Sharif Digital Repository

The existing statistical studies implies that in Iran like most of developing countries, the great percent of houses are traditional. Statistics of the most disastrous current quakes also show damages caused by masonry structures in developing countries. The main problem of brick and masonry structures especially the unreinforced one is their weak performance against quake. Different methods are use to analyse the seismic performance of this structures. The modern endurance time method is a kind of time history analysis using standard increasing accelerograms which examines different parameters of structure behavior during excitation actions. In this project we analyse these structures using... 

Every year, air pollution is causing immense harm to humans and the environment. To cause Air pollution, several factors are involved. Among these are the sources of emissions such as factories, power plants and Cars, meteorological factors such as temperature and wind speed and geographical conditions such as altitude, postal and looming around the area, land slope and soil type region. The aim of this study is to identify factors that affect the ozone concentration in Tehran, which could help identifying other secondary pollutants. For this purpose, a combination tailored to the geography of Tehran using CMAQ-WRF-SMOKE-made programs. This model includes four intervals each of which lasting... 

Export subsidy is one of the important issues among the various trade policies in developing countries. For more than a century, various effects of export subsidies have been studied in literature and different results have been presented. In this study, the effect of export subsidy of several agricultural products on their weight and export price has been investigated. In 2015 and 2016, respectively, potatoes and five groups of dairy products were subject to cash subsidies. The results of the research show that the growth of potato’s weight has been affected by the subsidy and has increased. Also, according to the results, the effects of the decrease in export price growth can be seen, and... 

Resin Transfer Molding (RTM) which is one of the categories of Liquid Composite Molding (LCM) process, is considered as one of the most important process in polymer composite manufacturing. To improve this manufacturing method and reaching higher qualities, numerous modified methods has been developed. One of these modified methods is Vaccum Assisted Resin Trasnfer Molding with Flexible Tooling which is considerably applicable in manufacturing parts with high quality, large and complex geometry. Although, this manufacturing method has variety of advantages, there are some problems such as void formation making production difficult and dependent to experimental trial and error. So numerical... 

Solid-State Disks (SSDs) offer advantages such as no mechanical parts, low power consumption, and constant read latency. SSDs, however, suffer from shortcomings such as erase-before-update requirement and limited endurance.Redundant Array of Independent Disks (RAID) are commonly used in storage servers to enhance performance and reliability. To further enhance system performance, one can employ efficient Input/Output (I/O) scheduling algorithms suitedto the disk structure in RAID-based systems.In this thesis, we present an I/O scheduling method to improve endurance and performance of SSD-based RAID systems. In the proposed I/O scheduling algorithm, read requests are sent directly to SSDs and... 

The increasing demand for air transportation, along with air traffic limitations and environmental pollution concerns, necessitate a comprehensive study in the field of airspace-management. In this regard, one of the promising alternatives is flying smarter via “Formations”. In fact, many works have discussed the benefits of “Commercial Formation Flights”; however, none have discussed a practical way to manage such formations for long-distance cruise. This paper discusses a new approach to manage the “Geometrical Arrangement” of such flights in an efficient manner. In fact, with the help of the so called “Game Theory” and without complex computations we are able to guide each individual... 

Mixed-critical systems (MCSs) use a common hardware platform to schedule and execute tasks with multiple critical levels. Multi-core processors are commonly used by these systems, and batteries are frequently employed to provide the energy they require due to their portable nature or lack of access to large energy sources. Therefore, it is essential to use energy-management methods, such as dynamic voltage and frequency scaling (DVFS) and dynamic power management (DPM), to reduce their energy consumption. Using power/energy management methods can lead to missed deadlines due to increased execution time of tasks. In two-level mixed-critical systems, the lack of correct and timely execution of... 

Nowadays more than half of the world’s population lived in urban areas. That proportion is set to rise to 67% by 2050. This will cause urban mobility with serious problems. The concept of Urban Air Mobility (UAM) is proposed to avoid the problem to become a catastrophy. Due to environmental issues and also high operating costs, using copters as an air-taxi was not justifiable. As the technology in e-VTOL flourished, the desire of using of these vehicles in such a transportation system was increased. In this paper, besides previous investigations, the e-VTOL’s performance parameters’ influence on the characteristic of a civil air-taxi network is under investigation. In addition, this paper... 

