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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...
Mind-Body Problem from Wittgenstein’s Perspective
, M.Sc. Thesis Sharif University of Technology ; Hojjat, Mino (Supervisor)
Abstract
To provide a stable foundation for human knowledge Descartes presumed that human being is composed of two distinct substances, the mind and the body. But, the solution through which he wanted to explain the correlation between these substances, was not accepted by other philosophers, and thereafter this problem was known as mind-body problem. This problem arises some other philosophical problems including solipsism and the problem of other minds. In this thesis, considering the grammar of such words like memory, understanding, and thinking I will show that having an exact description of these concepts we would be able to escape from these inclination to seek something behind these words, and...
Designing a System for Pulse Pile-Up Processing in Gamma Ray Spectroscopy Based on Digital Method
, M.Sc. Thesis Sharif University of Technology ; Hosseini, Abolfazl (Supervisor)
Abstract
In Radiation Detection Systems applied in Spectroscopy and Imaging, if the rate of particle incidence with detector is high, the output pulses being stacked up on each other will be expected, which is known as “Pulse Pile-up”. Pulse pile-up might result in a serious disorder of energy and timing data expected from the pulses. In recent decades and after successful implementation of pile-up rejection methods on analog circuits, considering development and progression in the field of digital, different algorithms based on pileup correction methods have been developed to obtain all spectrum information, whether energy, rise time and recorded pulses. Such methods can be compared in different...
Modified WK-Recursive Topology for an Optical Network-on-Chip
, M.Sc. Thesis Sharif University of Technology ; Hesabi, Shahin (Supervisor)
Abstract
Nowadays, a large proportion of the power consumption in high-performance multi-processor architectures on chip belongs to connections. Reducing power consumption while maintaining high efficiency in these architectures is one of the main concerns. Networks on Chip (NoC) originally were introduced to improve efficiency, but now, given the importance of power, we must provide some solutions to reduce power consumption, and delay in NOCs. Connections in chip can be divided into three categories: global, intermediate and local, while the length of global connections is almost constant in different scales, local connections are scalable. As a result improving efficiency of a small number of...
A Survey on the Effect of Travel Mode Choice on Citizens’ Subjective Wellbeing
, M.Sc. Thesis Sharif University of Technology ; Kermanshah, Mohammad (Supervisor)
Abstract
Different definitions of the term ‘subjective well-being’ have been defined by different researchers. While there is no definite definition for this concept, it can be related to one's life evaluation. The issue of citizens’ subjective well-being has not usually been considered in transportation policies, such as reducing single occupancy vehicle. However, subjective well-being reflects the individuals’ quality of life and can be one of the main priorities of any society. This study tries to find the effect of using various modes of travel including passenger car, motorcycle, public transportation and walking on citizens' subjective well-being. Subjective well-being is measured by...
Synthesis and Comparative Study on Complex Formation of Azo-bearing Nitrogen-Donor Macrocyclic Ligands with Fullerene C60 and Cu(II) Cation
, Ph.D. Dissertation Sharif University of Technology ; Ghanbari, Bahram (Supervisor)
Abstract
In the present research, a series of bimacrocyclic tweezer anchored through azobenzene moiety were synthesized and characterized by applying IR spectroscopy, 1H and 13C{1H} NMR, fluorescence spectroscopy, UV-visible spectroscopy, mass spectrometry and elemental analysis and in some cases by X-ray crystallography. Firstly, UV-visible spectroscopy established that the irradiation of the tweezers with UV light promoted the trans to cis isomerization. On the other hand, thermal cis-trans isomerization behavior of the azobenzene moiety in tweezers was surveyed in which the cis isomers were formed of the heating at 50 oC for 5 minutes. Where the -OH group was replaced with 4-toluenesulfonyl...
Integrating module checking and deduction in a formal proof for the perlman Spanning Tree Protocol (STP)
, Article Journal of Universal Computer Science ; Volume 13, Issue 13 , 2007 , Pages 2076-2104 ; 0958695X (ISSN) ; Nakhost, H ; Sirjani, M ; Sharif University of Technology
2007
Abstract
In the IEEE 802.1D standard for the Media Access Control layer (MAC layer) bridges, there is an STP (Spanning Tree Protocol) definition, based on the algorithm that was proposed by Radia Perlman. In this paper, we give a formal proof for correctness of the STP algorithm by showing that finally a single node is selected as the root of the tree and the loops are eliminated correctly. We use formal inductive reasoning to establish these requirements. In order to ensure that the bridges behave correctly regardless of the topology of the surrounding bridges and LANs, the Rebeca, modular verification techniques are applied. These techniques are shown to be efficiently applicable in model checking...
