Ayağ, Zeki
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Ayağ, Zeki
Z.,Ayağ
Z. Ayağ
Zeki, Ayağ
Ayag, Zeki
Z.,Ayag
Z. Ayag
Zeki, Ayag
Ayağ,Z.
Zeki Ayağ
Z.,Ayağ
Z. Ayağ
Zeki, Ayağ
Ayag, Zeki
Z.,Ayag
Z. Ayag
Zeki, Ayag
Ayağ,Z.
Zeki Ayağ
Job Title
Prof. Dr.
Email Address
Main Affiliation
Industrial Engineering
Status
Former Staff
Website
ORCID ID
Scopus Author ID
Turkish CoHE Profile ID
Google Scholar ID
WoS Researcher ID
Sustainable Development Goals
11
SUSTAINABLE CITIES AND COMMUNITIES
0
Research Products
10
REDUCED INEQUALITIES
0
Research Products
9
INDUSTRY, INNOVATION AND INFRASTRUCTURE
8
Research Products
12
RESPONSIBLE CONSUMPTION AND PRODUCTION
0
Research Products
2
ZERO HUNGER
0
Research Products
3
GOOD HEALTH AND WELL-BEING
0
Research Products
13
CLIMATE ACTION
0
Research Products
7
AFFORDABLE AND CLEAN ENERGY
6
Research Products
5
GENDER EQUALITY
0
Research Products
6
CLEAN WATER AND SANITATION
0
Research Products
8
DECENT WORK AND ECONOMIC GROWTH
2
Research Products
16
PEACE, JUSTICE AND STRONG INSTITUTIONS
0
Research Products
4
QUALITY EDUCATION
0
Research Products
15
LIFE ON LAND
0
Research Products
1
NO POVERTY
0
Research Products
14
LIFE BELOW WATER
0
Research Products
17
PARTNERSHIPS FOR THE GOALS
0
Research Products
This researcher does not have a Scopus ID.
This researcher does not have a WoS ID.
Scholarly Output
45
Articles
31
Views / Downloads
403/0
Supervised MSc Theses
5
Supervised PhD Theses
1
WoS Citation Count
1030
Scopus Citation Count
1488
WoS h-index
16
Scopus h-index
19
Patents
0
Projects
0
WoS Citations per Publication
22.89
Scopus Citations per Publication
33.07
Open Access Source
22
Supervised Theses
6
| Journal | Count |
|---|---|
| Journal of Intelligent Manufacturing | 5 |
| Journal of Intelligent & Fuzzy Systems | 5 |
| International Journal of Intelligent Computing and Cybernetics | 2 |
| International Journal of Energy Sector Management | 2 |
| International Journal of Production Research | 2 |
Current Page: 1 / 4
Scopus Quartile Distribution
Competency Cloud
45 results
Scholarly Output Search Results
Now showing 1 - 10 of 45
Master Thesis A Fuzzy Ahp Approach for Financial Performance Evaluation Airline Companies(Kadir Has Üniversitesi, 2012) Gürel, Sinem; Ayağ, ZekiPrevious researches focused on operation performance. This thesis purposes for evaluating the financial performance of the airlines. In order to achieve financial objectives to be incorporated into the financial performance of their degree. It is a method to measure the results of a company?s operations in a monetary term. The problem is modeled by multi-criteria decision making (MCDM) one. Multi criteria decision making (MCDM) is a method of the most important fields of operations research and deals with the problems that include multiple and conflicting objectives. It is obvious that when more than objective exists in the problem, making a decision becomes more complex. To solve the problem, I used the fuzzy numbers to explain their values. After that, I used a method of fuzzy multi criteria group decision making (FMCGDM) as Fuzzy Analytic Hierarchy Process (FAHP) to solve the problem of the evaluation of airlines? financial performances. At first time the decision making process of the financial performance is investigated, when financial ratios are given by a fuzzy function, they are obtained through classical methods. After that, we will discuss the main advantages of the new approach. Finally, we illustrate an experimantal model of evaluation of the three domestic airlines? financial performance in Turkey.Article Citation - Scopus: 2Cad Software Evaluation for Product Design To Exchange Data in a Supply Chain Network(ExcelingTech Publishers, 2015) Ayağ, ZekiThe sharing information in a supply chain environment especially CAD models and drawings are so important companies. So the selection of the most satisfying computer-aided design (CAD) software which enables to exchange data through supply chain network has been major issues for companies in a supply chain. The selection process of CAD software among the raising number of alternatives in the market has been very vital and critical issue for companies that aim to make their design and engineering related activities automated towards computer integrated manufacturing (CIM) environment. Therefore most companies have used various methods to successfully carry out this difficult and time-consuming process. Of these methods Analytic Hierarchy Process (AHP) has been widely used for Multiple Criteria Decision Making (MCDM) problems in both academic researches and practices. But in some cases due to the vagueness and uncertainty on judgments of the decisionmaker(s) the crisp pair wise comparison in the conventional AHP seems to be insufficient and imprecise to capture the right judgments of decision-maker(s). Therefore a fuzzy logic is introduced in the pair wise comparison of AHP to make up for this deficiency in the conventional AHP called as fuzzy AHP. In this paper a fuzzy AHP-based approach is proposed to evaluate a set of CAD software alternatives in the market to reach the best satisfying one based on the needs of company. © ExcelingTech Pub UK.Article Citation - Scopus: 3An Intelligent Approach To Evaluating Cad Software Packages Through Hesitant Fuzzy Ahp(World Scientific Publ Co Pte Ltd, 2022) Ayag, ZekiThe 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.Master Thesis Minimizing the Defect Rate Using Six Sigma Dmaic Method; a Case Study in Supsan A.