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    On the analytical model of beam-to-column semi-rigid connections, using plate theory

    , Article Thin-Walled Structures ; Volume 39, Issue 4 , 2001 , Pages 307-325 ; 02638231 (ISSN) Mofid, M ; Ghorbani Asl, M ; McCabe, S. L ; Sharif University of Technology
    2001
    Abstract
    An analytical method is presented that can be used to determine the behavior of a particular steel beam-to-column extended end plate connection, in both linear and non-linear regions. This article demonstrates a closed form solution of the equations of deformation, for this type of connection. Besides, a step-by-step analytical procedure for establishment of the linear part of M-θ curve of this form of connection is developed. However, this technique can properly be extended to the non-linear regions, which is not considered in this article. The correctness of the results has been ascertained by a comparison, using non-linear finite element models as well as experimental approach; and very... 

    Highly edge-connected factors using given lists on degrees

    , Article Journal of Graph Theory ; Volume 90, Issue 2 , 2019 , Pages 150-159 ; 03649024 (ISSN) Akbari, S ; Hasanvand, M ; Ozeki, K ; Sharif University of Technology
    Wiley-Liss Inc  2019
    Abstract
    Let G be a 2k-edge-connected graph with 𝑘 ≥ 0 and let 𝐿(𝑣) ⊆ {𝑘,…, 𝑑𝐺(𝑣)} for every 𝑣 ∈ 𝑉 (𝐺). A spanning subgraph F of G is called an L-factor, if 𝑑𝐹 (𝑣) ∈ 𝐿(𝑣) for every 𝑣 ∈ 𝑉 (𝐺). In this article, we show that if (Formula presented.) for every 𝑣 ∈ 𝑉 (𝐺), then G has a k-edge-connected L-factor. We also show that if 𝑘 ≥ 1 and (Formula presented.) for every 𝑣 ∈ 𝑉 (𝐺), then G has a k-edge-connected L-factor. © 2018 Wiley Periodicals, Inc  

    Equimatchable claw-free graphs

    , Article Discrete Mathematics ; Volume 341, Issue 10 , 2018 , Pages 2859-2871 ; 0012365X (ISSN) Akbari, S ; Alizadeh, H ; Ekim, T ; Gözüpek, D ; Shalom, M ; Sharif University of Technology
    Elsevier B.V  2018
    Abstract
    A graph is equimatchable if all of its maximal matchings have the same size. A graph is claw-free if it does not have a claw as an induced subgraph. In this paper, we provide the first characterization of claw-free equimatchable graphs by identifying the equimatchable claw-free graph families. This characterization implies an efficient recognition algorithm. © 2018 Elsevier B.V  

    A note on the bounded fragmentation property and its applications in network reliability

    , Article European Journal of Combinatorics ; Volume 24, Issue 7 , 2003 , Pages 891-896 ; 01956698 (ISSN) Hajiaghayi, M. T ; Hajiaghayi, M ; Sharif University of Technology
    2003
    Abstract
    In this paper, we introduce a new property for graphs called bounded fragmentation, by which we mean after removing any set of at most k vertices the number of connected components is bounded only by a function of k. We demonstrate how bounded fragmentation can be used to measure the reliability of a network and introduce several classes of bounded fragmentation graphs. Finally, we pose some open problems related to this concept. © 2003 Elsevier Ltd. All rights reserved  

    Assessment of the semi-rigid double-angle steel connections and parametric analyses on their initial stiness using FEM

    , Article Scientia Iranica ; Volume 22, Issue 6 , 2015 , Pages 2033-2045 ; 10263098 (ISSN) Esfahanian, A ; Mohamadi Shooreh, M. R ; Mod, M ; Sharif University of Technology
    Abstract
    In this paper, the semi-rigid connections, such as Double-angle Web (DW) connections, which are welded to the beam web and bolted to the column ange, are investigated. This study tries to establish the eect of clearance setback between beam end and column ange and/or web. When the beam rotates, it is desirable to avoid bottom ange of the beam bearing against the column as this can induce large forces on the connection. The usual way of achieving this is to ensure that the connection extends at least a few millimeters beyond the end of beam. For this purpose, several connections are designed and considered based on two dierent shear capacities for the beam. For each connection, two dierent... 

