Ayağ, Zeki
Loading...
Profile URL
Name Variants
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
15
LIFE ON LAND
0
Research Products
16
PEACE, JUSTICE AND STRONG INSTITUTIONS
0
Research Products
14
LIFE BELOW WATER
0
Research Products
6
CLEAN WATER AND SANITATION
0
Research Products
3
GOOD HEALTH AND WELL-BEING
0
Research Products
17
PARTNERSHIPS FOR THE GOALS
0
Research Products
4
QUALITY EDUCATION
0
Research Products
2
ZERO HUNGER
0
Research Products
10
REDUCED INEQUALITIES
0
Research Products
7
AFFORDABLE AND CLEAN ENERGY
6
Research Products
13
CLIMATE ACTION
0
Research Products
1
NO POVERTY
0
Research Products
9
INDUSTRY, INNOVATION AND INFRASTRUCTURE
8
Research Products
12
RESPONSIBLE CONSUMPTION AND PRODUCTION
0
Research Products
8
DECENT WORK AND ECONOMIC GROWTH
2
Research Products
11
SUSTAINABLE CITIES AND COMMUNITIES
0
Research Products
5
GENDER EQUALITY
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
351/4943
Supervised MSc Theses
5
Supervised PhD Theses
1
WoS Citation Count
1027
Scopus Citation Count
1483
WoS h-index
16
Scopus h-index
19
Patents
0
Projects
0
WoS Citations per Publication
22.82
Scopus Citations per Publication
32.96
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
Conference Object Citation - Scopus: 4Determining Master Schedule of Surgical Operations by Integer Programming: a Case Study(Institute of Industrial Engineers, 2010) Samanlıoğlu, Funda; Ayağ, Zeki; Batili, Burcin; Evcimen, Esra; Yılmaz, Gulsah; Atalay, OzlemFixed amounts of available Operating Room (OR) time compatibility of ORs and restrictions related to surgery equipment and surgeon availabilities complicate the process of preparing the master surgical schedule at hospitals. In this research an integer programming model and its application at Etiler World Eye Hospital (in Turkey) are presented in order to create a master surgical schedule that includes the most common surgery types on weekly basis and resolves surgeon equipment and operating room restriction and availability issues. The integer programming model utilizes the available OR time at the hospital by minimizing the total underallocation of OR time with respect to targeted OR time of surgeons taking into consideration surgeon equipment and OR restrictions and availabilities. The mathematical model is then solved using a commercial solver to obtain a weekly master surgical schedule for the hospital.Doctoral Thesis Building a Framework for Adopting Lean Principles To Achieve Sustainability in Solar Energy Firms: Turkiye as a Case Study(Kadir Has Üniversitesi, 2022) Aldewachi, Bilal; Zeki AyağThe two terms lean, and sustainability have become one of the most important terms in the field of business because of their role in developing the work in line with increasing profits on the one hand and taking into account the future on the other. Solar energy firms are witnessing great competition to meet energy requirements and suffering from a huge amount of waste, which negatively affects in achieving sustainability. Hence, this study aims to build a framework for solar energy firms to achieve sustainability dimensions through adopting lean principles. The framework will help to solve problems that the solar energy sector is facing. The method in the study included reviewing the literature to examine the founding of the relation between lean and sustainability and using a questionnaire that was directed to the responsible people in Turkish solar energy companies. The results of the survey were analyzed to (1) Discover what the people in charge in solar energy firms think about lean and sustainability; (2) Measure the possible relationship between lean principles and sustainability dimensions by applying a linear regression and non-linear regression test; (3) Using the results of the second point to build the framework. The final results indicated a high level of the relative importance of the two terms from the perspective of the people in charge in the solar energy firms. Besides, the study found a relationship between adopting the two principles of lean, pull, and flow and achieving economic, social resources, and technology dimensions of sustainability; this finding is represented in a framework.Article Citation - WoS: 17Citation - Scopus: 22An Intelligent Approach To Supplier Evaluation in Automotive Sector(Springer, 2016) Ayağ, Zeki; Samanlıoğlu, FundaDuring the process of supplier evaluation selecting the best desirable supplier is one of the most critical problems of companies since improperly selected suppliers may cause losing time cost and market share of a company. For this multiple-criteria decision making selection problem in this paper a fuzzy extension of analytic network process (ANP) which uses uncertain human preferences as input information in the decision-making process is applied since conventional methods such as analytic hierarchy process cannot accommodate the variety of interactions dependencies and feedback between higher and lower level elements. The resulting fuzzy ANP enhances the potential of the conventional ANP for dealing with imprecise and uncertain human comparison judgments. In short in this paper an intelligent approach to supplier selection problem through fuzzy ANP is proposed by taking into consideration quantitative and qualitative elements to evaluate supplier alternatives and a case study in automotive sector is presented.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 - Scopus: 31Fuzzy Ahp-Gra Approach To Evaluating Energy Sources: a Case of Turkey(Emerald Group Holdings Ltd., 2020) Ayağ,Z.; Samanlioglu,F.Purpose: 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. Research limitations/implications: In short, in this paper, an integrated approach is proposed through the fuzzy AHP and the fuzzy GRA methods. As the fuzzy AHP is used to determine the weights of evaluation criteria, the fuzzy GRA is used to rank energy source alternatives. Practical implications: In addition, a case study for Turkey is presented to show the applicability of the proposed approach for potential practitioners who are authority in the field of energy in public and private sectors. 