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2006

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Self-Optimization Of Optical Confinement In An Ultraviolet Photonic Crystal Slab Laser, Alexey Yamilov, X. Wu, X. Liu, Hui Cao, Robert P. H. Chang Jan 2006

Self-Optimization Of Optical Confinement In An Ultraviolet Photonic Crystal Slab Laser, Alexey Yamilov, X. Wu, X. Liu, Hui Cao, Robert P. H. Chang

Physics Faculty Research & Creative Works

We studied numerically and experimentally the effects of structural disorder on the performance of ultraviolet photonic crystal slab lasers. Optical gain selectively amplifies the high-quality modes of the passive system. For these modes, the in-plane and out-of-plane leakage rates may be automatically balanced in the presence of disorder. The spontaneous optimization of in-plane and out-of-plane confinement of light in a photonic crystal slab may lead to a reduction of the lasing threshold.

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Slow Dynamics At The Smeared Phase Transition Of Randomly Layered Magnets, Shellie Huether, Ryan Kinney, Thomas Vojta Jan 2006

Slow Dynamics At The Smeared Phase Transition Of Randomly Layered Magnets, Shellie Huether, Ryan Kinney, Thomas Vojta

Physics Faculty Research & Creative Works

We investigate a model for randomly layered magnets, viz., a three-dimensional Ising model with planar defects. The magnetic phase transition in this system is smeared because static long-range order can develop on isolated rare spatial regions. Here, we report large-scale kinetic Monte Carlo simulations of the dynamical behavior close to the smeared phase transition, which we characterize by the spin (time) autocorrelation function. In the paramagnetic phase, its behavior is dominated by Griffiths effects similar to those in magnets with point defects. In the tail region of the smeared transition the dynamics is even slower: the autocorrelation function decays like …

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Echo State Networks For Determining Harmonic Contributions From Nonlinear Loads, Joy Mazumdar, Ganesh K. Venayagamoorthy, Frank C. Lambert, Ronald G. Harley Jan 2006

Echo State Networks For Determining Harmonic Contributions From Nonlinear Loads, Joy Mazumdar, Ganesh K. Venayagamoorthy, Frank C. Lambert, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

This paper investigates the application of a new kind of recurrent neural network called Echo State Networks (ESNs) for the problem of measuring the actual amount of harmonic current injected into a power network by a nonlinear load. The interaction between loads connected to a point of common coupling (PCC) is a highly dynamic process. The determination of true harmonic current injection by individual loads is further complicated by the fact that the supply voltage waveform at the PCC is distorted by other loads at the PCC or further upstream and is therefore rarely a pure sinusoid. Harmonics in a …

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Effects Of Facts Devices On A Power System Which Includes A Large Wind Farm, Wei Qiao, Ganesh K. Venayagamoorthy, Ronald G. Harley Jan 2006

Effects Of Facts Devices On A Power System Which Includes A Large Wind Farm, Wei Qiao, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

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Empirical Study Of An Unconstrained Modified Particle Swarm Optimization, Ganesh K. Venayagamoorthy, Phillip W. Moore Jan 2006

Empirical Study Of An Unconstrained Modified Particle Swarm Optimization, Ganesh K. Venayagamoorthy, Phillip W. Moore

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, an unconstrained modified particle swarm optimization (UMPSO) algorithm is introduced and studied empirically. Four well known benchmark functions, with asymmetric initial position values, are used as testing functions for the UMPSO algorithm. The UMPSO is a variation of the canonical PSO in which the velocity and position is unconstrained, an additional strategic component is added, and the social component term has been modified. The strategy component is used instead of varying parameters or mutation to enhance diversity in the swarm during the search. The UMPSO algorithm is then compared to results obtained from the constrained canonical PSO …

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Forecasting Using The Mahalanobis-Taguchi System In The Presence Of Collinearity, Elizabeth A. Cudney, Kenneth M. Ragsdell Jan 2006

