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Multiple Scattering Of Light In Inhomogeneous Media And Applications, Claudia Mujat Jan 2004

Multiple Scattering Of Light In Inhomogeneous Media And Applications, Claudia Mujat

Electronic Theses and Dissertations

Light scattering-based techniques are being developed for non-invasive diagnostics of inhomogeneous media in various fields, such as medicine, biology, and material characterization. However, as most media of interest are highly scattering and have a complex structure, it is difficult to obtain a full analytical solution of the scattering problem without introducing approximations and assumptions about the properties of the system under consideration. Moreover, most of the previous studies deal with idealized scattering situations, rarely encountered in practice. This dissertation provides new analytical, numerical, and experimental solutions to describe subtle effects introduced by the properties of the light sources, and by …

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Evolving Models From Observed Human Performance, Hans Karl Gustav Fernlund Jan 2004

Evolving Models From Observed Human Performance, Hans Karl Gustav Fernlund

Electronic Theses and Dissertations

To create a realistic environment, many simulations require simulated agents with human behavior patterns. Manually creating such agents with realistic behavior is often a tedious and time-consuming task. This dissertation describes a new approach that automatically builds human behavior models for simulated agents by observing human performance. The research described in this dissertation synergistically combines Context-Based Reasoning, a paradigm especially developed to model tactical human performance within simulated agents, with Genetic Programming, a machine learning algorithm to construct the behavior knowledge in accordance to the paradigm. This synergistic combination of well-documented AI methodologies has resulted in a new algorithm that …

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Analysis And Modeling Of The Eds Maglev System Based On The Halbach Permanent Magnet Array, Qinghua Han Jan 2004

Analysis And Modeling Of The Eds Maglev System Based On The Halbach Permanent Magnet Array, Qinghua Han

Electronic Theses and Dissertations

Electro-dynamic suspension (EDS) Magnetic levitation (Maglev) with its advantage in maintenance, safety, efficiency, speed, and noise is regarded as a leading candidate for the next generation transportation / space launch assist system. The Halbach array due to its unique magnetic field feature has been widely used in various applications. The EDS system using Halbach arrays leads to the potential EDS system without super-conductor (SC) technology. In this thesis, the Halbach array magnetic field and the dynamics of a novel Halbach array EDS Maglev system were considered. The practical Halbach array magnetic field was analyzed using both a Fourier series approach …

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Fpga-Based Design Of A Maximum-Power-Point Tracking System For Space A, Todd Persen Jan 2004

Fpga-Based Design Of A Maximum-Power-Point Tracking System For Space A, Todd Persen

Electronic Theses and Dissertations

Satellites need a source of power throughout their missions to help them remain operational for several years. The power supplies of these satellites, provided primarily by solar arrays, must have high efficiencies and low weights in order to meet stringent design constraints. Power conversion from these arrays is required to provide robust and reliable conversion which performs optimally in varying conditions of peak power, solar flux, and occlusion conditions. Since the role of these arrays is to deliver power, one of the principle factors in achieving maximum power output from an array is tracking and holding its maximum-power point. This …

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Low Power Cmos Circuit Design And Reliability Analysis For Wireless Me, Md Anwar Sadat Jan 2004

Low Power Cmos Circuit Design And Reliability Analysis For Wireless Me, Md Anwar Sadat

Electronic Theses and Dissertations

A sensor node 'AccuMicroMotion' is proposed that has the ability to detect motion in 6 degrees of freedom for the application of physiological activity monitoring. It is expected to be light weight, low power, small and cheap. The sensor node may collect and transmit 3 axes of acceleration and 3 axes of angular rotation signals from MEMS transducers wirelessly to a nearby base station while attached to or implanted in human body. This dissertation proposes a wireless electronic system-on-a-single-chip to implement the sensor in a traditional CMOS process. The system is low power and may operate 50 hours from a …

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Hybrid And Hierarchical Image Registration Techniques, Dongjiang Xu Jan 2004

