Sharif Digital Repository

According to necessity of analysis and detection of K-complexes and Sleep Spindles patterns which are the hallmarks of the second stage of sleep, in this thesis we aimed to introduce new methods in analysis and detection of aforementioned patterns in order to improve the results of previous methods. Also, we tried to find the relation between slow oscillations and spindles activity. In this project, in order to analysis the frequency components of Sleep Spindle, Bump modeling and STFT were used. Both of these methods confirm the spindles’ 8 Hz to 15 Hz frequency band and also their time duration between 0.5-2 seconds. On the other hand, we used modified matched filtering and also bump... 

There are a wide variety of radar systems that one of them is MIMO Radars. After a spark in communication in 1998 that developed MIMO communication, recently there has been a great attention towards MIMO radar systems. Researchers have studied this topic from several points of view. Generally, MIMO radar systems are divided into two categories: MIMO radars widely separated antennas and MIMO radars with collocated antennas. One of the important issues of widely separated MIMO radars, is the placement manner of receivers in the geometrical area. This radar’s performance is very dependent to placement of the antennas, because the performance is dependent to relative position of... 

Disambiguating concepts in language is one of the most challenging tasks in the field of natural language processing and computational linguistics. A sort of these ambiguities can be found in metaphorical and metonymic concepts. In the present study, we try to introduce the structure of the detecting and disambiguating system of metaphor and metonymy. Detection step is based on semantic valency of the verbs occurring within the subject and object positions and the disambiguation step on the key topical concepts. The data of the detection step involves semantic valency of the seven metaphorically and metonymically frequent verbs. First of all, the data were collected by extracting the... 

In this thesis a dynamical model is introduced for Phonocardiogram based on its morphology which is capable of generating synthetic signals with realistic morphology. The model is for normal Phonocardiograms which includes the two dominant heart sounds, namely the first and the second sounds, and is inspired by the Electrocardiogram dynamical model. In the proposed dynamical model each heart sound is modeled with several Gabor kernels. The ultimate goal of such dynamical model is to establish a model-based processing framework for Phonocardiogram. This framework is devised by employing the dynamical model equations within an Extended Kalman Filter structure, and the simultaneously recorded... 

During recent decade huge number of new malware samples and their complexity have caused challenges to malware detection procedure. additionally the use of kernel level rootkit has been grew up. while rootkits usually defeat current security products which are cheifly relied on Operating system for gathering information and also running, existing nti-rootkit solutions can not cover all kinds of rootkits.In this work we have studied the problem of kernel-level rootkits in Windows operating system. we believe that focusing on kernel drivers features, will result in an overall view needs for monitoring kernel activity of the rootkits. Thus with regards to proves for lower volume of obfuscation... 

Movement-Related Cortical Potentials (MRCPs) are a subset of Event Related Potentials (ERPs). The event that MRCPs are related to is the endogenous event of self-paced voluntary movement. Like many other ERPs, MRCPs have small amplitudes relative to the background EEG activity, making it difficult to detect them on a single-trial basis. Nevertheless, detection of MRCPs with good accuracy can be vastly benecial to automated rehabilitation systems and to Brain-Computer Interfaces. In this project, a new experimental protocol for MRCP is introduced and signals recorded using this protocol are analyzed. The protocol has been designed and recordings have been made by the author during the summer... 

Most existing face recognition methods require several gallery (training) images per person for optimally training the system. On the other hand, in many real applications of face recognition such as law enforcement, driver’s license and identification by passport, generally only one image per person is available. However, “the variations between face images with different illumination and gestures are almost always larger than image variations due to change in face identity”, Therefore, in this thesis we have considered face recognition with changes in ambient lighting conditions and viewing angles where only one training image per person is availabe. A method have been proposed in which we... 

The use of multiple-input multiple-output (MIMO) radar to overcome traditional radar weaknesses has received much attention in recent studies.For example, the detection of targets with low radar cross section (RCS) level is still very difficult since the target can be seen only from one side. MIMO radars by diversity of locations or waveforms solve this problem. One of the fundamental problems in the design of MIMO radars is optimal detectors.This problem has been investigated in recent years under various assumptions. We studied this subject under some assumptions such as single point target, Swerling scattering models for radar cross section and Gaussian interference.In this paper we... 

In recent years, hardware Trojans (HTs) have become one of the main challenging concerns within the chain of manufacturing digital integrated circuit chips. Because of their diversity in chips, HTs are difficult to detect and locate. This thesis attempted to propose a new improved method for detection and localization of HTs based on the real-time logical values of nodes. The algorithm extracts the nodes with special attributes. At the next stage, the nodes with the greatest similarity in terms of logical value are selected as targets. Depending on the size of the circuit, the extraction continues until a sufficient number of similar nodes has been selected. The logical relationship between... 

Using flapping motions, birds produce aerodynamic forces required to fly. Flapping wing aerodynamics is one of the most complicated problems in unsteady aerodynamic field. Experimental study on the structure, the way of production and growth and the feasibility of controlling the leading edge vortex are the main goals of this research in order to improve the aerodynamic performance of flapping wings. Since leading edge vortex structure appears in both upstroke and downstroke of a complete storke in flapping motion, controlling the structure in one of the half-storkes can provide the possibility of having a better aerodynamic performance. In this research, the wing is designed and... 

There are several methods for EEG state detection, and there are still many challenges. Switching Kalman Filter (SKF) is a suitable approach for state detection, which has been used in various applications such as QRS detection in ECG signal, apnea detection using ECG signal, and also hand path detection using EEG signal. Our goal here is to use Switching Kalman Filter (SKF) in order to detect changes in EEG signal, and in particular in sleep. In other words, we want to detect Sleep Stages. Here, detecting Sleep Stages will help doctors diagnose and treat diseases. There is a Kalman Model for each Stages of Sleep in SKF, that I model it with a AR model. In addition, SKF switch is a state... 

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,... 

During the last few years, the study of urban environment structures is considered as a research field of interest in remote sensing. In satellite observations of the earth's surface, continuous imaging in terms of time and space has caused the remote sensing technique to be proposed as a useful and efficient tool for the analysis of urban areas. Obtaining quantitative spatial information from the urban environment in fields such as determining the height of buildings plays an essential role in urban planning, monitoring damage to buildings, establishing communication bases and digital cities. During the last two decades, the use of Tomosar approach in order to reconstruct the structures of...