Forecasting Using The Mahalanobis-Taguchi System In The Presence Of Collinearity, Elizabeth A. Cudney, Kenneth M. Ragsdell

Engineering Management and Systems Engineering Faculty Research & Creative Works

The Mahalanobis Taguchi System is a diagnosis and forecasting method for multivariate data. Mahalanobis distance is a measure based on correlations between the variables and different patterns that can be identified and analyzed with respect to a base or reference group. the issue of multicollinearity is not adequately addressed in the MTS method. in cases where strong relationships exist between variables, the correlation matrix becomes almost singular, and the inverse matrix is not accurate. Multicollinearity can be handled by utilizing the adjoint matrix of the correlation matrix and Gram-Schmidt orthogonalization. This paper presents a case study of the MTS methodology …

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Intentional Islanding And Adaptive Load Shedding To Avoid Cascading Outages, Badrul H. Chowdhury, H. Manjari Dola Jan 2006

Intentional Islanding And Adaptive Load Shedding To Avoid Cascading Outages, Badrul H. Chowdhury, H. Manjari Dola

Electrical and Computer Engineering Faculty Research & Creative Works

Predetermined islanding scenarios along with automated load shedding schemes are applied once a prospective cascading outage condition is predicted. If required, additional distributed generation at specified locations in the system is also determined. The choice of different islands along with loads to be shed is then made available to the operator so as to be armed for action in case the system security is compromised. Determination of line outages that lead to disastrous consequences, intentional islanding schemes, and load shedding schemes have been explored individually. A plan integrating these defense mechanisms coupled with the possibility of using distributed generation where …

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Unifying Value Methodology And Robust Design To Achieve Design For Six Sigma, Vivek K. Jikar, Elizabeth A. Cudney, Kenneth M. Ragsdell, Chuck T. Hui Jan 2006

Unifying Value Methodology And Robust Design To Achieve Design For Six Sigma, Vivek K. Jikar, Elizabeth A. Cudney, Kenneth M. Ragsdell, Chuck T. Hui

Engineering Management and Systems Engineering Faculty Research & Creative Works

The concept of product or system function is considered as described in the Taguchi System of Quality Engineering. the importance of transfer functions is also discussed, and a review of conventional value analysis techniques is given. This paper proposes a combination of the principles of robust design and value methodology to enable on-target functionality and direct cost allocation early in the product development process. the discussion on integration of value analysis principles in robust design methodology is provided considering the six-sigma environment. Copyright © 2006 SAE International.

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Electrochemical Deposition And Characterization Of Fe₃O₄ Films Produced By The Reduction Of Fe(Iii)-Triethanolamine, Hiten M. Kothari, Elizabeth A. Kulp, Steven J. Limmer, Philippe Poizot, Eric W. Bohannan, Jay A. Switzer Jan 2006

Electrochemical Deposition And Characterization Of Fe₃O₄ Films Produced By The Reduction Of Fe(Iii)-Triethanolamine, Hiten M. Kothari, Elizabeth A. Kulp, Steven J. Limmer, Philippe Poizot, Eric W. Bohannan, Jay A. Switzer

Chemistry Faculty Research & Creative Works

In this paper, we demonstrate that films of magnetite, Fe3O4, can be deposited by the electrochemical reduction of a Fe(III)-triethanolamine complex in aqueous alkaline solution. the films were deposited with a columnar microstructure and a [100] preferred orientation on stainless steel substrates. In-plane electrical transport and magnetoresistance measurements were performed on the films after they were stripped off onto glass substrates. the resistance of the films was dependent on the oxygen partial pressure. We attribute the increase in resistance in O2 and the decrease in resistance in Ar to the oxidation and reduction of grain …

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A Comparative Study Of The Properties Of Polar And Nonpolar Solvent/Solute/Polystyrene Solutions In Microwave Fields Via Molecular Dynamics, Mark J. Purdue, Macduff O. Okuom, Frank D. Blum, James M. D. Macelroy, D. F. O'Shea Jan 2006

