In Japan, the number of single-person households, particularly among the elderly, is increasing. Consequently, opportunities for people to narrate are being reduced. To address this issue, conversational agents, e.g., communication robots and smart speakers, are expected to play the role of the listener. To realize these agents, this paper describes the collection of conversational responses by listeners that demonstrate attentive listening attitudes toward narrative speakers, and a method to annotate existing narrative speech with responsive utterances is proposed. To summarize, 148,962 responsive utterances by 11 listeners were collected in a narrative corpus comprising 13,234 utterance units. The collected responsive utterances were analyzed in terms of response frequency, diversity, coverage, and naturalness. These results demonstrated that diverse and natural responsive utterances were collected by the proposed method in an efficient and comprehensive manner. To demonstrate the practical use of the collected responsive utterances, an experiment was conducted, in which response generation timings were detected in narratives.

Narrating is a fundamental human desire. In order to satisfy the desire, it is more effective to have multiple listeners listen to narratives than to have one listener does. Conversational agents, e.g., communication robots and smart speakers, are expected to listen to narratives, instead of human listeners. For such agents to be recognized as narrative listeners, it is necessary to generate responsive utterances at appropriate timings. This paper proposes a method to estimate the generation timings of responsive utterances by active listeners of spoken narratives. The proposed method estimates them by encoding acoustic and linguistic information extracted from narratives with a transformer-based approach. To evaluate the performance of the proposed method, an experiment was conducted using 131,616 responsive utterances to narratives. The experimental results demonstrated that the proposed method was effective for the estimation and both the acoustic and linguistic information was useful.

Nowadays, spoken dialogue agents such as communication robots and smart speakers listen to narratives of humans. In order for such an agent to be recognized as a listener of narratives and convey the attitude of attentive listening, it is necessary to generate responsive utterances. Moreover, responsive utterances can express empathy to narratives and showing an appropriate degree of empathy to narratives is significant for enhancing speaker’s motivation. The degree of empathy shown by responsive utterances is thought to depend on their type. However, the relation between responsive utterances and degrees of the empathy has not been explored yet. This paper describes the classification of responsive utterances based on the degree of empathy in order to explain that relation. In this research, responsive utterances are classified into five levels based on the effect of utterances and literature on attentive listening. Quantitative evaluations using 37,995 responsive utterances showed the appropriateness of the proposed classification.

This paper proposes a minimally supervised method for acquiring high-level semantic relations such as causality and prevention from the Web. Our method learns linguistic patterns that express causality such as “x gave rise to y”, and uses them to extract causal noun pairs like (global warming, malaria epidemic) from sentences like “global warming gave rise to a new malaria epidemic”. The novelty of our method lies in the use of semantic word classes acquired by large scale clustering for learning class dependent patterns. We demonstrate the effectiveness of this class based approach on three large-scale relation mining tasks from 50 million Japanese Web pages. In two of these tasks we obtained more than 30,000 relation instances with over 80% precision, outperforming a state-of-the-art system by a large margin.

We investigated, via experiment, knowledge of normative honorific expressions as used in textbooks and in practice by people. Forty subjects divided into four groups according to age (younger/older) and gender (male/female) participated in the experiments. The results show that knowledge about the use of normative honorific expressions in textbooks is similar to that demonstrated by the younger subject groups, but differed from that of the older subject groups. The knowledge of the older subjects was more complex than that shown in textbooks or demonstrated by the younger subjects. A model that can identify misuse of honorific expressions in sentences is the framework for this investigation. The model is minimal, but could represent 76% to 92% of the subjects' knowledge regarding each honorific element. This model will be useful in the development of computer-aided systems to help teach how honorific expressions should be used.

