Melike Erdoğan

A combined fuzzy approach to determine the best region for a nuclear power plant in Turkey

The location selection for nuclear power plant is a critical decision making problem.The fuzzy sets provide huge facilities to decision makers.To address ambiguities more conveniently, type-2 fuzzy sets have been used. When increase in energy needs of developing countries cannot be met by conventional energy sources, alternative energy sources are considered to substitute them. Nuclear energy that meets the needs of a greater proportion of energy demands for countries is one of effective alternative energy types. In this context, after deciding on the use of nuclear energy, the selection of the most suitable location for the production of nuclear power is one of the important decision making problems. In this paper, we performed a facility location selection model for Turkey in meeting the needs of energy with using new and unused source of nuclear energy. For this aim, a combined fuzzy multi criteria decision making (MCDM) methodology that consists of Interval type-2 fuzzy analytical hierarchy process (AHP) that is applied to determine weights of criteria and interval type-2 fuzzy TOPSIS that is applied for ranking alternatives is used to determine the best location alternative for the nuclear power plant. By the way, the obtained results have been analyzed depending upon the criteria that used for the evaluation process. The obtained results are compared with existing nuclear power plants location selection policy for Turkey and some suggestions have been made for the plants where would be the located are not decided. By the way, a sensitivity analysis has been conducted to analyze effects of changes in decisions parameters.

A New Extension of the ELECTRE Method Based Upon Interval Type-2 Fuzzy Sets for Green Logistic Service Providers Evaluation

Increase in environmental pollution makes companies give more importance to this issue, and as such, there is a need to take into account the necessary precautions. In particular, logistics service providers who are interwoven with the environment should apply some policies to increase environmental awareness. In this paper, we extended the ELECTRE method and proposed a new methodology for handling fuzzy multi criteria decision making problems based upon interval type-2 fuzzy sets. Interval type-2 fuzzy sets provided more df to reflect the uncertainty and the fuzziness of the real applications. An empirical study was presented in order to evaluate the green logistics service providers. A sensitivity analysis was applied to discuss and evaluate the greenness of the logistic service providers.

A hybrid fuzzy methodology to evaluate customer satisfaction in a public transportation system for Istanbul

Service quality (SERVQUAL) is one of the most important factors that increase the usage of public transportation. SERVQUAL improvements can solve many problems such as traffic congestion, air and noise pollution, and energy consumption in any public transportation system (PTS). In this paper, a hybrid fuzzy approach consisting of SERVQUAL, the Delphi method, fuzzy analytic hierarchy process (AHP) and fuzzy technique for order preference by similarity to ideal solution (TOPSIS) methodologies for the evaluation of SERVQUAL of PTS is presented. The SERVQUAL method is used for classifying the public transportation SERVQUAL evaluation criteria, the Delphi method is used to obtain the evaluations of experts, fuzzy AHP is used to determine the weights of the criteria and fuzzy TOPSIS is used to rank the alternatives. A new linguistic scale is taken into consideration while converting the linguistic evaluations of survey respondents to fuzzy numbers. The proposed approach is applied for the PTS in Istanbul, and the public transportation company that provides the highest customer satisfaction is determined. With this aim, four alternative companies named Istanbul Electric Tramway and Tunnel (IETT), Metrobus, Private Public Transportation Buses and Otobus Inc. are evaluated.

An extended fuzzy TOPSIS–GRA method based on different separation measures for green logistics service provider selection

In this paper, first, the criteria that make logistics service providers more “green” are determined as: cooperation with customer’s company and its customer, green government regulations, environmental management system, green process design, reduction in energy consumption and green network design. The criteria weights are determined by fuzzy AHP, based on expert opinions. Then, a new method is proposed, which is the combination of fuzzy TOPSIS and GRA, and used to evaluate green 3PLs based on different separation measures, as an extension, using trapezoidal fuzzy numbers. Five Turkish 3PLs serve in Istanbul are selected in order to apply a case study to show the applicability of the proposed method. Finally, the proposed method is verified with respect to different resolving coefficient values and separation measures and also compared with fuzzy TOPSIS and fuzzy VIKOR method results. Different multi-criteria decision-making methods can be applied and compared to check validity of our results for future studies. The proposed method can also be implemented to 3PLs in other countries.

Analysis and control of variability by using fuzzy individual control charts

Abstract The detection of changes in a process within shortest time provides significant benefits in terms of cost and quality. When considering the cost which would show up because of delays in identifying variability, detecting the deviation in the process accurately and quickly has a great importance for investors. In this paper, return volatility in the Borsa Istanbul-30 index (BIST-30) has been analyzed and a fuzzy control chart for individual measurements (FCCIM) has been proposed for use in determining and controlling in the variables of the BIST-30 index. For this purpose, firstly exponential smoothing method is used to forecast the variability of stock price of BIST-30 index by using MINITAB statistical software, and then a fuzzy control chart for individual measurements (FCCIM) which are fuzzy individual control chart (FICC) and fuzzy moving range control chart (FMRCC) with fuzzy control rules have been developed to be used in determining the variability of the process. For this aim, some fuzzy rules have been defined by using Ms EXCEL in fuzzy control chart for individual measurements. A real case application from Istanbul Stock Exchange for BIST-30 has been managed to check the effectiveness of suggested fuzzy control charts.

