(c) Bruce Powel Douglass, Ph.D. 2019

Safety Analysis and Design

What is Safety?

Safety is freedom from accidents or losses.

  • Normally concerned with human or animal death or injury

  • May be applied to any system in which you desire to avoid certain outcomes

 

Safety is not reliability!

  • Reliability is the probability that a system will perform its intended function satisfactorily.

  • Reliability is a stochastic measure system function delivery

 

Safety is not security!

  • Security is protection or defense against attack, interference, or espionage.

  • Note: the German word sicherheit relates to both security and safety, but we draw a distinction in English

 

Dependability is the term used for the integration of Safety, Reliability, and Security

 

Resilience is the term for the ability of a system to provide service under different, often unexpected, circumstances. It includes Dependability and Adaptability.

Example Fault Tree Analysis
with the UML Dependability Profile (see bottom of page)

Some Safety Presentations

Safety Critical 1:

Analysis Practices

Safety Critical 2:

Design Practices

Safety Critical 3:

Quality Practices

Safety Critical 4:

Evidence-oriented Practices

The UML Dependability Profile

This Rhapsody profile supports safety, reliability, and security analysis.