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Articles 11791 - 11820 of 21751

Full-Text Articles in Engineering

Development And Implementation Of Optimized Energy-Delay Sub-Network Routing Protocol For Wireless Sensor Networks, Maciej Jan Zawodniok, Jagannathan Sarangapani, Steve Eugene Watkins, James W. Fonda Jan 2006

Development And Implementation Of Optimized Energy-Delay Sub-Network Routing Protocol For Wireless Sensor Networks, Maciej Jan Zawodniok, Jagannathan Sarangapani, Steve Eugene Watkins, James W. Fonda

Electrical and Computer Engineering Faculty Research & Creative Works

The development and implementation of the optimized energy-delay sub-network routing (OEDSR) protocol for wireless sensor networks (WSN) is presented. This ondemand routing protocol minimizes a novel link cost factor which is defined using available energy, end-to-end (E2E) delay and distance from a node to the base station (BS), along with clustering, to effectively route information to the BS. Initially, the nodes are either in idle or sleep mode, but once an event is detected, the nodes near the event become active and start forming sub-networks. Formation of the inactive network into a sub-network saves energy because only a portion of …


Distributed Power Control For Cellular Networks In The Presence Of Channel Uncertainties, Maciej Jan Zawodniok, Q. Shang, Jagannathan Sarangapani Jan 2006

Distributed Power Control For Cellular Networks In The Presence Of Channel Uncertainties, Maciej Jan Zawodniok, Q. Shang, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a novel distributed power control (DPC) scheme for cellular network in the presence of radio channel uncertainties such as path loss, shadowing, and Rayleigh fading is presented. Since these uncertainties can attenuate the received signal strength and can cause variations in the received Signal-to-Interference ratio (SIR), a new DPC scheme, which can estimate the slowly varying channel uncertainty, is proposed so that a target SIR at the receiver can be maintained. Further, the standard assumption of a constant interference during a link's power update used in other works in the literature is relaxed. A CDMA-based cellular network …


Gene Expression Data For Dlbcl Cancer Survival Prediction With A Combination Of Machine Learning Technologies, Rui Xu, Xindi Cai, Donald C. Wunsch Jan 2006

Gene Expression Data For Dlbcl Cancer Survival Prediction With A Combination Of Machine Learning Technologies, Rui Xu, Xindi Cai, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

Gene expression profiles have become an important and promising way for cancer prognosis and treatment. In addition to their application in cancer class prediction and discovery, gene expression data can be used for the prediction of patient survival. Here, we use particle swarm optimization (PSO) to address one of the major challenges in gene expression data analysis, the curse of dimensionality, in order to discriminate high risk patients from low risk patients. A discrete binary version of PSO is used for gene selection and dimensionality reduction, and a probabilistic neural network (PNN) is implemented as the classifier. The experimental results …


Intelligent Optimal Control Of Excitation And Turbine Systems In Power Networks, Ganesh K. Venayagamoorthy, Ronald G. Harley Jan 2006

Intelligent Optimal Control Of Excitation And Turbine Systems In Power Networks, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

The increasing complexity of the modern power grid highlights the need for advanced modeling and control techniques for effective control of excitation and turbine systems. The crucial factors affecting the modern power systems today is voltage control and system stabilization during small and large disturbances. Simulation studies and real-time laboratory experimental studies carried out are described and the results show the successful control of the power system excitation and turbine systems with adaptive and optimal neurocontrol approaches. Performances of the neurocontrollers are compared with the conventional PI controllers for damping under different operating conditions for small and large disturbances.


Laser Optical In-Circuit Measurement System For Immunity Applications, Chong Ding, David Pommerenke Jan 2006

Laser Optical In-Circuit Measurement System For Immunity Applications, Chong Ding, David Pommerenke

Electrical and Computer Engineering Faculty Research & Creative Works

During immunity testing (ESD, EFT) of a digital circuit, the waveforms of critical signal nets need to be measured for analyzing the failure mechanism. However, it is difficult to measure the induced voltage in the circuit under test due to the unwanted coupling by the non-ideal shielding of the probe cable, especially, if large common mode currents are present. Fiber optical connection avoids this problem. Semiconductor lasers have frequently been used for converting the voltage into an optical signal. The paper shows novel implementations of powering the laser, leading to a small, low cost optical probe.


