The Goal Structuring Notation – New Yellow - The Yellow Book.pptVIP

The Goal Structuring Notation – New Yellow Book Guidance Dr Tim Kelly University of York E-mail: tim.kelly@cs.york.ac.uk What is GSN? Goal Structuring Notation (GSN) - A structured method and notation for developing and presenting (complex) arguments Developed by the University of York(over 15 years ago) Early days – simplified and rationalised notation Core notation has been deliberately kept v. stable Over 1300 safety engineers from over 50 different companies have been educated in GSN Early work involved the development of three Safety Case tools – Safety Argument Manager Now 3+ tools exists that support GSN The Goal Structuring Notation 1 Purpose of a Goal Structure To show how goals are broken down into sub-goals, and eventually supported by evidence (solutions) whilst making clear the strategies adopted, the rationale for the approach (assumptions, justifications) and the context in which goals are stated A Simple Goal Structure A Simple Goal Structure Yellow Book Guidance What is GSN? Introduction to the notation Example Arguments: Argument of compliance with YB fundamentals When to use GSN E.g. When arguments complex or novel How to use GSN E.g. Develop through group discussion Brief overview of the development of a goal structure Links with Safety Planning Possible Pitfalls Turning into Work-Breakdown Structures Fallacy of presentation Yellow Book Guidance - 2 Case Study Examples: New Signalling Scheme Yellow Book Guidance - 3 Other Case Study Examples: New Rolling Stock Application Cross-Acceptance Argument Benefits of GSN Improving planning of safety case arguments Improving comprehension of arguments Improving discussion and reducing time-to-agreement on argument approaches being adopted (Having identified argument structure up front) focusing activities towards the specific end-objectives Easily understood by readers of varying skill levels Supports monitoring of project progress towards a successful safety case