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3. Integer programming models for the semi-obnoxious p-median problem

Author

Ploskas, Nikolaos and Stergiou, Kostas

Subjects
Mathematics - Optimization and Control, 90-10, 90C10, 65K05
Abstract

The p-median problem concerns the location of facilities so that the sum of distances between the demand points and their nearest facility is minimized. We study a variant of this classic location problem where minimum distance constraints exist both between the facilities and between the facilities and the demand points. This specific type of problem can be used to model situations where the facilities to be located are semi-obnoxious. But despite its relevance to real life scenarios, it has received little attention within the vast literature on location problems. We present twelve ILP models for this problem, coupling three formulations of the p-median problem with four formulations of the distance constraints. We utilize Gurobi Optimizer v9.0.3 in order to compare these ILP models on a large dataset of problems. Experimental results demonstrate that the classic p-median model proposed by ReVelle \& Swain and the model proposed by Rosing et al. are the best performers.

Published
2022

7. Optimization of circuitry arrangements for heat exchangers using derivative-free optimization

Author

Ploskas, Nikolaos, Laughman, Christopher, Raghunathan, Arvind U., and Sahinidis, Nikolaos V.

Subjects
Computer Science - Computational Engineering, Finance, and Science
Abstract

Optimization of the refrigerant circuitry can improve a heat exchanger's performance. Design engineers currently choose the refrigerant circuitry according to their experience and heat exchanger simulations. However, the design of an optimized refrigerant circuitry is difficult. The number of refrigerant circuitry candidates is enormous. Therefore, exhaustive search algorithms cannot be used and intelligent techniques must be developed to explore the solution space efficiently. In this paper, we formulate refrigerant circuitry design as a binary constrained optimization problem. We use CoilDesigner, a simulation and design tool of air to refrigerant heat exchangers, in order to simulate the performance of different refrigerant circuitry designs. We treat CoilDesigner as a black-box system since the exact relationship of the objective function with the decision variables is not explicit. Derivative-free optimization (DFO) algorithms are suitable for solving this black-box model since they do not require explicit functional representations of the objective function and the constraints. The aim of this paper is twofold. First, we compare four mixed-integer constrained DFO solvers and one box-bounded DFO solver and evaluate their ability to solve a difficult industrially relevant problem. Second, we demonstrate that the proposed formulation is suitable for optimizing the circuitry configuration of heat exchangers. We apply the DFO solvers to 17 heat exchanger design problems. Results show that TOMLAB/glcDirect and TOMLAB/glcSolve can find optimal or near-optimal refrigerant circuitry designs after a relatively small number of circuit simulations.

Published
2017
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8. Power Consumption Estimation in Data Centers Using Machine Learning Techniques

Author

Karantoumanis, Emmanouil, Ploskas, Nikolaos, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Kotsireas, Ilias S., editor, and Pardalos, Panos M., editor

Published
2020
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9. Predicting the Execution Time of the Interior Point Method for Solving Linear Programming Problems Using Artificial Neural Networks

Author

Voulgaropoulou, Sophia, Samaras, Nikolaos, Ploskas, Nikolaos, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Matsatsinis, Nikolaos F., editor, Marinakis, Yannis, editor, and Pardalos, Panos, editor

Published
2020
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11. AHP

Author

Papathanasiou, Jason, Ploskas, Nikolaos, Pardalos, Panos M., Managing Editor, Du, Ding-Zhu, Editor-in-Chief, Papathanasiou, Jason, and Ploskas, Nikolaos

Published
2018
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12. Goal Programming

Author

Papathanasiou, Jason, Ploskas, Nikolaos, Pardalos, Panos M., Managing Editor, Du, Ding-Zhu, Editor-in-Chief, Papathanasiou, Jason, and Ploskas, Nikolaos

Published
2018
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13. SIR

Author

Papathanasiou, Jason, Ploskas, Nikolaos, Pardalos, Panos M., Managing Editor, Du, Ding-Zhu, Editor-in-Chief, Papathanasiou, Jason, and Ploskas, Nikolaos

Published
2018
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14. VIKOR

Author

Papathanasiou, Jason, Ploskas, Nikolaos, Pardalos, Panos M., Managing Editor, Du, Ding-Zhu, Editor-in-Chief, Papathanasiou, Jason, and Ploskas, Nikolaos

Published
2018
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15. PROMETHEE

Author

Papathanasiou, Jason, Ploskas, Nikolaos, Pardalos, Panos M., Managing Editor, Du, Ding-Zhu, Editor-in-Chief, Papathanasiou, Jason, and Ploskas, Nikolaos

Published
2018
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16. TOPSIS

Author

Papathanasiou, Jason, Ploskas, Nikolaos, Pardalos, Panos M., Managing Editor, Du, Ding-Zhu, Editor-in-Chief, Papathanasiou, Jason, and Ploskas, Nikolaos

