Loading...
Search for:
abdollahi--rahim
0.11 seconds
Total 182 records
Modeling and evaluation of software systems with object stochastic activity networks
, Article 2006 International Conference on Software Engineering Advances, ICSEA'06, Tahiti, 29 October 2006 through 3 November 2006 ; 2006 , Pages 58-63 ; 0769527035 (ISBN); 9780769527031 (ISBN) ; Movaghar, A ; Sharif University of Technology
IEEE Computer Society
2006
Abstract
Stochastic activity networks (SANs) are a stochastic generalization of Petri nets. SAN models have been used to evaluate a wide range of systems and are supported by several modeling tools. We have introduced object stochastic activity networks (OSANs) to overcome some restrictions of these models. OSANs integrate the concepts of object-orientation into SAN models. Elements of OSANs and their submodels are defined as classes. OSANs are more appropriate that most other objectoriented or high-level extensions of Petri nets for application on software systems. In this paper, we will present the definitions, behavior and an example of OSAN models. The objectorientation of OSANs and the...
A modeling tool for a new definition of stochastic activity networks
, Article Iranian Journal of Science and Technology, Transaction B: Engineering ; Volume 29, Issue 1 B , 2005 , Pages 79-92 ; 03601307 (ISSN) ; Movaghar, A ; Sharif University of Technology
2005
Abstract
Stochastic activity networks (SANs) are a powerful and flexible extension of Petri nets. Modeling and analysis with Petri nets and their extensions need a software tool to help to construct and analyze the models. The original definition of SANs has been used as a modeling formalism in several tools. In this paper, we introduce a modeling tool called SharifSAN, which is based on a new definition of SANs. This modeling tool is useful for both the verification and performance evaluation of systems. The functional aspects of a system are verified by model checking branching temporal logic formulas, whereas its performance aspects are evaluated using some analytic and simulative methods. The...
Modeling and evaluation with object stochastic activity networks
, Article Proceedings - First International Conference on the Quantitave Evaluation of Systems, QEST 2004, Enschede, 27 September 2004 through 30 September 2004 ; 2004 , Pages 326-327 ; 0769521851 (ISBN) ; Movaghar, A ; Sharif University of Technology
2004
Abstract
Stochastic activity networks (SANs) are a stochastic generalization of Petri nets. SAN models have been used for performance, dependability and performability evaluation and are supported by several powerful modeling tools. We have recently introduced object stochastic activity networks (OSANs) to overcome some restrictions of these models. OSANs integrate the concepts of object-orientation into SAN models. Elements of OSANs and their submodels are defined as classes. In this paper, we briefly introduce OSANs and SANBuilder tool for modeling and evaluation with these models. © 2004 IEEE
Stabilizing periodic orbits of fractional order chaotic systems via linear feedback theory
, Article Applied Mathematical Modelling ; Vol. 36, Issue 3 , 2012 , pp. 863-877 ; ISSN: 0307904X ; Salarieh, H ; Alasty, A ; Sharif University of Technology
2012
Abstract
In this paper stabilizing unstable periodic orbits (UPO) in a chaotic fractional order system is studied. Firstly, a technique for finding unstable periodic orbits in chaotic fractional order systems is stated. Then by applying this technique to the fractional van der Pol and fractional Duffing systems as two demonstrative examples, their unstable periodic orbits are found. After that, a method is presented for stabilization of the discovered UPOs based on the theories of stability of linear integer order and fractional order systems. Finally, based on the proposed idea a linear feedback controller is applied to the systems and simulations are done for demonstration of controller performance...
Investigating the Seismic Behavior of Steel Moment Resisting Structures using SMA Equipped Connections
, M.Sc. Thesis Sharif University of Technology ; Rahim Zadeh Rofooei, Fayyaz (Supervisor)
Abstract
Shape memory alloys (SMAs) are nowadays promising candidates for seismic engineering appli-cations due to their ability to undergo reversible deformations and to dissipate energy when subjected to cyclic loading. This thesis presents a numerical study of the torsional performance of structures equipped with end-plates connections using SMA as well as high strength steel bolts and identifies the required locations of SMA connections in a number of typical steel mo-ment resisting frames to improve their seismic torsional performance in terms of maximum inter-story drift and residual deformations. In this regard, 6 and 9-story steel structures were considered with eccentricity ratios of 0%,...
