Browsing by Author "Turhanlar, Ecem Eroglu"

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Citation - WoS: 32
Citation - Scopus: 52
Additive manufacturing integration in E-commerce supply chain network to improve resilience and competitiveness
(Elsevier B.V., 2023) Banu Yetkin Yetkin Ekren; Nikolaos D. Stylos; Jeremy Zwiegelaar; Ecem Eroğlu Turhanlar; Vikas Kumar; Stylos, Nikolaos; Turhanlar, Ecem Eroglu; Zwiegelaar, Jeremy; Kumar, Vikas; Ekren, Banu Yetkin
In light of recently increased e-commerce also a result of the COVID-19 pandemic this study examines how additive manufacturing (AM) can contribute to e-commerce supply chain network resilience profitability and competitiveness. With the recent competitive supply chain challenges companies aim to decrease cost performance metrics and increase responsiveness. In this work we aim to establish utilisation policies for AM in a supply chain network so that companies can simultaneously improve their total network cost and response time performance metrics. We propose three different utilisation policies i.e. reactive proactive – both with 3D printing support – and a policy excluding AM usage in the system. A simulation optimisation process for 136 experiments under various input design factors for an (s S) inventory control policy is carried out. We also completed a statistical analysis to identify significant factors (i.e. AM holding cost lead time response time demand amount etc.) affecting the performance of the studied retailer supply chain. Results show that utilising AM in such a network can prove beneficial and where the reactive policy contributes significantly to the network performance metrics. Practically this work has important managerial implications in defining the most appropriate policies to achieve optimisation of supply network operations and resilience with the aid of AM especially in times of turbulence and uncertainty. © 2022 Elsevier B.V. All rights reserved.
Aisle-to-aisle design for SBS/RS under smart deadlock control policies
(IEOM Society, 2021) Ecem Eroğlu Turhanlar; Banu Yetkin Yetkin Ekren; Tone Lerher; Lerher, Tone; Turhanlar, Ecem Eroglu; Ekren, Banu Yetkin
Recent increase in e-commerce warehouse operations have become one of the most significant issues. Recent customer profile requests fast delivery time with flexible options in purchasing. Automated warehousing technologies are widely utilized in warehouses to provide fast solutions for those demand profiles. Shuttle-based storage and retrieval system (SBS/RS) is an automated warehousing technology assuring fast transaction process in warehouses. In this work we study a special design for SBS/RS where automated vehicles (i.e. shuttles) are more flexible in their travel pattern so that the system would not require a dedicated shuttle in each tier resulting with decreased number of shuttles compared to a dedicated one (i.e. each zone with a single shuttle) in the system. We compare these two system designs flexible and dedicated ones by using an agent-based simulation modelling approach. The proposed flexible design is developed on deadlock and collision prevention algorithms evaluating real time information. The performance of the system is compared by their average flow time per transaction maximum flow time of a transaction throughput rate and utilization of shuttles etc. The results show that by integrating smart collision and deadlock prevention algorithms the proposed flexible aisle-to-aisle SBS/RS works better than the dedicated system design. © 2021 Elsevier B.V. All rights reserved.
Citation - WoS: 21
Citation - Scopus: 26
Autonomous mobile robot travel under deadlock and collision prevention algorithms by agent-based modelling in warehouses
(TAYLOR & FRANCIS LTD, 2024) Ecem Eroglu Turhanlar; Banu Y. Ekren; Tone Lerher; Lerher, Tone; Turhanlar, Ecem Eroglu; Ekren, Banu Y.
Recent dramatic increase in e-commerce has also increased the adoption of automation technologies in warehouses. Autonomous mobile robots (AMRs) are from those technologies widely utilized in warehouse operations. It is important to design the operation of those robotic systems in such a way that they meet the current and future system requirements correctly. In this paper we study flexible travel of AMRs in warehouses by developing smart deadlock and collision prevention algorithms on agent-based modelling. By that AMR agents can interact with each other and environment so that they can make smart decisions maximizing their goals. We compare the performance of the developed flexible travel system with non-flexible designs where there is a single AMR dedicated to a specific zone so that no deadlock or collision possibility takes place. The results show that AMRs may provide up to 39% improvement in the flexible system compared to its non-flexible design.
Deadlock and Collision Prevention Algorithms for Mobile Robots in Automated Warehouses
(IEOM Society, 2021) Ecem Eroğlu Turhanlar; Banu Yetkin Yetkin Ekren; Turhanlar, Ecem Eroglu; Ekren, Banu Yetkin; M. Fargnoli , M. Lombardi , M. Tronci , P. Dallasega , M.M. Savino , F. Costantino , G. Di Gravio , R. Patriarca
Recent supply chain targets have led to decreased response time requests also causing enterprises invest for automation technologies for efficient management for their warehouses. In this paper we focus on an automated warehousing environment where there are robotic order pickers travelling on ground flexibly throughout aisles. We develop deadlock and collision prevention algorithms for safely travel of those robotic order pickers. The developed algorithms can be utilized by any warehouse system having autonomous vehicles (e.g. automated guided vehicles mobile robots or shuttles in a multi-tier automated warehouse) that can travel between aisles freely. While developing those smart algorithms we also aim to improve some performance metrics such as average flow time and maximum flow time of a transaction in the system. To test the performance of the algorithms we model the system as a multi-agent system where autonomous vehicles are able to communicate with each other under an Internet of Things (IoT) environment. We compare that flexible system design with a dedicated design where a dedicated vehicle is assigned for a predefined number of aisles. The experimental results show that under well-designed deadlock and collision prevention control algorithm flexible travel of vehicles can provide advantage compared to dedicated design. © 2022 Elsevier B.V. All rights reserved.
Citation - WoS: 56
Citation - Scopus: 66
Lateral inventory share-based models for IoT-enabled E-commerce sustainable food supply networks
(Elsevier Ltd, 2021) Banu Yetkin Yetkin Ekren; Sachin Kumar Kumar Mangla; Ecem Eroğlu Turhanlar; Yigit Kazancoglu; Guo Li; Turhanlar, Ecem Eroglu; Li, Guo; Mangla, Sachin Kumar; Kazancoglu, Yigit; Ekren, Banu Yetkin
This research investigates lateral inventory share-based business models for e-grocery networks where online groceries are inter-connected in an Internet of Things (IoT) environment. Recently managing food supplies has become a very important issue due to the onset of unexpected conditions such as natural disasters (earthquakes tsunamis floods droughts etc.) and pandemics. In this paper we aim to design sustainable food supply chain networks for e-commerce food companies (e.g. e-groceries) by applying lateral inventory share policies after the consideration of the existence of strategic alliances between organizations. We aim to minimize food waste as well as back orders resulting in more sustainable networks. Further we explore how a business-to-business (B2B) policy (i.e. lateral-inventory share policy) should be designed to optimize business (i.e. e-groceries) profitability. We optimize the re-order and up-to (sS) inventory levels of e-groceries for the pre-defined sharing policies by using a simulation optimization approach. The optimal results show that having a lateral inventory share poliIndiacy in food networks is more efficient compared to a non-lateral policy. Also at the optimal points of the considered policies lateral inventory share ratio is usually observed to be larger than 50% on average meaning that more than half of customer orders are met by lateral inventory share. © 2021 Elsevier B.V. All rights reserved.