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hosseini-najafabadi--sajad
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Fast Centralized Model Predictive Control of Signal Splitting in Large Scale Urban Road Networks
, M.Sc. Thesis Sharif University of Technology ; Haeri, Mohammad (Supervisor)
Abstract
With the rapid increase in the number of vehicles and the limitations on the extension of transportation network infrastructure, the need for utilizing proper methods to reduce traffic congestion has become increasingly important. One way to reduce traffic congestion is to control the signal splitting of traffic lights. Model predictive control (MPC) has been utilized so far by using different models of traffic flow dynamics in this field. Due to the high computational effort of MPC at each step time, the real-time implementation for large-scale networks has become a big challenge. Store-And-forward (SAF) is one of the traffic flow models that, due to its simplicity, makes it possible to...
Acoustic emission-based methodology to evaluate delamination crack growth under quasi-static and fatigue loading conditions
, Article Journal of Nondestructive Evaluation ; Volume 37, Issue 1 , March , 2018 ; 01959298 (ISSN) ; Ahmadi Najafabadi, M ; Mohammadi, K ; Fotouhi, M ; Hosseini Toudeshky, H ; Mohammadi, R ; Sharif University of Technology
Springer New York LLC
2018
Abstract
The aim of this study was to investigate the applicability of acoustic emission (AE) technique to evaluate delamination crack in glass/epoxy composite laminates under quasi-static and fatigue loading. To this aim, double cantilever beam specimens were subjected to mode I quasi-static and fatigue loading conditions and the generated AE signals were recorded during the tests. By analyzing the mechanical and AE results, an analytical correlation between the AE energy with the released strain energy and the crack growth was established. It was found that there is a 3rd degree polynomial correlation between the crack growth and the cumulative AE energy. Using this correlation the delamination...
Secondary particles spectra in the decay of a polarized top quark with anomalous tWb couplings
, Article Journal of Physics G: Nuclear and Particle Physics ; Volume 34, Issue 1 , 2007 ; 09543899 (ISSN) ; Sharif University of Technology
2007
Abstract
An analytic expression for energy and angular dependence of a secondary charged lepton in the decay of a polarized top quark with anomalous tWb couplings in the presence of all anomalous couplings are derived. The angular distribution of the b-quark is derived as well. It is presented that the charged lepton spin correlation coefficient is not very sensitive to the anomalous couplings. However, the b-quark spin correlation coefficient is sensitive to anomalous couplings and could be used as a powerful tool in the search for non-SM coupling. © 2007 IOP Publishing Ltd
Semileptonic decay of a polarized top quark in the noncommutative standard model
, Article Physical Review D - Particles, Fields, Gravitation and Cosmology ; Volume 74, Issue 2 , 2006 ; 15507998 (ISSN) ; Sharif University of Technology
2006
Abstract
In this paper we study the noncommutative effects to the lepton spectrum from the decay of a polarized top quark. It is shown that the lowest contribution comes from the quadratic terms of the noncommutative parameter. The deviations from the standard model are significant for small values of the noncommutative characteristic scale. However, the charged lepton spin correlation coefficient has a remarkable deviation from the standard model from very low values of the noncommutative characteristic scale to 1 TeV. © 2006 The American Physical Society
Adversarial Attack to Deep Learning Networks via Imperceptible Sparse Perturbation
, M.Sc. Thesis Sharif University of Technology ; Ghaemmaghami, Shahrokh (Supervisor) ; Marvasti, Farokh (Supervisor) ; Amini, Sajad (Co-Supervisor)
Abstract
Nowadays, methods based on deep learning networks are the most effective artificial in telligence methods. Although they have achieved success in various fields (such as machine vision and object recognition), practical and experimental cases show the fragility of deep learning networks against perturbations and unwanted changes of the input pattern. All these perturbations must be in a way that the main class of the perturbed input pattern can be rec ognized by human, but the network makes a mistake in recognizing its correct class. This thesis seeks a more accurate evaluation by designing adversarial attacks such that the main class of the adversarial pattern is detectable by human...
Model predictive control of blood sugar in patients with type-1 diabetes
, Article Optimal Control Applications and Methods ; Volume 37, Issue 4 , 2016 , Pages 559-573 ; 01432087 (ISSN) ; Shahrokhi, M ; Sharif University of Technology
John Wiley and Sons Ltd
2016
Abstract
In this article, two adaptive model predictive controllers (AMPC) are applied to regulate the blood glucose in type 1 diabetic patients. The first controller is constructed based on a linear model, while the second one is designed by using a nonlinear Hammerstein model. The adaptive version of these control schemes is considered to make them more robust against model mismatches and external disturbances. The least squares method with forgetting factor is used to update the model parameters. For simulation study, two well-known mathematical models namely, Puckett and Hovorka which describe the dynamical behavior of patient's body have been selected. The performances and robustness of the...
