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Publications

2017

Measuring Impedance in Congestive Heart Failure

Authors
Silva, R; Cardoso, J; Sousa, F;

Publication
PHEALTH 2017

Abstract
The hospitalization of patients with Heart Failure represents an increasing burden for the healthcare system with more than 23 million worldwide suffering from this disease. In this paper we explore methods to detect fluid retention in the lungs by measuring the thoracic impedance, so that is possible to monitor Heart Failure patients, and physicians can early detect acute episodes. A small and portable device was developed to measure the thoracic impedance of the patient. From the measured thoracic impedance it can estimate the accumulation of fluid in the lungs. This device is a low cost, friendly to use equipment that can be operated by a big range of users: Moreover, it was designed for low power consumption with a rechargeable battery for portable use. The device empowers the patient to monitor his own body fluid at home, and a physician can follow him remotely. This procedure would help to drastically reduce the number of hospitalizations and, consequently, improve the quality of life of people diagnosed with Heart Failure.

2017

Integration of Data Distribution Service and Raspberry Pi

Authors
Garcia Valls, M; Ampuero Calleja, J; Ferreira, LL;

Publication
GREEN, PERVASIVE, AND CLOUD COMPUTING (GPC 2017)

Abstract
Embedded computers such as Raspberry Pi are gaining market as they offer considerable computation power on a flexible platform that can run different operating systems and user level libraries. There are a number of contributions on building middleware for connecting devices based on embedded computers in various ways; however, the temporal behavior of these systems has not been sufficiently covered, despite the fact that this is essential to validate the system design, operation, and timeliness that is needed in domains such as cyber-physical systems (CPS). This paper analyzes the temporal behavior of the connection among embedded computers and servers in the context of time sensitive deployments where some nodes can be virtualized offering mixed criticality execution platforms. We provide a scheme for using the Data Distribution Service standard to connect embedded computers based on Raspberry Pi and servers to analyze the temporal response stability.

2017

Vertical land motion and sea level change in Macaronesia

Authors
Mendes, VB; Barbosa, SM; Romero, I; Madeira, J; da Silveira, AB;

Publication
GEOPHYSICAL JOURNAL INTERNATIONAL

Abstract
This study addresses long-term sea level variability in Macaronesia from a holistic perspective using all available instrumental records in the region, including a dense network of GPS continuous stations, tide gauges and satellite observations. A detailed assessment of vertical movement from GPS time series underlines the influence of the complex volcano-tectonic setting of the Macaronesian islands in local uplift/subsidence. Relative sea level for the region is spatially highly variable, ranging from -1.1 to 5.1 mm yr(-1). Absolute sea level from satellite altimetry exhibits consistent trends in the Macaronesia, with a mean value of 3.0 +/- 0.5 mm yr(-1). Typically, sea level trends from tide gauge records corrected for vertical movement using the estimates from GPS time series are lower than uncorrected estimates. The agreement between satellite altimetry and tide gauge trends corrected for vertical land varies substantially from island to island. Trends derived from the combination of GPS and tide gauge observations differ by less than 1 mm yr(-1) with respect to absolute sea level trends from satellite altimetry for 56 per cent of the stations, despite the heterogeneity in length of both GPS and tide gauge series, and the influence of volcanic-tectonic processes affecting the position of some GPS stations.

2017

Multi-Robot Planning for Perception of Multiple Regions of Interest

Authors
Pereira, T; Mendes Moreira, APG; Veloso, MM;

Publication
ROBOT 2017: Third Iberian Robotics Conference - Volume 1, Seville, Spain, November 22-24, 2017

Abstract
In this paper we address the allocation of perception tasks among a set of multiple robots, for tasks such as inspection, surveillance, or search in structured environments. We consider a set of target regions of interest in a mapped environment that need to be sensed by any of the robots, and the problem is to find paths for the robots that cover all the target regions with minimal cost. We consider not only sensing range when determining paths for the robots to perceive the targets, but also a sensor cost function that can be adapted to each robot’s sensor. Thus the planning has to search for paths with minimal motion and perception cost, instead of the traditional approach where line-of-sight is the only requirement in a motion cost minimization problem. Our contribution is to use planning to determine possible perception positions for every robot, which we cluster and then use as possible waypoints that can be used to construct paths for all the robots. Given the combinatorial characteristics of path determination in this setting, we contribute a construction heuristic to find paths that guarantee full coverage of all the feasible perception target regions, while minimizing the overall cost. We assume robots are heterogeneous regarding their geometric properties, such as size and maximum perception range. We consider simulated scenarios where we show the benefits of our approach, enabling multi-robot path planning for perception of multiple regions of interest. © Springer International Publishing AG 2018.

2017

Making system of systems interoperable - The core components of the arrowhead framework

Authors
Varga, P; Blomstedt, F; Ferreira, LL; Eliasson, J; Johansson, M; Delsing, J; de Soria, IM;

Publication
JOURNAL OF NETWORK AND COMPUTER APPLICATIONS

Abstract
The objective of the Arrowhead Framework is to efficiently support the development, deployment and operation of interconnected, cooperative systems. It is based on the Service Oriented Architecture philosophy. The building elements of the framework are systems that provide and consume services, and cooperate as systems of systems. Some commonly used systems, such as orchestration, authorization or service registry are considered as core. These can be used by any system of systems that follow the guidelines of the Arrowhead Framework. Within the framework, systems - using different information exchange technologies during collaboration - are helped through various approaches. These include the so-called Interoperability Layer, as well as systems and services for translation. Furthermore, one of the main problems of developing such highly interoperable systems is the lack of understanding between various development groups. Adequate development and service documentation methodologies can help to overcome this issue. The design, development and verification methodology for each service, system and system of systems within the Arrowhead Framework supports that these can be implemented, verified, deployed, and run in an interoperable way. This paper presents an overview of the framework together with its core elements - and provides guidelines for the design and deployment of interoperable, Arrowhead-compliant cooperative systems.

2017

Two-Tier Reactive Power and Voltage Control Strategy Based on ARMA Renewable Power Forecasting Models

Authors
Lu, JL; Wang, B; Ren, H; Zhao, DQ; Wang, F; Shafie khah, M; Catalao, JPS;

Publication
ENERGIES

Abstract
To address the static voltage stability issue and suppress the voltage fluctuation caused by the increasing integration of wind farms and solar photovoltaic (PV) power plants, a two-tier reactive power and voltage control strategy based on ARMA power forecasting models for wind and solar plants is proposed in this paper. Firstly, ARMA models are established to forecast the output of wind farms and solar PV plants. Secondly, the discrete equipment is pre-regulated based on the single-step prediction information from ARMA forecasting models according to the optimization result. Thirdly, a multi-objective optimization model is presented and solved by particle swarm optimization (PSO) according to the measured data and the proposed static voltage stability index. Finally, the IEEE14 bus system including a wind farm and solar PV plant is utilized to test the effectiveness of the proposed strategy. The results show that the proposed strategy can suppress voltage fluctuation and improve the static voltage stability under the condition of high penetration of renewables including wind and solar power.

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