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Humans like to express their opinions and are eager to know others’ opinions. Automatically mining and organizing opinions from heterogeneous information sources are very useful for individuals, organizations and even governments. Opinion extraction, opinion summarization and opinion tracking are three important techniques for understanding opinions.(More)
This paper describes an overview of the Multilingual Opinion Analysis Task from 2007 to 2008 at the Seventh NTCIR Workshop. We created test collections of 22, 17, 17, 16 topics (7,163, 4,711, 6,174, and 5,301 sentences) in Japanese, English, Traditional Chinese, and Simplified Chinese. Using this test collection, we conducted five subtasks: (1) mandatory(More)
This paper describes an overview of the Opinion Analysis Pilot Task from 2006 to 2007 at the Sixth NTCIR Workshop. We created test collection for 32, 30, and 28 topics (11,907, 15,279, and 8,379 sentences) in Chinese, Japanese and English. Using this test collection, we conducted opinion extraction subtask. The subtask was defined from four perspectives:(More)
Question answering systems provide an elegant way for people to access an underlying knowledge base. Humans are not only interested in factual questions but also interested in opinions. This paper deals with question analysis and answer passage retrieval in opinion QA systems. For question analysis, six opinion question types are defined. A two-layered(More)
Opinion retrieval aims to tell if a document is positive, neutral or negative on a given topic. Opinion extraction further identifies the document’s supportive and the non-supportive evidence. This paper defines the annotation of opinionated material. The algorithm employs opinion holders, a topic’s conceptual words, sentiment words, opinion operators, and(More)
In recent years, major natural disasters have made it more challenging for us to protect human lives. Examples include the 2011 Japan Tohoku earthquake and Typhoon Morakot in 2009 in Taiwan. However, modern disaster warning systems cannot automatically respond efficiently and effectively to disasters. As a result, it is necessary to develop an automatic(More)
This paper employs morphological structures and relations between sentence segments for opinion analysis on words and sentences. Chinese words are classified into eight morphological types by two proposed classifiers, CRF classifier and SVM classifier. Experiments show that the injection of morphological information improves the performance of the word(More)