Anomalous single top quark production at the LHC
, Article Physica Scripta ; Volume 82, Issue 3 , 2010 ; 00318949 (ISSN) ; Pooya, G ; Sharif University of Technology
2010
Abstract
The anomalous top quark interactions with gluon (tug, tcg) allow the production of single top quarks at the Large Hadron Collider (LHC). Using the angular distribution of the charged lepton from the W boson in the top decay, we show that with the data of 10 fb-1 of integrated luminosity and in the collisions with the center of mass energy of 14TeV, the anomalous up and charm quarks coupling parameters κu,c/Λ can be measured down to 0.005 and 0.007 TeV-1, respectively
Experimental and analytical study of telescopic lead yielding damper
, Article Journal of Constructional Steel Research ; Volume 150 , 2018 , Pages 371-383 ; 0143974X (ISSN) ; Pournamazian Najafabadi, E ; Sharif University of Technology
2018
Abstract
In this study, a novel type of passive energy dissipation device called a Telescopic Lead Yielding Damper (TLYD) is proposed and analyzed. This device comprises co-axial steel cylinders and lead rings, such that these rings act as shear locks between the steel cylinders. TLYDs dissipate energy through the plastic shear deformation of lead metal. The telescopic mechanism used in TLYDs allows these small-sized dampers to tolerate large axial displacements with low fatigue. For each telescopic level, a yield plateau is added to the hysteresis behavior of TLYD devices. Each yield plateau resists a different performance level, namely design-based and maximum credible earthquakes. Seven...
Wireless electrochemical preparation of gradient nanoclusters consisting of copper(II), stearic acid and montmorillonite on a copper wire for headspace in-tube microextraction of chlorobenzenes
, Article Microchimica Acta ; Volume 185, Issue 1 , 2018 ; 00263672 (ISSN) ; Bagheri, H ; Sharif University of Technology
Springer-Verlag Wien
2018
Abstract
This work introduces a new gradient fiber coating for microextraction of chlorobenzenes. Nanoclusters of organoclay-Cu(II) on a copper wire were fabricated by wireless electrofunctionalization. The resultant gradient coatings are more robust, and thermally and mechanically stable. Wireless electrofunctionalization was carried out in a bipolar cell under a constant deposition potential and using an ethanolic electrolyte solution containing stearic acid and montmorillonite. Stearic acid acts as an inexpensive and green coating while montmorillonite acts as a modifier to impart thermal stability. The gradient morphology of the nanoclusters was investigated by scanning electron microscopy,...
Modeling of retention behaviors of most frequent components of essential oils in polar and non-polar stationary phases
, Article Journal of Separation Science ; Volume 34, Issue 13 , 2011 , Pages 1538-1546 ; 16159306 (ISSN) ; Ebrahimi Najafabadi, H ; Sharif University of Technology
2011
Abstract
The gas chromatography retention indices of 100 different components of essential oils, on three columns with stationary phases of different polarities, were used to develop robust quantitative structure-retention relationship (QSRR) models. Two linear models with only one variable, i.e. solvation entropy, were developed, which explain 95 and 94% of variances of the test set for dimethyl silicone and dimethyl silicone with 5% phenyl group columns, respectively. These models are extremely simple and easy to interpret, but they show higher errors compared with more robust models such as partial least square (PLS) and ridge regressions. For the third column (polyethylene glycol (PEG)), 24...
The use of ladder particle swarm optimisation for quantitative structure-activity relationship analysis of human immunodeficiency virus-1 integrase inhibitors
, Article Molecular Simulation ; Volume 37, Issue 15 , 2011 , Pages 1221-1233 ; 08927022 (ISSN) ; Ebrahimi-Najafabadi, H ; Sharif University of Technology
2011
Abstract
This contribution focuses on the use of ladder particle swarm optimisation (LPSO) on modelling of oxadiazole- and triazolesubstituted naphthyridines as human immunodeficiency virus-1 integrase inhibitors. Artificial neural network (ANN) and Monte Carlo cross-validation techniques were combined with LPSO to develop a quantitative structure-activity relationship model. The techniques of LPSO, ANN and sample set partitioning based on joint x-y distances were applied as feature selection, mapping and model evaluation, respectively. The variables selected by LPSO were used as inputs of Bayesian regularisation ANN. The statistical parameters of correlation of deterministic, R2, and...
Mathematical performance modelling of adaptive wormhole routing in optoelectronic hypercubes
, Article Journal of Parallel and Distributed Computing ; Volume 67, Issue 9 , Volume 67, Issue 9 , 2007 , Pages 967-980 ; 07437315 (ISSN) ; Sarbazi Azad, H ; Sharif University of Technology
2007
Abstract
In this paper, an analytical performance model for adaptive wormhole routing in the hypercube-based optical transpose interconnection system (OTIS-hypercube) is proposed and validated. Using this model, the performance merits of the OTIS-hypercube are discussed. We also compare the performance of the OTIS-hypercube with that of equivalent hypercube network under different implementation constraints. Compared to pure simulation results, the presented model can serve as a more appropriate and compact method to display the performance characteristics of OTIS-hypercube networks. © 2007 Elsevier Inc. All rights reserved
Multiclass Visual Object Recognition Based On Cluttered Images
, M.Sc. Thesis Sharif University of Technology ; Kasaei, Shohreh (Supervisor)
Abstract
With the advancement of Machine Vision and Image Processing systems, the need for conceptual interpretation is raising. For this interpretation, one should detect objects available in the image and then tries to find the relations between the objects. For a good interpretation of the image, the machine vision system should learn patterns available in the nature. Object recognition systems are also used in other vision tasks and they can be used for content-based image retrieval, control and surveillance, or human action and gesture recognition for a better and easier human-computer interface. In an object recognition system, first some features should be extracted from the input image and...
