Browsing by Subject "Expert systems"
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Item Open Access The effects of structural characteristics of explanations on use of a DSS(Elsevier, 2006) Gönül, M. S.; Önkal D.; Lawrence, M.Research in the field of expert systems has shown that providing supporting explanations may influence effective use of system developed advice. However, despite many studies showing the less than optimal use made of DSS prepared advice, almost no research has been undertaken to study if the provision of explanations enhances the users' ability to wisely accept DSS advice. This study outlines an experiment to examine the effects of structural characteristics of explanations provided within a forecasting DSS context. In particular, the effects of explanation length (short vs. long) and the conveyed confidence level (weak vs. strong confidence) are examined. Strongly confident and long explanations are found to be more effective in participants' acceptance of interval forecasts. In addition, explanations with higher information value are more effective than those with low information value and thus are persuasive tools in the presentation of advice to users.Item Open Access Involving fuzzy concepts in active mobile databases(Springer, 1998-08) Saygın, Yücel; Ulusoy, ÖzgürCurrent needs of industry required the development of advanced database models like mobile databases, active databases, and fuzzy databases. Fuzzy concepts are adapted to the field of databases in order to deal with ambiguous, uncertain data. Fuzziness comes into picture in mobile databases especially with moving objects. Incorporating fuzziness into rules would improve the effectiveness of active databases. Rules can be utilized in mobile databases to form a more powerful system, namely an active mobile database. In this paper we investigate the ways in which the concepts developed for fuzzy systems can be integrated to active mobile databases. © Springer-Verlag Berlin Heidelberg 1998.Item Open Access Topic-Centric Querying of Web Information Resourcest(Springer, Berlin, Heidelberg, 2001) Altıngövde, İsmail Şengör; Özel, Selma A.; Ulusoy, Özgür; Özsoyoğlu G.; Özsoyoğlu, Z.M.This paper deals with the problem of modeling web information resources using expert knowledge and personalized user information, and querying them in terms of topics and topic relationships. We propose a model for web information resources, and a query language SQL-TC (Topic-Centric SQL) to query the model. The model is composed of web-based information resources (XML or HTML documents on the web), expert advice repositories (domain-expert-specified metadata for information resources), and personalized information about users (captured as user profiles, that indicate users’ preferences as to which expert advice they would like to follow, and which to ignore, etc). The query language SQL-TC makes use of the metadata information provided in expert advice repositories and embedded in information resources, and employs user preferences to further refine the query output. Query output objects/tuples are ranked with respect to the (expert-judged and user- preference-revised) importance values of requested topics/metalinks, and the query output is limited by either top n-ranked objects/tuples, or objects/tuples with importance values above a given threshold, or both. © Springer-Verlag Berlin Heidelberg 2001.Item Open Access Unification-based approach for knowledge base verification(1991) Polat, F.; Guvenir, H. A.Knowledge base verification, a part of the validation process in expert system development, includes checking the knowledge base for completeness and consistency to guard against a variety of errors that can arise during the process of transferring expertise from a human expert to a computer system. Regardless of how an expert system is developed, its developers can profit from a systematic check of the knowledge base without gathering extensive data for test runs, even before the full reasoning mechanism is functioning. Until recently knowledge base verification has been largely ignored, which has led to expert systems with knowledge base errors and no safety factors for correctness. We propose a unification-based approach for verification of a knowledge base represented in the form of production rules and facts. This approach can determine conflicting, redundant, subsumed and circular rules; redundant if-conditions in rules; dead-end rules; and cycles and contradiction in rules.Item Open Access View maintenance in object-oriented databases(Springer, 1996-09) Alhajj, Reda; Polat, F.in this paper, we present a model that facilitates view maintenance within object-oriented databases. For that purpose, we differentiate between two categories of classes, base classes and brother classes. While the former constitute the actual database, the latter are introduced to hold virtual database, i.e., views derived from base classes. To achieve incremental view update, we introduce a modification list into each base class. A series of algorithms are developed to serve the purpose. Finally it happened that, view maintenance within object-oriented databases subsumes that within the nested and hence conventional relational models.