Tatsumi Yoshida

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Recently, we can acquire immence amount of information thanks to the spread of a computer and inter-net. Therefore, technology for finding the information that a user desires becomes more and more important. A question answering (QA) system answers a question written by natural language in contrast to conventional information retrieval systems where a user(More)
In this paper, we consider a ramp scheme for Key Predistribution System (KPS). In the ramp scheme, it can be regarded as one kind of generalization of KPS, and the required resources can be reduced at the cost of a security degradation which depends on the size of users. We define a ramp scheme for KPS, show lower bound on the amount of user' s information(More)
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