A Comparative Study Of The Properties Of Polar And Nonpolar Solvent/Solute/Polystyrene Solutions In Microwave Fields Via Molecular Dynamics, Mark J. Purdue, Macduff O. Okuom, Frank D. Blum, James M. D. Macelroy, D. F. O'Shea

Chemistry Faculty Research & Creative Works

The influence of an applied microwave field on the dynamics of methylamine-dichloromethane (DCM) mixtures bound within atactic polystyrene (a-PS) over a range of polymer densities from 30 to 94 wt % polymer was examined using atomistic molecular dynamics simulations. This study is an extension of previous studies on methylamine transport in relatively polar polystyrene solutions of methanol and dimethylformamide [M. J. Purdue et al., J. Chem. Phys. 124, 204904 (2006)]. A direct comparison is made across the three types of polystyrene solutions. Consideration is given to both solvent and reagent transport within the polymer solutions under zero-field conditions and in …

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Acid-Catalyzed Time-Efficient Synthesis Of Resorcinol-Formaldehyde Aerogels And Crosslinking With Isocyanates, Sudhir Mulik, Chariklia Sotiriou-Leventis, Nicholas Leventis Jan 2006

Acid-Catalyzed Time-Efficient Synthesis Of Resorcinol-Formaldehyde Aerogels And Crosslinking With Isocyanates, Sudhir Mulik, Chariklia Sotiriou-Leventis, Nicholas Leventis

Chemistry Faculty Research & Creative Works

Aerogels are open-cell foams derived from supercritical fluid (SCF) drying of wet gels. Their large internal void space is responsible for low thermal conductivity, high surface area and high acoustic impedance. Most aerogels are based on inorganic metal or semimetal oxide frameworks. Pekala and co-workers synthesized resorcinol-formaldehyde (RF) organic aerogels by poly-condensation of resorcinol with formaldehyde in the presence of Na2CO3 as base catalyst, followed by drying with SCF CO2. Low-density RF aerogels prepared by this method exhibit high porosities (>80%), high surface areas (400-900 m2g-1), ultrafine cell-size (<500 > Å) …

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Molecular Mass And Dynamics Of Poly(Methyl Acrylate) In The Glass Transition Region, Burak Metin, Frank D. Blum Jan 2006

Molecular Mass And Dynamics Of Poly(Methyl Acrylate) In The Glass Transition Region, Burak Metin, Frank D. Blum

Chemistry Faculty Research & Creative Works

The segmental dynamics of bulk poly(methyl acrylate) (PMA) were studied as a function of molecular mass in the glass-transition region using 2H NMR and modulated differential scanning calorimetry (MDSC). Quadrupole-echo 2H NMR spectra were obtained for four samples of methyl-deuterated PMA-d3 with different molecular masses. The resulting spectra were fit using superpositions of simulated spectra generated from the MXQET simulation program, based on a model incorporating nearest-neighbor jumps from positions on the vertices of a truncated icosahedron (soccer-ball shape). The lower molecular-mass samples, influenced by the presence of more chain ends, showed more heterogeneity (broader distribution) and lower glass transitions …

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Segmental Dynamics Of Poly(Isopropyl Acrylate)-D7 On Silica, Piyawan Krisanangkura, Frank D. Blum Jan 2006

Segmental Dynamics Of Poly(Isopropyl Acrylate)-D7 On Silica, Piyawan Krisanangkura, Frank D. Blum

Chemistry Faculty Research & Creative Works

For a polymer film deposited on a surface, the strength of the surfacesegment interaction affects the mobility of polymer-chain segments. The selfconsistent field lattice model of Scheutjens and Fleer,1 based on mean-field lattice models of polymer at interfaces,2 has been used to describe the distribution of conformations of polymers on surfaces. Adsorbed-polymer segments may be classified as belonging to loops, trains or tails. There are different techniques used to study the molecular motion of the polymer including modulated differential scanning calorimetry (MDSC)3 and nuclear magnetic resonance (NMR).4,5 in this work, solid-state deuterium (2H) NMR was used to characterize the polymer …

