Ayağ, Zeki

Ayağ, Zeki

Name Variants

Ayağ, Zeki
Z.,Ayağ
Z. Ayağ
Zeki, Ayağ
Ayag, Zeki
Z.,Ayag
Z. Ayag
Zeki, Ayag
Ayağ,Z.
Zeki Ayağ

Job Title

Prof. Dr.

Email Address

Zekıa@khas.edu.tr

Main Affiliation

Industrial Engineering

Status

Former Staff

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Sustainable Development Goals Report Points

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Scholarly Output

44

Articles

31

Citation Count

0

Supervised Theses

5 Scholarly Output Search Results

Now showing 1 - 10 of 26

Citation - WoS: 0
Citation - Scopus: 1
An Intelligent Approach To Cam Software Selection
(IEEE, 2012) Ayağ, Zeki; Ayağ, Zeki; Industrial Engineering
In this paper an intelligent approach is presented to help the companies select most suitable CAM software for their current and future needs. For this purpose fuzzy AHP method is used to carry out CAM selection process more effectively easily and applicable for a company. Shortly the objectives of the research are
Citation - Scopus: 87
An Analytic Network Process-Based Approach To Concept Evaluation in a New Product Development Environment
(Taylor & Francis, 2007) Ayağ, Zeki; Ayağ, Zeki; Özdemir, Rifat Gürcan; Industrial Engineering
Selecting 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.
Citation - WoS: 15
Citation - Scopus: 20
A Combined Fuzzy Ahp-Simulation Approach To Cad Software Selection
(Taylor & Francis Ltd, 2010) Ayağ, Zeki; Ayağ, Zeki; Industrial Engineering
In this paper a combined approach where the fuzzy analytic hierarchy process (AHP) and simulation come together is presented to select the best computer-aided design (CAD) software out of the available options in the market. The fuzzy AHP is used due to the vagueness and uncertainty of the judgements of a decision maker(s) because the crisp pair-wise comparison in the conventional AHP seems to be insufficient and imprecise to capture the right judgements of the decision maker(s). In this study first the fuzzy AHP is used to reduce a possible number of alternatives for the CAD system to an acceptable level for further study simulation analysis. Secondly a simulation generator as an integrated part of the fuzzy AHP is used to try the remaining alternatives on the generated model of a real-life product organisation in which the final alternative will be used. The results of simulation experiments are obtained and then evaluated to reach to the ultimate CAD alternative.
Minimizing the Defect Rate Using Six Sigma Dmaic Method; a Case Study in Supsan A.ş.
(Kadir Has Üniversitesi, 2016) Aslan, Nazmiye Yağmur; Ayağ, Zeki; Ayağ, Zeki; Industrial Engineering
Today 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%.
Citation - WoS: 17
Citation - Scopus: 20
An Intelligent Approach To Supplier Evaluation in Automotive Sector
(Springer, 2016) Ayağ, Zeki; Samanlıoğlu, Funda; Samanlıoğlu, Funda; Ayağ, Zeki; Industrial Engineering
During 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.
Citation - WoS: 1
Citation - Scopus: 1
Achieving Sustainability in Solar Energy Firms in Turkey Through Adopting Lean Principles
(Mdpi, 2022) Aldewachi, Bilal; Ayağ, Zeki; Ayag, Zeki; Industrial Engineering
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 - WoS: 231
Citation - Scopus: 307
A Fuzzy Ahp Approach To Evaluating Machine Tool Alternatives
(Springer, 2006) Ayağ, Zeki; Ayağ, Zeki; Özdemir, Rifat Gürcan; Industrial Engineering
Selecting process of a machine tool has been very important issue for companies for years because the improper selection of a machine tool might cause of many problems affecting negatively on productivity precision flexibility and company's responsive manufacturing capabilities. On the other hand selecting the best machine tool from its increasing number of existing alternatives in market are multiple-criteria decision making (MCDM) problem in the presence of many quantitative and qualitative attributes. Therefore in this paper an analytic hierarchy process (AHP) is used for machine tool selection problem due to the fact that it has been widely used in evaluating various kinds of MCDM problems in both academic researches and practices. However due to the vagueness and uncertainty on judgments of the decision-maker(s) the crisp pair wise comparison in the conventional AHP seems to insufficient and imprecise to capture the right judgments of decision-maker(s). That is why
Citation - WoS: 139
Citation - Scopus: 177
A Hybrid Approach To Concept Selection Through Fuzzy Analytic Network Process
(Pergamon-Elsevier Science Ltd, 2009) Ayağ, Zeki; Ayağ, Zeki; Özdemir, Rıfat Gürcan; Industrial Engineering
Evaluating conceptual design alternatives in a new product development (NPD) environment has been one of the most critical issues for many companies which try to survive in the fast-growing world markets. Therefore most companies have used various methods to successfully carry out this difficult and time-consuming evaluation process. Of these methods analytic hierarchy process (AHP) has been widely used in multiple-criteria decision-making (MCDM) problems. But in this study we used analytical network process (ANP) a more general form of AHP instead of AHP due to the fact that AHP cannot accommodate the variety of interactions dependencies and feedback between higher and lower level elements. Furthermore in some cases due to the vagueness and uncertainty on the judgments of a decision-maker the crisp pairwise comparison in the conventional ANP is insufficient and imprecise to capture the right judgments of the decision-maker. Therefore a fuzzy logic is introduced in the pairwise comparison of ANP to make up for this deficiency in the conventional ANP and is called as fuzzy ANP. In short in this paper a fuzzy ANP-based approach is proposed to evaluate a set of conceptual design alternatives developed in a NPD environment in order to reach to the best one satisfying both the needs and expectations of customers and the engineering specifications of company. In addition a numerical example is presented to illustrate the proposed approach. (C) 2008 Elsevier Ltd. All rights reserved.
Energy Trading in Turkish Power Market Through Options Bileteral Agreements and Spot Market
(Kadir Has Üniversitesi, 2013) Tasdemir, Ecem Ezgi; Ayağ, Zeki; Ayağ, Zeki; Industrial Engineering
in 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'tan
Citation - WoS: 115
Citation - Scopus: 152
An Intelligent Approach To Erp Software Selection Through Fuzzy Anp
(Taylor & Francis, 2007) Ayağ, Zeki; Ayağ, Zeki; Özdemir, Rıfat Gürcan; Industrial Engineering
During the implementations of enterprise resource planning (ERP) systems most companies have experienced some problems one of which is how to determine the best ERP software satisfying their needs and expectations. Because improperly selected ERP software may have an impact on the time required and the costs and market share of a company selecting the best desirable ERP software has been the most critical problem for a long time. On the other hand selecting ERP software is a multiple-criteria decision-making (MCDM) problem and in the literature many methods have been introduced to evaluate this kind of problem one of which is the analytic hierarchy process (AHP) which has been widely used in MCDM selection problems. However in this paper we use a fuzzy extension of an analytic network process (ANP) a more general form of AHP which uses uncertain human preferences as input information in the decision-making process because the AHP cannot accommodate the variety of interactions dependencies and feedback between higher- and lower-level elements. Instead of using the classical eigenvector prioritization method in the AHP only employed in the prioritization stage of ANP a fuzzy-logic method providing more accuracy on judgements is applied. The resulting fuzzy ANP enhances the potential of the conventional ANP for dealing with imprecise and uncertain human comparison judgements. In short in this paper an intelligent approach to ERP software selection through a fuzzy ANP is proposed by taking into consideration quantitative and qualitative elements to evaluate ERP software alternatives.