Person: DEMİREL, DUYGUN FATİH
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Dr. Öğr. Üyesi
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DEMİREL
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DUYGUN FATİH
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Publication Restricted Analyzing the Wastewater Treatment Facility Location/Network Design Problem via System Dynamics: Antalya, Turkey Case(Academic Press Ltd. - Elsevier Science Ltd., 2022) DEMİREL, DUYGUN FATİH; Gönül-Sezer, Eylül Damla; Pehlivan, Seyda AlperenWastewater treatment facility location selection and network design issues have become attractive topics in the field of wastewater management due to increasing human population, resource scarcity, environmental concerns, and rise of necessity for sustainable solutions for future policy designs. Especially in areas where the demand for wastewater treatment increases dramatically over the years because of reasons such as high migration levels, rapid industrialization, and tourism activities, the problem turns out to be more critical and dynamic. The existing studies try to deal with the issue through mathematical modeling approaches based on optimization perspectives, which require significant computational effort. In this study, an alternative approach based on system dynamics (SD) method is proposed to examine the complex dynamic and nonlinear structure of waste-water treatment facility location selection and network design problems. The proposed SD simulation model is designed for a densely populated industrial and tourism spot, the city of Antalya, located on the Mediterranean coast of Turkey. The model is capable of determining where and when to build a new wastewater treatment facility as well as generating the generic wastewater network structure to be built for the five districts situated in the city center based on cost issues for 2015-2040 period. In addition, the impacts of demand level changes for wastewater treatment due to population variations are analyzed via several scenarios to help decision makers to develop sustainable and cost-efficient management policies. Although SD is a frequently utilized approach in the water/wastewater management arena, to the best of our knowledge, this study is the first attempt to examine the complex and dynamic nature of wastewater treatment facility location selection and network design problems through SD approach.Publication Unknown Examining the Impacts of Military Expenditures on Economic Productivity: A System Dynamics Approach(SAGE Publications Ltd., 2023) Damla Gönül-Sezer, Eylül; DEMİREL, DUYGUN FATİHThe relationship between military expenditures and economic productivity has taken the attention of many researchers and there exist an important number of studies approaching the topic through several techniques. However, there is no consensus among the scholars whether military expenditures trigger economic growth, productivity, and other macroeconomic indicators. Such arguments are mainly due to unclear results obtained from the existing studies, in which the complex relationships between military expenditures and macroeconomics are not fully incorporated. Considering the bidirectional and nonlinear relationships among macroeconomic indicators and complex feedback mechanisms, a system dynamics (SD) model for examining the impacts of military expenditures on economic productivity in Turkey is proposed. The proposed SD model aims to reflect the complex environment surrounding the military spending–economic productivity nexus and to analyze the feedback structures that lead to miscellaneous consequences with delays. A stock–flow model is developed to represent the complex nonlinear relationships and causalities between the variables. Data from SIPRI, the World Bank, and several local statistical sources covering the years 2009–2018 are utilized to simulate the existing case, warfare in neighbors, economic shrinkage scenarios, and the combination of the latter two. The results obtained from the scenarios suggest that short fixes such as importing military products instead of national investments give rise to chronic issues like continual dependence on foreign supply, hence, leading to decrease in overall economic growth. To the best of our knowledge, this is the first attempt to integrate SD methodology with military expenditure and economic productivity analysis.Publication Open Access Marmara Denizi'nde Görülen Müsilajın Ortadan Kaldırılmasına Yönelik Politikaların Sistem Dinamiği İle İncelenmesi(Kahramanmaraş Sütçü İmam Üniversitesi, 2024) DEMİREL, DUYGUN FATİH; Sezer, Eylül Damla GönülJeopolitik, ekonomik ve ekolojik açıdan önemli bir yeri olan Marmara Denizi’nde yaşanan kirlilikteki artış son yıllarda farklı çevrelerin dikkatini çekmekle birlikte özellikle 2020-2021 yıllarında yaşanan müsilaj problemi sorunun ciddiyetini ortaya koymuştur. Literatürde iklim değişikliği, topografik yapı, artan nüfus, sanayileşme, tarım aktiviteleri, atıksu arıtma sistemlerinde kullanılan teknolojinin yetersizliği, vb. etmenlerin müsilaj oluşumunu tetiklediği öne sürülmektedir. Müsilaj sorununun çözümüne yönelik çeşitli stratejiler öne sunulmakla birlikte bu stratejilerin ne gibi sonuçlar doğuracağına ilişkin sayısal bir çalışma bulunmamaktadır. Bu amaçla bu makalede Marmara Denizi’nde görülen müsilaj olgusunu modellemek ve sorunu çözmeye yönelik politikaların etkilerini incelemek üzere sistem dinamiği yaklaşımına dayalı bir benzetim modeli sunulmaktadır. Önerilen model müsilaja neden olan temel mekanizmalar ile müsilajın ekonomik etkilerini temsil etmekte olup müsilaj problemini ortadan kaldırmaya yönelik çeşitli stratejilerin etkinlik seviyelerini farklı senaryolarla ortaya koymaktadır. Elde edilen bulgulara göre ileri biyolojik arıtma seviyelerinin arttırılması, tarım ve hayvancılık aktiviteleri için alınacak önlemler ve bölge nüfus artışına karşı alınacak önlemlerin bir arada uygulanmasının Marmara Denizindeki müsilaj riskini sınırlandıracağı sonucuna varılmaktadır.Publication Unknown Examining the Effects of Forest Fires: A Framework for Integrating System Dynamics and Remote Sensing Approaches(IGI Global, 2024) Eriş, Müjgan Bilge; DEMİREL, DUYGUN FATİH; Sezer, Eylül Damla GönülForest fires have been a major concern for many countries over an extended period of time due to natural and human induced factors. In recent years, detection of forest fires has progressively shifted toward advanced technologies where the remote sensing approaches are fully operational. To enhance fire management strategies, it is crucial to gain a comprehensive understanding of the fire dynamics and its consequences on the environment, operational sources, and economic sectors. Therefore, this chapter develops an integrated framework to predict and analyze the effects of forest fires by using system dynamics approach and remote sensing technology, ultimately leading to the establishment of a conceptual model and conclusive insights. © 2024, IGI Global. All rights reserved.Publication Unknown Determining a New Warehouse Location for an Electrical Home Appliances Company(Springer Science and Business Media Deutschland GmbH, 2024) KIZILKAYA, İLAYDA; KEVSER, TOLGAHAN; OFLUOĞLU, HANDE; ÖLÇÜCÜER, FEYZA; DEMİREL, DUYGUN FATİHIn today’s businesses, supply chain management is a critical factor in terms of efficiency, profitability and cost savings. The success of the supply chain is possible with the right management of the rings such as warehousing and logistics activities. Deficiencies in warehouse and logistics management can lead to inefficiencies and errors in the supply chain, which can have negative effects on business profitability and customer satisfaction. Strategic decisions regarding warehouse locations are vital for cost policies. In this study, a warehouse location selection procedure is proposed for an electrical home appliances company considering the distances to the customers, their transaction volumes, and various other costs. The approach is basically a two-stage facility layout problem that first solves a weighted Euclidean minisum model defined on a continuous plane. Then, four alternative locations that are close to the result obtained in the first step are determined. In addition, two lands owned by the firm are added to the set of alternatives. Next, a p-median (1-median) model is solved and the most suitable warehouse location is determined. Through sensitivity analysis, the changes in the solution are searched for various rent values. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.