Improvement in accuracy of multiple sequence alignment using novel group-to-group sequence alignment algorithm with piecewise linear gap cost(Last author)
Article 1998 ACM:Association for Computing Machinery
Fast speculative search engine on the highly parallel computer EM-X(First author)
高並列コンピュータEM-Xにおける高速投機的検索エンジン
Hayato Yamana, Hanpei Koike, Yuetsu Kodama, Hirofumi Sakane, Yoshinori Yamaguchi SIGIR Forum (ACM Special Interest Group on Information Retrieval)
【抄録】A WWW search engine called fast speculative search engine that uses speculative execution of multiprocessor systems to shorten the total time to retrieve information from the WWW is presented. This engine predicts the user's next queries and initiates the searches with the predicted queries before receiving them to accelerate narrowing the search space. This fast speculative search engine is implemented using the data speculation on the EM-X, a highly parallel computer which can tolerate communication latency by using low latency communication and multithreading.
Article 1998 ACM:Association for Computing Machinery
Experiments of collecting WWW information using distributed WWW robots(First author)
分散型WWWロボットを用いたWWW情報収集の実験
Hayato Yamana, Kent Tamura, Hiroyuki Kawano, Satoshi Kamei, Masanori Harada, Hideki Nishimura, Isao Asai, Hiroyuki Kusumoto, Yoichi Shinoda, Yoichi Muraoka SIGIR Forum (ACM Special Interest Group on Information Retrieval)
【抄録】This paper presents the experiments of collecting the documents on the WWW using distributed WWW robots. We propose distributed WWW robots to collect the documents quickly. Our final goal is to collect all of the documents on the WWW in Japan within one day. Currently, eight distributed WWW Robots are running in Japan. The experimental results show that we are able to gain 5.8 to 9.7 times speedup when four distributed WWW robots are placed at different places in comparison with when only one WWW robot is used.
Article 1996 電子情報通信学会:The Institute of Electronics, Information and Communication
Message-based efficient remote memory access on a highly parallel computer EM-X
高並列コンピュータEM-Xにおけるメッセージベースの効率的なリモートメモリアクセス
Yuetsu Kodama, Hirohumi Sakane, N. Mitsuhisa Sato, Hayato Yamana, Shuichi Sakal, Yoshinori Yamaguchl IEICE Transactions on Information and Systems
【抄録】Communication latency is central to multiprocessor design. This study presents the design principles of the EM-X distributed-memory multiprocessor towards tolerating communication latency. The EM-X overlaps computation with communication for latency tolerance by multithreading. In particular, we present two types of hardware support for remote memory access: (1) priority-based packet scheduling for thread invocation, and (2) direct remote memory access. The prioritybased scheduling policy extends a FIFO ordered thread invocation policy to adopt to different computational needs. The direct remote memory access is designed to overlap remote memory operations with thread execution. The 80-processor prototype of EM-X is developed and is operational since December 1995. We execute several programs on the machine and evaluate how the EM-X effectively overlaps computation with communication toward tolerating communication latency for high performance parallel computing.