Updated documentation

.docs/index.md

@@ -26,6 +26,5 @@ evolving, allows reproducing of query results and supports findable-, accessible
 ## More Information
 
 - Demonstration instance [https://dbrepo1.ec.tuwien.ac.at](https://dbrepo1.ec.tuwien.ac.at)
-- Test instance [https://test.tuwien.ac.at](https://test.tuwien.ac.at) -- try it yourself!
-- Sandbox instance [https://test.dbrepo.tuwien.ac.at](https://dbrepo2.ec.tuwien.ac.at)
+- Test instance [https://test.dbrepo.tuwien.ac.at](https://test.dbrepo.tuwien.ac.at)
 - System description [https://doi.org/10.2218/ijdc.v17i1.825](https://doi.org/10.2218/ijdc.v17i1.825)

.docs/system-services-search.md

@@ -17,9 +17,59 @@ author: Martin Weise
 
 ## Overview
 
+This service communicates between the [Search Database](../system-databases-search) and 
+the [User Interface](../system-other-ui) to allow structured search of databases, tables, columns, users, identifiers,
+views, semantic concepts & units of measurements used in databases.
 
+## Index
 
-### Examples
+There is only one 
+index [`database`](https://gitlab.phaidra.org/fair-data-austria-db-repository/fda-services/-/raw/dev/dbrepo-search-db/init/indices/database.json)
+that holds all the metadata information which is mirrored from the [Metadata Database](../system-databases-metadata).
+
+<figure markdown>
+![Mirroring statistical properties in Metadata Database and Search Database](images/statistics-mirror.png)
+<figcaption>Statistical properties in Metadata Database and Search Database</figcaption>
+</figure>
+
+## Faceted Browsing
+
+This service enables the frontend to search the `database` index with eight different *types* of desired results 
+(database, table, column, view, identifier, user, concept, unit) and their *facets*.
+
+For example, the [User Interface](../system-other-ui) allows for the search of databases that contain a certain
+semantic concept (provided as URI, e.g. 
+temperature [http://www.wikidata.org/entity/Q11466](http://www.wikidata.org/entity/Q11466)) and unit of measurement 
+(provided as URI, e.g. degree 
+Celsius [http://www.ontology-of-units-of-measure.org/resource/om-2/degreeCelsius](http://www.ontology-of-units-of-measure.org/resource/om-2/degreeCelsius)).
+
+An example on faceted browsing is found in the [usage examples](../usage-search).
+
+## Unit Independent Search
+
+Since the repository automatically collects statistical properties (min, max, mean, median, std.dev) in both the
+[Metadata Database](../system-databases-metadata) and the [Search Database](../system-databases-search), a special
+search can be performed when at least two columns have the same semantic concept (e.g. temperature) annotated and
+the units of measurements can be transformed.
+
+<figure markdown>
+![Two tables with compatible semantic concepts (Temperature) and units of measurement (left is in degree Celsius, right is in degree Fahrenheit)](images/statistics-example.png)
+<figcaption>Two tables with compatible semantic concepts and units of measurement</figcaption>
+</figure>
+
+In short, the search service transforms the statistical properties not in the target unit of measurements is transformed
+by using the [`omlib`](https://github.com/dieudonneWillems/OMLib) package. 
+
+For example: a user wants to find datasets that contain *"temperature measurements between 0 - 10 &deg;C"*. Then the 
+search service transforms the query to the dataset on the right from &deg;F to contain *"temperature measurements
+between 32 - 50 &deg;F"* instead.
+
+<figure markdown>
+![Unit independent search query transformation](images/statistics-example-unit-independent-search.png)
+<figcaption>Unit independent search query transformation</figcaption>
+</figure>
+
+## Examples
 
 See the [usage page](../usage-search).
 
@@ -33,4 +83,4 @@ See the [usage page](../usage-search).
 
 ## Security
 
-TBD
+(nothing)

.docs/usage-metadata.md

----
-author: Martin Weise
----
-
-# Metadata Service
-
-TBD
\ No newline at end of file

.docs/usage-search.md

----
-author: Martin Weise
----
-
-# Search Service
-
-TBD
\ No newline at end of file

mkdocs.yml

@@ -35,8 +35,6 @@ nav:
       - Analyse Service: usage-analyse.md
       - Authentication Service: usage-auth.md
       - Broker Service: usage-broker.md
-      - Metadata Service: usage-metadata.md
-      - Search Service: usage-search.md
       - Storage Service: usage-storage.md
       - Upload Service: usage-upload.md
   - publications.md