Title:	SAFETY-DOMINO: A GRAPHICAL METAPHOR FOR SUPPORTING MINIMAL CUT SETS ANALYSIS
Author(s):	Yasmin I. Al-Zokari, Dirk Zeckzer, Peter Dannenmann, Liliana Guzman, Hans Hagen
ISBN:	978-972-8939-74-8
Editors:	Yingcai Xiao
Year:	2012
Edition:	Single
Keywords:	Safety Visualization, Number Visualization, Basic Events, Minimal Cut Set Order, Minimal Cut Set Failure Probability
Type:	Full Paper
First Page:	63
Last Page:	74
Language:	English
Cover:
Full Contents:	click to dowload
Paper Abstract:	Embedded systems that are safety critical are frequently analyzed to improve their safety, to find out whether the system follows the safety standards. Fault tree analyses enable the safety analysts to find possible causes of a system’s failure or unsafe behavior. From a fault tree, minimal cut sets are computed giving unique combinations of basic events that cause such a failure. Using minimal cut sets, the safety analysts try to find out how to improve the safety of the system with a restricted amount of resources, e.g., cost and time. The two most important results of minimal cut set analyses are the order (number of basic events) and the failure probability of the minimal cut sets. Small order minimal cut sets having 1-3 basic events are the most important ones, because, e.g., a single point of failure is more likely to occur than multiple failures at the same time. However, there is a lack of tools that visualize both failure probability and order of minimal cut sets. Therefore, we designed a graphical metaphor for visualizing the minimal cut set’s order together with its failure probability. The design decisions are based on perception theory. To find the optimal color scheme for the design, we performed an empirical evaluation with 32 participants. The preliminary results of this evaluation show a tendency that the color scheme we call “gray-opposite” performs better than the color scheme we call “black” for larger problem sizes. However, from the participants’ feedback and our observations we concluded that the black color scheme is the best suitable one, because the participants needed to concentrate a lot on the circles with the gray-opposite color scheme. We propose to interpret the results of any evaluation considering the feedback of the participants.
	Go Back