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IEEE EMBS International Conference on Information Technology Applications in Biomedicine (ITAB)

作者： Shabnam Novin Hamid Abrishami Moghaddam Amir Masoud Sodagar Amin Mahnam Research Laboratory for Integrated Circuits and Systems (I CAS) Department of Electrical and Computer Engineering K.N. Toosi University of Technology Tehran Iran Research Laboratory for Machine Vision and Medical Image Processing (MVMIP) Department of Electrical and Computer Engineering K.N. Toosi University of Technology Tehran Iran Ecole Polytechnique de Montreal Montreal QUE Canada Department of Biomedical Engineering School of Engineering University of Isfahan Isfahan Iran

Here we present a modeling for electrical stimulation of retinal ganglion cell. This modeling can be used in epiretinal prosthesis to come up with proper electrical stimulation parameters. The model that we present is a novel one based on the anatomy of the cell. The excitation process of the electrically stimulated retinal cells is simulated in a two step procedure. In the first step the ganglion target cell is represented considering all of its compartments and in a second step the extracellular potential along the neural structure is calculated and finally the membrane voltage response to the applied stimulations is analyzed. A monopolar point electrode was positioned above the cell in an infinite and homogenous environment and the monophasic and biphasic pulses were used as stimulating current. The results show that the responses are in accordance with the values and diagrams of experimental results more than the previous models.

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High-harmonic generation using a kHz, 2.1-µm OPCPA pumped by a ps cryogenic Yb:YAG amplifier

High-harmonic generation using a kHz, 2.1-µm OPCPA pumped b...

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IEEE Photonics Conference (IPC)

作者： Kyung-Han Hong Chien-Jen Lai Shu-Wei Huang Jeffrey Moses Vasileios-Marios Gkortsas Eduardo Granados Siddharth Bhardwaj Luis E. Zapata Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics Massachusetts Institute of Technology Cambridge MA USA Basque Foundation for Science Spain

We study the cutoff extension and efficiency scaling of high-harmonic generation in Xe, Kr, and Ar using a kHz 2.1-μm OPCPA pumped by a picosecond cryogenic Yb:YAG amplifier. High-harmonic spectroscopy and propagatio... 详细信息

关键词： Laser excitation Measurement by laser beam Xenon Argon Harmonic analysis Spectroscopy Pump lasers

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A general threshold for laser-driven linear particle acceleration in infinite vacuum

A general threshold for laser-driven linear particle acceler...

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CLEO: science and Innovations, CLEO_SI 2012

作者： Wong, Liang Jie Franz X. Kartner Department of Electrical Engineering and Computer Science Research Laboratory of Electronics Massachusetts Institute of Technology 77 Massachusetts Avenue Cambridge MA 02139 United States Center for Free-Electron Laser Science DESY Department of Physics University of Hamburg Notkestraße 85 D-22607 Hamburg Germany

We derive a threshold formula for unbounded vacuum acceleration by hypothesizing that this is possible only if the field perturbs the particle relativistically in its initial rest frame. Numerical simulations support ...

ISBN: (纸本)9781557529435

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Consensus-based wireless tomography

Consensus-based wireless tomography

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International Waveform Diversity and Design Conference, WDD 2012

作者： Hu, Z. Scalzi, Gary Wicks, M.C. Qiu, R.C. Cognitive Radio Insitute Department of Electrical and Computer Engineering Center for Manufacturing Research Tennessee Technological University CookevilleTN38501 United States Air Force Research Laboratory Wright Paterson AFB OH45433 United States Sensor Systems Division University of Dayton Research Institute 300 College Park DaytonOH45469 United States

ISBN: (纸本)9781509005987

This paper, one in a series on new initiatives in wireless tomography, combines two areas: wireless communication and radio tomography. This paper discusses implementation of wireless tomography in a distributed architecture. Each sensor node in the wireless tomography system solves the local optimization problem to get the image and shares its own imaging result to all the other sensor nodes. The imaging results from all the sensor nodes will converge to the final image by iterations. Alternating direction method of multipliers (ADMM) will be explored in the paper to solve the consensus-based optimization. Consensus-based wireless tomography can distribute the computing workload among all the sensor nodes. The centralized computing engine is not needed. In this way, the wireless tomography system is scalable and robust with a large number of sensor nodes. © 2012 IEEE.

关键词： Sensor nodes

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Sensitive distance estimates technique analysis for continuously k-nearest neighbors query in multi-stream processing

International Journal of Multimedia and Ubiquitous Engineeri...

