Abstract
Nowadays when utilities are faced with increasing requirements regarding Quality of Service, it is important to be aware that severe contingencies can happen, in an unpredictable way which far exceeds all the security principles used for planning and system operation. In any electricity transmission system, a security condition must be assured - either in steady or in transient state - otherwise the essential service provided to costumers could be severely jeopardized. Present day Quality of Service requirements that are imposed on the electrical utility companies force them to develop efficient processes to analyze and react to incidents that can happen in an unpredictable way and far exceed all the security principles used. The simulation and analysis of these scenarios allow us to minimize the risk of system unbalance and voltage collapse. The steady state simulations of the Portuguese Transmission System were made in PSS/E software from Siemens Power Transmission Distribution, Inc., using savecases that represent pictures of the real system. The simulation results presented focus on aspects like energy not supplied, generation lost and topological changes resulting from an incident, which will affect mainly the power flow distribution within the grid elements that will remain in service (connected) and the voltage level in the system bus-bars. These results allow us to be better prepared to face these severe disturbances, defining procedures for emergency situation and training the control room operators.

Abstract
Recent advances in miniaturization led to the development of what is now called the endoscopic capsule. This small device is swallowed by a patient ana films the whole gastrointestinal tract, allowing the detection of abnormalities. Currently, a doctor typically needs up to two hours to analyze a full exam, so automation is desirable. This paper presents a methodology for measuring the potential of selected visual MPEG-7 descriptors for the task of specific medical event detection such as blood, ulcers. Experiments show that the best results are obtained by the Scalable Color and Homogenous Texture descriptors, especially if only relevant coefficients are used.

Abstract
Recently, the IEEE 802.11 a standard was published as an amendment to the original IEEE 802.11 standard. This amendment is intended to provide differentiated levels of QoS to the supported applications. The 802.11e amendment incorporates an. additional coordination function called Hybrid Coordination. Fraction. (HCF) that uses both a contention-based channel access method, called the Enhanced Distributed Channel Access (EDCA) and a controlled channel access, referred to as the HCF Controlled Channel Access (HCCA). Under the EDCA mechanism, it is a common assumption to consider the highest access category (voice) adequate to support real-time communication. In this paper, we analyze the timing behavior of the EDCA function, when it is used to support real-tune traffic. Basically, we assess the behavior of the voice category in open communication environments (i.e., a communication environment subject to eternal disturbances) when this access category is used to transfer small sized packets, generated in periodic intervals. We show that the transmission opportunity (TXOP) mechanism included in. the IEEE 802.11e amendment improves the system throughput, for the case of message streams with small packet sizes. However, the impact of external disturbances upon the transfer of real-tune messages is highly relevant. For instance, the average access delay for the real-time messages is more than one order of magnitude larger when. the external disturbance increases the network load from just 10% to 30%. Furthermore, both the number of packet losses anal the average size of the MAC queues forecast an. unacceptable number of deadline losses for the real-time message streams, even for intermediate load cases.

Abstract
The aim of the present work is the recognition of human face visual information, in order to automatically control the access to restricted areas, granting access to authorized "clients" and barring the entrance to "impostors". The vision system assembled performed the image acquisition, processing and recognition by first creating a database with a single view of each "client" and then by using multiple test images of each individual candidate to access. To get the test images, a video sequence was captured during the individual's approach path to the camera. Because subjects presented themselves in a random pose before the camera, the synthesis of frontal views was incorporated, by using a view-morphing method. ne modelling and the recognition were handled through the use of ICA methods. The identification of valid "clients" was fully successful. In order to check the rejection of "impostors", a leave-one-out test was performed which gave promising results.

Abstract
The idea of fractional calculus is not new. Fractional derivatives are almost as old as integer-order definition. In 1695 Leibniz discussed this problem with L'Hospital, but many other contributions are due to investigators such as Liouville, Abel, Heaviside and Riemann, that formalized the theory of the non-integer order systems. The area of fractional calculus has primarily been the domain of mathematicians, and only had the theoretical foundation. Nowadays, this concept is employed in physics, engineering, biology, economy and other scientific fields. In our work, we apply the concepts of fractional calculus and the theory of electrical impedance to botanical elements. The fractional order behaviour of these type of systems are studied and the relation with the electrical impedance is formulated.

Abstract
This paper describes a preliminary and innovative approach to integrated cooperative control and navigation of multi robots dynamic formations that encompasses the simultaneous tracking of opponent team players in robotic football games. Unlike traditional approaches that use self-localization to distribute object position estimates, a coordinated approach to cooperative formation navigation is proposed. The control architecture is based in a hierarchic hybrid systems approach, where distributed maneuvers allow simultaneous navigation and coordination. Our main contributions reside in an integrated control and navigation design framework yielding cooperative localization maneuvers and also some specific maneuver results on both formation estimation and global localization of two robots and two landmarks with bearing only measurements. © 2006 IEEE.