Optimal Design Of Svc Damping Controllers With Wide Area Measurements Using Small Population Based Pso, Ganesh K. Venayagamoorthy, Tridib Kumar Das, Sandhya R. Jetti Jan 2006

Optimal Design Of Svc Damping Controllers With Wide Area Measurements Using Small Population Based Pso, Ganesh K. Venayagamoorthy, Tridib Kumar Das, Sandhya R. Jetti

Electrical and Computer Engineering Faculty Research & Creative Works

Static Var Compensator (SVC) are employed for providing better voltage regulation and transient stability especially for increased power transfer through the transmission lines. In this paper, two SVC damping controllers with single and dual inputs respectively are designed based on wide area measurements of generator speed deviations. A Small Population based Particle Swarm Optimization algorithm (SPPSO) is applied to determine the optimal parameters of the damping controllers for small and large disturbances. Simulation results are provided to show that the effectiveness of the optimal damping controllers on the Kundur''s two-area benchmark power system. Results show the dual input controller further …


Particle Swarm Optimization Based Defensive Islanding Of Large Scale Power System, Wenxin Liu, Ganesh K. Venayagamoorthy, David A. Cartes Jan 2006

Particle Swarm Optimization Based Defensive Islanding Of Large Scale Power System, Wenxin Liu, Ganesh K. Venayagamoorthy, David A. Cartes

Electrical and Computer Engineering Faculty Research & Creative Works

Defensive islanding is an efficient way to avoid catastrophic failures and wide area blackouts. Power system splitting especially for large scale power systems is a combinatorial explosion problem. Thus, it is very difficult to find an optimal solution (if one exists) for large scale power system in real time. This paper proposes to utilize the computational efficiency property of Binary Particle Swarm Optimization (BPSO) to find some efficient splitting solutions in limited timeframe. The solutions are optimized based on a cost function considering the balance between real power generation and consumption, the relative importance of customers, the capacities of distribution …


Real-Time Implementation Of A Statcom On A Wind Farm Equipped With Doubly Fed Induction Generators, Wei Qiao, Ganesh K. Venayagamoorthy, Ronald G. Harley Jan 2006

Real-Time Implementation Of A Statcom On A Wind Farm Equipped With Doubly Fed Induction Generators, Wei Qiao, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

Voltage stability is a key issue to achieve the uninterrupted operation of wind farms equipped with doubly fed induction generators (DFIGs) during grid faults. A Static Synchronous Compensator (STATCOM) is applied to a power network which includes a DFIG driven by a wind turbine, for steady state voltage regulation and transient voltage stability support. The control schemes of the DFIG rotor-side converter, grid-side converter and the STATCOM are suitably designed and coordinated. The system is implemented in real-time on a Real-Time Digital Simulator (RTDS®). Results show that the STATCOM improves the transient voltage stability and therefore helps the wind turbine …


Designing And Modeling Of A New Continuous Steelmaking Process, Jörg Peter Jan 2006

Designing And Modeling Of A New Continuous Steelmaking Process, Jörg Peter

Doctoral Dissertations

"Continuous steel production has the potential to lower the cost of steelmaking as compared to current batch operations. However, experiences from past attempts to develop and commercialize continuous steelmaking processes show that there are several engineering hurdles to overcome. The objective of this research was the development of a fully continuous steelmaking process that would incorporate the lessons from past experiences, address the foreseen challenges, and meet the requirements to justify the possible replacement of the current EAF-LMF steelmaking route.

