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For disaster mitigation as well as for urban search and rescue (USAR) missions, it is often necessary to place sensors or cameras into dangerous or inaccessible areas to get a better situation awareness for the rescue personnel, before they enter a possibly dangerous area. Robots are predestined to this task, but the requirements for such mobile systems are… (More)
Reordering more than traditional joins (e.g. outerjoins, antijoins) requires some care, since not all reorderings are valid. To prevent invalid plans, two approaches have been described in the literature. We show that both approaches still produce invalid plans. We present three conflict detectors. All of them are (1) correct, i.e., prevent invalid plans,… (More)
We fill two gaps in the literature. First, we give a comprehensive set of equivalences allowing reordering of grouping with non-inner joins. Second, we show how to incorporate the optimal placement of grouping into a state-of-the-art dynamic programming (DP)-based plan generator.
A theoretical prediction by de Gennes suggests that the resistance in a FI/S/FI (where FI is a ferromagnetic insulator, and S is a superconductor) structure will depend on the magnetization direction of the two FI layers. We report a magnetotransport measurement in a EuS/Al/EuS structure, showing that an infinite magnetoresistance can be produced by tuning… (More)
Proposal This proposal describes the innovative and competitive lunar payload solution developed at the Queensland University of Technology (QUT) – the LunaRoo: a hopping robot designed to exploit the Moon's lower gravity to leap up to 20m above the surface. It is compact enough to fit within a 10cm cube, whilst providing unique observation and mission… (More)
It has been a recognized fact for many years that query execution can benefit from pushing group-by operators down in the operator tree and applying them before a join. This so-called eager aggrega-tion reduces the size(s) of the join argument(s), making join evaluation faster. Lately, the idea enjoyed a revival when it was applied to outer joins for the… (More)