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Optimization

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Articles 151 - 180 of 198

Full-Text Articles in Operations Research, Systems Engineering and Industrial Engineering

Mathematical Modeling For Platform-Based Product Configuration Considering Total Life-Cycle Sustainability, Tian Lan Jan 2015

Mathematical Modeling For Platform-Based Product Configuration Considering Total Life-Cycle Sustainability, Tian Lan

Theses and Dissertations--Mechanical and Aerospace Engineering

Many companies are using platform-based product designs to fulfill the requirements of customers while maintaining low cost. However, research that integrates sustainability into platform-based product design is still limited. Considering sustainability during platform-based design process is a challenge because the total life-cycle from pre-manufacturing, manufacturing and use to post-use stages as well as economic, environmental and societal performance in these stages must be considered. In this research, an approach for quantifying sustainability is introduced and a mathematical model is developed for identifying a more sustainable platform. Data from life-cycle assessment is used to quantify environmental factors; criteria from the Product …


A Framework And System For A Multi-Model Decision Aid For Sustainable Farming Practices, Kasi Bharath Vegesana Jan 2015

A Framework And System For A Multi-Model Decision Aid For Sustainable Farming Practices, Kasi Bharath Vegesana

Computational Modeling & Simulation Engineering Theses & Dissertations

Decision support systems (DSS) for farmers address the need for modeling multiple processes and scenarios that affect farmer decision making. Existing DSS have various drawbacks that stop them from being deployed as decision support tools. This research proposes a multi-model simulation framework that can be used to analyze farm management practices at the crop level, individual farm level and at the community level to show the impact and alternatives for smallholder farming practices. A generic crop growth model is proposed, based on existing equations. We run sensitivity analysis on the model to identify important variables. The outputs from the crop …


Truckload Shipment Planning And Procurement, Neo Nguyen Dec 2014

Truckload Shipment Planning And Procurement, Neo Nguyen

Graduate Theses and Dissertations

This dissertation presents three issues encountered by a shipper in the context of truckload transportation. In all of the studies, we utilize optimization techniques to model and solve the problems. Each study is inspired from the real world and much of the data used in the experiments is real data or representative of real data.

The first topic is about the freight consolidation in truckload transportation. We integrate it with a purchase incentive program to increase truckload utilization and maximize profit. The second topic is about supporting decision making collaboration among departments of a manufacturer. It is a bi-objective optimization …


Reducing Carbon Emission Of Ocean Shipments By Optimizing Container Size Selection, Edwin Lik Ming Chong, Nang Laik Ma, Kar Way Tan Aug 2014

Reducing Carbon Emission Of Ocean Shipments By Optimizing Container Size Selection, Edwin Lik Ming Chong, Nang Laik Ma, Kar Way Tan

Research Collection School Of Computing and Information Systems

Human’s impact on earth through global warming is more or less an accepted fact. Ocean freight is estimated to contribute 4-5% of global carbon emissions and manufacturing companies can aid in reducing this amount. Many companies that ship goods through full container loads do not have the capabilities to ensure the containers they are using minimizes their carbon footprint. One of the reasons is the choice of non-ideal container sizes for their shipments. This paper provides a mathematical model to minimize companies’ shipping carbon footprints by selecting the ideal container sizes appropriate for their shipment volumes. Using data from a …


Strategies To Improve The Efficiency Of Emergency Medical Service (Ems) Systems Under More Realistic Conditions, Kanchala Sudtachat May 2014

Strategies To Improve The Efficiency Of Emergency Medical Service (Ems) Systems Under More Realistic Conditions, Kanchala Sudtachat

All Dissertations

Emergency medical service (EMS) systems provide medical care to pre-hospital patients who need rapid response and transportation. This dissertation proposes a new realistic approach for EMS systems in two major focuses: multiple unit dispatching and relocation strategies. This work makes recommendations for multiple-unit dispatch to multiple call priorities based on simulation optimization and heuristics. The objective is to maximize the expected survival rate. Simulation models are proposed to determine the optimization. A heuristic algorithm is developed for large-scale problems. Numerical results show that dispatching while considering call priorities, rather than always dispatching the closest medical units, could improve the effectiveness …


