342 research outputs found
Reminiscences on Influential Papers
No full textReminiscences on Parallel evaluation of multi-join queries. (Proc. SIGMOD Conf. 1995), Annita Wilschut, Jan Flokstra, Peter M.G. Apers
Preface
No full textThis volume provides much-needed coverage of the technical background to the development of multimedia applications. Based on an advanced summer school run by the University of Twente, each chapter is written by an expert in a particular topic, including enabling technologies, operating systems, index structures for multimedia, and communication issues. There is also a comprehensive discussion of the factors which determine the success or failure of database applications in the real-world, based on new multimedia projects in Dutch industries and service companies. Multimedia Databases in Perspective is an advanced textbook aimed at final year undergraduate students, and MSc and PhD students studying databases, database management, information systems, and multimedia applications. It will also be of interest to researchers in the above areas, and DBMS developers working in the software industry
Flexible and scalable digital library search
No full textThe everlasting search for new methods to explore the Inter- or Intranet is still going on. In this demo we present the combined effort of the AMIS and DMW research projects, each covering significant parts of this problem.
The contribution of this demo is twofold. Firstly, we demonstrate how feature grammars offer a flexible solution for extraction and querying of meta-data from multimedia documents in general. Scalability and efficiency support are illustrated for full text indexing and retrieval. Secondly, we show how for a more limited domain, like an Intranet, conceptual modeling can offer additional and more powerful query facilities. The limited domain case, also allows the extraction and querying of high-level concepts from raw video data
Sound ranking algorithms for XML search in PF/Tijah
No full textWe argue that ranking algorithms for XML should reflect the actual
combined content and structure constraints of queries, while at the
same time producing equal rankings for queries that are semantically
equal. Ranking algorithms that produce different rankings for queries
that are semantically equal are easily detected by tests on large
databases: We call such algorithms {em not sound}. We report the
behaviour of different approaches to ranking content-and-structure
que-ries on pairs of queries for which we expect equal ranking results
from the query semantics. We show that most of these approaches are
not sound. Of the remaining approaches, only 3 adhere to the W3C XQuery
Full-Text standard
Database Optimization Aspects for Information Retrieval
No full textThere is a growing need for systems that can process queries, combining both structured data and text. One way to provide such functionality is to integrate information retrieval (IR) techniques in a database management system (DBMS). However, both IR and database research have been separate research fields for decades, resulting in different - even conflicting - approaches to data management. Each DBMS has a component called a "query optimizer", which plays a crucial role in the efficiency and flexibility of the system. So, for successful integration the IR techniques and data structures, as well as the DBMS query optimizer, should be adapted to enable mutual cooperation. The author concentrates on top-N queries - a common class of IR queries. An IR top-N query asks for the N best documents given a set of keywords. The author proposes processing the data in batches as a compromise between IR and DBMS query processing. Experiments with this technique show that porting IR optimization techniques is (still) not a promising option due to the additional administrative overhead. Two new mathematical models are introduced to eliminate this overhead: a model that predicts selectivity, which is a crucial factor in the execution costs, and a model that predicts the quality of the top-N
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