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

The Characteristics Of Successful Military It Projects: A Cross-Country Empirical Study, Helene Berg, Jonathan D. Ritschel Jul 2023

The Characteristics Of Successful Military It Projects: A Cross-Country Empirical Study, Helene Berg, Jonathan D. Ritschel

Faculty Publications

No abstract provided.


Domain Restriction Zones: An Evolution Of The Military Exclusion Zone, Cole M. Mooty, Robert A. Bettinger, Mark G. Reith Jul 2023

Domain Restriction Zones: An Evolution Of The Military Exclusion Zone, Cole M. Mooty, Robert A. Bettinger, Mark G. Reith

Faculty Publications

Since the early part of the twenty-first century, US adversaries have expanded their military capabilities within and their access to new warfighting domains. When faced with the growth of adversaries’ asymmetric capabilities, the means, tactics, and strategies previously used by the US military lose their proportional effectiveness. To avoid such degradation of capability, the operational concept of the military exclusion zone (MEZ) should be revised to suit the modern battlespace while also addressing the shifts in national policy that encourage diplomacy over military force. The concept and development of domain restriction zones (DRZs) increase the relevancy of traditional MEZs in …


Empowering Student Success: Unlocking The Potential Of Project-Based Steel Design Education, Aly Mousaad Aly Jun 2023

Empowering Student Success: Unlocking The Potential Of Project-Based Steel Design Education, Aly Mousaad Aly

Faculty Publications

In the pursuit of student success, it is essential to acknowledge that a singular teaching style does not universally cater to all students. The educator's crucial role lies in creating an optimal learning environment that fosters students' endeavors to excel. This endeavor transcends mere classroom success or employment prospects, encompassing a broader impact on societal well-being. An experiential learning approach, where students actively engage in practical tasks, emerges as the most effective mode of instruction. Integrating project-based learning activities into the curriculum holds immense potential for enhancing student learning. Additionally, the utilization of analysis software tools like FTool and STAAD …


Imparting Systems Engineering Experience Via Interactive Fiction Serious Games, Thomas C. Ford, David Long, Echo Ford * Jun 2023

Imparting Systems Engineering Experience Via Interactive Fiction Serious Games, Thomas C. Ford, David Long, Echo Ford *

Faculty Publications

Serious games for education are becoming increasing popular. Interactive fiction games are some of the most popular in app stores and are also beginning to be heavily used in education to teach analysis and decision-making. Noting that it is difficult for systems engineers to experience all necessary situations which prepare them for the role of a chief engineer, in this paper, we explore the use of interactive fiction serious games to impart systems engineering experience and to teach systems engineering principles. The results of a cognitive viability, qualitative viability, and replayability analysis of 14 systems engineering serious games developed in …


Effects Of Individual Strategies For Resource Access On Collaboratively Maintained Irrigation Infrastructure, Jordan L. Stern, Afreen Siddiqi, Paul N. Grogan Jun 2023

Effects Of Individual Strategies For Resource Access On Collaboratively Maintained Irrigation Infrastructure, Jordan L. Stern, Afreen Siddiqi, Paul N. Grogan

Faculty Publications

Built infrastructure for water and energy supply, transportation, and other such services underpins human well-being and socioeconomic development. A fundamental understanding of how infrastructure design and user strategies interact can guide important design decisions as well as policy formulation for ensuring long-term infrastructure viability in conjunction with improved individual user benefits. In this work, an agent based model (ABM) is developed to study this issue for the specific case of irrigation canals. Cooperatively maintained irrigation canals serve essential roles in sustaining agriculture-based economies in many regions. Canal system design can strongly affect benefits derived by distributed users, regional agricultural output, …


Ads-B Classification Using Multivariate Long Short-Term Memory–Fully Convolutional Networks And Data Reduction Techniques, Sarah Bolton *, Richard Dill, Michael R. Grimaila, Douglas Hodson Feb 2023

Ads-B Classification Using Multivariate Long Short-Term Memory–Fully Convolutional Networks And Data Reduction Techniques, Sarah Bolton *, Richard Dill, Michael R. Grimaila, Douglas Hodson

