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State Plane Analysis and Optimization of CLLC Resonant Converter for Bidirectional EV Charger
, Ph.D. Dissertation Sharif University of Technology ; Tahami, Farzad (Supervisor) ; Schanen, Jean-Luc (Supervisor)
Abstract
As more renewables step in, the ongoing change will be drastic for the electrical grid. The energy sector must find new ways to balance energy production and consumption. Electric vehicle (EV) batteries are by far the most cost-efficient form of energy storage since they require no additional investments in hardware. A bidirectional EV charger is a new technology that enables energy to be pushed back to the power grid and auxiliary loads from the battery. The electrical requirements of the EV charger are examined in detail to find an appropriate power electronics converter to meet all the requirements. The CLLC resonant converter is a promising candidate for high efficient, bidirectional...
An Integrated Formal Method for Specification and Verification of Component-Based Systems
, Ph.D. Dissertation Sharif University of Technology ; Movaghar Rahimabadi, Ali (Supervisor)
Abstract
This thesis presents an integrated formal method for modeling and model checking of component based computing systems. Both components and coordination subsystems are modeled by a variant of standard labeled transition systems called record transition systems. A record transition system is a labeled transition system whose transition labels are records. We use records to model the concurrency of input – output operations in the ports of the system. The concurrency of the executions with respect to common transition labels are modeled by standard parallel composition operator and also a new defined operator called join which is analogous to the join operator defined to compose constraint...
Estimating an Index of Iran’s Informal Economy in 1350-1386 With Concentration on the Impact of Government’s Intervention by EMIMIC Model (The Multiple Indicators-Multiple Causes Model and Error-Correction Model)
, M.Sc. Thesis Sharif University of Technology ; Nili, Masoud (Supervisor)
Abstract
In this research, an Index of Iran informal economy in response to the government interventions in credit, labor and product markets is stimated by EMIMIC model. To do this, first these interventions are measured using principal components analysis. In the model, the variables GDP and employment are used as indicators and taxation rates, government distortions in credit, labor and product markets, government expenditure, per capita income, unemployment and inflation as causes of the informal economy. We conclude these government interventions have affected Iran informal economy and their influence is more than indirect interventions influence such as taxation. The estimated index of Iran...
Rapid Assesment of Peak Floor Acceleration of Structures Using Transfer Functions
, M.Sc. Thesis Sharif University of Technology ; Karami Mohammadi, Reza (Supervisor)
Abstract
Peak Floor Acceleration (PFA) is a necessary requirement in Industrial Buildings for the design of equipment, piping, cable tray and ventilation duct supports. The seismic analysis of equipments needs the determination of PFA at the points where the equipments are fixed on the supporting structure. The classical spectral methods (SRSS, CQC) do not allow this determination which can be done in using the time integration method. This last approach needs to perform numerous calculations with various realizations of the seismic excitation. This thesis aims to present a method allowing calculating the response properties of a linear elastic shear building structure loaded by a transient...
Model Checking of Reo Specifications Using Automata Theorem
, M.Sc. Thesis Sharif University of Technology ; Movaghar Rahimabadi, Ali (Supervisor)
Abstract
This thesis represents the theoritical concepts used for the implementation of a model checking framework for Reo specifications. This framework is implemented as a model checking tool which is applied to some case studies. First we have studied the wide variety of sementic models represented for Reo. We claim that the semantic model based on Büchi automata of records is a suitable candidate to serve as the underlying model of a model checking tool. Reo language represents some special features like synchronization, fairness and context dependency. Reo semantic models are analyzed with respect to their expressivness of the mentioned features. Moreover, the way that Büchi automata of records...
Variation Trend Analysis of Groundwater Depth with Wavelet Neural Network, and Detection of Relationship Between Climate Variability and Groundwater Variation Depth with Wavelet Analysis (Ghorveh-Dehgolan plain)
, M.Sc. Thesis Sharif University of Technology ; Abrishamchi, Ahmad (Supervisor)
Abstract
Over time, human needs more groundwater to meet agricultural, industrial, and urban uses; so the study on factor affecting groundwater and groundwater level changes are important for water resource management. However, often forgotten is the fact that accurate and reliable predictions are based on a correct diagnose of the past. One of the questions here is how the climate has changed since the last. Such a question is largely related to detection. Purpose of detecting climate variability and climate change, identifying climate variability and trends in system and describe the factors causing these changes are. Without knowing and understanding these changes and fluctuations, we are not able...
Enhancing Model-Driven Methods For Composition-Based Software Development
, M.Sc. Thesis Sharif University of Technology ; Ramsin, Raman (Supervisor)
Abstract
Using models to design systems has always had a vital role in engineering. Model Driven Development (MDD), as used in software engineering, uses models, modeling methods, and model transformation techniques as bases for automating the software development process. To this aim, MDD focuses on models and automatic model transformation to provide techniques for designing, understanding and maintaining models more easily. In order to achieve MDD goals, the Model Driven Architecture (MDA) was proposed by Object Management Group as a standard framework for MDD. On the other hand, Composition-Based Development (spanning Component-Based Development and Service-Oriented Development) has been...
