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Publicações

2017

Fast physical ray-tracing method for gravitational lensing using heterogeneous supercomputing in GPGPU

Autores
Costa, JC; Gomes, M; Alves, RA; Silva, NA; Guerreiro, A;

Publicação
THIRD INTERNATIONAL CONFERENCE ON APPLICATIONS OF OPTICS AND PHOTONICS

Abstract
In this work we address the development of a fast solver of the ray-tracing equations based on heterogeneous supercomputing using PyOpenCL. We apply this solver to the study of gravitational lensing and light propagation in optical systems.

2017

Skill-based anytime agent architecture for logistics and manipulation tasks: EuRoC Challenge 2, Stage II - Realistic Labs: Benchmarking

Autores
Amaral, F; Pedrosa, E; Lim, GH; Shafii, N; Pereira, A; Azevedo, JL; Cunha, B; Reis, LP; Badini, S; Lau, N;

Publicação
2017 IEEE International Conference on Autonomous Robot Systems and Competitions, ICARSC 2017, Coimbra, Portugal, April 26-28, 2017

Abstract
Nowadays, the increase of robotic technology application to industry scenarios is notorious. Proposals for new effective solutions are in continuous development once industry needs a constantly improvement in time as well as in production quality and efficiency. The EuRoC research project proposes a scientific competition in which research and industry manufacturers joint teams are encouraged to develop and test solutions that can solve several issues as well as be useful in manufacturing improvement. This paper presents the TIMAIRIS architecture and approach used in the Challenge 2 - Stage II - Benchmarking phase, namely regarding the perception, manipulation and planning strategy that was applied to achieve the tasks objectives. The used approach proved to be quite robust and efficient, which allowed us to rank first in the Benchmarking phase. © 2017 IEEE.

2017

PRECIOUS! Out-of-reach selection using iterative refinement in VR

Autores
Mendes, D; Medeiros, D; Cordeiro, E; Sousa, M; Ferreira, A; Jorge, JA;

Publicação
2017 IEEE Symposium on 3D User Interfaces, 3DUI 2017, Los Angeles, CA, USA, March 18-19, 2017

Abstract
Selecting objects outside user's arm-reach in Virtual Reality still poses significant challenges. Techniques proposed to overcome such limitations often follow arm-extension metaphors or favor the use of selection volumes combined with ray-casting. Nonetheless, these approaches work for room sized and sparse environments, and they do not scale to larger scenarios with many objects. We introduce PRECIOUS, a novel mid-air technique for selecting out-of-reach objects. It employs an iterative progressive refinement, using cone-casting to select multiple objects and moving users closer to them in each step, allowing accurate selections. A user evaluation showed that PRECIOUS compares favorably against existing approaches, being the most versatile. © 2017 IEEE.

2017

Combining discriminative spatiotemporal features for daily life activity recognition using wearable motion sensing suit

Autores
Vital, JPM; Faria, DR; Dias, G; Couceiro, MS; Coutinho, F; Ferreira, NMF;

Publicação
PATTERN ANALYSIS AND APPLICATIONS

Abstract
Motion sensing plays an important role in the study of human movements, motivated by a wide range of applications in different fields, such as sports, health care, daily activity, action recognition for surveillance, assisted living and the entertainment industry. In this paper, we describe how to classify a set of human movements comprising daily activities using a wearable motion capture suit, denoted as FatoXtract. A probabilistic integration of different classifiers recently proposed is employed herein, considering several spatiotemporal features, in order to classify daily activities. The classification model relies on the computed confidence belief from base classifiers, combining multiple likelihoods from three different classifiers, namely Na < ve Bayes, artificial neural networks and support vector machines, into a single form, by assigning weights from an uncertainty measure to counterbalance the posterior probability. In order to attain an improved performance on the overall classification accuracy, multiple features in time domain (e.g., velocity) and frequency domain (e.g., fast Fourier transform), combined with geometrical features (joint rotations), were considered. A dataset from five daily activities performed by six participants was acquired using FatoXtract. The dataset provided in this work was designed to be extremely challenging since there are high intra-class variations, the duration of the action clips varies dramatically, and some of the actions are quite similar (e.g., brushing teeth and waving, or walking and step). Reported results, in terms of both precision and recall, remained around 85 %, showing that the proposed framework is able to successfully classify different human activities.

2017

Toward a Token-Based Approach to Concern Detection in MATLAB Sources

Autores
Monteiro, MP; Marques, NC; Silva, B; Palma, B; Cardoso, J;

Publicação
PROGRESS IN ARTIFICIAL INTELLIGENCE (EPIA 2017)

Abstract
Matrix and data manipulation programming languages are an essential tool for data analysts. However, these languages are often unstructured and lack modularity mechanisms. This paper presents a business intelligence approach for studying the manifestations of lack of modularity support in that kind of languages. The study is focused on MATLAB as a well established representative of those languages. We present a technique for the automatic detection and quantification of concerns in MATLAB, as well as their exploration in a code base. Ubiquitous Self Organizing Map (UbiSOM) is used based on direct usage of indicators representing different sets of tokens in the code. UbiSOM is quite effective to detect patterns of co-occurrence between multiple concerns. To illustrate, a repository comprising over 35, 000 MATLAB files is analyzed using the technique and relevant conclusions are drawn.

2017

Supporting Accessibility in Higher Education Information Systems: A 2016 Update

Autores
Reis, A; Martins, P; Borges, J; Sousa, A; Rocha, T; Barroso, J;

Publicação
UNIVERSAL ACCESS IN HUMAN-COMPUTER INTERACTION: DESIGN AND DEVELOPMENT APPROACHES AND METHODS, PT I

Abstract
Higher Education Institutions (HEIs) have come a long way on the usage of Information Systems (IS) at the several phases of the execution of their business plan. These organizations are very peculiar in the sense that most of the IS technologies have been developed as a consequence of the research work of the HEIs, positioning them as creators and as consumers of IS technologies. In fact, a considerable part of the IS products, currently available for the education sector, was initially created in a HEI as an in-house development. For these reason, the adoption of IS technologies by HEIs has followed two distinct paths: the in-house creation, previously described; and a current market adoption, similarly to most other companies IS adoption. Up to 2013 the IS applications for HEIs was mostly provided as web applications running on the HEI local datacenters and devoted to some specific phases of the HEI business plan. Currently, in 2016, this scenario has evolved in two ways: (i) to a wider range of type of applications, including: the old type of web application; new mobile applications; and new web application, running on the cloud and used as a service, (ii) to a more extended support coverage regarding the HEI business model phases, i.e., there are more IS applications supporting more aspects of the HEIs’ activities. In 2013, it was published a study regarding the accessibility support in HEI IS applications and related user practices. Due to the advances in IS technologies and their adoption by HEIs, it is now time to update this perspective on accessibility and HEIs IS, in order to assess how the progresses on IS applications used in HEIs have dealt with the accessibility concerns. The study updates the IS accessibility features as well as the new systems and new types of systems currently in use. © Springer International Publishing AG 2017.

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