Decision Making Analysis and Modeling

Yöneticiliğin en temel işlevi karar vermektir. Bu durum işletme yöneticileri için de geçerlidir. Yönetim düzeylerinde yukarı çıkıldıkça verilen kararların önem ve etkileri de artar. Bir yönetici birçok ast ile çalışır ve bir karar verirken bunların fikirlerini alır ve onların uzmanlıklarından yararlanır. Karara ne kadar fazla katılım olur ne kadar fazla bakış açısından yararlanılırsa, kararın yanlış olması olasılığı azalır. Ancak, kararların sorumluluğunu nihai kararı veren yöneticiler taşır. Bu nedenle karar vermek  beraberinde sorumluluk getirir ve karar verene bazı psikolojik güçlükler yaratır. Geçmişte yöneticiler kararlarını bazı sezgisel yaklaşımlara dayandırmışlar ve sistematik yöntemleri gözardı etmişlerdir. Ancak, özellikle 20’nci yüzyılın ikinci yarısından itibaren, İkinci Dünya Savaşında edinilen tecrübeler ve bu savaşı takibeden yıllardaki teknolojik gelişmeler karar problemlerine sistematik bir yaklaşımın uygulanmasını gerekli kılmıştır. Bu gereksinmenin bir sonucu olarak Yöneylem Araştırması ile Sayısal Karar Verme Yöntemleri geliştirilmiştir. Bu kitap bunlardan ikincisi olan Sayısal Karar Verme Yöntemlerini konu edinmektedir.
Sayısal Karar Verme Yöntemleri, karar problemlerine rasyonel bir çözüm bulunabilmesi için gereken metodolojiyi ortaya koyar. Bu yöntemler kararın ne olması gerektiğinden ziyade nasıl karar verilmesi gerektiği üzerinde durur. Elinizdeki kitap hazırlanırken 1950’li yıllardan itibaren bu alanda yapılan çalışmalar ve temel eser niteliğindeki yayınlar incelenmiştir. Bu kitabın daha dar kapsamlı ilk versiyonu Karar Analizleri adıyla Kara Harp Okulu Basımevi tarafından basılmıştır. Bu ilk versiyonun çok kriterli karar verme bölümü geliştirilmiş ve değişik örnek olaylar eklenerek elinizdeki kitap oluşturulmuştur. Örnek olaylar oluşturulurken günlük hayatta karşılaşılabilecek olayların seçilmesine özen gösterilmiştir.
Sayısal Karar Verme Yöntemleri kitabı temel olarak üç ana bölümden oluşmaktadır. Birinci bölümde karar analizinin temelleri, ikinci bölümde tek kriterli karar problemlerinin analizi, üçüncü bölümde ise çok kriterli karar problemlerinin analizi üzerinde durulmaktadır.
Kitabın okuyucular için yararlı olması en büyük dileğimizdir. Kitapla ilgili görüş ve öneriler bizim için çok değerlidir. Görüş ve önerileri ile kitabın gelişmesine katkıda bulunacak değerli okuyuculara şimdiden teşekkür ederiz.

As a practical popular methodology for dealing with fuzziness and uncertainty in Multiple Criteria Decision-Making (MCDM), Fuzzy AHP (FAHP) has been applied to a wide range of applications. As of the time of writing there is no state of the art survey of FAHP, we carry out a literature review of 190 application papers (i.e., applied research papers), published between 2004 and 2016, by classifying them on the basis of the area of application, the identified theme, the year of publication, and so forth. The identified themes and application areas have been chosen based upon the latest state-of-the-art survey of AHP conducted by [Vaidya, O., & Kumar, S. (2006). Analytic hierarchy process: An overview of applications. European Journal of operational research, 169(1), 1–29.]. To help readers extract quick and meaningful information, the reviewed papers are summarized in various tabular formats and charts. Unlike previous literature surveys , results and findings are made available through an online (and free) testbed, which can serve as a ready reference for those who wish to apply, modify or extend FAHP in various applications areas. This online testbed makes also available one or more fuzzy pairwise comparison matrices (FPCMs) from all the reviewed papers (255 matrices in total).