BACKGROUND: Automated information extraction from biomedical literature is important because a vast amount of biomedical literature has been published. Recognition of the biomedical named entities is the first step in information extraction. We developed an automated recognition system based on the SVM algorithm and evaluated it in Task 1.A of BioCreAtIvE, a competition for automated gene/protein name recognition. RESULTS: In the work presented here, our recognition system uses the feature set of the word, the part-of-speech (POS), the orthography, the prefix, the suffix, and the preceding class. We call these features "internal resource features", i.e., features that can be found in the training data. Additionally, we consider the features of matching against dictionaries to be external resource features. We investigated and evaluated the effect of these features as well as the effect of tuning the parameters of the SVM algorithm. We found that the dictionary matching features contributed slightly to the improvement in the performance of the f-score. We attribute this to the possibility that the dictionary matching features might overlap with other features in the current multiple feature setting. CONCLUSION: During SVM learning, each feature alone had a marginally positive effect on system performance. This supports the fact that the SVM algorithm is robust on the high dimensionality of the feature vector space and means that feature selection is not required.

In recent years, various types of tagged corpora have been constructed and much research using tagged corpora has been done. However, tagged corpora contain errors, which impedes the progress of research. Therefore, the correction of errors in corpora is an important research issue. In this study we investigate the correction of such errors, which we call corpus correction. Using machine-learning methods, we applied corpus correction to a verb modality corpus for machine translation. We used the maximum-entropy and decision-list methods as machine-learning methods. We compared several kinds of methods for corpus correction in our experiments, and determined which is most effective by using a statistical test. We obtained several noteworthy findings: (1) Precision was almost the same for both detection and correction, so it is more convenient to do both correction and detection, rather than detection only. (2) In general, the maximum-entropy method worked better than the decision-list method; but the two methods had almost the same precision for the top 50 pieces of extracted data when closed data was used. (3) In terms of precision, the use of closed data was better than the use of open data; however, in terms of the total number of extracted errors, the use of open data was better than the use of closed data. Based on our analysis of these results, we developed a good method for corpus correction. We confirmed the effectiveness of our method by carrying out experiments on machine translation. As corpus-based machine translation continues to be developed, the corpus correction we discuss in this article should prove to be increasingly significant.

This paper presents a neural-network-based approach for information retrieval, an important issue in natural language processing. We first describe a method for creating self-organizing documentary maps - visible and continuous representations in which all queries and documents are mapped in topological order according to their similarities. We then show that documents related to queries can be retrieved by merely calculating the Euclidean distances between the positions at which queries and documents are placed and choosing the N closest documents in the ranking order for each query. Small-scale computer experiments have demonstrated that the proposed method is capable of high precision.

The elastic-input neuro-tagger and hybrid tagger, combined with a neural network and Brill's error-driven learning, have already been proposed to construct a practical tagger using as little training data as possible. When a small Thai corpus is used for training, these taggers have tagging accuracies of, respectively, 94.4% and 95.5% (accounting only for the ambiguous words that relate to the parts of speech). In this study, in order to construct more accurate taggers, we developed new tagging methods using three different machine-learning approaches: the decision list, maximum entropy, and the support vector machine methods. We then performed tagging experiments using them. Our results show that the support vector machine method has the best precision (96.1%), and that it is capable of improving the accuracy of tagging in the Thai language. The improvement in accuracy was also confirmed by using a statistical test (a sign test). Finally, we examined theoretically all these methods in an effort to determine how the improvements were achieved. We found that the improvements were due to our use of word information, which is helpful for tagging, and a support vector machine that performed well.

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As a beginning study on self-organizing a general Japanese semantic map, which will be very useful in natural language processing, particularly in document organization and information retrieval, this paper describes the construction of a semantic map of Japanese nouns mapped according to their adnominal constituents. These maps are not only an important part of a general Japanese semantic map that we aim to construct, but can also be a powerful tool for supporting the analysis of the relation between head nouns and their adnominal constituents, an important issue in studies of Japanese pragmatics.

This paper presents a part of speech (POS) neuro tagger which consists of a 3-layer perceptron with elastic input. Computer experiments show that the neuro tagger has an accuracy of 94.4% for tagging ambiguous words when a small Thai corpus with 22,311 ambiguous words is used for training. A series of comparative experiments further show that the neuro tagger is definitely far superior to the statistical models including the frequency model (a base-line model), local n-gram model, and HMM.