Yazar "Daş, G. Sena" seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • [ X ]
    Öğe
    A Stochastic Bilevel Programming Model for an Industrial Symbiosis Network
    (Springer Science and Business Media Deutschland GmbH, 2024) Daş, G. Sena; Yeşilkaya, Murat; Altinkaynak, Büşra; Birgören, Burak
    A stochastic bilevel model for an industrial symbiosis (IS) network in an eco-industrial park (EIP) is presented in this paper. Companies in IS networks produce final products using mostly by-products rather than raw materials. Companies in these networks are known to share a variety of synergies, including wastes and by-products. They mostly negotiate on the price and amount of the by-products. This negotiation is critical as by-products should be available on time at the right amount for smooth production. Moreover, the use of these by-products should provide savings compared to the use of raw materials so that companies could benefit from IS. However, the fluctuations in the final product demand affect both the EIP management (the leader) and companies (followers) in the network. Therefore, we proposed a stochastic bilevel model where the lower-level problem is a two-stage stochastic programming model. Our findings show that the demand uncertainty has an impact on both parties. © 2024, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
  • Küçük Resim
    Öğe
    Bir İletişim Uydu Operatörünün Fırlatma Aracı Seçim Problemi İçin Kesin ve Bulanık VZA Yaklaşımlarının Karşılaştırılması
    (2017) Daş, G. Sena; Tetik, Taha
    Uzay endüstrisinde, bir uydu için fırlatma aracı seçimi kritik bir idari ve teknik karar verme problemidir. Seçilen fırlatma aracına bağlı olarak fırlatma maliyeti, milyon dolarlık bir uydunun toplam maliyetinin yüzde 20'si ila 50'si arasında değişebilir. Bu çalışmanın amacı, istenilen yörüngeye bir yere eş zamanlı iletişim uydusunu fırlatmak için kullanılan fırlatma aracı alternatiflerini, Çok Kriterli Karar Verme (ÇKKV) yöntemleri kullanarak analiz etmektir. Bu amaçla, kesin ve bulanık Veri Zarflama Analizi (VZA) yönteminin versiyonları ÇKKV yöntemi olarak kullanılmıştır. Fırlatma aracı seçeneklerinin değerlendirilmesi için sektör uzmanları tarafından oluşturulan kriterler hiyerarşisi kullanılmıştır. Kesin ve bulanık VZA yöntemlerinin çıktıları kıyaslanmıştır. Kıyaslama sonucunda VZA versiyonlarının, seçenekleri farklı sıraladıkları ama Seçenek 1'in genellikle sıralamanın ilk sırasında yer aldığı gözlenmiştir
  • [ X ]
    Öğe
    Improving Distance Education in the COVID-19 Pandemic with Quality Function Deployment
    (Kırıkkale Üniversitesi, 2021) Daş, G. Sena; Türker, Ahmet Kürşad; Aktepe, Adnan; Ay, Nilay; Alıcı, İrem
    The purpose of this research is to evaluate how the distance education system can be improved by taking into account the feedback received from students who have experienced distance education during the COVID-19 pandemic. In this context, a questionnaire was designed to collect data about the socio-demographic characteristics of the students, their thoughts about the platform where distance education is held, their thoughts about the courses and exams made with distance education, and their views on distance education. 162 Industrial Engineering students who continued their undergraduate education remotely in the 2020-2021 Spring semester participated in the survey. The results showed that 64.2% of the students believed that distance education is not as efficient as face-to-face education. Quality Function Deployment technique has been applied to identify potential improvements that can be made in the distance education system. The results have shown that several improvements are necessary to improve the current system. Accordingly, it has emerged that several improvements should be done in order to provide interactive teaching, diversify course resources, and eliminate sources of ambiguities during the exam practice.