Digital Commons Network^™

A Novel Approach For Performance-Based Clustering And Management Of Network Traffic Flows, Muna Al-Saadi, Bogdan V. Ghita, Stavros Shiaeles, Panagiotis Sarigiannidis

School of Engineering, Computing and Mathematics

No abstract provided.

Nfv Resource Advertisement And Discovery Protocol For A Distributed Nfv Orchestration In A Wmn-Based Disaster Network, Gregor Frick, Auberlin Paguem Tchinda, Ulrich Trick, Armin Lehmann, Bogdan Ghita

School of Engineering, Computing and Mathematics

No abstract provided.

Enhancing Data Security In Cloud Using Random Pattern Fragmentation And A Distributed Nosql Database, Nelson L. Santos, Bogdan Ghita, Giovanni L. Masala

School of Engineering, Computing and Mathematics

No abstract provided.

Bandwidth Prediction Schemes For Defining Bitrate Levels In Sdn-Enabled Adaptive Streaming, Ali Edan Al-Issa, Abdelhak Bentaleb, Alcardo Alex Barakabitze, Thomas Zinner, Bogdan Ghita

School of Engineering, Computing and Mathematics

No abstract provided.

Modeling Cascading Failures In Power Systems In The Presence Of Uncertain Wind Generation, Mir Hadi Athari

Theses and Dissertations

One of the biggest threats to the power systems as critical infrastructures is large-scale blackouts resulting from cascading failures (CF) in the grid. The ongoing shift in energy portfolio due to ever-increasing penetration of renewable energy sources (RES) may drive the electric grid closer to its operational limits and introduce a large amount of uncertainty coming from their stochastic nature. One worrisome change is the increase in CFs.

The CF simulation models in the literature do not allow consideration of RES penetration in studying the grid vulnerability. In this dissertation, we have developed tools and models to evaluate the impact …

Load Scheduling With Maximum Demand And Time Of Use Pricing For Microgrids, Hayder O. Alwan

Theses and Dissertations

Several demand side management (DSM) techniques and algorithms have been used in the literature. These algorithms show that by adopting DSM and Time-of-Use (TOU) price tariffs; electricity cost significantly decreases, and optimal load scheduling is achieved. However, the purpose of the DSM is to not only lower the electricity cost, but also to avoid the peak load even if the electricity prices low. To address this concern, this dissertation starts with a brief literature review on the existing DSM algorithms and schemes. These algorithms can be suitable for Direct Load Control (DLC) schemes, Demand Response (DR), and load scheduling strategies. …

Perceived Impact Of Ambient Operating Room Noise By Certified Registered Nurse Anesthetists, Marianne S. Cosgrove

Theses and Dissertations

It is widely acknowledged that elevated levels of noise are commonplace in the healthcare environment, particularly in high acuity areas such as the operating room (OR). Excessive ambient noise may pose a threat to patient safety by adversely impacting provider performance and interfering with communication among perioperative care team members. With respect to the certified registered nurse anesthetist (CRNA), increased ambient OR noise may engender distractibility, diminish situation awareness and cause untoward health effects, thereby increasing the possibility for the occurrence of error and patient injury.

This research project analytically examines the perceived impact of ambient noise in the operating …

Towards Developing A Goal-Driven Data Integration Framework For Counter-Terrorism Analytics, Dapeng Liu

Theses and Dissertations

Terrorist attacks can cause massive casualties and severe property damage, resulting in terrorism crises surging across the world; accordingly, counter-terrorism analytics that take advantage of big data have been attracting increasing attention. The knowledge and clues essential for analyzing terrorist activities are often spread across heterogeneous data sources, which calls for an effective data integration solution. In this study, employing the goal definition template in the Goal-Question-Metric approach, we design and implement an automated goal-driven data integration framework for counter-terrorism analytics. The proposed design elicits and ontologizes an input user goal of counter-terrorism analytics; recognizes goal-relevant datasets; and addresses semantic …

Sensor Placement For Damage Localization In Sensor Networks, Fereshteh Firouzi

Theses and Dissertations

The objective of this thesis is to formulate and solve the sensor placement problem for damage localization in a sensor network. A Bayesian estimation problem is formulated with the time-of-flight (ToF) measurements. In this model, ToF of lamb waves, which are generated and received by piezoelectric sensors, is the total time for each wave to be transmitted, reflected by the target, and received by the sensor. The ToF of the scattered lamb wave has characteristic information about the target location. By using the measurement model and prior information, the target location is estimated in a centralized sensor network with a …

Engineering High Reaction Economy Or, An Intensification/Scoring Program For The Preparation Of Simple And Complex Molecules, Caleb J. Kong

Theses and Dissertations

Success of newly discovered chemistry in academia is often scored in terms of its novelty and level of scholarship. In industrial settings, cost, safety and quality are often times the ruler by which new processes are measured. Our group has identified that there is a gap between these two measures of success and has sought to develop principles in order formalize an approach to synthetic strategy and developing ready-to-implement manufacturing processes for molecules, simple and complex.