    On the isoperimetric spectrum of graphs and its approximations [electronic resource]

    , Article Journal of Combinatorial Theory, Series B ; Volume 100, Issue 4, July 2010, Pages 390–412 Daneshgar, A. (Amir) ; Hajiabolhassan, Hossein ; Javadi, Ramin ; Sharif University of Technology
    Abstract
    In this paper1 we consider higher isoperimetric numbers of a (finite directed) graph. In this regard we focus on the nth mean isoperimetric constant of a directed graph as the minimum of the mean outgoing normalized flows from a given set of n disjoint subsets of the vertex set of the graph. We show that the second mean isoperimetric constant in this general setting, coincides with (the mean version of) the classical Cheeger constant of the graph, while for the rest of the spectrum we show that there is a fundamental difference between the nth isoperimetric constant and the number obtained by taking the minimum over all n-partitions. In this direction, we show that our definition is the... 

    VDM: A model for vector dark matter

    , Article Journal of Cosmology and Astroparticle Physics ; Volume 2012, Issue 10 , 2012 ; 14757516 (ISSN) Farzan, Y ; Rezaeiakbarieh, A ; Sharif University of Technology
    IOP  2012
    Abstract
    We construct a model based on a new U(1) X gauge symmetry and a discrete Z 2 symmetry under which the new gauge boson is odd. The model contains new complex scalars which carry U(1) X charge but are singlets of the Standard Model. The U(1) X symmetry is spontaneously broken but the Z 2 symmetry is maintained, making the new gauge boson a dark matter candidate. In the minimal version there is only one complex scalar field but by extending the number of scalars to two, the model will enjoy rich phenomenology which comes in various phases. In one phase, CP is spontaneously broken. In the other phase, an accidental Z 2 symmetry appears which makes one of the scalars stable and therefore a dark... 

    Spanning trees and spanning Eulerian subgraphs with small degrees

    , Article Discrete Mathematics ; Volume 338, Issue 8 , August , 2015 , Pages 1317-1321 ; 0012365X (ISSN) Hasanvand, M ; Sharif University of Technology
    Elsevier  2015
    Abstract
    Liu and Xu (1998) and Ellingham, Nam and Voss (2002) independently showed that every k-edge-connected simple graph G has a spanning tree T such that for each vertex v, dT(v) ≤ ⌈ d(v)/k ⌉ + 2. In this paper we show that every k-edge-connected graph G has a spanning tree T such that for each vertex v, dT(v)≤ ⌈ d(v)-2/k ⌉ + 2; also if G has k edge-disjoint spanning trees, then T can be found such that for each vertex v, dT(v) ≤ ⌈ d(v)-1/k ⌉ + 1. This result implies that every (r-1)-edge-connected r-regular graph (with r ≥ 4) has a spanning Eulerian subgraph whose degrees lie in the set {2,4,6}; also reduces the edge-connectivity needed for some theorems due to Barát and Gerbner (2014) and... 

    On the isoperimetric spectrum of graphs and its approximations

    , Article Journal of Combinatorial Theory. Series B ; Volume 100, Issue 4 , July , 2010 , Pages 390-412 ; 00958956 (ISSN) Daneshgar, A ; Hajiabolhassan, H ; Javadi, R ; Sharif University of Technology
    2010
    Abstract
    In this paper. 11This article is a revised version of Daneshgar and Hajiabolhassan (2008) [19] distributed on arXiv.org (1'st, Jan. 2008). we consider higher isoperimetric numbers of a (finite directed) graph. In this regard we focus on the nth mean isoperimetric constant of a directed graph as the minimum of the mean outgoing normalized flows from a given set of n disjoint subsets of the vertex set of the graph. We show that the second mean isoperimetric constant in this general setting, coincides with (the mean version of) the classical Cheeger constant of the graph, while for the rest of the spectrum we show that there is a fundamental difference between the nth isoperimetric constant and... 

    On edge-path eigenvalues of graphs

    , Article Linear and Multilinear Algebra ; 2020 Akbari, S ; Azizi, S ; Ghorbani, M ; Li, X ; Sharif University of Technology
    Taylor and Francis Ltd  2020
    Abstract
    Let G be a graph with vertex set (Formula presented.) and (Formula presented.) be an (Formula presented.) matrix whose (Formula presented.) -entry is the maximum number of internally edge-disjoint paths between (Formula presented.) and (Formula presented.), if (Formula presented.), and zero otherwise. Also, define (Formula presented.), where D is a diagonal matrix whose i-th diagonal element is the number of edge-disjoint cycles containing (Formula presented.), whose (Formula presented.) is a multiple of J−I. Among other results, we determine the spectrum and the energy of the matrix (Formula presented.) for an arbitrary bicyclic graph G. © 2020 Informa UK Limited, trading as Taylor &... 

