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Professor Kostas Nikolopoulos' Outputs (52)

Aggregate selection, individual selection, and cluster selection: an empirical evaluation and implications for systems research (2021)
Journal Article
Vangumalli, D., Nikolopoulos, K., & Litsiou, K. (2021). Aggregate selection, individual selection, and cluster selection: an empirical evaluation and implications for systems research. Cybernetics and Systems, 52(7), 553-578. https://doi.org/10.1080/01969722.2021.1902049

Data analysts when forecasting large number of time series, they regularly employ one of the following methodological approaches: either select a single forecasting method for the entire dataset (aggregate selection), or use the best forecasting meth... Read More about Aggregate selection, individual selection, and cluster selection: an empirical evaluation and implications for systems research.

Forecasting and planning during a pandemic: COVID-19 growth rates, supply chain disruptions, and governmental decisions (2020)
Journal Article
Nikolopoulos, K., Punia, S., Schäfers, A., Tsinopoulos, C., & Vasilakis, C. (2020). Forecasting and planning during a pandemic: COVID-19 growth rates, supply chain disruptions, and governmental decisions. European Journal of Operational Research, 290(1), 99-115. https://doi.org/10.1016/j.ejor.2020.08.001

Policymakers during 1COVID-19 operate in uncharted 2territory and must make tough decisions. Operational Research - the ubiquitous ‘science of better’ - plays a vital role in supporting this decision-making process. To that end, using data from the U... Read More about Forecasting and planning during a pandemic: COVID-19 growth rates, supply chain disruptions, and governmental decisions.

Non-Negativity of a Quadratic form with Applications to Panel Data Estimation, Forecasting and Optimization (2020)
Journal Article
Pochiraju, B., Seshadri, S., Thomakos, D. D., & Nikolopoulos, K. (2020). Non-Negativity of a Quadratic form with Applications to Panel Data Estimation, Forecasting and Optimization. Stats, 3(3), 185-202. https://doi.org/10.3390/stats3030015

For a symmetric matrix B, we determine the class of Q such that QtBQ is non-negative definite and apply it to panel data estimation and forecasting: the Hausman test for testing the endogeneity of the random effects in panel data models. We show that... Read More about Non-Negativity of a Quadratic form with Applications to Panel Data Estimation, Forecasting and Optimization.

Superforecasting reality check: Evidence from a small pool of experts and expedited identification (2020)
Journal Article
Katsagounos, I., Thomakos, D. D., Litsiou, K., & Nikolopoulos, K. (2021). Superforecasting reality check: Evidence from a small pool of experts and expedited identification. European Journal of Operational Research, 289(1), 107-117. https://doi.org/10.1016/j.ejor.2020.06.042

Superforecasting has drawn the attention of academics - despite earlier contradictory findings in the literature, arguing that humans can consistently and successfully forecast over long periods. It has also enthused practitioners, due to the major i... Read More about Superforecasting reality check: Evidence from a small pool of experts and expedited identification.

We need to talk about intermittent demand forecasting (2020)
Journal Article
Nikolopoulos, K. (2021). We need to talk about intermittent demand forecasting. European Journal of Operational Research, 291(2), 549-559. https://doi.org/10.1016/j.ejor.2019.12.046

Operational Research (OR) is the ‘science of better’. People constantly try to get better, in practically all aspects of their personal and professional life, and thus OR is de facto a ubiquitous science. What might however not be that clear, is that... Read More about We need to talk about intermittent demand forecasting.