Faculty Publications

Researchers typically increase training data to improve neural net predictive capabilities, but this method is infeasible when data or compute resources are limited. This paper extends previous research that used long short-term memory–fully convolutional networks to identify aircraft engine types from publicly available automatic dependent surveillance-broadcast (ADS-B) data. This research designs two experiments that vary the amount of training data samples and input features to determine the impact on the predictive power of the ADS-B classification model. The first experiment varies the number of training data observations from a limited feature set and results in 83.9% accuracy (within 10% of …


Machine Learning Prediction Of Dod Personal Property Shipment Costs, Tiffany Tucker [*], Torrey J. Wagner, Paul Auclair, Brent T. Langhals Jan 2023

Machine Learning Prediction Of Dod Personal Property Shipment Costs, Tiffany Tucker [*], Torrey J. Wagner, Paul Auclair, Brent T. Langhals

Faculty Publications

U.S. Department of Defense (DoD) personal property moves account for 15% of all domestic and international moves - accurate prediction of their cost could draw attention to outlier shipments and improve budget planning. In this work 136,140 shipments between 13 personal property shipment hubs from April 2022 through March 2023 with a total cost of $1.6B were analyzed. Shipment cost was predicted using recursive feature elimination on linear regression and XGBoost algorithms, as well as through neural network hyperparameter sweeps. Modeling was repeated after removing 28 features related to shipment hub location and branch of service to examine their influence …


Artificial Neural Networks And Gradient Boosted Machines Used For Regression To Evaluate Gasification Processes: A Review, Owen Sedej, Eric Mbonimpa, Trevor Sleight, Jeremy M. Slagley Aug 2022

Artificial Neural Networks And Gradient Boosted Machines Used For Regression To Evaluate Gasification Processes: A Review, Owen Sedej, Eric Mbonimpa, Trevor Sleight, Jeremy M. Slagley

Faculty Publications

Waste-to-Energy technologies have the potential to dramatically improve both the natural and human environment. One type of waste-to-energy technology that has been successful is gasification. There are numerous types of gasification processes and in order to drive understanding and the optimization of these systems, traditional approaches like computational fluid dynamics software have been utilized to model these systems. The modern advent of machine learning models has allowed for accurate and computationally efficient predictions for gasification systems that are informed by numerous experimental and numerical solutions. Two types of machine learning models that have been widely used to solve for quantitative …


Beyond The High Ground: A Taxonomy For Earth-Moon System Operations, Adam P. Wilmer, Robert A. Bettinger Jul 2022

Beyond The High Ground: A Taxonomy For Earth-Moon System Operations, Adam P. Wilmer, Robert A. Bettinger

Faculty Publications

Situational and space domain awareness in the space domain can no longer be confined to that which is found in geosynchronous orbit. International activities—commercial and military—and threats to the planet itself exist and are increasing across the entire Earth-Moon system. This reality requires a new taxonomy to accurately classify space domain awareness missions and better apply resources to and development of the same. This work presents such a taxonomy for the classification of space domain awareness regions.


A Unified View Of A Human Digital Twin, Michael Miller, Emily Spatz Jun 2022

A Unified View Of A Human Digital Twin, Michael Miller, Emily Spatz

Faculty Publications

The term human digital twin has recently been applied in many domains, including medical and manufacturing. This term extends the digital twin concept, which has been illustrated to provide enhanced system performance as it combines system models and analyses with real-time measurements for an individual system to improve system maintenance. Human digital twins have the potential to change the practice of human system integration as these systems employ real-time sensing and feedback to tightly couple measurements of human performance, behavior, and environmental influences throughout a product’s life cycle to human models to improve system design and performance. However, as this …


A Simulation–Optimization Framework For Post-Disaster Allocation Of Mental Health Resources, Stephen Cunningham, Steven J. Schuldt, Christopher M. Chini, Justin D. Delorit Dec 2021

A Simulation–Optimization Framework For Post-Disaster Allocation Of Mental Health Resources, Stephen Cunningham, Steven J. Schuldt, Christopher M. Chini, Justin D. Delorit

Faculty Publications

Extreme events, such as natural or human-caused disasters, cause mental health stress in affected communities. While the severity of these outcomes varies based on socioeconomic standing, age group, and degree of exposure, disaster planners can mitigate potential stress-induced mental health outcomes by assessing the capacity and scalability of early, intermediate, and long-term treatment interventions by social workers and psychologists. However, local and state authorities are typically underfunded, understaffed, and have ongoing health and social service obligations that constrain mitigation and response activities. In this research, a resource assignment framework is developed as a coupled-state transition and linear optimization model that …


