C.28.MR:4.3 - Construct the modified model

Replace each targeted mechanism by its stated constant or function. Retain the other mechanism functions and the supplied input law. Then let their output values follow from the new inputs to those functions.

For a randomized replacement, give its randomization law and its dependence on existing inputs. An independent randomizer is one possible specification. If the proposed change also alters the environment or population, include that change in the compared model instead of silently treating it as part of a constant intervention.

Keep a replacement’s scope visible in time. In a discrete-time model, identify the affected update steps. In an event-driven model, identify the triggering condition and the state change it initiates. A.3.3.TR helps construct the relevant continuation rule from interactions, events and subject laws when that rule is missing.

At the physical interpretation, ask whether the proposed action also changes another modeled mechanism. Changing a supply command and attaching a device that forces its output can have different consequences for current limits and other connections. Add the relevant effects before using the modified model to answer that physical question.