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Features/Semantic Web (view source)

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'''Comments and Explanations:'''
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There are comments (in italic) providing guidance to fill out each section, see also the [[Features/Policy|Feature Policy Page]] for a more detailed explanation of the new-feature process. '''Copy the source to a ''new page'' named Features/''Your Feature Name'' before making changes!  DO NOT EDIT THIS TEMPLATE.'''
      
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* Targeted release: 0.98
 
* Targeted release: 0.98
 
* Last updated: {{REVISIONTIMESTAMP}}
 
* Last updated: {{REVISIONTIMESTAMP}}
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* Percentage of completion: 20%
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* Percentage of completion: 40%
    
== Detailed Description ==
 
== Detailed Description ==
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The idea is to leverage the flexible RDF data model to encode the data Sugar has to deal with. In association with SPARQL, a query language for RDF, it will be possible to have a universal query system as expressive as SQL but without the constraints imposed by databases (tables of fixed schema).
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The idea is to leverage the flexible RDF data model to encode the data Sugar has to deal with. In association with SPARQL, a query language for RDF, it will be possible to have a universal query system as expressive as SQL but without the constraints imposed by databases (tables with fixed schema).
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The model for the data encoded in RDF is that of a graph with directed labelled edges. The nodes of this graph are resources, for instance a file on the disk or a journal entry. Note that these nodes are are not the resources themselves but a representation of them (i.e. the content of a file is not serialized as the label of a node). Edges between the nodes maps to relations binding resources together. Considering a journal entry and a file, the relation would be that the journal entry has stored the file. This model is flexible as any kind of relation can be created. It is conceptually very close to key/value stores.
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In relation to RDF and SPARQL, the principle of "Linked Data" suggests publishing data by using URIs for both the resources and the relations. The use of URIs removes the risk for ambiguity in data encoding, it also provides an easier integration for multiple languages
    
== Benefit to Sugar ==
 
== Benefit to Sugar ==
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''What is the benefit to the platform?  If this is a major capability update, what has changed?  If this is a new feature, what capabilities does it bring? Why will Sugar become a better platform or project because of this feature?''
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Sugar will benefit from the usage of RDF, SPARQL, and the Linked Data publication scheme at several points:
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* RDF is a standard pushed by the W3C and which is gaining popular adoption by public bodies (UK gov, ...) as well as companies (Facebook, Google, ...). Using that data model in Sugar would ease data integration processes with other data sources already using that format. For instance, an activity will be able to query Wikipedia (actually, DBpedia - it's RDF enabled flavor) for the population of a country, or a list of countries sharing some particular feature. The acquired knowledge could then be stored in the XO and connected to other information.
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''Make sure to note here as well if this feature has been requested by a specific deployment, or if it has emerged from a bug report.''
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* SPARQL is a query mechanism for RDF data that will expose the data contained in Sugar. In a class room, a teacher will be able to query all the XOs for their most used activity and generate statistics with a single SPARQL query sent to all the machines.
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* The implementation of [[Features/Tags_in_Journal]] is facilitated as it maps to picking up tags from a set of pre-defined resources and connected to them with an "hasTag" relation. Rather than being hard-coded within Sugar, the tags can be stored on a SPARQL enabled server on an XS and be queried when needed.
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* Enhanced multi-lang support. For instance, let's consider the tag "Car" and assume a French speaking class and a Spanish class want to use it to tag some activities usage. French pupils will tag "voiture", their Spanish friends will most likely use "coche". Consolidating the two terms as speaking about a car is tricky, data consolidation is better done upfront. Linked Data proposes to solve this issue by picking up a resource for "Car", for instance "http://laptop.org/ontology/Car" and relate it to "voiture"@fr and "coche"@es with a relation "rdf:label". Sugar will then display the french label or the spanish label depending on the locale but always use "http://laptop.org/ontology/Car" in the backend.
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* As illustrated by the previous example, using these technologies will facilitate data integration and re-use between schools, bringing collaborative learning to a new scale.
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* Similarly to the tags, the meta data an activities uses can be controlled via an external data source and a controlled vocabulary.
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* In general, Sugar can be turned into a [http://en.wikipedia.org/wiki/Semantic_desktop Semantic Desktop]. A concept which relates to a better integration of data between desktop applications and across desktops. It will be the first of this kind reaching a young public, that's something worth a bit of PR :)
    
== Scope ==
 
== Scope ==
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''What work do the developers have to accomplish to complete the feature in time for release?  Is it a large change affecting many parts of the distribution or is it a very isolated change? What are those changes?''
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The scope will vary with the degree of adoption to consider. It ranges from installing a python package to let activities query for RDF data to making a complete re-design of the Journal data store.
    
