Digital Commons Network^™

Phased Helical Antenna Array For Cubesat Application, Kameron Lacalli

Undergraduate Honors Theses

CubeSats communication links are typically slow due to their power and size restrictions. However, a low power, high speed down link connection can allow for greater data collection and relaying, pushing the capability of 1U CubeSats beyond what is traditionally thought possible. Investigated here is the feasibility of a 11 Mb/s down link connection on a 1U CubeSat, accomplished via 2x2 helical antenna phased array operating on the 802.11 standard. Using a phased array also allows for beam steering to secure connection with the ground station when the on board ADCS may not provide precise pointing capability of the CubeSat, …

Process Development For High Powered Amplifier Au/Sn Eutectic Die Attach Via Vacuum Furnace, Zachary F. Blanden

Graduate Dissertations and Theses

This research was conducted to develop and qualify a vacuum GaAs semiconductor monolithic microwave integrated circuit die attach process. Research was done to understand the causes and effects of voiding levels on device performance and reliability. Simultaneous investigation was done to qualify vacuum-attach as a successful methodology by which minimal voiding levels were achieved. After an initial vacuum-attach trial was completed to verify the methodology, internal accept/reject criteria were developed to qualify die attach interfaces. A dual phase attachment methodology was created to minimize tolerance stacking resulting in more consistent component placement. MATLAB image processing code was developed to quantify …

Energy-Climate-Manufacturing Nexus: New Insights From The Regional And Global Supply Chains Of Manufacturing Industries, Murat Kucukvar, Bunyamin Canseva, Gokhan Egilmez, Nuri C. Onat, Hamidreza Samadi

Mechanical and Industrial Engineering Faculty Publications

The main objectives of this research are to improve our understanding of energy-climate-manufacturing nexus within the context of regional and global manufacturing supply chains as well as show the significance of full coverage of entire supply chain tiers in order to prevent significant underestimations, which might lead to invalid policy conclusions. With this motivation, a multi region input–output (MRIO) sustainability assessment model is developed by using the World Input–Output Database, which is a dynamic MRIO framework on the world’s 40 largest economies covering 1440 economic sectors. The method presented in this study is the first environmentally-extended MRIO model that harmonizes …

Constrained Multi-Group Project Allocation Using Mahalanobis Distance, Abdulaziz Saud Alkabaa

Doctoral Dissertations

Optimal allocation is one of the most active research areas in operation research using binary integer variables. The allocation of multi constrained projects among several options available along a given planning horizon is an especially significant problem in the general area of item classification. The main goal of this dissertation is to develop an analytical approach for selecting projects that would be most attractive from an economic point of view to be developed or allocated among several options, such as in-house engineers and private contractors (in transportation projects). A relevant limiting resource in addition to the availability of funds is …

Integrating The Cost Of Quality Into Multi-Products Multi-Components Supply Chain Network Design, Waleed Abdussalam Gueir

Doctoral Dissertations

More than ever before the success of a company heavily depends on its supply chain and how efficient the network. A supply chain needs to be configured in such a manner as to minimize cost while still maintaining a good quality level to satisfy the end user and to be efficient, designing for the network and the whole chain is important. Including the cost of quality into the process of designing the network can be rewording and revealing. In this research the concept of cost of quality as a performance measure was integrated into the supply chain network designing process …

Time Series Classification Using Covariance Descriptors, Oluwaseun Winsala

Theses and Dissertations

This thesis presents a novel framework for time series classification that leverages the geometric structure of covariance matrices when labeling signals. Our method maps each signal to a new multivariate localized feature signal (MLFS) representation, from which we compute a covariance descriptor. This robust MLFS covarieance representation handles classification tasks where the sampling rates of the signals vary within a class or classes. We demonstrate that by simply using the k-nearest neighbor classification rule and multiclass kernel support vector machine with the Riemannian metric between the MLFS convariance matrices, which produces state-of-the-art results on a number of standard datasets. Moreover, …

Examination And Utilization Of Rare Features In Text Classification Of Injury Narratives, Hsin-Ying Huang

Open Access Dissertations

Thanks to the advances in computing and information technology, analyzing injury surveillance data with statistical machine learning methods has grown in popularity, complexity, and quality over recent years. During that same time, researchers have recognized the limitations of statistical text analysis with limited training data. In response to the two primary challenges for statistical text analysis, dimensionality reduction and sparse data, many studies have focused on improving machine learning algorithms. Less research has been done, though, to examine and improve statistical machine learning methods in text classification from a linguistic perspective.

