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

ℓ-Ctp: Utilizing Multiple Agents To Find Efficient Routes In Disrupted Networks, Andrew Alseth Dec 2020

ℓ-Ctp: Utilizing Multiple Agents To Find Efficient Routes In Disrupted Networks, Andrew Alseth

Graduate Theses and Dissertations

Recent hurricane seasons have demonstrated the need for more effective methods of coping with flooding of roadways. A key complaint of logistics managers is the lack of knowledge when developing routes for vehicles attempting to navigate through areas which may be flooded. In particular, it can be difficult to re-route large vehicles upon encountering a flooded roadway. We utilize the Canadian Traveller’s Problem (CTP) to construct an online framework for utilizing multiple vehicles to discover low-cost paths through networks with failed edges unknown to one or more agents a priori. This thesis demonstrates the following results: first, we develop the …


3d Printing For Solving Part Obscolescence, Ayman G. Alqarni Sep 2020

3d Printing For Solving Part Obscolescence, Ayman G. Alqarni

Theses and Dissertations

The purpose of this research was to highlight the issue of parts obsolescence and to highlight the possibility of using alternative methods to overcome parts shortage. Specifically, this thesis sought to answer the research question: is the three-dimensional printing technology (3D) an applicable approach to overcome part obsolescence. The research question was answered through data research and survey analysis. Notwithstanding, the diminished manufacturing sources and material shortages (DMSMS) management and other existing approaches, such as forecasting, contracting, and reverse engineering (RE), were discussed briefly in the literature review and profoundly in chapter IV to differentiate among applicable existing solutions toward …


Models For Data Analysis In Accelerated Reliability Growth, Cesar Alexander Ruiz Torres Jul 2020

Models For Data Analysis In Accelerated Reliability Growth, Cesar Alexander Ruiz Torres

Graduate Theses and Dissertations

This work develops new methodologies for analyzing accelerated testing data in the context of a reliability growth program for a complex multi-component system. Each component has multiple failure modes and the growth program consists of multiple test-fix stages with corrective actions applied at the end of each stage. The first group of methods considers time-to-failure data and test covariates for predicting the final reliability of the system. The time-to-failure of each failure mode is assumed to follow a Weibull distribution with rate parameter proportional to an acceleration factor. Acceleration factors are specific to each failure mode and test covariates. We …


Towards A Cyber-Physical Manufacturing Cloud Through Operable Digital Twins And Virtual Production Lines, Md Rakib Shahriar Jul 2020

Towards A Cyber-Physical Manufacturing Cloud Through Operable Digital Twins And Virtual Production Lines, Md Rakib Shahriar

Graduate Theses and Dissertations

In last decade, the paradigm of Cyber-Physical Systems (CPS) has integrated industrial manufacturing systems with Cloud Computing technologies for Cloud Manufacturing. Up to 2015, there were many CPS-based manufacturing systems that collected real-time machining data to perform remote monitoring, prognostics and health management, and predictive maintenance. However, these CPS-integrated and network ready machines were not directly connected to the elements of Cloud Manufacturing and required human-in-the-loop. Addressing this gap, we introduced a new paradigm of Cyber-Physical Manufacturing Cloud (CPMC) that bridges a gap between physical machines and virtual space in 2017. CPMC virtualizes machine tools in cloud through web services …


Simulation Modeling Of Cross-Dock And Distribution Center Based Supply Chains, Ghewa Al Chall May 2020

Simulation Modeling Of Cross-Dock And Distribution Center Based Supply Chains, Ghewa Al Chall

Graduate Theses and Dissertations

Companies are implementing new strategies to meet the customer requirements in terms of quality, timing, and cost. One of these strategies is cross-docking, which can be defined as the process of consolidating the products coming from different suppliers, but having the same destination, with minimal handling and almost no storage between loading and unloading of the goods. The purpose of this research is to investigate the benefits of having a cross-docking facility in a supply chain. In this research, we focus on developing discrete event simulation models using the opensource Java Simulation Library (JSL). Also, we work on augmenting an …


Improvement Of Geometric Quality Inspection And Process Efficiency In Additive Manufacturing, Yu Jin May 2020

Improvement Of Geometric Quality Inspection And Process Efficiency In Additive Manufacturing, Yu Jin

Graduate Theses and Dissertations

Additive manufacturing (AM) has been known for its ability of producing complex geometries in flexible production environments. In recent decades, it has attracted increasing attention and interest of different industrial sectors. However, there are still some technical challenges hindering the wide application of AM. One major barrier is the limited dimensional accuracy of AM produced parts, especially for industrial sectors such as aerospace and biomedical engineering, where high geometric accuracy is required. Nevertheless, traditional quality inspection techniques might not perform well due to the complexity and flexibility of AM fabricated parts. Another issue, which is brought up from the growing …


Application Of Theory Of Constraints (Toc) In Managing Project Information Constraints, Ferdinand Z. Prantl Apr 2020

Application Of Theory Of Constraints (Toc) In Managing Project Information Constraints, Ferdinand Z. Prantl

Engineering Management & Systems Engineering Projects for D. Eng. Degree

The scope of this doctoral project is the non-traditional application of Drum-Buffer-Rope (DBR) from the area of Theory of Constraints (ToC) in mitigating disruption in distribution facilities during phased upgrades caused by information constraint. The relevance of this project is that industrial equipment upgrades pose a significant risk of disrupting the operation of automated distribution facilities. It is partly due to a very high expected availability rate, as well as tight coupling with other upstream and downstream elements of the larger supply chain network. As a consequence of disruption in this scenario, losses incurred not only within the facility being …


