This document recommends an approach for exposing IEEE LOM [[IEEE-LOM]], a metadata standard for educational contents, as Linked Data. The first version of this document is available at here. It is intended as a bridge for linkage of educational metadata into Linked Open Data (LOD). This recommendation aims to describe a mapping of IEEE LOM elements to RDF based on Linked Data principles [[LDSO]]. It also presents VoID recommendation for expressing repository data as a dataset along with a practical example.

Audience

This document is mainly addressed to the repositories and the ODS partners, especially to those directly involved in the exposing their content and collection as Linked Data. It is also of particular interest to the repository managers, as this document contains instructions to express the educational resource as RDF. The owners of digital collections of educational resources that aim at exposing the metadata of their resources openly on the Web, can be another target of this document as well.

Introduction

IEEE LOM [[IEEE-LOM]], as a popular standard for describing educational contents, promotes their reusability, discoverability and interoperability. Linked Data approach, in other side, makes eLearning applications an open exposure of metadata in which searching and navigating are possible, not only in centralized metadata stores, but also across the external repositories [[OREDULD]].
This draft provides recommendations to expose IEEE LOM as Linked Data. IEEE LOM elements discussed here, are based on the final version of IEEE 1484.12.1-2002 Standard for Learning Object Metadata (LOM) [[IEEE-LOM]] , which defines a structure for interoperable descriptions for learning objects. We describe how IEEE LOM elements can be expressed educational metadata as Linked Data based on Linked Data principles [[LDSO]] and complying with common Linked Data patterns [[LDPatt]].
This approach covers the following steps :
  • URI design recommendation of elearning objects
  • RDF binding of LOM elements and their date types
  • Experimental implementation of LOM elements to RDF [[RDF-PRIMER]]
  • Exposing repository metadata using VoID
  • Recommendations on linking to other datasets
  • Document conventions

    All examples in this document are written in the Turtle format [[TURTLE]] to represent RDF with the following namespaces:
        @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
        @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
        @prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
        @prefix dcterms: <http://purl.org/dc/terms/> .
        @prefix xdt: <http://www.w3.org/2005/xpath-datatypes> .
        @prefix cc: <http://creativecommons.org/ns#> .
        @prefix vcard: <http://www.w3.org/2001/vcard-rdf/3.0#>.
        @prefix lom:<http://ltsc.ieee.org/rdf/lomv1p0/lom#>.
        @prefix lomvoc: <http://ltsc.ieee.org/rdf/lomv1p0/vocabulary#>.
        @prefix lomterms: <http://ltsc.ieee.org/rdf/lomv1p0/terms#>.
        @prefix foaf: <http://xmlns.com/foaf/0.1/> .
        
    In the appendix, there is a LOM metadata example harvested from a repository by Organic.Edunet [[OrgEdunet]]. This example is used throughout this document as a sample. Some elements have been added to the example so that covers all the LOM elements as well. The identifier of this learning resource is simplified as follows:
        
        http://www.youtube.com/v/BebNsezt6r0?version=3&f=videos&c=YouTubeHarvester&app=youtube_gdata 
        is simplified as:
        http://Youtube.com/v/BebNsezt6r0
        

    URI design

    Using strings or number conforming to a formal identification system [[DC11]] is considered to be best practice. In IEEE LOM, identifiers are defined as "globally unique label that identifies a learning object" and are to be provided in:

    In a general case, when exposing learning object metadata, the dereferenceable URIs that deliver RDF descriptions are actually identifying metadata records and not the actual resources. In consequence, the identification in Element 3.1. is represented as the dereferenceable URI from which the RDF metadata is exposed, and there is no need to expose it again in the RDF representation. The identifier of the actual resource can then be exposed as is in the metadata record, following the guidelines described below:
                <Repository URI> /  <meta-Metadata ID>
           

    Note: In the case that meta-Metadata or repositories identifiers are not available, another possibilities could be using the combinition of repository name space and file name as follows:
                <Repository name space>_<metadata file name>
           

    In the case of the Relation element, the recommended practice is using the dereferenceable URI of the resource pointed by this one, if available, in the form of a RDF link. In summary and based on above discussion, if learning objects are considered as natural hierarchy, patterned URI can be assigned to them [[LDPatt]].

    Case study:
    In the Organic.Edunet repository, each learning object metadata has an identity or Primary Key. URI of LOM conforms to the following pattern:
           <Repository URI>/resource/identifier/ metaMetadata_PrimaryKey
           
    Repository URI in the above pattern is URI of the current repository (or harvester, etc). For instance, in our example, it is indicated as:
           http://data.organic-edunet.eu/resource/identifier/1454
           
    If the identifiers are not available, another posibilities could be using the actual LOM file name, as follows:
           http://data.organic-edunet.eu/ont/lom/OrganicEdunet01
           
    Some cases that should be discussed in learning object identifications are the following:

    Identifying one copy from several with different properties

    If there exist copies of a same learning object in different repositories with different properties, e.g. different access rights, it is necessary to distinguish between these different copies. This is achieved by having one metadata record for each copy of the object. In general, the same resource can be legitimately described by different metadata records in the same or in dissimilar collections, for identifying as well as describing the same resource from different perspective (e.g. for different educational usages).

    Identification of versions

    Learning objects may contain version metadata. This should indicate the version level and the unique identifier of the immediate parent object ("is version of"). It modifies the metadata of the parent to show that it is the parent of a new child ("has version") and provide the unique general.identifier of the child. In any case, this is achieved by relating different records.

    Binding simple and structured IEEE LOM elements

    Two types of LOM elements exist: simple and structured. Following sections explain how each type is exposed as RDF.

    Simple element binding:

    Simple LOM elements do not contain other LOM data elements. For RDF binding of simple element, the RDF triple of element is represented in a same place as subject, predicate and object in which object is a literal. The following example, shows Technical.Format of a learning object, as a simple element:
            <technical>
          	<format>
                  "application/x-shockwave-flash"
          	</format>
            </technical>
            
    Which is represented in Turtle as follows:
            <http://Youtube.com/v/BebNsezt6r0> dcterms:format "application/x-shockwave-flash".
            

    Structured element binding:

    Regardless simple elements, an structured (or aggregate) element contains other LOM elements (either simple or structured elements). For binding of structured elements, the object is not represented in the same tag, but is pointed to another node, which means an intermediate node of RDF is created by this way. There exist various options of how to expose structured elements as RDF:

    Structured element with multiplicity 1

    For exposing structured elements with multiplicity 1, for instance title, one of the following options can be used:
               <title>
                 <string language="el">Τι είναι βιολογικό.</string>
                 <string language="de">Was ist biologisch.</string>
                 <string language="en">What is organic.</string>
               </title>
              

    Option 1: using repeated properties
       <http://Youtube.com/v/BebNsezt6r0> dcterms:title "What is organic" @en, "Τι είναι βιολογικό" @el, "Was ist biologisch" @de.
       

    Option 2: using intermediate node
       <http://Youtube.com/v/BebNsezt6r0> dcterms:title _:bnode864405440.
          _:bnode864405440 rdf:value "What is organic" @en,
                                  	 "Τι είναι βιολογικό" @el,
                                	 "Was ist biologisch" @de.
       

    Structured elements with multiplicity "Many"

    Keyword, as a structured element of IEEE LOM, is expressed in XML as follows:
            <general>
              <keyword>
                    <string language="en"> certification </string>
                    <string language="el"> πιστοποίηση </string>
                    <string language="de"> Zertifizierung </string>
              </keyword>
              <keyword>
                    <string language="en">conventional farming</string>
                    <string language="el">συμβατική γεωργία</string>
                    <string language="de">konventionelle Landwirtschaft</string>
              </keyword>
              <keyword>
                    <string language="en">organic farming</string>
                    <string language="el">βιολογική γεωργία</string>
                    <string language="de">biologische Landwirtschaft</string>
              </keyword>
            </general>
            

    Intermediate node is recommended for representing those structured elements that have many values.
            <http://Youtube.com/v/BebNsezt6r0> lom:keyword _:node1,_:node2,_:node3.
               _:node1 rdf:value "certification" @en, "πιστοποίηση" @el, "Zertifizierung" @de.
               _:node2 rdf:value "conventional farming" @en, "συμβατική γεωργία" @el, "konventionelle Landwirtschaft" @de.
               _:node3 rdf:value "organic farming" @en, "βιολογική γεωργία" @el, "biologische Landwirtschaft" @de.
            

    Structured elements with multiplicity "Many" and ordered

    RDF containers [[LDPatt]], are another options specially for those cases that order of representing elements is important:
               <classification>
                  <keyword>
                      <string language="en">Organic<string>
                  </keyword>
                  <keyword>
                      <string language="en">Farming<string>
                  </keyword>
              </classification>
             
    Which are expressed by RDF containers as follows:
             <http://Youtube.com/v/BebNsezt6r0> lom:classificationKeyword _:node1.
                 _:node1 a rdf:Seq;
                 rdf:_1 "Organic" @en.
                 rdf:_2 "Farming" @en.
            
