Software Ha zard Anal Level 3 Specification(modeling)language goals · Readable and reviewable Minimize semantic distance Minimal(blackbox) Easy to learn Unambiguous and simple semantics Complete Can specify everything need to specify Analyzable Executable Formal(mathematical) foundation ludes human actions Assists in finding incompleteness Software Hazard Analysis SpecTRM-RL Combined requirements specification and modeling language a state machine with a more readable notation on top of it Includes a task modeling language Could add other notations and visualizations of state machine Enforces or includes most of completeness criteria Supports specifying systems in terms of modes Control modes Operational modes Supervisory modes Display modes
✡☎✣✞✡☎✆✞✙☎✕✔✥✧✦✩★☎✲ ✂✙☎✚✠✛✜✍☎✑✡✔☞✜✍☎✏✞✍☎✑✒✔✓✂✕☎✍☎✗✝✞✆✞✘✆ c ✢ Level 3 Specification (modeling) language goals Readable and reviewable Minimize semantic distance Minimal (blackbox) Easy to learn Unambiguous and simple semantics Complete Can specify everything need to specify Analyzable Executable Formal (mathematical) foundation Includes human actions Assists in finding incompleteness c ✢✡☎✣✞✡☎✆✞✙☎✕✔✥✧✦✩✰☎✳ ✂✙☎✚✠✛✜✍☎✑✡✔☞✜✍☎✏✞✍☎✑✒✔✓✂✕☎✍☎✗✝✞✆✞✘✆ SpecTRM−RL Combined requirements specification and modeling language A state machine with a more readable notation on top of it Includes a task modeling language Could add other notations and visualizations of state machine Enforces or includes most of completeness criteria Supports specifying systems in terms of modes Control modes Operational modes Supervisory modes Display modes
Software Hazard Ana lysis Model of process Process is modeled using state variables Traffic Density Schedule Slot [1...90] LoW Available Average Aircraft scheduled High Blocked Unknown Unknow Values of state variables given by AND/OR tables Software Environment Sensor Measured variable 1 Measured Variable 2 Component SUPERVISORY: INFERRED SYSTEM OPERATING MODES Control CONTROL INFERRED SYSTEM STATE Command Controlled Supervisor MODES Device
c ✢✡☎✣✞✡☎✆✞✙☎✕✔✥✧✦✩✰✪✦ ✂✙☎✚✠✛✜✍☎✑✡✔☞✜✍☎✏✞✍☎✑✒✔✓✂✕☎✍☎✗✝✞✆✞✘✆ Model of Process Process is modeled using state variables Average Low Unknown High Traffic Density Schedule Slot [1...90] Unknown Blocked Aircraft Scheduled Available Values of state variables given by AND/OR tables c ✢✡☎✣✞✡☎✆✞✙☎✕✔✥✧✦✩✰☎✫ ✂✙☎✚✠✛✜✍☎✑✡✔☞✜✍☎✏✞✍☎✑✒✔✓✂✕☎✍☎✗✝✞✆✞✘✆ Component MODE SUPERVISORY CONTROL INFERRED SYSTEM OPERATING MODES MODES Measured Variable Command Control Display Output Control Input Controlled Device Measured Variable 1 Measured Variable 2 Supervisor (Feedback) Sensor Environment INFERRED SYSTEM STATE
Digital altitude Altimeterstatus altitude Altimeterstatus Analog altitude Altimeterstatus Altitude Device of interest InterfaceA Inhibit Signal Switch Power-on Signal (DOI) Reset Signal DOI Status Signal Strobe Watchdog Timer
Altimeter Digital Altimeter Analog Digital Altimeter Pilot Interface Device of Interest Switch (DOI) Altitude Watchdog Timer Power-on Signal Strobe DOI Status Signal altitude status altitude status altitude status Inhibit Signal Reset Signal