Digital Commons Network^™

Opensim-Based Musculoskeletal Modeling: Foundation For Interactive Obstetric Simulator, Bahador Dodge

Electrical & Computer Engineering Theses & Dissertations

The use of mathematical and computational models to understand complex biological systems, such as the human birth process, is a rapidly growing field in medicine. These models can be used to optimize and personalize medical treatments for individual patients, enhance training, and aid in educational efforts. While recent advancements in healthcare, particularly in obstetrics, have improved care for mothers and babies, studies and government reports indicate a rising rate of maternal mortality in the United States.

Despite this rising trend, there is a lack of detailed studies concerning the use of modeling and simulation to develop an interactive obstetrics simulator …

Development Of Modeling And Simulation Platform For Path-Planning And Control Of Autonomous Underwater Vehicles In Three-Dimensional Spaces, Sai Krishna Abhiram Kondapalli

Mechanical & Aerospace Engineering Theses & Dissertations

Autonomous underwater vehicles (AUVs) operating in deep sea and littoral environments have diverse applications including marine biology exploration, ocean environment monitoring, search for plane crash sites, inspection of ship-hulls and pipelines, underwater oil rig maintenance, border patrol, etc. Achieving autonomy in underwater vehicles relies on a tight integration between modules of sensing, navigation, decision-making, path-planning, trajectory tracking, and low-level control. This system integration task benefits from testing the related algorithms and techniques in a simulated environment before implementation in a physical test bed. This thesis reports on the development of a modeling and simulation platform that supports the design and …

Risk-And-Resiliency-Intelligent Supply Chain (Rrisc), Ahmad A. Abdelnabi, Ahmed M. Abdelmagid, Ghaith Rabadi, Andres Sousa-Poza, C. Ariel Pinto

Modeling, Simulation and Visualization Student Capstone Conference

This work proposes a risk-and-resiliency-intelligent supply chain (RRiSC) tool which is an SC risk management framework that leverages cutting-edge technologies in Artificial Intelligence (AI), Big Data Analytics (BDA), and Digital Twins (DT) to develop specific capabilities for SC risk management. RRiSC is a convergence of mature tools and techniques embedded in three modules: Modeling, Simulation, and Visualization – all together integrate the optimization, simulation, and data analytics to test the performance of the whole supply network under different scenarios through measuring the vital KPIs, identifying the vulnerabilities, and setting proactive plans to diminish risks consequences.

Development Of A Framework To Support Informed Shipbuilding Based On Supply Chain Disruptions, Katherine Smith, Rafael Diaz, Yuzhong Shen

VMASC Publications

In addition to stresses induced by the Covid-19 pandemic, supply chains worldwide have been growing more complex while facing a continuous onslaught of disruptions. This paper presents an analysis and extension of a graph based model for modeling and simulating the effects of such disruptions. The graph based model combines a Bayesian network approach for simulating risks with a network dependency analysis approach for simulating the propagation of disruptions through the network over time. The initial analysis provides evidence supporting extension to for using a multi-layered approach allowing for the inclusion of cyclic features in supply chain models. Initial results …

Exploring Blockchain Adoption Supply Chains: Opportunities And Challenges, Adrian V. Gheorghe, Omer F. Keskin, Farinaz Sabz Ali Pour

Engineering Management & Systems Engineering Faculty Publications

In modern supply chains, acquisition often occurs with the involvement of a network of organizations. The resilience, efficiency, and effectiveness of supply networks are crucial for the viability of acquisition. Disruptions in the supply chain require adequate communication infrastructure to ensure resilience. However, supply networks do not have a shared information technology infrastructure that ensures effective communication. Therefore decision-makers seek new methodologies for supply chain management resilience. Blockchain technology offers new decentralization and service delegation methods that can transform supply chains and result in a more flexible, efficient, and effective supply chain. This report presents a framework for the application …

Creating A Driving Workload Model And Identifying Best Practices, Josalin Kumm, Holly Handley, Yusuke Yamani

Psychology: Interdisciplinary Research in Behavioral Sciences of Transportation Issues

