Open Access. Powered by Scholars. Published by Universities.®

Operations Research, Systems Engineering and Industrial Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

Faculty Publications

Discipline
Institution
Keyword
Publication Year

Articles 31 - 60 of 150

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

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, …

Go to article

Experimental And Numerical Behavior Of Encased Pultruded Gfrp Beams Under Elevated And Ambient Temperatures, Enas M. Mahmood, Teghreed H. Ibrahim, Abbas A. Allawi, Ayman El-Zohairy May 2023

Experimental And Numerical Behavior Of Encased Pultruded Gfrp Beams Under Elevated And Ambient Temperatures, Enas M. Mahmood, Teghreed H. Ibrahim, Abbas A. Allawi, Ayman El-Zohairy

Faculty Publications

In this research, experimental and numerical studies were carried out to investigate the performance of encased glass-fiber-reinforced polymer (GFRP) beams under fire. The test specimens were divided into two peer groups to be tested under the effect of ambient and elevated temperatures. The first group was statically tested to investigate the monotonic behavior of the specimens. The second group was exposed to fire loading first and then statically tested to explore the residual behavior of the burned specimens. Adding shear connectors and web stiffeners to the GFRP beam was the main parameter in this investigation. Moreover, service loads were applied …

Go to article

Numerical Modeling And Analysis Of Strengthened Steel–Concrete Composite Beams In Sagging And Hogging Moment Regions, Ayman El-Zohairy, Suzan Mustafa, Hesham Shaaban, Hani Salim Apr 2023

Numerical Modeling And Analysis Of Strengthened Steel–Concrete Composite Beams In Sagging And Hogging Moment Regions, Ayman El-Zohairy, Suzan Mustafa, Hesham Shaaban, Hani Salim

Faculty Publications

Strengthening of composite beams is highly needed to upgrade the capacities of existing beams. The strengthening methods can be classified as active or passive techniques. Therefore, the main purpose of this study is to provide detailed FE simulations for strengthened and unstrengthened steel–concrete composite beams at the sagging and hogging moment regions with and without profiled steel sheeting. The developed models were verified against experimental results from the literature. The verified models were used to present comparisons between the effect of using external post-tensioning and CFRP laminates as strengthening techniques. Applying external post-tensioning at the sagging moment regions is more …

Go to article

Experimental Investigation Of Self-Compacting Concrete With Recycled Concrete Aggregate, Sayed Ahmed, Ayman El-Zohairy, Ahmed S. Eisa, Mohamed Abd El-Aziz Badran Mohamed Mar 2023

Experimental Investigation Of Self-Compacting Concrete With Recycled Concrete Aggregate, Sayed Ahmed, Ayman El-Zohairy, Ahmed S. Eisa, Mohamed Abd El-Aziz Badran Mohamed

Faculty Publications

Due to the depletion of natural aggregates and raw materials for contemporary construction, the construction and demolition waste existing in old concrete structures is an imperative problem. Cutting down on exploiting natural aggregates and reusing construction and demolition waste in the concrete industry are solutions to this problem. This paper investigated the replacement of natural coarse aggregate (NCA) with recycled concrete aggregates (RCA) with different ratios (0%, 50%, 75%, and 100%) in producing self-compacting concrete (SCC). Different components of supplementary cementitious materials (SCMs), such as nano-silica (NS), fly ash (FA), and metakaolin (MK), as well as PVA fibers, were incorporated …

Go to article

Prestressed Steel-Concrete Composite I-Beams With Single And Double Corrugated Web, Mahmoud T. Nawar, Ayman El-Zohairy, Hassan M. Maaly, Mohammed Husain Feb 2023

Prestressed Steel-Concrete Composite I-Beams With Single And Double Corrugated Web, Mahmoud T. Nawar, Ayman El-Zohairy, Hassan M. Maaly, Mohammed Husain

Faculty Publications

Composite steel girders with concrete have been used for many years and advances in structural and fabrication technology have established their optimization. One of the changes in structural steel I-beams during the past few years has been the availability of web corrugation. The economic design of steel girders normally requires thin webs. Moreover, using externally prestressed tendons as a strengthening technique controls deflections and stresses. However, this strengthening technique causes shear buckling of the steel beams. In this study, the flexural behavior of externally prestressed composite steel-concrete I-beams with a single and double corrugated web was experimentally and numerically investigated. …

Go to article

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 …

Go to article

Performance Of Rubberized Concrete And The Effect Of Temperature And Stainless Steel Fibers, Ayman El-Zohairy, Matthew Sanchez, Bahram Abediniangerabi, Perry Moler Jan 2023

Performance Of Rubberized Concrete And The Effect Of Temperature And Stainless Steel Fibers, Ayman El-Zohairy, Matthew Sanchez, Bahram Abediniangerabi, Perry Moler

