온톨로지 구축 및 단어 의미 중의성 해소에의 활용

To save time, healthcare providers frequently use abbreviations while authoring clinical documents. Nevertheless, abbreviations that authors deem unambiguous often confuse other readers, including clinicians, patients, and natural language processing (NLP) systems. Most current clinical NLP systems "post-process" notes long after clinicians enter them into electronic health record systems (EHRs). Such post-processing cannot guarantee 100% accuracy in abbreviation identification and disambiguation, since multiple alternative interpretations exist. Authors describe a prototype system for real-time Clinical Abbreviation Recognition and Disambiguation (rCARD) - i.e., a system that interacts with authors during note generation to verify correct abbreviation senses. The rCARD system design anticipates future integration with web-based clinical documentation systems to improve quality of healthcare records. When clinicians enter documents, rCARD will automatically recognize each abbreviation. For abbreviations with multiple possible senses, rCARD will show a ranked list of possible meanings with the best predicted sense at the top. The prototype application embodies three word sense disambiguation (WSD) methods to predict the correct senses of abbreviations. We then conducted three experments to evaluate rCARD, including 1) a performance evaluation of different WSD methods; 2) a time evaluation of real-time WSD methods; and 3) a user study of typing clinical sentences with abbreviations using rCARD. Using 4,721 sentences containing 25 commonly observed, highly ambiguous clinical abbreviations, our evaluation showed that the best profile-based method implemented in rCARD achieved a reasonable WSD accuracy of 88.8% (comparable to SVM - 89.5%) and the cost of time for the different WSD methods are also acceptable (ranging from 0.630 to 1.649 milliseconds within the same network). The preliminary user study also showed that the extra time costs by rCARD were about 5% of total document entry time and users did not feel a significant delay when using rCARD for clinical document entry. The study indicates that it is feasible to integrate a real-time, NLP-enabled abbreviation recognition and disambiguation module with clinical documentation systems.

This paper presents a method of word sense disambiguation that assigns a target word the sense that is most related to the senses of its neighbor words. We explore the use of measures of relatedness between word senses based on a novel hybrid approach. First, we investigate how to literally and regularly express a concept. We apply set algebra to Wordnet’s synsets cooperating with Wordnet’s word ontology. In this way we establish regular rules for constructing various representations (lexical notations) of a using Boolean operators and various word forms in synset(s). Then we construct a formal mechanism for quantifying and estimating the semantic relatedness between concepts - we facilitate concept distribution statistics to determine the degree of semantic relatedness between two lexically expressed concepts. Then we applied the measure of semantic relatedness to the WSD task. The experimental results showed good performance on Semcor, a subset of Brown corpus. We observe that measures of semantic relatedness are useful sources of information for word sense disambiguation.

This paper describes EPROP, a novel technique requiring little prior knowledge for word sense disambiguation of semantic relations between pairs of ambiguous concepts in knowledge bases. Our method makes inferences by aggregating evidences from ambiguous word interpretations and propagating the acquired knowledge over a taxonomy to generalize or specialize this knowledge. This propagation process allows the estimation of the degree of belief for each possible word sense assignment given the available evidence. EPROP only requires a sense inventory structured as a taxonomy to disambiguate a knowledge base by combining evidence from the ambiguous facts stored in the knowledge base. We have performed different experiments that show that our method achieves good results on the disambiguation of the semantic relations included in WordNet and ConceptNet. We also show how our method can be used to improve the performance of state-of-the-art word sense disambiguation methods.

For most Web searching applications, queries are commonly ambiguous because words usually contain several meanings. Traditional Word Sense Disambiguation (WSD) methods use statistic models or ontology-based knowledge models to find the most appropriate sense for the ambiguous word. Since queries are usually short, the contexts of the queries may not always provide enough information for disambiguating queries. Thus, more than one interpretation may be found for one ambiguous query. In this paper, we propose a cluster-based WSD method, which finds out all appropriate interpretations for the query. Because some senses of one ambiguous word usually have very close semantic relations, we group those similar senses together for explaining the ambiguous word in one interpretation. If the cluster-based WSD method generates several contradictory interpretations for one ambiguous query, we extract users’ preferences from clickthrough data, and determine suitable concepts or concepts’ clusters that meet users’ interests for explaining the ambiguous query.