This study addresses this research gap by examining the …

Impact Of Rfid Information-Sharing Coordination Over A Supply Chain With Reverse Logistics, Juan Jose Nativi Nicolau

Open Access Dissertations

Companies have adopted environmental practices such as reverse logistics over the past few decades. However, studies show that aligning partners inside the green supply chain can be a substantial problem. This lack of coordination can increase overall supply chain cost. Information technology such as Radio Frequency Identification (RFID) has the potential to enable decentralized supply chain coordinate their information. Even though there are research that address RFID on traditional supply chain, few researches address how to coordinate RFID information sharing in a green supply chain. We study, through simulation experiments, two types of RFID information-sharing coordination under different configurations related …

Adaptive Sampling Trust-Region Methods For Derivative-Based And Derivative-Free Simulation Optimization Problems, Sara Shashaani

Open Access Dissertations

We consider unconstrained optimization problems where only “stochastic” estimates of the objective function are observable as replicates from a Monte Carlo simulation oracle. In the first study we assume that the function gradients are directly observable through the Monte Carlo simulation. We propose ASTRO, which is an adaptive sampling based trust-region optimization method where a stochastic local model is constructed, optimized, and updated iteratively. ASTRO is a derivative-based algorithm and provides almost sure convergence to a first-order critical point with good practical performance. In the second study the Monte Carlo simulation is assumed to provide no direct observations of the …

Metrics Of Critical Pair Identification, Zixu Zhang

Open Access Theses

Critical Pair Identification works as a potential assistive tool for human air traffic controllers by identifying potentially dangerous situations that are not detected by proposed automated separation assurance systems. This concept specifically considers conflicts that might arise if aircraft unexpectedly deviate from their planned flight path in the near future. Five metrics of the critical pair concept, Critical Pair Count, Time to Risk Exposure, Lead Time, Risk Exposure Duration and Blunder Sensitivity Index, have been developed and mathematically defined to characterize the safety level of an aircraft pair or a volume of air space. Algorithm that computes proposed metrics is …

Comparing Three Instructional Modes For An Engineering Economy Course, Farnaz Ghazi Nezami, M. B. Yildirim, G. Grossi Crema

Industrial & Manufacturing Engineering Publications

This study compares three instructional modes in an “Engineering Economy” course: online, face-to-face (FtF), and flipped. Engineering Economy is a core course in this study and incorporates students with diverse backgrounds from different engineering majors. To discern the relation between student characteristics and teaching modality, an online questionnaire was designed for each mode and distributed over a two-year period. Data was collected and several statistical analyses were conducted to study the relationship between pedagogical delivery modes and various student-based factors such as gender, age, course load, living distance from campus, computer skills, work status, and first language. Students’ performance, persistence, …

Taming Tail Latency For Erasure-Coded, Distributed Storage Systems, Jingxian Fan

Open Access Theses

Nowadays, in distributed storage systems, long tails of responsible time are of particular concern. Modern large companies like Bing, Facebook and Amazon Web Service show that 99.9th percentile response times being orders of magnitude worse than the mean. With the advantages of maintaining high data reliability and ensur- ing enough space eciency, erasure code has become a popular storage method in distributed storage systems. However, due to the lack of mathematical models for analyzing erasure-coded based distributed storage systems, taming tail latency is still an open problem.

In this research, we quantify tail latency in such systems by deriving a …

An Agent-Based Approach To Human Migration Movement, Larry Lin, Kathleen M. Carley, Shih-Fen Cheng

Research Collection School Of Computing and Information Systems

How are the populations of the world likely to shift? Which countries will be impacted by sea-level rise? This paper uses a country-level agent-based dynamic network model to examine shifts in population given network relations among countries, which influences overall population change. Some of the networks considered include: alliance networks, shared language networks, economic influence networks, and proximity networks. Validation of model is done for migration probabilities between countries, as well as for country populations and distributions. The proposed framework provides a way to explore the interaction between climate change and policy factors at a global scale.

Orienteering Problem: A Survey Of Recent Variants, Solution Approaches And Applications, Aldy Gunawan, Hoong Chuin Lau, Pieter Vansteenwegen

Research Collection School Of Computing and Information Systems

The Orienteering Problem (OP) has received a lot of attention in the past few decades. The OP is a routing problem in which the goal is to determine a subset of nodes to visit, and in which order, so that the total collected score is maximized and a given time budget is not exceeded. A number of typical variants has been studied, such as the Team OP, the (Team) OP with Time Windows and the Time Dependent OP. Recently, a number of new variants of the OP was introduced, such as the Stochastic OP, the Generalized OP, the Arc OP, …

Predicting The Performance Of Queues: A Data Analytic Approach, Kum Khiong Yang, Cayirli Tugba, Mei Wan Low

