this paper is a research on the ordering planning of a supply chain with one supplier, multi buyer and multi deteriorating items. items have fixed life time and expire dates. the ordering period is taken as variable and must be computed the proposed models. the problem is studied via two different approaches the first is the joint replenishment, based on the hwang and chew's model [3] and ...

To save overhead and penalty costs, in many cases of Multi-Period Multi-Product (MPMP) planning systems, reducing the completion time is highly desirable. Therefore, in this paper we study this problem. We propose an approach in which a MPMP problem is converted into a project management network. Then, considering network concepts and properties, a multi stage novel mathematical model is propos...

in this paper, a multi-period and multi-resource operating room (or) scheduling and rescheduling problem with elective and semi-elective (semi-urgent) patients is addressed. a scheduling-rescheduling framework based on the so-called rolling horizon approach is proposed to solve the problem. the core of the proposed framework is a novel proposed mixed-integer linear programming (milp) model with...

Model building is a fragile and complex process especially in the context of real cases. Each real case problem has its own characteristics with new concepts and conditions. A correct model should have some essential characteristics such as: being compatible with real conditions, being of sufficient accuracy, being logically traceable and etc. This paper discusses how to build an efficient mode...

in the recent decade, special attention is paid to reverse logistic due to economic benefits of recovery and recycling of used products as well as environmental legislation and social concerns. on the other hand، many researches claim that separately and sequential planning of forward and reverse logistic causes sub-optimality. effective transport activities are also one of the most important c...

Environmental pollution and rapid depletion are among the chief concerns about fossil fuels such as oil, gas, and coal. Renewable energy sources do not suffer from such limitations and are considered the best choice to replace fossil fuels. The present study develops a mathematical model for optimal allocation of regional renewable energy to meet a country-wide demand and its other essential as...