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2007

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Articles 18031 - 18060 of 18446

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Leadership In Knowledge Sharing: Creating Value Through Collaboration, Thomas Menkhoff, Yue Wah Chay, Hans-Dieter Evers, Benjamin Loh Jan 2007

Leadership In Knowledge Sharing: Creating Value Through Collaboration, Thomas Menkhoff, Yue Wah Chay, Hans-Dieter Evers, Benjamin Loh

Research Collection Lee Kong Chian School Of Business

This study aims to understand the antecedents of knowledge sharing behavior amongst tenant firms in Science and Technology Parks (STPs) which has been highlighted as a key factor for the development of an epistemic culture of innovation in STPs. Components of a model of knowledge management leadership with a focus on knowledge sharing and innovative value creation in STPs are developed inspired by the work of Nonaka, Nahapiet and Ghoshal, Guns and others. Collection of data on various relevant measures is ongoing, covering technology firms and STPs in Singapore and other Asian countries. Besides outlining model components and hypotheses, tentative …

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Frequency-Domain Measurement Method For The Analysis Of Esd Generators And Coupling, Jayong Koo, Qing Cai, Giorgi Muchaidze, Andrew Martwick, Kai Wang, David Pommerenke Jan 2007

Frequency-Domain Measurement Method For The Analysis Of Esd Generators And Coupling, Jayong Koo, Qing Cai, Giorgi Muchaidze, Andrew Martwick, Kai Wang, David Pommerenke

Electrical and Computer Engineering Faculty Research & Creative Works

A method for analyzing electrostatic discharge (ESD) generators and coupling to equipment under test in the frequency domain is proposed. In ESD generators, the pulses are excited by the voltage collapse across relay contacts. The voltage collapse is replaced by one port of a vector network analyer (VNA). All the discrete and structural elements that form the ESD current pulse and the transient fields are excited by the VNA as if they were excited by the voltage collapse. In such a way, the method allows analyzing the current and field-driven linear coupling without having to discharge an ESD generator, eliminating …

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Comparison Of Nonuniform Optimal Quantizer Designs For Speech Coding With Adaptive Critics And Particle Swarm, Ganesh K. Venayagamoorthy, Wenwei Zha Jan 2007

Comparison Of Nonuniform Optimal Quantizer Designs For Speech Coding With Adaptive Critics And Particle Swarm, Ganesh K. Venayagamoorthy, Wenwei Zha

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents the design of a companding nonuniform optimal scalar quantizer for speech coding. The quantizer is designed using two neural networks to perform the nonlinear transformation. These neural networks are used in the front and back ends of a uniform quantizer. Two approaches are presented in this paper namely adaptive critic designs and particle swarm optimization, aiming to maximize the signal-to-noise ratio. The comparison of these optimal quantizer designs over a bit-rate range of 3-6 is presented. The perceptual quality of the coding is evaluated by the International Telecommunication Union's Perceptual Evaluation of Speech Quality standard

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Mode Suppressed Tem Cell Design For High Frequency Ic Measurements, Shaowei Deng, David Pommerenke, Todd H. Hubing, James L. Drewniak, Daryl G. Beetner, Dongshik Shin, Sungnam Kim, Hocheol Kwak Jan 2007

Mode Suppressed Tem Cell Design For High Frequency Ic Measurements, Shaowei Deng, David Pommerenke, Todd H. Hubing, James L. Drewniak, Daryl G. Beetner, Dongshik Shin, Sungnam Kim, Hocheol Kwak

Electrical and Computer Engineering Faculty Research & Creative Works

TEM cells or GTEM cells can be used to evaluate the radiated emissions of integrated circuits (ICs). The applicable frequency bandwidth of a TEM cell is limited due to the resonances of higher order modes. This paper describes how a TEM cell can be modified to extend the frequency range without changing the test topology. Several methods are proposed and implemented to suppress the higher order modes. The magnetic field coupling and electric field coupling are evaluated for the new design. The frequency bandwidth of the modified TEM cell is extended from original 1 GHz to 2.5 GHz.