Design and Simulation of Spin Transport in Graphene Based Nanostructures
, Ph.D. Dissertation Sharif University of Technology ; Faez, Rahim (Supervisor) ; Pourfath, Mahdi (Co-Advisor)
Abstract
Graphene -a two-dimensional monolayer of graphite- was realized for the first time in 2004.Owing to its physical extra ordinary properties, graphene has attracted growing interest in research from fundamental physics to electronics, spintronics, and thermoelectrics. Importantly, it is an attractive material for electronics and spintronics due to its specific physical properties such as high electron mobility and gate tunable carrier concentration. Furthermore,achievement of room-temperature spin transport with relatively long spin relaxation time makes graphene nanoribbons the best candidate for spintronics. Based on the theoretical predictions, the weak spin-orbit interaction in graphene...
Design of 8 kV ESD Protection Circuit Compatibe with HBM in BCD Technology
, M.Sc. Thesis Sharif University of Technology ; Faez, Rahim (Supervisor) ; Medi, Ali (Supervisor)
Abstract
Electro Static discharge (ESD) in ICs can damage them. To prevent ICs from being damaged by ESD, protection circuits must be used. These protection circuits can be either designed on chip or on PCBs, to be more protective, both can be used. In this thesis, 8 kV ESD protection circuits according to human body model (HBM) in high voltage 0.18 um CMOS technology has been designed. In this thesis, in addition to study of electro static discharge phenomenon and its protection circuits, we have designed high voltage pads which are protected against 8 kV electro static discharge according to human body model. Finally these pads have been used in automotive ICs. In this thesis, firs we have...
Hardware Design for Cold Plasma Characterization Chamber
, M.Sc. Thesis Sharif University of Technology ; Rashidian, Bijan (Supervisor) ; Faez, Rahim (Supervisor)
Abstract
Cold plasma due to its special properties has many applications in the microelectronics industry. At the beginning of this study, a few examples of widely used plasmas and the requirements for driving their power sources have been investigated. To generate and characterize plasma, various topologies of DC power supply construction, including high-voltage low-current power supplies called multipliers and low-voltage high-voltage power supplies called converters, have been reviewed and compared.Circuit for pulse generating for plasma application has also been proposed and investigated. In the simulation section, after introducing, reviewing, and compareing the common types of simulators, the...
Modeling of Vertical Tunneling Transistor based on Gr-hBN-MoSe2 Heterostructure
, M.Sc. Thesis Sharif University of Technology ; Faez, Rahim (Supervisor)
Abstract
In this thesis, the transmission characteristics of a vertical tunneling transistors based on graphene-hBN-MoSe2 heterostructure is studied. We first obtain the tight-binding parameters required for Hamiltonian matrix and bandstructure calculations using density functional theory results. Once we have the tight-binding parameters, Hamiltonian and coupling matrices are calculated both of size 326×326. We then proceed to calulate the density of stated for source and drain contacts using the aforementioned matrices and nonequilibrium Green’s function(NEGF) formalism. We can then calculate the quantum capacitances of source and drain and acquire source/drain potentials using a capacitive circuit...
Investigating Excitation and Geometrical Effects on the Behavior of Cold Plasma
, M.Sc. Thesis Sharif University of Technology ; Rashidian, Bijan (Supervisor) ; Faez, Rahim (Supervisor)
Abstract
Cold plasma has many applications in micro electronics industry. In this study, several examples of widely used plasmas systems have been investigated. First, the theory and physics of each type of plasma has been studied. Then the applications of each type have been discussed. Finally, the accuracy of the statements has been investigated using COMSOL multi physics software. In 1&2 D simulations the effects of all macroscopic parameters on plasma properties and its behavior have been investigated. In the design of plasma excitation source, plasma impedance is a very important parameter for maximum power transfer. Plasma impedance has been calculated with COMSOL software. Different modes of...