The use of electric vehicles is increasing day by day due to the reduction of pollution, reduction of fuel costs, higher efficiency, etc. Increasing the distance traveled in each charging period of the electric vehicle battery pack and increasing the lifetime of the battery cells are the most important challenges facing the electric vehicle industry. In electric vehicles, Li-Ion battery cells are used to store energy, so to improve these challenges, we first need to carefully examine the behavior of these cells with the various conditions that occur during operation to design other circuits such as balancing circuits, Battery management system, etc. In this thesis, first a model is proposed... 

Producer-level data for Iranian manufacturing firms shows a large amount of dispersion and concentration in producer level sectoral shares, as well as a very strong relashionship between sectoral shares and markups. We Study the pro-competitive gain from trade in the Iran’s manufacturing sector. Domestic firms in Iranian manufacturing sector are protected via tarfiff and non-tariff barriers enforced by the government. In many sections of manufacturing sector, domestic firms feel little competition and charge high markups. The market power of domestic firms could be reduced by the reduction of tariff rate and increase in import share. As a result of foreign competition pressure, they would be... 

The primary purpose of the present research is development and implementation of advanced state estimation and control techniques for space rendezvous and docking. To achieve this aim, the present study has first investigated the use of graph neural networks (GNNs) to filter out the noise of the sensor data in the state estimation process. The measurement package is consisted of a gyroscope, star trackers, and a GPS sensor providing inputs to the GNNs. The obtained results showed that the use of GNNs significantly improves the accuracy of the state estimation compared to traditional methods. In addition, the study has focused on developing advanced control techniques for spacecraft position... 

Retail stores are one of the members of each supply chain which connect end customers to the other parts of supply chain. Matching customers demand with product supply, is one of the most important duties of retail stores. There are a big variety of products in retail stores and also many new products continuously enter to the stores, in the other hand available spaces for displaying products are limited and keeping those products in the shelves and warehouses will cost. However the amount and location of displaying products in shelves, directly effect on customer demands. When deciding about shelf space allocation, all of these issues should be considered. In addition, inventory control is... 

If nuclear radiation is not weakened and absorbed, it can cause serious damage to human devices or the environment. Dual-purpose dry casks are one of the sources of nuclear radiation production as a place to keep the spent fuel assemblies. One of the ways to protect against them is to use shield. One of the most common of them is composite shield. The composite used in this study has a polymer matrix. The matrix of the used polymer is epoxy resin. In this study, two separate composites have been made to attenuate neutron and gamma radiation. In this thesis, first, by using the MCNPX code, the necessary simulations for the design and construction of composite shields have been carried out.... 

In this study, epoxy resin has been modified by nano-clay additives using direct mixing method and epoxy-clay nanocomposites were designed and produced with optimized percentage of clay content. By adding the powder of born carbide and lead oxide in nanocomposites new compounds are obtained. The results are used for protection against neutron and gamma rays, respectively. After preparation of epoxy-clay-born carbide and epoxy- clay-lead oxide nanocomposite the effects of irradiation and carbon fiber on mechanical and thermal properties of nanocomposites were examined. The Nanocomposites were exposed to Electron Beam Irradiation (EBI) in 100 and 500 kGy doses to investigate the effect of... 

Heart disease is one of the major causes of death in all countries, especially developing countries. At the moment, using Image Processing methods as well as analysis of electrocardiographic signals, heart disease is diagnosed with the help of specialists. Applying artificial intelligence and machine learning methods, many studies attempted to provide models that are used to diagnose automatically the heart disease without the need for a specialist and only relying on the past data. But less is done on CTA images of the heart. Hence, in this thesis, a new method for image processing and a Multi Support Vector Machine (MSVM) classification for coronary artery disease detection based on CTA... 

Statistical studies indicate the fact that in Iran, like many other developing countries, a significant percentage of buildings are made of traditional materials and most of them are adobe buildings especially in rural areas. Furthermore, geological data indicates that Iran is located in alps-Himalayas seismic zone and exposed by destructive earthquakes and adobe buildings suffer the most damages comparing with other type of the structures. According to these explanations, this research deals with adobe buildings behavior and provides solutions for reinforcing them and improving the seismic response of these buildings. These studies include numerical modeling with finite elements methods by...