Operations Research, Systems Engineering and Industrial Engineering Commons^™

Tight Polyhedral Representations Of Discrete Sets Using Projections, Simplices, And Base-2 Expansions, Stephen Henry

All Dissertations

This research effort focuses on the acquisition of polyhedral outer-approximations to the convex hull of feasible solutions for mixed-integer linear and mixed-integer nonlinear programs. The goal is to produce desirable formulations that have superior size and/or relaxation strength. These two qualities often have great influence on the success of underlying solution strategies, and so it is with these qualities in mind that the work of this dissertation presents three distinct contributions.
The first studies a family of relatively unknown polytopes that enable the linearization of polynomial expressions involving two discrete variables. Projections of higher-dimensional convex hulls are employed to reduce …

In-Wheel Coupled Suspenison And Drive System For Attitude Control And Vehicle Propulsion, Robert Clippard

All Dissertations

The automotive marketplace is a volatile and dynamic system driven by consumer desires, marketing, fuel prices, technology, and legislation. Recently many of these factors have culminated in a common effort to encourage hybrid and electric vehicle development. The technology for electric vehicles has finally found enough maturity to be implemented into consumer based vehicles from hybrid SUVs to high performance sports cars. This expansion in available propulsion systems and vehicle architectures has spurred research and development into new and novel approaches for propulsion as well as systems to provide increased ride comfort.
This work presents a dual electric motor drive …

Decentralized Decision Support For An Agent Population In Dynamic And Uncertain Domains, Pradeep Reddy Varakantham, Shih-Fen Cheng, Thi Duong Nguyen

Research Collection School Of Computing and Information Systems

This research is motivated by problems in urban transportation and labor mobility, where the agent flow is dynamic, non-deterministic and on a large scale. In such domains, even though the individual agents do not have an identity of their own and do not explicitly impact other agents, they have implicit interactions with other agents. While there has been much research in handling such implicit effects, it has primarily assumed controlled movements of agents in static environments. We address the issue of decision support for individual agents having involuntary movements in dynamic environments . For instance, in a taxi fleet serving …

Message-Passing Algorithms For Large Structured Decentralized Pomdps, Akshat Kumar, Shlomo Zilberstein

Research Collection School Of Computing and Information Systems

Decentralized POMDPs provide a rigorous framework for multi-agent decision-theoretic planning. However, their high complexity has limited scalability. In this work, we present a promising new class of algorithms based on probabilistic inference for infinite-horizon ND-POMDPs---a restricted Dec-POMDP model. We first transform the policy optimization problem to that of likelihood maximization in a mixture of dynamic Bayes nets (DBNs). We then develop the Expectation-Maximization (EM) algorithm for maximizing the likelihood in this representation. The EM algorithm for ND-POMDPs lends itself naturally to a simple message-passing paradigm guided by the agent interaction graph. It is thus highly scalable w.r.t. the number of …

Distributed Model Shaping For Scaling To Decentralized Pomdps With Hundreds Of Agents, Prasanna Velagapudi, Pradeep Reddy Varakantham, Katia Sycara, Paul Scerri

Research Collection School Of Computing and Information Systems

The use of distributed POMDPs for cooperative teams has been severely limited by the incredibly large joint policy- space that results from combining the policy-spaces of the individual agents. However, much of the computational cost of exploring the entire joint policy space can be avoided by observing that in many domains important interactions between agents occur in a relatively small set of scenarios, previously defined as coordination locales (CLs) [11]. Moreover, even when numerous interactions might occur, given a set of individual policies there are relatively few actual interactions. Exploiting this observation and building on an existing model shaping algorithm, …

Incremental Dcop Search Algorithms For Solving Dynamic Dcop Problems, William Yeoh, Pradeep Varakantham, Xiaoxun Sun, Sven Koenig

Research Collection School Of Computing and Information Systems

Distributed constraint optimization problems (DCOPs) are well-suited for modeling multi-agent coordination problems. However, most research has focused on developing algorithms for solving static DCOPs. In this paper, we model dynamic DCOPs as sequences of (static) DCOPs with changes from one DCOP to the next one in the sequence. We introduce the ReuseBounds procedure, which can be used by any-space ADOPT and any-space BnB-ADOPT to find cost-minimal solutions for all DCOPs in the sequence faster than by solving each DCOP individually. This procedure allows those agents that are guaranteed to remain unaffected by a change to reuse their lower and upper …