One major way to investigate distracted driving is to have drivers engage in a secondary task. Driving models are one way to better understand workload during driving which could result in safer driving. During this study, we create a driving model using cognitive task analysis software to analyze workload with N-Back tasks. N-Back task requires the driver to memorize and repeat numbers and letters. The result will help us determine if we can continue using this software in future research and analysis workload in a scenario with secondary tasks by comparing it to other analysis software in the framework of …

Theoretical Analysis Of Experimental Data Of Sodium Diffusion In Oxidized Molybdenum Thin Films, Orlando Ayala, Benjamin Belfore, Tasnuva Ashrafee, John Akwari, Grace Rajan, Shankar Karki, Deewakar Poudel, Sylvain Marsillac

Engineering Technology Faculty Publications

In this work, the diffusion process of sodium (Na) in molybdenum (Mo) thin films while it was deposited on soda lime glass (SLG) was studied. A small amount of oxygen was present in the chamber while the direct-current (DC) magnetron sputtering was used for the deposition. The substrate temperatures were varied to observe its effect. Such molybdenum films, with or without oxidations, are often used in thin film solar cells, either as back contact or as hole transport layers. Secondary ion mass spectrometry (SIMS) was used to quantify the concentration of the species. A grain diffusion mechanistic model incorporating the …

Energy Harvesting Using Flextensional Piezoelectric Energy Harvesters In Resonance And Off-Resonance Modes, Mohamed A. Shabara

Mechanical & Aerospace Engineering Theses & Dissertations

Energy harvesting technologies are integrated into various modern devices and systems. These systems include Artificial Intelligence (AI) systems, Internet of Things (IoT), various types of energy harvesters are integrated in many engineering applications such as automotive, aerospace and ocean engineering. In order to develop a fully functioning stand-alone system, it is essential to integrate it with a built in power source such as a battery or a power generator. Also, in many situations, city power sources might not be available. Therefore, reliable, renewable and sustainable local power generators are desired. Piezoelectric energy harvesting (PEH) technologies, which are piezoelectric material-based devices, …

Validation Risk Across Hierarchical Models, John B. Young

Computational Modeling & Simulation Engineering Theses & Dissertations

Modeling and simulation are applied in a great many methods across a variety of topics. Model developers and users alike have a professional duty to understand the complexities of the tools and methods they are used. Oftentimes, models that have been independently constructed and executed are used to inform one another for an analytic purpose and the compatibility of the models is not always addressed. In the literature, great attention has been paid to model validation. When using models constructively with one another, analysts must understand the bounds of model validity and ensure that the combination of models does not …

Gesture Based Control Of Semi-Autonomous Vehicles, Brian Sanders

Computational Modeling & Simulation Engineering Theses & Dissertations

The objective of this investigation is to explore the use of hand gestures to control semi-autonomous vehicles, such as quadcopters, using realistic, physics based simulations. This involves identifying natural gestures to control basic functions of a vehicle, such as maneuvering and onboard equipment operation, and building simulations using the Unity game engine to investigate preferred use of those gestures. In addition to creating a realistic operating experience, human factors associated with limitations on physical hand motion and information management are also considered in the simulation development process. Testing with external participants using a recreational quadcopter simulation built in Unity was …

A Picture Is Worth A Thousand Roads, Keith Pierce

News Items

No abstract provided.

Modeling Energy Consumption Of High-Performance Applications On Heterogeneous Computing Platforms, Gary D. Lawson Jr.

Computational Modeling & Simulation Engineering Theses & Dissertations

Achieving Exascale computing is one of the current leading challenges in High Performance Computing (HPC). Obtaining this next level of performance will allow more complex simulations to be run on larger datasets and offer researchers better tools for data processing and analysis. In the dawn of Big Data, the need for supercomputers will only increase. However, these systems are costly to maintain because power is expensive. Thus, a better understanding of power and energy consumption is required such that future hardware can benefit.

Available power models accurately capture the relationship to the number of cores and clock-rate, however the relationship …

Diffusion Modeling Of Impurities Through The Molybdenum Back Contact Of Cigs Solar Cells, Chinedum John Akwari

Electrical & Computer Engineering Theses & Dissertations

CIGS is a major technology in photovoltaics and depends heavily, as any other PV technology, on the capacity to achieve the highest efficiency possible to compete on the market. Alkaline elements, notably sodium and potassium, play a key role in this matter as they enhance the open circuit voltage and the fill factor of the CIGS solar cells. However, this effect exists only for very specific concentration of sodium and potassium. These impurities typically diffuse through the soda-lime glass substrate.

