• Korean Journal of Logic
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• v.9 no.2
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• pp.1-30
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• 2006

This paper investigates algebraic semantics for some weak Boolean (wB) logics, which may be regarded as left-continuous t-norm based logics (or monoidal t-norm based logics (MTLs)). We investigate as infinite-valued logics each of wB-LC and wB-sKD, and each corresponding first order extension $wB-LC\forall$ and $wB-sKD\forall$. We give algebraic completeness for each of them.

• Language and Information
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• v.13 no.2
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• pp.47-57
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• 2009

It has been observed that not all negative polarity items (NPIs) are licensed in the same negative contexts, and different NPIs may be licensed by different negative expressions. This shows that Ladusaw's (1979) downward entailment is not precise enough to account for the distributional patterns of NPIs (van der Wouden, 1997; van der Wouden and Zwarts, 1993; Zwarts, 1986, among others). One well-known attempt to deal with this issue is to divide negative expressions into several subtypes. Using boolean semantics, Zwarts (1986; 1998) distinguishes three kinds of downward entailing licensors and accounts for heterogeneous NPI-licensing conditions by means of the semantic strength of negative expressions. This approach has been adopted to define Korean negation (Nam, 1994; Chung, 1993; Chung, 1997; Hwang, 2009). In this paper, however, we argue that the boolean semantic approach for negation is not adequate in characterizing the properties of Korean negative expressions and explaining the contexts of licensing Korean NPIs.

• The Transactions of the Korea Information Processing Society
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• v.3 no.5
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• pp.1160-1169
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• 1996

In this study, an experiment of information retrieval using fuzzy connection matrix of keywords was conducted. A query for retrieval was constructed from each keyword and Boolean operator such as AND, OR, NOT. In a workstation environment, the performance of the fuzzy retrieval system was proved to be considerably effective than that of the system using the crisp set theory. And both recall ratio and precision ratio showed that the proposed technique would be a possible alternative in future information retrieval. Some special features of this experimental system were ; ranking the results in the order of connectivity, making the retrieval results correspond flexibly by changing the threshold value, trying to accord the retrieval process with the retrieval semantics by treating the averse-connectivity (fuzzy value) as a semantic approximation between kewords.