Export 9208 results:
Sort by: Author Title Type [ Year  (Desc)]
2015
Gralha, Catarina, João Araújo, and Miguel Goulão. "Metrics for measuring complexity and completeness for social goal models." Information Systems (2015). AbstractWebsite

Goal-oriented Requirements Engineering approaches have become popular in the Requirements Engineering community as they provide expressive modelling languages for requirements elicitation and analysis. However, as a common challenge, such approaches are still struggling when it comes to managing the accidental complexity of their models. Furthermore, those models might be incomplete, resulting in insufficient information for proper understanding and implementation. In this paper, we provide a set of metrics, which are formally specified and have tool support, to measure and analyse complexity and completeness of goal models, in particular social goal models (e.g. i⁎). Concerning complexity, the aim is to identify refactoring opportunities to improve the modularity of those models, and consequently reduce their accidental complexity. With respect to completeness, the goal is to automatically detect model incompleteness. We evaluate these metrics by applying them to a set of well-known system models from industry and academia. Our results suggest refactoring opportunities in the evaluated models, and provide a timely feedback mechanism for requirements engineers on how close they are to completing their models.

Gomes, Luís, Miguel Santos, Thiago Pereira, and Anikó Costa. "Model-Based Development of an Autonomous Sailing Yacht Controller." 2015 {IEEE} International Conference on Autonomous Robot Systems and Competitions, {ICARSC} 2015, Vila Real, Portugal, April 8-10, 2015. 2015. 103-108. Abstract

n/a

Moura, JJG, PV Bernhardt, L. B. Maia, and P. J. Gonzalez. "Molybdenum and tungsten enzymes: from Biology to chemistry and back." Journal of Biological Inorganic Chemistry. 20 (2015): 181-182. AbstractWebsite
Maia, Luisa B., Jose J. G. Moura, and Isabel Moura. "Molybdenum and tungsten-dependent formate dehydrogenases." Journal of Biological Inorganic Chemistry. 20 (2015): 287-309. AbstractWebsite
H., Liu, Pikhurko O., and Sousa Teresa. "Monochromatic Clique Decompositions of Graphs." Journal of Graph Theory. 80 (2015): 287-298. Abstractgeneral-mono-clique.pdf

Let $G$ be a graph whose edges are coloured with $k$ colours, and $\mathcal H=(H_1,\dots , H_k)$ be a $k$-tuple of graphs. A \emph{monochromatic $\mathcal H$-decomposition} of $G$ is a partition of the edge set of $G$ such that each part is either a single edge or forms a monochromatic copy of $H_i$ in colour $i$, for some $1\le i\le k$. Let $\phi_{k}(n,\mathcal H)$ be the smallest number $\phi$, such that, for every
order-$n$ graph and every $k$-edge-colouring, there is a monochromatic $\mathcal H$-decomposition with at most $\phi$ elements. Extending the previous results of Liu and Sousa [``Monochromatic $K_r$-decompositions of graphs", \emph{Journal of Graph Theory}76:89-100,2014], we solve this problem
when each graph in $\mathcal H$ is a clique and $n\ge n_0(\mathcal H)$ is sufficiently large.

Poggi, Francesca, Ana Firmino, and Miguel Amado. "Moving Forward on Sustainable Energy Transitions: The Smart Rural Model." European Journal of Sustainable Development. 4.2 (2015): 43-50 - DOI:10.14207/ejsd.2015.v4n2p43.
Kchaou, Omaya Bellaaj, Amin Sallem, Pedro Pereira, Mourad Fakhfakh, and Maria Helena Fino Multi-objective sensitivity-based optimization of analog circuits exploiting NSGA-II front ranking. Synthesis, Modeling, Analysis and Simulation Methods and Applications to Circuit Design (SMACD). Istambul, Turkey: IEEE, 2015.
Rocha, H. Múltiplas abordagens, múltiplas representações: um contributo para incrementar a relevância da representação algébrica [Multiple approaches, multiple representations: a contribute to increase the relevance of algebraic representation]. Atas do Encontro de Investigação em Educação Matemática. Bragança, Portugal: SPIEM, 2015. Abstract

