Welcome to the Takizawa laboratory!

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Introduction to Takizawa laboratory

The Takizawa laboratory belongs to the Dept. of Advanced Sciences, Faculty of Science and Engineering, Hosei University
With the supervise of Prof. Makoto Takizawa, we are studying & researching on distributed systems: especialy communication networks & databases.

Communication Networks

High speed networks with the capacity of Giga-bps class, using optical fibers, are going to be in general until the year 2010. In those days, distributed applications, such as tele-conference, tele-medicine, tele-classroom and so on, would be in used. Distributed applications need to make entities create groups and act cooperatively.
Communication protocols used by these days, like OSI, TCP/IP, etc., are for high relativity and efficiency in communication between two entities. In comparison with this, entities in a group needs to communicate with each other, that opponents may be two or more. You can say that a communication of "line", and this of "plane" and call this a group communication. In group communication, messages send from each entities has to be delivered to plural entities in the group. Then, the message must be recieved only when all of the entities in the group can recieve it, and not in any when even a single entity can't. Say this a atomic recievment. Also, when number of entity is communicating messages, the order of the message recieved in the group would be a problem. For some instance of ordering, there are total ordering, all entities would recieve messages in the same order, and local order preserving, preserving only the order of the sending.


In these days, computer systems work cooperatively by connecting each other by communication networks. We call those kind of systems a distributed system. When many people use a distributed system at the same time, it would be difficult to keep the data-base's integrity and the through put in level. Also, there would be impossible to utilize existing databases as an unified application.

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