--- a/model/ProvenanceModel.html Fri Dec 16 13:53:14 2011 +0000
+++ b/model/ProvenanceModel.html Mon Dec 19 08:48:41 2011 +0000
@@ -374,7 +374,7 @@
relation with respect to other similar starts. </p>
-<p>Hence, in our conceptualization of the world, an instantaneous event, or <dfn id="dfn-event">event</dfn> for short, happens in the world and marks a change in the world, in its activities and in its entities.
+<p>Hence, in our conceptualization of the world, an <em>instantaneous event</em>, or <dfn id="dfn-event">event</dfn> for short, happens in the world and marks a change in the world, in its activities and in its entities.
The term "event" is commonly used in process algebra with a similar meaning. For instance, in CSP [[CSP]], events represent communications or interactions; they are assumed to be atomic and instantaneous.</p>
@@ -383,17 +383,17 @@
<section>
<h4>Types of Events</h4>
-<p>Four kinds of events underpin the PROV-DM data model. The <strong>activity start</strong> and <strong>activity end</strong> events demarcate the beginning and the end of activities, respectively. The <strong>entity generation</strong> and <strong>entity usage</strong> events demarcate the characterization interval for entities. More specifically:
+<p>Four kinds of <a title="event">instantaneous events</a> underpin the PROV-DM data model. The <strong>activity start</strong> and <strong>activity end</strong> events demarcate the beginning and the end of activities, respectively. The <strong>entity generation</strong> and <strong>entity usage</strong> events demarcate the characterization interval for entities. More specifically:
</p>
-<p>An <dfn id="dfn-generation-event">entity generation event</dfn> is the <a>event</a> that marks the final instant of an entity's creation timespan, after which it becomes available for use.</p>
-
-<p>An <dfn id="dfn-usage-event">entity usage event</dfn> is the <a>event</a> that marks the first instant of an entity's consumption timespan by an activity.</p>
-
-<p>An <dfn id="dfn-start-event">activity start event</dfn> is the <a>event</a> that marks the instant an activity starts.</p>
-
-<p>An <dfn id="dfn-end-event">activity end event</dfn> is the <a>event</a> that marks the instant an activity ends.</p>
+<p>An <dfn id="dfn-generation-event">entity generation event</dfn> is the <a title="event">instantaneous event</a> that marks the final instant of an entity's creation timespan, after which it becomes available for use.</p>
+
+<p>An <dfn id="dfn-usage-event">entity usage event</dfn> is the <a title="event">instantaneous event</a> that marks the first instant of an entity's consumption timespan by an activity.</p>
+
+<p>An <dfn id="dfn-start-event">activity start event</dfn> is the <a title="event">instantaneous event</a> that marks the instant an activity starts.</p>
+
+<p>An <dfn id="dfn-end-event">activity end event</dfn> is the <a title="event">instantaneous event</a> that marks the instant an activity ends.</p>
</section>
@@ -407,14 +407,14 @@
<p>Specifically, <dfn id="dfn-follows">follows</dfn> is a partial
-order between <a title="event">events</a>, indicating that an <a>event</a> occurs after another.
+order between <a title="event">instantaneous events</a>, indicating that an <a title="event">instantaneous event</a> occurs after another.
For symmetry, <dfn id="dfn-precedes">precedes</dfn> is defined as
the inverse of follows. </p>
<p> How such partial order is realized in practice is beyond the scope
of this specification. This specification only assumes that
-each <a>event</a> can be mapped to an instant in some form of
+each <a title="event">instantaneous event</a> can be mapped to an instant in some form of
timeline. The actual mapping is not in scope of this
specification. Likewise, whether this timeline is formed of a single
global timeline or whether it consists of multiple Lamport's style
@@ -425,19 +425,19 @@
<p>This specification introduces a set of "temporal interpretation"
-rules allowing to derive <a>event</a> ordering constraints from
+rules allowing to derive <a title="event">instantaneous event</a> ordering constraints from
provenance records. According to such temporal interpretation,
provenance records MUST satisfy such constraints. We note that the
actual verification of such temporal constraints is also outside the
scope of this specification. </p>
<p>PROV-DM also allows for time observations to be inserted in specific
-provenance records, for each recognized <a>event</a> introduced
+provenance records, for each recognized <a title="event">instantaneous event</a> introduced
in this specification. The presence of a time observation for a
-given <a>event</a> fixes the mapping of this <a>event</a> to the
+given <a title="event">instantaneous event</a> fixes the mapping of this <a title="event">instantaneous event</a> to the
timeline. It can also help with the verification of associated
temporal constraints (though, again, this verification is outside the
-scope of this specfication).
