5,229 research outputs found
Scan to BIM for 3D reconstruction of the papal basilica of saint Francis in Assisi In Italy
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
Optimization of an axial fan for air cooled condensers
We report on the low noise optimization of an axial fan specifically designed for the cooling of CSP power plants. The duty point presents an uncommon combination of a load coefficient of 0.11, a flow coefficient of 0.23 and a static efficiency ηstat > 0.6. Calculated fan Reynolds number is equal to Re = 2.85 x 107. Here we present a process used to optimize and numerically verify the fan performance. The optimization of the blade was carried out with a Python code through a brute-force-search algorithm. Using this approach the chord and pitch distributions of the original blade are varied under geometrical constraints, generating a population of over 24000 different possible individuals. Each individual was then tested using an axisymmetric Python code. The software is based on a blade element axisymmetric principle whereby the rotor blade is divided into a number of streamlines. For each of these streamlines, relationships for velocity and pressure are derived from conservation laws for mass, tangential momentum and energy of incompressible flows. The final geometry was eventually chosen among the individuals with the maximum efficiency. The final design performance was then validated through with a CFD simulation. The simulation was carried out using a RANS approach, with the cubic k - low Reynolds turbulence closure of Lien et al. The numerical simulation was able to verify the air performance of the fan and was used to derive blade-to-blade distributions of design parameters such as flow deviation, velocity components, specific work and diffusion factor of the optimized blade. All the computations were performed in OpenFoam, an open source C++- based CFD library. This work was carried out under MinWaterCSP project, funded by EU H2020 programme
Arrested state of clay-water suspensions: gel or glass?
The aging of a charged colloidal system has been studied by Small Angle
X-rays Scattering, in the exchanged momentum range Q=0.03 - 5 nm-1, and by
Dynamic Light Scattering, at different clay concentrations (Cw =0.6 % - 2.8 %).
The static structure factor, S(Q), has been determined as a function of both
aging time and concentration. This is the first direct experimental evidence of
the existence and evolution with aging time of two different arrested states in
a single system simply obtained only by changing its volume fraction: an
inhomogeneous state is reached at low concentrations, while a homogenous one is
found at high concentrations.Comment: 5 pages, 2 figure
Deterministic Annealing as a jet clustering algorithm in hadronic collisions
We show that a general purpose clusterization algorithm, Deterministic
Annealing, can be adapted to the problem of jet identification in particle
production by high energy collisions. In particular we consider the problem of
jet searching in events generated at hadronic colliders. Deterministic
Annealing is able to reproduce the results obtained by traditional jet
algorithms and to exhibit a higher degree of flexibility.Comment: 13 pages, 6 figure
Euclidean Greedy Drawings of Trees
Greedy embedding (or drawing) is a simple and efficient strategy to route
messages in wireless sensor networks. For each source-destination pair of nodes
s, t in a greedy embedding there is always a neighbor u of s that is closer to
t according to some distance metric. The existence of greedy embeddings in the
Euclidean plane R^2 is known for certain graph classes such as 3-connected
planar graphs. We completely characterize the trees that admit a greedy
embedding in R^2. This answers a question by Angelini et al. (Graph Drawing
2009) and is a further step in characterizing the graphs that admit Euclidean
greedy embeddings.Comment: Expanded version of a paper to appear in the 21st European Symposium
on Algorithms (ESA 2013). 24 pages, 20 figure
Information Flow in Networks and the Law of Diminishing Marginal Returns: Evidence from Modeling and Human Electroencephalographic Recordings
We analyze simple dynamical network models which describe the limited capacity of nodes to process the input information. For a proper range of their parameters, the information flow pattern in these models is characterized by exponential distribution of the incoming information and a fat-tailed distribution of the outgoing information, as a signature of the law of diminishing marginal returns. We apply this analysis to effective connectivity networks from human EEG signals, obtained by Granger Causality, which has recently been given an interpretation in the framework of information theory. From the distributions of the incoming versus the outgoing values of the information flow it is evident that the incoming information is exponentially distributed whilst the outgoing information shows a fat tail. This suggests that overall brain effective connectivity networks may also be considered in the light of the law of diminishing marginal returns. Interestingly, this pattern is reproduced locally but with a clear modulation: a topographic analysis has also been made considering the distribution of incoming and outgoing values at each electrode, suggesting a functional role for this phenomenon
Planar Embeddings with Small and Uniform Faces
Motivated by finding planar embeddings that lead to drawings with favorable
aesthetics, we study the problems MINMAXFACE and UNIFORMFACES of embedding a
given biconnected multi-graph such that the largest face is as small as
possible and such that all faces have the same size, respectively.
We prove a complexity dichotomy for MINMAXFACE and show that deciding whether
the maximum is at most is polynomial-time solvable for and
NP-complete for . Further, we give a 6-approximation for minimizing
the maximum face in a planar embedding. For UNIFORMFACES, we show that the
problem is NP-complete for odd and even . Moreover, we
characterize the biconnected planar multi-graphs admitting 3- and 4-uniform
embeddings (in a -uniform embedding all faces have size ) and give an
efficient algorithm for testing the existence of a 6-uniform embedding.Comment: 23 pages, 5 figures, extended version of 'Planar Embeddings with
Small and Uniform Faces' (The 25th International Symposium on Algorithms and
Computation, 2014
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