Browsing by Author "Ayag, Zeki"

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Citation Count: 1
Achieving Sustainability in Solar Energy Firms in Turkey through Adopting Lean Principles
(Mdpi, 2022) Ayağ, Zeki; Ayag, Zeki
Lean principles and sustainability are considered important terms in business. Solar firms are witnessing great competition to fulfill energy requirements, suffering from a huge amount of waste, negatively affecting the sustainability dimensions. Thus, the aim of the study is to build a framework for solar energy firms to achieve sustainability through adopting lean principles, which will help to fix many problems as waste and costs. The method included reviewing the literature to explore the founding of the relation between the two terms, and using a questionnaire that was directed to the responsible people in Turkish solar energy firms. The results of the survey were analyzed to: (1) Find out what the responsible people think about the two terms lean and sustainability; (2) Measure the probable relationship between lean principles and sustainability dimensions by applying a linear regression test; (3) Use the results of point number two to build the framework. The result showed there was a high level of relative importance about the two terms from the point of view of managers and experts in solar firms. In addition, the study found a relationship between adopting pull and flow principles of lean, and achieving economic and social dimensions of sustainability, this finding is represented in a framework.
Citation Count: 17
Concept selection with hesitant fuzzy ANP-PROMETHEE II
(Taylor & Francis Ltd, 2021) Samanlıoğlu, Funda; Ayağ, Zeki
An integrated approach is given for the assessment and ranking of concepts as part of the new product development (NPD) process. Selection of the best concept in NPD involves multiple criteria decision-making (MCDM) since there are numerous possibly competing criteria to consider. Here, hesitant fuzzy Analytic Network Process (H-F-ANP) and hesitant fuzzy Preference Ranking Organization Method for Enriching Evaluations II (H-F-PROMETHEE II) are integrated to assess the concepts and determine the best. In the hesitant fuzzy ANP-PROMETHEE II (H-F-ANP-PROMETHEE II), H-F-ANP is applied to calculate criteria weights, taking into consideration inner and outer dependence and feedback interactions between criteria and H-F-PROMETHEE II is implemented to rank concept alternatives, employing the calculated criteria weights. A demonstrative example is given where five concepts are evaluated by three decision makers (DMs) to exhibit the applicability. For comparison, H-F-ANP-VIKOR is utilized.
Citation Count: 0
Evaluation of Gas-Fired Combi Boilers with HF-AHP-MULTIMOORA
(Hindawi Ltd, 2022) Samanlıoğlu, Funda; Ayağ, Zeki; Kirkil, Goekhan; Yucal, Esra
There are many alternative gas-fired combi boilers that can be used to heat residential homes. Evaluation and selection of gas-fired combi boilers for buildings is an intricate multi-criteria decision-making (MCDM) problem involving perhaps contradictory quantifiable and qualitative criteria. In this research, as the MCDM approach, hesitant fuzzy linguistic analytic hierarchy process (HF-AHP) and hesitant fuzzy linguistic multiple objective optimization based on ratio analysis plus full multiplicative form (MULTIMOORA) (HF-MULTIMOORA) are integrated to assess and rank combi boiler alternatives for buildings. First, with HF-AHP, fuzzy criteria weights are determined and then with HF-MULTIMOORA, boiler alternatives are ranked from best to worst. In this integrated HF-AHP-MULTIMOORA method, evaluations of decision-makers are combined with fuzzy envelope approach and then triangular fuzzy numbers are utilized. For comparison analysis, HF-AHP-TOPSIS method is also applied to the same problem. A case study in Turkey is presented where ten combi boiler alternatives are assessed based on fifteen criteria by five decision-makers. We have used various selection criteria for boilers ranging from maximum temperature, heating capacity up to environmental effects and decided on the best combi boiler for heating residential buildings in Turkey.
Citation Count: 0
A Hesitant Fuzzy Linguistic Terms Set-Based AHP and TOPSIS Methodology for Fuel Coal Type Selection Problem of Industrial Facilities
(Old City Publishing inc, 2024) Ayağ, Zeki; Ayag, Zeki
Coal is still used widely by both industrial facilities and coal fired power plants. Lignite, hard coal, coke, and imported coal are some alternatives. The coal has ash content, moisture content, heat rate, volatile matter, carbon content, sulphur content, and size that need to be considered as well as price. The suppliers provide coal products for each coal type, and the most appropriate coal product needs to be selected considering different parameters. Therefore, in this paper, a hesitant fuzzy linguistic term sets- based AHP (HFLTS-AHP) and TOPSIS method are used to select the best coal type alternative for industrial facilities. As the HFLTS-AHP is used to weight the evaluation criteria, TOPSIS is utilized to rank the fuel coal type alternatives. The proposed methodology offers an innovative and novel approach to help industrial facilities select the appropriate coal product while balancing the outputs, such as carbon, sulphur, ash content, and so on. In another point of view, the motivation of this research is to help industrial firms find out the ultimate fuel coal alternative based on their needs. This objective is realized using the proposed approach that integrates the HFLTS-AHP and TOPSIS approaches for the related problem, also utilizing group decision making. Moreover, this approach is concreted by an Excel template that provides an effective tool for firms to realize the evaluation process without many tiresome fuzzy comparisons and complex calculations. Furthermore, in the paper, a real-life case study in Turkish industrial facilities is presented to demonstrate the effectiveness and applicability of the proposed approach to readers and practitio ners. In this case, seven coal type options are evaluated in terms of eight criteria by three decision makers, and the best coal type alternative is determined.
Citation Count: 0
An Intelligent Approach to Evaluating CAD Software Packages Through Hesitant Fuzzy AHP
(World Scientific Publ Co Pte Ltd, 2022) Ayağ, Zeki
The evaluation of computer-aided design (CAD) packages among the rising number of alternatives in the market has been a critical process for companies because it directly affects the performance of their design/engineering-related activities in a new product development (NPD) as well as in R&D departments. Moreover, it is seen as an important step towards the computer-integrated manufacturing (CIM) environment. On the other hand, the evaluation process of CAD software packages is a multiple-criteria decision-making (MCDM) problem in the presence of sets of alternatives and evaluation criteria, which should be solved using one of the MCDM methods in the current literature. Therefore, in this study, the analytic hierarchy process (AHP), successfully implemented in both academic research and practices, is used for CAD software selection problem. The method is also used with the group decision-making approach to reach a more reliable solution. Additionally, due to the fact that the crisp pairwise comparison in the traditional AHP method seems to be insufficient and imprecise to capture the right judgments of decision makers (DMs), the hesitant fuzzy linguistic term-sets are integrated with the AHP approach (the hesitant F-AHP) to model the vagueness and uncertainty on judgments of the DMs. This proposed approach is also supported with a user-friendly Excel template that provides an effective tool for companies to evaluate and rank CAD software packages without many tiresome fuzzy comparisons and complex calculations. Moreover, in the paper, a numerical example is presented to demonstrate the effectiveness and applicability of the proposed approach to potential readers and practitioners. In this example, five CAD software options are evaluated based on six criteria by three DMs; and the best alternative is determined.