- From: Maxime Lefrançois <maxime.lefrancois@emse.fr>
- Date: Tue, 07 Feb 2017 21:48:07 +0000
- To: Rob Atkinson <rob@metalinkage.com.au>, Armin Haller <armin.haller@anu.edu.au>, Kerry Taylor <kerry.taylor@anu.edu.au>, "public-sdw-wg@w3.org" <public-sdw-wg@w3.org>, "Simon.Cox@csiro.au" <Simon.Cox@csiro.au>
- Message-ID: <CALsPASXYxras_GVaOFFedAtR2eQd-xaAFxgTRFx_Fo=6BnpNbg@mail.gmail.com>
True. So with respect to ssnx.ttl in the proposal I just made, at line 82 in https://github.com/w3c/sdw/pull/536/commits/9c3f1cf43d4b22d1b34da630a734608aca02517f would everyone agree that it should be updated to: oldssn:Property owl:equivalentClass sosa:ObservableProperty ; and that ssn:Property which is a new term defined in ssn: now also includes actionable properties and non-observable properties ? Best, Maxime Le mar. 7 févr. 2017 à 22:09, Rob Atkinson <rob@metalinkage.com.au> a écrit : > NB If the ssn namespace is updated, then the backwards compatibility issue > here is spurious AFAICT > Equivalence axioms would be required to use the legacy SSN, and these can > handle name changes. > > > On Wed, 8 Feb 2017 at 07:48 Armin Haller <armin.haller@anu.edu.au> wrote: > > This is a compromise I thought we were heading to yesterday. > > > > +1 from me for this approach on solving the observable property issue. > > > > *From: *Kerry Taylor <kerry.taylor@anu.edu.au> > *Date: *Wednesday, 8 February 2017 at 1:54 am > *To: *Rob Atkinson <rob@metalinkage.com.au>, "public-sdw-wg@w3.org" < > public-sdw-wg@w3.org>, "Simon.Cox@csiro.au" <Simon.Cox@csiro.au>, Maxime > Lefrançois <maxime.lefrancois@emse.fr> > *Subject: *RE: Proposals (was Re: Architecture of SOSA/SSN integration) : > issue-87 only: FIRM PROPOSAL > *Resent-From: *<public-sdw-wg@w3.org> > *Resent-Date: *Wednesday, 8 February 2017 at 1:55 am > > > > Rob, Simon, Armin , Maxime and all, > > Don’t get me wrong – I totally agree that ‘a distinction is meaningless”. Given > (a) the existence of an OGC standard (O&M) and (b) the long time practice > in SSN (whcih was only because of (a)) , “Property” really does seem the > sensible default. And its easier to say! > > > > However, if indeed ‘Property" was too ambiguous” , and recognising the > painful double-meaning in RDF, and subject to something sensible happening > around here for Actuators, and noting that ‘Observable property’ seems to > be entirely equivalent in meaning to “Property” in anyone’s use of it that > I can see, > > and following up on Armin’s suggestion, > > > > We could > > (1) use Observable property in sosa > > (2) use “observable property” in ssn in the restriction context (as in > sosa) of a property that is the observedproperty of an observation > > (3) in ssn assert observableproperty subclassOf Property > > (4) continue to use Property for all those other things that ssn uses it > for now, such as the superclass of “survivalrange”. > > (5) leave it to a user if they want to assert that those other properties > (e.g. survival range) are also subclasses of “observableproperty” incase > they want to observe it > > (6) fix rdfs:comments accordingly > > > > > > This is entirely consistent with my integration proposal but its is MUCH > harder than just sticking to “Property”. > https://www.w3.org/2015/spatial/wiki/Proposals_for_rewriting_SSN#Compromise_Proposal_6_made_by_Kerry_January_2017 > . And it a alows sosa-ssn interoperability perfectly (ie all your > observational instances still interoperate both directions). And I can’t > see the dul alignment being affected. > > > > Except it is NOT backwardly compatible for ssn users, who use “property” > for things that are observed. Ideas? Such users could add > “observableproperty equivalentclass Property” I suppose? We could put > this in ssnx ontology? Is it just much too late at night for me to see if > there is no problem here anyway – mihgt have to have