Automatic Mapping Between Large-Scale Heterogeneous Language Resources for NLP Applications: A Case of Sejong Semantic Classes and KorLexNoun for Korean

Park, Heum,Yoon, Ae-Sun Korean Society for Language and Information 2011 언어와 정보 Vol.15 No.2

This paper proposes a statistical-based linguistic methodology for automatic mapping between large-scale heterogeneous languages resources for NLP applications in general. As a particular case, it treats automatic mapping between two large-scale heterogeneous Korean language resources: Sejong Semantic Classes (SJSC) in the Sejong Electronic Dictionary (SJD) and nouns in KorLex. KorLex is a large-scale Korean WordNet, but it lacks syntactic information. SJD contains refined semantic-syntactic information, with semantic labels depending on SJSC, but the list of its entry words is much smaller than that of KorLex. The goal of our study is to build a rich language resource by integrating useful information within SJD into KorLex. In this paper, we use both linguistic and statistical methods for constructing an automatic mapping methodology. The linguistic aspect of the methodology focuses on the following three linguistic clues: monosemy/polysemy of word forms, instances (example words), and semantically related words. The statistical aspect of the methodology uses the three statistical formulae ${\chi}^2$, Mutual Information and Information Gain to obtain candidate synsets. Compared with the performance of manual mapping, the automatic mapping based on our proposed statistical linguistic methods shows good performance rates in terms of correctness, specifically giving recall 0.838, precision 0.718, and F1 0.774.

Why Korean Is Not a Regular Language: A Proof

No, Yong-Kyoon Korean Society for Language and Information 2001 언어와 정보 Vol.5 No.2

Natural language string sets are known to require a grammar with a generative capacity slightly beyond that of Context Free Grammars. Proofs regarding complexity of natural language have involved particular properties of languages like English, Swiss German and Bambara. While it is not very difficult to prove that Korean is more complex than the simplest of the many infinite sets, no proof has been given of this in the literature. I identify two types of center embedding in Korean and use them in proving that Korean is not a regular set, i.e. that no FSA's can recognize its string set. The regular language i salam i (i salam ul$)^j$ michi (key ha)^k$ essta is intersected with Korean, to give {i salam i (i salam ul$)^j$ michi (key ha$)^k$ essta i $$\mid$$ j, k $\geq$ 0 and j $\leq$ k}. This latter language is proved to be nonregular. As the class of regular sets is closed under intersection, Korean cannot be regular.

Derivational Interpretation of Korean “wh-phrases”

Kim, Ae-Ryung Korean Society for Language and Information 2002 언어와 정보 Vol.6 No.2

In this paper I develop a mechanism of interpreting Korean “wh-phrases”. The phrases have various readings depending on where they occur and they could be ambiguous even in the same structure. Yet their readings are subject to certain restrictions. I assume that the “wh-phrases” behave like variables and that there are three quantifiers to bind the phrases; $COMP_{wh},\;COMP_{conc}$ and derivational $\exists$-quantifier. Based on the assumptions I suggest derivational quantification, which consists of three conditions. 1) A quantifier can bind only when it merges into the derivation; 2) $\exists$-quantifier accompanies 〔-OP〕 complementizer but its activation is optional; 3) an instance of quantification makes the clause opaque to other instances of quantification. Scrambling data support derivational approach and across-the-board interpretation motivates the opacity condition. The opacity condition accounts for ATB- interpretations of reflexive pronouns. It can also explain the island effect of wh-islands without adopting covert wh-movement in Korean.

Sentiment Analysis of Korean Using Effective Linguistic Features and Adjustment of Word Senses

Jang, Ha-Yeon,Shin, Hyo-Pil Korean Society for Language and Information 2010 언어와 정보 Vol.14 No.2

This paper introduces a new linguistic-focused approach for sentiment analysis (SA) of Korean. In order to overcome shortcomings of previous works that focused mainly on statistical methods, we made effective use of various linguistic features reflecting the nature of Korean. These features include contextual shifters, modal affixes, and the morphological dependency of chunk structures. Moreover, in order to eschew possible confusion caused by ambiguous words and to improve the results of SA, we also proposed simple adjustment methods of word senses using KOLON ontology mapping information. Through experiments we contend that effective use of linguistic features and ontological information can improve the results of sentiment analysis of Korean.

Focus Types and Gradients in Korean Case Ellipsis

Lee, Han-Jung Korean Society for Language and Information 2008 언어와 정보 Vol.12 No.2

This paper examines the effects of focus types on case ellipsis in Korean. A number of previous studies have suggested that accusative case markers in Korean and Japanese cannot be dropped when the object they mark is contrastively focused (Masunaga, 1988; Yatabe, 1999; Ko, 2000; Lee, 2002). Using experimental evidence, we argue against the view that case ellipsis in Korean is sensitive to the distinction between contrastive vs. non-contrastive focus. An alternative analysis is proposed which accounts for the phenomenon of variable case marking in terms of the interaction between the contrastive strength and the discourse accessibility of focused object NPs. By viewing patterns of case ellipsis as the result of balancing between these two forces, such an analysis can correctly predict the gradient pattern of case ellipsis shown by the three types of focused objects tested in the experiment (contrastive replacing focus, contrastive selecting focus and non-contrastive, informational focus), while at the same time offering an explanation for why subtypes of focus exert distinct influences on case ellipsis.

