VTechWorks
VTechWorks provides global access to Virginia Tech scholarship, including journal articles, books, theses, dissertations, conference papers, slide presentations, technical reports, working papers, administrative documents, videos, images, and more by faculty, students, and staff. Faculty can deposit items to VTechWorks from Elements, including journal articles covered by the University open access policy. Email vtechworks@vt.edu for help.
Open Access Policy
Virginia Tech's open access policy enables researchers to deposit the accepted version of scholarly articles with no embargo.
Theses and Dissertations
Virginia Tech was first in the world to require ETDs in 1997, and continues to add scans of older theses and dissertations.
Open Textbooks
More than 50 freely available and openly licensed textbooks are among our most downloaded items.
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Recent Submissions
Eyes on the Road! – A Market Assessment Investigating the Characteristics, Capabilities, and Limitations of Production Head-Up Displays
Walters, Jacob; Anderson, Gabrial T. (National Surface Transportation Safety Center for Excellence, 2026-11-11)
This report provides a structured descriptive assessment of head-up display (HUD) implementations and availability across the 2025 U.S. light-vehicle market. It combines a broad market scan with a smaller comparative review of vehicles for which sufficiently detailed materials were publicly available, with the goal of identifying common implementation patterns, documented differences, and recurring design tendencies.
At the market level, the evidence collected indicates that HUDs are now an established premium-to-upper-mainstream feature, but they are still more often used as an equipment differentiator than as a universally standard interface. Within the 20-vehicle review sample, availability was most often tied to trim level, while package-based or add-on pathways were less common. Across the reviewed vehicles, manufacturers overwhelmingly described forward-view, windshield-oriented HUD systems. In practice, this suggests convergence on a common display architecture, with most differentiation occurring in packaging, size, displayed content, color treatment, and adjustment logic rather than in projection concept.
Taken as a whole, the reviewed materials point toward a consistent interpretation of current HUD strategy. Across the sample, the HUD is typically positioned as a forward-view driver-information surface for glanceable, high-priority content and is also used as a usability feature and trim-level differentiator. The evidence in this report does not support a claim of full market uniformity, but it does support the narrower conclusion that recent differentiation is concentrated less in basic projection architecture than in packaging, interface tuning, content mix, and presentation detail.
Fleet Automation: Introducing Automated Driving Technologies to Fleets
Miller, Andrew M.; Britten, Nicholas; Pugliese, Brian (National Surface Transportation Safety Center for Excellence, 2026-11-11)
This research, funded by stakeholders of the National Surface Transportation Safety Center for Excellence (NSTSCE), investigates practical methods for analyzing the integration of Automated Driving Systems (ADS) into commercial vehicle operations (CVOs). Given the complexity of integrating automated technology into trucking fleets, the project applied a hybrid approach combining hierarchical task analysis (HTA), cognitive work analysis (CWA), and contextual inquiry (CI) methodologies to assess operational tasks, workflows, and human factors considerations within a controlled intermodal port environment.
Through extensive site evaluations, interviews, operational mapping, macrocognitive analysis, and Human Reliability Analysis (HRA), the research team identified critical tasks, risks, personnel interactions, and organizational dynamics relevant to ADS implementation. The findings highlighted critical fleet characteristics, such as fleet size, operational complexity, cargo type, and environmental factors, essential for successful ADS integration.
Building upon these insights, the project developed the Automation Implementation Strategies (AIS) tool—a web-based Qualtrics survey that provides a decision-support framework designed for CVOs. The AIS tool provides fleet management with tailored automation recommendations based on four primary areas: fleet operations, localization strategies, automation system behaviors, and human-in-the-loop considerations.
The AIS tool developed in this project emphasizes accessibility and scalability for fleets of all sizes. While large carriers have traditionally partnered with ADS developers, small and midsize fleets often lack the resources to assess automation readiness. The AIS tool addresses this gap by translating complex systems analysis into actionable, context-sensitive recommendations. By enabling fleets to self-assess and explore viable automation pathways, the tool supports broader industry adoption, promotes equity in access to innovation, and contributes to national goals for transportation safety and efficiency.
AI-Powered Weather Detection System for Enhanced Roadway Safety
Thapa, Surendra Bikram; Sarkar, Abhijit (National Surface Transportation Safety Center for Excellence, 2026-11-11)
This study investigates the use of large vision-language models (LVLMs) as a flexible alternative for environmental perception. LVLMs enable image understanding through natural language prompting, reducing the need for task-specific model development. We conducted a comprehensive analysis using the RWVC-BDD dataset, a manually annotated subset of BDD100K with labels for road condition, weather, and visibility. The study examines three modeling paradigms: (1) direct end-to-end LVLM prediction, (2) task-specific concept-based modeling using LVLM-extracted features with classical machine learning classifiers, and (3) combined cross-domain concept modeling that integrates cues across tasks.
