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    The synergistic effect of surface topography and sustained release of TGF-β1 on myogenic differentiation of human mesenchymal stem cells

    , Article Journal of Biomedical Materials Research - Part A ; Volume 104, Issue 7 , 2016 , Pages 1610-1621 ; 15493296 (ISSN) Moghadasi Boroujeni, S ; Mashayekhan, S ; Vakilian, S ; Ardeshirylajimi, A ; Soleimani, M ; Sharif University of Technology
    John Wiley and Sons Inc  2016
    Abstract
    A combination of topographical cues and controlled release of biochemical factors is a potential platform in controlling stem cells differentiation. In this study the synergistic effect of nanotopography and sustained release of biofunctional transforming growth factor beta 1 (TGF-β1) on differentiation of human Wharton's Jelly-derived mesenchymal stem cell (hWJ-derived UC-MSCs) toward myogenic lineage was investigated. In order to achieve a sustained release of TGF-β1, this factor was encapsulated within chitosan nanoparticles. Afterwards the aligned composite mats were fabricated using poly-E-caprolacton (PCL) containing TGF-β1-loaded chitosan nanoparticles and poly-L-lactic acid (PLLA).... 

    Polar decomposition of the k-fold product of lebesgue measure on ℝ n

    , Article Bulletin of the Australian Mathematical Society ; Volume 85, Issue 2 , 2012 , Pages 315-324 ; 00049727 (ISSN) Moghadasi, S. R ; Sharif University of Technology
    2012
    Abstract
    The Blaschke-Petkantschin formula is a geometric measure decomposition of the q-fold product of Lebesgue measure on ℝ n. Here we discuss another decomposition called polar decomposition by considering ℝ n× ×ℝ n as n×k and using its polar decomposition. This is a generalisation of the Blaschke-Petkantschin formula and may be useful when one needs to integrate a function g:ℝ n××ℝ n→ℝ with rotational symmetry, that is, for each orthogonal transformation O,g(O(x1),O(xk))=g(x1,xk) . As an application we compute the moments of a Gaussian determinant. Copyright  

    Controllability of rolling bodies with regular surfaces

    , Article Journal of the Korean Mathematical Society ; Volume 53, Issue 4 , 2016 , Pages 725-735 ; 03049914 (ISSN) Moghadasi, S. R ; Sharif University of Technology
    Korean Mathematical Society  2016
    Abstract
    A pair of bodies rolling on each other is an interesting example of nonholonomic systems in control theory. There is a geometric condition equivalent to the rolling constraint which enables us to generalize the rolling motions for any two-dimensional Riemannian manifolds. This system has a five-dimensional phase space. In order to study the controllability of the rolling surfaces, we lift the system to a six-dimensional space and show that the lifted system is controllable unless the two surfaces have isometric universal covering spaces. In the non-controllable case there are some three-dimensional orbits each of which corresponds to an isometry of the universal covering spaces  

    Rolling of a body on a plane or a sphere: A geometric point of view

    , Article Bulletin of the Australian Mathematical Society ; Volume 70, Issue 2 , 2004 , Pages 245-256 ; 00049727 (ISSN) Moghadasi, S. R ; Sharif University of Technology
    Australian Mathematical Publishing Association  2004
    Abstract
    A pair of bodies rolling on each other is an interesting example of nonholonomic systems in control theory. Here the controllability of rolling bodies is investigated with a global approach. By using simple geometric facts, this problem has been completely solved in the special case where one of them is a plane or a sphere  

    Improved MPC algorithms for edit distance and ulam distance

    , Article 31st ACM Symposium on Parallelism in Algorithms and Architectures, SPAA 2019, 22 June 2019 through 24 June 2019 ; 2019 , Pages 31-40 ; 9781450361842 (ISBN) Boroujeni, M ; Seddighin, S ; Sharif University of Technology
    Association for Computing Machinery  2019
    Abstract
    Edit distance is one of the most fundamental problems in combinatorial optimization. Ulam distance is a special case of edit distance where no character is allowed to appear more than once in a string. Recent developments have been very fruitful for obtaining fast and parallel algorithms for both edit distance and Ulam distance. In this work, we present an almost optimal MPC algorithm for Ulam distance and improve MPC algorithms for edit distance. Our algorithm for Ulam distance is optimal in the sense that (1) the approximation factor of our algorithm is 1 + ϵ, (2) the round complexity of our algorithm is constant, (3) the total memory of our algorithm is almost linear (OH(n)), and (4)] the... 

