Abstract
This article's main goal is to present a review on the principles of ergonomics applied to tools used for e-learning. It is known that the errors in the application of these principles entail cognitive overload on users of these platforms, so the article tries to address the issue comprehensively. Thus, in the first section presents the most notable ergonomic principles as the foundations of Cognitive and Informational Ergonomics and then presents guidelines for the usability of information systems that can serve as support for academic interactions. In the second part, there will be a discussion about some aspects from collaborative learning experiences among teachers and students in research projects and extension. The methodology of this paper points to a research of qualitative nature, where the aim was to understand the interactions virtually experienced by users of systems whose goal is to encourage the construction of the academic knowledge. The results of this research appear as an additional form of analysis of issues related to ergonomics, so that the information systems always prioritize the different profiles of its users.

Abstract
In this work, we address the modeling and control problems in the domain of underwater vehicles. We focus on a prototype of an autonomous underwater vehicle. Although the work presented here is applied to a particular vehicle with four controllable degrees of freedom, the method may be easily extended to several submerged bodies. In the engineering area, modeling of systems is done frequently, as it yields a mathematical translation of their behavior. Since models can become, an important tool to solve problems related to its motion or even to the design of controllers, we obtain a model with six degrees of freedom for such a vehicle. Robust control of underwater vehicles is an area in which many efforts were applied over the last two decades. However, due to nonlinear dynamics, it may be hard to design robust controllers that yield the expected behavior, and there is no general procedure to develop them. Here, we propose an approach that combines nonlinear controllers based on the deduced model and on the Lyapunov theory to control the velocities of the vehicle with linear controllers that control the vehicle's position. We derive control laws to perform several maneuvers, both in the vertical and the horizontal planes, in a decoupled way, which is made possible through the configuration of thrusters. Finally, we present realistic simulations and experimental results that validate the proposed approach in the definition of the control laws.

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Abstract
This paper presents a decentralized architecture for the islanding operation of distribution grids with large volume of distributed generation. This architecture involves the definition of network blocks which share the responsibility of frequency control. The control block abstraction was particularly designed to support the transition from regular grids to smart grids. In addition, the control schemes were developed using an agent-based paradigm. Hence, an agent-based simulation platform was implemented using libraries from the Java Agent Development Framework (JADE). The control schemes were evaluated using a test system with different sorts of distributed energy resources and modeled in the EUROSTAG environment. Simulation results show the effectiveness of the control architecture when different failure events are applied to the test system.

Abstract
This paper is concerned with lightning surge propagation on wind turbines. As wind power generation undergoes rapid growth, lightning incidents involving wind turbines have come to be regarded as a serious problem. Nevertheless, no known studies exist yet in Portugal regarding lightning protection of wind turbines. Hence, we present a case study, based on a wind turbine with an interconnecting transformer, for the analysis of lightning surges. Computer simulations obtained by using the EMTP-RV code are presented. Conclusions are duly drawn.

Abstract
The thermocline is a vertical transition layer in the water column with a strong impact on marine biology, since it affects phytoplankton concentration and, hence, primary production. AUVs can play an important role in understanding this relationship, by sampling the relevant data, usually describing yo-yo patterns spanning the whole water column. In this paper we describe a reactive behavior implemented onboard a small sized AUV, to adapt depth in real time in order to maintain the vehicle in the vicinity of the thermocline and therefore increasing efficiency in the sampling process. Preliminary field tests show that the method is simple, robust and effective. © 2010 IEEE.