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Publications

2007

Understanding dynamic agent's reasoning

Authors
Lau, N; Reis, LP; Certo, J;

Publication
PROGRESS IN ARTIFICIAL INTELLIGENCE, PROCEEDINGS

Abstract
Heterogeneous agents that execute in dynamic, uncertain, partially cooperative, partially adversely environments have to take their decisions rapidly with an incomplete knowledge of actual environment conditions. This paper discusses different level of abstractions in agent's development for this type of domain, explains the principles of offline debugging and employs these principles in robotic agent's teams through the use of a new visual debugging tool. We argue that during the development of such complex agents, understanding agent reasoning is of crucial importance to the developer and that such understanding can only be done, in most of the cases, using an offline analysis of the agent's decisions. In order for the developer to rapidly perceive agent's reasoning we advocate visual debugging of the agent knowledge and reasoning at several levels of abstraction and at several different functional views. These principles have been applied with success in the context of a robotic soccer 2D simulation league team through the development of tools and extensive use of these analysis principles.

2007

Simple sensing head geometry using fibre Bragg gratings for strain-temperature discrimination

Authors
Frazao, O; Marques, L; Marques, JM; Baptista, JM; Santos, JL;

Publication
OPTICS COMMUNICATIONS

Abstract
In this work, a simple sensing head geometry using fibre Bragg gratings for strain and temperature discrimination is presented. The sensing head geometry consists in one fibre with two FBGs bonded with a dummy optical fibre. Due to this new configuration, different strain sensitivities of the two FBGs are obtained (approximate to 65% difference), while temperature sensitivities remain the same. This difference in strain sensitivities is substantially larger than in all previously reported dual grating sensors. The obtained experimental errors were +/- 13.48 mu epsilon and +/- 2.44 degrees C, respectively. It is also demonstrated that this new configuration can be used as a temperature-independent strain sensor.

2007

Technology and digital art

Authors
Marcos, AF;

Publication
COMPUTERS & GRAPHICS-UK

Abstract

2007

A historical perspective of legged robots

Authors
Silva, MF; Machado, JAT;

Publication
JOURNAL OF VIBRATION AND CONTROL

Abstract
The objective of this paper is to present the evolution and the state-of-the-art in the area of legged locomotion systems. In a first phase different possibilities for implementing mobile robots are discussed, namely the case of artificial legged locomotion systems, while emphasizing their advantages and limitations. In a second phase a historical overview of the evolution of these systems is presented, bearing in mind several particular cases often considered as milestones of technological and scientific progress. After this historical timeline, some of the present-day systems are examined and their performance is analyzed. In a third phase the major areas of research and development that are presently being followed in the construction of legged robots are pointed out. Finally, some still unsolved problems that remain defying robotics research, are also addressed.

2007

Intelligent mixed reality for the creation of ambient assisted living

Authors
Costa, R; Neves, J; Novais, P; Machado, J; Lima, L; Alberto, C;

Publication
PROGRESS IN ARTIFICIAL INTELLIGENCE, PROCEEDINGS

Abstract
Demographical and social changes have an enormous effect on health care, emergency and welfare services. Indeed, as the average age continues to rise, it is set the mood to an exponential growth in assistance and care, resulting in higher service costs, a decrease in quality of service, or even both. On the other hand, as part of the evolution of traditional Virtual Reality Environments (or Intelligent Mixed Reality), a striving expression for Ambient Intelligence (AmI) it is possible to outline the role of AmI in healthcare, by focusing on its technological, logical (relational) and common sense nature. Our goal is to have in place an electronically-based monitoring system. This would reduce response time to adverse events, improve analytics and reporting, and will provide caregivers with the information they need to positively impact the care of individual patients.

2007

An improved fuzzy inference system for Voltage/VAR control

Authors
Miranda, V; Moreira, A; Pereira, J;

Publication
IEEE TRANSACTIONS ON POWER SYSTEMS

Abstract
This paper describes the concept of a voltage/NAR controller based on an interaction of fuzzy Mamdani controllers, with the main objective of keeping voltages at all busbars inside an admissible band while avoiding line flows to exceed admissible limits. Estimation of sensitivities via fuzzy clustering of load profiles is proposed. A complex rule base interacts with a Newton-Raphson power flow routine in iterative steps until a terminating criterion is met, following a basic min-max approach. Tests to the method reveal it as one order of magnitude faster than a competing simulated annealing routine.

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