Faculty Publications

Rubberized concrete is widely used in construction by utilizing the advantages of partially replacing fine or coarse aggregate with rubber to enhance several properties of concrete and provide an environmentally friendly solution. This paper experimentally explores the influence of utilizing crumb rubber (CR) as an alternate coarse aggregate in concrete. Concrete specimens were prepared with different percentages of rubber (0%, 5%, 10%, 15%, and 20%). Additionally, other parameters, such as freezing–thawing cycles, temperature, and stainless steel fibers (SSFs), were investigated. The workability of fresh concrete and the compression properties of hardened concrete were examined. Reductions in the mechanical properties of …

Go to article

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 …

Go to article

Effect Of Using Ecc Layer On The Flexural Performance Of Rc Beams Previously Strengthened With Eb Cfrp Laminates, Mohamed Emara, Ayman El-Zohairy, Mahmoud Fekry, Mohamed Husain Dec 2022

Effect Of Using Ecc Layer On The Flexural Performance Of Rc Beams Previously Strengthened With Eb Cfrp Laminates, Mohamed Emara, Ayman El-Zohairy, Mahmoud Fekry, Mohamed Husain

Faculty Publications

This paper studies the efficiency of applying an engineered cementitious composite (ECC) layer to the tensile surface of (RC) beams that were previously strengthened using externally bonded (EB) carbon fiber-reinforced polymer (CFRP) laminates. One control and ten strengthened RC beams were produced and tested utilizing a four-point loading regime. For strengthened beams, two beams were kept strengthened using only CFRP, and additional ECC layers were added to the rest of the strengthened beams. The CFRP width and overlap length and position were among the test factors. Experimental results revealed that strengthening RC beams with CFRP laminates enhanced both the stiffness …

Go to article

Analysis And Residual Behavior Of Encased Pultruded Gfrp I-Beam Under Fire Loading, Enas M. Mahmood, Abbas A. Allawi, Ayman El-Zohairy Oct 2022

Analysis And Residual Behavior Of Encased Pultruded Gfrp I-Beam Under Fire Loading, Enas M. Mahmood, Abbas A. Allawi, Ayman El-Zohairy

Faculty Publications

In this paper, fire resistance and residual capacity tests were carried out on encased pultruded glass fiber-reinforced polymer (GFRP) I-beams with high-strength concrete beams. The specimens were loaded concurrently under 25% of the ultimate load and fire exposure (an increase in temperature of 700 C) for 70 min. Subsequently, the fire-damaged specimens were allowed to cool and then were loaded statically until failure to explore the residual behaviors. The effects of using shear connectors and web stiffeners on the residual behavior were investigated. Finite Element (FE) analysis was developed to simulate the encased pultruded GFRP I-beams under the effect of …

Go to article

Effect Of Supporting Base System On The Flexural Behavior And Toughness Of The Lighting Gfrp Poles, Mahmoud T. Nawar, Mostafa E. Kaka, Ayman El-Zohairy, Osama Elhosseiny Oct 2022

Effect Of Supporting Base System On The Flexural Behavior And Toughness Of The Lighting Gfrp Poles, Mahmoud T. Nawar, Mostafa E. Kaka, Ayman El-Zohairy, Osama Elhosseiny

Faculty Publications

Due to the high risk of common traffic electric poles, the use of glass fiber reinforced polymer (GFRP) material in electric poles has become essential due to its excellent advantages such as high strength to weight ratio, corrosion resistance, and electrical insulation, which keeps people safe. To reduce the accidental effect of street lighting poles on humans, the generated energy during the collision must be absorbed. Experimental and numerical investigations were carried out to identify the efficiency of tapered GFRP electric poles with handle doors using steel sleeve bases until the occurrence of failure. Six full-scale cantilever bending tests were …

Go to article

Innovation Transition Success: Practice Doesn't Make Perfect, Kaitlyn Ryan, Amy M. Cox, Ethan Blake, Clay Koschnick, Alfred E. Thal Jr. Oct 2022

Innovation Transition Success: Practice Doesn't Make Perfect, Kaitlyn Ryan, Amy M. Cox, Ethan Blake, Clay Koschnick, Alfred E. Thal Jr.

Faculty Publications

The authors of this research examine and evaluate organizational factors associated with commercialization under the Air Force Small Business Innovation Research (SBIR) program. Their objective is to improve return on investment. The data set used was the SBIR Phase II program data set, which contains information on 433 SBIR topics with closed contracts reported during Department of Defense (DoD) fiscal years (FYs) 2015 to 2018. Each data point contained characteristics of the topic, including commercialization. Military capability or topic areas were hypothesized to have varying commercialization rates. Incumbency was theorized to be a characteristic of successful programs, while increased company …

Go to article

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 …

Go to article

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.

