Metrics for Association Rule Clustering Assessment

Issues related to association mining have received attention, especially the ones aiming to discover and facilitate the search for interesting patterns. A promising approach, in this context, is the application of clustering in the pre-processing step. In this paper, eleven metrics are proposed to provide an assessment procedure in order to support the evaluation of this kind of approach. To propose the metrics, a subjective evaluation was done. The metrics are important since they provide criteria to: (a) analyze the methodologies, (b) identify their positive and negative aspects, (c) carry out comparisons among them and, therefore, (d) help the users to select the most suitable solution for their problems. Besides, the metrics do the users think about aspects related to the problems and provide a flexible way to solve them. Some experiments were done in order to present how the metrics can be used and their usefulness.

Maximal power output during incremental cycling test is dependent on the curvature constant of the power-time relationship

The aim of this study was to investigate whether the maximal power output (Pmax) during an incremental test was dependent on the curvature constant (W') of the power-time relationship. Thirty healthy male subjects (maximal oxygen uptake = 3.58 ± 0.40 L·min(-1)) performed a ramp incremental cycling test to determine the maximal oxygen uptake and Pmax, and 4 constant work rate tests to exhaustion to estimate 2 parameters from the modeling of the power-time relationship (i.e., critical power (CP) and W'). Afterwards, the participants were ranked according to their magnitude of W'. The median third was excluded to form a high W' group (HIGH, n = 10), and a low W' group (LOW, n = 10). Maximal oxygen uptake (3.84 ± 0.50 vs. 3.49 ± 0.37 L·min(-1)) and CP (213 ± 22 vs. 200 ± 29 W) were not significantly different between HIGH and LOW, respectively. However, Pmax was significantly greater for the HIGH (337 ± 23 W) than for the LOW (299 ± 40 W). Thus, in physically active individuals with similar aerobic parameters, W' influences the Pmax during incremental testing.

Práticas de integração interfuncional em projetos de inovação radical e incremental: estudo de casos em empresas industriais de médio e grande porte

Pós-graduação em Engenharia de Produção - FEB

A comparison about evolutionary algorithms for optimum-path forest clustering optimization

In this paper we deal with the problem of boosting the Optimum-Path Forest (OPF) clustering approach using evolutionary-based optimization techniques. As the OPF classifier performs an exhaustive search to find out the size of sample's neighborhood that allows it to reach the minimum graph cut as a quality measure, we compared several optimization techniques that can obtain close graph cut values to the ones obtained by brute force. Experiments in two public datasets in the context of unsupervised network intrusion detection have showed the evolutionary optimization techniques can find suitable values for the neighborhood faster than the exhaustive search. Additionally, we have showed that it is not necessary to employ many agents for such task, since the neighborhood size is defined by discrete values, with constrain the set of possible solution to a few ones.

Reproducibility of heart rate and rating of perceived exertion values obtained from different incremental treadmill tests

Objective The present study aimed to examine the reproducibility of heart rate (HR) and rating of perceived exertion (RPE) values obtained during different incremental treadmill tests. Equipment and methods Twenty male, recreational, endurance-trained runners (10-km running pace: 10–15 km·h−1) performed, in a counterbalanced order, three continuous incremental exercise tests with different speed increments (0.5 km·h−1, 1 km·h−1 and 2 km·h−1). Thereafter, each participant performed the three tests again, maintaining the same order as before. The reproducibility of the HR and RPE values were analyzed for all protocols during submaximal intensities (8, 10, 12, and 14 km·h−1). In addition, it was examined the reproducibility of maximal HR (HRmax) and peak RPE (RPEpeak). Results The variability of both the HR and RPE values showed a tendency to decrease over the stages during the incremental test and was not or slightly influenced by the incremental test design. The HR at 14 km·h−1 and HRmax presented the highest reproducibility (CV < 2%). In contrast, the submaximal RPE values showed higher variability indices (i.e., CV > 5.0%). In conclusion, the HR values were highly reproducible during the stages of the incremental test, in contrast to the RPE values that presented limited reproducibility.