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    A Semi-Supervised Algorithms for Clustering Microarray Data

    , M.Sc. Thesis Sharif University of Technology Eslamzadeh, Habibollah (Author) ; Mahdavi Amiri, Nezamoddin (Supervisor) ; Madadkar Sobhani, Armin (Supervisor)
    Abstract
    Microarray which is also known as Biochip is a flat substrate of glass with the size of 1 ×1 cm on which a numerous number of biosensors are placed in an array format. Microarray DNAs are used to measure expression level of thousands of genes. Repeating these experiments in different conditions can result in patterns of expression. After preparation, the florescent sample is hybridized with the sensors of microarray surface and fluoresce intensities of the spots are measured by a special camera called CCD. The obtained pictures are examined by a computer and the spot lights converted into numerical data by image processing algorithms. Putting these numbers into matrices of size m×n is... 

    Optimization of Heat Recovery and Water Capture System from Boiler Flue Gas

    , M.Sc. Thesis Sharif University of Technology Armin, Bahman (Author) ; Saboohi, Yadollah (Supervisor)
    Abstract
    Thermal energy and water in flue gases varies with the type of fuel and thermal conversion system. Flue gas temperature is maintained in the range of 140 (℃) to 200 (℃) and it is subject to the sulfur content of the fuel. Vapor content of the flue gas is in the range of 10%_20% of volumetric flow. Considerable part of vapor may be recovered which can be used as cooling water make up. There are various means and methods for water capture and heat recovery which includes shell-tube heat exchanger among others. Selection of appropriate material and heat exchanger is conditioned by corrosion, temperature of flue gas and it’s economic feasibility. Identification of an optimal design of... 

    Design and Manufacturing of a Multi Functional Device For Experimental Fatigue Test and Special Facilities for Symmetric and Anti Symmetric Loading on Gears

    , M.Sc. Thesis Sharif University of Technology Armin, Amir (Author) ; Durali, Mohammad (Supervisor)
    Abstract
    The goal of this research is design and manufacturing of a device for fatigue test and 3D crack propagation in spur gear roots. Clearly it should be able to test gear in oscillated bending load and control the amplitude and period of loading. Designed setup in this project using a electro hydraulic actuator can do it up to 50 KN and 10 Hz in amplitude and frequency and a PLC controls it during the test time. System can load gears symmetric or anti symmetric and simulate the effect of shaft misalignments, bearing damage and gear production tolerances on the gear loading. System completely designed, built and tested during this project and using experimental data, its performance was... 

    New drift detection method for data streams

    , Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) ; Volume 6943 LNAI , 2011 , Pages 88-97 ; 03029743 (ISSN) ; 9783642238567 (ISBN) Sobhani, P ; Beigy, H ; Sharif University of Technology
    2011
    Abstract
    Correctly detecting the position where a concept begins to drift is important in mining data streams. In this paper, we propose a new method for detecting concept drift. The proposed method, which can detect different types of drift, is based on processing data chunk by chunk and measuring differences between two consecutive batches, as drift indicator. In order to evaluate the proposed method we measure its performance on a set of artificial datasets with different levels of severity and speed of drift. The experimental results show that the proposed method is capable to detect drifts and can approximately find concept drift locations  

    New ensemble method for classification of data streams

    , Article 2011 1st International eConference on Computer and Knowledge Engineering, ICCKE 2011, Mashhad, 13 October 2011 through 14 October 2011 ; 2011 , Pages 264-269 ; 9781467357135 (ISBN) Sobhani, P ; Beigy, H ; Sharif University of Technology
    2011
    Abstract
    Classification of data streams has become an important area of data mining, as the number of applications facing these challenges increases. In this paper, we propose a new ensemble learning method for data stream classification in presence of concept drift. Our method is capable of detecting changes and adapting to new concepts which appears in the stream  

    Duplex stainless steel/martensitic steel dissimilar resistance spot welding: Microstructure-properties relationships

    , Article Welding Journal ; Volume 98, Issue 9 , 2019 , Pages 263S-272S ; 00432296 (ISSN) Sobhani, S ; Pouranvari, M ; Sharif University of Technology
    American Welding Society  2019
    Abstract
    This paper addresses the phase transformations and mechanical performance of dissimilar resistance spot welds between 2304 duplex stainless steel (DSS) and 1.2-GPa martensitic (MS) advanced high-strength steel (AHSS). The solidification mode and transformation path of the fusion zone (FZ) were analyzed. The key metallurgical feature of the FZ was the formation of a duplex microstructure consisting of delta ferrite and martensite. The FZ size at the sheet/sheet interface was the critical factor controlling the fraction of pullout failure during the partial thickness-partial pullout mode, the load-bearing capacity, and the energy absorption capability of the DSS/MS dissimilar resistance spot... 

