Sharif Digital Repository

It has always been a challenge for retailers to plan which of the available goods will be displayed to the customer and at what price for each. In practice, the limited storage capacity of goods, the limited capacity of shelves, or the limited capacity of displaying goods on a web page in online stores may make it more difficult to decide on the above issues. These issues have been addressed in the literature when demand for goods is clear or a good estimate of demand can be obtained based on sales data. The purpose of this study is to investigate multi period Assortment planning, pricing and inventory planning with respect to the limited capacity of storage and display of goods in a... 

Nowadays, electrical energy is one of the crucial requirements in human beings’ lives. Since the majority of the world’s energy is met by fossil fuel, the problems such as global warming, the reduction of fossil fuel resources, and unpredictable oscillation of the prices of such fuels have led to a serious crisis for the people of the world. Furthermore, due to the increasing energy demand, the economic development of most countries has a strong correlation with fossil fuel prices. The abovementioned problems have made a lot of countries take alternative policies in terms of generating energy, one of which is using renewable energy resources. This approach is reported to be clean and... 

Today, e-commerce systems are used by both types of users. Therefore, the systems will be exposed to systematic fraud, and fraud is one of the main sources of financial losses for organizations. Therefore, it is very important for organizations to use accurate methods to detect fraud. this field is one of the most important applications of data mining in finance. There are various challenges in fraud detection projects, and this research has divided these challenges into three categories, which are: data pre-processing due to the imbalance data set, the accuracy of the machine learning model, and uncertainty. In the first part, both oversampling and undersampling methods will be used in... 

This research examines the importance and implementation of incident management and problem management processes in the field of software development systems. In the fast-paced and dynamic world of software development, incidents and problems can arise that disrupt system performance and impact customer satisfaction. Incident management provides a structured approach to quickly identify, prioritize, and resolve unexpected events, while problem management focuses on identifying root causes and preventing the recurrence of incidents. By addressing the key stages of these processes and their benefits, the research emphasizes the importance of proactive incident resolution, software quality... 

Successfully bonding nickel-base alloys to titanium-base alloys has proven to be one of the most challenging modern joints. Traditional welding methods for dissimilar titanium/nickel joints often lead to cracking in the fusion and heat-affected(HAZ)zones; due to the formation of brittle intermetallic compounds with low fracture toughnesses. Additionally, the significant difference in thermal expansion coefficients between titanium and nickel introduces significant thermal stress during bonding process, exacerbating the current issue. Creating successful dissimilar Ti/Ni joints requires overcoming the formation of continuous brittle intermetallic compounds (IMCs). Brazing stands out as a... 

The classical economic batch quantity (EBQ) model assumes that all produced items have a perfect quality. But in real-life production systems, generation of defective items is inevitable. A portion of these defective items is considered to be scrap , while the other is assumed to be reworkable and reworking them can reduce costs and increase productivity. In this thesis we have studied the economic batch quantity for a single stage production system with rework and scrapping . We want to satisfy the customer demand and minimize total costs of the system like set up costs , production costs , rework costs , holding costs , shortage costs and scrapping costs . In the first chapter of this... 

Nowadays best using of fossil fuels sources of the country (and) importance of comparison against lack of capacity in petrol production make determined the programmers and the directors to foresee and design expanded programs of the goals, to use natural gas for car fuels. To reach fulfillment of these programs, the confirmed needs of the natural gas cylinders are improved and make it essential to invest on producing compressive natural gas cylinders. In this way economical and technical change researches has been done in order to construct on department to produce 200,000 compressive natural gas cylinders in a year during two sets.(shifts) According to the results of technical researches... 

Based on the latest statistical figures, more than 50 billion Rials worth of medical equipment exists in Iran’s medical centers. In spite of this, Breakdown maintenance is used in all hospitals, which means that the equipment is utilized as long as it is not out of order and only in such a situation, i.e. a breakdown, the necessary repair operation is conducted on the equipment. In fact, no maintenance is carried out to prevent a breakdown, while the “prevention from breakdown” concept has long been introduced in the majority of industries in many countries including Iran and its positive impacts are undisputable. This thesis aims at proposing a solution for the implementation of a “planned... 

EOQ and EPQ models have been among the most important and commonly used techniques for about 100 and 60 years respectively .But, they are involved in some assumptions that sometimes prevent them from being implemented in real situation of industry and production. One of these unrealistic assumptions is that all of items received or produced are of perfect quality. In order to overcome this constraint and make the mentioned models closer to the real environmentsome researches have been done. To this end,following the previous attemptsin this project we assumed to have destructive inspections and existence of imperfect and rejected items after rework. In our models, considering 3 circumstances... 

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... 

Queuing systems and their optimization have always been an important concern of every society. It has been a long time that people understand that with quantifying the queues they are standing on, they can save great amount of money and time. Because of that fact, they have been studying these systems, and reached to the interesting conclusions. These researches have shown that there exist a couple of equilibriums in every queuing system, such as: speed-price and speed-quality equilibriums.Knowing these equilibriums along with modeling them will help us optimize queues. The importance of this optimization is its incredible effect on cost reduction in economical and social queues. In many... 

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... 

Price and warranty are two powerful marketing tool that can stimulate consumers’ purchase willingness. Therefore, producers must choose the appropriate price and warranty that can stimulate customers to purchase the quantity that will achieve the maximum profit. This study investigates optimal strategies for price and warranty length of a new product to maximize profit of a producer during lifecycle of the product. We consider both durable products and non-durable ones. Customers buy non-durable products many times but if we consider the planning horizon relatively short, each customer buys one product during the period. So, the market for non-durable products is static and for durable ones... 

When demand for a product is price sensitive, pricing and lot sizing decisions are interdependent. Similarly, when a product is highly perishable, the demand may need to be backlogged to avoid costs due to deterioration, i.e., perishability and backlogging are complementary conditions.In this thesis we stablish two economic production quantity models for deteriorating items under conditions of finite production, exponential decay and partial backordering and lost sale. Two joint pricing inventory control models are developed for the problem by employing different modeling approaches over an infinite planning horizon. In two models, customer is viewed to be impatient and the fraction of the... 

Today, many organizations and companies are confronted with enormous competition and uncertainty as a result of factors such as political issues, demand fluctuations, technological change, and financial instability As well as increasing business competitiveness, organizations focus on their core activities and lead to the use of outsourcing strategies, These factors are the cause of the formation of the supply chain And the lack of planning and identifying the factors that cause instability in the supply chain leads to its inaccurate performance. World-class organizations today have found that unintegrated production and distribution processes and poor communication with suppliers and...