Abstract
Over the past two decades, the fact that many games have been formulated as variational inequalities problems has led to relevant developments related with the existence and uniqueness of equilibriums, and with their calculation methodologies. Based on this approach, this study applies sufficient conditions for Cournot equilibriums existence and uniqueness, proving that while existence holds, uniqueness cannot be proved in general. To find one of the existent equilibriums, this study also proposes a novel variational inequalities algorithm which is globally convergent and easy to implement. It iteratively computes searching directions of the equilibrium by generating hyper-planes that separate the equilibrium from the intermediate solutions obtained relaxing the original Cournot game. Unlike other related algorithms, the proposed algorithm does not require Jacobian matrixes evaluation, and the iterative relaxed games can easily be solved using convex and quadratic optimisation models. Numerical results show the operation and convergence of the algorithm.

Abstract
The combination of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) is a powerful tool to study brain function. In this study, we present a video-EEG-fMRI system where in-bore video, EEG and fMRI are acquired synchronously. To determine the added value of video in a typical EEG-fMRI scenario, we analyzed a simple motor activation paradigm (right index tapping). By using in-bore video, our results show that it is possible to determine different EEG potentials related to motion as well as to clearly distinguish the corresponding blood oxygen level dependent activations.

Abstract
Wireless Mesh Networks (WMNs), which feature infrastructureless broadband network configurations, are attracting attention as an elemental technology when it comes to the extension of current WLAN infrastructures. State of the art solutions addressing WMNs usually assume the use of omnidirectional antennas. In this paper we evaluate the performance improvements obtained when using directional antennas. By using simulations, we analyze the gains in terms of throughput, delay and fairness, considering a grid network topology used to extend an infrastructure network. Simulation results show that by changing the type of antenna in use from omnidirectional to directional, the average throughput of a WMN can increase about 56% and the average network delay can be reduced by approximately 40%, without compromising fairness. © 2010 IEEE.

Abstract
Unstructured peer-to-peer overlay networks are very resilient to churn and topology changes, while requiring little maintenance cost. Therefore, they are an infrastructure to build highly scalable large-scale services in dynamic networks. Typically, the overlay topology is defined by a peer sampling service that aims at maintaining, in each process, a random partial view of peers in the system. The resulting random unstructured topology is suboptimal when a specific performance metric is considered. On the other hand, structured approaches (for instance, a spanning tree) may optimize a given target performance metric but are highly fragile. In fact, the cost for maintaining structures with strong constraints may easily become prohibitive in highly dynamic networks. This chapter discusses different techniques that aim at combining the advantages of unstructured and structured networks. Namely we focus on two distinct approaches, one based on optimizing the overlay and another based on optimizing the gossip mechanism itself. © 2010 Springer Science+Business Media, LLC.

Abstract
This paper introduces several different indices in order to characterize the voltage stability of a power system. Voltage instability is a phenomenon which often contributes to the development of power system disturbances. Therefore, is very important to know how a power system is close to voltage collapse. The feasibility of the reported methods is shown by numerical studies in IEEE 57 bus test system. The simulation results are in close agreement.

Abstract
This paper presents a methodology for evaluating the impact resulting from the expected large scale integration of micro-generation (µG) in Low Voltage (LV) grids in Portugal. The proposed methodology allows the evaluation of the impacts in the entire LV and Medium Voltage (MV) distribution network by using typical load and generation profiles (24 hours) representing two well defined year periods (Summer and Winter). The simulations were performed in a time interval from 2008 to 2030, upon the definition of future scenarios related to the expected µG installed power in Portugal in the same period. Based on the obtained results, it was possible to quantify percentage gains related to the reduction of energy losses as a result of µ G integration in LV networks, avoided CO2 emissions and the possibility of achieving investment deferrals due to branches' congestion levels reduction or voltage profile improvements. ©2010 IEEE.