Unstaedy Boundary Layer Measurement over an Airfoil in Plunging Motion
, M.Sc. Thesis Sharif University of Technology ; Soltani, Mohammad Reza (Supervisor)
Abstract
An experimental investigation of unsteady boundary layer over a wind turbine blade conducted in a subsonic wind tunnel. The experiment performed at different positions along the airfoil chord. Model was oscillated with amplitude of ±5 cm. Reynolds number, based on airfoil chord, ranged 3˟105 upto 6.5˟105 and the reduced frequency ranged from 0.0055 to 0.0981. Velocity profile measured with a total pressure rake. The data were reduced via a low-pass filter. Increasing the reduced frequency, the velocity profile increases the level on turbulence fluctuation and becomes more attached to the surface.
Synthesis, characterization and comparison of PAM, cationic PDMC and P(AM-co-DMC) based on solution polymerization
, Article Journal of Industrial and Engineering Chemistry ; Volume 17, Issue 3 , 2011 , Pages 580-586 ; 1226086X (ISSN) ; Frounchi, M ; Dadbin, S ; Sharif University of Technology
2011
Abstract
High molecular weight homopolymers of acrylamide (PAM) and (2-methacryloyloxyethyl) trimethyl ammonium chloride (PDMC) and copolymer of DMC with acrylamide (P(AM-co-DMC)) were synthesized using solution polymerization technique. The synthesized polymers were characterized by Fourier transform infrared (FTIR), 1HNMR, 13CNMR spectroscopy and differential scanning calorimetry (DSC) and viscometery. 1HNMR and 13CNMR studies confirmed the structure of the synthesized polymers. The behavior of the synthesized polymers was investigated in water-acetone and water-methanol mixtures. The plot of intrinsic viscosity of either PAM or P(AM-co-DMC) with respect to acetone (methanol)/water ratio in...
Study of atmospheric muons using a cosmic ray telescope
, Article Journal of Physics G: Nuclear and Particle Physics ; Volume 40, Issue 2 , 2013 ; 09543899 (ISSN) ; Bahmanabadi, M ; Purmohammad, D ; Sharif University of Technology
2013
Abstract
The charge ratio of cosmic muons holds important information for both the atmospheric neutrino anomaly and hadronic interaction models. In this paper we measured the muon charge ratio () in the cosmic ray flux in the momenta range 0.76-1.60 GeV/c by using a cosmic ray telescope. The delayed coincidence method is used based on the reduced mean lifetime of negative muons due to nuclear capture in matter. The systematic time-dependent effects of the muon charge ratio are considered by grouping the decay data into different time intervals. We compared the experimental data with the predictions of CORSIKA simulations using a high energy interaction model (QGSJET-II) and two low energy interaction...
Design and Control of a Robotic Arm and Hand with Simulation on Performance
, M.Sc. Thesis Sharif University of Technology ; Zohour, Hassan (Supervisor)
Abstract
The set of human arm, forearm, and wrist has the ability of performing very miscellaneous movements which has led to human inspiration for designing sorts of robots for various tasks. The aim of the present study is the design and simulation of a robot, similar to the human hand and arm. In the beginning, a shape-adaptive 2 DOF under-actuated mechanism which is actuated by one motor, is selected as the second and third phalanges of the human finger. Also the first phalanx of the finger moves independently by another motor. By adding a ratchet to the second joint of the finger, with the help of only two actuators, the feasibility of exerting isotropic force to the object in three phalanges...
Fixed Order Controller Design Via Convex Optimization
, M.Sc. Thesis Sharif University of Technology ; Nobakhti, Amin (Supervisor)
Abstract
In this thesis we introduce a new methodology to solve the problem of multi-objective control design of linear output-feedback with a constraint on the order of controller. This problem can be formulated as a set of linear matrix inequalities and an additional rank constraint. This constraint is highly non-convex and makes this optimization problem NP-hard. The proposed methodology results in methods which are multi-step and in each step a convex optimization problem shall be solved. This methodology can consider any combination of different design objectives such as H2 performance, H1 performance, passivity and regional pole assignment. In the development of described methodology, a...