Hybrid And Hierarchical Image Registration Techniques, Dongjiang Xu

Electronic Theses and Dissertations

A large number of image registration techniques have been developed for various types of sensors and applications, with the aim to improve the accuracy, computational complexity, generality, and robustness. They can be broadly classified into two categories: intensity-based and feature-based methods. The primary drawback of the intensity-based approaches is that it may fail unless the two images are misaligned by a moderate difference in scale, rotation, and translation. In addition, intensity-based methods lack the robustness in the presence of non-spatial distortions due to different imaging conditions between images. In this dissertation, the image registration is formulated as a two-stage hybrid …

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Polarimetric Characterization Of Random Electromagnetic Beams And Applications, Mircea Mujat Jan 2004

Polarimetric Characterization Of Random Electromagnetic Beams And Applications, Mircea Mujat

Electronic Theses and Dissertations

Polarimetry is one of the principal means of investigating the interaction of light with matter. Theoretical models and experimental techniques are presented in this dissertation for polarimetric characterization of random electromagnetic beams and of signatures of random media in different scattering regimes and configurations. The degree of polarization rather than the full description of the state of polarization is of interest in multiple scattering and free space propagation where the statistical nature and not the deterministic component of light bears the relevant information. A new interferometric technique for determining the degree of polarization by measuring the intensity fluctuations in a …

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Quadratic Spatial Soliton Interactions, Ladislav Jankovic Jan 2004

Quadratic Spatial Soliton Interactions, Ladislav Jankovic

Electronic Theses and Dissertations

Quadratic spatial soliton interactions were investigated in this Dissertation. The first part deals with characterizing the principal features of multi-soliton generation and soliton self-reflection. The second deals with two beam processes leading to soliton interactions and collisions. These subjects were investigated both theoretically and experimentally. The experiments were performed by using potassium niobate (KNBO3) and periodically poled potassium titanyl phosphate (KTP) crystals. These particular crystals were desirable for these experiments because of their large nonlinear coefficients and, more importantly, because the experiments could be performed under non-critical-phase-matching (NCPM) conditions. The single soliton generation measurements, performed on KNBO3 by launching the …

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Dispersion-Managed Breathing-Mode Semiconductor Mode-Locked Ring Laser, Bojan Resan Jan 2004

Dispersion-Managed Breathing-Mode Semiconductor Mode-Locked Ring Laser, Bojan Resan

Electronic Theses and Dissertations

A novel dispersion-managed breathing-mode semiconductor mode-locked ring laser is developed. The "breathing-mode" designation derives from the fact that intracavity pulses are alternately stretched and compressed as they circulate around the ring resonator. The pulses are stretched before entering the semiconductor gain medium to minimize the detrimental strong integrating self-phase modulation and to enable efficient pulse amplification. Subsequently compressed pulses facilitate bleaching the semiconductor saturable absorber. The intracavity pulse compression ratio is higher than 50. Down chirping when compared to up chirping allows broader mode-locked spectra and shorter pulse generation owing to temporal and spectral semiconductor gain dynamics. Pulses as short …

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Design And Implementation Of A 3d Computer Game Controller Using Inertial Mems Sensors, Ali Pezeshk Jan 2004

Design And Implementation Of A 3d Computer Game Controller Using Inertial Mems Sensors, Ali Pezeshk

Dissertations, Master's Theses and Master's Reports - Open

Though 3D computer graphics has seen tremendous advancement in the past two decades, most available mechanisms for computer interaction in 3D are high cost and targeted for industry and virtual reality applications. Recent advances in Micro-Electro-Mechanical-System (MEMS) devices have brought forth a variety of new low-cost, low-power, miniature sensors with high accuracy, which are well suited for hand-held devices. In this work a novel design for a 3D computer game controller using inertial sensors is proposed, and a prototype device based on this design is implemented. The design incorporates MEMS accelerometers and gyroscopes from Analog Devices to measure the three …

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Luminescence In Zno, Jin Xu Jan 2004

Luminescence In Zno, Jin Xu

Theses and Dissertations

As a wide band semiconductor with a large binding energy (about 60meV), ZnO is a promising candidate semiconductor material for the next generation of optoelectronic , light emission or high power and high frequency devices. In order to make electrical device from ZnO, it is necessary to investigate optical properties of ZnO.In this thesis, PL setup and the properties of ZnO are introduced briefly and the optical properties of ZnO are investigated in detail. Temperature dependence of PL spectra of ZnO are measured and analyzed. Sharp emission line of PL spectra of rare earth (RE) doped ZnO are also investigated.

