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Optimization

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Articles 961 - 990 of 1216

Full-Text Articles in Engineering

Heuristic Algorithms For Optimization Of Task Allocation And Result Distribution In Peer-To-Peer Computing Systems, Grzegorz Chmaj, Krzysztof Walkowiak, Michal Tarnawski, Michal Kucharzak Sep 2012

Heuristic Algorithms For Optimization Of Task Allocation And Result Distribution In Peer-To-Peer Computing Systems, Grzegorz Chmaj, Krzysztof Walkowiak, Michal Tarnawski, Michal Kucharzak

Electrical & Computer Engineering Faculty Research

Recently, distributed computing system have been gaining much attention due to a growing demand for various kinds of effective computations in both industry and academia. In this paper, we focus on Peer-to-Peer (P2P) computing systems, also called public-resource computing systems or global computing systems. P2P computing systems, contrary to grids, use personal computers and other relatively simple electronic equipment (e.g., the PlayStation console) to process sophisticated computational projects. A significant example of the P2P computing idea is the BOINC (Berkeley Open Infrastructure for Network Computing) project. To improve the performance of the computing system, we propose to use the P2P …

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An Efficient Genetic Algorithm For The Design Optimization Of Cold-Formed Steel Portal Frame Buildings, Duoc T. Phan, James B. P. Lim, Tiku T. Tanyimboh, Wei Sha Aug 2012

An Efficient Genetic Algorithm For The Design Optimization Of Cold-Formed Steel Portal Frame Buildings, Duoc T. Phan, James B. P. Lim, Tiku T. Tanyimboh, Wei Sha

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The design optimization of cold-formed steel portal frame buildings is considered in this paper. The real-coded genetic algorithm (GA) optimizer proposed considers both building’s topology (i.e. frame spacing and pitch) and cross-sectional sizes of the main structural members as the decision variables that are optimized. Previous GAs in the literature were characterized by poor convergence including slow progress that usually results in excessive computation times and/or frequent failure to achieve an optimal or near-optimal solution. This is the main issue addressed in this paper. In an effort to improve the performance of the conventional GA, a niching strategy is presented …

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Advanced Design Optimization Of Cold-Formed Steel Portal Frame Buildings, Duoc T. Phan, James B. P. Lim, Tiku T. Tanyimboh, Wei Sha Aug 2012

Advanced Design Optimization Of Cold-Formed Steel Portal Frame Buildings, Duoc T. Phan, James B. P. Lim, Tiku T. Tanyimboh, Wei Sha

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The design optimization of cold-formed steel portal frame buildings is considered in this paper. The objective function is based on the cost of the members for the main frame and secondary members (i.e., purlins, girts, and cladding for walls and roofs) per unit area on the plan of the building. A realcoded niching genetic algorithm is used to minimize the cost of the frame and secondary members that are designed on the basis of ultimate limit state. It is shown that the proposed algorithm shows effective and robust capacity in generating the optimal solution, owing to the population’s diversity being …

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Optimum Design Of Mufflers Hybridized With One-Connected Curved Tube Using The Boundary Element Method, Neural Networks, And The Genetic Algorithm, Ying-Chun Chang, Min-Chie Chiu, Ching-Chung Hsieh Aug 2012

Optimum Design Of Mufflers Hybridized With One-Connected Curved Tube Using The Boundary Element Method, Neural Networks, And The Genetic Algorithm, Ying-Chun Chang, Min-Chie Chiu, Ching-Chung Hsieh

Journal of Marine Science and Technology–Taiwan

Recently, research on new techniques for an economical muffler, which is hybridized with a single-connected curved tube, has been applied in the industrial field. Most researchers have explored noise reduction effects based on the transfer matrix method and the stiffness matrix method. However, the maximum noise reduction of a silencer within a constrained space, which frequently occurs in engineering problems, has been neglected. Therefore, the optimum design of mufflers becomes an essential issue. In this paper the shape optimization of a one-connected tube muffler with a fixed length is examined. In order to speed up the optimization assessment, a simplified …

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Optimization Models And Algorithms For Truckload Relay Network Design, Hector Andres Vergara Arteaga Aug 2012