For most Web searching applications, queries are commonly ambiguous because words usually contain several meanings. Traditional Word Sense Disambiguation (WSD) methods use statistic models or ontology-based knowledge models to find the most appropriate sense for the ambiguous word. Since queries are usually short, the contexts of the queries may not always provide enough information for disambiguating queries. Thus, more than one interpretation may be found for one ambiguous query. In this paper, we propose a cluster-based WSD method, which finds out all appropriate interpretations for the query. Because some senses of one ambiguous word usually have very close semantic relations, we group those similar senses together for explaining the ambiguous word in one interpretation. If the cluster-based WSD method generates several contradictory interpretations for one ambiguous query, we extract users’ preferences from clickthrough data, and determine suitable concepts or concepts’ clusters that meet users’ interests for explaining the ambiguous query.

This paper presents a method of word sense disambiguation that assigns a target word the sense that is most related to the senses of its neighbor words. We explore the use of measures of relatedness between word senses based on a novel hybrid approach. First, we investigate how to “literally” and “regularly” express a “concept”. We apply set algebra to Wordnet's synsets cooperating with Wordnet's word ontology. In this way we establish regular rules for constructing various representations (lexical notations) of a concept using Boolean operators and word forms in various synset(s) defined in Wordnet. Then we establish a formal mechanism for quantifying and estimating the semantic relatedness between concepts – we facilitate “concept distribution statistics” to determine the degree of semantic relatedness between two lexically expressed concepts. Human languages have words that can mean different things in different contexts, such words with multiple meanings are potentially “ambiguous”. The process of “deciding which of several meanings of a term is intended in a given context” is known as “Word Sense Disambiguation (WSD)”. The proposed method is not supervised, and does not require any manually created sense‐tagged training examples. The experimental results showed good performance on Semcor, a subset of the Brown corpus. We observe that measures of semantic relatedness are useful sources of information for word sense disambiguation.

Query expansion is a classical topic in the field of information retrieval, which is proposed to bridge the gap between searchers' information intents and their queries. Previous researches usually expand queries based on document collections, or some external resources such as WordNet and Wikipedia [1, 2, 3, 4, 5]. However, it seems that independently using one of these resources has some defects, document collections lack semantic information of words, while WordNet and Wikipedia may not include domain-specific knowledge in certain document collection. Our work aims to combine these two kinds of resources to establish an expansion model which represents not only domain-specific information but also semantic information. In our preliminary experiments, we construct a two-layer word graph and use Random-Walk algorithm to calculate the weights of each term in pseudo-relevance feedback documents, then select the highest weighted term to expand original query. The first layer of the word graph contains terms in related documents, while the second layer contains semantic senses corresponding to these terms. These terms and semantic senses are treated as vertices of the graph and connected with each other by all possible relationships, such as mutual information and semantic similarities. We utilized mutual information, semantic similarity and uniform distribution as the weight of term-term relation, sense-sense relation and word-sense relation respectively. Though these experiments show that our expansion outperform original queries, we are troubled with some difficult problems. Given the framework of semantic graph model, we need more effort to find out an optimal graph to represent the relationships between terms and their semantic senses. We utilized a two-layer graph model in our preliminary research, where terms from different documents are treated equally. Maybe we can introduce the document as a third layer in future work, where we can differ the same terms in different documents according to document relevance and context. Then we need appropriately represent initial weights of this words, senses and relationships. Various measures for weights of terms and term relations have been proved effective in other information retrieval tasks, such as TFIDF, mutual information (MI), but there is little research on weights for semantic senses and their relations. For polysemous words, we add all of their semantic senses to the graph and assume that these senses are uniformly distributed. Actually, it is not precise for a word in a special document and query. As we know, a polysemous word may have only one or two senses in a document, and they are not uniformly distributed. Give a word, what we should do is to determine its word senses in a relevant document and estimate the distribution of these senses. Word sense disambiguation may help us in this problem. Then, there are many methods to compute word similarity according to WordNet, which we use to represent the weights of relationships between word senses. Varelas et al implemented some popular methods to compute semantic similarity by mapping terms to an ontology and examining their relationships in that ontology [4]. We also need to know which algorithm for semantic similarity is most suitable for our model. Additional, WordNet is suitable to calculate word similarity but not suitable to measure word relevance. The inner hyperlinks of Wikipedia could help us to calculate word relevance. We wish to find an effective way to combine the similarity measure from WordNet and relevance measure from Wikipedia, which may completely reflect word relationships.

