Endüstri Mühendisliği Bölümü Yayın Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/279

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Citation Count: Aydemir-Karadag, Ayyuce, "A profit-oriented mathematical model for hazardous waste locating-routing problem", Journal of Cleaner Production, Vol. 202, pp. 213-225, (2018).
A profit-oriented mathematical model for hazardous waste locating-routing problem
(Elsevier SCI LTD, 2018) Aydemir-Karadağ, Ayyüce; 116059
Hazardous waste management (HWM) deals with the safe, efficient and cost effective collection, transportation, treatment and disposal of wastes. This paper presents a profit-oriented mixed integer mathematical model for the hazardous waste location-routing problem, which incorporates the energy recovery from waste and the application of the polluter pays principle. The suggested model decides on the locations and numbers of recycling, incineration, sterilization, interim storage and disposal centers and on how to transfer various types of hazardous waste and waste residues among these centers from the perspective of environmental protection. The proposed model was implemented in a real life case study and tested on various hypothetical problem instances. In addition, an extended formulation was developed on a rolling horizon basis through the objective function of Net Present Value (NPV) to analyze the overall profitability of the entire HWM system for long-term planning and a sensitivity study was conducted on different interest rates. The results show that the model is applicable to real-life waste management systems and it can provide effective solutions for large-scale HWM problems. (C) 2018 Elsevier Ltd. All rights reserved.
Citation Count: Aydemir Karadağ, Ayyüce (2021). "Bi-Objective Adaptive Large Neighborhood Search Algorithm for the Healthcare Waste Periodic Location Inventory Routing Problem", Arabian Journal for Science and Engineering.
Bi-Objective Adaptive Large Neighborhood Search Algorithm for the Healthcare Waste Periodic Location Inventory Routing Problem
(2021) Aydemir Karadağ, Ayyüce; 116059
There has been an unexpected increase in the amount of healthcare waste during the COVID-19 pandemic. Managing healthcare waste is vital, as improper practices in the waste system can lead to the further spread of the virus. To develop effective and sustainable waste management systems, decisions in all processes from the source of the waste to its disposal should be evaluated together. Strategic decisions involve locating waste processing centers, while operational decisions deal with waste collection. Although the periodic collection of waste is used in practice, it has not been studied in the relevant literature. This paper integrates the periodic inventory routing problem with location decisions for designing healthcare waste management systems and presents a bi-objective mixed-integer nonlinear programming model that minimizes operating costs and risk simultaneously. Due to the complexity of the problem, a two-step approach is proposed. The first stage provides a mixed-integer linear model that generates visiting schedules to source nodes. The second stage offers a Bi-Objective Adaptive Large Neighborhood Search Algorithm (BOALNS) that processes the remaining decisions considered in the problem. The performance of the algorithm is tested on several hypothetical problem instances. Computational analyses are conducted by comparing BOALNS with its other two versions, Adaptive Large Neighborhood Search Algorithm and Bi-Objective Large Neighborhood Search Algorithm (BOLNS). The computational experiments demonstrate that our proposed algorithm is superior to these algorithms in several performance evaluation metrics. Also, it is observed that the adaptive search engine increases the capability of BOALNS to achieve high-quality Pareto-optimal solutions.
Citation Count: Karadağ, Ayyüce Aydemir; Akdere, Erol (2023). "Design of a distribution network for the school lunch program", Journal of Engineering Research (Kuwait), Vol. 11, no. 2, pp. 252-263.
Design of a distribution network for the school lunch program
(2023) Karadağ, Ayyüce Aydemir; Akdere, Erol; 116059
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.
Citation Count: Yıldırım, Gonca; Aydemir Karadağ, Ayyüce (2021). "DESIGNING AN ANNUAL LEAVE SCHEDULING POLICY: CASE OF A FINANCIAL CENTER", Journal of Industrial and Management Optimization.