Selecting the Best Strategy for Industry 4.0 Applications with a Case Study

In this paper, we try to find the best strategy for Industry 4.0 implementation. For this aim, we determine the aggregated strategies for applying this concept and criteria that are used to select the best strategy. With the criteria set out in this context, basic strategies should be applied as a priority, considering for example human resources, work organization and design, information systems, and effective use of resources, and the development of new business models and standardization are specified. Since this selection is a process in which many different measures need to be considered, multi-criteria decision-making (MCDM) methods based on AHP-VIKOR methodologies have been applied to find the best strategy. Fuzzy set theory was beneficial for coping with uncertainties in the selection process.

Location selection of electric vehicles charging stations by using a fuzzy MCDM method: a case study in Turkey

Pollution, climate change, fast natural resource depletion, deforestation and global warming have become major worldwide problems relevant with the petroleum-based powered vehicles and alternatives for this conventional transportation type have been started to change in the last decade. In this modification process, electric vehicles (EVs) have a leading position due to their low damage effect to the environment. Selecting the most sustainable location for charging station for EVs plays an important role in the life cycle of them. This process needs to consider some conflicting criteria and has a complex decision problem that can be modeled as a multi-criteria decision-making problem. The inclusion of such criteria in a location selection requires the fuzzy sets to be used in the decision-making methodology. For this aim, intuitionistic fuzzy sets have been used in this paper. By the way, a decision-making procedure based on intuitionistic fuzzy sets and consists of the decision-making trial and evaluation laboratory, analytic hierarchy process and technique for order preference by similarity to ideal solution has been suggested for the location selection of charge stations. The proposed fuzzy-based model is applied to a case study for Istanbul in Turkey.

ÇOK KRİTERLİ KARAR VERME YAKLAŞIMI İLE PERSONEL SAYISININ DENGELENMESİ: BİR KAMU ÜNİVERSİTESİ İÇİN GERÇEK HAYAT UYGULAMASI

Bir universitede idari sureclerin zamaninda ve etkin bir sekilde islemesi, ogrencileri, akademisyenleri hatta etkilesimde oldugu diger universiteleri de etkiler. Bu etkinligin saglanabilmesi icin fakulteler ve bolumler bazinda en uygun personel sayisinin bulunmasi buyuk onem arz etmektedir. Bu calismada bir kamu universitesinde fakulteler ve bolumler bazinda en uygun idari personel sayisinin belirlenmesi ve var olan personelin bu analize gore dagitimi gerceklestirilmistir. Oncelikle mevcut durum analizi yapilmis, ardindan personel ihtiyaci veya fazlasi bulunan fakulteler/bolumler belirlenerek personel kaydirma islemi uygulanmistir. Is yuklerinin saptanmasinda, birimsel yuk agirliklarinin belirlenmesinde oldukca yaygin basvurulan Analitik Hiyerarsi Sureci (AHS) kullanilarak islerin birbirlerine gore agirliklari hesaplanmistir. Calisma genel anlamiyla bir personel cizelgeleme problemi olarak ele alinabilir. Ancak sunulan problemin klasik bir personel cizelgeleme probleminden farkinin temel olarak, zamani goz onunde bulundurarak personeli vardiyalara gore atamak degil, var olan personeli standart calisma saatleri icin is yukune gore dagitmak ve birimler bazinda en uygun personel sayisini elde etmek oldugu soylenebilir. Analiz sonucunda, bolum ve dekanliklar bazinda eldeki personel ile dengenin saglanip saglanmadigi ve ek personele ihtiyac duyulup duyulmadigi arastirilmistir.

A fuzzy multi-criteria decision making approach for choosing a logistics center location in Turkey

Location selection of a logistics center is one of decision-making problems involving uncertainty. In order to reflect uncertainties in the selection process, fuzzy logic is usually applied. For this aim, we used a fuzzy decision making methodology for choosing a logistics center location. In this paper, location selection problem for a logistics center has been examined for the Eastern Anatolia Region in Turkey. For this aim, cities named Malatya, Erzurum and Van identified as alternatives and four main and six sub-criteria are identified to assess the priorities of these cities. As a result, the best logistics center location alternative has been determined for the eastern Anatolia region.

A Hybrid Fuzzy Decision Making Procedure to Select among Outsourcing Alternatives for Waste of Electrical and Electronic Equipment

Municipality and they are ranked according to the closeness coefficients that obtained by the proposed method. Finally the most appropriate outsourcing firm for waste of electrical and electronic equipment is determined for metropolitan municipality.