【日時】東京大学 理学部7号館214教室 （辻井研）
# 夜には会食も予定しております

【話者】Ms. Ruihua Song
【題目】Identification of ambiguous queries in web search
【概要】It is widely believed that many queries submitted to search engines
are inherently ambiguous(e.g., java and apple). However, few studies
have tried to classify queries based on ambiguity and to answer "what
the proportion of ambiguous queries is." Our work deals with these
issues. First, we clarify the definition of ambiguous queries by
constructing the taxonomy of queries from being ambiguous to
specific. Second, we ask human annotators to manually classify
queries. From manually labeled results, we observe that query
ambiguity is to some extent predictable. Third, we propose a
supervised learning approach to automatically identify ambiguous
queries. Experimental results show that we can correctly identify 87%
of labeled queries with the approach. Finally, by using our approach,
we estimate that about 16% of queries in a real search log are
ambiguous.

Bio: Ms. Ruihua Song received B.E. and M.E. degrees from Tsinghua
University in 2000 and 2003. Then she joined Microsoft Research Asia
and now works as a researcher in Web Data Management group. Her main
research interests are Web information retrieval and Web information
extraction. She serves SIGIR, SIGKDD, CIKM, ECIR, etc. as PC members
and NTCIR as a coordinator. Her homepage is
http://research.microsoft.com/users/rsong/.

【話者】Tetsuya Sakai
【題目】Different Intents, Different Views - New Evaluation Methods
【概要】This talk consists of two parts.  First, I will describe a new
method for evaluating diversified Web search results that are output
in response to ambiguous or underspecified queries.  I will show some
experimenal results with the TREC 2009 Web track data and demostrate
the advantages of my approach over existing methods.  Second, I will
describe a new method for evaluating the task of finding good answers
from community question answering (CQA) data.  Handling user-generated
contents such as CQA data is particularly challenging because they
vary widely in quality and reflect different people's subjective
views.  I will show some latest results from the NTCIR-8 CQA task to
demonstrate the advantages of my approach.

Bio: Tetsuya Sakai received a Master's degree from Waseda University
in 1993 and joined the Toshiba Corporate R&D Center in the same
year. He received a Ph.D from Waseda University in 2000 for his work
on information retrieval and filtering systems.  From 2000 to 2001, he
was a visiting researcher at the University of Cambridge Computer
Laboratory. In 2007, he became the Director of the Natural Language
Processing Laboratory at NewsWatch, Inc. In 2009, he joined Microsoft
Research Asia. He is the ACM SIGIR Regional Representative to the
Executive Committee (Asia/Pacific) and Chair of IPSJ SIG-IFAT.  He has
served as a Senior PC member for ACM SIGIR and for CIKM. He is on the
editorial board of Informaiton Processing and Management and that of
Information Retrieval the Journal.  He has received several awards in
Japan, mostly from IPSJ.