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computational-methods
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, Ph.D. Dissertation Sharif University of Technology ; Matloubi Moghaddam, Firouz (Supervisor)
Abstract
We have reported a new and efficient synthesis of a broad spectrum of heterotetracyclic benzoxazocines via unique tandem 1,3-dinucleophilic addition of different bifunctional nucleophiles to quinolinium and isoquinolinium salts. The reaction generally involves the initial addition of nucleophiles to quinolinium salts to form enamine intermediate which can be trapped by intramolecular O/S-alkylation of nucleophiles. In the third part, as continues, we have reported another method which consists of Anthocyanidins and Thioindoles by using water and acetic acid as the solvent. This protocol is a very mild and simple method for construction of eight-membered ring in fused heterocycles in a...
Modeling of Visual Attention Mechanism by Brain Signals
,
M.Sc. Thesis
Sharif University of Technology
;
Beigy, Hamid
(Supervisor)
Abstract
Attention is a cognitive process in which the mind reacts to certain stimuli or stimuli of the environment while other environmental stimuli are ignored. Attention might be an overt or covert process. Overt attention is a process in which based on the purpose, we selectively choose an object or place among other objects and places to focus on and we are aware of it. However, the covert attention originates from hidden source, and we are not aware of it. In fact, the covert attention causes a clear and rapid movement of the eye toward the stimulus or space to be taken into consideration and the time when the movement of the eye it means overt attention has occurred. Visual attention is given...
Experimental Study on Extracting Clean Energy from Vortex Induced Vibration
, M.Sc. Thesis Sharif University of Technology ; Abbaspour, Majid (Supervisor)
Abstract
Two experimental models were designed and tested to extract energy from vortex induced vibrations of a elastically mounted one degree of freedom rigid cylinder in the Reynolds range of 120000 < Re <220000. In the first model the amplitude and frequency of the movement was measured then a second model was designed to be tested in the Emam Hossein marine laboratory. The model was designed in a way that many of its properties like mass ratio, spring constant and damping coefficient were able to be altered. In this study the vortex induced vibration of an elastically mounted cylinder was scrutinized in high Reynolds and very low mass ratios for the first time and an amplitude ratio of 2.49 were...
Protein Function Prediction Using Protein Structure and Computational Methods
, M.Sc. Thesis Sharif University of Technology ; Fatemizadeh, Emad (Supervisor) ; Arab, Shahriar ($item.subfieldsMap.e)
Abstract
Predicting the Amino Acids that have a catalytic effect in the enzymes, is a big step in appointing the activity of the enzymes and classifying them. This is a very challenging job, because an Amino Acid can appear in a variety of active sites.The biological activity of a protein usually depends on the existence of a small number of Amino Acids. Detecting these Amino Acids from the sequence of Amino Acids has many applications. Usually, the Amino Acids that are preserved are known as the Amino Acids that build up the active site, but the algorithms for finding the preserved Amino Acids are much more complex. There are a lot of algorithms for predicting the active sites of Amino Acids, but...
A Model for Analysis of Computational Learning
, M.Sc. Thesis Sharif University of Technology ; Daneshgar, Amir (Supervisor)
Abstract
The subject of this thesis is about a certain set of algorithms that try to indirectly solve problems. Instead of a programmer crafting an algorithm to solve a problem, these algorithms learn a solution themselves. These methods are usually studied in the Probably Accurately Correct (PAC) learning model. Although, PAC Learning is a generally accepted model, it falls short to describe certain aspects of learning algorithms. Many learning methods rely on convergence to minimize error, or maximize their fitness, yet the PAC model doesn’t explicitly provide any means to measure these behaviours. In this thesis, we first go through different models related to computational requirements of...
Investigation of Thermodynamic Relations in Microscopic Systems by Quantum Information Theory
, M.Sc. Thesis Sharif University of Technology ; Shafiee, Afshin (Supervisor) ; Shamkhali, Amir Naser (Supervisor)
Abstract
Entropy is one of the important quantities in thermodynamics. In this project has tried to make this quantity as a bridge between quantum and thermodynamics. Entropy has many definitions that the Shannon entropy is chosen in this work. By this definition of entropy, we are able to define the entropy for a electronic system in molecules. By this definition, we are seeking an answer for this question,”whether entropy has a similar application in quantum like thermodynamics or not?”. To elucidate this hypothesis, simple diatomic molecules are computed. In fact, displacement of the Shannon entropy has investigated in bond making process. The question is that whether we can use this quantity to...
