10 resultados para cross presentation

em Instituto Politécnico do Porto, Portugal


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Critical Infrastructures became more vulnerable to attacks from adversaries as SCADA systems become connected to the Internet. The open standards for SCADA Communications make it very easy for attackers to gain in-depth knowledge about the working and operations of SCADA networks. A number of Intenrnet SCADA security issues were raised that have compromised the authenticity, confidentiality, integrity and non-repudiation of information transfer between SCADA Components. This paper presents an integration of the Cross Crypto Scheme Cipher to secure communications for SCADA components. The proposed scheme integrates both the best features of symmetric and asymmetric encryptiontechniques. It also utilizes the MD5 hashing algorithm to ensure the integrity of information being transmitted.

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An experimental and Finite Element study was performed on the bending behaviour of wood beams of the Pinus Pinaster species repaired with adhesively-bonded carbon–epoxy patches, after sustaining damage by cross-grain failure. This damage is characterized by crack growth at a small angle to the beams longitudinal axis, due to misalignment between the wood fibres and the beam axis. Cross-grain failure can occur in large-scale in a wood member when trees that have grown spirally or with a pronounced taper are cut for lumber. Three patch lengths were tested. The simulations include the possibility of cohesive fracture of the adhesive layer, failure within the wood beam in two propagation planes and patch interlaminar failure, by the use of cohesive zone modelling. The respective cohesive properties were estimated either by an inverse method or from the literature. The comparison with the tests allowed the validation of the proposed methodology, opening a good perspective for the reduction of costs in the design stages of these repairs due to extensive experimentation.

