Evaluation of visualization techniques for use by facility operators during monitoring tasks

Facility operators interact with building automation systems (BASs) on a regular basis for various purposes such as facility maintenance, occupant comfort, equipment monitoring, safety and security. Evaluation of various BAS interfaces showed that there are challenges faced by facility operators that impede their efficiency and accuracy of their responses to reported situations. These challenges revolve mainly around the lack of spatial context for the monitored sensor readings and equipment statuses, and operators' information overloading. Various visualization techniques have been used in commercially available BASs, however, their impact on the situation awareness of facility operators is not clearly known. This study focuses on this need and evaluates various visualization techniques that best suit to the needs of facility operators. This study identifies visualization techniques that are applicable to encode sematic information in spatial context, and details the design and implementation of user studies that were performed with seventeen expert and six novice facility operators to understand the impact of visualization techniques on operators' accuracy and timeliness to reported situations in relation to building system monitoring. The findings suggested that visualization-based interfaces generally improve the accuracy and efficiency of facility operators' decisions in monitoring tasks as compared to interfaces designed mainly with tabular displays. The results can be used by practitioners in the industry, not only for greenhouse facility monitoring, but also for facility monitoring in general, and by vendors to consider for their BAS interfaces. (C) 2014 Elsevier B.V. All rights reserved.