Semantic-based authorization architecture for Grid

There are a few issues that still need to be covered regarding security in the Grid area. One of them is authorization where there exist good solutions to define, manage and enforce authorization policies in Grid scenarios. However, these solutions usually do not provide Grid administrators with semantic-aware components closer to the particular Grid domain and easing different administration tasks such as conflict detection or resolution. This paper defines a proposal based on Semantic Web to define, manage and enforce security policies in a Grid scenario. These policies are defined by means of semantic-aware rules which help the administrator to create higher-level definitions with more expressiveness. These rules also permit performing added-value tasks such as conflict detection and resolution, which can be of interest in medium and large scale scenarios where different administrators define the authorization rules that should be followed before accessing a resource in the Grid. The proposed solution has been also tested providing some reasonable response times in the authorization decision process.     

Modeling and control of an airbrake electro‐hydraulic smart actuator

In this paper, an accurate model of an airbrake electro‐hydraulic smart actuator is obtained by physical considerations, and then different control strategies (variable‐gain proportional control, PT₁ control with switching integrator, and second order sub‐optimal sliding mode control) are proposed and analyzed. This application is innovative in the avionic field, and is one of the first attempts to realize a fly‐by‐wire system for airbrakes, oriented to its immediate employment and installation on current aircraft. The project was carried on with the participation of the Italian Ministry of Defense, and was commissioned to MAG, a leading provider of integrated systems and aviation services for aerospace. Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

Experimental and numerical analysis of heat transfer and airflow on an interactive building facade

The envelope of a building is mainly responsible for its energy demand. Different kinds of double skin facades (DSFs) are nowadays used as a building envelope to reduce the energy demand and improve aesthetical view of buildings. Although DSF are already extensively used, their thermal performance is not well understood. This study presents a decoupling method capable to evaluate thermal performances and analyze fluid phenomena in a DSF. The solar radiation effects were evaluated with an analytical model and computational fluid dynamics (CFD) simulations were used to evaluate complex flow and thermal effect on a commercial DSF. With the decoupling approach to account for the effects of solar radiation and flow, the numerical results obtained by the CFD approach agree well with the experimental data collected on a full scale test room with a ventilated DSF. The method can be used to establish a database to develop a tool for DSF design.     

Tuning rules for a quick start up in Dynamic Matrix Control

This paper pretends to offer design rules for the parameters adjustment of the Dynamic Matrix Control (DMC) to allow an easier starting up. The effect on the time response of each algorithm parameter that can be tuned by the user is studied in an unconstrained system. To this aim, the position of the closed loop poles of the equivalent system is calculated. To simplify the study and to obtain more direct conclusions the number of poles will be limited using a First Order Plus Death Time simplification of the real plant. Design rules proposed in this study are tested in some simulated benchmarks and in a real plant.     

Physical examination of arteriovenous fistula: The influence of professional experience in the detection of complications

Vascular access is one of the leading causes of mobilization of financial resources in health systems for people with chronic kidney disease on hemodialysis. Physical examination of the arteriovenous fistula (AVF) has demonstrated its effectiveness in identifying complications. We decided to evaluate the influence of nurses' professional experience in the detection of complications of the AVF (venous stenosis and steal syndrome). The study took place in eight hemodialysis centers between May and September of 2011 in the north of Portugal. Sample was constituted by registered nurses. The nurses involved in the experiment were divided in two groups: those who had more than 5 years of experience and those who had less than 5 years of experience. Ninety‐two nurses participated in the study: 34 nurses had less than 5 years of professional experience and 58 had more than 5 years of professional experience. In the practices considered by nurses in the detection of venous stenosis, there were no differences observed between the groups (P > 0.05). In steal syndrome, there were no differences observed between the groups in the practices of the nurses in the detection of this complication of the AVF (P > 0.05). We concluded that professional experience does not influence the detection of venous stenosis and steal syndrome.     

Three-dimensional analysis of boreholes considering spatial variability of properties and poroelastoplasticity

In general, analysis of oil producing wells is carried out considering that both hydraulic and mechanical parameters of the rock mass are deterministic. Mechanical and hydraulic properties of rock masses and in particular sedimentary rock masses may show a considerable degree of spatial variability. This paper focuses on the evaluation of the three-dimensional borehole response, particularly of the plastic zone, taking into account the spatial variability of both hydraulic and mechanical properties. The analysis is performed with a developed finite element program that incorporates spatial variability, coupled fluid-mechanical effects and elastoplastic behavior of the rock mass. Examples are shown and conclusions are drawn regarding the effect of spatial variability on the three-dimensional borehole analysis.     

Using a MODFLOW grid, generated with GMS, to solve a transport problem with TOUGH2 in complex geological environments: The intertidal deposits of the Venetian Lagoon

The tides of the Venetian Lagoon generally vary between −0.5 and +0.7 m asl. Occasionally, they may reach a maximum of 1.5 m (acqua alta) and a minimum of −0.8 m asl (acqua bassa). Intertidal areas, called “barene,” exist all along the coast of the Lagoon. These areas are characterized by canals that concentrate the flow of water (and the deposition of sands) during the rising and waning of the tides, and that inundate and drain the vegetated areas found between canals (where organic-rich clays are deposited). Therefore, since the area is subject to subsidence, in time, sand dykes (the original canals) become juxtaposed to clayey dykes (the original vegetated areas). In addition, the sands form a continuous hydrogeologic network within the clays, very similar to that of a vascular system that effectively drains the whole “barena” deposits. In order to be effective, measures for monitoring, confining, or remediating the transport of pollutants through this kind of environment must explicitly take into account the geologic complexity. The same complexity must be included in the numerical models that support remediation efforts. At the moment, there appears to be no off-the-shelf graphical interface that is able to manage such complexity for TOUGH2. To attempt to solve this problem we have used a calibrated USGS-MODFLOW model, of the barena of “Passo a Campalto” in the Venetian Lagoon, developed with the GMS graphical interface. The model is made of 42 layers, which, apart from the first layer, are 0.5 m thick; the first layer has the thickness distribution of a dump found on top of the barena deposit at Passo a Campalto. Each layer consists of 100×60 square cells, for a total of 252,000 cells, only about half of which are active. Using a FORTRAN routine, we translate this grid, with all the hydrogeologic boundary conditions, into a TOUGH2 input file, and we provide the additional necessary information for running a TOUGH2 simulation. The results are promising, in that we were able to produce TOUGH2 grids with very complex geology and to run the models with success. For visualization, the results can be imported back into GMS as 3D scatter point sets, or they can be plotted with any adequate plotting software such as MatLab. Developing conceptual and numerical models with an elaborate graphical interface such as GMS effectively allows setting up complex problems while concentrating on their physics.