Sharif Digital Repository

One of the frequent aspects of lawlessness at signalized intersections, is red-light violation (RLV). In addition to its adverse effect on intersection safety, RLV can cause delay in the startup of the vehicles in the next phase defined as “green flow”. In this research, in order to investigate the adverse effect of RLV, the required data were collected from two signalized intersections in the City of Esfahan, Iran using recording cameras. Then, using a cellular network in the intersections and the Aimsun traffic simulation software, the effects of RLV on the delay, capacity, and level of service of the intersections were evaluated. The results show that the behavior of the drivers in the... 

Magnetic levitation is an appropriate solution for noncontact 3D manipulation. Workspace of the previously proposed maglev systems is confined to a relatively small cube, which severely limits the application of this technology. In addition, most of the previously given mechanisms require the design and application of a subsystem in order to unify their magnetic field. In this paper, a moving magnet is proposed which results in a horizontally extendable workspace; moreover, the field unifying section is not needed since one electromagnet only is used. Further, details of the mechanism and finite element based design procedure of the magnet are presented. Dynamic equations of the system... 

Decoherence is one of the candidates for solving the measurement problem, and is among the group of theories which are trying to solve the measurement problem within the quantum theory, by removing the wave function reduction axiom. The main idea is to consider the environment of the system which was ignored in the classical physics. The openness of a quantum systems makes the system and its environment entangled, and that leads to the transmission of system information to the environment, and finally, the system loses its individuality. This approach claims that since the observer can’t control and consider all the degrees of freedom of the environment and has only access to the system,... 

One of the most important technologies in space missions is capability of moving satellites together with a predefined structure (virtual structure). This structure can reconfigure itself to any desired space mission and it is known as reconfiguration maneuver, in this maneuver all of the satellites have to follow needed virtual structure from any initial configuration to any desired second composition. In available virtual structure methods, there are a lot of limitations in maneuver because of algorithm constraints, in this project we try to extend available algorithm in virtual structure method and reach an algorithm which can start from any initial condition and complete the maneuver in... 

Today, the rapid and increasing growth of various human societies has led to an increased consumption of energy and the need for new resources. In fact, the excessive consumption of energy, especially fossil fuels, has caused adverse and sometimes irreversible effects on the human environment. Also, the consumption of different types of fossil fuels such as coal, oil, and natural gas, leads to a significant increase in greenhouse gases in the atmosphere. On the other hand, population growth and technological advancements in the last century have led to an increase in the demand for energy carriers. Therefore, the use of new energy sources instead of fossil fuels is an inevitable matter.... 

During the recent years, the emerging technology of photonic, on-chip communication has been widely explored to resolve the problems of traditional electrical communication in terms of performance and power consumption. Micro-Resonator (MR) as the photonic building block for optical comunication is very sensitive to temperature and process variation. Variation of resonance wavelength of a micro-resonator as a result of temperature fluctuations causes tremendous error for optical data routing through the waveguides, and reduce the reliability of network. A temperature-aware routing algorithm enables the network to tolerate fault and continue working properly. Temperature variation of MRs is a... 

In this thesis, we address the problem of joint Range, Angle and Doppler frequency estimation in FDA-MIMO radars. Target parameter estimation is among the most important areas of research in radar signal processing. In this field of research, there are numerous challenges to overcome, including low estimation accuracy, a scarcity of snapshots, and the high computational complexity of algorithms. For this reason, diverse methods have been developed to solve this problem. Each of these methods has its own features and capabilities, focusing on one or more of the existing challenges. The application of these methods also depends on various factors, including the signal structure, which is... 

Determination of ultimate bearing capacity of shallow foundations has been discussed since long time ago in many books and papers. Although this is not generally a new problem, there are still some problems which may be interesting to be investigated in detail using suitable computer programs and by application of appropriate soil models. Comprehensive surveys on bearing capacity coefficients of different foundations have been done by utilizing FLAC software. The failure of soil is governed by the Elasto-Plastic Mohr-coulomb criterion. New graphs and equations have been developed for determining the coefficients. The equations achieved in this study by numerical methods, have been compared... 

In this thesis, zero-divisor ideal graphs and geometric zero-divisor graphs are introduced and are partially studied. We begin by studying the relation between the zero-divisor graph and zero-divisor ideal graph associated to principal ideal rings. We also investigate some of the basic properties of the zero-divisor ideal graphs, including their girth and diameter. Then, we introduce the geometric zero-divisor graphs associated to reduced schemes and study their basic properties to some extent. Finally, we conclude by characterizing all reduced schemes whose associated geometric zero-divisor graph contains a vertex which is... 

The main object of this thesis is synthesizing poly(vinyl acetate)/ colloidal silica nanocomposites via emulsion and in-situ polymerization methods. At the first, nanocomposites were produced in the presence of poly(vinyl alcohol) as the protective colloid, ammonium persulphate as the initiator and sodium bicarbonate as the buffer in an aqueous solution. Then, structural, thermal, rheological, mechanical and surface properties of produced nanocomposites with various colloidal silica content (0.5 %, 1 %, 1.5 %) were evaluated by DLS, FTIR, SEM-EDS, DSC, TGA, dynamic and steady rheological tests, tensile and shear mechanical tests, AFM and static water contact angle. The particle size of... 

The basal focus of brand management in the field of brand extension is tracking brand equity that can serve as a strategic tool in order to creating and sustaining long-lasting and profound associations between brand and the customers. Tracking brand equity executed in means of understanding that to what extend firms succeeds on appreciating their brand values on mindshare.This study aimed to assessing the intangible brand equity of Mahan Air among its mindshare and also clarifying the status of Mahan brand life cycle through Brand Asset Valuator approach. This model was designed by Young & Rubicam (Y&R) institute and is utilized for evaluating the non-financial value of creditable... 

The rapid growth in demand for computational resources driven by new applications and services had led to establishment of new cloud data centers. Such Data Centers consume enormous amount of electrical energy resulting in high costs and carbon emissions. Dynamic Consolidation of virtual machines and turning idle hosts off allow cloud providers to reduce energy consumption. But consolidation of virtual machines may leads to quality of service(QoS) degradation and Service level Agreement(SLA) violation. One of the most important reasons for QoS degradation is the migration overhead, therefore the number of VM migrations should be controlled. Over the last few years, VM consolidation problem... 

All societies need energy to meet the basic needs of the people and to carry out the production processes. From 1850 onwards, the global use of fossil fuels (coal, oil and gas) for energy production increased, leading to a dramatic increase in the emission of carbon dioxide (CO2) into the atmosphere. Rising carbon dioxide and other greenhouse gases in the Earth's atmosphere and seeing adverse effects such as global warming have prompted the international community to replace fossil fuels with clean energy as much as possible. Geothermal energy as one of the clean, sustainable and extensive sources can be one of the available solutions to meet this need.Numerical modeling of geothermal...