Research Collection Lee Kong Chian School Of Business

Existing models of multi-server queues with system transience and non-standard assumptions are either too complex or restricted in their assumptions to be used broadly in practice. This paper proposes using data analytics, combining computer simulation to generate the data and an advanced non-linear regression technique called the Alternating Conditional Expectation (ACE) to construct a set of easy-to-use equations to predict the performance of queues with a scheduled start and end time. Our results show that the equations can accurately predict the queue performance as a function of the number of servers, mean arrival load, session length and service time variability. …

A Mixed Integer Linear Programming Approach For Developing Salary Administration Systems, Taner Cokyasar

Masters Theses

Determining salary increases of executive personnel is a challenging decision process for many companies. Salary administration policies that aid in the determination of salary increases and other compensation benefits have a wide variety of advantages for both a company and its employees. This thesis develops a mathematical programming approach to create a salary administration system that recognizes the importance of performance and potential of employees for future promotions as major components of a salary increase policy for executive personnel. A number of companies all over the world use salary administration systems that integrate work performance and potential for advancement to …

A Neural Network For Collaborative Forecasting, Abdulrahman M. Enani

Masters Theses

As the supply chain activities’ backbone, demand forecasting must be accurate. This paper proposes an artificial neural network forecasting model, which integrates and synchronizes shared information, such as sales or consumption rate among different partners, to improve the forecasting’s accuracy. This information sharing is part of the collaborative planning, forecasting and replenishment (CPFR) model, which is a supply chain model aiming to enhance the supply chain’s efficiency by jointly planning and forecasting between two or more supply chain partners that will be used as the base for production and replenishment activities. The model is validated using a tuna product sales …

Managing Egress Of Crowd During Infrastructure Disruption, Teck Hou Teng, Shih-Fen Cheng, Trong-Nghia Truong, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

In a large indoor environment such as a sports arena or convention center, smooth egress of crowd after an event can be seriously affected if infrastructure such as elevators and escalators break down. In this paper, we propose a novel crowd simulator known as SIM-DISRUPT for simulating egress scenarios in non-emergency situations. To surface the impact of disrupted infrastructure on the egress of crowd, SIM-DISRUPT includes features that allow users to specify selective disruptions as well as strategies for controlling the distribution and egress choices of crowd. Using SIM-DISRUPT, we investigate effects of crowd distribution, egress choices and infrastructure disruptions …

Traffic Simulation Model For Port Planning And Congestion Prevention, Baoxiang Li, Kar Way Tan, Trong Khiem Tran

Research Collection School Of Computing and Information Systems

Effective management of land-side transportation provides the competitive advantage to port terminal operators in improving services and efficient use of limited space in an urban port. We present a hybrid simulation model that combines traffic-flow modeling and discrete-event simulation for land-side port planning and evaluation of traffic conditions for a number of what-if scenarios. We design our model based on a real-world case of a bulk cargo port. The problem is interesting due to complexity of heterogeneous closed-looped internal vehicles and external vehicles traveling in spaces with very limited traffic regulation (no traffic lights, no traffic wardens) and the traffic …

A Fuzzy Inference System Approach For Evaluating The Feasibility Of Product Remanufacture, Thomas Aming'a. Omwando

Theses and Dissertations

In the recent past, efforts have been made in enhancing sustainable manufacturing aimed at protecting the environment and saving natural resources. Among the efforts that have been explored include strategies to ensure responsible end-of-life product management so as reduce the impact on the environment and achieve effective use of resources. Towards this end, reduce, reuse and recycle product disposal strategies have found a lot of consideration in manufacturing. Of the product reuse strategies, remanufacturing has been widely applied owing to its unique feature of rendering the remanufactured product as good as new. For remanufacturers, this strategy leads to provision of …

Development Of Instrumentation And Control Systems For An Integral Large Scale Pressurized Water Reactor, Matthew Rowland Morrow Lish

Doctoral Dissertations

Small and large scale integral light water reactors are being developed to supply electrical power and to meet the needs of process heat, primarily for water desalination. This dissertation research focuses on the instrumentation and control of a large integral inherently safe light water reactor (designated as I²S-LWR) which is being designed as part of a grant by the U.S. Department of Energy Integrated Research Project (IRP). This 969 MWe integral pressurized water reactor (PWR) incorporates as many passive safety features as possible while maintaining competitive costs with current light water reactors. In support of this work, the …

A General Code To Represent The Mathematical Life Cycle Cost Model Of Bridge, Bajel Mohammed Alshadeedi

Masters Theses

There are many factors that play a role in the overall cost of any bridge. The life cycle cost needs deep knowledge of bridge components to calculate its subcategories costs. The bridge life cycle cost is divided into; agency, user cost, and society costs. The agency cost includes the expected value of the final bridge construction cost, the inspection cost, better value of repainting cost, and replacing asphaltic deck cost. The user cost includes traffic delay cost and vehicle operation cost under different traffic conditions, accident cost, and failure cost. The society cost includes aesthetical and environmental impact. All costs …

