Preface to the special issues on NTCIR-4

The ACM TALIP Special Issues on NTCIR-4 contain fourteen papers selected from the papers submitted by researchers involved in the Fourth NTCIR Workshop (NTCIR-4). The NTCIR Workshops are a series of evaluation workshops designed to enhance research in information access technologies such as information retrieval (IR), question answering, summarization, text mining, and so on, by providing large-scale evaluation infrastructures and a forum for researchers interested in cross-system comparisons and in exchanging research ideas in an informal atmosphere. Because fundamental text processing, such as indexing, includes language-dependent procedures, the NTCIR project began in late 1997, and has placed emphasis on East Asian languages such as Japanese, Chinese, Korean, (and English documents published in Asia), and its series of workshops has attracted international participation. An NTCIR workshop is held about once every one and a half years. Because we respect all the interactions among the participants, we consider the entire process from initial document release to the final meeting as the workshop. Each workshop selects several research areas, called “tasks,” or “challenges” for the more challenging tasks. A task may consist of more than one subtask. From the beginning of the project, the tasks were selected with a focus along two directions: (a) laboratory-type testing of IR systems, and (b) evaluating challenging technologies. For testing IR systems, we placed emphasis on East Asian languages and on testing various document genres. For the challenging issues, we looked at the technologies that utilize “information” in documents; the intersection of IR and natural language processing; and at the methodologies and metrics that provide more realistic and reliable evaluations, with special attention to users’ information-seeking tasks. The NTCIR-4 focused on five tasks: Cross-Lingual Information Retrieval (CLIR); Patent Retrieval (PATENT); Question Answering (QAC); Text Summarization (TSC);