng Chia University Taichung Taiwan (R.O.C.) Dept. of Computer and Information Science Taichung University Taichung City Taiwan (R.O.C.) Service Systems Technology Center Industrial Technology Research Institute Hsinchu Taiwan (R.O.C.)

In the development stage of the embedded system, the market demand and system development trend will be influence by the Time to Market. Reliable and fast system deployment is not easy to implement. Reduced price and system development time can increase the product value. Thus the component re-use library can help reduce the development time, this kind of design can reduce the emergence of rewriting and raise the efficiency by a wide margin. We design and study the reusable component in this research, proposing a prototype database based on XML. This technique has many advantages like reduces the time required for storage, improves the overall efficiency of the system, shortens the development time, increases reliability and reduces the risks handling etc.

关键词： XML Unified modeling language Libraries Software Relational databases Electronic mail

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Wireless acoustic wave sensors and systems for harsh environment applications

Wireless acoustic wave sensors and systems for harsh environ...

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IEEE Topical Conference on Wireless Sensors and Sensor Networks (WiSNet)

作者： M. Pereira da Cunha R.J. Lad P. Davulis A. Canabal T. Moonlight S. Moulzolf D.J. Frankel T. Pollard D. McCann E. Dudzik A. Abedi D. Hummels G. Bernhardt Environetix Technologies Corp. Target Technology Center Orono ME Dept. of Electrical and Computer Engineering University of Maine Orono ME U.S.A. Laboratory for Surface Science & Technology University of Maine Orono ME U.S.A. Environetix Technologies Corp. Target Technology Center Orono ME USA

This paper reviews current progress in the area of wireless microwave acoustic sensor technology, and discusses advances in wireless interrogation systems that can operate in harsh environments. The use of wireless, battery-free, low maintenance surface acoustic wave (SAW) sensors has been successfully demonstrated in applications including high temperature turbine engines and inflatable aerospace structures. Wireless interrogation of multiple sensors up to 910°C has been established and sensor tests in gas turbine engine are reported. This paper elaborates on several aspects of the technology, including: high-temperature thin-film electrode and sensor development, temperature cycling, thermal-shock behavior, testing in turbine engine environments, sensor packaging and attachment, wireless operation, and adaptation to energy and industrial applications.

关键词： Temperature sensors Surface acoustic waves Wireless communication Wireless sensor networks Temperature measurement Films

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Ac Stability of High Power Factor Multi-Pulse Rectifiers

Ac Stability of High Power Factor Multi-Pulse Rectifiers

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2011 IEEE Energy Conversion Congress and Exposition (ECCE 2011)

作者： Rolando Burgos Dushan Boroyevich Fred Wang Kamiar Karimi Gerald Francis ABB Corporate Research 940 Main Campus Dr. Raleigh NC 27606 Center for Power Electronics Systems (CPES) The Bradley Dept. of Electrical and Computer Engineering Virginia Polytechnic Institute and State University Blacksburg VA 24061 The Boeing Company Seattle WA 98124

ISBN: (纸本)9781457705427;9781457705410

This paper studies the ac stability of high power factor multi-pulse rectifiers, proposing a new stability criterion to assess this condition under constant power load dynamics. Specifically, based on the multivariable generalized Nyquist stability criterion developed by MacFarlane and Postlethwaite, this paper shows how the fundamental stability problem at such ac interface is reduced to a single-input single-output (SI-SO) case. It is shown that the ac stability is fully determined by the SISO return-ratio of the d-d channel--or the power transfer channel of the desired d-q frame alignment;that is, the stability is solely determined by the d-d channel input and output impedances. Correspondingly, it is shown that the q-q channel trajectory on the complex plane is such that it cannot encircle the critical point (-1+j0) and be the cause of instability. Furthermore, it is shown that the multi-pulse rectifier stability can be indistinctively determined at either ac or dc terminals, which has great significance from a practical point of view. Simulation and experimental results are used to verify the implications of the proposed stability criterion.

关键词： Nyquist stability theorem generalized Nyquist stability criterion multi-pulse rectifier high power factor

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