ş.(Kadir Has Üniversitesi, 2016) Aslan, Nazmiye Yağmur; Ayağ, ZekiToday manufacturing industries are highly impacted by the fast changing economic conditions. In this scenario, manufacturing industries become face to face with global competition due to globalization. The major problems of these industries are declining profit margin, customer demand for high quality product and product variety. Therefore so many organizations, especially in manufacturing sector, understand the importance of quality. Companies try to implement various strategies and innovations for enhancing their producing process. A very powerful philosophy in this area is Six Sigma. The aim of Six Sigma is to reduce cost, waste and increase productivity to produce high-quality products. So this study is applied to improve the quality of the manufactured valves, reduce the manufacturing waste and increase the yield of the manufacturing process by applying the Six Sigma methodology. Also comparison analysis is made between approaches as DMAIC, Jidoka, Value Stream Tranformation, Kaizen. In result of the analysis DMAIC is chosen for this project. DMAIC approach is a business strategy help to improve business profitability and efficiency of operations to meet customer needs and expectations. In this search discusses the quality and productivity improvement in an manufacturing enterprise which is called SUPSAN. And this search deals with an application of Six Sigma DMAIC methodology in SUPSAN to improve quality performance, to identify root causes of failure in Stellite Coating Process which is found with help of DMAIC tools. Several tools are used to identify root causes and situation analysed with help of Pareto Charts, FMEA, SIPOC, C&E Diagram. In improve phase Process Capability Analysis and Implementation Plan are made. Also improvement solutions are applied. Then with the help of tools as Control Charts, SPC Analysis results tracked, documented and controlled.In SUPSAN, the appliation of Six Sigma DMAIC methodology resulted in a reduction in the defect rate from 4.34% to 2%.Article Citation - WoS: 19Citation - Scopus: 23A Comparison Study of Fuzzy-Based Multiple-Criteria Decision-Making Methods To Evaluating Green Concept Alternatives in a New Product Development Environment(EMERALD GROUP PUBLISHING LTD, 2021) Ayağ, ZekiPurpose In this paper, the four popular multiple-criteria decision-making (MCDM) methods in fuzzy environment are utilized to reflect the vagueness and uncertainty on the judgments of decision-makers (DMs), because the crisp pairwise comparison in these conventional MCDM methods seems to be insufficient and imprecise to capture the right judgments of DMs. Of these methods, as Fuzzy analytic hierarchy process (F-AHP) is used to calculate criteria weights, the other methods; Fuzzy Technique for Order of Preference by Similarity to Ideal Solution (F-TOPSIS), Fuzzy Grey relational analysis (F-GRA) and Fuzzy Preference Ranking Organization METhod for Enrichment of Evaluations (F- PROMETHEE II) are used to rank alternatives in the three different ways for a comparative study. Design/methodology/approach The demand for green products has dramatically increased because the importance and public awareness of the preservation of natural environment was taken into consideration much more in the last two decades. As a result of this, especially manufacturing companies have been forced to design more green products, resulting in a problem of how they incorporate environmental issues into their design and evaluate concept options. The need for the practical decision-making tools to address this problem is rapidly evolving since the problem turns into an MCDM problem in the presence of a set of green concept alternatives and criteria. Findings The incorporation of fuzzy set theory into these methods is discussed on a real-life case study, and a comparative analysis is done by using its numerical results in which the three fuzzy-based methods reveal the same outcomes (or rankings), while F-GRA requires less computational steps. Moreover, more detailed analyses on the numerical results of the case study are completed on the normalization methods, distance metrics, aggregation functions, defuzzification methods and other issues. Research limitations/implications The designing and manufacturing environmental-friendly products in a product design process has been a vital issue for many