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Articles 11341 - 11370 of 13804

Full-Text Articles in Engineering

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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Near Optimal Neural Network-Based Output Feedback Control Of Affine Nonlinear Discrete-Time Systems, Qinmin Yang, Jagannathan Sarangapani Jan 2007

Near Optimal Neural Network-Based Output Feedback Control Of Affine Nonlinear Discrete-Time Systems, Qinmin Yang, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a novel online reinforcement learning neural network (NN)-based optimal output feedback controller, referred to as adaptive critic controller, is proposed for affine nonlinear discrete-time systems, to deliver a desired tracking performance. The adaptive critic design consist of three entities, an observer to estimate the system states, an action network that produces optimal control input and a critic that evaluates the performance of the action network. The critic is termed adaptive as it adapts itself to output the optimal cost-to-go function which is based on the standard Bellman equation. By using the Lyapunov approach, the uniformly ultimate boundedness …

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Online Reinforcement Learning Neural Network Controller Design For Nanomanipulation, Qinmin Yang, Jagannathan Sarangapani Jan 2007

Online Reinforcement Learning Neural Network Controller Design For Nanomanipulation, Qinmin Yang, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a novel reinforcement learning neural network (NN)-based controller, referred to adaptive critic controller, is proposed for affine nonlinear discrete-time systems with applications to nanomanipulation. In the online NN reinforcement learning method, one NN is designated as the critic NN, which approximates the long-term cost function by assuming that the states of the nonlinear systems is available for measurement. An action NN is employed to derive an optimal control signal to track a desired system trajectory while minimizing the cost function. Online updating weight tuning schemes for these two NNs are also derived. By using the Lyapunov approach, …

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Developing A Spatial Interface For Information Visualization And Management In A Crisis Response Scenario, Anthony Costello Jan 2007

Developing A Spatial Interface For Information Visualization And Management In A Crisis Response Scenario, Anthony Costello

Electronic Theses and Dissertations

The focus of this study was to investigate how a spatial interface can be effectively utilized to support information presentation and information integration via human-centric data visualization, leading to decreased cognitive load, more accurate situation awareness, and subsequently, improved task performance. In high tempo, information intensive environments like those managed by an emergency operations center (EOC), information organization tools are essential. Though users can be trained to use conventional email software applications efficiently, the constraints of the information management paradigms inherent to conventional systems may limit a user's ability to gather context and create an accurate picture of the situation. …

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Using Surrogate Measures To Predict Patient Satisfaction In The Emergency Department, Erica Egri Jan 2007

Using Surrogate Measures To Predict Patient Satisfaction In The Emergency Department, Erica Egri

Electronic Theses and Dissertations

With healthcare organizations struggling to remain competitive and financially stable in a market where minimizing costs is a priority, hospital administrators feel the sense of urgency when it comes to keeping patients satisfied with services in order to expand volume and market share. The Emergency Department is considered the front door of a healthcare organization, and keeping its visitors satisfied in order to guarantee a future visit or a referral to a friend or family member is a must. While patient input on the services received in a healthcare facility is essential to improving quality of care, the costs associated …

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Buffer Techniques For Stochastic Resource Constrained Project Scheduling With Stochastic Task Insertions Problems, Jennifer Grey Jan 2007

Buffer Techniques For Stochastic Resource Constrained Project Scheduling With Stochastic Task Insertions Problems, Jennifer Grey

Electronic Theses and Dissertations

Project managers are faced with the challenging task of managing an environment filled with uncertainties that may lead to multiple disruptions during project execution. In particular, they are frequently confronted with planning for routine and non-routine unplanned work: known, identified, tasks that may or may not occur depending upon various, often unpredictable, factors. This problem is known as the stochastic task insertion problem, where tasks of deterministic duration occur stochastically. Traditionally, project managers may include an extra margin within deterministic task times or an extra time buffer may be allotted at the end of the project schedule to protect the …

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Mass Customization Strategies And Their Relationship To Lean Production In The Homebuilding Industry, Isabelina Nahmens Jan 2007

Mass Customization Strategies And Their Relationship To Lean Production In The Homebuilding Industry, Isabelina Nahmens

