Beyza Ahlatcioglu Ozkok | Yildiz Technical University (original) (raw)

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Papers by Beyza Ahlatcioglu Ozkok

Scientia Iranica

The Linear Fractional Programming (LFP) problem that optimizes the ratio of two linear objective ... more The Linear Fractional Programming (LFP) problem that optimizes the ratio of two linear objective functions under linear constraints has a wide range of application areas. Based on the traditional definition of continuity, we developed an exact iterative algorithm that does not depend on big-M coefficients. Removing the nonlinearity in the fractional objective function by converting the objective function into a linear form, an equivalent linear-iterative problem is obtained and a computationally efficient algorithm is proposed. We also analyze the unbounded and asymptotic solution case of the LFP. To demonstrate the efficiency of the proposed method, illustrative numerical examples are provided for all solution cases. Also, we analyze the validity of our algorithm and compare our results with the existing algorithm from the literature by generating random large-scale test problems.

Pakistan Journal of Statistics and Operation Research, 2022

The linear fractional transportation problem (LFTP) is widely encountered as a particular type of... more The linear fractional transportation problem (LFTP) is widely encountered as a particular type of transportation problem (TP) in real-life. In this paper, a novel algorithm, based on the traditional definition of continuity, is presented to solve the LFTP. An iterative constraint is constructed by combining the objective function of the LFTP and the supply-demand condition since the fractional objective function is continuous at every point of the feasible region. By this constraint obtained, LFTP is converted into an iterative linear programming (LP) problem to reach the optimum solution. In this study, the case of asymptotic solution for LFTP is discussed for the first time in the literature. The numerical examples are performed for the linear and asymptotic cases to illustrate the method, and the approach proposed is compared with the other existing methods to demonstrate the efficiency of the algorithm. Also, an application had environmentalist objective is solved by proposed ma...

Proceedings of the International Conference on Applied Research in Management, Business and Economics, 2019

Evaluation of investment alternatives, taking effective and efficient investment decisions are on... more Evaluation of investment alternatives, taking effective and efficient investment decisions are one of the most important problems of our lives. Portfolio selection problem, can be described as one of the decision-making problem that is to decide which stocks are to be chosen for investment and in what proportions they will be bought. Analytical hierarchy process (AHP) is one of the very well-known multi criteria decision making techniques. Lately many extensions are proposed for AHP in order to handle fuzziness of real life problems by researchers. The most novel extension is to use interval type 2 fuzzy numbers for evaluation matrices in fuzzy AHP. In this study, we worked on portfolio selection problem and used type 2 fuzzy AHP in order to solve the problem and provided a case study on Borsa Istanbul (BIST).

Interdisciplinary Perspectives on Operations Management and Service Evaluation

Analytic hierarchy process (AHP) is a widely used multi-attribute decision-making (MADM) approach... more Analytic hierarchy process (AHP) is a widely used multi-attribute decision-making (MADM) approach. Due to the complexity and uncertainty involved in real world problems, decision makers might be prefer to make fuzzy judgments instead of crisp ones. Furthermore, even when people use the same words, individual judgments of events are invariably subjective, and the interpretations that they attach to the same words may differ. This is why fuzzy numbers has been introduced to characterize linguistic variables. Fuzzy AHP methods have recently been extended by using type-2 fuzzy sets. Type-2 fuzzy set theory incorporates the uncertainty of membership functions into the fuzzy set theory. In this chapter, the authors firstly provide a short review on applications of interval type-2 fuzzy AHP on MADM problems. Then, they present a very efficient MADM technique, interval type-2 fuzzy AHP, to solve the portfolio selection problem that is to decide which stocks are to be chosen for investment a...

