eventtriggered

Event-triggered, or event-triggered, refers to a design principle where actions are initiated in response to events rather than on a fixed schedule. This contrasts with time-triggered systems that execute tasks at predetermined times regardless of external conditions. In event-triggered approaches, components monitor signals, messages, or state changes and execute the corresponding handlers, updates, or control actions when a defined event is detected. The concept is widely applied across engineering, software, and data processing, with terminology such as interrupts, listeners, triggers, or messages.

In control and robotics, event-triggered control reduces unnecessary communication and computation by sending updates only when an error or threshold is exceeded. This can save bandwidth and energy while preserving stability, but design must avoid excessive triggering and Zeno behavior, where events occur infinitely often in finite time. Common approaches rely on Lyapunov functions, error bounds, or polling strategies to determine triggering conditions.

In software engineering and user interfaces, event-driven programming uses an event loop and handlers that respond to user actions or asynchronous signals. Frameworks such as JavaScript and Node.js exemplify this model. In data architectures, triggers enforce rules on data changes, while event-driven architectures use messaging systems (pub/sub or queues) to decouple producers and consumers and react to streams of events.

Benefits include responsiveness, scalability, and resource efficiency, while challenges include debugging complexity, nondeterministic execution order, and potential latency from queues.