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2nd International IEEE EMBS Conference on Neural engineering, 2005

作者： Wang, Yadong Ahmar, Nayef E. Xiang, Juanjuan Ma, Ling Poeppel, David Simon, Jonathan Z. Cognitive Neuroscience of Language Laboratory University of Maryland College Park Department of Electrical and Computer Engineering University of Maryland College Park Bioengineering Program University of Maryland College Park Department of Biology University of Maryland College Park

Complex numbers appear naturally in biological systems in the context of the Fourier transform. In particular, physiological magnetic field data from whole head magneto-encephalography (MEG) is complex after a Fourier transform. The whole-head MEG Steady State Response (SSR) to a stationary modulated stimulus results in a complex magnetic field for each MEG channel, from the frequency corresponding to that of the stimulus modulation. This complex data set is used to estimate the neural current sources generating the magnetic field, naturally leading to complex current sources. We show that standard inverse methods of estimating the current sources, such as the single equivalent-current dipole, generalize to complex sources in a useful and straightforward manner. The usage and utility of the complex magnetic field and the complex neural current source are demonstrated using examples from auditory SSR experiments. © 2005 IEEE.

关键词： Equivalent circuits

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Optimal phase-tracking of the nonlinear circadian oscillator

Optimal phase-tracking of the nonlinear circadian oscillator

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2005 American Control Conference, ACC

作者： Bagheri, Neda Stelling, Jörg Doyle III, Francis J. Department of Electrical and Computer Engineering University of California Santa Barbara Santa Barbara CA 93106 United States Institute of Computational Science ETH Zentrum HRS H 28 8092 Zürich Switzerland Department of Chemical Engineering Biomolecular Science and Engineering Program University of California Santa Barbara Santa Barbara CA 93106 United States

Through investigation of transient phase characteristics, a methodology is developed to optimize the phase resetting properties of robust nonlinear biological oscillators;in particular, those of the circadian rhythm. This pacemaker is an autonomous chemical oscillator with a period close to 24 hours. Research in chronobiology indicates that light stimuli can be used to delay or advance the phase of the oscillator, allowing it to synchronize physiological processes and govern daily fluctuations in the core body. This paper proves that a circadian oscillator optimally recovers extreme phase difference (half the nominal period) within 4-days. © 2005 AACC.

关键词： Oscillators (electronic)

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Work in progress - a unifying set of experiments for digital design I

Work in progress - a unifying set of experiments for digital...

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Frontiers in Education (FIE) Conference

作者： L.A. Slivovsky B.J. Mealy A.A. Liddicoat Computer Engineering Program Electrical Engineering Department California Polytechnic State University San Louis Obispo CA USA

Continual advances in technology necessitate ongoing updates and modifications to existing digital design laboratory experiments to ensure a quality, state-of-the-art lab experience for both students and instructors. Maintenance of laboratory material in this manner can obscure the original purpose of experiments, specifically in relation to learning objectives, as changes accumulate over time. Our Digital Design I laboratory is undergoing a transformation with a focus on four areas: continuity of experiments, system integration, independence from lecture, and instructor preparation. A set of experiments with a unifying theme introduces students to modular design techniques and system integration; students combine the results of weekly experiments into a single large design at the end of the quarter. Emphasis is placed ensuring that both the individual labs and final design represent real world applications. Self contained lab experiments with accompanying teaching materials ensure minimal prep time for instructors while providing students with necessary background information to understand and complete laboratory experiments. This paper presents an outline of the new course materials, describes how this new approach relates to course learning objectives, and provides preliminary assessment results comparing student performance in lecture for lab control and experimental groups

关键词： Laboratories Design engineering Alarm systems Embedded computing Switches Education computer science Embedded system Test equipment Logic devices

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An analysis of unlicensed device operation in licensed broadcast service bands

An analysis of unlicensed device operation in licensed broad...