Poisson Distributed Individuals Control Charts With Optimal Limits, Negin Enayaty Ahangar May 2014

Poisson Distributed Individuals Control Charts With Optimal Limits, Negin Enayaty Ahangar

Graduate Theses and Dissertations

The conventional method used in attribute control charts is the Shewhart three sigma limits. The implicit assumption of the Normal distribution in this approach is not appropriate for skewed distributions such as Poisson, Geometric and Negative Binomial. Normal approximations perform poorly in the tail area of the these distributions. In this research, a type of attribute control chart is introduced to monitor the processes that provide count data. The economic objective of this chart is to minimize the cost of its errors which is determined by the designer. This objective is a linear function of type I and II errors. …


A Heuristic Algorithm For Determining The Part Set In A Powder-Bed Additive Manufacturing Machine., Sonja Dieder May 2014

A Heuristic Algorithm For Determining The Part Set In A Powder-Bed Additive Manufacturing Machine., Sonja Dieder

Electronic Theses and Dissertations

The goal of this research is to develop a procedure for the placement of a priority part into a planned build in a powder-bed additive manufacturing machine. Toward that goal, a heuristic procedure was developed that seeks to maximize the revenue in a scheduled build, subject to due-date constraints; i.e., all parts with the closest due date will not only be included in the build, but will be placed near the bottom of the build. Likewise, any part in the scheduled build that does not have an immediate due date is a candidate for removal in order to accommodate a …


Modeling Preventive Maintenance In Complex Systems, Jessica Rivas Apr 2014

Modeling Preventive Maintenance In Complex Systems, Jessica Rivas

Open Access Theses

This thesis presents an explicit consideration of the impacts of modeling decisions on the resulting maintenance planning. Incomplete data is common in maintenance planning, but is rarely considered explicitly. Robust optimization aims to minimize the impact of uncertainty--here, in contrast, I show how its impact can be explicitly quantified. Doing so allows decision makers to determine whether it is worthwhile to invest in reducing uncertainty about the system or the effect of maintenance. The thesis consists of two parts. Part I uses a case study to show how incomplete data arises and how the data can be used to derive …


Scheduling And Resource Allocation In Wireless Sensor Networks, Yosef Alayev Feb 2014

Scheduling And Resource Allocation In Wireless Sensor Networks, Yosef Alayev

Dissertations, Theses, and Capstone Projects

In computer science and telecommunications, wireless sensor networks are an active research area. Each sensor in a wireless sensor network has some pre-defined or on demand tasks such as collecting or disseminating data. Network resources, such as broadcast channels, number of sensors, power, battery life, etc., are limited. Hence, a schedule is required to optimally allocate network resources so as to maximize some profit or minimize some cost. This thesis focuses on scheduling problems in the wireless sensor networks environment. In particular, we study three scheduling problems in the wireless sensor networks: broadcast scheduling, sensor scheduling for area monitoring, and …


Performance Analysis And Scheduling Strategies For Ambulatory Surgical Facilities, Xuanqi Zhang Jan 2014

Performance Analysis And Scheduling Strategies For Ambulatory Surgical Facilities, Xuanqi Zhang

Dissertations

Ambulatory surgery is a procedure that does not require an overnight hospital stay and is cost effective and efficient. The goal of this research is to develop an ASF operational model which allows management to make key decisions. This research develops and utilizes the simulation software ARENA based model to accommodate: (a) Time related uncertainties – Three system uncertainties characterize the problem (ii) Surgery time variance (ii) Physician arrival delay and (iii) Patient arrival delay; (b) Resource Capture Complexities – Patient flows vary significantly and capture/utilize both staffing and/or physical resources at different points and varying levels; and (c) Processing …