Via modeling of the SIMS data, we try to understand and predict the diffusion mechanisms of these impurities from the …

Improved Ballistic Wind Prediction Using Projectile Tracking Data, William Arthur Kenney

Computational Modeling & Simulation Engineering Theses & Dissertations

The United States Air Force AC-130 gunships have been in operation since the Vietnam War and have seen frequent use during recent conflicts. They are able to employ gun weapon systems from above a target in a way that maximizes possible time on target. When firing, the gun operators must deal with miss distances caused by winds acting on the projectile in flight. Operators currently perform a “tweak” to predict a ballistic wind affecting fired rounds which is then used in the fire-control to correct for the real winds and bring shots onto target. This correction, a single-point wind prediction, …

The Effect Of Bone And Ligament Morphology Of Ankle Joint Loading In The Neutral Position, Jinhyuk Kim

Mechanical & Aerospace Engineering Theses & Dissertations

Computational modeling of joints is used to investigate the effect of injuries, to plan surgeries, and to answer questions about joints that cannot be answered experimentally. Existing models of the ankle joint are moving toward being able to model specific patients, however, they do not include all of the anatomy (e.g., bones and/or ligaments) and have restrictive boundary conditions. These simplification in anatomy are made to minimize pre-processing and computation time. Because biomechanical modeling is increasingly focused on the implementation of patient specific cases, the effects of including more anatomical structures and determining how they affect the model results is …

Water–Soil–Vegetation Dynamic Interactions In Changing Climate, Xixi Wang, Xuefeng Chu, Tingxi Liu, Xiangju Cheng, Rich Whittecar

Civil & Environmental Engineering Faculty Publications

Previous studies of land degradation, topsoil erosion, and hydrologic alteration typically focus on these subjects individually, missing important interrelationships among these important aspects of the Earth's system. However, an understanding of water–soil–vegetation dynamic interactions is needed to develop practical and effective solutions to sustain the globe's eco-environment and grassland agriculture, which depends on grasses, legumes, and other fodder or soil-building crops. This special issue is intended to be a platform for a discussion of the relevant scientific findings based on experimental and/or modeling studies. Its 12 peer-reviewed articles present data, novel analysis/modeling approaches, and convincing results of water–soil–vegetation interactions under …

Panic That Spreads Sociobehavioral Contagion In Pedestrian Evacuations, Terra Elzie, Erika Frydenlund, Andrew J. Collins, R. Michael Robinson

VMASC Publications

Crowds are a part of everyday public life, from stadiums and arenas to school hallways. Occasionally, pushing within the crowd spontaneously escalates to crushing behavior, resulting in injuries and even death. The rarity and unpredictability of these incidents provides few options to collect data for research on the prediction and prevention of hazardous emergent behaviors in crowds. This study takes a close look at the way states of agitation, such as panic, can spread through crowds. Group composition—mainly family groups composed of members with differing mobility levels—plays an important role in the spread of agitation through the crowd, ultimately affecting …

Detecting, Modeling, And Predicting User Temporal Intention, Hany M. Salaheldeen

Computer Science Theses & Dissertations

The content of social media has grown exponentially in the recent years and its role has evolved from narrating life events to actually shaping them. Unfortunately, content posted and shared in social networks is vulnerable and prone to loss or change, rendering the context associated with it (a tweet, post, status, or others) meaningless. There is an inherent value in maintaining the consistency of such social records as in some cases they take over the task of being the first draft of history as collections of these social posts narrate the pulse of the street during historic events, protest, riots, …

Toward A Theory Of Multi-Method Modeling And Simulation Approach, Mariusz A. Balaban

Computational Modeling & Simulation Engineering Theses & Dissertations

The representation via simulation models can easily lead to simulation models too simple for their intended purpose, or with too much detail, making them hard to understand. This problem is related to limitations of the modeling and simulation methods. A multi-method Modeling and Simulation (M&S) approach has the potential for improved representation by taking advantage of methods' strengths and mitigating their weaknesses. Despite a high appeal for using multiple M&S methods, several related problems should be addressed first. The current level of theoretical, methodological, and pragmatic knowledge related to a multi-method M&S approach is limited. It is problematic that there …

Fema Region Iii Coastal Flood Study - Hampton Roads Adaptation Forum, Robin Danforth

March 28, 2014: Addressing Current and Future Vulnerability through Floodplain Management

No abstract provided.

