Estimating the number of people in rooms and zones within commercial buildings are gaining enormous attention for facilitating various domain applications. However, the deployment of state-of-art counting sensors such as camera technologies can be economically in-viable for individual rooms or zones in large commercial and public buildings. Such sensors are also known to be highly intrusive within building deployments. In this paper, we propose a multi-modal fusion method that leverages the accuracy of camera technologies for estimating building-level counts and the non-intrusive and scalability of wireless fidelity (WiFi) trajectory data to estimate room-level counts. This multi-modal fusion method disaggregates the obtained building-level counts by applying a series of data cleaning methods and a two-step probabilistic method. We evaluate the disaggregation method with datasets from a large teaching building, and we benchmark its performance with a state-of-art estimation algorithm and count estimates from raw WiFi trajectories. The obtained evaluation results highlight that the disaggregation algorithm outperforms other estimation methods by a minimum ratio of 35% for all room cases using the Normalized Root Mean Squared Error (NRMSE) metric.

Sensing accurately the number of occupants in the rooms of a building enables many important applications for smart building operation and energy management. A range of sensor technologies has been studied and applied to the problem. However, it is costly to achieve high accuracy by instrumenting all rooms in a building with dedicated occupant sensors. In this paper, we propose a new concept for estimating accurate room-level counts of occupants. The idea is to disaggregate accurate building-level counts via existing common sensors available at the room level. This solution is cost-effective as it scales to large buildings without requiring dedicated sensors in each room. We propose an algorithm named DCount that implements this concept. Our results document that DCount can provide room-level counts with a low normalized root mean squared error of 0.93. This is a major improvement compared to a state-of-the-art algorithm using common sensors and ventilation rate measurements resulting in a normalized root mean squared error of 1.54 on the same data set. Further more, we demonstrate how the results enable occupant-driven analysis of plug-load consumption which is one out of many applications using accurate room-level counts of occupants we hope to enable by proposing DCount.

In this poster, we present an occupancy count correction method - PreCount that corrects the count errors of camera sensing technologies in real-time. PreCount utilizes supervised machine learning approach to learn error patterns from previous corrections alongside some contextual factors that are responsible for the propagation of these errors. In our evaluation, we compare PreCount with state-of-art methods using the normalized root mean squared error metric (NRMSE) with datasets from four building cases. The obtained evaluation results using ground truth data indicates that PreCount can achieve an error reduction of 68% when compared to raw counts and state-of-art methods.

Cyber-physical systems have enabled the collection of massive amounts of data in an unprecedented level of spatial and temporal granularity. Publishing these data can prosper big data research, which, in turn, helps improve overall system efficiency and resiliency. The main challenge in data publishing is to ensure the usefulness of published data while providing necessary privacy protection. In our previous work (Jia et al. 2017a), we presented a privacy-preserving data publishing framework (referred to as PAD hereinafter), which can guarantee k -anonymity while achieving better data utility than traditional anonymization techniques. PAD learns the information of interest to data users or features from their interactions with the data publishing system and then customizes data publishing processes to the intended use of data. However, our previous work is only applicable to the case where the desired features are linear in the original data record. In this article, we extend PAD to nonlinear features. Our experiments demonstrate that for various data-driven applications, PAD can achieve enhanced utility while remaining highly resilient to privacy threats.