Analysis Of The Effects Of Spatiotemporal Demand Data Aggregation Methods On Distance And Volume Errors, Zachary Hornberger, Bruce A. Cox, Raymond R. Hill Aug 2021

Analysis Of The Effects Of Spatiotemporal Demand Data Aggregation Methods On Distance And Volume Errors, Zachary Hornberger, Bruce A. Cox, Raymond R. Hill

Faculty Publications

Purpose — Large/stochastic spatiotemporal demand data sets can prove intractable for location optimization problems, motivating the need for aggregation. However, demand aggregation induces errors. Significant theoretical research has been performed related to the modifiable areal unit problem and the zone definition problem. Minimal research has been accomplished related to the specific issues inherent to spatiotemporal demand data, such as search and rescue (SAR) data. This study provides a quantitative comparison of various aggregation methodologies and their relation to distance and volume based aggregation errors. Design/methodology/approach — This paper introduces and applies a framework for comparing both deterministic and stochastic aggregation …


Augmenting The Space Domain Awareness Ground Architecture Via Decision Analysis And Multi-Objective Optimization, Albert R. Vasso, Richard G. Cobb, John M. Colombi, Bryan D. Little, David R. Meyer Aug 2021

Augmenting The Space Domain Awareness Ground Architecture Via Decision Analysis And Multi-Objective Optimization, Albert R. Vasso, Richard G. Cobb, John M. Colombi, Bryan D. Little, David R. Meyer

Faculty Publications

Purpose — The US Government is challenged to maintain pace as the world’s de facto provider of space object cataloging data. Augmenting capabilities with nontraditional sensors present an expeditious and low-cost improvement. However, the large tradespace and unexplored system of systems performance requirements pose a challenge to successful capitalization. This paper aims to better define and assess the utility of augmentation via a multi-disiplinary study. Design/methodology/approach — Hypothetical telescope architectures are modeled and simulated on two separate days, then evaluated against performance measures and constraints using multi-objective optimization in a heuristic algorithm. Decision analysis and Pareto optimality identifies a set …


Prioritizing Facilities Linked To Corporate Strategic Objectives Using A Fuzzy Model, Devin Depalmer, Steven J. Schuldt, Justin D. Delorit Jun 2021

Prioritizing Facilities Linked To Corporate Strategic Objectives Using A Fuzzy Model, Devin Depalmer, Steven J. Schuldt, Justin D. Delorit

Faculty Publications

Excerpt: Limited facilities operating and modernization budgets require organizations to carefully identify, prioritize and authorize projects to ensure allocated resources align with strategic objectives. Traditional facility prioritization methods using risk matrices can be improved to increase granularity in categorization and avoid mathematical error or human cognitive biases. These limitations restrict the utility of prioritizations and if erroneously used to select projects for funding, they can lead to wasted resources. This paper aims to propose a novel facility prioritization methodology that corrects these assessment design and implementation issues.


Agile Software Development: Creating A Cost Of Delay Framework For Air Force Software Factories, J. Goljan, Jonathan D. Ritschel, Scott Drylie, Edward D. White Jan 2021

Agile Software Development: Creating A Cost Of Delay Framework For Air Force Software Factories, J. Goljan, Jonathan D. Ritschel, Scott Drylie, Edward D. White

Faculty Publications

The Air Force software development environment is experiencing a paradigm shift. The 2019 Defense Innovation Board concluded that speed and cycle time must become the most important software metrics if the US military is to maintain its advantage over adversaries.1 This article proposes utilizing a cost-o­f-d­elay (CoD) framework to prioritize projects toward optimizing readiness. Cost-­of-d­elay is defined as the economic impact resulting from a delaying product delivery or, said another way, opportunity cost. In principle, CoD assesses the negative impacts resulting from changes to the priority of a project.


Integrating Cost As A Decision Variable In Wargames, Joshua N. Reese, Jonathan D. Ritschel, Brent T. Langhals, Ryan D. Engle Jan 2021

Integrating Cost As A Decision Variable In Wargames, Joshua N. Reese, Jonathan D. Ritschel, Brent T. Langhals, Ryan D. Engle

Faculty Publications

The US military can no longer afford to be reactive, leaving critical cost analyses to the months and years following operations or full-scale conflicts. By leveraging cost in wargaming as part of the Joint planning process, DOD can provide Congress and the American taxpayers a range of potential costs associated with various military engagements that reflect fiscal and operational realities.


