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2002

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Second-Order Statistical Properties Of The Wss Jakes' Fading Channel Simulator, Chengshan Xiao, Y. Rosa Zheng, N. C. Beaulieu Jan 2002

Second-Order Statistical Properties Of The Wss Jakes' Fading Channel Simulator, Chengshan Xiao, Y. Rosa Zheng, N. C. Beaulieu

Electrical and Computer Engineering Faculty Research & Creative Works

An improved Jakes' (1994) fading channel simulator was proposed by Pop and Beaulieu (see ibid., vol.49, p.699-708, Apr. 2001) to eliminate the stationarity problem occurring in Jakes' original design. In this paper, second-order statistical properties of the improved Jakes' simulator are analyzed. Consistent with Pop and Beaulieu's caution about high-order statistics of the simulator, it is proved that some second-order statistics of both the quadrature components and the envelope do not match the desired ones even if the number of sinusoids approaches infinity. Therefore, care must be taken when the simulator is employed to evaluate algorithms and systems.

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Software Engineering As A Business, Ann K. Miller, C. Ebert Jan 2002

Software Engineering As A Business, Ann K. Miller, C. Ebert

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

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Tissue Classification Through Analysis Of Gene Expression Data Using A New Family Of Art Architectures, Rui Xu, Georgios C. Anagnostopoulos, Donald C. Wunsch Jan 2002

Tissue Classification Through Analysis Of Gene Expression Data Using A New Family Of Art Architectures, Rui Xu, Georgios C. Anagnostopoulos, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

Correct classification is crucial to cancer diagnosis and treatment. We demonstrate that a new family of neural network architectures-Ellipsoid ART and ARTMAP (EA/EAM)-can cluster and classify tissues successfully through analysis of gene expression data generated by DNA microarray experiments

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Wild Turkeys In Montana| The History, Management And Future Of The Treasure State's Adopted Game Bird, John W. Hafner Jan 2002

Wild Turkeys In Montana| The History, Management And Future Of The Treasure State's Adopted Game Bird, John W. Hafner

Graduate Student Theses, Dissertations, & Professional Papers

No abstract provided.

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Wind Energy Development Issues, Joseph C. Lerner Jan 2002

Wind Energy Development Issues, Joseph C. Lerner

Graduate Student Theses, Dissertations, & Professional Papers

No abstract provided.

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Adaptive Critic Based Optimal Neurocontrol For Synchronous Generator In Power System Using Mlp/Rbf Neural Networks, Jung-Wook Park, Ganesh K. Venayagamoorthy, Ronald G. Harley Jan 2002

Adaptive Critic Based Optimal Neurocontrol For Synchronous Generator In Power System Using Mlp/Rbf Neural Networks, Jung-Wook Park, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a novel optimal neurocontroller that replaces the conventional controller (CONVC),which consists of the automatic voltage regulator (AVR) and turbine governor, to control a synchronous generator in a power system using a multilayer perceptron neural network (MLPN) and a radial basis function neural network (RBFN). The heuristic dynamic programming (HDP) based on the adaptive critic design (ACD) technique is used for the design of the neurocontroller. The performance of the MLPN based HDP neurocontroller (MHDPC) is compared with the RBFN based HDP neurocontroller (RHDPC) for small as well as large disturbances to a power system, and they are …

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Adaptive Critic-Based Neural Network Controller For Uncertain Nonlinear Systems With Unknown Deadzones, Pingan He, Jagannathan Sarangapani, S. N. Balakrishnan Jan 2002

Adaptive Critic-Based Neural Network Controller For Uncertain Nonlinear Systems With Unknown Deadzones, Pingan He, Jagannathan Sarangapani, S. N. Balakrishnan