The design of the new process consists of five interconnected vessels. Preheated scrap would be continuously charged, melted, and superheated …


An Analysis And Policy Implications Of Comfort Levels Of Diverse Constituents With Reported Units For Blast Vibrations And Limits: Closing The Communication Gap, Braden Lusk Jan 2006

An Analysis And Policy Implications Of Comfort Levels Of Diverse Constituents With Reported Units For Blast Vibrations And Limits: Closing The Communication Gap, Braden Lusk

Doctoral Dissertations

"Differences exist between public perception of construction blasting and quarry blasting. In general, people are able to tolerate short term inconveniences much better than long term ones. Quarries and other long term mining operations utilizing blasting are coming under increasing public and legislative pressure in the United States. The question being posed for the blasting industry is, "Has our past haste in adopting complex scientific scales and units been detrimental to us?" In other words, are the most palatable things being reported? The goal of this dissertation is to determine whether current units create an atmosphere of discomfort among neighbors …


Direct Microstructure Deposition By Micromirror Direct Patterning And Laser Sintering Of Nanoparticles, Weiya Fang Jan 2006

Direct Microstructure Deposition By Micromirror Direct Patterning And Laser Sintering Of Nanoparticles, Weiya Fang

Masters Theses

"The emerging demand for low cost, medium volume production and flexible micro-fabrication techniques has been advanced by the development of MEMS and limitations of the existing technique. As a promising building block for future MEMS and IC industry, nanoparticles are attracting more and more attention due to their interesting electronic, catalytic and optical properties, which can be finely tuned by varying their size. A novel process for the manufacturing of functional microstructures by modulated laser direct patterning and curing of nanoparticles is presented.

The first part of the thesis aims to understand the possibility and process of using modulated laser …


Neural Network Approach For Obstacle Avoidance In 3-D Environments For Uavs, Vivek Yadav, Xiaohua Wang, S. N. Balakrishnan Jan 2006

Neural Network Approach For Obstacle Avoidance In 3-D Environments For Uavs, Vivek Yadav, Xiaohua Wang, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper a controller design is proposed to get obstacle free trajectories in a three dimensional urban environment for unmanned air vehicles (UAVs). The controller has a two-layer architecture. In the upper layer, vision-inspired Grossberg neural network is proposed to get the shortest distance paths. In the bottom layer, a model predictive control (MPC) based controller is used to obtain dynamically feasible trajectories. Simulation results are presented for to demonstrate the potential of the approach.


Plasma Modeling For Ultrashort Laser Ablation Of Dielectrics, Lan Jiang, Hai-Lung Tsai Jan 2006

Plasma Modeling For Ultrashort Laser Ablation Of Dielectrics, Lan Jiang, Hai-Lung Tsai

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In ultrashort pulse (<10 ps) laser ablation of dielectrics, affected materials are first transformed into absorbing plasma with metallic properties and, then, the subsequent laser-plasma interaction causes material removals. For ultrashort-pulse laser ablation of dielectrics, this study proposes a model using the Fokker-Planck equation for electron density distribution, a plasma model for the optical properties of ionized dielectrics, and quantum treatments for electron heating and relaxation time. The free electron density distribution of the plasma within the pulse duration is then used to determine the ablation crater shape. The predicted threshold fluences and ablation depths for barium aluminum borosilicate and fused silica are in agreement with published experimental data. It is found that the significantly varying optical properties in time and space are the key factors determining the ablation crater shape. The effects of fluence and pulse duration are also studied.


Dynamic Re-Optimization Of A Spacecraft Attitude Controller In The Presence Of Uncertainties, Nishant Unnikrishnan, S. N. Balakrishnan, Radhakant Padhi Jan 2006

Dynamic Re-Optimization Of A Spacecraft Attitude Controller In The Presence Of Uncertainties, Nishant Unnikrishnan, S. N. Balakrishnan, Radhakant Padhi

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Online trained neural networks have become popular in recent years in the design of robust and adaptive controllers for dynamic systems with uncertainties due to their universal function approximation capabilities. This paper discusses a technique that dynamically reoptimizes a Single Network Adaptive Critic (SNAC) based optimal controller in the presence of unmodeled plant uncertainties. The SNAC based optimal controller designed for the nominal plant model no more retains optimality in the presence of uncertainties/unmodeled dynamics that may creep up in the system equations during operation. This calls for a strategy to re-optimize the existing SNAC controller with respect to the …