Optimization Models And Algorithms For Truckload Relay Network Design, Hector Andres Vergara Arteaga

Graduate Theses and Dissertations

Driver turnover is a significant problem for full truckload (TL) carriers that operate using point-to-point (PtP) dispatching. The low quality of life of drivers due to the long periods of time they spend away from home is usually identified as one of the main reasons for the high turnover. In contrast, driver turnover is not as significant for less-than-truckload (LTL) carriers that use hub-and-spoke transportation networks which allow drivers to return home more frequently. Based on the differences between TL and LTL, the use of a relay network (RN) has been proposed as an alternative dispatching method for TL transportation …

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Multi-Functional Reconfigurable Antenna Development By Multi-Objective Optimization, Xiaoyan Yuan Aug 2012

Multi-Functional Reconfigurable Antenna Development By Multi-Objective Optimization, Xiaoyan Yuan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Antennas are the most essential and significant elements of any wireless communication system. The most common antennas used in wireless communication systems include dipoles/monopoles, horn antennas, loop antennas, and micro-strip antennas. Each type possesses inherent advantages and disadvantages that make them satisfactory for particular applications. The properties of these antennas, however, are fixed by the initial design and cannot be changed. These fixed properties impose restrictions on the overall system performance as the antenna cannot adapt its characteristics in response to the changing propagation parameters of the wireless medium. A reconfigurable antenna, on the other hand, can dynamically change its …

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Generating Minimal T-Wise Test Suites, Luis C. Gutierrez, Carlos Nieto, Francisco Zapata, Martine Ceberio Jul 2012

Generating Minimal T-Wise Test Suites, Luis C. Gutierrez, Carlos Nieto, Francisco Zapata, Martine Ceberio

COURI Symposium Abstracts, Summer 2012

As the use of computing devices increases every day, users rely on the adequate functioning of software. When software is not tested properly, it can yield erroneous information or a complete failure of the system. The NIST estimates that defective software cost the United States economy close to $60 billion a year. Therefore, there is a need to develop software testing techniques that are time and cost effective. Fully testing software under all possible combinations of parameters values cannot be reduced. However, testing can focus on covering all combinations of subsets of parameters and empirical data shows that doing so …

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Constrained Control And Optimization Of Tubular Solid Oxide Fuel Cells For Extending Cell Lifetime, Ben Spivey, John Hedengren, Thomas F. Edgar Jul 2012

Constrained Control And Optimization Of Tubular Solid Oxide Fuel Cells For Extending Cell Lifetime, Ben Spivey, John Hedengren, Thomas F. Edgar

Faculty Publications

Extending fuel cell lifetime is a necessary objective for reducing fuel cell power generation cost of electricity. Capital costs comprise the most significant fraction of the cost of electricity. Reducing the frequency of fuel cell replacement can be achieved by implementing a control strategy that prevents excursions into operating regions causing failure. In this paper we implement a constrained MIMO model predictive controller (MPC) to avoid the failure modes relevant for a high-temperature tubular solid oxide fuel cell (SOFC) system while performing load-following. The primary causes of failure are catalyst poisoning, fuel or air starvation, carbon deposition, and microcracking. Prior …

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Logistics Orchestration Modeling And Evaluation For Humanitarian Relief, Hoong Chuin Lau, Zhengping Li, Xin Du, Heng Jiang, Robert De Souza Jul 2012

Logistics Orchestration Modeling And Evaluation For Humanitarian Relief, Hoong Chuin Lau, Zhengping Li, Xin Du, Heng Jiang, Robert De Souza

Research Collection School Of Computing and Information Systems

This paper proposes an orchestration model for post-disaster response that is aimed at automating the coordination of scarce resources that minimizes the loss of human lives. In our setting, different teams are treated as agents and their activities are "orchestrated" to optimize rescue performance. Results from simulation are analysed to evaluate the performance of the optimization model.