Some of these principles include (1) the development and application of new chemical methods and reactor technologies (2) recognition of globally amenable chemical environments …

Low Cost Graphene Oxide Aerogels For The Removal Of Pb+2 From Drinking Water, S Awan, J Bloor, D Jenkins, R Handy

School of Engineering, Computing and Mathematics

No abstract provided.

The Evaluation Of An Android Permission Management System Based On Crowdsourcing, Pulkit Rustgi

Theses and Dissertations

Mobile and web application security, particularly concerning the area of data privacy, has received much attention from the public in recent years. Most applications are installed without disclosing full information to users and clearly stating what they have access to. This often raises concerns when users become aware of unnecessary information being collected or stored. Unfortunately, most users have little to no technical knowledge in regard to what permissions should be granted and can only rely on their intuition and past experiences to make relatively uninformed decisions. DroidNet, a crowdsource based Android recommendation tool and framework, is a proposed avenue …

Modeling The Peak Absorption Of Meh-Ppv In Various Solvents Using Density Functional Theory, Corell H. Moore

Theses and Dissertations

Density Functional Theory (DFT) and time-dependent Density Functional Theory (TD-DFT) are powerful tools for modeling orbital energy in conjugated molecules and have been useful tools for research in organic photovoltaics. In this work, DFT is first used to explain the red shift in the absorption spectrum and increased absorption observed in MEH-PPV. Initially, the modeling of the red-shift in the absorption peak of MEH-PPV is studied using Gaussian 03 software with the global hybrid functional B3LYP for exchange-correlation and the 6-31G basis set. DFT and TD-DFT are used to separately study the effects of polymer chain length, carbon-carbon double-bond stretching, …

Fabrication Of Nanoporous Electrodes For Sensing Applications, Md Rezaul Karim Khan

Theses and Dissertations

Fabrication of nanoporous electrodes for sensing applications

By Md Rezaul Karim Khan, Ph.D.

A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University.

Virginia Commonwealth University, 2019. Major Director: Dr. Maryanne M. Collinson

Professor of Chemistry

The focus of this dissertation work is the fabrication of nanoporous electrodes and the study of their chemical and physical properties. The fabrication routes involved one or more of the following strategies: dealloying or chemical corrosion, co-electrodeposition, physical vapor deposition, and metal ions reduction. The work was not only restricted to the synthesis of …

Electrostatic Networks And Mechanisms Of Δph-Dependent Gating In The Human Voltage-Gated Proton Channel Hv1, Ashley L. Bennett

Theses and Dissertations

The structure of the voltage-gated proton (H⁺) channel Hv1 is homologous to the voltage sensor domain (VSD) of tetrameric voltage-gated Na⁺, K⁺ and Ca²⁺ channels (VGCs), but lacks a pore domain and instead forms a homodimer. Similar to other VSD proteins, Hv1 is gated by changes in membrane potential (V), but unlike VGCs, voltage-dependent gating in Hv1 is modulated by changes in the transmembrane pH gradient (DpH = pH_o - pH_i). In Hv1, pH_o or pH_i changes shift the open probability (P_OPEN)-V relation by ~40 mV per …

Mathematics Identity Construction In Successful African Americans: Reflections On Mathematics Experiences During Adolescence, Teri N. Johnson

Theses and Dissertations

This project used narrative inquiry to examine adolescent experiences that contributed to the development of positive mathematics identities in successful African Americans. Ten African Americans, who had worked in a STEM-related occupation for at least two years, were asked to reflect on in- and out-of-school experiences with mathematics during their middle and high school years. Data collection included individual interviews and one focus group discussion. A combination of internal and external factors emerged as contributors to participants’ adolescent mathematics identities. Internal factors included early career interest, finding enjoyment in the challenges associated with learning mathematics, or facing setbacks they were …

Cold X-Ray Effects On Satellite Solar Panels In Orbit, Myles Fogleman

Theses and Dissertations

An exo-atmospheric nuclear detonation releases up to 80 percent of its’ energy as X-rays. Satellite’s solar cells and their protective coatings are vulnerable to low energy X-ray radiation. Cold X-rays (~1-1.5 keV) are absorbed close to the surface of materials causing the blow-off and rapid formation of Warm Dense Plasmas (WDPs), particularly in a gap between the unshielded active elements of solar cells. To understand how WDPs are created, it is necessary to investigate the power density distribution produced by cold X-rays for typical solar panel surface materials. The Monte Carlo stepping model implemented in the GEANT4 software toolkit is …

