Sharif Digital Repository

During recent decades, dramatic advances in Genetics and Molecular Biology, has provided scientists with enormous amounts of molecular genomic information of different living organisms, from DNA sequences to complex 3d structures of proteins. This information is raw data which their analysis can provide better understanding of genome mechanisms, discriminating healthy and tumor cells, predicting disease type, making drugs based on genome information, and many more applications. Here, one important issue is the inevitable use of computer science and statistics to analyze these data; such that according to the vast amount of data, would provide intelligent methods, which yield most accurate... 

Identification protocols facilitates two participants A and B to identify themselves to each other. Beside identification, A and B can exchange a secret value along with the identification process as the key exchange identification protocol.A secure key exchange identification protocol hould utilize perfect forward secrecy (PFS) property. PFS means if an attacker could compromise an entity in future and gain its long-term key, he cannot succeed to extract previous session keys. So, he will be unable to decrypt previous messages and they will remain secure. Because of the low power and storage of light devices, updating secret shared keys is a solution to reach PFS in such protocols. A major... 

Separation and identification of metal nanoparticles in surface water samples such as river water is very important. Nanoparticles specially metal nanoparticles have small dimensions can easily pass through from the body's outer immune system and disrupt biological function. Most of the nanoparticles have active surface so environmental contaminants can be absorbed on their surface and then can penerated in the body, and they may cause disease. Therefore determination of nanoparticles type and concentrations and their separation from the surrounding environment, especially surface waters is important. Separation and preconcentration of metal nanoparticles was done by using cloud point... 

Increasing the speed of marine transportation services for specific mission and rapidly movement of persons or product always have been considered major issue in maritime industry. In recent years different technology have been used by high speed vessels manufacturer for increasing the safety of crew and passengers at sea. Catamaran is one of the most important high speed craft in marine transportation industry. High speed catamaran nonlinear behavior in high velocity is causing longitudinal instability and large motions. Active control surfaces like hydrofoil and interceptor can be used for reducing high speed catamaran motions in waves. This control surfaces react an adequate action... 

Nowadays exoskeltons are developed because of improvements carried out in mechatronic technologies, to use in applications such as human rehabilitation and power augmentation. By reason of interaction between exoskeleton robot and human, an appropriate control strategy should be considered to implement regulated interaction force between them. As an example there are situations that a person wants to carry heavy load with this robot without suffering from weight of the load, so control of robot movements is of great importance. The aim of this thesis is dedicated to develop and implement a control strategy achieving minimum ineraction force in a 2 degree of freedom lower limb exoskeleton.... 

Radio-Frequency Identification (RFID) in many applications, namely supply chain management; access management; tracking commodity, people, and animals; and storage of medical information, to name but a few, be remembered as the most effective method of gathering information. Accordingly, accurate modeling and optimizing of this technology with attention to its daily development in varied applications, has a significant role. In this regard, some issues – that is – reader location, the number of tags that are controlled by a reader, and data communications of readers with central server, to name but a handful, are challenging and there are attemps to optimize the network in terms of cost,... 

Web applications and services have been developed and deployed with unprecedented speed, providing various important functionalities to the end user such as office applications, social networking, content sharing, education, and entertainment. Given its popularity and ubiquity, the Web also attracts the attention of malicious entities. Indeed, the Web and its global user community have observed various forms of attack in the past. Among these attacks, using the Web as a channel to distribute malware has become a prominent issue. This type of attack called drive by download attack. This issue has generated a great deal of attention from the security research community . Existing systems to... 

Total Energy consumed in the compressor stations severely affects the gas transmission costs. Currently steady-state optimizations are used to solve “Minimize Fuel Cost Problem” (MFCP) in gas transmission networks. But due to the fast changing demand and maintaining the linepack of network, these methods are not able to find best solution for MFCP. Control of natural gas transmission system is a challenging task due to the system large dimension, lots of operating constraints and small number of measurements compared to the number of system states. In this thesis it is first shown that most of the pipeline systems have a mild nonlinear behavior. A heuristic method for identification of large... 

Identification and control of nonlinear systems have been always such important subjects based on nonlinearities of many processes. For instance, identification and control of gas transmission networks can be mentioned as one of the challenging problems related to their complexity and existence of different variables. The purpose of this project is identification of a nonlinear model for defining a gas transmission network and implementing a model predictive control algorithm based on identified model. Hence, first, a volterra model is implemented for identification of a pH neutralization process and then, that model is used for identification of a gas transmission network. Finally, by... 

The person identification by Electroencephalographic (EEG) signals has attracted the researchers’ great attention in recent years and lots of investigations have been developed. An identification system seeks to identify a person in a database. The advantage of using EEG signals for person identification is the difficulty in generating artificial signals for imposters. But more works need to be done to use EEG based biometric in real-life and this thesis is one of them. In this project we classify the EEG signals for person identification using AdaBoost algorithm. Adaptive boosting (AdaBoost) is a machine learning technique for pattern classification in which the performance of the weak... 

Sensors are one of the most vital instruments in Nuclear Power Plants (NPP), and operators and safety systems monitor various parts of the NPP and control transients by analyzing the values reported by the sensors. Failure to detect malfunctions or anomalies in them would lead to catastrophic consequences. A new approach based on thermo-hydraulic simulation by RELAP5 code and Feed-Forward Neural Networks (FFNN) is given to detect faulty sensors and estimate their correct value which are two main objectives of the current study. This approach consists of two main parts; The first part, Fault Detection Hyper Block (FDHB), responsible for detecting faulty sensors, and the second part,... 

Among all biometric approaches, gait analysis is one of the most practical methods for human identity recognition. Gait has a lot of advantages over other biometrics like face recognition, iris recognition, fingerprint, etc. First and foremost, the gait data can be collected from a distance, and there is no need for subject’s cooperation. Another advantage of this biometric method is its cost-effectiveness and the fact that it does not need high-resolution images. But there are significant challenges in detecting and analyzing this feature. One of the most important challenges is decreased recognition accuracy caused by identity-irrelevant factors like camera viewpoint and changes in walking...