Decision Making On Service Purchasing Based On Fuzzy Soft Set Theory

With the rapid development of service economy and refined social division of labor, more and more companies outsource their non-core business to improve their competitiveness in the growing market. The rapid development in the scale, scope, and cost of enterprise service procurement has lead to higher requirements in the process of service procurement. The purpose of the study is to cope with the increasing frequency and the importance of service purchasing and reduce costs in service purchasing. The decision-making models of service purchasing are established, including one service procurement pattern selection model and two service provider selection models. The proposed models and methods can guide the enterprises in the efficiency and the quality of service procurement as well.First, the typical modes of procurement and the characteristics of service procurement are summarized. According to the ideas of purchasing classification, the factors that have effects on selection of service procurement are analyzed. These factors have been classified into two groups of metrics: the value of service and the risk of service procurement. Based on the fuzzy soft sets, the model for purchasing selection are established by integrating metrics and comparing the most suitable service value with the risks of service procurement.Second, the evaluation and selection of service providers in the process of service purchase are further investigated. By introducing a variety of vendor selection model into the vendor selection framework, the IVIFSS(Interval Valued Intuitionistic Fuzzy Soft Set) decision model is proposed. The weighted average operator, optimistic decision operator, and pessimistic decision operator for IVIFSS are also presented to solve the problem of comprehensive evaluation of service provider of high risk and low service value. For the case of high service value and high risk of service provider selection, the service providers' selection model are established based on the price and service level agreement. The service value and purchasing risk are further enhanced. The service level agreements are introduced for the qualification of service quality. The TOPSIS(Technique for Order Preference by Similarity to an Ideal Solution) method is ultilized for standarizing various different types of parameters and different values of metrics.Further, the problem of selection can be soloved by the service providers' selection model based on the price and service level agreement between price and main elements of service.Finally, in consideration of the continuous improvement requirements for the efficiency and quality of service procurement, the purchasing selection model is optimized by adjusting the most suitable service value and the value of service procurement risks. The parameter reduction method based on fuzzy soft set are utilized for solving the optimal problems of metrics in selection of service providers. The detailed optimization actions, methods, and procedures in the actual application of enterprise are also discussed.In this dissertation, two kinds of important problems have been studied systematically in the field of enterprise service procurement. A series of models have been proposed for the selection of purchasing patterns and the selection of service providers. These models include the purchasing decision-making model based on the fuzzy soft set, the service provider selection model based on the interval intuitionistic fuzzy soft set, the service provider selection model based on the fuzzy soft set and TOPSIS, and the service procurement optimization model based on the parameter reduction of fuzzy soft set. These models have been applied to the practical applications of enterprises service procurement, including the selection of various planning service purchasing, the promotion of enterprise culture, and the selection of enterprise data center and Internet access service providers.Meanwhile, the proposed models and methods are also extensions of some existing basic problems of management science, such as multi-attribute group decision making theory, comprehensive evaluation method, and feature extraction and selection method. The proposed models and methods include the interval intuitionistic fuzzy soft set model and the relevant weighted average operator, the optimistic decision operator, and the pessimistic decision operator, the two stage TOPSIS decision model, and the parameters reduction of soft sets.