This paper studies an alternating renewal process when on-off times are random fuzzy variables. We provide a theorem concerning the long-term average expected service times of customers. Here, we do not use the α0-pessimistic value and the α0-optimistic value of fuzzy variables, we simulate the expected value of random fuzzy variables based on fuzzy simulation to calculate the long-term average...

In fuzzy decision systems, we model insuring critical path problem by two-stage risk-aversion fuzzy programming. For the proposed two-stage insuring critical path problem, we first define three solution concepts, expected value solution, wait-and-see solution and here-and-now solution, then introduce the value of perfect information of value-at-risk (VaRVPI) and the value of the fuzzy solution ...

In this paper, we construct fuzzy renewal processes involving fuzzy random variables. We first extend the renewal processes to the fuzzy renewal processes where interarrival times, rewards, and stopping times are all fuzzy random variables. According to these fuzzy renewal processes, we then extend some theorems of renewal processes to those in fuzzy renewal processes. These are elementary rene...

In a stochastic and fuzzy environment, two kinds of stopping models are discussed and compared. The optimal fuzzy stopping times are given under the assumptions of monotonicity and regularity for stopping rules. Also, we find that fuzzy stopping times are favored in a comparison between fuzzy and classical stopping models. Q 2000 Academic Press

In a continuous-time fuzzy stochastic system, a stopping model with fuzzy stopping times is presented. The optimal fuzzy stopping times are given under an assumption of regularity for stopping rules. Also, the optimal fuzzy reward is characterized as a unique solution of an optimality equation under a differentiability condition. An example in the Markov models is discussed.

This paper deals with the problem of optimization of job sequence in a two-machine flow shop problem in the presence of uncertainty. It is assumed that the processing times of jobs on the machines are described by triangular fuzzy sets. A new optimization algorithm based on Johnson’s algorithm for deterministic processing times and on an improvement of McCahon & Lee’s algorithm is developed and...

Optimizing jobshop-scheduling problems (JSSPs), in wh ich imprecise processing times are modeled as fuzzy numbers, results in more flexible solution. That is, the produced schedule is flexible; it stays valid and can cope with all possible durations within the specified range. In this paper, we present evidences that support the claim that solving JSSPs with fuzzy processing times would produce...

h a stochastic and fuzzy environment, a multiobjective fuzzy stopping problem is discussed. The randomness and fuzziness are evaluated by probabilistic expectations and linear ranking functions, respectively. Pareto optimal fuzzy stopping times are given under the assumption of regularity for stopping rules, by using X-optimal stopping times. @ 2003 Elsevier Ltd. All rights reserved. &Fords-Mul...