Comparing Greedy Constructive Heuristic Subtour Elimination Methods For The Traveling Salesman Problem, Petar Jackovich, Bruce A. Cox, Raymond R. Hill Dec 2020

Comparing Greedy Constructive Heuristic Subtour Elimination Methods For The Traveling Salesman Problem, Petar Jackovich, Bruce A. Cox, Raymond R. Hill

Faculty Publications

Purpose — This paper aims to define the class of fragment constructive heuristics used to compute feasible solutions for the traveling salesman problem (TSP) into edge-greedy and vertex-greedy subclasses. As these subclasses of heuristics can create subtours, two known methodologies for subtour elimination on symmetric instances are reviewed and are expanded to cover asymmetric problem instances. This paper introduces a third novel subtour elimination methodology, the greedy tracker (GT), and compares it to both known methodologies. Design/methodology/approach — Computational results for all three subtour elimination methodologies are generated across 17 symmetric instances ranging in size from 29 vertices to 5,934 …


Civilian Pepper Spray For Self Defense: Understanding User Perception And Impact Of Design On User Performance, David Strybel, Anil R. Kumar Nov 2020

Civilian Pepper Spray For Self Defense: Understanding User Perception And Impact Of Design On User Performance, David Strybel, Anil R. Kumar

Faculty Publications

Pepper spray is widely used in the US, and is marketed as an effective self-defense device. While pepper spray can be useful in deterring an attacker, many pepper spray owners do not have any experience using it. There is a dearth of published studies that focus on civilian pepper-spray use, not to mention first time pepper-spray users. A study to analyze pepper-spray designs with first-time users, to see how the design, specifically the safety mechanism, affects response time and overall performance would be helpful. The study was conducted in 2 parts – a survey to understand user perception, and a …


Cost Estimating Using A New Learning Curve Theory For Non-Constant Production Rates, Dakotah Hogan, John J. Elshaw, Clay M. Koschnick, Jonathan D. Ritschel, Adedeji B. Badiru, Shawn M. Valentine Oct 2020

Cost Estimating Using A New Learning Curve Theory For Non-Constant Production Rates, Dakotah Hogan, John J. Elshaw, Clay M. Koschnick, Jonathan D. Ritschel, Adedeji B. Badiru, Shawn M. Valentine

Faculty Publications

Traditional learning curve theory assumes a constant learning rate regardless of the number of units produced. However, a collection of theoretical and empirical evidence indicates that learning rates decrease as more units are produced in some cases. These diminishing learning rates cause traditional learning curves to underestimate required resources, potentially resulting in cost overruns. A diminishing learning rate model, namely Boone’s learning curve, was recently developed to model this phenomenon. This research confirms that Boone’s learning curve systematically reduced error in modeling observed learning curves using production data from 169 Department of Defense end-items. However, high amounts of variability in …


United States Department Of Defense (Dod) Real Property Repair, Alterations, Maintenance, And Construction Project Contract Data: 2009–2020, Tyler Stout, Adam Teston, Brent T. Langhals, Justin D. Delorit, Carlton Hendrix, Steven J. Schuldt Oct 2020

United States Department Of Defense (Dod) Real Property Repair, Alterations, Maintenance, And Construction Project Contract Data: 2009–2020, Tyler Stout, Adam Teston, Brent T. Langhals, Justin D. Delorit, Carlton Hendrix, Steven J. Schuldt

Faculty Publications

Nearly one-half of all construction projects exceed planned costs and schedule, globally [1]. Owners and construction managers can analyze historical project performance data to inform cost and schedule overrun risk-reduction strategies. Though, the majority of open-source project datasets are limited by the number of projects, data dimensionality, and location. A significant global customer of the construction industry, the Department of Defense (DoD) maintains a vast database of historical project data that can be used to determine the sources and magnitude of construction schedule and cost overruns for many continental and international locations. The selection of data provided by the authors …


Cost Analysis Of Optimized Islanded Energy Systems In A Dispersed Air Base Conflict, Jay F. Pearson, Torrey J. Wagner, Justin D. Delorit Sep 2020