    Note: In the Organic.Edunet LD representation, for structured elements with multiplicity 1, option 1 of section 4.2.1 and for structured elements with multiplicity "many" section 4.2.2 is expressed.

    Data type mapping

    CharacterString

    Each simple element in literal format is represented as following:

            <http://Youtube.com/v/BebNsezt6r0> dcterms:format "application/x-shockwave-flash".
            

    LangString

    Many elements in IEEE LOM standard are literal and translations or may have multiple literals that are related semantically. Version of a learning object, for instance, may be represented by more than one language. Here, for RDF binding of this element, xml:lang can be used as an attribute for the element(lom:version) for representing the language. This attribute consists of language code conforming to RFC1766 [[RFC1766]].
              <http://Youtube.com/v/BebNsezt6r0> lom:version _:node1
              _:node1 rdf:value "It is not available" @en, "no está disponible" @es.
            
    RDF offers several modeling options for defining collections of resources [[LDPatt]]. Formally these are the RDF Containers (Sequence, Bag, and Alternates) and the RDF Collections (List). For this purpose and the cases that ordering are essential, RDF Sequence (rdf:Seq) is used.
    Note: For more information about the implementation of LangString see Section 4.2

    DateTime

    The International Standard for representation of dates and times is ISO 8601 [[ISO8601]] that describes a large number of date/time formats. The LOM standard defines at least the four digits for year, two digits for month and two-digit day of month. For representing the time, the standard defines two digits of hour, two digits of minute, two digits of second and one or more digits representing a decimal fraction of a second. Times are expressed in UTC (Coordinated Universal Time), with a special UTC designator ("Z"). For example, 1994-11-05T08:15:30-05:00 corresponds to November 5, 1994, 8:15:30 am, US Eastern Standard Time and 1994-11-05T13:15:30Z corresponds to the same instant. The LOM elements that contain Data/Time values can be written in following format:
        <http://Youtube.com/v/BebNsezt6r0> lom:dateTimeValue  "2011-05-17T05:53:31.00Z"
             ^^<http://www.w3.org/2001/XMLSchema#dateTime>.
         
    Note: A date/time value can be described as a description in IEEE LOM Standard such as ("en","circa 1300 BCE"). In this case the element is represented as LangString.
        <http://Youtube.com/v/BebNsezt6r0> lom:dateTimeValue "2011-05-17T05:53:31.00Z"; 
    	lom:dateTimeDescription  "Date of publishing the learning object".
             
         

    Duration

    If an element contains duration value, the date type of the element is indicated such as follows:
         <http://Youtube.com/v/BebNsezt6r0> lom:technicalDuration  "PT0.269S"
             ^^<http://www.w3.org/2005/xpath-datatypes#dayTimeDuration>.
         
    In the above example, duration ("PT0.269S") shows that technical duration of the learning object is 269 seconds based on ISO8601, although this kind of format is not human readable.
    Note: A duration value can be described as a description in IEEE LOM Standard [[IEEE-LOM]] such as ("en", "Fall Semester 1999"). In this case the element is also represented as LangString.

    Boolean

    If an element contains Boolean value (True or False), the date type of the element is indicated as follows:
        <http://Youtube.com/v/BebNsezt6r0> lom:cost false ^^<http://www.w3.org/2001/XMLSchema#boolean>.
        

    VCARD

    vCard as a standard for electronic business cards, is used for describing of entities in RDF binding. A resource in RDF uses vCard properties such as vCard:FN, vCard:ORG and vCard:Email. The value of entity of contribute element, In following example, in Life Cycle category is a vCard record.
            BEGIN:VCARD
            FN:Hannes Ebner
            EMAIL;TYPE=INTERNET:hebner@kth.se
            ORG:http://www.kth.se
            N:Ebner;Hannes
            VERSION:3.0
            END:VCARD
         
    This item can be represented as follows:
            <http://Youtube.com/v/BebNsezt6r0> contributionEntity
            "BEGIN:VCARDFN:HannesEbnerEMAIL;TYPE=INTERNET:hebner@kth.se;ORG:http://www.kth.seN:Ebner;HannesVERSION:3.0;END:VCARD"
        
    For mapping vCard to RDF, following representation is recommended:
            <http://Youtube.com/v/BebNsezt6r0> contributionEntity _:bnode1247.
               _:bnode1247 vcard:FN "HannesEbner".
               _:bnode1247 vcard:N "Ebner;Hannes".
               _:bnode1247 vcard:EMAIL _:bnode1248.
               _:bnode1247 vcard:ORG "http://www.kth.se".
               _:bnode1247 vcard:VERSION 3.0.
    
            _:bnode1248
                   rdf:value "hebner@kth.se";
                   rdf:type "http://www.w3.org/2001/vcard-rdf/3.0#internet".
         

    Undefined data type

    Date type of IEEE LOM Elements can be expressed explicitly in RDF. xsd:dateTime, for example, is specified for datetime format and rdfs:parseType or rdf:Literal for the string data types. For those elements that are not included any specific date type in IEEE LOM , xsd:anyType is recommended [[XMLSCHEMA-0]].

    Recommended use of existing vocabularies/formats

    There are some vocabularies used to describe people, places, things and locations include using terms from Dublin Core [[DC11]], which describes metadata about published works, or Friend-of-a-Friend (FOAF) [[FOAF]], used to describe people and their relationship to other people, vCard for electronic business cards or GeoNames a geographical database covers all countries and over ten million geographical names.
    In this document, use of the URI and authoritative vocabularies that data publishers are able to publish information more quickly, is presumed. For example:

    -To model simple data, are used RDF, RDFS and custom vocabularies
    -To name things, are used rdfs:label and foaf:name
    -To describe people, are used FOAF and vCard
    -To describe Web pages and other publications, are used dc:creator and dc:description
    -To describe addresses, is used vCard

    Following table shows vocabulary/format mapping of some LOM elements.
    LOM element used vocabulary/format
    Contribute.Entity vCard
    CharacterString rdf:value
    General.Description dcterms:description
    General.Language dcterms:language
    General.identifier.entry dcterms:identifier
    General.Title dcterms:title
    General.Coverage dcterms:coverage
    Technical.Format dcterms:format
    Right.Description dcterms:rights

    Note: All the URIs for LOM vocabulary terms shown in Appendix D.

    IEEE LOM Element Mapping

    Following Table illustrates instructions to map the LOM elements to Linked Data format. The mapping of elements with same data type, has been ignored in the Table.

    LOM element kind Mapping Example Details
    General.Identifier Expose Catalog as String
    Link Entry using dcterms:identifier
    <http://Youtube.com/v/BebNsezt6r0> dcterms:identifier "http://..." Appendix B
    CharacterString Elements subject predicate object <http://Youtube.com/v/BebNsezt6r0> lom:identifierCatalog "URI" Section 6-1
    Elements with VCARD description Use separated VCARD elements <http://Youtube.com/v/BebNsezt6r0> lom:lifeCycleContribution _:bnode1247.
    _:bnode1247 vcard:FN "HannesEbner".
    Section 6-6
    Meta-Metadata Identifier Entry Repository URI/identifier/Metadata URI http://Youtube.com/v/BebNsezt6r0/identifier/
    http://agcrops.osu.edu/
    Section 6-1
    LangString with language tag String @ Language Tag <http://Youtube.com/v/BebNsezt6r0> dcterms:title
    "Agronomic crops network" @en;
    Section 6-2
    DateTime or Duration Map to string/LangString "16th century France" DateTime may be appeared in both formats (DateTime and String)
    LangString elements with multiplicity one Map to string [@Language Code] <http://Youtube.com/v/BebNsezt6r0> dcterms:title "Agronomic crops network" @en; "Red de cultivos agronómicos" @es Section 6-2
    LangString with multiplicity many Use intermediate node or
    use RDF containers
    <http://Youtube.com/v/BebNsezt6r0> lom:keyword _:bnode864405440.
    _:bnode864405440 rdf:value "certification"@en,"πιστοποίηση"@el, "Zertifizierung"@de.
    Section 4-2
    Rights Description Link to Creative Common <http://Youtube.com/v/BebNsezt6r0> dcterms:rights <http://creativecommons.org/licenses/by-nc-nd/3.0/> -
    Contribute.Entity Use vCard or use FOAF for people <foaf:Person> <foaf:name>Hannes Ebner</foaf:name> </foaf:Person> -
    Metadata Schema Use schema URI <http://ltsc.ieee.org/xsd/lomv1.0/lom.xsd> -
    Annotation Use intermediate node for each annotated group <http://Youtube.com/v/BebNsezt6r0> lom:annotation _:bnode1,_:bnode2,_:bnode3.
    _:bnode1 lom:annotationEntity _:bnode4;
    lom:annotationDate 2012-11-08T13:13:30.0;
    lom:annotationDescription _:bnode5.
    _:bnode4 ...{is implemented as VCARD}
    _:bnode5 ...{is implemented as LangString}
    -

    Classification mapping

    IEEE LOM standard represents the classification of a learning object in classification category in which each classification includes purpose and taxonpath. Taxonpath represents the structure of taxonomy. At the top level is a list of broad terms. Under each term is a list of terms that refine each of the broad terms which may be another list. Each e-learning object metadata includes several taxonpath and in each taxonpath exists several taxon. Hence, for mapping of classification category, following RDF mapping is recommended:
             <http://Youtube.com/v/BebNsezt6r0> lom:classification _:classification1.
    
