BIOMECHANICS OF THE PENALTY STROKE IN ROLLER HOCKEY

This paper describes a preliminary study on the biomechanics of the shot in roller hockey. This is a Portuguese sport having a most extensive prize list, where Portugal has been 15 times world champion, 20 European champions in senior male competition and won three world championships in senior female. Despite this impressive collection of titles, hockey continues to be the lesser studied sport, concretely regarding studies on biomechanics. The influence of sports equipment in the athlete’s performance and a detailed analysis of the main technical gestures had not motivated yet the researchers for detailed studies to enable their optimization. The purpose of this study was to characterize the mechanical properties of the stick (Aleu) and its influence on the shot power

Usando Redes Aleatorias na Analise de Mobilidade

National audienceThe constant advancement of information systems has allowed more data to be generated and stored from the most diverse situations. It is fascinating that, behind these records, we see the reflection of the environment itself, since every record represents a decision made by some entity. In this work, we modeled real-world scenarios of mobility from using temporal complex networks. The analysis assumes that these systems are composed of entities able to interact in a rational manner, reflecting their interests and activity dynamic. In this direction, we propose a technique for analyzing mobility scenarios from random graphs. This technique examines how the real system would evolve if the agents' decisions were random, and from there, you can check, for example, which edges are random and which are derived from social relationships, such as friendship or professional.O avanco constante de sistemas de informacao tempermitido que mais dados sejam gerados e armazenados a partir das mais diversas situacoes. E fascinante que, por tras de cada registro, seja possıvel ver o reflexo do ambiente em si, ou seja, alguma decisao tomada por alguma entidade. Neste trabalho, sao estudados cenarios reais de mobilidade a partir de uma modelagem usando redes complexas temporais. A analise parte do pressuposto que esses sistemas sao compostos de entidades capazes de interagir entre si de uma maneira racional, refletindo seus interesses e dinamica de atividade. Nessa direcao, e proposta uma tecnica para analisar cenarios de mobilidade a partir de grafos aleatorios. Essa tecnica verifica como o sistema real evoluiria caso as decisoes dos seus agentes fossem aleat'orias e, a partir dela, pode-se verificar, por exemplo, quais arestas s˜ao aleat'orias e quais s˜ao provenientes de relac¸ ˜oes sociais, tais como relac¸ ˜oes de amizade ou profissionais

RECAST: Telling Apart Social and Random Relationships in Dynamic Networks

International audienceIn this paper, we argue that the ability to accurately spot random and social relationships in dynamic networks is essential to net- work applications that rely on human routines, such as, e.g., op- portunistic routing. We thus propose a strategy to analyze users' interactions in mobile networks where users act according to their interests and activity dynamics. Our strategy, named Random rElationship ClASsifier sTrategy (RECAST), allows classifying users' wireless interactions, separating random interactions from differ- ent kinds of social ties. To that end, RECAST observes how the real system differs from an equivalent one where entities' decisions are completely random. We evaluate the effectiveness of the RECAST classification on real-world user contact datasets collected in diverse networking contexts. Our analysis unveils significant dif- ferences among the dynamics of users' wireless interactions in the datasets, which we leverage to unveil the impact of social ties on opportunistic routing

Participatory Sensor Networks as Sensing Layers

International audienceParticipatory sensor networks (PSNs) regards smartphone users as consumers as well as active producers of data. A sensing layer represents a type of data, coming from a given source of data, such as web services, traditional wireless sensor networks, and PSNs. In this work, we show the usefulness and potential of having sensing layers in PSNs. We also show how we can formalize the concept of sensing layers in participatory sensor networks. Furthermore, we demonstrate how to derive and create new applications and services that are not promptly available from different sensing layers, opening up very interesting research opportunities

Traffic Condition Is More Than Colored Lines on a Map: Characterization of Waze Alerts

International audienceParticipatory sensor network (PSN) enables the understanding of city dynamics and the urban behavioral patterns of their inhabitants. In this work, we focus our analysis on a specific PSN, derived from Waze, for sensing traffic con-ditions. Our objective is to characterize the properties of this PSN, its broad and global spatial coverage as well as its limitations. We also bring discussions on dif-ferent opportunities for application design using this network. We claim that the PSN derived from Waze has the potential to help us in the better understanding of traffic problem reasons. Besides that, it could be useful for improving algorithms used in navigation services: (1) by exploiting the provided real-time traffic in-formation or (2) by helping in the identification of valuable pieces of information that are hard to detect with traditional sensors, such as car accidents and potholes