Deregulation and privatization are posing new challenges on both high voltage transmission and distributions systems. Increasingly liberalized markets encourage trading opportunities to be identified and developed. Environmental constraints, such as energy saving, loss minimization and CO 2 reduction features HVDC (High Voltage Direct Current) as preferred solution in heavily loaded power systems; advantages are increased transmission capacity, improved system stability and prevention of cascading disturbances. In this respect, by 2014, a new HVDC interconnection will be in commercial operation between France and Spain. It is designed as two identical but independent voltage source converters (VSC) links between Santa Llogaia (Spain) and Baixas (France), with a nominal active power of 1,000 MW each and a rated DC voltage of ±320 kV (positive -negative pole).This project is Europe's first DC onshore interconnection integrated in the synchronous AC grid.

Abstract-Better sensing is crucial to improve robotic grasping and manipulation. Most robots currently have very limited perception in their manipulators, typically only fingertip position and velocity. Additional sensors make richer interactions with the objects possible. In this paper, we present a versatile, robust and low cost sensor for robot fingertips, that can improve robotic grasping and manipulation in several ways: 3D reconstruction of the shape of objects, material surface classification, and object slip detection. We extended TUMRosie, our robot for mobile manipulation, with fingertip sensors on its humanoid robotic hand, and show the advantages of the fingertip sensor integrated in our robot system.

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The aim of this paper is to show how compact mmWave radar systems, attached to a person, can take advantage of their movements, in order to significantly improve the image resolution by means of synthetic aperture radar (SAR) techniques. Thus, high resolution imaging becomes possible even with tiny on-chip systems, opening up a horizon of possibilities to assist visually impaired people. The approach is illustrated for movements in terms of arm swings. For this purpose, it is firstly shown that the information from an inertial measurement unit (IMU) can be used to provide a trajectory estimation, which is enough to apply synthetic aperture radar processing. As a consequence, the resolution of the radar is greatly improved when compared with that achieved considering a single position. In order to avoid the continuously growing position error, commonly observed in dead-reckoning systems relying just on IMU, zero velocity updates (ZUPT) will be systematically applied. For doing so, two different zero velocity detectors (ZVD) are considered, one based on acceleration data and other on velocity estimation. Although the positioning information is extracted from the IMU, demonstrating the enhanced obstacle detection capabilities obtained with this approach, other sensors that can be carried by a person and that are capable of providing trajectory estimations to combine measurements acquired with compact mmWave radars could have been used. The system is tested using different targets and a good performance comparable to the one achieved by using a high accuracy reference positioning system is attained. The compactness of the system enables the possibility of using it as a wearable device, e.g., attached to the wrist. This shows that an IMU is enough for tracking relatively simple movements, though more complex positioning systems can be used for more general actions.INDEX TERMS Freehand imaging, visually impaired, inertial measurement unit, mmWave radar, synthetic aperture radar (SAR), wrist mounted imager, zero velocity detectors (ZVD).

This paper aims at contributing to the specialized literature on experimental characterization of metasurfaces reflectivity. Growing demand on angularly stable metasurfaces reinforces the relevance of the results under oblique incidence. Generally, reflection coefficient phase measurements are more challenging than the amplitude ones. Thus, an artificial magnetic conductor (AMC) is used to analyze the critical aspects for enlarging the angular margin that can be properly measured. The importance of the retrieving methodology along with the proposed data post-processing is highlighted among the involved issues, according to the obtained results. The suitability of monostatic vs bi-static measurement set-ups for comparison with plane-wave simulation is studied. The aforementioned AMC is experimentally characterized using both set-ups providing relevant conclusions. The trade-off between the manufactured prototype dimensions (to resemble the simulated infinite one) vs the required anechoic chamber size (to fulfil far-field (FF) conditions i.e. plane wave incidence for the considered frequencies) is tackled. Indeed, a thorough literature revision shows that most authors do not have this key aspect into account. The relevance of the resulting error from comparisons between near-field (NF) retrieved measurements vs plane-wave simulation results is unveiled. This is even more critical when the angular stability is analysed, since the scattering patterns of the AMC are not conformed at near-field distances, which makes the errors even greater. Consequently, noteworthy conclusions concerning the characterization of AMCs in particular and metasurfaces in general, regarding far-field or near-field measurements and angular stability analysis will be presented.