Analysis domain model for shared virtual environments

The field of shared virtual environments, which also encompasses online games and social 3D environments, has a system landscape consisting of multiple solutions that share great functional overlap. However, there is little system interoperability between the different solutions. A shared virtual environment has an associated problem domain that is highly complex raising difficult challenges to the development process, starting with the architectural design of the underlying system. This paper has two main contributions. The first contribution is a broad domain analysis of shared virtual environments, which enables developers to have a better understanding of the whole rather than the part(s). The second contribution is a reference domain model for discussing and describing solutions - the Analysis Domain Model

The Framework “Glacial and periglacial landforms and deposits” in the scope of the Portuguese Geological Heritage Inventory

“Geoformas, depósitos glaciários e periglaciários” é um dos contextos geológicos considerados no âmbito da inventariação em curso do património geológico em território nacional. Apesar da reduzida expressão geográfica que as geoformas, os depósitos glaciários e periglaciários têm em Portugal, é-lhes reconhecida importância científica, também por essa via e por resultarem de processos morfodinâmicos raros nas condições climáticas actualmente existentes em Portugal. Após uma avaliação de potenciais geossítios com base em critérios de valor científico, foram seleccionados dezasseis como possuindo relevância nacional.“Glacial and periglacial landforms and deposits” is one of the frameworks included in the ongoing geological heritage national inventory. The scientific value of these features is connected with the occurrence of relevant evidences of Quaternary glaciations in the higher mountains of the country like erosion landforms (U shaped valleys, cirques), depositional landforms (moraines) and deposits (subglacial tills). Sixteen geosites with national relevance were selected after a potential geosites assessment focused in scientific criteria.Este trabalho é apoiado pela Fundação para a Ciência e a Tecnologia, através do financiamento plurianual do CGUP e do projecto de investigação “Identificação, caracterização e conservação do património geológico: uma estratégia de geoconservação para Portugal” (PTDC/CTEGEX/64966/2006).info:eu-repo/semantics/publishedVersio

Geoheritage of Portugal as the support for nature conservation and land-use planning

O inventário nacional do património geológico reúne os principais geossítios em Portugal com elevado valor científico e que representam a geodiversidade nacional, permitindo compreender a história e a evolução geológica do nosso território. O inventário, disponível na internet, é uma ferramenta obrigatória para todos aqueles que se dedicam a ações de conservação da natureza, de ordenamento do território e a estudos de impacte ambiental.The national inventory of geoheritage comprehends the main Portuguese geosites with high scientific value. These geosites represent the national geodiversity and allow the understanding of the geological evolution of the Portuguese territory. The inventory is available on-line and constitutes a fundamental tool to support nature conservation, land-use planning and environmental impact assessment actions.Trabalho integrado no projeto estratégico (PEst-OE/CTE/UI0039/2014) do Centro de Geologia da Universidade do Porto, apoiado pela Fundação para a Ciência e Tecnologia

Accessibility and visually impaired users

Internet accessibility for the visually impaired community is still an open issue. Guidelines have been issued by the W3C consortium to help web designers to improve web site accessibility. However several studies show that a significant percentage of web page creators are still ignoring the proposed guidelines. Several tools are now available, general purpose, or web specific, to help visually impaired readers. But is reading a web page enough? Regular sighted users are able to scan a web page for a particular piece of information at high speeds. Shouldn't visually impaired readers have the same chance? This paper discusses some features already implemented to improve accessibility and presents a user feedback report regarding the AudioBrowser, a talking browser. Based on the user feedback the paper also suggests some avenues for future work in order to make talking browsers and screen readers compatible.The research reported in here was supported by SNRIP (The Portuguese National Secretariat of Rehabilitation and Integration for the Disabled) under program CITE 2001, and also FCT (Portuguese Foundation for Science and Technology) and POSI/2001 (Operational Program for the Information Society) with funds partly awarded by FEDER

Syntgen: A system to generate temporal networks with user specified topology

Network representations can help reveal the behavior of complex systems. Useful information can be derived from the network properties and invariants, such as components, clusters or cliques, as well as from their changes over time. The evolution of clusters of nodes (or communities) is one of the major focus of research. However, the time dimension increases complexity, introducing new constructs and requiring novel and enhanced algorithms. In spite of recent improvements, the relative scarcity of timestamped representations of empiric networks, with known ground truth, hinders algorithm validation. A few approaches have been proposed to generate synthetic temporal networks that conform to static topological specifications while in general adopting an ad-hoc approach to temporal evolution. We believe there is still a need for a principled synthetic network generator that conforms to problem domain topological specifications from a static as well as temporal perspective. Here we present such a system. The unique attributes of our system include accepting arbitrary node degree and cluster size distributions and temporal evolution under user control, while supporting tunable joint distribution and temporal correlation of node degrees. Theoretical contributions include the analysis of conditions for "graphability" of sequences of inter and intra cluster node degrees and cluster sizes and the development of a heuristic to search for the cluster membership of nodes that minimizes the shared information distance between clusterings. Our work shows that this system is capable of generating networks under user controlled topology with up to thousands of nodes and hundreds of clusters with strong topology adherence. Much larger networks are possible with relaxed requirements. The generated networks support algorithm validation as well as problem domain analysis

