Ümit Hacıoğlu

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.

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Ümit Hacıoğlu

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Business & Economics, Computer Science, Government & Law, Engineering, Public Administration

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Listeleniyor 1 - 10 / 26

Golden cut-oriented q-rung orthopair fuzzy decision-making approach to evaluation of renewable energy alternatives for microgeneration system investments
(Hindawi, 2022) Dinçer, Hasan; Aksoy, Tamer; Yüksel, Serhat; Hacıoğlu, Ümit; Hacıoğlu, Ümit; Aksoy, Tamer; Yönetim Bilimleri Fakültesi, İşletme Bölümü
This 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.
A critical approach to fatigue risk factors in cockpit and cabin crew for the flight safety in aviation industry
(Busssecon International, 2021) Özel, Engin; Hacıoğlu, Ümit; Hacıoğlu, Ümit; Yönetim Bilimleri Fakültesi, İşletme Bölümü
This paper aims to develop a critical approach to flight safety by assessing theoretical and empirical studies on fatigue risk factors in cockpit and cabin crew. This paper also builds a fundamental basis for managing fatigue risk factors in aviation industry. The maincontribution of the paper demonstrates the fact that primary and secondary fatigue risk factors in cockpit and cabin crew affect the level of job satisfaction, operational efficiency and flight security.
Analysis of solar module alternatives for efficiency-based energy investments with hybrid 2-tuple IVIF modeling
(Elsevier, 2023) Dinçer, Hasan; Yüksel, Serhat; Aksoy, Tamer; Hacıoğlu, Ümit; Mikhaylov, Alexey; Pinter, Gabor; Hacıoğlu, Ümit; Aksoy, Tamer; Yönetim Bilimleri Fakültesi, İşletme Bölümü
The purpose of this study is to examine optimal solar module investments. Firstly, key determinants of the performance of solar energy investments are evaluated by DEMATEL method with the 2-tuple IVIF sets. Moreover, the cell material alternatives for solar module investments are also ranked. For this purpose, an evaluation has been made by 2-tuple IVIF TOPSIS. The contributions of the paper are performing a priority analysis to understand the most significant factors to increase solar energy projects and creating an original model by the integration of DEMATEL and TOPSIS with the 2- tuple IVIF sets. The findings denote that crystalline silicon is the optimal solar panel module to increase the performance of these projects. In the short term, government subsidies can provide cost advantages to solar energy investors. It is not a very continuous practice to try to increase these projects only with government supports. The costs of solar energy projects should be reduced to solve this problem permanently. Owing to new technological developments, high cost problem of solar energy investments can be handled more successfully.
Application of M-SWARA and TOPSIS methods in the evaluation of investment alternatives of microgeneration energy technologies
(MDPI AG, 2022) Dinçer, Hasan; Yüksel, Serhat; Aksoy, Tamer; Hacıoğlu, Ümit; Hacıoğlu, Ümit; Aksoy, Tamer; Yönetim Bilimleri Fakültesi, İşletme Bölümü
Investments 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.
The evaluation of operational efficiencies of Turkish airports: An integrated spherical fuzzy AHP/DEA approach
(Elsevier, 2022) Yılmaz, Mustafa Kemal; Kuşakcı, Ali Osman; Aksoy, Mine; Hacıoğlu, Ümit; Hacıoğlu, Ümit; Yılmaz, Mustafa Kemal; Kuşakcı, Ali Osman; Yönetim Bilimleri Fakültesi, İşletme Bölümü
The demand for air transport services has significantly increased around the globe, which has brought new investments in airports, which, in turn, requires in-depth efficiency analysis of these capital-intensive endeavors. This study examines the operational efficiencies of 46 Turkish civil airports from 2015 to 2018. We employ a novel hybrid methodology that combines Spherical Fuzzy Sets based Analytic Hierarchy Process (SFS-AHP) and Data Envelopment Analysis (DEA), which provides a solid basis for efficiency analysis. To this end, it can handle the hesitancy and uncertainty that the subjective evaluation process of input and output factors possess. Then, we use Self Organizing Maps (SOM), a machine learning method for clustering, to examine the effect of outlier airports on the efficiency scores. Finally, a posthoc analysis is conducted with Tobit regression model to assess the explanatory power of external factors on the efficiency scores, i.e., tourism