@inproceedings{WiegandKlakow2012,
  author    = {Wiegand, Michael and Klakow, Dietrich},
  title     = {Generalization Methods for In-Domain and Cross-Domain Opinion Holder Extraction},
  series = {Proceedings of the 13th Conference of the European Chapter of the Association for Computational Linguistics, April 23-27 2012, Avignon France},
  publisher = {Association for Computational Linguistics},
  address   = {Stroudsburg, PA},
  isbn      = {978-1-937284-19-0},
  url       = {http://nbn-resolving.de/urn:nbn:de:bsz:mh39-84378},
  pages     = {325 -- 335},
  year      = {2012},
  abstract  = {In this paper, we compare three different generalization methods for in-domain and cross-domain opinion holder extraction being simple unsupervised word clustering, an induction method inspired by distant supervision and the usage of lexical resources. The generalization methods are incorporated into diverse classifiers. We show that generalization causes significant improvements and that the impact of improvement depends on the type of classifier and on how much training and test data differ from each other. We also address the less common case of opinion holders being realized in patient position and suggest approaches including a novel (linguistically-informed) extraction method how to detect those opinion holders without labeled training data as standard datasets contain too few instances of this type.},
  language  = {en}
}
@inproceedings{WiegandKlakow2011,
  author    = {Wiegand, Michael and Klakow, Dietrich},
  title     = {The Role of Predicates in Opinion Holder Extraction},
  series = {Proceedings of the RANLP 2011 Workshop on Information Extraction and Knowledge Acquisition,16 September, 2011, Hissar, Bulgaria},
  publisher = {Incoma Ltd.},
  address   = {Shoumen},
  isbn      = {978-954-452-018-2},
  url       = {http://nbn-resolving.de/urn:nbn:de:bsz:mh39-84564},
  pages     = {13 -- 20},
  year      = {2011},
  abstract  = {In this paper, we investigate the role of predicates in opinion holder extraction. We will examine the shape of these predicates, investigate what relationship they bear towards opinion holders, determine what resources are potentially useful for acquiring them, and point out limitations of an opinion holder extraction system based on these predicates. For this study, we will carry out an evaluation on a corpus annotated with opinion holders. Our insights are, in particular, important for situations in which no labelled training data are available and only rule-based methods can be applied.},
  language  = {en}
}