483 research outputs found
Calculus and Algebra for Distributed Data Management
The sharing of content by communities of users (e.g., scientists)
in a P2P context remains cumbersome. We argue that main reasons
for this is the lack of calculus and algebra for distributed data management.
We present the ActiveXML language that extends the XML language
with features to handle distribution. More precisely, ActiveXML
documents are XML documents with a special syntax for specifying the
embedding of Web service calls, e.g. XML queries such as XQueries. We
also present ActiveXML algebra that extends ActiveXML notably with
explicit control of data exchanges. ActiveXML algebra allows describing
query plans, and exchanging them between peers
Les connaissances de la toile
How to manage knowledge on the Web.Comment: in French; Cultures num\'eriques, \'education aux m\'edias et \`a
l'information (2013
Relational Foundations For Functorial Data Migration
We study the data transformation capabilities associated with schemas that
are presented by directed multi-graphs and path equations. Unlike most
approaches which treat graph-based schemas as abbreviations for relational
schemas, we treat graph-based schemas as categories. A schema is a
finitely-presented category, and the collection of all -instances forms a
category, -inst. A functor between schemas and , which can be
generated from a visual mapping between graphs, induces three adjoint data
migration functors, -inst-inst, -inst -inst, and -inst -inst. We present an algebraic query
language FQL based on these functors, prove that FQL is closed under
composition, prove that FQL can be implemented with the
select-project-product-union relational algebra (SPCU) extended with a
key-generation operation, and prove that SPCU can be implemented with FQL
Queries and computation on the web
AbstractThe paper introduces a model of the Web as an infinite, semistructured set of objects. We reconsider the classical notions of genericity and computability of queries in this new context and relate them to styles of computation prevalent on the Web, based on browsing and searching. We revisit several well-known declarative query languages (first-order logic, Datalog, and Datalog with negation) and consider their computational characteristics in terms of the notions introduced in this paper. In particular, we are interested in languages or fragments thereof which can be implemented by browsing, or by browsing and searching combined. Surprisingly, stratified and well-founded semantics for negation turn out to have basic shortcomings in this context, while inflationary semantics emerges as an appealing alternative
Rule-Based Application Development using Webdamlog
We present the WebdamLog system for managing distributed data on the Web in a
peer-to-peer manner. We demonstrate the main features of the system through an
application called Wepic for sharing pictures between attendees of the sigmod
conference. Using Wepic, the attendees will be able to share, download, rate
and annotate pictures in a highly decentralized manner. We show how WebdamLog
handles heterogeneity of the devices and services used to share data in such a
Web setting. We exhibit the simple rules that define the Wepic application and
show how to easily modify the Wepic application.Comment: SIGMOD - Special Interest Group on Management Of Data (2013
The Digital Shoebox
International audienceThe digital information of our modern world-text, images, videos and the like, can be stored and reproduced massively at almost zero cost. It can be easily dispersed in space to preserve it from both the natural world (fire and water) and the political one (tyrants and censors). So why does it seem so difficult to preserve our digital memory
Qualité, équité, transparence, vérification et explicabilité des décisions algorithmiques
International audienceWe consider aspects, especially technical, of the quality, fairness, transparency, and explainability of algorithmic decisions.Nous considérons des aspects, surtout techniques, de la qualité, l'équité, la transparence, et l'explicabilité des décisions algorithmiques
Introducing Access Control in Webdamlog
We survey recent work on the specification of an access control mechanism in
a collaborative environment. The work is presented in the context of the
WebdamLog language, an extension of datalog to a distributed context. We
discuss a fine-grained access control mechanism for intentional data based on
provenance as well as a control mechanism for delegation, i.e., for deploying
rules at remote peers.Comment: Proceedings of the 14th International Symposium on Database
Programming Languages (DBPL 2013), August 30, 2013, Riva del Garda, Trento,
Ital
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