1,721,054 research outputs found
Data Quality Evaluation of Scientific Datasets - A Case Study in a Policy Support Context
No full textIn this work we present the rule-based approach used to evaluate the quality of scientific datasets in a policy support context. The used case study refers to real datasets in a context where low data quality limits the accuracy of the analysis results and, consequently, the significance of the provided policy advice. The applied solution consists in the identification of types of constraints that can be useful as data quality rules and in the development of a software tool to evaluate a dataset on the basis of a set of rules expressed in the XML
markup language. As rule types we selected some types of data constraints and dependencies already proposed in data quality works, but we experimented also the use of order dependencies and existence constraints. The case study was used to develop and test the adopted solution, which is anyway generally applicable to other contexts.JRC.G.3 - Maritime affair
Optimal comparison strategies in Ulam's searching game with two errors
No full textAbstractSuppose x is an n-bit integer. By a comparison question we mean a question of the form “does x satisfy either condition a ⩽x ⩽b or c ⩽x ⩽d?”. We describe strategies to find x using the smallest possible number q(n) of comparison questions, and allowing up to two of the answers to be erroneous. As proved in this self-contained paper, with the exception of n = 2, q(n) is the smallest number q satisfying Berlekamp's inequality 2q⩾2nq2+ q + 1. This result would disappear if we only allowed questions of the form “does x satisfy the condition a⩽x⩽b?”. Since no strategy can find the unknown x ∈ {0,1,…,2n −1} with less than q(n) questions, our result provides extremely simple optimal searching strategies for Ulam's game with two lies—the game of Twenty Questions where up to two of the answers may be erroneous
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