Sharif Digital Repository

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... 

Molecule of DNA is one of the most important biomolecule in cell which contains genetic information to supply the required proteins for body. Evidence shows prefered binding sequence for proteins exist to interact with proteins which this preference is determined not only by specefic chemical interactions between DNA and protein, but also specific suitable geometrical arrangements of DNA have important role to inding DNA oligomer and protein, such as winding DNA around histon to creating nucleosome is related to curvature and deformability of DNA. Thus knowing elastic behaviour and properties of DNA helps us to approach the answer of such questions. Despite the recent dvancement in labratory... 

Dynamic spectrum access with the aid of cognitive radio (CR) technology is a viable solution to spectrum scarcity. There are many military and emergency applications that require the use of cognitive radio ad-hoc networks (CRAHNs). In these net- works, nodes must first find each other in a wide spectrum and then exchange their desired data. The process of finding each other in a multichannel environment is a challenging task and is usually known as rendezvous. Since rendezvous is the first step in communication, disrupting will disable the nodes from establishing proper communication sessions. That results in a drastic degrade in the performance of the network. Therefore, it is important to... 

Hydroxyapatite (HA) is the most substantial mineral constituent of a bone which displays splendid biocompatibility and bioactivity properties. Nevertheless, its mechanical property is not utmost appropriate for a bone substitution. Therefore, a composite consist of HA and a biodegradable polymer is usually prepared to generate an apt bone scaffold. In the present work polycaprolactone (PCL), a newly remarkable biocompatible and biodegradable polymer, was employed as a matrix and hydroxyapatite nanoparticles and nanorods were used as a reinforcement element of the composite. HA/PCL nanocomposites were synthesized by three new in-situ sol-gel processes using a diverse range of phosphorus and... 

A grid simulator is a system for testing various types of grid-connected devices, such as inverters of renewable energy sources, chargers, power supplies, etc. In this project, the design and implementation of a 3 KVA three-phase regenerative programmable AC current source is presented. In the future, this structure can be used as a grid simulator. The topology used for the current source is a two-level three-phase AC to DC converter. The current source can operate in constant current (CC), constant power (CP), constant impedance (CI), and constant voltage (CV) modes. In the constant current operating mode, the user sets the amplitude and phase of the 1st, 5th, 7th, 11th, and 13th harmonics... 

With development of power electronic science and with the existence of different power electronic converters in this field, the need for improving their operation and the fault detection methods of these converters, the need for simulation and test of them is strong felt. However, experimental constrain such as damage risks, reliability, costs, and so on obviate the need for making the converter and the need for testing it and its controller. Accordingly, we do the testing on a special platform for Real-Time simulation.Control/protection platform needs to be tested and its functionality should be verified prior to installation and commissioning.Testing in theReal-Time simulator environment... 

Online advertisements have captured a major part of websites and mobile applications nowadays. In this kind of advertisements, as soon as a user interacts with a website or a mobile application, we have to decide which ad to show in a fraction of a second. In online advertising systems, revenue increases only when a user clicks on an ad banner or when they interact with the ad. So in order to select the best (most profitable) ad banner, the probability of clicking on or interacting with the ad banner must be estimated and then the most profitable ad will be selected.So one of the most essential problems in online display advertising, is estimating the probability of the click on a certain... 

Nowadays, with the increasing number of polyethylene terephthalate wastes, the issue of its recycling has become very important. Among the problems of polyethylene terephthalate recycling are its loss of crystallinity and mechanical properties. Recycled polyethylene terephthalate does not have the properties of new polyethylene terephthalate and using its mixture with other materials is an effective way to remove its waste from nature and return it to the production cycle. The aim of this study is to produce a mixture of recycled polyethylene terephthalate with polycarbonate and glass fibers with mechanical properties such as good impact strength, which ultimately leads to the production of... 

In wireless powered communication networks (WPCNs), wireless nodes are charged via an access point. In these networks, an access point transfers power to the nodes, and then, the nodes use the received power to transmit their information to the access point. Due to the wireless transmission of the information, eavesdropping of it is an important vulnerability in these networks. The conventional method to resolve this security problem is using cryptography algorithms. However, this method needs key management and complex encryption algorithms to be used by the nodes, which may not be applicable. Physical layer security (PLS), which uses the channel characteristics, is a more suitable way to... 

Magnetic gels and ferrogels are smart composite materials made by combining magnetic particles in a polymer matrix. These materials have been considered due to their special properties such as deformation and change of mechanical properties in the presence of external magnetic field. Having polymer properties along with the magnetic properties of metals, have led these materials to many uses such as drug delivery and artificial muscles. The increasing use of these materials has led researchers to continue research in the field of modeling ferrogels. Due to the porous nature of ferrogels, the ability to absorb a lot of liquid and their large deformations in the magnetic field, modeling of... 

