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rahimzadeh-rufuie--mehrdad
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Designing a MIPS Processor Using Transactional Level Modeling Tools
, M.Sc. Thesis Sharif University of Technology ; Vosoughi Vahdat, Bijan (Supervisor) ; Mortazavi, Mohammad (Supervisor)
Abstract
Processor cores in embedded applications is one the of important part of System-on-Chip designs. Among the most successful (Reduced Instruction Set Computer) RISC cores are the (Million Instruction Per Second) MIPS processors used in applications such as DVD, automotive, broadband access, networking, etc. In this work we have designed and verified Transaction Level Modeling (TLM) architecture of the MIPS in SystemC TLM2.0. The TLM in SystemC is adopted so that abstract data types can be used for higher (abstract) level modeling and faster simulation design. We implemented the processor such that the instruction and data caches contain all the necessary instructions and data to eliminate...
Flight envelope expansion in landing phase using classic, intelligent and adaptive controllers [electronic resource]
, Article Journal of aircraft ; 2006, Vol. 43, No. 1 ; Izadi, Hojjat Allah ; Pakme, Mehrdad
Abstract
An expanding flight envelope in the landing phase of a typical jet transport aircraft in presence of strong wind shears using a learning capable control system (LCCS) is investigated. The idea stems fromhuman beings functional architecture that gives them the ability to do more as they age and gain more experience. With the knowledge that classical controllers lack sufficient generality to cope with nonlinear as well as uncertain phenomenon such as turbulent air, the focuse is on different types of intelligent controllers due to their learning and nonlinear generalization capabilities as candidates for the landing flight phase. It is shown that the latter class of controllers could be used...
Analytical evaluation of saturation throughput of a cognitive wlan overlaid on a time-scheduled ofdma network
, Article IEEE Transactions on Mobile Computing ; Volume 16, Issue 3 , 2017 , Pages 634-647 ; 15361233 (ISSN) ; Ashtiani, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2017
Abstract
In this paper, we analyze the saturation throughput of a cognitive WLAN overlaid on a primary OFDMA TDD network (e.g., LTE or WiMAX). In this scenario, after the contention among the secondary nodes, the winner node transmits its data packet in the empty resource blocks (RBs) of downlink and uplink subframes of the primary network. Regarding the OFDMA structure as well as time-scheduled resources in the primary network, the time duration of opportunities for the secondary network does not follow simple exponential on-off pattern. To model the dynamic behavior of opportunities for secondary nodes as well as contentions to exploit the opportunities, we propose an analytical model comprised of...
A modified deep convolutional neural network for detecting COVID-19 and pneumonia from chest X-ray images based on the concatenation of Xception and ResNet50V2
, Article Informatics in Medicine Unlocked ; Volume 19 , 2020 ; Attar, A ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
In this paper, we have trained several deep convolutional networks with introduced training techniques for classifying X-ray images into three classes: normal, pneumonia, and COVID-19, based on two open-source datasets. Our data contains 180 X-ray images that belong to persons infected with COVID-19, and we attempted to apply methods to achieve the best possible results. In this research, we introduce some training techniques that help the network learn better when we have an unbalanced dataset (fewer cases of COVID-19 along with more cases from other classes). We also propose a neural network that is a concatenation of the Xception and ResNet50V2 networks. This network achieved the best...
An efficient graphyne membrane for water desalination
, Article Polymer ; Volume 175 , 2019 , Pages 310-319 ; 00323861 (ISSN) ; Moosavi, A ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Desalination of sea saline water seems a successful solution to supply clean water. For desalination, novel nanoporous membranes have been proposed as a substitute for the classic reverse osmosis (RO) membranes. The one-atom-thick graphyne membrane has shown great potential in water desalination. By applying functional groups (FGs) into the pores of the monolayer graphyne membranes, the water permeability and the ion rejection were passively increased. The effects of applying various FGs such as Hydrogen, Fluorine, Carboxyl and Amine, effect of the salt concentration, the applied pressure, and the effective diameter of the graphyne pores were determined by molecular dynamics (MD)...
