Sharif Digital Repository

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... 

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... 

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... 

Urban mobility platforms introduced as an innovation in matching suppliers and demanders to each other in the transportation market in recent years. In this research, we applying synthetic control method to analyze the impact of this kind of platforms on labor market variables like work hours, income and number of employed persons in affected activity group. We use the ISIC correspondence tables for versions 3.1 and 4 and also Iran labor force survey and household survey to making activity control groups. The results show that work hours for main work in the related group were reduced. As well as the number of employees in the group increased 100 thousand people and the number of earners... 

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... 

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... 

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 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... 

The role of government in economy has been a controversial subject in economics. Lately, there has been some fundamental change in evaluating this subject. One could mention two of these as 1) realizing the importance of micro-founded macro model for evaluating policy, and 2) taking into consideration the rent-seeking behavior of politicians. In this research, a general equilibrium in a micro-founded macro model will be discussed and then in political economics framework, the effect of government on this equilibrium will be investigated. Only the redistribution role of government has been considered. First, the model in which a benevolent government is seeking optimal policy is Discussed.... 

Due to important applications and benefits of mass transfer in engineering and especially in nano-scales engineering, nano-science researchers have focused on this field. Considerably, in classical fluid dynamics applications, the fluid can be transported using differential pressure gradient. But the classical methods require moving components, which are usually expensive and not applicable in nano-sizes. To avoid these problems in nano-size transportation, we can use electro-osmotic process to perform mass transfer in low transfer rates. In electro-osmotic process, we can move electrolyte solvent with the aid of an external electrical field. Due to importance of this process in... 

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... 

The low female labor force participation rate in the Iranian labor market relative to the global average and even to countries that do not differ significantly from the socio-economic characteristics of our country is one of the important questions of the Iranian labor market. In this study, we seek to answer the question of whether the economic participation rate of married women will increase if the gender gaps in wages, job findings and job losses among women and men are eliminated in the Iranian labor market. To answer this question using household expenditure and income data and labor force data, we show that between the two categories of occupations, in terms of the share of women's... 

In this study, we aim to learn representations from microscopic cell images that effectively capture the features of drugs affecting the cells, allowing us to identify effective drugs for treating a disease. We employ two parallel learning paths using predictive and generative models. Specifically, we have achieved a predictive model on the RxRx19a dataset that, unlike previous models, is interpretable, optimized, and robust to dras- tic changes in drug properties. Additionally, we have developed the first generative model on this dataset, which not only generates high-quality images but also discovers a meaningful latent space. This latent space divides the representation into relevant... 

Co-movement between inflation and nominal interest in response to an interest rate shock, dubbed neo-fisherianism, has been the subject of contentious debate since the advent of non-inflationary ZLB environment. We design an economic model rich with banking features to understand the economic responses to permanent and long-term interest rate shocks. We find that responses to a permanent positive interest rate shock depend on the monetary authorities’ speculation of the new long-term inflation rate, with the most probable outcome being a permanent increase in inflation. Responses to a long-term positive interest rate shock depict an increase and then decrease in inflation. We also discover... 

Fatigue crack growth can have harmful effects on the reliability rotary machine. While an early warning to crack, can be used to extend the life of these expensive machines and increase reliability.Structural Vibration Condition Monitoring as a primary fault detection method, achieved to a lot amazing result and for this reason studies vibration behavior of cracked rotational shaft is a big issue for engineers of dynamic machine.In this research, first check the fault detection methods based on structural vibration condition monitoring, mode shape methods were extracted. Then by modeling rotational shaft in computer and creation of crack on it, fault detection quality of these methods have... 

It is important to provide an appropriate and economically method with technical and engineering considerations to stabilize excavated underground spaces. The necessity of this, especially for the construction of underground metro stations located in the cities which faces many problems, is more evident. In this research, it has been tried to introduce an optimal method according to the type of area for the construction of the underground station. In order to obtain stress and strain condition in structural elements and surface deformations due to different stages of excavating, numerical modeling in FLAC3D has been used. By examining the parameters that affect the sustainability of this...