    On connected colourings of graphs

    , Article Ars Combinatoria ; Volume 89 , 2008 , Pages 115-126 ; 03817032 (ISSN) Daneshgar, A ; Hajiabolhassan, H ; Hamedazimi, N ; Sharif University of Technology
    2008
    Abstract
    In this paper, first we introduce the concept of a connected graph homomorphism as a homomorphism for which the inverse image of any edge is either empty or a connected graph, and then we concentrate on chromatically connected (resp. chromatically disconnected) graphs such as G for which any χ(G)-colouring is a connected (resp. disconnected) homomorphism to K χ(G). In this regard, we consider the relationships of the new concept to some other notions as uniquely-colourability. Also, we specify some classes of chromatically disconnected graphs such as Kneser graphs KG(m, n) for which m is sufficiently larger than n, and the line graphs of non-complete class II graphs. Moreover, we prove that... 

    On edge-path eigenvalues of graphs

    , Article Linear and Multilinear Algebra ; Volume 70, Issue 15 , 2022 , Pages 2998-3008 ; 03081087 (ISSN) Akbari, S ; Azizi, S ; Ghorbani, M ; Li, X ; Sharif University of Technology
    Taylor and Francis Ltd  2022
    Abstract
    Let G be a graph with vertex set (Formula presented.) and (Formula presented.) be an (Formula presented.) matrix whose (Formula presented.) -entry is the maximum number of internally edge-disjoint paths between (Formula presented.) and (Formula presented.), if (Formula presented.), and zero otherwise. Also, define (Formula presented.), where D is a diagonal matrix whose i-th diagonal element is the number of edge-disjoint cycles containing (Formula presented.), whose (Formula presented.) is a multiple of J−I. Among other results, we determine the spectrum and the energy of the matrix (Formula presented.) for an arbitrary bicyclic graph G. © 2020 Informa UK Limited, trading as Taylor &... 

    One-hop throughput of wireless networks with random connections

    , Article IEEE Wireless Communications Letters ; Volume 1, Issue 3 , 2012 , Pages 205-208 ; 21622337 (ISSN) Shariatpanahi, S. P ; Khalaj, B. H ; Alishahi, K ; Shah Mansouri, H ; Sharif University of Technology
    2012
    Abstract
    We consider one-hop communication in wireless networks with random connections. In the random connection model, the channel powers between different nodes are drawn from a common distribution in an i.i.d. manner. In a wireless network with n nodes, a simple one-hop scheme achieving the throughput scaling of order n 1/3-δ, for any arbitrarily small δ > 0, is proposed. This scheme is based on maximizing the number of successful concurrent transmissions. Such achievable throughput, along with the order n 1/3 upper bound derived by Cui et al., characterizes the throughput of one-hop schemes for the class of connection models with distribution having finite mean and variance  

    Study on optimized piled-raft foundations (PRF) performance with connected and non-connected piles- three case histories

    , Article International Journal of Civil Engineering ; Volume 10, Issue 2 , 2012 , Pages 100-111 ; 17350522 (ISSN) Eslami, A ; Veiskarami, M ; Eslami, M. M ; Sharif University of Technology
    2012
    Abstract
    It has been realized that the raft (mat) foundations are capable of bearing very large loads when they are assisted with a pile group. The contribution of both raft and piles to carry the surcharge loads is taken into account, considering the stiffness and strength of involved elements in the system, i.e. piles, raft and surrounding soil. The piles are usually required not to ensure the overall stability of the foundation but to act as settlement reducers. There is an alternative design in which, the piles are nonconnected from the raft to reduce the settlement, which are then known to be "settlement reducer non-connected piles" to increase the system stiffness. In this paper, two and three... 

