Thanks to the large availability of portable devices and the growing interest in the Internet of Things, during crises, social networks, or alerts sent through mobile devices or sensor networks are available and can be matched each other to perform situational analysis. However, the inclusion of multiple heterogeneous sources in situational analyses leads to 2 main issues: (1) a source could deliver (voluntarily or erroneously) wrong data damaging the integrity and the correctness of the analysis, and (2) a significant amount of heterogeneous data need to be processed. As a consequence, the crisis management operator faces a large amount of potentially unreliable data.In this paper, we present a relevance labelling strategy to process information gathered from heterogeneous data streams to select the most relevant events. These are presented to the crisis management operator with the highest priority. Our strategy is evaluated using events collected by the Secure! crisis management system, considering 3 real crisis scenarios happened in Italy in 2015. Results show that our strategy is able to correctly identify sets of relevant events, supporting the activities of the crisis management operator. Recently, the interest in researching and developing CMSs is growing significantly, mainly due to an increasing number of available information. 3,4 This includes information provided by physical sensors and humans, both citizens and trained personnel, which generate information (eg, using their smartphones 5,6 ) accessible through social networks. 7,8 On one side, having multiple information sources is a benefit for the analysis of a crisis scenario, but on the other side, the risk is that the crisis management operator is overloaded of potentially unreliable information, negatively affecting the response process. For this reason, the information needs to be processed and filtered to become readable and trusted for the human operator.Crisis data from the citizens generate Volunteered Geographic Information (VGI 6 ) that is shared for example through SMS, 9 Social Media, 10 or dedicated applications. 11 This activity involves crowd-sourcing 12 and crowd-sensing 13 techniques: crowd-sourcing is the process of obtaining needed services, ideas, or content by soliciting contributions from a crowd of people (eg, online communities), while crowd-sensing refers to the involvement of a large group of participants in retrieving reliable data from a specific field. Considering "human sensors"
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