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Optimal Design & Fabrication of a Non-Flat Sun Sensor Array With Large Field of View
, Ph.D. Dissertation Sharif University of Technology ; Durali, Mohammad (Supervisor) ; Jalali, Mir Abbas (Supervisor)
Abstract
Modern sensors consist of arrays of detectors specially arranged to enhance precision, capabilities, and field of view (FOV). Sensor arrays can have multiple functionalities such as the simultaneous detection of position and motion. We use a linear sensor model and develop an optimization method to design an array of photodiodes. Our objective function minimizes bias and variance estimations. We introduce a maximum likelihood technique to approximate and determine the bias caused by measurement errors, and verify our theory by statistically complete simulations. We apply our theory to design an optimal sun sensor. The sensor has a predefined conical FOV, and its accuracy is controlled by a...
Robust Orientation Estimation Using Imu and Online Machine Learning Based Calibration in the Presence of Distortions
, M.Sc. Thesis Sharif University of Technology ; Khodaygan, Saeed (Supervisor)
Abstract
In this project an optimized and robust orientation estimation method using IMU and magnetic sensors is presented. Magnetic distortion effects in orientation estimation is also one of the main purposes. Proposed sensor fusion algorithm is based on a complementary filter which provides a quaternion estimation as the algebraic solution of a system from inertial/magnetic observations. To develop the basic sensor fusion algorithm some procedures including a simple calculation to deal better with non-gravitational accelerations, decrease the effect of magnetometer in the presence of distortions and online gyroscope bias estimation is added. Also, a method for classification the different types of...
A Numerical-Analytical Solution for Determining the In-situ Horizontal Stress according to the CPT Measurements
, Ph.D. Dissertation Sharif University of Technology ; Ahmadi, Mohammad Mehdi (Supervisor)
Abstract
Separation of the effects of the initial horizontal stress and relative density on the cone tip resistance in the sandy soils has been a complicated issue for many years. On the other hand, there is no reliable method for determining the in-situ horizontal effective stress based on the piezocone measurements in the cohesive soils, and the empirical correlations suggested in the literature produce no more than a rough estimation.Considering the aforesaid issues, an attempt is made in this thesis to provide a new innovative solution for determining the in-situ horizontal (effective) stress in the sandy and clayey soils according to the CPT measurements. In this regard, at first, numerical...
Integrated Orbit and Attitude Parameter Determination of a Satellite Using Hybrid Nonlinear Filters
, Ph.D. Dissertation Sharif University of Technology ; Pourtakdoust, Hossein (Supervisor)
Abstract
Rapid growth of space traffic and small satellite systems for current and future space missions have generated new enhanced performance requirements for navigation subsystem. As such, the navigation subsystem is considered as a vital part of all active satellite systems that effectively influences their successful missions. In this regard, the present work is dedicated on the subject of autonomous satellite navigation utilizing nonlinear filters, for which some laboratory experimentations have also been implemented. Generally, advanced orbit and attitude estimation algorithms can effectively compensate for the effect of low cost hardware and sensor packs utilized in microsatellites. In...
Modeling and Calibrating the Soil Moisture and Discharge with VIC Model and SMAP Satellite Data, Saghez Station, Zarinehrood River Basin
, M.Sc. Thesis Sharif University of Technology ; Tajrishi, Masoud (Supervisor) ; Jalilvand, Ehsan (Co-Supervisor)
Abstract
In this thesis we evaluate VIC hydrological model’s simulated soil moisture and discharge at Saghez synoptic station, located at ZarinehRood sub basin, Urmia Lake basin in three time periods to overcome observational and satellite data scarcity in the basin. All the input files for this macro scale semi-distributed model chose from satellite data. With a multi-objective calibration algorithm called NSGA-II and utilizing Nash-Sutcliffe (NSE) and R2 as objective functions for discharge calibration and correlation coefficient and RMSE for soil calibration, the model results evaluated. As where as we didn’t have access to observational soil moisture data, we utilized SMAP satellite soil moisture...