Electronic Theses and Dissertations

Current housing trends point to an increasing interest from homebuyers to demand houses that reflect their personal and unique styles, and which are individually configured according to these needs (NAHB, 2004). These homebuyers in turn are unwilling to settle for standard models that sacrifice what they really want in a home. At the same time this creates pressure on builders who are reluctant to sacrifice production efficiencies by deviating from standard models. Such customization desired by demanding customers can disrupt the entire estimating, production, delivery and management process, making it even more difficult to manage homebuilding efficiently and effectively. The …

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Optimizing The Design Of Multimodal User Interfaces, Leah Reeves Jan 2007

Optimizing The Design Of Multimodal User Interfaces, Leah Reeves

Electronic Theses and Dissertations

Due to a current lack of principle-driven multimodal user interface design guidelines, designers may encounter difficulties when choosing the most appropriate display modality for given users or specific tasks (e.g., verbal versus spatial tasks). The development of multimodal display guidelines from both a user and task domain perspective is thus critical to the achievement of successful human-system interaction. Specifically, there is a need to determine how to design task information presentation (e.g., via which modalities) to capitalize on an individual operator's information processing capabilities and the inherent efficiencies associated with redundant sensory information, thereby alleviating information overload. The present effort …

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Cognitive Learning From Computer-Based Information Systems By Incorporating Knowledge Construction Interventions, Wajdi Wazzan Jan 2007

Cognitive Learning From Computer-Based Information Systems By Incorporating Knowledge Construction Interventions, Wajdi Wazzan

Electronic Theses and Dissertations

The aim of the present study was to develop and empirically evaluate different categories of instructional activities, which stimulate the generation and construction of knowledge on the part of an individual student. These generative activities are primed by prompts or scaffolds, which can easily be inserted into specific curriculum addressing any domain of knowledge. To assess the manner in which the knowledge construction interventions influence the learning outcomes from computerized information systems, we have developed an online computer-based information system that describes the functions and mechanisms associated with the bus system of the US army Abrams M1A2 tank. Seven versions …

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Management Systems Fit For Organizational Performance, Rey Diaz Jan 2007

Management Systems Fit For Organizational Performance, Rey Diaz

Electronic Theses and Dissertations

The present study identifies the dimensions and variables using prior research within each of the constructs under the management systems, fit and, organizational strategy, structure, lifecycle and performance. The constructs from the research model were defined with a combination of direct, calculated and coded measures. Context analysis for each case categorized management systems design into either prescriptive or descriptive. The selected performance measures have been extensively investigated in the research fields associated with organizational management. The study uses the multiple case study design with cross-sectional data spanning from 1991 to 2005 and involving 19 aerospace companies in the United States. …

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An Optimal Operational Policy For An Integrated Production-Delivery System Under Continuous Price Decrease, Deniz Mungan Jan 2007

An Optimal Operational Policy For An Integrated Production-Delivery System Under Continuous Price Decrease, Deniz Mungan

LSU Master's Theses

In today’s competitive world, the unit cost of a high-tech product declines significantly over its life cycle. An integrated inventory model for products experiencing continuous decrease in unit cost is studied in this research. In this integrated model a manufacturing facility purchases raw material from outside supplier at a fixed size and supplies a fixed quantity of finished products to a buyer periodically after using its production processes. Moreover, buyers demand frequent deliveries of small lots of finished products since the price is continuously decreasing, and this emphasizes the significance of just-in-time (JIT) inventory management for successful companies in technology-related …

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Development And Implementation Of The Bring Your Own Water Treatment System In Dense, Rural, And Mountainous Rwandan Communities, Maximilian Gold, Evan A. Thomas, Richard L. Byyny, Jean Pierre Habanabakize Jan 2007

Development And Implementation Of The Bring Your Own Water Treatment System In Dense, Rural, And Mountainous Rwandan Communities, Maximilian Gold, Evan A. Thomas, Richard L. Byyny, Jean Pierre Habanabakize

Mechanical and Materials Engineering Faculty Publications and Presentations

Over a billion people in the world lack access to safe drinking water1. While numerous technological, medical, and educational solutions have been implemented for the benefit of disadvantaged communities, there is no 'magic bullet'. Instead, development agencies must partner directly with these communities to address their public health needs through appropriate technology solutions, backed up by education and assessment. The "Bring Your Own Water (BYOW) Treatment System" developed by the Engineers Without Borders-USA chapters at the University of Colorado at Boulder Chapter (EWB-CU) and the Johnson Space Center (EWB-JSC) is uniquely designed to address the water treatment requirements of two …