Dynamic Warehouse Optimization Using Predictive Analytics., Parvaneh Jahani

Electronic Theses and Dissertations

The forward area is a small area of a warehouse with a low picking cost. Two approaches that are investigated for selecting the SKUs of this area and the allocated space are the static and the dynamic approaches. In the case that decisions about the forward area are made periodically (e.g. yearly) and the products' demand patterns are completely ignored, the FRP is static. We developed two heuristics that solve the large discrete assignment, allocation, and sizing problem simultaneously. Replenishing the same product in the same place of the forward area brings about a ``Locked" layout of the fast picking …

Optimization Models And Algorithms For Demand Response In Smart Grid., Guangyang Xu

Electronic Theses and Dissertations

For demand response in smart grid, a utility company wants to minimize total electricity cost and end users want to maximize their own utility. The latter is considered to consist of two parts in this research: electricity cost and convenience/comfort. We first develop a system optimal (SO) model and a user equilibrium (UE) model for the utility company and end users, respectively and compare the difference of the two. We consider users' possible preference on convenience over cost-saving under the real-time pricing in smart grid, and each user is assumed to have a preferred time window for using a particular …

Order Picking Strategies For Healthcare Warehouses., Ehsan Khodabandeh

Electronic Theses and Dissertations

Order picking is the process of collecting goods and items in specified quantities from storage locations, in response to customer orders. Since many labor resources are involved in this process, finding ways to make it more efficient have been a primary goal for researchers and practitioners. Determining a better allocation of products to the storage areas, finding the best route and sequence to pick multiple products, and choosing the best picking policies to minimize congestion in the aisles are just a few of many objectives regarding order picking process. Due to regulatory compliances and the chance of product spoilage, additional …

Simulation Modeling For Energy Consumption Of Residential Consumers In Response To Demand Side Management., Prajwal Khadgi

Electronic Theses and Dissertations

Energy efficiency in the electricity distribution system continues to gain importance as demand for electricity keeps rising and resources keep diminishing. Achieving higher energy efficiency by implementing control strategies and demand response (DR) programs has always been a topic of interest in the electric utility industry. The advent of smart grids with enhanced data communication capabilities propels DR to be an essential part of the next generation power distribution system. Fundamentally, DR has the ability to charge a customer the true price of electricity at the time of use, and the general perception is that consumers would shift their load …

Effective Supplier Quality Practices In The Construction Industry, Ashleigh Hegwood

Industrial Engineering Undergraduate Honors Theses

The dynamic and irregular nature of projects in the construction industry causes the complexity of supplier quality management (SQM). The Construction Industry Institute (CII) Research Team (RT) 308 is focused on achieving zero rework through effective supplier quality practices.

This honors thesis is an extension of RT 308’s project work. Its purpose is to look at current supplier evaluation practices within the construction industry, confirm arecommended supplier cutoff rating through data analysis, and determine if outliers in the data set could be normalized. A survey was developed in Qualtrics (an online survey software tool) and sent to CII members for …

Grouping Techniques To Manage Large-Scale Multi-Item Multi-Echelon Inventory Systems, Anvar Abaydulla

Graduate Theses and Dissertations

Large retail companies operate large-scale systems which may consist of thousands of stores. These retail stores and their suppliers, such as warehouses and manufacturers, form a large-scale multi-item multi-echelon inventory supply network. Operations of this kind of inventory system require a large number of human resources, computing capacity, etc.

In this research, three kinds of grouping techniques are investigated to make the large-scale inventory system “easier” to manage. The first grouping technique is a network based ABC classification method. A new classification criterion is developed so that the inventory network characteristics are included in the classification process, and this criterion …

Safety Performance Prediction Of Large-Truck Drivers In The Transportation Industry, Emily Moneka Francis Xavier

Graduate Theses and Dissertations

The trucking industry and truck drivers play a key role in the United States commercial transportation sector. Accidents involving large trucks is one such big event that can cause huge problems to the driver, company, customer and other road users causing property damage and loss of life. The objective of this research is to concentrate on an individual transportation company and use their historical data to build models based on statistical and machine learning methods to predict accidents. The focus is to build models that has high accuracy and correctly predicts an accident. Logistic regression and penalized logistic regression models …

Design And Prototyping Of An Adjustable Putter, Daulton Morgan

Industrial and Manufacturing Engineering

Being able to demo a golf putter is essential for a golfer since the feel of the putter is critical in determining what suits the golfer best. Due to the market being primarily dominated by right-handed players, it is difficult for left-handed players to demo high quality putters since the selection is sparse.

This report is about designing and integrating an interchangeable fastening system that allows a putter to be altered between a right and left-handed orientation, while still maintaining the traditional look of a putter. The report covers the necessary design steps, the prototyping of the putter, the projected …