2005 Working Papers
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Item Constructing programs or processes(Working Paper, Department of Computer Science, University of Waikato, 2005-12) Reeves, Steve; Streader, DavidWe define interacting sequential programs, motivated originally by constructivist considerations. We use them to investigate notions of implementation and determinism. Process algebras do not define what can be implemented and what cannot. As we demonstrate it is problematic to do so on the set of all processes. Guided by constructivist notions we have constructed interacting sequential programs which we claim can be readily implemented and are a subset of processes.Item StoneD: A bridge between Greenstone and DSpace(Working Paper, University of Waikato, Department of Computer Science, 2005-04) Witten, Ian H.; Bainbridge, David; Tansley, Robert; Huang, Chi-Yu; Don, Katherine J.Greenstone and DSpace are widely-used software systems for digital libraries, and prospective users sometimes wonder which one to adopt. In fact, the aims of the two are very different, although their domains of application do overlap. This paper describes the systems and identifies their similarities and differences. We also present StoneD, a stone bridge between the production versions of Greenstone and DSpace that allows users of either system to easily migrate to the other, or continue with a combination of both. This bridge eliminates the risk of finding oneself locked in to an inappropriate choice of system. We also discuss other possible opportunities for combining the advantages of the two, to the benefit of the user communities of both systems.Item ApproXFILTER - an approximative XML filter(Working Paper, Department of Computer Science, University of Waikato, 2005-01-01) Michel, Yann-Rudolf; Hinze, AnnikaPublish/subscribe systems filter published documents and inform their subscribers about documents matching their interests. Recent systems have focussed on documents or messages sent in XML format. Subscribers have to be familiar with the underlying XML format to create meaningful subscriptions. A service might support several providers with slightly differing formats, e.g., several publishers of books. This makes the definition of a successful subscription almost impossible. We propose the use of an approximative language for subscriptions.We introduce the design our ApproXFILTER algorithm for approximative filtering in a pub/sub system. We present the results of our analysis of a prototypical implementation.Item Design and implementation of a filter engine for semantic web documents(Working Paper, Department of Computer Science, University of Waikato, 2005-01-01) Kozuka, Takanori; Hinze, AnnikaThis report describes our project that addresses the challenge of changes in the semantic web. Some studies have already been done for the so-called adaptive semantic web, such as applying inferring rules. In this study, we apply the technology of Event Notification System (ENS). Treating changes as events, we developed a notification system for such events.Item Investigating the memory requirements for publish/subscribe filtering algorithms(Working Paper, Department of Computer Science, 2005-01-01) Bittner, Sven; Hinze, AnnikaVarious filtering algorithms for publish/subscribe systems have been proposed. One distinguishing characteristic is their internal representation of Boolean subscriptions: They either require conversions to disjunctive normal forms (canonical approaches) or are directly exploited in event filtering (non-canonical approaches). In this paper, we present a detailed analysis and comparison of the memory requirements of canonical and non-canonical filtering algorithms. This includes a theoretical analysis of space usages as well as a verification of our theoretical results by an evaluation of a practical implementation. This practical analysis also considers time (filter) efficiency, which is the other important quality measure of filtering algorithms. By correlating the results of space and time efficiency, we conclude when to use non-canonical and canonical approaches.