Re: Including Semantics
Duane Nickull <[email protected]>
| Newsgroups | gmane.comp.web.services.ws-arch |
|---|---|
| Message-ID | <[email protected]> |
Assaf: Is there a chance I can set up a meeting with you this week at your office? Duane Burdett, David wrote: > Assaf > > There are interesting ideas in your email but I don't think you've > answered my original question which is how all this relates to the > Semantic Web activity and RDF ... see more detailed comments below. > > David > > -----Original Message----- > From: Assaf Arkin [mailto:[email protected]] > Sent: Thursday, February 13, 2003 6:33 PM > To: Burdett, David; 'Duane Nickull' > Cc: [email protected] > Subject: RE: Including Semantics > > What you want to have are different semantic languages and a > framework that associates all that information together. For > example, XSDL would define some of the semantics of a message. It > can tell me that a purchase order contains one or more line items, a > billing address and a shipping address. > [David Burdett] True, but XSDL does not tell you what a shipping > address >>means<<. It might be pretty obvious based on our common experience > and therefore does not need any explanation. But this is not the > case for much of the information transported in business documents. > XSDL only gives you a structure and method of identfying individual > pieces of information - it's not enough > > In a different language, e.g. WSDL, I could say that a purchase > order is required as the input for an operation and that the > operation does not result in an immediate response. > [David Burdett] Again I think you are making assumptions. For > example what do you mean by a "response". Does it mean, for example, > a) "I got the message but have done nothing with it", or b) "I've > got the message and it's structure looks OK, i.e. I haven't checked > that codes (e.g. productids) are valid, or stock availabilty", or c) > "I've checked it and here's information on the extend to which I can > satisfy your order". This is all semantic information that, I doubt > would go in a WSDL definition. > > You can introduce other languages that say interesting things about > that operation. For example, a cost language would introduce a cost > property and a way to express the cost calculated from purchase > order message. So you can say there's a property called 'cost' and > determine that value of that property given a purchase order message. > [David Burdett] I think I get this, but if you did have such a > language, who or what would use it? It's not clear to me. > > Another language could define an object called delivery with > multiple properties, reference the purchase order message as > indicating the product property, an accept response as indicating > the agent promising to deliver, and a delivery notice as indicating > truth of delivery property. That 'delivery' object does not exist, > but if you participate in the business choreography you can draw a > lot of conclusions about the delivery status by observing how its > virtual properties are modified during different states of the process. > > On a conceptual level this is very interesting since it allows the > development of even smarter applications based on what is already > there. That logical delivery object can be defined in terms of > existing purchase order scenarios, even if you're running a COBOL > application written thirty years ago. > [David Burdett] I agree that the being able to abstract existing > applications is important > > On a practical level, I will take a few years before we have the > understanding of how to define such semantics on a larger scale and > actual products that operate on that semantic. So right now it > doesn't solve any problem. > [David Burdett] Who do you think would be the right organization to > develop these semantics and how to define them. > > But if you look at a combination like WSCI + WSDL + XSDL you can see > that the semantic of WSCI express the context in which a WSDL > operation is used and the semantic of the WSDL operation expresses > what the WSDL type is used for. So we're already doing some limited > semantic work on a step by step basis. And just like the logical > delivery object above, the process that occurs between the services > doesn't really exist, it's only inferred from how they operate > together, and the operation doesn't really exist, it's only an > understanding of the meaning of sending some input and receiving > some output. > > arkin > > > -----Original Message----- > From: Burdett, David [mailto:[email protected]] > Sent: Thursday, February 13, 2003 12:15 PM > To: 'Assaf Arkin'; Burdett, David; 'Duane Nickull' > Cc: [email protected] > Subject: RE: Including Semantics > > Assaf > > I agree with all of your email, especially the need for > descriptions at the particle level, apart from the assertion > "For computer processing RDF gives you a good framework". > Perhaps it does, but for the problem in hand, I don't see how it > is directly usable now. How would you, for example, actually use > an RDF description of a business document when desiging, > building or operating a computer system that wants to generate > or process XML based business documents. > > David > > -----Original Message----- > From: Assaf Arkin [mailto:[email protected]] > Sent: Thursday, February 13, 2003 11:00 AM > To: Burdett, David; 'Duane Nickull' > Cc: [email protected] > Subject: RE: Including Semantics > > > > > I think it really boils down to how the information is > going to be >used<. Most information in business documents ends up > either being printed or displayed for human consumption, > or mapped to some internal format to populate > information in an ERP system say. In both these cases > you need a very clear definition of the meaning of the > data that either a human can understand as help when > viewing a document or can be used