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Towards A Diagnostic Framework For Understanding Complex Situations, José J. Padilla, Andres Sousa-Poza, Arturo Tejada, Samuel Kovacic Jan 2007

Towards A Diagnostic Framework For Understanding Complex Situations, José J. Padilla, Andres Sousa-Poza, Arturo Tejada, Samuel Kovacic

VMASC Publications

This paper presents a theoretical framework for the concept of understanding and how it can be used for assessing complex situations. Understanding is presented as a cognitive process on how an individual perceives and represents a complex domain based on his/her own predispositions, and how he/she selects knowledge or what may not be knowledge based on the same predispositions towards finding a set of solutions for the situation. Predispositions, in this case, are based on his/her epistemological, ontological and teleological biases while the domain is represented by irreducible and transient conditions. The final outcome is the match or mismatch of …

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Converting Some Global Optimization Problems To Mixed Integer Linear Problems Using Piecewise Linear Approximations, Manish Kumar Jan 2007

Converting Some Global Optimization Problems To Mixed Integer Linear Problems Using Piecewise Linear Approximations, Manish Kumar

Masters Theses

"Some global optimization problems are converted to mixed-integer linear problems (MILP) using piecewise-linear approximations in this thesis so that they can be solved using commercial MILP solvers, such as CPLEX. Special attention is given to approximating two-term log-sum functions, which appears frequently in generalized geometric programming problems. Numerical results indicate the proposed approach is sound and efficient"--Abstract, page iii.

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Best Practices For Implementing A Biodiesel Program, Sundaresan Sadashivam Jan 2007

Best Practices For Implementing A Biodiesel Program, Sundaresan Sadashivam

Masters Theses

"The Missouri Department of Transportation (MoDOT) has a mandate to utilize biodiesel blends in its fleets. However, they have not been able to meet this requirement due to various implementation issues. Therefore, this thesis presents a study to determine the best practices for implementing a biodiesel program. The study was conducted by soliciting information from Departments of Transportation and other agencies related to their biodiesel programs and practices. A list of best practices was developed and the Analytic Hierarchy Process (AHP) was used to prioritize this list of best practices"--Abstract, page iv.

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Security Architecture Methodology For Large Net-Centric Systems, Njideka Adaku Umeh Jan 2007

Security Architecture Methodology For Large Net-Centric Systems, Njideka Adaku Umeh

Masters Theses

"This thesis describes an over-arching security architecture methodology for large network enabled systems that can be scaled down for smaller network centric operations such as present at the University of Missouri-Rolla. By leveraging the five elements of security policy & standards, security risk management, security auditing, security federation and security management, of the proposed security architecture and addressing the specific needs of UMR, the methodology was used to determine places of improvement for UMR"--Abstract, page iii.

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Use Of Analytical Hierarchy Process In University Strategy Planning, Mihir Gokhale Jan 2007

Use Of Analytical Hierarchy Process In University Strategy Planning, Mihir Gokhale

Masters Theses

"The selection of an appropriate strategy is critical for a university's success, and each university needs to capitalize on its own specialties and competencies for a competitive advantage. Strategy creation and planning in universities is generally a collective effort which relies on consensus. It is a complex process involving the setting of objectives and goals to achieve the strategic vision, and an analysis tool for evaluating and comparing different options and prioritizing objectives and goals is required. A high deductive capacity is necessary for aggregating the different trade-offs while prioritizing, which is challenging for a human mind. This thesis demonstrates …

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Bridge Damage Detection Using An Intelligent Engineering System, Dionysios N. Danilatos Jan 2007

Bridge Damage Detection Using An Intelligent Engineering System, Dionysios N. Danilatos

Masters Theses

"This thesis concerns the design of an algorithm that is capable to detect structural damage in civil infrastructure bridges. The algorithm, which will be dubbed Damage Diagnostics System throughout the thesis, is the software component of a broader Bridge Health Monitoring System. This broader system integrates software and hardware,such as sensors and data acquisition components...The rationale for the Structural Damage Diagnosis is based on the principle of the structural vibration testing. The Health Monitoring System captures the vibration signals, as the bridge responds to excitation from various sources. The purpose of the Diagnostic System is to extract information from the …

