Endüstri Mühendisliği Bölümü Yayın Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/279
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Conference Object Forecasting Day of Week Volume Fluctuations in the Intermodal Freight Transportation(Institute of Industrial Engineers, 2011) Ertem, M.A.; Ertem, Mustafa Alp; Endüstri MühendisliğiAverage daily volume fluctuates intensely based on the day of week in the intermodal freight transportation. Shippers tend to peak around Thursdays and receivers tend to peak around Mondays. These fluctuations bring challenges to the industry in terms of capacity management and getting reliable service from the railroad companies. The purpose of this study is to forecast J. B. Hunt Transport Services, Inc.'s load volume on railroads. Load is meant to be the number of containers that will arrive at a rail ramp during a 24hrs time window. The end in mind is to have better service from the railroad companies and to manage the company owned equipment better. The forecasting model applied to tackle this problem is a multiple linear regression model and is based on the historical in-gate numbers. It uses the previous two year's data and day of week information as independent variables, and current year's data as the response variable. The results indicate better accuracy levels for the model when compared to the two week moving average.Article Citation - WoS: 7Citation - Scopus: 11A Warehouse Design With Containers for Humanitarian Logistics: A Real-Life Implementation From Turkey(Univ Cincinnati industrial Engineering, 2019) Sahin-Arslan, Aysenur; Ertem, Mustafa Alp; Ertem, Mustafa Alp; Endüstri MühendisliğiThe purpose of this study is to investigate how and at what cost freight containers could be used as an inventory holding mechanism for humanitarian logistics. The layout and cost comparison of two alternatives are performed-stocking in a warehouse and material storage in containers. An optimum layout for storage in containers is proposed. It was found that container stockpiling uses the available area and space better than the warehouse option to stock the same number of material pallets. Leasing and purchasing costs of these alternatives are compared using present worth analysis. The results revealed that the container leasing option is not cost effective when land cost is included. Warehouse leasing results in the least setup cost, however, it incurs more operating costs, including lighting, ventilation, and maintenance as well as handling of the pallets. A real-life implementation of the proposed container stockpiling idea is presented for Turkey.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.Book Part A Procurement Auctions-Based Framework for Coordinating Platforms in Humanitarian Logistics(2013) Ertem, Mustafa Alp; Buyurgan, NebilThis chapter focuses on an auction-based procurement framework for single coordinating platforms in humanitarian logistics. It first covers disaster relief operations, humanitarian logistics, and procurement in this context and illustrate many of the issues that make the management and coordination of procurement functions complex and challenging. Then the proposed framework along with the auction model is discussed including the unique design characteristics associated with disaster relief environment. Three-phase approach presents a complete representation of the procurement in humanitarian logistics. Results indicate that the proposed announcement options increase the fill rate. Announcement construction criteria allow coordinating platforms to use varying bundling choices.Article Citation - WoS: 8Citation - Scopus: 9Intermodal Humanitarian Logistics Using Unit Load Devices(Springer Heidelberg, 2022) Kavlak, Hasan; Ertem, Mustafa Alp; Satir, BenhurIntermodal freight transportation facilitates today's global trade. The benefits of intermodal freight transportation have been studied and are more observable in commercial logistics; however, the potential benefits of humanitarian logistics have not been thoroughly investigated. This research aims to present a resilient transportation framework by modeling intermodal transportation utilizing interoperable loading devices during disaster responses. We developed an integer programming model based on a time-space network by considering route and vehicle availabilities that are allowed to change with time. We consider vehicles with varying capacities in three transportation modes (i.e., ground, maritime, and air). The contribution of this study is threefold: (1) Two compatible unit load devices are proposed for humanitarian logistics; (2) a mathematical model that includes integer variable representation for vehicle fleets in different transportation modes is developed; and (3) intermodal transportation is compared with single-mode transportation using a real-life dataset. Our main results are as follows: In terms of cost, intermodal transportation is effective when demand occurs in consecutive periods and response time is short. Inventory is held more in intermodal transportation when it is cost-effective to use transportation modes with large capacities. Thus, the benefits of the responsiveness of intermodal transportation outweigh the costs of mode interchange and inventory holding for sudden-onset disasters where quick responses are needed within a short time.