检索结果-内蒙古大学图书馆

Symposium on Sensors, Actuators and Microsystems General Session - 223rd Meeting of the Electrochemical Society

作者： Sekhar, P.K. Subramaniyam, K. Karacolak, T. Asili, M. Seran, S. Nanomaterials and Sensors Laboratory School of Engineering and Computer Science Washington State University Vancouver United States RF Research Laboratory School of Engineering and Computer Science Washington State University Vancouver United States Department of Electrical and Computer Engineering Mississippi State University United States

ISBN: (纸本)9781607684701

The article describes the investigation of electromagnetic properties of YSZ for wireless gas sensor applications. In particular, the dielectric properties of YSZ were found with a view to implement on-chip antennas. Agilent Dielectric Probe Kit and network analyzer were used for dielectric constant and dielectric loss measurements. The dielectric properties were measured as a function of YSZ sintering temperature. The average dielectric constant (over frequency) of YSZ was seen to increase with an increase in sintering temperature. The average loss tangent (over frequency) was seen to decrease with an increase in sintering temperature. Substrates based on the dielectric ceramic materials such as YSZ, Al2O3, and Low Temperature Co-fired Ceramic are promising candidates for antenna miniaturization because of their high permittivity, low loss, light weight, low cost, and market availability. © The Electrochemical Society.

关键词： Yttria stabilized zirconia

来源：评论

学校读者我要写书评

暂无评论

POLARBEAR constraints on cosmic birefringence and primordial magnetic fields

引用

Physical Review D 2015年第12期92卷 123509-123509页

作者： Peter A. R. Ade Kam Arnold Matt Atlas Carlo Baccigalupi Darcy Barron David Boettger Julian Borrill Scott Chapman Yuji Chinone Ari Cukierman Matt Dobbs Anne Ducout Rolando Dunner Tucker Elleflot Josquin Errard Giulio Fabbian Stephen Feeney Chang Feng Adam Gilbert Neil Goeckner-Wald John Groh Grantland Hall Nils W. Halverson Masaya Hasegawa Kaori Hattori Masashi Hazumi Charles Hill William L. Holzapfel Yasuto Hori Logan Howe Yuki Inoue Gregory C. Jaehnig Andrew H. Jaffe Oliver Jeong Nobuhiko Katayama Jonathan P. Kaufman Brian Keating Zigmund Kermish Reijo Keskitalo Theodore Kisner Akito Kusaka Maude Le Jeune Adrian T. Lee Erik M. Leitch David Leon Yun Li Eric Linder Lindsay Lowry Frederick Matsuda Tomotake Matsumura Nathan Miller Josh Montgomery Michael J. Myers Martin Navaroli Haruki Nishino Takahiro Okamura Hans Paar Julien Peloton Levon Pogosian Davide Poletti Giuseppe Puglisi Christopher Raum Gabriel Rebeiz Christian L. Reichardt Paul L. Richards Colin Ross Kaja M. Rotermund David E. Schenck Blake D. Sherwin Meir Shimon Ian Shirley Praween Siritanasak Graeme Smecher Nathan Stebor Bryan Steinbach Aritoki Suzuki Jun-ichi Suzuki Osamu Tajima Satoru Takakura Alexei Tikhomirov Takayuki Tomaru Nathan Whitehorn Brandon Wilson Amit Yadav Alex Zahn Oliver Zahn School of Physics and Astronomy Cardiff University Cardiff CF10 3XQ United Kingdom Department of Physics University of California San Diego California 92093-0424 USA International School for Advanced Studies (SISSA) Via Bonomea 265 34136 Trieste Italy Department of Physics University of California Berkeley California 94720 USA Department of Astronomy Pontifica Universidad Catolica Santiago Chile Computational Cosmology Center Lawrence Berkeley National Laboratory Berkeley California 94720 USA Space Sciences Laboratory University of California Berkeley California 94720 USA Department of Physics and Atmospheric Science Dalhousie University Halifax Nova Scotia B3H 4R2 Canada Physics Department McGill University Montreal Quebec H3A 0G4 Canada Department of Physics Blackett Laboratory Imperial College London London SW7 2AZ United Kingdom Department of Physics and Astronomy University of California Irvine California 92697-4575 USA Center for Astrophysics and Space Astronomy University of Colorado Boulder Colorado 80309 USA Department of Astrophysical and Planetary Sciences University of Colorado Boulder Colorado 80309 USA Department of Physics University of Colorado Boulder Colorado 80309 USA High Energy Accelerator Research Organization (KEK) Tsukuba Ibaraki 305-0801 Japan SOKENDAI (The Graduate University for Advanced Studies) Hayama Miura District Kanagawa 240-0115 Japan Kavli IPMU (WPI) UTIAS The University of Tokyo Kashiwa Chiba 277-8583 Japan Department of Physics Princeton University Princeton New Jersey 08544 USA Physics Division Lawrence Berkeley National Laboratory Berkeley California 94720 USA AstroParticule et Cosmologie Univ Paris Diderot Centre National de la Recherche Scientifique/l’Institut National de Physique Nucléaire et de Physique des Particules Commissariat à l’Energie Atomique/Institut de recherche sur les lois fondamentales de l’Univers Obs de Paris Sorbonne Paris Cité France Department of Astronomy and Astrophysics

