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排序方式: 共有611条查询结果,搜索用时 31 毫秒
31.
Hemmi H Yamashita S Nakayama T Nishino T 《Journal of Bioscience and Bioengineering》2002,93(5):515-518
It is known that 1-deoxy-D-xylulose taken up by Escherichia coli is used as the precursor of the compounds synthesized via the non-mevalonate pathway, such as isoprenoids, probably after conversion into 1-deoxy-D-xylulose 5-phosphate. In this report, we show that a novel phospho(enol) pyruvate-dependent phosphotransferase system catalyzes the uptake and phosphorylation of 1-deoxy-D-xylulose. 相似文献
32.
A new beta-agarase was purified from an agarolytic bacterium, Bacillus sp. MK03. The enzyme was purified 129-fold from the culture supernatant by ammonium sulfate precipitation, anion exchange and gel filtration column chromatographic methods. The purified enzyme appeared as a single band on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Estimation of the molecular mass by SDS-PAGE and gel filtration gave values of 92 kDa and 113 kDa, respectively. The N-terminal amino acid sequence of the enzyme showed no homology to those of other known agarases. The optimum pH and temperature for this enzyme were 7.6 and 40 degrees C, respectively. The predominant hydrolysis product of agarose by this enzyme was neoagarotetraose, indicating the cleavage of beta-1,4 linkage. This enzyme could hydrolyze neoagarohexaose to produce neoagarotetraose and neoagarobiose; it could not hydrolyze these products. The enzyme digested agarose by endo-type hydrolysis. 相似文献
33.
Fast agglomerative hierarchical clustering algorithm using Locality-Sensitive Hashing 总被引:1,自引:6,他引:1
Hisashi Koga Tetsuo Ishibashi Toshinori Watanabe 《Knowledge and Information Systems》2007,12(1):25-53
The single linkage method is a fundamental agglomerative hierarchical clustering algorithm. This algorithm regards each point
as a single cluster initially. In the agglomeration step, it connects a pair of clusters such that the distance between the
nearest members is the shortest. This step is repeated until only one cluster remains. The single linkage method can efficiently
detect clusters in arbitrary shapes. However, a drawback of this method is a large time complexity of O(n
2), where n represents the number of data points. This time complexity makes this method infeasible for large data. This paper proposes
a fast approximation algorithm for the single linkage method. Our algorithm reduces the time complexity to O(nB) by rapidly finding the near clusters to be connected by Locality-Sensitive Hashing, a fast algorithm for the approximate
nearest neighbor search. Here, B represents the maximum number of points going into a single hash entry and it practically diminishes to a small constant
as compared to n for sufficiently large hash tables. Experimentally, we show that (1) the proposed algorithm obtains clustering results similar
to those obtained by the single linkage method and (2) it runs faster for large data than the single linkage method.
Hisashi Koga received the M.S. and Ph.D. degree in information science in 1995 and 2002, respectively, from the University of Tokyo. From
1995 to 2003, he worked as a researcher at Fujitsu Laboratories Ltd. Since 2003, he has been a faculty member at the University
of Electro-Communications, Tokyo (Japan). Currently, he is an associate professor at the Graduate School of Information Systems,
University of Electro-Communications. His research interest includes various kinds of algorithms such as clustering algorithms,
on-line algorithms, and algorithms in network communications.
Tetsuo Ishibashi received the M.E. degree in information systems design from the Graduate School of Information Systems at the University
of Electro-Communications in 2004. Presently, he is a system engineer at Fujitsu Broad Solution & Consulting Inc.
Toshinori Watanabe received the B.E. degree in aeronautical engineering in 1971 and the D.E. degree in 1985, both from the University of Tokyo.
In 1971, he worked at Hitachi as a researcher in the field of information systems design. His experience includes demand forecasting,
inventory and production management, VLSI design automation, knowledge-based nonlinear optimizer, and a case-based evolutionary
learning system nicknamed TAMPOPO. He also engaged in FGCS (Fifth Generation Computer System) project of Japan and developed
a new hierarchical message-passing parallel cooperative VLSI layout problem solver that ran on PIM (Parallel Inference Machine)
in 1991. Since 1992, he has been a professor at the Graduate School of Information Systems, University of Electro-Communications,
Tokyo, Japan. His areas of interest include media analysis, learning intelligence, and the semantics of information systems.
He is a member of the IEEE. 相似文献
34.
Hidenobu Mizuki Yudai Ito Saba Samatya Hisashi Harada Hidetaka Kawakita 《溶剂提取与离子交换》2013,31(1):146-156
Abstract A novel adsorbent Zr(IV)-immobilized resin was prepared to remove fluoride ions from tap water and industrial wastewater. In order to enhance both the kinetics and efficiency, large pathways were formed in the resin for fluoride ion adsorption and the Zr(IV)-phosphate complexes were immobilized on the polymer surface by surface-template polymerization. The Zr(IV)-immobilized resin had a fluoride adsorption capacity of 0.30 mmol/g. The morphology of the Zr(IV)-immobilized resin was evaluated by measuring the specific surface area, pore volume, and pore size distribution. The resin possessed large amounts of large macropores with diameters around 300 nm. The molecular structure at the fluoride adsorption sites was investigated by measuring the amounts of phosphorus, zirconium, and fluoride ion in the resin, and developing a model complex using computational chemistry. On the polymer surface, a fluoride ion/Zr(IV)/dioleyl phosphoric acid complex with an ideal F:Zr:P mole ratio of 3:1:3 could be formed. 相似文献
35.
36.
Reinforcement learning (RL) attracts much attention as a technique for realizing computational intelligence such as adaptive
and autonomous decentralized systems. In general, however, it is not easy to put RL to practical use. This difficulty includes
the problem of designing a suitable action space for an agent, i.e., satisfying two requirements in trade-off: (i) to keep
the characteristics (or structure) of an original search space as much as possible in order to seek strategies that lie close
to the optimal, and (ii) to reduce the search space as much as possible in order to expedite the learning process. In order
to design a suitable action space adaptively, in this article, we propose a RL model with switching controllers based on Q-learning
and an actor-critic to mimic the process of an infant’s motor development in which gross motor skills develop before fine
motor skills. Then a method for switching controllers is constructed by introducing and referring to the “entropy.” Further,
through computational experiments by using a path-planning problem with continuous action space, the validity and potential
of the proposed method have been confirmed. 相似文献
37.
Hasegawa Tatsuro Yamauchi Hisashi Sashida Yoshio Matsumoto Mitsuo 《Industrial Electronics, IEEE Transactions on》1985,(3):253-260
Recent application of distributed control systems to large-and medium-scale industrial plants requires effective and high-speed communication among the control devices each other to ensure high-performance operation. 相似文献
38.
39.
40.
Kyung-Cho Kim Hiroaki Fukubara Hisashi Yamawaki Tetsuya Saito 《Journal of Mechanical Science and Technology》2001,15(1):52-60
In this paper, as a new measurement method to estimate the change of material condition, the simplified ultrasonic CT system,
which uses the information of three directions, that is, 90°, + 45° and −45° about inspection plane is proposed. Use of simplified
CT system has two merits: Firstly, the measurement time is very short compared with general CT. Secondly, it can detect sensitively
small defect in vertical or slant direction about inspection plane because the obtained image is CT image calculated from
three directions. From these merits, this method can be considered as an effective method to evaluate material conditions.
The basic performance of the proposed method was confirmed through several specimens with several simple defects. In order
to confirm the applicability of actual NDT, several kinds of welded specimens are investigated. The result showed that the
CT image obtained had good agreement with actual defect of specimens. 相似文献