    Optimal attitude consensus for multi rigid bodies network considered on the lie group SO(3) with connectivity preserving property

    , Article IET Control Theory and Applications ; Volume 16, Issue 11 , 2022 , Pages 1137-1153 ; 17518644 (ISSN) Mansourinasab, S ; Sojoodi, M ; Moghadasi, S. R ; Sharif University of Technology
    John Wiley and Sons Inc  2022
    Abstract
    This paper proposes distributed optimal attitude consensus control for single-integrator multi rigid bodies with undirected network evolving on Special Orthogonal Group SO(3) while simultaneously guarantees the connectivity preservation property for agents using descent gradient algorithm. Since by Use of the Euclidean distance on Lie group as a measure of the energy of the state does not define and preserve the topology of SO(3); besides, solving the Hamilton–Jacobi–Bellman equation in optimal control problems shows difficulty implementing Euclidean distances and limits the results for SO(3) configuration state spaces. As a result, in this paper, the generic distance on SO(3) associated to... 

    MEHRAB MAPS: One-dimensional piecewise nonlinear chaotic maps

    , Article International Journal of Bifurcation and Chaos ; Volume 22, Issue 5 , 2012 ; 02181274 (ISSN) Borujeni, S. E ; Eshghi, M ; Boroujeni, M. S ; Sharif University of Technology
    2012
    Abstract
    In this paper, we propose a new one-dimensional, two-segmental nonlinear map by combining tent, triangle and parabola curve functions. We call the proposed map, Mehrab map since its return maps shape is similar to an altar (which we call it "Mehrab"). Definition and properties of Mehrab map along with orbit diagrams, Lyapunov exponents, and its histograms are considered. To generate more uniform density function maps, two modified versions of the proposed Mehrab map are also defined. In the first modification of Mehrab map (FMM), vertical symmetry and transformation to the right are used. Sensitivity to initial condition and total chaotic range of FMM are medium. Probability density function... 

    Improved MPC algorithms for Edit distance and Ulam distance

    , Article IEEE Transactions on Parallel and Distributed Systems ; Volume 32, Issue 11 , 2021 , Pages 2764-2776 ; 10459219 (ISSN) Boroujeni, M ; Ghodsi, M ; Seddighin, S ; Sharif University of Technology
    IEEE Computer Society  2021
    Abstract
    Edit distance is one of the most fundamental problems in combinatorial optimization to measure the similarity between strings. Ulam distance is a special case of edit distance where no character is allowed to appear more than once in a string. Recent developments have been very fruitful for obtaining fast and parallel algorithms for both edit distance and Ulam distance. In this work, we present an almost optimal MPC (massively parallel computation) algorithm for Ulam distance and improve MPC algorithms for edit distance. Our algorithm for Ulam distance is almost optimal in the sense that (1) the approximation factor of our algorithm is $1+epsilon$1+ϵ, (2) the round complexity of our... 

    Hippocampal shape analysis in epilepsy using Laplace-Beltrami spectrum

    , Article 2011 19th Iranian Conference on Electrical Engineering, ICEE 2011, 17 May 2011 through 19 May 2011 ; May , 2011 , Page(s): 1 - 5 ; ISSN : 21647054 ; 9789644634284 (ISBN) Shishegar, R ; Soltanian Zadeh, H ; Moghadasi, S. R ; Sharif University of Technology
    2011
    Abstract
    Shape analysis plays an important role in many medical imaging studies. One of the recent shape analysis methods uses the Laplace Beltrami eigenvalues which is also used in this paper for global shape comparison of hippocampus of normal subjects and epileptic patients. Popularity of the Laplace Beltrami operator in this field is due to its isometry-invariance which avoids pre-processing steps like mapping, registration, and alignment. In addition, it is capable of revealing fine details in shapes that makes this method a good choice for deformation detecting purposes like epilepsy diagnosis. To examine capability of the proposed method, statistical analysis and two ways of classification,... 

    Improving the quality of active millimeter wave standoff imaging by incorporating the cross-polarized scattering wave

    , Article Optics Express ; Volume 29, Issue 20 , 2021 , Pages 32603-32614 ; 10944087 (ISSN) Shojaeian, S ; Ahmadi Boroujeni, M ; Hajitabarmarznaki, S ; Sharif University of Technology
    The Optical Society  2021
    Abstract
    In this paper, we study the feasibility of incorporating the cross-polarized scattered wave in active standoff millimeter-wave imaging in order to improve the edge detection and background suppression for metallic objects. By analyzing the scattering from a perfectly conducting (PEC) patch of a simple geometrical shape we show that the edge diffraction is the major source of cross-polarized scattering. A similar scattering behavior is also observed for a PEC patch placed on a dielectric medium. Hence, the cross-polarized scattered field conveys valuable information about the edges of the object. In addition, the cross-polarized scattering can be utilized to resolve the object from an... 