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Multiclass Cancer Classification Using Semisupervised Ellipsoid Artmap And Particle Swarm Optimization With Gene Expression Data, Georgios C. Anagnostopoulos, Donald C. Wunsch, Rui Xu Jan 2007

Multiclass Cancer Classification Using Semisupervised Ellipsoid Artmap And Particle Swarm Optimization With Gene Expression Data, Georgios C. Anagnostopoulos, Donald C. Wunsch, Rui Xu

Electrical and Computer Engineering Faculty Research & Creative Works

It is crucial for cancer diagnosis and treatment to accurately identify the site of origin of a tumor. with the emergence and rapid advancement of DNA microarray technologies, constructing gene expression profiles for different cancer types has already become a promising means for cancer classification. In addition to research on binary classification such as normal versus tumor samples, which attracts numerous efforts from a variety of disciplines, the discrimination of multiple tumor types is also important. Meanwhile, the selection of genes which are relevant to a certain cancer type not only improves the performance of the classifiers, but also provides …

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Wave Propagation On Power Cables With Special Regard To Metallic Screen Design, R. Papazyan, Per Pettersson, David Pommerenke Jan 2007

Wave Propagation On Power Cables With Special Regard To Metallic Screen Design, R. Papazyan, Per Pettersson, David Pommerenke

Electrical and Computer Engineering Faculty Research & Creative Works

The high frequency properties of coaxial power cables are modeled using time- and frequency-domain numerical simulations. This is required due to the complex helical structure of the outer metallic screen. The finite element (FEM) and finite difference time domain methods (FDTD) have been employed to study the effect of screen spiralization. It is established that this screen design causes a dependence of the cable high frequency characteristics on the surrounding medium. Analytical model based on modal analysis of wave propagation in coaxial cables confirms the numerical observations.

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Obiora Chinedu Okafor, Legitimizing Human Right Ngos: Lessons From Nigeria, Joel M. Ngugi Jan 2007

Obiora Chinedu Okafor, Legitimizing Human Right Ngos: Lessons From Nigeria, Joel M. Ngugi

Fordham International Law Journal

Professor Obiora Chinedu Okafor of Osgoode Hall School of Law, Toronto, Canada, has written a well-researched and valuable book about Human Rights Non-Governmental Organizations ("NGOs") in Nigeria. ... " Similarly, in many countries, NGOs, in their capacity as civic society, have been given official roles in some key governance institutions such as in Nigerian National Human Rights Commissions, media watchdogs, Governmental Commissions, and so forth. In chapter five of the book, Professor Okafor candidly describes the funding patterns of human rights NGOs in Nigeria. As Professor Okafor tells the story, the trail of the "popular legitimization crisis" of local human …

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U.S. - China Relations And Darfur, Chin-Hao Huang Jan 2007

U.S. - China Relations And Darfur, Chin-Hao Huang

Fordham International Law Journal

This Essay will begin by first assessing China's economic stakes in Sudan. While economic interests and priorities remain important, it does not sufficiently explain China's shifting position on Darfur. The Essay will then examine the critical factors shaping China's expanding role in Africa, more broadly, as an important context in understanding its evolving approach to Sudan and the Darfur crisis. It will then delve more deeply into Beijing's accommodating shifts on Darfur, illustrating and mapping out the subtleties exhibited in China's diplomatic and economic engagements with the United States on the Darfur question.

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Environmental Spill-Overs Into General Community Law, Professor Dr. Jan H. Jans, Professor Dr. Hanna G. Sevenster, Jos M.P. Janssen Jan 2007

Environmental Spill-Overs Into General Community Law, Professor Dr. Jan H. Jans, Professor Dr. Hanna G. Sevenster, Jos M.P. Janssen

Fordham International Law Journal

This Article will illustrate that indeed, European environmental law is not just another sectoral policy area of the European Union (“EU”). Over the years it has proven to have a major impact on various general doctrines of European law. In that sense, European environmental law had (and still has) an important spill-over impact upon general European Community (“EC”) law. It is the modest ambit of this Article to illustrate some of the environmental spill-overs into general European law, specifically examining the role of the European Court of Justice (“ECJ”) and its case law.

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The Legal Representation Of The Singaporean Home And The Influence Of The Common Law, Hang Wu Tang Jan 2007

The Legal Representation Of The Singaporean Home And The Influence Of The Common Law, Hang Wu Tang

Research Collection Yong Pung How School Of Law

The purpose of this article is to examine the principal laws that have a significant impact in shaping the meaning of the home in Singapore. This article makes two contributions to the pre-existing literature. First, the significant case law and statutes in Singapore affecting the concept of the home are collated and discussed. Second, in discussing these laws as a coherent whole, this article attempts to draw together the meaning of the home in the Singaporean context. The relevant laws are examined to determine whether the Western conception of “the home as a person's castle” is present in Singaporean law. …

