From SweSum to ScandSum- Automatic text summarization for the Scandinavian languages
چکیده
In automatic text summarization, the most relevant parts of a document are extracted and put together in a non-redundant summary that is shorter than the original document. A more advanced form of summarization is multi-text summarization where several texts are condensed into one summary. As the amount of information on the Internet grows abundantly, it is difficult to select relevant information. Automatic text summarization is extremely useful in combination with a search engine on the Web. Automatic text summarization can automatize this work completely or at least assist in the process. In particular, automatic text summarization can be used to prepare information for use in small mobile devices, which may need considerable reduction of content. The techniques used in automatic summarization have interesting spin-off effects in the area of advanced search engine technologies in form of query expansion, such as stemming, the use of thesauri and spell checking of the query. Current Scandinavian summarization tools. SweSum is an automatic text summarizer for Swedish (SweSum 2002) developed at KTH, (see Figure 1). We have currently in this network developed the first version of Danish summarizer. In the commercial area the Norwegian company Cognit AS (Cognit 2002) has a summarizer called Corporum summarizer available for Norwegian, Swedish, German and English. Among the Norwegian language resources that are being reused and, the following are especially mentioned: (a) a word form lexicon with explicit relations between variants in five different subnorms of Bokm l, developed in the European project SCARRIE aimed at spelling and grammar correction in Scandinavian languages, (b) a part of speech tagger developed jointly by the Humanities Information Technology centre at Bergen and Tekstlaboratoriet in Oslo. The summarizer is currently written in Perl. Evaluation Evaluation is an important task in automatic text summarization. Although systems, like summarizers, are currently still dependent on frequency calculations on shallow analyzed texts in order to approximate the relevance of discourse entities, a switch from a stemmer to a lemmatizer will clearly permit to considerably improve their overall performance. Rapid development in mobile communication has enabled the distribution of both textual and multimedia information to various kinds of mobile devices. There are numerous research projects on information services for mobile users as well as (commercial) services (e.g. Plucker or iSilo) that provide offline information for mobile devices. Mobile users may have different information needs depending on their social and environmental contexts as well as their personal interests. Summarization techniques obviously have a key role in this context. Increased pressure for summarization technology advances is coming from mobile users of the web, on-line information sources and new mobile devices, as well as from the need for corporate knowledge management. Commercial companies are increasingly starting to offer text summarization capabilities, often bundled with information retrieval tools. Thus, text summarization for distribution to mobile platforms can be considered a major area of interest within Nordic language technology.