Investigating the Effect of the Proposed CSF-1R Protein Inhibitor,with a Structure Containing Natural Biomolecules and based on the Approved Drug Vimseltinib
, M.Sc. Thesis Sharif University of Technology ; Fattahi, Alireza (Supervisor)
Abstract
Vimseltinib, a small molecule inhibitor, represents a promising avenue for combating cancers linked to macrophage-associated processes through its targeted action on the CSF1R tyrosine kinase receptor. CSF1R, a pivotal member of the tyrosine kinase receptor family, plays a crucial role in macrophage differentiation and function. This protein's significance is underscored in conditions such as tenosynovial giant cell tumors (TGCTs) and the presence of tumor-associated macrophages, wherein overproduction of CSF1 by neoplastic cells recruits CSF1R-dependent immune cells, fostering tumor expansion. The intricate interplay extends to tumor-associated macrophages, particularly the M2 subtype,...
Sensitivity analysis of the OWA operator
, Article IEEE Transactions on Systems, Man, and Cybernetics, Part B: Cybernetics ; Volume 38, Issue 2 , 2008 , Pages 547-552 ; 10834419 (ISSN) ; Szidarovszky, F ; Ardakanian, R ; Sharif University of Technology
2008
Abstract
The successful design and application of the ordered weighted averaging (OWA) method as a decision-making tool depend on the efficient computation of its order weights. The most popular methods for determining the order weights are the fuzzy linguistic quantifiers approach and the minimal variability method, which give different behavior patterns for the OWA. These two methods will be first analyzed in detail by using sensitivity analysis on the outputs of the OWA with respect to the optimism degree of the decision maker, and then the two methods will be compared. The fuzzy linguistic quantifiers approach gives more information about the behavior of the OWA outputs in comparison to the...
Analog computing by Brewster effect
, Article Optics Letters ; Volume 41, Issue 15 , 2016 , Pages 3467-3470 ; 01469592 (ISSN) ; Zangeneh Nejad, F ; Abdollahramezani, S ; Khavasi, A ; Sharif University of Technology
OSA - The Optical Society
Abstract
Optical computing has emerged as a promising candidate for real-time and parallel continuous data processing. Motivated by recent progresses in metamaterial-based analog computing [Science 343, 160 (2014)], we theoretically investigate the realization of two-dimensional complex mathematical operations using rotated configurations, recently reported in [Opt. Lett. 39, 1278 (2014)]. Breaking the reflection symmetry, such configurations could realize both even and odd Green's functions associated with spatial operators. Based on such an appealing theory and by using the Brewster effect, we demonstrate realization of a firstorder differentiator. Such an efficient wave-based computation method...
Time and space extended-particle in cell model for electromagnetic particle algorithms
, Article Physics of Plasmas ; Volume 19, Issue 3 , 2012 ; 1070664X (ISSN) ; Anvari, A ; Sharif University of Technology
Abstract
A general method for deriving electromagnetic particle in cell (EMPIC) algorithms has been given by Eastwood [Comput. Phys. Commun. 64, 252 (1991)]. This method devises variation of the action-integral to find discrete governing equations. The most important advantage of this method is automatic inclusion of the time coordinate via the action integral into the computational domain. This inclusion is inevitable because electromagnetic algorithms are based on time evolution of the system from its initial state. The drawback of this method is that it is rather abstract. This causes obscurity of particle-mesh interactions and makes it hard to analyze physical treatments of the computational...
