linked data selectors

Technische Universität Darmstadt

Linked Data Selectors

Kai Michael Höver & Max Mühlhäuser

Telecooperation Group

Telecooperation

OUTLINE• Context and motivation• LDS ontology design• Usage examples

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Ecosystem definition

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"ecosystem, the complex of living organisms, their physical environment, and all their interrela7onships in a par7cular unit of space." [Enyclopedia Britannica]

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(E-)Learning Ecosystem

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"ecosystem, the complex of living organisms, their (physical) environment, and all their interrela7onships in a par7cular unit of space."

organisms may be:-‐ educators-‐ students-‐ friends-‐ family rela7ves-‐ ...

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(physical/e-‐) learning environment contains informa7on resources such as-‐ slides-‐ lecture recordings-‐ documents-‐ forum discussions-‐ Web documents-‐ ...

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learning space where learning and teaching take place-‐ physical-‐ lecture hall-‐ lab-‐ café-‐ in the park

-‐ electronical/virtual-‐ LMS-‐ discussion forums-‐ blogs-‐ OSNs-‐ MOOCs-‐ ...

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interrela7onships between-‐ people (social networks)-‐ people and informa7on resources (author, usage, etc.)-‐ informa7on resources (seman7c rela7ons)

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"ecosystem, the complex of living organisms, their (physical) environment, and all their interrela7onships and interac7ons in a par7cular unit of space."

I‘d add interac7ons between-‐ people (social interac7ons)-‐ people and informa7on resources (how people interact with learning resources)

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Web of knowledge

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Diagramcontradicts

Diagram

illustrates

Wikipedia articleexplains

Forum discussion

Q&A

Lecture Material

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The importance of anchoring annotations

•Annotation types [Agosti2007]:• annotations as metadata: add information about the annotated information• annotations as content: augment with additional content (add notes to an educational resource for explaining or clarifying)

• annotations as dialogue acts: communication acts like a request or a discourse

• "Both annotations and annotated objects need to be uniquely identified" [Agosti2007]• Anchored discussions within a specific content are more directed

and "to-the-point" [Pol2006] • The majority of students use well-specified anchors like underlines or circles on paper [Marshall2002]

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Agosti, M., & Ferro, N. (2007). A formal model of annotations of digital content. ACM Trans. Inf. Syst., 26(1), 3:1-3:57Marshall, C. C., & Brush, A. J. B. (2002). From personal to shared annotations. In CHI '02: CHI '02 extended abstracts on human factors in computing systems (pp. 812-813). ACMPol, J., Admiraal, W., & Simons, P. R. J. (2006). The affordance of anchored discussion for the collaborative processing of academic texts. International Journal of Computer-

Supported Collaborative Learning, 1(3), 339-357

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Missing relations in learning ecosystems

• Problem:• Interrelationships are not (always) explicit• even in integrated learning environments (LMS)

•many tools (CMS, forum, blogs, etc.), but separated on tool and content level

• especially not in distributed environments•e.g., lecture recording & discussion forum

• Why is it a problem?•many media breaks•missing awareness of existing learning resources•preservation and (re-)access of parts of a learning ecosystem is difficult

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Implications of the Web for learning

• The WorldWideWeb was a proposal for a Hypertext project• Change from linear to non-linear; from a chain of knowledge to a web of knowledge

• The early Hypertext designs of the "founding trinitiy of hypertext" (Bush, Engelbart, Nelson) already had a focus on learning:• Bush's Memory Extender: "A Memex is a device in which an individual store all his books, records, and communications, and which is mechanized so that it may be consulted with exceeding speed and flexibility. It is an enlarged supplement to his memory" [Bush1945]

• Nelson's ELF: "Let suggest that such a system [..] could have great potential for education

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http://www.w3.org/Proposal.htmlhttp://www.w3.org/History/1989/proposal.html

http://www.w3.org/Proposal.html




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Links & Learning

•"A fundamental condition for learning is the engagement with information: making connections, setting interrelations, and meaningful arranging of information. Doing so, information can be better remembered if they are associated, and connections can be created with existing knowledge." [Iske2002]

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Iske, S. (2002). Vernetztes Wissen : Hypertext-‐Strategien im Internet. Wilhelm Bertelsmann Verlag.

