Endüstri Mühendisliği Bölümü yayınlarını içerir. http://hdl.handle.net/20.500.12416/279 2026-10-28T17:59:49Z 2026-10-28T17:59:49Z Arslan, Caner Karasakal, Orhan Kırca, Ömer http://hdl.handle.net/20.500.12416/8488 2024-06-12T12:04:17Z 2024-01-01T00:00:00Z

Naval Air Defense Planning problem: A novel formulation and heuristics Arslan, Caner; Karasakal, Orhan; Kırca, Ömer This article focuses on air defense in maritime environment, which involves protecting friendly naval assets from aerial threats. Specifically, we define and address the Naval Air Defense Planning (NADP) problem, which consists of maneuvering decisions of the ships and scheduling weapons and sensors to the threats in order to maximize the total expected survival probability of friendly units. The NADP problem is more realistic and applicable than previous studies, as it considers features such as sensor assignment requirements, weapon and sensor blind sectors, sequence-dependent setup times, and ship's infrared/radar signature. In this study, a mixed-integer nonlinear programming model of the NADP problem is presented and heuristic solution approaches are developed. Computational results demonstrate that these heuristic approaches are both fast and efficient in solving the NADP problem.

2024-01-01T00:00:00Z Karadağ, Ayyüce Aydemir Akdere, Erol http://hdl.handle.net/20.500.12416/8445 2024-05-30T08:10:44Z 2023-06-01T00:00:00Z

Design of a distribution network for the school lunch program Karadağ, Ayyüce Aydemir; Akdere, Erol The national school lunch program (NSLP) is crucial for providing healthy, inexpensive, or free lunches to children, thus benefiting society. Designing a distribution network for the program requires solving a location and routing problem. In this paper, first, we formulate a multi-objective non-linear integer programming formulation of the problem. Next, we develop a two-step approach since the problem is Np-hard. The first stage presents a K-mean clustering method that deals with routing decisions by determining the locations of food processing centers and allocating schools to these centers. The second stage offers a multi-objective mixed-integer linear mathematical model for finding the locations of distribution centers. Besides economic and environmental factors, we optimize travel time in the network as perishable items are involved. A weighted sum approach is presented for different weights of objectives. We provide a real case study in Turkey to demonstrate the applicability of the two-stage approach proposed in this study. The numerical results provide valuable information for decision-makers and authorities to prioritize and prepare action plans.

2023-06-01T00:00:00Z Ertem, Mustafa Alp http://hdl.handle.net/20.500.12416/8349 2024-05-14T11:11:32Z 2016-07-19T00:00:00Z

Türkiye’de Lojistik Sektörü ve Devlet Malzeme Ofisi’nin Durumu Ertem, Mustafa Alp Devlet Malzeme Ofisi (DMO), kamu kurumlarının belirli ihtiyaçlarını satınalma görevini üstlenmiş bir Kamu İktisadi Teşebbüsü (KİT)’dür. Bu çalışmanın amacı DMO’nun lojistik açıdan mevzuattaki yükümlülükleri ile lojistik faaliyetlerini incelemek ve DMO’ya alternatif seçenekler sunmaktır. Bu çalışmanın özgün yönü Türkiye’de 60 yıldır merkezi satınalma kuruluşu olarak görev yapan DMO’nun lojistik yükümlülüklerinin, hâlihazırdaki lojistik faaliyetlerinin durumunun ve geliştirme önerilerinin ilk defa sunulmuş olmasıdır. Öneriler depolama, taşımacılık ve tesis yeri seçimi alt konularında sunulmuştur. DMO için en olası senaryolar (1) Mevcut depolardan maliyet etkin olmayanların kapatılarak sezonluk depoların kiralanması, (2) DMO araçlarıyla yapılan nakliyenin azaltılması ve (3) Kapatılacak/kiralanacak depolar için yer tespiti olarak sıralanabilir.

2016-07-19T00:00:00Z Çetinkaya, Ferda Can Duman, Mehmet http://hdl.handle.net/20.500.12416/8225 2024-05-09T11:19:35Z 2021-01-01T00:00:00Z

Scheduling With Lot Streaming In A Two-Machine Re-Entrant Flow Shop Çetinkaya, Ferda Can; Duman, Mehmet Lot streaming is splitting a job-lot of identical items into several sublots (portions of a lot) that can be moved to the next machines upon completion so that operations on successive machines can be overlapped; hence, the overall performance of a multi-stage manufacturing environment can be improved. In this study, we consider a scheduling problem with lot streaming in a two-machine re-entrant flow shop in which each job-lot is processed first on Machine 1, then goes to Machine 2 for its second operation before it returns to the primary machine (either Machine 1 or Machine 2) for the third operation. For the two cases of the primary machine, both single-job and multi-job cases are studied independently. Optimal and near-optimal solution procedures are developed. Our objective is to minimize the makespan, which is the maximum completion time of the sublots and job lots in the single-job and multi-job cases, respectively. We prove that the single-job problem is optimally solved in polynomial-time regardless of whether the third operation is performed on Machine 1 or Machine 2. The multi-job problem is also optimally solvable in polynomial time when the third operation is performed on Machine 2. However, we prove that the multi-job problem is NP-hard when the third operation is performed on Machine 1. A global lower bound on the makespan and a simple heuristic algorithm are developed. Our computational experiment results reveal that our proposed heuristic algorithm provides optimal or near-optimal solutions in a very short time.

2021-01-01T00:00:00Z