Effect Of Gold Content On The Reliability Of Snagcu Solder Joints, Jianbiao Pan, Julie Silk, Mike Powers, Patrick Hyland

Industrial and Manufacturing Engineering

Electroplated Ni/Au over Cu is a popular metallization for PCB finish as well as for component leads, especially wire-bondable high frequency packages, where the gold thickness requirement for wirebonding is high. The general understanding is that less than 3 wt% of Au is acceptable in SnPb solder joints. However, little is known about the effect of Au content on the reliability of SnAgCu solder joints. The purpose of this study is to determine the acceptable level of Au in SAC305 solder joints. Three different package platforms with different Au thicknesses were assembled on boards with two different Au thicknesses using …

Grain Refinement Vs. Crystallographic Texture: Mechanical Anisotropy In A Magnesium Alloy, D. C. Foley, M. Al-Maharbi, K. T. Hartwig, I. Karaman, L. J. Kecskes, S. N. Mathaudhu

United States Army: Publications

A magnesium alloy was subjected to severe plastic deformation via an unconventional equal channel angular extrusion route at decreasing temperatures. This method facilitates incremental grain refinement and enhances formability by activating dynamic recrystallization in the initial steps and suppressing deformation twinning. Compression experiments in three orthogonal directions demonstrated high strength levels in the processed sample, up to 350 MPa in yield and 500 MPa in ultimate strengths. Notable flow stress anisotropy is correlated with the processing texture and microstructure.

Acuta Enews April 2011 Vol. 40, No. 4

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Partial Budgeting Analysis Of Conventional Pump Over Versus Pulsair Cap Management System For A Large–Scale California Winery, Zachary Thomas Hicks

Agribusiness

The purpose of this project was to evaluate the financial feasibility of implementing an automated gas injection system from Pulsair as an alternative to the traditional pump over cap mixing technique that is used during the alcoholic fermentation stage of winemaking.

There were various costs involved in this project that were determined and explained through the use of the partial budgeting method. The costs that were thoroughly analyzed included equipment, labor, utility, and initial investment costs for the Pulsair system as well as the related pump over operation costs. After the two methods associated numbers were evaluated, they were then …

Design And Implementation Of An Automated Pick And Place System For Johanson Technology, Inc., Alex M. Felker

Industrial and Manufacturing Engineering

Johanson Technology, a capacitor and microelectronic part manufacturer, located in Camarillo, CA has forecasted a 50% increase in demand for single layer capacitors for the year 2011. Johanson chose to hire an intern to design and implement a robotic pick and place system to meet this demand. A complete automated system composed of a Stäubli RS20 robotic arm, CS8C-M Controller, and Electrosort Bowl Feeder needed to be integrated into an environment where no system currently existed. A bill of materials and parts list indicated that the entire system would be a fixed cost of $50,104. This proved to be the …

Process Improvement Of Kaiser Permanente Medical Group, Connie Chou, Brett Witherall

Industrial and Manufacturing Engineering

This report seeks to improve the operations of the Kaiser Permanente’s Central Refill Pharmacy. In particular, the need for better workstations became evident when witnessing the cluttered appearance of the packing workbenches in the facility. Furthermore, one of Kaiser’s largest problem areas is the physical strain caused by the repetitive motion required of the packing job function. A redesign of the packing workstations has been developed on Microsoft Visio in order to reduce clutter, be more space efficient, and decrease eye and arm movement associated with employee strain. The most significant additions are an automated slide that transfers packages from …

Random Keys Genetic Algorithms Scheduling And Rescheduling Systems For Common Production Systems, Elkin Rodriguez-Velasquez

Engineering Management & Systems Engineering Theses & Dissertations

The majority of scheduling research deals with problems in specific production environments with specific objective functions. However, in many cases, more than one problem type and/or objective function exists, resulting in the need for a more generic and flexible system to generate schedules. Furthermore, most of the published scheduling research focuses on creating an optimal or near optimal initial schedule during the planning phase. However, after production processes start, circumstances like machine breakdowns, urgent jobs, and other unplanned events may render the schedule suboptimal, obsolete or even infeasible resulting in a "rescheduling" problem, which is typically also addressed for a …

