Extracting Resource Needs and Availabilities From Microblogs for Aiding Post-Disaster Relief Operations

Microblogging sites like Twitter are the important sources of real-time information during disaster/emergency events. During such events, the critical situational information posted is immersed in a lot of conversational content; hence, reliable methodologies are needed for extracting the meaningful information. In this paper, we focus on a particular application that is critical for efficient management of post-disaster relief operations - identifying tweets that inform about resource needs and resource availabilities. Two broad types of methodologies can be practically applied to identify such tweets during an ongoing disaster event: 1) supervised classification approaches, where the classifier models are trained on microblogs posted during prior events and applied on those posted during the ongoing event and 2) unsupervised pattern matching and information retrieval approaches that can be directly applied on the microblogs posted during the ongoing event. In this paper, we experiment with several supervised and unsupervised approaches to address the problem, including several neural network-based classification and retrieval models. We also propose two novel neural retrieval models (unsupervised) for the said application, which effectively combine word-level embeddings and character-level embeddings. We conduct experiments on tweets posted during two disaster events and observe that the two approaches perform well in different scenarios. Specifically, if good quality training data are available from prior events, then classification approaches perform better; however, if such training data are not available, then unsupervised retrieval methods outperform supervised classification approaches.