Journal of Intelligent & Fuzzy Systems

Decision making (DM) is an important process encountered in every moment of life. Since it is dif... more Decision making (DM) is an important process encountered in every moment of life. Since it is difficult to interpret life depending on a single criterion, Multi-Criteria Decision Making (MCDM) enables to make decisions easier by creating appropriate choice in situations of uncertainty, complexity, and conflicting objectives. Therefore, we have studied the Analytic Hierarchy Process (AHP) which is one of the MCDM methods based on binary comparison logic. When uncertainties concerning the nature of life are considered, the solution procedure of AHP has been addressed by using Interval Type-2 Fuzzy Numbers (IT2FN)s to obtain more realistic results. The usability of AHP with IT2FN is increased by amplifying hierarchy with sub-levels. Since sub-criterion may also need to be evaluated on sub-criteria in some cases of real multi-criteria problems, it is explicitly essential that each of sub-sub-criterion is included in the hierarchy at the own level in the real sense. In this paper, a new ...

Operations Research and Decisions

By the green point of view, supply chain management (SCM), which contains supplier and location s... more By the green point of view, supply chain management (SCM), which contains supplier and location selection, production, distribution, and inventory decisions, is an important subject being examined in recent years by both practitioners and academicians. In this paper, the closed-loop supply chain (CLSC) network that can be mutually agreed by meeting at the level of common satisfaction of conflicting objectives is designed. We construct a multi-objective mixed-integer linear programming (MOMILP) model that allows decision-makers to more effectively manage firms’ closed-loop green supply chain (SC). An ecological perspective is brought by carrying out the recycling, remanufacturing and destruction to SCM in our proposed model. Maximize the rating of the regions in which they are located, minimize total cost and carbon footprint are considered as the objectives of the model. By constructing our model, the focus of customer satisfaction is met, as well as the production, location of faci...

Computers & Industrial Engineering

Journal of Intelligent & Fuzzy Systems

Journal of Intelligent & Fuzzy Systems, 2016

Journal of Intelligent & Fuzzy Systems, 2016

Enterprise Business Modeling, Optimization Techniques, and Flexible Information Systems, 2013

Handbook of Combinatorial Optimization, 2013

Expert Systems With Applications, Sep 1, 2011

Supplier selection problem is a multi-criteria decision making problem which includes both qualit... more Supplier selection problem is a multi-criteria decision making problem which includes both qualitative and quantitative factors. In the selection process many criteria may conflict with each other, therefore decision-making process becomes complicated. In this paper, we ...

Scientia Iranica

The Linear Fractional Programming (LFP) problem that optimizes the ratio of two linear objective ... more The Linear Fractional Programming (LFP) problem that optimizes the ratio of two linear objective functions under linear constraints has a wide range of application areas. Based on the traditional definition of continuity, we developed an exact iterative algorithm that does not depend on big-M coefficients. Removing the nonlinearity in the fractional objective function by converting the objective function into a linear form, an equivalent linear-iterative problem is obtained and a computationally efficient algorithm is proposed. We also analyze the unbounded and asymptotic solution case of the LFP. To demonstrate the efficiency of the proposed method, illustrative numerical examples are provided for all solution cases. Also, we analyze the validity of our algorithm and compare our results with the existing algorithm from the literature by generating random large-scale test problems.

Pakistan Journal of Statistics and Operation Research, 2022

The linear fractional transportation problem (LFTP) is widely encountered as a particular type of... more The linear fractional transportation problem (LFTP) is widely encountered as a particular type of transportation problem (TP) in real-life. In this paper, a novel algorithm, based on the traditional definition of continuity, is presented to solve the LFTP. An iterative constraint is constructed by combining the objective function of the LFTP and the supply-demand condition since the fractional objective function is continuous at every point of the feasible region. By this constraint obtained, LFTP is converted into an iterative linear programming (LP) problem to reach the optimum solution. In this study, the case of asymptotic solution for LFTP is discussed for the first time in the literature. The numerical examples are performed for the linear and asymptotic cases to illustrate the method, and the approach proposed is compared with the other existing methods to demonstrate the efficiency of the algorithm. Also, an application had environmentalist objective is solved by proposed ma...