Computing watermark capacity in images according to their quad tree
, Article 5th IEEE International Symposium on Signal Processing and Information Technology, Athens, 18 December 2005 through 21 December 2005 ; Volume 2005 , 2005 , Pages 823-826 ; Jamzad, M ; Sharif University of Technology
2005
Abstract
Determining the capacity of watermark for images is a complex task. This capacity may be influenced by many factors such as the content of image and also the strength of watermark. In some recent works the image content has been considered for calculation of watermark capacity. One such approach is to use the Noise Visibility Function (NVF) introduced in [3]. In this paper we introduced a new method for finding NVF according to the quad tree representation of image instead of using pixel neighborhood data. Our experimental results showed that the depth of a pixel in image quad tree represents much information about the pixel and its maximum allowable distortion compared to pixel neighborhood...
Nonlinear ultrasound propagation through layered liquid and tissue-equivalent media: Computational and experimental results at high frequency
, Article Physics in Medicine and Biology ; Volume 51, Issue 22 , 2006 , Pages 5809-5824 ; 00319155 (ISSN) ; Cherin, E ; Lam, T. Y. J ; Tavakkoli, J ; Zemp, R. J ; Foster, F. S ; Sharif University of Technology
2006
Abstract
Nonlinear propagation has been demonstrated to have a significant impact on ultrasound imaging. An efficient computational algorithm is presented to simulate nonlinear ultrasound propagation through layered liquid and tissue-equivalent media. Results are compared with hydrophone measurements. This study was undertaken to investigate the role of nonlinear propagation in high frequency ultrasound micro-imaging. The acoustic field of a focused transducer (20 MHz centre frequency, f-number 2.5) was simulated for layered media consisting of water and tissue-mimicking phantom, for several wide-bandwidth source pulses. The simulation model accounted for the effects of diffraction, attenuation and...
Phonon frequency calculations of GdBCO and PrBCO
, Article 4th International Conference on Magnetic and Superconducting Materials, MSM'05, Agadir, 5 September 2006 through 8 September 2006 ; Volume 3, Issue 9 , 2006 , Pages 3162-3165 ; 18626351 (ISSN) ; Khasroabadi, H ; Akhavan, M ; Sharif University of Technology
2006
Abstract
Ab initio frozen-phonon calculations have been performed for k = 0 A g Raman modes of superconducting GdBa2Cu3O 7 and insulating PrBa2Cu3O7. We have used the generalized gradient approximation full-potential linear augmented plane-wave method in our calculations by Wien2k code. Results have been compared with other computational and experimental data for similar systems. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA
A recursive approach for the analysis of snake robots using Kane's equations
, Article Robotica ; Volume 24, Issue 2 , 2006 , Pages 251-256 ; 02635747 (ISSN) ; Pishkenari, H. N ; Meghdari, A ; Sharif University of Technology
2006
Abstract
This paper presents a recursive approach for solving kinematic and dynamic problems in snake-like robots using Kane's equations. An n-link model with n-nonholonomic constraints is used as the snake robot model in our analysis. The proposed algorithm which is used to derive kinematic and dynamic equations recursively, enhances the computational efficiency of our analysis. Using this method we can determine the number of additions and multiplications as a function of n. The proposed method is compared with the Lagrange and Newton-Euler's method in three different aspects: Number of operations, CPU time and error in the computational procedures. © 2006 Cambridge University Press
A recursive approach for analysis of snake robots using Kane's equations
, Article DETC2005: ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, Long Beach, CA, 24 September 2005 through 28 September 2005 ; Volume 7 B , 2005 , Pages 855-861 ; 0791847446 (ISBN) ; Pishkenari, H. N ; Meghdari, A ; Sharif University of Technology
2005
Abstract
This paper presents a recursive approach for solving kinematic and dynamic problem in snake-like robots using Kane's equations. An n-link model with n-nonholonomic constraints is used as the snake robot model in our analysis. The proposed algorithm which is used to derive kinematic and dynamic equations recursively enhances the computational efficiency of our analysis. Using this method we can determine the number of additions and multiplications as a function of n. The proposed method is compared with the Lagrange and Newton-Euler's method in three different aspects: Number of operations, CPU time and error in the computational procedures. Copyright © 2005 by ASME
Optimal agent framework: a novel, cost-effective model articulation to fill the integration gap between agent-based modeling and decision-making
, Article Complexity ; Volume 2021 , 2021 ; 10762787 (ISSN) ; Khaleghparast, S ; Eshghi, K ; Sharif University of Technology
Hindawi Limited
2021
Abstract
Making proper decisions in today's complex world is a challenging task for decision makers. A promising approach that can support decision makers to have a better understanding of complex systems is agent-based modeling (ABM). ABM has been developing during the last few decades as a methodology with many different applications and has enabled a better description of the dynamics of complex systems. However, the prescriptive facet of these applications is rarely portrayed. Adding a prescriptive decision-making (DM) aspect to ABM can support the decision makers in making better or, in some cases, optimized decisions for the complex problems as well as explaining the investigated phenomena. In...
