Research

My research interests: Statistical distributions and modeling; Statistical machine learning; Data visualization; Mathematics education

My work focuses on developing flexible statistical distributions and modern regression methodologies for modeling complex and heterogeneous data. I construct and extend probability distributions with enhanced tail behavior, skewness, and shape flexibility to improve modeling of extremes, financial risk, and heterogeneous data structures.

A central theme of my research is integrating rigorous theoretical development with practical applications. I design new families of distributions using generator-based frameworks and study their properties, inferential procedures, and performance through real data applications. I also extend these ideas to modern regression settings, particularly generalized LASSO-type models for robust variable selection.

I actively involve undergraduate and graduate students in research projects to promote experiential learning and foster the development of future data scientists. My collaborators include Prof. Felix Famoye, Prof. Carl Lee, Prof. Broderick Oluyede, Prof. Mavis Pararai, and other national and international colleagues. 

• Warahena-Liyanage, G., Oluyede, B. & Moakofi, T. The New Ristić-Balakrishnan-Heavy-Tailed-Type II Topp-Leone-G Family of Distributions with Applications. (2025). Journal of Statistical Theory and Applications, Springer Nature. DOI

•  Moakofi, T., Puoetsile, A., Oluyede, B., & Warahena-Liyanage, G. (2024). A New Generalized Family of Weibull-Exponentiated Half Logistic-G Distribution with Applications, Central European Journal of Economic Modelling and Econometrics,16(2), 125-189. DOI

• Oluyede, B., Gabanakgosi, M., & Warahena-Liyanage, G. (2024). The Marshall-Olkin-Topp-Leone-Gompertz-G Family of Distributions with Applications. Statistics, Optimization & Information Computing, 12(4), 882-906. DOI

• Warahena Liyanage, G., Gabanakgosi, M., & Oluyede, B. (2023). Generalized Topp-Leone-G power series class of distributions: properties and applications. Electronic Journal of Applied Statistical Analysis, 16(3), 564-583. DOI 

• Warahena-Liyanage, G.; Oluyede, B.; Moakofi, T.; Sengweni, W. (2023). The New Exponentiated Half Logistic-Harris-G Family of Distributions with Actuarial Measures and Applications. Stats, 6, 773–801. DOI

• Warahena-Liyanage, G., Famoye, F., & Lee, C. (2023). A Generalization of LASSO Modeling via Bayesian Interpretation. Austrian Journal of Statistics, 52(4), 15–45. DOI 

• Oluyede, B., & Warahena-Liyanage, G. (2023). The Gamma Odd Weibull Generalized-G Family of Distributions: Properties and Applications. Revista Colombiana de Estadística (Colombian Journal of Statistics), 46(1), 1-44. DOI 

• Wijetunge, T. M. K., Premadasa, K., Warahena-Liyanage, G., Collins, B., Appuhamy, A., & Ratnayake, J. K. (2022). A Tale of Two Continents: Factors Influencing Students to Major in Mathematics. Journal of Higher Education Theory and Practice, 22(14). DOI 

• Wijetunge, T. M., Spann, A. G., Warahena-Liyanage, G., & St John, D. (2020). Significance of the Length of Instructions with Technology: What Pre-Service Teachers Say?. Journal of Educational Technology, 17(1), 22-34. DOI 

• Pararai, M., Warahena-Liyanage, G., & Oluyede, B. O. (2017). Exponentiated power Lindley–Poisson distribution: Properties and applications. Communications in Statistics-Theory and Methods, 46(10), 4726-4755. DOI 

• Oluyede, B., Foya, S., Warahena-Liyanage, G., & Huang, S. (2016). The Log-Logistic Weibull Distribution with Applications to Lifetime Data. Austrian Journal of Statistics, 45(3), 43-69. DOI 

• Oluyede, B. O., Warahena-Liyanage, G., & Pararai, M. (2016). The Beta Lindley-Poisson Distribution with Applications. Journal of Statistical and Econometric Methods, 5(4), 1. Link 

• Oluyede, B. O., Motsewabagale, G., Huang, S., Warahena-Liyanage, G., & Pararai, M. (2016). Dagum-Poisson distribution: model, properties, and application. Electronic Journal of Applied Statistical Sciences, 9(1), 169. DOI 

• Oluyede, B. O., Warahena-Liyanage, G., & Pararai, M. (2016). A new compound class of log-logistic Weibull–Poisson distribution: model, properties, and applications. Journal of Statistical Computation and Simulation, 86(7), 1363-1391. DOI 

• Pararai, M., Warahena-Liyanage, G., & Oluyede, B. O. (2015). Extended Lindley Poisson Distribution. Journal of Mathematics and Statistical Science, 1(5), 167. Link

• Pararai, M., Warahena-Liyanage, G., & Oluyede, B. O. (2015). A new class of generalized power Lindley distribution with applications to lifetime data. Theoretical mathematics and applications, 5(1), 53. Link 

• Warahena-Liyanage, G., & Pararai, M. (2015). The Lindley power series class of distributions: model, properties, and applications. Journal of Computations & Modelling 5, 35-80. Link

• Pararai, M., Oluyede, B. O., & Warahena-Liyanage, G.  (2015). Kumaraswamy Lindley-Poisson distribution: theory and applications. Asian Journal of Mathematics and Applications, 2015. Link

• Warahena-Liyanage, G., & Pararai, M. (2014). A generalized power Lindley distribution with applications. Asian Journal of Mathematics and Applications, 2014. Link

• Pararai, M., Warahena-Liyanage, G., & Oluyede, B. O. (2014). A New Class of Generalized Inverse Weibull Distribution with Applications. Journal of Applied Mathematics and Bioinformatics, 4(2), 17. Link

• 2023 Dr. Kenneth C. Schraut Faculty Research Award in Mathematics, $1200.