Proceedings of the International Conference on Applied Research in Management, Business and Economics, 2019

Evaluation of investment alternatives, taking effective and efficient investment decisions are on... more Evaluation of investment alternatives, taking effective and efficient investment decisions are one of the most important problems of our lives. Portfolio selection problem, can be described as one of the decision-making problem that is to decide which stocks are to be chosen for investment and in what proportions they will be bought. Analytical hierarchy process (AHP) is one of the very well-known multi criteria decision making techniques. Lately many extensions are proposed for AHP in order to handle fuzziness of real life problems by researchers. The most novel extension is to use interval type 2 fuzzy numbers for evaluation matrices in fuzzy AHP. In this study, we worked on portfolio selection problem and used type 2 fuzzy AHP in order to solve the problem and provided a case study on Borsa Istanbul (BIST).

Interdisciplinary Perspectives on Operations Management and Service Evaluation

Analytic hierarchy process (AHP) is a widely used multi-attribute decision-making (MADM) approach... more Analytic hierarchy process (AHP) is a widely used multi-attribute decision-making (MADM) approach. Due to the complexity and uncertainty involved in real world problems, decision makers might be prefer to make fuzzy judgments instead of crisp ones. Furthermore, even when people use the same words, individual judgments of events are invariably subjective, and the interpretations that they attach to the same words may differ. This is why fuzzy numbers has been introduced to characterize linguistic variables. Fuzzy AHP methods have recently been extended by using type-2 fuzzy sets. Type-2 fuzzy set theory incorporates the uncertainty of membership functions into the fuzzy set theory. In this chapter, the authors firstly provide a short review on applications of interval type-2 fuzzy AHP on MADM problems. Then, they present a very efficient MADM technique, interval type-2 fuzzy AHP, to solve the portfolio selection problem that is to decide which stocks are to be chosen for investment a...

Journal of Intelligent & Fuzzy Systems

Decision making (DM) is an important process encountered in every moment of life. Since it is dif... more Decision making (DM) is an important process encountered in every moment of life. Since it is difficult to interpret life depending on a single criterion, Multi-Criteria Decision Making (MCDM) enables to make decisions easier by creating appropriate choice in situations of uncertainty, complexity, and conflicting objectives. Therefore, we have studied the Analytic Hierarchy Process (AHP) which is one of the MCDM methods based on binary comparison logic. When uncertainties concerning the nature of life are considered, the solution procedure of AHP has been addressed by using Interval Type-2 Fuzzy Numbers (IT2FN)s to obtain more realistic results. The usability of AHP with IT2FN is increased by amplifying hierarchy with sub-levels. Since sub-criterion may also need to be evaluated on sub-criteria in some cases of real multi-criteria problems, it is explicitly essential that each of sub-sub-criterion is included in the hierarchy at the own level in the real sense. In this paper, a new ...

Operations Research and Decisions

By the green point of view, supply chain management (SCM), which contains supplier and location s... more By the green point of view, supply chain management (SCM), which contains supplier and location selection, production, distribution, and inventory decisions, is an important subject being examined in recent years by both practitioners and academicians. In this paper, the closed-loop supply chain (CLSC) network that can be mutually agreed by meeting at the level of common satisfaction of conflicting objectives is designed. We construct a multi-objective mixed-integer linear programming (MOMILP) model that allows decision-makers to more effectively manage firms’ closed-loop green supply chain (SC). An ecological perspective is brought by carrying out the recycling, remanufacturing and destruction to SCM in our proposed model. Maximize the rating of the regions in which they are located, minimize total cost and carbon footprint are considered as the objectives of the model. By constructing our model, the focus of customer satisfaction is met, as well as the production, location of faci...

Computers & Industrial Engineering

Journal of Intelligent & Fuzzy Systems

Journal of Intelligent & Fuzzy Systems, 2016

Journal of Intelligent & Fuzzy Systems, 2016

Enterprise Business Modeling, Optimization Techniques, and Flexible Information Systems, 2013

Handbook of Combinatorial Optimization, 2013

Expert Systems With Applications, Sep 1, 2011

Supplier selection problem is a multi-criteria decision making problem which includes both qualit... more Supplier selection problem is a multi-criteria decision making problem which includes both qualitative and quantitative factors. In the selection process many criteria may conflict with each other, therefore decision-making process becomes complicated. In this paper, we ...