Optimal active control of vehicle suspension system including time delay and preview for rough roads
, Article JVC/Journal of Vibration and Control ; Volume 8, Issue 7 , 2002 , Pages 967-991 ; 10775463 (ISSN) ; Ahmardi, G ; Hojjat, Y ; Zohoor, H ; Sharif University of Technology
SAGE Publications Inc
2002
Abstract
An optimal preview control of a vehicle suspension system traveling on a rough road is studied. A three-dimensional seven degree-of-freedom car-riding model and several descriptions of the road surface roughness heights, including haversine (hole/bump) and stochastic filtered white noise models, are used in the analysis. It is assumed that contact-less sensors affixed to the vehicle front bumper measure the road surface height at some distances in the front of the car. The suspension systems are optimized with respect to ride comfort and road holding preferences including accelerations of the sprung mass, tire deflection, suspension rattle space and control force. The performance and power...
Stochastic optimal preview control of a vehicle suspension
, Article Journal of Sound and Vibration ; Volume 275, Issue 3-5 , 2004 , Pages 973-990 ; 0022460X (ISSN) ; Ahmadi, G ; Zohoor, H ; Hojjat, Y ; Sharif University of Technology
Academic Press
2004
Abstract
Stochastic optimal control of a vehicle suspension on a random road is studied. The road roughness height is modelled as a filtered white noise stochastic process and a four-degree-of-freedom half-car model is used in the analysis. It is assumed that a sensor is mounted in the front bumper that measures the road irregularity at some distances in the front of the vehicle. Two other sensors also measure relative velocities of the vehicle body with respect to the unsprung masses in the vehicle suspension spaces. All measurements are assumed to be conducted in a noisy environment. The state variables of the vehicle system are estimated using a method similar to the Kalman filter. The suspension...
The effect of sol-gel surface modified silver nanoparticles on the protective properties of the epoxy coating
, Article RSC Advances ; Volume 6, Issue 23 , 2016 , Pages 18996-19006 ; 20462069 (ISSN) ; Haddadi, S. A ; Mahdavian, M ; Sharif University of Technology
Royal Society of Chemistry
2016
Abstract
In this study, the effect of surface modified silver nanoparticles on the corrosion protection of an epoxy coating on mild steel was studied. An organosilane (3-methoxy silyl propyl metacrylate) was used as a surface modifier to increase the dispersability of the inorganic nanoparticles in the organic epoxy coating matrix. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) were used to characterize the surface modified nanoparticles. Differential scanning colorimetry (DSC) was employed to study the effects of modified and unmodified nano-silver on the curing heat and glass transition temperature of the epoxy coatings. Salt spray and electrochemical impedance...
Smart antennas for OFDM-WLANs based on a spatial-temporal multi-scenario channel model
, Article Iranian Journal of Electrical and Computer Engineering ; Volume 7, Issue 2 , 2008 , Pages 107-114 ; 16820053 (ISSN) ; Dadashzadeh, G ; Shishegar, A. A ; Hojjat, N ; Sharif University of Technology
Jahad Daneshgahi
2008
Abstract
combination of smart antenna techniques and OFDM could be considered as a promising solution for improving the performance and enhancing the data rates of next generation wireless communication systems operating in frequency selective fading environments. There are different design parameters which could affect the application of adaptive arrays in OFDM-based systems. Various beam-forming methods in frequency or time domain, different array architectures and various number of array elements are important factors which are able to change the performance and complexity of the system. These parameters may show different effects in different channel conditions. In this paper we implemented a new...
