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International Conference on Advanced Information Networking and Applications (AINA)

作者： Salah Zahed Irfan Awan Andrea Cullen M. Younas The Higher Institute of Comprehensive Professions Ghadames Libya School of Electrical Engineering and Computer Science University of Bradford Bradford UK Department of Computing and Communication Technologies Oxford Brookes University Oxford UK

One of the major challenges of Cognitive Radio (CRNs) is the spectrum handoff issue. Spectrum handoff happens when a Primary Users (PUs) appears in a spectrum band that is occupied by a Secondary User (SU). In such a case, SU should empty this spectrum band and perform a handoff procedure and search for an available free one. This process will be continued until the SU completes its data transmission. To avoid multiple spectrum handoffs, the spectrum handoff procedure should be performed in the unlicensed channels rather than the licensed channels. Thus, the number of handoffs can be reduced as no more spectrum handoffs will occur since all users have priority in this type of spectrum channel. This technique will help secondary users' QoS from degradation. This paper proposes a prioritized spectrum handoff decision scheme in a mixture spectrum environment of unlicensed and licensed channels, in order to reduce the handoff delay. The licensed channels in the proposed scheme have been modelled using a pre-emptive resume priority (PRP) M/M/C queue. In contrast, the unlicensed channels have been modelled using an M/M/C retrial priority queue. In order to examine the performance of the implemented model, the handoff and new SUs are considered with equal and different priorities. Experimental results show that the prioritized handoff scheme outperforms the other scheme in terms of average handoff delay under various traffic arrival rates as well as the number of licensed and unlicensed channels used.

关键词： Delays Sensors Cognitive radio Quality of service Mathematical model Orbits

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Is quantum capacitance in graphene a potential hurdle for device scaling？

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Nano Research 2014年第4期7卷 453-461页

作者： Jaeho Lee Hyun-Jong Chung David H. Seo Jaehong Lee Hyungcheol Shin Sunae Seo Seongjun Park Sungwoo Hwang Kinam Kim Samsung Advanced Institute of Technology Samsung Electronics Yongin-Si Gyeonggi-Do 446-712 Korea Inter-University Semiconductor Research Center (ISRC) School of Electrical Engineering and Computer Science Seoul National University Seoul 151-742 Korea Division of Quantum Phases and Devices Department of Physics Konkuk University Seou1143-701 Korea Semiconductor R&D Center Somsung Electronics Hwasung-City Gyeonggi-Do 446-711 Korea Department of Physics Sejong University Seou1143-74 7 Korea Memory Division Samsung Electronics Hwasung-City Gyeonggi-Do 446-711 Korea

Transistor size is constantly being reduced to improve performance as well as power consumption. For the channel length to be reduced, the corresponding gate dielectric thickness should also be reduced. Unfortunately, graphene devices are more complicated due to an extra capacitance called quantum capacitance （CQ） which limits the effective gate dielectric reduction. In this work, we analyzed the effect of CQ on device-scaling issues by extracting it from scaling of the channel length of devices. In contrast to previous reports for metal-insulator- metal structures, a practical device structure was used in conjunction with direct radio-frequency field-effect transistor measurements to describe the graphene channels. In order to precisely extract device parameters, we reassessed the equivalent circuit, and concluded that the on-state model should in fact be used. By careful consideration of the underlap region, our device modeling was shown to be in good agreement with the experimental data. CQ contributions to equivalent oxide thickness were analyzed in detail for varying impurity concentrations in graphene. Finally, we were able to demonstrate that despite contributions from CQ, graphene＇s high mobility and low-voltage operation allows for ~raphene channels suitable for next generation transistors.

关键词： graphene equivalent circuit quantum capacitance intrinsic delay

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In-plane surface plasmonics integrated with thz quantum cascade lasers for high collimation

In-plane surface plasmonics integrated with thz quantum casc...

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2014 Conference on Lasers and Electro-Optics, CLEO 2014

作者： Liang, Guozhen Dupont, Emmanuel Fathololoumi, Saeed Wasilewski, Zbigniew R. Ban, Dayan Fung Yu, Siu Li, Lianhe Davies, Alexander Giles Linfield, Edmund Chun Liu, Hui Wang, Qi Jie School of Electrical and Electronic Engineering Nanyang Technological University 50 Nanyang Avenue Singapore Singapore National Research Council Bldg. M-50 1200 Montreal Rd OttawaON Canada Department of Electrical and Computer Engineering Waterloo Institute for Nanotechnology University of Waterloo 200 University Ave. West WaterlooON Canada Department of Applied Physics Hong Kong Polytechnic University Kowloon Hong Kong School of Electronic and Electrical Engineering University of Leeds Leeds United Kingdom Key Laboratory of Artificial Structures and Quantum Control Department of Physics Shanghai Jiao Tong University Shanghai China CDPT Centre for Disruptive Photonic Technology School of Physical and Mathematical Sciences Nanyang Echnological University Singapore Singapore

