Browsing by Author "Kandemir, Cansu"

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Impacts of Supply Chain Design Parameters on Retailer In-Store Logistics Performance
(İzmir Ekonomi Üniversitesi, 2012) Kandemir, Cansu; Demir, Muhittin Hakan
Günümüzün karmaşık tedarik zinciri yapısı ve perakende sektöründeki rekabet nedeniyle perakendeciler faaliyetlerini geliştirmek için yoğun çaba harcamaktadırlar. Yeni iş ortamının dayattığı koşullar altında, müşteri hizmet düzeyleri, mağaza gelirleri, stok maliyetleri ve stok dışı olma durumu gibi performans parametrelerini doğrudan etkilemesi nedeni ile, tedarik zincirinin son birkaç metresi gitgide daha önemli hale gelmektedir. Bu nedenle şirketler mağazalarını, dolayısı ile mağaza lojistiğini daha verimli hale getirmek için çeşitli yollar aramaktadırlar. Geleneksel yaklaşımlar mağaza lojistiğinin içsel yönetim dinamikleri üzerine yoğunlaşmaktadır. Bu çalışmada, probleme daha geniş bir perspektif ile bakılmaktadır. Tedarik zinciri yapısal parametreleri ve mağaza lojistiği arasındaki etkileşimi sorgulanmaktadır. Bunu yaparken, talepler, envanter yönetimi politikaları, stok yenileme aralıkları ve dağıtım merkezi kapasitesi gibi tedarik zinciri yapısal parametrelerinin yanısıra, raf doldurma rejimleri, raf kapasitesi, stok kontrolü politikaları, gibi mağaza içi lojistiği operasyonel parametrelerinin de tedarik zinciri bütününün performansına etkilerini tespit etmeyi amaçlıyoruz. Çalışmaya, tedarik zinciri yapısı ve parametrelerini tanımlayarak başlıyoruz. Daha sonra analitik araç olarak benzetim yöntemini kullanılmaktadır. Çalışmada Arena Benzetim Paketi Yazılımı versiyon 13.9 kullanılmıştır.
Citation - WoS: 27
Citation - Scopus: 34
Modeling Turkey's Future Lng Supply Security Strategy
(Elsevier Sci Ltd, 2012) Biresselioglu, Mehmet Efe; Demir, Muhittin Hakan; Kandemir, Cansu
Turkey was among those countries which decided to increase its natural gas consumption in the 19905, due to its relative low cost and lack of impact on the environment. However, a heavy dependence on imports, from Algeria, Qatar and Nigeria, respectively, creates a threat to energy security, both in terms of source and supply diversity. Accordingly, we follow an analytical approach to identify the accuracy of our assumption, considering the current economic, political and security risk. To this end, we formulate and solve a mixed integer programming model that determines the optimal sourcing strategy for Turkey's increasing LNG demand. This model demonstrates a number of alternative policy options for LNG supply. Furthermore, we consider that increasing the proportion of LNG in the overall gas supply will contribute to the aim of improving Turkey's level of energy security. (C) 2012 Elsevier Ltd. All rights reserved.
Nöbetçi Eczane Çizelgeleme Problemleri
(2014) Kocatürk, Fatih; Kandemir, Cansu; Özdemirel, Aybike; Özpeynirci, Nail Özgür; Ceylan, Gökhan
[Abstract Not Available]
Citation - WoS: 4
Citation - Scopus: 5
A Pseudo-Polynomial Time Algorithm for a Special Multiobjective Order Picking Problem
(World Scientific Publ Co Pte Ltd, 2015) Özpeynirci, Özgür; Kandemir, Cansu
In this study, we work on the order picking problem (OPP) in a specially designed warehouse with a single picker. Ratliff and Rosenthal [Operations Research 31(3) (1983) 507-521] show that the special design of the warehouse and use of one picker lead to a polynomially solvable case. We address the multiobjective version of this special case and investigate the properties of the nondominated points. We develop an exact algorithm that finds any nondominated point and present an illustrative example. Finally we conduct a computational test and report the results.
Citation - WoS: 6
Citation - Scopus: 7
Work Process Improvement Through Simulation Optimization of Task Assignment and Mental Workload
(Springer, 2019) Kandemir, Cansu; Handley, Holly A. H.
The outcome of a work process depends on which tasks are assigned to which employees. However, sometimes optimized assignments based on employees' qualifications may result in an uneven and ineffective workload distribution. Likewise, an even workload distribution without considering the employee's qualifications may cause unproductive employee-task matching that results in low performance. This trade-off is even more noticeable for work processes during critical time junctions, such as in military command centers and emergency rooms that require fast, effective and error free performance. This study evaluates optimizing task-employee assignments according to their capabilities while also maintaining a workload threshold. The goal is to select the employee-task assignments in order to minimize the average duration of a work process while keeping the employees under a workload threshold to prevent errors caused by overload. Due to uncertainties related with the inter-arrival time of work orders, task durations and employees' instantaneous workload, a simulation-optimization approach is required. A discrete event human performance simulation model was used to evaluate the objective function of the problem coupled with a genetic algorithm based meta-heuristic optimization approach to search the solution space. A sample work process is used to show the effectiveness of the developed simulation-optimization approach. Numerical tests indicate that the proposed approach finds better solutions than common practices and other simulation-optimization methods. Accordingly, by using this method, organizations can increase performance, manage excess-level workloads, and generate higher satisfactory environments for employees, without modifying the structure of the process itself.