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To meet the increasing demands of the complex inter-organizational processes and the demand for continuous innovation and internationalization, it is evident that new forms of organisation are being adopted, fostering more intensive collaboration processes and sharing of resources, in what can be called collaborative networks (Camarinha-Matos, 2006:03). Information and knowledge are crucial resources in collaborative networks, being their management fundamental processes to optimize. Knowledge organisation and collaboration systems are thus important instruments for the success of collaborative networks of organisations having been researched in the last decade in the areas of computer science, information science, management sciences, terminology and linguistics. Nevertheless, research in this area didn’t give much attention to multilingual contexts of collaboration, which pose specific and challenging problems. It is then clear that access to and representation of knowledge will happen more and more on a multilingual setting which implies the overcoming of difficulties inherent to the presence of multiple languages, through the use of processes like localization of ontologies. Although localization, like other processes that involve multilingualism, is a rather well-developed practice and its methodologies and tools fruitfully employed by the language industry in the development and adaptation of multilingual content, it has not yet been sufficiently explored as an element of support to the development of knowledge representations - in particular ontologies - expressed in more than one language. Multilingual knowledge representation is then an open research area calling for cross-contributions from knowledge engineering, terminology, ontology engineering, cognitive sciences, computational linguistics, natural language processing, and management sciences. This workshop joined researchers interested in multilingual knowledge representation, in a multidisciplinary environment to debate the possibilities of cross-fertilization between knowledge engineering, terminology, ontology engineering, cognitive sciences, computational linguistics, natural language processing, and management sciences applied to contexts where multilingualism continuously creates new and demanding challenges to current knowledge representation methods and techniques. In this workshop six papers dealing with different approaches to multilingual knowledge representation are presented, most of them describing tools, approaches and results obtained in the development of ongoing projects. In the first case, Andrés Domínguez Burgos, Koen Kerremansa and Rita Temmerman present a software module that is part of a workbench for terminological and ontological mining, Termontospider, a wiki crawler that aims at optimally traverse Wikipedia in search of domainspecific texts for extracting terminological and ontological information. The crawler is part of a tool suite for automatically developing multilingual termontological databases, i.e. ontologicallyunderpinned multilingual terminological databases. In this paper the authors describe the basic principles behind the crawler and summarized the research setting in which the tool is currently tested. In the second paper, Fumiko Kano presents a work comparing four feature-based similarity measures derived from cognitive sciences. The purpose of the comparative analysis presented by the author is to verify the potentially most effective model that can be applied for mapping independent ontologies in a culturally influenced domain. For that, datasets based on standardized pre-defined feature dimensions and values, which are obtainable from the UNESCO Institute for Statistics (UIS) have been used for the comparative analysis of the similarity measures. The purpose of the comparison is to verify the similarity measures based on the objectively developed datasets. According to the author the results demonstrate that the Bayesian Model of Generalization provides for the most effective cognitive model for identifying the most similar corresponding concepts existing for a targeted socio-cultural community. In another presentation, Thierry Declerck, Hans-Ulrich Krieger and Dagmar Gromann present an ongoing work and propose an approach to automatic extraction of information from multilingual financial Web resources, to provide candidate terms for building ontology elements or instances of ontology concepts. The authors present a complementary approach to the direct localization/translation of ontology labels, by acquiring terminologies through the access and harvesting of multilingual Web presences of structured information providers in the field of finance, leading to both the detection of candidate terms in various multilingual sources in the financial domain that can be used not only as labels of ontology classes and properties but also for the possible generation of (multilingual) domain ontologies themselves. In the next paper, Manuel Silva, António Lucas Soares and Rute Costa claim that despite the availability of tools, resources and techniques aimed at the construction of ontological artifacts, developing a shared conceptualization of a given reality still raises questions about the principles and methods that support the initial phases of conceptualization. These questions become, according to the authors, more complex when the conceptualization occurs in a multilingual setting. To tackle these issues the authors present a collaborative platform – conceptME - where terminological and knowledge representation processes support domain experts throughout a conceptualization framework, allowing the inclusion of multilingual data as a way to promote knowledge sharing and enhance conceptualization and support a multilingual ontology specification. In another presentation Frieda Steurs and Hendrik J. Kockaert present us TermWise, a large project dealing with legal terminology and phraseology for the Belgian public services, i.e. the translation office of the ministry of justice, a project which aims at developing an advanced tool including expert knowledge in the algorithms that extract specialized language from textual data (legal documents) and whose outcome is a knowledge database including Dutch/French equivalents for legal concepts, enriched with the phraseology related to the terms under discussion. Finally, Deborah Grbac, Luca Losito, Andrea Sada and Paolo Sirito report on the preliminary results of a pilot project currently ongoing at UCSC Central Library, where they propose to adapt to subject librarians, employed in large and multilingual Academic Institutions, the model used by translators working within European Union Institutions. The authors are using User Experience (UX) Analysis in order to provide subject librarians with a visual support, by means of “ontology tables” depicting conceptual linking and connections of words with concepts presented according to their semantic and linguistic meaning. The organizers hope that the selection of papers presented here will be of interest to a broad audience, and will be a starting point for further discussion and cooperation.

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The English article system is actually so complex that it presents many challenges for most non-native learners of English. The main difficulty of Portuguese learners, despite the numerous similarities between the two article systems, is noticeable in a marked tendency to produce the definite article where native speakers of English would not use it. This article reports the results of a cross-sectional study which examined the English definite article overproduction by a group of 12 Portuguese EFL learners with at least seven years of English instruction. The prediction is that these learners will exhibit evidence of transferring L1 features to their interlanguage when they overuse the definite article. The data were collected by means of a gap-filling task and a composition. The results found, as predicted, that these learners overused the in generic contexts. It is argued that this overuse is directly tied to and can be explained by transfer to somewhere and conceptual transfer principles.