potential, number of international flights, distance to the city center, population, public/private ownership, and age of airport. The findings show that 67.2% of the Turkish airports operate below the optimal efficiency level, and 93.5% of them should make considerable efforts to refine their operations by implementing managerial and structural changes to reduce input factors. The results also suggest that the airports located in high-density touristic areas achieve higher efficiency levels. Those relatively closer to the city center lead to more airport traffic, generating more revenues. Thus, both factors have a significant impact on efficiency scores. The study provides a novel efficiency analysis framework for airport operators and policy makers that helps them make informed decisions.
Investigating the impact of Covid-19pandemicon stock markets: Evidence from global equity indices
(SSBFNET, 2021) Faque, Mustapher; Hacıoğlu, Ümit; Hacıoğlu, Ümit; Yönetim Bilimleri Fakültesi, İşletme Bölümü
This paper aims to examine the impact of Covid-19 pandemic on stock markets. This paper also analyses the stock market cointegration of selected global equity indices that performed better and have a quick speed of recovery during the pandemic. This paper also questions how increasing uncertainty and volatility deters investors’ perception of the diversification of equity investments. The dataset for the selected 12 global equity indices has been used from Thompson Reuters’s EIKON database in a given period of time between 2010 and 2021. This paper employs Vector Error Correction Models to assess the relationship among the selected global equity indices. Findings demonstrate that (i) there is an adverse impact of Covid-19 on the Global Equity markets, (ii) there is a clear sign of cointegration in global equity indices, (ii) investors can benefit from investing in particular equity indices that have exhibited quick speed of recovery from the pandemic records lows. The findings finally provide a strong foundation for constructing a resilient equity portfolio in a highly uncertain market environment.
Examining the relationship between burnout and job satisfaction of flight crew: An analysis on the critical fatigue risk factors in the aviation industry
(Busssecon International, 2021) Özel, Engin; Hacıoğlu, Ümit; Hacıoğlu, Ümit; Yönetim Bilimleri Fakültesi, İşletme Bölümü
Fatigue as an emerging flight safety issue in the aviation industry requires an elaborate understanding and critical approach for proactive aviation management practices. The level of flight crew stress and fatigue must be critically managed to prevent flight accidents. Additionally, stress and fatigue have a negative influence on job satisfaction levels. This paper aims to examine the critical fatigue risk factors that affect the performance and safety of airline pilots and crew in the aviation industry. This paper also analyses the relationship between burnout and job satisfaction sub-dimensions. A factor analysis with a target population of 254 international flight crew has been conducted using the Minnesota Job Satisfaction Survey and Maslach Burnout questionnaire. The main findings of the study demonstrate that (i) cockpit and cabin crews’ job satisfaction and performance have been affected by stress and fatigue, (ii) psychological depression, anxiety and personal problems of the flight crew are the main causes of emotional fatigue, (iii) extensive flight hours and dealing with problematic passengers increase flight crew fatigue, (iv) personal achievements concerns and depersonalization increase flight crew fatigue.
Complex fuzzy assessment of green flight activity investments for sustainable aviation
(IEEE, 2022) Aksoy, Tamer; Yüksel, Serhat; Dinçer, Hasan; Hacıoğlu, Ümit; Maialeh, Robin; Hacıoğlu, Ümit; Aksoy, Tamer; Yönetim Bilimleri Fakültesi, İşletme Bölümü
The 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.
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 Bölümü
Companies 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…
Analysis of environmental priorities for green project investments using an integrated q-rung orthopair fuzzy modeling
(IEEE, 2022) Dinçer, Hasan; Yüksel, Serhat; Mikhaylov, Alexey; Evgenievich Barykin, Sergey; Aksoy, Tamer; Hacıoğlu, Ümit; Hacıoğlu, Ümit; Aksoy, Tamer; Yönetim Bilimleri Fakültesi, İşletme Bölümü
Green 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.

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