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Effect Of Stochastic Dead Space On Noise In Avalanche Photodiodes, Oh-Hyun Kwon, Majeed M. Hayat, Joe C. Campbell, Bahaa E.A. Saleh, Malvin Carl Teich Jan 2004

Effect Of Stochastic Dead Space On Noise In Avalanche Photodiodes, Oh-Hyun Kwon, Majeed M. Hayat, Joe C. Campbell, Bahaa E.A. Saleh, Malvin Carl Teich

Electrical and Computer Engineering Faculty Research and Publications

A stochastic dead-space model for impact ionization is developed and used to study the effect of the soft nature of the ionization capability of carriers on the excess noise factor of avalanche photodiodes. The proposed model is based on the rationale that the gradual, or soft, transition in the probability density function (PDF) for the distance from birth to impact ionization can be viewed as that resulting from uncertainty in the dead space itself. The resulting soft PDF, which is parameterized by a tunable softness parameter, is used to establish the limitations of the existing hard-threshold ionization models in ultrathin …

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A Discrete-Time Model For Triply Selective Mimo Rayleigh Fading Channels, Chengshan Xiao, Jingxian Wu, Sang-Yick Leong, Y. Rosa Zheng, Khaled Ben Letaief Jan 2004

A Discrete-Time Model For Triply Selective Mimo Rayleigh Fading Channels, Chengshan Xiao, Jingxian Wu, Sang-Yick Leong, Y. Rosa Zheng, Khaled Ben Letaief

Electrical and Computer Engineering Faculty Research & Creative Works

A statistical discrete-time model is proposed for simulating wideband multiple-input multiple-output (MIMO) fading channels which are triply selective due to angle spread, Doppler spread, and delay spread. The new discrete-time MIMO channel model includes the combined effects of the transmit filter, physical MIMO multipath channel fading, and receive filter, and it has the same sampling period as that of the MIMO receiver. This leads to very efficient simulation of physical continuous-time MIMO channels. A new method is also presented to efficiently generate the MIMO channel stochastic coefficients. The statistical accuracy of the discrete-time MIMO channel model is rigorously verified through …

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Characterization Of Human Metal Esd Reference Discharge Event And Correlation Of Generator Parameters To Failure Levels-Part I: Reference Event, Ramachandran Chundru, David Pommerenke, Kai Wang, Thomas Van Doren, Jiu Sheng Huang, Federico Centola Jan 2004

Characterization Of Human Metal Esd Reference Discharge Event And Correlation Of Generator Parameters To Failure Levels-Part I: Reference Event, Ramachandran Chundru, David Pommerenke, Kai Wang, Thomas Van Doren, Jiu Sheng Huang, Federico Centola

Electrical and Computer Engineering Faculty Research & Creative Works

Electrostatic discharge (ESD) generators are used for testing the robustness of electronics toward ESD. Most generators are built in accordance with the IEC 61000-4-2 specifications. Using only a few parameters, this standard specifies the peak current, the rise time and the falling edge. Lacking a transient field specification, test results vary depending on which generator is used, even if the currents are quite similar. Such a specification is needed to improve the test repeatability. As for the current, the specification should be based on a reference human metal ESD event. While keeping the presently set peak current and rise time …

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Electrical Breakdown In Polar Liquids, Shu Xiao Jan 2004

Electrical Breakdown In Polar Liquids, Shu Xiao

Electrical & Computer Engineering Theses & Dissertations

Hydrodynamic processes following the electrical breakdown in polar liquids, mainly water and propylene carbonate, are studied with electrical pulse-probe systems and optical diagnostics including shadowgraphy and Schlieren techniques. The dielectric strength of water in a repetitively pulsed power system is found to be 750 kV/cm and 650 kV/cm for pulses of 200 nanosecond and 8 microsecond duration, respectively. For energies less than 1 J, the discharge plasma decays in approximately one microsecond. The mechanical effect created by the expanding plasma is a shock wave which has an initial pressure of 1 GPa and decays within approximately 5 microseconds. The observed …

