Search for: mirzazad-barijough--k
0.065 seconds

    Application of generalized neuron in electricity price forecasting

    , Article 2009 IEEE Bucharest PowerTech: Innovative Ideas Toward the Electrical Grid of the Future, 28 June 2009 through 2 July 2009, Bucharest ; 2009 ; 9781424422357 (ISBN) Mirzazad Barijough, S ; Sahari, A. A ; Sharif University of Technology
    With recent deregulation in electricity industry, price forecasting has become the basis for this competitive market. The precision of this forecasting is essential in bidding strategies. So far, the artificial neural networks which can find an accurate relation between the historical data and the price have been used for this purpose. One major problem is that, they usually need a large number of training data and neurons either for complex function approximation and data fitting or classification and pattern recognition. As a result, the network topology has a significant impact on the network computational time and ability to learn and also to generate unseen data from training data. To... 

    A predictive approach to control frequency instabilities in a wide area system

    , Article 2009 IEEE/PES Power Systems Conference and Exposition, PSCE 2009, Seattle, WA, 15 March 2009 through 18 March 2009 ; 2009 ; 9781424438112 (ISBN) Mirzazad Barijough, S ; Mashhuri, M ; Ranjbar, A. M ; Sharif University of Technology
    Wide-area monitoring and control system complements the classical protection systems and overcomes their drawbacks. In such systems a dynamic view of power system, using synchronized measurements in short time intervals, smaller than 20ms, is available. This new kind of system's information provides a novel preventive control action to prevent system's large disturbances. This paper proposes a new method to prevent frequency instabilities immediately after a disturbance occurs in a system. Based on online measurements sent by phasor measurement units, a single machine equivalent model including the governors' effect is computed. An accurate frequency prediction is done based on this novel... 

    Implementation-aware model analysis: The case of buffer-throughput tradeoff in streaming applications

    , Article Proceedings of the ACM SIGPLAN Conference on Languages, Compilers, and Tools for Embedded Systems (LCTES), 18 June 2015 through 19 June 2015 ; Volume 2015-June , 2015 , Pages 108-117 ; 9781450332576 (ISBN) Mirzazad Barijough, K ; Hashemi, M ; Khibin, V ; Ghiasi, S ; Sharif University of Technology
    Association for Computing Machinery  2015
    Models of computation abstract away a number of implementation details in favor of well-defined semantics. While this has unquestionable benefits, we argue that analysis of models solely based on operational semantics (implementation oblivious analysis) is unfit to drive implementation design space exploration. Specifically, we study the tradeoff between buffer size and streaming throughput in applications modeled as synchronous data flow (SDF) graphs. We demonstrate the inherent inaccuracy of implementation-oblivious approach, which only considers SDF operational semantic. We propose a rigorous transformation, which equips the state of the art buffer-throughput tradeoff analysis technique... 

    Implementation-aware model analysis: The case of buffer-throughput tradeoff in streaming applications

    , Article ACM SIGPLAN Notices ; Volume 50, Issue 5 , May , 2015 , Pages 103-112 ; 15232867 (ISSN) Barijough, K. M ; Hashemi, M ; Khibin, V ; Ghiasi, S ; Sharif University of Technology
    Association for Computing Machinery  2015
    Models of computation abstract away a number of implementation details in favor of well-defined semantics. While this has unquestionable benefits, we argue that analysis of models solely based on operational semantics (implementationoblivious analysis) is unfit to drive implementation design space exploration. Specifically, we study the tradeoff between buffer size and streaming throughput in applications modeled as synchronous data flow (SDF) graphs. We demonstrate the inherent inaccuracy of implementationoblivious approach, which only considers SDF operational semantic. We propose a rigorous transformation, which equips the state of the art buffer-throughput tradeoff analysis technique... 

    A fine-grained configurable cache architecture for soft processors

    , Article 18th CSI International Symposium on Computer Architecture and Digital Systems, 7 October 2015 through 8 October 2015 ; 2015 ; 9781467380232 (ISBN) Biglari, M ; Mirzazad Barijough, K ; Goudarzi, M ; Pourmohseni, B ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    The ever increasing density and performance of FPGAS, has increased the importance and popularity of soft processors. The growing gap between the speed of processors and memories can partly be compensated through memory hierarchy. Since memory accesses follow a non-uniform distribution, and vary from one application to another, variable set-associative cache architectures have emerged. In this paper, a novel cache architecture, primarily aimed at soft processors, is proposed to address the variable access demands of applications, through dynamically configurable line-associativity, with no memory overhead. The FPGA implementation of the proposed architecture achieves an average miss count... 