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Barriers And Best Practices For Material Management In The Healthcare Sector, Carlos Callender Jan 2007

Barriers And Best Practices For Material Management In The Healthcare Sector, Carlos Callender

Masters Theses

"For many years, the primary focus of the healthcare sector has been to provide patients with the best quality of care. Recently, with the escalating cost of supplies and the severe competition among healthcare providers, the pressure on material managers to operate more cost-efficiently without compromising the high patient care standards has significantly increased. While other sectors have experienced success through the deployment of supply chain management practices, the healthcare sector has not seen major improvements in this area. However, in spite of the uniqueness and complexity of the healthcare supply chain, opportunities for improvements are plentiful. Thus, this thesis …

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Integrated Product And Its Extended Enterprise Network Design Using Lean Principles, Abhijit K. Choudhury Jan 2007

Integrated Product And Its Extended Enterprise Network Design Using Lean Principles, Abhijit K. Choudhury

Masters Theses

"Recently, many system integration companies have begun to intensely focus on suppliers' involvement in the product realization process to enhance their competitiveness. The product architecture has a huge impact on the efficiency of the integrator's supplier network. One of the ways to enhance efficiency is to implement the lean principles while creating a collaborative design/manufacturing/supply chain environment. In this study, two distinct stages of the product realization process, namely, design stage and production stage are considered for determining the design and production supplier networks"--Abstract, page iv.

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Modular Architecting For Effects Based Operations, Emel Meteoglu Jan 2007

Modular Architecting For Effects Based Operations, Emel Meteoglu

Masters Theses

"Effects Based Operations (EBO) is a way of thinking for planning, executing and assessing any operations for the effects they produce, rather than dealing with actions, targets or even objectives. The literature on EBO has been growing day by day; however, there is still a need for modeling techniques and tools that provide more efficient and effective effects based assessment, planning and analysis in order to further develop the capabilities of the operations. In this context, this thesis presents an introduction to EBO by focusing on its methodology, its challenges and also its applicability in different systems. Moreover, this thesis …

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Enhanced Functional Analysis System Technique For Managing Complex Engineering Projects, Sofia Tan Jan 2007

Enhanced Functional Analysis System Technique For Managing Complex Engineering Projects, Sofia Tan

Masters Theses

"This study presents an Enhanced Functional Analysis Systems Technique (EFAST) tool to facilitate communication amongst various stakeholders such as the customers, program managers, systems architects, and systems engineers. the EFAST maps the customer requirements to downstream system functions and subsystem/component requirements, and outlines the interactions between various system and subsystem level and activities using a top-down approach. A bottom-up approach is used to populate the system element cost and time estimates. The EFAST tool compares the budgeted development resources with the estimated development resources to provide a realistic picture for realizing project in terms of performance, cost, and schedule. The …

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Interactive And Dialogue Based Learning In Engineering Education, Siddartha Thummuri Jan 2007

Interactive And Dialogue Based Learning In Engineering Education, Siddartha Thummuri

Masters Theses

"This thesis focuses on a class room architecture that provides high levels of interactivity which enhances the students' learning environment both in distance and on-campus contexts and forms a basis for practical learning. Two analyses are presented in this thesis, the first one being a simple measure of levels of interactivity in this course architecture, based on rubric and the second one, a comparative analysis, to demonstrate the effectiveness of interactive (multi-directional information flow) classrooms as opposed to conventional (unidirectional information flow) classrooms and that this course architecture is ideal for enhancement of distance learning and an excellent route to …

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Executable System Architecting Using Systems Modeling Language In Conjunction With Colored Petri Nets - A Demonstration Using The Geoss Network Centric System, Renzhong Wang Jan 2007

Executable System Architecting Using Systems Modeling Language In Conjunction With Colored Petri Nets - A Demonstration Using The Geoss Network Centric System, Renzhong Wang