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Identification Of Hemodynamically Optimal Coronary Stent Designs Based On Vessel Caliber, Timothy J. Gundert, Alison L. Marsden, Weiguang Yang, David S. Marks, John F. Ladisa Jul 2012

Identification Of Hemodynamically Optimal Coronary Stent Designs Based On Vessel Caliber, Timothy J. Gundert, Alison L. Marsden, Weiguang Yang, David S. Marks, John F. Ladisa

Biomedical Engineering Faculty Research and Publications

Coronary stent design influences local patterns of wall shear stress (WSS) that are associated with neointimal growth, restenosis, and the endothelialization of stent struts. The number of circumferentially repeating crowns NC for a given stent de- sign is often modified depending on the target vessel caliber, but the hemodynamic implications of altering NC have not previously been studied. In this investigation, we analyzed the relationship between vessel diameter and the hemodynamically optimal NC using a derivative-free optimization algorithm coupled with computational fluid dynamics. The algorithm computed the optimal vessel diameter, defined as minimizing the area of stent-induced …

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Advanced Intelligent Control And Optimization For Cardiac Pacemaker Systems, Wei Shi May 2012

Advanced Intelligent Control And Optimization For Cardiac Pacemaker Systems, Wei Shi

Dissertations

Since cardiovascular diseases are major causes of morbidity and mortality in the developed countries and the number one cause of death in the United States, their accurate diagnosis and effective treatment via advanced cardiac pacemaker systems have become very important. Intelligent control and optimization of the pacemakers are significant research subjects. Serious but infrequently occurring arrhythmias are difficult to diagnose. The use of electrocardiogram (ECG) waveform only cannot exactly distinguish between deadly abnormalities and temporary arrhythmias. Thus, this work develops a new method based on frequency entrainment to analyze pole-zero characteristics of the phase error between abnormal ECG and entrained …

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A New Metaheuristic Algorithm Motivated By The Rooting Phenomena In Plants, Behzad Nemati May 2012

A New Metaheuristic Algorithm Motivated By The Rooting Phenomena In Plants, Behzad Nemati

All Theses

In this thesis, we present a new metaheuristic algorithm for analyzing challenging optimization problems. Initial testing reveals the potential for the algorithm, which is based on the rooting phenomena found in plants in nature, to quickly produce effective solutions to challenging combinatorial optimization problems in the class NP. We present computational results describing the proposed metaheuristic's efficacy for an important class of scheduling problems and discuss areas of future work and application.

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Probabilistic Qos Analysis In Wireless Sensor Networks, Yunbo Wang May 2012

Probabilistic Qos Analysis In Wireless Sensor Networks, Yunbo Wang

School of Computing: Dissertations, Theses, and Student Research

Emerging applications of wireless sensor networks (WSNs) require real-time quality of service (QoS) guarantees to be provided by the network. Traditional analysis work only focuses on the first-order statistics, such as the mean and the variance of the QoS performance. However, due to unique characteristics of WSNs, a cross-layer probabilistic analysis of QoS performance is essential. In this dissertation, a comprehensive cross-layer probabilistic analysis framework is developed to investigate the probabilistic evaluation and optimization of QoS performance provided by WSNs. In this framework, the distributions of QoS performance metrics are derived, which are natural tools to discover the probabilities to …

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Design Of Meta-Materials Outside The Homogenization Limit Using Multiscale Analysis And Topology Optimization, Christopher Czech May 2012

Design Of Meta-Materials Outside The Homogenization Limit Using Multiscale Analysis And Topology Optimization, Christopher Czech

All Dissertations

The field of meta-materials engineering has largely expanded mechanical design possibilities over the last two decades; some notable design advances include the systematic engineering of negative Poisson's ratio materials and functionally graded materials, materials designed for optimal electronic and thermo-mechanical performances, and the design of materials under uncertainty. With these innovations, the systematic engineering of materials for design-specific uses is becoming more common in industrial and military uses. The motivation for this body of research is the design of the shear beam for a non-pneumatic wheel. Previously, a design optimization of a finite element model of the non-pneumatic wheel was …

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Generating Minimal Pair-Wise Covering Test Suites, Luis C. Gutierrez ^, Martine Ceberio * Apr 2012

Generating Minimal Pair-Wise Covering Test Suites, Luis C. Gutierrez ^, Martine Ceberio *

