Abstract. We describe a tutorial that demonstrates the use of the ACL2 theorem prover. We have three goals: to enable a motivated reader to start on a path towards effective use of ACL2; to provide ideas for other interactive theorem prover projects; and to elicit feedback on how we might

This tutorial paper explores the mechanics of protecting computer-stored information from unauthorized use or modification. It concentrates on those architectural structures--whether hardware or software--that are necessary to support information protection. The paper develops in three main

The technology for building knowledge-based systems by inductive inference from examples has been demonstrated successfully in several practical applications. This paper summarizes an approach to synthesizing decision trees that has been used in a variety of systems, and it describes one such system, ID3, in detail. Results from recent studies show ways in which the methodology can be modified to deal with information that is noisy and/or incomplete. A reported shortcoming of the basic algorithm is discussed and two means of overcoming it are compared. The paper concludes with illustrations of current research directions.

Most current statistical natural language processing models use only local features so as to permit dynamic programming in inference, but this makes them unable to fully account for the long distance structure that is prevalent in language use. We show how to solve this dilemma with Gibbs sampling, a simple Monte Carlo method used to perform approximate inference in factored probabilistic models. By using simulated annealing in place of Viterbi decoding in sequence models such as HMMs, CMMs, and CRFs, it is possible to incorporate non-local structure while preserving tractable inference. We use this technique to augment an existing CRF-based information extraction system with long-distance dependency models, enforcing label consistency and extraction template consistency constraints. This technique results in an error reduction of up to 9 % over state-of-the-art systems on two established information extraction tasks. 1

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Software reuse is the process ofcreating software systems from existing software rather than building software systems from scratch. ‘l’his simple yet powerful vision was introduced in 1968. Software reuse has, however, failed to become a standard software engineering practice. In an attempt to understand why, researchers have renewed their interest in software reuse and in the obstacles to implementing it. This paper surveys the different approaches to software reuse found in the research literature. It uses a taxonomy to describe and compare the different approaches and make generalizations about the field of software reuse. The taxonomy characterizes each reuse approach interms of its reusable artifacts and the way these artifacts are abstracted, selected, speciahzed, and integrated. Abstraction plays a central role in software reuse. Concise and expressive abstractions are essential if software artifacts are to be effectively reused. The effectiveness of a reuse technique can be evaluatedin terms of cognztzue dwtance-an intuitive gauge of the intellectual effort required to use the technique. Cognitive distance isreduced in two ways: (l) Higher level abstractions ina reuse technique

ACL2 is a theorem proving system under development at Computational Logic, Inc., by the authors of the Boyer-Moore system, Nqthm, and its interactive enhancement, Pc-Nqthm, based on our perceptions of some of the inadequacies of Nqthm when used in large-scale verification projects. Foremost among

ACL2 is the latest inception of the Boyer-Moore theo-rem prover, the 2005 recipient of the ACM Software Sys-tem Award. In the hands of an expert, it feels like a finely tuned race car, and it has been used to prove some of the most complex theorems ever proved about commercially de-signed systems

Faikenhainer, B. and K.D. Forbus, Compositional modeling: finding the right model for the job, Artificial Intelligence 51 ( 1991 ) 95-143.