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 İnsani Yardım Lojistiği için Konteyner Deposu Tasarımı(2019) Ertem, Mustafa Alp; Şahin Arslan, AyşenurArticle Citation - WoS: 30Citation - Scopus: 34An Auction-Based Framework for Resource Allocation in Disaster Relief(Emerald Group Publishing Ltd, 2011) Buyurgan, Nebil; Ertem, Mustafa Alp; Alp Ertem, MustafaPurpose - The purpose of this paper is to address the inefficiency problems in procurement operations in disaster relief logistics which are mainly due to the lack of coordination among less organized suppliers and partnerships. Such problems lead to poor responsiveness and hinder timely procurement of required goods. Design/methodology/approach - An auction-based framework for procurement of goods, which is suitable for a single coordinating platform in disaster relief logistics, is proposed. Integer programming formulations are used in auctioning operations. A simulation model that generates problem instances is used to evaluate and tune system-level design parameters. Findings - Design parameters greatly affect the behaviour and responsiveness of the system and the performance of the auction-based framework in different problem instances. Combinations of those parameters may allow suppliers with limited capacities to become more involved in the bidding process. In addition, the procurement shares of bidders may change substantially with different values of the parameters. Research limitations/implications - Even though the presented framework is inspired from reallife applications, it is not implemented in real-life disaster relief operations. The goodness of fit for the framework would best be evaluated by a real disaster case. In addition, transportation scheduling and vehicle routing considerations and budgeting issues are not considered in the framework. Originality/value - This paper presents an auction-based framework for less organized suppliers of goods and their partnerships, such as local humanitarian organizations, private companies, and standby partners. The presented framework offers a background for coordination during disaster relief operations which provides opportunities to act as a set of organized entities. This background also helps those entities coordinate their efforts to enhance the capabilities of local governments and NGOs.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: 31Citation - Scopus: 35Review of Intermodal Freight Transportation in Humanitarian Logistics(Springeropen, 2017) Arslan, Aysenur Sahin; Ertem, Mustafa Alp; Isbilir, Melike; Şahin Arslan, AyşenurPurpose Using intermodal transportation is vital for the delivery of relief supplies when single mode alternative becomes unusable or infeasible. The objective of this paper is to investigate the use of intermodal freight transportation in humanitarian logistics. Methods This paper first identifies the differences between multimodal and intermodal transportation. Then, we examine the use of each transportation mode for specific disaster types and phases. When combinations of transportation modes (i.e. air, road, rail and sea) for intermodal transportation are considered together with different disaster types (e.g. earthquake, flood and famine), the feasible decision space becomes rather large. To explore this decision space, we have reviewed the academic and practitioner studies as well as several non-governmental organizations (NGO)' disaster archives. Results From this exploration, we developed a transportation mode/disaster-type combination matrix and a transportation mode/disaster-phase combination matrix. We then discuss examples of real life usage of intermodal transportation in humanitarian logistics and share our findings and analyses. Of 369 academic humanitarian logistics articles, only 20 have mentioned transportation mode changes. In practitioner studies, we found a decreasing percentage of the usage of slower modes (e.g. sea and rail) in the disaster response phase over time. We were not able to find a significant relationship between a specific transportation mode and a specific disaster-type or - phase. Road transportation seems to cover most of the disaster operations regardless of the disaster-type or - phase. Conclusions We can conclude that intermodality and the transportation unit concept is not being studied extensively in humanitarian logistics. Most of the relief organizations do not share transported freight amounts in their reports and those that do share transported freight amounts in their reports do not explicitly mention mode changes. We discuss the enablers of and obstacles to the effective use of intermodal transportation in humanitarian logistics and propose future research directions. We anticipate that intermodal transportation in humanitarian logistics will garner greater research attention and increased utilization in coming years.