Hybrid particle swarm-based-simulated annealing optimization techniques
, Article IECON 2006 - 32nd Annual Conference on IEEE Industrial Electronics, Paris, 6 November 2006 through 10 November 2006 ; 2006 , Pages 644-648 ; 1424401364 (ISBN); 9781424401369 (ISBN) ; Zamani, M ; Feyz Mahdavian, H. R ; Sharif University of Technology
2006
Abstract
Particle Swarm Optimization (PSO) algorithms recently invented as intelligent optimizers with several highly desirable attributes. In this paper, two new hybrid Particle Swam Optimization schemes are proposed. The proposed hybrid algorithms are based on using the Particle Swarm Optimization techniques in conjunction with the Simulated Annealing (SA) approach. By simulating three different test functions, it is shown how the proposed hybrid algorithms offer the capability of converging toward the global minimum or maximum points. More importantly, the simulation results indicate that the proposed hybrid particle swarm-based simulated annealing approaches have much superior convergence...
Partial order reduction for timed actors
, Article 13th International Conference on Verified Software: Theories, Tools, and Experiments, VSTTE 2021 and 14th International Workshop on Numerical Software Verification, NSV 2021, 18 October 2021 through 19 October 2021 ; Volume 13124 LNCS , 2022 , Pages 43-60 ; 03029743 (ISSN); 9783030955601 (ISBN) ; Sirjani, M ; Khamespanah, E ; Hojjat, H ; Movaghar, A ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
We propose a compositional approach for the Partial Order Reduction (POR) in the state space generation of asynchronous timed actors. We define the concept of independent actors as the actors that do not send messages to a common actor. The approach avoids exploring unnecessary interleaving of executions of independent actors. It performs on a component-based model where actors from different components, except for the actors on borders, are independent. To alleviate the effect of the cross-border messages, we enforce a delay condition, ensuring that an actor introduces a delay in its execution before sending a message across the border of its component. Within each time unit, our technique...
A Model for Logistics Management in Natural Disaster Relief
, M.Sc. Thesis Sharif University of Technology ; Eshghi, Kourosh (Supervisor) ; Najafi, Mehdi (Co-Advisor)
Abstract
Research and information available shows that the number of natural disasters are increasing dramatically; hence disaster management is being raised as one of the most important topics in this field. The relief logistics is the greater part of disaster management model.
In this study, in order to manage the logistics activities effectively in a response phase of an earthquake, a hybrid meta-heuristic algorithm is developed for a transportation network. Then, the proposed algorithm is tested on a small part of Tehran.
In this study, in order to manage the logistics activities effectively in a response phase of an earthquake, a hybrid meta-heuristic algorithm is developed for a transportation network. Then, the proposed algorithm is tested on a small part of Tehran.
Robust multiple model adaptive control using fuzzy fusion
, Article 2010 42nd Southeastern Symposium on System Theory, SSST 2010, Tyler, TX, 7 March 2010 through 9 March 2010 ; March , 2010 , Pages 19-24 ; 9781424456901 (ISBN) ; Dumont, G. A ; Feyz Mahdavian, H. R ; Sharif University of Technology
2010
Abstract
A robust multiple model adaptive control strategy using fuzzy fusion (RMMAC-FF) is presented in this paper. The main idea in multi-model controllers is to identify the best model of the system at any instant of time and apply the appropriate control input to it. RMMAC-FF, integrates a fuzzy robust controller, with the fuzzy multiple model adaptive estimation and a fuzzy switching to come up with a new strong methodology to control complex systems. Simulation results of the RMMAC-FF on a two-cart system, used as a benchmark problem, verify the theory and confirm the effectiveness of the proposed controller
Adsorption of eco-friendly carthamus tinctorius on steel surface in saline solution: a combination of electrochemical and theoretical studies
, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 601 , 20 September , 2020 ; Ramazani Saadat Abadi,A ; Mahdavian, M ; Bahlakeh, G ; Haddadi, S. A
Elsevier B.V
2020
Abstract
In this study, the different parts of carthamus tinctorius plant, including petal (SPE), leaf (SLE), and shoot (SSE), have been extracted. Adsorption of the extracts on mild steel in 3.5 wt. % NaCl solution was evaluated employing electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, and electrochemical noise measurements (EN). The field-emission scanning electron microscopy (FE-SEM) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) were employed to appraise the morphology of the samples surface subjected to the test solutions. According to the EIS results, the maximum adsorption efficiency belonged to the solution containing 1 g L−1 of...
