Table 1 Non-functional requirements for the platform based on the FURPS+ model

Functionality

Security

Compliant with legislative and regulatory requirements^a

Compliant with enterprise security policies

Extensibility

Capable of integrating new interfaces, data types, connectors, and components

Reusability

System functions should, at minimum, handle structured time-series data. The system should also have sufficient connectors to allow its reuse for new compositions of data and functions

Usability

Aesthetics

Generic and intuitive interfaces providing interpretable data. The various data types should be queried via a single interface. Visualisation interfaces should present data in multiple common formats (trend charts, bar charts, etc.) [11, 42]

Documentation

Well-documented to assist in the reduction of system ambiguity and entropy, and to allow for system extensibility, component replacement, user training, etc

Responsiveness

Limits on stream analysis response times depend on the use case and can range from milliseconds to seconds (alarms and eventing), to daily and weekly reports (process optimization)

Reliability

Accuracy

Intolerant of data and event loss

Availability

Data acquisition, storage systems, and event processing and reporting should have the highest guarantees for availability

Recoverability

Recovery of persisted data (raw and processed) is necessary. Speed of system recovery from faults and the resumption of functions is important

Performance

Throughput

Typically, this is in the order of 10s of Gigabytes (GB) per day

Scalability

The system should scale to accommodate geographically dispersed sources/sinks

Supportability

The components should be well-maintained, stable, active, well-documented, and with a strong, supportive, and responsive user and developer community. They should also be compatible with well-established monitoring solutions