COURI Symposium Abstracts, Spring 2012

Software is ubiquitous and needs to be reliable. Software testing therefore plays an important role in software development. Proper testing a software system informs about its quality and reliability so as to prevent unexpected behavior during system execution. One of the methods to prevent failures consists in testing a system under different input values, but when all possible input values are tested, an impractical number of test cases might result. In software testing, pair-wise testing is a combinatorial technique which uses combination of pair input values to generate test cases. Using pair-wise testing dramatically reduces the number of test cases, …

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Optimizing Fermentation Medium To Produce Cyclosporin A Using Response Surface Methodology, Rofiq Sunaryanto Apr 2012

Optimizing Fermentation Medium To Produce Cyclosporin A Using Response Surface Methodology, Rofiq Sunaryanto

Makara Journal of Technology

Response surface methodology (RSM) is a three factorial model which illustrates the relationship between one or more independent variables. RSM can be used to optimize the fermentation medium for the production of Cyclosporin A from the isolate Tolypocladium inflatum. The optimal point of the response surface area is predicted by using a seconddegree polynomial model and applying the statistic model obtained from the central composite design (CCD). The results of optimizing the fermentation medium for Cyclopsorin using the three independent variables of glucose, casein, and KH2PO4 show that all three of the independent variables affect the production of Cyclosporin A. …

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A Three-Dimensional Inverse Finite Element Analysis Of The Heel Pad, Snehal Chokhandre, Jason P. Halloran, Antonie J. Van Den Bogert, Ahmet Erdemir Mar 2012

A Three-Dimensional Inverse Finite Element Analysis Of The Heel Pad, Snehal Chokhandre, Jason P. Halloran, Antonie J. Van Den Bogert, Ahmet Erdemir

Mechanical Engineering Faculty Publications

Quantification of plantar tissue behavior of the heel pad is essential in developing computational models for predictive analysis of preventive treatment options such as footwear for patients with diabetes. Simulation based studies in the past have generally adopted heel pad properties from the literature, in return using heel-specific geometry with material properties of a different heel. In exceptional cases, patient-specific material characterization was performed with simplified two-dimensional models, without further evaluation of a heel-specific response under different loading conditions. The aim of this study was to conduct an inverse finite element analysis of the heel in order to calculate heel-specific …

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A Study Of Queuing Theory In Low To High Rework Environments With Process Availability, Adam J. Brown Jan 2012

A Study Of Queuing Theory In Low To High Rework Environments With Process Availability, Adam J. Brown

Theses and Dissertations--Manufacturing Systems Engineering

In manufacturing systems subject to machine and operator resource constraints the effects of rework can be profound. High levels of rework burden the resources unnecessarily and as the utilization of these resources increases the expected queuing time of work in process increases exponentially. Queuing models can help managers to understand and control the effects of rework, but often this tool is overlooked in part because of concerns over accuracy in complex environments and/or the need for limiting assumptions. One aim of this work is to increase understanding of system variables on the accuracy of simple queuing models. A queuing model …

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A Fitness Function Elimination Theory For Blackbox Optimization And Problem Class Learning, Gautham Anil Jan 2012

A Fitness Function Elimination Theory For Blackbox Optimization And Problem Class Learning, Gautham Anil

Electronic Theses and Dissertations

The modern view of optimization is that optimization algorithms are not designed in a vacuum, but can make use of information regarding the broad class of objective functions from which a problem instance is drawn. Using this knowledge, we want to design optimization algorithms that execute quickly (efficiency), solve the objective function with minimal samples (performance), and are applicable over a wide range of problems (abstraction). However, we present a new theory for blackbox optimization from which, we conclude that of these three desired characteristics, only two can be maximized by any algorithm. We put forward an alternate view of …

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Economic Modeling & Optimization Of A Region Specific Multi-Feedstock Biorefinery Supply Chain, William H. Faulkner Jan 2012

Economic Modeling & Optimization Of A Region Specific Multi-Feedstock Biorefinery Supply Chain, William H. Faulkner

Theses and Dissertations--Manufacturing Systems Engineering

The objective of this thesis is to include strategic and tactical level decisions into the biorefinery supply chain design for a specific region while comparing multiple conversion technologies and biomass feedstocks. The allocation of biomass feedstocks, products, and the respective supply chain configuration locations are determined while ensuring the regions monthly biomass availability and product market demand constraints are met. This research considers all actions required to bring the bio-based products to market from harvesting, storing, and processing the biomass to market distribution. Two different conversion technologies are chosen for comparison: one advanced conversion technology and one conventional technology. Potential …

