Extensible use of RDF
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Extensible use of RDF in a Business Context, paper presentation, W3C WWW09 conference, Amsterdam, 2000
![Extensible use of RDF in a Business Context Kerstin Forsberg Viktoria Institute and Adera [email_address] Lars Dannstedt Volvo Information Technology, Web Program Center [email_address] Resource Description Framework](https://image.slidesharecdn.com/extrdfwww9-12753320305631-phpapp01/85/extensible-use-of-rdf-1-320.jpg)
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Extensible use of RDF
- 1. Extensible use of RDF in a Business Context Kerstin Forsberg Viktoria Institute and Adera [email_address] Lars Dannstedt Volvo Information Technology, Web Program Center [email_address] Resource Description Framework
- 4. Current focus on m etadata : E nhance discovery of information W hat to cover in a metadata recommendation for our intranet? Central ly defined recommendations with code examples: <meta name=”Org” content=”VIT, 2510”> <meta name=”Subject” content=”IT, Security”> <meta name=”Author.name” content=”Pelle Persson”> <meta name=”Author.email” content=”it1.ppersson@memo.volvo.se”> What is metadata? How can we use Dublin Core on our intranet?
- 8. Three different resource descriptions areas Descriptions of Information resources Descriptions of Business resources Descriptions of Communication resources Document Dublin Core Metadata Element Set Schema Mobile Devices Composite Capability/ Preference Profiles Schema Business Unit OIM Business Engineering Model Schema
- 9. Our model for News Exchange 1(4) Business vcb: Information vci: Communication vcc: Volvo Core vc: A model for describing and integrating the resources description areas
- 10. Our model for News Exchange 2(4) OrgNode vcbo: Business vcb: Information vci: Service vcbs: Employee vcbe: Communication vcc: Volvo Core vc: A model for describing and integrating the resources description areas using namespaces , …
- 11. Our model for News Exchange 3(4) BizObject Business Unit Support Unit OrgNode vcbo: Service vcbs: OrgNode Employee vcbe: Business vcb: InfoObject Information vci: CommunicationObject Communication vcc: Communication Channel Volvo Core vc: Business Area Dept News Instruction WebPage Distri- bution Subscrip- tion Employee Service A model for describing and integrating the resources description areas using namespaces, classes and subclasses , … News InfoObject
- 18. An example of a local schema, VIT extensions VIT: Information vci: InfoObject News Instruction Communication vcc: CommunicationChannel (Email, Fax, Paper, Web) CommunicationObject Subscription Distribution Employee vcbe: Employee Service vcbs: Service Business Unit Support Unit OrgNode vcbo: OrgNode Business Area Dept Service Bureau News BPU Team Appl Service Service Bureau Volvo Core vc: WebPage Business vcb:
- 19. An example of a local schema, VIT extensions VIT: Information vci: InfoObject News Instruction Communication vcc: CommunicationChannel (Email, Fax, Paper, Web) CommunicationObject Subscription Distribution Employee vcbe: Employee Service vcbs: Service Business Unit Support Unit OrgNode vcbo: OrgNode Business Area Dept Service Bureau News BPU Team Appl Service Service Bureau Volvo Core vc: WebPage Business vcb:
- 21. RDF Statement <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:vc i ="http://volvo.se/vc i -namespace/schema.rdf#"> <rdf:Description rdf:about="http://vit.volvo.se/153-news/ vits-0067.xml "> <rdf:type resource=”http://volvo.se/vc i -namspace/schema.rdf# News ”/> < vc i :headline > XML consultancy ... < /vc i :headline > </rdf:Description> </rdf:RDF> vits-0067.xm l headline resource property property value To be read: vits-0067.xml of the class News HAS headline “XML consultancy during the millennium shift” XML consultancy during the millennium shift
- 22. RDF Statement , abbreviated form Or in abbreviated form: <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:vc i ="http://volvo.se/vc i -namespace/schema.rdf#"> <vc i : News rdf:about="http://vit.volvo.se/153-news/ vits-0067.xml "> < vc i :headline > XML consultancy during the millennium shift < /vc i :headline > </vc i : News > </rdf:RDF> vits-0067.xm l headline resource property property value To be read: vits-0067.xml of the class News HAS headline “XML consultancy during the millennium shift” XML consultancy during the millennium shift
- 25. Property typing Example: declaration of type of date <rdfs:Class rdf:ID="DateType"/> <DateType rdf:ID="BestBefore"> <rdfs:label xml:lang="en">Best-before date</rdfs:label> </DateType> <DateType rdf:ID="Creation"> <rdfs:label xml:lang="en">Creation date</rdfs:label> </DateType> <DateType rdf:ID="Obsolete"> <rdfs:label xml:lang="en">Obsolete date </rdfs:label> </DateType> <DateType rdf:ID="Release"> <rdfs:label xml:lang="en">Release date</rdfs:label> </DateType> <rdf:Property ID="dateType"> <rdfs:domain rdf:resource="#InfoObject"/> <rdfs:range rdf:resource="#DateType"/> </rdf:Property>
