This paper examines the requirements for building database management systems and multi-database information resources to support molecular biology research. The paper profiles the most important features of 16 integrated resources and 102 databases related to molecular biology research. The aspects surveyed in this paper include the nature of information in these databases, their sizes, update properties, cross-references, database management system heterogeneity, geographical distribution, data quality, use of temporal information and level of interpretation. The paper also comments on the access patterns to these databases. Since not all these aspects were available for all databases, specific comparisons sometimes compare fewer than the full 102 databases. Consequently, the same set of databases is not necessarily always being compared with respect to every aspect. The paper is organized primarily according to these comparison aspects and ends with some concluding remarks.

In this paper a new method to improve the utilization of main memory systems is presented. The new method is based on prestoring in main memory a number of query answers, each evaluated out of a single memory page. To this end, the ideas of page-answers and page-traces are formally described and their properties analyzed. The query model used here allows for selection, projection, join, recursive queries as well as arbitrary combinations. We also show how to apply the approach under update traffic. This concept is especially useful in managing the main memories of an important class of applications. This class includes the evaluation of triggers and alerters, performance improvement of rule-based systems, integrity constraint checking, and materialized views. These applications are characterized by the existence at compile time of a predetermined set of queries, by a slow but persistent update traffic, and by their need to repetitively reevaluate the query set. The new approach represents a new type of intelligent database caching, which contrasts with traditional caching primarily in that the cache elements are derived data and as a consequence, they overlap arbitrarily and do not have a fixed length. The contents of the main memory cache are selected based on the data distribution within the database, the set of fixed queries to preprocess, and the paging characteristics. Page-answers and page-traces are used as the smallest indivisible units in the cache. An efficient heuristic to select a near optimal set of page-answers and page-traces to populate the main memory has been developed, implemented, and tested. Finally, quantitative measurements of performance benefits are reported.

The authors present the design principles of MCFS, an expert system building tool based on the idea of combining multiple criteria reasoning with the concepts of fuzzy logic. An important feature of MCFS is its ability to handle multiple criteria reasoning by structuring the deduction process into a hierarchy of logical levels. Within each level, the rules are organized into sets of rules and rule set groups. The concepts of fuzzy logic are introduced by allowing uncertainty within each rule, each set of rules, and each rule set group. MCFS has been fully implemented and applied to several domains of knowledge such as computer system selection and procurement, solution of nonlinear simultaneous equations, neck-tie selection, and longevity estimation. Experiments with these applications indicate that, compared to standard expert system tools, MCFS produces expert systems which are easier to build and better match the human expert.>

Computing queries from derived relations, optimizing queries from a group of queries, and updating materialized views are important database problems and have attracted much attention. One thing common to these problems is their demand to quickly solve the implication problem — given two predicates σQ and στ, can σQ imply στ (σQ→στ)? The implication problem has been solved by converting it into a satisfiability problem. Based on a graph representation, a detailed study of the general implication problem on its own is presented in this paper. We proved that the general implication problem, in which all six comparison operators: =, ≠, <, >, ≤, ≥, as well as conjunctions and disjunctions are allowed, is NP-hard. In the case when “≠” operators are not allowed in σQ and disjunctions are not allowed in στ, a polynomial time algorithm is proposed to solve this restricted implication problem. The influence of the “≠” operator and disjunctions are studied. Our theoretical results show that for some special cases the polynomial complexity algorithm can solve the implication problem which allows the “≠” operator or disjunctions in the predicates. Necessary conditions for detecting when the “≠” operator and disjunctions are allowed are also given. These results are very useful in creating heuristic methods.

The ability to quickly determine how to derive a given query from a set of prestored fragments is highly demanded in many database applications, especially in distributed database systems, where the communication cost is a major concern. The main difficulty in solving this problem lies in the implication problem given two predicates σQ and σT, can σQ imply σT(σQ → σT)? The implication problem has been solved by converting it into a satisfiability problem. No detailed study of the implication problem on its own has been presented. In this paper, we study the general implication problem in which all six comparison operators: = , ǂ <, =, ≤, ≥, as well as conjunctions and disjunctions are allowed. We proved that the general implication problem is NP-hard. In the case when “ ǂ” operators are not allowed in σQ and disjunctions are not allowed in σT, a polynomial time algorithm is proposed to solve this restricted implication problem. The influence of the “ ǂ ” operator and disjunctions are studied. Our theoretical results show that for some special cases the polynomial complexity algorithm can solve the implication problem which allows the operator or disjunctions in the predicates. Necessary conditions for detecting when the operator and disjunctions are allowed are also given. These results are very useful in creating heuristic methods. © 1989 IEEE

Article Free Access Share on A model of data distribution based on texture analysis Authors: Nabil Kamel Department of Computer Science, University of Colorado, Boulder Colorado, 80309Department of Computer Science, University of Colorado, Boulder Colorado Department of Computer Science, University of Colorado, Boulder Colorado, 80309Department of Computer Science, University of Colorado, Boulder ColoradoView Profile , Roger King Department of Computer Science, University of Colorado, Boulder Colorado, 80309Department of Computer Science, University of Colorado, Boulder Colorado Department of Computer Science, University of Colorado, Boulder Colorado, 80309Department of Computer Science, University of Colorado, Boulder ColoradoView Profile Authors Info & Claims SIGMOD '85: Proceedings of the 1985 ACM SIGMOD international conference on Management of dataMay 1985 Pages 319–325https://doi.org/10.1145/318898.318929Published:01 May 1985Publication History 17citation240DownloadsMetricsTotal Citations17Total Downloads240Last 12 Months18Last 6 weeks2 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF