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COmments on OBOE and QB
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Simon Cox committed Jun 11, 2018
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Expand Up @@ -199,12 +199,12 @@ <h3>Ultimate feature of interest</h3>
The relationship of the ultimate feature of interest to observations and acts of sampling is illustrated in the figures below.</p>

<figure id="fig-observation-ultimate-foi">
<img alt="Observation feature-of-interest patterns" src="./images/observation-foi-patterns.png"/>
<img alt="Observation feature-of-interest patterns" src="./images/observation-foi-patterns.png" width="75%"/>
<figcaption>Patterns for observations that relate to the ultimate feature of interest directly (top), or indirectly via one sample (middle) or a chain of samples (bottom)</figcaption>
</figure>

<figure id="fig-sampling-ultimate-foi">
<img alt="Sampling feature-of-interest patterns" src="./images/sampling-foi-patterns.png"/>
<img alt="Sampling feature-of-interest patterns" src="./images/sampling-foi-patterns.png" width="75%"/>
<figcaption>Patterns for sampling that relate to the ultimate feature of interest directly (top), or indirectly via one intermediate sample (middle) or a chain of intermediate samples (bottom)</figcaption>
</figure>

Expand All @@ -220,16 +220,32 @@ <h3>Homogeneous collection of observations</h3>

<p>
A collection of observations may share a common value for one or more of the characteristic observation properties.
For example, an <code>oboe:Observation</code> is a collection of <code>oboe:Measurements</code> concerning a common <code>oboe:Entity</code>, with each <code>oboe:Measurement</code> reporting the value of a different <code>oboe:Characteristic</code>.
A <a href="https://www.w3.org/TR/vocab-ssn/#OBOE_Alignment">alignment module in SSN</a> [[vocab-ssn]] provided an alignment for the atomic <code>oboe:Measurement</code> to <a href="https://www.w3.org/TR/vocab-ssn/#SOSAObservation">sosa:Observation</a>, but not for <code>oboe:Observation</code>.
Another example is that many monitoring processes generate a stream of data in which only the (phenomenon-) time changes between consecutive results.
Another case is where a sensor network generates a set of results at the same time for a suite of features-of-interest.
For example:
</p>
<ul>
<li>
an <code>oboe:Observation</code> is a collection of <code>oboe:Measurements</code> concerning a common <code>oboe:Entity</code>, with each <code>oboe:Measurement</code> reporting the value of a different <code>oboe:Characteristic</code>.
An <a href="https://www.w3.org/TR/vocab-ssn/#OBOE_Alignment">alignment module in SSN</a> [[vocab-ssn]] provided an alignment for the atomic <code>oboe:Measurement</code> to <a href="https://www.w3.org/TR/vocab-ssn/#SOSAObservation">sosa:Observation</a>, but not for <code>oboe:Observation</code>.
</li>
<li>
many monitoring processes generate a stream of data in which only the (phenomenon-) time changes between consecutive results for the same property on a single feature of interest.
</li>
<li>
a sensor network typically generates a set of results, at the same time, for the same property(s) of a suite of features-of-interest.
</li>
</ul>
</p>
<p>
This pattern can be accommodated by introducing a new class <code>ObservationCollection</code> which may hold one or more of the properties <a href="https://www.w3.org/TR/vocab-ssn/#SOSAhasFeatureOfInterest">hasFeatureOfInterest</a>, <a href="https://www.w3.org/TR/vocab-ssn/#SOSAobservedProperty">observedProperty</a>, <a href="https://www.w3.org/TR/vocab-ssn/#SOSAobservedProperty">madeBySensor</a>, <a href="https://www.w3.org/TR/vocab-ssn/#SOSAusedProcedure">usedProcedure</a>, <a href="https://www.w3.org/TR/vocab-ssn/#SOSAphenomenonTime">phenomenonTime</a>, or <a href="https://www.w3.org/TR/vocab-ssn/#SOSAresultTime">resultTime</a>.
These patterns can be accommodated by introducing a new class <code>ObservationCollection</code> which may hold one or more of the properties <a href="https://www.w3.org/TR/vocab-ssn/#SOSAhasFeatureOfInterest">hasFeatureOfInterest</a>, <a href="https://www.w3.org/TR/vocab-ssn/#SOSAobservedProperty">observedProperty</a>, <a href="https://www.w3.org/TR/vocab-ssn/#SOSAobservedProperty">madeBySensor</a>, <a href="https://www.w3.org/TR/vocab-ssn/#SOSAusedProcedure">usedProcedure</a>, <a href="https://www.w3.org/TR/vocab-ssn/#SOSAphenomenonTime">phenomenonTime</a>, or <a href="https://www.w3.org/TR/vocab-ssn/#SOSAresultTime">resultTime</a>.
Where present, the value of the property(s) of the collection are shared by all member observations.
Only the value of each actual <a href="https://www.w3.org/TR/vocab-ssn/#SOSAhasResult">hasResult</a> is not potentially shared by all member observations.
</p>