Published
2018
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17. Heat Exchanger Circuitry Design by Decision Diagrams

Author

Ploskas, Nikolaos, Laughman, Christopher, Raghunathan, Arvind U., Sahinidis, Nikolaos V., Hutchison, David, Editorial Board Member, Kanade, Takeo, Editorial Board Member, Kittler, Josef, Editorial Board Member, Kleinberg, Jon M., Editorial Board Member, Mattern, Friedemann, Editorial Board Member, Mitchell, John C., Editorial Board Member, Naor, Moni, Editorial Board Member, Pandu Rangan, C., Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Terzopoulos, Demetri, Editorial Board Member, Tygar, Doug, Editorial Board Member, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Rousseau, Louis-Martin, editor, and Stergiou, Kostas, editor

Published
2019
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18. Energy Hub Optimization on Residential Building Case

Author

Kilis Vasileios, Paschalidis Nikolaos, Ploskas Nikolaos, and Panaras Giorgos

Subjects
Environmental sciences, GE1-350
Abstract

The growth of the energy consumed, have led to the need of upgrading and restructuring the operation of existing energy systems in the building sector. In context, goals of reducing the primary energy consumption based on fossil fuels and the limitation of carbon dioxide (CO2) emissions to the atmosphere, were set, in order to enhance the provision of affordable and generally clean energy for the citizens. In addition, the European Union (EU) promotes the utilization of energy systems based on Renewable Energy Sources (RES). Αll above highlight the importance of the decision-making process during the design phase of a building. For these reasons, this paper deals with the optimization of multi energy systems, introducing the concept of the Energy Hub, in order to cover the thermal demands of a residential building located in Thessaloniki (Greece). The proposed methodology includes the calculation of the building energy demands on a monthly basis via the simulation program FineGREEN19. Afterwards, a Mathematical Programming model was constructed, in order to provide the optimization scheme of multi energy systems, considering different criteria. The criteria include the minimization of economic, energy and environmental aspects, considering the concept of Life Cycle Assessment (LCA). The General Algebraic Modeling System (GAMS) was used to model the optimization problem. The results of Single Criteria Optimization problem figure out the contradictory between the criteria, showing that the use of the optimization models can improve and facilitate the building design.

Published
2023
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23. Pivoting Rules

Author

Ploskas, Nikolaos, Samaras, Nikolaos, Pardalos, Panos M., Managing Editor, Du, Ding-Zhu, Editor-in-Chief, Ploskas, Nikolaos, and Samaras, Nikolaos

Published
2017
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25. Scaling Techniques

Author

Ploskas, Nikolaos, Samaras, Nikolaos, Pardalos, Panos M., Managing Editor, Du, Ding-Zhu, Editor-in-Chief, Ploskas, Nikolaos, and Samaras, Nikolaos

Published
2017
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26. Presolve Methods

Author

Ploskas, Nikolaos, Samaras, Nikolaos, Pardalos, Panos M., Managing Editor, Du, Ding-Zhu, Editor-in-Chief, Ploskas, Nikolaos, and Samaras, Nikolaos

Published
2017
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27. Linear Programming Algorithms

Author

Ploskas, Nikolaos, Samaras, Nikolaos, Pardalos, Panos M., Managing Editor, Du, Ding-Zhu, Editor-in-Chief, Ploskas, Nikolaos, and Samaras, Nikolaos

Published
2017
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28. Interior Point Methods

Author

Ploskas, Nikolaos, Samaras, Nikolaos, Pardalos, Panos M., Managing Editor, Du, Ding-Zhu, Editor-in-Chief, Ploskas, Nikolaos, and Samaras, Nikolaos

Published
2017
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29. Introduction

Author

Ploskas, Nikolaos, Samaras, Nikolaos, Pardalos, Panos M., Managing Editor, Du, Ding-Zhu, Editor-in-Chief, Ploskas, Nikolaos, and Samaras, Nikolaos

Published
2017
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31. Sensitivity Analysis

Author

Ploskas, Nikolaos, Samaras, Nikolaos, Pardalos, Panos M., Managing Editor, Du, Ding-Zhu, Editor-in-Chief, Ploskas, Nikolaos, and Samaras, Nikolaos

Published
2017
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35. Implementation of an Extended Fuzzy VIKOR Method Based on Triangular and Trapezoidal Fuzzy Linguistic Variables and Alternative Deffuzification Techniques

Author

Ploskas, Nikolaos, Papathanasiou, Jason, Tsaples, Georgios, van der Aalst, Wil M.P., Series editor, Mylopoulos, John, Series editor, Rosemann, Michael, Series editor, Shaw, Michael J., Series editor, Szyperski, Clemens, Series editor, Linden, Isabelle, editor, Liu, Shaofeng, editor, and Colot, Christian, editor

