network marketing phenomenon in which mendacious mediators are eliminated, basically is a useful matter. but the companies so-called pyramidal schemes misuse this title. in this companies there isn’t any production, consumable goods and useful work and they just constitute the pyramids in which the money belongs to persons in lower level go into the pocket of company and few people who are in t...

in this article, multiple-product pvrp with pickup and delivery that is used widely in goods distribution or other service companies, especially by railways, was introduced. a mathematical formulation was provided for this problem. each product had a set of vehicles which could carry the product and pickup and delivery could simultaneously occur. to solve the problem, two meta-heuristic methods...

The performance of a product is often evaluated by several quality characteristics.  ptimizing the manufacturing process with respect to only one quality characteristic will not always lead to the optimum values for other characteristics. Hence, it would be desirable to improve the overall quality of a product by improving quality characteristics, which are considered to be important. The probl...

In the petroleum supply chain, oil refined products are often delivered to distribution centers by pipelines since they provide the most reliable and economical mode of transportation over large distances. This paper addresses the optimal scheduling of a complex pipeline network with multiple branching lines. The main challenge is to find the optimal sequence and time of product injections/deli...

  This article investigates integrated production-inventory models with backorder. A single supplier and a single buyer are considered and shortage as backorder is allowed for the buyer. The proposed models determine optimal order quantity, optimal backorder quantity and optimal number of deliveries on the joint total cost for both buyer and supplier. Two cases are discussed: single-setup-singl...