We constrain anisotropic cosmic birefringence using four-point correlations of even-parity E-mode and odd-parity B-mode polarization in the cosmic microwave background measurements made by the POLARization of the Background Radiation (POLARBEAR) experiment in its first season of observations. We find that the anisotropic cosmic birefringence signal from any parity-violating processes is consistent with zero. The Faraday rotation from anisotropic cosmic birefringence can be compared with the equivalent quantity generated by primordial magnetic fields if they existed. The POLARBEAR nondetection translates into a 95% confidence level (C.L.) upper limit of 93 nanogauss (nG) on the amplitude of an equivalent primordial magnetic field inclusive of systematic uncertainties. This four-point correlation constraint on Faraday rotation is about 15 times tighter than the upper limit of 1380 nG inferred from constraining the contribution of Faraday rotation to two-point correlations of B-modes measured by Planck in 2015. Metric perturbations sourced by primordial magnetic fields would also contribute to the B-mode power spectrum. Using the POLARBEAR measurements of the B-mode power spectrum (two-point correlation), we set a 95% C.L. upper limit of 3.9 nG on primordial magnetic fields assuming a flat prior on the field amplitude. This limit is comparable to what was found in the Planck 2015 two-point correlation analysis with both temperature and polarization. We perform a set of systematic error tests and find no evidence for contamination. This work marks the first time that anisotropic cosmic birefringence or primordial magnetic fields have been constrained from the ground at subdegree scales.

关键词： CONSTRAINTS (Physics) BIREFRINGENCE MAGNETIC fields

来源：评论

学校读者我要写书评

暂无评论

Output feedback tracking control for spacecraft relative translation subject to input constraints and partial loss of control effectiveness

Output feedback tracking control for spacecraft relative tra...

引用

American Control Conference

作者： Lin Zhao Yingmin Jia Junping Du Jun Zhang Seventh Research Division and the Department of Systems and Control Beihang University (BUAA) Beijing 100191 China Beijing Key Laboratory of Intelligent Telecommunications Software and Multimedia School of Computer Science and Technology Beijing University of Posts and Telecommunications Beijing 100876 China School of Electronic and Information Engineering Beihang University (BUAA) Beijing 100191 China

ISBN: (纸本)9781479932757

In this paper, an adaptive output feedback tracking control scheme is proposed for spacecraft formation flying (SFF) in the presence of external disturbances, uncertain system parameters, input constraints and partial loss of control effectiveness. The proposed controller incorporates a pseudo-velocity filter to account for the unmeasured relative velocity, and the neural network (NN) technique is implemented to approximate the desired nonlinear function and bounded external disturbances. In order to guarantee that the output of the NN used in the controller is bounded by the corresponding bound of the approximated nonlinear function, a switch function is employed to generate a switching between the adaptive NN control and the robust controller. Moreover, a fault tolerant part is included in the controller to compensate the partial loss of actuator effectiveness fault. It is shown that the derived controller not only guarantees the tracking error in the closed-loop system to be uniformly ultimately bounded (UUB) but also ensures the control input can rigorously enforce actuator magnitude constraints. Simulation results are provided to demonstrate the effectiveness of the proposed method.