Cost Analysis Of Optimized Islanded Energy Systems In A Dispersed Air Base Conflict, Jay F. Pearson, Torrey J. Wagner, Justin D. Delorit

Faculty Publications

The United States Air Force has implemented a dispersed air base strategy to enhance mission effectiveness for near-peer conflicts. Asset dispersal places many smaller bases across a wide geographic area, which increases resupply requirements and logistical complexity. Hybrid energy systems reduce resupply requirements through sustainable, off-grid energy production. This paper presents a novel hybrid energy renewable delivery system (HERDS) model capable of (1) selecting the optimal hybrid energy system design that meets demand at the lowest net present cost and (2) optimizing the delivery of the selected system using existing Air Force cargo aircraft. The novelty of the model’s capabilities …


Strategic Decision Facilitation: Supporting Critical Assumptions Of The Human In Empirical Modeling Of Pairwise Value Comparisons, Joseph P. Kristbaum, Frank W. Ciarallo Sep 2020

Strategic Decision Facilitation: Supporting Critical Assumptions Of The Human In Empirical Modeling Of Pairwise Value Comparisons, Joseph P. Kristbaum, Frank W. Ciarallo

Faculty Publications

Modeling human decision-making is difficult. Decision-makers are typically primed with unique biases that widen the confidence interval of judgment. Therefore, it is important that the human process in the system being modeled is designed to alleviate damaging biases and assumptions in an effort to increase process consistency between decision-makers. In this experiment, it is hypothesized that coupling specific decision-facilitation methods with a specific scale range will affect the consistency between decision-makers. This article presents a multiphase experiment that examines a varying presentation mode as well as scale range to determine how value is determined in subsequent pairwise comparisons of alternatives …


Solar Photovoltaic Considerations For Operational And Warfighter Support Capabilities, Dylan Martin-Abood [*], Douglas Dudis, Torrey J. Wagner Jun 2020

Solar Photovoltaic Considerations For Operational And Warfighter Support Capabilities, Dylan Martin-Abood [*], Douglas Dudis, Torrey J. Wagner

Faculty Publications

This work highlights the fundamental mechanisms and historical perspective for military PV technology applications and addresses the operational considerations for effectively deploying PV technology. PV materials, structures and architectures have matured into competitive and readily available energy technologies based on their levelized cost of energy (LCOE). However, enhancing warfighting capabilities requires attention to systems considerations beyond cost per watt or LCOE. While PV is impractical for fighters and bombers as it can meet less than 1% of their power requirements, there are numerous areas that could benefit from the application of PV technology. For example, installing PV arrays on all …


Securing Photovoltaic (Pv) System Deployments With Data Diodes, Robert D. Larkin, Torrey J. Wagner, Barry E. Mullins Jun 2020

Securing Photovoltaic (Pv) System Deployments With Data Diodes, Robert D. Larkin, Torrey J. Wagner, Barry E. Mullins

Faculty Publications

A survey of a typical photovoltaic (PV) system with and without the cybersecurity protections of a data diode is explored. This survey includes a brief overview of Industrial Control Systems (ICS) and their relationship to the Internet of Things (IoT), Industrial Internet of Things (IIoT), and Industry 4.0 terminology. The cybersecurity features of eight data diodes are compared, and the cyber attack surface, attack scenarios, and mitigations of a typical PV system are discussed. After assessing cybersecurity, the economic considerations to purchase a data diode are considered. At 13.19 cents/kWh, the sale of 227,445 kWh is needed to fund one …


A Multi-Criteria Logistics Analysis Of Photovoltaic Modules For Remote Applications, Nathan Thomsen [*], Dimitri Papazoglou, Torrey J. Wagner, Andrew J. Hoisington, Steven J. Schuldt Jun 2020

A Multi-Criteria Logistics Analysis Of Photovoltaic Modules For Remote Applications, Nathan Thomsen [*], Dimitri Papazoglou, Torrey J. Wagner, Andrew J. Hoisington, Steven J. Schuldt

Faculty Publications

Reliable electrical power grids are frequently unavailable or inaccessible in remote locations, including developing nation communities, humanitarian relief camps, isolated construction sites, and military contingency bases. This often requires sites to rely on costly generators and continuous fuel supply. Renewable energy systems (RES) in the form of photovoltaic (PV) arrays and energy storage present a rapidly improving alternative to power these remote locations. Previous RES literature and PV optimization models focused on economics, reliability, and environmental concerns, neglecting the importance of logistics factors in remote installations. This paper proposes additional optimization variables applicable to remote PV systems and compares PV …