+scope of this specification).
</p>
@@ -953,7 +953,7 @@
<p>
-The assertion of an entity record, <span class="name">entity(id, [ attr1=val1, ...])</span>, states, from a given asserter's viewpoint, the existence of an entity, whose situation in the world is represented by the attribute-value pairs, which remain unchanged during a characterization interval, i.e. a continuous interval between two <a title="event">events</a> in the world.
+The assertion of an entity record, <span class="name">entity(id, [ attr1=val1, ...])</span>, states, from a given asserter's viewpoint, the existence of an entity, whose situation in the world is represented by the attribute-value pairs, which remain unchanged during a characterization interval, i.e. a continuous interval between two <a title="event">instantaneous events</a> in the world.
</p>
<p>
@@ -1031,7 +1031,7 @@
<p>In PROV-DM, an <dfn id="dfn-activity">activity record</dfn> is a representation of an identifiable activity, which performs a piece of work.</p>
-<p>An activity, represented by an activity record, is delimited by its <a title="activity start event">start</a> and its <a title="activity end event">end</a> events; hence, it occurs over an interval delimited by two <a title="event">events</a>. However, an activity record need not mention time information, nor duration, because they may not be known.</p>
+<p>An activity, represented by an activity record, is delimited by its <a title="activity start event">start</a> and its <a title="activity end event">end</a> events; hence, it occurs over an interval delimited by two <a title="event">instantaneous events</a>. However, an activity record need not mention time information, nor duration, because they may not be known.</p>
<p>Such start and end times constitute <em>attributes</em> of an activity, where the interpretation of attribute in the context of an activity record is the same as the interpretation of attribute for entity record: an activity record's attribute remains constant for the duration of the activity it represents. Further characteristics of the activity in the world can be represented by other attribute-value pairs, which MUST also remain unchanged during the activity duration.</p>
@@ -1261,7 +1261,7 @@
<p>A <a title="entity generation event">generation event</a> may be, for example, the completed creation of a file by a program, the completed creation of a linked data set, the completed publication of a new version of a document, and the complete sending of a value on a communication channel. The point at which creation is actually complete is application specific: generation of a file may complete when a lock is released by its creator, whereas actual publication of a document may be after the embargo period that was defined for it.</p>
-<p>A generation record, written <span class="name">wasGeneratedBy(id,e,a,attrs,t)</span> in PROV-ASN, has the following components:</p>
+<p>A generation record, written <span class="name">wasGeneratedBy(id,e,a,t,attrs)</span> in PROV-ASN, has the following components:</p>
<ul>
<li><em>id</em>: an OPTIONAL identifier <span class="name">id</span> identifying the generation record;</li>
<li><em>entity</em>: an identifier <span class="name">e</span> identifying an entity record that represents the entity that is created; </li>
@@ -1343,19 +1343,20 @@
-<p>In PROV-DM, a <dfn id="dfn-Use">usage record</dfn> is a representation of a world <a title="entity usage event">event</a>: the consumption of an entity by an activity. The representation includes a description of the modalities of usage of this entity by this activity.</p>
+<p>In PROV-DM, a <dfn id="dfn-Use">usage record</dfn> is a representation of an instantaneous world <a title="entity usage event">event</a>: an activity beginning to consume an entity. Before this event, the activity had not begun to consume or use to this entity.