关键词： SFF UUB NN

来源：评论

学校读者我要写书评

暂无评论

Robust H_∞ Consensus Control of Uncertain Multi-Agent systems with Nonlinear Dynamics and Time-Varying Delays

Robust H_∞ Consensus Control of Uncertain Multi-Agent Syste...

引用

American Control Conference

作者： Ping Wang Yingmin Jia Junping Du Jun Zhang Seventh Research Division and the Department of Systems and Control Beihang University (BUAA) Beijing 100191 China Beijing Key Laboratory of Intelligent Telecommunications Software and Multimedia School of Computer Science and Technology Beijing University of Posts and Telecommunications Beijing 100876 China School of Electronic and Information Engineering Beihang University (BUAA) Beijing 100191 China

ISBN: (纸本)9781479932757

This paper is concerned with the H_∞ consensus control problem in undirected networks of autonomous agents with nonlinear dynamics, subject to parameter uncertainties and external disturbances. With the consideration of time-varying delays arising from communication among agents, a distributed protocol is proposed using the local delayed state information. Then, by defining an appropriate controlled output function, the consensus problem under the proposed protocol is converted into an H_∞ control problem. Based on robust H_∞ theory, sufficient conditions are derived to make all agents achieve consensus with desired H_∞ performance. Moreover, the feedback matrix in the proposed protocol is determined by solving two linear matrix inequalities (LMIs) with the same dimensions as a single agent. Finally, a numerical simulation is provided to demonstrate the effectiveness of our theoretical results.

关键词： Multi-agent systems Protocols Nonlinear dynamical systems Uncertain systems Linear matrix inequalities Robustness Delay effects

来源：评论

学校读者我要写书评

暂无评论

Understanding the implications of virtual machine management on processor microarchitecture design

Understanding the implications of virtual machine management...

引用

2013 IEEE International Symposium on Performance Analysis of systems and Software, ISPASS 2013

作者： Sui, Xiufeng Sun, Tao Li, Tao Zhang, Lixin Advanced Computer Systems Laboratory Institute of Computing Technology CAS Beijing China Computer Science and Technology Department University of Science and Technology of China Hefei China Dept. of Electrical and Computer Engineering University of Florida United States

ISBN: (纸本)9781467357777

Cloud computing has demonstrated tremendous capability in a wide spectrum of online services. Virtualization provides an efficient solution to the utilization of modern multicore processor systems while affording significant flexibility. The growing popularity of virtualized datacenters motivates deeper understanding of the interactions between virtual machine management and the micro-architecture behaviors of the privileged domain. We argue that these behaviors must be factored into the design of processor microarchitecture in virtualized datacenters. In this work, we use performance counters on modern servers to study the micro-architectural execution characteristics of the privileged domain while performing various VM management operations. Our study shows that today's state-of-the-art processor still has room for further optimizations when executing virtualized cloud workloads, particularly in the organization of last level caches and on-chip cache coherence protocol. Specifically, our analysis shows that: shared caches could be partitioned to eliminate interference between the privileged domain and guest domains;the cache coherence protocol could support a high degree of data sharing of the privileged domain;and cache capacity or CPU utilization occupied by the privileged domain could be effectively managed when performing management workflows to achieve high system throughput. © 2013 IEEE.