Go to article

Flexural Performance Of Encased Pultruded Gfrp I-Beam With High Strength Concrete Under Static Loading, Enas M. Mahmood, Abbas A. Allawi, Ayman El-Zohairy Jun 2022

Flexural Performance Of Encased Pultruded Gfrp I-Beam With High Strength Concrete Under Static Loading, Enas M. Mahmood, Abbas A. Allawi, Ayman El-Zohairy

Faculty Publications

There is an interesting potential for the use of GFRP-pultruded profiles in hybrid GFRP concrete structural elements, either for new constructions or for the rehabilitation of existing structures. This paper provides experimental and numerical investigations on the flexural performance of reinforced concrete (RC) specimens composite with encased pultruded GFRP I-sections. Five simply supported composite beams were tested in this experimental program to investigate the static flexural behavior of encased GFRP beams with high-strength concrete. Besides, the effect of using shear studs to improve the composite interaction between the GFRP beam and concrete as well as the effect of web stiffeners …

Go to article

Environmental Impact On The Behavior Of Cfrp Sheet Attached To Concrete, Ayssar Al-Khafaji, Ayman El-Zohairy, Mirnes Mustafic, Hani Salim Jun 2022

Environmental Impact On The Behavior Of Cfrp Sheet Attached To Concrete, Ayssar Al-Khafaji, Ayman El-Zohairy, Mirnes Mustafic, Hani Salim

Faculty Publications

Carbon fiber-reinforced polymer (CFRP) has many advantages as a construction/structural strengthening material. However, there are still concerns regarding the long-term performance of these materials when used with reinforced concrete (RC) structures. Environmental conditions have an adverse effect on the behavior of CFRP and the bond between these sheets and concrete. Therefore, the durability of CFRP used for strengthening RC beams was evaluated under different environmental scenarios, including subjection to immersion in deicing agents, tap water, and saltwater, freeze-and thaw cycles, and outdoor environmental changes. Laboratory tests were performed to examine the influence of these environmental scenarios on the bonding behavior …

Go to article

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 …

Go to article

Behavior Of One-Way Reinforced Concrete Slabs With Polystyrene Embedded Arched Blocks, Ali Hussein Ali Al-Ahmed, Falah Hasan Ibrahim, Abbas Abdulmajeed Allawi, Ayman El-Zohairy Mar 2022

Behavior Of One-Way Reinforced Concrete Slabs With Polystyrene Embedded Arched Blocks, Ali Hussein Ali Al-Ahmed, Falah Hasan Ibrahim, Abbas Abdulmajeed Allawi, Ayman El-Zohairy

Faculty Publications

This study presents experimental and numerical investigations on seven one-way, reinforced concrete (RC) labs with a new technique of slab weight reduction using polystyrene-embedded arched blocks (PEABs). All slabs had the same dimensions, steel reinforcement, and concrete compressive strength. One of these slabs was a solid slab, which was taken as a control slab, while the other six slabs were cast with PEABs. The main variables were the ratio of the length of the PEABs to the length of the slab (lp/L) and the ratio of the height of the PEABs to the total slab depth (hP/H). The minimum decrease …

Go to article

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 …

Go to article

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 …

Go to article

Strengthening Of Continuous Reinforced Concrete Deep Beams With Large Openings Using Cfrp Strips, Mohammed Riyadh Khalaf, Ali Hussein Ali Al-Ahmed, Abbas Abdulmajeed Allawi, Ayman El-Zohairy Jun 2021

Strengthening Of Continuous Reinforced Concrete Deep Beams With Large Openings Using Cfrp Strips, Mohammed Riyadh Khalaf, Ali Hussein Ali Al-Ahmed, Abbas Abdulmajeed Allawi, Ayman El-Zohairy

Faculty Publications

To accommodate utilities in buildings, different sizes of openings are provided in the web of reinforced concrete deep beams, which cause reductions in the beam strength and stiffness. This paper aims to investigate experimentally and numerically the effectiveness of using carbon fiber reinforced polymer (CFRP) strips, as a strengthening technique, to externally strengthen reinforced concrete continuous deep beams (RCCDBs) with large openings. The experimental work included testing three RCCDBs under five-point bending. A reference specimen was prepared without openings to explore the reductions in strength and stiffness after providing large openings. Openings were created symmetrically at the center of spans …

Go to article

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.

Go to article

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.

Go to article

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.

Go to article

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 …

Go to article

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 …

Go to article

Generalized Imperfect D2d Associations In Spectrum-Shared Cellular Networks Under Transmit Power And Interference Constraints, Redha M. Radaydeh, Fawaz S. Al-Qahtani, Abdulkadir Celik, Khalid A. Qaraqe Oct 2020

Generalized Imperfect D2d Associations In Spectrum-Shared Cellular Networks Under Transmit Power And Interference Constraints, Redha M. Radaydeh, Fawaz S. Al-Qahtani, Abdulkadir Celik, Khalid A. Qaraqe

Faculty Publications

This paper studies imperfect underlay device-to-device (D2D) association in spectrum-shared cellular networks. It addresses important system and design interference constraints, processing load limitations and transmit power constraints at D2D terminals. The paper proposes decentralized schemes for D2D communication between D2D terminals when downlink channel resources can be reused in the D2D network. The D2D transmitters are characterized considering their processing load limitation and allocated transmit power constraints. Moreover, the downlink channels that can be reused in the D2D network are quantified while meeting interference constraints imposed by the primary cellular network. Two schemes to identify reusable channels, which vary in …

Go to article

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 …

Go to article

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 …

Go to article

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 …

Go to article

First Prev Next Last