Does Visualization Speed Up the Safety Analysis Process?

Abstract

The goal of this paper is to present our experience in utilizing the power of the information visualization (InfoVis) field to accelerate the safety analysis process of Component Fault Trees (CFT) in embedded systems. For this, we designed and implemented an interactive visual tool called ESSAVis, which takes the CFT model as input and then calculates the required safety information (e.g., the information on minimal cut sets and their probabilities) that is needed to measure the safety criticality of the underlying system. ESSAVis uses this information to visualize the CFT model and allows users to interact with the produced visualization in order to extract the relevant information in a visual form. We compared ESSAVis with ESSaRel, a tool that models the CFT and represents the analysis results in textual form. We conducted a controlled user evaluation study where we invited 25 participants from different backgrounds, including 6 safety experts, to perform a set of tasks to analyze the safety aspects of a given system in both tools. We compared the results in terms of accuracy, efficiency, and level of user acceptance. The results of our study show a high acceptance ratio and higher accuracy with better performance for ESSAVis compared to the text-based tool ESSaRel. Based on the study results, we conclude that visual-based tools really help in analyzing the CFT model more accurately and efficiently. Moreover, the study opens the door to thoughts about how the power of visualization can be utilized in such domains to accelerate the safety assurance process in embedded systems.