             _:classification1    lom:classificationPurpose lomvoc:discipline;
                                  lom:classificationDescription "This classification provides
                                  many examples of Organic Principles and Ontologies. "@en;
                                  lom:classificationKeyword _:keyword1,_:keyword2;
                                  lom:taxonPath _:taxonpath1, _:taxonpath2.
             ----------------------------------------------------------
             _:taxonpath1 lom:taxonpathSource  "NACE Codes of Economic Activity "@en;
                          lom:classificationTaxon    _:taxon1.
             _:taxon1 lom:taxonId   "NACE Codes of Economic Activity";
                      lom:taxonEntry  "ΔΗΜΟΣΙΑ ΔΙΟΙΚΗΣΗ ΚΑΙ ΑΜΥΝΑ, ΥΠΟΧΡΕΩΤΙΚΗ ΚΟΙΝΩΝΙΚΗ ΑΣΦΑΛΙΣΗ" @gr.
             ----------------------------------------------------------
             _:taxonpath2 lom:taxonpathSource  "Organic.Edunet Ontology "@en;
                          lom:classificationTaxon   _:taxon1, _:taxon2.
    
             _:taxon1 lom:taxonId   "http://www.cc.uah.es/ie/ont/OE-Predicates#Explains";
                      lom:taxonEntry     "http://www.cc.uah.es/ie/ont/OE-OAAE#OrganicPrinciple".
             _:taxon2 lom:taxonId   "http://www.cc.uah.es/ie/ont/OE-Predicates#ProvidesDataOn";
                      lom:taxonEntry     "http://www.cc.uah.es/ie/ont/OE-OAAE#PlantProductionIssue".
             ----------------------------------------------------------
             _:keyword1 rdf:value "Organic "@en.
             _:keyword2 rdf:value "Farming "@en.
          
    RDF containers (RDF:Seq) can be also used for describing the Classification Keyword as we discussed in section 4.2.3 .

    Relation mapping

    The Relation category groups features that define the relationship between the learning object and other related learning objects, if any. Same as the classification mapping section, e-learning resource may include different relations and they are implemented as different intermediate nodes.
                  <http://Youtube.com/v/BebNsezt6r0> lom:relation _:relation1.
                   ----------------------------------------------------------
                  _:relation1 lom:relationKind  dcterms:isPartOf;
                              lom:identifier _:resource1,_:resource2;
                              lom:relatedResourceDescription _:resourceDescription1.
                    ----------------------------------------------------------
                  _:resource1 lom:identifierCatalog "URI";
                              dcterms:identifier "http://smilingvines.com/OrganicvsConventional.pdf".
                  _:resource2 lom:identifierCatalog "URI";
                              dcterms:identifier "http://smilingvines.com/OrganicFarming.pdf".
                   ----------------------------------------------------------
                   _:resourceDescription1 dcterms:description "This context of this learning object is
                   based on a research mentioned partially in these two PDF documents. "@en.
             

    Exposing repository metadata using VoID

    VoID (Vocabulary for Interlinked Data ), as a bridge between the data publishers and consumers, expresses general metadata based on Dublin Core and other vocabularies such as FOAF and SKOS [[VOID]]. It covers different kinds of metadata (access, structural, and links between datasets) based on RDF Schema vocabulary [[RDF-SCHEMA]]. VoID served for describing repositories that publish their e-Learning objects as Linked Data format. Repositories compliant with Linked Data principles [[LDSO]] could be considered as datasets and described by VoID.
    Note: In this section, when we mention a repository dataset, we point those repositories expose their e-Learning objects as Linked Data.

    VoiD Definition

    Four areas of VoiD are defined for e-learning repositories as follows:
    The most important concept of VoID, is a dataset which is set of RDF triples that are published and modelled as an instance of the void:Dataset class.
     For instance,Organic.Edunet is expressed as a VoID dataset:
                    :OrganicEdunet a void:Dataset
                
    Following Table declares the different void elements that describe a repository as a dataset. In this tables, following columns are defined:
     Field: states a void element
     Description: brief description of a void element
     Vocabulary: describes the vocabulary of the field
     Obligation: describes which fields are mandatory/optional or recommended
     Example: an example of the field
    All other void elements for describing datasets are available at [[VOID]].

    Field Description Vocabulary Obligation Example
    void:Dataset Name of the repository dataset void Mandatory :OrganicEdunet a void:Dataset
    foaf:homepage Homepage of the repository dataset including information about the dataset foaf Mandatory :OrganicEdunet foaf:homepage <http://data.organic-edunet.eu>
    foaf:page Additional page of relevant information foaf Optional :OrganicEdunet foaf:page <portal.organic-edunet.eu>
    dcterms:title The name of the repository dataset Dublin Core Mandatory :OrganicEdunet dcterms:title "Organic Edunet"
    dcterms:description A textual description of the repository dataset Dublin Core Mandatory OrganicEdunet dcterms:description "a learning portal that provides access to digital learning resources on Organic Agriculture and Agroecology"
    dcterms:creator The creator entity of the repository dataset Dublin Core Recommended :OrganicEdunet dcterms:creator "European Union"
    dcterms:publisher The publisher entity of the repository dataset Dublin Core Recommended :OrganicEdunet dcterms:publisher "UAH"
    dcterms:contributer The contributor entity Dublin Core Recommended :OrganicEdunet dcterms:contributer "GRNET"
    dcterms:created Date of creation of the dataset Dublin Core Mandatory :OrganicEdunet dcterms:created "2012-09-15"
    dcterms:modified Date on which the repository dataset was changed Dublin Core Optional :OrganicEdunet dcterms:modified "2012-09-21"
    foaf:person Potential users of a repository dataset foaf/RDF Schema Optional :OrganicEdunet dcterms:publisher :Miguel;a foaf:person;
    rdfs:label "Miguel";foaf:mbox <mailto:miguel@orgnaic-edunet.eu>.
    dcterms:subject Category of the repository dataset Dublin Core Optional :OrganicEdunet dcterms:subject "http://dbpedia.org/page/Subsistence_agriculture"
    dcterms:license Terms under which the repository dataset can be used Dublin Core Mandatory :OrganicEdunet dcterms:license "http://creativecommons.org/licenses/by/"
    void:technicalFeature
    void:technicalFeature
    Format(s) of repository dataset that is available void Mandatory :OrganicEdunet void:technicalFeature "http://www.w3.org/TR/REC-rdf-syntax/"
    void:sparqlEndpoint A SPARQL endpoint of the repository dataset void Mandatory :OrganicEdunet void:sparqlEndpoint "portal.organic-edunet.eu/data/snorql"
    void:datadump RDF dump of the repository dataset void Optional :OrganicEdunet void:datadump "data.organic-edunet.eu/rdfdump.rdf"
    void:rootResource The root resource of the repository dataset void Optional :OrganicEdunet void:rootResource "portal.organic-edunet.eu"
    void:exampleResource An example entity that is representative for the entities described in a void:Dataset. void Recommended :OrganicEdunet void:exampleResource "http://data.organic-edunet.eu/page/identifier/1454"
    void:subset Description of parts of repository dataset void Optional :OrganicEdunet void:subset :Organic_Agriculture; void:subset :Organic_Agroecology.
    void:triples Total number of triples of repository dataset void Recommended :OrganicEdunet void:triples 10000
    void:classes Total number of classes of repository dataset void Optional :OrganicEdunet void:classes 10
    void:properties Total number of properties of dataset void Optional :OrganicEdunet void:properties 10
    void:target
    void:linkPredicate
    void:linkPredicate void Optional :DBpedia2DBLP a void:Linkset;void:target :OrganicEdunet;void:target :Dynalias; void:linkPredicate owl:sameAs.
    void:DatasetDescription A statement about the void file void Mandatory :DBpedia2DBLP a void:DatasetDescription "A VoiD Description of the Organic.Edunet Dataset"

    Deploying VoID descriptions

    For publishing VoID description alongside a dataset, a Turtle file named void.ttl is placed in the root directory of the dataset site, For example:
                http://data.Organic-Edunet.eu/void.ttl
            
    Appendix C declares description of organic.edunet dataset as VoID.

    Recommendations on linking to other datasets

    Linked Data as a global approach for interlinking data on the Web, allows educational material to be integrated and linkable so that make their e-learning resources more accessible, discoverable and reusable as well as unlocking educational information away from learners. DBpedia [[DBpedia]], as one of the most reused datasets and Linked Data version of Wikipedia, making it possible for anybody to link general information as well as extracting their relationship to other datasets. The advantages of this relationship is making one’s own public information linkable and usable for others as well as being able to enrich one’s own information by linking to others [[INTERLINK]]. Following table shows how some of IEEE LOM elements can be interlinked to other datasets as well. This recommendation table, includes all existing public datasets are available in Linked Open Data(LOD).