another look at > observation to be sure. Maybe its ok without the equivalent assertion… > > > > Ø Btw: “But it is clear that some properties definitely are not > “observable” in any normal sense (e.g. “name”, “owner”, “creator”) and > could never be associated with sensing procedures or instruments. “ > > I think that is in direct contradiciotn with our own definitions of > “observable property’, but I don’t care….see “Assertion’ type below. Surely > a human sensor can observe the price of an item in a shop? Or the name of a > person from a nametag? Or the creator of a piece of art by studying its > style? So can an image processing sensor. Or maybe a barcode scanner. But > it is not important. > > > > Change of topic… > > Ø On subclassing: why is it that you dislike having these in alignments? > Is there a principled reason for this application, or does subclassing > introduce some general difficulty that I’m not familiar with? > > Lots of reasons. *But the most important one is the bi-directional > interoperability*. So you can take a ssn full instance , let a reasoner > run for all the instances, throw away any non-sosa terms and voila you have > a proper sosa instance. E.g. if you have a sosa:observation subclass of > ssn:observation you cannot do this. OTOH you can take a sosa instance, and > it is a fully formed ssn instance just start decorating it as it is with > any extra ssn properties you want. E.g. if you have a ssn:observation > subclass of sosa:observation you cannot do this. > > Ok equivalentclass can do that right —but that ‘s inelegant for other > reasons. > > And its not an “alignment” --- what an ugly design to make an ontology > ”align” with its simple core! Truly bizarre. > > And what do we think we are doing to our poor users forcing them to use > the same term with two different prefixes in the same ontology? Whoever > would force that on anyone???? How are they supposed to know what they > are to do – even if they actually notice there is a difference before they > break everything. > > I should take on the task of formalising this property - I am quite sure > I did not invent it --- it is really important to me or else how can sosa > make any sense as a core of ssn?– and Jano’s original modularisation > proposal seems to have this property anyway. Where did it all go wrong? > > *So … will you help?* Is there anyone out there that can understand what > I am saying yet? Maxime seems to get it!! I absolutely cannot do this > alone. > > > > Kerry > > > > *From:* Rob Atkinson [mailto:rob@metalinkage.com.au] > *Sent:* Tuesday, 7 February 2017 6:07 PM > *To:* Armin Haller <armin.haller@anu.edu.au>; Simon.Cox@csiro.au; Kerry > Taylor <kerry.taylor@anu.edu.au>; janowicz@ucsb.edu; > maxime.lefrancois@emse.fr; public-sdw-wg@w3.org > *Subject:* Re: Proposals (was Re: Architecture of SOSA/SSN integration) : > issue-87 only > > > > FWIW, my experience of people using O&M is that "Property" was too > ambiguous and people used it in rather arbitrary fashion - strictly is > should relate to a property of the feature being observed, but with > intermediate sampling features, and in general the model of the observed > feature not being available formally this was generally too hard to unravel > - and people tend to use it as a surrogate for the procedure, or a > generalised classification of the subject, or just their cat's name or > something. > > > > So I would suggest the current long-hand name of "ObservableProperty" is > helpful - and its an opportunity to educate that "observations" may be > performed by physical sensors or via models. IMHO there are actually a > chain of scientific models in play for every physical sensor, and its all > the same thing and a distinction is meaningless. Sensors are a way to give > a shorthand identifier to part of such a chain, because the sensor > construction