Electrical and Computer Engineering Faculty Research & Creative Works

A multilayer neural network (NN) controller in discrete-time is designed to deliver a desired tracking performance for a class of nonlinear systems with input deadzones. This multilayer NN controller has an adaptive critic NN architecture with two NNs for compensating the deadzone nonlinearity and a third NN for approximating the dynamics of the nonlinear system. A reinforcement learning scheme in discrete-time is proposed for the adaptive critic NN deadzone compensator, where the learning is performed based on a certain performance measure, which is supplied from a critic. The adaptive generating NN rejects the errors induced by the deadzone whereas a …

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Evaluating Community Participation Within The Usfs's Stewardship Contracting Pilot Program A Comparative Study, Bobby Grillo Jan 2002

Evaluating Community Participation Within The Usfs's Stewardship Contracting Pilot Program A Comparative Study, Bobby Grillo

Graduate Student Theses, Dissertations, & Professional Papers

No abstract provided.

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An Expert System Architecture To Detect System-Level Automotive Emc Problems, Sreeniwas Ranganathan, Daryl G. Beetner, R. Wiese, Todd H. Hubing Jan 2002

An Expert System Architecture To Detect System-Level Automotive Emc Problems, Sreeniwas Ranganathan, Daryl G. Beetner, R. Wiese, Todd H. Hubing

Electrical and Computer Engineering Faculty Research & Creative Works

Improving EMC in automobiles requires methods to detect potential problems early in the design process. Issues involved in the development of a system-level automotive EMC expert system are explored. The proposed system would help identify problems with radiation and immunity, crosstalk, placement of modules, component grounding and EMC testing. The architecture of the expert system has been developed. The system architecture is designed to allow rapid analysis of automobile designs, to point out potential problems and to suggest possible solutions.

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An Improved Pnlms Algorithm, J. Benesty, Steven L. Grant Jan 2002

An Improved Pnlms Algorithm, J. Benesty, Steven L. Grant

Electrical and Computer Engineering Faculty Research & Creative Works

The proportionate normalized least mean square (PNLMS) algorithm was developed for use in network echo cancelers. In comparison to the normalized least mean square (NLMS) algorithm, PNLMS has a very fast initial convergence and tracking when the echo path is sparse. Unfortunately, when the impulse response is dispersive, the PNLMS converges much slower than NLMS. This implies that the rule proposed in PNLMS is far from optimal. In many simulations, it seems that we fully benefit from PNLMS only when the impulse response is close to a delta function. We propose a new rule that is more reliable than the …

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Exploring The Potential Of Geographic Information Systems To Convey The Historical Geography Of Battlefields (An Iwo Jima Example), Raymond C. Backstrom Jan 2002

Exploring The Potential Of Geographic Information Systems To Convey The Historical Geography Of Battlefields (An Iwo Jima Example), Raymond C. Backstrom

Graduate Student Theses, Dissertations, & Professional Papers

No abstract provided.

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Overcoming Property: Does Copyright Trump Privacy?, Julie E. Cohen Jan 2002

Overcoming Property: Does Copyright Trump Privacy?, Julie E. Cohen

Georgetown Law Faculty Publications and Other Works

This essay does not attempt to specify the privacy rights that users might assert against the purveyors of DRM systems. Instead, it undertakes a very preliminary, incomplete exploration of several questions on the "property" side of this debate. What is the relationship between rights in copyrighted works and rights in things or collections of bits embodying works? In particular, as the (popular and legal) understanding of copies of works as residing in "things" becomes largely metaphorical, how should the law construct and enforce boundedness with respect to those copies? Does the calculus of property and contract allow for consideration of …

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Full Binary Combination Schema For Floating Voltage Source Multilevel Inverters, Xiaomin Kou, Keith Corzine, Yakov L. Familiant Jan 2002

Full Binary Combination Schema For Floating Voltage Source Multilevel Inverters, Xiaomin Kou, Keith Corzine, Yakov L. Familiant

