Presenter: Sue Moon Title: People search, watch, and keep in touch Date: Oct 19, 2007 Time: 12:30-1:15pm Room: BH 4549 Abstract According to Alexa.com, people use the Internet mostly to search, watch, or keep in touch. I will present my research activities framed around these three activities and give a brief overview of my group at KAIST. Then I will delve into the last topic of "keep in touch" and present our WWW 2007 work on huge online soical networking services. I will wrap up the talk with our ongoing work on this topic. Social networking services are a fast-growing business in the Internet. However, it is unknown if online relationships and their growth pattenrs are the same as in real-life social networks. In this paper, we compare the structures of three online social networking services: Cyworld, MySpace, and orkut, each with more than 10 million users, respectively. We have access to complete data of Cyworld's ilchon (friend) relationships and analyze its degree distribution, clustering property, degree correlation, and evolution over time. We also use Cyworld data to evaluate the validity of snowball sampling method, which we use to crawl and obtain partial network topologies of MySpace and orkut. Cyworld, the oldest of the three, demonstrates a changing scaling behavior over time in degree distribution. The latest Cyworld data's degree distribution exhibits a multi-scaling behavior, while those of MySpace and orkut have simple scaling behaviors with different exponents. Very interestingly, each of the two exponents corresponds to the different segments in Cyworld's degree distribution. Certain onlnie social networking services encourage online activities that cannot be easily copied in real life; we show that they deviate from close-knit online social networks which show a similar degree correlation pattern to real-life socal networks. Bio: Sue Moon received her B.S. and M.S. from Seoul National University, Seoul, Korea, in 1988 and 1990, respectively, all in computer engineering. She received a Ph.D. degree in computer science from the University of Massachusetts at Amherst in 2000. From 1999 to 2003, she worked in the IPMON project at Sprint ATL in Burlingame, California. In 2003, she joined KAIST and now works as an Associate Professor. She served as a TPC co-chair for ACM Multimedia 2004 and ACM SIGCOMM MobiArch 2007 and in the program committee for IEEE INFOCOM 2003-2006, World-Wide Web 2007-2008, ACM SIGMETRICS 2005, ACM SIGCOMM Internet Measurement Conference 2007, and many others. Her research interests are: network performance measurement and monitoring of diverse network types and their security, anomaly, and fault resilience aspects. She is currently on sabbatical visiting UCSD until August, 2008.
Presenter: Prof. Hayato Yamana (Waseda University) Title: What's going on in the search engines' ranking? Date: Dec 10, 2007 Time: 1:00pm - 2:30 pm Room: BH 4549 Abstract Most people use search engines daily in order to retrieve documents on the web. Although the social influence of search engines' ranking has become large, ranking algorithms are not disclosed. In this talk, we have investigated three major search engines' rankings by analyzing two kinds of data. One is weekly ranking snapshots of 1000 queries that we gathered for almost one year. And the other is back link data which are generated by our own web crawling. As a result, we have confirmed that (1) their several top tens rankings are similar mutually, (2) their ranking transitions are different each other, and (3) each engine's rankings have their own correlation with the number of back-links. Hayato YAMANA Professor, Department of Computer Science, School of Science and Engineering, Waseda University Born in 1964 in Yamaguchi-pref. JAPAN, Prof. Yamana received his Doctor of Engineering degree at Waseda University in 1993. He began his career at the Electrotechnical Laboratory (ETL) of the former Ministry of International Trade and Industry (MITI), and was seconded to MITI's Machinery and Information Industries Bureau for a year in 1996. He was subsequently appointed Associate Professor of Computer Science at Waseda University in 2000, and has been a professor in that department since 2005. He has written, co-written and translated a number of books including Google Hacks (translation supervisor), Google Pocket Guide (translation), Com Series: An Introduction to Super Parallel Computers (co-author), How to Search the World Wide Web-A Guide to Search Engines (co-author).