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Pilot Program To Assess Seismic Hazards Of The Granite City, Monks Mound, And Columbia Bottom Quadrangles, St. Louis Metropolitan Area, Missouri And Illinois, Deniz Karadeniz Jan 2007

Pilot Program To Assess Seismic Hazards Of The Granite City, Monks Mound, And Columbia Bottom Quadrangles, St. Louis Metropolitan Area, Missouri And Illinois, Deniz Karadeniz

Doctoral Dissertations

"Three 1:24000 scale quadrangles were selected for a pilot program intended to evaluate seismic site response across the spectrum of geologic conditions underlying the St. Louis Metropolitan area, using the Granite City, Monks Mound and Columbia Bottom quadrangles. These evaluations included assessments of: i) site amplification distributions; ii) probabilistic hazard analysis of PGA, 0.2 second and 1.0 second spectral accelerations for 2%, 5% and 10% probability of exceedance in 50 years; iii) two scenario earthquakes and their associated PGA, 0.2 sec, and 1 sec spectral accelerations; and v) sensitivity and uncertainty analyses. These hazard maps were prepared using a fully-probabilistic …

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An Indirect Loss Estimation Methodology To Account For Regional Earthquake Damage To Highway Bridges, Chakkaphan Tirasirichai Jan 2007

An Indirect Loss Estimation Methodology To Account For Regional Earthquake Damage To Highway Bridges, Chakkaphan Tirasirichai

Doctoral Dissertations

"This study proposes an integrated framework to estimate the indirect economic loss due to damaged bridges within the highway system from an earthquake event. The framework is designed to be general and convenient to apply to other study regions. In this dissertation, a simulated earthquake scenario centered in St. Louis Missouri with a magnitude 7.0 was used as a case study. The research results have clearly shown that the indirect losses are significant when compared to the direct loss. Policymakers can apply this study framework and the results as a guide and decision tool for developing an appropriate preventive action …

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Quality Loss Function - Common Methodology For Nominal-The-Best, Smaller-The-Better, And Larger-The-Better Cases, Naresh Kumar Sharma, Kenneth M. Ragsdell Jan 2007

Quality Loss Function - Common Methodology For Nominal-The-Best, Smaller-The-Better, And Larger-The-Better Cases, Naresh Kumar Sharma, Kenneth M. Ragsdell

Engineering Management and Systems Engineering Faculty Research & Creative Works

The quality loss function developed by Dr. Genichi Taguchi considers three cases including nominal-the-best, smaller-the-better, and larger-the-better. the methodology used to deal with the larger-the-better case is slightly different from that for the smaller-the-better and nominal-the-better cases. This paper attempts to bring about similarity among the three cases by introducing a term called the "target-mean ratio" and proposing a common formula for all three cases. the "target-mean ratio" can take different values to represent all three cases to bring about consistency and simplify the model. Also, it eliminates the assumption of target performance at infinite level and brings the model …

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Faculty Senate Minutes 2006 - 2007, Missouri University Of Science And Technology Faculty Senate Jan 2007

Faculty Senate Minutes 2006 - 2007, Missouri University Of Science And Technology Faculty Senate

Minutes & Agendas

No abstract provided.

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Steel Deck Institute Design Manual For Composite Decks, Form Decks, And Roof Decks, Steel Deck Institute Jan 2007

Steel Deck Institute Design Manual For Composite Decks, Form Decks, And Roof Decks, Steel Deck Institute

Steel Deck Institute (SDI) Specifications and Manuals (1939 - present)

No abstract provided.

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Análisis De Deslizamientos En La Ciudad Capital Utilizando Sistemas De Información Geográfica, Pedro Pablo Conlledo, Ronaldo Luna Jan 2007

Análisis De Deslizamientos En La Ciudad Capital Utilizando Sistemas De Información Geográfica, Pedro Pablo Conlledo, Ronaldo Luna

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

En Guatemala, los daños ocasionados por deslizamientos de tierra son innumerables, y sin embargos son pocos los esfuezos que se han hecho a nivel nacional por estudiarlos. El principal objetivo de este trabajo fue utilizar Sistemas de lnformacion Geografica (SlG) para estudiar sistematicamente la ocurrencia de deslizamientos en el Departamento de Guatemala con la informacion disponible.