Optimal Design of the Heliostat Field in the Solar Central Receiver Systems
, M.Sc. Thesis Sharif University of Technology ; Boroushaki, Mehrdad (Supervisor)
Abstract
In a solar central system plant about 40% of energy losses occurs in the heliostat field. Furtheremore, half of the investment costs for construction of the plant is related to the heliostat field. Therefore, an optimal design of the heliostat field is necessary for reduction of levelized cost of energy in solar tower power plants. In this study, in order to optimally design the heliostat field, first energy performance of the helistat field in one year is simulated. Solar power and sun’s position at each moment of the day is determined by mathematical relations. Then, loss factors in the field are modelled and heliostat field layout is designed by an algorithm. Finally, by using PSO...
Simulation and Multi-Objective Optimization of a Solar Micro CCHP Using Intelligent Techniques
, M.Sc. Thesis Sharif University of Technology ; Boroushaki, Mehrdad (Supervisor)
Abstract
Today, due to the scarcity of fossil energy resources, security of energy supply, and increasing environmental concerns, we need to develop new technologies to promote energy-saving and reduce greenhouse gas emissions. One of the suitable options for this purpose is to use the simultaneous production of electric power, cooling, and heating. Meanwhile, trigeneration systems that provide part of their energy needs from the sun, due to the free solar energy source and low environmental impact, can be an ideal technology for clean and safe scattered production. The present study has suggested a trigeneration system of cooling, heating, and power generation based on the organic Rankin cycle and...
Optimal Design of Induction MHD Generator for Electrical Power Generation from Exhaust of the Gas Turbine Power Plants
, M.Sc. Thesis Sharif University of Technology ; Boroushaki, Mehrdad (Supervisor)
Abstract
Today, due to increasing electricity consumption and demand, the use of conventional systems such as thermal, hydro and nuclear power plants is not enough to convert energy. Over the past century, scientists have sought to discover new technologies for exploiting different forms of energy and converting them into high-efficiency electrical energy. One of these ways is to use the phenomenon of magnetohydrodynamics (magnetic fluid dynamics) to convert thermal energy directly into electrical energy. Magnetohydrodynamics is a theoretical field that studies the dynamics of fluids with electrical conductivity. Induction magneto-hydrodynamic generators use ionized hot plasma (a quasi-neutral gas of...
Modeling and Optimal Design of a Solar Chimney Power Plant
, M.Sc. Thesis Sharif University of Technology ; Boroushaki, Mehrdad (Supervisor)
Abstract
The power generation system of this type of power plants operates on the air flowing through the power plant’s chimney and colliding with the turbine blades within the chimney. When the solar collector warms the nearby air and thus expands the air by absorbing the sunlight, a difference is created in the density. Then, this difference in the density creates the phenomenon of buoyancy, making the air pass to the top of the chimney through the collector.This study simulated and optimized a solar chimney power plant. The simulation and optimization were performed based on the information of Manzanares Solar Chimney Power Plant in Spain (located in 150 km from the south of Madrid). It was...
Intelligent Control of Hybrid Vehicles based on the Simultaneous Optimization of Fuel Consumption and Pollution Emission
, M.Sc. Thesis Sharif University of Technology ; Boroushaki, Mehrdad (Supervisor)
Abstract
The issue under discussion in this paper is to optimize the fuel consumption of the Toyota Prius hybrid car. In order to solve this problem, the ADVISOR design model used by NREL in the Matlab / Simulink environment has been used. Various parts of this model are described. The optimization performed on this issue is based on the emotional controller. This controller works by simulating learning in animals based on encouraging and punishing them. With the introduction of the controller, the model and its inclusion in the fuel consumption control and its implementation have achieved good results. In the initial state and the controller in the model, the fuel consumption was 4.9 liters per 100...
