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    Deployment of multi-agent robotic systems in presence of obstacles

    , Article ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis, ESDA2010, 12 July 2010 through 14 July 2010, Istanbul ; Volume 5 , 2010 , Pages 7-12 ; 9780791849194 (ISBN) Soltani, A ; Sayyaadi, H ; Sharif University of Technology
    2010
    Abstract
    The deployment of multi-agent systems in presence of obstacle deals with autonomous motion of agents toward a specified target by sensing each other and boundaries of obstacles. In this paper, asynchronous, scalable, distributed algorithm is used to deploy agents. Boundaries of obstacles are modeled by virtual agents. Algorithm was implemented by solving continuous n-median problem called generalized Fermat-Weber problem. It is shown that deployment is performed when position of real agents are the geometric median of their Voronoi cells. Simulation results show the validity of the proposed algorithm very well  

    When pixels team up: Spatially weighted sparse coding for hyperspectral image classification

    , Article IEEE Geoscience and Remote Sensing Letters ; Volume 12, Issue 1 , Jan , 2015 , Pages 107-111 ; 1545598X (ISSN) Soltani Farani, A ; Rabiee, H. R ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    Abstract
    In this letter, a spatially weighted sparse unmixing approach is proposed as a front-end for hyperspectral image classification using a linear SVM. The idea is to partition the pixels of a hyperspectral image into a number of disjoint spatial neighborhoods. Since neighboring pixels are often composed of similar materials, their sparse codes are encouraged to have similar sparsity patterns. This is accomplished by means of a reweighted ℓ1 framework where it is assumed that fractional abundances of neighboring pixels are distributed according to a common Laplacian Scale Mixture (LSM) prior with a shared scale parameter. This shared parameter determines which endmembers contribute to the group... 

    Dynamic performance of concrete slabs reinforced with steel and GFRP bars under impact loading

    , Article Engineering Structures ; Volume 191 , 2019 , Pages 62-81 ; 01410296 (ISSN) Sadraie, H ; Khaloo, A ; Soltani, H ; Sharif University of Technology
    Elsevier Ltd  2019
    Abstract
    Reinforced concrete slabs are common structural elements that could be exposed to impact loading. Although use of reinforced concrete slabs and utilization of Fiber Reinforced Polymer (FRP) as alternative to traditional steel reinforcement slabs are growing, but the influence of various parameters on their response under impact loads is not properly evaluated. This study investigated the effect of rebar's material, amount and arrangement of reinforcements, concrete strength and slab thickness on dynamic behavior of reinforced concrete slabs using both laboratory experiments and numerical simulations. Performance of fifteen 1000 × 1000 mm concrete slabs, including two 75 mm thick plain slabs,... 

    Dynamic performance enhancement of RC slabs by steel fibers vs. externally bonded GFRP sheets under impact loading

    , Article Engineering Structures ; Volume 213 , 2020 Soltani, H ; Khaloo, A ; Sadraie, H ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    Recently, to improve the dynamic behavior of Reinforced Concrete (RC) slabs under impact load, the methods of externally bonding Glass Fiber Reinforced Polymer (GFRP) sheets to slab and internally reinforcing concrete by steel fibers have been proposed. Nevertheless, it is required to investigate the comparison between these two methods on response of RC slabs under impact loads. In this study, the influence of volume fraction of steel fibers, the number of GFRP sheet layers (one or two) and the arrangement of GFRP sheets (covering the whole or parts of surface), are examined. Performance of fourteen 1000 × 1000 × 75 mm concrete slabs including one plain slab, one steel RC slab, three steel... 

    Effect of surface contamination on the performance of a section of a wind turbine blade

    , Article 45th AIAA Aerospace Sciences Meeting 2007, Reno, NV, 8 January 2007 through 11 January 2007 ; Volume 19 , 2007 , Pages 13026-13036 ; 1563478900 (ISBN); 9781563478901 (ISBN) Soltani, M. R ; Birjandi, A. H ; Sharif University of Technology
    2007
    Abstract
    A series of low speed wind tunnel tests on a section of a 660 Kw wind turbine blade which is under constructer were conducted to examine the effects of distributed surface contamination on its performance characteristics. At first model was tested in the clean condition and after that it was tested with tree different types of roughness. The data shows that this particular airfoil is very sensitive to the applied surface roughness. For the contaminated model the roughness, 0.5mm height was distributed over the entire upper surface of the airfoil such that the distribution pattern was denser in the vicinity of the leading edge and thinner in the trailing edge area. Statistical data show that... 