Fuzzy Optimization Of Acknowledged System Of Systems Meta-Architectures For Agent Based Modeling Of Development, Louis Pape, Siddhartha Agarwal, Kristin Giammarco, Cihan Dagli Jan 2014

Fuzzy Optimization Of Acknowledged System Of Systems Meta-Architectures For Agent Based Modeling Of Development, Louis Pape, Siddhartha Agarwal, Kristin Giammarco, Cihan Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

Acknowledged systems of systems (SoS) lie on a continuum between authoritarian central control and anarchy. The constituent systems are independent, with a life and purpose of their own. The systems require not only technical interfaces, but also social interactions, to create the SoS. A fuzzy optimization process may be used to select a desirable SoS configuration, but it may be unachievable due to the inability to persuade the systems to cooperate in the plan. Modeling the systems' internal decision processes could help understand how to design better SoS architectures. This research used generic, modular modeling processes to examine two proposed …


Hosx: Hospital Operations Excellence Model, Shivon S. Boodhoo May 2013

Hosx: Hospital Operations Excellence Model, Shivon S. Boodhoo

Dissertations

Hospital performance can be evaluated in four categories: (i) quality of care, (ii) process of care (iii) financial and (iv) operations productivity. Of these, ‘quality of care’ is the most widely reported and studied measure of performance, and focuses primarily on the clinical outcomes of the patient. In contrast, operations productivity and efficiency is the least studied measure, and currently there is limited ability to evaluate how efficiently the hospital has used its resources to deliver healthcare services. Cost containment in the healthcare industry is a challenging problem, and there is a lack of models and methods to benchmark hospital …


Master Physician Scheduling Problem, Aldy Gunawan, Hoong Chuin Lau May 2013

Master Physician Scheduling Problem, Aldy Gunawan, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

We study a real-world problem arising from the operations of a hospital service provider, which we term the master physician scheduling problem. It is a planning problem of assigning physicians’ full range of day-to-day duties (including surgery, clinics, scopes, calls, administration) to the defined time slots/shifts over a time horizon, incorporating a large number of constraints and complex physician preferences. The goals are to satisfy as many physicians’ preferences and duty requirements as possible while ensuring optimum usage of available resources. We propose mathematical programming models that represent different variants of this problem. The models were tested on a real …


Exact And Representative Algorithms For Multi Objective Optimization, Ozgu Turgut Jan 2013

Exact And Representative Algorithms For Multi Objective Optimization, Ozgu Turgut

Wayne State University Dissertations

In most real-life problems, the decision alternatives are evaluated with multiple conflicting criteria. The entire set of non-dominated solutions for practical problems is impossible to obtain with reasonable computational effort. Decision maker generally needs only a representative set of solutions from the actual Pareto front. First algorithm we present is for efficiently generating a well dispersed non-dominated solution set representative of the Pareto front which can be used for general multi objective optimization problem. The algorithm first partitions the criteria space into grids to generate reference points and then searches for non-dominated solutions in each grid. This grid-based search utilizes …


Optimization Of Strategic Planning Processes For Configurable Products: Considerations For Global Supply, Demand, And Sustainability Issues, Edward Lawrence Umpfenbach Jan 2013

Optimization Of Strategic Planning Processes For Configurable Products: Considerations For Global Supply, Demand, And Sustainability Issues, Edward Lawrence Umpfenbach

Wayne State University Dissertations

The assortment planning problem is to decide on the set of products that a retailer or manufacturer will offer to its customers to maximize profitability. While assortment planning research has been expanding in recent years, the current models are inadequate for the needs of a configurable product manufacturer. In particular, we address assortment planning for an automobile manufacturer. We develop models to integrate assortment planning and supply chain management, designed for use by a large automaker in its strategic planning phase. Our model utilizes a multinomial logit model transformed into a mixed integer linear program through the Charnes-Cooper transformation. It …


A Mechanism Design Approach To Bandwidth Allocation In Tactical Data Networks, Ankur Mour Jan 2013