A tecnologia e o impacto que esta pode ter sobre as diferentes representações utilizadas e, em particular, sobre a representação algébrica são o foco deste artigo. Procura-se assim compreender como é que o professor enquadra a representação algébrica no trabalho em sala de aula e como a procura tornar relevante para os alunos num contexto de utilização da tecnologia. As conclusões alcançadas apontam para a opção por uma estreita articulação entre as representações algébrica e gráfica e para uma criteriosa escolha de tarefas, envolvendo múltiplas abordagens, onde a representação algébrica vem disponibilizar informação fundamental e tendencialmente inacessível a partir de outras representações.

Poggi, Francesca, Ana Firmino, Miguel Amado, and Fernando Pinho. "Natural stone walls in vernacular architecture: what contribution towards Rural nZEB concept?" Bulletin de la Société Géographique de Liège. 51-66. 65.ISSN 0770-7576. 65:2 (2015).
Böhle, Knud, and António Brandão Moniz. "No Countries for Old Technology Assessment? Sketching the Efforts and Opportunities to Establish Parliamentary TA in Spain and Portugal." EconStor Open Access Articles (2015): 29-44. AbstractWebsite

If the question is whether there is a parliamentary technology assessment (PTA) unit in Portugal or Spain, the clear answer is that there is still no such unit at the central state level at the present time, neither in Portugal nor in Spain. The question then has to be modified addressing previous and current efforts to establish PTA and the current framework conditions and opportunities. Practices of PTA are framed here as a democratic innovation in the context of changes in representative democracies. Against this backdrop, the efforts and opportunities to establish PTA in Spain and Portugal are studied. By sketching these developments and outlining the opportunities in these countries, our aim is to contribute to the debate about the likelihood of a new wave of PTA in Europe (Hennen/Nierling 2014).

Morgado, M. L., and M. Rebelo. "Numerical approximation of distributed order reaction–diffusion equations." Journal of Computational and Applied Mathematics. 275 (2015): 216-227.
Viegas, João Carlos, Susana Nogueira, Daniel Aelenei, Hildebrando Cruz, Manuela Cano, and Nuno Neuparth. "Numerical evaluation of ventilation performance in children day care centres." Building Simulation. 8 (2015): 189-209. Abstract

Modelling of ventilation is strongly dependent on the physical characteristics of the building of which precise evaluation is a complex and time consuming task. In the frame of a research project, two children day care centres (CDCC) have been selected in order to measure the envelope air permeability, the flow rate of mechanical ventilation systems and indoor and outdoor temperature. The data obtained was used as input to the computer code CONTAM for ventilation simulations. The results obtained were compared with direct measurements of ventilation flow from short term measurements with CO2 tracer gas and medium term measurements with perfluorocarbon tracer (PFT) gas decay method. After validation, in order to analyse the main parameters that affect ventilation, the model was used to predict the ventilation rates for a wide range of conditions. The purpose of this assessment was to find the best practices to improve natural ventilation. A simple analytical method to predict the ventilation flow rate of rooms is also presented. The method is based on the estimation of wind effect on the room through the evaluation of an average factor and on the assessment of relevant cross section of gaps and openings combined in series or in parallel. It is shown that it may be applied with acceptable accuracy for this type of buildings when ventilation is due essentially to wind action.

