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SysOptiMaL Research

Come and join the cutting-edge world of research with Dr. Büyüktahtakιn Toy and the Systems Optimization and Machine Learning Lab (SysOptiMaL). We are solving real-world problems that need to be solved quickly and at a superb quality through advancing multi-stage stochastic combinatorial optimization with a combination of theory and algorithms. Our ongoing exploration delves into deep machine learning and AI algorithms, predicting optimal solutions for optimization problems under uncertainty. At SysOptiMaL, we tackle real-world challenges in security, healthcare, agriculture, environment, and more. We use data analytics, AI, and optimization techniques to create strategies that boost efficiency and sustainability under limited resources.
Our lab has earned prestigious funding with a total of $2.5M from organizations such as the NSF CAREER Award, NSF, USDA, US Forest Service, and the U.S. Office of Naval Research. If you are passionate about advancing research, we invite you to apply to Virginia Tech's ISE Ph.D. program. Please do not hesitate to reach out to Dr. Esra Buyuktahtakin Toy at esratoy@vt.edu with your CV and application materials. Explore the exciting opportunity of becoming a Graduate Assistant with us. Let's perform groundbreaking research, contribute to the scientific community by writing influential papers, and shape the future together at SysOptiMaL!

In SysOptimal, we develop integrated optimization and machine learning approaches to address challenging research problems in complex systems by a mix of theoretical and computational analysis.

Of particular interests are:

Methodology

Optimization under Uncertainty
Risk-Averse Stochastic Mixed-Integer Programming
Machine Learning
Reinforcement Learning
Integrated Optimization and Data Analytical Methods
Computational Optimization
Mathematical Biology

Applications

Spatio-temporal Resource Allocation to Survey and Control Biological Invasions: Invasive Species, Epidemics, and Cancer
Resource allocation for Controlling COVID-19
Emerald Ash Borer treatment planning to protect Urban Forests
Ebola Outbreak Treatment Center Location and Resources Planning
3D Cancer Growth Modeling and Cancer Treatment Planning
Supply Chain Management, Production Planning and Logistics

