Search results for " Index"
showing 10 items of 4978 documents
Green roofs for smart cities: experimental determination of the “fractional vegetation coverage” of six vegetated species
2015
Towards a de-carbonization of European countries, green roofs are becoming popular, due not only to aesthetic reasons but also to energy and environmental issues. Indeed, especially in summer periods, the building cooling demand might be sensibly cut thanks to such passive components often chosen for planning smart cities. To properly model the energy performances of buildings equipped with these components, a particular attention must be paid to radiative exchanges occurring among soil surface, leaves and outdoor surroundings. These thermal exchanges depend on parameters, like the “fractional vegetation coverage” whose literature data do not seem particularly suitable for the simulation ne…
Risk indexes evaluation in view of a new showcase designing of “L’Annunciata” by Antonello da Messina
2018
Museums are often hosted by heritage buildings, where the indoor thermal conditions are usually subjected to a free-floating regime, due to the difficulty of equipping them with HVAC systems that, generally, are highly impacting tools from a visual point of view. These technological tools, in fact, could conflict with the established arrangement of the works of art. This would represent a problem, since the indoor physical conditions of these premises must fall within the ranges of values suitable to ensure the safety of the works of art there exhibited. In addition, the increasing time spent by visitors inside museums (now offering various possibilities of leisure, ranging from the book sh…
Approccio integrato per la caratterizzazione delle murature storiche siciliane. Il caso di Gangi
2022
This study is part of a research aimed at developing a database of mechanical and hygrothermal information for Sicilian historic walls. This database is intended to support the analysis of the envelope performances of the historic building and to integrate data collected through in-situ measurements. The method is based on the analysis of local contexts: stone walls are divided in typologies according to the detailed non-destructive examination of the historic building stock, and laboratory and in-situ tests are carried out to characterize the mechanical and thermophysical properties of walls and masonry materials. This study focuses on the local context of Gangi, where a large amount of hi…
Load modelling influence on voltage stability assessment in distribution systems. Part II: Extension to a complex radial system and applications
2006
The single-line equivalent model is commonly used for voltage stability studies in both distribution and transmission systems. Referring to a single-line system, in the companion paper [1] the authors presented the theoretical aspects of voltage stability related to the load characteristics. In particular, expressions of the stability index for constant power, constant impedance and constant current loads, singularly and in all the possible combinations have been obtained. This index indicates how far the load node is from its voltage collapse point, allowing the maximum load power beyond which voltage collapse takes place to be evaluated. In this paper a simple method to evaluate the param…
Load modelling influence on voltage stability assessment in distribution systems. Part I: Stability index and critical power for a single-line system
2006
The single-line equivalent model is commonly used for voltage stability studies in both distribution and transmission systems. Referring to a single-line system, in the companion paper [1] the authors presented the theoretical aspects of voltage stability related to the load characteristics. In particular, expressions of the stability index for constant power, constant impedance and constant current loads, singularly and in all the possible combinations have been obtained. This index indicates how far the load node is from its voltage collapse point, allowing the maximum load power beyond which voltage collapse takes place to be evaluated. In this paper a simple method to evaluate the param…
An improved method for determining voltage collapse proximity of radial distribution networks
2005
The two-bus equivalent model is commonly used for voltage stability studies in both distribution and transmission systems. The paper presents a simple method to evaluate, for each bus, the parameters which define the equivalent circuit of a radial distribution network. In particular, a straightforward way for determining the Thévenin equivalent impedance behind a load node is proposed, which allows to better identify the maximum loading point beyond which the voltage collapse takes place in the network. Simulation results show that the proposed method is significantly more accurate than other existing methods on evaluating the critical power at a particular node (i.e. the weak node of the n…
Assessing Coastal Sustainability: A Bayesian Approach for Modeling and Estimating a Global Index for Measuring Risk
2013
Integrated Coastal Zone Management is an emerg- ing research area. The aim is to provide a global view of dif- ferent and heterogeneous aspects interacting in a geographical area. Decision Support Systems, integrating Computational Intelligence methods, can be successfully used to estimate use- ful anthropic and environmental indexes. Bayesian Networks have been widely used in the environmental science domain. In this paper a Bayesian model for estimating the Sustainable Coastal Index is presented. The designed Bayesian Network consists of 17 nodes, hierarchically organized in 4 layers. The first layer is initialized with the season and the physiographic region information. In the second la…
A New Class of Searchable and Provably Highly Compressible String Transformations
2019
The Burrows-Wheeler Transform is a string transformation that plays a fundamental role for the design of self-indexing compressed data structures. Over the years, researchers have successfully extended this transformation outside the domains of strings. However, efforts to find non-trivial alternatives of the original, now 25 years old, Burrows-Wheeler string transformation have met limited success. In this paper we bring new lymph to this area by introducing a whole new family of transformations that have all the "myriad virtues" of the BWT: they can be computed and inverted in linear time, they produce provably highly compressible strings, and they support linear time pattern search direc…
Unifying Textual and Visual Cues for Content-Based Image Retrieval on the World Wide Web
1999
A system is proposed that combines textual and visual statistics in a single index vector for content-based search of a WWW image database. Textual statistics are captured in vector form using latent semantic indexing based on text in the containing HTML document. Visual statistics are captured in vector form using color and orientation histograms. By using an integrated approach, it becomes possible to take advantage of possible statistical couplings between the content of the document (latent semantic content) and the contents of images (visual statistics). The combined approach allows improved performance in conducting content-based search. Search performance experiments are reported for…
Video Indexing Using MPEG Motion Compensation Vectors
2003
In the last years a lot of work has been done on color, textural, structural and semantic indexing of "content-based" video databases. Motion-based video indexing has been less explored, with approaches generally based on the analysis of optical flows. Compressed videos require the decompression of the sequences and the computation of optical flows, two steps computationally heavy. In this paper we propose some methods to index videos by motion features (mainly related to camera motion) and by motion-based spatial segmentation of frames, in a fully automatic way. Our idea is to use MPEG motion vectors as an alternative to optical flows. Their extraction is very simple and fast; it doesn't r…