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International Journal of Multimedia and Ubiquitous engineering 2012年第2期7卷 303-308页

作者： Wang, Ling Zhou, Tie Hua Cheoi, Kyung Joo Kim, Kwang Deuk Ryu, Keun Ho Database/Bioinformatics Laboratory School of Electrical and Computer Engineering Chungbuk National University Chungbuk Korea Republic of Department of Computer Science School of Electrical and Computer Engineering Chungbuk National University Chungbuk Korea Republic of Korea Institute of Energy Research Daejeon Korea Republic of

In many real-world applications, data streams are usually collected in a decentralized manner such like sensor network, ubiquities sensor network, internet traffic analysis, and so on. In particularly, requirements for continuous, fast, high-volumes, adaptability, costly streaming data, an approximated analysis is needful for fast response to users on forward predicates. Distance estimate for both of "continuously" queries and streams is still a more challenge area because of a smaller or larger threshold selected is very easily to lead to a wrong result for continuously k-nearest neighbor queries. Therefore, we proposed a required filtering method to help to choose a well threshold of distance estimate in order to control error rates of approximated answers.

关键词： Sensor networks

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Waveform diversity for closed-loop wide-band cognitive sensing system

Waveform diversity for closed-loop wide-band cognitive sensi...

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International Waveform Diversity and Design Conference, WDD 2012

作者： Li, Xia Hu, Zhen Qiu, Robert C. Guo, Terry N. Scalzi, Gary Wicks, M.C. Cognitive Radio Insitute Department of Electrical and Computer Engineering Center for Manufacturing Research Tennessee Technological University CookevilleTN38501 United States Air Force Research Laboratory Wright Paterson AFB OH45433 United States Sensor Systems Division University of Dayton Research Institute 300 College Park DaytonOH45469 United States

ISBN: (纸本)9781509005987

This paper presents the architecture and initial measured performance of a closed-loop multi-input multi-output (MIMO) wide-band cognitive sensing system. A cognitive sensing system is one kind of cyber-physical systems that integrate the computational and physical resources for application driven tasks. In this system, computational resources dwell in the computing engine that controls the closed-loop cognitive sensing system and involves intensive computations for potential algorithms. Through this way, the transmitted waveform can be dynamically changed in response to the environment, target in the scene, and the sensing task requirement. In this paper, a real-time cognitive sensing system is first time demonstrated. The feasibility and design methodology of the system are provided. A 2 by 2 MIMO testbed with 500 MHz bandwidth, 4 GHz carrier frequency is proposed in this paper to demonstrate a bi-static radar application. The results obtained from actual experiment encourage us to explore further based on our testbed. © 2012 IEEE.

关键词： Testbeds

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Spectrum sensing in cognitive radio with robust principal component analysis

Spectrum sensing in cognitive radio with robust principal co...

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International Waveform Diversity and Design Conference, WDD 2012

作者： Hou, Shujie Qiu, Robert Browning, James P. Wicks, Michael Cognitive Radio Institute Department of Electrical and Computer Engineering Center for Manufacturing Research Tennessee Technological University CookevilleTN38505 United States Air Force Research Laboratory Wright Paterson AFB OH45433 United States Sensor Systems Division University of Dayton Research Institute 300 College Park DaytonOH45469 United States

ISBN: (纸本)9781509005987

Spectrum sensing is a cornerstone in cognitive radio. Covariance matrix based method has been widely used in spectrum sensing. As is well-known that the covariance matrix of white noise is proportional to the identity matrix which is sparse. On the other hand, the covariance matrix of signal is usually low-rank. Robust principal component analysis (PCA) has been proposed recently to recover the low-rank matrix which is corrupted by a sparse matrix with arbitrarily large magnitude non-zero entries. In this paper, robust PCA for spectrum sensing is proposed based on the sample covariance matrix. The received signal will be divided into two segments. Robust PCA will be applied to extract the low-rank matrices from the sample covariance matrices of both segments. The primary user's signal is detected if the discrepancy between the recovered low-rank matrices is smaller than a predefined threshold. The simulations are done both on the simulated and captured DTV signal. Also, the simulations that robust PCA is taken as a de-noising process for sample covariance matrix are also implemented in this paper. © 2012 IEEE.

关键词： Covariance matrix

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Enhancing the system development process performance: A value-based approach

Enhancing the system development process performance: A valu...