Determination of Lateral Pressure of Sandy Soil Using Results of Calibration of Cone Penetration Test
, M.Sc. Thesis Sharif University of Technology ; Ahmadi, Mohammad Mehdi (Supervisor)
Abstract
Cone Penetration Test (CPT) is one of the major in-situ tests used around the world. Obtaining undisturbed samples from sands is generally very difficult and expensive, and in some cases impractical. A good interpretation of CPT results can provide important soil parameters, and therefore the need for undisturbed sampling may be reduced. Using Calibration Chambers, a soil with predefined parameters is tested by cone penetrometer and some relationships are developed between CPT results and soil parameters. Using these relationships, in-situ results are interpreted. CPT results can be used to evaluate different aspects: soil stratification, geoenvironmental characteristics, stress state and...
Radar Directional Finding by Interferometric Method in 2-18 GHzBW
, M.Sc. Thesis Sharif University of Technology ; Farzane, Frohar (Supervisor) ; Pezeshk, Amir Mansor (Co-Advisor)
Abstract
One of the important jobs of ESM and Elint receiver is to find the direction of arrival of the targets. Also DOA estimation has applications in guiding missiles and jammers location, position finding using of multiple DF systems which are placed in different locations is the most important use of this type of system.
A DF system has multiple parts: receiver, algorithm and arrays of antennas.
Amplitude comparison algorithms are more simple but on the other hand phase comparison algorithms prepare more accurate estimation. In this thesis these algorithms are simulated and to each other. And it will be concluded that, in the application being test, the "MUSIC" algorithm is the best....
A DF system has multiple parts: receiver, algorithm and arrays of antennas.
Amplitude comparison algorithms are more simple but on the other hand phase comparison algorithms prepare more accurate estimation. In this thesis these algorithms are simulated and to each other. And it will be concluded that, in the application being test, the "MUSIC" algorithm is the best....
Design and Fabrication of Weigh in Motion System for Railway Vehicles
, M.Sc. Thesis Sharif University of Technology ; Saadat Foumani, Mahmud (Supervisor)
Abstract
Railroads should be well maintained for safe and efficient operation. The most important reason for the failure of railways is overload and asymmetric load on them. Also, the proper interval for repairs should be adjusted to fit the load crossed over. In order to carry out all these tasks, a constant observation of the weight on the rails must take place. Current dynamic weighing systems are costly. In addition, the installation of these systems is time-consuming and causes permanent damage to the rails. On the other hand, some of the cheaper models of weighing systems require full stop and static weighing, which practically does not work at all, especially on busy rails due to delays. The...
Calibration of PTZ Cameras from Multiview Soccer Match Videos
, M.Sc. Thesis Sharif University of Technology ; Kasaei, Shohreh (Supervisor)
Abstract
Camera calibration in sport videos has applications such as sport video analysis, insertion of virtual graphical elements, and 3D reconstruction. Our goal in this research is to fully calibrate cameras in soccer match videos. By calibration parameters, we mean the internal and the external camera parameters. We can have a mapping from world coordinates to image coordinates if we have all the calibration parameters. The cameras used in this research are stationary pan-tilt-zoom cameras. The main challenges in camera calibration are noise, blur, bad lighting conditions, lack of useful information image,fast movement of camera and radial distortion. In addition, as another challenge, we assume...
Radio Receiver Design for Cognitive Radio in The UHF Band
, M.Sc. Thesis Sharif University of Technology ; Fotowat Ahmady, Ali (Supervisor)
Abstract
With the ever-increasing communication need for propagating signals in authorized empty bands, the goal of this thesis is based on finding these unused bands and using them,which called Cognitive Radio. In this project, design and implementation of radio frequency building blocks of a receiver in the UHF band (400 to 800 MHz) is performed. In this project, however, the radio frequency building blocks include low noise amplifier, high-frequency quadrature mixers, high-frequency oscillators, tunable low-pass filter,band select filter,phase-locked loop and synthesizer, all of which are introduced, examined and implemented. Moreover, a new method which mitigates the speed limitation is verified....