Results show that direct LVLM predictions provide a reasonable baseline, particularly for weather classification, but exhibit limitations for more complex tasks such as road condition and visibility, where class imbalance and subtle visual cues reduce reliability. Task-specific concept modeling improves visibility performance and enhances class balance for road condition, demonstrating that structured intermediate representations can stabilize predictions. However, it may reduce performance for tasks requiring holistic scene understanding. The strongest improvement is observed with combined concept modeling, which consistently outperforms both prior approaches and achieves substantial gains in performance across all tasks.
To assess real-world applicability, the framework was further evaluated using traffic camera data from the Virginia Department of Transportation 511 system. Results show strong performance across tasks, particularly under combined concept modeling, highlighting the potential of the approach for infrastructure-based applications such as roadway condition monitoring and weather-aware analysis. Overall, this study demonstrates that LVLMs, when combined with structured concept representations and cross-domain feature integration, provide a promising and scalable framework for environmental perception in transportation systems. The approach reduces engineering overhead, improves interpretability, and enhances performance, making it well-suited for rapid experimentation and deployment in safety-critical applications.
Targeted Modulation of Immune Signaling Pathways in Systemic Lupus Erythematosus
Montano, Hilary (Virginia Tech, 2026-11-10)
Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by hyperactive B cell activity leading to production of autoantibodies and aberrant cytokine signaling. In this dissertation, we focused on improving our understanding of the role of protein signaling pathways in SLE. We modified disease by targeting the adenosine receptor and through germline deletion of targeting the NIK protein. For our adenosine receptor studies, we utilized NZB/W F1 female lupus mice. As these mice develop clinical manifestations of lupus at about 23 weeks-of-age, we injected the mice with an Adenosine 2A Receptor (A2AR) agonist and an Adenosine 2B Receptor (A2BR) antagonist from 21-weeks-of-age to 34-weeks-of-age to determine if modification of the adenosine receptor subtypes would decrease disease severity. Overall, we found that the A2BR antagonist (ADO-5024) was able to improve various disease-associated parameters in these mice, including prolonging survival, while decreasing proteinuria, C3 renal deposition, autoantibody production, and inflammatory cytokine secretion, to be comparable to the standard treatment, dexamethasone. On the other hand, the A2AR agonist, ADO-6001, failed to reduce lupus disease. Treatment with the A2AR agonist, ADO-6001 resulted in disease parameters that were not significantly different from our negative controls. Significantly, ADO-5024 resulted in reduced plasma cell abundance and autoantibody production, demonstrating an important autoimmune role for this signaling pathway.
Using MRL/lpr lupus mice, we targeted the map3k14 gene. We found that Map3k14 deletion on the MRL/lpr background identified contrasting roles for the gene encoding for NIK in systemic immunity vs tissue inflammation. NIK is the master regulator for the non-canonical NF-B pathway which is responsible for many immunoregulatory roles. Although map3k14 KO mice rapidly deteriorated compared to their wild type and heterozygous counterparts, autoantibodies were reduced along with type 2 conventional dendritic cells (cDC2), T helper cells and their subsets, and cytokines like CCL2 and IL-5. However, there was a significant increase of C3, IgG, and SiglecF deposition into the renal tissue leading to elevated proteinuria and reduced renal function. The findings presented in this dissertation will provide a foundation to further examine the role of NIK in immune specific cell populations as NIK may have differential roles on immune cell function. Understanding cell specific pathways regarding NIK function may lead to development of more selective therapeutics for the treatment of SLE.
Antimicrobial Resistance in Livestock Systems: Resistome Ecology, Bacterial Genomics, and Antimicrobial Stewardship
Odur, Ivan Oluk (Virginia Tech, 2026-11-10)
Antimicrobial resistance (AMR) is a complex One Health challenge shaped by interactions among microorganisms, food-producing animals, agricultural environments, and antimicrobial use practices. Livestock systems can serve as reservoirs of antimicrobial-resistant bacteria and antimicrobial resistance genes (ARGs), yet the ecological factors shaping these reservoirs, the bacterial hosts carrying resistance determinants, and the human practices influencing antimicrobial use remain incompletely understood. This dissertation examines AMR across livestock systems through complementary ecological, genomic, environmental, and behavioral approaches. Chapters 2 through 5 characterize: (1) resistome ecology in sheep and goat fecal microbiomes, (2) phenotypic and genomic characteristics of Escherichia coli from small ruminants and their relationship to E. coli from other host sources, (3) antimicrobial use knowledge, attitudes, practices, and stewardship among small ruminant farmers and veterinarians, and (4) antimicrobial resistance and genomic diversity among airborne Staphylococcus associated with swine and dairy environments.