Falcaria vulgaris leaves extract as an eco-friendly corrosion inhibitor for mild steel in hydrochloric acid media
, Article Scientific Reports ; Volume 13, Issue 1 , 2023 ; 20452322 (ISSN) ; Ghaderi, M ; Ramazani Saadatabadi, A ; Mahdavian, M ; Sharif University of Technology
Nature Research
2023
Abstract
Undoubtedly, metal corrosion is one of the most challenging problems faced by industries. Introducing corrosion inhibitors is a reasonable approach to protecting the metal surface. Due to environmental concerns and the toxicity of industrial organic corrosion inhibitors, researchers are continually exploring acceptable replacements. The current study focused on the application of Falcaria Vulgaris (FV) leaves extract to mitigate mild steel (MS) corrosion in a 1 M HCl environment. The polarization findings demonstrated that the corrosion current density decreased from 264.0 µA/cm2 (for the sample submerged in the blank solution) to 20.4 µA/cm2 when the optimal concentration of 800 ppm of FV...
Development of an active/barrier bi-functional anti-corrosion system based on the epoxy nanocomposite loaded with highly-coordinated functionalized zirconium-based nanoporous metal-organic framework (Zr-MOF)
, Article Chemical Engineering Journal ; 2020 ; Ramezanzadeh, B ; Bahlakeh, G ; Tati, A ; Mahdavian, M ; Sharif University of Technology
Elsevier B.V
2020
Abstract
For the first time, the UIO-66, NH2-UIO, and NH2-UIO particles covalently functionalized by Glycidyl Methacrylate (GMA@NH2-UIO), were utilized as the novel functional anti-corrosive fillers. The functionality, high surface area, phase composition, excellent thermal properties as well as chemical stability of the Zr-MOFs were proved by FT-IR, BET, XRD, TGA, and water stability tests, respectively. The smart pH-sensitive controlled-release activity of the corrosion inhibitors (i.e., Zr ions and organic compounds) from the prepared Zr-MOFs was proved by the water stability test of the Zr-MOFs particles in the acidic (pH = 2), neutral (pH = 7.5), and alkaline (pH = 12) solutions containing 3.5...
Epoxy nanocomposite coatings with enhanced dual active/barrier behavior containing graphene-based carbon hollow spheres as corrosion inhibitor nanoreservoirs
, Article Corrosion Science ; Volume 185 , 2021 ; 0010938X (ISSN) ; Ramazani Saadatabadi, A ; Mahdavian, M ; Arjmand, M ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Graphene-based carbon hollow spheres (CHSs) fabrication, doped with 2-mercaptobenzimidazole (MBI) was successfully done in previous work. The active/barrier corrosion protection performance (CPP) of epoxy coatings was evaluated using salt spray test, electrochemical impedance spectroscopy (EIS), and scanning vibrating electrode technique (SVET). Results proved the active/barrier CPP enhancement of epoxy coatings in the presence of 3 wt. % MBI@CHSs. While the presence of MBI and empty CHSs in epoxy coatings did not further improve the active performance. An improvement in the adhesion loss of the epoxy coating, ca. 58 %, was observed in the presence of 3 wt. % MBI@CHSs. © 2021
Development of an active/barrier bi-functional anti-corrosion system based on the epoxy nanocomposite loaded with highly-coordinated functionalized zirconium-based nanoporous metal-organic framework (Zr-MOF)
, Article Chemical Engineering Journal ; Volume 408 , 2021 ; 13858947 (ISSN) ; Ramezanzadeh, B ; Bahlakeh, G ; Tati, A ; Mahdavian, M ; Sharif University of Technology
Elsevier B.V
2021
Abstract
For the first time, the UIO-66, NH2-UIO, and NH2-UIO particles covalently functionalized by Glycidyl Methacrylate (GMA@NH2-UIO), were utilized as the novel functional anti-corrosive fillers. The functionality, high surface area, phase composition, excellent thermal properties as well as chemical stability of the Zr-MOFs were proved by FT-IR, BET, XRD, TGA, and water stability tests, respectively. The smart pH-sensitive controlled-release activity of the corrosion inhibitors (i.e., Zr ions and organic compounds) from the prepared Zr-MOFs was proved by the water stability test of the Zr-MOFs particles in the acidic (pH = 2), neutral (pH = 7.5), and alkaline (pH = 12) solutions containing 3.5...