    Data Stream Classification in Presence of Concept Drift Using Ensemble Learning

    , M.Sc. Thesis Sharif University of Technology Sobhani, Parinaz (Author) ; Beigy, Hamid (Supervisor)
    Abstract
    Traditional classification techniques of machine learning assume that data have stationary distributions. This assumption for recent challenges where tremendous amount of data are generated at unprecedented rates with evolving patterns, is not true anymore. Classification of data streams has become an important area of machine learning, as the number of applications facing these challenges increases. Examples of such data streams applications include text streams, surveillance video streams, credit card fraud detection, market basket analysis, information filtering, computer security, etc. An appropriate method for such problems should adapt to drifting concepts by revising and refining the... 

    Scientific and Philosophical Foundations of “Multiverse” Idea

    , Ph.D. Dissertation Sharif University of Technology Sobhani, Alireza (Author) ; Golshani, Mehdi (Supervisor)
    Abstract
    Isn’t our universe ,which includes everything that is causally connected to us, a tiny and negligible part of wider and diverse “multiple universes”? Although the multiverse idea has been considered by scientists recently, it had been discussed by philosophers and theologians in the past.
    Many of our physical theories,whether being accepted like General Relativity, or speculative like string theory, lead naturally to the multiverse idea .The idea of multiverse is also brought forth to take care of the fine tuning observed in cosmology, in connection with the so – called anthropic principle.
    This idea appeared in order to answer to some problems of quantum mechanics, string theory... 

    Welding Metallurgy and Weldability of Martensitic Advanced High Strength Steel and Duplex Stainless Steels during Resistance Spot Welding

    , M.Sc. Thesis Sharif University of Technology Sobhani, Saeed (Author) ; Pouranvari, Majid (Supervisor)
    Abstract
    Duplex stainless steels and advanced high strength steels are both known as new materials in automobile industry applications. Process of resistance spot welding is the main process in welding of auto-body structures. Hence investigating the welding metallurgy and weldability of similar and dissimilar joints of duplex stainless steels and advanced high strength steel are crucial. The purpose of this study is to analyse the relationship between welding process and geometric characteristic of weld nugget, phase transformations of Weld nugget and heat affected zone, mechanical properties (i.e force bearing capacity and energy absorption capability) and failure mode (interfatial or pullout). in... 

    Energy-aware Task Mapping and Scheduling in Mixed-criticality Multi-core Embedded Systems

    , M.Sc. Thesis Sharif University of Technology Sobhani, Hoora (Author) ; Hessabi, Shaahin (Supervisor)
    Abstract
    Mixed-criticality embedded systems, as the next-generation of safety-critical systems, are increasingly employed in industry due to consolidating functionalities with varying criticality levels onto the same computing platform. Also, cost reduction and performance improvement encourage adoption of multicore platforms in these systems. Technology scaling, battery-supplied design and heavy computation in mixed-criticality systems necessitates employing energy management techniques. Due to the degrading effects of these techniques on the system’s reliability, reducing energy consumption without sacrificing the reliability requirement is a vital challenge in mixed-criticality systems, in... 

    Increasing Operating Range of Wideband Reconnaissance Receivers, by Using Antenna Arrays

    , Ph.D. Dissertation Sharif University of Technology Sobhani, Ghasem (Author) ; Behnia, Fereidoon (Supervisor)
    Abstract
    Passive wideband reconnaissance receivers, listen to the radio and radar signals in the environment and estimate their important parameters such as direction of arrival (DOA). The wideband attribute for these receivers is to refer to their ability to receive wideband signals.Due to the use of processing gain, LPI radars reduce their transmitted signal power to see and not to be seen. On the other hand reconnaissance receivers can not have much processing gain, because they do not know the nature of the transmitted signal; Therefore, to increase the operational range of these systems, it is necessary to increase the signal to noise power ratio (SNR). This thesis examines the use of antenna... 

