Evaluation of recommender systems in streaming environments

Evaluation of recommender systems is typically done with finite datasets. This means that conventional evaluation methodologies are only applicable in offline experiments, where data and models are stationary. However, in real world systems, user feedback is continuously generated, at unpredictable rates. Given this setting, one important issue is how to evaluate algorithms in such a streaming data environment. In this paper we propose a prequential evaluation protocol for recommender systems, suitable for streaming data environments, but also applicable in stationary settings. Using this protocol we are able to monitor the evolution of algorithms' accuracy over time. Furthermore, we are able to perform reliable comparative assessments of algorithms by computing significance tests over a sliding window. We argue that besides being suitable for streaming data, prequential evaluation allows the detection of phenomena that would otherwise remain unnoticed in the evaluation of both offline and online recommender systems.Comment: Workshop on 'Recommender Systems Evaluation: Dimensions and Design' (REDD 2014), held in conjunction with RecSys 2014. October 10, 2014, Silicon Valley, United State

Safety verification in non-linear analyses: the problem with 2nd order effects evaluation

Comunicação apresentada em First FIB Congress - "Concrete Structures in the 21st Century", Osaka, Japão, 13-19 outubro 200

Adhesion in Restorative Dentistry

Bonding agents play a crucial role in the effective sealing and retention of resin-based composite restorations, which have been increasingly placed and replaced by dentists in many countries around the world. In fact, direct adhesive restoration with composite resins has become the procedure of choice for the treatment of anterior and posterior teeth. However, long-term durability of those restorations may be compromised due to progressive loss of the integrity of adhesive interfaces. This means that no adhesive strategy is free from technique sensitivity. The specificity and proportion of different constitutive molecules, the interaction between them and substrates can differ greatly from one class of adhesive system to another, which can affect bond quality. Protocol simplification has been an inevitable trend that has boosted the use of self-etching and universal systems in adhesive dentistry. However, there is a lack of randomized clinical trials to prove the effectiveness of these systems. This chapter gives an overview of the most important issues in dental adhesion and adhesive systems, as well, discussing their composition and clinical use

O processo de Bolonha na ESTBarreiro/IPS

Apresentação em I Encontro do Colégio de Engenharia Civil, da Associação Nacional de Engenheiros Técnicos (ANET), Lisboa, 2 de Junho de 200

A investigação no IPS

Comunicação apresentada em I Congresso IPS, Setúbal, 20 a 22 maio 200

Modelling the behaviour of the bonding of fibre reinforced concrete at the plate end

Comunicação apresentada em International Symposium Polymers in Concrete (ISPIC 2006), Guimarães, 2006In this paper, the finite element method is used to analyse the behaviour of concrete externally strengthened by fibre reinforced polymers (FRP). This model aims to analyse the stress distribution in the FRP-concrete interface at the plate end of a bending beam. The behaviour of the concrete-poxy-FRP arrangement is modelled with interface elements with initial zero thickness, using a discrete crack approach. A localized damage model is adopted for the interface and a parametric study is performed to approximate the material parameters adopted. The importance of each parameter is assessed. This model is subsequently verified using experimental data collected from the literature. Finally, a proposal is made concerning the adoption of a relation GF II/GF for the interface behaviour. Mention is also made to some of the main mathematical models found in the literature, which are compared to the present approach

Modelling the behaviour of reinforced concrete beams strengthened with FRP

Comunicação apresentada em III European Conference on Computational Mechanics Solids, Structures and Coupled Problems in Engineering, Lisbon, 5–8 June 2006The strengthening of reinforced concrete structures with fiber reinforced polymers (FRP) is particularly attractive due to their mechanical properties. The understanding of the premature failure modes is of great importance. Since rupture is frequently found to occur at the interface FRP concrete, there is a clear need to study the nature of the bonding so as to develop techniques to permit its design modeling. The stress distribution in shear test models does not precisely match the one obtained in flexural reinforcement; in the latter, according to various authors [1, 2], in addition to the stresses tangential to the interface, normal stresses are also important. In this paper, a numerical model is presented to describe the behavior of reinforced concrete beams strengthened with FRP. This model is based on previous studies focused both on: i) the distribution of shear stresses at the interface FRP concrete and on ii) the stress concentration at the plate ends in flexural models. Furthermore, the importance of the flexural cracks in the premature rupture of the element is also analyzed. The behavior of reinforced c concrete beams strengthened with both FRP laminates and sheets is considered. The FRP epoxy concrete arrangement and the flexural cracks are modeled with interface elements with initial zero thickness, using a discrete approach and a localized damage model. A softening behavior is adopted to simulate the stress transfer along the FRP- -concrete interface. The importance of considering the mixed mode of fracture is discussed. Mention is also made to some of the main mathematical models found in the literature

