Blackbox specifications Provide a blackbox statement of software behavior Permits statements only in terms of outputs and externally observable conditions or events that stimulate or trigger those outputs trigger output(double implication) Complete trigger specification must include full set of conditions that may be inferred from existence of specified output Such conditions represent the assumptions about the environment in which program or system is to operate Thus the specification is the input to output function computed by the component, i.e., the transfer function Internal design decisions are not included Softwa Process models Define required blackbox behavior of software in terms of a state machine model of the process(plant) Measured SensorsLvariables Process inputs Human Automated Controller Controlled Model of Disturbances Process Process Model of Model of Displays Process Automation Actuators Process Controlled variablesc ✢✡☎✣✞✡☎✆✟✙☎✕✔✥✯✦✩★☎✰ ￾✖✙✤✚✠✛✜✍☎✑✡✔☞✎✍☎✏✞✍☎✑✒✔✓✖✕☎✍☎✗✝✞✆✞✘✆ Blackbox specifications Provide a blackbox statement of software behavior: Permits statements only in terms of outputs and externally observable conditions or events that stimulate or trigger those outputs. trigger output (double implication) Complete trigger specification must include full set of conditions that may be inferred from existence of specified output. Such conditions represent the assumptions about the environment in which program or system is to operate. Thus the specification is the input to output function computed by the component, i.e., the transfer function. Internal design decisions are not included. ✡☎✣✞✡☎✆✟✙☎✕✔✥✯✦✩★☎✱ ￾✖✙✤✚✠✛✜✍☎✑✡✔☞✎✍☎✏✞✍☎✑✒✔✓✖✕☎✍☎✗✝✞✆✞✘✆ Process Models Define required blackbox behavior of software in terms of a state machine model of the process (plant). c ✢ Sensors variables Controls Displays Model of Process Actuators Controlled Measured Disturbances Process Model of Automated Process inputs outputs Process Human Automation Model of Controller Process Controlled Supervisor variables