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    Stock market index prediction using artificial neural network

    , Article Journal of Economics, Finance and Administrative Science ; Volume 21, Issue 41 , 2016 , Pages 89-93 ; 20771886 (ISSN) Hedayati Moghaddam, A ; Hedayati Moghaddam, M ; Esfandyari, M ; Sharif University of Technology
    Elsevier Doyma  2016
    Abstract
    In this study the ability of artificial neural network (ANN) in forecasting the daily NASDAQ stock exchange rate was investigated. Several feed forward ANNs that were trained by the back propagation algorithm have been assessed. The methodology used in this study considered the short-term historical stock prices as well as the day of week as inputs. Daily stock exchange rates of NASDAQ from January 28, 2015 to 18 June, 2015 are used to develop a robust model. First 70 days (January 28 to March 7) are selected as training dataset and the last 29 days are used for testing the model prediction ability. Networks for NASDAQ index prediction for two type of input dataset (four prior days and nine... 

    A rapid and sensitive HPLC-fluorescence method for determination of mirtazapine and its two major metabolites in human plasma

    , Article Iranian Journal of Pharmaceutical Research ; Volume 13, Issue 3 , Summer 2014 , Pages 853-862 Lavasani, H ; Giorgi, M ; Sheikholeslami, B ; Hedayati, M ; Rouini, M. R ; Sharif University of Technology
    Summer 2014
    Abstract
    A rapid and sensitive HPLC method has been developed for the quantification of mirtazapine (MRZ), a noradrenergic and specific serotonergic inhibitor antidepressant (NaSSA) and its two major metabolites N-desmethyl mirtazapine (NDM) and 8-hydroxymirtazapine (8-OHM) in human plasma. The separation was achieved using Chromolith C18 column and a mobile phase of acetonitrile: phosphate buffer (pH = 3, 20:80, v/v) in isocratic mode at a flow rate of 2 mL/min. A fluorescence detector was set at 290 and 350 nm for excitation and emission, respectively. Zolpidem was used as the internal standard. Liquid-liquid extraction was applied for sample clean up. All analytes were eluted in less than 5... 

    Battery cell dynamic modeling using the RC equivalent circuit for RTDS frameworks

    , Article 47th Annual Conference of the IEEE Industrial Electronics Society, IECON 2021, 13 October 2021 through 16 October 2021 ; Volume 2021-October , 2021 ; 9781665435543 (ISBN) Larijani, M. R ; Zolghadri, M ; Hedayati Kia, S ; El Hajjaji, A ; Sharif University of Technology
    IEEE Computer Society  2021
    Abstract
    This paper introduces a straightforward technique for parameters estimation of the RC equivalent circuit model of a battery cell with the main aim of its implementation in real-time digital simulator frameworks. The RC model parameters are precisely estimated by the analysis of the battery cell voltage curve during relaxation time using the pulse current test. In this regard, Least-squares fitting is used to mitigate the error of the battery cell voltage response, which leads to a precise estimation of the RC model parameters as a function of the state-of-charge. Exponential and Gaussian functions are utilized to define the resistances and the capacitances in the RC model respectively based... 

    Hybrid anisotropic pentamode mechanical metamaterial produced by additive manufacturing technique

    , Article Applied Physics Letters ; Volume 117, Issue 6 , 2020 Mohammadi, K ; Movahhedy, M. R ; Shishkovsky, I ; Hedayati, R ; Sharif University of Technology
    American Institute of Physics Inc  2020
    Abstract
    Pentamode metamaterials are a type of extremal designer metamaterials, which are able to demonstrate extremely high rigidity in one direction and extremely high compliance in other directions. Pentamodes can, therefore, be considered as building blocks of exotic materials with any arbitrarily selected thermodynamically admissible elasticity tensor. The pentamode lattices can then be envisioned to be combined to construct intermediate extremal materials, such as quadramodes, trimodes, and bimodes. In this study, we constructed several primary types of anisotropic pentamode lattices (with midpoint positioning of 10%, 15%, 20%, 25%, 30%, 35%, and 42% of the main unit cell diagonal) and then... 

