Street-lighting lamps replacement: A fuzzy viewpoint

Campbell's statement on a street-lighting system is expressed as that N street-lighting posts have to be provided continually with lamps. In this paper this statement is fuzzified such that the system failure is defined in a fuzzy way. Then a concept of fuzzy reliability is introduced in the context of the transition from the system fuzzy success state to the system fuzzy failure state, where a transition between two fuzzy states is just a fuzzy event. With the concept of fuzzy reliability we make a comparison between two replacement policies, viz. the block replacement policy in a non-fuzzy environment and the periodic relacement policy without repair at lamp failures in a fuzzy environment, and comclude that a complex system may be as reliable as a simple one in view of the system fuzzy reliability.