We report planar integration of tapered Terahertz (THz) quantum cascade lasers (QCLs) with spoof surface plasmon (SSP) structures. The SSP structure consists of one plasmonic coupler and periodically arranged scatters. The resulting surface-emitting THz beam is highly collimated with a beam divergence as narrow as 3.6°×9.7°. As the beam divergence is inverse proportional to the light emission area, this low divergence indicates a good waveguiding property of the SSP structure, while the low optical background of the beam implies a high coupling efficiency of the THz wave from the laser cavity to the SSPs. Since all the structures are in-plane, this scheme provides a promising platform where the well-established SP techniques can be employed to engineer the THz QCL beam with high flexibilities. © 2014 Optical Society of America.

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Routing and channel assignment in wireless cooperative networks

Routing and channel assignment in wireless cooperative netwo...

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International Wireless Communications and Mobile computing Conference, IWCMC

作者： Kun Xie Hui Li Xin Wang Shiming He Jigang Wen Mohsen Guizani College of Computer Science and Electronics Engineering Hunan University Changsha China Department of Electrical and Computer Engineering State University of New York at Stony Brook USA Institute of Computing Technology Chinese Academy of Sciences Beijing China Qatar University Doha Qatar

In recent years, cooperative communication has attracted researchers' attention as it showed a good capability to increase network performance. On the other hand, a cooperative transmission may cause more interference. This can cause difficulty in achieving cooperative diversity gain in multi-flow and multi-hop networks. In this paper, we propose a novel interference aware-cooperative-routing metric which will lead to creating a new scheme for cooperative routing and channel assignment in multi-flow and multi-hop networks. Then, we show through preliminary simulation results, by investigating the impact of the node density and impact of the flow number, that the proposed scheme minimizes interference while achieving maximum cooperative diversity gain.

关键词： Wireless communication Cooperative systems Relays Receivers Interference Routing

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Topologically Robust Transport of Photons in a Synthetic Gauge Field

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Physical Review Letters 2014年第8期113卷 087403-087403页

作者： S. Mittal J. Fan S. Faez A. Migdall J. M. Taylor M. Hafezi Joint Quantum Institute NIST/University of Maryland College Park Maryland 20742 USA Department of Electrical and Computer Engineering University of Maryland College Park Maryland 20742 USA Huygens-Kamerlingh Onnes Laboratorium Universiteit Leiden Postbus 9504 2300 RA Leiden The Netherlands

Electronic transport is localized in low-dimensional disordered media. The addition of gauge fields to disordered media leads to fundamental changes in the transport properties. We implement a synthetic gauge field for photons using silicon-on-insulator technology. By determining the distribution of transport properties, we confirm that waves are localized in the bulk and localization is suppressed in edge states. Our system provides a new platform for investigating the transport properties of photons in the presence of synthetic gauge fields.

关键词： ELECTRON kinetic energy LIGHT quantization PHOTOCHEMICAL equivalence law EINSTEIN-Podolsky-Rosen experiment PHOTON-lepton interactions

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A Reference Architectural Pattern: Component-Based Scheduling System for Heterogeneous computing Environment

A Reference Architectural Pattern: Component-Based Schedulin...

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Annual Global Online Conference on Information and computer Technology (GOCICT)

作者： Absalom E. Ezugwu Marc E. Frincu Sahalu B. Junaidu Department of Computer Science Federal University Lafia Nasarawa Lafia Nigeria Department of Electrical Engineering University of Southern California Los Angeles USA Institute of Computing and ICT Ahmadu Bello University Zaria Zaria Nigeria

The paper presents a conceptual design pattern for a component-based scheduling framework for several classes of multi-component applications. In addition, we propose an object oriented reference architecture, which guides the design of a general purpose scheduling system inside a wide-area heterogeneous computing environment or meta-systems. The heterogeneity nature of today's application and computing environment, make this a challenging problem. However, the current off-the-shelf scheduling software can hardly cope with the rapid innovation in distributed computing applications frameworks, and therefore, the need for an adequate scheduling system with diversified features, and capability for robustness and optimal scheduling efficiency. The design goal is based on the assumption that effective scheduling of multi-component applications is possible, if only sufficient application and system resource cost information would be provided to the scheduler prior to scheduling processes.

关键词： Processor scheduling computer architecture Optimal scheduling Resource management Dynamic scheduling Servers

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Terahertz Detector Based on a p-n Junction Film of Aligned Carbon Nanotubes

Terahertz Detector Based on a p-n Junction Film of Aligned C...

