Lito e tectono-estratigrafia da Unidade do Minho Central e Ocidental: uma proposta de reclassificação

A revisão cartográfica do sector correspondente à unidade parautóctone designada por Minho Central e Ocidental, permitiu identificar novas unidades: autóctones (formação Sobrado); parautóctones (unidades de Torre-Amonde e Vilar de Mouros) e alóctones (Unidades de Vila Mou-Covas e Arga). São propostas correlações destas unidades com outros sectores da Zona Galiza – Trás-os-Montes, nomeadamente, Celorico de Basto, Vila Pouca de Aguiar e Macedo de Cavaleiros.New geological mapping of the parauthocthonous unit of “Minho Central e Ocidental”, allowed the identification of some new units: autochthonous (Sobrado formation); parauthocthonous (TorreAmonde and Vilar de Mouros units) and allochthonous units (Vila Mou-Covas, Arga). Some correlations are established with other sector of Galiza - Trás-os-Montes Zone, namely, Celorico de Basto, Vila Pouca de Aguiar and Macedo de Cavaleiros sectors.(undefined

Time series motifs statistical significance

Time series motif discovery is the task of extracting previously unknown recurrent patterns from time series data. It is an important problem within applications that range from finance to health. Many algorithms have been proposed for the task of eficiently finding motifs. Surprisingly, most of these proposals do not focus on how to evaluate the discovered motifs. They are typically evaluated by human experts. This is unfeasible even for moderately sized datasets, since the number of discovered motifs tends to be prohibitively large. Statistical significance tests are widely used in bioinformatics and association rules mining communities to evaluate the extracted patterns. In this work we present an approach to calculate time series motifs statistical significance. Our proposal leverages work from the bioinformatics community by using a symbolic definition of time series motifs to derive each motif's p-value. We estimate the expected frequency of a motif by using Markov Chain models. The p-value is then assessed by comparing the actual frequency to the estimated one using statistical hypothesis tests. Our contribution gives means to the application of a powerful technique - statistical tests - to a time series setting.This provides researchers and practitioners with an important tool to evaluate automatically the degree of relevance of each extracted motif.(undefined

Automatically estimating iSAX parameters

The Symbolic Aggregate Approximation (iSAX) is widely used in time series data mining. Its popularity arises from the fact that it largely reduces time series size, it is symbolic, allows lower bounding and is space efficient. However, it requires setting two parameters: the symbolic length and alphabet size, which limits the applicability of the technique. The optimal parameter values are highly application dependent. Typically, they are either set to a fixed value or experimentally probed for the best configuration. In this work we propose an approach to automatically estimate iSAX’s parameters. The approach – AutoiSAX – not only discovers the best parameter setting for each time series in the database, but also finds the alphabet size for each iSAX symbol within the same word. It is based on simple and intuitive ideas from time series complexity and statistics. The technique can be smoothly embedded in existing data mining tasks as an efficient sub-routine. We analyze its impact in visualization interpretability, classification accuracy and motif mining. Our contribution aims to make iSAX a more general approach as it evolves towards a parameter-free method

Multiresolution motif discovery in time series

Time series motif discovery is an important problem with applications in a variety of areas that range from telecommunications to medicine. Several algorithms have been proposed to solve the problem. However, these algorithms heavily use expensive random disk accesses or assume the data can't into main memory. They only consider motifs at a single resolution and are not suited to interactivity. In this work, we tackle the motif discovery problem as an approximate Top-K frequent subsequence discovery problem. We fully exploit state of the art iSAX representation multiresolution capability to obtain motifs at diferent resolutions. This property yields interactivity, allowing the user to navigate along the Top-K motifs structure. This permits a deeper understanding of the time series database. Further, we apply the Top-K space saving algorithm to our frequent subsequences approach. A scalable algorithm is obtained that is suitable for data stream like applications where small memory devices such as sensors are used. Our approach is scalable and disk-eficient since it only needs one single pass over the time series database. We provide empirical evidence of the validity of the algorithm in datasets from diferent areas that aim to represent practical applications.(undefined

The role of poroelasticity on the biomechanics of the intervertebral disc : a finite element study

The major goal for the present work is to evaluate a biomimetic Finite Element (FE) model of the Intervertebral Disc (IVD). Recent studies have emphasized the importance of an accurate biomechanical modeling of the IVD, which is a highly complex biphasic medium. A novel biphasic poroelastic model was implemented and coupled with Wilson’s model (2005) for biphasic osmotic swelling behavior. Numerical tests were devoted to the analysis of the time- dependent behavior of the IVD. The results show good agreement with literature experimental data (Heuer et al., 2007 or O’Connell et al., 2011) and also with other numerical studies (Galbusera et al., 2011). In brief, this in-development IVD FE model aims to be a valuable tool to study the biomechanics of the IVD and its pathways for degeneration.Fundação para a Ciência e a Tecnologia (FCT