    Recent advances in ageing of 7xxx series aluminum alloys: A physical metallurgy perspective

    , Article Journal of Alloys and Compounds ; Volume 781 , 2019 , Pages 945-983 ; 09258388 (ISSN) Azarniya, A ; Taheri, A. K ; Taheri, K. K ; Sharif University of Technology
    Elsevier Ltd  2019
    Al-Zn-Mg-Cu alloys (7xxx series Al alloys) are extensively used for their superior mechanical and corrosion performance. These properties are microstructure-sensitive and highly dependent on the formation, growth and coarsening of precipitates. To date, a wide variety of ageing procedures have been developed to tailor the evolved microstructures so as to yield a good combination of mechanical capacity and corrosion resistance of 7xxx series Al alloys. Among these methods, isothermal ageing, multi-stage ageing, non-isothermal ageing, retrogression and re-ageing (RRA), and stress ageing (i.e. creep ageing) are the most significant. In the present review, all of these approaches are... 

    Stiffness and strength estimation of damaged unreinforced masonry walls using crack pattern

    , Article Journal of Earthquake Engineering ; Volume 26, Issue 2 , 2022 , Pages 837-856 ; 13632469 (ISSN) Dolatshahi, K. M ; Beyer, K ; Sharif University of Technology
    Taylor and Francis Ltd  2022
    After an earthquake, the residual stiffness and strength of structural elements are typically estimated based on a qualitative visual inspection of cracks that is prone to error. In this paper a new approach is proposed to automatically estimate the updated stiffness and strength of damaged unreinforced masonry walls by characterization of crack patterns by a mathematical index. It is shown that structural and textural fractal dimensions of a crack pattern reflect the extent of cracking and the type of cracking or crushing, i.e., whether the cracks pass through joints or whether bricks have been damaged and crushed. Using results of six quasi-static cyclic tests on unreinforced brick masonry... 

    Influence of heat treatment and aging on microstructure and mechanical properties of Mg-1.8Zn-0.7Si-0.4Ca alloy

    , Article Materialwissenschaft und Werkstofftechnik ; Volume 50, Issue 2 , 2019 , Pages 187-196 ; 09335137 (ISSN) Shaeri, M ; Taheri, K. K ; Taheri, A. K ; Shaeri, M. H ; Sharif University of Technology
    Wiley-VCH Verlag  2019
    In order to optimize the aging treatment of Mg-1.8Zn-0.7Si-0.4Ca alloy, different times and temperatures of solid solution and age hardening were applied to the alloy specimens. Microstructures and mechanical properties of the specimens were investigated using the optical microscopy, field emission scanning electron microscopy equipped with an energy dispersive x-ray spectrometer, x-ray diffraction, hardness, and shear punch tests. The lowest hardness and strength were achieved by solution treating of the alloy at 500 °C for 8 h, presenting the optimal condition for solution treatment of the alloy. The microstructural examinations revealed three different precipitates consisting of CaMgSi,... 

    The nonlinear diffusion bandwidth: A simple tool for optimizing dispersion maps

    , Article Optical Transmission, Switching, and Subsystems IV, Gwangju, 5 September 2006 through 7 September 2006 ; Volume 6353 I , 2006 ; 0277786X (ISSN) ; 0819464481 (ISBN); 9780819464484 (ISBN) Bunge, C. A ; Fischer, J. K ; Louchet, H ; Jamshidi, K ; Petermann, K ; Sharif University of Technology
    The concept of a nonlinear transfer function of a fibre-optic communication link is reviewed. Also an approximation of the nonlinear transfer function is introduced, which allows to define an equivalent single-span model of a dispersion-managed multi-span system. In this paper we will show its limits of validity and try to extent these limits by enhancing the theoretical model. In this respect we will discuss the impact of dispersion precompensation and show the influence of residual dispersion per span, number of spans and local dispersion on transmission systems with on-off keying and differential phase-shift keying modulation formats. This approach allows fast assessment of the... 

    Nickel-based nanosheets array as a binder free and highly efficient catalyst for electrochemical hydrogen evolution reaction

    , Article International Journal of Hydrogen Energy ; Volume 47, Issue 82 , 2022 , Pages 34887-34897 ; 03603199 (ISSN) Faraji, H ; Hemmati, K ; Mirabbaszadeh, K ; Sharif University of Technology
    Elsevier Ltd  2022
    Hydrogen technology through water electrolyzer systems has attracted a great attention to overcome the energy crisis. So, rationally designed non-noble metal based-electrocatalysts with high activity and durability can lead to high performance water electrolyzer systems and high purity hydrogen generation. Herein, a facile two-step method: hydrothermal and electrodeposition, respectively, are developed to decorate highly porous three-dimensional binder-free structure NiFeO/NiO nanosheets array on Ni foam (NiFeO/NiO/NF) with robust adhesion as a high-performance electrode for Hydrogen Evolution Reaction (HER). The electrodeposition process applied after the initial hydrothermal process... 

