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This paper considers the problem of scheduling jobs in a permutation flow shop with the objective of minimizing total earliness and tardiness. Unforced idle time is considered in order to reduce the earliness of jobs. It is shown how unforced idle time can be inserted on the final machine. Several dispatching heuristics that have been used for the problem without unforced idle time were modified and tested. Several procedures were also developed that conduct a second pass to develop a sequence using dispatching rules. These procedures were also tested and were found to result in better solutions.

Abstract
Among the wide application areas that Virtual Reality (VR) can have a major impact, one is Education. However, this potential is still unexplored, and one of these gaps has to do with language learning. Listening activities, which are often only supported by audio, are thought of to be demanding area when it comes to learning a second or foreign language and so therefore an interesting area for VR to take place. This pilot study therefore presents the perceptions of foreign language teachers regarding a novel medium for delivering listening activities to their students: Virtual Reality technology. The results show that foreign language teachers are of the opinion that this technology can help motivate students and potentiate the student’s learning curve regarding the listening of a foreign or second language. © Springer Nature Switzerland AG 2019.

Abstract
The progressive decommissioning of large synchronous generators that should take place in face of increasing penetration ratios of Distributed Generation (DG) will demand additional control mechanisms for inertia provision and frequency and voltage regulation in the power system. The need to cope with increasing penetration ratios of DG in distribution grids, added to the necessity to integrate an expected massification of EV and distributed ESS, and to the necessity to enhance Power System resilience and controllability, makes the Smart-Transformer (ST) a suitable solution. In this paper it is demonstrated the feasibility of the ST to contribute to frequency control through the control of the resources available in the distribution AC/DC hybrid networks created from the ST. The feasibility of local droop controllers, acting on frequency and voltage magnitude of the AC/DC hybrid networks created from the ST, to achieve the aforementioned goal, is demonstrated through computational simulation.

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The area of professional training using virtual reality technologies has received considerable investment due to the advantages that virtual reality provides over traditional training. In this paper, we present an experiment whose goal was to analyse the impact that an additional stimulus has on the effectiveness of a virtual environment designed to train firefighters. The additional stimulus is a smell, more specifically the smell of burnt wood, which is consistent with the audiovisual content presented, and the effectiveness of the VE is measured through participant's feeling of presence, cybersickness, fatigue, stress and transfer of knowledge. The results indicate that, although the VE was successful in transferring knowledge, the addition of smell did not influence any of the measured variables. In the discussion section, we present the various factors that we believe have influenced this result. As future work, more experiments will be performed, with other stimuli, to understand better which stimuli increase participant's feeling of presence in the VE.