Sharif Digital Repository

In Mobile Ad hoc Networks (MANETs), nodes depend on each other for routing and forwarding their packets. However, to save power and other resources, nodes belonging to independent authorities may behave selfishly, and not cooperate in network activities. Such selfish behaviour poses a real threat to the proper functioning of MANETs. To cope with this situation, a motivation stimulation mechanism is required to provide sufficient incentives for nodes to forward other nodes’ packets. One Appropriate approach is to have network nodes paid in order to motivate them to cooperate with protocol. To achieve truthfulness, the payment based on the cost of transmission of packets. Since the mentioned... 

With the dramatic advancements in information technology and the industry requirements for security and privacy, proof systems play a crucial role in cryptography. Among the vast variety of proof systems, succinct non-interactive arguments (SNARG) seem to be the most appealing class of proof systems, due to their attractive properties. SNARGs are usually made up of two constructive components, namely the information theoretic part and the cryptographic part. The GKR protocol was introduced as a proof system for a tractable family of languages called “log-Space Uniform Circuits”. The log-space uniformity is a necessary condition for the protocol to be succinct. Hence, it is not possible to... 

With the dramatic advancements in information technology and the industry requirements for security and privacy, proof systems play a crucial role in cryptography. Among the vast variety of proof systems, succinct non-interactive arguments (SNARG) seem to be the most appealing class of proof systems, due to their attractive properties. SNARGs are usually made up of two constructive components, namely the information theoretic part and the cryptographic part. The GKR protocol was introduced as a proof system for a tractable family of languages called “log-Space Uniform Circuits”. The log-space uniformity is a necessary condition for the protocol to be succinct. Hence, it is not possible to... 

The human action recognition is one of the most important concepts of computer vision in recent decades. Most of the two dimensional methods in this field are facing serious challenges such as occlusion and missing the third dimension of data. Development of depth sensors has made easy access to tracking people and 3D positions of human body joints. This Thesis proposes a new method of action recognition that utilizes the position of joints obtained by Kinect sensor. The learning stage uses Fisher Linear Discriminant Analysis (LDA) to construct discriminant feature space. Two types of distances, i.e., Euclidean and Mahalanobis, are used for recognizing the states. Also, Hidden Markov Model... 

The non-stationary nature of brain activity signals and their many inter-subject differences have created many challenges in the practical applications of emotion recognition based on electroencephalogram (EEG) signals, such as brain-computer interfaces. In such a way, the use of traditional classifiers in classifying these signals leads to a significant decrease in accuracy when applying the classifier to a new subject. Domain Adaptation methods seem to be an effective way to solve this problem by minimizing the difference between the EEG signals of different subjects. But in the basic techniques for domain adaptation, looking at all subjects' data in the same look causes the loss of a part... 

The aim of this thesis is to investigate the passive wrapping of nanoparticles by a lipid membrane in the uptake process using molecular dynamics computer simulations. The simulations are carried out by the Virtual Cell Model (VCM) software package, a computational framework that creates a large scale coarse-grained multi-component cell model developed by Prof Mohammad Reza Ejtehadi’s Soft Matter Group at Sharif University of Technology. VCM can model the dynamics of different parts of the cell and investigate their mechanical properties.A chapter of this thesis contributes to further development of the membrane model used in the VCM to simulate nanoparticles interactions with a membrane.... 

A probabilistic method is presented for identifying the dynamic soil-foundation stiffnesses of building structures. It is based on model updating of a Timoshenko beam resting on sway and rocking springs, which respectively represent the superstructure and the soil-foundation system. Unlike those previously employed for this particular problem, the proposed method is a Bayesian one, which accounts for the prevailing uncertainties due to modeling and measurement errors. As such, it yields the probability distribution of the system parameters as opposed to average/deterministic values. In this approach, the joint probability density function of the parameters that control the flexible-base... 

In this project, a novel action recognition method, named Fisherposes, is proposed, which is improved by several space-time (spatio-temporal) methods afterwards. The proposed method utilizes skeleton data obtained from Kinect sensor. First, pre-processing is performed in which the scales of bodies are canceled and the skeletons become aligned in order to make the method robust to location, orientation, and scale of people. In Fisherposes method, every action is defined as a sequence of body poses. Using the training samples for the poses, a Fisher subspace is created which we name it Fisherposes. Moreover, a novel distance measuring function, named regularized Mahalanobis distance, is... 

Continuous Blood Pressure monitoring can provide invaluable information about individuals’ health conditions. However, BP is conventionally measured using inconvenient cuff-based instruments, which prevents continuous BP monitoring. This work presents an efficient algorithm, based on the Pulse Arrival Time (PAT), for the continuous and cuff-less estimation of the Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), and Mean Arterial Pressure (MAP) values. The proposed framework estimates the BP values through processing vital signals and extracting two types of features, which are based on either physiological parameters or whole-based representation of vital signals. Finally, the... 

Brain states analysis during consciousness is emerging research in brain-computer interface(BCI). Emotion recognition can be applied to learn brain states and stages of neural activities. Therefore, emotion recognition is crucial to the analysis of brain functioning. Electrical signals such as electroencephalogram (EEG), electrocardiogram (ECG) and functional magnetic resonance imaging(fMRI) are frequently used in emotion recognition researches. Convenience in recording, non-invasive nature and high temporal resolution are the factors that have made EEG popular in brain researches. EEG can be used to identify brain region activity solely or the connectivity of various regions in time in the... 

In Iranian Sign Language (ISL), alongside the movement of fingers, the movement of the lips is also essential for to perform words completely and correctly. The purpose of current study is to provide an automated lip-reading system using deep neural networks and implement it on Rasa social robot; So that the robot can recognize a limited number of specified Persian words. To do this, we propose an automated lip-reading system based on convolutional neural networks and long short-term memories. Convolutional neural networks in extracting features from images and long short-term memories in modeling temporal dynamics have achieved good results. We have also recorded a database in Persian... 

Hypertension precvalence is 24 and 20.5 percent in men and women, respectively. Continuous Blood Pressure monitoring can provide invaluable information about individuals’ health conditions. However, BP is conventionally measured using inconvenient cuff-based instruments, which prevents continuous BP monitoring. This work presents an efficient algorithm, based on the Pulse Arrival Time (PAT), extracted from Electrocardiogram (ECG) and Photopletysmograph (PPG), for the continuous and cuff-less estimation of the Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), and Mean Arterial Pressure (MAP) values. Methods: The proposed framework estimates the BP values through processing vital... 

Different perceptual, cognitive, and emotional situations results in a kind of information flow in the brain by means of coordinated neuronal oscillations. Analysing these oscillations, especially synchronizations of different brain regions, can illustrate the brain response to the aforementioned situations. In the literature, connectivity between brain regions is divided into the three groups of structural, effective, and functional, s.t. the first one referes to the connectivity between nearby regions, while the second and third ones focus on the synchronization of oscillations of arbitrary located regions. Although EEG is not the best choice for analyzing functional connectivity between...