    New operational transconductance amplifiers using current boosting

    , Article Midwest Symposium on Circuits and Systems ; 2012 , Pages 109-112 ; 15483746 (ISSN) ; 9781467325264 (ISBN) Noormohammadi, M ; Lazarjan, V. K ; HajSadeghi, K ; Sharif University of Technology
    New techniques for Class-AB Operational Transconductance Amplifiers (OTAs) are presented. These new techniques are two topologies based on current boosting in class-AB stage which achieve considerable improvement of Slew Rate and Gain-Bandwidth while maintaining the same power consumption as the conventional design. Circuit level analysis and simulation results of proposed circuits in 0.18μm CMOS technology for gain, GBW, slew rate, and settling time are presented to prove the effectiveness of the proposed design method  

    Ranking of technology transfer barriers in developing countries; case study of Iran's biotechnology industry

    , Article IEEE International Conference on Industrial Engineering and Engineering Management, 6 December 2011 through 9 December 2011, Singapore ; 2011 , Pages 1602-1606 ; 21573611 (ISSN) ; 9781457707391 (ISBN) Yazdani, K ; Rashvanlouei, K. Y ; Ismail, K ; Sharif University of Technology
    In this paper, first we shall define a list of technology transfer barriers in the biotechnology field through interviews and literature reviews. Next, we shall categorize them into four major categories of technology, and at last introduce all of the hypotheses on the existence of relationship between each part of technology and failure in the technology transfer process. Questionnaires consisting of two parts were created and handed out to all of the specialists and biotechnology idea-holders in the Iranian National Research center of Biotechnology, Lidco Co, Iran Pastor Institute, Biotechnology Department of University of Tehran, etc. Going on, we've evaluated the factors' validity... 

    A coupled adjoint formulation for non-cooled and internally cooled turbine blade optimization

    , Article Applied Thermal Engineering ; Volume 105 , 2016 , Pages 327-335 ; 13594311 (ISSN) Zeinalpour, M ; Mazaheri, K ; Chaharlang Kiani, K ; Sharif University of Technology
    Elsevier Ltd  2016
    Most researches on the application of the adjoint method in turbine blade design are concentrated on the aerodynamic shape optimization without considering the heat transfer to/from the blade material. In this study, the adjoint method is extended to the conjugate heat transfer problems in which the viscous flow field is coupled to heat transfer in the solid region. Introducing a new adjoint variable in the solid domain, a heat adjoint equation is derived which is coupled with the energy adjoint equation in the fluid zone at the fluid/solid interface. The detailed mathematical description associated with the derivation of the heat adjoint equation with corresponding boundary conditions are... 

    A self-organizing multi-model ensemble for identification of nonlinear time-varying dynamics of aerial vehicles

    , Article Proceedings of the Institution of Mechanical Engineers. Part I: Journal of Systems and Control Engineering ; Volume 235, Issue 7 , 2021 , Pages 1164-1178 ; 09596518 (ISSN) Emami, S. A ; Ahmadi, K. K. A ; Sharif University of Technology
    SAGE Publications Ltd  2021
    This article presents a novel identification approach which can deal with nonlinear and time-varying characteristics of complex dynamic systems, especially an aerial vehicle in the entire flight envelope. A set of local sub-models are first developed at different operating points of the system, and subsequently a self-organizing multi-model ensemble is introduced to aggregate the outputs of the local models as a single model. The number of employed local models in the proposed multi-model ensemble is optimized using a novel self-organizing approach. Also, wavelet neural networks, which combine both the universal approximation property of neural networks and the wavelet decomposition... 

    Simple SPR-based colorimetric sensor to differentiate Mg2+ and Ca2+ in aqueous solutions

    , Article Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy ; Volume 268 , 2022 ; 13861425 (ISSN) Amirjani, A ; Salehi, K ; Sadrnezhaad, S. K ; Sharif University of Technology
    Elsevier B.V  2022
    L-tryptophan functionalized AgNPs were successfully fabricated using a one-pot synthesis method and assessed as a colorimetric probe for rapid and accurate determination of Mg2+ ions. The developed sensor showed a selective response towards Mg2+ with no interference from Ca2+ in the wide concentration range of 1–200 µM. The sensor's response was optimized in the pH range of 9–10, which can be attributed to the protonation of amine groups and their interaction with Mg2+ ions. The stability and selectivity of the sensor were examined in different salt (NaCl) and other metal ions, respectively. The L-tryptophan-AgNPs sensor detected Mg2+ with the limit of detection of 3 µM, which is way lower... 

