ISSUE-158: Introduction and goals
Introduction and goals
- State:
- CLOSED
- Product:
- Time ontology in OWL
- Raised by:
- Simon Cox
- Opened on:
- 2017-04-12
- Description:
- From https://www.w3.org/XML/2007/qts-timeont-comments
The document appears to lack any description of its goals.
Armed only with the title, a reader might expect an effort to develop a philosophically sound account of time, working from first principles — perhaps a little discussion of Augustine's reflections on time in the Confessions, maybe some Bergson, maybe some Heidegger. Or perhaps a more empiricist account, in which Carnap and Popper might figure. Other readers may expect an attempt to give a systematic, coherent, semantically meaningful account of date and time information in daily life, something along the lines of an abstract data type. It is hard to imagine a single document satisfying both sets of expectation.
The introduction of the document needs to set the reader's expectations more clearly.
The section on “General issues” suggests that one important goal is to provide a definition in OWL of date and time information adequate for date and time data as commonly encountered on the Web and in data processing more generally. But the document fails to address a number of obvious and important questions. What requirements must such a definition meet? What possible or imaginable requirements does it NOT need to meet? Is it a goal to be able to distinguish between well-formed and ill-formed date/time descriptions? or a non-goal? Is it a goal to provide well-formulated accounts of all the essential operations on date/time data? Or is that to be left for later work? What must be done in order to provide a useful semantic account of the classes you define? What is the division of labor between this document (or more precisely: the ontology defined here) and potential users of it?
In these comments, we assume that any formal ontology of time concepts will make itself useful by
- identifying a core set of primitive notions
- relating those notions informally to real-world information by means of natural-language descriptions, so as to enable an informed reader to understand what a class instance using only those primitive notions 'means', and to formulate an appropriate class instance to capture a given intended 'meaning'; it may or may not be a goal to make the meaning and rules of interpretation clear not only to humans who have read the documentation but also to properly constructed software
- identifying a set of derived notions which can be constructed from, and defined in terms of, the primitive notions
- showing how to interpret the derived notions in terms of the primitive notions
- showing how to distinguish well-formed instances of the class from ill-formed instances, or (depending on how things are formulated) how to distinguish members of the class from other things, or both. That is, if some asks “what is the difference between an instance of class DateTimeDescription and this block of wood?” we expect the reader of the document to be able to find the answer.
- showing how to interpret / assign meaning to all well-formed instances of the class; it may or may not be a goal to avoid rules of interpretation that assign meanings to ill-formed instances
Other goals may also be important; this list claims no exclusivity.
We believe the document currently does not meet all of these expectations and thus has opportunities for improvement. If the items listed above are not in fact goals, then the document should probably identity them explicitly as non-goals, to avoid having the reader believe in error that the authors tried to satisfy them but failed. Readers might then cavil with the choice of goals for the work, but at least then the authors and the reader can argue about the same thing.
2.2. Engagement with earlier work
There is a great deal of earlier work relevant to the topic of this paper; without going at all far afield, we mention
- ISO 8601 Representations of dates and times, in the editions of 1988-06-15 and 2000-12-15, on which the date/time types of XML Schema are based
- the document Date and Time Formats, by Misha Wolf and Charles Wickstead, submitted to W3C by Reuters in 1997 (<URL:http://www.w3.org/TR/NOTE-datetime>), which proposes a profile of ISO 8601
- the date/time datatypes of XML Schema 1.0 (<URL:http://www.w3.org/TR/xmlschema-1/>) and 1.1 (<URL:http://www.w3.org/TR/xmlschema11-2/>); these are mentioned in the document, but the document provides no bibliographic reference to the relevant specifications
- the library of functions and operators on date/time values defined by XQuery 1.0 and XPath 2.0 Functions and Operators (<URL:http://www.w3.org/TR/xpath-functions/>)
- the library of functions for formatting date and time information provided in section 16.5 of XSLT 2.0 (<URL:http://www.w3.org/TR/2007/REC-xslt20-20070123/#format-date>)
The document should, we believe, refer to this related work.
More important, the document needs to engage with that other relevant work. The document's comments about the XML Schema types do not seem to reflect any real understanding of those types, their design, or the requirements of conventional information processing systems. And ISO 8601 has a great deal to teach anyone interested in working with date and time information in practice. - Related Actions Items:
- No related actions
- Related emails:
- RE: OWL-Time ready to go - except for styling issues? (from fd@w3.org on 2017-04-28)
- Re: OWL-Time ready to go - except for styling issues? (from Simon.Cox@csiro.au on 2017-04-27)
- RE: OWL-Time ready to go - except for styling issues? (from fd@w3.org on 2017-04-27)
- Re: OWL-Time ready to go - except for styling issues? (from Simon.Cox@csiro.au on 2017-04-26)
- RE: OWL-Time ready to go - except for styling issues? (from chris.little@metoffice.gov.uk on 2017-04-26)
- RE: OWL-Time ready to go - except for styling issues? (from Simon.Cox@csiro.au on 2017-04-25)
- Re: OWL-Time ready to go - except for styling issues? (from fd@w3.org on 2017-04-21)
- OWL-Time ready to go - except for styling issues? (from Simon.Cox@csiro.au on 2017-04-21)
- FW: Wide review - help needed (from Simon.Cox@csiro.au on 2017-04-21)
- OWL-Time - ISSUE-158: Introduction and goals (from Simon.Cox@csiro.au on 2017-04-21)
Related notes:
Proposed disposition - quoted from email 2017-04-21
This comment – taken from https://www.w3.org/XML/2007/qts-timeont-comments as noted - relates to the 2006 W3C Working Draft edited by Hobbs and Pan [1] . Indeed that document had a very cursory introduction under the heading ‘General issues’.
The current document has a more substantial motivation [2]. In particular, it draws attention to the fact that OWL-Time focuses particularly on predicates related to temporal topology (before, after, during, starts, etc) which are only implicit in the other encodings, though supported by XPath and XQuery functions as mentioned in the comment. Of course the XML tooling only relates to the XML Schema temporal datatypes, and not to the other representations of time supported by OWL-Time.
We hope that these modifications satisfy the concerns raised in the comment.
[1] https://www.w3.org/TR/2006/WD-owl-time-20060927/
[2] http://w3c.github.io/sdw/time/#motivation
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