    LOM element description linking to
    General.Coverage When coverage refers to a location http://dbpedia.org/resource/{Location}
    DBpedia--> http://dbpedia.org/resource/{Location}
    GeoName--> http://sws.geonames.org/
    FreeBase--> http://freebase.com/api/service/search
    EuroStat--> http://eurostat.linked-statistics.org/
    WorldBank--> http://worldbank.270a.info/
    FAO Profile --> http://www.fao.org/countryprofiles
    General.Title When Title refers to a paper/publication/book/biography IEEE --> http://ieee.rkbexplorer.com
    Citeseer --> http://citeseer.rkbexplorer.com/
    ACM --> http://acm.rkbexplorer.com/
    Book --> http://openlibrary.org/
    British National Bibliography--> http://bnb.data.bl.uk/sparql
    DBLP --> http://dblp.l3s.de/d2r/
    or http://dblp.rkbexplorer.com
    ISWC, ESWC and WWW--> http://data.semanticweb.org
    {General,Meta-metadata,LifeCycle,Educational}.Language Refer to dbpedia http://dbpedia.org/resource/{language}_Language
    Technical.Format Link to dbpedia http://dbpedia.org/resource/{format}
    Requirement.OrComposite.Type/Name Link to dbpedia http://dbpedia.org/resource/{Requirement.OrComposite.Type/name}
    Educational.LearningResourceType Link to dbpedia http://dbpedia.org/resource/{LearningResourceType}
    Educational.IntendedEndUserRole Link to dbpedia http://dbpedia.org/resource/{IntendedEndUserRole}
    Technical.Location For videos use sameAs link yovisto --> http://www.yovisto.com/ontology/
    General.Keyword, {Category}.Description Link the word (or vocabulary) EUROVoc --> http://eurovoc.europa.eu
    News(The New York Times) --> http://data.nytimes.com/
    Linked Open Vocabularies (LOV)--> http://lov.okfn.org
    GEMET --> http://www.eionet.europa.eu/gemet/
    Government Data --> http://logd.tw.rpi.edu/
    Statistical Data --> statistics.data.gov.uk
    Social Semantic words--> http://vocabulary.semantic-web.at
    Products and food --> http://aims.fao.org
    Cultural collection --> http://pro.europeana.eu/linked-open-data
    National Agriculture Library --> http://agclass.nal.usda.gov
    Geographic --> eionet.europa.eu or http://data.ordnancesurvey.co.uk/
    Public data --> http://data.gov.uk
    Classification.Taxon Link to a taxonomy TaxonConcept --> http://lod.taxonconcept.org/
    Linked Open Ontologies --> http://lov.okfn.org
    All elements When refer to a school/company/course Education--> http://education.data.gov.uk
    Companies --> http://opencorporates.com/
    Open University --> data.open.ac.uk

    Acknowledgements

    We express our gratitude to the ODS project group for their support, co-operation, comments and suggestions.

    Appendix: XML to Turtle IEEE LOM Example

     <?xml version="1.0" encoding="UTF-8"?>
     <lom xmlns="http://ltsc.ieee.org/xsd/LOM">
         <general>
             <identifier>
                 <catalog>URI </catalog>
                 <entry>http://www.youtube.com/v/BebNsezt6r0?version=3&f=videos&c=YouTubeHarvester&app=youtube_gdata </entry>
             </identifier>
             <identifier>
                 <catalog>youtube </catalog>
                 <entry>http://www.youtube.com/watch?v=BebNsezt6r0 </entry>
             </identifier>
             <title>
                 <string language="el">Τι είναι βιολογικό. </string>
                 <string language="de">Was ist biologisch. </string>
                 <string language="en">What is organic. </string>
             </title>
             <language>en </language>
             <description>
                 <string language="de">Ein Ausbildungsvideo über die Unterschiede zwischen
                  konventioneller und biologischer Landwirtschaft. Darüber hinaus zeigt das video
                   das biologisches Zertifizierungslabel für mehrere Produkte. </string>
                 <string language="el">Ένα εκπαιδευτικό βίντεο για τις διαφορές ανάμεσα
                  στη συμβατική και τη βιολογική γεωργία. Επιπλέον το βίντεο δείχνει τη σήμανση
                  της βιολογικής πιστοποίησης σε διάφορα προϊόντα. </string>
                 <string language="en">A learning video about the differences between
                 conventional and organic farming. Furthermore the video shows the organic
                 certifier's logos for several products. </string>
             </description>
             <keyword>
                 <string language="en">certification </string>
                 <string language="el">πιστοποίηση </string>
                 <string language="de">Zertifizierung </string>
             </keyword>
             <keyword>
                 <string language="en">conventional farming </string>
                 <string language="el">συμβατική γεωργία </string>
                 <string language="de">konventionelle Landwirtschaft </string>
             </keyword>
             <keyword>
                 <string language="en">organic farming </string>
                 <string language="el">βιολογική γεωργία </string>
                 <string language="de">biologische Landwirtschaft </string>
             </keyword>
             <coverage>
                 <string>World </string>
             </coverage>
             <structure>
                 <source>LOMv1.0 </source>
                 <value>atomic </value>
             </structure>
             <aggregationlevel>
                2
             </aggregationlevel>
         </general>
         <lifeCycle>
             <version>
                 <string language="en"> Not available   </string>
             </version>
             <status>
                 <source>LOMv1.0 </source>
                 <value>final </value>
             </status>
             <contribute>
                 <role>
                     <source>LOMv1.0 </source>
                     <value>content provider </value>
                 </role>
                 <entity>
                    <![CDATA[BEGIN:VCARD
                    FN:YouTube
                    ORG:YouTube
                    N:YouTube
                    VERSION:3.0
                    END:VCARD]]>
                 </entity>
                 <date>
                     <dateTime>2011-05-17T05:53:31.00Z </dateTime>
                 </date>
             </contribute>
         </lifeCycle>
         <metaMetadata>
             <identifier>
                 <catalog>URI </catalog>
                 <entry>http://oe.confolio.org/scam/156/entry/2365 </entry>
             </identifier>
             <contribute>
                 <role>
                     <source>LOMv1.0 </source>
                     <value>creator </value>
                 </role>
                 <entity>
                     <![CDATA[BEGIN:VCARD
                    FN:Hannes Ebner
                    EMAIL;TYPE=INTERNET:hebner@kth.se
                    ORG:http://www.kth.se
                    N:Ebner;Hannes
                    VERSION:3.0
                    END:VCARD]]>
                 </entity>
                 <date>
                     <dateTime>2012-04-02T20:18:18.82Z </dateTime>
                 </date>
             </contribute>
             <contribute>
                 <role>
                     <source>LREv3.0 </source>
                     <value>enricher </value>
                 </role>
                 <entity>
                     <![CDATA[BEGIN:VCARD
                    FN:Hannes Ebner
                    EMAIL;TYPE=INTERNET:hebner@kth.se
                    ORG:http://www.kth.se
                    N:Ebner;Hannes
                    VERSION:3.0
                    END:VCARD]]>
                 </entity>
             </contribute>
             <contribute>
                 <role>
                     <source>LREv3.0 </source>
                     <value>enricher </value>
                 </role>
                 <entity>
                     <![CDATA[BEGIN:VCARD
                    FN:Angeliki Paparadi
                    N:Paparadi;Angeliki
                    VERSION:3.0
                    END:VCARD]]>
                 </entity>
             </contribute>
             <contribute>
                 <role>
                     <source>LOMv1.0 </source>
                     <value>validator </value>
                 </role>
                 <entity>
                     <![CDATA[BEGIN:VCARD
                    FN:Angeliki Paparadi
                    EMAIL;TYPE=INTERNET:apaparadi@gmail.com
                    ORG:http://www.agroknow.gr
                    N:Paparadi;Angeliki
                    VERSION:3.0
                    END:VCARD]]>
                 </entity>
             </contribute>
             <metadataSchema>LOMv1.0 </metadataSchema>
             <metadataSchema>LREv3.0 </metadataSchema>
             <language>en  </language>
         </metaMetadata>
         <technical>
             <format>video/x-ms-wmv </format>
             <format>application/x-shockwave-flash </format>
             <format>video/3gpp </format>
             <size>0 </size>
             <location>http://www.youtube.com/v/BebNsezt6r0?version=3&f=videos&c=YouTubeHarvester&app=youtube_gdata </location>
             <location>http://www.youtube.com/v/BebNsezt6r0?version=3&f=videos&c=YouTubeHarvester&app=youtube_gdata </location>
             <location>rtsp://v5.cache1.c.youtube.com/
             CjQLENy73wIaKwm96u3ssc3mBRMYDSANFEIQWW91VHViZUhhcnZlc3RlckgGUgZ2aWRlb3MM/0/0/0/video.3gp </location>
             <location>rtsp://v3.cache5.c.youtube.com/
             CjQLENy73wIaKwm96u3ssc3mBRMYESARFEIQWW91VHViZUhhcnZlc3RlckgGUgZ2aWRlb3MM/0/0/0/video.3gp </location>
             <duration>
                 <duration>PT0.269S </duration>
             </duration>
             <requirement>
                 <orComposite>
                     <type>
                         <source>LOMv1.0 </source>
                         <value>browser </value>
                     </type>
                     <name>
                         <source>LOMFRv1.0 </source>
                         <value>firefox </value>
                     </name>
                     <minimumVersion>1.7 </minimumVersion>
                     <maximumVersion>9.0 </maximumVersion>
                 </orComposite>
             </requirement>
    