    MIMO SAR Ground Moving Target Indication via Compressed Sensing

    , M.Sc. Thesis Sharif University of Technology Hedayati, Reza (Author) ; Mashhadi, Saeed (Supervisor)
    Abstract
    Synthetic Aperture Radar (SAR) is a coherent imaging technique capable of generating fine resolution images from long term standoff ranges, either day or night. The use of multiple antennas for SAR is referred to as multichannel SAR or Multiple-Input Multiple-Output(MIMO) SAR and offers the additional abilities to perform height estimation of the ground, improve the resolution and suppress undesired interferences. Ground moving target indication (GMTI) is the one that we explored in this research. Since the pattern of moving target in imaging zone is sparse, we can use compressed sensing for reducing computational complexity caused by additional channels. In our thesis, after modelling the... 

    Assessment study of shunt FACTS devices for improving dynamic behavior of induction motors

    , Article Sixth International Conference on Power Electronics and Drive Systems, PEDS 2005, Kualu Lumpur, 28 November 2005 through 1 December 2005 ; Volume 2 , 2005 , Pages 1352-1355 ; 0780392965 (ISBN); 9780780392960 (ISBN) Hedayati, M ; Oraee, H ; Sharif University of Technology
    2005
    Abstract
    An assessment study of two different shunt FACTS devices for compensating disturbances due to voltage variation in power systems is presented in this paper. Namely, Static Compensator (STATCOM) and Static Var Compensator (SVC) are Considered in this study. Eigen Value analysis and nonlinear time domain simulations for starting motor, motor in load varying state and short circuit on motor terminals show that STATCOM DC Voltage regulation has a better performance Compared to that of SVC. The result that will be presented in the paper will prove the superiorly of STATCOM over SVC in increasing motor speeding up and improving system voltage profile particularly at starting. © 2005 IEEE  

    Series solution of entropy generation toward an isothermal flat plate

    , Article Thermal Science ; Volume 16, Issue 5 , 2012 , Pages 1289-1295 ; 03549836 (ISSN) Malvandi, A ; Ganji, D. D ; Hedayati, F ; Kaffash, M. H ; Jamshidi, M ; Sharif University of Technology
    2012
    Abstract
    The steady 2-D boundary layer flow over a flat plate is studied analytically by homotopy perturbation method to analyze the entropy generation inside the boundary layer with constant wall temperature. By the transformations of go-verning equations including continuity, momentum, and energy by similarity va-riables, a dimensionless equation for entropy generation inside the boundary layer is obtained. The effects of important parameters such as Reynolds and Eck-ert numbers are investigated and the physical interpretations of the results are explained in details  

    A new method for finding core locations of extensive air showers

    , Article Astrophysical Journal ; Volume 727, Issue 2 , 2011 ; 0004637X (ISSN) Hedayati Kh., H ; Anvari, A ; Bahmanabadi, M ; Samimi, J ; Khakian Ghomi, M ; Sharif University of Technology
    Institute of Physics Publishing  2011
    Abstract
    Analysis of an extensive air shower (EAS) detected by surface arrays highly depends on the determination of core locations. Here we present a new method to find the core location of an EAS that, unlike the common methods, does not depend on the lateral distribution function and uses arrival times of secondary particles. This method improves the accuracy of finding the core location of a low-energy EAS in the internal parts of an array, in comparison with common methods  

    A new simple method for the analysis of extensive air showers

    , Article Astroparticle Physics ; Volume 34, Issue 9 , 2011 , Pages 699-704 ; 09276505 (ISSN) Hedayati Kh., H ; Anvari, A ; Bahmanabadi, M ; Samimi, J ; Khakian Ghomi, M ; Sharif University of Technology
    2011
    Abstract
    The most important goal of studying an extensive air shower is to find the energy, mass and arrival direction of its primary cosmic ray. In order to find these parameters, the core position and arrival direction of the shower should be determined. In this paper, a new method for finding core location has been introduced that utilizes trigger time information of particle detectors. We have also developed a simple technique to reconstruct the arrival direction. Our method is not based upon density-sensitive detectors which are sensitive to the number of crossing particles and is also independent of lateral distribution models. This model has been developed and examined by the analysis of... 

    A novel tunable UWB pulse design for narrowband interference suppression implemented in BiCMOS technology

    , Article Proceedings - IEEE International Symposium on Circuits and Systems, 24 May 2009 through 27 May 2009, Taipei ; 2009 , Pages 405-408 ; 02714310 (ISSN); 9781424438280 (ISBN) Hedayati, H ; Fotowat Ahmady, A ; Sharif University of Technology
    2009
    Abstract
    The unique properties of modified Hermite pulses is utilized to develop a novel pulse technique for Ultra Wideband (UWB) communications. The proposed method increases the bandwidth of the pulse up to 10 GHz and overcomes the coexistence problem of UWB and vulnerable narrowband systems through suppressing narrowband interference. Consequently it improves the range of UWB communications by increasing the power, without disturbing the narrowband systems. The pulse technique is implemented in high frequency pulse generation circuits and could be fully integrated in BiCMOS process. The nulls of the frequency response are tuned to be located in a definite narrowband system with the number of the... 

