6,438 research outputs found

    Scan to BIM for 3D reconstruction of the papal basilica of saint Francis in Assisi In Italy

    Get PDF
    The historical building heritage, present in the most of Italian cities centres, is, as part of the construction sector, a working potential, but unfortunately it requires planning of more complex and problematic interventions. However, policies to support on the existing interventions, together with a growing sensitivity for the recovery of assets, determine the need to implement specific studies and to analyse the specific problems of each site. The purpose of this paper is to illustrate the methodology and the results obtained from integrated laser scanning activity in order to have precious architectural information useful not only from the cultural heritage point of view but also to construct more operative and powerful tools, such as BIM (Building Information Modelling) aimed to the management of this cultural heritage. The Papal Basilica and the Sacred Convent of Saint Francis in Assisi in Italy are, in fact, characterized by unique and complex peculiarities, which require a detailed knowledge of the sites themselves to ensure visitor’s security and safety. For such a project, we have to take in account all the people and personnel normally present in the site, visitors with disabilities and finally the needs for cultural heritage preservation and protection. This aim can be reached using integrated systems and new technologies, such as Internet of Everything (IoE), capable of connecting people, things (smart sensors, devices and actuators; mobile terminals; wearable devices; etc.), data/information/knowledge and processes to reach the desired goals. The IoE system must implement and support an Integrated Multidisciplinary Model for Security and Safety Management (IMMSSM) for the specific context, using a multidisciplinary approach

    X-ray view of four high-luminosity Swift/BAT AGN: Unveiling obscuration and reflection with Suzaku

    Get PDF
    The Swift/BAT nine-month survey observed 153 AGN, all with ultra-hard X-ray BAT fluxes in excess of 10^-11 erg cm^-2 s^-1 and an average redshift of 0.03. Among them, four of the most luminous BAT AGN (44.73 < Log L(BAT) < 45.31) were selected as targets of Suzaku follow-up observations: J2246.0+3941 (3C 452), J0407.4+0339 (3C 105), J0318.7+6828, and J0918.5+0425. The column density, scattered/reflected emission, the properties of the Fe K line, and a possible variability are fully analyzed. For the latter, the spectral properties from Chandra, XMM-Newton and Swift/XRT public observations were compared with the present Suzaku analysis. Of our sample, 3C 452 is the only certain Compton-thick AGN candidate because of i) the high absorption and strong Compton reflection; ii) the lack of variability; iii) the "buried" nature, i.e. the low scattering fraction (<0.5%) and the extremely low relative [OIII] luminosity. In contrast 3C 105 is not reflection-dominated, despite the comparable column density, X-ray luminosity and radio morphology, but shows a strong long-term variability in flux and scattering fraction, consistent with the soft emission being scattered from a distant region (e.g., the narrow emission line region). The sample presents high (>100) X-to-[OIII] luminosity ratios, confirming the [OIII] luminosity to be affected by residual extinction in presence of mild absorption, especially for "buried" AGN such as 3C 452. Three of our targets are powerful FRII radio galaxies, making them the most luminous and absorbed AGN of the BAT Seyfert survey despite the inversely proportional N_H - L_X relation.Comment: A&A paper in press, 17 page

    Computing NodeTrix Representations of Clustered Graphs

    Full text link
    NodeTrix representations are a popular way to visualize clustered graphs; they represent clusters as adjacency matrices and inter-cluster edges as curves connecting the matrix boundaries. We study the complexity of constructing NodeTrix representations focusing on planarity testing problems, and we show several NP-completeness results and some polynomial-time algorithms. Building on such algorithms we develop a JavaScript library for NodeTrix representations aimed at reducing the crossings between edges incident to the same matrix.Comment: Appears in the Proceedings of the 24th International Symposium on Graph Drawing and Network Visualization (GD 2016

    Hierarchical Partial Planarity

    Full text link
    In this paper we consider graphs whose edges are associated with a degree of {\em importance}, which may depend on the type of connections they represent or on how recently they appeared in the scene, in a streaming setting. The goal is to construct layouts of these graphs in which the readability of an edge is proportional to its importance, that is, more important edges have fewer crossings. We formalize this problem and study the case in which there exist three different degrees of importance. We give a polynomial-time testing algorithm when the graph induced by the two most important sets of edges is biconnected. We also discuss interesting relationships with other constrained-planarity problems.Comment: Conference version appeared in WG201

