Abstract
A recent trend in the field of beat tracking for musical audio signals has been to explore techniques for measuring the level of agreement and disagreement between a committee of beat tracking algorithms. By using beat tracking evaluation methods to compare all pairwise combinations of beat tracker outputs, it has been shown that selecting the beat tracker which most agrees with the remainder of the committee, on a song-by-song basis, leads to improved performance which surpasses the accuracy of any individual beat tracker used on its own. In this paper we extend this idea towards presenting a single, standalone beat tracking solution which can exploit the benefit of mutual agreement without the need to run multiple separate beat tracking algorithms. In contrast to existing work, we re-cast the problem as one of selecting between the beat outputs resulting from a single beat tracking model with multiple, diverse input features. Through extended evaluation on a large annotated database, we show that our multi-feature beat tracker can outperform the state of the art, and thereby demonstrate that there is sufficient diversity in input features for beat tracking, without the need for multiple tracking models.

Abstract
One of the major problems of voltage stability is the reactive power limit of the system. Improving the system's reactive power handling capacity via Flexible AC transmission System (FACTS) devices is a solution for prevention of voltage instability. In this paper it is studied the influence of Static Synchronous Compensators (STATCOM) and Static Var Compensators (SVC) in dynamic Voltage Stability during Low Voltage Ride Through (LVRT), in wind farms. The wind turbines are equipped with pitch control coupled with a Fixed Speed Induction Generator (FSIG). Due to the nature of asynchronous operation, system voltage instability of wind farms based on FSIG is largely caused by the excessive reactive power absorption by FSIG after a fault due to the large rotor slip gained during fault. Wind farm models based on FSIG and equipped with either STATCOM or SVC are developed in EUROSTAG. The Automatic Voltage Regulators (AVR) of the generating units and the turbine speed governors were modeled in detail. Different load models were used and the Under Load Tap Changers (ULTC) were also taken into account. Finally, some conclusions that provide a better understanding of the dynamic voltage stability of a system with FSIG model during LVRT, using various capacities of STATCOM and SVC are pointed out.

Abstract
In the context of an effort to develop methodologies to support the evaluation of interactive system, this paper investigates an approach to detect graphical user interface external bad smells. Our approach consists in detecting user interface external bad smells through model-based reverse engineering from source code. Models are used to define which widgets are present in the interface, when can particular graphical user interface (GUI) events occur, under which conditions, which system actions are executed, and which GUI state is generated next. From these models we obtain metrics that can later be used to identify the smells.

Abstract
Computing the frequency of small subgraphs on a large network is a computationally hard task. This is, however, an important graph mining primitive, with several applications, and here we present a novel multicore parallel algorithm for this task. At the core of our methodology lies a state-of-the-art data structure, the g-trie, which represents a collection of subgraphs and allows for a very efficient sequential search. Our implementation was done using Pthreads and can run on any multicore personal computer. We employ a diagonal work sharing strategy to dynamically and effectively divide work among threads during the execution. We assess the performance of our Pthreads implementation on a set of representative networks from various domains and with diverse topological features. For most networks, we obtain a speedup of over 50 for 64 cores and an almost linear speedup up to 32 cores, showcasing the flexibility and scalability of our algorithm. This paves the way for the usage of such counting algorithms on larger subgraph and network sizes without the obligatory access to a cluster.

Abstract
Current maritime communications rely on expensive or proprietary technology, such as satellite, WiMAX, and narrowband HF radios. Broadband communications are limited to the near shore 3G/4G coverage provided by mobile operators. The usage of unlicensed and IEEE 802.11 networks may provide ship owners a low-cost broadband access to the Internet offshore, enabling real-time navigation applications and voice/video communications, while increasing safety onboard. Also, they can support underwater communications by acting as a bridge between shore and devices operating underwater. In this paper we present a performance evaluation of IEEE 802.11n networks in the 5.8 GHz band in a maritime environment. A point-to-point link was established between a fishing ship and shore. From our tests, communication links up to 7 km at 1 Mbit/s are possible, showing the advantage of using long range IEEE 802.11 links for broadband maritime communications.

Abstract
Virtual labs are more likely to offer a user friendly environment as well as greater flexibility, allowing students to carry out experiments and repeat them as often as necessary. Nevertheless, they do not discard the need for a conventional system as traditional labs are a valuable asset In this context, the student is the centre of the whole process, taking on the main role and is responsible for his/her own learning process, although there may be an extra support through in-class sessions in order to keep him/her in contact with the system, to offer guidance and motivation for the challenges ahead. One of the advantages of virtual experimentation is the opportunity of using a lab in situations which might be impossible otherwise, allowing students to take part in lab sessions; another one is related with its use to improve learning results. Virtual experimentation labs create flexible learning environments suitable for different types of learners, allowing the interactive and systematic development of competences in the various areas of learning and can be used to complement the conventional type of lectures. VEMA is a practical asynchronous software tool devised to meet the needs of students who can't be present in regular lab classes in the Electrical Engineering Department of ISEC (Instituto Superior de Engenharia de Coimbra).