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Abstract
Over the last decade, impelled by the industry demand to achieve a technology capable of sending low amount of data payloads, but at the same time with a very low latency and ultra-low power consumption, several efforts in wireless network transmission standardization emerged, supporting new applications in health, sports and fitness, medical, sensor networking, and even the automotive industry field. Despite the competition from ANT+, ZigBee, Nike+, NFC and RF4CE, in 2010 the Bluetooth SIG (special interest groups) adopted a new wireless technology named Bluetooth Low Energy (BLE). BLE coexist with Bluetooth in the same chip (called dual mode) therefore assuring this technology a rapid growth among smartphones, iOS, tablets, laptops and PCs. In fact, Bluetooth SIG also announced that it shall be hard to find a smartphone or tablet-PC that does not integrate BLE in the near future. Despite this accelerated growth, BLE shares the same band with Wi-Fi and all other low power technologies, so in order to achieve QoS, a mandatory requirement in many systems, tests for interference and coexistence must be performed. This study analysis the impact of a BLE sensor network on a crowded 2.4GHz room, with multiple Wi-Fi routers, ZigBee sensors and Bluetooth technology. We also compare the results with the ones obtained inside an anechoic chamber on similar experiences.

Abstract
This paper deals with the problem of active target tracking with obstacle avoidance for multi-robot systems. A nonlinear model predictive formation control is presented which uses potential functions as terms of the cost function. These terms penalize the proximity with mates and obstacles, splitting the problem of obstacle avoidance into two repulse functions. Experimental results with real robots are presented to demonstrate the performance of the approach. © IFAC.

Abstract
A multi-robot system is formed when a group of robots interact with the environment as a single system. This system can also be in formation in order to accomplish tasks rather difficult or impossible to achieve with a single robot. A nonlinear model predictive formation control (NMPFC) was used to converge a group of middle sized mobile soccer robots towards a desired target using the concept of active target tracking. This paper presents a novel approach on formation controller's weight tuning in order to minimize an objective function that reflects the controller's efficiency with respect to a given criteria. Furthermore, the results of simulation and experiment with real robots are presented and discussed.

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This paper aims to examine the process of reservoir sedimentation, namely to try to estimate the sediment volume deposited in the main Portuguese reservoirs. The changes in fluvial sediment transport induced by the construction of dams on the major Portuguese rivers are described. Based on the values of dead volumes, the current situation of 166 Portuguese reservoirs is analysed to obtain an order of magnitude of available sediments and pre-select reservoirs that could potentially be integrated into a project for the artificial sand nourishment of beaches. This work was carried out as a starting point in order to implement a national plan for the use of reservoir sediments as an "added value" to the economy, which is as yet generally unexploited. © 2014 Taylor & Francis Group, London.

Abstract