Planting Density Effects On The Growth Of Dune Grasses., Audrey Kirschner

Theses and Dissertations

Coastal dune vegetation plays a key role in dune formation and stabilization through sediment trapping and erosion control. To restore degraded dunes, revegetation of dune building species is critical. Planting density has been found to effect growth of marsh species, with closer plantings alleviating stress through facilitation. As coastal dunes are high stress environments, it is expected that dune species may also exhibit facilitative interactions based on the Stress Gradient Hypothesis. Therefore, planting grasses in clumped configurations may lead to more successful dune revegetation. The objective of this research was to determine how planting density affects the growth of two …

Assessing The Quality Of Software Development Tutorials Available On The Web, Manziba A. Nishi

Theses and Dissertations

Both expert and novice software developers frequently access software development resources available on the Web in order to lookup or learn new APIs, tools and techniques. Software quality is affected negatively when developers fail to find high-quality information relevant to their problem. While there is a substantial amount of freely available resources that can be accessed online, some of the available resources contain information that suffers from error proneness, copyright infringement, security concerns, and incompatible versions. Use of such toxic information can have a strong negative effect on developer’s efficacy. This dissertation focuses specifically on software tutorials, aiming to automatically …

Effects Of Geometry And Phase On Material Damage Response Under High-Speed Impact, Rachel Waxman

Theses and Dissertations

Peridynamics, presented by Silling in 2000 [1], is a reformulation of the elastic theory from differential equations to integral equations, which are more equipped to handle discontinuities, such as crack initiation and propagation. Because of this, peridynamics is an effective tool to address many of the problems relevant to the aerospace and defense industries. For example, airborne sand particles and raindrops cause local damage to aircraft in flight. This damage manifests itself as radial and subsurface lateral cracking, as well as increased surface roughness. All of these damage morphologies may result in undesired degradation of mechanical and optical properties.

This …

Optimizing Nasal Cannulas For Infants Using Computational Fluid Dynamics, Ahmad El-Achwah Mr.

Theses and Dissertations

Aerosolized medications can potentially be delivered to the lungs of infants through a nasal cannula interface. However, nose-to-lung delivery technologies currently allow for ~1% of the loaded dose to reach an infant’s lungs. Conventional dry powder inhalers (DPI) are superior to other types of inhalers in many ways. However, passive DPIs that operate based on user inhalation and require large volumes of airflow are not applicable to infants. To overcome this challenge, positive pressure DPIs have been developed that enable aerosol delivery to infants. Unless an adequate nasal interface is used with these devices, a significant amount of drug will …

Explainable Neural Networks Based Anomaly Detection For Cyber-Physical Systems, Kasun Amarasinghe

Theses and Dissertations

Cyber-Physical Systems (CPSs) are the core of modern critical infrastructure (e.g. power-grids) and securing them is of paramount importance. Anomaly detection in data is crucial for CPS security. While Artificial Neural Networks (ANNs) are strong candidates for the task, they are seldom deployed in safety-critical domains due to the perception that ANNs are black-boxes. Therefore, to leverage ANNs in CPSs, cracking open the black box through explanation is essential.

The main objective of this dissertation is developing explainable ANN-based Anomaly Detection Systems for Cyber-Physical Systems (CP-ADS). The main objective was broken down into three sub-objectives: 1) Identifying key-requirements that an …

Assessment Of Access Methods For Mobile Maps For Individuals Who Are Blind Or Visually Impaired, David Parker

Theses and Dissertations

When people go to a mall, museums, or other such locations they tend to rely on maps to find their way around. However, for people who are blind or visually impaired (BVI) maps are not easily accessible and they depend on other means, such as a guide, to get around. Research has only just begun to investigate providing maps for people who are BVI on touch screen devices. Many different types of feedback have been used: audio (sound), tactile (touch), audio-tactile, and multitouch. Some research has been conducted on the benefit of using multiple fingers (multitouch) and has found conflicting …

Engineering Of Earth-Abundant Electrochemical Catalysts, Dylan D. Rodene

Theses and Dissertations

Alternative energy research into hydrogen production via water electrolysis addresses environmental and sustainability concerns associated with fossil fuel use. Renewable-powered electrolyzers are foreseen to produce hydrogen if energy and cost requirements are achieved. Electrocatalysts reduce the energy requirements of operating electrolyzers by lowering the reaction kinetics at the electrodes. Platinum group metals (PGMs) tend to be utilized as electrocatalysts but are not readily available and are expensive. Ni_1-xMo_x alloys, as low-cost and earth-abundant transition metal nanoparticles (NPs), are emerging as promising electrocatalyst candidates to replace expensive PGM catalysts in alkaline media. Pure-phase cubic and hexagonal Ni_{1-x …}

“We’Re Trying To Have A Childhood”: Parent Notions Of Kindergarten Readiness, Isabel F. Johnson

