James C. King

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This paper describes the symbolic execution of programs. Instead of supplying the normal inputs to a program (e.g. numbers) one supplies symbols representing arbitrary values. The execution proceeds as in a normal execution except that values may be symbolic formulas over the input symbols. The difficult, yet interesting issues arise during the symbolic(More)
Current influenza vaccination recommendations focus on immunizing high-risk people; however, influenza mortality and morbidity remain elevated. U.S. policymakers are considering expansion of flu vaccination recommendations to include school-age children (ages 5-18). Children are at risk for flu and propagate epidemic spread. Immunizing children at school(More)
By "program reduction" we mean making a program simpler according to some measure. For the narrow purposes here, that measure is the number of statements in the program. We are interested in the case when an existing program, assumed to be correct, is too general, too big, for a given situations. A simpler program, consistent with the original, but(More)
This paper formally describes a technique for proving that computer programs will always execute correctly. In order to do this, an abstract model for a program and its execution is given. Then, correctnessmodel for a program and its execution is given. Then, correctness of programs and proofs of correctness of programs are defined with respect to that(More)
A study of several of the proof of correctness methods is presented. In particular, the form of induction used is explored in detail. A relational semantic model for programming languages is introduced and its relation to predicate transformers is explored. A rather elementary viewpoint is taken in order to expose, as simply as possible, the basic(More)
This paper explains, in an introductory fashion, the method of specifying the correct behavior of a program by the use of input/output assertions and describes one method for showing that the program is correct with respect to those assertions. An initial assertion characterizes conditions expected to be true upon entry to the program and a final assertion(More)
This paper describes the architecture of a proposed document composition system named JANUS, which is intended to provide support for authors of complex documents containing mixtures of text, line art, and tone art. The JANUS system is highly interactive, providing authors with immediate feedback and direct electronic control over page layouts, using a(More)