Sharif Digital Repository

In today’s competitive world, using an efficient forecast method is necessity for companies. To now, many forecast methods have been developed, but many of them have not an expected efficiency. In this research, we develop a new hybrid forecast method with application of forecasting retails demand. The hybrid method is the combination of ARIMA method and neural networks. To test the efficiency of the method we use the 96 weeks data of plastic containers demand. We also comprise the hybrid method with other forecast methods including naïve method, ARIMA method and neural network method by applying root mean square error and mean absolute percentage error indexes. In the case of plastic... 

In this research, the synthesis of the electrospum nano fiber doped zinc oxide and its photocatalyst usage was investigated. The band gap of the zinc oxide in the area of UV leads to deactivation of this material at the visible light. With due the attention to sunny weather in Iran and the fact that about 50 percentage of sunlight is visible light, producing and usage of catalyst materials actived at visible light is economical. Doping is one of the ways of activating ZnO at visible light, so in this research thiourea is used as the source of ZnO doping. The results of the expriments done at visible light and also spectrums of DRS, XPS and XRD prove that the doping is happened. Also, in this... 

The objective of this research is to design a drug delivery system that allows anti-inflammatory drugs to be injected directly into the joint (intra-articular injection) for the treatment of arthritis so that reduce the side effects associated with oral consumption of these drugs, increase the duration of drug retention in the joint environment, and reduce the side effects caused by repeated injections while improving effectiveness. To achieve this, first, desirable features were determined by considering the anatomy of the joint environment, the biological changes caused by the disease, and reviewing published articles and commercial products in the field; appropriate drug and raw materials... 

For application such as electrical contacts and spot welding electrodes, both high electrical conductivity and wear resistance are required. Additionally, such parts should have structural stability at evaluated temperature. Copper based composites containing carbides or oxides reinforcement can be the good choice for production of such parts. In present work, in-situ Cu/NbC composite via mechanical alloying with homogenous distribution of nano reinforcement particle has been produced. For this purpose, in first stage, copper powder was milled with 5, 8, 10 and 12 wt. % of niobium powder in two types of mills, i. e. vibratory dicky mill and planetary ball mill for 5 and 32 h respectively. At... 

One of the most important reasons of death in today’s world is the diseases related to cardiovascular system. Hypercholesterolemia is one of the most common forms of these diseases. There are a lot of experiments for diagnosing this disease, which are classified into two groups: invasive and noninvasive experiments. One of the well-known noninvasive experiments in this area is the photoplethysmography in which the changes of the photoplethysmography signal can reveal some valuable information about the cardiovascular system’s health.The objective of this study is to simulate the photoplethysmography experiment considering the clinical conditions of the experiment. In this work, the obtained... 

Policies affect supply chain management in oil, gas and petrochemical industries. In this study, structural equation modeling was used to evaluate the relationship between variables in AMOS software. The findings also indicated that international policies affect different aspects of supply chain management in the following order: product realization management (coordination), customer delivery management (partnership), planning management (planning) and resource management (implementation). Finally, suggestions were made on how to find financing such as bank loans, prioritizing payments in the light of their criticality, as well as on the creation. This study aimed to investigate the impact... 

Government intervention in markets may go beyond the market regulation. Interventions may cause some idiosyncratic price distortions. It means the relative prices of factors to become different among firms. Therefore, micro conditions for firms will be changed. These will result in misallocation of factor production between firms and change in manufacturing TFP. According to data from about 14000 medium and small industrial firms in Iran, removing misallocation of production factors (capital and energy) and output idiosyncratic distortions between industrial firms would result in 115 percent increase in manufacturing TFP.

 

The purpose of this research is the extraction of socio-economic factors (separation of household and household members) that affect the use of banking services in urban area of Iran. In this study we used data of the "family access to financial services in urban areas of Iran in 1387" that has been sampled by the department of economic statistics of central bank of Iran. The statistical information of this organization is in form of completed questionnaires and based on household addresses in a city and contains of 6055 urban household's information. In this project 15922 persons have been studied in urban households include the caretaker and the other family members. In addition to... 

Due date assignment for customer orders has been studied in various production environments. In this thesis a production system is considered in which the orders of several customers are produced in a single lot because of the economy of scale. If a lot is completed before receiving customer orders, inventory carrying cost is incurred. On shortages, a due date is quoted to customers and lead time quotation cost is incurred. The due date may not be met because of (lead-time) uncertainty in production system. Hence if the order is delivered after its due date, tardiness cost is charged. The literature reviews show that such a model is not considered by other researchers. Two different problems... 

A hierarchical production system in make-to-order environment is presented in this thesis. This production system is consisted of three different decision making levels. Maximum acceptance for production within customer specified time interval was done in the first stage, which is called order arriving stage, based on different client criteria, type of demanded product, and production system constraints. A new hierarchical decision making structure for accepting or rejecting arriving orders is proposed in this level. The output of this acceptance level is orders having maximum production system defined criteria, and minimum production cost along with order delivery time with minimum delay is... 

The study on the propane dehydrogenation process has been receiving significant attention due to the growing demand for propylene. The aim of this research is to develop an appropriate kinetic mechanism for dehydrogenation of propane over an industrial Pt–Sn/γ-Al2O3 catalyst in the presence of a very small amount of water. The reaction is carried out over the temperature range of 575 – 620 º C at atmospheric pressure. The results showed that a small amount of water and methanol can improve the performance of catalyst and also, increase the selectivity to COx. Addition the 0.5, 0.45, 0.3 water and 0.1, 0.05, 0.02 methanol are the optimum amount of these oxygenated compounds in order at... 

In recent years in assembly line balancing area many researchers have focused on identifying and modeling real world situations in assembly lines in order to obtain more suitable model. As a result many generalized models have been developed in assembly line balancing area. However, designing efficient algorithms to solve these generalized problems has just begun. In this study it is aimed to design efficient algorithms to solve one of these generalized problems. Specificcally two hybrid genetic algorithms (GA) are proposed to solve assembly line balancing problem with sequence dependent setup times. Scheduling of tasks in the stations has been less considered in the literature of assembly... 

In this thesis, a multi-stage project portfolio selection and scheduling problem in an uncertain environment is modeled, analyzed and solved. Moreover, we investigate the situations in which a project manager is confronted to a large number of projects to be selected and scheduled while the required resources of the projects are limited and renewable. The aim is to maximize objective function which is the net present value of the profit of the projects. To solve the mentioned problem, we introduce a multi-stage stochastic programming. For the reason that, in real problems, optimization problems that included all restraints are large scale and have computational complexity, these problems are...