text: Extracting location names from informal and unstructured social media data requires the identification of referent boundaries and partitioning compound names. Variability, particularly systematic variability in location names (Carroll, 1983), challenges the identification task. Some of this variability can be anticipated as operations within a statistical language model, in this case drawn from gazetteers such as OpenStreetMap (OSM), Geonames, and DBpedia. This permits evaluation of an observed n-gram in Twitter targeted text as a legitimate location name variant from the same location-context. Using n-gram statistics and location-related dictionaries, our Location Name Extraction tool (LNEx) handles abbreviations and automatically filters and augments the location names in gazetteers (handling name contractions and auxiliary contents) to help detect the boundaries of multi-word location names and thereby delimit them in texts. We evaluated our approach on 4,500 event-specific tweets from three targeted streams to compare the performance of LNEx against that of ten state-of-the-art taggers that rely on standard semantic, syntactic and or orthographic features. LNEx improved the average F-Score by 33-179 , outperforming all taggers. Further, LNEx is capable of stream processing.
  @cite_26: We consider the problem of resolving duplicates in a database of places, where a place is defined as any entity that has a name and a physical location. When other auxiliary attributes like phone and full address are not available, deduplication based solely on names and approximate location becomes an exceptionally challenging problem that requires both domain knowledge as well an local geographical knowledge. For example, the pairs "Newpark Mall Gap Outlet" and "Newpark Mall Sears Outlet" have a high string similarity, but determining that they are different requires the domain knowledge that they represent two different store names in the same mall. Similarly, in most parts of the world, a local business called "Central Park Cafe" might simply be referred to by "Central Park", except in New York, where the keyword "Cafe" in the name becomes important to differentiate it from the famous park in the city. In this paper, we present a language model that can encapsulate both domain knowledge as well as local geographical knowledge. We also present unsupervised techniques that can learn such a model from a database of places. Finally, we present deduplication techniques based on such a model, and we demonstrate, using real datasets, that our techniques are much more effective than simple TF-IDF based models in resolving duplicates. Our techniques are used in production at Facebook for deduplicating the Places database.
summary: : use beam search and structured perceptron for extraction and linking to Foursquare entities. However, they did not address the noise that is prevalent in such sources (e.g., my sofa'' or our house'') @cite_26 .