    Contamination effects on the performance of a wind turbine blade section

    , Article 9th AIAA/ASME Joint Thermophysics and Heat Transfer Conference Proceedings, San Francisco, CA, 5 June 2006 through 8 June 2006 ; Volume 4 , 2006 , Pages 2801-2805 ; 1563478153 (ISBN); 9781563478154 (ISBN) Soltani, M. R ; Birjandi, A. H ; Sharif University of Technology
    2006
    Abstract
    A series of low speed wind tunnel tests on a section of a 660 Kw wind turbine blade were conducted to examine the effects of distributed surface contamination on its performance. The airfoil was a section of a wind turbine blade under construction. The performance of the section was measured in the following conditions: 1. Clean airfoil 2. Two types of zigzag roughness 3. Strip tape 4. Distributed contamination roughness Our preliminary data shows that the airfoil is very sensitive to the applied surface roughness. For the contamination model the roughness, 0.5mm height, is distributed over the entire upper surface of the airfoil. By putting the contamination roughness on the airfoil the... 

    Effect of electrodeposition time on the super-capacitive performance of electrodeposited MnO2 on g-C3N4 nanosheets

    , Article Journal of Alloys and Compounds ; Volume 904 , 2022 ; 09258388 (ISSN) Soltani, H ; Bahiraei, H ; Ghasemi, S ; Sharif University of Technology
    Elsevier Ltd  2022
    Abstract
    Herein, the effect of electrodeposition time on the super-capacitive performance of three-dimensional (3D) MnO2/g-C3N4 heterostructured electrodes was investigated. MnO2 nanoparticles were electrodeposited on the g-C3N4 nanosheets drop-casted on the Ni foam substrate. The microstructural analysis, carried out by FE-SEM and TEM, confirmed the homogeneous distribution of MnO2 nanoparticles on g-C3N4 nano-sheet layers. The electrochemical capacitive performances of the MnO2/g-C3N4 electrodes were evaluated by cyclic voltammetry (CV), galvanostatic charge/discharge tests, and electrochemical impedance spectra (EIS). The obtained results suggested that the supercapacitor (SC) performance of all... 

    Analytical prediction of panel flutter using unsteady potential flow

    , Article Journal of Aircraft ; Volume 40, Issue 4 , 2003 , Pages 805-807 ; 00218669 (ISSN) Soltani, N ; 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  

    Experimental investigation of leading-edge roughness effects on stationary crossflow instability of a swept wing

    , Article Scientia Iranica ; Volume 20, Issue 3 , 2013 , Pages 524-534 ; 10263098 (ISSN) Soltani, M. R ; Masdari, M ; Damghani, H ; Sharif University of Technology
    2013
    Abstract
    Wind tunnel experiments were conducted to evaluate surface pressure distribution over a semi span swept wing with a sweep angle of 33°. The wing section has a laminar flow airfoil similar to that of the NACA 6-series. The tests were conducted at speeds ranging from 50 to 70 m/s with and without surface roughness. Surface static pressure was measured on the wing upper surface at three different chordwise rows located at the inboard, middle, and outboard stations. The differences between pressure distributions on the three sections of the wing were studied and the experimental results showed that roughness elements do not influence the pressure distribution significantly, except at the inboard... 

    A progressive multi-scale fatigue model for life prediction of laminated composites

    , Article Journal of Composite Materials ; Volume 51, Issue 20 , 2017 , Pages 2949-2960 ; 00219983 (ISSN) Hosseini Kordkheili, S.A ; Toozandehjani, H ; Soltani, Z ; Sharif University of Technology
    SAGE Publications Ltd  2017
    Abstract
    This article presents a multi-scale progressive micro-mechanical fatigue model. The model employs fundamental equation of the kinetic theory of fracture to calculate damage parameters of both fiber and matrix during cyclic loading. In order to adapt the equation, required material coefficients of the constituents can be achieved from fatigue test results of longitudinal and transverse unidirectional composites, only. Sharing stress capacities of fiber and matrix are determined using a modified progressive micro-mechanical bridging model in the presence of damage. The damage parameters in the constituents are calculated employing two different equivalent scalars. However, during sinusoidal... 