Erratum to: Designation of Natural Monuments by the Local Administration: the Example of Viana Do Castelo Municipality and its Engagement with Geoconservation (NW Portugal)

The original version of this article unfortunately contained a mistake. The four occurrences of the word “geopark” were incorrect and should be replaced with “geological park”

On the black hole mass decomposition in nonlinear electrodynamics

Abstract In the weak field limit of nonlinear Lagrangians for electrodynamics, i.e. theories in which the electric fields are much smaller than the scale (threshold) fields introduced by the nonlinearities, a generalization of the Christodoulou–Ruffini mass formula for charged black holes is presented. It proves that the black hole outer horizon never decreases. It is also demonstrated that reversible transformations are, indeed, fully equivalent to constant horizon solutions for nonlinear theories encompassing asymptotically flat black hole solutions. This result is used to decompose, in an analytical and alternative way, the total mass-energy of nonlinear charged black holes, circumventing the difficulties faced to obtain it via the standard differential approach. It is also proven that the known first law of black hole thermodynamics is the direct consequence of the mass decomposition for general black hole transformations. From all the above we finally show a most important corollary: for relevant astrophysical scenarios nonlinear electrodynamics decreases the extractable energy from a black hole with respect to the Einstein–Maxwell theory. Physical interpretations for these results are also discussed

A model for pavement temperature prediction

A finite element model has been developed to calculate the temperature of a pavement located in the Northeast of Portugal. The goal of the case study presented in this paper is the validation of this model. Input data to the model are the hourly values for solar radiation and temperature, and mean daily values of wind speed obtained from a meteorological station. The thermal response of a multilayered pavement structure is modeled using a transient thermal analysis for four months time-period (December 2003 - April 2004) and the analysis was initiated with the full depth constant initial temperature obtained from field measurements. During these four months, pavement temperature was measured at a new pavement section, located at IP4 main road, near Bragança, in the north of Portugal. At that location, seven thermocouples were installed in the AC layers, at seven different depths. These pavement data was used to validate this simulation model, by comparing model calculated data with measured pavement temperatures. As conclusion, the 3-D finite-element analysis proved to be an interesting tool to simulate the transient behavior of asphalt concrete pavements. The suggested simulation model can predict the pavement temperature at different levels of bituminous layers with a good accuracy.Instituto de Estradas de Portugal, Direcção de Bragança

Consideração das variações de temperatura no comportamento à reflexão de fendas dos reforços de pavimentos

O reforço de pavimentos constitui uma técnica de conservação estrutural na qual se baseiam as estratégias de conservação mais utilizadas na reabilitação dos pavimentos, visando a reposição da sua capacidade estrutural. Quando o reforço é aplicado sobre pavimentos fendilhados ocorre normalmente um mecanismo de ruína caracterizado pela propagação das fendas do pavimento existente para as camadas de reforço, designado por reflexão de fendas. No estudo que se apresenta, procedeu-se a uma avaliação, do efeito das variações de temperatura na ocorrência do mecanismo da reflexão de fendas, considerando a acção actuando isoladamente e actuando conjugada com o efeito da acção do tráfego numa mistura betuminosa com betume-borracha e numa mistura convencional aplicada em reforço de pavimentos. Conclui-se que a ocorrência de variações de temperatura nos pavimentos conduz ao agravamento do fenómeno da propagação de fendas, levando à ruína prematura dos reforços. Por fim apresenta-se uma proposta para a inclusão do efeito da temperatura no dimensionamento de reforços de pavimentos

The Soccer Game, bit by bit: An information-theoretic analysis

We modeled the dynamics of a soccer match based on a network representation where players are nodes discretely clustered into homogeneous groups. Players were grouped by physical proximity, supported by the intuitive notion that competing and same-team players use relative position as a key tactical tool to contribute to the team's objectives. The model was applied to a set of matches from a major European national football league, with players' coordinates sampled at 10Hz, resulting in approx. 60,000 network samples per match. We took an information theoretic approach to measuring distance between samples and used it as a proxy for the game dynamics. Significant correlations were found between measurements and key match events that are empirically known to result in players jostling for position, such as when striving to get unmarked or to mark. These events increase the information distance, while breaks in game play have the opposite effect. By analyzing the frequency spectrum of players' cluster transitions and their corresponding information distance, it is possible to build a comprehensive view of player's interactions, useful for training and strategy development. This analysis can be drilled down to the level of individual players by quantifying their contribution to cluster breakup and emergence, building an overall multi-level map that provides insights into the game dynamics, from the individual player, to the clusters of interacting players, all the way to the teams and their matches.Comment: 18 pages, 9 figure