6,138 research outputs found
A novel approach to CFD analysis of the urban environment
The construction of cities, with their buildings and human activities, not only changes the landscape, but also influences the local climate in a manner that depends on many different factors and parameters: weather conditions, urban thermo-physical and geometrical characteristics, anthropogenic moisture and heat sources. Land-cover and canopy structure play an important role in urban climatology and every environmental assessment and city design face with them.
Inside the previous frame, the objective of this study is both to identify both the key design variables that alter the environment surrounding the buildings, and to quantified the extension area of these phenomena. The tool used for this study is a 2D computational fluid dynamics (CFD) numerical simulation considering different heights for buildings, temperature gaps between undisturbed air and buildingâs walls, velocities of undisturbed air. Results obtained allowed to find a novel approach to study urban canopies, giving a qualitative assessment on the contribution and definition of the total energy of the area surrounding the buildings
Earthquake scenarios and seismic input for cultural heritage: applications to the cities of Rome and Florence
For historical buildings and monuments, i.e. when considering time intervals
of about a million year (we do not want to loose cultural heritage), the
applicability of standard estimates of seismic hazard is really questionable. A
viable alternative is represented by the use of the scenario earthquakes,
characterized at least in terms of magnitude, distance and faulting style, and
by the treatment of complex source processes. Scenario-based seismic hazard
maps are purely based on geophysical and seismotectonic features of a region
and take into account the occurrence frequency of earthquakes only for their
classification into exceptional (catastrophic), rare (disastrous), sporadic
(very strong), occasional (strong) and frequent. Therefore they may provide an
upper bound for the ground motion levels to be expected for most regions of the
world, more appropriate than probabilities of exceedance in view of the long
time scales required for the protection of historical buildings. The
neo-deterministic approach naturally supplies realistic time series of ground
motion, which represent also reliable estimates of ground displacement readily
applicable to seismic isolation techniques, useful to preserve historical
monuments and relevant man made structures. This methodology has been
successfully applied to many urban areas worldwide for the purpose of seismic
microzoning, to strategic buildings, lifelines and cultural heritage sites; we
will discuss its application to the cities of Rome and Florence
The emergence of new technologies in the ICT field: main actors, geographical distribution and knowledge sources
This paper examines the emergence of technologies, applications and platforms in the area of information and communication technologies (ITC), using patent data. It detects new technologies/applications/products using patents' abstracts and describes them looking at their degree of "hybridisation", in terms of technological domains and knowledge base, at the role of firms in driving the innovation activity, and at the geographical distribution of the innovation. The results show that in emerging technologies in ITC are more concentrated across technological classes and across firms than non emerging ones, and that this pattern is invariant across major countries. Furthermore, a preliminary analysis on patent citations show that in emerging technologies knowledge sources are more specific in terms of technological classes and more dispersed in terms of cited institutions. Also there is evidence of a role for universities and public research centres as sources of knowledge
Innovation and Knowledge Spillovers: Evidence from European Data
This paper analyses the relative effects of national, international, sectoral and intersectoral spillovers on innovative activity in six large, industrialized countries (France, Germany, Italy, Japan, UK and US) over the period 1981-1995. This is done controlling for firm level effects and accounting for spillovers from universities and public institutions. We use patent applications at the European Patent Office to measure innovation and their citations to trace knowledge flows within and across 135 narrowly defined technological classes. We find that international spillovers are an important determinant of innovation and mostly occur within narrowly defined technological classes. Firm level effects are particularly noteworthy at the national level while we do not find evidence of spillovers from public institutions. Finally some important sectoral differences emerge.R&D spillovers, Knowledge flows, Patent citations.
De Gustibus Disputandum
We propose a simple method to predict individuals' expectations about
products using a knowledge network. As a complementary result, we show that the
method is able, under certain conditions, to extract hidden information at
neural level from a customers' choices database
A Pedagogical Intrinsic Approach to Relative Entropies as Potential Functions of Quantum Metrics: the - Family
The so-called -z-\textit{R\'enyi Relative Entropies} provide a huge
two-parameter family of relative entropies which includes almost all well-known
examples of quantum relative entropies for suitable values of the parameters.
In this paper we consider a log-regularized version of this family and use it
as a family of potential functions to generate covariant symmetric
tensors on the space of invertible quantum states in finite dimensions. The
geometric formalism developed here allows us to obtain the explicit expressions
of such tensor fields in terms of a basis of globally defined differential
forms on a suitable unfolding space without the need to introduce a specific
set of coordinates. To make the reader acquainted with the intrinsic formalism
introduced, we first perform the computation for the qubit case, and then, we
extend the computation of the metric-like tensors to a generic -level
system. By suitably varying the parameters and , we are able to recover
well-known examples of quantum metric tensors that, in our treatment, appear
written in terms of globally defined geometrical objects that do not depend on
the coordinates system used. In particular, we obtain a coordinate-free
expression for the von Neumann-Umegaki metric, for the Bures metric and for the
Wigner-Yanase metric in the arbitrary -level case.Comment: 50 pages, 1 figur
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