    Semi-empirical modelling of hydraulic conductivity of clayey soils exposed to deionized and saline environments

    , Article Journal of Contaminant Hydrology ; Volume 249 , 2022 ; 01697722 (ISSN) Hedayati Azar, A ; Sadeghi, H ; Sharif University of Technology
    Elsevier B.V  2022
    Abstract
    Clay liners are widely used as porous membrane barriers to control solute transport and to prevent the leakage of leachate both in horizontal and vertical flow scenarios, such as the isolated base and ramps of sanitary landfills. Despite the primary importance of saturated hydraulic conductivity in a reliable simulation of fluid flow through clay barriers, there is no model to predict hydraulic conductivity of clayey soils permeated with saline aqueous solutions because most of the current models were developed for pure water. Therefore, the main motivation behind this study is to derive semi-empirical models for simulating the hydraulic conductivity of clayey soils in the presence of... 

    Optimization of the size of scintillation detectors in order to use in an array of 20 detectors which is going to be placed in the Sharif University of Technology

    , Article Proceedings of the 32nd International Cosmic Ray Conference, ICRC 2011, 11 August 2011 through 18 August 2011, Beijing ; Volume 3 , 2011 , Pages 40-43 Pezeshkian, Y ; Mortazavi Moghaddam, S ; Hedayati, H ; Bahmanabadi, M ; Khalaj, P ; Sharif University of Technology
    Institute of High Energy Physics  2011
    Abstract
    As a primary step of establishment of an extensive air shower array consisting 20 scintillation detectors we optimized an individual detector. Square shaped scintillators are placed under a metal pyramid Light Enclosure with a photomultiplier tube (PMT) at the vertex of it. A set of experiments are performed to optimize the height of light enclosures by comparing 4 different heights 0.1, 0.2, 0.3 and 0.4 m. These experiments are supported by a Monte Carlo simulation of detection process. In this article, by considering experimental and simulation results we concluded that 20 cm is an optimum height for light enclosures  

    Assessment of fiber-reinforcement and foam-filling in the directional energy absorption performance of a 3D printed accordion cellular structure

    , Article Composite Structures ; Volume 297 , 2022 ; 02638223 (ISSN) Farrokhabadi, A ; Mahdi Ashrafian, M ; Behravesh, A. H ; Kaveh Hedayati, S ; Sharif University of Technology
    Elsevier Ltd  2022
    Abstract
    This paper presents an evaluation of two distinct techniques to improve energy absorption capability of an accordion cellular structure with close-to-zero Poisson's ratio. For this purpose, fiber-reinforcement and foam-filling methods were employed to address the material enhancement and to obtain light and tough structures with high specific energy absorption. Employing an innovated additive manufacturing based on material extrusion process, specimens of glass fiber-reinforced PLA were produced in both in-plane directions to compare with the un-reinforced counterpart. In continue, some of the 3D printed samples were strengthened by means of polyurethane foam in their hollow structure. The... 

    Vibration Control of Micro-Satellite Shelves Using Shpae Memory Alloy

    , M.Sc. Thesis Sharif University of Technology Hedayati Dezfuli, Farshad (Author) ; Abedian, Ali (Supervisor)
    Abstract
    Dynamic properties such as the natural frequency of a structure have a significant role in the design process. The importance of this consideration is because of resonance. In this case, the amplitude of the vibration is magnified to levels that may lead to a catastrophic event. While the usual design process depends on the collected experiences and statistical data, a developing trend is to implement smart technologies to develop smart structures that are capable of self-monitoring, diagnostics and repair. Smart material components such as shape memory alloys (SMAs) and piezoelectric ceramics are increasingly being used by vibration control practitioners. Shape memory alloys are applied as... 