<figure id="observation-collection">
<img alt="Collection of observations sharing one or more key properties" src="./images/observation-collection.png" width="75%"/>
<figcaption>Model for an observation-collection, in which the collection may carry one or more of the properties of its members if they have a shared value for all members</figcaption>
</figure>

<p>
Collections may be nested.
For example, an outer observation-collection may share an observed-property, procedure and sensor, and contain inner observation-collections at different phenomenon-times, each containing a set of observations on different features-of-interest.
Expand All @@ -239,16 +255,19 @@ <h3>Homogeneous collection of observations</h3>
A formal alignment of SSN and this extension to the W3C Datacube vocabulary [[vocab-data-cube]] is provided below.
</p>


<figure id="observation-collection">
<img alt="Collection of observations sharing one or more key properties" src="./images/observation-collection.png"/>
<figcaption>Model for an observation-collection, in which the collection may carry one or more of the properties of its members if they have a shared value for all members</figcaption>
</figure>

<p>
Note that this requirement was addressed in OM-Lite [[OM-Lite]] following the pattern described here.
</p>

<figure id="oboe-implementation">
<img alt="The OBOE core model" src="./images/OBOE-core.png"/ width="40%"><img alt="The SSN-ext model arranged to align with OBOE" src="./images/SOSA-ssn-ext.png" width="50%"/>
<figcaption>
The OBOE core model (left), shown alongside the SSN-ext model (right) with comparable classes and properties aligned.
</figcaption></figcaption>
</figure>



</section>

</section>
Expand Down Expand Up @@ -502,7 +521,7 @@ <h4 id="container-property-rule">Inheriting observation properties from a collec
The rules may be defined formally as SPARQL query expressions [[!sparql11-query]] as follows:
</p>
<p class="note">
Update rules to chase up a chain of observation collections.
Update rules to chase up a chain of observation collections.
</p>
<table class="definition" style="width: 812px;">
<thead>
Expand Down Expand Up @@ -648,9 +667,12 @@ <h2>Examples</h2>
<section>
<h2>Alignments</h2>
<section>
<h3>W3C Data Cube vocabulary</h3>
<h3>RDF Data Cube vocabulary</h3>
<p>
TBD
The W3C RDF Data Cube vocabulary [[vocab-data-cube]] provides a means to describe multi-dimensional data according to a 'data cube' model inspired by SDMX. The RDF Data Cube vocabulary uses the term <i>observation</i> for the <b>results</b>, and the <i>dimensions</i> of a data cube indicate the <b>features of interest</b> and <b>phenomenon times</b> of the results, the <i>measures</i> correspond to the <b>observed properties</b>, and the <i>attributes</i> accommodate information about the <b>procedures</b> and <b>sensors</b>.
</p>
<p>
A <i>slice</i> selects a subset of the 'observations' by fixing a subset of the dimensions, and thus delivers the set of <b>results</b> of <b>observation-collections</b> with fixed <b>features-of-interest</b> or <b>phenomenon-times</b> or both.
</p>
</section>
<section>
Expand Down

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