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents schema of operation for floating voltage source multilevel inverters. The primary advantage of the proposed schema is that the number of voltage levels (and thus power quality) can be increased for a given number of semiconductor devices when compared to the conventional "flying capacitor" topology. However, the new schema requires fixed floating sources instead of capacitors and therefore is more suitable for battery power applications such as electric vehicles, flexible AC transmission systems and submarine propulsion. Alternatively transformer/rectifier circuits may be used to supply the floating sources in a similar way to cascaded H-bridge inverters. Computer simulation …

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Intelligent Control Of Turbogenerator Exciter/Turbine On The Electric Power Grid To Improve Power Generation And Stability, Ganesh K. Venayagamoorthy, Ronald G. Harley, Donald C. Wunsch Jan 2002

Intelligent Control Of Turbogenerator Exciter/Turbine On The Electric Power Grid To Improve Power Generation And Stability, Ganesh K. Venayagamoorthy, Ronald G. Harley, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

A review of the applications of intelligent control to replace/augment the conventional excitation and/or turbine control of turbogenerators on the electric power grid is presented in the paper. The intelligent controller designs are based on neural networks and adaptive critic designs (ACDs). The feedback variables are completely based on local measurements from the generators. Simulations and some practical laboratory implementations on a single-machine-infinite-bus and a three-machine power system demonstrate that intelligent controllers are much more effective than the conventional PID control for improving dynamic performance and stability of the power grid under small and large disturbances. The safety margins on …

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Madrugada| [Poems], Natalie Peeterse Jan 2002

Madrugada| [Poems], Natalie Peeterse

Graduate Student Theses, Dissertations, & Professional Papers

No abstract provided.

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A New Control Strategy For The Unified Power Flow Controller, Lin Zhang, Liangying Dong, Mariesa Crow Jan 2002

A New Control Strategy For The Unified Power Flow Controller, Lin Zhang, Liangying Dong, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

The unified power flow controller (UPFC) is the most versatile among a variety of flexible AC transmission system (FACTS) devices, which can be used for power flow control, enhancement of transient stability, damping system oscillations and voltage regulation. In this paper, we propose a new PI based approach for the dynamic control of UPFC. With the new control strategy, not only the active and reactive power flow control but also the system oscillations damping can be achieved. The digital simulation results developed in MATLAB and PSCAD/EMTDC environments are presented to verify the efficiency of the proposed control algorithm.

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Menial Labor, Corey R. Palmer Jan 2002

Menial Labor, Corey R. Palmer

Graduate Student Theses, Dissertations, & Professional Papers

No abstract provided.

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Yale Rosenberg: The Scholar And The Teacher Of Jewish Law, Sherman L. Cohn Jan 2002

Yale Rosenberg: The Scholar And The Teacher Of Jewish Law, Sherman L. Cohn

Georgetown Law Faculty Publications and Other Works

In the early 1980s, when he was a young professor at the University of Houston Law Center, the author had the occasion to meet Yale Rosenberg. It was clear from their discussion that Professor Rosenberg had a strong interest in Jewish law as well as a strong knowledge base. They discussed teaching such a course at the University of Houston Law Center. Professor Rosenberg was doubtful about teaching a course in Jewish law at a secular law school, particularly one in Texas. But that conversation began a series of conversations where Yale explored in some depth the course that we …

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Speedup Of Self-Timed Digital Systems Using Early Completion, Scott C. Smith Jan 2002

Speedup Of Self-Timed Digital Systems Using Early Completion, Scott C. Smith

Electrical and Computer Engineering Faculty Research & Creative Works

An Early Completion technique is developed to significantly increase the throughput of NULL Convention self-timed digital systems without impacting latency or compromising their self-timed nature. Early Completion performs the completion detection for registration stage i at the input of the register, instead of at the output of the register as in standard NULL Convention Logic. This method requires that the single-rail completion signal from registration stage i+1 , Ko i+1 , be used as an additional input to the completion detection circuitry for registration stage i , to maintain self-timed operation. However, Early Completion does necessitate an assumption of equipotential …

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Short Stories, Robert D. Kane Jan 2002

Short Stories, Robert D. Kane

Graduate Student Theses, Dissertations, & Professional Papers

No abstract provided.

