• Title/Summary/Keyword: Context-Free Grammar

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A One-Gap Parsing with Extended PLR(1) Grammars (확장된 PLR(1) 문법에 대한 단일 틈 파싱)

  • Lee, Gyung-Ok
    • Journal of KIISE
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    • v.42 no.3
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    • pp.361-366
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    • 2015
  • Gap parsing is an algorithm for parsing incomplete input strings which include some gaps. Gap parsing is different from conventional parsing, and as known results, one-gap parsing algorithms for arbitrary context-free grammar and LL(1) grammar have $O(n^3)$ and $O(n^2)$ time complexity, respectively. This paper presents a one-gap parsing algorithm for extended PLR(1) grammars. Extended PLR(1) grammars are the class of grammars smaller than LR(1) but much larger than LL(1). The one-gap parsing algorithm of the grammar class is shown to have the time complexity of $O(n^2)$, which is equal to the complexity of one-gap parsing algorithms for LL(1) grammars.

An Abstract Grammar for XML Document Editing (XML 문서 편집을 위한 추상문법)

  • 신경희;최종명;유재우
    • Journal of KIISE:Software and Applications
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    • v.30 no.3_4
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    • pp.268-277
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    • 2003
  • A document type definition(DTD) which defines tags for a document is a XML document grammar that defines syntactic structure of a document. An XML document keeps the rules and must be parsed to check validation. To parse XML document, the deterministic parsing method of programming language is irrelevant because it does not satisfy the definition of deterministic content model in element declaration. In this paper, we consider editing of a valid XML document in syntax-directed editing environment, and we suggest the internal storage representations of syntax in DTD and theirs algorithms. The consequence is that a syntactic structure of textual DTD is transformed into graph and table structures. The table structure of DTD is interpreted the context free grammar which has attribute values and is used in syntax-directed editor for XML. We called this the XML abstract grammar and showed generated results and examples.

Korean Syntactic Rules using Composite Labels (복합 레이블을 적용한 한국어 구문 규칙)

  • 김성용;이공주;최기선
    • Journal of KIISE:Software and Applications
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    • v.31 no.2
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    • pp.235-244
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    • 2004
  • We propose a format of a binary phrase structure grammar with composite labels. The grammar adopts binary rules so that the dependency between two sub-trees can be represented in the label of the tree. The label of a tree is composed of two attributes, each of which is extracted from each sub-tree so that it can represent the compositional information of the tree. The composite label is generated from part-of-speech tags using an automatic labeling algorithm. Since the proposed rule description scheme is binary and uses only part-of-speech information, it can readily be used in dependency grammar and be applied to other languages as well. In the best-1 context-free cross validation on 31,080 tree-tagged corpus, the labeled precision is 79.30%, which outperforms phrase structure grammar and dependency grammar by 5% and by 4%, respectively. It shows that the proposed rule description scheme is effective for parsing Korean.

Inference of Context-Free Grammars using Binary Third-order Recurrent Neural Networks with Genetic Algorithm (이진 삼차 재귀 신경망과 유전자 알고리즘을 이용한 문맥-자유 문법의 추론)

  • Jung, Soon-Ho
    • Journal of the Korea Society of Computer and Information
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    • v.17 no.3
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    • pp.11-25
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    • 2012
  • We present the method to infer Context-Free Grammars by applying genetic algorithm to the Binary Third-order Recurrent Neural Networks(BTRNN). BTRNN is a multiple-layered architecture of recurrent neural networks, each of which is corresponding to an input symbol, and is combined with external stack. All parameters of BTRNN are represented as binary numbers and each state transition is performed with any stack operation simultaneously. We apply Genetic Algorithm to BTRNN chromosomes and obtain the optimal BTRNN inferring context-free grammar of positive and negative input patterns. This proposed method infers BTRNN, which includes the number of its states equal to or less than those of existing methods of Discrete Recurrent Neural Networks, with less examples and less learning trials. Also BTRNN is superior to the recent method of chromosomes representing grammars at recognition time complexity because of performing deterministic state transitions and stack operations at parsing process. If the number of non-terminals is p, the number of terminals q, the length of an input string k, and the max number of BTRNN states m, the parallel processing time is O(k) and the sequential processing time is O(km).

A Design and Implementation of WML Compiler for WAP Gateway for Wireless Internet Services (무선 인터넷 서비스를 위한 WAP 게이트웨이용 WML 컴파일러의 설계 및 구현)

  • Choi, Eun-Jeong;Han, Dong-Won;Lim, Kyung-Shik
    • Journal of KIISE:Computing Practices and Letters
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    • v.7 no.2
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    • pp.165-182
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    • 2001
  • In this paper, we describe a design and implementation of the Wireless Markup Language(WML) compiler to deploy wireless Internet services effectively. The WML compiler translates textual WML decks into binary ones in order to reduce the traffic on wireless links that have relatively low bandwidth to wireline links and mitigate the processing overhead of WML decks on, wireless terminals that have relatively low processing power to fixed workstations. In addition, it takes over the overhead of eXtensible Markup Language(XML) well-formedness and validation processes. The WML compiler consists of the lexical analyzer and parser modules. The granunar for the WML parser module is LALR(1) context-free grammar that is designed based on XML 1.0 and WML 1.2 DTD(Document Type Definition) with the consideration of the Wireless Application Protocol Binary XML grammar. The grammar description is converted into a C program to parse that grammar by using parser generator. Even though the tags in WML will be extended or WML DTD will be upgraded, this approach has the advantage of flexibility because the program is generated by modifying just the changed parts. We have verified the functionality of the WML compiler by using a WML decompiler in the public domain and by using the Nokia WAP Toolkit as a WAP client. To measurethe compressibility gain of the WML compiler, we have tested a large number of textual WML decks and obtained a maximum 85 %. As the effect of compression is reduced when the portion of general textual strings increases relative to one of the tags and attributes in a WML deck, an extended encoding method might be needed for specific applications such as compiling of the WML decks to which the Hyper Text Markup Language document is translated dynamically.