    Membership Service in a Distributed High Performance Virtual Computing System

    , M.Sc. Thesis Sharif University of Technology Hedayati Goudarzi, Mohammad (Author) ; Ghodsi, Mohammad (Supervisor)
    Abstract
    Today with the development of te?nology, human ?allenges and problems have become even more complicated. In a way that as time went by the need for higher processing power to solve these problems has increased. High performance computers, are a category of computers whi? are used to solve su? problems. In the last two decade, distributed systems have become the most common way of gaining high performance. Here, Virtualization, an old te?nology whi? has revived in the last decade, providing spectacular features like isolation, migration, ease of management and creating opportunities like virtual clusters has proved to facilitate distributed processing. With the improvement of virtualizer’s... 

    Coordinated Tuning of Power System Stabilizer in Iran Power Grid for Damping Local and InterArea Oscilation

    , M.Sc. Thesis Sharif University of Technology Hedayati Shahidani, Mohsen (Author) ; Parniani, Mostafa (Supervisor)
    Abstract
    Power systems aredynamic and complex systems that are always subject to continuous changes and disturbance. Power system stability is a requirement for its satisfactory utilization. High speed Automatic voltage controllers with high gain tend to deteriorate both the electromechanical oscillation damping and small signal stability margin. Power system stabilizer (PSS) is a complementary controller that uses exciter voltage reference modulation to improve the electromechanical oscillation damping and stability margin. Optimal operation of PSS requires appropriate tuning according to the grid and power plant characteristics. In a largepower grid, absence or improper tuning of PSSs may cause one... 

    Investigation of Multiple Elastic Contacts of Dissimilar Materials in Partial Slip Regime Using a Numerical Method

    , M.Sc. Thesis Sharif University of Technology Hedayati, Ehsan (Author) ; Adib Nazari, Saeed (Supervisor)
    Abstract
    Modeling of contact is a important problem in word science, so a lot of method presented by researchers .
    In practical industry, if members of contact have complex shape or large deformation, analytical method can not solve the problem and use numerical method.
    This method by using ansys , first analyze one-area contact and compare between numerical result and analitical result, then analyze two-area contact between two body with vertical force, and compare result with considering effect of slip and target surface.
    Finaly to analyze a practical multiple contact problem, use modeling of tyre and road surface partial slip, and compare between ansys result with experimental result ,... 

    MIMO SAR ground moving target indication via compressed sensing

    , Article 26th Iranian Conference on Electrical Engineering, ICEE 2018, 8 May 2018 through 10 May 2018 ; 2018 , Pages 398-403 ; 9781538649169 (ISBN) Hedayati, R ; Mashhadi, S ; Vahedi, P ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    Abstract
    Synthetic aperture radar (SAR) systems are so popular in aerial imaging because of their high resolution. Ground moving target indication (GMTI) is one of the most challenging problems in this field. The use of multiple antennas in transmit and receive is an innovative idea that can overcome the limitations of SAR systems. In this paper, after modelling the received signal and focusing it, we propose an algorithm for GMTI with the use of compressed sensing. The proposed algorithm has low complexity compared to similar algorithms. Simulation results show that this approach is accurate in estimation of positions and velocities of moving targets. © 2018 IEEE  

    An Intelligent Triangular Pattern Recognition in Stock Price Charts

    , M.Sc. Thesis Sharif University of Technology Hedayati, Emadeddin (Author) ; Fazli, Mohammad Amin (Supervisor)
    Abstract
    Stock price patterns are a technical analysis approach to forecast future trends with tremendous practical benefits. However, the current algorithms solely rely on machine learning techniques and deep neural networks which could be a problem in countries where data sets such as these are not available. We propose an algorithm based on geometry and mathematics for this problem, leading to an O(n^3logn + n^2k) complexity, where k is the number of triangular patterns  

    Modeling and parallel computation of the non-linear interaction of rigid bodies with incompressible multi-phase flow

    , Article Computers and Mathematics with Applications ; Volume 72, Issue 4 , 2016 , Pages 1055-1065 ; 08981221 (ISSN) Malvandi, A ; Ghasemi, A. M ; Nikbakhti, R ; Ghasemi, A. R ; Hedayati, F ; Sharif University of Technology
    Elsevier Ltd  2016
    Abstract
    A computational tool is developed to capture the interaction of solid object with two-phase flow. The full two-dimensional Navier–Stokes equations are solved on a regular structured grid to resolve the flow field. The level set and the immersed boundary methods are used to capture the free surface of a fluid and a solid object, respectively. A two-step projection method along with Multi-Processing (OpenMP) is employed to solve the flow equations. The computational tool is verified based on numerical and experimental data with three scenarios: a cylinder falling into a rectangular domain due to gravity, transient vertical oscillation of a cylinder by releasing above its equilibrium position,...