Sharif Digital Repository

The main purpose of the thesis is Digital image Processing using the sparsity of image. The issue could be described in two ways. First is reconstruction of missed blocks of an image based on the sparsity of image in the transform domain and second is impulsive noise removal using the sparsity of noise in the spatial domain. In the first approach we will review Guleryuz method and simulate and analyze it. In the second approach, two new methods named RDE and Knockout will be introduced. These methods try two remove the impulsive noise of an image using its sparseness. RDE method is a development of conventional methods, but Knockout has a completely new idea. We will show that Knockout is... 

A Mobile Ad hoc NETwork (MANET) is a self-configuring network that is formed automatically by a collection of mobile nodes without the help of a fixed infrastructure or centralized management. In recent years, the use of MANETs has been widespread in many applications, including some mission critical applications, and as such security has become one of the major concerns in MANETs. Due to some unique characteristics of MANETs, prevention methods alone are not sufficient to make them secure; therefore, detection should be added as another defense before an attacker can breach the system. In this thesis, we have expressed some well-known and related intrusion detection systems. Besides we have... 

Mount Polley Tailings Storage Facility (MP-TSF) failed on its perimeter embankment on August 4, 2014, when its 9th construction stage has just been completed. The failure releasedmillions of m3 of toxic tailings, supernatant water and construction materials todownstream. Up to this point, some research studies have been conducted into the causes of the failure. These studies have considered the stability of the TSF in different stages of its construction as well as in the last stage. The aim of the present study is to investigate the causes of the very failure, using numerical methods by the aid of the finite element based software, PLAXIS 2D. In the present study, the results of the... 

The precise positioning of magnetic catheters is critical for a range of medical procedures, ensuring efficacy while minimizing potential complications. This research delves into the position control of a magnetic catheter influenced by an external permanent magnet. Due to the intricate and complex equations describing the plant's behavior, a neural network approach was deemed suitable for modeling. Using a 5 degree of freedom manipulator carrying an external permanent magnet, data was gathered from real-world positionings, tracking the coordination of the magnetic catheter's end. These data points served to train the neural network, subsequently allowing for an effective simulation of the... 

In the late 1980s, the International Maritime Organization started working on reducing air pollution by ships, and the result was the approval of Annex 6 of MARPOL and its mandatory implementation since 2005. Since then, due to the increasing importance of pollutant emissions in the maritime transport industry and the stricter regulations of the International Maritime Organization and the high cost of fuel for ships, ship owners are looking for ways to reduce fuel consumption. For this purpose, various activities related to reducing the fuel consumption of ships were carried out. Among these, the use of energy saving devices can be a solution. Recently, the hull vane, as a fixed underwater...