Sharif Digital Repository

Supplier selection is a strategic decision that has a key impact on the success of the supply chain. Due to the nature of goods and storage conditions in the cold supply chain has a great impact on environmental pollution compared to other chains, and it also has the possibility of disrupting the chain due to the importance of temperature and time conditions. Currently, due to the spread of international pressures on the observance of environmental and social principles, the issue of choosing a sustainable supplier has been raised. Also, the expansion of supply chains has caused the challenges and risks faced by supply chains to expand and disrupt the chain, so the decision of supply chain... 

The assumption of infinite lifetime is common in most of the inventory models. However, the perishability of products is a major problem of some industry sectors in which by disregarding the finite lifetime of their products the resulting model may give inaccurate results. Although, significant studies have been carried out for inventory control of perishable products, yet the literature needs more studies to develop or optimize the inventory policies. In this thesis, the inventory control of perishable products is considered. For the case of stochastic demand, it was well known that there is no inventory control policy in which both the order size and the order interval are constant with an... 

Reviewing trends of energy consumption in the world reveals that sooner or later energy resources will be depleted. This concerning rate of consumption has brought about more greenhouse gases (GHG) emission influencing deleteriously on environment and climate. Human has continued energy consumption to maintain and improve the quality of his life through industrial production. Industry as a significant energy user owns considerable contribution to this consumption. Several attempts have been carried out to develop energy management systems in order to improve the energy efficiency of industrial sectors. Whilst they are comprehensive and could be applied to any sector, there is lack of... 

This thesis presents an inventory control system which is based on Meta-heuristic Algorithms.In this thesis we will optimize the input values of our tree-echelon inventory model (keeping costs,stock worth,reorder costs,...) with these Algorithms. The presented method is able to determine the optimal stock level, costs of system and number of shipments in the system. The method is basically a decision support system (DES) and it is able to provide the order scheduling parameters of goods at operational level. The aim of the current research is to demonstrate that a Meta-heuristic algorithmis capable of solving complex inventory problems and with future improvements it is able to achieve... 

The behavior of boundary layer under the effect of the sweep angle is considered. The measurements were performed by a pitot tube rake. Three models with various sweep angels at angles of attack -2, 0 and 2 degree were tested. Both tip and root of all wings were closed by flat plates in order to prevent the flow to roll-up. However the flow field on the wing was still three-dimensional because of the sweep angle. The velocity on the wing has two components; longitudinal and lateral. The cross flow emerges due to the non-equilibrium of pressure and centrifugal forces. The velocity profiles showed that the magnitude of cross flow was stronger near the leading edge of the wing. The cross flow... 

The competitiveness of a port convinced shipping lines and shippers with a significant basis in selecting a port. Port authorities and port operators can make use of the competitive advantage as a parameter for counter measures by grasping the advantages and disadvantages of the ports and be a prime factor of opportunities and threats of the ports. Ports have a significant role in today’s networked business environment. They are being regarded as hubs that are part of various logistic systems. The very essence of a seaport is to link maritime networks and land network. These networks for the port are means of analyzing its competitiveness. A port overall competitiveness is determined by it’s... 

Wireless Sensor Networks have become widespread because of their flexibility, applicability and ability to precept data with high accuracy. However, the most limiting factor in their usage is the amount of available energy in nodes since energy depletion in a node means that it is dead, therefore many efforts have been done for optimum energy management in Wireless Sensor Networks. In many cases, the key solution to prolong the network lifetime is load balancing. In this way, all the nodes will die (approximately) together and the lifetime of network will be maximized. Load balancing can be implemented in all layers from physical layer to application. It should be noted that it is not always... 

Concrete is the second most structural material in the world. So attention and promotion of the concrete mix design with respect to variable issues and requirements, is very important. On the other hand, these days environment and its pollution has become very popular discussion. Waste-glass which is produced by human products is one of the environmental pollutants. In this thesis it replaces some aggregate in concrete and it can reduce the level of this material in the world. Also we study effects of silica-fume as cement replacement and properties enhancer in our concrete mix design and see how it can ... 

In recent decades the use of FRP materials for strengthening structures has been developed extensively, thanks to their high strength, sufficient stiffness, high durablity, and ease of use. A great deal of research has been conducted on strengthening reinforced concrete beams and columns with FRP composites. By contrast, not many researches are performed on slabs, especially two-way slabs. In these few researches, the loading and boundary conditions are limited to simplest ones. Therefore, in this thesis, the focus of attention is on strengthening reinforced concrete slabs under various loads and boundary conditions using FRP composites.
In this thesis, first, FRP composites and their... 