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Cmos Digital Pixel Sensor Array With Time Domain Analogue To Digital Conversion, Alistair J. Kitchen Jan 2004

Cmos Digital Pixel Sensor Array With Time Domain Analogue To Digital Conversion, Alistair J. Kitchen

Theses: Doctorates and Masters

This thesis presents a digital pixel sensor array, which is the first stage of an ongoing project to produce a CMOS image sensor with on-chip image processing. The analogue to digital conversion is performed at the pixel level, with the result stored in pixel memory. This architecture allows fast, reliable access to the image data and simplifies the integration of the image array and the processing logic. Each pixel contains a photodiode sensor, a comparator, memory and addressing logic. The photodiode sensor operates in integrating mode, where the photodiode junction capacitance is first charged to an initial voltage, and then …

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Neural Network Based Classification Of Road Pavement Structures, V. Venayagamoorthy, D. Allopi, Ganesh K. Venayagamoorthy Jan 2004

Neural Network Based Classification Of Road Pavement Structures, V. Venayagamoorthy, D. Allopi, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

Roads have formed the basic infrastructure of commerce since flints and other tools and artifacts were first exchanged along the trade routes of prehistory. Roadways are very large, in volume, in extent, and in value. They also wear out, and their useful life is directly proportional to their initial strength and inversely proportional to the number of heavy goods vehicles using them. Therefore, the increasing complexity of road transportation needs advanced techniques for effective design of pavements. This paper proposes an intelligent technique using neural networks to classify different types of road pavement structures, which is essential in estimating bearing …

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Learning To Learn-Concepts In A First Power Engineering Course, Badrul H. Chowdhury Jan 2004

Learning To Learn-Concepts In A First Power Engineering Course, Badrul H. Chowdhury

Electrical and Computer Engineering Faculty Research & Creative Works

Three well-known and widely accepted concepts in educational psychology are revisited. These are "inventory of learning styles," "taxonomy of educational objectives," and "metacognition." Relationships among these concepts are highlighted. Often, a student can develop his (or her) own learning style by the process of metacognition. Ideas are borrowed from these concepts for use in a first-level power systems course. It is beyond a doubt that both cognitive and metacognitive skills are necessary for students to succeed in any course. While a semester-long power systems course leaves little time for critical thinking and passive reflection for students, certain activities may very …

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Cause And Effects Of Voltage Collapse -- Case Studies With Dynamic Simulations, Feng Dong, Mariesa Crow, Badrul H. Chowdhury, Levent Acar Jan 2004

Cause And Effects Of Voltage Collapse -- Case Studies With Dynamic Simulations, Feng Dong, Mariesa Crow, Badrul H. Chowdhury, Levent Acar

Electrical and Computer Engineering Faculty Research & Creative Works

Voltage collapse studies are made to gain an insight into mechanisms that drive a system into collapse. The inter-play of generator controls in local and external areas are explored. Simulations are carried out on a medium sized network by a transient dynamic simulation program. Simulation results help to better understand remediation strategies. The time dependent characteristics of corrective controls are investigated.

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Space-Time Fading Correlation Functions Of A 3-D Mimo Channel Model, Sang-Yick Leong, Y. Rosa Zheng, Chengshan Xiao Jan 2004

Space-Time Fading Correlation Functions Of A 3-D Mimo Channel Model, Sang-Yick Leong, Y. Rosa Zheng, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

Space-time correlation functions between the links of MIMO Rayleigh fading channels are derived using a new three-dimensional (3-D) cylinder scattering model. Closed form, mathematically tractable formulas are obtained for the space-time correlation functions for general MIMO systems where the base station and mobile station antennas may be arranged in 3-D space. It is shown that the correlation functions computed by the 3-D cylinder model are of significant difference than those of the conventional 2-D Clarke''s isotropic scattering model for vertically placed antennas. The general formulas of the correlation functions includes the 2-D Clarke''s model and the 3-D SIMO, MISO models …