Funding Awards and Projects
Principle Investigator (PI), U.S. Forest Service Grant Contract, “Risk-Averse Surveillance and Intervention Planning for Emerald Ash Borer in Community Forests-Modification,” U.S. Forest Service Northern Research Station. St. Paul, MN, 06/23/2022–5/31/2023, $134,485 (co-PIs–Dr. Wenbo Cai from MIE NJIT and Dr. Robert Haight from U.S. Forest Service)
Principle Investigator (PI), U.S. Forest Service Grant Contract, “Optimizing public-private partnership under a limited budget and heterogeneous participants: a game-theoretic optimization approach to EAB management,” U.S. Forest Service Northern Research Station. St. Paul, MN, 04/26/2021–12/31/2023, $97,476 (co-PIs–Dr. Wenbo Cai from MIE NJIT and Dr. Robert Haight from U.S. Forest Service)
Principle Investigator (PI), NSF CAREER Award CBET #1554018, “CAREER: Dynamic Invasive Species Control Optimization Via Integrated Education and Research (DISCOVER),” National Science Foundation (co-funded by the CBET/ENG Environmental Sustainability program and the Division of Mathematical Sciences in MPS/NSF), 03/01/16–02/28/21, $500,000.
PI, U.S. Forest Service Grant Contract, “Risk-Averse Surveillance and Intervention Planning for Emerald Ash Borer in Community Forests,” U.S. Forest Service Northern Research Station. St. Paul, MN, 07/01/2018–07/30/2021, $58,142 (co-PI–Dr. Robert Haight from U.S. Forest Service)
Co-PI, United States Department of Agriculture (USDA) Grant Award, “Integrating Modeling and Field Experiments to Guide Weed Management in Rangeland Systems,” USDA Agriculture and Food Research Initiative (AFRI), 03/01/2016– 02/28/2021, $430,000 (PI–Dr. Houseman from Department of Biological Sciences, WSU).
Principle Investigator (PI), U.S. Forest Service Grant Contract, “A Principal-Agent Game Theoretical Model for Intervention Planning of Emerald Ash Borer in Public and Private Forests,” U.S. Forest Service Northern Research Station. St. Paul, MN, 05/10/2019–12/31/2020, $61,186 (co-PIs–Dr. Wenbo Cai from MIE NJIT and Dr. Robert Haight from U.S. Forest Service)
PI, U.S. Forest Service Grant Contract, “Risk-Averse Surveillance and Intervention Planning for Emerald Ash Borer in Community Forests,” U.S. Forest Service Northern Research Station. St. Paul, MN, 07/01/2018–07/30/2019, $73,257 (co-PI–Dr. Robert Haight from U.S. Forest Service)
 PI, U.S. Forest Service Grant Contract, “Cost-effective Surveillance and Control Planning for Emerald Ash Borer in Community Forests,” U.S. Forest Service Northern Research Station. St. Paul, MN, 08/01/2016–08/31/2018, $129,775 (co-PI–Dr. Robert Haight from U.S. Forest Service)
PI, U.S. Forest Service Grant Contract, “A Principal-Agent Game Theoretical Model for Intervention Planning of Emerald Ash Borer in Public and Private Forests,” U.S. Forest Service Northern Research Station. St. Paul, MN, 05/10/2019–12/31/2021, $61,186 (co-PIs–Dr. Wenbo Cai from MIE NJIT and Dr. Robert Haight from U.S. Forest Service)
Congratulations to former doctoral student and SysOptiMaL member Xuecheng Yin who started to work as a tenure track Assistant Professor at Spears School of Business of Oklahoma State University! So PROUD of you, Xuecheng! (8/30/2023).
SysOptiMal member and former Ph.D. student Dogacan Yilmaz defended his dissertation with outstanding success and earned his doctoral degree on December 18, 2022. He will be joining CVS as a senior data scientist. Congratulations, Dr. Dogacan Yilmaz! (1/5/2023).
SysOptiMal group members received the INFORMS ENRE Best Publication Award in Natural Resources, 2022, Indianapolis, IN
SysOptiMal group members received the INFORMS Computing Society Harvey J. Greenberg Research Award, 2022, Indianapolis, IN 
SysOptiMal  advisor Dr. Esra Büyüktahtakιn Toy has moved to her new position as an Associate Professor with tenure at the Industrial & Systems Department of Virginia Tech, Blacksburg, VA, in August 2022 (8/1/2022).
Congratulations to former SODAL undergraduate research assistant Donald Andrews for earning a Reimagining Global Sustainability Postgraduate Scholarship at Trinity College to study international development in Dublin, Ireland! Here is his full story.
SODAL member and former Ph.D. student Chen Chen defended her dissertation successfully and earned her doctoral degree on July 27, 2022. Congratulations, Dr. Chen Chen! (7/27/2022).
Congratulations to former SODAL undergraduate research assistant Donald Andrews for earning a Reimagining Global Sustainability Postgraduate Scholarship at Trinity College to study international development in Dublin, Ireland! Here is his full story.
