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

Full item page

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 - 6 of 6

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: 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.
Citation - WoS: 116
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.
Citation - WoS: 45
Citation - Scopus: 59
A Hybrid Approach To Machine-Tool Selection Through Ahp and Simulation
(Taylor & Francis, 2007) Ayağ, Zeki; Ayağ, Zeki; Industrial Engineering
The selection process of a machine tool has been a critical issue for companies for years because the improper selection of a machine tool might cause many problems having a negative effect on productivity precision flexibility and a company's responsive manufacturing capabilities. Therefore in this paper to determine the best machine tool satisfying the needs and expectations of a manufacturing organization among a set of possible alternatives in the market a hybrid approach is proposed which integrates an analytic hierarchy process (AHP) with simulation techniques. The AHP as one of the most commonly used multiple criteria decision-making methods is used to narrow down all possible machine tool alternatives in the market by eliminating those whose scores (or weights) are smaller than a determined value obtained under certain circumstances. Then a simulation generator is used first to automatically model a manufacturing organization where the ultimate machine tool will be used and second to try each alternative remaining from the AHP as a scenario on the generated model. Finally the final alternative is selected by using the unit investment cost ratio which is calculated by dividing the investment cost per year of each alternative by the additional number of produced units obtained from the simulation experiment of the relevant alternative.
Citation - WoS: 12
Citation - Scopus: 17
A Combined Fuzzy Ahp-Goal Programming Approach To Assembly-Line Selection
(IOS Press, 2007) Ayağ, Zeki; Ayağ, Zeki; Özdemir, Rıfat Gürcan; Industrial Engineering
In mass production assembly-line balancing (ALB) problem has been a critical and repetitive issue for companies for long time. On the other hand equipment selection for stations has also been another important problem at the design stage of an assembly-line system. In this paper both problems are handled simultaneously. Therefore first goal programming (GP) method a well-suited technique is used to develop a preemptive formulation to joint both of the problems when the nature of the problem consists of several conflicting objectives and some mathematical constraints on solutions. Second an AHP method based on fuzzy scales which is incorporated with the GP is also used due to the fact that it takes both qualitative and quantitative judgments of decision-maker(s) into consideration to rank the equipment alternatives for stations by weight. The fuzzy AHP as one of the most commonly used multiple-criteria decision making (MCDM) methods has been effectively used for more than decade in both academic research and practice and takes the vagueness and uncertainty on judgments of decision-maker(s) into consideration due to the fact that the crisp pairwise comparison in the conventional AHP seems to insufficient and imprecise to capture the right judgments of decision-maker(s). In short in this study a combined fuzzy AHP-GP approach is proposed to evaluating assembly-line design alternatives with equipment selection. An integer GP formulation is constructed which also uses the fuzzy AHP scores of equipment alternatives and employs them as one of the goals. Then the mathematical model is solved to find out the ultimate alternative in terms of the minimized equipment cost and the maximized preference measures of decision-maker(s). The proposed approach is also illustrated on a sample case study.