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Adaptive Critic Neural Network-Based Object Grasping Control Using A Three-Finger Gripper, Gustavo Galan, Jagannathan Sarangapani Jan 2004

Adaptive Critic Neural Network-Based Object Grasping Control Using A Three-Finger Gripper, Gustavo Galan, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

Grasping of objects has been a challenging task for robots. The complex grasping task can be defined as object contact control and manipulation subtasks. In this paper, object contact control subtask is defined as the ability to follow a trajectory accurately by the fingers of a gripper. The object manipulation subtask is defined in terms of maintaining a predefined applied force by the fingers on the object. A sophisticated controller is necessary since the process of grasping an object without a priori knowledge of the object's size, texture, softness, gripper, and contact dynamics is rather difficult. Moreover, the object has …

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Mixing Electromagnetic And Electrical Circuit Simulations, W. C. Chew, Y. H. Chu, L. (Lijun) J. Jiang, I. T. Chiang, Y. C. Pan, J. S. Zhao Jan 2004

Mixing Electromagnetic And Electrical Circuit Simulations, W. C. Chew, Y. H. Chu, L. (Lijun) J. Jiang, I. T. Chiang, Y. C. Pan, J. S. Zhao

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

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Synthesis Of Reversible Circuits From A Subset Of Muthukrishnan-Stroud Quantum Realizable Multi-Valued Gates, Marek Perkowski, Nicholas Denler, Bruce Yen, Pawel Kerntopf Jan 2004

Synthesis Of Reversible Circuits From A Subset Of Muthukrishnan-Stroud Quantum Realizable Multi-Valued Gates, Marek Perkowski, Nicholas Denler, Bruce Yen, Pawel Kerntopf

Electrical and Computer Engineering Faculty Publications and Presentations

We present a new type of quantum realizable reversible cascade. Next we present a new algorithm to synthesize arbitrary single-output ternary functions using these reversible cascades. The cascades use “Generalized Multi-Valued Gates” introduced here, which extend the concept of Generalized Ternary Gates introduced previously. While there were 216 GTGs, a total of 12 ternary gates of the new type are sufficient to realize arbitrary ternary functions. (The count can be further reduced to 5 gates, three 2-qubit and two 1-qubit). Such gates are realizable in quantum ion trap devices. For some functions, the algorithm requires fewer gates than results previously …

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A Transformation Based Algorithm For Ternary Reversible Logic Synthesis Using Universally Controlled Ternary Gates, Marek Perkowski, Eric Curtis Jan 2004

A Transformation Based Algorithm For Ternary Reversible Logic Synthesis Using Universally Controlled Ternary Gates, Marek Perkowski, Eric Curtis

Electrical and Computer Engineering Faculty Publications and Presentations

In this paper a synthesis algorithm for reversible ternary logic cascades is presented. The algorithm can find a solution for any reversible ternary function with n inputs and n outputs utilizing ternary inverter gates and the new (quantum realizable) UCTG gates which are a powerful generalization of ternary Toffoli gates and Generalized Ternary Gates [4]. The algorithm is an extension of the algorithm presented by Dueck, Maslov, and Miller in [3]. A unique feature of this algorithm is that it utilizes no extra wires to generate the outputs. A basic compaction algorithm is defined to improve the results of the …

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The Robustness Of Resource Allocation In Parallel And Distributed Computing Systems, Shoukat Ali, Howard Jay Siegel, A. A. Maciejewski Jan 2004

The Robustness Of Resource Allocation In Parallel And Distributed Computing Systems, Shoukat Ali, Howard Jay Siegel, A. A. Maciejewski

Electrical and Computer Engineering Faculty Research & Creative Works

This paper gives an overview of the material to be discussed in the invited keynote presentation by H. J. Siegel. Performing computing and communication tasks on parallel and distributed systems involves the coordinated use of different types of machines, networks, interfaces, and other resources. Decisions about how best to allocate resources are often based on estimated values of task and system parameters, due to uncertainties in the system environment. An important research problem is the development of resource management strategies that can guarantee a particular system performance given such uncertainties. We have designed a methodology for deriving the degree of …

