It is essential for public acceptance that the mass transit computer systems (i.e., software), electrical systems, and the systems they control be operationally safe and reliable. "Sneak Analysis" assures system operability by identifying all potential anomalies which can be caused by unplanned operational modes inherent in the system design. The correction or avoidance of these modes will then lead to a safer, more reliable system. Boeing Aerospace Company has found that "network trees" containing combinations of four basic topological patterns constitute all electrical systems and their analogs. Utilizing these topological trees, all latent signal paths which can inadvertently initiate a function or inhibit a desired one--independent of component failure--are detected. Sneak Analysis has found latent operational capabilities in every system analyzed, including parts of the San Francisco Bay Area Rapid Transit and Morgantown Personal Rapid Transit systems. The technique also aids in locating areas of weak design. The resulting network trees can aid in shortening test and troubleshooting time. These also simplify the work required and accuracy of other analysis techniques which specifically examine component, environmental, and human related operational problems. The ability of the analysis technique to disclose unsafe operational modes after other techniques have certified reliability and even after years of normal operation indicates that Sneak Analysis is almost essential in critical areas of transportation systems.

Media Info

  • Features: Figures; References;
  • Pagination: p. 715-730

Subject/Index Terms

Filing Info

  • Accession Number: 00180344
  • Record Type: Publication
  • Source Agency: System Safety Society
  • Report/Paper Numbers: Proceeding
  • Files: TRIS
  • Created Date: Sep 27 1981 12:00AM