A Structured Project-Risk Management And Life Cycle Framework For Complex Systems: Ship Repair And Maintenance (Sr&M) Projects, Michael Craig Plumb

Engineering Management & Systems Engineering Theses & Dissertations

This dissertation contributes to insights regarding the implications of using Project Risk Management (PRM) and Life Cycle Assessment (LCA) in managing projects for a complex system. The PRM approach apprehends many forms of risk both internal and external within a given project and assists the manager in determining the level of importance of each individual project phase and component to optimize project success. The life cycle approach to project management is used with short-term limitations with respect to a product's life cycle over several years. The literature discusses many tools and techniques that assist project managers in implementing optimal solutions, …

Evaluation System Design And Academic Performance Analysis Using Clustering And Simulation, Volkan Cakir

Engineering Management & Systems Engineering Theses & Dissertations

The starting point of this study was to understand the possible causes of evaluation system change in a military academic environment. With that motivation the objectives of this study were defined as examining student profiles in a military academy, establishing the nature of academic performance, comparing student groups that were identified by course scores, analyzing student performance changes over time and developing a manageable evaluation system and curriculum by comparing different scenarios.

An analysis was performed on the literature on academic performance prediction, cluster analysis methodologies and their development, and specifically summarized cluster analytic academic performance studies where these two …

Exploring The Effects Of Cooperative Adaptive Cruise Control In Mitigating Traffic Congestion, Georges M. Arnaout

Engineering Management & Systems Engineering Theses & Dissertations

The aim of this research is to examine the impact of CACC (Cooperative Adaptive Cruise Control) equipped vehicles on traffic-flow characteristics of a multilane highway system. The research identifies how CACC vehicles affect the dynamics of traffic flow on a road network and demonstrates the potential benefits of reducing traffic congestion due to stop-and-go traffic conditions. An agent-based traffic simulation model is developed specifically to examine the effect of these intelligent vehicles on the traffic flow dynamics. Traffic performance metrics characterizing the evolution of traffic congestion throughout the road network, are analyzed. Different CACC penetration levels are studied.

The positive …

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 Models And Approximate Algorithms For The Aerial Refueling Scheduling And Rescheduling Problems, Sezgin Kaplan

Engineering Management & Systems Engineering Theses & Dissertations

The Aerial Refueling Scheduling Problem (ARSP) can be defined as determining the refueling completion times for fighter aircrafts (jobs) on multiple tankers (machines) to minimize the total weighted tardiness. ARSP can be modeled as a parallel machine scheduling with release times and due date-to-deadline window. ARSP assumes that the jobs have different release times, due dates, and due date-to-deadline windows between the refueling due date and a deadline to return without refueling. The Aerial Refueling Rescheduling Problem (ARRP), on the other hand, can be defined as updating the existing AR schedule after being disrupted by job related events including the …

Towards An Organizational Strategic Vitality Theory: A Study Of A Public Sector Board Of Directors, Keith L. Woodman

Engineering Management & Systems Engineering Theses & Dissertations

Boards of directors govern practically all organizations of significant size in the public and private sector. Improving the understanding of how boards function is critical because when boards fail, the results can be devastating. Little is understood about the functioning of boards of directors in the public sector, which accounts for a significant amount of the gross national product of the world's economy. The author observed a public sector board of directors for one year. Using the grounded theory research method to analyze the observations, he generated a theory of organizational strategic vitality that describes how a board of directors …

A Hybrid Lehmer Code Genetic Algorithm And Its Application On Traveling Salesman Problems, Jun Zhang

Engineering Management & Systems Engineering Theses & Dissertations

Traveling Salesman Problems (TSP) is a widely studied combinatorial optimization problem. The goal of the TSP is to find a tour which begins in a specific city, visits each of the remaining cities once and returns to the initial cities such that the objective functions are optimized, typically involving minimizing functions like total distance traveled, total time used or total cost.

Genetic algorithms were first proposed by John Holland (1975). It uses an iterative procedure to find the optimal solutions to optimization problems.

This research proposed a hybrid Lehmer code Genetic Algorithm. To compensate for the weaknesses of traditional genetic …