Fairness and Diversity in Information Access Systems

Among the seven key requirements to achieve trustworthy AI proposed by the High-Level Expert Group on Artificial Intelligence (AI-HLEG) established by the European Commission (EC), the fifth requirement ("Diversity, non-discrimination and fairness") declares: "In order to achieve Trustworthy AI, we must enable inclusion and diversity throughout the entire AI system's life cycle. [...] This requirement is closely linked with the principle of fairness". In this paper, we try to shed light on how closely these two distinct concepts, diversity and fairness, may be treated by focusing on information access systems and ranking literature. These concepts should not be used interchangeably because they do represent two different values, but what we argue is that they also cannot be considered totally unrelated or divergent. Having diversity does not imply fairness, but fostering diversity can effectively lead to fair outcomes, an intuition behind several methods proposed to mitigate the disparate impact of information access systems, i.e. recommender systems and search engines.Comment: Presented at the European Workshop on Algorithmic Fairness (EWAF'23) Winterthur, Switzerland, June 7-9, 202

Influence of cross section geometry on the confinement of reinforced concrete columns with CFRP composites

Comunicação apresentada em International Symposium Polymers in Concrete (ISPIC 2006), Guimarães, 2006Confinement effectiveness of externally bonded FRP jackets depends on different parameters namely type of concrete, steel reinforcement, FRP jacket stiffness (type of FRP, number of plies and design of wrap), shape of cross section, radius of corners for non-circular sections, and loading conditions. In order to investigate the effect of some of these parameters on the axial behavior of columns under compression and to quantify the level of confinement exerted on the concrete core, an experimental program has been developed. The experimental research consisted of a sequence of axial compressive tests on cylinders and square prisms. Prisms were divided into three representative groups: sharpedged sections and sections with rounded corners with corner radii equal to either 20mm or 38mm. The results presented in this paper are for the columns which were wrapped with two plies of unidirectional carbon fibers

A gravação audiovisual como ferramenta de apoio ao estudo da guitarra

O presente relatório é escrito no âmbito da unidade curricular de Prática de Ensino Supervisionada, pertencendo ao plano curricular do Mestrado em Ensino de Música, na Escola Superior de Artes Aplicadas do Instituto Politécnico de Castelo Branco. A primeira parte aborda a Prática de Ensino Supervisionada, realizada na Academia de Música de Castelo de Paiva, durante o ano letivo 2020/21, onde foi feita uma caracterização do meio envolvente, da escola, dos alunos de Estágio; critérios e planificações anuais de instrumento e classe de conjunto e as planificações e respetivos relatórios de aula. Na segunda parte, é apresentado o trabalho de investigação com o título “A Gravação Audiovisual como ferramenta de apoio ao estudo da Guitarra”. A realização desta investigação teve como objetivo perceber se a utilização da Gravação Audiovisual se pode tornar numa boa ferramenta para o desenvolvimento do processo de aprendizagem ou se não acrescenta nada a este processo de aprendizagem. A investigação-ação foi desenvolvida com quatro alunos e, no final da mesma, foi possível apurar que a utilização da Gravação Audiovisual se tornou benéfica na aprendizagem dos alunos.Abstract : This report is written within the framework of the Supervised Practice curriculum unit, belonging to the curriculum of the Master's degree in Music Teaching, at Escola Superior de Artes Aplicadas do Instituto Politécnico de Castelo Branco. The first part is related to the Supervised Teaching Practice, held at the Academia de Música de Castelo de Paiva, during the school year 2020/21, where a characterization of the environment, the school, the internship students was made; annual instrument and class criteria and planning and the planning and their lesson reports. The second part, research work with the title "A Gravação Audiovisual como ferramenta de aopio ao estudo da Guitarra" is presented. The aim of this research was to understand whether the use of Audiovisual Recording has become a good tool for development of the learning process or whether it adds nothing to this learning process. The action investigation was carried out with four students and at the end of it, it was possible to ascertain that the use of Audiovisual Recording has become beneficial in learning students