             <installationRemarks>
                 <string language="en">Flash Player is necessary </string>
             </installationRemarks>
             <otherPlatformRequirements>
                 <string language="en">Multimedia </string>
             </otherPlatformRequirements>
    
         </technical>
         <educational>
             <interactivityType>
                expositive
             </interactivityType >
    
             <interactivityLevel>
                 <value>medium </value>
             </interactivityLevel >
    
             <semanticDensity>
                 <value>medium </value>
             </semanticDensity>
    
             <learningResourceType>
                 <source>LREv3.0 </source>
                 <value>presentation </value>
             </learningResourceType>
             <learningResourceType>
                 <source>LREv3.0 </source>
                 <value>video </value>
             </learningResourceType>
             <intendedEndUserRole>
                 <source>LOMv1.0 </source>
                 <value>learner </value>
             </intendedEndUserRole>
             <intendedEndUserRole>
                 <source>LOMv1.0 </source>
                 <value>teacher </value>
             </intendedEndUserRole>
             <intendedEndUserRole>
                 <source>LREv3.0 </source>
                 <value>parent </value>
             </intendedEndUserRole>
             <context>
                 <source>LREv3.0 </source>
                 <value>distance education </value>
             </context>
             <context>
                 <source>LREv3.0 </source>
                 <value>educational administration </value>
             </context>
             <context>
                 <source>LREv3.0 </source>
                 <value>pre-school </value>
             </context>
             <typicalAgeRange>
                 <string language="en">8-U </string>
             </typicalAgeRange>
             <difficulty>
                 <value>medium </value>
             </difficulty>
             <typicalLearningTime>
                 <duration>PT30M </duration>
             </typicalLearningTime >
             <description>
                 <string language="en">
                    This learning video should be played by a browser that supports Flash Player.
                 </string>
             </description>
             <language>
                en
             </language>
    
         </educational>
         <rights>
             <cost>
                 <source>LOMv1.0 </source>
                 <value>no </value>
             </cost>
             <copyrightAndOtherRestrictions>
                 <source>LOMv1.0 </source>
                 <value>yes </value>
             </copyrightAndOtherRestrictions>
             <description>
                 <string>http://creativecommons.org/licenses/by-nc-nd/3.0/ </string>
             </description>
         </rights>
         <relation>
             <kind>
                 <source>LOMv1.0 </source>
                 <value>ispartof </value>
             </kind >
             <resource>
                 <identifier>
                     <catalog>URI </catalog>
                     <entry>http://smilingvines.com/OrganicvsConventional.pdf </entry>
                 </identifier>
                 <description>
                     <string language="en">
                           The PDF file  explains the most important differences between organic and conventional farming
                     </string>
                 </description>
             </resource>
         </relation>
    
         <annotation>
             <entity>
                 <![CDATA[BEGIN:VCARD
                FN:Angeliki Paparadi
                EMAIL;TYPE=INTERNET:apaparadi@gmail.com
                ORG:http://www.agroknow.gr
                N:Paparadi;Angeliki
                VERSION:3.0
                END:VCARD]]>
             </entity>
             <date>
                 <dateTime>2012-05-16T00:00:00.00Z </dateTime>
             </date>
             <description>
                 <string language="en">Quality certified </string>
             </description>
         </annotation>
         <classification>
             <purpose>
                 <value>discipline </value>
             </purpose>
             <taxonPath>
                 <source>
                     <string language="en">Organic.Edunet Ontology </string>
                 </source>
                 <taxon>
                     <id>http://www.cc.uah.es/ie/ont/OE-Predicates#ProvidesExamplesOf ::
                     http://www.cc.uah.es/ie/ont/OE-OAAE#OrganicPrinciple </id>
                     <entry>
                         <string>ProvidesExamplesOf :: OrganicPrinciple </string>
                     </entry>
                 </taxon>
             </taxonPath>
             <taxonPath>
                 <source>
                     <string language="en">Organic.Edunet Ontology </string>
                 </source>
                 <taxon>
                     <id>http://www.cc.uah.es/ie/ont/OE-Predicates#CommentsOn ::
                     http://www.cc.uah.es/ie/ont/OE-OAAE#OrganicPrinciple </id>
                     <entry>
                         <string>CommentsOn :: OrganicPrinciple </string>
                     </entry>
                 </taxon>
             </taxonPath>
             <taxonPath>
                 <source>
                     <string language="en">Organic.Edunet Ontology </string>
                 </source>
                 <taxon>
                     <id>http://www.cc.uah.es/ie/ont/OE-Predicates#ProvidesExamplesOf ::
                     http://www.cc.uah.es/ie/ont/OE-OAAE#OrganicConventionalAgricultureComparison </id>
                     <entry>
                         <string>ProvidesExamplesOf :: OrganicConventionalAgricultureComparison </string>
                     </entry>
                 </taxon>
             </taxonPath>
             <taxonPath>
                 <source>
                     <string language="en">Organic.Edunet Ontology </string>
                 </source>
                 <taxon>
                     <id>http://www.cc.uah.es/ie/ont/OE-Predicates#ProvidesExamplesOf ::
                     http://www.cc.uah.es/ie/ont/OE-OAAE#OrganicStandard </id>
                     <entry>
                         <string>ProvidesExamplesOf :: OrganicStandard </string>
                     </entry>
                 </taxon>
             </taxonPath>
             <description>
                 <string language="en">
                This classification provides many examples of Organic Principles and Ontologies.
                 </string>
             </description>
             <keyword>
                 <string language="en">
                Organic
                 </string>
             </keyword>
             <keyword>
                 <string language="en">
                Farming
                 </string>
             </keyword>
         </classification>
     </lom>
    
      
    This example is shown in Turtle as follows:
    
    
    @prefix db:      <http://portal.organic-edunet.eu:8080/linkeddata/resource/> .
    @prefix lomvoc:  <http://ltsc.ieee.org/rdf/lomv1p0/vocabulary#> .
    @prefix lom:     <http://ltsc.ieee.org/rdf/lomv1p0/lom#> .
    @prefix OrEd:    <http://data.organic-edunet.eu/resource/> .
    @prefix foaf:    <http://xmlns.com/foaf/0.1/> .
    @prefix vcard:   <http://www.w3.org/2001/vcard-rdf/3.0#> .
    @prefix dcterms:  <http://purl.org/dc/terms/> .
    @prefix rdfs:    <http://www.w3.org/2000/01/rdf-schema#> .
    @prefix d2r:     <http://sites.wiwiss.fu-berlin.de/suhl/bizer/d2r-server/config.rdf#> .
    @prefix dbpedia:  <http://dbpedia.org/resource/> .
    @prefix xsd:     <http://www.w3.org/2001/XMLSchema#> .
    @prefix map:     <file:/home/flag/D2RQ/lom.n3#> .
    @prefix owl:     <http://www.w3.org/2002/07/owl#> .
    @prefix rdf:     <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
    @prefix lre:     <http://organic-edunet.eu/LOM/rdf/voc#> .
    