    Effects of Preheating and CO2 Dilution on Oxy-MILD Combustion of Natural Gas

    , Article Journal of Energy Resources Technology, Transactions of the ASME ; Volume 141, Issue 12 , 2019 ; 01950738 (ISSN) Moghadasi, M. H ; Riazi, R ; Tabejamaat, S ; Mardani, A ; Sharif University of Technology
    American Society of Mechanical Engineers (ASME)  2019
    Abstract
    Oxy-moderate or intense low-oxygen dilution (MILD) combustion, which is a novel combination of oxy-fuel technology and MILD regime, is numerically studied in the present work. The effects of external preheating and CO2 dilution level on the combustion field, emission, and CO formation mechanisms are investigated in a recuperative laboratory-scale furnace with a recirculating cross-flow. Reynolds-averaged Navier-Stokes (RANS) equations with eddy dissipation concept (EDC) model are employed to perform a 3-D simulation of the combustion field and the turbulence-chemistry interactions. In addition, a well-stirred reactor (WSR) analysis is conducted to further examine the chemical kinetics of... 

    1 + ϵ approximation of tree edit distance in quadratic time

    , Article 51st Annual ACM SIGACT Symposium on Theory of Computing, STOC 2019, 23 June 2019 through 26 June 2019 ; 2019 , Pages 709-720 ; 07378017 (ISSN); 9781450367059 (ISBN) Boroujeni, M ; Ghodsi, M ; Hajiaghayi, M ; Seddighin, S ; Sharif University of Technology
    Association for Computing Machinery  2019
    Abstract
    Edit distance is one of the most fundamental problems in computer science. Tree edit distance is a natural generalization of edit distance to ordered rooted trees. Such a generalization extends the applications of edit distance to areas such as computational biology, structured data analysis (e.g., XML), image analysis, and compiler optimization. Perhaps the most notable application of tree edit distance is in the analysis of RNA molecules in computational biology where the secondary structure of RNA is typically represented as a rooted tree. The best-known solution for tree edit distance runs in cubic time. Recently, Bringmann et al. show that an O(n2.99) algorithm for weighted tree edit... 

    Hippocampal shape analysis in the Laplace Beltrami feature space for temporal lobe epilepsy diagnosis and lateralization

    , Article Proceedings - International Symposium on Biomedical Imaging ; 2012 , Pages 150-153 ; 19457928 (ISSN) ; 9781457718588 (ISBN) Shishegar, R ; Gandomkar, Z ; Soltaman Zadeh, H ; Moghadasi, S. R ; Sharif University of Technology
    IEEE  2012
    Abstract
    Shape analysis plays an important role in many medical imaging studies. One of the recent shape analysis methods uses the Laplace Beltrami operator which is also used in this paper for hippocampal shape comparison. We proposed a feature vector which consists of size measures and shape descriptors based on Laplace Beltrami eigenvalues and eigenfunctions. The aforementioned feature space is utilised for automatic differentiating normal subjects from epileptic patients as well as distinguishing epileptic patients with left temporal lobe epilepsy (LTLE) from patients with right temporal lobe epilepsy (RTLE). Achieved results are diagnostic accuracy of 93% with 95% sensitivity and lateralization... 

    Static and dynamic behavior of foam stabilized by modified nanoparticles: Theoretical and experimental aspects

    , Article Chemical Engineering Research and Design ; Volume 158 , 2020 , Pages 114-128 Suleymani, M ; Ashoori, S ; Ghotbi, C ; Moghadasi, J ; Kharrat, R ; Sharif University of Technology
    Institution of Chemical Engineers  2020
    Abstract
    Gas flooding is a practical secondary scenario for enhanced oil recovery. Channeling and fingering of the injected gas are the major problems facing this technique. These challenges can be mitigated by the injection of gas as foam. However, foam stability influences the overall efficiency of the process, which could be improved by nanoparticles (NPs). This work provides a theoretical and experimental analysis of the NPs wettability effects on foam behavior, in both static and dynamic states. The treated calcite (CaCO3) NPs along with a cationic surfactant (HTAB) were used for this purpose. By comparison of theoretical and experimental data, it was shown that the foam stability in the... 