Modeling of Damages such as Crack, Inclusions and Areas with Variable Properties in Composite and Metal Structures and then Prediction and Extension of their Life
, M.Sc. Thesis Sharif University of Technology ; Abedian, Ali (Supervisor)
Abstract
Nowadays, some of the major problems of the airplane industry is that airplanes’ fleet are approaching to the end of their defined life, inability to buy new planes and obtaining aircraft’s parts for repairing process. Therefore, in order to increase the life of the aging aircrafts, some essential process such as modeling processes, identify principal structure elements to strengthen and repair them should be done to all these airplanes, all these processes refer as aging process. Aging programs initiated in some countries, such as America, Australia, Britain and Canada from about thirty-five years ago, technological approaches inventing new ways to start repairing worn metallic structures...
Blind Speech Separation using Sparse Component Analysis
, M.Sc. Thesis Sharif University of Technology ; Babaei-Zadeh, Masoud (Supervisor)
Abstract
Separation of speech signals has many applications. For example, it is used human-machine communications. This problem can be divided into three categories: overdetermined, determined and underdetermined. If the number of mixtures is greater than the number of sources, the problem is called overdetermined; if it is equal to the number of sources, the problem is called determined and if it is less than the number of sources that problem is called underdetermined. This MS thesis studies the undertermined case. Moreover, speech signals are sparse in time-frequency domain, meaning that in each time-frequency point, usually only one source is active. So, for separatig the speech signals,the...
The Effect of Rocking Foundation Input Motion on Inelastic Behavior of Multi Degree of Freedom Structures
, M.Sc. Thesis Sharif University of Technology ; Ghannad, Mohammad Ali (Supervisor)
Abstract
Non rigidity of the soil beneath the structure, alters elastic and inelastic response of it. This effect is caused by the soil-structure interaction. The effect of soil-structure interaction is studied in two parts, Kinematic interaction and inertial interaction. Among these, kinematic interaction effects are often assumed to be negligible so that even in existing regulations it has been ignored. While the kinematic part of soil-structure interaction effect could produce a rocking input motion that might be important. In recent years, according to expanding usage of performance based design philosophy, researches on inelastic behavior of the soil-structure systems has been done which is...
Fixed-Mix Rules in an Evolutionary Market Using a Factor Model for Dividends
, M.Sc. Thesis Sharif University of Technology ; Zamani, Shiva (Supervisor)
Abstract
In this thesis, we simulate the competition between some investment strategies based on dividends with each other and with mean-variance strategy (Markowitz) in an evolutionary finance framework. We perform simulations by two different approaches. In the first one, we use real dividend data and, in the second one we use dividends that are generated according to a dividend factor model. The dividend factor model which relates the dividends to the macro-economic factors is estimated from data using principal component analysis. Our simulations show that in this competition, the evolutionary portfolio rule will eventually hold the total market wealth. According to this simple rule the portfolio...
Redundancy Allocation Problem in Systems with Dependent Components
, M.Sc. Thesis Sharif University of Technology ; AkhavanNiaki, Mohammad Taghi (Supervisor)
Abstract
Consider a serie_parallel system in which the lifetimes of parallel components in series subsystems are independent. But, the lifetimes of series subsystems are dependent due to their similar components. In this thesis, the redundancy allocation problem is studied for this system in order to maximize system reliability. A model is developed and a genetic algorithm is utilized to find near-optimum solution
Identification of Conductive Particles in Transformer Oil Model using Partial Discharge Signal
, M.Sc. Thesis Sharif University of Technology ; Vakilian, Mehdi (Supervisor)
Abstract
Transformer are one of the most important equipment in transmission and distribution network. Transformer unplanned outage have severe impacts on the continuity of power system operation and is also an irreparable economic harm to power network operators. To improve the reliability of transformers and to achieve an optimum operation cost, online condition monitoring is inevitbale. Information about the quality of the transformer insulation system is known as the best parameter to be monitored in transformer. Since partiale discharge (PD) signals are initiated long before the beginning of a severe damage, monitoring and its evaluation can be employed to warn the operator. Data mining on the...
