Definitions Constraint blocks provide a mechanism for integrating engineering analysis with other SysML models. Constraint blocks can be used to specify a network of constraints that represent mathematical expressions such as {F=m*a} and {a=dv/dt}, which constrain the physical properties of a system. Such constraints can also be used to identify critical performance parameters and their relationships to other parameters, which can be tracked throughout the system life cycle. (spec) The usage of a constraint binds the parameters of the constraint, such as F, m, and a, to specific properties of a block, such as a mass, that provide values for the parameters. (spec) Pre-and postconditions can be specified that constrain the action such that it cannot begin to execute unless the precondition is satisfied, and must satisfy the postcondition to successfully complete execution. (sandy) In computer programming, a precondition is a condition or predicate that must always be true just prior to the execution of some section of code or before an operation in a formal specification. If a precondition is violated, the effect of the section of code becomes undefined and thus may or may not carry out its intended work. (wiki)

identificationFeasible:Boolean Parametric Mission Domain AirSystem If idFeasibleFunction(avLoc, tarLoc, env) == TRUE, Then idFeas = TRUE idTarget(…) avLoc AirVehicle env position tarLoc idFeas Environment Mission Domain Target identificationFeasible:Boolean position

Activity idTarget <<Precondition>> IdentificationFeasible == TRUE