    Total domination and total domination subdivision numbers

    , Article Australasian Journal of Combinatorics ; Volume 38 , 2007 , Pages 229-235 ; 10344942 (ISSN) Favaron, O ; Karami, H ; Sheikholeslami, S. M ; Sharif University of Technology
    2007
    Abstract
    A set S of vertices of a graph G = (V, E) without isolated vertex is a total dominating set if every vertex of V(G) is adjacent to some vertex in S.The total domination number γ<(G) is the minimum cardinality of a total dominating set of G. The total domination subdivision number sdγt(G) is the minimum number of edges that must be subdivided (each edge in G can be subdivided at most once) in order to increase the total domination number. We show that sdγt(G) ≤ n - γt(G) + 1 for any graph G of order n ≥ 3 and that sdγt(G) < n-γt(G) except if G ≃ P3, C3, K4, P6 or C6  

    Innovative structural joint tolerates high rotational and shear overload

    , Article 23rd International Conference on Offshore Mechanics and Arctic Engineering, Vancouver, BC, 20 June 2004 through 25 June 2004 ; Volume 1 B , 2004 , Pages 875-883 Khonsari, S. V ; Parvinnia, S. M. H ; England, G. L ; Hajialiakbari Fini, E ; Sharif University of Technology
    2004
    Abstract
    A new beam-to-column and bracing-to-frame connection that can tolerate high rotational and shear overload is described. The connection is a self-contained separate entity that comprises two parallel attachment plates between which two circular tubes are laid and fixed through welding. The whole combination can also be produced by extrusion, where the plates are laid in an orthogonal relation with the axis of bending. In the welded version, the two plates are laid in a parallel relation with the axis of bending  

    Further investigation into a novel concept for a deformable joint in offshore structures

    , Article 22nd International Conference on Offshore Mechanics and Arctic Engineering; Offshore Technology Ocean Space Utilization, Cancun, 8 June 2003 through 13 June 2003 ; Volume 1 , 2003 , Pages 479-487 Khonsari, S. V ; England, G. L ; Parvinnia, S. M. H ; Sharif University of Technology
    2003
    Abstract
    A new general semi-rigid beam-to-column connection for skeletal structures, also applicable to offshore platforms, was devised. In a previous paper (OMAE02-28264), the general features of this joint together with some proposed details for its use in fabricating new platforms, as well as retrofitting and repair of existing platforms, were introduced. Moreover, the results of some quasi-static tests on the 'original' version of the connection, in which the energy-dissipating elements (tubes) of the connection are laid in a parallel relation to the axis of bending, were reported. Here, in this paper, the results of recent experimental work on the 'alternate' version of the connection, in which... 

    On the analytical model of semi-hinged steel connections, using plate theory

    , Article Thin-Walled Structures ; Volume 40, Issue 6 , 2002 , Pages 487-501 ; 02638231 (ISSN) Mofid, M ; Azizpour, S ; McCabe, S. L ; Sharif University of Technology
    2002
    Abstract
    An analytical method is presented that can be used to determine the behavior of a particular steel beam-to-column top and seat angle connection with double web angles. This article demonstrates a closed form solution of the equations of deformation, for this type of connection. Besides, a step-by-step analytical procedure for establishment of the linear part of M-θ curve of this form of connection is developed. However, this technique can properly be extended to the non-linear regions, which is not considered in this article. The correctness of the results has been ascertained by a comparison, using experimental approach as well as different analytical technique; and very good agreement has... 

    Brain Connectivity Analysis from EEG Signals using Entropy based Measures

    , M.Sc. Thesis Sharif University of Technology Saboksayr, Saman (Author) ; Shamsollahi, Mohammad Bagher (Supervisor)
    Abstract
    Even in the simplest of activities in the brain such as resting condition, there are connections in between different regions of the brain so that the whole system functions consistently in harmony. Studies related to brain connectivity provides an opportunity to better understand how the brain works. To assess these connectivities an estimation is usually conducted based on brain signals. Among different estimation methods, quantities of information theory are in general more practical due to avoiding any assumptions toward the system model and the ability to recognize linear and non-linear connectivity. One of the main quantities related to the information theory is in fact, entropy.... 

    Analyzing and Modeling of Novel Semi- fixed Beam to Column Connections in Steel Structures

    , M.Sc. Thesis Sharif University of Technology Boroumandi, Babak (Author) ; Mofid, Massoud (Supervisor)
    Abstract
    The flexibility of beam to column connections and its effect on behavior of steel structures is one of the most important problems, which is interesting to engineers and scientists for more than 80 years. Hence many studies conducted on this topic to clarify the behavior of this type of connection. In this work, it is tried to study the behavior of double plate connections, which are welded to the beam web by finite element modeling and mathematical method. A novelty of this thesis is some top trough plate which has been implemented to column under beam flange. Based on finding of this thesis few recommendation can be made related to usage of top trough plate. In brief reduction of...