98,351 research outputs found
Functional Dependencies Unleashed for Scalable Data Exchange
We address the problem of efficiently evaluating target functional
dependencies (fds) in the Data Exchange (DE) process. Target fds naturally
occur in many DE scenarios, including the ones in Life Sciences in which
multiple source relations need to be structured under a constrained target
schema. However, despite their wide use, target fds' evaluation is still a
bottleneck in the state-of-the-art DE engines. Systems relying on an all-SQL
approach typically do not support target fds unless additional information is
provided. Alternatively, DE engines that do include these dependencies
typically pay the price of a significant drop in performance and scalability.
In this paper, we present a novel chase-based algorithm that can efficiently
handle arbitrary fds on the target. Our approach essentially relies on
exploiting the interactions between source-to-target (s-t) tuple-generating
dependencies (tgds) and target fds. This allows us to tame the size of the
intermediate chase results, by playing on a careful ordering of chase steps
interleaving fds and (chosen) tgds. As a direct consequence, we importantly
diminish the fd application scope, often a central cause of the dramatic
overhead induced by target fds. Moreover, reasoning on dependency interaction
further leads us to interesting parallelization opportunities, yielding
additional scalability gains. We provide a proof-of-concept implementation of
our chase-based algorithm and an experimental study aiming at gauging its
scalability with respect to a number of parameters, among which the size of
source instances and the number of dependencies of each tested scenario.
Finally, we empirically compare with the latest DE engines, and show that our
algorithm outperforms them
Business Models and their Implications for Skills
The dominant political-economic narrative of our time is that, under conditions of global competition with low-wage economies able to undercut even efficient western firms, the only viable and sustainable route to competitiveness is to trade on high value-added goods and services and that these in turn require enhanced skills and knowledge. This kind of analysis finds echo and sustenance in the management literature concerning 'knowledge'. Drawing upon a series of case studies this monograph reveals a more varied and complex pattern of possibilities
A complementing approach for identifying ethical issues in care robotics – grounding ethics in practical use
We use a long-term study of a robotic eating-aid for disabled users to illustrate how empirical use give rise to a set of ethical issues that might be overlooked in ethic discussions based on theoretical extrapolation of the current state-of-the-art in robotics. This approach provides an important complement to the existing robot ethics by revealing new issues as well as providing actionable guidance for current and future robot design. We discuss our material in relation to the literature on robot ethics, specifically the risk of robots performing care taking tasks and thus causing increased isolation for care recipients. Our data identifies a different set of ethical issues such as independence, privacy, and identity where robotics, if carefully designed and developed, can make positive contributions
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