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Two Separate Continually Online-Trained Neurocontrollers For Excitation And Turbine Control Of A Turbogenerator, Ganesh K. Venayagamoorthy, Ronald G. Harley Jan 2002

Two Separate Continually Online-Trained Neurocontrollers For Excitation And Turbine Control Of A Turbogenerator, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents the design of two separate continually online trained (COT) neurocontrollers for excitation and turbine control of a turbogenerator connected to the infinite bus through a transmission line. These neurocontrollers augment/replace the conventional automatic voltage regulator and the turbine governor of a generator. A third COT artificial neural network is used to identify the complex nonlinear dynamics of the power system. Results are presented to show that the two COT neurocontrollers can control turbogenerators under steady-state as well as transient conditions and, thus, allow turbogenerators to operate more closely to their steady-state stability limits

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Whispering-Gallery Modes In Shielded Hemispherical Dielectric Resonators, Sergey Kharkovsky, Z. E. Eremenko, V. V. Kutuzov, A. E. Kogut, Yuri F. Filipov Jan 2002

Whispering-Gallery Modes In Shielded Hemispherical Dielectric Resonators, Sergey Kharkovsky, Z. E. Eremenko, V. V. Kutuzov, A. E. Kogut, Yuri F. Filipov

Electrical and Computer Engineering Faculty Research & Creative Works

The results of the numerical and experimental investigations of whispering-gallery (WG) modes in shielded hemispherical dielectric resonators are presented in this paper. It is shown that the Q factor of WG modes in the shielded resonator can be ten times much higher than the Q factor of the similar open hemispherical dielectric-resonator modes. Shielding the resonator can decrease the dimensions of both the dielectric hemisphere and resonator as a whole, saving the high-Q factor of WG modes. The usage of a cylindrical shield and local flat reflectors in the experiment provides the investigation of the high-Q factor of WG modes …

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Analysis Of A Four-Level Dc/Dc Buck Converter, Keith Corzine, J. Yuen, J. R. Baker Jan 2002

Analysis Of A Four-Level Dc/Dc Buck Converter, Keith Corzine, J. Yuen, J. R. Baker

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a four-level DC/DC buck power converter is introduced. The primary application for this converter is to regulate the center capacitor voltage in a four-level inverter system. The steady-state and average-value models for the proposed converter are developed and compared in simulation. The converter was constructed in the laboratory and verified on a four-level motor drive system. It was shown that the four-level DC/DC converter provides capacitor voltage balancing and allows higher output voltage utilization from the inverter.

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Snapshots, Christopher Fielding Porter Jan 2002

Snapshots, Christopher Fielding Porter

Graduate Student Theses, Dissertations, & Professional Papers

No abstract provided.

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A Voice Of Reason: The Products Liability Scholarship Of Gary T. Schwartz, Joseph A. Page Jan 2002

A Voice Of Reason: The Products Liability Scholarship Of Gary T. Schwartz, Joseph A. Page

Georgetown Law Faculty Publications and Other Works

Of my many fond personal memories of Gary Schwartz, the one that stands out most vividly summons from the mists of time an evening in June 1983 at Boston's Fenway Park. It was my last visit to a childhood haunt where I had seen my first professional baseball game in 1941, an occasion that marked the beginning of a lifelong passion for the national pastime. Settled into an excellent seat that faced the storied left-field wall (and brought to mind visions of the large advertisements that covered its surface before it became known as the "Green Monster”,), I began to …

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High Q Shielded Dielectric Resonator -- The Basis Of Stable Mm-Waves Generator, V. V. Kutuzov, Sergey Kharkovsky, V. A. Solodovnik, K. A. Kutuzov Jan 2002

High Q Shielded Dielectric Resonator -- The Basis Of Stable Mm-Waves Generator, V. V. Kutuzov, Sergey Kharkovsky, V. A. Solodovnik, K. A. Kutuzov

Electrical and Computer Engineering Faculty Research & Creative Works

High Q-factor whispering gallery modes which are excited in a shielded hemispherical dielectric resonator by an external signal or Gunn diode are investigated. Their application as modes of an oscillator with high frequency stability is proposed. The power of the output signal and frequency tuning of an oscillator based on the investigated resonator are measured.

