The Structure of International Stock Market Returns

The behavior of international stock market returns in terms of rate of return, unconditional volatility, skewness, excess kurtosis, serial dependence and long-memory is examined. A factor analysis approach is employed to identify the underlying dimensions of stock market returns. In our approach, the factors are estimated not from the observed historical returns but from their empirical properties, without imposing any restriction about the time dependence of the observations. To identify clusters of markets and multivariate outliers, factor analysis is then used to generate factor scores. The findings suggest the existence of meaningful factors which determine the differences in terms of the dependence structure between developed and emerging market returns

On the classification of financial data with domain agnostic features

We compare a data-driven domain agnostic set of canonical features with a smaller collection of features that capture well-known stylized facts about financial asset returns. We show that these facts discriminate better different asset types than general-purpose features. Therefore, financial time series analysis is a domain where well-informed expert knowledge may not be disregarded in favor of agnostic representations of the data.info:eu-repo/semantics/publishedVersio

Modeling and simulation of photofabrication processes using unsaturated polyester resins

Several kinetic models have been proposed to simulate thermosetting cure reactions. The most complex models, based on a mechanistic approach of cure reactions, are developed based on the concepts of free radical polymerization and the mechanism of reactions with diffusion. However, mechanistic models are usually quite impractical for engineering purposes because of the difficulty in obtaining the model parameters. An alternative to these mechanistic models are the phenomenological models, formulated in terms of the degree of cure and much easier to apply. Phenomenological models have been largely used to study thermal-initiated cure reactions, although only few works used them to model the kinetics of ultraviolet-initiated cure reaction. This work proposes a photo-thermal-kinetic model to study the behavior of unsaturated polyester resins during ultraviolet-initiated cure reactions. The model considers samples with different amounts of initiator concentration and cure reactions performed under different ultraviolet light intensities. The model has been numerically solved using the finite element techniquePortuguese Foundation for Science and Technology; contract grant number: POCTI/EME/58405/2004

Bimodal information increases spontaneous interpersonal synchronization of goal directed upper limb movements

When interacting with each other, people often synchronize spontaneously their movements, e.g. during pendulum swinging, chair rocking[5], walking [4][7], and when executing periodic forearm movements[3].Although the spatiotemporal information that establishes the coupling, leading to synchronization, might be provided by several perceptual systems, the systematic study of different sensory modalities contribution is widely neglected. Considering a) differences in the sensory dominance on the spatial and temporal dimension[5] , b) different cue combination and integration strategies [1][2], and c) that sensory information might provide different aspects of the same event, synchronization should be moderated by the type of sensory modality. Here, 9 naïve participants placed a bottle periodically between two target zones, 40 times, in 12 conditions while sitting in front of a confederate executing the same task. The participant could a) see and hear, b) see , c) hear the confederate, d) or audiovisual information about the movements of the confederate was absent. The couple started in 3 different relative positions (i.e., in-phase, anti-phase, out of phase). A retro-reflective marker was attached to the top of the bottles. Bottle displacement was captured by a motion capture system. We analyzed the variability of the continuous relative phase reflecting the degree of synchronization. Results indicate the emergence of spontaneous synchronization, an increase with bimodal information, and an influence of the initial phase relation on the particular synchronization pattern. Results have theoretical implication for studying cue combination in interpersonal coordination and are consistent with coupled oscillator models.Fundação Bial (Grant 77/12) and Fundação para a Ciência e Tecnologia - FCT: SFRH/BD/8839 6/2012; EXPL/MHC - PCN/0162/2013; FCOMP - 01 - 0124 - FEDER - 022674 and PEst - C/CTM/U10264/2011; FCOMP - 01 - 0124 - FEDER - 037281 and PEst - C/EEI/LA0014/2013. This work was financed by FEDER grants through the Operational Competitiveness Program – COMPET

Thermal performance of a PCM firefighting suit considering transient periods of fire exposure, post - fire exposure and resting phases

Firefighting scenarios may be characterized by various transient periods (i.e. phases), which consist of diverse environmental conditions. Firefighters usually encounter fire exposure, post fire exposure and resting phases. Development of new and improved protective clothing must be able to provide protection throughout all these phases, as burnouts may still occur after fire exposure due to accumulation of heat in the garment. The incorporation of phase change materials (PCMs) in firefighting garments has been shown to minimize the potential of heat hazards only during fire exposure. Thus to get more knowledge on their thermal performance, in the present study, the effect of PCM incorporation in post fire and resting phases were also numerically studied. The numerical code was validated for all phases. Five potential PCM candidates were considered. Exposure phases were characterized by high- medium and low- heat flux intensities (84, 12 and 5 kW.m(-2)) with variable exposure times whilst post -exposure and resting phases where characterized by different wind speeds (i.e. ambient convective coefficients). Optimal PCM masses, times to second and third - degree burns as well as PCM suit cooling times were calculated to reflect thermal protective performance in each respective phase. The data generated allows for PCM short-listing from a set of potential PCM candidates along with its geometrical parameters, considering a wide range of characteristics of the various phases that consist a typical firefighting scenario