All Theses And Dissertations

In response to the chronic third-grade achievement-gap, public school kindergartens have abandoned Froëbel’s traditional child-centered pedagogy in favor of an early academic preparation model that promotes the idea of kindergarten readiness. But top-down implementation of readiness curriculum has not led to sustainable gains and may result in poorer student outcomes. The bioecological repercussions of early academic expectations on young children and their families are not well understood, and parent perspectives on the topic are often marginalized. This qualitative case study explored parent notions of kindergarten readiness using word coding analysis of eight kindergarten and preschool parent interviews. Findings from thematic …

An Improved Prediction Of The Effective Range Of Stress Intensity Factor In Fatigue Crack Growth, B Yang, Mn James, Y Huang, Jm Vasco-Olmo, Fa Díaz

School of Engineering, Computing and Mathematics

No abstract provided.

Towards Simulated Morality Systems: Role-Playing Games As Artificial Societies, J Casas-Roma, M Nelson, J Arnedo-Moreno, S Gaudl, R Saunders

School of Engineering, Computing and Mathematics

No abstract provided.

Towards Generating Spatial Referring Expressions In A Social Robot: Dynamic Vs Non-Ambiguous, Cd Wallbridge, S Lemaignan, E Senft, T Belpaeme

School of Engineering, Computing and Mathematics

No abstract provided.

Second Language Tutoring Using Social Robots: A Large-Scale Study, P Vogt, Den Berghe R Van, Haas M De, L Hoffman, J Kanero, E Mamus, J-M Montanier, C Oranc, O Oudgenoeg-Paz, Dh Garcia, F Papadopoulos, T Schodde, J Verhagen, Cd Wallbridgell, B Willemsen, Wit J De, T Belpaeme, T Goksun, S Kopp, E Krahmer, Ac Kuntay, P Leseman, Ak Pandey

School of Engineering, Computing and Mathematics

We present a large-scale study of a series of seven lessons designed to help young children learn English vocabulary as a foreign language using a social robot. The experiment was designed to investigate 1) the effectiveness of a social robot teaching children new words over the course of multiple interactions (supported by a tablet), 2) the added benefit of a robot's iconic gestures on word learning and retention, and 3) the effect of learning from a robot tutor accompanied by a tablet versus learning from a tablet application alone. For reasons of transparency, the research questions, hypotheses and methods were …

Understanding The Relation Between Zika Virus Infection During Pregnancy And Adverse Fetal, Infant And Child Outcomes: A Protocol For A Systematic Review And Individual Participant Data Meta-Analysis Of Longitudinal Studies Of Pregnant Women And Their Infants And Children, Annelies Wilder-Smith, Yinghui Wei, Thalia Velho Barreto De Araújo, Maria Vankerkhove, Marília Dalva Turchi, Marília Dalva Turchi, Mauro Teixeira, Adriana Tami, João Souza, Patricia Sousa, Antoni Soriano-Arandes, Carmen Soria-Segarra, Clemente N Sanchez, Kerstin Daniela Rosenberger, Ludovic Reveiz, Arnaldo Prata-Barbosa, Léo Pomar, Rosado Le Pelá, Freddy Perez, Saulo D. Passos, Mauricio Nogueira, Trevor P. Noel, Da Silva A Moura, Maria Elisabeth Moreira, Ivonne Morales, Montoya Mc Miranda, Demócrito De Barros Miranda-Filho, Lauren Maxwell, Calum N.L. Macpherson, Nicola Low, Zhiyi Lan, Angelle Desiree Labeaud, Marion Koopmans, Caron Kim, Esaú João, Thomas Jaenisch, Cristina Barroso Hofer, Paul Gustafson, Patrick Gérardin, Jucelia S. Ganz, Ana Carolina Fialho Dias, Vanessa Elias, Geraldo Duarte, Thomas Paul Alfons Debray, María Luisa Cafferata, Pierre Buekens, Nathalie Broutet, Elizabeth B. Brickley, Patrícia Brasil, Fátima Brant, Sarah Bethencourt, Andrea Benedetti, Vivian Lida Avelino-Silva, Ricardo Arraes De Alencar Ximenes, Da Cunha A Alves, Jackeline Alger

School of Engineering, Computing and Mathematics

IntroductionZika virus (ZIKV) infection during pregnancy is a known cause of microcephaly and other congenital and developmental anomalies. In the absence of a ZIKV vaccine or prophylactics, principal investigators (PIs) and international leaders in ZIKV research have formed the ZIKV Individual Participant Data (IPD) Consortium to identify, collect and synthesise IPD from longitudinal studies of pregnant women that measure ZIKV infection during pregnancy and fetal, infant or child outcomes.Methods and analysisWe will identify eligible studies through the ZIKV IPD Consortium membership and a systematic review and invite study PIs to participate in the IPD meta-analysis (IPD-MA). We will use the …