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Visual Traffic Movement Counts At Intersection For Origin-Destination (O-D) Trip Table Estimation, S. Lee, Hojong Baik, J. Park Jan 2007

Visual Traffic Movement Counts At Intersection For Origin-Destination (O-D) Trip Table Estimation, S. Lee, Hojong Baik, J. Park

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Origin-destination (O-D) trip table is necessary information for transportation planning and traffic impact study. However, current O-D estimations rely on estimated directional traffic counts at intersections, which obviously diminish reliability in the table. A video-based vehicle tracking system that utilizes wide view-angle lenses has been studied [26] to provide accurate direction traffic counts. The system expands the area covered by a single camera and uses a particle filtering method to handle environmental changes as well as geometric distortion caused by those lenses. This paper shows tracking capability of the system and also shows how to incorporate the directional traffic counts …

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Hydro-Nexrad Radar-Rainfall Estimation Algorithm Development, Testing And Evaluation, Witold F. Krajewski, Bong Chul Seo, Anton Kruger, Piotr Domaszczynski, Gabriele Villarini, Charles Gunyon Jan 2007

Hydro-Nexrad Radar-Rainfall Estimation Algorithm Development, Testing And Evaluation, Witold F. Krajewski, Bong Chul Seo, Anton Kruger, Piotr Domaszczynski, Gabriele Villarini, Charles Gunyon

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The Hydro-NEXRAD radar-rainfall estimation algorithms involve three main components: 1) preprocessing, 2) rain rate, and 3) rainfall accumulation. The preprocessing algorithm performs the quality control of reflectivity volume data and generates a hybrid scan. That is, reflectivity values for each azimuth and range bin are assigned from the several lowest elevation angles. It optionally estimates an azimuth-dependent vertical reflectivity profile and performs a correction for range effects. The rain rate algorithm converts the corrected reflectivity to rainfall intensity. The user can specify any power-law type empirical relationship between reflectivity and rainfall intensity. The last step of rainfall estimation is to …

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Implementation Of A Converter In Sequence Domain To Counter Voltage Imbalances, Murali M. Baggu, Badrul H. Chowdhury Jan 2007

Implementation Of A Converter In Sequence Domain To Counter Voltage Imbalances, Murali M. Baggu, Badrul H. Chowdhury

Electrical and Computer Engineering Faculty Research & Creative Works

This paper demonstrates the basic problem of the conventional d-axis and q-axis control applied to a voltage source converter (VSC) during a system imbalance. The specific imbalances studied are a balanced fault and an unbalanced fault at the terminals of the converter. The dc link voltage of the VSC is disturbed during the unbalanced fault due to negative sequence components in the system. The sequence characteristics of the system during an imbalance are further analyzed. A novel controller in the sequence domain is proposed. The positive sequence components of the control are implemented in the positive synchronous reference frame and …

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Neural Network Controller Development And Implementation For Spark Ignition Engines With High Egr Levels, Jonathan B. Vance, Atmika Singh, Brian C. Kaul, Jagannathan Sarangapani, J. A. Drallmeier Jan 2007

Neural Network Controller Development And Implementation For Spark Ignition Engines With High Egr Levels, Jonathan B. Vance, Atmika Singh, Brian C. Kaul, Jagannathan Sarangapani, J. A. Drallmeier

Electrical and Computer Engineering Faculty Research & Creative Works

Past research has shown substantial reductions in the oxides of nitrogen (NOx) concentrations by using 10% -25% exhaust gas recirculation (EGR) in spark ignition (SI) engines (see Dudek and Sain, 1989). However, under high EGR levels, the engine exhibits strong cyclic dispersion in heat release which may lead to instability and unsatisfactory performance preventing commercial engines to operate with high EGR levels. A neural network (NN)-based output feedback controller is developed to reduce cyclic variation in the heat release under high levels of EGR even when the engine dynamics are unknown by using fuel as the control input. A separate …

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Process Development For The Formation Of Post-Bonding Biorecognition Layers In Microfluidic Biosensors, Martin G. Perez, Phaninder R. Kanikella, James N. Reck, Chang-Soo Kim, Matthew O'Keefe Jan 2007

Process Development For The Formation Of Post-Bonding Biorecognition Layers In Microfluidic Biosensors, Martin G. Perez, Phaninder R. Kanikella, James N. Reck, Chang-Soo Kim, Matthew O'Keefe