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Web & Semantic Web

•The Web allows making connections•The Semantic Web add semantic information• Linked Data provides best practices to publish and connect data across the Web

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So what's missing then?! :-‐)

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Making fine granular connections

•What we need are concepts that help us to make more fine-granular connections between (aggregated) resources

•Using URIs not only to identify things, but also selections and aggregations of things

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contradicts

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Related Work

•Temporal fragments•W3C Media Fragments (temporal parts of audio-visual materials on the Web)

•Textual selections•XPath

•W3C POWDER (Protocol for Web Description Resources)•Provide descriptions of (group of) online resources

•Data repositories•SQL•SPARQL

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-‐ specialized to specific media type-‐ XPath: No names (URIs) for things

-‐ don't use URIs for results-‐ cannot be dereferenced

Grouping of URIs but no selec7ons of parts

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Approach: Linked Data Selectors Ontology

•Purpose: Describing selections of dereferenceable fragments of Web resources and their representations

•LDS Classes•Selector•Selector Set•SelectionRepresentation

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LDS: Selector class

• A Selector • is a fragment of exactly 1 Thing•has representation min 0 Selection Representation•has subselector max 1 Selector

•Selector subclasses:•Spatial

• for spatial selections, especially at 2D layers•Temporal

• describing selections of time or time-based media•Declarative

• describing selections with domain specific languages (SQL, SPARQL, XPath, ...)

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LDS: Spatial Selector

• has Geometric Shape Description exactly 1 Thing• A description of a geometric selection, e.g. with a 2D shape

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Geometrical shape excursus

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• Formal modeling not that easy, e.g.,• how to formally describe that a

parallelogram has two pairs of opposite angles that have equal measures?

Rectangle(?r), height(?r, ?h), width(?r, ?w), equal(?h, ?w) -> Square(?r)

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Declarative Selectors

•has Declaration• could be a XPath description or SQL query

•Example for a history lesson:•all US presidents that are/were members of the Democratic Part

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select ?president where {?president a dbpedia-owl:President .?president dbpprop:party <http://dbpedia.org/resource/Democratic_Party_(United_States)> .

}

http://dbpedia.org/resource/Democratic_Party_(United_States)




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Temporal selectors

• A selector for time-based media like audio and video• has Temporal Description exactly 1 Thing• Could be used in combination with time-based descriptions, like Time Ontology for Synchronous Media or W3C OWL-Time

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Excursus: Time Ontology for Synchronous Media

•TimeUnit (Defines units of time like minutes, seconds, hours. Time units can be derived from a base unit, e.g. minutes can be derived from seconds. DerivedTimeUnits have a scaling number.)•BaseTimeUnit•DerivedTimeUnit

•TimeEntity•TimeInstant •TimeInterval

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conversion between 7me units with SWRL:TimeInstant(?instant), hasScalingNumber(millisecond, ?scaling), inSeconds(?instant, ?sec), multiply(?result, ?sec, ?scaling) -> inMilliSeconds(?instant, ?result)

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Selector set

•A Selector Set • is used for grouping selectors in order to speak about more than one selector• Usually, a set of selectors consists of 2 or more Selectors, but may be also refer to a Resource Set for grouping resources (W3C POWDER)• has Selector some Thing or has Selector min 2 Selector

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LDS: SelectionRepresentation class

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Types of representa7on

A selec7on has a media resource that represents the selec7on result

media resources can be described by, e.g., using the W3C Media Resources vocabulary

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Use by example

• selection of a video snippet

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timeinterval

selectionbegin

hasStartTime

timeIntervalSelection

cutvideopresentation

hasRepresentationTimeInterval

has individual

hasTemporalDescription

selectionend

IntervalSelector has individual

videocut

hasMediaResourceVideoTrack

has individual

VideoRepresentation

has individual

hasEndTime

longvideo

fragmentOf

has individual

"23.0"

"http://cutvideo.mp4"

inSeconds

"83.0"

inSeconds

locator

"http://video.mp4"

locator

Interval Selection

Selection source

Selection representation

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Use by example 2: Linking slides