DESIGNING AN ANNUAL LEAVE SCHEDULING POLICY: CASE OF A FINANCIAL CENTER
(2021) Yıldırım, Gonca; Aydemir Karadağ, Ayyüce; 45908; 116059
Providing annual leave entitlements for employees can help allevi-ate burnout since paid-time off work directly affects the health and productivity of workers as well as the quality of the service provided. In this paper, we de-velop realistic vacation scheduling policies and investigate how they compare from both the employer and the employees' perspectives. Among those poli-cies, we consider one that is used in practice, another that we propose as a compromise which performs very well in most cases, and one that is similar to machine scheduling for benchmarking. Integer programming models are for-mulated and solved under various settings for workload distribution over time, substitution and unit of time for vacations. We use three performance mea-sures for comparisons: penalty cost of unused vacation days, percent vacation granted and level of employee satisfaction. We provide a real-life case study at a bank's financial center. Numerical results suggest that an all-or-nothing type of vacation policy performs economically worse than the others. Attrac-tive annual leave scheduling policies can be designed by administering vacation schedules daily rather than weekly, ensuring full cover for off-duty employees, and offering employees some degree of choice over vacation schedules.
Citation Count: Yılmaz, Z.; Aydemir Karadağ, Ayyüce; Erol, S. (2019). "Finding optimal depots and routes in sudden-onset disasters: An earthquake case for Erzincan", Transportation Journal, Vol. 58, No. 3, pp. 168-196.
Finding optimal depots and routes in sudden-onset disasters: An earthquake case for Erzincan
(2019) Yılmaz, Z.; Aydemir Karadağ, Ayyüce; Erol, S.; 116059
This article focuses on determining the best routes between affected areas and relief depots in sudden-onset disasters and selecting the best depot that can serve at the shortest response time. These decisions are crucial in emergency humanitarian logistics management since the response time to affected areas dramatically influences the survival rate and timely availability of relief items. This article considers many real-life aspects to deal with the problem realistically. A framework based on Geographic Information System (GIS) is presented that takes into account widths and structures of different types of infrastructure (roads, tunnels, and bridges), the survivability of infrastructure according to its spatial proximity to a potential disaster, and legal speed limits in the pre- and post-disaster decision processes. A case study was carried out for an earthquake disaster scenario in Erzincan province of Turkey and various scenarios were generated to analyze the solutions under different conditions.
Citation Count: Aydemir Karadağ, Ayyüce (20199. "Katı Atık Depolama Tesisi Yer Seçimi için Birleştirilmiş Hedef Programlama ve AHP Yaklaşımı/A Combined Goal Programming and AHP Approach for Solid Waste Landfill Site Selection, International Journal of Engineering Research and Development, Vol. 11, No. 1, pp. 211-215.
Katı Atık Depolama Tesisi Yer Seçimi için Birleştirilmiş Hedef Programlama ve AHP Yaklaşımı
(2019) Aydemir Karadağ, Ayyüce; 116059
Tüm dünyada, nüfus ve kentleşmenin artması ve gelişen teknoloji ile beraber üretilen atık miktarı da artmaktadır. Katı atıkların bertarafı, büyük oranda düzenli depolama yöntemiyle sağlanmaktadır. Bir düzenli depolama sahasının uygun şekilde projelendirilmesi ve işletilmesi için en önemli ön şart uygun kuruluş yeri seçiminin yapılmasıdır. Sağlıklı, verimli, uzun ömürlü, sürdürülebilir ve yasal düzenlere uygun düzenli depolama yer seçimi çok kriterli bir karar problemidir. Bu çalışmada; Ankara ili ve çevresinde kurulabilecek katı atık düzenli depolama tesisi kuruluş yeri alternatifleri, çevresel, ekonomik, sosyal ve zeminsel kriterler açısından Analitik Hiyerarşi Prosesi (AHP) ile değerlendirilmiştir. Ankara'nın yıllık depolanan atık talebini karşılayacak alternatiflerin arasından seçim yapılması, AHP ile hesaplanan kriter ağırlıklarını ve alternatif önceliklerini kullanan ve sistem gerçeklerini yansıtan hedef programlama (HP) modeli ile sağlanır.

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