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    DESIGNING REVERSE LOGISTICS NETWORK FOR END-OF-LIFE VEHICLES: A SUSTAINABILITY PERSPECTIVE IN A FRAGILE SUPPLY CHAIN
    (Univ Cincinnati Industrial Engineering, 2021) Ayvaz, Berk; Kusakci, Ali Osman; Aydin, Nezir; Ertas, Emine
    Environmental guidelines in the automotive industry greatly emphasize the recycling, remanufacturing, and recovering of end-of-life vehicles (ELVs). Given the principle of extended producer responsibility, developing an effective reverse logistics network is the most significant digit ahead of the industry. However, initial attempts addressing the reverse logistics network design (RLND) problem were short-sighted, focusing on cost minimization. Undoubtedly, the whole concept of recycling was founded on the pillars of sustainability. Accordingly, reverse logistics network design must be motivated by long-term environmental and societal benefits. This fact has become even more prominent in the current pandemic environment as COVID-19 has added serious uncertainties and risks to the supply chain processes. This paper reiterates the essence of sustainability goals and proposes a multi-objective fuzzy mathematical model to RLND problem for ELVs under such a fragile and fuzzy environment. The coverage of the proposed model is to optimally determine the locations and numbers of the facilities and the flows among them concerning environmental, social, and economic aspects. Hence, the model aims to reach a robust compromise solution that leads to a resilient network design. A real case study on the ELV market in Istanbul/Turkey proves the merit of the developed model.
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    Energy-related CO2 emission forecast for Turkey and Europe and Eurasia A discrete grey model approach
    (Emerald Group Publishing Ltd, 2017) Ayvaz, Berk; Kusakci, Ali Osman; Temur, Gul T.
    Purpose - The global warming, caused by the anthropogenic greenhouse gases, has been one of the major worldwide issues over the last decades. Among them, carbon dioxide (CO2) is the most important one and is responsible for more than the two-third of the greenhouse effect. Currently, greenhouse gas emissions and CO2 emissions - the root cause of the global warming - in particular are being examined closely in the fields of science and they also have been put on the agenda of the political leaders. The purpose of this paper is to predict the energy-related CO2 emissions through using different discrete grey models (DGMs) in Turkey and total Europe and Eurasia region. Design/methodology/approach - The proposed DGMs will be applied to predict CO2 emissions in Turkey and total Europe and Eurasia region from 2015 to 2030 using data set between 1965 and 2014. In the first stage of the study, DGMs without rolling mechanism (RM) will be used. In the second stage, DGMs with RM are constructed where the length of the rolling horizons of the respected models is optimised. Findings - In the first stage, estimated values show that non-homogeneous DGM is the best method to predict Turkey's energy-related CO2 emissions whereas DGM is the best method to predict the energy-related CO2 emissions for total Europe and Eurasia region. According to the results in the second stage, NDGM with RM (k = 26) is the best method for Turkey while optimised DGM with RM (k = 4) delivers most reliable estimates for total Europe and Eurasia region. Originality/value - This study illustrates the effect of different DGM approaches on the estimation performance for the Turkish energy-related CO2 emission data.