• Experiential Learning Innovation Fund for Faculty (ELIFF), Ying-Ju Chen, Gayan Warahena-Liyanage & Matthew Wascher, $750 (December 2022).

• Travel Grant Award for Junior Researcher Speakers at International Conference on Statistical Distributions and Applications (ICOSDA), $800 (October 2022).

Professional Meetings 

• Colloquium, Department of Mathematics, University of Dayton, “A New Flexible Family of Distributions Based on the Generalized Topp-Leone-G Power Series Framework”. Oct 16, 2025.

• 2025 Joint Statistical Meetings (JSM 2025), “Modification to the LASSO Regression Model via its Bayesian Interpretation”, Nashville, TN. Contributed Presentation. Aug 2-7, 2025.

• Tenth International Conference on Statistics for Twenty-first Century (ICSTC), “Generalized Topp-Leone-G Power Series Distributions: properties and applications”, University of Kerala, India. Invited Virtual Presentation. Dec 15, 2024.

• 2024 Symposium on Data Science & Statistics (SDSS), “A Generalized LASSO Model via Bayesian Interpretation”, Richmond, VA. Contributed Presentation. June 4-7, 2024.

• 8th Costal Bend Mathematics & Statistics Conference (8CBMSC), “Modify the LASSO Regression Model via its Bayesian Interpretation”, Texas A&M University Kingsville. Contributed Virtual Presentation. Apr 6, 2024.

• Third Central Botswana Mathematics and Statistical Sciences (CBMSS) Conference, “The well-known LASSO regression model modified with generalized distributions”, Department of Mathematics and Statistical Sciences, Botswana International University of Science and Technology, Palapye, Botswana. Invited Virtual Presentation. Mar 14-15, 2024.

• International Conference on Statistics and Data Science (ICSDS) in conjunction with 45th Annual Conference of Kerala Statistical Association, “A Generalization of the Laplace Distribution and its Application to the LASSO Regression Model”, Sree Sankara College, Kalady, India. Contributed Virtual Presentation. Jan 22-24, 2024.

• Ninth International Conference on Statistics for Twenty-first Century (ICSTC), “A Generalization of the Laplace Distribution and its Application to the LASSO Regression Model”, University of Kerala, India. Invited Virtual Presentation. Dec 15-16, 2023.

• International Conference on Statistical Distributions and Applications (ICOSDA), “A Generalization LASSO Modeling via Bayesian Interpretation”, Marshall University, Huntington, WV. Invited Presentation. Oct 13 -15, 2022.

• Allegheny Mountain Section Meeting of the Mathematical Association of America (MAA), “Mars Rover Optimal Path Determination”, Westminster College, New Wilmington, PA. Contributed Presentation. 2014. 

Other Talks

• UD Math Club Talk, “LASSO”, University of Dayton, Dayton, OH. Invited Presentation. Nov 14, 2022.

• CMU’s Annual Student Research and Creative Endeavors Exhibition, “Prevalence of Coronary Heart Disease in Rural and Urban areas in the United States in 2016”, Central Michigan University, Mount Pleasant, MI. Contributed Presentation. 2018.

• Second Mathematics Department Student Presentation Day, “Matching Algorithms with Utility Theory”, Department of Mathematics, Indiana University of Pennsylvania, Indiana, PA. Contributed Presentation. 2014. 

• Second Mathematics Department Student Presentation Day, “Elimination and Clinching Optimization in Baseball”, Department of Mathematics, Indiana University of Pennsylvania, Indiana, PA. Contributed Presentation. 2014. 

• Second Mathematics Department Student Presentation Day, “Mars Rover Optimal Path Determination”, Department of Mathematics, Indiana University of Pennsylvania, Indiana, PA. Contributed Presentation. 2014. 

• Internship Presentation Series 2010, “Software Tools: A Factory Status Visualization System, A Planning Tool and A Defects Analyzing Tool”, Department of Mathematics, University of Peradeniya, Sri Lanka. Contributed Presentation. 2010. 

• Internship Presentation Series 2010, “Quality Improvement Using Techniques in Statistical Quality Control”, Department of Mathematics, University of Peradeniya, Sri Lanka. Contributed Presentation. 2010. 

• Seminar Presentation Series 2009, “Determination of An Optimal Route to Minimize the Fuel Cost Using the Concepts in Travelling Salesman Problem (TSP)”, Department of Mathematics, University of Peradeniya, Sri Lanka. Contributed Presentation. 2009.