Yazar "Erbayrak, Seda" seçeneğine göre listele

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    Determination of the Impact Damage Threshold Point of Composite Material Using Fuzzy-Base Taguchi Method
    (ACADEMIC PUBLICATION COUNCIL, PO BOX 17225, KHALDIYA 72453, KUWAIT, 2020) Erbayrak, Seda; Erbayrak, Engin
    In this study, the impact damage threshold point of composite materials was determined using the optimum design parameters obtained from the Fuzzy Based Taguchi Method (FBTM). It is known that both Taguchi and Fuzzy methods provide optimization of design parameters yet, in Taguchi method, optimization of design parameters is not sufficient in solving multi response optimization problem. Therefore, Fuzzy Logic system was combined with the Taguchi system for working out the multi-response optimization problem. In this study, the low velocity impact damage analyses were performed in an LS-DYNA 3D explicit finite element program. ASTM D7136/D7136M standard was used during the low velocity impact analyses. In explicit finite element analyses, contact algorithms were executed to observe better damage zone shapes. Furthermore, the control parameters (termination and computation time step) were tuned to provide perfect correlation with the force-energy-time histories. The study concluded that Fuzzy Based Taguchi Method (FBTM) is much more capable of optimizing the design parameters that predict the impact damage threshold point of the composite material.
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    İstanbul İlinde Çalışma Hayatındaki Mesleki Gerilim ve Stresin Araştırılması
    (İstanbul Gelişim Üniversitesi Yayınları / Istanbul Gelisim University Press, 2023) Çakar, Tarık; Gülseven, Berkay; Barışkan, Mehmet Ali; Erbayrak, Seda
    Bu çalışmanın amacı İstanbul’da çalışma hayatındaki iş stresini ölçmek ve nedenlerini belirlemektir. Amaç aşağıda sıralanan 5 farklı soruya cevap bulmaktır; (1) İstanbul ilinde iş stresi ile ilgili gerçekler nelerdir? (2) Psikososyal risk değerlendirmesi ve stresten korunmak için hangi legal çerçeve ve ulusal altyapı mevcuttur? (3) İşveren organizasyonları ve ticari birliklerin iş stresi ile ilgili olarak görüşleri ve değerlendirmeleri nelerdir? (4) İş stresi ve psikososyal risklerin ölçülmesi ve değerlendirilmesi için hangi enstrümanlar kullanılmaktadır? (5) İşletmeler iş stresini azaltmak için hangi koruyucu önlemleri almaktadırlar? Çalışma her bir işletmeden 2-4 kişi seçilerek 45 farklı işyerinde yapılacaktır. Hazırlanan anket toplamda 132 kişiye uygulanacaktır. Bu çalışmanın sonunda, ülke gerçekleri göz önüne alınarak devletin iş stresinden korunma konusundaki rolü belirlenecektir. Ek olarak, stres koruma programlarının geliştirilmesi ile ilgili ne gibi çalışmalar yapılabileceği ortaya konacak ve belli bölgelerde stres yönetim merkezleri oluşturulması yönünde tavsiyelerde bulunulacaktır.
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    Multi-objective 3D bin packing problem with load balance and product family concerns
    (PERGAMON-ELSEVIER SCIENCE LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND, 2021) Erbayrak, Seda; Özkır, Vildan; Yıldırım, Umman Mahir
    The classical three-dimensional bin packing problem (3D-BPP) orthogonally packs a set of rectangular items with varying dimensions into the minimum number of three-dimensional rectangular bins. While ensuring the minimum number of bins used, the safety of the logistic operations is addressed with the complementary loadbalancing objective for which concepts such as orientation and stability are used in the literature though not at the same time. In this study, we extend the load-balanced 3D-BPP by combining both orientation and stability, and introducing a new concept called family unity which encourages packing a family of products (e.g., from the same order and with the same destination) together. Although item related concerns are very common in practice, there are no multi-objective studies in the bin packing literature that includes family unity concept. Therefore, this is the first study that proposes a multi-objective mixed integer programming model for the extended problem to determine the optimal packing plan that minimizes the number of bins used and the deviation of balance from the ideal barycenter while maximizing family unity ratio via a weighted objective function. A numerical example is provided to analyze the performance of the proposed model. Furthermore, a real-life container loading problem is solved and outputs of the study implies the practical advantages of including family unity and load-balance considerations in solving 3D-BPP problems.