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Simultaneous planning of project scheduling and material procurement can improve the project execution costs. Hence, the issue considering this approach that each activities requirement can be distributed on the duration of it, has been addressed here by a mixed-integer programming model (named model 2). The proposed model facilitates the procurement decisions by accounting for a number of suppliers offering a distinctive discount formula from which to purchase the required materials. This paper proposed a genetic algorithm combining with a heuristic method to deal with the problem. The underlying factors of the solution methods are calibrated by the Taguchi method to obtain robust... 

In this research a mathematical formulation is presented for project scheduling problem subject to non-renewable perishable resources where the objective is minimize the cost of ordering and maintenance of resources. We use the framework of a resource constrained project scheduling problem (RCPSP) with finish-start precedence relations between activities and resources will be perished after a determined duration and must be procured. Resource procurement have ordering and purchasing costs and excess resources must be stored and have maintenance cost. There is a unique way to perform the activities and preemption is not allowed.
This work employs Genetics Algorithms to solve the problem... 

Among various types of resources defined in the project scheduling literature, the most studies have been conducted on the renewable and nonrenewable resource types. Definition of different resources in the project scheduling literature is based on the specification of the resources in the real projects. Yet there are some sort of nonrenewable resources in the real projects that are not exactly similar to the type defined in the project scheduling literature. The difference stems from this fact that in the project scheduling literature, it is supposed that the nonrenewable resources required for the execution of the project activities are available in full amount at the beginning of the...