RE: [plcs-dex] What is a DEX

["Rob Bodington" <rob.bodington@eurostep.com>]

Mats Nilsson raised the question before "What is a DEX" and pointed out that
we use the term DEX to mean two different things.

1) A DEX identifies a subset of the ISO 10303-239 (PLCS) information model
required to support a set of identified arrows and activities in the ISO
10303-239 Activity model.

2) A DEX is also used to refer to a package of data that is exchanged. I.e.
the actual data that is exchanged in accordance with the DEX information
model. 

To avoid confusion, I propose that we refer to the second use of DEX as "DEX
data sets".

Regards
Rob


> -----Original Message-----
> From: Barker, Sean (UK) [mailto:sean.barker@baesystems.com]
> Sent: 30 August 2005 09:34
> To: peter.bergstrom@eurostep.com; DEXS-PLCS-OASIS (E-mail)
> Subject: RE: [plcs-dex] What is a DEX
> 
> 
> Peter,
> 
> 	Your summary is, for the most part, correct. My note was
> essentially about a detail of the definition of a DEX, namely, whether
> Message is part of a DEX, or whether it is external to a DEX.
> 	It is also a clarification of the statement "a File will contain
> one DEX". Since a DEX is a specification, the question was whether this
> statement meant it conformed to one DEX specification, with multiple
> instantiations, or whether it meant a single instantiation. Restriction
> of the number of instantiations is, therefore, a matter of exchange
> agreement (business rule).
> 	The term Task Set arises from the AAM lifecycle stage, in which
> the DEX supports the evolution of the support solution. One element of
> this is the contracting for the set of tasks applicable to an equipment
> and its sub-equipments. The function of task set is mainly to control
> contracting for the set of tasks, as well as interchange the task
> descriptions. It is this contracting/lifecycle control aspect of Task
> Set that has been put out of scope.
> 	I hope this clarifies.
> 
> 
> 
> Sean Barker
> 0117 302 8184
> 
> -----Original Message-----
> From: Peter Bergstrom [mailto:peter.bergstrom@eurostep.com]
> 
> Sent: 27 August 2005 08:27
> To: Barker, Sean (UK); DEXS-PLCS-OASIS (E-mail)
> Subject: RE: [plcs-dex] What is a DEX
> 
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> 
> I'm sorry, but I don't understand. I probably misunderstood something
> very basic here, so I better explain my view and let wiser men (and
> women) tell me what I didn't understand...
> 
> I though the DEX was a specification for an exchange file. In my mind,
> the DEX is standardized and fixed through OASIS, you would never send
> 'it'. You would send and exchange file _conforming_ to the DEX.
> 
> DEX3 would in my mind specify how tasks have to be structured/encoded to
> be transmitted accorded to DEX3 and PLCS. I thought DEX3 should not say
> you cannot send more than one task at the time (that, too me, would be
> quite rediculous). It would specify the structure/format for instances
> according to the Task(_method)-entity and related entities.
> 
> If someone would want to limit the exchange file to say 'just one task
> per file', they would do so in the exchange agreement, I would say, or
> possibly in the Business concept, but it is not part of the DEX to make
> such limitations.
> 
> Regarding the name 'Task-set', I have always wondered why the 'set' was
> there. The DEX shouldn't either specify you have to send a set of tasks.
> In my mind, an exchange file conforming to a future DEX3 specification
> could contain 1 or many tasks. I would actually prefer to have the name
> be 'task', not 'task set'.
> 
> If I have misunderstood the entire issue with your email here, please
> tell me so and don't waste more time on this. If I haven't, I'm
> worried...
> 
> 
> Peter
> --
> Peter Bergstrom          office: +46-8 200 440
> Eurostep AB              mobile: +46-708 111 966
> Vasagatan 38             fax: +46-708 111 965
> 111 20 Stockholm
> Sweden
> 
> -----Original Message-----
> From: Barker, Sean (UK) [mailto:sean.barker@baesystems.com]
> Sent: den 26 augusti 2005 16:17
> To: DEXS-PLCS-OASIS (E-mail)
> Subject: [plcs-dex] What is a DEX
> 
> 
> 
> At DEX 3 meeting, we had a discussion arising from the definition of a
> DEX in the context of Task-list. The discussion is summarized in the
> attached figure. Essentially the question is whether the message entity
> is part of the DEX, but the argument goes as follows:
> 
> 1) A DEX is a design, rather than a physical file (DEX as Realized).
> 
> 2) Create temporary term "DEX content item", meaning everything but the
> message.
> 
> 3) An exchange consists of a message AND [[Exactly one DEX content item]
> OR
> 							[Many DEX
> content item]]
> 
> The user requirement (Norwegian Frigate) was for many DEX content items.
> 
> 4) A DEX is either [The DEX content items] OR [The message entity AND
> the DEX content items]
> 
> The preferred solution was [Message AND DEX content items] (Bottom
> right, in red).
> 
> In the case of DEX 3, the content item is a Task, and
> Message.Content_item[i] points to each Task.
> No DEX can contain the content of any other DEX.
> 
> 5) Note: the various items in the DEX are independent of each other, and
> the fact that they come as a collection is merely a convenience, for
> example, to avoid having to manage too many files. Tool vendors have a
> valid input at this point. The number of items per DEX may be restricted
> by business rule.
> 
> 6) We can now delete the term "DEX content item", and say, say, DEX 3
> contains a message and several Task descriptions.
> 
> Note: The users have decide to restrict the scope of DEX 3 to Task. This
> is narrower than the original Task-set, wherein the Task-set would
> define a collection for a specific purpose and provide any appropriate
> meta-data. Discussions have been started about generalizing DEX 5 to
> cove such a requirement.
> 
> DO NOT SHOOT THE MESSENGER.
> 
> Sean Barker
> 0117 302 8184
> 
> 
> 
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