Published Papers - YOSHIHIRO Takuya

Avoiding Routing Loops on the Internet

Hiro Ito, Kazuo Iwama, Yasuo Okabe, Takuya Yoshihiro

Theory of Computing Systems   36 ( 6 ) 597 - 609   2003.11  [Refereed]

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Suppose that some particular link in the Internet is currently congested. A natural solution is to try to make packets bypass that link. This can be done by increasing the cost of that link intentionally, say from a1 to a2, since the Internet uses shortest-path routing. Unfortunately, however, this often causes temporary loops for packet traveling, called routing loops. In this paper we show that routing loops can be avoided by increasing the cost of the link not directly from a1 to a2 but through an intermediate value, a3, i.e., from a1 to a 3 and then to a2. We may need several intermediate values. We show that in this case the greedy strategy, namely, raising the cost as much as possible in each step, is optimal.

DOI

Polynomial-Time Computable Backup Tables for Shortest-Path Routing

Hiro Ito, Kazuo Iwama, Yasuo Okabe, Takuya Yoshihiro （Part： Lead author,　Corresponding author )

Carleton Scientific Proc. SIROCC 2003     163 - 177   2003

Avoiding Routing Loops on the Internet

Hiro Ito, Kazuo Iwama, Yasuo Okabe, Takuya Yoshihiro （Part： Lead author,　Corresponding author )

Carleton Scientific Proc. of SIROCCO 2002     197 - 210   2002

Stateless Autoconfiguration of IPv6 Site-Local Addresses.

Takuya YOSHIHIRO, Masayuki SHIMADA, Yasuo OKABE, Kazuo IWAMA

IASTED Proc. of CCN 2002     299 - 304   2002

A Method for Searching Recorded Lectures in Distance Education

KATAYAMA Kaoru, KAGAWA Osami, KAMIYA Yasuhiro, TSUSHIMA Hideki, YOSHIHIRO Takuya, KAMBAYASHI Yahiko

Transactions of Information Processing Society of Japan ( 一般社団法人情報処理学会 )  39 ( 10 ) 2837 - 2845   1998.10

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Support of searching recorded lectures is important in distance education systems because students review parts of lectures they need and teachers reuse their past lectures easily. We view lecturing as a process of making multimedia teaching materials. It is difficult to search multimedia data in general. Although automatic scene analysis and speech recognition are very popular among researchers, it si still not easy to form reliable index. Our approach is different from these ways of searching multimedia data directly. We use information which are connected to continuous media such as video and audio with synchronous constraints during lectures, that is, texts contained in slides, sequences of events of pens and pointers (called Action History) and so on. In conventional systems search of lectures is supported only in a unit of slides or annotations. Our system provides a flexible search mechanism by combining search functions for various recorded information, for example, string search for texts, a search function for action histories, fast forward and rewind of video and so on. User interfaces are also provided to enable users to search lectures for idle talk or search them in a unit of blocks which are semantic units of slides.