Aksoy, Tamer
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Araştırma projeleri
Organizasyon Birimleri
Yönetim Bilimleri Fakültesi, İşletme Bölümü
Küresel rekabete ayak uydurmak ve sürdürülebilir olmak isteyen tüm şirketler ve kurumlar, değişimi doğru bir şekilde yönetmek, teknolojinin gerekli kıldığı zihinsel ve operasyonel dönüşümü kurumlarına hızlı bir şekilde adapte etmek zorundadırlar.
Adı Soyadı
Tamer Aksoy
İlgi Alanları
Finansal Muhasebe, Yönetim Muhasebesi, Stratejik Denetim/İç Denetim, İç Kontrol, Finans/Sürdürülebilirlik
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Aktif Personel
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Yayın Application of M-SWARA and TOPSIS methods in the evaluation of investment alternatives of microgeneration energy technologies(MDPI AG, 2022) Hacıoğlu, Ümit; Aksoy, Tamer; Hacıoğlu, Ümit; Aksoy, Tamer; Dinçer, Hasan; Yüksel, Serhat; Aksoy, Tamer; Hacıoğlu, Ümit; Yönetim Bilimleri Fakültesi, İşletme Bölümü; Yönetim Bilimleri Fakültesi, İşletme BölümüInvestments in microgeneration technologies help to boost the usage of clean energy while reducing pollution. However, selecting the appropriate investment remains the most critical phase in developing these technologies. This study aims to design a multi-criteria decision-making method (MCDM) to evaluate investment alternatives for microgeneration energy technologies. The proposed MCDM is based on a Multi Stepwise Weight Assessment Ratio Analysis (M-SWARA), to define the relative importance of the factors. The Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) and q-Rung Orthopair Fuzzy Soft Sets (q-ROFSs) are used to rank investment alternatives. Calculations were also made with Intuitionistic Fuzzy Sets (IFSs) and Pythagorean Fuzzy Sets (PFSs). For analysis, five evaluation criteria were selected based on the literature: frequency of maintenance, ease of installation, environmental adaptation, transmission technologies, and efficiency of cost. Similarly, six alternatives for microgeneration technology investments were selected: ground source heat pumps, micro hydroelectric power, micro combined heat and power, micro bioelectrochemical fuel cell systems, small-scale wind turbines, and photovoltaic systems. The results showed that cost efficiency was the most significant factor in the effectiveness of microgeneration energy investments, and the photovoltaic system was the best alternative to increase microgeneration energy technology investment performance. Furthermore, the results were the same for the analyses made with IFSs and PFSs, demonstrating the reliability of the proposed method. Therefore, investors in microgeneration technologies should prioritize photovoltaic systems. This conclusion is supported by the fact that photovoltaic is a renewable energy source that has witnessed the most technological improvements and cost reductions over the last decade.Yayın Analysis of environmental priorities for green project investments using an integrated q-rung orthopair fuzzy modeling(IEEE, 2022) Hacıoğlu, Ümit; Aksoy, Tamer; Hacıoğlu, Ümit; Aksoy, Tamer; Dinçer, Hasan; Yüksel, Serhat; Mikhaylov, Alexey; Evgenievich Barykin, Sergey; Aksoy, Tamer; Hacıoğlu, Ümit; Yönetim Bilimleri Fakültesi, İşletme Bölümü; Yönetim Bilimleri Fakültesi, İşletme BölümüGreen energy projects contribute to sustainable economic development of countries with the employment of environmentally friendly energy production strategies. However, environmental priorities should be examined for this situation. Therefore, priority analysis should be executed for the environmental issues while implementing green investment projects. Accordingly, this study aims at proposing a unique decision-making model based on orthopair fuzzy sets and the golden cut degrees for the environmental priorities of green project investments. The main novelty of the study stems from its proposed integrated model by equipping the Multi-SWARA, and TOPSIS based on the q-ROFSs technique with the golden cut. A set of criteria is identified for measuring the green projects’ environmental priorities while several project alternatives are also determined with the supporting literature. Appropriately, the extensions of Multi-SWARA and TOPSIS methods have been applied for weighting and ranking the factors, respectively, in the integrated approach. Additionally, a comparative evaluation is performed with the help of VIKOR method to rank the alternatives. Besides, the sensitivity analysis is applied to illustrate the coherency of the weighting results in the decision-making approach. Accordingly, 5 cases are considered to measure the effects of changing weight results. It is defined that this model is coherent and could be extended for further studies. It is concluded that the reduction of emissions is the most essential item for the environmental priorities of green project investments. Pollution control, waste management and eco-friendly transportation activities are the most critical alternatives. Therefore, this study recommends that investors of green projects should prioritize the strategies of minimizing carbon emissions problem. In this context, investing in renewable energy technologies will help green project investors solve this problem.Yayın Q-ROF fuzzy TOPSIS and VIKOR methods for the selection of sustainable private health insurance policies(MDPI, 2023) Hacıoğlu, Ümit; Aksoy, Tamer; Hacıoğlu, Ümit; Aksoy, Tamer; Erdebilli, Babek; Gecer, Ebru; Yılmaz, İbrahim; Aksoy, Tamer; Hacıoğlu, Ümit; Dinçer, Hasan; Yüksel, Serhat; Yönetim Bilimleri Fakültesi, İşletme Bölümü; Yönetim Bilimleri Fakültesi, İşletme BölümüAs a result of the inability of people to meet their demands in the face of increasing demands, people tend to have private health insurance in addition to the general health