Study the Effects of Components Ratio on Microstructure and Mechanical Properties of Polyethylene Ternary Blend (HDPE/LLDPE/LDPE)
, M.Sc. Thesis Sharif University of Technology ; Bagheri, Reza (Supervisor)
Abstract
Melt blending of polymers is a rather cheap and easy approach for obtaining new set of properties compared to synthesizing new polymeric materials. For the same reason, binary and ternary polyethylene blends are made to provide added value for different applications. Polyethylene blends are commonly composed of high density polyethylene (HDPE), low density polyethylene (LDPE) and linear low density polyethylene (LLDPE). Although the Mechanical and physical properties of polyethylene binary blends have been studied extensively, microstructure and mechanical properties of polyethylene ternary blends have been the subject of very few studies. In this work, samples with 40-60 Wt. % HDPE and...
Determining Location and Estimating Severity of Damage Using Sensitivities of Principal Components of Frequency Response Functions
, M.Sc. Thesis Sharif University of Technology ; Rahimzadeh Rofouei, Fayyaz (Supervisor) ; Esfandiari, Akbar (Supervisor)
Abstract
Principal component analysis (PCA) is a conventional tool for dynamic system analysis. In this paper, a new damage diagnosis method is presented based on sensitivities of principal components obtained from PCA of Frequency response functions (FRFs). Damage identification, determination of its location and estimation of the damage severity are conducted by an innovative well established sensitivity relation of PCA results. Then, sensitivity matrix is obtained by using measured frequency of damaged structure, and comparison of PCA of the intact structure with PCA from FRFs which are measured at sensors locations. Damage location and its severity are calculated by model updating procedure. This...
A New Model for Reliability Optimization of Series-parallel Systems Using Mixed Redundancy Strategy
, M.Sc. Thesis Sharif University of Technology ; Eshraghniaye Jahromi, Abdolhamid (Supervisor)
Abstract
In current societies, reliability is an important and fundamental factor in designing and manufacturing products and it cannot be ignored anyway; because sometimes malfunction and failure in a system can cause severe financial losses and health issues. In the field of optimizing reliability by redundancy allocation, one of the structures that has drawn many researchers attention is series-parallel structure. In the models proposed for reliability optimization in series-parallel systems, there is a restricting assumption which all components of a sub-system have to be homogeneous. In this thesis, new models are presented which enable components of a sub-system be non-homogeneous. Modeling is...
Analysis of Designed Experiments with Multichannel Profiles Response Variable
, M.Sc. Thesis Sharif University of Technology ; Niaki, Akhavan (Supervisor)
Abstract
The purpose of this research is analyzing designed experiments which their response variable is in form of multichannel profiles. For this purpose, a number of experiments with multichannel profile response variable designed at first. Then by random effect model, output data calculated. Experiments output data dimension reduced using principal component analysis and its extensions. After that, regression analysis used to analyze results of dimensionality reduction data in order to estimate coefficients of potentially effective variables in response. At the end, coefficients of effective variables classified with a hierarchical classification method in order to discover change and its root...
Modeling and Structural Health Monitoring of 5 MW Wind Turbine Based on Moving Principal Component Analysis
, M.Sc. Thesis Sharif University of Technology ; Abedian, Ali (Supervisor)
Abstract
Nowadays, the structural health monitoring is considered as an essential element in improving the performance of the structures. The role and importance of the issues in this area have been reached to the point that different ideas and policies are developed for the safety margin over the useful life of the structures. To analyze more accurately, a real model of a turbine blade is required. This issue would be taken into more consideration when the scale of the turbine gets larger. Changing of the design philosophies over time results in effective changes in the design process and maintenance procedures. Any single of these inspections has different importance according to users' demands. In...
Design and Develop of a new Multivariate Control Chart for Image based Process Control based on Principal Component Analysis for Multivariate non Normal Distribution
, M.Sc. Thesis Sharif University of Technology ; Akhavan Niaki, Taghi (Supervisor)
Abstract
Control charts have always had an undeniable role in Statistical Control of processes in many fields. The growth of quality characteristics to be monitored, has led to the vast utilization of multivariate control charts. These variables are characterized by relatively high correlation between them. The complicated structure of measured variables has lessened the reliability of conventional control charts. Projection methods have been developed to address the problem of high correlated variables by transforming the correlated variables to an uncorrelated set of variables. Among them, Principal Component Analysis based control charts have been widely used to overcome the problem of correlated...
Adaptive Estimation of Components of a Three-Phase Signal Polluted with Sinusoidal Disturbance
, M.Sc. Thesis Sharif University of Technology ; Karimi, Houshang (Supervisor)
Abstract
This thesis proposes a new method for estimation of parameters of a multi-component signal. The signal is composed of several sinusoidal components whose frequencies and magnitudes are unknown. Moreover, the signal is polluted with white noise. The estimated parameters are frequency, amplitude, and phase-angle of each component. The proposed method is able to adaptively decompose the multi-component signal into its constituting sinusoidal components. The core unit of the proposed method comprises an adaptive band-pass and an adaptive notch filter. The proposed method consists of parallel connection of several core units. The band pass filter rejects all components except the one whose...