    Semi-spatiotemporal fMRI brain decoding

    , Article Proceedings - 2013 3rd International Workshop on Pattern Recognition in Neuroimaging, PRNI 2013 ; 2013 , Pages 182-185 ; 9780769550619 (ISBN) Kefayati, M. H ; Sheikhzadeh, H ; Rabiee, H. R ; Soltani Farani, A ; Sharif University of Technology
    2013
    Abstract
    Functional behavior of the brain can be captured using functional Magnetic Resonance Imaging (fMRI). Even though fMRI signals have temporal and spatial structures, most studies have neglected the temporal structure when inferring mental states (brain decoding). This has two main side effects: 1. Degradation in brain decoding performance due to lack of temporal information in the model, 2. Inability to provide temporal interpretability. Few studies have targeted this issue but have had less success due to the burdening challenges related to high feature-to-instance ratio. In this study, a novel model for incorporating temporal information while maintaining a low feature-to-instance ratio, is... 

    A content-based deep intrusion detection system

    , Article International Journal of Information Security ; 2021 ; 16155262 (ISSN) Soltani, M ; Siavoshani, M. J ; Jahangir, A. H ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2021
    Abstract
    The growing number of Internet users and the prevalence of web applications make it necessary to deal with very complex software and applications in the network. This results in an increasing number of new vulnerabilities in the systems, and leading to an increase in cyber threats and, in particular, zero-day attacks. The cost of generating appropriate signatures for these attacks is a potential motive for using machine learning-based methodologies. Although there are many studies on using learning-based methods for attack detection, they generally use extracted features and overlook raw contents. This approach can lessen the performance of detection systems against content-based attacks... 

    A content-based deep intrusion detection system

    , Article International Journal of Information Security ; Volume 21, Issue 3 , 2022 , Pages 547-562 ; 16155262 (ISSN) Soltani, M ; Siavoshani, M. J ; Jahangir, A. H ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2022
    Abstract
    The growing number of Internet users and the prevalence of web applications make it necessary to deal with very complex software and applications in the network. This results in an increasing number of new vulnerabilities in the systems, and leading to an increase in cyber threats and, in particular, zero-day attacks. The cost of generating appropriate signatures for these attacks is a potential motive for using machine learning-based methodologies. Although there are many studies on using learning-based methods for attack detection, they generally use extracted features and overlook raw contents. This approach can lessen the performance of detection systems against content-based attacks... 

    Effect of surface contamination on the performance of a section of a wind turbine blade

    , Article Scientia Iranica ; Volume 18, Issue 3 B , 2011 , Pages 349-357 ; 10263098 (ISSN) Soltani, M. R ; Birjandi, A. H ; Seddighi Moorani, M ; Sharif University of Technology
    2011
    Abstract
    A series of low speed wind tunnel tests were conducted on a section of a 660 kW wind turbine blade to examine the effects of distributed surface contamination on its performance characteristics. The selected airfoil was tested with a clean surface, two types of zigzag roughness, strip tape roughness and distributed contamination roughness. The straight and zigzag leading edge roughness models simplify the contamination results in an early turbulence transition. In this study, surface contamination was simulated by applying 0.5 mm height roughness over the entire upper surface of the airfoil. The distribution density varied from the leading edge to the trailing edge of the model. Our data... 

    An experimental study of buzz instability in an axisymmetric supersonic inlet

    , Article Scientia Iranica ; Volume 18, Issue 2 B , 2011 , Pages 241-249 ; 10263098 (ISSN) Soltani, M. R ; Farahani, M ; Asgari Kaji, M. H ; Sharif University of Technology
    2011
    Abstract
    An experimental study was carried out on an axisymmetric supersonic inlet with external compression. The scope of this study was to investigate the general characteristics of the inlet buzz under various design and off-design conditions. The model was equipped with accurate and high frequency pressure sensors and the tests were conducted at Mach numbers varying from 1.8 to 2.5, at various angles of attack, and at different mass flow rates. Shadowgraph flow visualization, together with a high speed camera, was used to capture the external shock structure in front of the inlet. Frequencies of buzz were obtained from both the shadowgraph pictures and analysis of the pressure data. The amplitude... 

