Abstract
Most of the original image feature detectors are not able to cope with large photometric variations, and their extensions that should improve detection eventually increase the computational cost and introduce more noise to the system. Here we extend the original SURF algorithm increasing its invariance to illumination changes. Our approach uses the local space average color descriptor as working space to detect invariant features. A theoretical analysis demonstrates the impact of distinct photometric variations on the response of blob-like features detected with the SURF algorithm. Experimental results demonstrate the effectiveness of the approach in several illumination conditions including the presence of two or more distinct light sources, variations in color, in offset and scale.

Abstract
This paper describes a power conversion system that implements bidirectional power flow between the electric grid and a battery, based on a full bridge inverter associated with a dual active bridge. A method for power flow control based on the agreement between battery pack and low voltage grid requirements has been developed to allow the large penetration of both, electric vehicles (EV) and renewable microgeneration. A laboratory prototype containing all functions required to implement a vehicle-to-grid (V2G) power interface has been built. The hardware implementation is reported, including control scheme and high-frequency transformer design details. Converter key waveforms are presented to evaluate the power quality on batteries and grid, as well as its dynamic behavior. An experimental laboratory setup is described and results are shown to demonstrate the technical benefits for low-voltage (LV) microgrids, if electric vehicle charger includes a power flow control based on frequency-voltage droop concept. © 2013 IEEE.

Abstract
This paper describes an action-research approach to the specification of an ontology to be applied in the information organisation of a community of forest planning experts. Like many others, a community of forest planning experts does not see their technical domains in unison, rather it voices several points of view that need to be shared and understood. This research started by addressing the practical problem of achieving an effective information structure and organisation for a semantic wiki platform. This was supported by a method and platform for the collaborative specification of ontologies: conceptME. Simultaneously, an empirical study was carried out aiming at understanding better how a technical community pragmatically develops conceptual representations of a domain. The results of this research show the benefits of collaboration in the development of conceptual models for knowledge organisation and information retrieval.

Abstract
The main objective of this project was to evaluate the sensing system for person detection in the scope of its integration in a mobile robotic platform for Ambient Assisted Living. Two sensors were considered, a camera and a depth sensor. For the camera (2D), 3 different algorithms were implemented: face detection, tracking and recognition. For the depth sensor the whole body detection was tested using skeleton tracking. The results showed that the face detection and recognition algorithms had a very small range, and the face tracking demonstrated to reach a higher distance. However, the latter exhibited poor results when confronted with illumination variations. The skeleton tracking algorithm provided good results, being capable of tracking relatively close to the sensor and up to 3 meters distance. Thus, the 2D face recognition can be used for short distances to identify the person, while the 3D skeleton tracking can be appropriated for distant tracking of the person. This work showed that the integration of these sensing systems, in a robotic platform, can make a robust robot capable of human interaction in home environments. © 2013 IEEE.

Abstract
This paper investigates power allocation strategies over a bank of independent parallel Gaussian wiretap channels where a legitimate transmitter and a legitimate receiver communicate in the presence of an eavesdropper and a friendly jammer. We give algorithms to compute the optimal power allocation strategy of the jammer in the degraded scenario. We also give an algorithm to compute power allocations strategies of the jammer in a general scenario, leading to significant performance gains in relation to isotropic jamming. Additionally, we provide a set of results that cast further insight into the problem. In our scenario, which is applicable to current OFDM communications systems, we demonstrate that the proposed jammer power allocation strategy can lead to considerable secrecy gains.

Abstract
Currently, it is an ordinary procedure to restrict the use of renewables, mainly wind power, to accommodate a more stable set of generating units (e.g.: thermal units) to supply the load. The purpose of this paper is to discuss particular aspects from the adequacy and security evaluation of generation and transmission (G&T) system that must be revised due to the massive integration of wind power in the present and future energy systems. By running a sequential Monte Carlo simulation (SMCS) algorithm it is possible to assess the system adequacy identifying possible security constrains. The demonstration cases are based on the modified IEEE-RTS 79 system and a small planned configuration for a real G&T system, typically radial. The results extracted from the case studies illustrate that the impact resulting from the massive integration of renewable sources should not be assessed from the adequacy evaluation perspective without considering system security issues.