Page 21 - U4SSC Compendium of survey results on integrated digital solutions for city platforms around the world

2 Logstash: a data-processing channel on the server side that ingests data from multiple sources
simultaneously, transforms them and sends them to Elasticsearch.
3 Kibana: allows users to view data stored in Elasticsearch using tables and graphs.

This log monitoring tool is, in turn, integrated with a powerful event monitoring tool (OSSEC).

The database engines used are:

• Time series database (InfluxDB).
• Relational database (MySQL).

• NoSQL database (MongoDB).
• Distributed file system (HDFS).

• Open data management system (CKAN).

The platform has Big Data based on two frameworks, Apache HUE and Apache HIVE, a Hadoop
tool. They offer an SQL-like or SQL-based query language.

The platform allows the exchange of data with other consumer entities – as occurs, for example,
with information from volcanological stations, whose data are sent to the systems of entities in
charge of analysing and exploiting their data.

In order to send data, the tool must have an API HTTP that can receive the data sent from the
platform through the Context Broker.

Likewise, an open-data portal has also been developed, in which the information available on the
platform about the different components is uploaded.

The IoT agents are in charge of receiving data from the devices/sensors and adapting them from
the capture protocols to the consumption format by the Orion Context Broker. IoT agents, due to
their southbound interface, are in charge of communicating directly with the different sensorization
devices and performance, and by its north interface (northbound) with the API NGSI9 and NGSI10
through the Orion Context Broker. This modular architecture enables the implementation of
different IoT agents that respond to a totally heterogeneous range of devices that use different
communication protocols and transfer the information to a common language at the platform level
based on standardized NGSI entities.

Each IoT agent provides the ability to interact with devices with a specific protocol. If a specific
modelling – or “mapping” of attributes – is desired, it is necessary to provide the rules to apply,
which may require the provision of the devices to establish a specific model associated with a

Compendium of survey results on integrated digital solutions for city platforms around the world 9