    Spatial-aware dictionary learning for hyperspectral image classification

    , Article IEEE Transactions on Geoscience and Remote Sensing ; Volume 53, Issue 1 , July , 2015 , Pages 527-541 ; 01962892 (ISSN) Soltani Farani, A ; Rabiee, H. R ; Hosseini, S. A ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    Abstract
    This paper presents a structured dictionary-based model for hyperspectral data that incorporates both spectral and contextual characteristics of spectral samples. The idea is to partition the pixels of a hyperspectral image into a number of spatial neighborhoods called contextual groups and to model the pixels inside a group as members of a common subspace. That is, each pixel is represented using a linear combination of a few dictionary elements learned from the data, but since pixels inside a contextual group are often made up of the same materials, their linear combinations are constrained to use common elements from the dictionary. To this end, dictionary learning is carried out with a... 

    Impact of reduced frequency on the time lag in pressure distribution over a supercritical airfoil in a pitch-pause-return motion

    , Article Chinese Journal of Aeronautics ; Volume 32, Issue 2 , 2019 , Pages 243-252 ; 10009361 (ISSN) Eslami, H. Z ; Davari, A. R ; Soltani, M. R ; Sharif University of Technology
    Chinese Journal of Aeronautics  2019
    Abstract
    Effects of reduced frequency, stop angle, and pause duration have been studied on a thin supercritical airfoil undergoing a pitch-pause-return motion, which is one of the classic maneuvers introduced by the AIAA Fluid Dynamics Technical Committee. Experiments were conducted in a low-speed wind tunnel at both a constant mean angle of attack and an oscillation amplitude with a reduced frequency ranging from 0.01 to 0.12. The desired stop angles of the airfoil were set to occur during the upstroke motion. The unsteady pressure distribution on the airfoil was measured for below, near, and beyond static stall conditions. Results showed that the reduced frequency and stop angle were the dominant... 

    Surface contamination effects on the 2-D and unsteady wind turbine blade section performance

    , Article 25th AIAA Applied Aerodynamics Conference, 2007, Miami, FL, 25 June 2007 through 28 June 2007 ; Volume 2 , 2007 , Pages 795-801 ; 10485953 (ISSN) ; 1563478986 (ISBN); 9781563478987 (ISBN) Soltani, M. R ; Birjandi, A. H ; Goreishi, S. M ; Sharif University of Technology
    2007
    Abstract
    A series of unsteady low speed wind tunnel tests on a section of a 660 Kw wind turbine blade under construction were conducted to examine the effects of distributed surface contamination on its performance characteristics. Our data shows that the airfoil is very sensitive to the applied surface roughness. Results show that contamination decreases static maximum lift coefficient more than 40 percent. In the dynamic test this effect is the same and is about 38 percent. Contamination decreases the width of the dynamic diagrams loop such and leads to the smooth stall on the airfoil  

    Oscillation Frequency and Reynolds Number Effects on a Contaminated Wind Turbine Blade Section

    , Article 25th AIAA Applied Aerodynamics Conference, 2007, Miami, FL, 25 June 2007 through 28 June 2007 ; Volume 2 , 2007 , Pages 1203-1207 ; 10485953 (ISSN) ; 1563478986 (ISBN); 9781563478987 (ISBN) Soltani, M. R ; Birjandi, A. H ; Goreishi, S. M ; Sharif University of Technology
    2007
    Abstract
    A series of unsteady low speed wind tunnel tests on a section of a 660 Kw wind turbine blade which is under construction were conducted to examine the effects of distributed surface contamination on its performance characteristics. Model was tested at three mean angles of attack, 5, 10 and 18 degrees at the fixed oscillation domain of 5 degrees. Results show that contamination decreases the maximum lift coefficient more than 40 percent. However Reynolds number and oscillation frequency increase, have a positive effect on the maximum lift coefficient in the contaminated model and it decreased the difference between maximum lift coefficient in the clean airfoil and the contaminated one  

    Unsteady supersonic aerodynamics based on BEM, including thickness effects in aeroelastic analysis

    , Article Journal of Fluids and Structures ; Volume 19, Issue 6 , 2004 , Pages 801-813 ; 08899746 (ISSN) Soltani, N ; Esfahanian, V ; Haddadpour, H ; Behbahani Nejad, M ; Sharif University of Technology
    2004
    Abstract
    A general three-dimensional aeroelastic solver is developed based on coupled finite element and boundary element methods and applied to investigate the flutter boundaries in supersonic flows. The boundary element method is applied to three-dimensional unsteady supersonic potential flow as the aerodynamic model and coupled with the finite element method for structural modelling, in order to construct the system of aeroelastic equations. The aeroelastic equations are solved for the flutter prediction using the frequency domain approach. Flutter boundaries for two types of wing planforms at supersonic speeds are determined and compared with the existing experimental results and previous...