Sharif Digital Repository

The crypto-processors are used for encryption and decryption of the sensitive and important information. A crypto-processor converts input plaintext to ciphertext by an input key using a particular cryptographic algorithm. It also converts ciphertext to plaintext by the same or another key. Cryptographic standards are divided in two types: symmetric key algorithms (private key) and asymmetric key algorithms (public key). Current processors generally support only one or a few number of cryptographic algorithms. The motivation of this project is design and implementation of a multi-standard crypto-processor which supports the most of symmetric and asymmetric cryptographic algorithms, such as... 

With the advancement of the technology, Design of low power devices such as biomedical systems, wireless sensor network, portable devices and … has received more attention. Digitally controlled oscillator (DCO) is one of the sub-blocks in systems such as all digital phase locked loop (ADPLL) which consumes the major power of the system. Therefore, Design of a low power DCO will decrease the power consumption of the system significantly.
In this thesis, a digital control oscillator which is ultra low power is design for system on chip applications. Coarse-Fine architecture is used with binary weighted cells in this design. For the Coarse tuning stage, a new delay cell is proposed which... 

Low power and high speed analog-to-digital converters (ADCs) are the key elements of communication and computing systems. There are several ADC structures such as delta-sigma, flash, pipeline, and successive approximation register (SAR) for different applications, albeit SAR ADCs are natural candidates of onchip designs for their low power and scalability benefits. Nowadays, SAR ADCs are widely being used in low-power moderate-resolution applications which need several tens of MS/s to low GS/s sampling rates. By virtue of the technology scaling power consumption of digital parts of a SAR ADC is reduced significantly. As a result, in a SAR ADC the power consumption of the digital-to-analog... 

The popularity of Internet-based video services has increased in recent years, while in 2017 reached nearly 70% of the total Internet traffic. Changes in network status and the problems that result in the user experience leading to poor quality of the video watching experience, online video players have been using adaptive algorithms to match the quality of the received stream to the current state of the network. Different algorithms have been proposed for optimization of matching operations, but due to the different and sometimes contradictory nature of the constituents of the quality of user experience, the priority and focus of each of these algorithms is based on different challenges... 

Increasing demand for high-speed and high-resolution ADCs as much as low-power ones and on the other hand, the obstacles in the way of reaching them make calibration and compensation methods more significant for obtaining ADCs with the better specs. Among the cases which need modification, the modification of C-2C-based SAR ADCs, which can decrease the power significantly, and the modification of time-skew error of time-interleaved ADCs, which is the main and the most challenging error in this type of ADCs, could be the two of the effective ways to making the State-of-the-Art ADCs. In this project for the first time, a novel compensation method for C-2C parasitic charges is proposed which... 

Nowadays, there is a focus on developing a propulsion system with higher efficiency and performance in comparison to conventional systems. Many diverse systems have been designed for the vessel propulsion and everyday, utilizing new ideas, their performance and energy consumption are being improved. Direct use of steam energy is a noble and new idea. In this research, the steam jet propulsion system has been explained and current worldwide research on the topic has been investigated. Considering the shortage of primary data in the field and the novelty of subject, required information for the manufacturing of a sample model of this special propulsion system has been gathered and a design for... 

The popularity of Internet-based video services has grown dramatically in recent years, with the figure now estimated to be around 75 percent of total bandwidth consumption and it will increase to 82 percent by 2021. The growth of video services, as well as the advent of 360-degree videos and more real-world experience in it than conventional videos, have led companies such as Google, Facebook, and others to embark on this field of research and implementation to make it an epidemic. One of the major issues that will challenge the implementation of this video service on the network is the high volume of these videos that do not make it possible for everyone to use them. It is necessary to... 

Analog to digital converters is one of the main building blocks of today's circuits. These circuits play an important role in signal processing. Since these circuits consist of analog and digital sections, a large percentage of the power consumed in a circuit is allocated to this section. Therefore, in applications such as medical devices, wearable applications and wireless technology where power control is very important and necessary, reducing the power of analog to digital converters is very important. One of the simplest analog-to-digital converters from the design point of view is Successive Approximation Register (SAR) analog-to-digital converters. This type of analog-to-digital... 

A DLL-based frequency synthesizer that has the capability of producing fractional multiples of the reference frequency is designed and implemented in this thesis. The new structures for producing fractional multiples of reference frequency with DLLs are also presented. The designed frequency synthesizer is not a Sigma-delta modulator for synthesizing. This structure has a low jitter and phase-noise, low chip area, low settling time and a good stability due to its DLL-based nature. Also, a systematic model for simulating DLLs in MATLAB Simulink is proposed that is very efficient for giving a better insight to designing of DLLs. The settling time of the proposed topology for DLL is 2.5us. The... 

