Social media signal processing

In the last decade, social networks emerged as a new information dissemination medium that propagates information regarding the physical world. Written from the perspective of an embedded systems engineer, this chapter draws an analogy between physical sensing modalities, such as acoustic sensing, magnetic sensing, and seismic sensing on the one hand, and the emerging social sensing modality on the other. Much in the way physical targets cause signal propagation through a physical medium, world events cause information propagation on the social medium. Understanding the properties of such propagation allows one to reconstruct the events that caused it in the first place. We call such reconstruction social sensing. The chapter models information dissemination on social media as an engineering problem, drawing on solutions inspired by modeling signal propagation on physical media. It describes simple signal processing techniques for the social sensing modality and reviews experiences using social sensing for event detection, demultiplexing, and veracity analysis, demonstrating advantages and limitations of the engineering approach.