Masters Theses

"Models and simulation furnish abstractions to manage complexities allowing engineers to visualize the proposed system and to analyze and validate system behavior before constructing it. Unified Modeling Language (UML) and its systems engineering extension, Systems Modeling Language (SysML), provide a rich set of diagrams for systems specification. However, the lack of executable semantics of such notations limits the capability of analyzing and verifying defined specifications. This research has developed an executable system architecting framework based on SysML-CPN transformation, which introduces dynamic model analysis into SysML modeling by mapping SysML notations to Colored Petri Net (CPN), a graphical language for system …

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Cognitive Biases In Risk Management, William Thomas Siefert Jan 2007

Cognitive Biases In Risk Management, William Thomas Siefert

Masters Theses

"This thesis contends that most Risk Management/Mitigation programs fail to be as effective as they could be due to a number of mostly overlooked drivers, such as motivation and cognitive biases. The issue of cognitive biases is very seldom addressed. When questioned, most engineers purport to not have any biases. They insist that they use only logic, reasoning, and math to make decisions. A set of data was collected and reviewed for this thesis. The data presented shows that cognitive biases do affect the risk management/mitigation process. Knowledge of these biases and their potential impact on a project will lead …

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Design For Auditory Displays: Identifying Temporal And Spatial Information Conveyance Principles, Ali Ahmad Jan 2007

Design For Auditory Displays: Identifying Temporal And Spatial Information Conveyance Principles, Ali Ahmad

Electronic Theses and Dissertations

Designing auditory interfaces is a challenge for current human-systems developers. This is largely due to a lack of theoretical guidance for directing how best to use sounds in today's visually-rich graphical user interfaces. This dissertation provided a framework for guiding the design of audio interfaces to enhance human-systems performance. This doctoral research involved reviewing the literature on conveying temporal and spatial information using audio, using this knowledge to build three theoretical models to aid the design of auditory interfaces, and empirically validating select components of the models. The three models included an audio integration model that outlines an end-to-end process …

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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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Understanding Behavior Of System Of Systems Through Computational Intelligence Techniques, Nil H. Kilicay, Cihan H. Dagli Jan 2007

Understanding Behavior Of System Of Systems Through Computational Intelligence Techniques, Nil H. Kilicay, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

The world is facing an increasing level of systems integration leading towards systems of systems (SoS) that adapt to changing environmental conditions. The number of connections between components, the diversity of the components and the way the components are organized can lead to different emergent system behavior. Therefore, the need to focus on overall system behavior is becoming an unavoidable issue. The problem is to develop methodologies appropriate for better understanding behavior of system of systems before the design and implementation phase. This paper focuses on computational intelligence techniques used for analysis of complex adaptive systems with the aim of …

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Breaking The Cycle-Preventing Failures By Leveraging Historical Data During Conceptual Design, Daniel A. Krus, Katie Grantham Jan 2007

Breaking The Cycle-Preventing Failures By Leveraging Historical Data During Conceptual Design, Daniel A. Krus, Katie Grantham

Engineering Management and Systems Engineering Faculty Research & Creative Works

Major engineering accidents are often caused by seemingly minor failures propagating through complex systems. One example of this is an accident involving a Bell 206 Rotorcraft where a fuel pump failure led to the severing of the tail boom. Cataloguing and communicating the knowledge of potential failures and failure propagations is critical to prevent further accidents. The need for effective failure prevention tools is not specific to rotorcrafts, however. Failure reporting systems have been adopted by various industries to aid and promote failure prevention. The catalogued failures usually consist of narratives describing which part of a product failed, how it …

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Adaptive Power Control Protocol With Hardware Implementation For Wireless Sensor And Rfid Reader Networks, Kainan Cha, Jagannathan Sarangapani, David Pommerenke Jan 2007

Adaptive Power Control Protocol With Hardware Implementation For Wireless Sensor And Rfid Reader Networks, Kainan Cha, Jagannathan Sarangapani, David Pommerenke

Electrical and Computer Engineering Faculty Research & Creative Works

The development and deployment of radio frequency identification (RFID) systems render a novel distributed sensor network which enhances visibility into manufacturing processes. In 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. Consequently, medium access protocols (MAC) protocols are needed for such networks to assess and provide access to the channel so that tags can be read accurately. In this paper, we investigate a suite of feasible power control schemes to ensure overall coverage area of the system while maintaining a …

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