Antonio Espirito-Santo

A comparison between FFT and MCT for period measurement with an ARM microcontroller

A comparison between two different algorithms to measure the period of a signal is performed on this work. One of the algorithms is based on the Fast Fourier Transformation (FFT) measurement procedure, whereas the other is based on the Segmentation and Labeling algorithm (MCT). Both algorithms have been prepared for implementation in a microcontroller with ARM architecture. The measurement operation of each one of the algorithms is described in detail. Experimental results are reported, with the purpose of demonstrating both performance and output format for signal analysis.

Micro-generation with solar energy: Power qualtity and impact on a rural low-voltage grid

In recent years the grid connected photovoltaic (PV) micro-generation facilities in individual homes has increased due to the adopted governmental policies and the industry attention. The power feed-in of PV generation in rural low-voltage grid can influence the power quality and the facility operation and reliability. This paper presents the results of a power quality analysis of a real PV generation facility connected to a rural low-voltage grid. The voltage fluctuations and the voltage harmonic content are observed and a statistical analysis and discussion are performed. The main achievements of the work are the statement of the disturbances imposed to the grid and its consequences to the technical and economic viability of the PV system.

Development of a low power wireless network to support elderly people based on eZ430-Chronos and SimpliciTI

The welfare of elderly people living alone or in rest homes can be significantly improved with the introduction of technological solutions. However, before start the development of a new commercial product, new ideas and concepts must be quickly validated. The existence of a platform to enable the rapid verification of a solution will be an asset to support the development of a commercial product. The eZ430-Chronos together with the SimpliciTI were modified to build a wireless network that works as a test bench for new products and concepts. After laboratorial validation, an experimental pilot was installed in a rest home, contributing this way to gather fundamental conclusions to be used in the development of new commercial solutions.

Low-power smart sensing in energy and water systems integration

The water energy nexus is a multidisciplinary topic that requires the interaction of different areas of knowledge, with direct impact on the economy, society and ecosystems. Smart sensing concept allows us to develop new ways of monitoring and, consequently, contribute to simultaneously optimize the efficiency of energy and water processes. The integration of energy and water management systems requires the coverage of a wide geographic area. Therefore, the interconnection of smart sensors, over a wireless network, is a requirement that can be assured with the adoption of standards such as the ISO/IEC/IEEE21451. Smart sensors operation and effectiveness depends on the availability of energy. Harvesting energy in water systems allows to power smart sensors avoiding batteries. Microbial fuel cells allow the conversion of organic material found in wastewater into electrical energy. Also, the kinetic energy of induced vibrations in water distribution pipelines can be converted into electrical energy.

Wireless indoor low power tracking system for elderly people assistance in an urban environment

Smart cities and smart homes are driving economic growth and improving the quality of peoples life by enabling local development and harnessing technologies, especially the ones leading to smart outcomes and connectivity. Application of smart solutions will enable human living environments to use technology, information and data to improve infrastructures and services in the behalf of human beings. The welfare of elderly people living alone, at their homes, or, in rest houses, can significantly be improved with the introduction of these smart solutions. Wireless indoor tracking of elderly people is an important feature together with the DLMS/COSEM protocol. Above all using low power devices to assist and monitoring them. The paper highlights implementation in the real world, proposing a method that can be suited in a large range of cases thanks to the scene analysis. An indoor scalable infrastructure allows the tracking method to be implemented incrementally with different performances, where optimal accuracy comes from an adaptable threshold. The method has been tested in different environments using both simulations and direct measurements. Result from the proposed method are compared with the KNN method.

Algorithmic development for power quality monitoring by a network of wireless sensors

Human activity is more than ever dependent on electronic systems. These devices are fed through the electrical grid, which in turn supplies multiple devices simultaneously. The normal operation of an equipment can produce quality events in the power bus that can lead others to fail. This justifies the need for a wireless network of sensors (WSN) spread through the electrical installation. In addition, a wireless solution results in easiness of installation and maintenance. The main task of a WSN will be to monitor in real time the occurrence of power quality events. These goals will demand the development of efficient computational algorithms to detect and report these quality events through the network. In this paper two different solutions are described and compared. In a first approach the wavelet transformation is used for event detection. This solution is afterwards compared with a less computational demanding algorithm based on segmentation and labelling which also compacts the information to be transmitted.