Yovisto is a new video search engine for educational videos and e-lectures. yovisto provides a social tagging function. You can sign up at yovisto and maintain your own online lecture collections, maintain an own user profile, make friends, choose your favorite video lecture, share lecture recordings and (!) you can tag videos.

Description of yovisto ontology

Abstract

Linked Open Data has become one of the driving forces for the emerging Semantic Web, which enables interlinking and integrating former proprietary data to the global linked data by using RDF as a standard data format. We have published the database of yovisto.com in RDF and made it accessible via SPARQL.

This page specifies the yovisto ontology and shows some examples on how to use this ontology with our SPARQL endpoint.

OWL-DL Ontology: http://www.yovisto.com/ontology/0.9/index.owl

SPARQL-Endpoint: http://sparql.yovisto.com/


Further information:

Table of Content

  1. Overview
  2. Namespaces
  3. Classes
  4. Usage

Overview

The yovisto ontology

Namespaces

 
The following namespaces are used:
 
Prefix URI Comment
yo http://www.yovisto.com/ontology/0.9/ the yovisto base ontology
foaf http://xmlns.com/foaf/0.1/ the friend of a friend namespace
owl http://www.w3.org/2002/07/owl# the Web Ontology Language
dc http://purl.org/dc/elements/1.1/ Dublin Core Metadata Element Set, Version 1.1 - the Dublin Core ontology
dcterms http://purl.org/dc/terms/ DCMI Metadata Terms - the Dublin Core ontology with element refinements
rdf http://www.w3.org/1999/02/22-rdf-syntax-ns# the RDF base namespace
rdfs http://www.w3.org/2000/01/rdf-schema# the RDFSchema namespace
tag http://www.holygoat.co.uk/owl/redwood/0.1/tags/ the tag/tagging ontology
mpeg7 http://rhizomik.net/ontologies/2005/03/Mpeg7-2001.owl# the mpeg7 ontology
skos http://www.w3.org/2008/05/skos# the Simple Knowledge Organization System,
a common data model for sharing and linking knowledge organization systems

Classes

 
Category:

Every video collection usually belongs to a category, as e.g., Computer Science or Physics. You can find an overview on yovisto's categories here.

Constraint Property
exactly 1 dc:identifier
dc:title
maximal 1 skos:related
 
Collection:

A collection is a series of videos (videofiles) or a Podcast consisting of episodes. A collection also represents a lecture series consisting of several classes.

Collection is a part of Category.

Constraint Property
exactly 1 dc:identifier
dc:title
dc:creator all values from Organization
maximal 1 dc:subject all values from Category
dc:coverage
 
Video

A video is a digital asset, e.g., a lecture recording.

Constraint Property
exactly 1 dc:identifier
dc:title
dcterms:extent
dcterms:isPartOf only Collection
maximal 1 dc:subject all values from Category
dc:coverage
dc:description
dc:format
dc:language
dcterms:alternative
minimal 1 dc:contributer all values from Speaker
minimal 0 mpeg7:MediaTime
 
VideoSegment:

A videosegement is a part of a video. Videosegments are examined with scene detection algorithms specialized on lecture recordings automatically.

VideoSegment is a part of exactly 1 Video.

Constraint Property
exactly 1 dcterms:isPartOf only Video
mpeg7:MediaTime
maximal 1 dc:description
dc:title
 
MediaTimeType:

The MediaTimeType specifies any time intervall in a video. Usually, a MediaTimeType has a start time point and a duration. MediaTimeType is used to specify the time reference of video segments and tags in a certain video. See also: mpeg-7 ontology

MediaTimeType is a part of the mpeg7 ontology.

Constraint Property
Multiple mpeg7:MediaTimePoint
mpeg7:duration
tag:tag all values from Tagging
 
Tagging:

Tagging describes the process when a user tags a video. See also: tag ontology

Tagging is a part of the tag ontology.

Constraint Property
Multiple tag:associatedTag
exactly 1 tag:taggedBy all values from User
 
Tag:

See also: tag ontology

Tag is a part of the tag ontology.

Constraint Property
exactly 1 tag:name
rdfs:seeAlso
 
Speaker:

A speaker is a contributing person in the video, which is usually visible or audible.

Speaker is a subclass of foaf:Person.

Constraint Property
exactly 1 rdfs:subClassOf foaf:Person
dc:identifier
foaf:surname
 
Organization:

An organization is an university or institute where the video was created.

Organization is a subclass of foaf:Organization.

Constraint Property
exactly 1 rdfs:subClassOf foaf:Organization
dc:identifier
foaf:name
maximal 1 foaf:homepage
foaf:logo
 
User:

The user stands for a registered yovisto account.

User is a subclass of foaf:OnlineAccount.

Constraint Property
exactly 1 rdfs:subClassOf foaf:OnlineAccount
foaf:accountName

Usage Examples

 
Hints:

 
The classes Video and VideoSegment are linked over the property mpeg7:MediaTime to mp7:MediaTimeType
which has two properties: mp7:MediaTimePoint and mp7:duration.

Because of the allocation of tags just for a special segment in one video these segments are distinguished with these information.
So the mp7:MediaTimePoint tags the startpoint of this segment and the mp7:duration tags the duration
how long the segment is on and the tag is valid in one video.

Although Video keeps the property dcterms:extent which only means the duration of the whole video. Don't confuse it with mp7:duration!
 
Examples:

 
The following example shows a SPARQL query which delivers the 10 most assigned tags in yovisto:
				
PREFIX tag: <http://www.holygoat.co.uk/owl/redwood/0.1/tags/>
PREFIX mpeg7: <http://rhizomik.net/ontologies/2005/03/Mpeg7-2001.owl#>

SELECT ?name, COUNT(*) FROM <http://www.yovisto.com>
WHERE {
  ?video mpeg7:MediaTime ?mediaTimeType .
  ?mediaTimeType tag:tag ?tagging .
  ?tagging tag:associatedTag ?tag .
  ?tag tag:name ?name .
}
GROUP BY ?name
ORDER BY DESC 2
LIMIT 10
				 		
				
[execute query]
 
And similar to the query above you can search for all videos which are tagged with "ipv6":
				
PREFIX tag: <http://www.holygoat.co.uk/owl/redwood/0.1/tags/>
PREFIX mpeg7: <http://rhizomik.net/ontologies/2005/03/Mpeg7-2001.owl#>

SELECT ?video FROM <http://www.yovisto.com>
WHERE {
  ?video mpeg7:MediaTime ?mediaTimeType .
  ?mediaTimeType tag:tag ?tagging .
  ?tagging tag:associatedTag ?tag .
  ?tag tag:name "ipv6" .
}
				 		
				
[execute query]
 
This query delivers all videos and their titles which belong to the category "Biology":
				
PREFIX dc: <http://purl.org/dc/elements/1.1/>

SELECT ?video, ?title FROM <http://www.yovisto.com>
WHERE {
  ?video dc:subject ?category ;
    dc:title ?title .
  ?category dc:title "Biology" .
}
				 		
				
[execute query]

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