Biscaia, Hugo C., Carlos Chastre, André Viegas, and Noel Franco. "Numerical modelling of the effects of elevated service temperatures on the debonding process of frp-to-concrete bonded joints." Composites Part B: Engineering. 70 (2015): 64-79. AbstractWebsite

There are many issues concerning the performance behaviour of FRP-to-concrete interfaces at elevated service temperatures (EST). At EST, i.e. slightly above the glass transition temperature (Tg), some properties associated with the FRP composites, such as the stiffness, strength or the bond characteristics, degrade. This is a crucial issue and there are only a few studies that take into account such effects on FRP-to-concrete interfaces at EST. This paper examines, through a numerical analysis, the performance of FRP-to-concrete bonded joints at EST using a new discrete model based on truss elements and shear springs. The External Bonded Reinforcement (EBR) systems subjected to EST are analyzed. The numerical discrete model was implemented in a MATLAB routine and the bond-slip curves of the interfaces at EST were obtained from a model found in literature. The numerical results revealed that the interface at EST behaves similarly to one with two equal mechanical loads applied at both ends of the FRP plate. The load-slip curves or bond stresses, strains or slippages along the bonded length obtained from several bond-slip curves at different temperatures were obtained. Two different single-lap shear tests were simulated at steady-state (steady temperature followed by load increase) and transient state (steady load followed by temperature increase). Regarding the influence of the temperature on the adhesion between the FRP and concrete, the results showed that an increase in the temperature at an earlier situation, i.e. during a period where temperature had no influence in the concrete deformations, leads to an increase in the effective bond length of the interface affecting the initial strength of the interface.

Rocha, H. O formal da matemática e o intuitivo da tecnologia: que articulação?. Atas do ProfMat 2015. Évora, Portugal: APM, 2015. Abstractpaper.pdf

A tecnologia é cada vez mais indispensável no dia-a-dia, rodeando-nos constantemente. Para os nossos alunos é uma realidade que conhecem desde sempre e que tendem a encarar com uma naturalidade descontraída e intuitiva. A facilidade de acesso à tecnologia e o modo como esta tende a enfatizar o intuitivo e a relegar para segundo plano o formal e a demonstração matemática são o foco deste artigo. Partindo da análise de uma proposta de trabalho onde alunos de 10.º ano começam por uma abordagem intuitiva apoiada na calculadora gráfica e terminam a realizar uma demonstração da conjectura que formularam, procuro discutir a problemática. As conclusões alcançadas sugerem que é possível colocar aos alunos situações onde estes se podem aperceber da vantagem de recorrer tanto a abordagens mais formais como a abordagens mais intuitivas e isto mesmo quando a tecnologia é uma realidade em sala de aula. Sugere ainda que a realização de demonstrações pode, entre outros aspectos já identificados na literatura, dar um contributo importante para a compreensão de aspectos basilares da Matemática.

Rocha, H. O formalismo matemático num contexto de utilização da tecnologia [Mathematical proof in a context of technology integration]. Atas do XXVI SIEM. Évora: APM, 2015. Abstract

The technology and how it tends to emphasize the intuitive and overshadow calculus and mathematical proof are the focus of this paper. The conclusions reached suggest that tasks where students might realize the usefulness of calculus as well as of more intuitive approaches are possible even when the technology is a reality in the classroom. They also suggest that proof may, among other things already identified in the literature, make an important contribution to the students’ understanding of fundamental aspects of mathematics.

A tecnologia e a forma como esta tende a enfatizar o intuitivo e a relegar para segundo plano o formal e a demonstração matemática são o foco deste artigo. As conclusões alcançadas sugerem que é possível colocar aos alunos situações onde estes se possam aperceber da vantagem de recorrer tanto a abordagens mais formais como a abordagens mais intuitivas e isto mesmo quando a tecnologia é uma realidade em sala de aula. Sugere ainda que a realização de demonstrações pode, entre outros aspectos já identificados na literatura, dar um contributo importante para a compreensão de aspectos basilares da Matemática.

