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<Paper uid="C88-2158">
  <Title>Object-Oriented Parallel Parsing for Context-Free Grammars</Title>
  <Section position="2" start_page="0" end_page="0" type="abstr">
    <SectionTitle>
Abstract
</SectionTitle>
    <Paragraph position="0"> This paper describes a new parallel parsing scheme for context-free grammars and our experience of implementing this scheme, and it also reports the result of our simulation for running the parsing program on a massive parallel processor.</Paragraph>
    <Paragraph position="1"> In our basic parsing scheme, a set of context freegrammar :,:ules is represented by a network of processor-like computing agents each having its local memory. Each computing agent in the network corresponds to an occurfence of a non-terminal or terminal symbol appearing in the grammar rules. Computing agents in the network work concurrently and communicate with one another by passing messages which are partial parse trees.</Paragraph>
    <Paragraph position="2"> This scheme is shown to he fast (0(n,h) time for the first complete parse tree, where n is the length of an input sentence and h is the height of the parse tree) and useful in various modes of parsing such as on-line parsing, overlap parsing, on-line unparsing, pipe-lining to semantics processing, etc. Performance evaluation for implementing this scheme on a massive parallel machine is conducted by distributed event simulation using the Time Warp mechanism /Jeffersong5/.</Paragraph>
    <Paragraph position="3"> Our parsing scheme is implemented in a programming language called ABCL/1 which is designed for object-oriented concurrent programming and used for various concurrent programming/Yonezawa86/. The program is currently runing on standard single-cpu nlachines such as SUN3s and Symbolics Lisp machines (by simulated parallelism). null In our experiment and simulation, a set of about 250 context-free grammar rules specifying a subset of English is represented by the corresponding network of objects (i.e., computing agents) and about 1100 concurrently executable objects are involved.</Paragraph>
  </Section>
class="xml-element"></Paper>