Learning On-the-Job to Re-rank Anomalies from Top-1 Feedback
Hemank Lamba, Leman Akoglu · Society for Industrial and Applied Mathematics eBooks · 2019
In many anomaly mining scenarios, a human expert verifies the anomaly at-the-top (as ranked by an anomaly detector) before they move on to the next. This verification produces a label—true positive (TP) or false positive (FP). In this work, we show how to leverage this label feedback for the top-1 instance to quickly re-rank the anomalies in an online fashion. In contrast to a detector that ranks once and goes offline, we propose a detector called OJRank that works alongside the human and continues to learn (how to rank) on-the-job, i.e., from every feedback. The benefits OJRank provides are two-fold; it reduces (i) the false positive rate by ‘muting’ the anomalies similar to FP instances; as well as (ii) the expert effort by elevating to the top the anomalies similar to a TP instance. We show that OJRank achieves statistically significant improvement on both detection precision and human effort over the offline detector as well as existing state-of-the-art ranking strategies, while keeping the per feedback response time (to re-rank) well below a second.