- 著者
- Mehedi Masud Gopal Chandra Das Anisur Rahman Arunashis Ghose
- 出版者
- CODATA
- 雑誌
- Data Science Journal (ISSN:16831470)
- 巻号頁・発行日
- vol.5, pp.143-161, 2006 (Released:2006-11-28)
- 参考文献数
- 11
It is always a major demand to provide efficient retrieving and storing of data and information in a large database system. For this purpose, many file organization techniques have already been developed, and much additional research is still going on. Hashing is one developed technique. In this paper we propose an enhanced hashing technique that uses a hash table combined with a binary tree, searching on the binary representation of a portion the primary key of records that is associated with each index of the hash table. The paper contains numerous examples to describe the technique. The technique shows significant improvements in searching, insertion, and deletion for systems with huge amounts of data. The paper also presents the mathematical analysis of the proposed technique and comparative results.
- 著者
- Hiromichi Itoh Hiroaki Okaya Anisur Rahman Khan Shigeyuki Tajima Shigeru Hayakawa Ken Izumori
- 出版者
- (社)日本農芸化学会
- 雑誌
- Bioscience, Biotechnology, and Biochemistry (ISSN:09168451)
- 巻号頁・発行日
- vol.58, no.12, pp.2168-2171, 1994-12-23 (Released:2008-02-08)
- 参考文献数
- 11
- 被引用文献数
- 41 137
A new enzyme, D-tagatose 3-epimerase, was found in Pseudomonas sp. ST-24 during the course of studies on D-sorbose fermentation. This new enzyme catalyzes epimerization of keto-sugars, for example between D-tagatose and D-sorbose, and between D-fructose and D-psicose. It was shown that this enzyme epimerizes the configuration at the C-3 position of these substrates. This epimerase didn't act on D-fructose 6-phosphate and D-ribulose 5-phosphate. The enzyme has been purified from cells grown on a medium containing 1% D-glucose and 0.05% D-tagatose, and it appeared homogeneous on electrophoresis. The enzyme has a molecular weight of about 68, 000 by gel filtration and consists of two subunits identical in molecular weight (about 33, 000 by SDS-PAGE). The maximum activity at 30°C was obtained at pH 7-9, and the enzyme was stable from pH 7-11. The optimum temperature was around 60°C, and it was stable up to 60°C for 10 min.