1,721,004 research outputs found

    Specifying Message Formats with Contiguity Types

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    We introduce Contiguity Types, a formalism for network message formats, aimed especially at self-describing formats. Contiguity types provide an intermediate layer between programming language data structures and messages, offering a helpful setting from which to automatically generate decoders, filters, and message generators. The syntax and semantics of contiguity types are defined and used to prove the correctness of a matching algorithm which has the flavour of a parser generator. The matcher has been used to enforce semantic well-formedness conditions on complex message formats for an autonomous unmanned avionics system

    A Reference Version of HOL

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    . The second author has implemented a reference version of the HOL logic (henceforth called gtt). This version, written in Standard ML, is as simple as possible, making as few assumptions as necessary to present the essence of HOL. This simplicity makes the implementation easy to understand, to port, to develop, to change, and to informally reason about. The first author has ported gtt to another dialect of ML, and developed the parsing, prettyprinting, and typechecking support needed to take gtt beyond its initial rudimentary conception. The implementation of gtt has already been of use in developing a variant of the HOL logic. As of this writing, there are at least four or five extant implementations of the HOL logic. These have been intensively developed, in some cases over decades, which leads us to an overwhelming question: why another? In particular, why gtt? There are several answers to this, stemming from different desires and needs in the HOL community. Changing the logic a ..

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed

    Wellfounded Schematic Definitions

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    Adding New Rules to an LCF-style Logic Implementation

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    Function definition in higher-order logic

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    A parameterized proof manager

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    AC unification in HOL90

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