Phrase

About: Phrase is a research topic. Over the lifetime, 12580 publications have been published within this topic receiving 317823 citations. The topic is also known as: syntagma & phrases.

Experiments in Automatic Phrase Indexing For Document Retrieval: A Comparison of Syntactic and Non-Syntactic Methods

Abstract: In order for an automatic information retrieval system to effectively retrieve documents related to a given subject area, the content of each document in the system''s database must be represented accurately. This study examines the hypothesis that better representations of document content can be constructed if the content analysis method takes into consideration the syntactic structure of document and query texts. Two methods of automatically generating phrases for use as content indicators have been implemented and tested experimentally. The non-syntactic (or statistical) method is based on simple text characteristics such as word frequency and the proximity of words in text. The syntactic method uses augmented phrase structure rules (production rules) to selectively extract phrases from parse trees generated by an automatic syntactic analyzer. Experimental results show that the effect of non-syntactic phrase indexing is inconsistent. For the five collections tested, increases in average precision ranged from 22.7% to 2.2% over simple, single term indexing. The syntactic phrase indexing method was tested on two collections. Precision figures averaged over all test queries indicate that non-syntactic phrase indexing performs significantly better than syntactic phrase indexing for one collection, but that the difference is insignificant for the other collection. More detailed analysis of individual queries, however, indicates that the performance of both methods is highly variable, and that there is evidence that syntax-based indexing has certain benefits not available with the non-syntactic approach. Possible improvements of both methods of phrase indexing are considered. It is concluded that the prospects for improving the syntax-based approach to document indexing are better than for the non-syntactic approach. The PLNLP system was used for syntactic analysis of document and query texts, and for implementing the syntax-based phrase construction rules. The SMART information retrieval system was used for retrieval experimentation.

Acoustic determinants of phrase boundary perception

Abstract: How three supersegmental variables (amplitude, pitch contour, and duration pattern) influence phrase boundary perception was investigated in two studies. Listeners located the phrase boundary in ambiguous algebraic expressions, such as ’’(A plus E) times O’’ and ’’A plus (E times O).’’ In one experiment, two values of each of three variables (appropriate or neutral) were orthogonally varied, using linear predictive coding analysis–synthesis procedures. There was a total of eight manipulations for each expression. In the other, the three suprasegmental variables were exchanged between the two alternative meanings of an expression, yielding a total of eight manipulations for each expression. Results from the two studies were consistent in showing that listeners use all three cues, and just these three to parse such utterances. That is, it was possible to completely shift the meaning of an expression uttered with one meaning into its alternate meaning by exchanging all three variables. In both studies, the effects of duration pattern and pitch contour were additive in total proportion correct. Possible models of how listeners process pitch and duration information independently in making a parsing decision are discussed.

Code-switching and grammatical theory

Abstract: This chapter discusses some of the descriptive tools that can be used for the analysis. It illustrates the issues involved in trying to unify the grammatical constraints on borrowing with those on code-mixing, in terms of the notion of local coherence imposed by language indices. A discourse-oriented way of determining the base-language is: the language of the conversation. In a structurally oriented model, some element or set of elements determines the base-language: often the main verb, which is the semantic kernel of the sentence, assigning the different semantic roles and determining the state or event expressed by the clause, is taken to determine the base-language. A very complicated issue concerns the relation between qualitative structural and quantitative distributional analysis. Code-switching is the use of two languages in one clause or utterance. As such code-switching is different from lexical borrowing, which involves the incorporation of lexical elements from one language in the lexicon of another language.

Topic and focus in Mayan

Abstract: Most Mayan languages are 'basically' predicate-initial, but various phrases occur before the predicate when they are focussed or topicalized. This paper assumes the framework of Chomsky 1986 and presents a phrase-structural analysis of topic and focus for three Mayan languages (Tzotzil, Jakaltek, Tz'utujil). Three distinct entities are distinguished: the focus and two types of topic, termed here 'internal' and 'external'. Each is argued to occupy a distinct structural position. At the heart of the analysis is an account of intonational phrasing and the distribution of several intonational phrase clitics in Tzotzil and Jakaltek. An algorithm is proposed for deriving intonational phrase structure from surface structure. Syntactic evidence further supports the phrase-structural differences established on prosodic grounds.