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Segmental Mobility Of Chain Ends In Poly(Methyl Acrylate)-D3, Burak Metin, Frank D. Blum Jan 2006

Segmental Mobility Of Chain Ends In Poly(Methyl Acrylate)-D3, Burak Metin, Frank D. Blum

Chemistry Faculty Research & Creative Works

Better control of polymeric materials can be achieved with a thorough understanding of the dynamics of their constituents. In the present study, we consider polymer chains as composed of chain middles and chain ends. Even though chain ends do not comprise much of the sample by mass, they may play a crucial role in the ultimate properties of the polymers. Although chain ends have been assigned a higher mobility, as compared to chain middles, there have not been a large number of experimental studies that directly probe their mobility. Among those, the studies of Kitahara et al.1 and Miwa et …

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Separation And Quantification Of N-Acetylcysteine-Amide (Naca) By Hplc With Fluorescence Detection, Wei Wu, Glenn Goldstein, Craig D. Adams, Richard H. Matthews, Nuran Ercal Jan 2006

Separation And Quantification Of N-Acetylcysteine-Amide (Naca) By Hplc With Fluorescence Detection, Wei Wu, Glenn Goldstein, Craig D. Adams, Richard H. Matthews, Nuran Ercal

Chemistry Faculty Research & Creative Works

N-acetyl-l-cysteine (NAC) is a well-known antioxidant that is capable of facilitating glutathione (GSH) biosynthesis and replenishing intracellular GSH under oxidatively challenging circumstances. N-acetyl-cysteine-amide (NACA), the amide form of NAC, is a newly designed and synthesized thiol-containing compound which is believed to be more lipophilic and permeable through cell membranes than NAC. The metabolic and antioxidant effects of these compounds in vitro and in vivo are under investigation. However, an analytical method that can separate and quantify both compounds simultaneously is not yet available, to the best of our knowledge. Because of their structural similarities, the two compounds are difficult to …

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Synthesis And Thermal Behavior Of Poly(Methyl Acrylate) Attached To Silica By Surface-Initiated Atrp, Manikantan B. Nair, Frank D. Blum Jan 2006

Synthesis And Thermal Behavior Of Poly(Methyl Acrylate) Attached To Silica By Surface-Initiated Atrp, Manikantan B. Nair, Frank D. Blum

Chemistry Faculty Research & Creative Works

The modification of the surface of an object dictates the response of the object to an external environment.1 Surface-modified materials and nanoparticles have attracted immense interest due to the various desirable electronic, optical and magnetic properties they possess.2 Silica is widely used as an inorganic filler. Surface modification of the silica, with a variety of organic moieties, facilitates the utilization of silica in conjunction with organic systems. The resulting organic/inorganic hybrid materials have significant potential applications. This work reports the synthesis and characterization of modified silica, and poly(methyl acrylate) attached to the modified silica. An observation of the thermal behavior …

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Conformal Internal Coating Of Macroporous Co-Continuous Mcf-Silicas With Isocyanate Derived Polymers, Nicholas Leventis, Chariklia Sotiriou-Leventis, Xiaojiang Wang, Sudhir Mulik Jan 2006

Conformal Internal Coating Of Macroporous Co-Continuous Mcf-Silicas With Isocyanate Derived Polymers, Nicholas Leventis, Chariklia Sotiriou-Leventis, Xiaojiang Wang, Sudhir Mulik