Agricultural Economics model of Urmia Lake Basin
, M.Sc. Thesis Sharif University of Technology ; Vesal, Mohammad (Supervisor) ; Fatemi Ardestani, Farshad (Supervisor)
Abstract
This Thesis was an effort to write and quantify an agricultural economic model for Urmia Lake Basin and evaluate the change in water consumption in reaction to a policy change. Aggregated form of the data gathered from 33 counties located in Urmia Lake Basin was used in this research. This data includes the quantity used of each input and their costs, in addition to crop yield and their selling price. In our model, the representative farmer takes into account the price of various inputs, crops and the condition of the farm and its limitations and decides on the profit-maximizing crop pattern. In this model, water is one of the most important inputs and its price and availability, effects the...
Low-dimensional POD Simulation of Unsteady Flow around Bodies with Arbitrary Shapes
, Ph.D. Dissertation Sharif University of Technology ; Tayyebi Rahni, Mohammad (Supervisor)
Abstract
The aim of this research was an investigation, development, and application of low- dimensional proper orthogonal decomposition (POD) method for simulation of unsteady flow around bodies. Since analytical methods have low accuracy and limitations and also experimental methods have other problems, researchers usually use computational approaches, which mostly do not have acceptable efficiency and speeds of computations (especially in 3-D unsteady flows). On the other hand, the idea of application of reduced order modelling, which orginally comes from control theories and structural analysis, have attracted many researchers in recent years. In this research, we also used POD for reduced order...
Create an Algorithm for Designing of Button-BPM and Striplines in a Synchrotron
, M.Sc. Thesis Sharif University of Technology ; Samadfam, Mohammad (Supervisor) ; Mohammadzadeh, Mohammad (Co-Advisor)
Abstract
Beam diagnostics is an essential constituent of any accelerator. The position information of the electron beam is obtained by a set of Beam Position Monitors (BPMs), which in addition to determining the position, are used to derive information concerning lattice functions and beam dynamics. To design of Button Beam Position Monitor(BPM) for a Synchrotron Light Source, to get beam stabilities on submicron levels, preliminary studies were done to have optimal design. We present an algorithem which caculate all required parameteres for different design of button BPMs. To calculate induced charge and voltage on each button, Poisson's equation has been solved by Green method. For sensivity...
Predictive Equations for Shear Link Modeling Toward Collapse
, M.Sc. Thesis Sharif University of Technology ; Mohtasham Dolatshahi, Kiarash (Supervisor)
Abstract
In this paper the predictive equations for collapse assessment of shear links used in eccentric braced frames are developed. An extensive database including results of over 70 cyclic tests on steel wide flange shear links is collected and the structural parameters governing the hysteresis behavior are calibrated using a simplified numerical model. The methodology of calibration is to minimize the discrepancy between the experimental hysteresis loops and the corresponding numerical results using Particle Swarm Optimization (PSO) algorithm. The objective function of PSO algorithm is minimized by iterating parameters that govern the hysteresis behavior of the numerical model. Stepwise...
Experimental Study of the Effect of Wing Flapping on the Aerodynamic Performance of Tail and the Stability of a Flapping Wing Air Vehicle
, M.Sc. Thesis Sharif University of Technology ; Pourtakdoust, Hossein (Supervisor) ; Kiani, Maryam (Co-Supervisor)
Abstract
In adaptation with nature, Flapping Wing Arial Robots (FWARs) are flying vehicles that use wing flapping motion to produce lift and thrust forces simultaneously. Wing oscillating motion of FWARs in turn creates an unsteady and turbulent flow field around them that makes their aerodynamic modeling and analysis a complex and formidable task. As a result, experimental aerodynamic investigation of FWARs has been the focus of many researchers in the last few years. Inspired by nature, Bird-like FWARs utilize a tail as an augmented aerodynamic surface during their flight motion. In turn the tail aerodynamics that in general plays an important role in flight stability and control is adversely...