This research attempts to develop the optimal solution for an inventory problem consisting of a single machine which produces items some of which may be defective. We assume that no shortages are allowed and all defective items are to be reworked. Setup cost for rework and waiting time of defectives are considered. This research consists of two different parts. In the first part we consider two different policies where in the first policy in each cycle after the regular production the machine is setup for the rework of defectives of the same cycle. In the second policy several cycles constitute a period. All the defectives produced in the period are reworked in the last cycle of that period.... 

Energy harvesters are used in today’s Wireless Sensor Networks (WSNs) to harvest the energy from the environment. One of the important advantages of the energy harvesting sensor networks over battery-operated sensor networks is that the use of the energy harvester prolongs the life time of the nodes, while a battery-operated node becomes useless once its energy runs out. Although an energy harvester can provide a supply source with a lifetime much greater than a battery, the amount of available energy for an energy harvesting system is a random variable and is not as predictable as the energy of a battery. This unpredictability may cause reliability problems. In order to solve the existing... 

Reinforced concrete (RC) shear walls with a curved cross-section are appealing structural elements to architects and engineers due to the aesthetic and structural advantages. Owing to the paucity of decent experimental research on curved RC shear walls (CRCSWs), the seismic response of these structural elements is essentially unknown. In that regard, this study includes research on a high-demanding type of structural element, which has found its application in North America, Europe, Asia, and to some extent in the Middle East with relatively no design specifications and laboratory research, structural analysis, and design methodology. Therefore, in order to provide an insight into the... 

Dealing with uncertainty in demand, Seasonal product retailers have to make two important decisions. The first one is pricing of the products during their selling season and the second issue is the inventory level and also reordering decisions during the aforementioned period. It is worth mentioning that all products are using a shared capacity which left us barehanded with the pricing and optimizing inventory levels independently. In this thesis, a new model for retailers is presented which includes demand learning and determines optimal prices and inventory policies for multiproduct industries  

In this research, we study the differences between the centralized and decentralized approaches in a two-stage serial supply chain including a manufacturer and a retailer under the lost sale policy. The centralized approach results in optimal solution of the system and the decentralized one is based on Stackelberg game in which the manufacturer is the leader. The retailer uses the continuous review (r, Q) policy and the demand arrives according to the stationary Poisson process. In order to obtain the solution for two approaches, a set of computational steps are developed. Furthermore, we provide a numerical example and the corresponding sensitivity analysis to compare the two approaches.... 

This thesis is related to applying survey of scientific inventory control methods in Khoramshahr Oil Extraction Company (KHOEC). KHOEC is the producer of edible oils in I.R of Iran and is a subset of E.T.K.A holding organization. The inventory costs of high consuming items are studied and optimized based on the optimal ordering policy (r, Q). First, the company raw materials are identified and classified based on ABC analysis method. For developing the new method of inventory control, the demand for each item is predicted, and the probability distribution of demand during the lead time is determined. Then according to this information and the desired service level of management, order point... 

In this thesis, we consider various Make-to-Order systems as a version of integrated production-inventory systems. Most Make-to-order systems can be sufficiently modeled by a queueing system with inventory in which completing each service in the queueing system requires an on-hand inventory. Unlike most researches in this field, we present an analytical approach. In all systems we embed a stochastic process with joint state space that can entirely describe the state of system. Then steady state distributions are derived. Those distributions are applied to compute performance measures and long-run average cost function which can be used for optimization. In our Make-to-Order models, demands... 

Inventory control has been always considered important due to its prominent role in managing and better application of resources in the field of operational systems. Ordering system or review stock policy in supply chain management can be mentioned as one of the inventory control study fields of management. A lot of researches have been done in investigating ordering system in supply chain under certainty conditions; however, since the real world is full of uncertainties, parameters such as demand cannot be predicted exactly and we encounter with ambiguity. In this case, using crisp (exact) values can cause to decide wrongly (a wrong decision). On the other hand, due to absence of sufficient... 

In this paper, we consider a three-echelon supply chain consisting of a producer, a distributor and a retailer. Generally each echelon tends to minimize his own inventory costs. On the other hand, competitive environment of business market, force companies to develop strategic alliances. In order to boost their partnership, separated echelons must integrate their policies, so that the total cost of the system be minimized. The model, extends the research of Wang et al.(2011) by changing the No shortage assumption into backlog shortage model.
This study assumes different deterioration rates among different echelons, and deterioration rates are time-sensitive, which is very helpful in... 

Embedded system Project management , because of lots of unstable parameters in design and also diversity of the technical knowledge ,requires a complex and agile project management methodology. Whereas in these projects , different knowledge fields are applied (such as electronics ,telecommunication ,control and robotics) and software is an evitable part of these systems ,project managers can not be familiar with all aspects of the technical and professional in deep manner. Considering that usually ,the project managers of such projects are elected from professionals of hardware or mechanical sections and not in deep inception of software project management , this thesis focus on a new model...