- 26. Property typing Example: RDF encoded type of date <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:vc="http://volvo.se/vc-namespace/schema.rdf#" xmlns:vci="http://volvo.se/vci-namespace/schema.rdf#"> <vci:News rdf:about="http://vit.volvo.se/153-news/vits-0067.xml"> <vc:date rdf:parseType="Resource"> <rdf:value> 2000-01-05 </rdf:value> <vci:dateType rdf:resource="http://volvo.se/vci-namspace/schema.rdf# BestBefore "/> </vc:date> ... </vci:News> </rdf:RDF> 2000-01-05 BestBefore vc:date rdf:value vci:dateType vits-0067.xm l
- 27. Properties for a Resource: Example News with ”headline” property Domain: InfoObject - subClassOf: vci:InfoObject Schemas News vci:News about Instance headline coverage ... vci:headline = ” XML consultancy during the millennium shift ” - subPropertyOf: factProperty headline
- 28. Properties for a Resource: Example News with ”coverage” property Domain: InfoObject Range: BizObject date/validFrom date/validTo relation/Supply ... vit:ApplService vci:coverage = vit153:#WebConsulting vci:News about Instances headline coverage ... Schemas - subClassOf: vci:InfoObject News - subPropertyOf: vc:factProperty coverage - subClassOf: vcb:BizObject vcbs:Service ApplService
- 32. Appendix: A framework for the next generation of intranets BizObject Business Unit Support Unit OrgNode vcbo: Service vcbs: OrgNode Employee vcbe: Business vcb: InfoObject Information vci: CommunicationObject Communication vcc: Communication Channel Volvo Core vc: Business Area Dept News Instruction WebPage Distri- bution Subscrip- tion Employee Service 2) An extension to the model describing and organising the communication of information in the business. 3 ) An extension to the model describing and integrating nodes and relations in networking organisations. 1) A model for describing three different areas of resources: business, information and communication, and integrating the resources description areas by means of generic classes, constrains and relations.
Notas do Editor
- Together with Lars, I will describe RDF, which is an interesting part of the XML family. We think that RDF has great potentials and therefore we have been experimenting with it. I will motivate and introduce the framework that we propose. And Lars, will take you into the details of RDF . And he will also give examples from, what we have called an extensible use of RDF in a Business Context . Lars will also list what kind of RDF enabled tools that we would like to see in the future. So – what’s RDF – we all hear a lot about XML these days – but what is RDF ?? RDF is an acronym for Resource Description Framework. RDF is a common infrastructure to encode , exchange and reuse metadata. RDF is an important mechanism to enable the semantic web . We have been experimenting with RDF to see how it could be used in a business context . => In our work, Lars and I, have been heading for the next generation of intranets.
- W e argue that, the next generation of intranets: … That is, new types of information resources , such as expanded business plans and specifications of e-business services … Which means, new types of communication resources , such as the wide spectrum mobile and wireless devices … Which give us, new types of business resources , such as new business services and new communities of customers and employees => To visualize the next generation of intranets, we introduce a news exchange application that has been the playground for our experiments with RDF.
- A manager wants to spread the news about one of the services her organisation offer during the millennium shift. She would like to be able to easily add correct news information on the intranet. She would also like to be sure that the news reaches ” whom it may concern ”. And, of course, she wants the information to be easily discovered. Let’s see what requirements , such a scenario implies: First we need, a web based form - on the department’s home page to write the news message. A form that automatically adapts to the context of the department. A form that includes all data, and also, all metadata . All of them with relevant values in drop-down menues . And of course , all data and metadata should be validated within the departments context . Secondly, next generation of intranets should include good exchange mechanisms – so that the creator can be confident that all relevant persons and organisations receive the news in a way that is chosen by each one. This means that the news message reaches all customers and also, people which the department co-operate with, as well as colleagues in the same organisation.That means: implicit receivers … / explicit receivers … Afterwards, a complete distribution list should be available. Next generation of intranets should, of course , support information discovery – so that the creator can be sure of that the information is searchable. Anyone should be able to discovery the news through metadata , such as creation date, the creator, what kind of services the news is about, and so on => So, a lot of metadata seems to be needed for the next generation of intranets!!
