Operational Research Commons^™

Modeling And Characterization Of On-Orbit Servicing Architectures For Efficient Mission Planning, Samantha Q. Vi Tang

Theses and Dissertations

As space-based systems become increasingly critical to global infrastructure, efficient satellite maintenance and resource management have become essential to ensuring operational longevity. On-orbit servicing has emerged as a key strategy for extending satellite lifespans, mitigating space debris accumulation, and enhancing the cost effectiveness of space operations. This study presents a comprehensive mixed-integer programming (MIP) model to optimize servicer task assignments and routing while minimizing propellant consumption. The model captures the operational complexities of servicing a network of satellites across multiple orbits by incorporating realistic constraints, such as fuel limitations and task completion time windows. Sensitivity analysis allows mission planners to …

Improving Military Medical Evacuation System Performance Via Stochastic Optimization, Virbon B. Frial

Theses and Dissertations

This research highlights the importance of improving the performance of military medical evacuation systems to reduce the risk of permanent disability or death among service members in deployed environments. We employ a range of stochastic optimization techniques relating to integer programming, Markov decision process, approximate dynamic programming, and machine learning, as appropriate, to gain insights into factors that contribute to improving system performance.

Connection-Saving Gate Assignment: A Computational Approach, Rob Mailley

Computer Science Senior Theses

The growth of the commercial aviation industry has yielded many interesting problems in the field of Operations Research, many of which are now able to be solved as both technology and mathematical optimization improve. A particularly interesting problem in airport operations re- search is the Aircraft Gate Assignment Problem (AGAP), which seeks to create a feasible match- ing between planes and flights at an airport. This problem is well-suited to modeling with Integer Programming, and has attracted research since the 1970s. Researchers of the AGAP have considered many different objectives, ranging from airline-focused objectives to more passenger-focused objective functions. In …

An Integer Programming Model To Optimize Us Army Deployment Cycle And Maximize Unit Availability, Grant R. Engel

Theses and Dissertations

The goal of this paper is to determine an optimal cycle length, in months, that minimizes costs and maximizes availability for deploying units in the United States (US) Army. The US Army must be cost efficient while maintaining the flexibility required to adapt to dynamic mission demand. The current practice is to deploy units for a length between the range of 6 to 12 months; however, this varies from unit to unit and the best policy is not clear. We address these issues by forming a mathematical programming model with unique characteristics that distinguish it from others of similar design. …

The Cyber Wargame Commodity Course Of Action Automated Analysis Method, Alex Hoffendahl

Theses and Dissertations

In the modern operational landscape, strategic decisions are made and executed, under uncertain conditions, with many potential constraints and limited information. The end goal of these decisions is to minimize and mitigate the effect of adversarial threats, which may or may not act in line with previous assumptions. Wargaming is a powerful tool that allows for the practical implementation of theoretical knowledge into real-world scenarios, enhancing decision-makers critical thinking and problem solving skills. Furthermore, including cyber-effects in a wargame leads to a broader decision scope for an entire operation. This research aims to enhance the analytical capabilities and overall usability …

Integrated Intermodal Network Design With Nonlinear Inter-Hub Movement Costs, Mohammad Ghane-Ezabadi, Hector A. Vergara

15th IMHRC Proceedings (Savannah, Georgia. USA – 2018)

In this research, transportation mode and load route selection problems are integrated with the hub location problem in a single mathematical formulation to find the optimal design of intermodal transportation networks. Economies of scale are modeled utilizing a stepwise function that relates the per container transportation cost to the amount of flow between two nodes. A heuristic method combining a genetic algorithm and the shortest path algorithm was developed to solve this integrated planning problem. Computational experiments were completed to evaluate the performance of the proposed heuristic for different problem instances. At the end, conclusions are presented and future research …

A Decision Modeling For Phasor Measurement Unit Location Selection In Smart Grid Systems, Seung Yup Lee

Wayne State University Theses

As a key technology for enhancing the smart grid system, Phasor Measurement Unit (PMU) provides synchronized phasor measurements of voltages and currents of wide-area electric power grid. With various benefits from its application, one of the critical issues in utilizing PMUs is the optimal site selection of units.