Marques, Filipe J., Carlos A. Coelho, and Miguel de Carvalho. "On the distribution of linear combinations of independent Gumbel random variables (Supplementary Material)." Statistics and Computing. 25 (2015): 1-5. Abstract

n/a

Brás, C. P., M. Fukushima, A. N. Iusem, and J. J. Júdice. "On the Quadratic Eigenvalue Complementarity Problem over a General Convex Cone." Applied Mathematics and Computation. 271 (2015): 594-608. AbstractWebsite

The solution of the Conic Quadratic Eigenvalue Complementarity Problem (CQEiCP) is first investigated without assuming symmetry on the matrices defining the problem. A new sufficient condition for existence of solutions of CQEiCP is presented, extending to arbitrary pointed, closed and convex cones a condition known to hold when the cone is the nonnegative orthant. We also address the symmetric CQEiCP where all its defining matrices are symmetric. We show that, assuming that two of its defining matrices are positive definite, this symmetric CQEiCP reduces to the computation of a stationary point of an appropriate merit function on a convex set. Furthermore, we discuss the use of the so called Spectral Projected Gradient (SPG) algorithm for solving CQEiCP when the cone of interest is the second-order cone (SOCQEiCP). A new algorithm is designed for the computation of the projections required by the SPG method to deal with SOCQEiCP. Numerical results are included to illustrate the efficiency of the SPG method and the new projection technique in practice.

Ramos, Luís, João Lita da Silva, and João Tiago Mexia. "On the Strong Consistency of Ridge Estimates." Communications in Statistics -­ Theory and Methods (2015).
Pereira, P., F. Passos, and M. H. Fino. "Optimization-Based Design of RF-VCOs with Tapered Inductors." Performance Optimization Techniques in Analog, Mixed-Signal, and Radio-Frequency Circuit Design. Eds. M. FahkFahk, E. Tlelo-Cuautle, and M. H. Fino. IGI Global, 2015.
Hendrickx, Christophe, Scott A. Hartman, and Octávio Mateus. "An overview of non-avian theropod discoveries and classification." PalArch’s Journal of Vertebrate Palaeontology. 12.1 (2015): 1-73. Abstracthendrickx_etal_2015_non_avian_theropods_pjvp12_11.pdfWebsite

Theropods form a taxonomically and morphologically diverse group of dinosaurs that include extant birds. Inferred relationships between theropod clades are complex and have changed dramatically over the past thirty years with the emergence of cladistic techniques. Here, we present a brief historical perspective of theropod discoveries and classification, as well as an overview on the current systematics of non-avian theropods. The first scientifically recorded theropod remains dating back to the 17th and 18th centuries come from the Middle Jurassic of Oxfordshire and most likely belong to the megalosaurid Megalosaurus. The latter was the first theropod genus to be named in 1824, and subsequent theropod material found before 1850 can all be referred to megalosauroids. In the fifty years from 1856 to 1906, theropod remains were reported from all continents but Antarctica. The clade Theropoda was erected by Othniel Charles Marsh in 1881, and in its current usage corresponds to an intricate ladder-like organization of ‘family’ to ‘superfamily’ level clades. The earliest definitive theropods come from the Carnian of Argentina, and coelophysoids form the first significant theropod radiation from the Late Triassic to their extinction in the Early Jurassic. Most subsequent theropod clades such as ceratosaurs, allosauroids, tyrannosauroids, ornithomimosaurs, therizinosaurs, oviraptorosaurs, dromaeosaurids, and troodontids persisted until the end of the Cretaceous, though the megalosauroid clade did not extend into the Maastrichtian. Current debates are focused on the monophyly of deinonychosaurs, the position of dilophosaurids within coelophysoids, and megaraptorans among neovenatorids. Some recent analyses have suggested a placement of dilophosaurids outside Coelophysoidea, Megaraptora within Tyrannosauroidea, and a paraphyletic Deinonychosauria with troodontids placed more closely to avialans than dromaeosaurids.

Amado, Miguel, and Inês Ramalhete. "Parametric Elements to Modular Social Housing." Architecture_MPS: A JOURNAL OF ARCHITECTURE_MEDIA_POLITICS_SOCIETY. rchitecturemps.com/wp-content/uploads/2015/10/.25/10 (2015): 1-16.