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Improvement Of Power Quality In Vsi Drives, Badrul H. Chowdhury, Ravi Bantu Jan 2002

Improvement Of Power Quality In Vsi Drives, Badrul H. Chowdhury, Ravi Bantu

Electrical and Computer Engineering Faculty Research & Creative Works

The popular VSI (voltage source inverter) drives in use today are mostly PWM (pulse width modulated) drives. Harmonics produced by these drives cause heat losses, reduce the efficiency of the machine and also cause vibrations in the rotor. Active and passive filters are some of the methods to reduce the harmonics generated by these drives. A novel method is discussed which not only eliminates the 5/sup th/ harmonic but also any other negative sequence harmonics. This method, based on a reactor circuit, shows a reduction in harmonics and an improvement in the efficiency of the machine. The method can also …

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Measurement And Monitoring Of Microwave Reflection And Transmission Properties Of Cement-Based Specimens, Sergey Kharkovsky, M. F. Akay, U. C. Hasar, C. D. Atis Jan 2002

Measurement And Monitoring Of Microwave Reflection And Transmission Properties Of Cement-Based Specimens, Sergey Kharkovsky, M. F. Akay, U. C. Hasar, C. D. Atis

Electrical and Computer Engineering Faculty Research & Creative Works

The results of measurement and monitoring of reflection and transmission properties of cement-based specimens (blocks of mortar, concrete) obtained by using a simple and an inexpensive measurement system at microwave frequencies (X-band) are presented. Dependencies of the reflection and transmission coefficients on water-to-cement (w/c) ratio, preparing and curing conditions of the specimens are demonstrated. It is shown that the amplitudes of reflection and transmission coefficients, together with thickness of the specimens, determine the complex dielectric permittivity of the hardened cement-based specimens. The expected applications of the results for the determination of physical properties of cement-based materials are discussed. The causes …

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Multilevel Voltage-Source Duty-Cycle Modulation: Analysis And Implementation, Keith Corzine, J. R. Baker Jan 2002

Multilevel Voltage-Source Duty-Cycle Modulation: Analysis And Implementation, Keith Corzine, J. R. Baker

Electrical and Computer Engineering Faculty Research & Creative Works

Multilevel converters have become increasingly popular due to high power quality, high-voltage capability, low switching losses, and low electromagnetic compatibility concerns. Considering these advantages, the multilevel converter is a suitable candidate for implementation of future naval ship propulsion systems. This paper focuses on modulation techniques for the multilevel converter. In particular, a novel voltage-source method of multilevel modulation is introduced and compared to existing methods. The proposed method is discrete in nature and can therefore be readily implemented on a digital signal processor. The method is also readily extendable to any number of voltage levels. Results of experimental implementation are …

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Counterexample Of A Claim Pertaining To The Synthesis Of A Recurrent Neural Network, Xindi Cai, Donald C. Wunsch Jan 2002

Counterexample Of A Claim Pertaining To The Synthesis Of A Recurrent Neural Network, Xindi Cai, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

Recurrent neural networks have received much attention due to their nonlinear dynamic behavior. One such type of dynamic behavior is that of setting a fixed stable state. This paper shows a counterexample to the claim of A.N. Michel et al. (IEEE Control Systems Magazine, vol. 15, pp. 52-65, Jun. 1995), that "sparse constraints on the interconnecting structure for a given neural network are usually expressed as constraints which require that pre-determined elements of T [a real n×n matrix acting on a real n-vector valued function] be zero", for the synthesis of sparsely interconnected recurrent neural networks.

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