Chemistry Faculty Research & Creative Works

Since their discovery in 1992,1,2 templating sol-gel silica with structuredirecting agents has resulted in new materials with ordered mesoporous (2-50 nm) structure that is investigated for application in areas as diverse as high surface area supports for caralysts or as nanostructured drug storage and release platforms.3 Structure-directing agents are typically surfactants ranging from cationic detergents such as alkyl-trimethylammonium salts with C8-C18 hydrocarbon chains to non-ionic tertiary amines, polyethylene oxide or amphiphilic triblock copolymers such as poly(ethyleneoxide)-blockpoly( propyleneoxide)-block-poly(ethyleneoxide) (e.g., Pluronic P123). Depending on the surfactant and the conditions (e.g., kind and concentration of catalyst) the structure of the mesopores may vary …

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Effect Of Processing Conditions On Chemical Makeup Of Di-Isocyanate Crosslinked Silica Aerogels, Mary Ann B. Meador, Nicholas Leventis, Lynn A. Capadona, Plousia Vassilaras Jan 2006

Effect Of Processing Conditions On Chemical Makeup Of Di-Isocyanate Crosslinked Silica Aerogels, Mary Ann B. Meador, Nicholas Leventis, Lynn A. Capadona, Plousia Vassilaras

Chemistry Faculty Research & Creative Works

Sol-gel derived silica aerogels are attractive candidates for many unique thermal, optical, catalytic, and chemical applications1 because of their low density and high mesoporosity. However, their inherent fragility has restricted their use to, for example, insulation in extreme temperature environments such as Mars. We have previously reported crosslinking the mesoporous silica structure of an aerogel with di-isocyanates reacted with silanols on the surface,2,3 or epoxies reacting with an amine decorated silica surface.4 Either approach has been shown to significantly increase the strength of the aerogel with only a small effect on density or porosity. Thus, these hybrid materials may be …

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Neural Network-Based Output Feedback Controller For Lean Operation Of Spark Ignition Engines, Brian C. Kaul, Jagannathan Sarangapani, J. A. Drallmeier, Jonathan B. Vance, Pingan He Jan 2006

Neural Network-Based Output Feedback Controller For Lean Operation Of Spark Ignition Engines, Brian C. Kaul, Jagannathan Sarangapani, J. A. Drallmeier, Jonathan B. Vance, Pingan He

Electrical and Computer Engineering Faculty Research & Creative Works

Spark ignition (SI) engines running at very lean conditions demonstrate significant nonlinear behavior by exhibiting cycle-to-cycle dispersion of heat release even though such operation can significantly reduce NOx emissions and improve fuel efficiency by as much as 5-10%. A suite of neural network (NN) controller without and with reinforcement learning employing output feedback has shown ability to reduce the nonlinear cyclic dispersion observed under lean operating conditions. The neural network controllers consists of three NN: a) A NN observer to estimate the states of the engine such as total fuel and air; b) a second NN for generating virtual input; …

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Neuro Control Of Nonlinear Discrete Time Systems With Deadzone And Input Constraints, Pingan He, Wenzhi Gao, Jagannathan Sarangapani Jan 2006

Neuro Control Of Nonlinear Discrete Time Systems With Deadzone And Input Constraints, Pingan He, Wenzhi Gao, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

A neural network (NN) controller in discrete time is designed to deliver a desired tracking performance for a class of uncertain nonlinear systems with unknown deadzones and magnitude constraints on the input. The NN controller consists of two NNs: the first NN for compensating the unknown deadzones; and the second NN for compensating the uncertain nonlinear system dynamics. The magnitude constraints on the input are modeled as saturation nonlinearities and they are dealt with in the Lyapunov-based controller design. The uniformly ultimate boundedness (UUB) of the closed-loop tracking errors and the neural network weights estimation errors is demonstrated via Lyapunov …

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Segmental Dynamics In Poly(Methyl Acrylate) On Silica: Molecular-Mass Effects, Burak Metin, Frank D. Blum Jan 2006

Segmental Dynamics In Poly(Methyl Acrylate) On Silica: Molecular-Mass Effects, Burak Metin, Frank D. Blum

