130,453 research outputs found

    Finding Eyewitness Tweets During Crises

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    Disaster response agencies have started to incorporate social media as a source of fast-breaking information to understand the needs of people affected by the many crises that occur around the world. These agencies look for tweets from within the region affected by the crisis to get the latest updates of the status of the affected region. However only 1% of all tweets are geotagged with explicit location information. First responders lose valuable information because they cannot assess the origin of many of the tweets they collect. In this work we seek to identify non-geotagged tweets that originate from within the crisis region. Towards this, we address three questions: (1) is there a difference between the language of tweets originating within a crisis region and tweets originating outside the region, (2) what are the linguistic patterns that can be used to differentiate within-region and outside-region tweets, and (3) for non-geotagged tweets, can we automatically identify those originating within the crisis region in real-time

    Contextual queries express mobile information needs

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    The users of mobile devices increasingly use networked services to address their information needs. Questions asked by mobile users are strongly influenced by contextual factors such as location, conversation and activity. We report on a diary study performed to better understand mobile information needs. We find that the type of questions recorded by participants varies across their locations, with differences between home, shopping and in-car contexts. These variations occur both in the query terms and in the form of desired answers. Both the location of queries and the participants' activities affected participants' questions. When information needs were affected by both location and activity, they tended to be strongly affected by both factors. The overall picture that emerges is one of multiple contextual influences interacting to shape mobile information needs. Mobile devices that attempt to adapt to users' context will need to account for a rich variety of situational factors

    Unnamed locations, underspecified regions, and other linguistic phenomena in geographic annotation of water-based locations

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    This short paper investigates how locations in or close to water masses in topics and documents (e.g. rivers, seas, oceans) are referred to. For this study, 13 topics from the GeoCLEF topics 2005-2008 aiming at documents on rivers, oceans, or sea names were selected and the corresponding relevant documents retrieved and manually annotated. Results of the geographic annotation indicate that i) topics aiming at locations close to water contain a wide variety of spatial relations (indicated by dierent prepositions), ii) unnamed locations can be generated on-the-fly by referring to movable objects (e.g. ships, planes) travelling along a path, iii) underspecied regions are referenced by proximity or distance or directional relations. In addition, several generic expressions (e.g. "in international waters") are frequently used, but refer to different underspecified regions
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