Processing Nominal Suffixes in Korean: Evidence from Priming Experiments

Ahn, Hee-Don,An, Duk-Ho,Choi, Jung-Yun,Hwang, Jong-Bai,Jeon, Moon-Gee,Kim, Ji-Hyon Korean Society for Language and Information 2011 언어와 정보 Vol.15 No.1

This study investigates morphologically complex nouns in Korean through a series of priming studies. Two experiments examined whether morphological affixes on Korean nouns were decomposed or processed as a whole. Two types of morphological affixes were examined: morpho-syntactic case markers and the plural marker '-tul'. Results showed that priming occurred for the plural marker with SOAs of 80 ms and 160 ms, but no priming occurred for the morpho-syntactic case markers. These results suggest that the morphological processing for these two types of affixes differ. We argue that Korean nouns with the plural suffix are decomposed into the stem and affix, supporting the Decomposition Model (Pinker & Ullman, 2002). We suggest that while plural markers are truly morphological affixes, case markers in Korean are morpho-syntactic, and thus presuppose the existence of other syntactic elements, such as the matrix verb, hence the lack of priming effects.

Nominative/Accusative Adpositions in Negative Auxiliary Constructions

No, Yong-Kyoon Korean Society for Language and Information 2004 언어와 정보 Vol.8 No.2

The nominative and accusative postpositions in Korean may intervene between the negative auxiliary verb ANH and its complement verb phrase. As Korean is an OV language, this means that 'verb + {nom, acc} + ANH' as well as the simpler concatenation 'verb + ANH' is possible. This fact, together with an overwhelming regularity of these postpositions' optionality in virtually all constructions, poses a problem for formal approaches to the syntax of the language. Working in a constraint-based grammatical framework shaped by such works as Sag and Wasow (1999) and Copestake (2002), we put forth type hierarchies for major_class, which represents verb inflection, and for pos, which has two immediate subtypes, i.e., htrp_pos and ord_pos. What we call the 'half transparency' of the case postpositions separates them from all the other lexical items in the language. The type htrp_pos is used to constrain one of the two newly proposed head_comp_rules, where a newly proposed feature HEAD2 of a phrase inherits its value from the HEAD feature of the head word. The COMPS list of the negative auxiliary ANH is seen as containing a single phrase whose HEAD is a kind of nominal clause and whose HEAD2 is something that is one of the three maximal types: acc, nom, and null.

Unaccusativity in Korean

Lee, Sang-Ki Korean Society for Language and Information 2007 언어와 정보 Vol.11 No.2

Since Perlmutter (1978) proposed the Unaccusativity Hypothesis, the past two decades have seen a flourish of studies investigating the potential validity of unaccusativity in Korean. The central contentious issues have been whether unaccusativity can also be assumed in Korean, and, if so, what criteria could be proposed to discern the unaccusativity among various predicates. In this paper, several suggestions made theoretically and experimentally to address the semantic and/or syntactic distinction of the two types of Korean intransitive predicates are critically reviewed and evaluated from the standpoint that there is a close correlation between syntax and lexical semantics of intransitives. It is proposed, then, that the Korean unaccusativity can be reliably differentiated through the combined semantic criteria of [${\pm}$agentive] and [${\pm}$active]. In addition, case alternations in long form negation constructions are shown to be the most reliable and valid syntactic criteria for testing Korean unaccusatives.

On Subjunctives in Korean: Exploiting a Bilingual Corpus

Song, Sanghoun Korean Society for Language and Information 2014 언어와 정보 Vol.18 No.1

This paper provides a corpus study on subjunctives in Korean in a way of comparative semantics. The whole arguments of this paper are bolstered by distributional evidence taken from naturally occurring bitexts (i.e. a bilingual corpus), in which one sentence in a language is aligned with one translation in the other language. Since previous studies regard past tense morphology as the main component to express irrealis and uncertainty, this paper accordingly checks out whether the past tense morpheme (e/a)ss in Korean is also responsible for conveying the meaning of subjunctives. My finding is that the past tense morpheme (e/a)ss is a sufficient condition for forming subjunctives in Korean. The current corpus study verifies that the past tense morpheme is not obligatorily used in present conditional counterfactuals in Korean, unlike English. Yet, if (e/a)ss is used and the antecedent denotes a present situation, the conditional sentence can only be interpreted as conveying counterfactuality. On the other hand, wish constructions in Korean, irrespective of the semantic tense, often contain the past tense morpheme. Hence, this work substantiates Iatridou (2000)'s theory of 'fake past tense' is applicable to Korean subjunctives. The present corpus study, additionally, reveals that a conditional marker telamyen is a component of expressing past counterfactuals in Korean.

Ordering a Left-branching Language: Heaviness vs. Givenness

Choi, Hye-Won Korean Society for Language and Information 2009 언어와 정보 Vol.13 No.1

This paper investigates ordering alternation phenomena in Korean using the dative construction data from Sejong Corpus of Modern Korean (Kim, 2000). The paper first shows that syntactic weight and information structure are distinct and independent factors that influence word order in Korean. Moreover, it reveals that heaviness and givenness compete each other and exert diverging effects on word order, which contrasts the converging effects of these factors shown in word orders of right-branching languages like English. The typological variation of syntactic weight effect poses interesting theoretical and empirical questions, which are discussed in relation to processing efficiency in ordering.