Chapter 2 characterized fecal microbiomes and resistomes of 46 sheep and goats originating from 16 farms using shotgun metagenomic sequencing. Twenty-eight antimicrobial resistance classes were identified, with tetracycline and β-lactam resistance determinants comprising the largest proportions of the resistome and blaTEM, tetQ, and tetW among the most abundant genes. ARG richness, Shannon diversity, and resistome composition did not differ significantly between sheep- and goat-associated farm-level groups. However, ecological resistome risk differed significantly among farms, whereas human health resistome risk showed weaker farm-level variation. Animal species had no detectable effect after accounting for farm structure. Analysis of ARGs and mobile genetic elements further identified extensive genomic co-occurrence between resistance-associated and mobility-associated annotations, particularly those related to transfer. These findings highlight the importance of farm-level ecological factors and mobile genetic context when evaluating AMR reservoirs in understudied small ruminant production systems.
Chapter 3 examined phenotypic antimicrobial resistance and genomic characteristics of 27 E. coli isolates recovered from sheep and goats. Resistance was observed to multiple antimicrobial classes, and 29.6% of isolates exhibited multidrug-resistant phenotypes. Whole-genome sequencing revealed substantial genomic diversity, including 20 multilocus sequence types among 26 typeable isolates, and identified combinations of antimicrobial resistance, metal- and biocide-resistance, virulence, and mobile genetic element-associated determinants. Notable isolates included a LEE-negative Shiga toxin-producing E. coli carrying stx2, subAB, iha, lpfA-O113, and tellurite-resistance determinants, as well as isolates carrying ColV-like virulence-associated features. The 27 study isolates were further compared with 56 quality-selected publicly available E. coli genomes from cattle, swine, poultry, and human sources, producing an 83-genome comparative dataset. AMR determinant richness and composition differed among host groups, with sheep- and goat-associated isolates generally carrying fewer ARGs than cattle-, swine-, and human-associated isolates. These findings demonstrate that small ruminants harbor genetically diverse E. coli, including strains carrying combinations of resistance, virulence, stress-response, and potentially mobile determinants relevant to One Health surveillance.
Chapter 4 evaluated antimicrobial-use practices, AMR knowledge, perceptions, and stewardship behaviors among small ruminant farmers and veterinarians in Virginia. Forty-eight farmers and eight veterinarians completed the respective surveys. Both groups generally demonstrated strong awareness of AMR and support for responsible antimicrobial use; however, important gaps remained between knowledge and practice. Although most farmers reported maintaining a valid veterinarian-client-patient relationship, veterinary consultation before administering antibiotics was not always routine, and greater livestock-raising experience was associated with substantially lower odds of routine veterinary consultation. Additional gaps included inconsistent record-keeping and limited application of withdrawal period knowledge. Veterinarians demonstrated high stewardship and regulatory awareness but identified practical barriers to optimal antimicrobial use, including producer engagement, economic constraints, and limitations in diagnostic infrastructure. These findings suggest that stewardship challenges in small ruminant systems are shaped not only by knowledge but also by behavioral, experiential, and structural factors, emphasizing the importance of strengthening active veterinarian-producer relationships.
Chapter 5 characterized antimicrobial resistance, stress-resistance determinants, and plasmid-associated genomic features among airborne Staphylococcus cohnii and Staphylococcus haemolyticus recovered from swine- and dairy-associated environments. Whole-genome analyses included 108 bioaerosol S. cohnii and 12 bioaerosol S. haemolyticus isolates together with phylogenetically related publicly available genomes. Among S. cohnii, ARG richness and composition were broadly similar between bioaerosol and selected public genomes, whereas the disinfectant-associated determinant qacG and cadmium-resistance determinant cadD were strongly enriched among bioaerosol genomes. In contrast, ARG composition differed substantially between bioaerosol and public S. haemolyticus genomes, with several resistance determinants enriched in each dataset. The stress-resistance determinant qacG was also enriched among bioaerosol S. haemolyticus, and plasmid-replicon composition differed between datasets. Same-contig associations among plasmid replicons, ARGs, and stress-resistance determinants further identified genomic contexts consistent with potential physical linkage, although these associations do not demonstrate horizontal transfer. These findings extend livestock bioaerosol AMR research from gene detection to viable bacterial hosts and highlight non-aureus Staphylococcus as potential reservoirs of resistance- and stress-associated determinants in agricultural environments.