2008
Authors
Frazao, O; Silva, SO; Baptista, JM; Santos, JL; Statkiewicz Barabach, G; Urbanczyk, W; Wojcik, J;
Publication
APPLIED OPTICS
Abstract
A Sagnac interferometer with a section of a polarization maintaining side-hole fiber for multiparameter measurement is proposed. The sensor was experimentally demonstrated to be sensitive to torsion, temperature, and longitudinal strain, simultaneously The birefringence in the investigated side-hole fiber is induced simultaneously by the elliptical shape of a germanium-doped core and by field overlap with the air holes surrounding the core. The latter effect is purely geometrical and causes high chromatic dispersion of the group birefringence in the long wavelength range, which results in a different period of spectral interference fringes. A different wavelength response is obtained for each interference fringe peak when the fiber is subjected to torsion, temperature, or longitudinal strain. A matrix equation for simultaneous measurement of the three parameters-torsion, temperature, and longitudinal strain-is also proposed. (C) 2008 Optical Society of America
2008
Authors
Alves, JC; Ramos, TM; Cruz, NA;
Publication
OGAI Journal (Oesterreichische Gesellschaft fuer Artificial Intelligence)
Abstract
This paper presents the computing infrastructure used in an autonomous unmanned small-scale sailboat. The system is based on a FPGA and includes custom designed interfaces for the various sensors and actuators used in the sailboat. The central processing unit is a 32-bit 50 MHz RISC microprocessor implemented as a soft IP core in the FPGA. The computing system runs uClinux, a simplified version of the popular Linux operating system. The usage of a reconfigurable platform enables a quick reconfiguration of the logic circuit implemented in the FPGA, facilitating the development stage and allowing a dynamic switch among different implementations, according to the navigation requirements and environmental conditions.
2008
Authors
Barbosa, SM;
Publication
HIMALAYAN GEOLOGY
Abstract
2008
Authors
Teixeira, J; Vinhas, V; Oliveira, E; Reis, LP;
Publication
Proceedings - 2008 IEEE/WIC/ACM International Conference on Web Intelligence and Intelligent Agent Technology - Workshops, WI-IAT Workshops 2008
Abstract
Several knowledge areas such as psychology, medicine and computer science have been devoting serious efforts regarding emotional state definition, identification and assessment. This project consists in an automatic emotion assessment tool based on biometric data acquisition supported by low-budget biometric devices as a electroencephalograph and a galvanic skin response. The classification is grounded on data analysis and processing of standard emotional induction methods. The numerous conducted experimental sessions, alongside with the developed support tools, allowed the extraction of conclusions such as the capability of effectively performing automatic classification of the subject's predominant emotional state. The developed tool's success rate, validated against self assessment interviews, was approximately 75%. It was also experimentally concluded that female subjects are emotionally more active and easily induced than males. © 2008 IEEE.
2008
Authors
Wang, SL; Barbosa, LS; Oliveira, JN;
Publication
TASE 2008: SECOND IFIP/IEEE INTERNATIONAL SYMPOSIUM ON THEORETICAL ASPECTS OF SOFTWARE ENGINEERING, PROCEEDINGS
Abstract
Confined separation logic is a new extension to separation logic designed to deal with problems involving dangling references within shared mutable structures. In particular it allows for reasoning about confinement in object-oriented programs. In this paper, we discuss the semantics of such an extension by defining a relational model for the overall logic, parametric on the shapes of both the store and the heap. This model provides a simple and elegant interpretation of the new confinement connectives and helps in seeking for duals. A number of properties of this logic are proved calculationally.
2008
Authors
Frazao, O; Correia, C; Baptista, JM; Marques, MB; Santos, JL;
Publication
OPTICS COMMUNICATIONS
Abstract
This work presents two distinct configurations based on phase-wavelength conversion using a ring fibre laser with two different long period gratings interferometer topologies. The sensors are interrogated by analysing the wavelength change of the emission laser, which is directly dependent on the interferometer phase change. The first configuration integrates a Mach-Zehnder interferometer, which is based on a pair of long period gratings and is used as sensing head for bending radius and longitudinal strain measurement. The second configuration, comprehends a Michelson interferometer, which is based on a single LPG and a fibre end mirror and is used as a liquid level sensor or as an optical refractometer.
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