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marzban--mohammad
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Positioning and tracking control of an amphibious single wheel robot
, Article 2008 ASME International Mechanical Engineering Congress and Exposition, IMECE 2008, Boston, MA, 31 October 2008 through 6 November 2008 ; Volume 11 , 2009 , Pages 545-551 ; 9780791848722 (ISBN) ; Alizadeh, D ; Sharif University of Technology
2009
Abstract
Amphibious single wheel robot consists of a sharp-edged wheel actuated by a spinning flywheel for steering and a drive motor for propulsion. The spinning flywheel acts as a gyroscope to stabilize the robot and also can be tilted to achieve steering. In this paper, the kinematics of a single wheel robot in water, Gyrover, is analyzed and then a simple mechanism for driving it is proposed. In previous studies, Lagrange approach is used for hydrodynamic modeling of the robot. A nonlinear position controller is designed to bring the robot to any desired position. Based on the designed controller, a tracking controller is augmented to the robot. For simplicity the added mass effect has been...
Stability control of an Amphibious single wheel robot
, Article ASME International Mechanical Engineering Congress and Exposition, IMECE 2007, Seattle, WA, 11 November 2007 through 15 November 2007 ; Volume 9 PART B , 2008 , Pages 1465-1472 ; 0791843033 (ISBN); 9780791843031 (ISBN) ; Alasty, A ; Sharif University of Technology
2008
Abstract
Single wheel robots are typically those kinds of robots which contain all the necessary mechanizations, namely the stabilization and driving mechanizations, within a shell-liked housing appearing analogous to a wheel. These robots have proved to be useful in various fields of industry due to their advantages of giving high instant acceleration and maintaining high cruise speeds for considerable amount of time in addition to being compact and small. It is a sharp-edged wheel actuated by a spinning flywheel for steering and a drive motor for propulsion. The spinning flywheel acts as a gyroscope to stabilize the robot and it can be tilted to achieve steering. In this paper first the kinematics...
Dynamic anlysis of an amphibious single wheel robot part1: Moving in straight path
, Article 31st Mechanisms and Robotics Conference, presented at - 2007 ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, IDETC/CIE2007, Las Vegas, NV, 4 September 2007 through 7 September 2007 ; Volume 8 PART B , 2008 , Pages 927-932 ; 0791848027 (ISBN); 9780791848029 (ISBN); 0791848094 (ISBN); 9780791848098 (ISBN) ; Alasty, A ; Sharif University of Technology
2008
Abstract
A single wheel, gyroscopically stabilized robot is a sharpedged wheel actuated by a spinning flywheel for steering and a drive motor for propulsion. The spinning flywheel acts as a gyroscope to stabilize the robot and it can be tilted to achieve steering. In this paper first the kinematics of a single wheel robot, like Gyrover, in water is considered and then a simple mechanism for its movement in water is proposed. After hydrodynamic analysis of the robot a complete dynamics model is designed with Lagrange energy method. The only simplification used here is neglecting the added mass effect in hydrodynamic analysis. This complete model can be used for examining the behavior of the robot in...
Optimization and Implementation of Detection and Control Algorithms in an APF
, M.Sc. Thesis Sharif University of Technology ; Mokhtari, Hossein (Supervisor)
Abstract
Today, with the increasing use of non-linear loads in the power grid, power quality problems such as current harmonics, unbalance and reactive power have intensified. It is common to use active power filters to solve these problems. In order to justify the use of active filter, two approaches can be adopted. On the one hand, by increasing the active filter capability such as simultaneous harmonic compensation, umbalance and reactive power by one device, the filter capabilities increased. On the other hand, it reduced the final cost of the active filter. In this research, firstly, a comprehensive hardware structure for various compensation applications is presented. This is done with the aim...