Automatic theorem proving has been attractive in artificial intelligence (AI). The aim of the usual automatic theorem proving methods is applying of the mathematical logic rules to decide intelligently, and reasoning automatically. In contrast the aim of our research is to apply computers abilities and artificial intelligence methods to simulate human abilities to prove mathematical theorems. For this purpose, we invent a typed formal language (TFL) to describe mathematical theories. The language must be clearly computable and should cover the First Order Logic (FOL) and the usual mathematical sentences. Then some algorithms and inference rules to compare sentences conceptually are... 

Bioorthogonal chemistry defines any reaction, inside or outside the living systems, without interfering with native chemical processes and 3dimensional structure of proteins. In these types of reactions water is the sole solvent; a neutral pH is required; the temperature must be up to 40 oC. The kinetics of reactions must be on the hour scale and the nontoxic reagents with low concentration must be used. One of the simplest methods of visualizing protein molecule is covalent attachment of fluorescein to protein. In this work several fluorescent compounds were synthesized. These novel compounds include acylchloride fluorescein, N-hydroxysuccinimide fluorescein, thiophenol fluorescein, and... 

The Smith Predictor does not work for unstable plants; therefore a lot of modifications have been proposed in order to solve this problem. In this project, advantages and disadvantages of most of these methods are studied in a general framework and based on Diophantine equation and using pole-placement technique. a discrete control scheme for unstable processes has been proposed. This structure can be used for non-minimum phase and stochastic processes. Robust stability of the suggested control structure has been shown. Performance of the proposed method is compared with previous works through computer simulations and its superiority for robust stability, load rejection; set-point tracking... 

Inlet flow of afterburners comes from the burnt products of the primary combustion chamber. The fuel is injected and the mixture is ignited to form a flame which is stabilized behind a flameholder in the afterburner. Flame stability stems from wake (recirculation zone) of flameholder. With the aid of high residence time of flow behind the flameholder reactants get the time to catch activation energy. Some parameters like oxygen content, mass flow rate, inlet temperature, and nozzle area ratio play an important role in afterburner combustion efficiency and flame stability. In this study we focused on afterburner combustion stability in GE J85-21 engine. This engine will be in service through... 

In this study in-situ Al/Al3Ti was fabricated by mechanical alloying, hot extrusion and subsequent heat treatment. First, initial pure powders of Al and Ti were mechanically alloyed with 5 weight percentages of Ti for 40 hours. The as-hot extruded samples containing 5 wt% of initial Ti particles, were exposed to heating at 600 oC for various time intervals up to 10 hours. Microstructure analysis by OM and SEM proved that in-situ Al3Ti phase was formed as a layer around Ti particles by solid reactive diffusion between Al and Ti particles. After 10 hours of heating, all the Ti particles were consumed and transformed to Al3Ti. Mechanical properties of samples were investigated by Brinell... 

Nowdays, it has been shown that protein misfolding is involved in more than forty diseases including Alzheimer’s and Parkinson’s. Alzheimer’s disease is one of the most common neurodegenerative diseases that disrupts brain function. The main cause of this illness is due to formation of extracellular amyloid plaque from a 42-amino acid-peptide called amyloid beta. Amyloidosis is caused by missfolding of peptides and proteins mainly because of physical and chemical changes in biomolecule or their environment.
Therefore, in this dissertation, using synthetic and recombinant abeta peptide, kinetic of amyloidosis was examined. Ultrasmall peptides (three-amino acid), containing branched chain... 

The hierarchical multi-scale approach is one of the most powerful techniques that takes the advantage of different scales and succeeds the limitations of each method in a way that the large systems in coarse-scale can be simulated with atomic precision. In this thesis, the hierarchical atomistic-continuum multi-scale method is developed for modeling the phenomena with non-homogenous deformation, large deformation and plastic behavior. In this regard at first, an atomistic-based higher-order continuum model is formulated in the framework of nonlinear finite element method to present the geometrically nonlinear behavior of nano-structures. The efficiency of higher-order Cauchy-Born hypothesis... 

Hyderogels are hydrophilic polymers with three dimensional network structure, due to their high water absoption, their application to life and industry is increasing from day to day, such as tissue engineering, actuators and sensors, drug delivery and therapeutic treatment. In this project, it has been attempted to produce polyacrylamide/alginate double network hydrogels with the use of graphene oxide nanosheets to indicate that it is possible to combine toughness and self-healing in a hydrogel with the opposite nature of each other. To evaluate mechanical properties, uniaxial tensile test and loading-unloading test were used. The results indicate that increase the weight ratio of acrylamide...