    <http://data.organic-edunet.eu/resource/resource/2909>
          a       lom:LearningObject ;
          lom:OtherPlatformRequirements
                  "Multimedia"@en ;
          lom:aggregationLevel
                  lomvoc:AggregationLevel-2 ;
          lom:annotation db:Annotation-2909-14023 ;
          lom:classification db:Classification-2401 ;
          lom:lifeCycleContribution db:Contribute-2909-12723 ;
          lom:copyrightAndOtherRestrictions
                  "yes" ;
          lom:cost "no" ;
          lom:coverage db:Coverage-2909-0 ;
          lom:description db:Description-2909-0 ;
          lom:educational db:Educational-2909-11632 ;
          lom:identifier db:Identifier-14075 , db:Identifier-14076 ;
          lom:keyword db:Keyword-2909-2 , db:Keyword-2909-1 , db:Keyword-2909-0 ;
          lom:lifeCycleStatus lomvoc:Status-final ;
          lom:technicalLocation <http://www.nationalfruitcollection.org.uk/> , <rtsp://v3.cache5.c.youtube.com/
             CjQLENy73wIaKwm96u3ssc3mBRMYESARFEIQWW91VHViZUhhcnZlc3RlckgGUgZ2aWRlb3MM/0/0/0/video.3gp> ,
             <rtsp://v5.cache1.c.youtube.com/CjQLENy73wIaKwm96u3ssc3mBRMYDSANFEIQWW91VHViZUhhcnZlc3RlckgGUgZ2aWRlb3MM/0/0/0/video.3gp>
             ,<http://www.youtube.com/v/BebNsezt6r0?version=3> ;
          lom:metaMetadataContribution
                  db:metaMetadataContribute-2909-9050 , db:metaMetadataContribute-2909-9051 ,
                  db:metaMetadataContribute-2909-9048 , db:metaMetadataContribute-2909-9049 ;
          lom:metaMetadataLanguage
                  "en" ;
          lom:metadataSchema
                  "LOMv1.0" , "LREv3.0" ;
          lom:metaMetadataIdentifier
                  db:MetaMetadataIdentifier-2909 ;
          lom:relation db:Relation-11556 ;
          lom:technicalRequirements db:requirement-2909-0;
          lom:structure lomvoc:Structure-atomic ;
          lom:technicalDuration "PT0.269S" ;
          lom:technicalInstallationRemarks "Flash Player is necessary"@en ;
          lom:technicalSize "0" ;
          dcterms:format "text/html" , "video/x-ms-wmv" , "video/3gpp" , "application/x-shockwave-flash" ;
          dcterms:language "en" ;
          dcterms:rights "The resource or at least part of it can be openly accessed,
            but specific copyright conditions may apply for its use/re-use. It is advisable
            to consult any specific copyright clauses included at the resource location,
            since Intute holds no responsibility for any violation of stated restrictions
            in accessing/using the resource. "@en , "http://creativecommons.org/licenses/by-nc-nd/3.0/" @unspecified ;
          dcterms:title "Was ist biologisch." @de , "Τι είναι βιολογικό." @el , "What is organic. "@en .
    ------------ Identifier --------------------------------
    db:Identifier-14075 lom:identifierCatalog "URI" ;
                        dcterms:identifier <http://www.youtube.com/v/> .
    db:Identifier-14076  lom:identifierCatalog "youtube" ;
                         dcterms:identifier <http://www.youtube.com/watch?v=BebNsezt6r0> .
    
    ------------ Metadata Identifier --------------------------------
    db:MetaMetadataIdentifier-2909  lom:identifierCatalog  "URI" ;
                                    dcterms:identifier "http://oe.confolio.org/scam/156/entry/2365" .
    
    ------------ Metadata Contribute --------------------------------
    
    db:metaMetadataContribute-2909-9048   lom:dateTimeValue
                  "2012-04-02T20:18:18.82Z" ;
                  lom:contributionEntity  db:metaMetadataContribtuion-9048 ;
                  lom:metaMetadataContributionRole  lomvoc:Role-creator .
    db:metaMetadataContribtuion-9048 vcard:EMAIL "hebner@kth.se" ;
                       vcard:FN "Confolio Administrator" , "Hannes Ebner" ;
                       vcard:N "Confolio Administrator" , "Hannes Ebner" ;
                       vcard:ORG "http://www.kth.se" ;
                       vcard:VERSION "3.0" .
    db:metaMetadataContribute-2909-9049  lom:dateTimeValue
                      "0000-00-00 00:00:00" ;
                  lom:contributionEntity db:metaMetadataContribtuion-9049 ;
                  lom:metaMetadataContributionRole  lomvoc:Role-enricher .
    db:metaMetadataContribtuion-9049  vcard:EMAIL "lynda.gibbins@nottingham.ac.uk" , "hebner@kth.se" ;
                      vcard:FN "Lynda Gibbins" , "Hannes Ebner" ;
                      vcard:N "Lynda Gibbins" , "Hannes Ebner" ;
                      vcard:ORG "http://www.kth.se" , "http://www.intute.ac.uk" ;
                      vcard:VERSION "3.0" .
    db:metaMetadataContribute-2909-9050 lom:dateTimeValue
                  "0000-00-00 00:00:00" ;
          lom:contributionEntity db:metaMetadataContribtuion-9050 ;
          lom:metaMetadataContributionRole  lomvoc:Role-enricher .
    db:metaMetadataContribtuion-9050  vcard:EMAIL "lynda.gibbins@nottingham.ac.uk" ;
                      vcard:FN "Angeliki Paparadi" , "Lynda Gibbins" ;
                      vcard:N "Angeliki Paparadi" , "Lynda Gibbins" ;
                      vcard:ORG "Intute / University of Nottingham (Intute)" ;
                      vcard:VERSION "3.0" .
    db:metaMetadataContribute-2909-9051 lom:dateTimeValue
                  "0000-00-00 00:00:00" ;
          lom:contributionEntity db:metaMetadataContribtuion-9051 ;
          lom:metaMetadataContributionRole  lomvoc:Role-validator .
    db:metaMetadataContribtuion-9051  vcard:EMAIL "apaparadi@gmail.com" ;
                      vcard:FN "Angeliki Paparadi" , "Confolio Administrator" ;
                      vcard:N "Angeliki Paparadi" , "Confolio Administrator" ;
                      vcard:ORG "http://www.kth.se" , "http://www.agroknow.gr" ;
                      vcard:VERSION "3.0" .
    ------------ Coverage --------------------------------
    db:Coverage-2909-0
          dcterms:coverage dbpedia:World , dbpedia:UnitedKingdom.
    ------------ requirement --------------------------------
    db:requirement-2909-0 lom:isCompositeOf db:SingleTechnicalRequirement_sample_1_1.
    db:SingleTechnicalRequirement_sample_1_1
          lom:orCompositeMaximumVersion
                  "9.0" ;
          lom:orCompositeMinimumVersion
                  "1.7" ;
          lom:orCompositeName lomvoc:OperatingSystemTechnology-firefox ;
          lom:orCompositeType lomvoc:RequirementType-browser .
    
    ------------ relation --------------------------------
    db:Relation-11556 lom:identifier db:relation_identifier_sample_1_1;
    	lom:relatedResourceDescription db:relatedDescription-1 ;
    	lom:relationKind dcterms:ispartof .
    db:relation_identifier_sample_1_1 lom:identifierCatalog "URI" ;
          dcterms:identifier  "http://smilingvines.com/OrganicvsConventional.pdf".
          
    db:relatedDescription-1
          dcterms:description "The PDF file  explains the most important
          differences between organic and conventional farming"@en .
    ------------ Description --------------------------------
    db:Description-2909-0  dcterms:description "Ένα εκπαιδευτικό βίντεο για τις διαφορές ανάμεσα
                  στη συμβατική και τη βιολογική γεωργία. Επιπλέον το βίντεο δείχνει τη σήμανση
                  της βιολογικής πιστοποίησης σε διάφορα προϊόντα." @el , "Ein Ausbildungsvideo über die Unterschiede zwischen
                  konventioneller und biologischer Landwirtschaft. Darüber hinaus zeigt das video
                   das biologisches Zertifizierungslabel für mehrere Produkte." @de , "A learning video about the differences between
                 conventional and organic farming. Furthermore the video shows the organic
                 certifier's logos for several products. "@en .
    
    ------------ Keyword --------------------------------
    db:Keyword-2909-0
          rdf:value "πιστοποίηση" @el , "certification" @en , "Zertifizierung" @de .
    db:Keyword-2909-1
          rdf:value "συμβατική γεωργία" @el , "conventional farming "@en ,
                    "konventionelle Landwirtschaft" @de .
    db:Keyword-2909-2
          rdf:value "βιολογική γεωργία" @el , "organic farming "@en , "biologische Landwirtschaft" @de.
    
    ------------ Contribute ---------------------
    db:Contribute-2909-12723 lom:dateTimeValue "2011-05-17T05:53:31.00Z" ;
                             lom:contributionEntity  db:lifecycleContribution-12723 ;
                             lom:dateTimeValue lomvoc:Role-contentprovider .
    db:lifecycleContribution-12723 vcard:FN "YouTube" ;
                                   vcard:N "YouTube" ;
                                   vcard:ORG "YouTube" ;
                                   vcard:VERSION "3.0" .
    ------------ Educational ---------------------
    
    db:Educational-2909-11632  lom:educationalContext lomvoc:Context-pre-school ,
          lomvoc:Context-educationaladministration , lomvoc:Context-distanceeducation ;
          lom:educationalDifficulty lomvoc:Difficulty-medium ;
          lom:educationDescription  db:EduDescription-3000 ;
          lom:educationalLanguage "en" ;
          lom:educationalIntendedUserRole   lomvoc:IntendedEndUserRole-parent ,
            lomvoc:IntendedEndUserRole-learner , lomvoc:IntendedEndUserRole-teacher ;
          lom:educationalInteractivityLevel lomvoc:InteractivityLevel-medium ;
          lom:educationalTypicalAgeRange db:Age-8953 ;
          lom:educationalTypicalLearningTime "PT30M" ;
          dcterms:type lomvoc:LearningResourceType-video , lomvoc:LearningResourceType-presentation .
    