Electrical and Computer Engineering Faculty Research & Creative Works

Formation of the biorecognition layers within microfluidic sensor channels must be done after the completion of the channel structure since these layers cannot withstand the wafer bonding temperature. We propose a new post-bonding immobilization process to prepare the enzyme layers within microfluidic channels of electrochemical biosensors. An array of Pt vertical electrodes is electroplated using a SU-8 mold. The cured SU-8 is then removed by plasma etching to expose the Pt electrode and to define the fluidic channel cavity simultaneously. An array of enzyme posts is formed on the Pt surface by either electropolymerizing or photopolymerizing enzyme precursor solutions injected …

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Route Aware Predictive Congestion Control Protocol For Wireless Sensor Networks, Carl Larsen, Maciej Jan Zawodniok, Jagannathan Sarangapani Jan 2007

Route Aware Predictive Congestion Control Protocol For Wireless Sensor Networks, Carl Larsen, Maciej Jan Zawodniok, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

Congestion in wireless sensor networks (WSN) may lead to packet losses or delayed delivery of important information rendering the WSN-based monitoring or control system useless. In this paper a routing-aware predictive congestion control (RPCC) yet decentralized scheme for WSN is presented that uses a combination of a hop by hop congestion control mechanism to maintain desired level of buffer occupancy, and a dynamic routing scheme that works in concert with the congestion control mechanism to forward the packets through less congested nodes. The proposed adaptive approach restricts the incoming traffic thus preventing buffer overflow while maintaining the rate through an …

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Two Neural Network Based Decentralized Controller Designs For Large Scale Power Systems, Wenxin Liu, Jagannathan Sarangapani, Ganesh K. Venayagamoorthy, Donald C. Wunsch, Mariesa Crow, David A. Cartes Jan 2007

Two Neural Network Based Decentralized Controller Designs For Large Scale Power Systems, Wenxin Liu, Jagannathan Sarangapani, Ganesh K. Venayagamoorthy, Donald C. Wunsch, Mariesa Crow, David A. Cartes

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents two neural network (NN) based decentralized controller designs for large scale power systems' generators, one is for the excitation control and the other is for the steam valve control. Though the control signals are calculated using local signals only, the transient and overall system stabilities can be guaranteed. NNs are used to approximate the unknown and/or imprecise dynamics of the local power system and the interconnection terms, thus the requirements for exact system parameters are released. Simulation studies with a three machine power system demonstrate the effectiveness of the proposed controller designs.

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Evaluation Of Time Independent Rheological Models Applicable To Fresh Self-Compacting Concrete, Dimitri Feys, Ronny Verhoeven, Geert De Schutter Jan 2007

Evaluation Of Time Independent Rheological Models Applicable To Fresh Self-Compacting Concrete, Dimitri Feys, Ronny Verhoeven, Geert De Schutter

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Self-Compacting Concrete is a New Type of Concrete Which is More Liquid Compared to Traditional Concrete and Which Does Not Need Any Form of External Compaction. as a Result, This Type of Concrete is Suitable for a New Placing Technique: Pumping SCC from the Bottom in the Formwork and Letting It Rise in the Formwork Due to the Applied Pressure. in Order to Understand the Phenomena Occurring during Pumping Operations, the Rheological Properties of SCC Must Be Investigated and Controlled. Tests Have Been Performed with Two Different Rheometers, Which Are Described in This Paper. for the Tattersall MIk-II Rheometer, a …

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Characterizing The Electric Field Coupling From Ic Heatsink Structures To External Cables Using Tem Cell Measurements, Shaowei Deng, Todd H. Hubing, Daryl G. Beetner Jan 2007

Characterizing The Electric Field Coupling From Ic Heatsink Structures To External Cables Using Tem Cell Measurements, Shaowei Deng, Todd H. Hubing, Daryl G. Beetner

Electrical and Computer Engineering Faculty Research & Creative Works

One method for evaluating the unintentional radiated emissions from integrated circuits (ICs) involves mounting the IC on a printed circuit board (PCB) embedded in the wall of a transverse electromagnetic (TEM) cell. The signal voltages on the IC and its package produce electric fields that can couple to cables and other structures attached to the PCB, inducing common-mode currents that can be a primary source of unintentional radiated emissions. The signal currents in the IC and its package produce magnetic fields that can also result in common-mode currents on larger radiating structures. This paper describes a TEM cell measurement method …

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Frequency-Domain Channel Estimation And Equalization For Broadband Wireless Communications, Y. Rosa Zheng, Chengshan Xiao Jan 2007

Frequency-Domain Channel Estimation And Equalization For Broadband Wireless Communications, Y. Rosa Zheng, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

