Uncertainty of Rough Sets in Different Knowledge Granularities
Uncertainty of Rough Sets in Different Knowledge Granularities
复制标题
不同知识粒度下粗糙集的不确定性
DOI:
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发表时间:
2008
影响因子:
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通讯作者:
Wang Guo-Yin
中科院分区:
文献类型:
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作者:
Zhang Qing-Hua;Wang Guo-Yin
Rougness,rough entropy,fuzziness,and fuzzy entropy are major methods for measuring the uncertainty of rough sets.In different knowledge granularity levels,a hierarchical knowledge space chain is proposed based on the attributes in information systems.Some regularities of the changing of rough entropy and fuzziness of a rough set with the knowledge granularity are found to be inconsistent with human cognition.A new method for measuring the fuzziness of rough sets is proposed based on information entropy.The fuzziness measured by the new method is monotonously decreasing with the refining of knowledge granularity in apporiximation spaces.It overcomes the problem of roughness and rough entropy.Finally,the relations of the changing of roughness and fuzziness are analyzed in different knowledge granularities.