Re: [CODE4LIB] CODE4LIB Digest - 12 Sep 2013 to 13 Sep 2013 (#2013-237)
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 I'd suggest that perhaps the confusion arises because This instance is (not) 'valid' according to that ontology. might be inferred from an instance and an ontology (under certain conditions), and that's the soul of what we're asking when we define constraints on the data. Perhaps OWL can be used to express conditions of validity, as long as we represent the quality valid for use in inferences. - --- A. Soroka The University of Virginia Library On Sep 13, 2013, at 11:00 PM, CODE4LIB automatic digest system wrote: Also, remember that OWL does NOT constrain your data, it constrains only the inferences that you can make about your data. OWL operates at the ontology level, not the data level. (The OWL 2 documentation makes this more clear, in my reading of it. I agree that the example you cite sure looks like a constraint on the data... it's very confusing.) -BEGIN PGP SIGNATURE- Version: GnuPG/MacGPG2 v2.0.19 (Darwin) Comment: GPGTools - http://gpgtools.org iQEcBAEBAgAGBQJSNwe2AAoJEATpPYSyaoIkwLcIAK+sMzy1XkqLStg94F2I40pe 0DepjqVhdPnaDS1Msg7pd7c7iC0L5NhCWd9BxzdvRgeMRr123zZ3EmKDSy8XZiGf uQyXlA9cOqpCxdQLj2zXv5VHrOdlsA1UAGprwhYrxOz/v3xQ7b2nXusRoZRfDlts iadvWx5DhLEb2+uVl9geteeymLIVUTzm8WnUITEE7by2HAQf9VlT9CrQSVQ21wLC hvmk47Nt8WIGyPwRh1qOhvIXLDLxD9rkBSC1G01RhzwvctDy88Tmt2Ut47ZREScP YUz/bf/qxITzX2L7tE35s2w+RUIFIFc4nJa3Xhp0wMoTAz5UYMiWIcXZ38qfGlY= =PJTS -END PGP SIGNATURE-
Re: [CODE4LIB] CODE4LIB Digest - 12 Sep 2013 to 13 Sep 2013 (#2013-237)
On 9/16/13 6:29 AM, aj...@virginia.edu wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 I'd suggest that perhaps the confusion arises because This instance is (not) 'valid' according to that ontology. might be inferred from an instance and an ontology (under certain conditions), and that's the soul of what we're asking when we define constraints on the data. Perhaps OWL can be used to express conditions of validity, as long as we represent the quality valid for use in inferences. Based on the results of the RDF Validation workshop [1], validation is being expressed today as SPARQL rules. If you express the rules in OWL then unfortunately you affect downstream re-use of your ontology, and that can create a mess for inferencing and can add a burden onto any reasoners, which are supposed to apply the OWL declarations. One participant at the workshop demonstrated a system that used the OWL constraints as constraints, but only in a closed system. I think that the use of SPARQL is superior because it does not affect the semantics of the classes and properties, only the instance data, and that means that the same properties can be validated differently for different applications or under different contexts. As an example, one community may wish to say that their metadata can have one and only one dc:title, while others may allow more than one. You do not want to constrain dc:title throughout the Web, only your own use of it. (Tom Baker and I presented a solution to this on the second day as Application Profiles [2], as defined by the DC community). kc [1] https://www.w3.org/2012/12/rdf-val/agenda [2] http://www.w3.org/2001/sw/wiki/images/e/ef/Baker-dc-abstract-model-revised.pdf - --- A. Soroka The University of Virginia Library On Sep 13, 2013, at 11:00 PM, CODE4LIB automatic digest system wrote: Also, remember that OWL does NOT constrain your data, it constrains only the inferences that you can make about your data. OWL operates at the ontology level, not the data level. (The OWL 2 documentation makes this more clear, in my reading of it. I agree that the example you cite sure looks like a constraint on the data... it's very confusing.) -BEGIN PGP SIGNATURE- Version: GnuPG/MacGPG2 v2.0.19 (Darwin) Comment: GPGTools - http://gpgtools.org iQEcBAEBAgAGBQJSNwe2AAoJEATpPYSyaoIkwLcIAK+sMzy1XkqLStg94F2I40pe 0DepjqVhdPnaDS1Msg7pd7c7iC0L5NhCWd9BxzdvRgeMRr123zZ3EmKDSy8XZiGf uQyXlA9cOqpCxdQLj2zXv5VHrOdlsA1UAGprwhYrxOz/v3xQ7b2nXusRoZRfDlts iadvWx5DhLEb2+uVl9geteeymLIVUTzm8WnUITEE7by2HAQf9VlT9CrQSVQ21wLC hvmk47Nt8WIGyPwRh1qOhvIXLDLxD9rkBSC1G01RhzwvctDy88Tmt2Ut47ZREScP YUz/bf/qxITzX2L7tE35s2w+RUIFIFc4nJa3Xhp0wMoTAz5UYMiWIcXZ38qfGlY= =PJTS -END PGP SIGNATURE- -- Karen Coyle kco...@kcoyle.net http://kcoyle.net m: 1-510-435-8234 skype: kcoylenet
Re: [CODE4LIB] CODE4LIB Digest - 12 Sep 2013 to 13 Sep 2013 (#2013-237)