Journal article titled “A simulation-deep reinforcement learning (SiRL) approach for epidemic control optimization” co-authored by SODAL members Sabah Bushaj, Xuecheng Yin, Arjeta Beqiri, undergraduate student Donald Andrews and SODAL advisor Dr. Esra Büyüktahtakιn Toy, has been accepted for publication in Annals of Operations Research (7/28/2022).
Honored and thrilled that our IISE-T HSE article on “epidemic-vaccination-logistics” has been featured in the ISE magazine April issue. Here is the link for the featured article (4/15/2022).
Journal article by Dr. Esra Büyüktahtakιn Toy, “Stage-t Scenario Dominance for Risk-Averse Multi-Stage Stochastic Mixed-Integer Programs,” has been published online in Annals of Operations Research (12/1/2021).
Undergraduate research assistant and former SODAL member Bhumi Patel joined the University of Michigan Ann Arbor as a graduate student in January 2022. Congratulations Bhumi! (1/5/2022).
Journal article titled “Risk-Averse Multi-stage Stochastic Programming to Optimizing Vaccine Allocation and Treatment Logistics for Effective Epidemic Response” co-authored by SODAL members, Xuecheng Yin and Dr. Esra Büyüktahtakιn Toy, to appear in the upcoming issue of IISE Transactions on Healthcare Systems Engineering, has been selected as a featured article in the ISE magazine (2/11/2022).
SODAL member and Ph.D. student Dogacan Yilmaz defended his dissertation proposal titled "Integrated Machine Learning and Optimization Approaches" with great success on December 13, 2021. Congratulations Dogacan! (12/13/2021).
Journal article titled “COVID-19: Data-Driven optimal allocation of ventilator supply under uncertainty and risk” co-authored by SODAL members, Xuecheng Yin, Bhumi Patel, and Dr. Esra Büyüktahtakιn Toy has been accepted for publication in European Journal of Operational Research (11/26/2021).
SODAL member and former Ph.D. student Xuecheng Yin defended his dissertation with great accomplishments and earned his doctoral degree on July 28, 2021. Xuecheng joined Yale School of Public Health as a postdoctoral research associate on August 1, 2021. Congratulations Dr. Xuecheng Yin! (8/18/2021).
SODAL member and former Ph.D. student Sabah Bushaj confidently passed his dissertation defense with great success on July 27, 2021. Sabah is joining SUNY Plattsburgh as a tenure track Assistant Professor of Data Analytics starting August 25, 2021. Congratulations Dr. Sabah Bushaj! (8/18/2021).
Journal article titled “Risk-Averse Multi-Stage Stochastic Optimization for Surveillance and Operations Planning of a Forest Insect Infestation” co-authored by SODAL members, Sabah Bushaj and Dr. Esra Büyüktahtakιn Toy, and Dr. Robert Haight from the US Forest Service has been accepted for publication in European Journal of Operational Research (8/22/2021).
SODAL receives funding from USDA Forest Service. Dr. Büyüktahtakιn Toy serves as the lead PI of the team with CO-PI Dr. Selina Cai and collaborator Dr. Robert Haight from the US Forest Service, for a $25K grant to develop “Optimizing public-private partnership under a limited budget and heterogeneous participants: a game-theoretic optimization approach to EAB management ” (08/17/2021).
Journal article titled “Risk-Averse Multi-stage Stochastic Programming to Optimizing Vaccine Allocation and Treatment Logistics for Effective Epidemic Response” co-authored by SODAL members, Xuecheng Yin and Dr. Esra Büyüktahtakιn Toy has been accepted for publication in IISE Transactions on Healthcare Systems Engineering (5/29/2021).
SODAL member and undergraduate research assistant Bhumi Patel won the 2021 Provost Undergraduate Research and Innovation (URI) Award (4/27/2021).
SODAL receives funding from USDA Forest Service. Dr. Büyüktahtakιn Toy serves as the lead PI of the team with CO-PI Dr. Selina Cai and collaborator Dr. Robert Haight from the US Forest Service, for a $72.5K grant to develop “Optimizing public-private partnership under a limited budget and heterogeneous participants: a game-theoretic optimization approach to EAB management” (04/26/2021).
SODAL member and PhD candidate Xuecheng Yin won the first place at the 2021 Virtual Dana Knox Student Research Showcase by his presentation titled “A Data-Driven Stochastic Programming Epidemic Modeling Framework to Controlling the COVID-19” (4/23/2021).
Dr. Büyüktahtakιn Toy was invited to speak at the “CAREER Awardee Q&As - Reflections from Recent CAREER Awardees” panel in the 2021 NSF Engineering CAREER Proposal Writing Workshop virtually welcoming 800+ junior faculty from engineering schools nationwide (3/18/2021).
COVID-19 Publication: SODAL members PhD Candidate Xuecheng Yin, undergraduate student Bhumi Patel, and faculty advisor Dr. Esra Büyüktahtakın present the pre-print of their recent work on fighting against COVID-19  “COVID-19: Optimal Allocation of Ventilator Supply under Uncertainty and Risk,” which is under review for a journal (3/11/2021).