companies which take care of reflecting environmental issues into their product design and meeting standards of recent green guidelines. These companies have utilized these guidelines by following special procedures at the design phase. Along the design process consisting of various steps, the environmental issues have been considered an important factor in the end-of-life of products since it can reduce the impact on the nature. In the stage of developing a new product with the aim of environmental-friendly design, the green thinking should be incorporated as early as possible in the process. Practical implications The case study was inspired from the previous work of the author, which was realized in a hot runner systems manufacturer, used in injection molding systems in a Canada. In a new product development process, the back- and front-ends of development efforts mainly determine the following criteria: cost, risk, quality and green used in this paper. The case study showed that the three fuzzy MCDM methods come to the same ranking outcomes. F-GRA has a better time complexity compared to the other two methods and uses a smaller number of computational steps. Moreover, a comparative analysis of the three F-MCDM methods; F-PROMETHEE II, F-TOPSIS and F-GRA used in ranking for green concept alternatives using the numerical results of the case study. For the case study; as seen in table 20, the three F-MCDM methods produced the numerical results on the rankings of the green concept alternatives as follows; {Concept A-Concept C-Concept B-Concept D}. Social implications Inclusion of environmental-related criteria into concept selection problem has been gaining increasing importance in the last decade. Therefore, to facilitate necessary calculations in applying each method especially with its fuzzy extension, it can be developed a knowledge-based (KB) or an expert system (ES) to help the DMs make the required calculations of each method, and interpret its results with detailed analysis. Originality/value The objective of the research was to propose a F-AHP based F-MCDM approach to green concept selection problem through F-PROMETHEE II, F-TOPSIS and F-GRA methods. As the F-AHP is used to weight evaluation criteria, the other methods are respectively used for ranking the concept alternatives and determine the best concept alternative.Conference Object Ahp-Based Approach To Evaluate Solar Power Plant Location Alternatives(Intl Inst Social & Economic Sci, 2016) Ayağ, ZekiSolar energy is the most readily available source of energy, and one of the most important sources of the renewable energy, because it is non-polluting and helps in lessening the greenhouse effect. Main problem of establishing a solar power plant is to determine its location. In the presence of many location alternatives and evaluation criteria, a multiple-criteria decision making problem arises. In this work, the location problem will be solved by using analytic hierarchy process (AHP) to figure out the most satisfying alternative. A numerical example is also included to show the proposed methodology in Turkey. . . . .Article Citation - Scopus: 3An Intelligent Approach To Prioritize Logistics Requirements in Food Industry(ExcelingTech Publishers, 2014) Ayağ, ZekiThe aim of this study is to analyze dairy food industry and to determine the priorities of important logistics requirements (LR) based on customer requirements as a part of a supply management system. For product or service development quality function deployment (QFD) is a useful approach to maximize customer satisfaction. The determination of the priorities of the LR is an important issue during QFD process for product or service design. For this reason in this work an integrated approach integrating fuzzy logic and QFD methods is proposed to identify and prioritize the LR in dairy food industry for the improvement of customer satisfaction. In addition a case study in Turkish dairy food industry is given to illustrate the proposed approach for potential readers. In short the main contribution of the proposed approach with the case study is to help managers understand their customer requirements determine the related LR and rank them by weight in order to prioritize (i.e. determining the sequences of putting into action) for improving the level of customer satisfaction. © ExcelingTech Pub UK.Article Citation - WoS: 24Citation - Scopus: 32Fuzzy Ahp-Gra Approach To Evaluating Energy Sources: a Case of Turkey(EMERALD GROUP PUBLISHING LTD, 2020) Ayağ, Zeki; Samanlıoğlu, FundaPurpose Since the demand for energy has dramatically increased in the countries which have fast-growing population and economy, they have faced with a critical problem of how to evaluate a set of potential energy sources (i.e. nuclear, natural gas, bio, geothermal, hydro, wind and solar) and choose the ultimate energy source for their needs. On the other hand, this critical problem turns into a multiple-criteria