Usability Assessment of the Visualization-Driven Approaches to the HVAC Data Exploration

Application of the Internet-connected operational devices in the heating, ventilation and conditioning (HVAC) systems has extended the cyber-attack surface by introducing different malicious scenarios. The analysis of the HVAC data may provide insight on typical patterns of the system operations. Implementation of the thoroughly elaborated visualization models may significantly increase the efficiency of the suspicious activity identification in the HVAC systems. In the paper we present the results of the laboratory usability testing of three visualization models used to analyze HVAC data – matrix-based visualization technique, non-linear multidimensional visualization technique RadViz and timeline chart. Matrix-based visualization and RadViz visualization are often used in anomaly detection process, while timeline charts are a traditional way to present operational HVAC data. We describe the experiment design and discuss the results obtained. The usability testing revealed advantages and limitations of these visualization techniques in behavior pattern and anomaly identification tasks. The results can further serve as guidelines for task-dependent selection of a visualization technique.