Design and Development of a 5DoF Table Top Platform for Aircraft Dynamic Identification
, M.Sc. Thesis Sharif University of Technology ; Pourtakdoust, Hossein (Supervisor)
Abstract
Experimental identification (EI) of aircraft static and dynamic characteristics is usually performed for design process verification, its compliance against the existing regulations as well as to extraction of its exact stability and performance characteristics. EI is mostly performed via flight and/or wind tunnel testing of a scaled model of the aircraft under scrutiny. In this regard, the purpose of this thesis is design and development of a 5DoF Table Top Platform (TTP) for Aircraft transfer function identifications as well as some of its key derivatives. The proposed TTP can also function as the motion part of a miniature simulator. The PPT is designed in two parts that is comprised of...
Effect of Pore Size Distribution on Relative Permeability using Unsteady State Method Due to CO2 Injection
, M.Sc. Thesis Sharif University of Technology ; Masihi, Mohsen (Supervisor)
Abstract
The structure of a Pore and how The Pore and grains are distributed in it have a significant impact on the amount of fluid recovery and its production. In this research, the effect of the structure of the porous medium on the relative permeability curve and the amount of fluid recovery has been investigated, and 3 realistic, simplified and homogeneous models have been selected for this work. The simulation is that carbon dioxide gas is injected into an environment completely saturated with water. This work has been done in a water-loving environment and by examining three wettability levels of 30, 60 and 75. Simulation of fluid flow has been done in COMSOL software at the Pore scale. The...
Design and Development of a Space Solar Panel Electronic Simulator
, M.Sc. Thesis Sharif University of Technology ; Faez, Rahim (Supervisor) ; Taher Bane, Mohsen (Co-Advisor)
Abstract
The main power source of many space systems, are solar panels which are mainly affected from irradiance, temperature and particles radiation and an electronic solar panel simulator is a power-supply system that simulates the output of the solar panel. This system by processing of input data such as environment conditions, panel specifications and etc, simulate panel behavior and it can set the IV curve of the panel in different conditions. In this thesis, after introducing electronic solar panel simulators (chapter one), photovoltaic cells (chapter two) and space environment and its effects on space systems (chapter three), modeling solar panel based on the equivalent circuit of a solar...
Evaluation of the Effect of Temperature Gradient on the Dynamic Behavior of Concrete Arch Dams
, M.Sc. Thesis Sharif University of Technology ; Rahim Zadeh Rofooei, Fayyaz (Supervisor)
Abstract
Concrete arch dams, because of their special shape as a 3-D huge shell which is fixed from three sides, are very sensitive to temperature and its variation. Therefore, it is required to include the temperature variations and their related thermal stresses and strains in the safety analysis of dams. In this research, the effect of applying the thermal gradients caused by the most critical thermal conditions, on dynamic behavior of concrete arch dams was studied. For this purpose, first a roughly exact 3-D finite element model of Karoon ІV arch dam was prepared by ANSYS program. Then, the temperature distribution through the dam thickness was determined by Stucky-Derron method and in a more...
Analysis of Single Electron Transistor with Metallic Island and its Application in Logic Circuits
, M.Sc. Thesis Sharif University of Technology ; Faez, Rahim (Supervisor) ; Bagheri Shouraki, Saeed (Supervisor)
Abstract
As the traditional MOSFET is reaching to its scaling limit, it is crucial to find an alternative. Single Electron Devices have shown promising features, such as nano-scale dimensions and extremely low power consumption that can lead to new generation of integrated circuits. In this thesis we have presented an analytical study of metallic single electron devices, particularly single electron transistors (SET). We have illustrated our study with some major logic applications of SET. The main goal of this thesis is to develop simulation software for single electron circuits, comparable with the well-known commercial software “SIMON”, which can provide steady-state and transient analysis of the...