关键词： Virtualization

来源：评论

学校读者我要写书评

暂无评论

Self-assembly of skyrmion-dressed chiral nematic colloids with tangential anchoring

引用

Physical Review E 2014年第6期89卷 060502(R)-060502(R)页

作者： M. B. Pandey T. Porenta J. Brewer A. Burkart S. Čopar S. Žumer Ivan I. Smalyukh Department of Physics and Liquid Crystal Materials Research Center University of Colorado Boulder Colorado 80309 USA Department of Physics VSSD College Kanpur 208 002 India Faculty of Mathematics and Physics University of Ljubljana Jadranska 19 1000 Ljubljana Slovenia Jozef Stefan Institute Jamova 39 1000 Ljubljana Slovenia Department of Electrical Computer and Energy Engineering and Materials Science and Engineering Program University of Colorado Boulder Colorado 80309 USA Renewable and Sustainable Energy Institute National Renewable Energy Laboratory and University of Colorado Boulder Colorado 80309 USA

We describe dipolar nematic colloids comprising mutually bound solid microspheres, three-dimensional skyrmions, and point defects in a molecular alignment field of chiral nematic liquid crystals. Nonlinear optical imaging and numerical modeling based on minimization of Landau–de Gennes free energy reveal that the particle-induced skyrmions resemble torons and hopfions, while matching surface boundary conditions at the interfaces of liquid crystal and colloidal spheres. Laser tweezers and videomicroscopy reveal that the skyrmion-colloidal hybrids exhibit purely repulsive elastic pair interactions in the case of parallel dipoles and an unexpected reversal of interaction forces from repulsive to attractive as the center-to-center distance decreases for antiparallel dipoles. The ensuing elastic self-assembly gives rise to colloidal chains of antiparallel dipoles with particles entangled by skyrmions.

关键词： SKYRMIONS research LIQUID crystals MOLECULAR self-assembly PARTICLES QUANTUM entanglement

来源：评论

学校读者我要写书评

暂无评论

Smart base station antenna performance for cellular radio system

引用

Journal of engineering science and Technology Review 2013年第5期6卷 38-47页

作者： Ghayoula, R. Smida, A. Gharsallah, A. Grenier, D. Unit of Research in High Frequency Electronic Circuits and Systems Faculty of Mathematical Physical and Natural Sciences of Tunis Tunis El Manar University Campus Universitaire Tunis El Manar-2092 Tunis Tunisia Department of Electrical and Computer Engineering Laval University 1065 Avenue de la Médecine QC Canada

Adaptive array antenna technology is useful for detecting the Direction of Arrival (DOA) of signal and delay for mobile communications, where the antenna beam will automatically directed to the signal source. One method to estimate DOA and delay effectively is by using MUSIC (Multiple Signal Classification) algorithm. When the signal arrive at the antenna, the MUSIC algorithm will arrange the signal into its matrix covariance, and then perform an eigen decomposition process to produce the signal and noise subspace, and then obtain the power spectrum and delay spectrum. This paper combined the Taguchi method and MUSIC algorithm, used them as the prediction tool in designing parameters for the communication system and then constructed a set of the optimal parameter analysis flow and steps. Several adaptive beamforming criteria were discussed and a general form for the optimum array weight vector was derived that would require large amounts of computational load. Hence, it is necessary to find technique that can find optimum solution in real time. This paper will discuss the application of MUSIC algorithm for linear and circular array antenna in order to estimate the DOA and delay of various angles of elevation and azimuth. © 2013 Kavala Institute of Technology.

关键词： Multiple signal classification

来源：评论

学校读者我要写书评

暂无评论

Radar Power Amplifier Circuit and Waveform Optimization for Spectrally Confined, Reconfigurable Radar systems

Radar Power Amplifier Circuit and Waveform Optimization for ...

