A concrete component architecture for integrating small Internet of Things (IoT) devices into larger business processes is central in this easy-to-follow and comprehensive paper. Against the backdrop of an ambient assisted living system supporting people in constant need of medical supervision (for example, temperature, blood pressure, heart rate), the authors develop and performance test a sound and novel architecture for distributed process execution.
The architecture uses several common and tried integration patterns--message brokers for asynchronous, event-based communications; proxies for decoupling logical from physical service providers; service registries; manager applications for performing certain special tasks, like replacing failed IoT devices; and separation of rules execution from process enactment--all within the paradigm of RESTful services.
Key differentiating aspects of the proposal are (1) a set-top box (STB) not only for executing the processes, but also for power-efficient communication with local (IoT) sensor devices; (2) execution of monitoring processes directly on a smartphone (plus Bluetooth communications with wearable sensors) for a use case where patients leave their stationary home with fixed sensors; and (3) a programming framework for allowing business users to develop process applications. The last claim has not been validated, though.
A first set of performance tests is quite revealing. For instance, the use of IoT-optimized communication protocols (like the constrained application protocol) instead of hypertext transfer protocol (HTTP) between sensors and an STB is mandatory to achieve latencies below 500 ms. Additionally, the introduction of a message broker merely adds 12 ms latency, and the use of software proxies for replacing failed sensors is 20 times faster than re-instantiation with a new sensor (80 ms versus 1,600 ms).
Summing up: this is a must-read for every architect and process specialist working in the domain where distributed process execution and IoT aspects meet.
