Introducing Dynamic Behavior in Amalgamated Knowledge Bases

The problem of integrating knowledge from multiple and heterogeneous sources is a fundamental issue in current information systems. In order to cope with this problem, the concept of mediator has been introduced as a software component providing intermediate services, linking data resources and application programs, and making transparent the heterogeneity of the underlying systems. In designing a mediator architecture, we believe that an important aspect is the definition of a formal framework by which one is able to model integration according to a declarative style. To this purpose, the use of a logical approach seems very promising. Another important aspect is the ability to model both static integration aspects, concerning query execution, and dynamic ones, concerning data updates and their propagation among the various data sources. Unfortunately, as far as we know, no formal proposals for logically modeling mediator architectures both from a static and dynamic point of view have already been developed. In this paper, we extend the framework for amalgamated knowledge bases, presented by Subrahmanian, to deal with dynamic aspects. The language we propose is based on the Active U-Datalog language, and extends it with annotated logic and amalgamation concepts. We model the sources of information and the mediator (also called supervisor) as Active U-Datalog deductive databases, thus modeling queries, transactions, and active rules, interpreted according to the PARK semantics. By using active rules, the system can efficiently perform update propagation among different databases. The result is a logical environment, integrating active and deductive rules, to perform queries and update propagation in an heterogeneous mediated framework.Comment: Other Keywords: Deductive databases; Heterogeneous databases; Active rules; Update

Concurrent rule execution in active databases

Cataloged from PDF version of article.An active DBMS is expected to support concurrent as well as sequential rule execution in an efficient manner. Nested transaction model is a suitable tool to implement rule execution as it can handle nested rule firing and concurrent rule execution well. In this paper, we describe a concurrent rule execution model based on parallel nested transactions. We discuss implementation details of how the flat transaction model of OpenOODB has been extended by using Solaris threads in order to SUppOrt COnCUrrent eXeCUtiOU of rUkS.

Active Databases for Communication Network Management

This paper has two purposes. First is to propose new database language-features for systems used in real-time management. These features enable the specification of change-traces, events and correlation among events, and they do so in a declarative set-oriented fashion. Second is to introduce network management as an important and interesting application of active distributed databases

Cross-continental comparison of the association between the physical environment and active transportation in children : a systematic review

Background: The purpose of this systematic review was to determine the relationship between a wide range of physical environmental characteristics and different contexts of active transportation in 6- to 12-year-old children across different continents. Methods: A systematic search was conducted in six databases (Pubmed, Web of Science, Cinahl, SportDiscus, TRIS and Cochrane) resulting in 65 papers, eligible for inclusion. The investigated physical environmental variables were grouped into six categories: walkability, accessibility, walk/cycle facilities, aesthetics, safety, recreation facilities. Results: The majority of the studies were conducted in North America (n = 35), Europe (n = 17) and Australia (n = 11). Active transportation to school (walking or cycling) was positively associated with walkability. Walking to school was positively associated with walkability, density and accessibility. Evidence for a possible association was found for traffic safety and all forms of active transportation to school. No convincing evidence was found for associations between the physical environment and active transportation during leisure. General safety and traffic safety were associated with active transportation to school in North America and Australia but not associated with active transportation to school in Europe. Conclusions: The physical environment was mainly associated with active transportation to school. Continent specific associations were found, indicating that safety measures were most important in relation to active commuting to school in North America and Australia. There is a need for longitudinal studies and studies conducted in Asia, Africa and South-America and studies focusing specifically on active transportation during leisure

Design for the contact zone. Knowledge management software and the structures of indigenous knowledges

This article examines the design of digital indigenous knowledge archives. In a discussion of the distinction between indigenous knowledge and western science, a decentred perspective is developed, in which the relationship between different local knowledges is explored. The particular characteristics of indigenous knowledges raise questions about if and how these knowledges can be managed. The role of technology in managing indigenous knowledges is explored with examples from fieldwork in India and Kenya and from web-based databases and digital archives. The concept of contact zone is introduced to explore the space in which different knowledges meet and are performed, such as indigenous knowledge and the technoscientific knowledge of the database. Design for the contact zone, this article proposes, is an intra-active and adaptive process for in creating databases that are meaningful for indigenous knowers. The meta-design approach is introduced as a methodology, which may provide indigenous knowers tools for self-representation and self-organisation through design

Standardized toolchain and model development for video quality assessment: the mission of the joint effort group in VQEG

International audienceSince 1997, the Video Quality Experts Group (VQEG) has been active in the field of subjective and objective video quality assessment. The group has validated competitive quality metrics throughout several projects. Each of these projects requires mandatory actions such as creating a testplan and obtaining databases consisting of degraded video sequences with corresponding subjective quality ratings. Recently, VQEG started a new open initiative, the Joint Effort Group (JEG), for encouraging joint collaboration on all mandatory actions needed to validate video quality metrics. Within the JEG, effort is made to advance the field of both subjective and objective video quality measurement by providing proper software tools and subjective databases to the community. One of the subprojects of the JEG is the joint development of a hybrid H.264/AVC objective quality metric. In this paper, we introduce the JEG and provide an overview of the different ongoing activities within this newly started group