Estimation of Springback in Sheet Metal Stamping Using Inverse Finite Element Method
, M.Sc. Thesis Sharif University of Technology ; Asempour, Ahmad (Supervisor)
Abstract
This work presents a quick method in estimation of spring back effect in sheet metal forming. In this method, the so called Inverse Finite Element Method (IFEM) has been adopted for compution of strains and also blank shape. Although the of element used is membrane, the effect of bending/ unbendiing is considered by addition of some extra forces as the bending forces to the nodal forces. The results of strain distribution obtained by IFEM are applied to another algorithm developed for computation of the spring back . this algorithm has been developed for the sections with plane starin assumption. Therefore, spring back of longitudinal parts, can be estimated by this method in a short time....
Wideband and multi-band frequency selective surfaces for microwave shielding
, Article 29th Iranian Conference on Electrical Engineering, ICEE 2021, 18 May 2021 through 20 May 2021 ; 2021 , Pages 836-842 ; 9781665433655 (ISBN) ; Alighanbari, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
Monolayer band-reject frequency selective surfaces (FSS) based on curved coupled microstrip line (CCML) resonators are proposed. Each unit cell comprises a single- or multi-loop CCML resonator, featuring single-wideband or multi-band resonance, respectively. Design guidelines for achieving various responses are demonstrated and it is shown there is a great flexibility attaining desired frequency responses versus structural parameters. For instance, it is shown that the entire microwave X-band may be rejected, using a simple single-loop structure. The FSS is particularly useful for protecting buildings against parasitic microwave signals. A visual transparency factor for the FSS, when regular...
Design and Simulation of all Optical/hybrid Neural Networks
, M.Sc. Thesis Sharif University of Technology ; Khavasi, Amin (Supervisor)
Abstract
Analog computing has emerged as a promising candidate for Neural networks' implementation due to its high Interconnectivity, high bandwidth, parallel computing, high-speed processing, and low power consumption. Artificial Neural Networks have a wide range of applications; however, the Implementation of complicated Neural Networks on traditional computers would encounter two fundamental obstacles: limited processing speed and non-optimal energy consumption. This thesis's primary focus is on designing and simulating a whole-passive planar Optical neural network(ONN) based on silicon photonics technology. Firstly, the concept of ONN is studied using some lately proposed work. The device is...
A new method for the solution of hybrid analog digital beamforming problems
, Article Optimal Control Applications and Methods ; Volume 41, Issue 5 , 2020 , Pages 1735-1748 ; Reza Marzban, H ; Rastegari, M ; Sharif University of Technology
John Wiley and Sons Ltd
2020
Abstract
By going to millimeter wave (mmWave) we can use large scale MIMO due to short mmWave wavelength to overcome path loss by using beamforming to focus power of signal to the receiver. System structure of mmWave band is different with conventional MIMO because of large scale MIMO which is leading to use many RF-chains. For this reason Hybrid structure have been proposed for large Scale MIMO. By going to Hybrid structure a new issue has been created with phase shifter constraint. In this paper we propose a novel solution to make a hybrid precoding and combing to reach high spectral efficiency. Our problem includes a maximizing Frobenius norm of multiplying five complex matrices. As constraints,...
Effect of mozart music on hippocampal content of BDNF in postnatal rats
, Article Basic and Clinical Neuroscience ; Volume 2, Issue 3 , 2011 , Pages 21-26 ; 2008126X (ISSN) ; Shahbazi, A ; Tondar, M ; Soleimani, M ; Bakhshayesh, M ; Moshkforoush, A ; Sadati, M ; Zendehrood, S. A ; Joghataei, M. T ; Sharif University of Technology
2011
Abstract
Introduction: It has shown that listening to Mozart music can potentiate spatial tasks in human; and reduce seizure attacks in epileptic patients. A few studies have reported the effects of prenatal plus postpartum exposure of mice to the Mozart music on brain-drived neurotrophic factor (BDNF) in the hippocampus. Here we investigated the effect of postpartum exposure to The Mozart music on BDNF concentration in the hippocampus of rat. Methods: Thirty male one day old newborn Wistar rats divided randomly in two equal experimental and control groups. Experimental group exposed to slow rhythm Mozart music (Mozart Sonata for two pianos KV 448, 6 hour per day; sound pressure levels, between 80...