decision-making (MCDM) in the presence of a set of energy source alternatives and evaluation criteria. In literature, there are many MCDM methods introduced to solve for different kinds of problems. The purpose of this paper is to present an integrated approach for evaluating energy sources using fuzzy AHP and GRA, with a case for Turkey. Design/methodology/approach In this paper, the analytic hierarchy process (AHP) and grey relational analysis (GRA) methods are used because of their advantages for similar problems. On the other hand, due to the fact that the conventional AHP by a nine-point scale and GRA method using a scale with crisp values can be unable to handle to capture the right judgments of a decision-maker(s), to reflect the vagueness and uncertainty on the judgments of a decision-maker, the fuzzy logic is integrated with the AHP and GRA. Findings The contributions of the paper to the literature are given in two dimensions as follows: it presents an integrated approach for complex decision processes with subjective data or vague information; the proposed approach, the fuzzy AHP-GRA method for energy source selection, is unique for the related problem in literature. The results of the proposed model from the case of Turkey will help practitioners and experts of how to apply it to the similar problems in the field of energy management. Social implications On the other hand, the proposed approach, the fuzzy AHP-GRA for energy source selection can also be an intelligent tool for public and private energy companies in Turkey, as well as others in the world. Originality/value On the other hand, in this paper, to the best of the authors' knowledge, the study contributes to the literature that the first time, they use the fuzzy alpha-cut AHP and GRA in fuzzy environment for energy source evaluation problem.Master Thesis Six Sigma Project Evaluation Under Fuzziness in Food Industry(Kadir Has Üniversitesi, 2013) Şentürk, Özlenen; Ayağ, Zeki; Kahraman, CengizModern-day business world is under constant development at production and service market. Common purpose is to return profit by optimizing costs and raise customer satisfaction to maintain acquired success. It is observed at processes that more service and production are provided by less work force. In food sector which is one of the best known service and production areas, if there will be a new production system "knowledge" should be used as base. On the other hand it is necessary to focus on food safety and customer satisfaction. It is obvious that Six Sigma approach is helpful to achieve this tradition. Statistically objective is to enhance performance at processes by reaching defect margin of 3,4 units at 1 million product or service. Six Sigma methodology provides cultural exchange on the way to improvement. Companies can do measurements by using quality control tools for topics like determining cost expenses. However these companies will have difficulties measuring customer satisfaction. Especially at food sector, performing measurements mostly brings along difficulties due to variable customer needs. In this connection it will be an important attempt to use "Fuzzy Logic". Fuzzy Logic is an artificial intelligence principle with variable outcomes which does not gives certain results like classic logic and datas are estimated. In this research, most suitable alternative and method is determined by Six Sigma project evaluation approach under Fuzzy Logic for 5 different selected food facilities in Turkey.Article Citation - WoS: 1Citation - Scopus: 3An Approach To Evaluate Cam Software Alternatives(TAYLOR & FRANCIS LTD, 2020) Ayağ, ZekiThe selection process for the best computer-aided manufacturing (CAM) software among a set of potential number of alternatives in market has been critical issue for most companies that aim to make their design/manufacturing-related activities automated. Because this selection process is very vital for companies because a wrong decision might put them into a difficult position in terms of economical, market share and time spent. Therefore, today's companies have used different multiple-criteria decision making (MCDM) methods for the evaluation study of CAM software alternatives to make this complex process easily applicable and not time-consuming. Among the MCDM methods in literature, the analytic hierarchy process (AHP) method has been widely used for various MCDM problems in both academic researches and industrial practices. However, in some cases, because of the vagueness and uncertainty on the judgments of decision maker(s), the crisp pair wise comparison in the conventional AHP seems to be insufficient and imprecise to capture the right judgments of decision maker(s). Therefore, a fuzzy logic method is integrated in the pair wise comparison of AHP to make up for this deficiency in the conventional AHP, called as fuzzy AHP. Moreover, the proposed approach is also realized on a case study.
