Sharif Digital Repository

Let G be a graph and let f be a positive integer-valued function on V(G). In this paper, we show that if for all S⊆V(G), ω(G∖S)<∑v∈S(f(v)−2)+2+ω(G[S]), then G has a spanning tree T containing an arbitrary given matching such that for each vertex v, dT(v)≤f(v), where ω(G∖S) denotes the number of components of G∖S and ω(G[S]) denotes the number of components of the induced subgraph G[S] with the vertex set S. This is an improvement of several results. Next, we prove that if for all S⊆V(G), ω(G∖S)≤∑v∈S(f(v)−1)+1, then G admits a spanning closed walk passing through the edges of an arbitrary given matching meeting each vertex v at most f(v) times. This result solves a long-standing conjecture... 

This paper compares the results of a nonlinear finite element analysis (FEA) of an internal hybrid steel beam to RC column connections with those of the experiment on a half-scale. This study used extended face bearing plates (EFBP) embedded in the panel zone (PZ) to make prefabricated RC column to steel beam connections (PRCS). Steel beam flanges were made to be stronger than scaled sections to transfer more force to the PZ. Nonlinear FEA was performed with ABAQUS software to evaluate the connections under unidirectional loading. Failure mode, connection stiffness, and PZ shear strength determined by nonlinear FEA matched well with the experimental findings. PRCS1 model was used to evaluate... 

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... 

Steel-plate composite (SC) walls can be connected to a concrete basemat using a base plate and a set of anchors eccentric to the wall. The base plate can be separated into two parts so that the concrete of the wall and basemat is cohesive, and thus, the wall can be manufactured more easily and economically. Additionally, compression and shear demand are directly transferred from infill concrete to concrete basemat. Another change in the base plate connection of available tested walls involves transferring anchors to the bottom of faceplates. As a result of this modification, the base plate is removed from the force transmission chain, and the force is transferred directly from the wall to... 

In this paper, we show that every (3k−3)-edge-connected graph G, under a certain degree condition, can be edge-decomposed into k factors G1,…,Gk such that for each vertex v∈V(Gi), |dGi(v)−dG(v)/k|<1, where 1≤i≤k. As an application, we deduce that every 6-edge-connected graph G can be edge-decomposed into three factors G1, G2, and G3 such that for each vertex v∈V(Gi) with 1≤i≤3, |dGi(v)−dG(v)/3|<1, unless G has exactly one vertex z with dG(z)⁄≡30. Next, we show that every odd-(3k−2)-edge-connected graph G can be edge-decomposed into k factors G1,…,Gk such that for each vertex v∈V(Gi), dGi(v) and dG(v) have the same parity and |dGi(v)−dG(v)/k|<2, where k is an odd positive integer and 1≤i≤k.... 

Connected and Autonomous Vehicles (CAVs) are introduced to improve individuals' quality of life by offering a wide range of services. They collect a huge amount of data and exchange them with each other and the infrastructure. The collected data usually includes sensitive information about the users and the surrounding environment. Therefore, data security and privacy are among the main challenges in this industry. Blockchain, an emerging distributed ledger, has been considered by the research community as a potential solution for enhancing data security, integrity, and transparency in Intelligent Transportation Systems (ITS). However, despite the emphasis of governments on the transparency... 

In this research, the cyclic performance of double corrugated steel plate shear walls (DCSPSWs) is investigated experimentally and confirmed numerically. Three half-scale one-story single-bay specimens with different infill plate designs were constructed and tested under lateral cyclic loads. The design parameters examined were the connection between the corrugated plates and the connection between the infill plate and the columns. The results showed that regardless of the infill plate design, the DCSPSWs had a spindle-shaped hysteresis curve with good cyclic performance. However, the beam-only-connected DCSPSW exhibited slightly lower lateral load resistance. Finite element (FE) models of... 

The energy of a graph G, E(G), is defined as the sum of absolute values of the eigenvalues of its adjacency matrix. In Akbari and Hosseinzadeh (2020) [3] it was conjectured that for every graph G with maximum degree Δ(G) and minimum degree δ(G) whose adjacency matrix is non-singular, E(G)≥Δ(G)+δ(G) and the equality holds if and only if G is a complete graph. Let G be a connected graph with the edge set E(G). In this paper, first we show that E(L(G))≥|E(G)|+Δ(G)−5, where L(G) denotes the line graph of G. Next, using this result, we prove the validity of the conjecture for the line of each connected graph of order at least 7. © 2021 Elsevier Inc  

Flow through porous media depends strongly on the spatial distribution of the geological heterogeneities which appear on all length scales. We lack precise information about heterogeneity distribution on various scales, from pore level to reservoir scale. However, some sources provide suitable information. At pore scale, for example, the micro-CT images show considerable insights into pore space structures and play valuable role in porous media characterization. The consequence of all geological heterogeneities is a great deal of uncertainty in dynamic performance of porous media which can be investigated using percolation theory. The main percolation quantities include the connected pore... 