Frequency-domain equalization (FDE) is an effective technique for high data rate wireless communication systems suffering from very long intersymbol interference. Most of existing FDE algorithms are limited to quasi-static or slow time-varying fading channels, where least mean squares (LMS) or recursive least squares (RLS) adaptive algorithms were utilized for channel estimation. In this paper, we employ interpolation method to develop channel estimation algorithm in the frequency domain. We show that the new channel estimation algorithm can significantly outperform LMS and RLS algorithms. Numerical examples demonstrate that the new algorithm can track time-varying fading channels with Doppler up to 300-400 Hz. …

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Demodulation Of Fiber-Optic Sensors For Frequency Response Measurement, Abdeq M. Abdi, Steve Eugene Watkins Jan 2007

Demodulation Of Fiber-Optic Sensors For Frequency Response Measurement, Abdeq M. Abdi, Steve Eugene Watkins

Electrical and Computer Engineering Faculty Research & Creative Works

The neural-network-based processing of extrinsic Fabry-Perot interferometric (EFPI) strain sensors was investigated for the special case of sinusoidal strain. The application area is modal or cyclic testing of structures in which the frequency response to periodic actuation must be demodulated. The nonlinear modulation characteristic of EFPI sensors produces well-defined harmonics of the actuation frequency. Relationships between peak strain and harmonic content were analyzed theoretically. A two-stage demodulator was implemented with a Fourier series neural network to separate the harmonic components of an EFPI signal and a backpropagation neural network to predict the peak-to-peak strain from the harmonics. The system performance …

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Improvement Of Can Bus Performance By Using Error-Correction Codes, Krishna Chaitanya Emani, Maciej Jan Zawodniok, Y. Rosa Zheng, Jagannathan Sarangapani, Keong W. Kam Jan 2007

Improvement Of Can Bus Performance By Using Error-Correction Codes, Krishna Chaitanya Emani, Maciej Jan Zawodniok, Y. Rosa Zheng, Jagannathan Sarangapani, Keong W. Kam

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, two variants of the Hybrid Automatic Repeat Request (HARQ) scheme for CAN bus are presented. The basic HARQ uses error-correction code based on the Reed- Solomon (RS) technique and the Cyclic Redundancy Check (CRC) method to detect errors. The second scheme uses the cyclic error-correction method instead of the CRC error-detection method to further improve the throughput. Moreover, the second scheme uses no additional bit overhead when compared with the basic HARQ scheme. This paper presents the performance of the proposed schemes using MATLAB and NS2 simulations. Experimental data of error patterns were used for realistic evaluation. …

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Near Optimal Output-Feedback Control Of Nonlinear Discrete-Time Systems In Nonstrict Feedback Form With Application To Engines, Peter Shih, Brian C. Kaul, Jagannathan Sarangapani, J. A. Drallmeier Jan 2007

Near Optimal Output-Feedback Control Of Nonlinear Discrete-Time Systems In Nonstrict Feedback Form With Application To Engines, Peter Shih, Brian C. Kaul, Jagannathan Sarangapani, J. A. Drallmeier

Electrical and Computer Engineering Faculty Research & Creative Works

A novel reinforcement-learning based output-adaptive neural network (NN) controller, also referred as the adaptive-critic NN controller, is developed to track a desired trajectory for a class of complex nonlinear discrete-time systems in the presence of bounded and unknown disturbances. The controller includes an observer for estimating states and the outputs, critic, and two action NNs for generating virtual, and actual control inputs. The critic approximates certain strategic utility function and the action NNs are used to minimize both the strategic utility function and their outputs. All NN weights adapt online towards minimization of a performance index, utilizing gradient-descent based rule. …

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Reinforcement Learning Based Output-Feedback Controller For Complex Nonlinear Discrete-Time Systems, Peter Shih, Jagannathan Sarangapani Jan 2007

Reinforcement Learning Based Output-Feedback Controller For Complex Nonlinear Discrete-Time Systems, Peter Shih, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

A novel reinforcement-learning based output-adaptive neural network (NN) controller, also referred as the adaptive-critic NN controller, is developed to track a desired trajectory for a class of complex feedback nonlinear discrete-time systems in the presence of bounded and unknown disturbances. This nonlinear discrete-time system consists of a second order system in nonstrict form and an affine nonlinear discrete-time system tightly coupled together. Two adaptive critic NN controllers are designed - primary one for the nonstrict system and the secondary one for the affine system. A Lyapunov function shows the uniformly ultimate boundedness (UUB) of the closed-loop tracking error, weight estimates …

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