Chemistry Faculty Research & Creative Works

The effect of molecular mass on the segmental dynamics of poly(methyl acrylate) (PMA) adsorbed on silica was studied using deuterium quadrupole-echo nuclear magnetic resonance (NMR) and modulated differential scanning calorimetry. Samples adsorbed on silica (all about 1.5 mg PMA/m2 silica) were shown to have more restricted segmental mobility, and higher Tg's, than the corresponding bulk PMA samples. Around the glass-transition region, adsorbed samples exhibited segmental mobility, which could be classified as heterogeneous due to a superposition of more-mobile and less-mobile components present in the deuterium NMR spectra. This heterogeneity was consistent with a motional gradient with more-mobile segments near the …

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Segmental Dynamics Of Poly(Vinyl Acetate)- D₃ Absorbed On Silica By Solid State 2hnmr: Effect Of Small Molecule Plasticizer, Rakesh R. Nambiar, Frank D. Blum Jan 2006

Segmental Dynamics Of Poly(Vinyl Acetate)- D₃ Absorbed On Silica By Solid State 2hnmr: Effect Of Small Molecule Plasticizer, Rakesh R. Nambiar, Frank D. Blum

Chemistry Faculty Research & Creative Works

There has been significant progress in understanding the behavior of polymeric thin films on surfaces. The change in the apparent glass transition temperature (Tg) of supported thin polymer films with thickness (Tg -nanoconfinement effect) has been widely studied over the last fifteen years. While many studies focused on the thickness dependence of Tg, there are other aspects which are important to understand in a nanoconfined polymer system. For example, polymeric photoresists contain small-molecule photoactive compounds, plasticizers, and processing aids. These components interact with the polymer chains and affect the segmental mobility, which, in turn, affects the Tg - nanoconfinement effect. …

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Novel Sum-Of-Sinusoids Simulation Models For Rayleigh And Rician Fading Channels, Chengshan Xiao, Y. Rosa Zheng, N. C. Beaulieu Jan 2006

Novel Sum-Of-Sinusoids Simulation Models For Rayleigh And Rician Fading Channels, Chengshan Xiao, Y. Rosa Zheng, N. C. Beaulieu

Electrical and Computer Engineering Faculty Research & Creative Works

The statistical properties of Clarke's fading model with a finite number of sinusoids are analyzed, and an improved reference model is proposed for the simulation of Rayleigh fading channels. A novel statistical simulation model for Rician fading channels is examined. The new Rician fading simulation model employs a zero-mean stochastic sinusoid as the specular (line-of-sight) component, in contrast to existing Rician fading simulators that utilize a non-zero deterministic specular component. The statistical properties of the proposed Rician fading simulation model are analyzed in detail. It is shown that the probability density function of the Rician fading phase is not only …

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On Discrete-Time Modeling Of Time-Varying Wssus Fading Channels, Christian Sgraja, Chengshan Xiao Jan 2006

On Discrete-Time Modeling Of Time-Varying Wssus Fading Channels, Christian Sgraja, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we consider the serial concatenation of linear time-varying (LTV) systems and its impact on the discrete-time modeling of wide-sense stationary uncorrelated scattering (WSSUS) fading channels. By deriving an expression for the composite impulse response of the overall concatenated system, we find that unlike the time-invariant case, the concatenation of LTV systems is not commutative, i. e., the order of arrangement affects the overall impulse response. This has significant impact when a digital transmission over a time-varying fading channel, which is an LTV channel, is represented by an equivalent discrete-time model that incorporates both transmitter and receiver filters. …

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Operational Characteristics Of Wind Plants And Windfarms, Badrul H. Chowdhury Jan 2006

Operational Characteristics Of Wind Plants And Windfarms, Badrul H. Chowdhury

Electrical and Computer Engineering Faculty Research & Creative Works

A wide range of power generation technologies exist today, whose characteristics can vary significantly. Additionally, a diverse range of wind turbines are available in the market. With experienced wind developers taking the charge in installing multi-megawatt-size windfarms at a rapid pace, the role of wind power in electricity generation is bound to grow in significance in the coming years. This panel takes a critical look at the operating characteristics of existing and planned wind power generation systems and their relationship to interconnection requirements and performance standards.

