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Scalable Multiple NameNodes Hadoop Cloud Storage System
Kun Bi,Dezhi Han 보안공학연구지원센터 2015 International Journal of Database Theory and Appli Vol.8 No.1
To solve the problem that the total number of files in HDFS is limited by the memory size of the NameNode, the paper proposed a scalable multiple NameNodes coexisting scheme for cloud storage. NameNode location service (NLS) was introduced into the system. NLS communicated with all NameNodes and was responsible for the file location requests from the clients. Experimental results showed this scheme had good scale-out scalability and the upper limit of the total number of files that the system was able to store could be greatly increased by adding a number of NameNodes.
A New Method of Point-Clouds Accurate Measurement and Reconstruction
Kun Zhang,Weihong Bi,Xinghu Fu 보안공학연구지원센터 2014 International Journal of Database Theory and Appli Vol.7 No.6
With the reverse engineering development, the accuracy of system is more important in reconstruction, especially in non-contacting measurement. This paper provides a new method measuring the accuracy the point clouds, define a image probability and the point probability according to uncertainty data. The quantity of the uncertain point data is important to measuring the result of reconstruction. The prior data can be catch from the last measurement process, especially the edge data or characteristic points. Referring to prior data, basing on the Bayesian theory the more accuracy posterior data can be computed in this paper. We divided the point cloud into different areas, and organized the data with hierarchical tree-structure. According to the probability of one tree node, we adjust the area corresponding to the node. At last, by using the existing experimental equipment, we verify the measurement of point cloud accuracy algorithm. The depth data was obtained by a laser scanner---SICK LMS100. The depth data can be computed as point data with uncertainty. The result of the reconstruction deeply relies on the quality of prior data.
Acoustic Noise of Brushless DC Motors Induced by Electromagnetic Torque Ripple
Kun Xia,Zhengrong Li,Jing Lu,Bin Dong,Chao Bi 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.4
Torque ripple is one of the major sources inducing vibration and noise in brushless DC motors. This is especially true in applications such as the spindle motors used in hard disk drives. However, the relationship between torque ripple and acoustic noise/vibration is quite complicated. This paper presents a way to investigate this relationship with acoustic noise measurement and analysis. Results obtained with three different drive modes are used in the analysis. The results show that the acoustic noise analysis is very helpful in designing a high-performance drive strategy for BLDC motors.
A New Kmeans Clustering Algorithm for Point Cloud
Kun Zhang,Weihong Bi,Xiaoming Zhang,Xinghu Fu,Li Zhu,Kunpeng Zhou 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.9
With development of 3D scanner, it becomes more convenient to access point data. However, for processing the large-scale point cloud, it raised a new challenge for computer graphics. This paper places an emphasis on the point data own characteristics, and then the point data have been divided into certain point sets by clustering algorithm, that is will be divided into different clusters. In order to suit for the point data organization or space division, the clustering algorithm would be improved. This paper provided a new Kmeans algorithm with density constraints. Before processing the point cloud by Kmeans algorithm with density constraints, the density of the point cloud have been defined in this paper, the density of the point cloud can be used for quantification of the convergence. Finally, the Kmeans algorithm with density constraints is verified by the experiment results. Our experiment showed that the improved Kmeans can reduce the processing time, especially, As the increase of the value of K, that is number of cluster, the calculating time of the clustering algorithm can be decreased greatly. In addition, with the increases of the the scale of data size, the stability of the improved Kmeans algorithm has been verified.
( Eun-bi Jeong ),( Se-a Kim ),( Kyung-chul Shin ),( Deok-kun Oh ) 한국미생물 · 생명공학회 2020 Journal of microbiology and biotechnology Vol.30 No.10
Compound K (C-K) is one of the most pharmaceutically effective ginsenosides, but it is absent in natural ginseng. However, C-K can be obtained through the hydrolysis of protopanaxadiol-type ginsenosides (PPDGs) in natural ginseng. The aim of this study was to obtain the high concentration of food-available C-K using PPDGs in Korean ginseng extract by an extracellular enzyme from Aspergillus niger KACC 46495. A. niger was cultivated in the culture medium containing the inducer carboxymethyl cellulose (CMC) for 6 days. The extracellular enzyme extracted from A. niger was prepared from the culture broth by filtration, ammonium sulfate, and dialysis. The extracellular enzyme was used for C-K production using PPDGs. The glycoside-hydrolyzing pathways for converting PPDGs into C-K by the extracellular enzyme were Rb1 → Rd → F2 → C-K, Rb2 → Rd or compound O → F2 or compound Y → C-K, and Rc → Rd or compound Mc1 → F2 or compound Mc → C-K. The extracellular enzyme from A. niger at 8.0 mg/ml, which was obtained by the induction of CMC during the cultivation, converted 6.0 mg/ml (5.6 mM) PPDGs in Korean ginseng extract into 2.8 mg/ml (4.5 mM) food-available C-K in 9 h, with a productivity of 313 mg/l/h and a molar conversion of 80%. To the best of our knowledge, the productivity and concentration of C-K of the extracellular enzyme are the highest among those by crude enzymes from wild-type microorganisms.
Acoustic Noise of Brushless DC Motors Induced by Electromagnetic Torque Ripple
Xia, Kun,Li, Zhengrong,Lu, Jing,Dong, Bin,Bi, Chao The Korean Institute of Power Electronics 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.4
Torque ripple is one of the major sources inducing vibration and noise in brushless DC motors. This is especially true in applications such as the spindle motors used in hard disk drives. However, the relationship between torque ripple and acoustic noise/vibration is quite complicated. This paper presents a way to investigate this relationship with acoustic noise measurement and analysis. Results obtained with three different drive modes are used in the analysis. The results show that the acoustic noise analysis is very helpful in designing a high-performance drive strategy for BLDC motors.
Two New α-Pyrones and Other Components from the Cladodes of Opuntia dillenii
Ying Kun Qiu,Yan Yan Zhao,De Qiang Dou,Bi Xia Xu,Ke Liu 대한약학회 2007 Archives of Pharmacal Research Vol.30 No.6
The aqueous ethanolic extract from the fresh cladodes of Opuntia dillenii HAW. was found to show anti-inflammatory activity. Two new α-pyrones, named opuntioside II (1) and opuntioside III (2), were isolated from the extract together with six known compounds. The structures of the new compounds were determined on the basis of chemical and physicochemical evidence.