Analytical prediction of panel flutter using unsteady potential flow
, Article Journal of Aircraft ; Volume 40, Issue 4 , 2003 , Pages 805-807 ; 00218669 (ISSN) ; Esfahanian, V ; Haddadpour, H ; Sharif University of Technology
American Inst. Aeronautics and Astronautics Inc
2003
Abstract
An analytical procedure for supersonic flutter analysis of two-dimensional panels was developed using unsteady potential flow aerodynamic theory. The local spatial influence was considered as an integral over the plate area. The U-g method was used for flutter prediction. Results indicate a stabilizing effect of the unsteady potential flow aerodynamics theory compared to the quasi-steady first-order piston theory
A survey of human interactive proof systems
, Article International Journal of Innovative Computing, Information and Control ; Volume 6, Issue 3 , 2010 , Pages 855-874 ; 13494198 (ISSN) ; Shirali Shahreza, M ; Sharif University of Technology
2010
Abstract
Nowadays, a great amount of information is circulated through the Internet. Some of them exclusively belong to a special group of users and require protection and safeguarding against unauthorized access. To this end, a category of systems called HIP (Human Interactive Proof) are designed to distinguish between various groups of users. An important task on the Internet websites is registration. Some hackers write programs to make fake registration that waste the resources of the web sites or even stop them from providing services. Therefore, human users should be distinguished from computer programs. CAPTCHA (Completely Automatic Public Turing Test to Tell Computer and Human Apart) methods...
Spoken CAPTCHA: a CAPTCHA system for blind users
, Article 2009 Second ISECS International Colloquium on Computing, Communication, Control, and Management, CCCM 2009, Sanya, 8 August 2009 through 9 August 2009 ; Volume 1 , 2009 , Pages 221-224 ; 9781424442461 (ISBN) ; Abolhassani, H ; Sameti, H ; Shirali Shahreza, M. H ; Yangzhou University; Guangdong University of Business Studies; Wuhan Institute of Technology; IEEE SMC TC on Education Technology and Training; IEEE Technology Management Council ; Sharif University of Technology
2009
Abstract
Today, the Internet is used to offer different services to users. Most of these services are designed for human users, but unfortunately some computer programs are designed which abuse these services. CAPTCHA (Completely Automated Public Turing test to tell Computers and Human Apart) systems are designed to automatically distinguish between human users and computer programs and block such computer programs. Most of current CAPTCHA methods are using visual patterns and hence blind users cannot use them. In this paper, we propose a new CAPTCHA method which is designed for blind people. In this method, a small sound clip is played for the user and he/she is asked to say a word. Then the user...
CAPTCHA for children
, Article 2008 IEEE International Conference on System of Systems Engineering, SoSE 2008, Monterey, CA, 2 June 2008 through 4 June 2008 ; 2008 ; 9781424421732 (ISBN) ; Shirali Shahreza, M ; Sharif University of Technology
2008
Abstract
In some websites it is necessary to distinguishing between human users and computer programs which is known as CAPTCHA (Completely Automated Public Turing test to tell Computers and Human Apart). CAPTCHA methods are mainly based on the weak points of OCR systems and using them are undesirable to human users. In this paper a method has been presented for distinguishing between human users and computer programs on the basis of choice of an object shown on the screen. In this method some objects are chosen randomly and the pictures of these topics are downloaded from the Internet. Then after applying some effects such as rotation, all of the pictures are shown on the screen. Then we ask the...