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CLEO: Applications and Technology, CLEO_AT 2014

作者： He, Xiaowei Fujimura, Naoki Erickson, Kristopher Talin, A. Alec Zhang, Qi Gao, Weilu Kawano, Yukio Hauge H., Robert Leonard, Francois Kono, Junichiro Department of Electrical and Computer engineering Rice University Houston TX 77005 United States Quantum Nano-electronics Research Center Department of PhysicalElectronics Tokyo Institute of Technology Tokyo 152-8552 Japan Sandia National Laboratories Livermore CA 94551 United States Department of Chemistry Rice University Houston TX 77005 United States King Abdulaziz University Saudi Arabia Department of Physics and Astronomy and Department of Materials Science and NanoEngineering Rice University Houston TX 77005 United States

We have developed a room temperature, broadband, and polarization-sensitive terahertz detector based on a p-n junction film of highly aligned and ultralong carbon nanotubes. Direct thermoelectric measurements demonstr... 详细信息

ISBN: (纸本)9781557529992

关键词： Carbon nanotubes

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Optimal scheduling of single-arm multi-cluster tools with two-space buffering modules

Optimal scheduling of single-arm multi-cluster tools with tw...

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IEEE International Conference on Automation Science and engineering (CASE)

作者： FaJun Yang NaiQi Wu Yan Qiao MengChu Zhou Department of Industrial Engineering Guangdong University of Technology Guangzhou China Institute of Systems Engineering Macau University of Science and Technology Macau Key Laboratory of Embedded System and Service Computing Tongji University Shanghai China Department of Electrical and Computer Engineering New Jersey Institute of Technology Newark NJ USA

A multi-cluster tool is composed of a number of single-cluster tools linked by buffering modules. The capacity of a buffering module can be one or two. Aiming at finding an optimal one-wafer cyclic schedule, this work explores the effect of two-space buffering modules on the performance of a multi-cluster tool. The tool is modeled by a kind of Petri nets. The dynamic behavior of robot waiting and tasks, process modules, and buffers is well captured by the net model. With the model, this work shows that there is always a one-wafer cyclic schedule that reaches the lower bound of the cycle time of a process-dominant tool. Furthermore, a constant-time algorithm is revealed to find such a schedule for the first time for such multi-cluster tools. An illustrative example is given to show the application and power of this new method.

关键词： Schedules Robot kinematics Firing Semiconductor device modeling Fires Load modeling

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Performance characterization of heterogeneous distributed commodity cluster resources

Performance characterization of heterogeneous distributed co...

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International Conference on Adaptive Science & Technology (ICAST)

作者： Absalom E. Ezugwu Marc E. Frincu Sahalu B. Junaidu Department of Computer Science Federal University Lafia Lafia-Nasarawa Nigeria Department of Electrical Engineering University of Southern California Los Angeles USA Institute of Computing and ICT Ahmadu Bello University Zaria Zaria-Kaduna Nigeria

While distributed computing systems which generally involve the aggregation of geographically distributed heterogeneous resources can in principle be used as computing platform, in practice, the discovery and selection of quality resources that satisfy user's application requirements remain an issue that is difficult to address. In this paper, we represent the performance of a computational cluster as a regression model that can be used to fine-tune the selection of suitable cluster resources. A study on the performance of distributed systems with respect to particular variations in parameters is presented. Our objective is to use a measurement-based evaluation technique to characterize the specific performance contribution of the individual cluster resource configurations. In the process we identify the key primary parameters (or factors) that should be considered when selecting and allocating a computational node for user application execution.

关键词： Bandwidth Computational modeling Processor scheduling Resource management Data mining Aggregates Throughput

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Low-temperature illumination and annealing of ultrahigh quality quantum wells

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Physical Review B 2014年第12期90卷 121405(R)-121405(R)页

作者： M. Samani A. V. Rossokhaty E. Sajadi S. Lüscher J. A. Folk J. D. Watson G. C. Gardner M. J. Manfra Quantum Matter Institute University of British Columbia Vancouver British Columbia Canada V6T1Z4 Department of Physics and Astronomy University of British Columbia Vancouver British Columbia Canada V6T1Z4 Department of Physics and Astronomy Purdue University West Lafayette Indiana 47907 USA Birck Nanotechnology Center Purdue University West Lafayette Indiana 47907 USA School of Materials Engineering Purdue University West Lafayette Indiana 47907 USA School of Electrical and Computer Engineering Purdue University West Lafayette Indiana 47907 USA

The effects of low-temperature illumination and annealing on fractional quantum Hall (FQH) characteristics of a GaAs/AlGaAs quantum well are investigated. Illumination alone, below 1 K, decreases the density of the two-dimensional electron gas (2DEG) electrons by more than an order of magnitude and resets the sample to a repeatable initial state. Subsequent thermal annealing at a few Kelvin restores the original density and dramatically improves FQH characteristics. A reliable illumination and annealing recipe is developed that yields an energy gap of 600 mK for the 5/2 state.

关键词： quantum Hall effect LOW temperature research quantum wells GALLIUM arsenide GALLIUM aluminum arsenide ELECTRON gas research ENERGY gaps (Physics)

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