Neural Network Control Of Spark Ignition Engines With High Egr Levels, A. Singh, Brian C. Kaul, J. A. Drallmeier, Jagannathan Sarangapani, Jonathan B. Vance Jan 2006

Neural Network Control Of Spark Ignition Engines With High Egr Levels, A. Singh, Brian C. Kaul, J. A. Drallmeier, Jagannathan Sarangapani, Jonathan B. Vance

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Research has shown substantial reductions in the oxides of nitrogen (NOx) concentrations by using 10% to 25% exhaust gas recirculation (EGR) in spark ignition (SI) engines [1]. However under high EGR levels the engine exhibits strong cyclic dispersion in heat release which may lead to instability and unsatisfactory performance. A suite of neural network (NN)-based output feedback controllers with and without reinforcement learning is developed to control the SI engine at high levels of EGR even when the engine dynamics are unknown by using fuel as the control input. A separate control loop was designed for controlling EGR levels. The …


Effects Of Welding Current In Gas Metal Arc Welding, Junling Hu, Tai Lung Tsai Jan 2006

Effects Of Welding Current In Gas Metal Arc Welding, Junling Hu, Tai Lung Tsai

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In gas metal arc welding (GMAW), current is one of the most important factors affecting the mode of metal transfer, weld pool dynamics and subsequently the weld quality. in this paper, the comprehensive model recently developed by the authors was used to study the effects of different current levels on the droplet formation, plasma generation, metal transfer, and weld pool dynamics in GMA welding. Two welding currents were studied, including one low current and one high current. at each current level, the transient temperature and velocity distributions of the arc plasma and the molten metal, and the shapes of the …


The Importance Of Using Time Domain To Analyze The Effect Of Decoupling Capacitor Performance On Printed Circuit Boards, Bruce Archambeault, Jay Diepenbrock, Samuel Connor, Liang Xue, Giuseppe Selli Jan 2006

The Importance Of Using Time Domain To Analyze The Effect Of Decoupling Capacitor Performance On Printed Circuit Boards, Bruce Archambeault, Jay Diepenbrock, Samuel Connor, Liang Xue, Giuseppe Selli

Electrical and Computer Engineering Faculty Research & Creative Works

This paper demonstrates the importance of using the time domain to properly analyze decoupling capacitor performance on printed circuit boards as well as ASIC packages, etc. Frequency domain analysis is too limited unless the phase information is used along with the magnitude information. the time domain analysis combines the magnitude and phase information to allow a more accurate analysis of decoupling capacitor distance, decoupling capacitor value, and the effects of connection inductance. the impact of connection inductance is extremely important, and it needs to be included in any decoupling capacitor analysis, since this inductance can easily overshadow low plane impedance …


Transverse Explosive Shock-Wave Compression Of Nd₂Fe₁₄B High-Energy Hard Ferromagnets: Induced Magnetic Phase Transition, Sergey I. Shkuratov, Evgueni F. Talantsev, Jason Baird, Larry L. Altgilbers, Allen H. Stults Jan 2006

Transverse Explosive Shock-Wave Compression Of Nd₂Fe₁₄B High-Energy Hard Ferromagnets: Induced Magnetic Phase Transition, Sergey I. Shkuratov, Evgueni F. Talantsev, Jason Baird, Larry L. Altgilbers, Allen H. Stults

Mining Engineering Faculty Research & Creative Works

Investigations of the magnetic phase state of Nd2Fe14B high-energy hard ferromagnets under the action of an explosive shock wave traveling across the magnetization vector, M, have been performed. We demonstrate that the transverse shock-wave compression of an Nd2Fe14B hard ferromagnet with pressure at the shock wave front of P = 22.3 GPa causes a hard ferromagnet — to — weak magnet phase transition. Due to this phase transition, the magnetostatic energy stored for an indefinite period of time in the Nd2Fe14B ferromagnet is released within a short time interval and can be transformed into pulsed primary power. Based on this …