    db:EduDescription-3000  dcterms:description "This learning video should
                            be played by a browser that supports Flash Player."@en .
    db:Age-8953
          rdf:value "8-U"@en .
    ------------ Annotation ---------------------
    db:Annotation-2909-14023  lom:dateTimeValue "2012-05-16T00:00:00.00Z" ;
                              lom:annotationDescription "Quality certified"@en ;
                              lom:annotationEntity   db:Annotation-14023.
    db:Annotation-14023       vcard:EMAIL "apaparadi@gmail.com" ;
                              vcard:FN "Angeliki Paparadi" ;
                              vcard:N "Angeliki Paparadi" ;
                              vcard:ORG "http://www.agroknow.gr" ;
                              vcard:VERSION "3.0" .
    ------------ Classification ---------------------
    db:Classification-2401  lom:classificationDescription  db:ClassificationDescription-1 ;
                            lom:classificationKeyword   db:ClassificationKeyword-1 ,
                                                        db:ClassificationKeyword-2 ;
                            lom:classificationPurpose lomvoc:Purpose-discipline ;
                            lom:taxonPath db:TaxonPath-2401-7669 ,
                                          db:TaxonPath-2401-7670 ,
                                          db:TaxonPath-2401-7671 ,
                                          db:TaxonPath-2401-7672 .
    db:ClassificationDescription-1  dcterms:description "This classification
                                    provides many examples of Organic Principles and Ontologies."@en .
    db:ClassificationKeyword-1    rdf:value "Organic"@en .
    db:ClassificationKeyword-2    rdf:value "Farming"@en .
    
    db:TaxonPath-2401-7669 lom:classificationTaxon  db:Taxon-2401 ;
                           lom:taxonpathSource "Organic.Edunet Ontology "@en .
    db:Taxon-2401    lom:taxonEntry "ProvidesExamplesOf :: OrganicPrinciple" ;
                     lom:taxonId "http://www.cc.uah.es/ie/ont/OE-Predicates#ProvidesExamplesOf ::
                            http://www.cc.uah.es/ie/ont/OE-OAAE#OrganicPrinciple" .
    
    db:TaxonPath-2401-7670 lom:classificationTaxon  db:Taxon-2402 ;
                           lom:taxonpathSource "Organic.Edunet Ontology "@en .
    db:Taxon-2402    lom:taxonEntry "CommentsOn :: OrganicPrinciple" ;
                     lom:taxonId "http://www.cc.uah.es/ie/ont/OE-Predicates#CommentsOn ::
                     http://www.cc.uah.es/ie/ont/OE-OAAE#OrganicPrinciple" .
    db:TaxonPath-2401-7671 lom:classificationTaxon  db:Taxon-2403 ;
                           lom:taxonpathSource "Organic.Edunet Ontology "@en .
    db:Taxon-2403    lom:taxonEntry "ProvidesExamplesOf :: OrganicConventionalAgricultureComparison" ;
                     lom:taxonId "http://www.cc.uah.es/ie/ont/OE-Predicates#ProvidesExamplesOf ::
                     http://www.cc.uah.es/ie/ont/OE-OAAE#OrganicConventionalAgricultureComparison" .
    db:TaxonPath-2401-7672 lom:classificationTaxon  db:Taxon-2404 ;
                           lom:taxonpathSource "Organic.Edunet Ontology "@en .
    db:Taxon-2404    lom:taxonEntry "ProvidesExamplesOf :: OrganicStandard" ;
                     lom:taxonId "http://www.cc.uah.es/ie/ont/OE-Predicates#ProvidesExamplesOf ::
                     http://www.cc.uah.es/ie/ont/OE-OAAE#OrganicStandard" .
     

    Appendix: Organic Edunet VoID

            @prefix void: <http://rdfs.org/ns/void#> .
            @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
            @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
            @prefix owl: <http://www.w3.org/2002/07/owl#> .
            @prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
            @prefix dcterms: <http://purl.org/dc/terms/> .
            @prefix foaf: <http://xmlns.com/foaf/0.1/> .
            @prefix wv: <http://vocab.org/waiver/terms/norms> .
            @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
    
            <a void:DatasetDescription;
            dcterms:title "A VoiD Description of the Organic.Edunet Dataset";
            dcterms:creator <http://www.uah.es/msicilia>;
            foaf:primaryTopic :OrganicEdunet.
    
            :OrganicEdunet   a  void:Dataset;
                       foaf:homepage  <portal.organic-edunet.eu/data> ;
                       foaf:page <portal.organic-edunet.eu> ;
                       dcterms:title "Organic Edunet";
                       dcterms:description "The metadata of collection of learning objects exposed through the Organic.Edunet portal";
                       dcterms:source <portal.organic-edunet.eu>;
                       dcterms:feature :TurtleFormat;
                       dcterms:feature :RDFXMLFormat;
                       dcterms:creator "http://www.uah.es/http://www.cc.uah.es/msicilia/";
                       dcterms:publisher :UAH;
                       dcterms:contributer "GRNET";
                       dcterms:created "2012-09-01";
                       dcterms:modified "2012-09-21";
                       dcterms:subject "http://dbpedia.org/page/Subsistence_agriculture";
                       dcterms:license "http://creativecommons.org/licenses/by-nc/3.0/"
                       void:sparqlEndpoint "portal.organic-edunet.eu/data/snorql";
                       void:datadump "portal.organic-edunet.eu/data/rdfdump.rdf";
                       void:exampleResource "portal.organic-edunet.eu/data/identifier110";
                       void:triples 10000;
    
    
            :OrganicEdunet2Dynalias a void:Linkset;
                    void:target :OrganicEdunet;
                    void:target :Dynalias;
                    void:linkPredicate owl:sameAs;
                    .
    
            :Miguel a foaf:person;
                rdfs:label "Miguel-Angel Sicilia";
                foaf:mbox <mailto:miguel@orgnaic-edunet.eu>.
    
            :RDFXMLFormat   a void:TechnicalFeature;
                     rdfs:label "RDF/XML" ;
                     rdfs:comment "Available as Linked Data in RDF/XML format";
                     dcterms:format "application/rdf+xml".
            :TurtleFormat   a void:TechnicalFeature;
                rdfs:label "Turtle" ;
                rdfs:comment "Available as Linked Data in Turtle format";
                dcterms:format "application/Turtle".
            :UAH  rdfs:label "University of Alcala";
                foaf:homepage "http://www.uah.es".
    
             

    Appendix: URIs for LOM vocabulary terms


    The main idea for definition of LOM vocabulary terms comes up on [[IEEEDCAM]] and the URIs are suggestion links based on xsd vocabulary.

    LOM element 1.7 Structure

    Value URI
    atomic http://ltsc.ieee.org/rdf/lomv1.0/vocab#Structure-atomic
    collection http://ltsc.ieee.org/rdf/lomv1.0/vocab#Structure-collection
    networked http://ltsc.ieee.org/rdf/lomv1.0/vocab#Structure-networked
    hierarchical http://ltsc.ieee.org/rdf/lomv1.0/vocab#Structure-hierarchical
    linear http://ltsc.ieee.org/rdf/lomv1.0/vocab#Structure-linear

    LOM element 1.8 Aggregation Level

    Value URI
    1 http://ltsc.ieee.org/rdf/lomv1.0/vocab#AggregationLevel-1
    2 http://ltsc.ieee.org/rdf/lomv1.0/vocab#AggregationLevel-2
    3 http://ltsc.ieee.org/rdf/lomv1.0/vocab#AggregationLevel-3
    4 http://ltsc.ieee.org/rdf/lomv1.0/vocab#AggregationLevel-4

    LOM element 2.2 Status

    Value URI
    draft http://ltsc.ieee.org/rdf/lomv1.0/vocab#Status-draft
    final http://ltsc.ieee.org/rdf/lomv1.0/vocab#Status-final
    revised http://ltsc.ieee.org/rdf/lomv1.0/vocab#Status-revised
    unavailable http://ltsc.ieee.org/rdf/lomv1.0/vocab#Status-unavailable

    LOM element 2.3.1 Role and 3.2.1 Role

    Value URI
    author http://ltsc.ieee.org/rdf/lomv1.0/vocab#Role-author
    publisher http://ltsc.ieee.org/rdf/lomv1.0/vocab#Role-publisher
    unknown http://ltsc.ieee.org/rdf/lomv1.0/vocab#Role-unknown
    initiator http://ltsc.ieee.org/rdf/lomv1.0/vocab#Role-initiator
    terminator http://ltsc.ieee.org/rdf/lomv1.0/vocab#Role-terminator
    validator http://ltsc.ieee.org/rdf/lomv1.0/vocab#Role-validator
    editor http://ltsc.ieee.org/rdf/lomv1.0/vocab#Role-editor
    graphical designer http://ltsc.ieee.org/rdf/lomv1.0/vocab#Role-graphicalDesigner
    technical implementer http://ltsc.ieee.org/rdf/lomv1.0/vocab#Role-technicalImplementer
    content provider http://ltsc.ieee.org/rdf/lomv1.0/vocab#Role-contentProvider
    technical validator http://ltsc.ieee.org/rdf/lomv1.0/vocab#Role-technicalValidator
    educational validator http://ltsc.ieee.org/rdf/lomv1.0/vocab#Role-educationalValidator
    script writer http://ltsc.ieee.org/rdf/lomv1.0/vocab#Role-scriptWriter
    instructional designer http://ltsc.ieee.org/rdf/lomv1.0/vocab#Role-instructionalDesigner
    subject matter expert http://ltsc.ieee.org/rdf/lomv1.0/vocab#Role-subjectMatterExpert