The main aim of this research is to develop a decision support system, which can be used in resource allocation task for smart grid system analysis. As an effort to suggest a robust decision model and standardize the decision modeling process, a harmonized modeling framework, which considers operational circumstances of component, is …

Optimization Models And Algorithms For Spatial Scheduling, Christopher J. Garcia

Engineering Management & Systems Engineering Theses & Dissertations

Spatial scheduling problems involve scheduling a set of activities or jobs that each require a certain amount of physical space in order to be carried out. In these problems space is a limited resource, and the job locations, orientations, and start times must be simultaneously determined. As a result, spatial scheduling problems are a particularly difficult class of scheduling problems. These problems are commonly encountered in diverse industries including shipbuilding, aircraft assembly, and supply chain management. Despite its importance, there is a relatively scarce amount of research in the area of spatial scheduling.

In this dissertation, spatial scheduling problems are …

Computer-Based Methods For Constructing Two-Level Fractional-Factorial Experimental Designs With A Requirement Set, Steven L. Forsythe

Theses and Dissertations

This dissertation developed four methodologies for computer-aided experimental design of two-level fractional factorial designs with requirement sets (DOE/RS). The requirement sets identify all the experimental factors and the appropriate interaction terms to be evaluated in the experiment. Taguchi graphs and similar manual methods provide techniques for solving the DOE/RS problem. Unfortunately, these methods are limited because they become difficult to use as the number of factors or interaction terms exceeds ten. This research showed that the DOE/RS problem belongs to a class of difficult-to-solve problems known as NP-Complete. It is the combinatorial nature of NP-Complete problems that causes them to …

An Integer Solution Heuristic For The Arsenal Exchange Model (Aem), Daniel J. Green

Theses and Dissertations

The Air Force Studies and Analyses Agency sought a method for converting the continuous solution produced by the Arsenal Exchange Model into a feasible integer solution. The current integerization method leaves weapons unused and targets uncovered and could be improved. In the method developed, the noninteger valued variables in the continuous solution are rounded down to the nearest integer to produce a truncated solution. An integer goal program is then used to reallocate the weapons and targets made available in the rounding process. The truncated solution is then combined with the solution of the integer goal program to produce a …

Optimal Silo Attack Plan For The Red Integrated Strategic Offensive Plan (Risop), Richard C. Pace

Theses and Dissertations

The Joint Staff Directorate for Force Structure, Resources, and Assessment (J-8) sought a procedure which could be used to generate an optimal missile allocation for the silo attack portion of the Red Integrated Strategic Offensive Plan (RISOP). Their current solution procedure is a manual heuristic which is time-consuming and is not guaranteed to lead to an optimal solution. J- 8 defines an optimal solution as a feasible solution which minimizes both the flight time of the missile that impacts first and the duration of the attack. J- 8 defined several input rules which limit how missiles may be allocated. A …

A Solution Methodology For The Variable-Level Scheduling Problem, Dennis R. Benson

Theses and Dissertations

This study looked at a specific scheduling problem for a Department of Defense agency. A heuristic algorithms was developed to solve a general variable-level scheduling problem and was applied to this specific problem. This heuristic used linear programming and integer programming to find the minimum number of weekly billable hours for five alternative schedules. The best alternative schedule was further developed into a spreadsheet designed, squad level, master schedule. The result of this study was a proposed schedule that would save the United States government 8.2% of their security costs for this one part of the governmental agency. These savings …

Investigation Of A Zero-One Integer Programming Approach To Automating The Scheduling Process At The Usaf Test Pilot School, Lisa M. Hassel

Theses and Dissertations

This thesis investigated models that could be used to determine a feasible schedule for the Test Pilot School (TPS) training program and form the basis for an automated scheduling system. The TPS problem is formulated as a 0-1 integer linear program and is solved using preprocessing techniques and the Branch-and-Bound algorithm. The method produced feasible solutions for small problems that equate to portions of the TPS schedule but cannot efficiently solve large problems like the full TPS problem. More investigation should be conducted to alter the method developed in the study so it could be used for large problems. A …