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22nd Annual International Symposium of the International Council on systems engineering, INCOSE 2012 and the 8th Biennial European systems engineering Conference 2012, EuSEC 2012

作者： Mastrofmi, Manuel Cantone, Giovanni Seaman, Carolyn Shull, Forrest Diep, Madeline Falessi, Davide University of Rome Tor Vergata Department of Computer Science and Systems and Production Via del Politecnico 1 00133 Rome Italy Fraunhofer Center for Experimental Software Engineering University of Maryland Baltimore County Department of Information Systems ITE. Building. 1000 Hilltop Circle Baltimore MD 21250 United States Fraunhofer Center for Experimental Software Engineering 5825 University Research Court Suite 1300 College Park MD 20740-3823 United States Simula Research Laboratory Oslo Norway University of Rome Tor Vergata Department of Computer Science Systems and Production Via del Politecnico 1 00133 Rome Italy

ISBN: (纸本)9781622769162

When planning or controlling the system development process, a project leader needs to make decisions which take into account a number of aspects, including: availability of assets and competences, previously enacted processes in the organization, certifications the system is required to obtain, standards to comply with, interactions among process activities, contextual factors and constraints, and allocated budget and schedule. In this paper we propose a value-based approach for supporting decision making. The aim is to provide supportive information for decisions related to the system verification process. This would in turn enhance the performance of system development process by supporting the decision making process for complex systems. We report both academic and industrial empirical evaluations, which demonstrate the feasibility and effectiveness of our proposal, and thus prompt us to refine and extend our approach to sub-processes other than verification. ©2012 by the authors.

关键词： Decision making

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Inter-carrier interference self-cancellation for CI/MC-CDMA system

Inter-carrier interference self-cancellation for CI/MC-CDMA ...

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International Waveform Diversity and Design Conference

作者： Xue Li Ruolin Zhou Jian Zhang Vasu Chakravarthy Zhiqiang Wu Department of Electrical Engineering Wright State University Department of Mathematics & Computer Science Texas Woman's University Air Force Research Laboratory

Multi-carrier code division multiple access (MC-CDMA) has been considered as a strong candidate for next generation wireless communication system due to its excellent performance in multi-path fading channel and simple receiver structure. Carrier Interferometry code for MC-CDMA (CI/MC-CDMA) provides better BER performance, less peak to average power ratio (PAPR) and higher design flexibility than conventional MC-CDMA systems employing Hadarmard-Walsh spreading code. However, like all the multi-carrier transmission technologies such as orthogonal frequency division multiplexing (OFDM), the inter-carrier interference (ICI) produced by the frequency offset between the transmitter and receiver local oscillators or by Doppler frequency shift due to high mobility causes significant bit error rate (BER) performance degradation in CI/MC-CDMA system. In this paper, we apply the ICI self-cancellation scheme previously proposed for OFDM system to orthogonal CI/MC-CDMA system to reduce ICI effect and improve BER performance. Unlike the traditional ICI self-cancellation scheme for OFDM which reduces the ICI at the price of lowing the transmission rate and reducing the bandwidth efficiency, we introduce a second set of orthogonal CI codes to maintain the throughput. Simulations of different leveled modulations over AWGN channel and multi-path fading channel confirmed the effectiveness and efficiency of the proposed self-embedded ICI cancellation scheme for CI/MC-CDMA system where significant BER performance gain has been observed when ICI is present.

关键词： Multicarrier code division multiple access OFDM Bit error rate Receivers AWGN channels Modulation Fading

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Attosecond photonics for optical communications

Attosecond photonics for optical communications

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Optical Fiber Communication Conference, OFC 2012

作者： Nejadmalayeri, Amir H. Grein, Matthew E. Spector, Steven J. Khilo, Anatol Peng, Michael Y. Sander, Michelle Y. Wang, Jade Benedick, Andrew J. Sorace, Cheryl M. Geis, Michael W. Willis, Matthew M. Lennon, Donna M. Yoon, Jung U. Lyszczarz, Theodore M. Ippen, Erich P. Kärtner, Franz X. Research Laboratory of Electronics Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology 77 Massachusetts Avenue Cambridge MA 02139 United States Lincoln Laboratory Massachusetts Institute of Technology 244 Wood Street Lexington MA 02420 United States Center for Free-Electron Laser Science DESY and University of Hamburg 85 Notkestrae Hamburg 22607 Germany

Recent experiments have demonstrated that low-jitter mode locked lasers enable unprecedented high-resolution high-speed analog to digital conversion. That capability may be leveraged to bring spectral efficiency of op... 详细信息

ISBN: (纸本)9781557529381

关键词： Analog to digital conversion

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