Browsing by Author "Tacoğlu, Melis Tan"

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Fuzzy Goal Programming Approach to Multi-objective Facility Location Problem for Emergency Goods and Services Distribution
(Springer Science and Business Media Deutschland GmbH, 2023) Mert Paldrak; Simge Güçlükol Ergin; Gamze Erdem; Melis Tan Tacoglu; Paldrak, Mert; Tacoğlu, Melis Tan; Ergin, Simge Güçlükol; Erdem, Gamze; C. Kahraman , I.U. Sari , B. Oztaysi , S. Cevik Onar , S. Cebi , A.C. Tolga
Ensuring the distribution of vital goods and services during emergency or post-disaster situations is crucial for meeting the needs of those affected as quickly as possible. The challenge lies in finding suitable and pertinent locations for facilities to efficiently distribute these goods and services. In such a situation location decisions for these facilities must be made considering multiple objectives. However in such a real-life problem the aspiration levels of each of the objectives are not certainly known due to unpredictable results of a disaster. Consequently the problem is formulated as fuzzy multi-objective facility location problem where two objectives are taken into consideration. We specifically consider minimization of total cost of facilities to be opened and minimization of total distance travelled by victims. Due to the conflicting nature of these objective functions we propose to employ two different fuzzy weighted goal programming techniques to find suitable compromise solutions for the problem. We present our developed models and provide results for three instances with different sizes. The proposed models are coded using IBM CPLEX Optimizer to obtain solutions in a reasonable amount of computational time. This paper contributes to the literature by providing two different fuzzy weighted goal programming techniques and comparing their efficiencies. © 2023 Elsevier B.V. All rights reserved.
Resolving Stakeholder Conflicts in Airport Gate Assignment: A Multi-objective Approach with Goal Programming and MIP Models
(Springer Science and Business Media Deutschland GmbH, 2025) Mert Paldrak; Gamze Erdem; Melis Tan Tacoglu; Mustafa Arslan Ornek; Paldrak, Mert; Örnek, Mustafa Arslan; Tacoğlu, Melis Tan; Erdem, Gamze; N.M. Durakbasa , K.G. Gülen
The Airport Gate Assignment Problem (AGAP) is a critical aspect of airport operations involving the assignment of gates to incoming and outgoing flights. In this study we model the AGAP as a multi-objective optimization problem addressing the conflicting preferences of key stakeholders: passengers airlines and airport management. Each stakeholder has distinct gate preferences creating challenges in balancing their competing objectives. To address these challenges we develop Mixed Integer Programming (MIP) models incorporating both assignment-based and time-tabling-based approaches. The solution process leverages Goal Programming techniques including Weighted Goal Programming Tchebychev Goal Programming and Lexicographic Goal Programming. The models are implemented and solved using IBM ILOG CPLEX Version 12.0 providing a robust framework for optimizing gate assignments while considering the complex trade-offs between stakeholder preferences. Our results offer insights into the effectiveness of these techniques in resolving conflicts and achieving an optimal balance in gate assignments. © 2025 Elsevier B.V. All rights reserved.