2018
Autores
Pereira, FSF; Gama, J; de Amo, S; Oliveira, GMB;
Publicação
MACHINE LEARNING
Abstract
The preferences adopted by individuals are constantly modified as these are driven by new experiences, natural life evolution and, mainly, influence from friends. Studying these temporal dynamics of user preferences has become increasingly important for personalization tasks in information retrieval and recommendation systems domains. However, existing models are too constrained for capturing the complexity of the underlying phenomenon. Online social networks contain rich information about social interactions and relations. Thus, these become an essential source of knowledge for the understanding of user preferences evolution. In this work, we investigate the interplay between user preferences and social networks over time. First, we propose a temporal preference model able to detect preference change events of a given user. Following this, we use temporal networks concepts to analyze the evolution of social relationships and propose strategies to detect changes in the network structure based on node centrality. Finally, we look for a correlation between preference change events and node centrality change events over Twitter and Jam social music datasets. Our findings show that there is a strong correlation between both change events, specially when modeling social interactions by means of a temporal network.
2018
Autores
Goncalves, F; Pinto, MMGdA; Xavier, A;
Publicação
Advances in Business Information Systems and Analytics - Handbook of Research on Expanding Business Opportunities With Information Systems and Analytics
Abstract
2018
Autores
Ferreira, C; Reis, LP; Santos, CP;
Publicação
Human-Centric Robotics- Proceedings of the 20th International Conference on Climbing and Walking Robots and the Support Technologies for Mobile Machines, CLAWAR 2017
Abstract
Each year thousands of people suffer from lower limb amputation, mainly due to three causes: wars, accidents and vascular diseases. The development of lower limb prosthesis is crucial to restore people’s mobility, improving the quality of life of millions of people. This contribution presents a gait events detector algorithm capable of detecting all the events of the human walking. Results show the correct transition between phases during several gait cycles for a human model walking in flat terrain. © 2018 by World Scientific Publishing Co. Pte. Ltd.
2018
Autores
Lehtonen, J; Correia, CM; Helin, T;
Publicação
ADAPTIVE OPTICS SYSTEMS VI
Abstract
SLODAR (SLOpe Detection And Ranging) methods recover the atmospheric turbulence profile from cross-correlations of wavefront sensor (WFS) measurements, based on known turbulence models. Our work grows out of several experiments showing that turbulence statistics can deviate significantly from the classical Kolmogorov/ von Kármán models, especially close to the ground. We present a novel SLODAR-type method which simultaneously recovers both the turbulence profile in the atmosphere and the turbulence statistics at the ground layer - namely the slope of the spatial frequency power law. We consider its application to outer scale (L0)- reconstruction and investigate the limits of the joint estimation of such parameters.
2018
Autores
Rocio, Vitor; Marcos, Adérito;
Publicação
InforAberta 2018 - VIII Jornadas de Informática da Universidade Aberta
Abstract
2018
Autores
Bessa, RJ; Rua, D; Abreu, C; Machado, P; Andrade, JR; Pinto, R; Gonçalves, C; Reis, M;
Publicação
E-ENERGY'18: PROCEEDINGS OF THE 9TH ACM INTERNATIONAL CONFERENCE ON FUTURE ENERGY SYSTEMS
Abstract
Smart grids technologies are enablers of new business models for domestic consumers with local flexibility (generation, loads, storage) and where access to data is a key requirement in the value stream. However, legislation on personal data privacy and protection imposes the need to develop local models for flexibility modeling and forecasting and exchange models instead of personal data. This paper describes the functional architecture of an home energy management system (HEMS) and its optimization functions. A set of data-driven models, embedded in the HEMS, are discussed for improving renewable energy forecasting skill and modeling multi-period flexibility of distributed energy resources.
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