Absolute time in dateTime format (w3c#389)

* updates

* include VIAMEE results

* absolute time, implied UTC

* date-time


Changed to require conformance with RFC3339, which makes timezone offset mandatory.  Ideally we would get rid of dateTime altogether, follow up in w3c#390

index.html

@@ -1168,7 +1168,7 @@ <h3>Information Model</h3>
                 To Do: Formal definition of information contained in a directory and its organization.
                 </p>
 -->
-
+                <p>
                 As shown in [[[#exploration-class-diagram]]], 
                 the <a>Thing Description Directory</a> can contain zero or more <a>TDs</a>.
                 For every TD, the directory maintains additional metadata
@@ -1178,9 +1178,11 @@ <h3>Information Model</h3>
                 [[[#exploration-directory-anonymous-td]]].
                 A <a>TD</a> that embeds such additional metadata as part of the
                 interaction with the directory is called an <a>Enriched TD</a>.
+                </p>
 
                 <section id="exploration-directory-registration-info" class="normative">
                     <h4>Registration Information</h4>
+                    <p>
                     The ontology of a <a>TD</a> in the Discovery context was
                     introduced in [[[#discovery-class-diagram-ontology]]].
                     The `RegistrationInformation` class is associated with <a>TDs</a> that are
@@ -1193,6 +1195,20 @@ <h4>Registration Information</h4>
                     In this table,
                     client refers to the producer or consumer of a <a>TD</a> and server refers to
                     the <a>Thing Description Directory</a>.
+                    </p>
+                    <p>
+                    <span class="rfc2119-assertion" id="tdd-absolute-time">Whenever an absolute time is expressed
+                    using <a href="https://www.w3.org/TR/2012/REC-xmlschema11-2-20120405/#dateTime">dateTime</a> 
+                    it MUST be interpreted as date-time as specified in [[RFC3339]].</span>
+                    Specifically, the timezone offset is not optional.
+                    </p>
+                    <p class="ednote" title="dateTime vs. date-time">We should update the ontology to 
+                    only use date-time and RFC3339 and
+                    not this odd combination of dateTime and date-time, 
+                    but this should also be resolved in the TD specification.
+                    However, we would need a new SHACL shape with this additional restriction.
+                    </p>
+
                     <table class="def">
                         <thead>
                             <tr>
@@ -1207,7 +1223,7 @@ <h4>Registration Information</h4>
                             <tr class="rfc2119-table-assertion" id="tdd-registrationinfo-vocab-created">
                                 <td><code>created</code></td>
                                 <td>
-                                    Provides information when the TD instance was
+                                    Provides the absolute time when the TD instance was
                                     created inside the directory.
                                     <p>
                                         This MAY be set by the directory and returned to consumers.
@@ -1220,7 +1236,7 @@ <h4>Registration Information</h4>
                             <tr class="rfc2119-table-assertion" id="tdd-registrationinfo-vocab-modified">
                                 <td><code>modified</code></td>
                                 <td>
-                                    Provides information when the TD instance was
+                                    Provides the absolute time when the TD instance was
                                     last modified inside the directory.
                                     <p>
                                         This MAY be set by the directory and returned to consumers.
@@ -1233,7 +1249,7 @@ <h4>Registration Information</h4>
                             <tr class="rfc2119-table-assertion" id="tdd-registrationinfo-vocab-expires">
                                 <td><code>expires</code></td>
                                 <td>
-                                    Provides the absolute time for when the TD instance registration expires.
+                                    Provides the absolute time when the TD instance registration expires.
                                     <p>
                                         The producer MAY set this to indicate the absolute expiry time
                                         during the registration.
@@ -1269,7 +1285,7 @@ <h4>Registration Information</h4>
                             <tr class="rfc2119-table-assertion" id="tdd-registrationinfo-vocab-retrieved">
                                 <td><code>retrieved</code></td>
                                 <td>
-                                    The time at which the TD was retrieved from the server.
+                                    The absolute time at which the TD was retrieved from the server.
                                     <p>
                                         This is useful for clients that intend to process other absolute timestamps but
                                         do not have an internal clock or other means of acquiring the current time.