    Theoretical and experimental study of foam stability mechanism by nanoparticles: Interfacial, bulk, and porous media behavior

    , Article Journal of Molecular Liquids ; Volume 304 , 2020 Suleymani, M ; Ghotbi, C ; Ashoori, S ; Moghadasi, J ; Kharrat, R ; Sharif University of Technology
    Elsevier B.V  2020
    Abstract
    Foam flooding has been applied as a promising method in enhanced oil recovery to obviate the challenges of gas flooding such as fingering, channeling and overriding. However, long-term foam stability is crucial for mobility control. In this work, the effective mechanisms on foam stability in the presence of CaCO3 nanoparticles were assessed both theoretically and experimentally. The static and dynamic behaviors of cationic surfactant (HTAB) foam in the presence of CaCO3 nanoparticles with different hydrophobicity were evaluated. The CaCO3 nanoparticles were treated with a series of long-chain fatty acids to generate a range of wettability. Afterward, the underlying mechanisms were revealed... 

    Application of endurance time method in nonlinear seismic analysis of steel frames

    , Article Procedia Engineering ; Volume 14 , 2011 , Pages 3237-3244 ; 18777058 (ISSN) Riahi, H. T ; Estekanchi, H. E ; Seyedain Boroujeni, S ; Sharif University of Technology
    2011
    Abstract
    In Endurance Time (ET) method gradually intensifying acceleration functions are created in a manner that the linear and nonlinear response spectra of them, while being proportional to average of real earthquakes spectra, intensifies in a uniform manner with time. These functions are used as input functions for nonlinear time history analysis of structures and performance of structures is assessed based on the maximum time duration that they can meet the specified performance objectives. In this paper, application of the ET method in nonlinear seismic analysis of structures has been investigated. Numerical procedures and optimization techniques that are used for the production of acceleration... 

    Design and optimization of Gregorian-based reflector systems for thz imaging system optics

    , Article 4th West Asian Symposium on Optical and Millimeter-Wave Wireless Communications, WASOWC 2022, 12 May 2022 through 13 May 2022 ; 2022 ; 9781665409131 (ISBN) Koohi Ghamsari, M. H ; Ahmadi Boroujeni, M ; Babanejad, S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2022
    Abstract
    The application of reflector antenna configurations in designing the optical section of terahertz imaging systems has attracted great attention in recent years. The advantages of reflective optics in comparison with refractive optics is one of the main reasons for this trend. Specular reflection in a broad spectral range, no or little reflection and transmission loss, no chromatic aberration, and high reliability in high power applications configuration are just some of these advantages. In this paper, the optical performance of a modified off-axis aberrations-free Gregorian-based reflector antenna system is studied as an optical section of a terahertz imaging system. By applying a precise... 

    Forward and Inverse Problem of Seismic Waves

    , M.Sc. Thesis Sharif University of Technology Mojahedi, Mojtaba (Author) ; Moghadasi, Reza (Supervisor)
    Abstract
    Applying of seismic waves and analysing of its reflections is of effective ways in exploration of the internal structur of the Earth. In this method the Earth is considered as a elastic body that seismic waves are propagated in it. In this thesis the how of creation and propagation of seismic waves is modeld at first and then the inverse problem, exploration of the internal structure of the Earth from observed data, is considered  

    Trajectory Estimation of a Vehicle Using Stereo Cameras

    , M.Sc. Thesis Sharif University of Technology Eftekhar, Parham (Author) ; Moghadasi, Reza (Supervisor)
    Abstract
    Visual odometry(VO) is the process of estimating the egomotion of an agent(e.g., vehicle, human, and robot) using the input of a single or multiple cameras attached to it. Application domains include robotics, wearable computing, augmented reality, and automotive. The term was chosen for its similarity to wheel odometry, which incrementally estimates the motion of a vehicle by integrating the number of turns of its wheels over time. Likewise, VO operates by incrementally estimating the pose of the vehicle through examination of the changes that movements induces on the images of its onboard cameras. For the VO to work effectively, there should be sufficient illumination in the environment... 

    Ray Tracing Based on Reinforcement Learning

    , M.Sc. Thesis Sharif University of Technology Razavi, Mojtaba (Author) ; Moghadasi, Reza (Supervisor)
    Abstract
    We show that the equations of reinforcement learning and light transport simulation (rendering equation) are related integral equations. Based on this correspondence, a scheme to learn importance while sampling path space is derived. The new approach is demonstrated in a consistent ray tracing algorithm that uses reinforcement learning to progressively learn where light comes from. As using this information for importance sampling includes information about visibility, too, the number of light transport paths with non-zero contribution is dramatically increased, resulting in much less noisy images within a fixed time budget