    QUALITATIVE AND QUANTITATIVE EVALUATION OF THE LUMINANCE OF LASER SCANNER RADIATION FOR THE CLASSIFICATION OF MATERIALS

    Get PDF
    The main aim of this experimentation is the evaluation of potentialities of terrestrial laser scanner technology to carry-out, beyond topographic and morphological detection, non-invasive materic analysis of the scanned objects, with the prospective to evaluate the conservation of historical landmarks and cultural heritage of which Italy is the world leading country. Coherent lasers in the visible light range may lead to optical diffraction phenomena thus allowing for structural investigation and chemical analysis of the scanned objects. Application of LST in the visible range (λ = 585 nm) to a set of solid samples commonly applied in the construction (building) industry, differing in the crystallinity of their respective lattice, led to the following conclusions: a linear correlation has been established between degree of crystallization of solids and returning luminance of lasers after diffraction onto the solids surface; Gauss distribution of luminance data from diffraction onto less crystalline (plastics, glass) materials has been much narrow than more crystalline ones (metals, alloys, plasters). Both findings confirm that laser diffraction methods may be applied for fast materic determinations after simple LST scanning of solid samples. Bragg modeling of data, extensively applied for Xray diffraction methods (XRD), may be truly co-opted to Laser Scanning

    Simultaneous Orthogonal Planarity

    Full text link
    We introduce and study the OrthoSEFEk\textit{OrthoSEFE}-k problem: Given kk planar graphs each with maximum degree 4 and the same vertex set, do they admit an OrthoSEFE, that is, is there an assignment of the vertices to grid points and of the edges to paths on the grid such that the same edges in distinct graphs are assigned the same path and such that the assignment induces a planar orthogonal drawing of each of the kk graphs? We show that the problem is NP-complete for k3k \geq 3 even if the shared graph is a Hamiltonian cycle and has sunflower intersection and for k2k \geq 2 even if the shared graph consists of a cycle and of isolated vertices. Whereas the problem is polynomial-time solvable for k=2k=2 when the union graph has maximum degree five and the shared graph is biconnected. Further, when the shared graph is biconnected and has sunflower intersection, we show that every positive instance has an OrthoSEFE with at most three bends per edge.Comment: Appears in the Proceedings of the 24th International Symposium on Graph Drawing and Network Visualization (GD 2016

    Ordered Level Planarity, Geodesic Planarity and Bi-Monotonicity

    Full text link
    We introduce and study the problem Ordered Level Planarity which asks for a planar drawing of a graph such that vertices are placed at prescribed positions in the plane and such that every edge is realized as a y-monotone curve. This can be interpreted as a variant of Level Planarity in which the vertices on each level appear in a prescribed total order. We establish a complexity dichotomy with respect to both the maximum degree and the level-width, that is, the maximum number of vertices that share a level. Our study of Ordered Level Planarity is motivated by connections to several other graph drawing problems. Geodesic Planarity asks for a planar drawing of a graph such that vertices are placed at prescribed positions in the plane and such that every edge is realized as a polygonal path composed of line segments with two adjacent directions from a given set SS of directions symmetric with respect to the origin. Our results on Ordered Level Planarity imply NPNP-hardness for any SS with S4|S|\ge 4 even if the given graph is a matching. Katz, Krug, Rutter and Wolff claimed that for matchings Manhattan Geodesic Planarity, the case where SS contains precisely the horizontal and vertical directions, can be solved in polynomial time [GD'09]. Our results imply that this is incorrect unless P=NPP=NP. Our reduction extends to settle the complexity of the Bi-Monotonicity problem, which was proposed by Fulek, Pelsmajer, Schaefer and \v{S}tefankovi\v{c}. Ordered Level Planarity turns out to be a special case of T-Level Planarity, Clustered Level Planarity and Constrained Level Planarity. Thus, our results strengthen previous hardness results. In particular, our reduction to Clustered Level Planarity generates instances with only two non-trivial clusters. This answers a question posed by Angelini, Da Lozzo, Di Battista, Frati and Roselli.Comment: Appears in the Proceedings of the 25th International Symposium on Graph Drawing and Network Visualization (GD 2017

    Monotone Grid Drawings of Planar Graphs

    Full text link
    A monotone drawing of a planar graph GG is a planar straight-line drawing of GG where a monotone path exists between every pair of vertices of GG in some direction. Recently monotone drawings of planar graphs have been proposed as a new standard for visualizing graphs. A monotone drawing of a planar graph is a monotone grid drawing if every vertex in the drawing is drawn on a grid point. In this paper we study monotone grid drawings of planar graphs in a variable embedding setting. We show that every connected planar graph of nn vertices has a monotone grid drawing on a grid of size O(n)×O(n2)O(n)\times O(n^2), and such a drawing can be found in O(n) time

    Time-based Microblog Distillation

    Get PDF
    This paper presents a simple approach for identifying relevant and reliable news from the Twitter stream, as soon as they emerge. The approach is based on a near-real time systems for sentiment analysis on Twitter, implemented by Fondazione Ugo Bordoni, and properly modified in order to detect the most representative tweets in a specified time slot. This work represents a first step towards the implementation of a prototype supporting journalists in discovering and finding news on Twitter
    corecore