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Optimization In Energy And Power Management For Renewable-Diesel Microgrids Using Dynamic Programming Algorithm, Tu A. Nguyen, Mariesa L. Crow Jan 2012

Optimization In Energy And Power Management For Renewable-Diesel Microgrids Using Dynamic Programming Algorithm, Tu A. Nguyen, Mariesa L. Crow

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents an optimization analysis for energy and power management in microgrids with renewable energy resources and diesel generators. Dynamic Programming (DP) algorithm and the simplex method have been used to minimize the total daily cost of the system and also maximize the total efficiency of the energy storage system during charge and discharge. the algorithm is validated on a hybrid system for military forward operating base camps that contain a PV array, wind generator, hydrogen-Based fuel cell, batteries and diesel generators. © 2012 IEEE.

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Advanced Design Methodologies And Novel Applications Of Reflectarray Antennas, Payam Nayeri Jan 2012

Advanced Design Methodologies And Novel Applications Of Reflectarray Antennas, Payam Nayeri

Electronic Theses and Dissertations

Reflectarray antennas combine the numerous advantages of printed antenna arrays and reflector antennas and create a hybrid high-gain antenna with a low-profile, low-mass, and diversified radiation performance. Reflectarrays are now emerging as the new generation of high-gain antennas for long-distance communications. In this dissertation, some advanced concepts demonstrating novel features of reflectarray antennas are presented. • First, various approaches for radiation analysis of reflectarray antennas are described and implemented. Numerical results are then presented for a variety of systems and the advantages, limitations, and accuracy of these approaches are discussed and compared with each other. • A broadband technique by …

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Temperature And Strain Controlled Optimization Of Stabilization Of Polyacrylonitrile Precursor Fibers, Mark Parr Taylor Jan 2012

Temperature And Strain Controlled Optimization Of Stabilization Of Polyacrylonitrile Precursor Fibers, Mark Parr Taylor

Theses and Dissertations--Mechanical and Aerospace Engineering

Carbon fiber is one of the leading materials for high strength and modulus, and light weight applications. Improvements in carbon fiber properties are directly dependent on all aspects of manufacture, especially the process of stabilization. Therefore, it is the goal of this thesis to study the effects of the temperature and strain profile of the stabilization process, and the resulting carbon fiber tensile properties. In addition, the precursor fibers used were spun under two different draw ratios, to study the effects of the spinning parameters. Results indicated through DMA studies that completeness of stabilization reactions can be gauged by the …

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Networking And Security Solutions For Vanet Initial Deployment Stage, Baber Aslam Jan 2012

Networking And Security Solutions For Vanet Initial Deployment Stage, Baber Aslam

Electronic Theses and Dissertations

Vehicular ad hoc network (VANET) is a special case of mobile networks, where vehicles equipped with computing/communicating devices (called "smart vehicles") are the mobile wireless nodes. However, the movement pattern of these mobile wireless nodes is no more random, as in case of mobile networks, rather it is restricted to roads and streets. Vehicular networks have hybrid architecture; it is a combination of both infrastructure and infrastructure-less architectures. The direct vehicle to vehicle (V2V) communication is infrastructure-less or ad hoc in nature. Here the vehicles traveling within communication range of each other form an ad hoc network. On the other …

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Optimization Of Process Parameters For Faster Deposition Of Cuin1-Xgaxs2 And Cuin1-Xgaxse2-Ysy Thin Film Solar Cells, Ashwani Kaul Jan 2012

Optimization Of Process Parameters For Faster Deposition Of Cuin1-Xgaxs2 And Cuin1-Xgaxse2-Ysy Thin Film Solar Cells, Ashwani Kaul