insurance offered as a public service. Due to the increasing trend of taking out private sustainable health insurance, the number of private sustainable health insurance plans in the health insurance market has increased significantly. Therefore, people may be confronted by a wide range of private health insurance plan options. However, there is limited information about how people analyze private health insurance policies to protect their health in terms of benefit payouts as a result of illness or accident. Thus, the objective of this study is to provide a model to aid people in evaluating various plans and selecting the most appropriate one to provide the best healthcare environment. In this study, a hybrid fuzzy Multiple Criteria Decision Making (MCDM) method is suggested for the selection of health insurance plans. Because of the variety of insurance firms and the uncertainties associated with the various coverages they provide, q-level fuzzy set-based decision-making techniques have been chosen. In this study, the problem of choosing private health insurance was handled by considering a case study of evaluations of five alternative insurance companies made by expert decision makers in line with the determined criteria. After assessments by expert decision makers, policy choices were compared using the Q-Rung Orthopair Fuzzy (Q-ROF) sets Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) and Q-ROF VIšeKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) methods. This is one of the first attempts to solve private health policy selection under imprecise information by applying Q-ROF TOPSIS and Q-ROF VIKOR methods. At the end of the case study, the experimental results are evaluated by sensitivity analysis to determine the robustness and reliability of the obtained results.Yayın Assessing the electricity production capacities of emerging markets for the sustainable investments(IEEE, 2023) Aksoy, Tamer; Yüksel, Serhat; Dinçer, Hasan; Hacıoğlu, Ümit; Mikhaylov, Alexey; Muyeen, S. M.; Hacıoğlu, Ümit; Aksoy, Tamer; Yönetim Bilimleri Fakültesi, İşletme BölümüIt is essential to supply the necessary electricity for both the increase in the quality of life of the citizens and the stable growth of the country’s economy. For countries to have energy independence, they need to increase their electricity generation capacity. However, all alternatives required to increase electrical capacity have both advantages and disadvantages. Within this scope, it is not easy for countries to make the right investment decisions. Therefore, a comprehensive analysis is needed to determine the right investment policy. The purpose of this study is to evaluate the electricity production capacities of emerging markets. A new fuzzy decision-making model has been constructed to find a solution for this situation. The groups for the electricity production capacities are examined by the extension of DEMATEL with Quantum Spherical fuzzy sets and golden ratio. In the following stage, emerging seven economies are ranked by using QSF TOPSIS technique. This situation helps to understand which of these countries are more successful in generating electricity capacity effectively. The main novelty is to define the most significant electricity generation alternatives by a novel model that integrates DEMATEL and TOPSIS with QSFSs and golden ratio. The results demonstrate that solar photovoltaic is the most optimal way to increase electricity capacity of the countries. Additionally, China is the most successful emerging country to generate electricity in an efficient way. Countries should take some actions to increase their solar energy investments. First, it would be appropriate to provide tax exemptions to solar energy investors so that the costs of these projects can be decreased. Additionally, investments in solar energy technologies need to be further increased.Yayın Golden cut-oriented q-rung orthopair fuzzy decision-making approach to evaluation of renewable energy alternatives for microgeneration system investments(Hindawi, 2022) Hacıoğlu, Ümit; Aksoy, Tamer; Hacıoğlu, Ümit; Aksoy, Tamer; Dinçer, Hasan; Aksoy, Tamer; Yüksel, Serhat; Hacıoğlu, Ümit; Yönetim Bilimleri Fakültesi, İşletme Bölümü; Yönetim Bilimleri Fakültesi, İşletme BölümüThis study aims to find an appropriate system for microgeneration energy investments and identify optimal renewable energy alternatives for the effectiveness of these projects. In this context, a model is constructed by multi stepwise weight assessment ratio analysis (M-SWARA) and technique for order preference by similarity to ideal solution (TOPSIS) with q-rung orthopair fuzzy sets (q-ROFSs) and golden cut. At the first stage, five different systems are weighted for the effectiveness of the microgeneration energy investments. Secondly, four different renewable energy alternatives are ranked regarding the performance of these projects. In addition, a comparative analysis is also implemented with intuitionistic fuzzy sets (IFSs) and Pythagorean fuzzy sets (PFSs). The findings are the same in all different fuzzy sets that demonstrates the reliability of the findings. It is determined that grid-connected with battery backup is the most important system choice. On the other hand, solar energy is the most appropriate alternative for microgeneration system investments. Grid-connected system should be implemented for the performance of the microgeneration projects. Hence, providing a sustainable access to the electricity can be possible. Sufficient amount of electricity may not be obtained from wind and solar energy because of the climate changes. In this process, grid-connected system can handle this problem effectively.Yayın Analysis of environmental impact for material production investments using a novel soft computing