Conduction Mapping For Quality Control Of Laser Powder Bed Fusion Additive Manufacturing, Chance M. Baxter Mar 2020

Conduction Mapping For Quality Control Of Laser Powder Bed Fusion Additive Manufacturing, Chance M. Baxter

Theses and Dissertations

A process was developed to identify potential defects in previous layers of Selective Laser Melting (SLM) Powder Bed Fusion (PBF) 3D printed metal parts using a mid-IR thermal camera to track infrared 3.8-4 m band emission over time as the part cooled to ambient temperature. Efforts focused on identifying anomalies in thermal conduction. To simplify the approach and reduce the need for significant computation, no attempts were made to calibrate measured intensity, extract surface temperature, apply machine learning, or compare measured cool-down behavior to computer model predictions. Raw intensity cool-down curves were fit to a simplified functional form designed to …


A Comparison Of Sbir Investment Methods: Afwerx Vs Legacy, Evan A. Gist Mar 2020

A Comparison Of Sbir Investment Methods: Afwerx Vs Legacy, Evan A. Gist

Theses and Dissertations

The AFWERX Open Topic (AOT) program uses funding from the United States Air Force’s (USAF) Small Business Innovation and Research (SBIR) budget to adapt commercial technology to USAF needs. The AOT approach to small business investment is markedly different from that of legacy SBIR investment methods. This research is a comparison of processes and outcomes for AOT and legacy SBIR. The first axis of comparison is on commercialization rates. Applying a legacy definition of commercialization on a sample of AOT contracts, we found AOT’s commercialization to be 37% (compared to an 8.8% for legacy SBIR). We caveat this finding by …


Dual-Axis Solar Tracker, Bryan Kennedy Jan 2020

Dual-Axis Solar Tracker, Bryan Kennedy

All Undergraduate Projects

Renewable energies, and fuels that are not fossil fuel-based, are one of the prolific topics of debate in modern society. With climate change now becoming a primary focus for scientists and innovators of today, one of the areas for the largest amount of potential and growth is that of the capturing and utilization of Solar Energy. This method involves using a mechanical system to track the progression of the sun as it traverses the sky throughout the day. A dual-axis solar tracker such as the one designed and built for this project, can follow the sun both azimuthally and in …


The Effect Of Cutting Condition Selection On Tool Life In Sand Milling, Craig Ertl Jan 2020

The Effect Of Cutting Condition Selection On Tool Life In Sand Milling, Craig Ertl

Dissertations and Theses @ UNI

This study was completed to address the problem of determining what effect selected cutting conditions have on tool wear and tool life in robotic sand milling (RSM) operations. The purpose of this study was to analyze the tool wear mechanisms and characteristics that govern the RSM process. The purpose was also to establish an experimental methodology that may be used in future studies to assess tool life when examining various tooling materials and designs, as well as additional sand workpiece materials. Completing this research allowed the machining process to be optimized by analyzing differences in tooling cost with variable values …


Understanding And Measuring Net Positive Business Strategies, Luke Ruffner Robinson Jan 2020

Understanding And Measuring Net Positive Business Strategies, Luke Ruffner Robinson

Graduate Student Theses, Dissertations, & Professional Papers

Despite their attempts to mitigate ecological impacts through sustainability initiatives, businesses are a major cause of the world's ecological problems. Some progressive businesses are attempting to move beyond “net zero” in terms of achieving neutral environmental impacts and instead are now pursuing a goal of net positive. Net positive refers to the idea that business activities could contribute value-added benefits to earth’s ecological systems, for example, by using technologies that sequester and store carbon. However, except for a handful of high-profile corporate case studies, little is known about how companies are developing their strategies to become net positive and …


Tolerance Intervals For Time Series Models And Specifying Trimming/Winsorizing Cutoffs, Kedai Cheng Jan 2020

Tolerance Intervals For Time Series Models And Specifying Trimming/Winsorizing Cutoffs, Kedai Cheng

Theses and Dissertations--Statistics

Confidence intervals are used to capture a parameter of interest, usually a mean or a quantile, at a specified confidence level. Prediction intervals are another practical interval that aim at making sound predictions of future values with some confidence. Although these are useful inference tools, neither of them gives people a plausible range of the sampled population. Tolerance intervals are such an inference tool that captures a specified proportion of the sampled population at a predetermined confidence level. In this dissertation, tolerance intervals for an autoregressive process with order p are constructed. In addition, a method of utilizing tolerance interval …


Implications Of Variability Of Electromyographic Measurements For Assessing Localized Muscle Fatigue, Hamad Nasser Alasim Jan 2020

Implications Of Variability Of Electromyographic Measurements For Assessing Localized Muscle Fatigue, Hamad Nasser Alasim

Graduate Theses, Dissertations, and Problem Reports

The impact of work-related musculoskeletal disorders (WMSDs) is enormous due to a combination of direct and indirect costs associated with healthcare, lost workdays and human suffering. Because of the established relationship between Localized Muscle Fatigue (LMF) development and WMSDs, and in order to reduce and/or prevent WMSDs in workplaces, different fatigue assessment methods have been developed. Surface Electromyography (SEMG) is a commonly used LMF assessment technique. The SEMG signals are typically analyzed in time and frequency domains to predict LMF based on a relative change with respect to initial, or under no-fatigue conditions. Quantifying such change, however, relies on the …