An Interval Type-2 Fuzzy Dynamic Approach To Replacement of Server Equipment

Equipment replacement decision which aims to find the best time to retire an old system is a key element in the planning process. Replacement scenarios consider the life span associated to each equipment category and the replacement of the obsolete equipment by an equivalent during the remaining life span after its obsolescence. This multi-stage decision-making problem can be solved by dynamic programming, but technical features that change over the years, unpredictable economy and time can cause uncertainty in prices. By combining classical dynamic programming with fuzzy set theory, this model can be revised. The purpose of this paper is to develop an optimal equipment replacement policy using combined interval type-2 fuzzy set and dynamic programming for the first time. The proposed methodology is applied to server equipment replacement problem.

I. Introduction

The demand for renewal is attribute to factors such as age, worn out, lack of economic sufficiency, or technical inadequacy. In this case, engineers can apply different scenarios such as the use of old machine after maintenance or to purchase a new machine. The basic problem concerns a type of machines which deteriorate with age, and make decision about when to replace the incumbent machine, when to replace its replacement so as to minimize the total cost during the next N years.