Construction of an Experimental Device for Foaming Agent and an Experimental Study of the Properties of Foaming Agent
, M.Sc. Thesis Sharif University of Technology ; Bazargan, Mohammad (Supervisor)
Abstract
The primary purpose of acidizing operations in the oil and gas industry is to enhance hydrocarbon production. Acidizing has been a common and conventional method for years, especially when production engineers face issues like declining reservoir pressure leading to reduced production rates. Initially, the treatment solution is referred to as matrix acidizing. In acidizing operations, different additives are combined with the acid to control its behavior in the reservoir. These additives may include iron control agents, corrosion inhibitors, friction reducers, and more. Incompatibility among these additives, the acid, and reservoir fluids can lead to severe damage to the reservoir....
Numerical Analysis of An Annular Gas Turbine Combustor
, M.Sc. Thesis Sharif University of Technology ; Farshchi, Mohammad (Supervisor)
Abstract
The goal of this research is the simulation of the annular combustion chamber of the turbine engine utilized by liquid fuel. The achievement to this goal will lead to create numerical tools for parametric study, analysis and combustion chamber designing.For this reason simple geometry has been considered. This simplicity of geometry causes to facilitate in parametric study and decrease in saving time for modeling and meshing. This combustion chamber is a simplified model of engine CF6. In recent study, the k – ε realizable model has been used for turbulence modeling. For non-adiabatic condition, chemical reaction is dissolved by utilizing probability density function along with laminar...
A misbehavior‐tolerant multipath routing protocol for wireless Ad hoc networks [electronic resource]
, Article International Journal of Research in Wireless Systems (IJRWS) ; Vol. 2, Issue 9, pp. , Sep. 2013 ; Pakravan, Mohammad Reza ; Aref, Mohammad Reza ; Sharif University of Technology
Abstract
Secure routing is a major key to service maintenance in ad hoc networks. Ad hoc nature exposes the network to several types of node misbehavior or attacks. As a result of the resource limitations in such networks nodes may have a tendency to behave selfishly. Selfish behavior can have drastic impacts on network performance. We have proposed a Misbehavior-Tolerant Multipath Routing protocol (MTMR) which detects and punishes all types of misbehavior such as selfish behavior, wormhole, sinkhole and grey-hole attacks. The protocol utilizes a proactive approach to enforce cooperation. In addition, it uses a novel data redirection method to mitigate the impact of node misbehavior on network...
Theoretical and Experimental Study to Conversion of AUC to UO2 by Microwave Heating
, Ph.D. Dissertation Sharif University of Technology ; Otukesh, Mohammad (Supervisor) ; Ghannadi Maragheh, Mohammad (Co-Advisor) ; Ghasemi, Mohammad Reza (Co-Advisor)Estimating Possible Effects of Subsidies in Competition and Development of Fixed Broadband Internet
, M.Sc. Thesis Sharif University of Technology ; Vesal, Mohammad (Supervisor) ; Rahmati, Mohammad Hossein (Supervisor)
Abstract
In this work, the dynamic competition between firms providing internet services is studied. The framework is Markov equilibrium whereby structural parameters are obtained using two-step estimations, allowing for analyzing the situation in case of subsidies for service upgrade. The results show that such subsidy has little effect on the number of firms while increasing the number of fast firms
SAR Imaging Using the TomoSAR Technique to Resolve Multiple Scatterers
, M.Sc. Thesis Sharif University of Technology ; Bastani, Mohammad Hassan (Supervisor) ; Karbasi, Mohammad (Co-Supervisor)
Abstract
During the last few years, the study of urban environment structures is considered as a research field of interest in remote sensing. In satellite observations of the earth's surface, continuous imaging in terms of time and space has caused the remote sensing technique to be proposed as a useful and efficient tool for the analysis of urban areas. Obtaining quantitative spatial information from the urban environment in fields such as determining the height of buildings plays an essential role in urban planning, monitoring damage to buildings, establishing communication bases and digital cities. During the last two decades, the use of Tomosar approach in order to reconstruct the structures of...
