CAST a database: Rapid targeted large-scale big data acquisition via small-world modelling of social media platforms

The adage that there is no data like more data is not new in affective computing; however, with recent advances in deep learning technologies, such as end-to-end learning, the need for extracting big data is greater than ever. Multimedia resources available on social media represent a wealth of data more than large enough to satisfy this need. However, an often prohibitive amount of effort has been required to source and label such instances. As a solution, we introduce Cost-efficient Audio-visual Acquisition via Social-media Small-world Targeting (CAS
²
T) for efficient large-scale big data collection from online social media platforms. Our system is based on a unique combination of small-world modelling, unsupervised audio analysis, and semi-supervised active learning. Such an approach facilitates rapid training on entirely new tasks sourced in their entirety from social multimedia. We demonstrate the high capability of our methodology via collection of original datasets containing a range of naturalistic, in-the-wild examples of human behaviours.