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Continuous Speech Recognition Using N-gram Language Models Constructed by Iterative Learning (반복학습법에 의해 작성한 N-gram 언어모델을 이용한 연속음성인식에 관한 연구)

  • 오세진;황철준;김범국;정호열;정현열
    • The Journal of the Acoustical Society of Korea
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    • v.19 no.6
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    • pp.62-70
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    • 2000
  • In usual language models(LMs), the probability has been estimated by selecting highly frequent words from a large text side database. However, in case of adopting LMs in a specific task, it is unnecessary to using the general method; constructing it from a large size tent, considering the various kinds of cost. In this paper, we propose a construction method of LMs using a small size text database in order to be used in specific tasks. The proposed method is efficient in increasing the low frequent words by applying same sentences iteratively, for it will robust the occurrence probability of words as well. We carried out continuous speech recognition(CSR) experiments on 200 sentences uttered by 3 speakers using LMs by iterative teaming(IL) in a air flight reservation task. The results indicated that the performance of CSR, using an IL applied LMs, shows an 20.4% increased recognition accuracy compared to those without it. This system, using the IL method, also shows an average of 13.4% higher recognition accuracy than the previous one, which uses context-free grammar(CFG), implying the effectiveness of it.

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Digital License Prototype for Copyright Management of Software Source Code (소프트웨어 소스 코드의 저작권 관리를 위한 디지털 라이센스 프로토타입)

  • Cha, Byung-Rae;Jeong, Jong-Geun;Oh, Soo-Lyul
    • Journal of Internet Computing and Services
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    • v.7 no.5
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    • pp.95-108
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    • 2006
  • The digital contents expand into software source code and maintenance of technology and IPR about source code have a very important meaning to international competition, The recognition about software security is very low specially among these Intellectual Property Rights. On occurring disputation property, we have to prove the fact, there is a problem to discriminate the original source code, Also, it is hard to accurate decision that is correct to complexity and the lack of read and understand ability even if software is reproduced. In this paper, we don't enforce distinction about software reproduction by one individual code unit. And we developed digital license prototype of XML that can distinguish reproduction based on structural conformability of whole source codes. Software has Context Free Grammar in structure and presents BNF notation type, it is apt to present hierarchical structure. Then, we can express architecture of software source code by hierarchical structure to discriminate structural conformability. In this paper, we make a study of the digital licence prototype for discriminate the original source code. Reserved words of software source code by parsing express to XML file that have hierarchical structure. Then, we can express architecture of software source code by tree structure form instead of complex source code.

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Designing the Moving Pattern of Cleaning Robot based on Grammatical Evolution with Conditional Probability Table (문법적 진화기법과 조건부 확률을 이용한 청소 로봇의 이동 패턴 계획)

  • Gwon, Soon-Joe;Kim, Hyun-Tae;Ahn, Chang Wook
    • KIISE Transactions on Computing Practices
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    • v.22 no.4
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    • pp.184-188
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    • 2016
  • The cleaning robot is popularly used as a home appliance. The state-of-the-art cleaning robot can clean more efficiently by using information gathered from its sensor, which is difficult for low-price cleaning robots due to limitation in this aspect. In this paper, we suggested a method for the moving pattern of cleaning robot based on grammatical evolution. Optimized program is generated by using moving pattern grammar, which is defined by Backus-Naur form. In addition, conditional probability is used between each of the grammar elements during the program creation process. The proposed method is evaluated by robot simulation in order to verify its performance and further compare it with existing algorithms. The experiment results showed that the proposed method is better than the compared algorithms.

A LR Parsing Algorithm for Tree Adjoining Grammar (트리 접합 문법의 LR파싱 알고리즘)

  • 한성국
    • Korean Journal of Cognitive Science
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    • v.6 no.3
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    • pp.41-63
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    • 1995
  • We present a LR,bottom-up parsing algorithms for TAG. We will introduce the adjoining rules system to handle the formal properties of TAG and to describe the parsing process more effectively. We will consider the context-free behavior of TAG at the adjoining instant. Then we will present the LR bottom up parsing algorithm for TAG by using this property. The basic idea behind a LR bottom up parsing algorithm can be applied to parsing TAG with other conventional algorithms.

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A Korean Flight Reservation System Using Continuous Speech Recognition

  • Choi, Jong-Ryong;Kim, Bum-Koog;Chung, Hyun-Yeol;Nakagawa, Seiichi
    • The Journal of the Acoustical Society of Korea
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    • v.15 no.3E
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    • pp.60-65
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    • 1996
  • This paper describes on the Korean continuous speech recognition system for flight reservation. It adopts a frame-synchronous One-Pass DP search algorithm driven by syntactic constraints of context free grammar(CFG). For recognition, 48 phoneme-like units(PLU) were defined and used as basic units for acoustic modeling of Korean. This modeling was conducted using a HMM technique, where each model has 4-states 3-continuous output probability distributions and 3-discrete-duration distributions. Language modeling by CFG was also applied to the task domain of flight reservation, which consisted of 346 words and 422 rewriting rules. In the tests, the sentence recognition rate of 62.6% was obtained after speaker adaptation.

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