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Article Citation - WoS: 89Citation - Scopus: 99Optimization of Electric Vehicle Recharge Schedule and Routing Problem With Time Windows and Partial Recharge: a Comparative Study for an Urban Logistics Fleet(Elsevier, 2021) Bac, Ugur; Baç, Uğur; Erdem, Mehmet; Erdem, Mehmet; Baç, Uğur; Erdem, Mehmet; Industrial Engineering; Industrial EngineeringThe use of electric vehicles (EVs) is becoming more and more widespread and the interest in these vehicles is increasing each day. EVs promise to emit less air pollution and greenhouse gas (GHG) emissions with lower operational costs when compared to fossil fuel-powered vehicles. However, many factors such as the limited mileage of these vehicles, long recharging times, and the sparseness of available recharging stations adversely affect the preferability of EVs in industrial and commercial logistics. Effective planning of EV routes and recharge schedules is vital for the future of the logistics sector. This paper proposes an electric vehicle routing problem with the time windows (EVRPTW) framework, which is an extension of the well-known vehicle routing problem (VRP). In the proposed model, partial recharging is considered for the EVRPTW with the multiple depots and heterogeneous EV fleet and multiple visits to customers. While routing a set of heterogeneous EVs, their limited ranges, interdependent on the battery capacity, should be taken into consideration and all the customers' deliveries should be completed within the predetermined time windows. To deal with this problem, a series of neighbourhood operators are developed for the local search process in the variable neighbourhood search (VNS) and variable neighbourhood descent (VND) heuristics. The proposed solution algorithms are tested in large-scale instances. Results indicate that the proposed heuristics perform well as to this problem in terms of optimizing recharging times, idle waiting times, overtime of operators, compliance with time windows, number of vehicles, depots, and charging stations used.Article Citation - WoS: 48Citation - Scopus: 52A Comprehensive Evaluation of the Most Suitable Hvac System for an Industrial Building by Using a Hybrid Building Energy Simulation and Multi Criteria Decision Making Framework(Elsevier, 2021) Bac, Ugur; Alaloosi, Khalid Abdulwahab Mohamed Saed; Turhan, CihanGreat demand for energy and growing trend in the use of energy-efficient HVAC systems force researchers to focus on the importance of choosing the most appropriate HVAC system for industrial buildings during design process. Therefore, developing a model to select the most suitable HVAC system is vital for industrial buildings. To this aim, this study provides a comprehensive evaluation of different HVAC systems for an industrial building by using hybrid multi criteria decision making (MCDM) method. An industrial building in Ankara/Turkey is selected as a case building. Eleven HVAC systems are evaluated based on twenty seven criteria, which are determined as a result of extensive literature research, and are grouped under six categories including ergonomic, environmental, reliability, technical, and economical aspects. A hybrid application of building energy simulation (BES) integrated modified Stepwise Weight Assessment Ratio Analysis (SWARA) and Weighted Additive Sum Product Assessment (WASPAS) framework is developed for supporting the decision making process. The novelty of the study is integrating the objective results of a well-calibrated dynamic BES tool with subjective criteria which are collected from expert opinions by applying questionnaires with face-to-face interview method. The results of MCDM framework and sensitivity analysis showed that the water-source heat pump is the best and suitable alternative for the industrial building. The outcome of this study would benefit the HVAC engineers and specialists in order to design the best HVAC systems in industrial buildings while providing an insight into different criteria. Moreover, key contribution to the literature is the usage of hybrid MCDM framework integrated with BES tool in the building sector.Article Citation - WoS: 4Citation - Scopus: 6Strategic Electricity Production Planning of Turkey Via Mixed Integer Programming Based on Time Series Forecasting(Mdpi, 2023) Yoruk, Gokay; Bac, Ugur; Yerlikaya-Ozkurt, Fatma; Unlu, Kamil DemirberkThis study examines Turkey's energy planning in terms of strategic planning, energy policy, electricity production planning, technology selection, and environmental policies. A mixed integer optimization model is proposed for strategic electricity planning in Turkey. A set of energy resources is considered simultaneously in this research, and in addition to cost minimization, different strategic level policies, such as CO2 emission reduction policies, energy resource import/export restriction policies, and renewable energy promotion policies, are also considered. To forecast electricity demand over the planning horizon, a variety of forecasting techniques, including regression methods, exponential smoothing, Winter's method, and Autoregressive Integrated Moving Average methods, are used, and the best method is chosen using various error measures. The optimization model constructed for Turkey's Strategic Electricity Planning is obtained for two different planning intervals. The findings indicate that the use of renewable energy generation options, such as solar, wind, and hydroelectric alternatives, will increase significantly, while the use of fossil fuels in energy generation will decrease sharply. The findings of this study suggest a gradual increase in investments in renewable energy-based electricity production strategies are required to eventually replace fossil fuel alternatives. This change not only reduces investment, operation, and maintenance costs, but also reduces emissions in the long term.Article Citation - WoS: 26Citation - Scopus: 23An Integrated Swara-Waspas Group Decision Making Framework To Evaluate Smart Card Systems for Public Transportation(Mdpi, 2020) Bac, UgurRecent technological developments affect daily life as much as they affect the industries. As part of these developments, automation and smart systems are important part of everyday life. Smart card systems are one of the well-known types of smart automation technology being used by the majority of the population in public transportation in most developed countries. Even though automated fare payment systems have been widely integrated into public transportation in developed countries, integration of smart card systems is still under consideration in most developing countries. The aim of this study is to propose a framework to evaluate different smart card systems to determine the best one and additionally validate their benefits when compared with the traditional fare payment system. For this purpose, an integrated multi-criteria decision making (MCDM) framework is used that combines two recent and popular methodologies together. The proposed methodology employs Stepwise Weight Assessment Ratio Analysis (SWARA) method for determination of criteria weights in the decision model and the Weighted Additive Sum Product Assessment (WASPAS) method for comparison of alternatives. Research results revealed that all smart card systems show improvements under performance, reliability, and user satisfaction related criteria. However, traditional fare payment systems are found to be safer under consideration of personal data protection. Findings of this study can be used to select the best smart card system and as a guide for deciding on areas of improvement during the implementation phase to ensure higher user satisfaction.