Bacteria Foraging: A New Tool For Simultaneous Robust Design Of Upfc Controllers, M. Tripathy, S. Mishra, Ganesh K. Venayagamoorthy Jan 2006

Bacteria Foraging: A New Tool For Simultaneous Robust Design Of Upfc Controllers, M. Tripathy, S. Mishra, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

Robust tuning of lead-lag type controller used for regulating FACTS control signal to improve dynamic stability has been an area of interest in research. This paper presents a new approach based on the foraging behavior of E. coli Bacteria in the human intestine, to optimize simultaneously three constants each of four lead-lag type UPFC controller present in a Single Machine Infinite Bus (SMIB) power system. For the tuning purpose, a multi-objective cost function is formulated that accounts for damping factors and ratios of various system modes for a wide range of operating conditions. Robustness of the proposed tuning method is …


An Internet Based Intelligent Argumentation System For Collaborative Engineering Design, Xiaoqing Frank Liu, Samir Raorane, Man Zheng, Ming-Chuan Leu Jan 2006

An Internet Based Intelligent Argumentation System For Collaborative Engineering Design, Xiaoqing Frank Liu, Samir Raorane, Man Zheng, Ming-Chuan Leu

Computer Science Faculty Research & Creative Works

Modern product design is a very complicated process which involves groups of designers, manufacturers, suppliers, and customer representatives. Conflicts are unavoidable in collaboration among multiple stakeholders, who have different objectives, requirements, and priorities. Unfortunately, current web-based collaborative engineering design systems do not support collaborative conflict resolution. In this paper, we will develop an intelligent computational argumentation model to enable management of a large scale argumentation network, and resolution of conflicts based on argumentation from many participants. A web-based intelligent argumentation tool is developed as a part of a web-based collaborative engineering design system based on the above model to resolve …


A Methodology For Deriving System Requirements Using Agent Based System Modeling, Karthik Gopalakrishnan, Sreeram Ramakrishnan, Cihan H. Dagli Jan 2006

A Methodology For Deriving System Requirements Using Agent Based System Modeling, Karthik Gopalakrishnan, Sreeram Ramakrishnan, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

In this paper, we duscuss a method to derive the requirements for developing an Industrial Automation and Constrol System (IACS). An IACS has software components and associated hardware, which together implement the required monitoring, supervision and control of operations an a production plant. The requirements of such a system are multi-dimensional and may require multiple layers of abstraction. For this domain, we propose an agent-based modeling adopting an agent-based modeling approach is the implicit flexibility afforded by agents and the negotiation techniques that can be implemented to streamline the change management process associated with requirements modeling and analysis. This paper …


A Simulation Framework For Real-Time Management And Control Of Inventory Routing Decisions, Shrikant Jarugumilli, Sreeram Ramakrishnan, Scott Erwin Grasman Jan 2006

A Simulation Framework For Real-Time Management And Control Of Inventory Routing Decisions, Shrikant Jarugumilli, Sreeram Ramakrishnan, Scott Erwin Grasman

Engineering Management and Systems Engineering Faculty Research & Creative Works

We consider a logistics network where a single warehouse distributes a single item to multiple retailers. Retailers in the network participate in a Vendor Managed Inventory (VMI) program with the warehouse, where the warehouse is responsible for tracking and replenishing the inventory at various retailer locations. The information update occurs every time a vehicle reaches a location and the decision on the delivery quantity and the next location to visit is made. For a small increase of locations in the network, the state space for the solution increases exponentially, making this problem NP-hard. Thus, we propose a solution methodology where …


Modeling Of Dielectric Mixtures Containing Conducting Inclusions With Statistically Distributed Aspect Ratio, Marina Koledintseva, Sandeep K. R. Chandra, Richard E. Dubroff, Robert W. Schwartz Jan 2006