Published
2017
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37. A Decision Support System for Multiple Criteria Alternative Ranking Using TOPSIS and VIKOR: A Case Study on Social Sustainability in Agriculture

Author

Papathanasiou, Jason, Ploskas, Nikolaos, Bournaris, Thomas, Manos, Basil, van der Aalst, Wil, Series editor, Mylopoulos, John, Series editor, Rosemann, Michael, Series editor, Shaw, Michael J., Series editor, Szyperski, Clemens, Series editor, Liu, Shaofeng, editor, Delibašić, Boris, editor, and Oderanti, Festus, editor

Published
2016
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39. A Collaborative Spatial Decision Support System for the Capacitated Vehicle Routing Problem on a Tabletop Display

Author

Ploskas, Nikolaos, Athanasiadis, Ioannis, Papathanasiou, Jason, Samaras, Nikolaos, van der Aalst, Wil, Series editor, Mylopoulos, John, Series editor, Rosemann, Michael, Series editor, Shaw, Michael J., Series editor, Szyperski, Clemens, Series editor, Linden, Isabelle, editor, Liu, Shaofeng, editor, Dargam, Fátima, editor, and E. Hernández, Jorge, editor

Published
2015
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40. A Tangible Collaborative Decision Support System for Various Variants of the Vehicle Routing Problem

Author

Ploskas, Nikolaos, Athanasiadis, Ioannis, Papathanasiou, Jason, Samaras, Nikolaos, van der Aalst, Wil, Series editor, Mylopoulos, John, Series editor, Rosemann, Michael, Series editor, Shaw, Michael J., Series editor, Szyperski, Clemens, Series editor, Delibašić, Boris, editor, Hernández, Jorge E., editor, Papathanasiou, Jason, editor, Dargam, Fátima, editor, Zaraté, Pascale, editor, Ribeiro, Rita, editor, Liu, Shaofeng, editor, and Linden, Isabelle, editor

Published
2015
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41. The p-Dispersion Problem with Distance Constraints

Author

Nikolaos Ploskas and Kostas Stergiou and Dimosthenis C. Tsouros, Ploskas, Nikolaos, Stergiou, Kostas, Tsouros, Dimosthenis C., Nikolaos Ploskas and Kostas Stergiou and Dimosthenis C. Tsouros, Ploskas, Nikolaos, Stergiou, Kostas, and Tsouros, Dimosthenis C.

Abstract

In the (maxmin) p-dispersion problem we seek to locate a set of facilities in an area so that the minimum distance between any pair of facilities is maximized. We study a variant of this problem where there exist constraints specifying the minimum allowed distances between the facilities. This type of problem, which we call PDDP, has not received much attention within the literature on location and dispersion problems, despite its relevance to real scenarios. We propose both ILP and CP methods to solve the PDDP. Regarding ILP, we give two formulations derived from a classic and a state-of-the-art model for p-dispersion, respectively. Regarding CP, we first give a generic model that can be implemented within any standard CP solver, and we then propose a specialized heuristic Branch&Bound method. Experiments demonstrate that the ILP formulations are more efficient than the CP model, as the latter is unable to prove optimality in reasonable time, except for small problems, and is usually slower in finding solutions of the same quality than the ILP models. However, although the ILP approach displays good performance on small to medium size problems, it cannot efficiently handle larger ones. The heuristic CP-based method can be very efficient on larger problems and is able to quickly discover solutions to problems that are very hard for an ILP solver.

Published
2023
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42. A Web-Based Decision Support System for the Multiple Capacitated Facility Location Problem

Author

Papathanasiou, Jason, Ploskas, Nikolaos, Samaras, Nikolaos, van der Aalst, Wil, Series editor, Mylopoulos, John, Series editor, Rosemann, Michael, Series editor, Shaw, Michael J., Series editor, Szyperski, Clemens, Series editor, Dargam, Fátima, editor, Hernández, Jorge E., editor, Zaraté, Pascale, editor, Liu, Shaofeng, editor, Ribeiro, Rita, editor, Delibašić, Boris, editor, and Papathanasiou, Jason, editor

Published
2014
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45. VIKOR

Author

Papathanasiou, Jason, primary and Ploskas, Nikolaos, additional

Published
2018
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46. SIR

Author

Papathanasiou, Jason, primary and Ploskas, Nikolaos, additional

Published
2018
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47. TOPSIS

Author

Papathanasiou, Jason, primary and Ploskas, Nikolaos, additional

Published
2018
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48. AHP

Author

Papathanasiou, Jason, primary and Ploskas, Nikolaos, additional

Published
2018
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