2008
Authors
Barbosa, SM; Silva, ME; Fernandes, MJ;
Publication
TELLUS SERIES A-DYNAMIC METEOROLOGY AND OCEANOGRAPHY
Abstract
Sea level is a key variable in the context of global climate change. Climate-induced variability is expected to affect not only the mean sea level but also the amplitude and phase of its seasonal cycle. This study addresses the changes in the amplitude and phase of the annual cycle of coastal sea level in the extra-tropical North Atlantic. The physical causes of these variations are explored by analysing the association between fluctuations in the annual amplitude of sea level and in ancillary parameters [atmospheric pressure, sea-surface temperature and North Atlantic Oscillation (NAO) winter index]. The annual cycle is extracted through autoregressive decomposition, in order to be able to separate variations in seasonality from long-term interannual variations in the mean. The changes detected in the annual sea level cycle are regionally coherent, and related to changes in the analysed forcing parameters. At the northern sites, fluctuations in the annual amplitude of sea level are associated with concurrent changes in temperature, while atmospheric pressure is the dominant influence for most of the sites on the western boundary. The state of the NAO influences the annual variability in the Southern Bight, possibly through NAO-related changes in wind stress and ocean circulation.
2008
Authors
Barbosa, SM;
Publication
GEOPHYSICAL RESEARCH LETTERS
Abstract
Quantile regression is applied for characterizing long-term sea-level variability in the Baltic Sea from long tide gauge records. The approach allows to quantify not only variability in the mean but also in extreme heights and thus provides a more complete description of regional sea-level variability. In the Baltic, slopes in minima are similar to the classical mean-based ordinary least squares slope, but maxima exhibit larger trends, particularly at the northernmost stations, in the Gulf of Bothnia, likely associated with changes in north Atlantic atmospheric circulation and particularly regional wind patterns. Citation: Barbosa, S. M. ( 2008), Quantile trends in Baltic sea level, Geophys. Res. Lett., 35, L22704, doi: 10.1029/2008GL035182.
2008
Authors
Barbosa, SM;
Publication
HIMALAYAN GEOLOGY
Abstract
2008
Authors
Barbosa, J; Monteiro, AP;
Publication
HIGH PERFORMANCE COMPUTING FOR COMPUTATIONAL SCIENCE - VECPAR 2008
Abstract
This paper addresses the problem of scheduling multi-user jobs on clusters, both homogeneous and heterogeneous. A user job is composed by a set of dependent tasks and it is described by a direct acyclic graph (DAG). The aim is to maximize the resource usage by allowing a floating mapping of processors to a given job, instead of the common mapping approach that assigns a fixed set of processors to a user for a period of time. The simulation results show a better cluster usage. The scheduling algorithm minimizes the total length of the schedule (makespan) of a given set of parallel jobs, whose priorities are represented in a DAG. The algorithm is presented as producing static schedules although it can be adapted to a dynamic behavior as discussed in the paper.
2008
Authors
Carvalho, E; Marcos, A; Santos, MY; Espregueria Mendes, J;
Publication
IEEE COMPUTER GRAPHICS AND APPLICATIONS
Abstract
A cartographic-oriented model uses algebraic map operations to perform spatial analysis of medical data relative to the human body. A prototype system uses 3D visualization techniques to deliver analysis results. A prototype implementation suggests the model might provide the basis for a medical application tool that introduces new information insight. © 2008 IEEE.
2008
Authors
Carvalho, ES; Marcos, AF; Santos, MY; Espregueira Mendes, J; Pereira, RB;
Publication
INTERNATIONAL JOURNAL OF COMPUTER ASSISTED RADIOLOGY AND SURGERY
Abstract
Objective The main goal of the CHUB (cartographic human body) model is to introduce a cartographic approach that can assist the analysis, visualization and diagnosis of medical images and related data. Method Acartographic model is proposed as a reference framework for the development of computer systems and applications. This model accommodates subtle spatial features of these data that may facilitate diagnosis. Medical images and related data are structured into different "human-referenced" information layers. Algebraic map operations are used to combine these layers and achieve greater insights into the information content. Results Two case studies were considered to evaluate and validate the model: hydrokinetic therapy and the diagnosis of knee osteoarthritis. A prototype based on the CHUB model was implemented and two different approaches were performed to test and evaluate it. Full acceptance of the model was achieved by clinicians who used the CHUB system. Conclusion Acartographic model provides a feasible means for analyzing and visualizing medical image and related data. CHUB is a suitable model that may be used as a common framework for systems, applications and/or support tools that analyze and visualize medical images and related data (for example, in disease diagnosis).
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