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IEEE International Symposium on New Frontiers in Dynamic Spectrum Access Networks, DySPAN

作者： T.X. Brown Interdisciplinary Telecommunication Program Electrical and Computer Engineering Department University of Colorado Boulder CO USA

Recent FCC proceedings have considered the notion of unlicensed device operation in licensed bands. Licensed users are concerned about harmful interference while unlicensed device manufacturers are concerned that harmful interference is an imprecise design concept. This paper addresses three elements to this debate. First, it advocates for an explicit model of harmful interference to be included in unlicensed device rules. Such a model provides explicit bounded protection to the licensed user while providing assurances and performance goals to the unlicensed device manufacturers. Second, it assesses several proposed methods for unlicensed devices to avoid licensed users and develops variants of each that can achieve the necessary accuracy. Third, it presents an analytic model for assessing harmful interference that not only provides quantitative analysis, but, also provides insight into how factors such as directional antennas, power control, and licensed channel avoidance strategies affect the aggregate interference. Further, it suggests that complex factors such as unlicensed device modulation schemes can be captured in a simple measurement. These ideas are applied to the notice of proposed rulemaking on unlicensed operation in the TV broadcast bands

关键词： Interference TV broadcasting FCC Protection Investments Telecommunication computing Virtual manufacturing Directional antennas Power control Aggregates

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Atomic Force Microscopy Probe with Integrated Loop and Shielded Leads for Micromagnetic Sensing

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MRS Online Proceedings Library 2005年第1期872卷 1-6页

作者： D. P. Lagally A. Karbassi Y. Wang C. A. Paulson D. W. van der Weide Materials Science Program University of Wisconsin-Madison Madison USA Department of Electrical and Computer Engineering University of Wisconsin-Madison Madison USA

The effort to produce an instrument that can achieve high spatial resolution, nondestructive, surface and sub-surface imaging for a variety of materials comes with many challenges. One approach, magnetic resonance-force microscopy (MRFM), lies at the nexus of two sensitive technologies: magnetic force microscopy (MFM) and magnetic resonance imaging (MRI). MFM uses a magnetic tip in a standard atomic force microscope (AFM) to obtain magnetic information about a surface. A difference in the magnetic moments of surface atoms in different regions on the surface varies the cantilever resonance. MRI, on the other hand, uses the spin states of magnetically biased atoms to differentiate between chemical species.

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Synthesis and luminescence properties of novel ZnO nanostructures: micro and nanospheres, polyhedral cages, tetra-pods, needles, tipped nanorods, nanowires and other “microphone–shaped” structures

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MRS Online Proceedings Library 2005年第1期900卷 1-6页

作者： Aurangzeb Khan Wojciech M. Jadwisienczak Martin E Kordesch Department of Physics and Astronomy and CMSS Program Ohio University Athens USA School of Electrical Engineering and Computer Science Ohio University Athens USA

Novel ZnO nanostructures such as hollow nanospheres, nano-cages, nanoneedles, tetra-pods, nanowires, aligned nanorods and nanotubes are synthesized via thermal evaporation of ZnO and graphite powder mixtures in reduced oxygen atmosphere in the presence of argon and nitrogen flows. The ZnO nanostructures, especially nanospheres, have a unique shape and are hollow inside with walls densely decorated with aligned nanowires. Photoluminescence of synthesized ZnO structures measured at 300 K exhibits a strong near band edge peak at ∼380 nm and deep level green band centered at ∼550 nm. Fabricated ZnO structures can be studied for various applications in optoelectronics and sensors.

关键词： nanostructure luminescence semiconducting

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A second order cone program.ing formulation for classifying missing data

A second order cone programming formulation for classifying ...

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18th Annual Conference on Neural Information Processing Systems, NIPS 2004

作者： Bhattacharyya, Chiranjib Pannagadatta, K.S. Smola, Alexander J. Department of Computer Science and Automation Indian Institute of Science Bangalore 560 012 India Department of Electrical Engineering Indian Institute of Science Bangalore 560 012 India Machine Learning Program National ICT Australia and ANU Canberra ACT 0200 Australia

ISBN: (纸本)0262195348

We propose a convex optimization based strategy to deal with uncertainty in the observations of a classification problem. We assume that instead of a sample (xi;yi) a distribution over (xi;y i) is specified. In particular, we derive a robust formulation when the distribution is given by a normal distribution. It leads to Second Order Cone program.ing formulation. Our method is applied to the problem of missing data, where it outperforms direct imputation.

关键词： Second-order cone program.ing

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Reduced-order model-based feedback controller design for subsonic cavity flows

Reduced-order model-based feedback controller design for sub...

