Word sense disambiguation (WSD) is a computational linguistics task likely to benefit from the tradition of combining different knowledge sources in articial intelligence research. An important step in the exploration of this hypothesis is to determine which linguistic knowledge sources are most useful and whether their combination leads to improved results. We present a sense tagger which uses several knowledge sources. Tested accuracy exceeds 94% on our evaluation corpus. Our system attempts to disambiguate all content words in running text rather than limiting itself to treating a restricted vocabulary of words. It is argued that this approach is more likely to assist the creation of practical systems.

The frequent non-availability of an automated oracle means that, in practice, checking software behaviour is frequently a painstakingly manual task. Despite the high cost of human oracle involvement, there has been little research investigating how to make the role easier and less time-consuming. One source of human oracle cost is the inherent unreadability of machine-generated test inputs. In particular, automatically generated string inputs tend to be arbitrary sequences of characters that are awkward to read. This makes test cases hard to comprehend and time-consuming to check. In this paper we present an approach in which a natural language model is incorporated into a search-based input data generation process with the aim of improving the human readability of generated strings. We further present a human study of test inputs generated using the technique on 17 open source Java case studies. For 10 of the case studies, the participants recorded significantly faster times when evaluating inputs produced using the language model, with medium to large effect sizes 60% of the time. In addition, the study found that accuracy of test input evaluation was also significantly improved for 3 of the case studies.

Like text in other domains, biomedical documents contain a range of terms with more than one possible meaning. These ambiguities form a significant obstacle to the automatic processing of biomedical texts. Previous approaches to resolving this problem have made use of various sources of information including linguistic features of the context in which the ambiguous term is used and domain-specific resources, such as UMLS.

Motivation: Word Sense Disambiguation (WSD), automatically identifying the meaning of ambiguous words in context, is an important stage of text processing. This article presents a graph-based approach to WSD in the biomedical domain. The method is unsupervised and does not require any labeled training data. It makes use of knowledge from the Unified Medical Language System (UMLS) Metathesaurus which is represented as a graph. A state-of-the-art algorithm, Personalized PageRank, is used to perform WSD. Results: When evaluated on the NLM-WSD dataset, the algorithm outperforms other methods that rely on the UMLS Metathesaurus alone. Availability: The WSD system is open source licensed and available from http://ixa2.si.ehu.es/ukb/. The UMLS, MetaMap program and NLM-WSD corpus are available from the National Library of Medicine http://www.nlm.nih.gov/research/umls/, http://mmtx.nlm.nih.gov and http://wsd.nlm.nih.gov. Software to convert the NLM-WSD corpus into a format that can be used by our WSD system is available from http://www.dcs.shef.ac.uk/∼marks/biomedical_wsd under open source license. Contact:m.stevenson@dcs.shef.ac.uk