Using SPARQL to validate seems like tremendous overhead. From the Gerber abstract: A total of 55 rules have been defined representing the constraints and requirements of the OA Specification and Ontology. For each rule we have defined a SPARQL query to check compliance. I hope this isn't 55 SPARQL queries per RDF resource. Europeana's review of schematron indicated what I pointed out earlier, that it confines one to using RDF/XML, which is sub-optimal in their own words. One could accept RDF in any serialization and then run it through an RDF processor, like rapper (http://librdf.org/raptor/rapper.html), into XML and then validate. Eventually, when XPath/XSLT 3 supports JSON and other non-XML data models, theoretically, schematron might then be able to validate other serializations of RDF. Ditto for XForms, which we are using to validate RDF/XML. Obviously, this is sub-optimal because our workflow doesn't yet account for non-XML data. We will probably go with the rapper intermediary process until XForms 2 is released. Ethan On Mon, Sep 16, 2013 at 10:22 AM, Karen Coyle li...@kcoyle.net wrote: On 9/16/13 6:29 AM, aj...@virginia.edu wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 I'd suggest that perhaps the confusion arises because This instance is (not) 'valid' according to that ontology. might be inferred from an instance and an ontology (under certain conditions), and that's the soul of what we're asking when we define constraints on the data. Perhaps OWL can be used to express conditions of validity, as long as we represent the quality valid for use in inferences. Based on the results of the RDF Validation workshop [1], validation is being expressed today as SPARQL rules. If you express the rules in OWL then unfortunately you affect downstream re-use of your ontology, and that can create a mess for inferencing and can add a burden onto any reasoners, which are supposed to apply the OWL declarations. One participant at the workshop demonstrated a system that used the OWL constraints as constraints, but only in a closed system. I think that the use of SPARQL is superior because it does not affect the semantics of the classes and properties, only the instance data, and that means that the same properties can be validated differently for different applications or under different contexts. As an example, one community may wish to say that their metadata can have one and only one dc:title, while others may allow more than one. You do not want to constrain dc:title throughout the Web, only your own use of it. (Tom Baker and I presented a solution to this on the second day as Application Profiles [2], as defined by the DC community). kc [1] https://www.w3.org/2012/12/**rdf-val/agendahttps://www.w3.org/2012/12/rdf-val/agenda [2] http://www.w3.org/2001/sw/**wiki/images/e/ef/Baker-dc-** abstract-model-revised.pdfhttp://www.w3.org/2001/sw/wiki/images/e/ef/Baker-dc-abstract-model-revised.pdf - --- A. Soroka The University of Virginia Library On Sep 13, 2013, at 11:00 PM, CODE4LIB automatic digest system wrote: Also, remember that OWL does NOT constrain your data, it constrains only the inferences that you can make about your data. OWL operates at the ontology level, not the data level. (The OWL 2 documentation makes this more clear, in my reading of it. I agree that the example you cite sure looks like a constraint on the data... it's very confusing.) -BEGIN PGP SIGNATURE- Version: GnuPG/MacGPG2 v2.0.19 (Darwin) Comment: GPGTools - http://gpgtools.org iQEcBAEBAgAGBQJSNwe2AAoJEATpPY**SyaoIkwLcIAK+**sMzy1XkqLStg94F2I40pe 0DepjqVhdPnaDS1Msg7pd7c7iC0L5N**hCWd9BxzdvRgeMRr123zZ3EmKDSy8X**ZiGf uQyXlA9cOqpCxdQLj2zXv5VHrOdlsA**1UAGprwhYrxOz/**v3xQ7b2nXusRoZRfDlts iadvWx5DhLEb2+**uVl9geteeymLIVUTzm8WnUITEE7by2**HAQf9VlT9CrQSVQ21wLC hvmk47Nt8WIGyPwRh1qOhvIXLDLxD9**rkBSC1G01RhzwvctDy88Tmt2Ut47ZR**EScP YUz/bf/qxITzX2L7tE35s2w+**RUIFIFc4nJa3Xhp0wMoTAz5UYMiWIc**XZ38qfGlY= =PJTS -END PGP SIGNATURE- -- Karen Coyle kco...@kcoyle.net http://kcoyle.net m: 1-510-435-8234 skype: kcoylenet
Re: [CODE4LIB] CODE4LIB Digest - 12 Sep 2013 to 13 Sep 2013 (#2013-237)