Active Control of Drag Force in Automobile in Order to Reduce Fuel Consumption
, M.Sc. Thesis Sharif University of Technology ; Boroushaki, Mehrdad (Supervisor)
Abstract
In this thesis, an attempt has been made to provide a smart and innovative system to optimize fuel consumption in cars by using the combination of engineering sciences, aerospace, and machine learning. Considering the current challenges of societies, the economic importance of saving fuel, as well as recent developments in the fields of machine learning and reinforcement learning, this research tries to improve the performance of cars in order to minimize the air resistance force of car bodies. In this regard, deep neural networks have been used to learn the dynamics of aerodynamic forces and reinforcement learning algorithms, especially DDPG (Deep Deterministic Policy Gradient), have been...
Traffic Prediction using Graph Neural Network
, M.Sc. Thesis Sharif University of Technology ; Boroushaki, Mehrdad (Supervisor)
Abstract
چکیده (انگلیسی) Prediction of traffic parameters is one of the most important needs in the field of intelligent transportation. Traffic forecasting allows people to choose the best times and routes to travel using various data such as date and time, events and weather conditions. Traffic forecasting helps reduce traffic in cities and save energy. This information is important for urban management; Because it provides the possibility of improving public transportation systems and traffic measures, and in this way, it is possible to propose the best solutions for managing traffic and increasing the quality of life of citizens. Although various parameters such as traffic speed, traffic...
چکیده (انگلیسی) Prediction of traffic parameters is one of the most important needs in the field of intelligent transportation. Traffic forecasting allows people to choose the best times and routes to travel using various data such as date and time, events and weather conditions. Traffic forecasting helps reduce traffic in cities and save energy. This information is important for urban management; Because it provides the possibility of improving public transportation systems and traffic measures, and in this way, it is possible to propose the best solutions for managing traffic and increasing the quality of life of citizens. Although various parameters such as traffic speed, traffic...
Improving the seismic torsional behavior of plan-asymmetric, single-storey, concrete moment resisting buildings with fluid viscous dampers
, Article Earthquake Engineering and Engineering Vibration ; Volume 15, Issue 1 , 2016 , Pages 61-78 ; 16713664 (ISSN) ; Mohammadzadeh, S ; Sharif University of Technology
Institute of Engineering Mechanics (IEM)
2016
Abstract
The optimal distribution of fluid viscous dampers (FVD) in controlling the seismic response of eccentric, single-storey, moment resisting concrete structures is investigated using the previously defined center of damping constant (CDC). For this purpose, a number of structural models with different one-way stiffness and strength eccentricities are considered. Extensive nonlinear time history analyses are carried out for various arrangements of FVDs. It is shown that the arrangement of FVDs for controlling the torsional behavior due to asymmetry in the concrete structures is very dependent on the intensity of the peak ground acceleration (PGA) and the extent of the structural stiffness and...
Application of active piezoelectric patches in controlling the dynamic response of a thin rectangular plate under a moving mass
, Article International Journal of Solids and Structures ; Volume 46, Issue 11-12 , 2009 , Pages 2429-2443 ; 00207683 (ISSN) ; Nikkhoo, A ; Sharif University of Technology
2009
Abstract
The governing differential equation of motion for an undamped thin rectangular plate with a number of bonded piezoelectric patches on its surface and arbitrary boundary conditions is derived using Hamilton's principle. A moving mass traveling on an arbitrary trajectory acts as an external excitation for the system. The effect of the moving mass inertia is considered using all the out-of-plane translational acceleration components. The method of eigenfunction expansion is used to transform the equation of motion into a number of coupled ordinary differential equations. A classical closed-loop optimal control algorithm is employed to suppress the dynamic response of the system, determining the...
Saturation Throughput Analysis of a Cognitive WLAN Overlaid on a Primary Network with Time-Scheduled Users
, M.Sc. Thesis Sharif University of Technology ; Ashtiani, Farid (Supervisor)
Abstract
The activity status of primary users in a cognitive network scenario is a key parameter in saturation throughput of the secondary users. In this respect, usually a simple on-off traffic model with exponentially distributed intervals is exploited. For time-scheduled users in modern common standards like WiMAX or LTE this traffic model is not valid anymore. In this thesis, we focus on the saturation throughput analysis of a cognitive network scenario, comprised of a WLAN overlaid on a network with time-scheduled primary users like WiMAX. In this scenario, the cognitive nodes (CNs) hear downlink map (DL-MAP) and thus, know the frequency and time locations of all allocated slots at each downlink...