    Wake interference of two identical oscillating cylinders in tandem: An experimental study

    , Article Ocean Engineering ; Volume 166 , 2018 , Pages 311-323 ; 00298018 (ISSN) Armin, M ; Khorasanchi, M ; Day, S ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    This study aims to assess the impact of the spacing between cylinders on their dynamic behaviour. Observations during this experiment have helped to identify the effect of spacing on excitation mechanism of each cylinder as well as establishing the relationship between cylinders response and the spacing between them. Arrays of cylindrical Structures in close proximity are common in variety of engineering structures, particularly in the offshore industry. If the cylinders are flexible, and are subject to excitation from fluid flow, then the dynamics is influenced by complex interactions between the cylinders, dependent on a variety of parameters. Two cylinders were flexibly mounted in tandem... 

    The effect of nanoparticles on spontaneous imbibition of brine into initially oil-wet sandstones

    , Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Volume 41, Issue 22 , 2019 , Pages 2746-2756 ; 15567036 (ISSN) Sobhani, A ; Ghasemi Dehkordi, M ; Sharif University of Technology
    Taylor and Francis Inc  2019
    Abstract
    In this paper, the effect of silica nanoparticles on oil production due to the spontaneous imbibition of brine into oil-wet sandstones has been studied. The imbibed fluids were NaCl 3 wt. % solutions containing various concentrations of nanoparticles and the recovered oil for each solution was compared. The results revealed that nanoparticles yielded more oil recovery. Nanofluid was used after brine imbibition, and the oil recovery increased from 17.8% to 40% while in the case of using the same nanofluid as the first imbibed fluid the oil recovery was 53%. Also, the results indicated that the oil recovery depends on nanoparticle concentrations. © 2019, © 2019 Taylor & Francis Group, LLC  

    Ranking of hazardous road locations in two-lane two-way Rural roads with no crash record

    , Article ATRF 2011 - 34th Australasian Transport Research Forum ; 2014 Habibian, M ; Mesbah, M ; Sobhani, A ; Sharif University of Technology
    2014
    Abstract
    Crash data availability is a significant requirement for identifying hazardous roads. However, for roads with poor data sets or no crash record, a method is needed to find and rank road segments independent of the crash records. In this paper, an auditing based methodology is proposed to determine the hazardous locations. A Rural road is investigated by decomposing it first into six elements, and then into safety factors corresponding to each element. The elements are: straight segments, horizontal and vertical curves, bridges, tunnels, merges and intersections, and side road land use. The relative contribution of the elements to the safety of a road segment is determined using the... 

    Creation of twisted terahertz waves carrying orbital angular momentum via a plasma vortex

    , Article Journal of Physics D: Applied Physics ; Volume 49, Issue 29 , 2016 ; 00223727 (ISSN) Sobhani, H ; Rooholamininejad, H ; Bahrampour, A ; Sharif University of Technology
    Institute of Physics Publishing  2016
    Abstract
    In this paper a new method for generating twisted terahertz radiation is proposed. The generation of twisted terahertz radiation in a plasma vortex, where the plasma density profile has helical structure, is investigated. The method is described on the basis of angular momentum exchange between plasma vortex and laser beam. The interaction of the vortex plasma and photons causes the laser angular momentum to change. Twisted terahertz radiation is produced at the beat frequency of laser and electron plasma waves. In this process, for Gaussian laser modes, the angular momentum of terahertz wave derives from the plasma vortex, while for the Laguerre-Gaussian it originates in the difference in... 