    LOM element 3.3 Metadata Scheme

    Value URI
    LOMv1.0 http://ltsc.ieee.org/rdf/lomv1.0/vocab#MetadataScheme-LOMv1.0

    LOM element 4.4.1.1 Type

    Value URI
    operating system http://ltsc.ieee.org/rdf/lomv1.0/vocab#RequirementType-operatingSystem
    browser http://ltsc.ieee.org/rdf/lomv1.0/vocab#RequirementType-browser

    LOM element 4.4.1.2 Name

    Operating System Technology

    Value URI
    pc-dos http://ltsc.ieee.org/rdf/lomv1.0/vocab#OperatingSystemTechnology-pc-dos
    ms-windows http://ltsc.ieee.org/rdf/lomv1.0/vocab#OperatingSystemTechnology-ms-windows
    macos http://ltsc.ieee.org/rdf/lomv1.0/vocab#OperatingSystemTechnology-macos
    unix http://ltsc.ieee.org/rdf/lomv1.0/vocab#OperatingSystemTechnology-unix
    multi-os http://ltsc.ieee.org/rdf/lomv1.0/vocab#OperatingSystemTechnology-multi-os
    none http://ltsc.ieee.org/rdf/lomv1.0/vocab#OperatingSystemTechnology-none

    Browser Technology

    Value URI
    any http://ltsc.ieee.org/rdf/lomv1.0/vocab#BrowserTechnology-any
    netscape communicator http://ltsc.ieee.org/rdf/lomv1.0/vocab#BrowserTechnology-netscapeCommunicator
    ms-internet explorer http://ltsc.ieee.org/rdf/lomv1.0/vocab#BrowserTechnology-ms-internetExplorer
    opera http://ltsc.ieee.org/rdf/lomv1.0/vocab#BrowserTechnology-opera
    amaya http://ltsc.ieee.org/rdf/lomv1.0/vocab#BrowserTechnology-amaya

    LOM element 5.1 Interactivity Type

    Value URI
    active http://ltsc.ieee.org/rdf/lomv1.0/vocab#InteractivityType-active
    expositive http://ltsc.ieee.org/rdf/lomv1.0/vocab#InteractivityType-expositive
    mixed http://ltsc.ieee.org/rdf/lomv1.0/vocab#InteractivityType-mixed

    LOM element 5.2 Learning Resource Type

    Value URI
    exercise http://ltsc.ieee.org/rdf/lomv1.0/vocab#LearningResourceType-exercise
    simulation http://ltsc.ieee.org/rdf/lomv1.0/vocab#LearningResourceType-simulation
    questionnaire http://ltsc.ieee.org/rdf/lomv1.0/vocab#LearningResourceType-questionnaire
    diagram http://ltsc.ieee.org/rdf/lomv1.0/vocab#LearningResourceType-diagram
    figure http://ltsc.ieee.org/rdf/lomv1.0/vocab#LearningResourceType-figure
    graph http://ltsc.ieee.org/rdf/lomv1.0/vocab#LearningResourceType-graph
    index http://ltsc.ieee.org/rdf/lomv1.0/vocab#LearningResourceType-index
    slide http://ltsc.ieee.org/rdf/lomv1.0/vocab#LearningResourceType-slide
    table http://ltsc.ieee.org/rdf/lomv1.0/vocab#LearningResourceType-table
    narrative text http://ltsc.ieee.org/rdf/lomv1.0/vocab#LearningResourceType-narrativeText
    exam http://ltsc.ieee.org/rdf/lomv1.0/vocab#LearningResourceType-exam
    experiment http://ltsc.ieee.org/rdf/lomv1.0/vocab#LearningResourceType-experiment
    problem statement http://ltsc.ieee.org/rdf/lomv1.0/vocab#LearningResourceType-problemStatement
    self assessment http://ltsc.ieee.org/rdf/lomv1.0/vocab#LearningResourceType-selfAssessment
    lecture http://ltsc.ieee.org/rdf/lomv1.0/vocab#LearningResourceType-lecture

    LOM element 5.3 Interactivity Level

    Value URI
    very low http://ltsc.ieee.org/rdf/lomv1.0/vocab#InteractivityLevel-veryLow
    low http://ltsc.ieee.org/rdf/lomv1.0/vocab#InteractivityLevel-low
    medium http://ltsc.ieee.org/rdf/lomv1.0/vocab#InteractivityLevel-medium
    high http://ltsc.ieee.org/rdf/lomv1.0/vocab#InteractivityLevel-high
    very high http://ltsc.ieee.org/rdf/lomv1.0/vocab#InteractivityLevel-veryHigh

    LOM element 5.4 Semantic Density

    Value URI
    very low http://ltsc.ieee.org/rdf/lomv1.0/vocab#SemanticDensity-veryLow
    low http://ltsc.ieee.org/rdf/lomv1.0/vocab#SemanticDensity-low
    medium http://ltsc.ieee.org/rdf/lomv1.0/vocab#SemanticDensity-medium
    high http://ltsc.ieee.org/rdf/lomv1.0/vocab#SemanticDensity-high
    very high http://ltsc.ieee.org/rdf/lomv1.0/vocab#SemanticDensity-veryHigh

    LOM element 5.5 Intended End User Role

    Value URI
    teacher http://ltsc.ieee.org/rdf/lomv1.0/vocab#IntendedEndUserRole-teacher
    author http://ltsc.ieee.org/rdf/lomv1.0/vocab#IntendedEndUserRole-author
    learner http://ltsc.ieee.org/rdf/lomv1.0/vocab#IntendedEndUserRole-learner
    manager http://ltsc.ieee.org/rdf/lomv1.0/vocab#IntendedEndUserRole-manager

    LOM element 5.6 Context

    Value URI
    school http://ltsc.ieee.org/rdf/lomv1.0/vocab#Context-school
    higher education http://ltsc.ieee.org/rdf/lomv1.0/vocab#Context-higherEducation
    training http://ltsc.ieee.org/rdf/lomv1.0/vocab#Context-training
    other http://ltsc.ieee.org/rdf/lomv1.0/vocab#Context-other

    LOM element 5.8 Difficulty

    Value URI
    very easy http://ltsc.ieee.org/rdf/lomv1.0/vocab#Difficulty-veryEasy
    easy http://ltsc.ieee.org/rdf/lomv1.0/vocab#Difficulty-easy
    medium http://ltsc.ieee.org/rdf/lomv1.0/vocab#Difficulty-medium
    difficult http://ltsc.ieee.org/rdf/lomv1.0/vocab#Difficulty-difficult
    very difficult http://ltsc.ieee.org/rdf/lomv1.0/vocab#Difficulty-veryDifficult

    LOM element 7.1 Kind

    Value URI
    ispartof http://purl.org/dc/terms/isPartOf
    haspart http://purl.org/dc/terms/hasPart
    isversionof http://purl.org/dc/terms/isVersionOf
    hasversion http://purl.org/dc/terms/hasVersion
    isformatof http://purl.org/dc/terms/isFormatOf
    hasformat http://purl.org/dc/terms/hasFormat
    references http://purl.org/dc/terms/references
    isreferencedby http://purl.org/dc/terms/isReferencedBy
    isbasedon http://purl.org/dc/terms/source
    isbasisfor http://ltsc.ieee.org/rdf/lomv1p0/terms#isBasisFor
    requires http://purl.org/dc/terms/requires
    isrequiredby http://purl.org/dc/terms/isRequiredBy

    LOM element 9.1 Purpose

    Value URI
    discipline http://ltsc.ieee.org/rdf/lomv1.0/vocab#Purpose-discipline
    idea http://ltsc.ieee.org/rdf/lomv1.0/vocab#Purpose-idea
    prerequisite http://ltsc.ieee.org/rdf/lomv1.0/vocab#Purpose-prerequisite
    educationalObjective http://ltsc.ieee.org/rdf/lomv1.0/vocab#Purpose-educationalObjective
    accessibility restrictions http://ltsc.ieee.org/rdf/lomv1.0/vocab#Purpose-accessibilityRestrictions
    educationalLevel http://ltsc.ieee.org/rdf/lomv1.0/vocab#Purpose-educationalLevel
    skillLevel http://ltsc.ieee.org/rdf/lomv1.0/vocab#Purpose-skillLevel
    securityLevel http://ltsc.ieee.org/rdf/lomv1.0/vocab#Purpose-securityLevel
    competency http://ltsc.ieee.org/rdf/lomv1.0/vocab#Purpose-competency

    Copyright and Other Restrictions

    Value URI
    Yes http://ltsc.ieee.org/rdf/LOM/rights#yes

    No http://ltsc.ieee.org/rdf/LOM/rights#No