Multisymplectic Geometry, Covariant Hamiltonian and Water Waves
, M.Sc. Thesis Sharif University of Technology ; Bahraini, Alireza (Supervisor)
Blood Glucose Control in Human Body Using Model-Based Controllers
,
M.Sc. Thesis
Sharif University of Technology
;
Shahrokhi, Mohammad
(Supervisor)
Abstract
Continous blood glucose control has great importance for type 1 dyabetic patients. In this thesis, several types of controllers including: PI controller, model predictive controller base on state space model, linear model predictive controller base of linear input-output model and non-linear model predictive controller base of Hammerstein model have been used to regulate blood glucose of patients with type 1 diabetes. These models are identified using least squars method. Performance of these controllers is tested and the best one is introduced. For rejecting meal disturbances, a feedforward controller has been designed. Combination of feedback and feedforward controller would properly...
Estimation of biodiesel physical properties using local composition based models
, Article Industrial and Engineering Chemistry Research ; Volume 51, Issue 41 , September , 2012 , Pages 13518-13526 ; 08885885 (ISSN) ; Pazuki, G ; Vossoughi, M ; Sharif University of Technology
2012
Abstract
In this study, the local composition based models such as the Wilson, the nonrandom two-liquid (NRTL), and the Wilson-NRF have been applied in correlation and estimation of density, viscosity, and surface tension of biodiesels. The thermodynamic models have been used in correlating the thermophysical properties for 215 experimental data points. These models have the interaction energy between each pair that is considered as adjustable parameters. To decrease the number of these adjustable parameters, it is assumed that the biodiesels are composed of two hypothetical components. The average absolute deviation (AADs) of the correlated density of biodiesels for the Wilson, the NRTL, and the...
Performance analysis of contact baking of flat bread in an indirect-heating oven
, Article Drying Technology ; Volume 30, Issue 9 , May , 2012 , Pages 1014-1023 ; 07373937 (ISSN) ; Feilizadeh, M ; Najafabadi, A. T ; Sharif University of Technology
2012
Abstract
A significant portion of Iranian flat breads are produced in semi-industrial, indirect-heating ovens. Therefore, an efficient oven design and a proper selection of operating conditions are crucial to improve the product quality and reduce energy consumption. In the present study, a mathematical model is developed to simulate a semi-industrial, indirect-heating, continuous oven performance during contact baking of an Iranian flat bread, referred to as Taftoon. Individual modes of heat transfer are considered among various components of the baking system to estimate the system performance and the bread quality in terms of design and operating conditions. The predictions of this model are in...
Modeling and Optimization of Energy Harvesting System by Means of Magnetic Shape Memory Alloy
, M.Sc. Thesis Sharif University of Technology ; Sayyadi, Hassan (Supervisor)
Abstract
Among different mechanisems for ambient energy harvesters, energy harvesting systems by means of magnetic shape memory alloys are noted due to their long life time, large strain amplitudes and the ability to operate at low frequencies. Strain change in these systems, changes the MSMA magnetization resulting change in the magnetic flux leading to inducing voltage by means of pickup coil. in the commercial systems, magnetic flux path is created by inserting an MSMA specimen in the air gap of ferromagnetic core and generation of bias magnetic field by means of the permanent magnet or electromagnet. In this proposed research, a thermodynamic based constitutive model is selected for the mdeling...
An RT-Level Low Power Design Technique for Digital Circuits Implemented on FPGAs
, M.Sc. Thesis Sharif University of Technology ; Ejlali, Alireza (Supervisor)
Abstract
RT-level techniques are one of the most important categories of techniques employed for decreasing power consumption in digital systems. These techniques are usually applied in the HDL description of the system, however some of them are applicable automatically by the synthesis tools. Some of the most commonly used RT-level techniques include Operand isolation, Clock gating, Concurrency & Redundancy, Pre-computation and Pipeline for low power. However these techniques have been mostly employed in ASIC designs, and FPGAs have scarcely been addressed. Application of these techniques on FPGAs might need special considerations, since resources on FPGAs are inherently different than their ASIC...
Experimental and Numerical Modeling of Telescopic Damper
, M.Sc. Thesis Sharif University of Technology ; Eskandari, Morteza (Supervisor)
Abstract
This study proposes a new metallic yielding damper for seismic applications. First, considering the damper proposed by curadelli in 2009 a simple lead yielding damper was manufactured to determine its maximum allowable axial deformation showing that it cannot tolerate suitable axial deformations. To solve this problem a telescopic damper with curadelli damper’s descriptions was manufactured and tested which increased the last damper’s allowable deformation 100%. Although new damper’s allowable deformation is twofold the old one, it was not enough for seismic applications. In the next step 6 dampers called lead shear dampers (LSD) with modified lead section were tested. LSD deformation...