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

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

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

Open Textbooks

More than 50 freely available and openly licensed textbooks are among our most downloaded items.


Recent Submissions

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Demonstration of chemotherapeutic-mediated changes in meningeal lymphatics in vitro, ex vivo, and in vivo
Roberts, L. Monet; Hammel, Jennifer H.; Peng, Jin; Cunningham, Jessica J.; Schumaecker, Sophia; Davis, Skylar; Azar, Francesca; Alkaid Feng, Tzu-Yu; Wang, Maosen; Rutkowski, Melanie; Munson, Jennifer M. (Nature Research, 2025-10-13)
Systemic chemotherapy often affects cells beyond the tumor, raising concerns about their impact on peripheral tissues, including the central nervous system (CNS). The meningeal lymphatics drain cerebrospinal fluid from the CNS to the deep cervical lymph nodes, assisting in immunosurveillance and linking theCNSto the periphery. They have been implicated in a number of brain-related disorders with disruption exacerbating cognitive deficits. However, in vivo, distinguishing between direct and indirect effects of systemic chemotherapy on the meningeal lymphatics remains highly challenging, making it difficult to isolate specific impact on the CNS. To address this, we present two models we have developed that allow the examination of cellular and tissue-level changes to study the effects of systemic chemotherapy on the meningeal lymphatics. Our in vitro tissue engineered model representative of a meningeal lymphatic vessel lumen shows cell disruption, while our ex vivo model culturing mouse meningeal layers probes structural changes in a controlled setting. Finally, we correlate functional outcomes with observed changes in vivo and show that systemic taxane chemotherapy leads to morphological changes in the meningeal lymphatics, a trend of reduced flow through the brain, and impaired cognition, emphasizing the need for further study of off-target impacts in the CNS and the value of multi-model approaches.
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Discovering Heuristics with Large Language Models (LLMs) for Mixed-Integer Programs: Single-Machine Scheduling
Cetinkaya, Ibrahim; Büyüktahtakın, İ. Esra; Shojaee, Parshin; Reddy, Chandan K. (2025-10-14)
Our study contributes to the scheduling and combinatorial optimization literature with new heuristics discovered by leveraging the power of Large Language Models (LLMs). We focus on the single-machine total tardiness (SMTT) problem, which aims to minimize total tardiness by sequencing n jobs on a single processor without preemption, given processing times and due dates. We develop and benchmark two novel LLM-discovered heuristics, the EDD Challenger (EDDC) and MDD Challenger (MDDC), inspired by the well-known Earliest Due Date (EDD) and Modified Due Date (MDD) rules. In contrast to prior studies that employed simpler rule-based heuristics, we evaluate our LLM-discovered algorithms using rigorous criteria, including optimality gaps and solution time derived from a mixed-integer programming (MIP) formulation of SMTT. We compare their performance against state-of-the-art heuristics and exact methods across various job sizes (20, 100, 200, and 500 jobs). For instances with more than 100 jobs, exact methods such as MIP and dynamic programming become computationally intractable. Up to 500 jobs, EDDC improves upon the classic EDD rule and another widely used algorithm in the literature. MDDC consistently outperforms traditional heuristics and remains competitive with exact approaches, particularly on larger and more complex instances. This study shows that human–LLM collaboration can produce scalable, high-performing heuristics for NP-hard constrained combinatorial optimization, even under limited resources when effectively configured.
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Water in the 2024 Virginia General Assembly
Raflo, Alan (Virginia Water Resources Research Center, 2024)
In the tables below (starting on page 2), the Virginia Water Resources Research Center lists 151 measures in the 2024 Assembly dealing with water resources. The bills may affect water directly, such as bills on fishery management, water and sewer systems, or water quality standards; or indirectly by dealing with land uses, energy uses, or energy production, all of which can affect aquatic habitat, water use, water pollution, or climate-change impacts. The list also includes the Budget Bills, which have major effects on water through funding of water-related agencies, as well as occasionally through policy statements approved during the budget process.
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Water in the 2023 Virginia General Assembly
Raflo, Alan (Virginia Water Resources Research Center, 2023)
In the tables below (starting on page 2), the Virginia Water Resources Research Center lists 135 measures in the 2023 Assembly dealing with water resources directly or indirectly, including two budget bills amending the current state budget that runs through June 30, 2024. The 2023 General Assembly convened on January 11 and adjourned on February 25. This was a so-called “short session,” which is held in all odd-numbered years. “Long sessions” of 60 days are held in even- numbered years. A reconvened (“veto”) session A reconvened (“veto”) session, for the purpose of considering vetoes or recommendations from the governor, was held on April 12. During long sessions, the Commonwealth’s budget for the upcoming two years is set; amendments to the current biennial budget may be considered both in short and long sessions.
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Water in the 2022 Virginia General Assembly
Raflo, Alan (Virginia Water Resources Research Center, 2022)
In the tables below (starting on page 2), the Virginia Water Resources Research Center lists 156 measures in the 2022 Assembly dealing with water resources directly or indirectly, including bills related to the current biennial budget (through June 30, 2022) and the proposed budget for the 2022-2024 biennium. The 2022 General Assembly convened on January 12 and adjourned on March 12. On March 23, Gov. Glenn Younkin called back the Assembly for a special session to begin on April 4 for the purpose of passing a biennial state budget for fiscal years 2023 and 2024; the governor’s proclamation calling back the Assembly is online at this link (as of 5-17-22). As of 5-17-22, a biennial budget had not been passed and the General Assembly was still officially in special session. A reconvened (“veto”) session, for the purpose of considering vetoes or recommendations from the governor, was held on April 27, 2022. More information about the Assembly’s normal schedule and duration is available in “About the General Assembly,” online at this link. The General Assembly’s main Web page, http://virginiageneralassembly.gov/index.php, offers several useful features, including member lists, session calendars, live video of floor sessions, and information on legislative processes. The Legislative Information System (LIS) Web site, http://lis.virginia.gov/lis.htm (also at http://leg1.state.va.us), provides lists and summaries of all bills, searchable by topic, member, committee, etc.