Association of radio polar cap brightening with bright patches and coronal holes

Radio-bright regions near the solar poles are frequently observed in Nobeyama Radioheliograph (NoRH) maps at 17 GHz, and often in association with coronal holes. However, the origin of these polar brightening has not been established yet. We propose that small magnetic loops are the source of these bright patches, and present modeling results that reproduce the main observational characteristics of the polar brightening within coronal holes at 17 GHz. The simulations were carried out by calculating the radio emission of the small loops, with several temperature and density profiles, within a 2D coronal hole atmospheric model. If located at high latitudes, the size of the simulated bright patches are much smaller than the beam size and they present the instrument beam size when observed. The larger bright patches can be generated by a great number of small magnetic loops unresolved by the NoRH beam. Loop models that reproduce bright patches contain denser and hotter plasma near the upper chromosphere and lower corona. On the other hand, loops with increased plasma density and temperature only in the corona do not contribute to the emission at 17 GHz. This could explain the absence of a one-to-one association between the 17 GHz bright patches and those observed in extreme ultraviolet. Moreover, the emission arising from small magnetic loops located close to the limb may merge with the usual limb brightening profile, increasing its brightness temperature and width.Comment: 8 pages, 6 figures, 1 table. Accepted for publication in The Astrophysical Journa

Standardization of Power-from-Shore Grid Connections for Offshore Oil & Gas Production

Offshore oil and gas (O&G) production is typically powered by local diesel engines or gas turbines. Power-from-shore (PFS) is an alternative that takes advantage of onshore renewable production and reduces greenhouse emissions but is limited to bespoke projects that are tailored to the characteristics of each site. This lack of repetition leads to an increase in the construction risk, delivery time, and lifecycle costs, therefore limiting their large-scale deployment. Furthermore, the absence of standardized designs is also notorious in mature applications such as offshore wind farms (OWF) despite their long-standing track record, with the negative consequences extensively covered in the literature. This research paper addresses offshore transmission standardization in two parts. First, by providing the scientific community with a review of the existing offshore O&G production and substations and secondly, by outlining a lean optioneering algorithm for the cost-optimized and technically feasible selection of the key design criteria. The exercise is centred on the main limiting component of the transmission systems—the cables. As such, it addresses their operational range and the cost to calculate the most effective configuration in terms of voltage and rated power. The end goal, based on the spread of connection proposals, is to cluster the candidates to a limited set of grid connection options, the achievement of which the model has been shown to be adequate.info:eu-repo/semantics/publishedVersio

Projecto TerminUM

O projecto TerminUM tem como objectivos principais o estudo, experimentação e a criação de recursos na área dos corpora paralelos, terminologia (descritiva) e recursos multilingues ligados a corpora. * fazer extracção tão automática quanto possível de corpora a partir da web; * fazer extracção de dicionários, de terminologia e de outros recursos ligados à tradução; * criar e interligar as ferramentas desenvolvidas; * criar e disponibilizar: (1) listas de Bitextos, corpora e corpora paralelos, (2) ferramentas de criação e transformação de corpora, (3) recursos multilingues derivados/ligados a corpora. Nesta apresentação serão abordadas algumas tarefas presentemente a decorrer no âmbito do projecto, nomeadamente: 1. ciclo de vida da construção e transformação de corpora; 2. resumo das ferramentas desenvolvidas (e em desenvolvimento); 3. construção de corpora paralelos tomando como base legendas de filmes (subtitles), ficheiro de internacionalização (mensagens de software .po) e ficheiros de memórias de tradução (TMX); 4. animação de corpora paralelos via web (criação de motores de consulta usando diversas ferramentas)

Reversible trans-cis photoisomerization of new pyrrolidene heterocyclic imines

A series of novel pyrrolidene imines bearing functionalized aryl or naphthyl moieties was synthesized and their photochromic properties studied by UV spectroscopy. UV irradiation of these heterocyclic Schiff bases at room temperature promotes the trans-cis photoisomerization of the C=N double bond with formation of a variable amount of the cis-isomer that, in the absence of light, returns thermally to the original form in few seconds. The thermal cis-trans re-isomerization of these molecular switches is much more slower than for the common benzylidene aniline-type imines, allowing the observation of the photochromic phenomena at room temperature. Strong electron-donor substituents in the para-position of the aniline part of the molecule decreases even more the kinetics of the thermal cis-trans re-isomerization leading to a manifest change in the UV spectrum.Fundação para a Ciência e a Tecnologia (FCT