http://hdl.handle.net/1880/45287 Wed, 19 Jun 2013 02:37:32 GMT 2013-06-19T02:37:32Z http://hdl.handle.net/1880/46602 Title: COLLIDING PUCKS SOLVED USING A TEMPORAL LOGIC Authors: Cleary, John G. Abstract: A Horn Clause logic programming language, called Starlog, which allows execution of programs involving time is described. A sound and complete bottom up execution procedure for the language is described. An extended example of Programming in Starlog is given in the form of a solution to the colliding pucks problem. A discussion of the features necessary for a distributed implementation of Starlog are given. Tue, 01 Aug 1989 00:00:00 GMT http://hdl.handle.net/1880/46602 1989-08-01T00:00:00Z http://hdl.handle.net/1880/46235 Title: RAY TRACING IN CALGARY AND OTAGO Authors: Wyvill, Geoff; Wyvill, Brian; Cleary, John Abstract: No abstract Sun, 01 Mar 1987 00:00:00 GMT http://hdl.handle.net/1880/46235 1987-03-01T00:00:00Z http://hdl.handle.net/1880/46173 Title: MODELING FOR TEXT COMPRESSION Authors: Bell, Timothy C.; Witten, Ian H.; Cleary, John G. Abstract: The best schemes for text compression employ large models to help them predict which characters will come next. The actual next characters are coded with respect to the prediction, resulting in compression of information. Models are best formed adaptively, based on the text seen so far. This paper surveys successful strategies for adaptive modeling which are suitable for use in practical text compression systems. The strategies fall into three main classes: finite-context modeling, in which the last few characters are used to condition the probability distribution for the next one; finite-state modeling, in which the distribution is conditioned by the current state (and which subsumes finite-context modeling as an important special case); and dictionary modeling, in which strings of characters are replaced by pointers into an evolving dictionary. A comparison of different methods on the same sample texts is included, along with an analysis of future research directions. Tue, 25 Oct 1988 00:00:00 GMT http://hdl.handle.net/1880/46173 1988-10-25T00:00:00Z http://hdl.handle.net/1880/46155 Title: ON THE PRIVACY AFFORDED BY ADAPTIVE TEXT COMPRESSION Authors: Witten, Ian H.; Cleary, John G. Abstract: Ordinary techniques of text compression provide some degree of privacy for messages being stored or transmitted. First, by recoding messages compression protects them from the casual observer. Second, by removing redundancy it denies a cryptanalyst the leverage of the normal statistical regularities in natural language. Third and most important, the best text compression systems use adaptive modeling so that they can take advantage of the characteristics of the text being transmitted. The model acts as a very large key, without which decryption is impossible. Adaptive modeling means that the key depends on the entire text which has been transmitted so far since the time the encoder/decoder system was initialized. This paper introduces the modern approach to text compression and describes a highly effective adaptive method, with particular emphasis on its potential for protecting messages from eavesdroppers. The technique is potentially fast and provides both encryption and data compression. Tue, 01 Sep 1987 00:00:00 GMT http://hdl.handle.net/1880/46155 1987-09-01T00:00:00Z