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43rd AIAA Aerospace Sciences Meeting and Exhibit

作者： Yuan, X. Caraballo, E. Yan, P. Özbay, H. Serrani, A. DeBonis, J. Myatt, J.H. Samimy, M. Collaborative Center of Control Science Ohio State University United States Department of Electrical and Computer Engineering Department of Mechanical Engineering United States Bilkent Univ. Dept. of Electrical and Electronics Eng. Ankara Turkey NASA Glenn's Quiet Aircraft Technology Program United States Air Force Research Laboratory Air Vehicles Directorate WPAFB United States

This paper explores feedback controller design for cavity flows based on reduced-order models derived using Proper Orthogonal Decomposition (POD) along with Galerkin projection method. Our preliminary analysis shows that the equilibrium of the POD model is unstable and a static output feedback controller cannot stabilize it. We develop Linear Quadratic (LQ) optimal state feedback controllers and LQ optimal observers for the linearized models. The linear controllers and observers are applied to the nonlinear system using simulations. The controller robustness is numerically tested with respect to different POD models generated at different forcing frequencies. An estimation for the region of attraction of the linear controllers is also provided.

关键词： Subsonic flow

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High-power packages for phosphor-based white-light-emitting diode lamps

High-power packages for phosphor-based white-light-emitting ...

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2005 International Semiconductor Device Research Symposium

作者： Luo, Hong Kim, Jong Kyu Xi, Yangang Cho, Jaehee Sone, Cheolsoo Park, Yongjo Schubert, E. Fred Department of Physics Applied Physics and Astronomy Rensselaer Polytechnic Institute Troy NY 12180 Electrical Computer and Systems Engineering Department Rensselaer Polytechnic Institute Troy NY 12180 Photonics Program Team Samsung Advanced Institute of Technology Suwon 440-600 Korea Republic of

ISBN: (纸本)1424400848

With the rapid development of high-power white light-emitting diodes (LEDs), advances in packaging are required to further improve the device performance. In this work, an optimized packaging configuration for high power LED lamps with enhanced phosphorescence efficiency is presented based on ray-tracing simulations and experimental results. Figure 1 shows two phosphor arrangements, namely a "proximate phosphor" and a "remote phosphor" arrangement. The surface of the reflector cup is assumed to be either specular or diffuse. Three different encapsulant geometries, i.e., a "flat" (no cap), "convex" (spherical cap with height h = r/2), and "hemispherical" (h = r) top surface, are used in the simulations. Figure 2 shows phosphorescence efficiency with different packaging configurations obtained by ray-tracing simulation. The packaging configuration with remote phosphor, diffuse reflector cup and hemispherical encapsulation shows a 50% enhancement of phosphorescence efficiency compared to conventional packaging configuration. This improvement is attributed to reduced absorption of the phosphorescence by the LED chip and the reduction of deterministic optical modes trapped inside the encapsulant of remote-phosphor and diffuse reflector cup configuration. The angular dependence of the reflectivity for a diffuse Ag reflector and a specular Ag reflector is measured and shown in Figure 3. The roughened Ag reflector has a more than two orders of magnitude higher diffusely reflected power compared with the specular Ag reflector, which leads to the extraction of the trapped optical modes occurring in packaging structures with specular reflector cups. Dichromatic LED lamps comprising an ultraviolet GaN LED (λ = 400 nm) with a blue phosphor and a blue GaInN LED (λ = 470 nm) with a yellow phosphor are fabricated with different phosphor arrangements and reflector cups. The emission spectra of the reference primary LED emitters and of the dichromatic lamps operating at 20 mA are mea

关键词： Chip scale packages

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Problem-solving videos as an instructional aid for engineering education

Problem-solving videos as an instructional aid for engineeri...

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Annual Conference of Industrial Electronics Society

作者： R.M. Nelms M.L. Langford R.F. Halpin Department of Electrical & Computer Engineering Aubum University AL USA Program Evaluation and Assessment Consultants Auburn AL USA

Described in this paper is the use of problem-solving videos as an instructional aid for teaching an introductory engineering circuit analysis course. The instructor prepared step-by-step video solutions, with audio, of classroom examples, homework problems, and examination solutions. The videos were accessed through a Website; as a result, they were available to the students twenty four hour per day and seven days per week. Web usage statistics indicate that the students were using the videos extensively as they studied course materials. Student surveys indicate that they believe that the videos were improving their understanding of the course material.

关键词： Problem-solving Videos engineering education Chemical technology Internet Circuit analysis Educational technology Statistics Microcomputers engineering students

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