- Currently, infomasters, site owners, content providers, and so on, ask themselves: What is metadata? And more specific – ” What to cover in a metadata recommendation for our intranet? In many organisations recommendations, such as this one , is published to define the use of metadata. Nowadays, many organisations use the Dublin Core as a template for their own intranets. Dublin Core is a metadata element set proposed for the public Internet. The question then becomes; How can we use Dublin Core on our intranet? We have experiences from such a recommendation called the Volvo Core . However, we identified some problems with it. => But first – a short introduction to Dublin Core …
- Dublin Core is a basic metadata element set for discovery of existing information on the public Internet. Usually, the metadata is encoded inside the information resource itself. The metadata becomes part of the information resource which give us discoverable information . The Dublin Core vocabulary is captured in the follwoing three groups, that is; a) Content b) Intellectual properties c) and, the Instantiation itself. Many organisations set up there own Core vocabulary , and uses DC as a template. The Volvo Core recommendation is one example. This is a code example from a html-file that includes Volvo Core specified metadata. Instead of DC – they use VC. => We have experienced some problems when the Volvo Core recommendation was defined and implemented.
- First - Metadata schemas for information resources often makes assumptions about the business. However, these assumptions are rarely made explicit . For example ; What should the metadata element Coverage refer to in the business model? Secondly - Information resources are not just static web pages. A information resource could be communicated as a dynamic web page , it could also be included in a e-mail newsletter , or it could be distributed as a short message to a mobile device. Also, the recommendation was defined top-down in the organisation. And, based on the assumption of a hierarchical organisation. But groups and local units need to control and define information resources according to their own practice . The last main problem we identified, was that recommended metadata are seldom used for metadata creation and validation , in an effective way. This list of problems is not a critique of Dublin Core. It is to be seen as a consequence of trying to describe information resources - not taking into account the context in which end users create and consume information. => So, how can we capture the context for information creation and usage???
- Our point of departure is to describe Resources in Context We see resources as assets if they have a structured description, which makes them maintainable, usable , and reusable . One, of very many, definitions of metadata is that it is “ … structured , encoded data that describe entities …” We prefer the phrase: structured resources description , and have used it instead of metadata We argue that the description should be separated from the resource itself . We do need a mechanism to be able to constrain the context in which defined resources may be used Often, such a mechanism is called Schema . We argue that a set of schemas is needed. => Based on the experiences , our conclusion is that the descriptions should be separated into three different areas of resources.
- The three areas we have identified are: business, information and communication. To illustrate these areas - we present one community for description of resources within each area. The examples are also used in our model. In the information area we use the Dublin Core initiative for describing Documents . In the communication area we selected the Mobile Access Interest Group, part of the World Wide Web Consortium, and their CC/PP proposal for describing Mobile Devices . From the business area we use one part of something called Open Information Model (OIM) from the Metadata Coalition, as our example to describe Business Units .
- Here, I will give an overview of the model that we propose for the News Exchange application. The schemas included are relevant for a service company . A manufacturing company will have other classes, properties and relations. The model is applicable for a large organisation . As you see, we base the model on the Volvo Core and we have divided it into the three resource description areas that we already mentioned. => Here I will introduce some of the XML- and RDF-concepts used in our model to describe and intergrate resources .
- Namepaces is one important XML-concepts that we use. Each namespace covers an area that has its own vocabulary - defined in its own schema. We already separeted the vocabulary to describe information , business and communications resources . It is also obvious that t he vocabulary to describe Employees differs from the vocabularies describing Organisations and Services .
- RDF Schemas offers the possibility to define classes and sub-classes For example: the class “News” is declared as a subclass of InfoObject.
- Here is a complete picture of our model for the News exchange application. It is rather messy. But as you will see I will highlight some of the interesting property constrains that sets the context for resources. That is; headline, coverage ,date, and also, relation. => Together they exemplifies some very useful mechanisms – that is different ways to property constrain.
- To be able capture the context for information creation and usage we have noticed that it is very useful to use different ways to constrain properties. Headline is an example of a kind of property that describe the resource itself W hile coverage is a kind of property that relates a information resource to one, or many, business resource s . We have found that the contextual kind of properties , such as coverage , often are the most “important” properties. A a nother experience is that it is very useful to be able to type properties . Both properties that qualify the property itself and its lifesycle , such as date s ; BestBefore, Creation, Obsolete and Release. All of them - important date for an information resource. We also find it very useful to qualify the relations between resources . An example is the relation between nodes in the organisation that we have defined as; BelongTo / Contain and CooperateWith => Lars will now describe the set of RDF and RDF Schema mechanisms that we hav e used in our News exchange model .
- So, let us have a brief look at our RDF implementation. Only quite basic RDF-constructs were needed, like classes, subclasses, subproperties, property typing and domain and range constraints. I will start with the most basic part; the RDF statement.