Saddle connections are semi-rigid connections that are widely used in Iran. Many existing buildings contain this type of connection. The present study conducted full-scale experiments and used extensive numerical modeling to study the mechanical characteristics of saddle connections. The mechanical characteristics examined were the moment-transfer mechanism, initial stiffness, yield moment, maximum moment, and fracture rotation. The configuration and dimensions of the experimental and numerical specimens were chosen to be similar to those of saddle connections in existing buildings. A parametric study was conducted to determine the factors affecting the mechanical characteristics of these... 

Asthma is a chronic inflammatory disease associated with a high prevalence of psychiatric disorders. There are specific brain networks responsible for emotional processes, including two important networks associated with psychiatric problems: the default mode network (DMN), which is more active in the resting state, and the salience network (SN), which is structurally connected to DMN. Although previous studies suggested that neuro-phenotypes of asthma may be recognizable by the neural activity of brain circuits, an association between the brain's functional alterations and psychiatric impairments induced by asthma remains unknown. We aimed to assess DMN and SN activity and its association... 

Given a weighted graph G=(V,E) with weight functions c:E→R+ and π:V→R+, and a subset U⊆V, the normalized cut value for U is defined as the sum of the weights of edges exiting U divided by the weight of vertices in U. The mean isoperimetry problem, ISO1(G,k), for a weighted graph G is a generalization of the classical uniform sparsest cut problem in which, given a parameter k, the objective is to find k disjoint nonempty subsets of V minimizing the average normalized cut value of the parts. The robust version of the problem seeks an optimizer where the number of vertices that fall out of the subpartition is bounded by some given integer 0≤ρ≤|V|. The problem may also be considered as the... 

In recent years, the regression dynamic causal modelling (rDCM) method was introduced as a new version of dynamic causal modelling (DCM) to derive effective connectivity in whole-brain networks for functional magnetic resonance imaging (fMRI) data. In this research, we used data obtained while applying the stimulation of audio movie comprised different emotional states. We applied this method to two networks consisting of ten auditory and forty-four regions, respectively. This method was used to study effective connections between emotional states and represent the distinction between emotions. Finally, significant effective connections were found in emotional processing and auditory... 

Pollutant emission is one of the most important problems the world faces. Using sustainable energies is among the best solutions which can be employed to reduce CO2 and other pollutants as in Environmental Protection Agency (EPA) standards. In this study, a case study region located in the south of Iran, including 100 households, is studied to find practical methods of investment to partially replace the required energy by renewables where the total emission is confined to the EPA standards. The solar irradiant of the region is 5.36 kWh/m2/day which causes high energy consumption (3000 kWh/day). If the government invests $495705, which is equal to the social penalty that has to be paid for... 

Purpose: The paper aims to report a fire test conducted on a three-dimensional frame in order to investigate the behaviour of bare steel flush end-plate connections with relatively low thickness at elevated temperatures. Design/methodology/approach: A half-scale model was fabricated and exposed to modified (scaled) ISO 834 heating curve using a semi-open furnace. The maximum temperature inside the furnace reached 1,026 °C. Findings: The rotations of connections are reported and compared with those of a previous study on an exactly the same model with thick end-plates. Various modes of failure such as local buckling of the beams flanges and lateral-torsional buckling of beams were observed... 

The visibility graph of a polygon corresponds to its internal diagonals and boundary edges. For each vertex on the boundary of the polygon, we have a vertex in this graph and if two vertices of the polygon see each other there is an edge between their corresponding vertices in the graph. Two vertices of a polygon see each other if and only if their connecting line segment completely lies inside the polygon. Recognizing visibility graphs is the problem of deciding whether there is a simple polygon whose visibility graph is isomorphic to a given graph. Another important problem is to reconstruct such a polygon if there is any. These problems are well known and well-studied, but yet open... 

Many studies in the field of sleep have focused on connectivity and coherence. Still, the nonstationary nature of electroencephalography (EEG) makes many of the previous methods unsuitable for automatic sleep detection. Time-frequency representations and high-order spectra are applied to nonstationary signal analysis and nonlinearity investigation, respectively. Therefore, combining wavelet and bispectrum, wavelet-based bi-phase (Wbiph) was proposed and used as a novel feature for sleep-wake classification. The results of the statistical analysis with emphasis on the importance of the gamma rhythm in sleep detection show that the Wbiph is more potent than coherence in the wake-sleep... 

Purpose: Alzheimer's disease (AD) starts years before its signs and symptoms including the dementia become apparent. Diagnosis of the AD in the early stages is important to reduce the speed of brain decline. Aim of the study: Identifying the alterations in the functional connectivity of the brain during the disease stages is among the main important issues in this regard. Therefore, in this study, the changes in the functional connectivity during the AD stages were analyzed. Materials and methods: By employing the functional magnetic resonance imaging (fMRI) data and graph theory, weighted undirected graphs of the whole-brain and default mode network (DMN) network were investigated... 

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 &... 

Supercoiled DNA, crumpled interphase chromosomes, and topologically constrained ring polymers often adopt treelike, double-folded, randomly branching configurations. Here we study an elastic lattice model for tightly double-folded ring polymers, which allows for the spontaneous creation and deletion of side branches coupled to a diffusive mass transport, which is local both in space and on the connectivity graph of the tree. We use Monte Carlo simulations to study systems falling into three different universality classes: ideal double-folded rings without excluded volume interactions, self-avoiding double-folded rings, and double-folded rings in the melt state. The observed static properties...