Sharif Digital Repository

In thi¬s thesis we studied 3d reconstruction of synchronized multi-view videos containing dynamic scenes of complicated deformable surfaces and fast motions, such as soccer scenes. Our pupose is to extract shape and motion of scene simultaneousely via a spacio-temporal framework. To this end, we translate our problem to a registration problem both in stereo and temporal pairs. We review 3D reconstruction methods and their related concepts like stereo correspondence and scene flow. This review is necessary to choose the best solution.In proposed solution we formulate 3d recnstruction problem as an optimization problem.Using variational framework we integrate error functional over image planes... 

Polar codes were introduced by Arikan in 2009. These codes are the first family of codes that with low encoding complexity and successive cancellation decoder, can achieve the channel capacity. Polar codes, at first were implemented for channel coding, but in 2010 performance of these codes in binary and q-ary alphabet source was studied. It is shown that these codes can perform efficiently in channel coding and source coding. On the other hand, one of the most important continuous sources are Gaussian sources. Due to the importance of Gaussian sources and good performance of polar codes, we try to evaluate the performance of these codes in Gaussian sources. Note that, these codes have... 

Fired heaters are large and complex items used in process plants. Tubular furnaces used mainly in chemical, petrochemical, and refinery process plants. For many process plants, the fired heater performance will determine process unit run-length. High tube metal temperature and coking in the process-fired heaters is one of the serious problems of process plants. Coke forms because the oil in tubes is no longer thermally stable at the operating conditions. Oil film temperature in the inside wall of tube somewhere that, process fluid has highest temperature and lowest velocity. Therefore, process fluid peak film temperature will determined rate of coke formation. This temperature is dependent... 

Previous studies and field evidences show that creating appropriate interactions between sales and marketing departments is a challenge for many organizations. The main objective of this research is to develop and elaborate a conceptual framework in which "cooperation mechanisms" between sales and marketing and it’s "consequences" determined and provide an explanation that shows how configuration of sales and marketing relationship affects its consequences. The results show that "organizational ambidexterity" is the core consequence in proper architecture of the relationship between sales and marketing. In the strategy literature, combination of the dual capabilities of exploration and... 

Today, the increase in greenhouse gases and the accumulation of thesegases in the atmosphere has caused a destructive environmental impact. Transportation systems in the country consume 25 % of the energy, which isalso the main cause of air pollution in addition to the imposition of fuelconsumption and fuel imports this has led to the design and deployment of vehicles with new technologies, necessity and importance that hybridvehicles is one of the new technologies. Considering that the average speedin road traffic is low and internal combustion engines have lower efficiencyand higher emissions, the hybrid vehicle reduces the current costs (fuelconsumption) and external costs (air pollution)... 

The advent of maturing fuel cell technologies presents an opportunity to achieve significant improvements in energy conversion efficiencies at different scales and environmental conservation simultaneously. This work deals with modeling, simulation and control of planar solid oxide fuel cell with internal reformer. The presented model is based on conservation laws (mass, energy, and momentum), besides an electrochemical model with all sorts of voltage losses (ohmic losses, activation overpotentials, and concentration overpotentials). Methane steam reforming, water-gas shift reaction, and hydrogen oxidation are the main reactions in this modeling scheme. The obtained governing equations lead... 

Structural changes in the energy sector, including the need to diversify sources of energy supply, security of supply, energy consumption growth in developing countries, rising oil prices and the exhaustibility of fossil fuel reserves, environmental issues, increased consumption of petrochemical products etc., has led to increased share of natural gas in primary energy supply. Iran has a wide range of options to use natural gas endowment. The present research aims to develop a model for optimal allocation of natural gas to various applications.The gas distribution system is modeled in the present study. Technical onstraints together with economic characteristics are considered in the model.... 

Large deviation principle (LDP) for stochastic differential equation is one of the interesting and modern topics in stochastic analysis. Principally, this theory gives the rate of convergence to the solution of the corresponding deterministic equation when the noise tends to zero. The study of LDP for SDE’s has been initiated by M. Freidlin and A. Wentzell and then has been considered by many other researchers. Freidlin andWentzell divided the interval [0, T] to small subintervals and considered the diffusion coefficient as a constant on any small subintervals. Then the problem is reduced to the additive noise case. But using the contraction principle, the study of LDP for an equation with... 

The purpose of this study is the simulation of Printed Circuit Board’s thermal decomposition process based on the latest updated environmentally safe methods, to produce valuable materials. The method used is an efficient process for recycling printed circuits to prevent harmful environmental consequences of inadequate methods, and also to obtain a small amount of fuel for recycling. In this research, the pyrolysis process of printed circuits has been simulated using Aspen Plus software. In the simulation, a fluidized bed is used as a pyrolysis reactor and also a combination of two mechanisms is used to determine the kinetics and reactions in the reactor. The desired product in this process... 

Ultrasound waves have been one of the passions of researchers of different fields for many years. In recent decades the potential of ultrasound waves for trapping and manipulating micro-particles has been noted by many researchers. “Acoustic Tweezers” is the name given to this application of ultrasonic devices. The advantages of this device over its optical counterpart, named “Optical Tweezers”, are its low price, ease of use, biocompatibility and its capability of being used in opaque media. In acoustic tweezers, particles can be trapped either by making standing acoustic waves, or by making highly focused narrow beams and trapping the particles in potential wells. In this research... 

In this work, a high-order accurate gas kinetic scheme based on the compact finite-difference Boltzmann method (CFDBM) is developed and applied for simulating the compressible rarefied gas flows. Here, the Shakhov model of the Boltzmann equation is considered and the spatial derivative term in the resulting equation is discretized by using the fourth-order compact finite-difference method and the time integration is performed by using the third-order TVD Runge-Kutta method. A filtering procedure with three discontinuity-detecting sensors is applied and examined for the stabilization of the solution method especially for the problems involving the discontinuity regions such as the shock. The...