607 research outputs found

    Using Links to prototype a Database Wiki

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    Both relational databases and wikis have strengths that make them attractive for use in collaborative applications. In the last decade, database-backed Web applications have been used extensively to develop valuable shared biological references called curated databases. Databases offer many advantages such as scalability, query optimization and concurrency control, but are not easy to use and lack other features needed for collaboration. Wikis have become very popular for early-stage biocuration projects because they are easy to use, encourage sharing and collaboration, and provide built-in support for archiving, history-tracking and annotation. However, curation projects often outgrow the limited capabilities of wikis for structuring and efficiently querying data at scale, necessitating a painful phase transition to a database-backed Web application. We perceive a need for a new class of general-purpose system, which we call a Database Wiki, that combines flexible wiki-like support for collaboration with robust database-like capabilities for structuring and querying data. This paper presents DBWiki, a design prototype for such a system written in the Web programming language Links. We present the architecture, typical use, and wiki markup language design for DBWiki and discuss features of Links that provided unique advantages for rapid Web/database application prototyping

    Van der Waals interactions between excited atoms in generic environments

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    We consider the the van der Waals force involving excited atoms in general environments, constituted by magnetodielectric bodies. We develop a dynamical approach studying the dynamics of the atoms and the field, mutually coupled. When only one atom is excited, our dynamical theory suggests that for large distances the van der Waals force acting on the ground-state atom is monotonic, while the force acting in the excited atom is spatially oscillating. We show how this latter force can be related to the known oscillating Casimir--Polder force on an excited atom near a (ground-state) body. Our force also reveals a population-induced dynamics: for times much larger that the atomic lifetime the atoms will decay to their ground-states leading to the van der Waals interaction between ground-state atoms.Comment: 19 pages, 4 figure

    A system overview of the Aerospace Safety Research and Data Institute data management programs

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    The NASA Aerospace Safety Information System, is an interactive, generalized data base management system. The on-line retrieval aspects provide for operating from a variety of terminals (or in batch mode). NASIS retrieval enables the user to expand and display (review) the terms of index (cross reference) files, select desired index terms, combine sets of documents corresponding to selected terms and display the resulting records. It also allows the user to print (record) this information on a high speed printer if desired. NASIS also provides the ability to store the strategy of any given session the user has executed. It has a searching and publication ability through generalized linear search and report generating modules which may be performed interactively or in a batch mode. The user may specify formats for the terminal from which he is operating. The system features an interactive user's guide which explains the various commands available and how to use them as well as explanations for all system messages. This explain capability may be extended, without program changes, to include descriptions of the various files in use. Coupled with the ability of NASIS to run in an MTT (multi-terminal task) mode is its automatic accumulation of statistics on each user of the system as well as each file

    Automatic Verification of Transactions on an Object-Oriented Database

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    In the context of the object-oriented data model, a compiletime approach is given that provides for a significant reduction of the amount of run-time transaction overhead due to integrity constraint checking. The higher-order logic Isabelle theorem prover is used to automatically prove which constraints might, or might not be violated by a given transaction in a manner analogous to the one used by Sheard and Stemple (1989) for the relational data model. A prototype transaction verification tool has been implemented, which automates the semantic mappings and generates proof goals for Isabelle. Test results are discussed to illustrate the effectiveness of our approach

    DATA CONSTRUCTORS: ON THE INTEGRATION OF RULES AND RELATIONS

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    Although the goals and means of rule-based and data-based systems are too different to be fully integrated at the present time, it seems appropriate to investigate a closer integration of language constructs and a better cooperation of execution models for both kinds of approaches. In this paper, we propose a new language construct called constructor that â when applied to a base relation â causes relation membership to become true for all tuples constructable through the predicates provided by the constructor definition. The approach is shown to provide expressive power at least equivalent to PROLOG's declarative semantics while blending well both with a strongly typed modular programming language and with a relational calculus query formalism. A three-step compilation, optimization, and evaluation methodology for expressions with constructed relations is described that integrates constructors with the surrounding database programming environment. In particular, many recursive queries can be evaluated more efficiently within the set-construction framework of database systems than with proof-oriented methods typical for a rule-based approach.Information Systems Working Papers Serie

    Adapting to a Design-Based Professional Learning Intervention

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    Designing a systematic inquiry-based, and knowledge-building experience through continuous professional learning for teachers is a key challenge for school authorities. A total of 26 teachers, five principals, three researchers, one graduate student, and two contract professionals from a university were involved in a research-practice partnership. The partners engaged in a yearlong design-based professional learning series. In this study, design-based research was used as the methodology to understand the participant responses to professional learning during the design, enactment, and refinement phases used to design the professional learning series. Open-ended survey responses, researcher field notes and documents from the professional learning sessions were analyzed throughout the study and during three phases of the learning design. The results indicated there were four key shifts and corresponding adaptations made by the participants as they responded to and engaged in a continuous model of professional learning
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