b a c k g r o u n d & aim: multi-state models can help better understand the process of chronic diseases such as cancers.  these models  are influenced  by assumptions  like individual  homogeneity.  this study aimed to investigate the effect of lack of individual homogeneity  assumption  in multi-state models. methods & materials: to investigate the effect of lack of individual homogeneity ass...

strategic selection problem is a multi-criteria problem which includes conflicting tangible and intangible criteria. in order to select the most appropriate strategic alternative it is necessary to make tradeoffs between these criteria as well as taking into account the resource limitations which may exist. available methods neglect the distance concept which exists between the alternatives wei...

This paper proposes a comprehensive, multi-objective, mixed-integer, nonlinear programming (MINLP) model for a cell formation problem (CFP) under fuzzy and dynamic conditions aiming at: (1) minimizing the total cost which consists of the costs of intercellular movements and subcontracting parts as well as the cost of purchasing, operation, maintenance and reconfiguration of machines, (2) maximi...

this research provides an optimization tool for use by supply chain managers in the design and operation of manufacturing- distribution networks under uncertain demand conditions. the problem under consideration consists of determining the supply chain infrastructure; raw material purchases, shipments, and inventories; and finished product production quantities, inventories, and shipments neede...

Reliable location routing problem considers a location problem and a vehicle routing problem in order to select the optimal location of facilities and at the same time the optimal routes for vehicles considering the unexpected failure for facilities in which, all facilities may fail with a probability. In this paper, a bi-objective mathematical model has been developed to minimize the total cos...

The transportation hassle, in operations research, is perhaps one of the issues that studied more. There exists a plenty number fashions to resolve hassle simply product, which does not take place now like identical case multiples products. had been where assimilating multiple product single product. research has focused proper exposition trouble couple transport, and simplest cautioned some te...

Determining supplier and optimum order of the quantity is an issue of great importance in logistics management for many companies. In this regard, it is crucial to determine the best decisions for the order quantity as well as the most suitable supplier through considering existing limitations and uncertainties. To optimize a multi-product, multi-period model with select supplier for deteriorat...

  In this paper, different input-oriented ratio-based DEA (DEA-R-I) models are proposed. By presenting the envelopment-additive-enhanced Russell model based on the DEA-R-I form, each decision making unit is evaluated and its efficiency score is calculated. Also, by presenting the central resource allocation model based on the DEA-R-I form, a suitable benchmark for all DMUs is proposed by solvin...