makes that chain immutable. > > > > Rob > > > > > > > > > > > > On Tue, 7 Feb 2017 at 13:44 Armin Haller <armin.haller@anu.edu.au> wrote: > > Kerry, you seem to be ok with recasting uses of Property in SSN, as below. > I note here that it does not have to be a recasting of **all**, only > where appropriate. There are already several other subclasses of Property > in SSN, e.g. SurvivableProperty, OperatingProperty etc. which seem to be > introduced in SSN to make it easier for the user of the ontology to know > what is meant with “Property” in a specific use of the class. The same > would apply to ObservableProperty that is introduced in the core, making it > easier for the user to know what this class means, in the absence of OWL > axioms that give the informed user a clue on its intended use. > > > > > > *From: *"Simon.Cox@csiro.au" <Simon.Cox@csiro.au> > *Date: *Tuesday, 7 February 2017 at 1:29 pm > *To: *Kerry Taylor <kerry.taylor@anu.edu.au>, Armin Haller < > armin.haller@anu.edu.au>, "janowicz@ucsb.edu" <janowicz@ucsb.edu>, " > maxime.lefrancois@emse.fr" <maxime.lefrancois@emse.fr>, " > public-sdw-wg@w3.org" <public-sdw-wg@w3.org> > > > *Subject: *RE: Proposals (was Re: Architecture of SOSA/SSN integration) : > issue-87 only > > > > Thanks for exploring this Kerry. > > > > I agree that at least some ‘derivation’ processes fall into our broad > definition of ‘sensing’ and ‘observation’. > > Note that I did hedge the subclassing with the statement > > “These are not necessarily disjoint …”. > > But it is clear that some properties definitely are not “observable” in > any normal sense (e.g. “name”, “owner”, “creator”) and could never be > associated with sensing procedures or instruments. > > > > So there is a spectrum, but I would suggest that in the SSN layer at least > we really are only interested in Observable Properties, and it is likely > that inventories of these could be usefully assembled, alongside catalogues > of sensors. And that it is useful to keep these clear of the non-observable > properties. > > > > On subclassing: why is it that you dislike having these in alignments? Is > there a principled reason for this application, or does subclassing > introduce some general difficulty that I’m not familiar with? > > > > Simon > > > > *From:* Kerry Taylor [mailto:kerry.taylor@anu.edu.au] > *Sent:* Tuesday, 7 February, 2017 12:37 > *To:* Armin Haller <armin.haller@anu.edu.au>; janowicz@ucsb.edu; Maxime > Lefrançois <maxime.lefrancois@emse.fr>; Cox, Simon (L&W, Clayton) < > Simon.Cox@csiro.au>; public-sdw-wg@w3.org > *Subject:* RE: Proposals (was Re: Architecture of SOSA/SSN integration) : > issue-87 only > > > > This subclass means that ssn instance data does not become sosa-compliant > instance data (I would love to have that if you take all the instances of > all the core terms out of an ssn full instance you also have a usable sosa > instance. I know this is asking a lot… but I want bi-directional > interoperability which is implied by my proposal for integration. I should > have spelled this out earlier – and I suppose it needs some formalisation > to be useful. > > > > In this case if we really need “ObservableProperty)” ( and my own view is > that this is just silly vocabulary, and I’d much rather keep “property” for > O&M compliance anyway, nevertheless I can live with it) I would like to > check again whether **all** SSN uses of Property could be recast as > “Observable property”. They are certainly not all “Observed” properties, > but given an explanation of what distinguishes “observable” from others > kind of properties I would look at the implications. > > > > OTOH looking at Simon’s ISO list : > > >- Observation > > >- Assertion (e.g. name, price) > > >- Derivation (e.g. classifications based on combinations of > observed properties) > > >- Inheritance/instantiation (e.g. where