    Effect of pump depletion and cross-focusing on twisted terahertz radiation generation

    , Article Physics of Plasmas ; Volume 24, Issue 2 , 2017 ; 1070664X (ISSN) Sobhani, H ; Dehghan, M ; Dadar, E ; Sharif University of Technology
    American Institute of Physics Inc  2017
    Abstract
    In this paper, the pump depletion and cross-focusing effects on the generation of twisted terahertz radiation are investigated. Based on the beating of two Laguerre-Gaussian lasers in a radial plasma channel, a twisted terahertz radiation can be produced. In the presence of pump depletion, the lasers power is consumed. So, the ponderomotive force nonlinearity decreases and the output terahertz field approaches to a saturation value. Under competition between the diffraction and nonlinearity effects, the amplitude of laser beam width oscillation grows. When the incident laser beams have non-similar topological charge numbers, the normalized generated terahertz amplitude is low and the pump... 

    The stereoselective synthesis of the tetrahydrothiopyranolr ,Y'-blindole skeletons via tandem reaction of indoline- r-thiones to Baylis-Hillman adduct acetates & Silica-Supported DABCO-tribromide: A New, Versatile and Recyclable Catalyst for the Chemoselective Oxidation of Sulfides to Sulfoxides and Oxidative Coupling of Thiols into Disulfides

    , M.Sc. Thesis Sharif University of Technology Sobhani, Maryam (Author) ; Matloubi Moghaddam, Firouz (Supervisor)
    Abstract
    We have reported a new and efficient synthesis of tetrahydrothiopyrano [2,3-b]indole skeletons via unique tandem reaction of indoline-2-thiones to Baylis-Hillman adduct acetates. This protocol is a very mild and simple method for construction heterocycles in a one-step process. This is a convenient and diastereoselective synthesis of methyl 4-aryl-2,3,4,9-tetrahydrothiopyrano[2,3-b]indole-3-carboxylate systems in the presence of K2CO3 in acetonitrile. The major benefits of the current study are the one-pot procedure, high yields and diastereoselectivity, short reaction times and the similarity of the products to the biologically active moieties.
    In addition 1, 4-diazabicyclo [2.2.2]... 

    Pupil Detection and Eye Tracking

    , M.Sc. Thesis Sharif University of Technology Sobhani, Elahe (Author) ; Babaie Zadeh, Massoud (Supervisor)
    Abstract
    About a century, “Eye Tracking” has been studied, and it has two definitions: • The process of measuring the point of gaze (where one is looking). • The process of measuring the motion of an eye relative to the head. Eye tracking technology has been used in many fields such as psychology. However, applications of this technology has been recently considered in marketing, computer interfacing, entertainment, training and so forth. Since pupil is a distinc area in eye images, pupil detection is one of the effective solutions of eye tracking. In most of the pupil detection approaches, the edge points of the pupil contour are detected firstly, and then the optimal ellipse is fitted to them.... 

    On the development of a nonlinear time-domain numerical method for describing vortex-induced vibration and wake interference of two cylinders using experimental results

    , Article Nonlinear Dynamics ; 2021 ; 0924090X (ISSN) Armin, M ; Day, S ; Karimirad, M ; Khorasanchi, M ; Sharif University of Technology
    Springer Science and Business Media B.V  2021
    Abstract
    A nonlinear mathematical model is developed in the time domain to simulate the behaviour of two identical flexibly mounted cylinders in tandem while undergoing vortex-induced vibration (VIV). Subsequently, the model is validated and modified against experimental results. Placing an array of bluff bodies in proximity frequently happens in different engineering fields. Chimney stacks, power transmission lines and oil production risers are few engineering structures that may be impacted by VIV. The coinciding of the vibration frequency with the structure natural frequency could have destructive consequences. The main objective of this study is to provide a symplectic and reliable model capable... 

    An integrated two-level demand-side management game applied to smart energy hubs with storage

    , Article Energy ; Volume 206 , 2020 Sobhani, S. O ; Sheykhha, S ; Madlener, R ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    Energy hubs, an important component of future energy networks employing distributed demand-side management, can play a key role in enhancing the efficiency and reliability of power grids. In power grids, energy hub operators need to optimally schedule the consumption, conversion, and storage of available resources based on their own utility functions. In sufficiently large networks, scheduling an individual hub can affect the utility of the other energy hubs. In this paper, the interaction between energy hubs is modeled as a congestion game. Each energy hub operator (player) participates in a dynamic energy pricing market and tries to maximize his/her own payoff when satisfying energy...