A fuzzy queuing coherent hierarchical location-allocation model is developed for congested systems. The parameters of the model are approximately evaluated and stated as fuzzy-numbers. The coverage of demand nodes is also considered in an approximate manner and is stated by the degree of membership. Using the queuing theory and fuzzy conditions, a coherent hierarchical model is developed for th...

A fuzzy inventory model with price dependent demand is considered. The shortages are allowed . The objective is to determine the optimal total cost and the optimal time length of the plan for the proposed model. The trapezoidal fuzzy numbers are introduced to achieve this objective. The signed distance method is used for defuzzification process. To illustrate the results of this model, sensitiv...

Considering the vehicle routing problem with fuzzy demand and time windows, a optimization method is proposed considering both soft windows uncertain customer demand. First, chance-constrained programming model established based on credibility theory, minimizing total logistics cost. At same time, random simulation algorithm designed to calculate penalty cost of delivery failures caused by that...

disasters can cause many casualties and considerable destruction mainly because of ineffective preventive measures, incomplete preparedness, and weak relief logistics systems. after catastrophic events happen, quick and effective response is of great importance, so as to having an efficient logistic plan for distributing needed relief commodities efficiently and fairly among affected people. in...

The objective of this paper is to develop an inventory model with fuzzy inflation and multi variant demand rate. A new demand rate introduced which depends on price, quality and time. Planning horizon is random in nature for manufacturing company. Production rate is taken to be flexible in nature which depends on the technology frequency, capital investment and its elasticity and number of labo...

In this paper, we proposed and trained a fuzzy neural network system to estimate future logistics demand. The structure of neural network in the system is similar to that of BP network, except that here the nonlinear sigmoid functions in the networks are replaced by fuzzy reasoning process and wavelet functions respectively. Moreover, the trained network system is put into practical logistics d...

A three-level relief chain including a number of suppliers in fixed locations, candidate distribution centers and affected areas at certain points are considered. A mixed integer nonlinear programming model is proposed for open transportation location routing problem by considering split delivery of demand. To solve a realistic problem, foregoing parameters are considered as fuzzy in our propos...

Utilization of water in different parts of industrial life cycles brings a huge concern on environmental water and wastewater pollutions. In this research, environmental quality assessment of wastewater is studied using fuzzy logic. Fuzzy appliance is due to existance of statistical considerations (including standard deviations), various uncertainties, non-linearity and complexity of functions....