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Yayın Tractable supply chain production planning, modeling nonlinear lead time and quality of service constraints(Elsevier Ltd, 2007) Anlı, Osman Murat; Caramanis, Michael C.; Paschalidis, Ioannis Ch.This paper addresses the task of coordinated planning of a supply chain (SC). Work in process (WIP) in each facility participating in the SC, finished goods inventory, and backlogged demand costs are minimized over the planning horizon. In addition to the usual modeling of linear material flow balance equations, variable lead time (LT) requirements, resulting from the increasing incremental WIP as a facility's utilization increases, are also modeled. In recognition of the emerging significance of quality of service (QoS), that is control of stockout probability to meet demand on time, maximum stockout probability constraints are also modeled explicitly. Lead time and QoS modeling require incorporation of nonlinear constraints in the production planning optimization process. The quantification of these nonlinear constraints must capture statistics of the stochastic behaviour of production facilities revealed during a time scale for shorter than the customary weekly time scale of the planning process. The apparent computational complexity of planning production against variable LT and QoS constraints has long resulted in MRP-based scheduling practices that ignore the LT and QoS constraints has long resulted in MRP-based scheduling practices that ignore the LT and QoS impact to the plan's detriment. The computational complexity challenge was overcome by proposing and adopting a time-scale decomposition approach to production planning where short-time-scale stochastic dynamics are modeled in multiple facility-specific subproblems that receive tentative targets from a deterministic master problem and return statistics to it. A converging and scalable iterative methodology is implemented, providing evidence that significantly lower cost production plans are achievable in a computationally tractable manner.Yayın Optimal investment levels to eliminate inventory inaccuracy in a two-level supply chain(Istanbul Technical Univ, 2007) Uçkun, Canan; Karaesmen, Ahmet Fikri; Savaş, SelçukInventory inaccuracy is a major problem in supply chains. RFID technology is anticipated to alleviate this problem at the expense of the required hardware and software investment. For a supply chain consisting of single supplier and multiple warehouses, we investigate the optimal levels of investment in order to decrease inventory inaccuracy. The analysis yields in-sights on the relative benefits of RFID implementation depending on factors such as demand and inaccuracy variability, financial parameters and supply chain structure.Yayın Investment in improved inventory accuracy in a decentralized supply chain(Elsevier Science BV, 2008-06) Uçkun, Canan; Karaesmen, Ahmet Fikri; Savaş, SelçukIt is known that inaccurate inventory records can lead to profit losses in a supply chain. Inventory records may not be correct due to various reasons such as transaction errors, misplacement, shrinkage, etc. In order to eliminate inventory inaccuracy, companies may invest in new information technologies such as radio frequency identification (RFID). In this paper, we consider a supply chain consisting of a retailer (distributor) and a supplier. We assume a single-period newsvendor-type setting where the retailer purchases the items from the supplier and distributes them to the regional warehouses. The paper focuses on the problem of finding the optimal investment levels that maximize profit by decreasing inventory inaccuracy. The optimal level of investment is examined both for the centralized and the decentralized systems under two scenarios: inventory sharing between the warehouses is allowed and not allowed. The coordination problem is also considered for both scenarios. Finally, several extensions of the model are considered: asymmetric warehouse parameters, demand and inventory inaccuracy correlation and imperfect RFID implementation.Yayın The impact of the COVID-19 pandemic on online grocery supply chain management: a case study in Istanbul(Gazi Üniversitesi, 2024-03) Javadi, Sonya; Keten, Olcay; Özer, Ali İhsan; Alkan, Remziye ZeynepThe COVID-19 pandemic has already crippled normal life all over the world. Its negative impact not only changed the human health system tragically but also disrupted the global economic system. One negative result was ended up in the global food supply chain. As the lockdown times have suspended the manufacturing and logistic activities, therefore, the customers have experienced unimaginable chaos in the shopping markets. Moreover, the purchasing habit of the consumers has remarkably changed compared to pre-pandemic. To meet this new demand pattern, many grocery retailers have tried to adapt to the new normal. While before COVID-19 offline grocery purchasing was popular, after the pandemic, online service got tremendous attention in market. In this study, online grocery supply chain management during the COVID-19 in Istanbul is considered. The aim is to find out how online grocery companies will serve more efficiently during the pandemics and which factors have more effect on the customer’s satisfaction. To do so, first, three popular grocery retailers in Istanbul were selected. Then, a related survey was designed to understand the consumer experience as doing online grocery shopping in COVID-19. Unsurprisingly, a result shows that 60% of the respondents did online shopping every 3-4 days in one week, and the delivery time is the most important factor for the customers. Then, the SWOT analyses were performed accordingly, and the related strategies were summarized. Finally, several managerial implications were given to may improve the company’s online services in COVID-19 and post COVID-19 in Turkey.Yayın Performance outcomes of supply chain management practices: evidence from Pakistan's fan manufacturing SMEs(University of Novi Sad, 2025-12-01) Akbay, Ümmühan; Hafeez, Muhammad SalmanThis study examines the impact of supply chain management practices on the organization’s marketing and financial performance. We present the results of a survey conducted with 100 Pakistani fan manufacturing firms. Statistical analysis reveals that the industry struggles with information sharing and joint operations within the supply chain. PLS-SEM analysis of the survey data shows that supply chain performance is significantly correlated with organizational performance. Both customer and supplier relationship management have positive and significant effects on the performance of the supply chain and the organization. However, the impact of customer relationship management is stronger as its path coefficient is greater. Additionally, although internal supply chain management also impacts both supply chain and organization performance positively, the impact is slightly short of being statistically significant. This study contributes to the supply chain management literature by providing empirical evidence from an understudied manufacturing sector from a developing country.
