Sharif Digital Repository

Today, considering the global demand for reducing greenhouse gas emissions, rechargeable batteries are considered as a source of energy in electric vehicles, hybrid electric vehicles and smart grids. In all these applications for secondary batteries, the battery management system requires an accurate estimate state of charge of each cell. However, this estimate is difficult particularly for battery aging. In this study, a lithium-ion battery is modeled by using multidimensional multiphysics modeling and simulated in a comsol. In this simulation, the effect of the thermal conductivity coefficient on the battery temperature, initial salt concentration in electrolyte and the rate of discharge... 

Epilepsy is a neurological disorder whose prevalence is estimated to be 1% of the world population. Electroencephalogram (EEG) is one of the best and convenient non-invasive tools used in diagnosis and analysis of this disease. Epileptic components extracted from EEG recordings are widely used in neuroscience in the diagnosis analysis like epilepsy source localization. However, epileptic components are often contaminated and covered with artifacts of physiological origin (baseline, EMG, ECG, EOG, etc.) or instrument noises (power supply, electrode, etc.). So, preprocessing and denoising is necessary for precise analysis of epilepsy EEG recording. Heretofore, several methods have been... 

In this study, integrated navigation systems that utilize velocity-matching algorithm and are used in automatic landing of Unmanned Aerial Vehicles (UAV) are investigated. At first, the accuracy of the navigation system in the landing phase is analyzed and the relationship between the accuracy of inertial sensors, flight parameters and the accuracy of the navigation system is derived analytically. Then, by integrating the dynamic model of the UAV and the inertial measurement unit, a new algorithm for navigation of fixed-wing UAVs is presented. The integration mechanism of the proposed algorithm is tightly coupled; hence, it is capable to eliminate the errors of UAV model and inertial system.... 

A high-Q tunable bandpass filtered amplifier structure is proposed which is based on N-path Q enhancement. Using Fourier series analysis, frequency response of an N-path filter and aliasing effect of this filter is achieved. This effect is caused by frequency translation to bandpass frequency as harmonic fold back (HFB). It is shown that using an additional N-path filter with the same clock frequency but different clock phase HFB is reduced. The conditions for fold back elimination are derived from Fourier series expansions for switched signals. In order to realize HFB reduction and increasing stop-band rejection and Q factor, an LNA associated with N-path filter is added to each of the... 

In this study pain level estimation using facial expression is investigated. To do this, there are two approaches, one approach is sequence level pain estimation and the other one is frame level pain estimation. In sequence level, after feature extraction from all frames of sequence, each sequence is represented by a fixed length feature vector, this feature vector is constructed by concatenating min, max and mean of frame features of that specific sequence, then KLPP is applied in order to reduce feature vector dimension and in the end a linear regression is implemented to predict the pain labels of the sequence. In the frame level, two approaches are introduced, the first one is based on... 

Nowadays dielectric substrates are widely used in Microwave Integrated Circuits. These substrates are made layer by layer in order to have favorable mechanical and thermal properties. The materials of the layers are usually different from each other and often each layer is a combination of different materials. This difference in material type and manufacturing method causes the substrate to have a different permitivity coefficient in two major directions, namely parallel and perpendicular direction. In fact, the electric field observes a different permitivity coefficient in each direction. This causes a problem in circuits that have both perpendicular and parallel electric field... 

Road roughness-induced vibrations are the main source of fatigue damage accumulation in vehicles. Hence, road surface profile modeling and simulation are of high importance when it comes to vehicle fatigue damage assessment. This research focuses on uncovering the statistical distributions that describe the characteristics of road loads that affect fatigue damage accumulation. Particle filtering is deployed to estimate the log-volatility of the road surface profile by assuming a random walk behavior for the hidden log-volatility. The skew-normal distribution with three parameters is fitted to the estimated log-volatility. The inferred parameters are used for synthesizing artificial road... 

Various applications of speech processing systems are gaining more and more attention. Performances of these systems are dramatically affected in presence of background noise. Attempts toward improving quality of degraded speech have emerged into filed of speech enhancement which is one of the interesting topics in speech processing domain. In this thesis various single channel speech enhancement methods are studied briefly. Statistical methods as one of the most successful methods are studied more deeply. These methods are divided into two categories of short-term modeling of speech and long-term modeling. The aim of this thesis is to improve the performance of long-term methods of... 

Today with increasing advancement of robotic technology, we witness the increment of robots role in humans’ life. One of the issues always present for robots is routing which may require locating their position. Most of these robots make use of sensors like gyroscope, accelerometer and GPS to estimate their position. But each of these sensors has their own short comings such as drift or being unavailable in certain environments. Fusion of inertial and vision sensor’s data can be used to reduce the impact of these errors. Considering the time consumption of image processing and accumulating error of inertial sensor, this combination can be very useful. This approach is also used in... 

Cardiovascular diseases stand as leading contributors to human mortality and disability, with heart muscle diseases, particularly acute and chronic failures, prevalent among them. While various diagnostic methods exist, an accurate, non-invasive, portable, easily accessible, and minimally disruptive approach for monitoring, requiring no frequent clinic visits, takes precedence. Early diagnosis and continuous fluid status monitoring through bioimpedance measurements of chest size are crucial in mitigating the mortality associated with these diseases. Utilizing bioimpedance as a non-invasive signal, this system facilitates ongoing vital parameter monitoring, treatment strategy optimization,... 