The Impact of Human Capital on Labour Productivity in Manufacturing Sectors of Iran
,
M.Sc. Thesis
Sharif University of Technology
;
Sepahvand, Mehrdad
(Supervisor)
Abstract
This research has been surveyed the impact of intermediate skilled and high skilled human labor force on the productivity of manufacturing sectors by the Nelson & Phelps and also Lucas approaches. first model is related to the level of productivity and the second model is related to the growth of it. We has been prepared the needed statistics from the raw figures of iran statistics center. regression analysis has been done on the basis of panel data model by the use of stata software. the results show that not good efficiency to optimize technology factor of Cobb-Douglas model although it shows higher marginal labor productivity of high skilled human labor force. we has proposed some...
Design of a Wide Band Power Amplifier for Power DAC
, M.Sc. Thesis Sharif University of Technology ; Sharifbakhtiar, Mehrdad (Supervisor)
Abstract
Today’s radio transmitters must be able to send information in several standards. One problem involved in these wide band electronic systems lies in its end part, ie power amplifier. To have a broad band width either switching must be made among several power amplifiers with narrow band width (tuned) or the transistor part of power amplifier must be the same and single and selection be made only among matching networks. In this thesis, a power amplifier with broad band width without requiring a matching network has been designed and laid out. Also considering the low breakdown voltage of the gate oxide of the today’s standard CMOS transistors, it is very difficult to get a high output power...
Design of a HEV’s Controller Using Learning-based Methods
, M.Sc. Thesis Sharif University of Technology ; Boroushaki, Mehrdad (Supervisor)
Abstract
Hybrid electric vehicles (HEV) are proving to be one of the most promising innovations in advanced transportation systems to reduce air pollution and fossil fuel consumption. EMS is one of the most vital aspects of the HEV powertrain system. This research aims to design an optimal EMS under the condition of meeting the goals of drivability control, fuel consumption reduction, and battery charge stability. The current EMS is based on the classical rule-based method derived from fuzzy logic, which guides to the suboptimal solution in episodic driving cycles. Previous experiences in implementing Reinforcement Learning (RL) suffer from late convergence, instability in tracking the driving...
Optimal Design of Permanent Magnet Vernier Generator for Wind Power Plants Application
, M.Sc. Thesis Sharif University of Technology ; Boroushaki, Mehrdad (Supervisor)
Abstract
In recent decades, renewable energy resources (especially wind power as the fastest-growing energy source) have increasingly been employed for providing electrical energy all over the world given to the rising energy demands, reduction in non-renewable fossil fuels as well as severe restrictions applied to the utilization of these fuels because of their contribution in environmental pollution, generating greenhouse gas emissions, and consequently earth warming. The main factors in the development of wind energy systems to date are the easy access to this energy source in all seasons and its cost-effectiveness compared to other counterparts. One of the key components utilized for converting...
Design and Implementation of a Linear, 1 Watt, High Efficiency Power Amplifier with Controllable Output Power for UHF-RFID Application
, M.Sc. Thesis Sharif University of Technology ; Sharifbakhtiar, Mehrdad (Supervisor)
Abstract
Design and implementation of an efficient, 1 Watt, linear power amplifier (PA) with CMOS technology for UHF-RFID applications is presented in this thesis. Poor quality factor of inductors, high substrate noise and low breakdown voltage of CMOS, makes the implementation of Watt-level PAs challenging on this technology. Also the trade-off between linearity and efficiency, further hardens achieving an efficient high power linear PA. So the literature was reviewed first to come up with the appropriate structure of a linearized efficient PA. Afterwards, the structure was reformed and optimized for the application mentioned above with reasonable stability margins. Baseband relevant blocks were...