Análise de Movimento Não Rígido em Visão por Computador

Neste artigo são apresentadas várias metodologias actualmente existentes, no domínio da Visão por Computador, para a análise de movimento não rígido e são indicados diversos exemplos de aplicações. Assim o movimento não rígido é classificado e, para cada classe resultante, são indicadas as restrições e as condições inerentes e verificados alguns trabalhos realizados no seu âmbito. Como as questões de análise de movimento e modelização da forma se tornam inseparáveis quando se considera o movimento do tipo não rígido, a modelização sugere uma classificação possível da forma não rígida e do movimento. Assim são também apresentados modelos de forma para objectos deformáveis e indicados vários exemplos de aplicações. Com este estudo, de certo modo aprofundado, das várias metodologias, e suas aplicações, existentes no domínio da análise de movimento não rígido, espera-se contribuir para o seu desenvolvimento, dada a actual carência de boas revisões do estado da arte neste domínio.In this article several methodologies actually existent, in the Computer Vision domain, for non-rigid movement analysis are presented and several examples of applications are indicated. Thus the non-rigid movement is classified and, for each resulting class, the restrictions and the inherent conditions are presented and some works accomplished in its ambit are verified. As the questions of movement and shape analysis becomes non-separable when its considered the movement of the non-rigid type, the shape models also suggests a possible classification of the non-rigid shape and of the movement. Thus shape models for deformable objects will be presented and some examples of applications indicated. With this study, in certain way deep, of several methodologies, and its applications, existent in the domain of the non-rigid movement analysis, the authors hope to contribute for its development, given the actual lack of good state of the art revisions in this domain

Price forecasting in the day-ahead Iberian electricity market using a conjectural variations Arima model

Price forecast is a matter of concern for all participants in electricity markets, from suppliers to consumers through policy makers, which are interested in the accurate forecast of day-ahead electricity prices either for better decisions making or for an improved evaluation of the effectiveness of market rules and structure. This paper describes a methodology to forecast market prices in an electricity market using an ARIMA model applied to the conjectural variations of the firms acting in an electricity market. This methodology is applied to the Iberian electricity market to forecast market prices in the 24 hours of a working day. The methodology was then compared with two other methodologies, one called naive and the other a direct forecast of market prices using also an ARIMA model. Results show that the conjectural variations price forecast performs better than the naive and that it performs slightly better than the direct price forecast

Geodynamic evolution of the South Variscan Iberian Suture as recorded by mineral transformations

New structural, petrographic, mineralogical and geochemical data from the Beja-Acebuches Ophiolite Complex (BAOC) are presented, and reviewed together with data published elsewhere. The new data obtained shed light on questions such as: 1) the relative importance of the obduction event; 2) its geological record in the deep levels of BAOC; 3) the nature and intensity of the Variscan metamorphism and deformation during subsequent continental (arc) collision; 4) the age relationships between BAOC and the Beja Igneous Complex; and 5) by means of numerical modelling, the thermal metamorphism of the Ossa-Morena autochthonous terranes induced by the ophiolite obduction. The emerging picture is that of a fairly simple overall geological evolution for BAOC, seamlessly integrated within the evolution of the southern branch of the Iberian Variscides. Obduction of BAOC is a relatively minor early event in the general NE–SW convergence that gave rise to the orogen as seen regionally and is recorded by an anisotropic, high-temperature, metamorphic fabric at the gabbro levels and by subtle features of the chemical composition of primary minerals at the underlying peridotite level; it caused chilling of the obducted ophiolitic slab and no significant metamorphism on the autochtonous rocks of the Ossa-Morena Zone. BAOC underwent most of its deformation and (amphibolite facies) metamorphism during a later collisional event, that took place as the most primitive rocks of the Beja Igneous complex were being intruded, and whose waning stages are responsible for extensive serpentinisation of peridotites and for important aquocarbonic fluid discharges along the semibrittle–brittle shear zones meanwhile developed.info:eu-repo/semantics/publishedVersio

Modelos Deformáveis em Imagem Médica

Modelos deformáveis são actualmente bastante utilizados em imagem médica pois, através da utilização de princípios físicos, simulam de forma bastante satisfatória o comportamento dos objectos reais.Basicamente os modelos deformáveis são inicializados junto dos objectos a considerar, por processos automáticos ou semi-automáticos, e a aproximação para a posição final desejada é conseguida através de um processo de minimização de energia. Esta minimização de energia é verificada quando o modelo atinge o equilíbrio, entre as suas forças internas e as forças externas originadas pelos dados e por eventuais forças impostas pelo utilizador.Neste relatório são apresentados os fundamentos dos modelos deformáveis e indicados alguns exemplos de aplicação em imagem médica, nomeadamente na segmentação, no emparelhamento, no alinhamento e na reconstrução de dados 2D e 3D.Palavras-chave: Contornos activos, imagem médica, modelos deformáveis.Deformable models are currently very used in medical image since, through the use of physical principles, they simulate quite satisfactory the real objects behavior.Basically the deformable models are placed in the image near to the objects to be considered, by automatic or semi-automatic processes, and the approach to the desired final position is obtained through an energy minimization process. This energy minimization is verified when the model reaches the equilibrium, between its internal forces and the external forces originated by the data and eventual forces imposed by the user.In this report are presented the deformable models fundaments and indicated some application examples in medical imaging field, namely in segmentation, matching, alignment and in the reconstruction of 2D and 3D data.Keywords: Active contours, deformable models, medical image