Joint Optimization of Computation Offloading and Resource Allocation in Mobile Edge Computing Networks
, M.Sc. Thesis Sharif University of Technology ; Pakravan, Mohammad Reza (Supervisor) ; Hadi, Mohammad (Co-Supervisor)
Abstract
Mobile edge computing (MEC) is a promising technology that aims to resolve cloud computing’s issues by deploying computation resources at the edge of mobile network and in the proximity of users. The advantages of MEC include reduced latency, energy consumption, and load on access and mobile core networks, to name but a few. Despite all the aforementioned advantages, the mobility of mobile network users causes the traditional MEC architecture to suffer from several issues, such as decreased efficiency and frequent service interruption. One of the methods to manage users’ mobility is virtual machine (VM) migration, where the VM containing the user’s task is migrated to somewhere closer to...
Estimating Price Elasticity of Natural Gas Demand in Iran's Residential Sector: A Regression Discontinuity Approach
, M.Sc. Thesis Sharif University of Technology ; Rahmati, Mohammad Hossein (Supervisor) ; Vesal, Mohammad (Supervisor)
Abstract
Estimating the price elasticity of gas demand involves complexities depending on the gas market structure and pricing mechanisms in different countries. Distinguishing between supply and demand shocks and block pricing are among the main challenges that can cause endogeneity in elasticity estimates. Iran's domestic gas network, one of the largest and most extensive household gas markets, is divided into five climatic zones based on weather conditions. The pricing steps for these five climates during the five cold months are such that a customer in a warmer climate pays higher prices. Conversely, the pricing steps for the seven warm months are the same for all climates. This policy creates a...
Estimate the Effect of Religiosity on Voter Turnout
, M.Sc. Thesis Sharif University of Technology ; Rahmati, Mohammad Hossein (Supervisor) ; Vesal, Mohammad (Supervisor)
Abstract
The correlation between religious adherence and voter turnout is widely studied. However, whether the relation is causal is an open question. We use Household Expenditures and Income Survey (HEIS) data in Iran, which encompasses nine distinct religious expenditures. These expenditures have low correlation with each other and represent different aspects of religious adherence. We use Imamzadeh (some historical holy shrines) as Instruments to estimate the causal effect of religious expenditures on voter turnout. The results reveal that religious expenditures influence both presidential and parliamentary voter turnout, with a notably stronger impact on presidential elections
Simulation and Control of an Aromatic Extractive Distillation Column
,
M.Sc. Thesis
Sharif University of Technology
;
Shahrokhi, Mohammad
(Supervisor)
Abstract
In this study steady state and dynamic simulation of an NFM extractive distillation unit for seperation of aromatics and non-aromatic components has been carried out. Column output composition obtained with experimental binary coefficients is compared with those obtainded by UNIFAC equation. The results indicate that using UNIFAC for all binrary coefficients results in an unacceptable error in concentration of benzene. If the experimental binary coefficents of benzene with NFM are used and the rest are calculated by UNIFAC equation, the simulation results will be very close to those obtained via experimental binary coefficients. Also it is shown that considering a constant efficiency for all...
Investigation of Transport Phenomena in Clarification of Beer by Membrane Using CFD Method
, M.Sc. Thesis Sharif University of Technology ; Soltanieh, Mohammad (Supervisor)
Abstract
During the brewing process, beer alternately goes through different chemical and biochemical reactions and solid–liquid separation stages. The clarification at the final step of brewing is a highly critical stage when it comes to producing a clear and bright beer. Recently, membrane technology has been successfully used in beer clarification, wherein Kieselguhr (diatomaceous earth) filtration is replaced by cross-flow microfiltration. The most important disadvantages of using microfiltration in clarification of beer is the fouling and flux decline during the process. The phenomenology of fouling mechanisms is still undefined and selection of an appropriate technique for flux enhancement in...