    Micro-optoelectromechanical systems accelerometer based on intensity modulation using a one-dimensional photonic crystal

    , Article Applied Optics ; Volume 55, Issue 32 , 2016 , Pages 8993-8999 ; 1559128X (ISSN) Sheikhaleh, A ; Abedi, K ; Jafari, K ; Gholamzadeh, R ; Sharif University of Technology
    OSA - The Optical Society  2016
    In this paper, we propose what we believe is a novel sensitive micro-optoelectromechanical systems (MOEMS) accelerometer based on intensity modulation by using a one-dimensional photonic crystal. The optical sensing system of the proposed structure includes an air-dielectric multilayer photonic bandgap material, a laser diode (LD) light source, a typical photodiode (1550 nm) and a set of integrated optical waveguides. The proposed sensor provides several advantages, such as a relatively wide measurement range, good linearity in the whole measurement range, integration capability, negligible cross-axis sensitivity, high reliability, and low air-damping coefficient, which results in a wider... 

    On the formation of intermetallics during the furnace brazing of pure titanium to 304 stainless steel using Ag (30-50%)-Cu filler metals

    , Article Materials and Manufacturing Processes ; Volume 25, Issue 11 , 2010 , Pages 1333-1340 ; 10426914 (ISSN) Shafiei, A ; Abachi, P ; Dehghani, K ; Pourazarang, K ; Sharif University of Technology
    In the present work, the effect of brazing pa rameters on the properties of the brazed joint of pure titanium and 304 stainless steel (304SS) was investigated. Three different Ag-Cu filler metals were used, while the temperature and time of brazing were in the range of 800-950°C and 5-45 minutes, respectively. The microstructural observations show that, depending on the brazing conditions, different intermetallic phases such as CuTi2, CuTi, Cu3Ti4, and FeTi were formed at the phases interface. Based on the microstructural observations, a model was developed to characterize the formation of phases at the interfaces and brazed joint. The results show that, while some phases may form during the... 

    Influence of load history on the force-displacement response of in-plane loaded unreinforced masonry walls

    , Article Engineering Structures ; Volume 152 , 2017 , Pages 671-682 ; 01410296 (ISSN) Valentin Wilding, B ; Dolatshahi, K. M ; Beyer, K ; Sharif University of Technology
    Empirical drift capacity models for in-plane loaded unreinforced masonry (URM) walls are derived from results of quasi-static cyclic shear-compression tests. The experimentally determined drift capacities are, however, dependent on the applied demand, i.e., on the loading protocol that is used in the test. These loading protocols differ between test campaigns. The loading protocols applied in tests are also different from the displacement histories to which URM walls are subjected in real earthquakes. In the absence of experimental studies on the effect of loading histories on the wall response, this article presents numerical simulations of modern unreinforced clay block masonry walls that... 

    Numerical study on factors that influence the in-plane drift capacity of unreinforced masonry walls

    , Article Earthquake Engineering and Structural Dynamics ; Volume 47, Issue 6 , 2018 , Pages 1440-1459 ; 00988847 (ISSN) Dolatshahi, K. M ; Nikoukalam, M. T ; Beyer, K ; Sharif University of Technology
    John Wiley and Sons Ltd  2018
    Displacement-based assessment procedures require as input reliable estimates of the deformation capacity of all structural elements. For unreinforced masonry (URM) walls, current design codes specify the in-plane deformation capacity as empirical equations of interstory drift. National codes differ with regard to the parameters that are considered in these empirical drift capacity equations, but the inhomogeneity of datasets on URM wall tests renders it difficult to validate the hypotheses with the currently available experimental data. This paper contributes to the future development of such empirical relationships by investigating the sensitivity of the drift capacity to the shear span,... 

    Shear-compression tests of URM walls: various setups and their influence on experimental results

    , Article Engineering Structures ; Volume 156 , February , 2018 , Pages 472-479 ; 01410296 (ISSN) Wilding, B. V ; Dolatshahi, K. M ; Beyer, K ; Sharif University of Technology
    Elsevier Ltd  2018
    Current design codes provide empirical equations for the drift capacity of unreinforced masonry (URM) walls that are based on results of quasi-static cyclic shear-compression tests. Yet different experimental campaigns have used various approaches of imposing fixed-fixed boundary conditions at the wall top which may affect the test results. This article investigates, by means of numerical simulations, the influence of experimental setups on the force and drift capacities of in-plane loaded URM walls subjected to double-fixed conditions. It is shown that controlling the shear span or the top rotation while keeping the axial force constant leads to very similar results. Controlling the axial...