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. © 2019, Emerald Publishing Limited.Article Citation - WoS: 28Citation - Scopus: 30A Hesitant Fuzzy Linguistic Terms Set-Based Ahp-Topsis Approach To Evaluate Erp Software Packages(Emerald Group Publishing Ltd, 2020) Ayağ, Zeki; Samanlıoğlu, FundaPurpose In this paper, two popular multiple-criteria decision-making (MCDM) methods with hesitant fuzzy logic approach; hesitant fuzzy analytic hierarchy process (hesitant F-AHP) and hesitant fuzzy the technique for order preference by similarity to ideal solution (HF-TOPSIS) are integrated as HF-AHP-TOPSIS to evaluating a set of enterprise resource planning (ERP) alternatives and rank them by weight to reach to the ultimate one that satisfies the needs and expectations of a company. Design/methodology/approach Selecting the best ERP software package among the rising number of the options in market has been a critical problem for most companies for a long time because of the reason that an improper ERP software package might lead to many issues (i.e. time loss, increased costs and a loss of market share). On the other hand, finding the best ERP alternative is a comprehensive MCDM problem in the presence of a set of alternatives and several potentially competing quantitative and qualitative criteria. Findings In this integrated approach, the hesitant F-AHP is used to determine the criteria weights, as the hesitant F-TOPSIS is utilized to rank ERP package alternatives. The proposed approach was also validated in a numerical example that has five ERP package alternatives and 12 criteria by three decision-makers in order to show its applicability to potential readers and practitioners. Research limitations/implications If the number of the alternatives and criteria are dramatically increased beyond reasonable numbers, the reaching to final solution will be so difficult because of the great deal of fuzzy based calculations. Therefore, the number of criteria and alternatives should be at reasonable numbers. Practical implications The proposed approach was also validated in a illustrated example with the five ERP package options and 12 criteria by the three decision-makers in order to show its applicability to potential readers and practitioners. Originality/value Furthermore, in literature, to the best of our knowledge, the authors did not come cross any work that integrates the HF-AHP with the HF-TOPSIS for ERP software package selection problem.Master Thesis Energy Trading in Turkish Power Market Through Options Bileteral Agreements and Spot Market(Kadir Has Üniversitesi, 2013) Tasdemir, Ecem Ezgi; Ayağ, Zekiin today’s world electricity energy which has a vital place in energy market is irreplaceable in any field because of being the basic entry in production factors and because of continuous increasing demand to electricity thanks to technological development. Especially in our country which has a rapid acceleration for the last decade by reorganizing Electricity Energy Market it is aimed to build a competitive structure in production and retail transactions. Also with the process of development in Turkey the structure of the market changed varied and created different alternatives for efficient buying-selling transactions. in this work we built a model on the purpose to find the solution of the most efficient scenarios and maximum efficiency by using electricity spot market which has transactions with a determined capacity limit derivatives market and bilateral agreements. The amount of efficiency is calculated by using the Model for each 100 different power scenarios’ in Excel and the results are got and interpreted. As a result of this the most efficient scenario determined. -- Abstract'tanArticle Citation - WoS: 2Citation - Scopus: 3Achieving Sustainability in Solar Energy Firms in Turkey Through Adopting Lean Principles(Mdpi, 2022) Aldewachi, Bilal; Ayag, ZekiLean 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.Article Citation - WoS: 16Citation - Scopus: 18An Intelligent Approach for the Evaluation of Innovation Projects(IOS Press, 2020) Samanlıoğlu, Funda; Ayağ, ZekiIn this study, an intelligent approach is presented for the evaluation and selection of innovation projects. Selecting the best innovation project is a complicated multiple criteria decision making (MCDM) problem with several potentially competing quantitative and qualitative criteria. In this paper, two hesitant fuzzy MCDM methods; hesitant fuzzy Analytic Hierarchy Process (hesitant F-AHP) and hesitant fuzzy VIsekriterijumska optimizacija i KOmpromisno Resenje (hesitant F-VIKOR) are integrated to evaluate and rank innovation projects. In the hesitant fuzzy AHP-VIKOR, hesitant F-AHP is used to find fuzzy evaluation criteria weights and hesitant F-VIKOR is implemented to rank innovation project alternatives. A numerical example is given where five innovation projects are evaluated based on nine criteria by three decision makers.Article Citation - Scopus: 89An Analytic Network Process-Based Approach To Concept Evaluation in a New Product Development Environment(Taylor & Francis, 2007) Ayağ, Zeki; Özdemir, Rifat GürcanSelecting the best product concept is one of the most critical tasks in a new product development (NPD) environment. Making decisions at this stage becomes very difficult due to imprecise and uncertain product requirements. So the evaluation process of determining the most satisfying conceptual design has been a very vital issue for companies to survive in fast-growing markets for a long time. Therefore most companies have used various methods to successfully carry out this difficult and time-consuming process. Of these methods an analytic hierarchy process (AHP) has been widely used in multiple-criteria decision-making problems (i.e. concept selection equipment evaluation). In this study however we use an analytic network process (ANP) a more general form of AHP due to the fact that AHP cannot accommodate the variety of interactions dependencies and feedback between higher and lower level elements. Briefly in this paper an ANP-based approach is presented to evaluate a set of conceptual design alternatives in order to reach to the best concept satisfying the needs and expectations of both customers and company. In addition a numerical example is presented to illustrate the proposed approach.
