8,991 research outputs found

    Afterword. «XY» thirty years later / Postfazione. «XY» trent’anni dopo

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    The «XY» magazine has a history, and this history is linked to Roberto de Rubertis who was the creator and “driving force” since he began his publication, in 1986 for CEDIS, with the title «XY dimensioni del disegno», a critical review of studies on the representation of architecture and the use of the image in science, technology and art. The magazine declared programmatically the will to stimulate and disseminate the theoretical and applied research produced in scientific areas of drawing and design, collecting important contributions also from conferences and seminars such as “The scientific foundations of representation”, developing over the years monographic and interdisciplinary topics including 1968–1988 Twenty years of drawn architecture, Survey dossier, Graphics–Architecture, Survey between history and science, and finally The places of epochal signs about the “suburbs” observed from a linguistic and figurative perspective

    Drawings, maps and maquettes. Plan-relief landscape depiction

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    Over the XVIII Century, different representation techniques combined on a map, i.e at the same time orthogonal projections and perspective view, try to simulate a tridimensional image definitely useful for better understanding and recognizing a place. These representation techniques, even when employed in that time to make war or to state nation boundaries, depict landscape exploiting visual parameters, fixing on maps and drawings very bright colors, shades and tones of objects, coupled with their exact position on the land. Within this framework, the Plan-Relief, which literally means “Relief Map”, is a physical model of a place and can be considered as a case for a very detailed description of landscape and territory in order to get the utmost clarity. Taking in consideration the background, the paper aims mostly to show and illustrate the techniques of landscape drawing and survey, how they had been applied in the several steps required for the design and realization of Plans-Reliefs, particularly focusing on the procedures for providing maps and elevation needed for building the physical model. The analysis about techniques of representation employed in realizing Plans-Reliefs can further allow a comparison with landscape representation nowadays: in fact, after a long time it has been mostly grounded in metrical and geometrical parameters, landscape representation seems to turn again to a perceptual and pictorial criterion


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    In the framework of an integrated modeling approach at regional and local scale, some models have been implemented and run in our institution: the SISL-MSM by us, the MESO-NH by the Laboratoire de Aerologie and Meteo-France, the ETA Model by NCEP, the MC2 model by CMC-Environment Canada and the WRF model (by many agencies). Boundary conditions are provided by our ESM (European Spectral Model) which is nested in our GSS (Global Simulation System), a global model and an ensemble prediction system. A case study of a summer thunderstorm in the south-alpine region is presented, with simulation made by different models and grid mesh sizes in the same area. Observational data have been compared to the model simulations. The comparison shows the differences among the models and simulation designs in the complex topography of the Alps, the characteristics of the atmosphere behaviour in mountain regions and the importance of non-hydrostatic effects to correctly reproduce the overall physics and dynamics at the mesoscale

    Corso di formazione in "Medicina, Individuo, SocietĂ ". Atti 2009

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    Il volume raccoglie gli atti del corso di formazione celebrato in Accademia delle Scienze Mediche di Palermo, dove sono state trattate tematiche di "Etica e Management in SanitĂ "

    Lagrangian Formalism in Perturbed Nonlinear Klein-Gordon Equations

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    We develop an alternative approach to study the effect of the generic perturbation (in addition to explicitly considering the loss term) in the nonlinear Klein-Gordon equations. By a change of the variables that cancel the dissipation term we are able to write the Lagrangian density and then, calculate the Lagrangian as a function of collective variables. We use the Lagrangian formalism together with the Rice {\it Ansatz} to derive the equations of motion of the collective coordinates (CCs) for the perturbed sine-Gordon (sG) and ϕ4\phi^{4} systems. For the NN collective coordinates, regardless of the {\it Ansatz} used, we show that, for the nonlinear Klein-Gordon equations, this approach is equivalent to the {\it Generalized Traveling Wave Ansatz} ({\it GTWA})Comment: 9 page

    Discrete Nonlinear Schrodinger Equations with arbitrarily high order nonlinearities

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    A class of discrete nonlinear Schrodinger equations with arbitrarily high order nonlinearities is introduced. These equations are derived from the same Hamiltonian using different Poisson brackets and include as particular cases the saturable discrete nonlinear Schrodinger equation and the Ablowitz-Ladik equation. As a common property, these equations possess three kinds of exact analytical stationary solutions for which the Peierls-Nabarro barrier is zero. Several properties of these solutions, including stability, discrete breathers and moving solutions, are investigated

    Analytical approach to soliton ratchets in asymmetric potentials

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    We use soliton perturbation theory and collective coordinate ansatz to investigate the mechanism of soliton ratchets in a driven and damped asymmetric double sine-Gordon equation. We show that, at the second order of the perturbation scheme, the soliton internal vibrations can couple {\it effectively}, in presence of damping, to the motion of the center of mass, giving rise to transport. An analytical expression for the mean velocity of the soliton is derived. The results of our analysis confirm the internal mode mechanism of soliton ratchets proposed in [Phys. Rev. E {\bf 65} 025602(R) (2002)].Comment: 9 figures. Submitted to Phys. Rev.

    Local-Scale Weather Forecasts over a Complex Terrain in an Early Warning Framework: Performance Analysis for the Val d'Agri (Southern Italy) Case Study

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    Forecasting applications based on hourly meteorological predictions for weather variables are nowadays used in energy market operations, planning of gas and power supply, and renewable energy, among others. Available meteorological and climatological data, as well as critical thresholds of rainfall, may also have a key role in the hazard classification, related to slope instabilities of pipelines and critical infrastructures along routes. The present study concerns the performance of a weather forecast model in the framework of an early warning system (EWS) application, which supports the integrity management of oil and gas pipelines. This EWS has been applied on to a specific area: the Val d'Agri basin in the Basilicata region of Southern Italy, which is extensively affected by several landslides and floods. The hourly precipitation forecasts are provided by a dedicated meteorological model, the KALM-HD, using two different horizontal resolutions, 1.25 and 5 km, to analyze possible influences of the mesh grid size as well. On this area, several weather stations were specifically deployed to obtain observed data in a region where hydrogeological hazards are relevant for asset management. A comparison among observations and the KALM-HD scaled forecasts on six of these weather stations is presented to assess the model performance. Besides, precipitation, temperature, and wind speed are evaluated as well. The forecasting analysis is performed considering two years of data both on an overall and seasonal basis. Results show that the KALM-HD performs well with the 1.25 km grid, particularly on temperature and wind speed variables. Since weather stations can be gathered in two main sets depending on their positions, differences arise in the forecast quality of these two groups, related to orography and thermal effects, whose detection is difficult in the typical narrow valleys characterizing the area of study. This issue prevalently influences temperatures and local winds, which, these latter, are generally underestimated, while precipitation is mainly driven by synoptic circulation and its interaction with mesoscale meteorological features