View Issue Details
ID | Project | Category | View Status | Date Submitted | Last Update |
---|---|---|---|---|---|
0004267 | 10000-014: PubSub | Spec | public | 2018-04-30 14:26 | 2018-11-02 10:05 |
Reporter | Mariusz Postol | Assigned To | Matthias Damm | ||
Priority | none | Severity | major | Reproducibility | have not tried |
Status | assigned | Resolution | reopened | ||
Platform | Any | OS | ANy | OS Version | Any |
Summary | 0004267: Part 14 PubSub Section 5.2.3 DataSetMetaData - doesn't describe the semantics of the DataSet structure. | ||||
Description | The specification says:
I am not a native speaker but according to http://www.dictionary.com/browse/semantic?s=t
Semantics: the meaning, or an interpretation of the meaning, of a word, sign, sentence, etc. In this case Semantics in context of OPC UA Information Model is described in details in https://mpostol.gitbooks.io/object-oriented-internet/content/DataDiscovery/ The DataSetMetaData describes only fields encoding. It is a fundamental difference between what the specification says, and what I proposed many years ago. One of the goals of the object-oriented-internet project is how to make the DataSet semantics-aware. Unfortunately, it leads to misunderstanding. Recently my student asked me "what PubSub has in common with OPC UA" - the answer is the encoding and only encoding - more detailed discussion you can find at: | ||||
Tags | No tags attached. | ||||
Commit Version | |||||
Fix Due Date | |||||
|
Changed semantic to semantics but in general the DataSetMetaData provides more than just the field encoding.
Therefore semantics is right even it does not give the full blown information model. |
|
Yes, the DataSetMetaData provides more than just the field encoding, but not semantics that can be useful for M2M communication. Name and Description use native language and if well formatted can provide semantics in selected native language. Unfortunately, this information is hard to be understood by machines. Even if you use Artificial Intelligence the Name and Description meaning can be recovered with the probability << 1. In other words, for writing a column in a newspaper the text provides semantics, but try to use a computer to understand this text. Can you provide any real scenario how to use meta-data to change how to proceed the data, e.g screen position where the data is displayed? See for example project that is underway and where we need to solve problems like this: Networking.HMI available at: https://github.com/mpostol/OPC-UA-OOI/projects It leads to very serious interoperability problem that MUST BE addressed by the specification. |
|
There is a discussion you may be interested: https://www.linkedin.com/feed/update/urn:li:activity:6463706039991705600 To clarify; in other words - my understanding is that the DataSet concept is copy/past of the subscription concept born at the very beginning of the OPC life cycle. The difference is that the OPC subscription is created in the context of OPC Client/Server connection - it makes them tightly coupled components. My concern is if it can be applied for the publication/subscription scenario that makes components peer and loosely coupled. Hope it helps. |
Date Modified | Username | Field | Change |
---|---|---|---|
2018-04-30 14:26 | Mariusz Postol | New Issue | |
2018-06-05 16:09 | Matthias Damm | Note Added: 0009103 | |
2018-06-05 16:09 | Matthias Damm | Status | new => resolved |
2018-06-05 16:09 | Matthias Damm | Resolution | open => won't fix |
2018-06-05 16:09 | Matthias Damm | Assigned To | => Matthias Damm |
2018-06-10 12:13 | Mariusz Postol | Note Added: 0009133 | |
2018-06-10 12:13 | Mariusz Postol | Status | resolved => feedback |
2018-06-10 12:13 | Mariusz Postol | Resolution | won't fix => reopened |
2018-06-10 12:16 | Mariusz Postol | Note Edited: 0009133 | |
2018-10-23 15:46 | Jim Luth | Status | feedback => assigned |
2018-11-02 10:05 | Mariusz Postol | Note Added: 0009514 |