452 research outputs found

    A Virtual Classroom Via Dataconferencing: A Multi-Institutional Experience

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    This paper presents the experience of five faculty from four universities who are co-developing and team teaching courses using the world-wide web (WWW). In particular two novel power engineering courses, Flexible Control of Transmission Systems and Flexible Control of Distribuction Systems, introduce the student to the application of power electronic-based controllers, known specifically as flexible AC transmission systems (FACTS) controllers, to enhance the performance of the transmission and distribution systems in an electric power system. In order to leverage faculty expertise in the various topics included in each course, a unique partnership was formed among five faculty from the following universities: University of Arkansas, Kansas State University, University of Missouri--Rolla and Purdue University. In order to achieve the most effective presentation, in the presence of geographical, cost, time and technology constraints, the co-developers decided to pursue various distance learning strategies to link the four universities together in a live interactive virtual classroom utilizing dataconferencing software and the WWW. In this paper we address the trials and tribulations of our experience. In particular, we discuss the use of video tape technology by mail, the use of live audio and video via an integrated service digital network (ISDN) approach, and lastly, dataconferencing software in conjunction with telephone conferencing. Each of these alternative methodologies are examined in detail and are compared and contrasted from a cost and pedagogical point of view based on our experience

    Collaborative Distance Education in Power Engineering

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    This paper presents a perspective on offering shared-courses, or courses simultaneously offered at two or more universities via various distance educational frameworks. Over a three year duration, two senior/graduate level courses were jointly developed and offered to the students at the University of Missouri--Rolla, the University of Arkansas, Kansas State University, and Purdue University. This paper discusses the various distance educational technologies including two-way audio/visual via ISDN line, video-tapes, and web-based conferencing. Both instructor and student reactions to these mediums are included. Pedagogical methods appropriate for these mediums are outlined. The paper concludes with recommendations and strategies for engineering institutions who would like to course-share with other universities and industry

    A Multi-Institutional Cooperative Approach to Power Engineering Education

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    This paper describes the multi-institutional cooperative effort between the University of Missouri--Rolla, Kansas State University, and the University of Arkansas to develop two new courses in flexible power system control

    Role of Laboratory Education in Power Engineering: Is the Virtual Laboratory Feasible? Part I

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    IEEE PES sponsors a panel session in the summer power meeting in Seattle on laboratory education in power engineering. Six short papers and one full paper summarize the opinions of the panelist. This paper contains the summary of four of the presentations. The objective of the panel is to discuss the role of laboratory education in power engineering at both the graduate and undergraduate level. The question is what type of laboratory course is needed? Power electronics, electric machines, system simulation, etc? the second objective is to assess the status and value of computer based virtual laboratories. This includes the presentation of experience with virtual laboratories and a list of available tools. The teaching of power system operation can be improved using a simulation laboratory. The available simulation tools and the assessment of their values will be an important topic of the panel. The last presentation gives opposing views, arguing for the traditional laboratory us

    Phonon and plasmon excitation in inelastic electron tunneling spectroscopy of graphite

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    The inelastic electron tunneling spectrum (IETS)of highly oriented pyrolitic graphite (HOPG) has been measured with scanning tunneling spectroscopy (STS) at 6K. The observed spectral features are in very good agreement with the vibrational density of states (vDOS) of graphite calculated from first principles. We discuss the enhancement of certain phonon modes by phonon-assisted tunneling in STS based on the restrictions imposed by the electronic structure of graphite. We also demonstrate for the first time the local excitation of surface-plasmons in IETS which are detected at an energy of 40 meV.Comment: PRB rapid communication, submitte

    Conversion of electrical energy from one form to another, and its management through multichip module structures

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    The design and fabrication of a highly integrated, intelligent integral horsepower, three-phase induction motor drive based on multichip module (MCM) technology is described. A conventional three-phase induction motor is transformed into a stand-alone variable-speed drive by way of MCM technology. This solid-state controller-known as a multichip power module (MCPM)-uses known good die (KGD) to obtain minimal footprint, volume, and mass, while maximizing efficiency, reliability, and manufacturability. This is done by integrating the low-power control and high-power sections onto a single substrate. In accordance with one embodiment of the present invention, an integrated circuit assembly formed on a single substrate is capable of transforming and controlling AC power input to DC power output responsive to input signals. In accordance with another embodiment, an integrated circuit assembly on a single substrate is capable of receiving direct current power and controlling it and transforming it to alternating current power in single phase or multiphase form having variable magnitude and/or variable frequency. In accordance with a further embodiment, an integrated circuit assembly on a single substrate is capable of receiving alternating current power and controlling it and transforming it to alternating current power in single phase or multiphase form having variable magnitude and/or variable frequency

    Femoral and obturator neuropathy secondary to retroperitoneal hemorrhage the value of the ct scan

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    A man developed signs of femoral and obturator neuropathy due to spontaneous retroperitoneal hemorrhage while taking anticoagulant drugs for suspected thrombophlebitis. The hemorrhage was demonstrated by CT scan. CT scans should be used in all patients developing signs of peripheral nerve entrapment during anticoagulant therapy.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24328/1/0000595.pd

    Deterministic polarization chaos from a laser diode

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    Fifty years after the invention of the laser diode and fourty years after the report of the butterfly effect - i.e. the unpredictability of deterministic chaos, it is said that a laser diode behaves like a damped nonlinear oscillator. Hence no chaos can be generated unless with additional forcing or parameter modulation. Here we report the first counter-example of a free-running laser diode generating chaos. The underlying physics is a nonlinear coupling between two elliptically polarized modes in a vertical-cavity surface-emitting laser. We identify chaos in experimental time-series and show theoretically the bifurcations leading to single- and double-scroll attractors with characteristics similar to Lorenz chaos. The reported polarization chaos resembles at first sight a noise-driven mode hopping but shows opposite statistical properties. Our findings open up new research areas that combine the high speed performances of microcavity lasers with controllable and integrated sources of optical chaos.Comment: 13 pages, 5 figure

    Local singlets, frustration, and unconventional superconductivity in the organic charge-transfer solids

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    We suggest that superconductivity (SC) in the organic charge transfer solids (CTS) is reached from a Bond-Charge Density Wave (BCDW). We discuss an effective model for the BCDW to SC transition, an attractive U extended Hubbard Hamiltonian with repulsive nearest neighbor interaction V. We discuss experimental consequences of the theory for different classes of CTS superconductors as well as related inorganic materials.Comment: 4 pages, 2 figures, ECRYS 200

    The politicisation of evaluation: constructing and contesting EU policy performance

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    Although systematic policy evaluation has been conducted for decades and has been growing strongly within the European Union (EU) institutions and in the member states, it remains largely underexplored in political science literatures. Extant work in political science and public policy typically focuses on elements such as agenda setting, policy shaping, decision making, or implementation rather than evaluation. Although individual pieces of research on evaluation in the EU have started to emerge, most often regarding policy “effectiveness” (one criterion among many in evaluation), a more structured approach is currently missing. This special issue aims to address this gap in political science by focusing on four key focal points: evaluation institutions (including rules and cultures), evaluation actors and interests (including competencies, power, roles and tasks), evaluation design (including research methods and theories, and their impact on policy design and legislation), and finally, evaluation purpose and use (including the relationships between discourse and scientific evidence, political attitudes and strategic use). The special issue considers how each of these elements contributes to an evolving governance system in the EU, where evaluation is playing an increasingly important role in decision making
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