by another human to do > a good map between external and internal formats. I > don't see how RDF would help with this and I can't > imagine a software tool that could make good use of it > in this context. > > For computer processing RDF gives you a good framework > and it can also contain information for human > consumption (e.g. HTML formatted text). But practically > speaking, we're still at the point where people do all > that work, so what we need is way to annotate the > information and present some textual information to the > user. > > XSDL, WSDL and most other recent specifications have > ways of annotating definitions. Ideally you should be > able to annotate any definition, not just a top-level > one, e.g. a particle in the XSDL content, an operation > from a port type, etc. > > The namespace by itself is insufficient because you can > have multiple definitions in the same namespace. But > often some of the semantics is captured by the namespace > on its own. For example, > http://example.com/trading/futures may indicate that all > related definitions deal with trading in futures. It > won't tell you what a specific data type means, or what > a particular operation does. But when you browse a > repository of type/service/process definitions, it lets > you easily determine what context you are looking at. > > arkin > > > I accept I may be completely missing something - can > anyone clarify? > > David > > -----Original Message----- > From: Assaf Arkin [mailto:[email protected]] > Sent: Wednesday, February 12, 2003 9:49 PM > To: Burdett, David; 'Duane Nickull' > Cc: [email protected] > Subject: RE: Including Semantics > > > > -----Original Message----- > From: [email protected] > [mailto:[email protected]]On Behalf Of > Burdett, David > Sent: Wednesday, February 12, 2003 4:30 PM > To: 'Duane Nickull' > Cc: [email protected] > Subject: Including Semantics > > Duane asked ... > > >>>One missing component I would like to see is > semantics. David - do you > think there is a way to leverage the semantics > of UBL, CCTS for the WSAG?<<< > > Semantics is a whole big topic on its own, but > here's my take of the semantic information that > you might need to define. Note I'm looking at > this from a "business use" perspective: > > 1. Document Semantics. At the highest level a > namespace identifies a document as consisting of > a set of fields. Within this there are two > additional levels to consider: > > a) Individual fields. Each field needs to be > defined, e.g. what does "CustomerId" mean, e.g. > is it the ID by which the Customer identifies > themselves or the id which the supplier uses to > identify the customer? > > b) Fields within a document, e.g. The Customer > ID could appear can appear in multiple places in > the document - how does its meaning vary > depending on where it exists. > > 2. Context Dependent Semantics. The content of a > message can also depend on the context in which > it is being used, for example an Invoice in > Europe is different from an Invoice in the US as > it contains different fields. Similarly an > Invoice used in the travel industry contains > additional line item information (e.g flight > segments) that other industries (e.g. the > chemical industry) don't need. > > 3. Message Semantics. Messages >can< consist of > multiple parts where you could describe each > "part" as a document. You then need to, in the > context of the message, define what each > document mean, for example you might want to > attach a supplier generated delivery note when > requesting a "return materials advice" for some > faulty goods. In this case the delivery note is > evidence that delivery occured. This is > different from its first use when the delivery > note informs the buyer of what the supplier has > shipped, but not yet delivered. > > 4. Transaction Semantics. The same message with > the same structure and same semantics can be > treated differently depending on where it is > being sent and the context in which it is being > used. For example sending an Order Message to an > off-site archival service for archiving would > have different meaning than sending the > "identical" message to a supplier. > > So yes I think you could leverage the semantics > of UBL etc, but that is just the start and my > best >guess< is that you could use header > information in a SOAP message to codify the > semantics of the message ... although this sound > very non-RESTafarian ;) > > Also ... this is a trout hole ... how does the > W3C work on the Semantic Web fit in with all of > this ;) > > Just looking at the perspective of Semantic Web, > could we not use RDF to create maps of semantic > information? > > For example, I can describe the semantics of a > type using RDF (customerID) by referencing the > type definition, but also the semantics of the > content of a type (order/billing/address vs. > order/shipping/address) if I can reference an > XSD particle. And I can have both semantics, one > that applies to address in isolation, and one > that extends that semantics when address is used > in some context. > > I would guess that the same is possible for > transactions. For example, e.g. the address of > the invoice that is sent by activity X of > transaction Y. All I need is a way to reference > a resource that can be part of a larger resource > in the RDF description and then provide that > semantic in the RDF. > > arkin > > > > > > > > David > > > -----Original Message----- > From: Duane Nickull [mailto:[email protected]] > Sent: Wednesday, February 12, 2003 4:00 PM > To: Burdett, David > Cc: [email protected] > Subject: Re: Layers in the WSA (was RE: [Fwd: > UN/CEFACT TMG Releases > e-Bus ines s Architecture Technical > Specification for Public Review]) > > <SNIP/> > -- VP Strategic Relations, Technologies Evangelist XML Global Technologies **************************** ebXML software downloads - http://www.xmlglobal.com/prod/