Reliability-based Evaluation and Calibration of Load Combinations for the Design of Steel Building Structures of Iran
, M.Sc. Thesis Sharif University of Technology ; Mahsuli, Mojtaba (Supervisor) ; Ghasemi, Hooman ($item.subfieldsMap.e)
Abstract
The objective of this thesis is to evaluate and calibrate design load combinations of steel building structures of Iran based on the reliability theory. The importance of this research stems from recognition that the design load combinations for steel structures in Section 6 of the National Building Code of Iran have been completely adopted from the ASCE/SEI 7-10 standard, whereas the factors that affect these load combinations differ in Iran from those of the United States. Examples are the difference in the construction industry economy, lower quality of here and the differences in probability distributions for the specifications of steel. Hence, the load combinations need to be calibrated...
3D Reconstruction and Extrinsic Parameters Calibration of Non-Overlapping Cameras
, M.Sc. Thesis Sharif University of Technology ; Razvan, Mohammad Reza (Supervisor) ; Moghadasi, Reza (Co-Supervisor) ; Kamali Tabrizi, Mostafa (Co-Supervisor)
Abstract
Non-overlapping Cameras in multi-camera systems have become prevalent in robotics and computer vision research; therefore, it is possible to cover the wide field of view, and researches have been done for computing extrinsic parameters of cameras. These cameras do not have any overlap in their views, so obtaining the corresponding point in their images is somehow impossible. Light and shadow geometry is analogous to Structure from Motion problem. In this thesis,we study Structure from Motion problem and have tried to propose an approach for estimating extrinsic parameters of non-overlapping cameras in Multi-camera systems. We formulate the problem by using light and shadow geometry and...
Modification of Evolving Factor Analysis and Multivariate Curve Resolution Methods and Using their Applications in Analysis of Medicinal Plants Essential Oils
, Ph.D. Dissertation Sharif University of Technology ; Jalali-Heravi, Mehdi (Supervisor) ; Ghassempour, Alireza (Co-Advisor)
Abstract
Factor analysis based methods are one of the applied methods in the Chemometrics. In this regard, some modifications on one of the factor analysis based method named fixed size moving window evolving factor analysis were done and two new methods named variable size moving window evolving factor analysis and preselected variable size moving window evolving factor analysis were introduced. The performance of the new introduced methods were examined and compared by the fixed size moving window evolving factor analysis.
Pure variable selection methods are useful for curve resolution methods which need to define an initial estimate from chromatographic profile or spectra. In this aspect the...
Pure variable selection methods are useful for curve resolution methods which need to define an initial estimate from chromatographic profile or spectra. In this aspect the...
Design of a High Speed Time-Interleaved SAR ADC
, M.Sc. Thesis Sharif University of Technology ; Sharifkhani, Mohammad (Supervisor) ; Fotowat Ahmadi, Ali (Supervisor)
Abstract
The digital nature of Successive Approximation Register (SAR) Analog to Digital Converter (ADC) suits them for the new technologies with small gate length and low power applications. Applications such as ultra-wideband receivers, satellite receivers and high speed serial links demand medium resolution and high sampling rate ADCs. Due to binary search algorithm speed limitations, SAR ADCs belong to low to moderate speed category. In this thesis time-interleaving and two-bit-per-cycle technique are used in order to increase SAR ADC sampling rate. These techniques are both sensitive to offset and if the comparators used in SAR ADC have different offsets signal-to-noise-and-distortion will be...
Extracting Homography Matrix to Determine 3D Position of Soccer Players
, Ph.D. Dissertation Sharif University of Technology ; Kasaei, Shohreh (Supervisor)
Abstract
Determination of the position of an object in the 3D world is one of the most basic preprocessing steps in the field of computer vision. It is used in many practical applications such as video surveillance, human action analysis, and human-computer interaction. For this determination, calibrated cameras are usually used for which the internal and external camera parameters are already known. But, in some real-life applications, a pre-access to the camera is not possible. This thesis studies the homography matrix extraction for determination of the position of soccer players. The pan-tilt-zoom (PTZ) cameras are used. (For a stationary camera, a Homography matrix is obtained once.) To...