The rapid spread of wearable technologies has motivated the collection of a variety of signals, such as pulse rate, electrocardiogram (ECG), electroencephalogram (EEG), and others. As those devices are used to do so many tasks and store a significant amount of personal data, the concern of how our data can be exposed starts to gain attention as the wearable devices can become an attack vector or a security breach. In this context, biometric also has expanded its use to meet new security requirements of authentication demanded by online applications, and it has been used in identification systems by a large number of people. Existing works on ECG for user authentication do not consider a population size close to a real application. Finding real data that has a big number of people ECG’s data is a challenge. This work investigates a set of steps that can improve the results when working with a higher number of target classes in a biometric identification scenario. These steps, such as increasing the number of examples, removing outliers, and including a few additional features, are proven to increase the performance in a large data set. We propose a data improvement model for ECG biometric identification (user identification based on electrocardiogram—DETECT), which improves the performance of the biometric system considering a greater number of subjects, which is closer to a security system in the real world. The DETECT model increases precision from 78% to 92% within 1500 subjects, and from 90% to 95% within 100 subjects. Moreover, good False Rejection Rate (i.e., 0.064003) and False Acceptance Rate (i.e., 0.000033) were demonstrated. We designed our proposed method over PhysioNet Computing in Cardiology 2018 database.

Dense Internet of Things (DIoT) is fazed by message loss, congestion, and energy consumption, due to a large number of connected devices. One of the main challenges in DIoT environments is to achieve self-adaptable communication without human intervention, where the system is able to dynamically manage its own settings to mitigate common problems. Seeking to promote self-adaptability in DIoT, this paper presents the Autonomic management of GRoup communication for intErnEt of thiNgs applications (AGREEN). It is an autonomous solution for IoT platforms that configures the communication settings to ensure the dynamic control of IoT devices considering a comprehensive set of aspects, such as traffic loss, sensing relevance, amount of energy harvested, and the number of monitoring nodes with renewable and nonrenewable energy. Extensive evaluation results show that AGREEN is able to autonomously change the number of nodes in the monitoring group and to improve system performance in terms of message loss, energy consumption, and communication interval compared to standard protocols designed for IoT.