Electronic Theses and Dissertations

Thin film solar cells have the potential to be an important contributor to the world energy demand in the 21st century. Among all the thin film technologies, CuInGaSe2 (CIGS) thin film solar cells have achieved the highest efficiency. However, the high price of photovoltaic (PV) modules has been a major factor impeding their growth for terrestrial applications. Reduction in cost of PV modules can be realized by several ways including choosing scalable processes amenable to large area deposition, reduction in the materials consumption of active layers, and attaining faster deposition rates suitable for in-line processing. Selenization-sulfurization of sputtered metallic Cu-In-Ga …

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New Mathematical And Evolutionary Optimization Methods To Achieve Fair Division In Multi-Agent Resource Allocation, Emmanuel Gurrola Molina Jan 2012

New Mathematical And Evolutionary Optimization Methods To Achieve Fair Division In Multi-Agent Resource Allocation, Emmanuel Gurrola Molina

Open Access Theses & Dissertations

The problem of resource allocation among a group of agents naturally arises in a wide range of real-life events. The subject has earned popularity across the disciplines of Economics, Computer Science, Artificial Intelligence Operations Research and Social Welfare. This resource allocation problem can be commonly referred to as Multi-Agent Resource Allocation (MARA). This work considers a MARA problem where a central agent decides to allocate a set of divisible and non-divisible goods. MARA is considered to be part of an interdisciplinary research area in which the literature is vast and rapidly developing. However, most of the available literature mainly focuses …

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Designing Optimal Aviation Baggage Screening Strategies Using The Monkey Search Algorithm, Edgar Ivan Jimenez Jan 2012

Designing Optimal Aviation Baggage Screening Strategies Using The Monkey Search Algorithm, Edgar Ivan Jimenez

Open Access Theses & Dissertations

This thesis addresses the aviation baggage screening design problem considering several baggage screening devices which may be used for system implementation, the devices have different false clear and false alarm rates, throughput and purchase costs. In the present research, a comprehensive cost function which not only includes the cost associated with purchase and operation of baggage security devices, but also includes the indirect costs associated with device errors is used. A new monkey search based evolutionary algorithm is presented to determine the best selection of baggage screening security devices in order to minimize the expected annual total cost. The final …

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Multi-Objective System Design Optimization Considering Environmental Emissions, Olivia Carolina Moreno Jan 2012

Multi-Objective System Design Optimization Considering Environmental Emissions, Olivia Carolina Moreno

Open Access Theses & Dissertations

The well-known reliability optimization problem, the redundancy allocation problem (RAP) involves the simultaneous selection of system components and a design level configuration that can meet several design constraints in order to optimize the predefined objective function(s). The RAP has been predominantly solved as a single objective optimization problem with the reliability of the system to be maximized or system design cost to be minimized. When considered as a multiple objective reliability optimization problem, the system reliability is maximized and the cost and weight of the system are minimized. In this work, the RAP was formulated as a multiple objective optimization …

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Implementation Of Evolutionary Algorithms On The Power Industry And Aviation Security, Anuar Jesus Aguirre Jan 2012

Implementation Of Evolutionary Algorithms On The Power Industry And Aviation Security, Anuar Jesus Aguirre

Open Access Theses & Dissertations

The main objective of the power electric power grid is to supply reliable electricity to all the customers. Customers could be industrial, commercial, household, transportation and others. The power grid is a complex and large, and it formed by the conjunction of the generation, transmission and distribution system. The present research is focused in power distribution system. A new component replacement analysis method to solve component replacement problems for complex electricity distribution systems using Genetic Algorithms is developed. In the present model a Taylor series expansion is used to approximate the associated opportunity cost for each component in the system. …

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An Optimization Approach To Indoor Location Problem Based On Received Signal Strength, Lei Zheng Jan 2012

An Optimization Approach To Indoor Location Problem Based On Received Signal Strength, Lei Zheng

Browse all Theses and Dissertations

This research was motivated by the desire of a Fortune 100 retail company to track its customers' behaviors through the implementation of a low-cost indoor location system using received signal devices. Indoor location through received signal strength (RSS) is of low costs, yet it suffers from poor accuracy due to lack of direct line-of-sight, multi-path ratio propagation, and various interferences. To improve its location estimation accuracy, therefore, we propose a mathematical programming based propagation approach for RSS based location systems. The core of our approach is an optimization model that minimizes the sum of squared errors of signal strength. In …

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