==UI Design==
 
==UI Design==
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''Does the feature have a direct impact on the work flow, or does it need a UI? Link here mockups, or add detailed descriptions.''
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There should be no need for a UI as most of the changes concerns the code of Sugar and activities.
    
== How To Test ==
 
== How To Test ==
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There are currently some beta version of code [https://github.com/cgueret/SemanticXO available on GitHub]
 
{{:{{PAGENAME}}/Testing}}
 
{{:{{PAGENAME}}/Testing}}
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== User Experience ==
 
== User Experience ==
 
''If this feature is noticeable by its target audience, how will their experiences change as a result?  Describe what they will see or notice.''
 
''If this feature is noticeable by its target audience, how will their experiences change as a result?  Describe what they will see or notice.''
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Users will eventually see that:
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* Activities can share information
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* They can directly contribute to the translation of parts of the software
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* They can share and link Journal entries from different instances of Sugar, even if remotely connected
    
== Dependencies ==
 
== Dependencies ==
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''What other packages (RPMs) depend on this package?  Are there changes outside the developers' control on which completion of this feature depends?  In other words, does your feature depend on completion of another feature owned by someone else or that you would need to coordinate, which might cause you to be unable to finish on time?  Other upstream projects like Python?''
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Most noticeably, the implementation of storing RDF data on Sugar and having it queried with SPARQL requires the addition of a triple store. Triple store are RDF databases that are optimized for storing and serving data in that format. Most of the triple stores have been designed for servers are too big to be run on an XO. For now, some [http://semweb4u.wordpress.com/2011/11/02/does-it-scale/ interesting performances] have been reached with [http://www.aelius.com/njh/redstore/ RedStore]. An other alternative to consider would be the popular [http://4store.org/ 4store]. These two seems however to be the only ones usable on the XO hardware, currently none of them is packaged for Fedora.
    
== Contingency Plan ==
 
== Contingency Plan ==
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''If you cannot complete your feature by the final development freeze, what is the backup plan?  This might be as simple as "None necessary, revert to previous release behaviour."  Or it might not.  If your feature is not completed in time, we want to assure others that other parts of Sugar will not be in jeopardy.''
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Well, revert to previous release behaviour should be enough to solve all problems.
    
== Documentation ==
 
== Documentation ==
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''Is there upstream documentation on this feature, or notes you have written yourself?  Has this topic been discussed in the mailing list or during a meeting? Link to that material here so other interested developers can get involved.''
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This feature is being investigated under the contributor project "SemanticXO", it has been explained and demoed at various conferences and demo events. Most of the documentation can be found on the [http://semweb4u.wordpress.com/category/semanticxo/ blog of the project]
    
== Release Notes ==
 
== Release Notes ==
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''The Sugar Release Notes inform end-users about what is new in the release. An Example is [[0.84/Notes]]. The release notes also help users know how to deal with platform changes such as ABIs/APIs, configuration or data file formats, or upgrade concerns.  If there are any such changes involved in this feature, indicate them here.  You can also link to upstream documentation if it satisfies this need.  This information forms the basis of the release notes edited by the release team and shipped with the release.''
      
== Comments and Discussion ==
 
== Comments and Discussion ==
 
* See [[{{TALKPAGENAME}}|discussion tab for this feature]] <!-- This adds a link to the "discussion" tab associated with your page.  This provides the ability to have ongoing comments or conversation without bogging down the main feature page. -->
 
* See [[{{TALKPAGENAME}}|discussion tab for this feature]] <!-- This adds a link to the "discussion" tab associated with your page.  This provides the ability to have ongoing comments or conversation without bogging down the main feature page. -->
Cgueret
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