methodology(IEEE, 2023) Hacıoğlu, Ümit; Aksoy, Tamer; Hacıoğlu, Ümit; Aksoy, Tamer; Dinçer, Hasan; Eti, Serkan; Aksoy, Tamer; Yüksel, Serhat; Hacıoğlu, Ümit; Mikhaylov, Alexey; Muyeen, S. M.; Yönetim Bilimleri Fakültesi, İşletme Bölümü; Yönetim Bilimleri Fakültesi, İşletme BölümüThe purpose of this study is to evaluate the environmental impacts of material production investments. The factors of Higg Materials Sustainability Index are defined as the parameters. These factors are weighted by considering T-SF TOPSIS-DEMATEL. Moreover, the items of the life cycle process are defined as alternative set for measuring the environmental effects of each process in the sustainable production investments. These alternatives are ranked with interval valued SF MAIRCA. The calculations are also made for different t, u and d values with the aim of making comparative evaluations. The main contribution of this study is that a priority analysis has been made so that the most significant indicators are defined for the companies to increase sustainability in material production investment process. Another important novelty of this paper is that a new model is created by the name of TOPSIS-DEMATEL. This situation has a positive influence on both increasing methodological originality and overcoming criticized issues of DEMATEL. The results are quite similar for all conditions, so it is understood that the proposed model provides consistent and coherent findings. It is concluded that chemistry is the most critical factor for environmental impact for material production investments. Moreover, recycle is determined as the most optimal alternative.Yayın Complex fuzzy assessment of green flight activity investments for sustainable aviation(IEEE, 2022) Hacıoğlu, Ümit; Aksoy, Tamer; Hacıoğlu, Ümit; Aksoy, Tamer; Aksoy, Tamer; Yüksel, Serhat; Dinçer, Hasan; Hacıoğlu, Ümit; Maialeh, Robin; Yönetim Bilimleri Fakültesi, İşletme Bölümü; Yönetim Bilimleri Fakültesi, İşletme BölümüThe aviation industry harms the environment mainly via the creation of carbon emissions. Hence, action needs to be taken to ensure the environmental sustainability of the aviation industry such as the recycling of waste products, effective waste management and the introduction of energy efficiency measures. However, at the same time, the implementation of improvements to remediate such problems leads to the creation of additional costs for aviation companies. Companies thus need to conduct comprehensive priority analyses regarding the optimum strategy for the sustainability of the aviation industry. However, there is a very limited number of studies in the literature that focused on which approach should be prioritized. Accordingly, this study aimed at the assessment of the viability of investing in so-called green flight measures in the aviation industry, for which a completely original decision-making model was created. Firstly, the various strategic priorities were weighted and the impact-relation directions between them illustrated aimed at the identification of potential influences by means of a multi stepwise weight assessment ratio analysis (M-SWARA) methodology that incorporates bipolar q-rung orthopair fuzzy sets (q-ROFSs) and golden cut. Secondly, the various flight activities are ranked, and the potential impacts of these activities determined in terms of the strategic priorities of a sustainable aviation industry employing q-ROF as the elimination and choice translating reality (ELECTRE) technique. All the calculations were also computed with intuitionistic fuzzy sets (IFSs) and Pythagorean fuzzy sets (PFSs) aimed at verifying the validity of the findings. The analysis concluded that while energy efficiency comprises the most important factor in terms of strategic priority investment for the circular economy-based aviation industry, emergency response makes up the most crucial activity in the industry. Operational efficiency must be prioritized to decrease the amount of fuel consumed, in connection with which flight routes should be planned according to current weather conditions, which would serve to shorten flight times and, thus, help to increase energy efficiency. Such an approach would make a positive contribution to minimizing carbon emissions aimed at ensuring the sustainability of the aviation industry.Yayın An interval-valued pythagorean fuzzy AHP and COPRAS hybrid methods for the supplier selection problem(Springer Science and Business Media B.V., 2023) Erdebilli, Babek; Yılmaz, İbrahim; Aksoy, Tamer; Hacıoğlu, Ümit; Yüksel, Serhat; Dinçer, Hasan; Hacıoğlu, Ümit; Aksoy, Tamer; Yönetim Bilimleri Fakültesi, İşletme BölümüCompanies must be able to identify their suppliers appropriately and effectively in order to survive in the competitive market conditions. In order to fulfill and surpass the expectations of the consumers and clients, companies need to interact with the relevant suppliers. It is a tough manner for companies to select the best supplier from a large number of relevant alternatives. The selection process of the appropriate supplier involves multiple interacting and competing factors. Generally, the selection process and its results cause a waste of time and money. For this purpose, MCDM methodologies are utilized to manage this complex process efficiently. MCDMs allows for consistent and accurate decision-making as well as the selection of the most appropriate supplier. MCDM is one the most preferred tool to select the best alternative under the conflicting and competitive criteria when the evaluations are made in crisp numbers. Therefore, MCDM methods are preferred in various applications in academia and real life. However, the evaluations could not be always possible with crisp numbers, especially in vague environments or evaluations needs qualitative data…