引用

IEEE Radar Conference

作者： Charles Baylis Josh Martin Matthew Fellows David Moon Matt Moldovan Lawrence Cohen Robert J. Marks Wireless and Microwave Circuits and Systems Program Department of Electrical and Computer Engineering Baylor University Naval Research Laboratory Radar Division

ISBN: (纸本)9781467357920

Increasingly stringent spectral spreading constraints are motivating a paradigm shift in the spectrum engineering of radar systems. Future spectrum requirements will likely dictate narrower spectral masks that will change based on geography. The desire to operate radar systems efficiently with waveforms that will provide desired detection capabilities must mesh with the need to meet spectral mask criteria. To this end, a collaborative research effort between Baylor University and the U.S. Naval research laboratory has resulted in the design of reconfigurable circuit and waveform approaches to optimize spectral confinement, power efficiency, and detection capabilities. This paper surveys the joint optimization approach and describes innovations by the authors in circuit and waveform reconfiguration that will be useful in future flexible radar transmitters.

关键词： Radar systems waveforms detection capability configurability laboratory research spectrum requirement Power amplifiers Technological Innovations Radar transmitters

来源：评论

学校读者我要写书评

暂无评论

On the performance of hybrid satellite-terrestrial cooperative networks with interferences

On the performance of hybrid satellite-terrestrial cooperati...

引用

Asilomar Conference on Signals, systems & computers

作者： Min Lin Jian Ouyang Wei-Ping Zhu National Mobile Communications Research Laboratory Southeast University Nanjing P.R. China PLA University of Science and Technology Nanjing P.R. China Institute of Signal Processing and Transmission Nanjing University of Posts and Telecommunications Nanjing P.R. China Department of Electrical and Computer Engineering Concordia University Montreal QC Canada

ISBN: (纸本)9781479982981

The paper investigates the performance of a hybrid satellite-terrestrial cooperative network (HSTCN), where some terrestrial amplify-and-forward (AF) relays are employed to assist the signal transmission from a satellite to a destination, which is corrupted by multiple co-channel interferences (CCIs). In this system, the satellite links undergo Shadowing-Rician fading while the terrestrial links experience Rayleigh fading. Specifically, by assuming that maximum ratio combining (MRC) is used at the destination, we first derive the moment generating function (MGF) of the output signal-to-interference-plus-noise ratio (SINR). With the help of MGF, we then present the analytical average symbol error rate (ASER) expression for the considered cooperative system. Moreover, to gain further insights, the asymptotic ASER analysis in terms of the diversity order and array gain is also developed. Finally, numerical results are given to demonstrate the validity of the performance analysis and the impacts of shadowing parameters, relay number and CCIs on the considered HSTCN.

关键词： Relays Satellites Signal to noise ratio Fading Cooperative systems Shadow mapping Modulation

来源：评论

学校读者我要写书评

暂无评论

DoA estimation and capacity analysis for 2D active massive MIMO systems

DoA estimation and capacity analysis for 2D active massive M...

引用

2013 IEEE International Conference on Communications, ICC 2013

作者： Zhu, Yi Liu, Lingjia Wang, Anding Sayana, Krishna Zhang, Jianzhong Charlie Department of Electrical Engineering and Computer Science University of Kansas United States Standards Research Laboratory Samsung Research America Dallas United States School of Information and Electronic Engineering Zhejiang Gongshang University China

ISBN: (纸本)9781467331227

Mobile data traffic is expected to have an exponential growth in the future. In order to meet the challenge as well as the form factor limitation on the base station, two-dimensional (2D) 'massive MIMO' has been proposed as one of the enabling technologies for future wireless systems. In 2D 'massive MIMO' systems, a base station will rely on the uplink sounding signals to figure out the downlink spatial channel information to perform MIMO precoding. Accordingly, direction-of-arrival (DoA) estimation of the underlying three-dimensional (3D) channel at the base station becomes essential for 2D 'massive MIMO' systems to realize the predicted capacity gains. In this paper, we will analyze the performance of DoA estimation based on ESPRIT methods and study its impact on the capacity of 2D 'massive MIMO' systems. To be specific, for ESPRIT-type algorithms, we will derive the closed-form expressions for the mean square errors of the elevation and azimuth angle estimations. These results will be used to obtain design intuitions for 2D antenna arrays at the base station as well as the capacity of the underlying 2D 'massive MIMO' systems. © 2013 IEEE.

关键词： MIMO systems

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：