|
The
Integrated Hardware/Software Sneak Analysis Approach, written
by Henry Valdez, president of IDA Inc.
This paper will explain the
state of the Integrated Hardware/Software Sneak Analysis technique from
the development of the Baseline Analysis Tools to clue application and
through the completion of the integrated analysis phase. Also, the advantages
of integrating Sneak Analysis with other design and safety analyses will
be discussed, such as an integrated Hardware/ Software Fault Tree Analysis
(FTA), and a Hardware/ Software Failure Modes, Effects and Criticality
Analysis (FMECA).
Sneak
Analysis of Process Control Systems
Boeing developed the Sneak Analysis
technique for the manned space program in 1967 to find unintended modes
of behavior that are not caused by component failure. Since that time,
it has been applied to many types of systems, including military, nuclear,
automotive, mass transit, medical, and petrochemical. Complete systems
including software, hydraulics, pneumatics, as well as electronic hardware,
can be analyzed for sneak conditions. Circuitry can include combinations
of analog and digital technology. Hybrids and application-specific integrated
circuits (ASICs) can be easily accommodated. This paper explains the basic
steps in the Sneak Analysis technique, shows the differences between the
Sneak Analysis approach and other design analysis approaches, and provides
several examples of sneak conditions. Relationships to other design analyses
are discussed and advantages of integrating Sneak Analysis with other
design analyses are shown. Conclusions drawn from actual applications
are presented.
Sneak
Analysis as a Quality Assurance Tool For The Automotive Industry
The development and introduction
of complex, highly integrated electrical/ electronic and microprocessor
based systems into new products poses a major challenge to the automotive
industry. That challenge is to introduce these new technologies while
continually improving the quality of the automotive product. Many of the
tools needed to meet this challenge have been developed in the aerospace
industry and are available to support automotive requirements. Sneak Analysis
is such a tool.
The
Complementry Roles Of Simulation and Sneak Analysis
Sneak Analysis complements simulation
and testing by uncovering problems that may not be otherwise detected.
Sneak Analysis does not predict system behavior for component failures
or specific operational scenarios and, therefore, is not a replacement
for simulation and testing. Simulation can be used to better understand
the impact of conditions uncovered by Sneak Analysis and to evaluate fixes.
Sneak Analysis can reduce schedule risks and costs by detecting errors
before fabrication. Detection of potential operational problems through
Sneak Analysis, including those which might appear as intermittent failures,
can reduce operating costs and improve dispatch reliability. The detailed
topological diagrams produced during Sneak Analysis are also useful for
other analyses, evaluating design changes, and test planning and troubleshooting.
Sneak
Analysis as a Software Reliability Improvement Tool
The development
and introduction of complex, highly integrated electrical/electronic and
microprocessor based systems into new products poses a major challenge
to reliable system operation. Sneak Analysis identifies and corrects reliability-robbing
design conditions, called sneaks, that frequently evade detection by traditional
analysis and testing procedures.
|
|