+ The representation includes a description of the modalities of usage of this entity by this activity.</p>
<p>
-A <a title="entity usage event">usage event</a> may be the consumption of a parameter by a procedure, the reading of a value on a port by a service, the reading of a configuration file by a program, or the adding of an ingredient, such as eggs, in a baking activity. Usage may entirely consume an entity (e.g. eggs are not longer available after being added to the mix), or leave it as such, ready for further uses (e.g. a file on a file system can be read indefinitely).</p>
-
-
-<p>A usage record, written <span class="name">used(id,a,e,attrs,t)</span> in PROV-ASN, has the following constituent:</p>
+A <a title="entity usage event">usage event</a> may be a procedure beginning to consume a parameter, a service starting to read a value on a port, a program beginning to read a configuration file, or the point at which an ingredient, such as eggs, is being added in a baking activity. Usage may entirely consume an entity (e.g. eggs are not longer available after being added to the mix), or leave it as such, ready for further uses (e.g. a file on a file system can be read indefinitely).</p>
+
+
+<p>A usage record, written <span class="name">used(id,a,e,t,attrs)</span> in PROV-ASN, has the following constituent:</p>
<ul>
<li><em>id</em>: an OPTIONAL identifier <span class="name">id</span> identifying the usage record;</li>
<li><em>activity</em>: an identifier <span class="name">a</span> for an activity record, which represents the consuming activity;</li>
<li><em>entity</em>: an identifier <span class="name">e</span> for an entity record, which represents the entity that is consumed;</li>
<li><em>time</em>: an OPTIONAL "usage time" <span class="name">t</span>, the time at which the entity was used;</li>
-<li><em>attributes</em>: an OPTIONIAL set of attribute-value pairs <span class="name">attrs</span> that describe the modalities of usage of this entity by this activity;</li>
+<li><em>attributes</em>: an OPTIONAL set of attribute-value pairs <span class="name">attrs</span> that describe the modalities of usage of this entity by this activity;</li>
</ul>
<p>In PROV-ASN, a usage record's text matches the <span class='nonterminal'>usageRecord</span> production of the grammar defined in this specification document.</p>
@@ -3412,17 +3413,17 @@
<p>Section <a href="#section-time-event">section-time-event</a>
introduced a notion of <a title="event">instantaneous event</a>
marking changes in the world, in its activities and entities. PROV-DM
-identifies four kinds of events, namely <a>entity generation
+identifies four kinds of <a title="event">instantaneous events</a>, namely <a>entity generation
event</a>, <a>entity usage event</a>, <a>activity start event</a>
and <a>activity end event</a>. PROV-DM adopts Lamport's clock
assumptions [[CLOCK]] in the form of a partial order <a>follows</a>
-(and its inverse <a>precedes</a>) between events. Furthermore,
-PROV-DM assumes the existence of a mapping from events to time clocks,
+(and its inverse <a>precedes</a>) between <a title="event">instantaneous events</a>. Furthermore,
+PROV-DM assumes the existence of a mapping from <a title="event">instantaneous events</a> to time clocks,
though the actual mapping is not in scope of this specification.</p>
<p>Given that provenance records offer a description of past entities
and activities, to be meaningful provenance records MUST
-satisfy <em>event ordering constraints</em>, which we introduce in
+satisfy <em>instantaneous event ordering constraints</em>, which we introduce in
this section. For instance, an entity can only be used after it was
generated; hence, we say that an entity's <a title="entity generation
event">generation event</a> precedes any of this
@@ -3430,15 +3431,15 @@
ordering constraint be proven invalid, the associated generation and
usage records could not be credible. The rest of this section defines
the <dfn>temporal interpretation</dfn> of provenance records as the
-set of event ordering constraints associated with provenance
+set of instantaneous event ordering constraints associated with provenance
records. </p>
<p>PROV-DM also allows for time observations to be inserted in
specific provenance records, for each of the four kinds
-of <a title="event">events</a> introduced in this specification. The
-presence of a time observation for a given <a>event</a> fixes the
-mapping of this <a>event</a> to the timeline. The presence of time
+of <a title="event">instantaneous events</a> introduced in this specification. The
+presence of a time observation for a given <a>instantaneous event</a> fixes the
+mapping of this <a>instantaneous event</a> to the timeline. The presence of time
information in a provenance instantiates the ordering constraint with
that time information. It is expected that such instantiated
constraint can help corroborate provenance information. We anticipate
@@ -3451,14 +3452,14 @@
right. Activities are represented by rectangles, whereas entities are
represented by circles. Usage, generation and derivation records are
represented by the corresponding edges between entities and
-activities. The four kind of events are represented by vertical
+activities. The four kind of <a title="event">instantaneous events</a> are represented by vertical
dotted lines (adjacent to the vertical sides of an activity's
rectangle, or intersecting usage and generation edges). The ordering
constraints are represented by triangles.</p>
<div style="text-align: center;">
<img src="constraints.png" alt="constraints between events" />
-<figcaption id="constraint-summary">Summary of event ordering constraints</figcaption>
+<figcaption id="constraint-summary">Summary of <a title="event">instantaneous event</a> ordering constraints</figcaption>
</div>