High speed data converters are very often used in telecommunication systems. Since these systems are increasingly used in mobile form reducing the power consumption in these circuits is of great importance. The goal of this project was to design a pipeline 10 bit converter for a sample rate of 40 M sample/s with a power consumption of 20mW for the input level of 1Vp-p and a 1V power supply in 0.13μm CMOS technology. To reach these goals a number of low-power techniques are proposed in various levels of abstraction. In system level, the sampling and feedback capacitors, as well as the stage resolution of the ADC is optimized analytically which leads to simple back-envelope formulas to... 

Due to the developments in technology, digital equipments, networks, storage devices, a lot of videos have been produced so far. Due to the dayly high growth rate of videos and their data, organizing and managing of them is difficult for applications such as interactive television, digital libraries, video surveillance, etc.However, for these kinds of usage from videos, at first the video will need to decompose into a hierarchical structure such as shot, scene, subscenes, scene and story unit. In order to achieve these goals, after the determination of shot boundaries and the allocation of key frames for each shot, similarity between each two shots are measured using key frames. According to... 

Nowadays, surveillance cameras are an integral part of the transportation management center. On one hand, developing of surveillance cameras around the cities and on the other hand, increasing costs of driving accidents, makes it necessary to use the automatic behavior analyzing systems on video sequences. The scientists’ focuses on detecting unusual events as one of the most important usage of video analysis, and recently, the algorithms of unusual action detecting had an impressive development by using the machine learning methods. In this research, the existing unusual event detection methods and in special, traffic unusual activities will place under scrutiny, and we suggest an algorithm... 

Throughout localization algorithms, sound source localization has received much interest using microphone array. Applications like tracking and determining angle of acoustic signal arrival have been combined with array processing techniques in the previous decade. Distributed micro sensor array have been suggested for a wide range of nowaday’s localization algorithms. The major goals are monitoring the environment, distinction, and pursue some phenomenon. This type of networks can be utilized for military application in tracking acoustic sources. Today’s advancement in technology allows implementation of the ultra low cost and low power integrated circuit for such application in the form of... 

Sound source localization has been one of the fundamental problems in many areas, including radar, teleconferencing or videoconferencing, localization of earthquake epicenters and underground explosions, microphone arrays, robots, etc. All of sound source localization ideas are like human auditory system. The human auditory system is a complex and organic information processing system. It can feel the intensity and spatial orientation and other information of sound. The distance of the two ears on our head is about 20cm. When the sound reaches each ear, there are small time difference, intensity difference and phase difference. After analyzing these differences by the brain, the human can... 

In this work we present a surveillance video retrieval system based on Topic Models. We’ve shown that employing Dynamic Programming improve the effectiveness of Topic Model based retrival. In the other hand proposed method has the accuracy near to the low-level features based methods. Lightweight database is the major advantageous of propsed method over the low-level features based methods. In our work storage space occupied by database decreases from 42 MB to only 0.4 MB for the mit dataset. Moreover lightweight database strikingly speeded up the retrieval process, for example retrieval process in proposed method is about 24 times faster than low-level features based systems. Furthermore in... 

Volatile organic compounds (VOCs) has harmful environmental and health effects and appropriate processes are needed to remove them from industrial and indoor environments. In this study, formaldehyde as one of the most toxic VOCs was investigated. Various methods have been developed to remove formaldehyde, however due to the to their low removal efficiencies, secondary pollution, and low energy efficiency, development of alternative methods will be beneficial. In recent years, the use of a combination of non-thermal plasma and catalyst technologies, called plasma-catalytic hybrid reactors, has provided significant results in the fields of chemical synthesis and removal of pollutants. In the... 

Simulation of cardiovascular system functionality during various physiological conditions is essential at different diagnostic and clinical levels. A first step in studying the roots of cardiovascular diseases and abnormal activity is to study a practical yet complete model of the cardiovascular system. In this thesis we introduced a new approach for defining the distributed model of the cardiovascular system. Initially, we chose an appropriate subsystem, namely Arch of Aorta, and proposed a distributed model for it. The elements of the proposed model were nonlinear RLC elements that simulate resistance, blood viscosity and vessel elasticity respectively. To minimize the system complexity,... 

The thesis is about transit network scheduling problem and aims to minimize waiting time at transfer stations. The problem is formulated as a mixed integer programing model that gives departure times of vehicles in lines so that passengers can transfer between lines at transfer stations with minimum waiting time. The model is expanded to another model by considering an extra stoping time of vehicles at transfer stations as a new variable set. By calculationg the optimal value for these variables, transfers could be done in a better condition. The sizes of the models are small enough that the models can be solved for small and medium size networks using regular MIP solvers. Moreover, a...