Modeling Of Dielectric Mixtures Containing Conducting Inclusions With Statistically Distributed Aspect Ratio, Marina Koledintseva, Sandeep K. R. Chandra, Richard E. Dubroff, Robert W. Schwartz

Electrical and Computer Engineering Faculty Research & Creative Works

An analytical model of composites made of a dielectric base and randomly oriented metal inclusions in the form of nanorods is presented. This model is based on the generalized Maxwell Garnett (MG) mixing rule. In this model, the nanorod particles are modeled as prolate spheroids with a statistically normal distribution of their aspect ratios. It is shown that parameters of the distribution laws affect the frequency characteristics of the composites both at microwave and optical frequencies. The results of computations are represented.


Surface Modification Of Su-8 By Photografting Of Functional Polymers For Lab-On-A-Chip Applications, Zhan Gao, David Henthorn, Chang-Soo Kim Jan 2006

Surface Modification Of Su-8 By Photografting Of Functional Polymers For Lab-On-A-Chip Applications, Zhan Gao, David Henthorn, Chang-Soo Kim

Chemical and Biochemical Engineering Faculty Research & Creative Works

Due to the high flexibility and versatility in the process development of microfluidic devices, an epoxybased, high-aspect ratio photoresist SU-8 is now attracting attention as the main structuring material of the fluidic channels. Manipulation of the surface properties of SU-8 channel wall is critical to attach functional films such as enzyme-immobilized layers or biocompatible layers. We describe a new in situ patterning method to form a hydrogel film on SU-8 by a photografted polymerization procedure. The hydrophobic surface of SU-8 is modified using a surface bound initiator HCPK (1-hydroxycyclohexyl phenyl ketone). A p-HEMA (poly-2-hydroxyethylmethacrylate) hydrogel film is grafted by photopolymerization …


Recurrent Neural Network Based Predictions Of Elephant Migration In A South African Game Reserve, Parviz Palangpour, Ganesh K. Venayagamoorthy, Kevin Duffy Jan 2006

Recurrent Neural Network Based Predictions Of Elephant Migration In A South African Game Reserve, Parviz Palangpour, Ganesh K. Venayagamoorthy, Kevin Duffy

Electrical and Computer Engineering Faculty Research & Creative Works

A large portion of South Africa''s elephant population can be found on small wildlife reserves. When confined to enclosed reserves the elephant densities are much higher than observed in the wild. The large nutritional demands and destructive foraging behavior of elephants threaten rare species of vegetation. If conservation management is to protect threatened species of vegetation, knowing how long elephants will stay in one area of the reserve as well as which area they will move to next is essential. The goal of this study is to train a recurrent neural network (RNN) to continuously predict an elephant herd''s next …


Simulation Model For Assessing Transient Performance Of Capacitive Voltage Transformers, I. Sule, Ganesh K. Venayagamoorthy, U. O. Aliyu Jan 2006

Simulation Model For Assessing Transient Performance Of Capacitive Voltage Transformers, I. Sule, Ganesh K. Venayagamoorthy, U. O. Aliyu

Electrical and Computer Engineering Faculty Research & Creative Works

In determining the correct operation of relays of a protection scheme, proper representation of instrument transformers and their behavior in conditions where there can be transient is very critical. This paper presents a simulation model for assessing the transient performance of capacitive voltage transformers (CVTs). In order to test the validity of the developed model, four CVT operational conditions are considered using field data collected from one of the Nigerian electric utility 330/132/33 kV substations. The model simulation results revealed various configuration performance responses that could affect relay protection schemes to different degrees. As expected, the CVT responses showed that …


Synthesis And Characterization Of Nanocrystalline (Zr₀.₈₄Y₀.₁₆)O₁.₉₂-(Ce₀.₈₅Sm₀.₁₅)O₁.₉₂₅ Heterophase Thin Films, Aniruddha Kulkarni, Alexander Bourandas, Junhang Dong, Paul A. Fuierer, Hai Xiao Jan 2006

