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Publications

2016

How to Correctly Evaluate an Automatic Bioacoustics Classification Method

Authors
Colonna, JG; Gama, J; Nakamura, EF;

Publication
ADVANCES IN ARTIFICIAL INTELLIGENCE, CAEPIA 2016

Abstract
In this work, we introduce a more appropriate (or alternative) approach to evaluate the performance and the generalization capabilities of a framework for automatic anuran call recognition. We show that, by using the common k-folds Cross-Validation (k-CV) procedure to evaluate the expected error in a syllable-based recognition system the recognition accuracy is overestimated. To overcome this problem, and to provide a fair evaluation, we propose a new CV procedure in which the specimen information is considered during the split step of the k-CV. Therefore, we performed a k-CV by specimens (or individuals) showing that the accuracy of the system decrease considerably. By introducing the specimen information, we are able to answer a more fundamental question: Given a set of syllables that belongs to a specific group of individuals, can we recognize new specimens of the same species? In this article, we go deeper into the reviews and the experimental evaluations to answer this question.

2016

Long-term changes in the seasonality of Baltic sea level

Authors
Barbosa, SM; Donner, RV;

Publication
TELLUS SERIES A-DYNAMIC METEOROLOGY AND OCEANOGRAPHY

Abstract
The seasonal cycle accounts for about 40 % of the total sea level variability in the Baltic Sea. In a climate change context, changes are expected to occur, not only in mean levels but also in the seasonal characteristics of sea level. The present study addresses the quantification of changes in the seasonal cycle of sea level from a set of century-long tide gauge records in the Baltic Sea. In order to obtain robust estimates of the changes in amplitude and phase of the seasonal cycle, we apply different methods, including continuous wavelet filtering, multi-resolution decomposition based on the maximal overlap discrete wavelet transform, auto-regressive-based decomposition, singular spectrum analysis and empirical mode decomposition. The results show that all methods generally trace a similar long-term variability of the annual cycle amplitudes, and we focus on discrete wavelet analysis as the natural counterpart of classical moving Fourier analysis. In contrast to previous studies suggesting the existence of long-term changes in the seasonal cycle, in particular an increase of the annual amplitude, we find alternating periods of high and low amplitudes without any clear indication of systematic long-term trends. The derived seasonal patterns are spatially coherent, discriminating the stations in the Baltic entrance from the remaining stations in the Baltic basin, for which zonal wind accounts for typically more than 40 % of the variations in amplitude.

2016

Machine Learning in Software Defined Networks: Data Collection and Traffic Classification

Authors
Amaral, P; Dinis, J; Pinto, P; Bernardo, L; Tavares, J; Mamede, HS;

Publication
2016 IEEE 24TH INTERNATIONAL CONFERENCE ON NETWORK PROTOCOLS (ICNP)

Abstract
Software Defined Networks (SDNs) provides a separation between the control plane and the forwarding plane of networks. The software implementation of the control plane and the built in data collection mechanisms of the OpenFlow protocol promise to be excellent tools to implement Machine Learning (ML) network control applications. A first step in that direction is to understand the type of data that can be collected in SDNs and how information can be learned from that data. In this work we describe a simple architecture deployed in an enterprise network that gathers traffic data using the OpenFlow protocol. We present the data-sets that can be obtained and show how several ML techniques can be applied to it for traffic classification. The results indicate that high accuracy classification can be obtained with the data-sets using supervised learning.

2016

Adoption of auditability as a proposal to identify false information on social networks [Adoção da auditabilidade como proposta para identificar informações falsas em redes sociais]

Authors
Pinheiro, A; Cappelli, C; MacIel, C;

Publication
CEUR Workshop Proceedings

Abstract
The lack of mechanisms made to check reliability of information on social networks is evidenced by the spread of misinformation and rumors in this kind of system. Given this scenario, the provision of tools to assist users with information auditability on social networks needs an emergencial approach. This article describes a catalog, followed by a guide of features that provide auditability on social networks. The guide contains guidelines for development of funcionalities in order to promote the adoption of auditability and enable users to identify false information and validate content on social networks. © 2016 for this paper by its authors.

2016

Accessibility Not on Demand An Impaired Situation

Authors
de Sousa e Silva, JDE; Goncalves, R; Pereira, A;

Publication
ICSOFT-EA: PROCEEDINGS OF THE 11TH INTERNATIONAL JOINT CONFERENCE ON SOFTWARE TECHNOLOGIES - VOL. 1

Abstract
Digital accessibility is recognized as a fundamental tool for an egalitarian society. Nevertheless, software accessibility is an under addressed topic in the discipline of software engineering and the academy in general. As a result, its development and implementation is compromised. This problem is depicted here with the help of some experiments that shows the poor attention which is dedicated to this topic. Some hypotheses that try to explain this problem are formulated, and some possible solutions are debated. As a conclusion, some insights are given and a new possible researched avenue is presented.

2016

The problem with embedded CRDT counters and a solution

Authors
Baquero, C; Almeida, PS; Lerche, C;

Publication
PROCEEDINGS OF THE 2ND WORKSHOP ON THE PRINCIPLES AND PRACTICE OF CONSISTENCY FOR DISTRIBUTED DATA, PAPOC 2016

Abstract
Conflict-free Replicated Data Types (CRDTs) can simplify the design of deterministic eventual consistency. Considering the several CRDTs that have been deployed in production systems, counters are among the first. Counters are apparently simple, with a straightforward inc/dec/read API, but can require complex implementations and several variants have been specified and coded. Unlike sets and registers, that can be adapted to operate inside maps, current counter approaches exhibit anomalies when embedded in maps. Here, we illustrate the anomaly and propose a solution, based on a new counter model and implementation.

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