Applying Control Abstraction To The Design Of Human–Agent Teams, Clifford D. Johnson, Michael E. Miller, Christina F. Rusnock, David R. Jacques Apr 2020

Applying Control Abstraction To The Design Of Human–Agent Teams, Clifford D. Johnson, Michael E. Miller, Christina F. Rusnock, David R. Jacques

Faculty Publications

Levels of Automation (LOA) provide a method for describing authority granted to automated system elements to make individual decisions. However, these levels are technology-centric and provide little insight into overall system operation. The current research discusses an alternate classification scheme, referred to as the Level of Human Control Abstraction (LHCA). LHCA is an operator-centric framework that classifies a system’s state based on the required operator inputs. The framework consists of five levels, each requiring less granularity of human control: Direct, Augmented, Parametric, Goal-Oriented, and Mission-Capable. An analysis was conducted of several existing systems. This analysis illustrates the presence of each …


Optimizing The Environmental And Economic Sustainability Of Remote Community Infrastructure, Jamie E. Filer, Justin D. Delorit, Andrew J. Hoisington, Steven J. Schuldt Mar 2020

Optimizing The Environmental And Economic Sustainability Of Remote Community Infrastructure, Jamie E. Filer, Justin D. Delorit, Andrew J. Hoisington, Steven J. Schuldt

Faculty Publications

Remote communities such as rural villages, post-disaster housing camps, and military forward operating bases are often located in remote and hostile areas with limited or no access to established infrastructure grids. Operating these communities with conventional assets requires constant resupply, which yields a significant logistical burden, creates negative environmental impacts, and increases costs. For example, a 2000-member isolated village in northern Canada relying on diesel generators required 8.6 million USD of fuel per year and emitted 8500 tons of carbon dioxide. Remote community planners can mitigate these negative impacts by selecting sustainable technologies that minimize resource consumption and emissions. However, …


Applications Of Unmanned Aerial Systems (Uas): A Delphi Study Projecting Future Uas Missions And Relevant Challenges, Alberto Sigala, Brent T. Langhals Mar 2020

Applications Of Unmanned Aerial Systems (Uas): A Delphi Study Projecting Future Uas Missions And Relevant Challenges, Alberto Sigala, Brent T. Langhals

Faculty Publications

Over recent decades, the world has experienced a growing demand for and reliance upon unmanned aerial systems (UAS) to perform a broad spectrum of applications to include military operations such as surveillance/reconnaissance and strike/attack. As UAS technology matures and capabilities expand, especially with respect to increased autonomy, acquisition professionals and operational decision makers must determine how best to incorporate advanced capabilities into existing and emerging mission areas. This research seeks to predict which autonomous UAS capabilities are most likely to emerge over the next 20 years as well as the key challenges for implementation for each capability. Employing the Delphi …


A Sequential Partial Information Bomber‐Defender Shooting Problem, Krishna Kalyanam, David W. Casbeer, Meir Pachter Feb 2020

A Sequential Partial Information Bomber‐Defender Shooting Problem, Krishna Kalyanam, David W. Casbeer, Meir Pachter

Faculty Publications

No abstract provided.


A Scenario-Based Parametric Analysis Of The Army Personnel-To-Assignment Matching Problem, Matthew D. Ferguson, Raymond R. Hill, Brian J. Lunday Jan 2020

A Scenario-Based Parametric Analysis Of The Army Personnel-To-Assignment Matching Problem, Matthew D. Ferguson, Raymond R. Hill, Brian J. Lunday

Faculty Publications

This study aims to compare linear programming and stable marriage approaches to the personnel assignment problem under conditions of uncertainty. Robust solutions should exhibit reduced variability of solutions in the presence of one or more additional constraints or problem perturbations added to some baseline problems.
Several variations of each approach are compared with respect to solution speed, solution quality as measured by officer-to-assignment preferences and solution robustness as measured by the number of assignment changes required after inducing a set of representative perturbations or constraints to an assignment instance. These side constraints represent the realistic assignment categorical priorities and limitations …