## 4 Results
### Logical Architecture  
Figure 2 shows the structure of the AZON platform. The following elements maintained in the same infrastructure appear in the _AZON Subsystems Collaboration_ block:  
* _Depository subsystem_ (digital repository engine),
* _Portal subsystem_ (digital repository front-end),
* _Database subsystem_, _Graph Database Subsystem_, _File Storage Subsystem_ (parts of the AZON platform used for data storage implementation: relational database, graphs database, file system)
* _Local Transcription Subsystem_ (part of the AZON platform responsible for multimedia processing),
* _Image Server Subsystem_, _Datafiles Subsystem_ (web services accountable for content delivering to _Portal Subsystem_ or to be downloaded by the users)
* _Repository Subsystem_, _Sparal Endpoint Subsystem_ (web services used to publish metadata in a semantic form and according to LOD principles)
* _Logon Subsystem_, _API Key Subsystem_ (web services responsible for handling user credentials and assure system security). Logging into the AZON platform and accessing its services works with the SAML mechanism, realized through CAS. The CAS server retrieves authentication data from indicated LDAP and Active Directory servers. For depositors from external universities or institutions with no authentication source (LDAP, AC), registration in the platform is obligatory. The _Logon Subsystem_ is responsible for handling such tasks. However, access for reading is open for everyone with some exceptions enforced by security rules. To reach API offered by AZON components, the users must apply individually for access tokens through _API Key Subsystem_. This subsystem incorporates API Umbrella ([[https://apiumbrella.io](https://apiumbrella.io)]([https://apiumbrella.io](https://apiumbrella.io))) working in the background.
* _Dictionary Editing Subsystem_ (web services used to view and modify dictionaries used in _Depository Subsystem_ or manage custom dictionaries).
* _CSVW Subsystem_ (web service enabling conversion of tabular data in CSV format to RDF format using the CSVW standard ([[https://www.w3.org/TR/tabular-data-model/](https://www.w3.org/TR/tabular-data-model/)]([https://www.w3.org/TR/tabular-data-model/](https://www.w3.org/TR/tabular-data-model/)))). The elements maintained in the external infrastructures (working on an external cloud) appear outside the AZON Subsystems Collaboration block:
* _External Transcription Subsystem_ (service responsible for multimedia processing, like OZONE system used for transcription).  
* _DBC dLibra_ (element used to integrate AZON depository with Lower Silesian Digital Library system).
* _Helpdesk_ (_OTRS_) (element responsible for handling users' help requests and comments).
* _External System_ (any external system that uses AZON API).
* _Digitization Center_ (services running within institutions involved in the project, aimed at resources digitization).  
One may wonder about associations depicted in the diagram or question the subsystems placements. There should be more dependencies among subsystems. Unfortunately, it was not possible to show them all. The diagram only presents an \"architectural outline\" and does not fully reflect it. However, the URLs associated with the main components operating in several locations are real URLs.