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Publicações

Publicações por CRAS

2012

RemoteLabs Platform

Autores
Malheiro, B; Crabeel, N; Campos Neves, B;

Publicação
International Journal of Online Engineering (iJOE) - Int. J. Onl. Eng.

Abstract

2012

Personalised placement in networked video

Autores
Foss, J; Malheiro, B; Burguillo, JC;

Publicação
WWW'12 - Proceedings of the 21st Annual Conference on World Wide Web Companion

Abstract
Personalised video can be achieved by inserting objects into a video play-out according to the viewer's profile. Content which has been authored and produced for general broadcast can take on additional commercial service features when personalised either for individual viewers or for groups of viewers participating in entertainment, training, gaming or informational activities. Although several scenarios and use-cases can be envisaged, we are focussed on the application of personalised product placement. Targeted advertising and product placement are currently garnering intense interest in the commercial networked media industries. Personalisation of product placement is a relevant and timely service for next generation online marketing and advertising and for many other revenue generating interactive services. This paper discusses the acquisition and insertion of media objects into a TV video play-out stream where the objects are determined by the profile of the viewer. The technology is based on MPEG-4 standards using object based video and MPEG-7 for metadata. No proprietary technology or protocol is proposed. To trade the objects into the video play-out, a Software-as-a-Service brokerage platform based on intelligent agent technology is adopted. Agencies, libraries and service providers are represented in a commercial negotiation to facilitate the contractual selection and usage of objects to be inserted into the video play-out. Copyright is held by the International World Wide Web Conference Committee (IW3C2).

2012

RemoteLabs Platform

Autores
Crabeel, N; Neves, BC; Malheiro, B;

Publicação
iJOE

Abstract

2012

Spatial patterns of linear and nonparametric long-term trends in Baltic sea-level variability

Autores
Donner, RV; Ehrcke, R; Barbosa, SM; Wagner, J; Donges, JF; Kurths, J;

Publicação
NONLINEAR PROCESSES IN GEOPHYSICS

Abstract
The study of long-term trends in tide gauge data is important for understanding the present and future risk of changes in sea-level variability for coastal zones, particularly with respect to the ongoing debate on climate change impacts. Traditionally, most corresponding analyses have exclusively focused on trends in mean sea-level. However, such studies are not able to provide sufficient information about changes in the full probability distribution (especially in the more extreme quantiles). As an alternative, in this paper we apply quantile regression (QR) for studying changes in arbitrary quantiles of sea-level variability. For this purpose, we chose two different QR approaches and discuss the advantages and disadvantages of different settings. In particular, traditional linear QR poses very restrictive assumptions that are often not met in reality. For monthly data from 47 tide gauges from along the Baltic Sea coast, the spatial patterns of quantile trends obtained in linear and nonparametric (spline-based) frameworks display marked differences, which need to be understood in order to fully assess the impact of future changes in sea-level variability on coastal areas. In general, QR demonstrates that the general variability of Baltic sea-level has increased over the last decades. Linear quantile trends estimated for sliding windows in time reveal a wide-spread acceleration of trends in the median, but only localised changes in the rates of changes in the lower and upper quantiles.

2012

Quantile Analysis of Relative Sea-Level at the Hornbaek and Gedser Tide Gauges

Autores
Barbosa, SM; Madsen, KS;

Publicação
GEODESY FOR PLANET EARTH: PROCEEDINGS OF THE 2009 IAG SYMPOSIUM

Abstract
The quantification of the long-term variability of relative sea-level is a fundamental problem in geodesy. In the present study, quantile regression is applied for characterising the long-term variability in relative sea-level at the Gedser and Hornbaek tide gauges, in the North Sea-Baltic Sea transition zone. Quantile regression allows to quantify not only the rate of change in mean sea-level but also in extreme heights, providing a more complete description of long-term variability. At Gedser the lowest relative heights are increasing at a rate approximately 40% higher than the mean rate, while at Hornbaek the relative sea-level slopes are stable across most of the quantiles. A 30-year running window analysis shows that the linear trends display considerable decadal variability over the twentieth century for both stations.

2012

Contemporary sea level in the Chagos Archipelago, central Indian Ocean

Autores
Dunne, RP; Barbosa, SM; Woodworth, PL;

Publicação
GLOBAL AND PLANETARY CHANGE

Abstract
Long term mean sea level in the Chagos Archipelago has been relatively stable over the similar to 20 year length of the available instrumental records. Tide-gauge data from Diego Garcia (1988-2000, and 2003-2011) show no statistically significant long-term rise, whilst the rates of rise obtained from the satellite altimeter record for 1993-2011 span the range of 0.16-4.56 mm yr(-1) in the surrounding sea areas (70-74 degrees E and 4-9 degrees S) and are also consistent with a zero rate except in the far south of the region. The dominant feature is one of considerable inter-annual variability in mean sea level of up to similar to 10 cm, such that the very weak seasonal pattern of highest and lowest sea level in February and May respectively, is absent or reversed in some years. The Indian Ocean Dipole appears to exert an important influence on mean sea level in the area, with positive and negative dipole mode indices preceding periods of elevated or lowered sea levels respectively. The Chagos also lie outside the Indian Ocean cyclone belt and experience relatively low wind speeds, and there is no evidence of changes in the wind or wave environment in the past 20 years. Although in an area of seismic activity, there is no record of island subsidence, indeed on Diego Garcia minor crustal uplift of 0.63 +/- 0.28 SE mm yr(-1) has occurred between 1996 and 2009. Collectively, these results suggest that this has been a relatively stable physical environment, and that these low-lying coral islands should continue to be able to support human habitation, as they have done for much of the last 200 years. Nonetheless, future sea-level rise and its effect on the Chagos remains an important issue for further studies such as those of the Intergovernmental Panel on Climate Change.

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