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Höver, K. M., Hartle, M., & Rößling, G. (2011). A collaborative linked learning space. In ITiCSE '11: Proceedings of the 16th annual joint conference on innovation and technology in computer science education (pp. 380-380). ACM. doi:10.1145/1999747.1999893

Höver, K. M., Hartle, M., Rößling, G., & Mühlhäuser, M. (2011). Evaluating how students would use a collaborative linked learning space. In ITiCSE '11: Proceedings of the 16th annual joint conference on innovation and technology in computer science education (pp. 88-92). ACM. doi:10.1145/1999747.1999774

Höver, K. M., von Bachhaus, G., Hartle, M., & Mühlhäuser, M. (2012). DLH/CLLS: An open, extensible system design for prosuming lecture recordings and integrating multimedia learning ecosystems. In IEEE international symposium on multimedia (pp. 477-482). doi:10.1109/ISM.2012.97

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Excursus: Collaborative Linked Learning Space

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CLLS

Lecture Recordings described with RDF(including log data

and augmentations)

Automatic indexing of

slides

Automatic linking of slides with related

resources (DBpedia, Wikipedia, OU Repository..)

FOAF for users

Geolocation of users to find near learning

partners

Integration of learning communities (discussion forums)

& live updatingSPARQL

A keyword

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• link a set of slides with a paragraph of a website

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#303slides

:hasDeclarationSparqlSelector

has individual

:fragmentOf

Sparql Endpoint"SELECT ?slide WHERE { ?slide a #Slide . ?slide dc:subject '303 URI'.}"

#booksection

#explains

XPathSelector

has individual:hasDeclaration :fragmentOf

"http://linkeddatabook.com/editions/1.0/""/HTML/BODY/P[59]"

Slides paragraph

#parrepresentation

:hasRepresentationTextRepresentation

has individual

#textresource

:hasMediaResource

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Use by example 3: Linking slides with OpenUniversity VideoPodcasts

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#303slides

hasDeclarationSparqlSelector

has individual

fragmentOf

Sparql Endpoint"SELECT ?slide WHERE { ?slide a #Slide . ?slide dc:subject '303 URI'.}"

#podcasts#explains

SparqlSelector

has individual

hasDeclarationfragmentOf

Sparql Endpoint

"SELECT ?c WHERE { {?c a <http://data.open.ac.uk/podcast/ontology/VideoPodcast>} }

FILTER regex(str(?desc), "303 uri", "i" )}}"

Slides Video Podcast

•Case 1: Client is able to process LDS documents

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Making LDS dereferenceable

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Client Server Ahttp://serverA.de/LDSdocument.ttl

HTTP GET requestAccept: application/lds

HTTP OK

Process LDS document

Present process result

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Making LDS dereferenceable

•Case 2: Client is able to process LDS documents

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Client Server Ahttp://serverA.de/LDSdocument.ttlHTTP GET request

Accept: image/png

HTTP 303 See otherhttp://serverB.org/figure.png

if there is an image representation of the selection, redirect to this representation

HTTP GET requesthttp://serverB.org/figure.png

HTTP 200 OK

Server Bhttp://serverB.org/figure.png

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LDS meeting LD principles

1. Use URIs as names for things- Selections can be referenced by URIs

2. Use HTTP URIs, so that people can look up those names- LDS URIs can be dereferenced using, e.g., 303 URIs

3. When someone looks up a URI, provide useful information, using the standards (RDF, SPARQL)- LDS URIs provide information about the selection type and source

4. Include links to other URIs, so that they can discover more things- LDS documents can include links to the original source of a selection as well as several representations of a selection

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Summary & future work

•We have suggested an ontology for giving selections of things individual names (URIs)• description of selections (include grouping and chaining)• description of selection results

•Helping both educators and students to link things that are related

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•Future work:• automatic creation of representations• integration of authentication, especially for

declarative selectors (Omnivoke Authentication ontology)

• integration of LDS with W3C POWDER?• user studies; visualization• describing the dereferencing process of LDS

(content negotiation, 303 URIs)

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Thank you for listening

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Ques8ons? Sugges8ons for improvement? :-‐)

linked data selectors

Technology