Endüstri Mühendisliği Bölümü Yayın Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/279
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Article Citation - WoS: 15Citation - Scopus: 22Intermodal Transportation in Humanitarian Logistics With an Application To a Turkish Network Using Retrospective Analysis(Elsevier, 2022) Akdogan, Muharrem Altan; Kahya, Melike; Ertem, Mustafa AlpIn the event of disruptions in a transportation network following a disaster, humanitarian organizations find it challenging to provide basic requirements for beneficiaries. Demand may be met using intermodal transportation as an alternative when the unimodal transportation infrastructure is damaged. This study proposes a mathematical model for utilizing intermodal transportation using 40 ft standard containers while delivering relief supplies by road, rail, and sea modes. The proposed model is a capacitated multi-period multicommodity intermodal network flow model in which relief supplies are delivered to beneficiaries in three echelons (i.e., supply, intermodal hub, and demand). The Turkish Disaster and Emergency Management Presidency's container warehouses (i.e., supply), logistics centers and container ports (i.e., intermodal hubs) are utilized to test the mathematical model with real-life demand parameters. Retrospective analysis was performed to determine the most frequently used container warehouses, logistics centers, and origin-destination pairs. Hence, an increase in operational capacity and infrastructure reinforcement is recommended to mitigate the effects of future disasters. We found that intermodal transportation is more robust to network disruptions in rapidly delivering relief supplies. We observed that intermodal transportation is utilized in disasters with more than 50,000 beneficiaries or disrupted unimodal infrastructure. For instance, after the future Istanbul earthquake, it would be impossible to deliver the relief materials only by road transportation within the urgent response period. Thus, the benefits of intermodal transportation in humanitarian logistics are more visible in large-scale disasters in which transportation resources are scarce, and transportation infrastructure is more likely to be destroyed.Article Citation - WoS: 17Citation - Scopus: 19Determination of Equivalent Warehouses in Humanitarian Logistics by Reallocation of Multiple Item Type Inventories(Elsevier, 2021) Ertem, Mustafa Alp; Demirbas, SefikaPrepositioning freight containers for storage of relief supplies can be considered an alternative to warehousing with shelves. Recently, 25 container warehouses are located in different cities in Turkey to deliver relief supplies to beneficiaries quickly. We take this existing situation as given and investigate if this investment could be utilised better. The available inventory (i.e., tents, beds, blankets) in these container warehouses is currently not used efficiently. Some warehouses store one type of item and none from other types. Therefore, several warehouses must be activated during a response operation to fully satisfy the beneficiaries' needs for each relief item type. We aim to investigate the benefits of operating equivalent (i.e., a proper inventory level from each relief item type) warehouses while reallocating a total available inventory for better coordination. A locationreallocation type of mathematical model is tested with real-life data from past earthquakes. Three to eight container warehouses are recommended to be converted to an equivalent type. The results indicate potential savings for the proposed model, and this potential is more visible in large-scale demand instances than in small ones.Conference Object Citation - WoS: 300Citation - Scopus: 368Models, Solutions and Enabling Technologies in Humanitarian Logistics(Elsevier Science Bv, 2015) Ertem, Mustafa Alp; Ozdamar, LinetWe present a survey that focuses on the response and recovery planning phases of the disaster lifecycle. Related mathematical models developed in this area of research are classified in terms of vehicle/network representation structures and their functionality. The relationships between these characteristics and model size are discussed. The review provides details on goals, constraints, and structures of available mathematical models as well as solution methods. In this review, information systems applications in humanitarian logistics are also surveyed, since humanitarian logistics models and their solutions need to be integrated with information technology to enable their use in practice. (C) 2014 Elsevier B.V. All rights reserved.Article Citation - WoS: 42Citation - Scopus: 49Pre-Positioning of Relief Items in Humanitarian Logistics Considering Lateral Transhipment Opportunities(Elsevier Science inc, 2017) Ertem, Mustafa Alp; Duran, Serhan; Baskaya, SerhatThe main objective of this study is to investigate the inclusion of lateral transhipment opportunities into the humanitarian relief chain and to examine the effect of different parameters on minimizing the average distance travelled per item while serving the beneficiaries. Direct shipment model (DT), lateral transhipment model (LTSP) and maritime lateral transhipment model (MLTSP) are developed and compared between each other by using a real life earthquake scenario prepared for the city of Istanbul by JICA (Japanese International Cooperation Agency). Developed mathematical models decide on the locations and number of disaster relief facilities, quantity of relief items to hold at those facilities, and quantity of lateral transhipment between the facilities. Vulnerability of the roads and heterogeneous capacitated facilities are also considered. It can be concluded that both LTSP and MLTSP models gave better results than DT model and lateral transhipment option helps beneficiaries to obtain relief items faster and with higher service level. (C) 2016 Elsevier Ltd. All rights reserved.Article Citation - WoS: 30Citation - Scopus: 38Intermodal Humanitarian Logistics Model Based on Maritime Transportation in Istanbul(Springer, 2016) Aygunes, Haluk; Ozkapici, Dilsu Binnaz; Ertem, Mustafa AlpIstanbul, the economic capital and most populated city of Turkey, is highly prone to earthquakes. When an earthquake occurs, required relief items are expected to be supplied from national and international sources. To alleviate human suffering following an earthquake, in this paper, we propose an intermodal relief item distribution model for Istanbul involving sea and land transportation with identified road vulnerabilities. The proposed mathematical model utilizes the seaports of Istanbul for maritime transportation and allows for the transportation of relief item between Istanbul's European and Anatolian sides. We also use the seabasing concept for providing supplies to demand areas. The use of maritime transportation and seabasing provides flexibility for humanitarian logistical activities and the proposed model provides an effective and reliable disaster relief system for Istanbul as well as other disaster-prone cities with significant maritime transportation components.