Ethan, if you are interested in dialoguing about this topic, I suspect this isn't the forum for it. I don't think that W3C has yet set up a public list on rdf validation (the meeting participants need to form an actual W3C group for that to happen, and I hope that won't take too long), but there should be one soon. It's really rather useless to keep telling *me* this, since I'm not arguing for any particular technology, just reporting what I've learned in the last few weeks about what others are doing. That is, if you are interested in having an exchange of ideas about this topic rather than repeatedly trying to convince me that what I'm saying is wrong. It's like you're trying to convince me that I really did not hear what I did. But I did hear it. Maybe all of those people are wrong; maybe you could explain to them that they are wrong. But if you care about this, then you need to be talking to them. kc On 9/16/13 7:40 AM, Ethan Gruber wrote: Using SPARQL to validate seems like tremendous overhead. From the Gerber abstract: A total of 55 rules have been defined representing the constraints and requirements of the OA Specification and Ontology. For each rule we have defined a SPARQL query to check compliance. I hope this isn't 55 SPARQL queries per RDF resource. Europeana's review of schematron indicated what I pointed out earlier, that it confines one to using RDF/XML, which is sub-optimal in their own words. One could accept RDF in any serialization and then run it through an RDF processor, like rapper (http://librdf.org/raptor/rapper.html), into XML and then validate. Eventually, when XPath/XSLT 3 supports JSON and other non-XML data models, theoretically, schematron might then be able to validate other serializations of RDF. Ditto for XForms, which we are using to validate RDF/XML. Obviously, this is sub-optimal because our workflow doesn't yet account for non-XML data. We will probably go with the rapper intermediary process until XForms 2 is released. Ethan On Mon, Sep 16, 2013 at 10:22 AM, Karen Coyle li...@kcoyle.net wrote: On 9/16/13 6:29 AM, aj...@virginia.edu wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 I'd suggest that perhaps the confusion arises because This instance is (not) 'valid' according to that ontology. might be inferred from an instance and an ontology (under certain conditions), and that's the soul of what we're asking when we define constraints on the data. Perhaps OWL can be used to express conditions of validity, as long as we represent the quality valid for use in inferences. Based on the results of the RDF Validation workshop [1], validation is being expressed today as SPARQL rules. If you express the rules in OWL then unfortunately you affect downstream re-use of your ontology, and that can create a mess for inferencing and can add a burden onto any reasoners, which are supposed to apply the OWL declarations. One participant at the workshop demonstrated a system that used the OWL constraints as constraints, but only in a closed system. I think that the use of SPARQL is superior because it does not affect the semantics of the classes and properties, only the instance data, and that means that the same properties can be validated differently for different applications or under different contexts. As an example, one community may wish to say that their metadata can have one and only one dc:title, while others may allow more than one. You do not want to constrain dc:title throughout the Web, only your own use of it. (Tom Baker and I presented a solution to this on the second day as Application Profiles [2], as defined by the DC community). kc [1] https://www.w3.org/2012/12/**rdf-val/agendahttps://www.w3.org/2012/12/rdf-val/agenda [2] http://www.w3.org/2001/sw/**wiki/images/e/ef/Baker-dc-** abstract-model-revised.pdfhttp://www.w3.org/2001/sw/wiki/images/e/ef/Baker-dc-abstract-model-revised.pdf - --- A. Soroka The University of Virginia Library On Sep 13, 2013, at 11:00 PM, CODE4LIB automatic digest system wrote: Also, remember that OWL does NOT constrain your data, it constrains only the inferences that you can make about your data. OWL operates at the ontology level, not the data level. (The OWL 2 documentation makes this more clear, in my reading of it. I agree that the example you cite sure looks like a constraint on the data... it's very confusing.) -BEGIN PGP SIGNATURE- Version: GnuPG/MacGPG2 v2.0.19 (Darwin) Comment: GPGTools - http://gpgtools.org iQEcBAEBAgAGBQJSNwe2AAoJEATpPY**SyaoIkwLcIAK+**sMzy1XkqLStg94F2I40pe 0DepjqVhdPnaDS1Msg7pd7c7iC0L5N**hCWd9BxzdvRgeMRr123zZ3EmKDSy8X**ZiGf uQyXlA9cOqpCxdQLj2zXv5VHrOdlsA**1UAGprwhYrxOz/**v3xQ7b2nXusRoZRfDlts iadvWx5DhLEb2+**uVl9geteeymLIVUTzm8WnUITEE7by2**HAQf9VlT9CrQSVQ21wLC hvmk47Nt8WIGyPwRh1qOhvIXLDLxD9**rkBSC1G01RhzwvctDy88Tmt2Ut47ZR**EScP YUz/bf/qxITzX2L7tE35s2w+**RUIFIFc4nJa3Xhp0wMoTAz5UYMiWIc**XZ38qfGlY= =PJTS -END PGP SIGNATURE- -- Karen Coyle