Structural best management practices (BMPs) are often used to mitigate the impact of storm water runoff on receiving waters. Vegetative filter strips (VFS) are an example of a structural BMP that has been used to treat storm water and highway runoff. In this study (the first in Iran), field-quality data were collected from a native VFS treating urban runoff in North of Tehran. At first field data were used to test the design concepts of the VFS treatment train and to modify and calibrate simulation model for evaluating the impact of physical factors such as slope, type of vegetation and impermeable surface on sediment removal then more field data were used to evaluate and modify the... 

Studies show that a large proportion of sent emails are spam. Spam is one of the major problems of e-mail users that result in wasting time and cost. To overcome this problem different ways are used, one of the best ways is detecting spam based on their contents. Separating legitimate e-mails and spam within their contents can be categorized as text classification. So machine-learning approaches are extremely applied in text classification, that machine-learning algorithms can be used for spam classification. However, in the majority of these algorithms, training phase is in a batch. Whereas using incremental learning algorithms is preferred in many applications, especially spam detections.... 

Excited jet flow has many physical and industrial applications, e.g. in aeroacoustics and the combustion instability. Analysis of this type of flow needs an accurate simulation of flow dynamics. This work presents the large eddy simulation of this type of flow. The numerical method used in the large eddy simulation must have low numerical dissipation and high order of accuracy. Compact methods which satisfy these requirements and have high resolution of frequency, are favorable ones for the large eddy simulation. A fourth-order compact finite volume method which had been developed in the MSc thesis of the author is extended and completed in the present work. This extension includes the... 

The extensive use of nonlinear loads such as motor drives and new generation of home appliances has caused a deterioration of power quality in power systems. The use of active power filters due to the fast variation of the loads has been recommended by power engineering. In this method, the harmonic profiles are controlled by applying active filters in a distribution feeder. Optimal placement of active filters in a distribution system due to the increase of harmonic generation loads has attracted researchers. However placement of each filter is the major concern that researchers face. In this paper, a new objective function is introduced to determine the optimal number and location of active... 

One of the security issues in database outsourcing scenario is the correctness of the query results. Correctness verification includes integrity, completeness and freshness of the results. Most of the proposed approaches for correctness verification impose high overhead on the components of the scenario which prevents the scenario to implemented in practical applications. In this thesis, we have proposed a probabilistic approach which imposes acceptable overhead for correctness verification of returned results of service provider. The approach uses the previous behavior of the service provider to calculate a trust value toward it which is used to adjust the imposed overhead. In other words,... 

Gene regulatory modeling in different species is one of the main aims of Bioinformatics. Regarding the limitations of the data available and the perspectives which should be taken into account for modeling such networks, proposed methods up to now have not yet been successful in yielding a comprehensive model. In one of the recent researches, the Gene regulation process is considered as a nonlinear dynamic stochastic process and described by state space equations. Afterwards, in order for the unknown parameters to be estimated, Extended Kalman Filtering is used. In this thesis, first of all, Gene complexes are taken into consideration instead of genes and afterwards, Extended Kalman... 

One of the most important parts of bacteria growth is specific concentration of nutrients added. Although the trace amount of heavy metals are required for bacteria growth, after a threshold concentration they may cause damage or kill the bacteria. Scientifically speaking, all these trace nutrients should be consider as a profitable source of energy for bacteria growth. There are several studies throughout pondering whether the advantages of using heavy metals, such as Zn, outweigh the drawbacks. It has been proven that heavy metals, especially, zinc salt, can improve microbial growth up to a specific threshold concentration. In this study, two upward submerged aerated reactors, which had 12... 

Recently, parametric excitation has been proposed and experimentally proven to provide micro gyroscopes with robustness to parameter variations and enhancement of sensitivity [L.A. Oropeza-Ramos, C.B. Burgner, K.L. Turner, Robust micro-rate sensor actuated by parametric resonance, Sensors and Actuators A: Physical, 152 (2009) 80-87].The first part of this thesis aims at investigating the nonlinear dynamics of MEMS vibratory gyroscopes with parametric excitation which can be represented by a minor variation of nonlinear Mathieu equation coupled to a Duffing oscillator. Our approach is based on analytical frequency response derivation via method of multiple time scales. Stability of responses,... 

Nowadays, recommender systems have become powerful tools that engage users in an online manner, over the Internet. Collaborative filtering (CF) is a well established method for building recommender systems and has been applied to several applications. While CF has its advantages,its use is hindered by challenges such as low accuracy for new users (newcomers). With the growth of online social networks, networkbased recommender systems emerged. These systems take advantage of the information available in social networks and the user’s past activity to recognize user behavior and recommend items that are more relevant to each user. One of the most important advantages of network-based... 

In this thesis, the orbit determination of Low Earth Orbits (LEO) using the integrated magnetometer and horizon sensor data has been investigated. Orbit determination is an essential part of a space mission. Not only the modeling, guidance, navigation and control errors may results in error in injecting the satellite into its nominal orbit, the environmental disturbances deviate the satellite from its predicted orbit and from an operational perspective most satellites need continuous orbit determination. Traditionally, ground based orbit determination is used which are non-autonomous and expensive and just can be used for specific times which the satellite can be observed from the ground...