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Objective Patient-centredness has become an important aspect of health service delivery; however, there are a limited number of studies that focus on this concept in the domain of hearing healthcare. The objective of this study was to examine and compare audiologists’ preferences for patient-centredness in Portugal, India and Iran. Design The study used a cross-sectional survey design with audiologists recruited from three different countries. Participants A total of 191 fully-completed responses were included in the analysis (55 from Portugal, 78 from India and 58 from Iran). Main outcome measure The Patient–Practitioner Orientation Scale (PPOS). Results PPOS mean scores suggest that audiologists have a preference for patient-centredness (ie, mean of 3.6 in a 5-point scale). However, marked differences were observed between specific PPOS items suggesting these preferences vary across clinical situations. A significant level of difference (p<0.001) was found between audiologists’ preferences for patient-centredness in three countries. Audiologists in Portugal had a greater preference for patient-centredness when compared to audiologists in India and Iran, although no significant differences were found in terms of age and duration of experience among these sample populations. Conclusions There are differences and similarities in audiologists’ preferences for patient-centredness among countries. These findings may have implications for the training of professionals and also for clinical practice in terms of optimising hearing healthcare across countries.

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Objective The aim of this study was to determine tympanometric values of children who attend Oporto daycare centers and further analyze any relations with host and environmental factors. Methods Cross sectional study in a randomly selected sample of 117 daycare children up-to 3-years old from Oporto. Tympanometric measures were collected. Results Children presented in left ear (LE) a mean peak pressure (PP) of −156.53 daPa and a mean compliance of 0.16 cm3. Right ear (RE) revealed a PP of −145.61 daPa and a compliance of 0.19 cm3. Normal tympanograms (type A) had a lower frequency than abnormal tympanograms (type B and type C). There was a positive association between age and compliance (LE: p = 0.016; RE: p = 0.013) and between the presence of rhinorrhea and PP (LE: p = 0.002; RE: p < 0.05). Abnormal tympanograms were more frequent in Spring (RE: p = 0.009), in younger children (LE: p = 0.03) and in children that had rhinorrhea (LE: p = 0.002; RE: p = 0.044). Healthy children had a mean PP of −125.19 daPa and a mean compliance of 0.21 cm3 in LE and a mean PP of −144.27 daPa and a mean compliance of 0.22 cm3 in RE. Conclusion Tympanometric measures presented in this paper may be applicable to Oporto daycare children up-to 3 years-old. Most of daycare children revealed abnormal tympanograms. Age, rhinorrhea and season influenced children's middle-ear condition.

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Trabalho académico com o objetivo do autor desenvolver um estudo prévio e um projeto de uma travessia sobre o rio Lima, na cidade de Viana do Castelo constituída por uma ponte de tirantes rodoferroviária. O projeto académico visa, também, desenvolver e compreender: os conceitos básicos, as metodologias de conceção, e o funcionamento de estruturas desse género. O motivo principal da escolha do tema é a necessidade de uma alternativa à ponte Eiffel em Viana do Castelo, e juntando o facto de em Portugal não existir nenhuma obra de arte de tirantes rodoferroviária até ao presente, seria interessante estudar e projetar uma estrutura rodoferroviária de tirantes. Das diversas possibilidades de sistemas estruturais estudados, adotou-se uma ponte que acomodará 4 vias rodoviárias e 2 vias ferroviárias, com um desenvolvimento total de 660 metros, constituída por dois vãos laterais com 165 metros cada um, e com um vão central de 330 metros. A obra de arte será em semi-leque com dois planos de tirantes, ancorados a duas torres de betão em Y invertido de altura aproximadamente de 110 metros. O tabuleiro será duplo misto aço-betão, constituído por duas vigas trianguladas do tipo Warren, e por carlingas, afastadas entre si de 15 metros com secções tubulares metálicas de espessura variável. As carlingas ao nível superior suportam a laje de betão, que constitui a rodovia, e inferiormente, suportam outra laje de betão para a parte ferroviária. O trabalho inicia-se com o enquadramento conceptual geral da envolvente da obra de arte, seguidamente com apresentação da evolução histórica ao longo do tempo das pontes de tirantes, e à apresentação de algumas pontes rodoferroviárias de tirantes. É realizada uma análise preliminar, onde se estudam as restrições, as condicionantes, o local de implantação, e o sistema da configuração geométrica a adotar na conceção estrutural. São descritos todos os tipos de materiais, equipamentos a utilizar, bem como as suas características mecânicas necessárias para o cálculo estrutural. A quantificação das ações e das combinações de cálculo efetuaram-se de acordo com as normas em vigor nacionais e europeias, designadamente os Eurocódigos das várias especialidades e o Regulamento de Segurança e Ações para Estruturas de Edifícios e Pontes. Efetuou-se um pré-dimensionamento e uma otimização de vários sistemas estruturais possíveis de todos os elementos estruturais, tendo em conta variáveis de estudo como a economia e a resistência estrutural das secções, por forma a chegar à solução final. A estrutura foi discretizada e analisada num modelo estático tridimensional num programa de cálculo automático. A análise de resultados foi efetuada longitudinalmente para a verificação dos Estados Limites Últimos e Estados Limites de Utilização dos elementos estruturais que constituem a ponte. Foi ainda efetuada uma estimativa orçamental da ponte no rio Lima na cidade de Viana do Castelo.