a property value is > assumed on the basis of class membership) > > >These are not necessarily disjoint, and it is likely that observable > properties are the most interesting (depending on you epistemological > viewpoint) >but it is useful to recognize that observable properties are a > distinct class. > > It is very clear that in sosa we do **not** want “observable properties” > because we have sensors that are computational simulations making > observations by ‘Derivation” so this may not be Observable at all. And > surely ours can also can be “Assertion” (in the case the sensor is a human, > for example). Maybe even inheritance/instantiation too. For the latter if > we want to observe that some animal instance (such as animals caught in > my trap) has the property of being a member of some species (e.g. “Homo > Sapiens” ) on the basis of class membership --Why not? Why should we > prohibit that property being observed? > > > > So this is a really strong reason why we should stick to “Property” > surely! If “Observable property” in this ISO vocab means anything at all > then it must be distinc t from the union “Property” and so “Property” is > what we need! > > > > > > > > I really dislike subclass alignments….and I dislike equivalentclass > almost as much, wherever they actually sit. I way prefer using the same > terms throughout, > > Which I tried to show in my proposal. > > > > Just catching up here so maybe I missed something. > > > > Thoughts? > > -Kerry > > > > > > > > > > > > > > *From:* Armin Haller > *Sent:* Tuesday, 7 February 2017 11:49 AM > *To:* janowicz@ucsb.edu; Maxime Lefrançois <maxime.lefrancois@emse.fr>; > Simon.Cox@csiro.au; Kerry Taylor <kerry.taylor@anu.edu.au>; > public-sdw-wg@w3.org > *Subject:* Re: Proposals (was Re: Architecture of SOSA/SSN integration) : > issue-87 only > > > > The sub-class relation would only be introduced in SSN not SOSA. I should > have been more explicit in the second dot-point. The third dot-point means > to say that. > > > > *From: *Krzysztof Janowicz <janowicz@ucsb.edu> > *Reply-To: *"janowicz@ucsb.edu" <janowicz@ucsb.edu> > *Date: *Tuesday, 7 February 2017 at 11:44 am > *To: *Armin Haller <armin.haller@anu.edu.au>, Maxime Lefrançois < > maxime.lefrancois@emse.fr>, "Simon.Cox@csiro.au" <Simon.Cox@csiro.au>, > Kerry Taylor <kerry.taylor@anu.edu.au>, "public-sdw-wg@w3.org" < > public-sdw-wg@w3.org> > *Subject: *Re: Proposals (was Re: Architecture of SOSA/SSN integration) : > issue-87 only > > > > Not sure, whether I am fully understanding this. > > - ObservableProperty is a subclass of ssn:Property > > > This would violate one of our design principles, namely that SOSA does not > make use of SSN. > > > On 02/06/2017 04:41 PM, Armin Haller wrote: > > It looks like we have a proposal here to resolve issue 87: > https://www.w3.org/2015/spatial/track/issues/87 > > > > Please let me try to restate what was proposed: > > > > - ObservableProperty is introduced in SOSA (as is currently > implemented in: https://github.com/w3c/sdw/blob/gh-pages/ssn/rdf/sosa.ttl) > > - ObservableProperty is a subclass of ssn:Property > > - ObservableProperty is introduced in SSN as well and the > subclass relation to ssn:Property is stated within > > > > That leaves the door open to have another property in SSN (and) SOSA > concerned with ActuableProperties. > > > > This should also mean that SSN instances are SOSA instances, since no > axioms in SOSA are violated. > > > > Is my understanding correct? > > > > > > *From: *Maxime Lefrançois <maxime.lefrancois@emse.fr> > <maxime.lefrancois@emse.fr> > *Date: *Tuesday, 7 February 2017 at 10:14 am > *To: *"Simon.Cox@csiro.au" <Simon.Cox@csiro.au> <Simon.Cox@csiro.au> > <Simon.Cox@csiro.au>, "janowicz@ucsb.edu" <janowicz@ucsb.edu> > <janowicz@ucsb.edu> <janowicz@ucsb.edu>, Kerry Taylor > <kerry.taylor@anu.edu.au> <kerry.taylor@anu.edu.au>, > "public-sdw-wg@w3.org" <public-sdw-wg@w3.org> <public-sdw-wg@w3.org> > <public-sdw-wg@w3.org> > *Subject: *Re: Proposals (was Re: Architecture of SOSA/SSN integration) : > issue-87 only > *Resent-From: *<public-sdw-wg@w3.org> <public-sdw-wg@w3.org> > *Resent-Date: *Tuesday, 7 February 2017 at 10:15 am > > > > Yes indeed, this is what I meant. Thanks. > > > > Le lun. 6 févr. 2017 à 23:50, <Simon.Cox@csiro.au> <Simon.Cox@csiro.au> a > écrit : > > Ø it appears very strange to me to state that a ssn:property is a sub > property of a sosa:ObservableProperty > > Ø This is what can be read at [1] > > > > Assuming you mean “it appears very strange to me to state that a > ssn:Property is a sub class of a sosa:ObservableProperty” then I agree. That > looks like my error. > > > > Simon > > > > *From:* Maxime Lefrançois [mailto:maxime.lefrancois@emse.fr] > *Sent:* Monday, 6 February, 2017 17:55 > *To:* janowicz@ucsb.edu; Cox, Simon (L&W, Clayton) <Simon.Cox@csiro.au> > <Simon.Cox@csiro.au>; kerry.taylor@anu.edu.au; public-sdw-wg@w3.org > > > *Subject:* Re: Proposals (was Re: Architecture of SOSA/SSN integration) : > issue-87 only > > > > Ø And it appears very strange to me to state that an observable property > is a sub property of a property. > > That was a slip of the tongue, I meant: > > > > it appears very strange to me to state that a ssn:property is a sub > property of a sosa:ObservableProperty > > This is what can be read at [1] and is also what I would model when Phil > says: > > >>> Looking at the two definitions, there are differences but they look > > >>> very minor to my eyes with sosa:ObservableProperty looking slightly > > >>> more general, so, again, I'd delete ssn:Property. > > > > [1] - https://github.com/w3c/sdw/blob/gh-pages/ssn/rdf/ssn-sosa.ttl > > > > but anyways, +1 in favour of your arguments, and I propose that: > > > > - we update sosa-ssn.ttl to reflect what we all agree on; > > - we also consider either to add sosa:ActuableProperty, or roll back to > just sosa:Property. > > > > Kind regards, > > Maxime > > > > Not strange actually – not all properties are observable. In the revision > of ISO 19109:2015 we distinguished between > > - Observation > > - Assertion (e.g. name, price) > > - Derivation (e.g. classifications based on combinations of > observed properties) > > - Inheritance/instantiation (e.g. where a property value is > assumed on the basis of class membership) > > These are not necessarily disjoint, and it is likely that observable > properties are the most interesting (depending on you epistemological > viewpoint) but it is useful to recognize that observable properties are a > distinct class. > > > > Yes, not strange at all. I agree with all of Simon's arguments and we also > made them in one of our telco's half a year ago. > > > > > On 02/05/2017 04:57 PM, Simon.Cox@csiro.au wrote: > > Ø And it appears very strange to me to state that an observable property > is a sub property of a property. > > > > Not strange actually – not all properties are observable. In the revision > of ISO 19109:2015 we distinguished between > > - Observation > > - Assertion (e.g. name, price) > > - Derivation (e.g. classifications based on combinations of > observed properties) > > - Inheritance/instantiation (e.g. where a property value is > assumed on the basis of class membership) > > These are not necessarily disjoint, and it is likely that observable > properties are the most interesting (depending on you epistemological > viewpoint) but it is useful to recognize that observable properties are a > distinct class. > > > > Simon > > > > *From:* Maxime Lefrançois [mailto:maxime.lefrancois@emse.fr > <maxime.lefrancois@emse.fr>] > *Sent:* Monday, 6 February, 2017 00:22 > *To:* Kerry Taylor <kerry.taylor@anu.edu.au> <kerry.taylor@anu.edu.au>; > SDW WG Public List <public-sdw-wg@w3.org> <public-sdw-wg@w3.org> > *Subject:* Re: Proposals (was Re: Architecture of SOSA/SSN integration) : > issue-87 only > > > > +1 for Kerry's arguments. > > > > And it appears very strange to me to state that an observable property is > a sub property of a property. > > > > I just changed to sosa:Property instead of sosa:ObservableProperty in the > proposal I am currently working on. > > + add relations and classes that are missing > > > > best, > > Maximle > > Le dim. 5 févr. 2017 à 13:44, Kerry Taylor <kerry.taylor@anu.edu.au> a > écrit : > > > > PhilA has said > > >>> Looking at the two definitions, there are differences but they look > > >>> very minor to my eyes with sosa:ObservableProperty looking slightly > > >>> more general, so, again, I'd delete ssn:Property. > > > > This is issue-87. As you can see by my analysis last November in the > tracker https://www.w3.org/2015/spatial/track/issues/87 , > > > > (1). A sosa: Observable Property is NOT an O&M property. The O&M standard > has no such term. > > > > (2) The ssn:Property has the same intended meaning as an an O&M Property (and, yes it is an O&M “Property”) and this is explicit by the annotation within ssn “<dc:source> skos:exactMatch 'property' [O&M] http://www.opengeospatial.org/standards/om </dc:source>” > > > > (3) What is shown in the mapping table is not the complete annotation for > ssn:Property – just an extract. However that very paragraph deserves > improvement. > > > > (4) ssn:Property is used in other places throughout ssn that have nothing > to do with the narrow context associated with Observation as it is used in > SOSA. > > In particular, nothing to do with a > > > > (5) ssn:Property cannot be deleted --- many, many things will break. Nor > can it be replaced by sosa:ObservableProperty (see 4). Maybe it is > possible to say sosa:Property rdfs:SubclassOf ssn:Property but this has > its problems too (ssn instances would not be sosa instances). A more > sophisticated workaround is required if we head that direction. > > > > (6) ssn users know it as “Property” . So do O&M users. Why change, who are > we serving? > > > > (6) OTOH a simple name change in sosa to “Property” and some > clarification on the rdfs:comments in both places would work – and then ssn > and sosa can use the very same term. This is the essence of my proposal on > the wiki as a pattern to solve all these many problems. > https://www.w3.org/2015/spatial/wiki/Proposals_for_rewriting_SSN#Compromise_Proposal_6_made_by_Kerry_January_2017 > > In this case the rdfs:comment suggested by Armin looks very close but I > prefer abbreviated as follows (due to (4) ) “An observable quality of a > real world phenomena (thing, person, event, etc.) “ or here is another idea > that I propose “An observable quality of a real world phenomena (object, > person, or event), typically a FeatureOfInterest” . That works well in > the context for my proposal that also shows how to use it in the simple > core. > > > > > > -Kerry > > > > > > Dr Kerry Taylor > > Associate Professor (Data Science) > > Research School of Computer Science > > ANU College of Engineering and Computer Science > > Canberra ACT 2601 Australia > > +61 2 6125 8560 <+61%202%206125%208560> > > > > > > > > -- > > Krzysztof Janowicz > > > > Geography Department, University of California, Santa Barbara > > 4830 Ellison Hall, Santa Barbara, CA 93106-4060 > > > > Email: jano@geog.ucsb.edu > > Webpage: http://geog.ucsb.edu/~jano/ > > Semantic Web Journal: http://www.semantic-web-journal.net > > > > > > > > -- > > Krzysztof Janowicz > > > > Geography Department, University of California, Santa Barbara > > 4830 Ellison Hall, Santa Barbara, CA 93106-4060 > > > > Email: jano@geog.ucsb.edu > > Webpage: http://geog.ucsb.edu/~jano/ > > Semantic Web Journal: http://www.semantic-web-journal.net > >
Received on Tuesday, 7 February 2017 21:48:54 UTC