Akademik Veri Yönetim Sistemi
Creating A Human-Focused Future, Serra Çelik,Sevinç Gülseçen,Meltem Eryılmaz, Editör, Istanbul University Press, İstanbul, ss.20-30, 2025
The Turkish Post and Telegraph Organization, commonly known as PTT is Türkiye's national postal service. In an optimization-related context, a postal and logistics provider can concentrate on reducing transportation costs through strategic optimization of its distribution network. Currently, the PTT network comprises 479 branches and 134 distribution centers. Our analysis investigates the alternative locations for the 134 centers using various optimization techniques. Heuristics and Mixed Integer Programming (MIP) are among the common approaches for binary variable p-median model commonly used in facility location optimization. Given the NP-hard nature of the p-median problem, researchers often advocate for the use of heuristics, particularly when addressing larger-scale instances.
Currently, there is no universal cutoff model size for choosing between heuristics (approximate methods) and exact solvers. In order to address this uncapacitated p-median model with 134 binary variables; we assess the feasibility and usability of the two approaches to the current size by implementing various Genetic Algorithm (GA) models, testing different GA parameters to evaluate their impact on model efficiency and we applied Mixed-Integer Programming (MIP) optimization using the GLPK solver.
The complexity of NP-hard problems grows exponentially but the study demonstrates that MIP methods remain effective for the current variable size and model structure. They provided the best solution with a fitness score of 90411.59 versus 154218.99 for the current network. The results underscore the significant impact of generation size on both runtime and solution quality in GA approaches, which provided also practical, near-optimal solutions within longer but still acceptable timeframes (fitness score: 95,349.7 in approximately 45 minutes). In conclusion, both strategies could aid PTT size postal and logistics provider in reducing expenses while enhancing service quality.