--- a/model/working-copy/towards-wd4.html Fri Feb 10 10:17:44 2012 +0000
+++ b/model/working-copy/towards-wd4.html Fri Feb 10 17:33:50 2012 +0000
@@ -56,6 +56,13 @@
"2011, Working Draft. "+
"URL: <a href=\"http://www.w3.org/TR/prov-o/\">http://www.w3.org/TR/prov-o/</a>",
+
+ "PROV-DM-CONSTRAINTS":
+ "Luc Moreau and Paolo Missier (eds.) ... "+
+ "<a href=\"http://www.w3.org/TR/prov-dm-constraints/\"><cite>PROV-DM Constraints</cite></a>. "+
+ "2011, Working Draft. "+
+ "URL: <a href=\"http://www.w3.org/TR/prov-dm-constraints/\">http://www.w3.org/TR/prov-dm-constraints/</a>",
+
"PROV-AQ":
"Graham Klyne and Paul Groth (eds.) Luc Moreau, Olaf Hartig, Yogesh Simmhan, James Meyers, Timothy Lebo, Khalid Belhajjame, and Simon Miles "+
"<a href=\"http://www.w3.org/TR/prov-aq/\"><cite>Provenance Access and Query</cite></a>. "+
@@ -504,7 +511,7 @@
</section>
<!-- </section> -->
-<section id="section-example">
+<section id="prov-dm-example">
<h2>Example</h2>
@@ -592,11 +599,18 @@
</figure>
</div>
+<div class='note'>
+Illustration to be hand crafted instead of being generated automatically. It's important to adopt a common style for all illustrations across all PROV documents.
+</div>
+
+
<p> This simple example has shown a variety of PROV-DM constructs, such as Entity, Agent, Activity, Usage, Generation, Derivation, and ActivityAssociation. In this example, it happens that all entities were already Web resources, with readily available URIs, which we used. We note that some of the resources are public, whereas others have restricted access: provenance statements only make use of their identifiers. When identifiers do not pre-exist, e.g. for activities, then they can be minted, for instance <span class="name">ex:pub2</span>, occuring in the namespace identified by prefix <span class="name">ex</span>.</p>
<div class='note'>
-Illustration to be hand crafted instead of being generated automatically. It's important to adopt a common style for all illustrations across all PROV documents.
+Need to say something about this example, where all urls are well behaved.
</div>
+
+
</section>
<section id="section-example-b">
<h3>The Authors View</h3>
@@ -2022,21 +2036,46 @@
<section id="FurtherConsiderations">
-<h4>Further Considerations</h4>
-
-<div class='note'>
-TODO: gives a high level taster for part II
-</div>
+<h4>Data Model Constraints</h4>
+
<ul>
-<li> Ordering Constraints
-
-<li> Attributes, fixed values over some intervals.
-
-<li> Provenance of Provenance and Provenance from Multiple Perspectives/Providers
-
-<li>Bundles, containers</li>
+<li>This specification defines PROV-DM, a data model that allows
+descriptions of the people, institutions, entities, and activities,
+involved in producing, influencing, or delivering a piece of data or a
+thing to be expressed. However, with this data model, it is also possible to compose
+descriptions that would not make sense: for instance, one could
+express that an entity was used before it was generated, or that the
+activity that generated an entity began its existence after the entity
+generation. A set of constraints have been defined for PROV-DM and
+can be found in a companion specification [[PROV-DM-CONSTRAINTS]].
+They can be used by asserters as a guideline for composing provenance descriptions and
+by implementers of reasoning engines. </li>
+
+
+
+<li>
+<p> The example of <a href="#prov-dm-example">section 3</a> contains identifiers such as <span class="name"><a href="http://www.w3.org/TR/2011/WD-prov-dm-20111215">tr:WD-prov-dm-20111215</a></span>, which denotes a specific version of a technical report. On the other hand, a URI such as <a href="http://www.w3.org/TR/prov-dm/">http://www.w3.org/TR/prov-dm/</a> points to the latest version of a document. In such circumstances, one needs to be cautious about provenance descriptions for such a document, to ensure that they remain valid as denoted resources change. </p>
+
+<p>To this end, PROV-DM allows asserters to describe "<em>partial states</em>" of entities by means of attributes and associated values. Some further constraints apply to the use of these attributes, since the values associated with them are expected to remain unchanged for some period of time. The constraints associated to attributes are also specified in the companion specification [[PROV-DM-CONSTRAINTS]].</p>
+</p>
+
+
+</li>
+
+
+<li>It is assumed that some mechanism exists by which a set of provenance descriptions can be bundled up and named. Such a mechanism is considered as not mature for standardization, and is outside the scope of PROV-DM. Such a mechanism could be implemented in various, for instance, by:
+<ul>
+<li> packaging up a set of descriptions and exposing them as a Web resource;</li>
+<li> relying on specific serializations to name bundles of descriptions;</li>
+<li> using the idea of a service that is capable of associating provenance descriptions to whom they are attributed to.</li>
+</ul>
+<p>Even though a mechanism for packaging up provenance descriptions and naming them is not part of PROV-DM, it is crucial to the PROV approach. Indeed, it allows multiple provenance perspectives to be provided for a given entity. It is also the mechanism by which provenance of provenance can be expressed. Such a named blundle is being referred to as an <dfn>account</dfn> and is regarded as an <a title="concept-accountEntity">AccountEntity</a> so that its provenance can be expressed. The notion of account is specified in the companion specification [[PROV-DM-CONSTRAINTS]], as well as constraint that <dfn>structurally well-formed</dfn> descriptions are expected to satisfy.
+With these constraints, further inferences can be made, because records are more precise, and therefore, richer.</p>
+</li>
+
+
</ul>