We present RedunWSD, a Word Sense Disambiguation (WSD) based redundancy removal method for multiple text documents query-based text summarization. Recognizing and identifying the redundancy from the text documents is a challenging task that has not been fully resolved yet. In the case of multiple text document summarization processes, redundancy removal helps in getting maximum content coverage by minimizing any redundant or repetitive sentences. Another novel contribution of our work is the disambiguating a word's sense, since it helps us in getting accurate semantic similarity score between two sentences. Along with the semantic similarity score, we also consider the order of words between two sentences. Our model has the additional advantage of detecting the redundant sentences based on its meaning. Our experimental results show that the proposed WSD method outperforms many existing and current WSD methods. We have evaluated the proposed RedunWSD method on Document Understanding Conference (DUC) benchmark datasets and show that it helps in getting better recall values than many top existing query-based text summarization methods.

BackgroundIn recent years, deep learning methods have been applied to many natural language processing tasks to achieve state-of-the-art performance. However, in the biomedical domain, they have not out-performed supervised word sense disambiguation (WSD) methods based on support vector machines or random forests, possibly due to inherent similarities of medical word senses.ResultsIn this paper, we propose two deep-learning-based models for supervised WSD: a model based on bi-directional long short-term memory (BiLSTM) network, and an attention model based on self-attention architecture. Our result shows that the BiLSTM neural network model with a suitable upper layer structure performs even better than the existing state-of-the-art models on the MSH WSD dataset, while our attention model was 3 or 4 times faster than our BiLSTM model with good accuracy. In addition, we trained “universal” models in order to disambiguate all ambiguous words together. That is, we concatenate the embedding of the target ambiguous word to the max-pooled vector in the universal models, acting as a “hint”. The result shows that our universal BiLSTM neural network model yielded about 90 percent accuracy.ConclusionDeep contextual models based on sequential information processing methods are able to capture the relative contextual information from pre-trained input word embeddings, in order to provide state-of-the-art results for supervised biomedical WSD tasks.

Word sense disambiguation (WSD) has always being a key problem and one of difficult points in natural language processing. WSD is usually considered to be a pattern classification to be research. Feature selection is an important sector of WSD process. We review naive Bayes model (NBM) seriously, and the feature selection method adopted in this paper is directed at Bayesian Assumption to improve NBM. Positional information concealed in the context of ambiguous word is mined via information gain calculation, to increase the knowledge acquisition efficiency of Bayesian model and to improve the effect of word-sense classification. Eight ambiguous words are tested in our experiment; the experimental results of improved Bayesian model are higher 3.5 per cent than the ones of NBM. The accuracy rise is bigger and the improvement effect is outstanding; and these results prove also the method put forward in this paper is efficacious.