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A criação de infraestruturas passa pela construção de estradas que ligam pontos estratégicos, permitindo acesso a bens e serviços, de forma cómoda e segura. No desenvolvimento deste trabalho é abordado o estudo e projeto de uma variante urbana no concelho de Cinfães, nas especificidades de traçado, pavimentos e sinalização. Inicia-se por uma apresentação sobre o trabalho, os objetivos, estrutura e metodologia utilizada na sua elaboração. São apresentados os softwares utilizados, como editores de imagem (Google Earth, Microsoft ICE e Caesium) que permitem obter e trabalhar imagens panorâmicas, o Civil 3D que possibilita a realização ágil de um projeto de vias, e o Alize-LCPC que determina as caraterísticas de dimensionamento de um pavimento flexível. São apresentados os estudos necessários para a construção da variante em questão passando pela localização da via, o trabalho sobre o levantamento topográfico fornecido pela Câmara Municipal, condicionantes de traçado e serviços afetados. Posteriormente, são abordados alguns conceitos teóricos como geometria do traçado, velocidade, tráfego e visibilidade. Descrevem-se as caraterísticas geométricas de infraestruturas rodoviárias a conhecer anteriormente à realização de um projeto de execução de uma via, como o traçado em planta (alinhamentos retos, curvas, raios, sobreelevação, sobrelargura), perfil longitudinal (trainéis, inclinações, concordâncias verticais) e perfil transversal (faixa de rodagem, bermas, valetas e taludes). É realizada ainda uma apresentação sobre os elementos integrantes de uma plataforma rodoviária e passeio, os seus critérios de dimensionamento, como caraterização do tráfego, temperaturas de serviço e deformações, assim como os elementos teóricos para o estudo de drenagem (período de retorno, precipitação e tipos de dispositivos). São ainda apresentadas as caraterísticas gerais de um projeto de sinalização e segurança, enunciando as marcas rodoviárias e a sinalização vertical. Termina-se apresentando as soluções encontradas e os meios utilizados, para a elaboração do projeto de uma via nova, alargamento de via existente e requalificação de pavimento de um troço de ligação à EN222, expondo ainda as conclusões obtidas na realização do projeto com propostas para desenvolvimento futuros.

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Real-time monitoring applications may be used in a wireless sensor network (WSN) and may generate packet flows with strict quality of service requirements in terms of delay, jitter, or packet loss. When strict delays are imposed from source to destination, the packets must be delivered at the destination within an end-to-end delay (EED) hard limit in order to be considered useful. Since the WSN nodes are scarce both in processing and energy resources, it is desirable that they only transport useful data, as this contributes to enhance the overall network performance and to improve energy efficiency. In this paper, we propose a novel cross-layer admission control (CLAC) mechanism to enhance the network performance and increase energy efficiency of a WSN, by avoiding the transmission of potentially useless packets. The CLAC mechanism uses an estimation technique to preview packets EED, and decides to forward a packet only if it is expected to meet the EED deadline defined by the application, dropping it otherwise. The results obtained show that CLAC enhances the network performance by increasing the useful packet delivery ratio in high network loads and improves the energy efficiency in every network load.