Sharif Digital Repository

The goal of this research is to study the effective factors in order to overcome resistance to change. In today’s competitive world, change is the most critical competitive advantage of an organization to adapt to new circumstances. The failure rate of change projets is more than 70% and there are various factors responsible for this high rate. One of the most important factors is resistance to change. In this research, traditional studies of change starting in the 19’s by Kurt Lewin is the strat point, who had initiated the studies of this field with his three-step model. In recent decades, newer models have emerged which in contrast with previous versions, focused on an individual as the... 

To coordinate between different echelons in supply chains, it is necessary to analyze the multi-echelon inventory systems. Access to advanced technologies in Information Technology make some changes in the inventory management in these systems. Theses technologies that were gradually got inexpensive are attractive for researchers of the multi-echelon inventory systems. Using theses technologies, the information that leads to costs reduction in a supply chain is accessible economically. In this thesis, first efficient solutions for Base Stock and Reorder point, Quantity of order policies will be derived. Then, a serial two-level supply chain comprised of one retailer and one supplier will be... 

Social media can be helpful to people in vast areas, especially in queuing systems, in the real world there is remarkably unknown information like service time, average waiting time or average queue length to customers, thus people are likely to share their experiences to posterior customers who want to use the same service. This research examines the impact of user-generated reviews, on the performances of a Markovian queuing system, we assumed that customers are not aware of the service rate, therefore they will assist next customers by writing reviews about their service time they had experienced. We intend to examine the impact of information on queueing performance such as system... 

In this study we consider a two-level supply chain, with a supplier and a number of identical retailers, demand process is Poisson with random rate. All retailers apply (R,Q) policy with backorder case for their inventory control supplier fulfills the orders of retailers according to FIFO discipline. At any point of time the supplier has online information about inventory position of all retailers.
Whenever the inventory position of a retailer reaches to a fixed value (s) above its reorder point, the supplier orders a batch of size Q to an outside source with infinite capacity. Lead-time of each retailer is equal to the sum of a constant transportation time and a delay time which is... 

In this thesis, we develop seven integrated production-inventory models for two or three-stage supply chains under stochastic and/or dependent parameters. The problem is called Joint Economic Lot Sizing (JELS) and can be considered as the building block for wider supply chain systems. The first and the second researches deal with the problem in which the supply lead time between the vendor and the buyer is stochastic with uniform and exponential distribution, respectively. The numerical analyses shows that the cooperation between two partners is more critical in unpredictable purchasing environments in terms of stochastic lead-times. In the third research, we investigate four sourcing models...