Objectives: To identify ontology concepts from text documents for the construction of work process ontology. Methods: This study proposes a methodology to identify terms representing a work process ontology concept from a document. The methodology encompasses several key steps: document collecting, text pre-processing, term weighting and analysis, terms mapping, and domain expert relevance judgments. A comparison between the results of three different term weighting schemes, namely the Term Frequency (TF), Term Frequency-Inverse Document Frequency (TFIDF), and Mutual Information (MI) is made with the ontology concept that the domain expert has judged. Findings: The approaches adopted in this study have managed to extract ontological concepts from the targeted domain knowledge source. The findings of the comparison analysis suggest that the TFIDF term weighting scheme exhibits better results compared to the TF and MI weighting schemes. Novelty: A work process ontology is a structured knowledge describing daily operations in the government sector. However, there has been little to no effort in building the work process ontology. This study presents an integrated approach for identifying ontology concepts from documents within the domain of the work process. To the utmost extent of our understanding, this research initiative is the initial attempt to introduce a structured methodology for the semi-automatic extraction and evaluation of concepts and relationships within this domain. The findings can be utilised as a foundation for developing an ontology in the specific field. Keywords: Ontology, Work process, Text extraction, Natural language processing, Term weighting

India is widely renowned for having many different languages. Indians must be quite proud of the rich diversity of languages in their country. As there are numerous languages and a large number of meaningful words. There are terms that have synonyms in every language. There will be a time when learning a new language is necessary. Natural language processing (NLP) is helpful in achieving such. It has been around for more than 50 years, and the roots of NLP may be found in the study of language. It is used in a variety of fields, including corporate intelligence, search engines, and medical research. Ambiguity is the quality of being subject to multiple interpretations, and is frequently referred to as the imprecision of a word's meaning. The method for fixing this problem is called disambiguation. This study used a large- scale dataset that included words with many meanings and senses. Additionally, the dataset is in Telugu, the regional language of Andhra Pradesh. Some of the Telugu words in this dataset are unclear when used in various contexts. Deep neural networks are utilized to do this. Two algorithms namely Bidirectional Long Short Term Memory (BiLSTM) and Bidirectional Gated Recurrent Unit (RBGRU) are used in order to obtain the noticeable sense of given ambiguous word. Accurate word sense prediction achieved an accuracy of 86.30% for word sense disambiguation for regional language results. This outcome is remarkable when compared with other approaches of word sense prediction of various regional languages

A Chinese word sense disambiguation algorithm based on HowNet is proposed in this paper. After extracting the ambiguous words in the text, the correlative words which restrict the word sense in the context can be found by using dependency grammar analysis. Finally, by computing the semantic relevancy between the atomic term of ambiguous words and the correlative words, the correct meaning of the ambiguous word can be determined by the value of the semantic relevancy. Experimental results show that the method has a good effect on Chinese word sense disambiguation.

Word Sense Disambiguation (WSD) is the task of extracting an appropriate sense of an ambiguous word in a sentence. WSD is an essential task for language processing, as it is a pre-requisite for determining the closest interpretations of various language-based applications. In this paper, we have made an attempt to exploit the word embedding for finding the solution for WSD for the Hindi texts. This task involves two steps - the creation of word embedding and leveraging cosine similarity to identify an appropriate sense of the word. In this process, we have considered two mostly used word2vec architectures known as Skip-Gram and Continuous Bag-Of-Words [2] models to develop the word embedding. Further, we have chosen the sense with the closest proximity to identify the meaning of an ambiguous word. To prove the effectiveness of the proposed model, we have performed experiments on large corpora and have achieved an accuracy of nearly 52%.

Natural language processing (NLP) tasks such as word sense disambiguation, machine translation (MT) and part-of-speech tagging etc. require large scale lexical resources. These lexical resources have already been developed for digitally advanced languages, such as English, but yet to be developed for widely spoken but digitally young languages, such as Punjabi. WordNet is one such lexical resource that can be used for variety of NLP tasks ranging from digital dictionary to automated MT. The basic building block of WordNet is synset, a word sense with which one or more synonymous words are associated. Each synset in WordNet is linked to other synsets using lexical and semantic relations. Lexical relations are between word forms, whereas semantic relations exist between two whole synsets. This paper presents lexical and semantic relations of Punjabi WordNet, including synonymy, hypernymy/hyponymy, meronymy/holonomy, entailment and troponymy etc. It also illustrates the process of creation of Punjabi synsets from Hindi synsets, design of synsets and semantic databases for implementation of semantic relations for Punjabi WordNet.