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Power System Control With An Embedded Neural Network In Hybrid System Modeling, Seung-Mook Baek, Jung-Wook Park, Ganesh K. Venayagamoorthy Jan 2006

Power System Control With An Embedded Neural Network In Hybrid System Modeling, Seung-Mook Baek, Jung-Wook Park, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

The output limits of the power system stabilizer (PSS) can improve the system damping performance immediately following a large disturbance. Due to non-smooth nonlinearities from the saturation limits, these values cannot be determined by the conventional tuning methods based on linear analysis. Only ad hoc tuning procedures can been used. A feedforward neural network (FFNN) (with a structure of multilayer perceptron neural network) is applied to identify the dynamics of an objective function formed by the states, and thereafter to compute the gradients required in the nonlinear parameter optimization. Moreover, its derivative information is used to replace that obtained from …

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Decentralized Power Control With Implementation For Rfid Networks, Kainan Cha, Anil Ramachandran, David Pommerenke, Jagannathan Sarangapani Jan 2006

Decentralized Power Control With Implementation For Rfid Networks, Kainan Cha, Anil Ramachandran, David Pommerenke, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

In radio frequency identification (RFID) systems, the detection range and read rates will suffer from interference among high power reading devices. This problem grows severely and degrades system performance in dense RFID networks. In this paper, we investigate a suite of feasible power control schemes to ensure overall coverage area of the system while maintaining a desired read rate. The power control scheme and MAC protocol dynamically adjusts the RFID reader power output in response to the interference level seen locally during tag reading for an acceptable signal-to-noise ratio (SNR). We present novel distributed adaptive power control (DAPC) and probabilistic …

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Design And Implementation Of A Storage Management Method For Content Distribution, Chang-Soo Kim, Yu-Hyeon Bak, Sang-Min Woo, Won-Jae Lee, Nunm-Ok Gee, Hag-Young Kim Jan 2006

Design And Implementation Of A Storage Management Method For Content Distribution, Chang-Soo Kim, Yu-Hyeon Bak, Sang-Min Woo, Won-Jae Lee, Nunm-Ok Gee, Hag-Young Kim

Electrical and Computer Engineering Faculty Research & Creative Works

The SMART system is a special purpose server developed by ETRI and designed for efficient streaming services over high speed networks. The SMART server has one or more special purpose NS (Network-Storage) card. The NS card has several disks that store multimedia contents. However all of the multimedia contents to be serviced cannot be stored at the server. In this paper, we will describe the storage management mechanism in design and implementation aspects. With this storage management mechanism, the SMART server can provide effectiveness in managing storage and distributing some contents from a source station to streaming service servers.

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Dynamic Simulation Of A Mems Cantilever Switch, James W. Fonda, Steve Eugene Watkins Jan 2006

Dynamic Simulation Of A Mems Cantilever Switch, James W. Fonda, Steve Eugene Watkins

Electrical and Computer Engineering Faculty Research & Creative Works

The dynamic behavior of a micro-electro-mechanicalsystem (MEMS) cantilever switch is investigated. Overactuation of the switch can degrade bounce characteristics and reduce the lifetime of the contacts. This work concerns the development of a control system that limits the number of switch bounces and reduces the impact force on the beam tip. A limited mass-spring analysis of the tip-position is given and an associated control approach is applied. Input limiting, state-feedback, and adaptive control methods are compared. All results demonstrate improved switch bounce characteristics for the simplified beam model with the adaptive showing the best performance improvement. A comprehensive finite element …

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Fault-Tolerant Control For Sssc Using Neural Networks And Pso, Wei Qiao, Ganesh K. Venayagamoorthy, Ronald G. Harley Jan 2006

Fault-Tolerant Control For Sssc Using Neural Networks And Pso, Wei Qiao, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

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