In terms of results and findings, this survey shows that: (i) FAHP is used primarily in the Manufacturing, Industry and Government sectors; (ii) Asia is the torchbearer in this field, where FAHP is mostly applied in the theme areas of Selection and Evaluation; (iii) a significant amount of research papers (43% of the reviewed literature) combine FAHP with other tools, particularly with TOPSIS, QFD and ANP (AHP's variant); (iv) Chang's extent analysis method, which is used for FPCMs'weight derivation in FAHP, is still the most popular method in spite of a number of criticisms in recent years (considered in 57% of the reviewed literature).

In past years, the multi-attribute decision-making (MADM) approaches have been extensively applied by researchers to the supplier evaluation and selection problem. Many of these studies were performed in an uncertain environment described by fuzzy sets. This study provides a review of applications of MADM approaches for evaluation and selection of suppliers in a fuzzy environment. To this aim, a total of 339 publications were examined, including papers in peer-reviewed journals and reputable conferences and also some book chapters over the period of 2001 to 2016. These publications were extracted from many online databases and classified in some categories and subcategories according to the MADM approaches, and then they were analysed based on the frequency of approaches, number of citations, year of publication, country of origin and publishing journals. The results of this study show that the AHP and TOPSIS methods are the most popular approaches. Moreover, China and Taiwan are the top countries in terms of number of publications and number of citations, respectively. The top three journals with highest number of publications were: Expert Systems with Applications, International Journal of Production Research and The International Journal of Advanced Manufacturing Technology.

Evaluation of airlines based on service quality criteria can help to improve the processes of airlines, and also can give guidance to travel agencies to provide better choices for passengers and tourists. In this study, a hybrid simulation-based assignment approach is proposed to deal with multi-criteria decision-making problems with a group of decision-makers. A probability distribution is used to model decision-makers’ opinions and constructing a stochastic decision matrix. Then some efficient multi-criteria decision-making methods are utilized for evaluating alternatives in a simulation process. The proposed approach is applied to a problem of evaluation of five airlines with respect to opinions of 58 experts on 28 criteria. The results show the efficiency of the proposed to handle decision-making problems with a large number of experts. Moreover, the evaluation results are more reliable than the other decision-making approaches because of simulating decision-makers’ opinions, using multiple methods and evaluating based on aggregative results.

One of the important activities of a company that can increase its competitiveness is market segment evaluation and selection (MSE/MSS). We can usually consider MSE/MSS as a multi-criteria decision-making (MCDM) problem, and so we need to use an MCDM method to handle it. Uncertainty is one of the important factors that can affect the process of decision-making. Fuzzy MCDM approached have been designed to deal with the uncertainty of decision-making problems. In this study, a fuzzy extension of the CODAS (COmbinative Distance-based ASsessment) method is proposed to solve multi-criteria group decision-making problems. We use linguistic variables and trapezoidal fuzzy numbers to extend the CODAS method. The proposed fuzzy CODAS method is applied to an example of market segment evaluation and selection problem under uncertainty. To validate the results, a comparison is performed between the fuzzy CODAS and two other MCDM methods (fuzzy EDAS and fuzzy TOPSIS). A sensitivity analysis is also carried out to demonstrate the stability of the results of the fuzz CODAS. For this aim, ten sets of criteria weights are randomly generated and the example is solved using each set separately. The results of the comparison and the sensitivity analysis show that the proposed fuzzy CODAS method gives valid and stable results.

In the real-world problems, we are likely confronted with some alternatives that need to be evaluated with respect to multiple conflicting criteria. Multi-criteria decision-making (MCDM) refers to making decisions in such a situation. There are many methods and techniques available for solving MCDM problems. The evaluation based on distance from average solution (EDAS) method is an efficient multi-criteria decision-making method. Because the uncertainty is usually an inevitable part of the MCDM problems, fuzzy MCDM methods can be very useful for dealing with the real-world decision-making problems. In this study, we extend the EDAS method to handle the MCDM problems in the fuzzy environment. A case study of supplier selection is used to show the procedure of the proposed method and applicability of it. Also, we perform a sensitivity analysis by using simulated weights for criteria to examine the stability and validity of the results of the proposed method. The results of this study show that the extended fuzzy EDAS method is efficient and has good stability for solving MCDM problems.