Journal article titled “A Multi-Stage Stochastic Programming Approach to Epidemic Resource Allocation with Equity Considerations” co-authored by SODAL members, Xuecheng Yin and Dr. Esra Büyüktahtakιn Toy has been accepted for publication in Health Care Management Science (2/19/2021).
Journal article titled “A New Multi-Stage Stochastic Programming Approach to the Optimal Surveillance and Control of Emerald Ash Borer in Cities” co-authored by former SODAL members, Dr. Eyyub Kibis, Najmaddin Akhundov, and Dr. Büyüktahtakιn Toy, and U.S. Forest Service researchers Drs. Robert Haight, Kathleen Knight, and Charlie Flower has been accepted for publication in INFORMS Journal on Computing (2/15/2020).
Congratulations to Xuecheng Yin, a doctoral student at SODAL, for successfully passing his doctoral proposal examination on April 30, 2020.
Congratulations to Sabah Bushaj, a doctoral student at SODAL, for successfully passing his doctoral proposal examination on April 23, 2020.
Journal article titled “Optimizing Surveillance and Management of Emerald Ash Borer in Urban Environments” co-authored by SODAL members Sabah Bushaj and Dr. Büyüktahtakιn Toy, and Canadian Forest Service Researcher Dr. Denys Yemshanov, and Dr. Robert Haight from the U.S. Forest Service has been accepted for publication by Natural Resources Modeling (4/10/2020).
Dr. Büyüktahtakιn Toy is serving as the “OR Track Chair” of the IISE Annual Conference, May 2020, Orlando, FL (8/12/2019)
Journal article titled “An integrated simulation-optimization framework to optimize search and treatment path for controlling a biological invader” co-authored by former SODAL members Dr. Sevilay Onal, Najmaddin Akhundov, and Dr. Esra Büyüktahtakın, and Jennifer Smith, Dr. Gregory R. Houseman from WSU Biology was published in the International Journal of Production Economics, 2020.
Congratulations to Dr. Sevilay Onal, a former postdoctoral research associate and SODAL member, who will be joining the University of Illinois Springfield as a tenure-track Assistant Professor of Management Information Systems (8/12/2019)
Dr. Büyüktahtakιn Toy was invited as a panel speaker for the “Best Practices in Teaching OR/MS” at the INFORMS Annual Meeting 2019, October 20-23, Seattle, WA
Dr. Büyüktahtakιn Toy was invited to give a talk at ICERM, Mathematical Optimization of Systems Impacted by Rare, High-Impact Random Events, June 24-28, 2019 Brown University, Providence, RI
Dr. Büyüktahtakιn Toy was invited to give a talk at the 2019 IISE Doctoral Colloquium at IISE Annual Conference, May 2019, Orlando, FL
SODAL receives funding from USDA Forest Service. Dr. Büyüktahtakιn Toy serves as the lead PI of the team with CO-PI Dr. Selina Cai and collaborator Dr. Robert Haight from the US Forest Service, for a $61K grant to develop
“A Principal-Agent Game Theoretical Model for Intervention Planning of Emerald Ash Borer in Public and Private Forests” (05/10/2019)
Journal article co-authored by former group member, Dr. Eyyub Kibis, and Dr. Büyüktahtakιn Toy has been accepted for publication by Mathematical Biosciences. The article titled  “Optimizing Multi-Modal Cancer Treatment under 3D Spatio-Temporal Tumor Growth” integrates the spread of cancer cells into a 3D spatio-temporal reaction-diffusion model of cancer growth while taking into account therapeutic (surgery, chemo-, and radio-therapy) effects to minimize the number of new cancer cells (10/25/2018).
SODAL receives funding from USDA Forest Service. Dr. Büyüktahtakιn Toy serves as the lead PI of the team with collaborator Dr. Robert Haight from the US Forest Service, for a $58K grant to address risk-averse resource allocation challenges to protect community forests from the threat of EAB. (07/01/2018)
Systems Optimization and Data Analytics Lab (SODAL) at NJIT seeks a highly qualified PhD student for a Graduate Research Assistant (GRA) position with a starting date of Fall 2020, for details, see GRA Position Announcement.
Journal article co-authored by Dr. Büyüktahtakιn Toy and former group members, Dr. Emmanuel des-Bordes and Dr. Eyyub Kibis, has been published by European Journal of Operational Research. The article titled  “A New Epidemics-Logistics Model: Insights into Controlling the Ebola Virus Disease in West Africa” addresses the resource allocation problem for epidemic control, which has been a core challenge in epidemiological modeling (3/16/2018).
Congratulations to Dr. Eyyub Kibis, a former PhD student and SODAL member, who has joined the Huether School of Business at the College of Saint Rose, Albany, New York, as a tenure-track Assistant Professor of Business Analytics (8/16/2017).