Sharif Digital Repository

Hub and Spoke networks come into play when considering direct link between all origins and destinations is either impossible or expensive in a transportation system. In this kind of problems, some nodes are chosen as hub from all origin and destination nodes to collect flows and then distribute them. Implementing hub network leads to minimizing transportation cost, sorting flows and conveying them in economies of scale. Otherwise, shipping flows directly may cause decreasing the travelling distance and the delivery time consequently. In this dissertation, combination of hub network and direct shipment is investigated. To obtain the optimal hub locations and direct links between non-hub nodes... 

In real life, we can not always expect agents and authorities to have the same desires. Also when it comes to conflicts, agents always tend to break the authorities’ norms to follow their own strategies. Hence we can not expect strict norms to model an actual real life situation.In this article we introduce punishment normative systems, based on multi-agent Marokov chain processes (MMDPs). We try to extend the punishment idea to be also applicable on long-run and infinite strategies. We consider a version of the multi-agent model that is widely used in different situations and then provide an algorithm to find a fair normative system that distributes obligations equally on the agents, while... 

This dissertation attempts to develop four inventory control models for two-echelon supply chains. For the all models, the retailers face Poisson demand and lost sales during a stockout. There is also a time-dependent holding cost and a cost per unit of lost sales. However, there is no (or negligible) cost associated with placing an order.
For the first model, we consider a two-echelon inventory system with one central warehouse and a number of retailers. The central warehouse applies (R, Q) policy and retailers apply base stock policy. In this model, we approximate the arrival process of the central warehouse and obtain the total cost of the system, as well as the optimal solution.... 

Production scheduling is such a key issue that directly influences on the performance of the machines and efficiency of production line. This category of problems is to find simultaneously the lot sizes and their sequence over a finite set of planning periods.
In this Thesis a multi objective production planning and job shop scheduling problem is investigated. The objectives are minimization of the production cost and minimization of production time smoothness in consecutive periods. As the problem is shown to be NP-hard, two multi-objectives genetic algorithms with two approaches in selection of parents and crowding distance index are proposed to solve this problem. In these two meta... 

This research deals with a supply chain consisting of one vendor and several retailers. Every retailer orders a fixed discrete quantity in fixed discrete time intervals. Order quantity and order cycle of each retailer could be different from the others. The vendor orders the required quantity to a supplier to fulfill the received demands. Also the vendor orders a discrete quantity, which will be immediately received at the vendor’s warehouse. In this supply chain system, the lead-time is assumed to be zero and shortage is allowed for vendor. The aim is to find minimum vendor’s inventory cost. We proposed a backward Dynamic Programming algorithm for the model. The algorithm creates vendor’s... 

Extensive growth of the internet has had a profound effect on the business environment and rise to a phenomenon known as electronic commerce.electronic commerce has an important role in improvement of organization performance and likewise,has influence in everyday life.despite its name,e commerce is not fully automated.typically,online transactions require a significant level of human intervention.to achieve high degree of automation,we need a new model of software.this model is based upon the notion of agents.agents can act in different stages of e-commerce.one of the most important of these stages is negotiation.negotiation capabilities are essential for e-commerce systems.the agents... 

Agent-Oriented Software Engineering is one of the novel and growing paradigms in computer science, which provides systematic approaches for analysis, designing, implementation and maintenance of multi-agent systems. Agents are the main entities of the agent-oriented software systems. Agents are autonomous and behave flexibly and intelligently. This paradigm is appropriate for developing open, complex, flexible and distributed systems. Design pattern is a general reusable solution to a commonly occurring problem within a specific context in software design. Using patterns in software design has many benefits such as increasing the quality and robustness of the software. Regarding the fact...