Engineering Collaborations In Medical Modeling And Simulation, Frederic D. Mckenzie, Salim Chemlal, Tom Hubbard, Robert E. Kelly, Roderick C. Borgie, David A. Besachio, Michel Audette

Computational Modeling & Simulation Engineering Faculty Publications

Fifty years ago computer science was just beginning to see common acceptance as a growing discipline and very few universities had a computer science department although other departments were utilizing computers and software to enhance their methodologies. We believe modeling and simulation (M&S) is on a similar path. Many other disciplines utilize M&S to enhance their methodologies but we also believe that M&S fundamentals can be essential in making better decisions by utilizing the appropriate model for the problem at hand, expanding the solution space through simulation, and understanding it through visualization and proper analyses. After our students learn these …

City Of Norfolk Coastal Flood Mitigation Program, Brian Joyner

March 13, 2013: Regional Sea Level Rise Assessment, Adaptation and Flood Mitigation Projects

No abstract provided.

Willoughby Spit Shoreline Improvement Project Of Ocean View Beach, Maura Boswell

March 13, 2013: Regional Sea Level Rise Assessment, Adaptation and Flood Mitigation Projects

No abstract provided.

Fema Region Iii Coastal Storm Surge Study, Mike Forte, Jeff Hanson, Michelle Hamor

March 13, 2013: Regional Sea Level Rise Assessment, Adaptation and Flood Mitigation Projects

No abstract provided.

Astronaut Eva Exposure Estimates From Cad Model Spacesuit Geometry, Giovanni De Angelis, Brooke M. Anderson, William Atwell, John E. Nealy, Gary D. Qualls, John W. Wilson

Mathematics & Statistics Faculty Publications

Ongoing assembly and maintenance activities at the International Space Station (ISS) require much more extravehicular activity (EVA) than did the earlier U.S. Space Shuttle missions. It is thus desirable to determine and analyze, and possibly foresee, as accurately as possible what radiation exposures crew members involved in EVAs will experience in order to minimize risks and to establish exposure limits that must not to be exceeded. A detailed CAD model of the U.S. Space Shuttle EVA Spacesuit, developed at NASA Langley Research Center (LaRC), is used to represent the directional shielding of an astronaut; it has detailed helmet and backpack …

Lunar Lava Tube Radiation Safety Analysis, Giovanni De Angelis, J. W. Wilson, M. S. Clowdsley, J. E. Nealy, D. H. Humes, J. M. Clem

Mathematics & Statistics Faculty Publications

For many years it has been suggested that lava tubes on the Moon could provide an ideal location for a manned lunar base, by providing shelter from various natural hazards, such as cosmic radiation, meteorites, micrometeoroids, and impact crater ejecta, and also providing a natural environmental control, with a nearly constant temperature, unlike that of the lunar surface showing extreme variation in its diurnal cycle. An analysis of radiation safety issues on lunar lava tubes has been performed by considering radiation from galactic cosmic rays (GCR) and Solar Particle Events (SPE) interacting with the lunar surface, modeled as a regolith …

A Method Of Modeling Multirate Two-Dimensional Recursive Digital Filters Author, Albert P. Gerheim

Electrical & Computer Engineering Theses & Dissertations

This dissertation presents a method of modeling two dimensional sampled data systems with two sampling rates in each dimension. This methodology is applied to the problem of synthesizing two dimensional velocity filters using one dimensional prototypes and multirate concepts.

The modeling method includes the replacement of scalar z-transforms of signals by vectors of polynomials, and the replacement of scalar z-transforms of impulse responses by matrices of polynomials.

The synthesis of velocity filters is accomplished through the use of coordinate transformations in the z-transform domain which skew the ω₁ -ω₂ axes on the unit bidisc. The filters synthesized using …