Cookies Policy
The website need some cookies and similar means to function. If you permit us, we will use those means to collect data on your visits for aggregated statistics to improve our service. Find out More
Accept Reject
  • Menu
Publications

2009

Context Inference for Mobile Applications in the UPCASE Project

Authors
Santos, AC; Tarrataca, L; Cardoso, JMP; Ferreira, DR; Diniz, PC; Chainho, P;

Publication
MOBILE WIRELESS MIDDLEWARE, OPERATING SYSTEMS, AND APPLICATIONS

Abstract
The growing processing capabilities of mobile devices coupled with portable and wearable sensors have enabled the development of context-aware services tailored to the user environment and its daily activities. The problem of determining the user context at each particular point in time is one of the main challenges in this area. In this paper, we describe the approach pursued in the UPCASE project, which makes use of sensors available in the mobile device as well as sensors externally connected via Bluetooth. We describe the system architecture from raw data acquisition to feature extraction and context inference. As a proof of concept, the inference of contexts is based on a decision tree to learn and identify contexts automatically and dynamically at runtime. Preliminary results suggest that this is a promising approach for context inference in several application scenarios.

2009

Realistic simulation of a Lego Mindstorms NXT based robot

Authors
Goncalves, J; Lima, J; Malheiros, P; Costa, P;

Publication
2009 IEEE CONTROL APPLICATIONS CCA & INTELLIGENT CONTROL (ISIC), VOLS 1-3

Abstract
This paper describes the realistic simulation of a Lego Mindstorms NXT based robot. The presented approach does not replace the training with hardware but is an important complement, since it allows to develop robot software without accessing to the real hardware.

2009

Comparison of two new short-term wind-power forecasting systems

Authors
Ramirez Rosado, IJ; Alfredo Fernandez Jimenez, LA; Monteiro, C; Sousa, J; Bessa, R;

Publication
RENEWABLE ENERGY

Abstract
This paper presents a comparison of two new advanced statistical short-term wind-power forecasting systems developed by two independent research teams. The input variables used in both systems were the same: forecasted meteorological variable values obtained from a numerical weather prediction model: and electric power-generation registers from the SCADA system of the wind farm. Both systems are described in detail and the forecasting results compared, revealing great similarities, although the proposed structures of the two systems are different. The forecast horizon for both systems is 72 h, allowing the use of the forecasted values in electric market operations, as diary and intra-diary power generation bid offers, and in wind-farm maintenance planning.

2009

Using Vehicle-to-Grid to Maximize the Integration of Intermittent Renewable Energy Resources in Islanded Electric Grids

Authors
Pecas Lopes, JAP; Rocha Almeida, PMR; Soares, FJ;

Publication
2009 INTERNATIONAL CONFERENCE ON CLEAN ELECTRICAL POWER (ICCEP 2009), VOLS 1 AND 2

Abstract
This paper presents the results of a dynamic behaviour analysis study developed with the objective of quantifying the amount of wind power that can he safely, integrated in an isolated electricity grid where Electric Vehicles (EVs) are present. The assessment was performed considering two distinct situations: a) when EVs are only, in charging mode and b) when EVs participate in primary frequency, control. The test system, a small island, contains, in addition to wind generation, a small amount of solar PV plants and four conventional diesel generators. Only wind power influence in system's frequency, was assessed since, from a dynamic perspective, this is the renewable resource whose high intermittency level might be more harmful for the electric system operation. Sudden wind variations were simulated and, for both situations, a) and b), the amount of Intermittent Renewable Energy Sources was maximized, keeping always the grid frequency, within the limits defined by: the power quality standards.

2009

Modal Interferometer Based on ARROW Fiber for Strain and Temperature Measurement

Authors
Aref, SH; Frazao, O; Caldas, P; Ferreira, LA; Araujo, FM; Santos, JL; Latifi, H; Foy, P; Hawkins, T; Ballato, J; Her, T; Farahi, F;

Publication
IEEE PHOTONICS TECHNOLOGY LETTERS

Abstract
In this letter, interferometric sensors based on antiresonance reflecting optical waveguide (ARROW) fibers were developed, and used to sense strain and temperature. Two types of solid-ore ARROW fibers were considered and signal demodulation was achieved by using the white light interferometric technique. The ARROW fibers have two rings of high index rods arranged in a hexagonal structure with a lattice constant of 6 m. The different sizes of the rods cause different measurand sensitivities for the two fibers. Resolutions of +/- 1.1 mu epsilon and +/- 0.07 degrees C were achieved for strain and temperature, respectively.

2009

Linux software and Bluetooth: a formula to improve accessibility by using Interactive Voice Response systems

Authors
Almeida, NT; Ribeiro, E;

Publication
DSAI 2009: PROCEEDINGS OF THE 2ND INTERNATIONAL CONFERENCE ON SOFTWARE DEVELOPMENT FOR ENHANCING ACCESSIBILITY AND FIGHTING INFO-EXCLUSION

Abstract
When accessing and interacting with regular electronic devices or informatics systems, users frequently depend on the sight sense because the information is, consistently, presented in a visual format, despite the feasibility to use additional formats, such as audio. It also happens that the access to the information systems is triggered by the action of the users, hence requiring an awareness of the surrounding environment. These two facts lead to an exclusion of a considerable number of citizens, such as the visually impaired ones, from a fair access to the so-called Information Society. The development of automatic user-aware Interactive Voice Response (IVR) systems can be an interesting solution to this issue, particularly, if the communications are done in a private manner and a low-cost implementation is achieved. In a reply to this challenge, it was formulated a pervasive user detection and communication concept, based on Bluetooth technology and Linux software modules, allowing improved interaction between the personal area information systems and the mobile user devices. To demonstrate the validity of the concept, it was developed a personal area IVR system, based on Linux, being the interaction with the users made by means of the Bluetooth technology.

  • 3892
  • 4503