Masaya Nakayama

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1 Introduction In this paper we propose a new hash-partitioned join method using a dynamic de&aging strategy for large scale databases. The traditional hash-partitioned join methods such as the Hybrid Hash Join Method assume that the size of each bucket can be controlled by selecting a split function, and the characteristics of the buckets are statically(More)
In this paper, we show detailed analysis and performance evaluation of the Dynamic Hybrid GRACE Hash Join Method (DHGH Method) when the tuple distribution in buckets is unbalanced. The conventional Hash Join Methods specify the tuple distribution in buckets statically. However it may differ from estimation since join operations are applied with selection(More)
We have developed a system that streams and archives live sound from remote areas across Japan via an unmanned automatic camera. The system was used to carry out pilot bird censuses in woodland; this allowed us to examine the use of live sound transmission and the role of social media as a mediator in remote scientific monitoring. The system has been(More)
The Live E! project is an open research consortium among industry and academia to explore the platform to share the digital information related with the earth and our living environment. We have getting a lot of low cost sensor nodes with Internet connectivity. The deployment of broadband and ubiquitous networks will enable autonomous and global digital(More)
The Live E! project is an open research consortium among industry and academia to explore the platform to share the digital information related with the Earth and our living environment. We have getting a lot of low cost sensor nodes with Internet connectivity. The deployment of broadband and ubiquitous networks will enable autonomous and global digital(More)
This paper proposes the multldlmenslonal cluster lng technique called GKD-tree method which IS fully adaptive to both of tuple and query dlstrlbutlons The method 1s bdsed on the theoretical analysis of the performance of multldlmensional clustermg Its algorithm and perIormance are described It IS shown that GKD tree method can largely reduce the average(More)
In this paper, an approach has been proposed that makes the processing of join operation in database systems more efficient. In join operation processing relations that take part in the join process are required to be transferred to the main memory (RAM) from hard disk. In join operation processing when block nested loop algorithm is used to perform join(More)
Wireless mesh networks suffer from intermittent connectivity, and thus hop-by-hop reliability and parallel message propagation, which DTN researches have explored, can be applied to allow scalable message propagation over such challenged network environments. We implemented those communication schemes onto UTMesh - 50-node scale wireless mesh network(More)
This paper introduces a novel honeypot for web application. Recently, web applications have been the target of numerous cyber attacks. In order to catch up new vulnerabilities in the applications, using a honeypot system is a feasible solution. However, there remains difficulty for developing a lure-able, protect-able, and deception-able honeypot for web(More)