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A Method For Enhancing The Snapshot Performance In San Volume Manager, Chang-Soo Kim, Dong-Jae Kang, Young-Ho Kim, Hag-Young Kim, Myoung-Jun Kim, Yu-Hyeon Bak Jan 2004

A Method For Enhancing The Snapshot Performance In San Volume Manager, Chang-Soo Kim, Dong-Jae Kang, Young-Ho Kim, Hag-Young Kim, Myoung-Jun Kim, Yu-Hyeon Bak

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

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A New Estimative Current Mode Control Technique For Dc-Dc Converters Operating In Discontinuous Conduction Mode, Mehdi Ferdowsi, Zhong Nie, Ali Emadi Jan 2004

A New Estimative Current Mode Control Technique For Dc-Dc Converters Operating In Discontinuous Conduction Mode, Mehdi Ferdowsi, Zhong Nie, Ali Emadi

Electrical and Computer Engineering Faculty Research & Creative Works

A new digital control technique for power converters operating in discontinuous conduction mode (DCM) is introduced and applied to a boost converter. In contrast to the conventional analogue control methods, the principal idea of this new control scheme is to use real-time analysis and estimate the required on-time of the switch based on the dynamic of the system. The proposed control algorithm can easily be programmed in a digital signal processor (DSP). This novel technique is applicable to any converter operating in DCM including power factor correctors (PFC). However, this work mainly focuses on the boost topology. In this paper, …

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Boost Integrated Push-Pull Rectifier With Power Factor Correction And Output Voltage Regulation Using A New Digital Control Technique, Zhong Nie, Mehdi Ferdowsi, Ali Emadi Jan 2004

Boost Integrated Push-Pull Rectifier With Power Factor Correction And Output Voltage Regulation Using A New Digital Control Technique, Zhong Nie, Mehdi Ferdowsi, Ali Emadi

Electrical and Computer Engineering Faculty Research & Creative Works

An integrated converter is a synthesized converter based on the overall system integration, which is simplified by the system objective and can implement the system functions similar to the discrete converters. An integrated converter consists of converter sets; each converter set has a special function defined by the designer. A family of DC/DC Boost based integrated rectifiers with two active switches can be derived by the integration concept. In this paper, Boost + Push-Pull integrated converter is introduced and derived. To regulate the output voltage and shape the input current, a new simple digital control method is applied. In contrast …

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Ergodic Capacity Of Doubly Selective Rayleigh Fading Mimo Channels, Chengshan Xiao, Y. Rosa Zheng Jan 2004

Ergodic Capacity Of Doubly Selective Rayleigh Fading Mimo Channels, Chengshan Xiao, Y. Rosa Zheng

Electrical and Computer Engineering Faculty Research & Creative Works

The ergodic capacity is investigated for doubly selective (frequency selective and time varying) MIMO Rayleigh fading channels. A closed form formula is derived that quantifies the effect of the ISI fading on the ergodic capacity into an ISI degradation factor. It is discovered that, in general frequency selective MIMO channels, the inter-tap correlations of the ISI fading will reduce the ergodic capacity comparing to the frequency flat fading channel. Only in the special case when the ISI fading does not have inter-tap correlations will the ergodic capacity be the same as that of the frequency flat channel. This new formula …

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Measuring The Robustness Of A Resource Allocation, Shoukat Ali, A. A. Maciejewski, Howard Jay Siegel, Jong-Kook Kim Jan 2004

Measuring The Robustness Of A Resource Allocation, Shoukat Ali, A. A. Maciejewski, Howard Jay Siegel, Jong-Kook Kim

Electrical and Computer Engineering Faculty Research & Creative Works

Parallel and distributed systems may operate in an environment that undergoes unpredictable changes causing certain system performance features to degrade. Such systems need robustness to guarantee limited degradation despite fluctuations in the behavior of its component parts or environment. This research investigates the robustness of an allocation of resources to tasks in parallel and distributed systems. The main contributions are 1) a mathematical description of a metric for the robustness of a resource allocation with respect to desired system performance features against multiple perturbations in multiple system and environmental conditions, and 2) a procedure for deriving a robustness metric for …

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