- The RDF statement is a triple that is used in the metadata instances to assign a property and its value to a resource. The property value can point to another resource or be a literal value, as in this example, where the bulletin is the resource and the headline is the property. ------------------------------------------------------------------------------------------------- The statement encoded in RDF has Description as the container element. The “about” attribute points to the resource , the bulletin. The child element is “headline” with its content. Additionally: The type element tells us that the bulletin belongs to the class “News”, defined in the Volvo Core Information namespace (vci).
- By using the Volvo Core Information namespace we can express the RDF statement in a more compact form . In this case, the News element has the “about” attribute and headline is its child element. Most of the RDF statements in our News application are in this form.
- In the schema for the Volvo Core Information namespace we define the class InfoObject. It is defined by the label and comment properties from the RDF Schema. ------------------------------------------------------------------------------------------------ The class “News” is declared as a subclass of InfoObject. Each class defined in the News application has to be part of our class hierarcy.
- Property categories All properties in our model have to be a subproperty of one of four predefined properties. The predefined properties are derived from the Open Information Model (OIM), which proposes the categories term, fact, action and inference . The Term and Fact properties are normally easy to decide. An example of an Action property is the property &quot;date&quot;. When used for Information Objects, date often will trigger distribution, removal from a site a so on . An example of an Inference property is the property &quot;distributeTo&quot;. This property is used in distribution lists. It is also used in subscriptions to give the address of the subscriber. The application must create an aggregated distribution list at the event of distribution, removing multiple occurrences of receivers.
- Property typing Often there is a need to further qualify a property value. The properties 'date' and 'relation' are examples of properties that are likely to be used for different purposes. While an Information Object may have dates like date-of-creation, date-of-release, the dates of an organization node may be valid-from-date and valid-to-date. As you can see in the schema we define the class DateType and then one instance for each value: BestBefore, Creation, Obsolete and Relase. Similar declarations are done in other namespaces with other values. ----------------------------------------------------------------------------------------------- The property ”dateType” will be defined with the domain InfoObject and with a range that is the instances of class DateType.
- This is how the best-before-date for the News bulletin is coded. The date element is a container element for the ”value” (January 5th) and ”dateType” (BestBefore).
- And, now to the defintion of properties. The first example is property headline. ----------------------------------------------------------------------------------------------- As we say earlier the class “News” is defined as a subclass of InfoObject. ----------------------------------------------------------------------------------------------- The property “headline” is categorized as a ”fact” property. ---------------------------------------------------------------------------------------------- The domain constraint tells us that headline is only allowed in instances of the class InfoObject. We have no range constraints. In the next example we will take a look at the property “coverage” ----------------------------------------------------------------------------------------------
- ---------------------------------------------------------------------------------------------- In this example the News bulletin covers the service “WebConsulting” which is an instance of the class ApplService, defined by Volvo IT (vit). ---------------------------------------------------------------------------------------------- And, News is a subclass of InfoObject as earlier. ---------------------------------------------------------------------------------------------- The property “coverage” is categorized as a “fact” property. ---------------------------------------------------------------------------------------------- Its domain is defined as the class InfoObject. ---------------------------------------------------------------------------------------------- ApplService is a subclass of Service which in turn is a subclass of BizObject. ---------------------------------------------------------------------------------------------- Its range is restricted to the class BizObject, that is: a News bulletin can cover business objects like Organisation nodes, Employees or Services.
- To summarize: We have now briefly gone through the RDF constructs, which we have used to build out News exchange model
- On our wish list are tools which facilitate the development of an RDF-based solution. From the modeling stage to production. Such tools are required to extend our simple News application to a full-scaled application. --------------------------------------------------------------------------------------------- UML to RDF support. (We follow the discussions in the RDF mailing list about UML and XMI, the eXtensible Metadata Interchange). --------------------------------------------------------------------------------------------- XML editing of metadata which can take RDF domain and range constraints into account --------------------------------------------------------------------------------------------- Web browser with RDF-support. Like Mozilla with eXtensible User Interface Language. --------------------------------------------------------------------------------------------- Generic database support. We are looking forward to a generic database schema that can accomodate arbitrary RDF data structures. --------------------------------------------------------------------------------------------- RDF knowledgeable search engines
- With necessary tools available we believe that RDF used in a Business Context enables next generation of intranets. We base this on the experiences from the work with RDF to define our News Exchange Model which: Question: Do you have thoughts about the impact on an organization. Answer Lars: Web IS decentralized. Therefore, we want our schemas to be defined and maintained at relevant levels in the organization. A highly decentralized maintenance, but still with a common base. Kerstin: In one of the references in our paper the process to define and maintain metadata standards is described as a ‘complex social process’ Answer Kerstin: Our experiences is that each part in the organsiation has their special vocaloblury and also, different types of information and ways to communicate.