Synthesis And Characterization Of Nanocrystalline (Zr₀.₈₄Y₀.₁₆)O₁.₉₂-(Ce₀.₈₅Sm₀.₁₅)O₁.₉₂₅ Heterophase Thin Films, Aniruddha Kulkarni, Alexander Bourandas, Junhang Dong, Paul A. Fuierer, Hai Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

A new type of nanocrystalline samarium-doped-ceria/yttrium-stabilized-zirconia (SDC/YSZ) heterophase thin film electrolytes was synthesized on MgO and Si substrates by spin coating and thermal treatment of SDC-nanoparticle-incorporated polymeric precursors. In the heterophase films, SDC nanoparticles were uniformly dispersed in a nanocrystalline YSZ matrix. The heterophase structure was stable when fired in air at temperatures up to 850 °C. The nanocrystalline heterophase thin films exhibited electrical conductivities significantly higher than that of the phase-pure YSZ and SDC nanocrystalline thin films at reduced temperatures. The effects of SDC grain size and volume fraction on the electrical conductivity of the heterophase films were also …


Ac/Dc Power Systems With Applications In Future Human Habitat On Lunar And Mars Bases, Badrul H. Chowdhury, Sabbir A. Hossain, James T. Lawrence, Sushant Barave Jan 2006

Ac/Dc Power Systems With Applications In Future Human Habitat On Lunar And Mars Bases, Badrul H. Chowdhury, Sabbir A. Hossain, James T. Lawrence, Sushant Barave

Electrical and Computer Engineering Faculty Research & Creative Works

As NASA readies itself for new space exploration initiatives starting with a human return to the Moon by the year 2020 eventually leading to human exploration of Mars, the requirements for a safe, efficient and comprehensive power system to support the exploration missions as well human habitat will become important issues to consider. Certain issues dealing with electric power generation and distribution on board Mars-bound vehicles and those on Lunar and Martian surfaces are described. The requirements for lightweight power generation dictates the use of a high frequency ac machine. Preliminary results of investigating the design of a permanent magnet …


Adaptive Critic Designs Based Coupled Neurocontrollers For A Static Compensator, Salman Mohagheghi, Ganesh K. Venayagamoorthy, Ronald G. Harley Jan 2006

Adaptive Critic Designs Based Coupled Neurocontrollers For A Static Compensator, Salman Mohagheghi, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

A novel nonlinear optimal neurocontroller for a static compensator (STATCOM) connected to a power system, using artificial neural networks, is presented in this paper. The heuristic dynamic programming (HDP) method, a member of the adaptive critic designs (ACD) family, is used for the design of the STATCOM neurocontroller. The proposed controller is a nonlinear optimal controller that provides coupled control for the line voltage and the dc link voltage regulation loops of the STATCOM. An action dependent approach is used, in which the controller is independent of a model of the network. Moreover, a proportional-integrator approach allows the neurocontroller to …


Adaptive Distributed Fair Scheduling And Its Implementation In Wireless Sensor Networks, Maciej Jan Zawodniok, Jagannathan Sarangapani, Steve Eugene Watkins, James W. Fonda Jan 2006

Adaptive Distributed Fair Scheduling And Its Implementation In Wireless Sensor Networks, Maciej Jan Zawodniok, Jagannathan Sarangapani, Steve Eugene Watkins, James W. Fonda

Electrical and Computer Engineering Faculty Research & Creative Works

A novel adaptive and distributed fair scheduling (ADFS) scheme for wireless sensor networks is shown through hardware implementation. In contrast to simulation, hardware evaluation provides valuable feedback to protocol and hardware development process. The proposed protocol focuses on quality-of-service (QoS) issues to address flow prioritization. Thus, when nodes access a shared channel, the proposed ADFS allocates the channel bandwidth proportionally to the weight, or priority, of the packet flows. Moreover, ADFS allows for dynamic allocation of network resources with little added overhead. Weights are initially assigned using user specified QoS criteria. These weights are subsequently updated as a function of …