A Mechanism Design Approach To Bandwidth Allocation In Tactical Data Networks, Ankur Mour

Open Access Theses

The defense sector is undergoing a phase of rapid technological advancement, in the pursuit of its goal of information superiority. This goal depends on a large network of complex interconnected systems - sensors, weapons, soldiers - linked through a maze of heterogeneous networks. The sheer scale and size of these networks prompt behaviors that go beyond conglomerations of systems or `system-of-systems'. The lack of a central locus and disjointed, competing interests among large clusters of systems makes this characteristic of an Ultra Large Scale (ULS) system. These traits of ULS systems challenge and undermine the fundamental assumptions of today's software …


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 …


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 …


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.


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.


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, …


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 …


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 …


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 …


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 …


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. …


Planned Tournament Selection, Douglas Mccorkle, Daniel Ashlock, Steven Corns, Kenneth Mark Bryden Sep 2011

Planned Tournament Selection, Douglas Mccorkle, Daniel Ashlock, Steven Corns, Kenneth Mark Bryden

Engineering Management and Systems Engineering Faculty Research & Creative Works

Tournament selection is a versatile method of selection and replacement used in evolutionary computation. Normally tournaments are chosen uniformly at random. This study demonstrates the effectiveness of planning tournaments in advance to control information flow within a population being evolved for optimization. Tests are performed on a variety of evolutionary test problems, finding that different planned tournament schemes yield significant differences in performance. the correct type of planned tournament is found to be problem dependent. in addition to a linear-function scheme for planning tournaments, this study also introduces a technique called multi-deme planned tournaments selection which permits simpler cases of …


A Study On Facility Planning Using Discrete Event Simulation: Case Study Of A Grain Delivery Terminal, Sarah M. Asio Jul 2011

A Study On Facility Planning Using Discrete Event Simulation: Case Study Of A Grain Delivery Terminal, Sarah M. Asio

Department of Industrial and Management Systems Engineering: Dissertations, Theses, and Student Research

The application of traditional approaches to the design of efficient facilities can be tedious and time consuming when uncertainty and a number of constraints exist. Queuing models and mathematical programming techniques are not able to capture the complex interaction between resources, the environment and space constraints for dynamic stochastic processes. In the following study discrete event simulation is applied to the facility planning process for a grain delivery terminal. The discrete event simulation approach has been applied to studies such as capacity planning and facility layout for a gasoline station and evaluating the resource requirements for a manufacturing facility. To …


A Method To Improve The Sustainment Of Systems Based On Probability And Consequences, Michael Ashton Gaintner Apr 2011

A Method To Improve The Sustainment Of Systems Based On Probability And Consequences, Michael Ashton Gaintner

Engineering Management & Systems Engineering Theses & Dissertations

The FROST Method is presented which improves the efficiency of long-term sustainment of hardware systems. The FROST Method makes sustainment and scheduling decisions based on the minimization of the expected value of current and future costs. This differs from current methods which tend to base decisions not on the expected value of costs, but on the expected inventory demand found through projections using data which is often inaccurate.

Distributions are used to account for randomness and inaccuracy in inputs such as failure rates and vendor-claimed dates for end of production. A Monte Carlo technique is then used to convert these …


Optimization Of Screw Cap Process For E & J Gallo Winery, Robert Trent Latimer Mar 2011

Optimization Of Screw Cap Process For E & J Gallo Winery, Robert Trent Latimer

Industrial and Manufacturing Engineering

This project takes a microscopic look at all raw material, machinery, and practices that effect the screw cap process of wine products in order to highlight and eliminate the causes of defects. The approach for this project involves the analysis of process capability for raw material to achieve its required dimensions. This project also displays methods of attaining appropriate machinery settings, and provides a basis for operating standards. Many quality engineering applications are used throughout this study, revealing the decision process for analyzing said applications.

The studies in this project found uncontrolled dimensions in the suppliers’ caps and bottles and …