• Journal of Astronomy and Space Sciences
• /
• v.11 no.2
• /
• pp.147-153
• /
• 1994

We present a deep(B, V) color-magnitude diagram (CMD) of the Galactic globular cluster NGC 4372. According to the recent inside-out picture of Galaxy formation, this cluster is predicted to be one of the oldest globulat clusters in the Galaxy. Our CMD shows a well defined main-sequence extending ∼ 2 magnitudes below the trunoff. Despite the uncertainty that stems from the small sample size of bright stars, comparison with the Revised Yale Isochrones suggests that this cluster may indeed be one of the oldest (∼16.6 Gyrs) globular clusters in our Galaxy.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.18 no.2
• /
• pp.361-366
• /
• 2023

Apache Hadoop, a representative framework for distributed processing of big data, has the advantage of increasing cluster size up to thousands of nodes to improve parallel distributed processing performance. However, reducing the size of the cluster is limited to the extent of permanently decommissioning nodes with defects or degraded performance, so there are limitations to operate multiple nodes flexibly in small clusters. In this paper, we discuss the problems that occur when removing nodes from the Hadoop cluster and propose a dynamic down-scaling technique to manage the distributed cluster more flexibly. To do this, we design and implement a modified Hadoop system and interfaces to support dynamic down-scaling of the cluster which supports temporary pause of a node and reconnection of it when necessary, rather than decommissioning the node when removing a node from the Hadoop cluster. We have verified that effective downsizing can be performed without performance degradation based on experimental results.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.18 no.2
• /
• pp.211-220
• /
• 1994

The purpose of this study was to analyze the foot type by cluster analysis for footwear. The sample size for the study was 200 college womens between age 19 and 23 in Pusan urban area. There were measured 17 items of the foot for factor analysis and cluster analysis. The result was as follows : 1. 1'here were 9 items selected by factor analysis. 2.'rho cluster analysis of the foot must be analyzed by direct and indirect measurement indivisually. 3. The cluster analysis of the direct measurement ; Cluster 1 : 1'he foot length is all much the same to mean value of this age group and the items of width and circumference are relatively small to other clusters. Cluster 2 ; The foot length is relatively small to other clusters and the items of width and circumference are all much the same to mean value of this age group. Cluster 3 ; The foot sine Is relatively large to other clusters. 4. The cluster analysis of indirect measurement ; Cluster 1 ; The (cot print angle is high find Metatarso-Phalanx angle is transformed Cluster 2 ; The foot print angle is low and Melatarso-Phalanx angle is normal. Cluster 3 : Tho foot print angle Is middle and Metatarso-Phalanx angle is all the mush same to mean value of this age group. Cluster 4 . The foot print angle Is the most value and Metatarso-Phalanx angle is normal.

• Journal of the Korean Society of Costume
• /
• v.36
• /
• pp.43-52
• /
• 1998

This study was to analyze properties of the foot form through a development figure of the surface area by factor analysis, cluster analysis, and reglation analysis. This study was performed 71 college women between 19 adn 23 years old residing in Pusan urban area. The result was as follows; 1. There are four factors selected by factor analysis. The 1st factor signifies the surface area of the toe. The 2nd factor signifies the surface area between Metatarsal circumfer-ence and Tarsal circumference. The 3rd factor signifies the surface area between Toe circumference and Metatarsal circumference. The 4th factor signifies the surface area between Heel-ankle circumference. 2. There are three clusters selected by fast cluster. Cluster 1 : The foot size, most parts of foot surface area and total foot surface area are relatively small to other clusters, but the surface area between Metatarsal circumference and Tarsal circumference is relatively large to other clusters. Cluster 2 : The foot size, all parts of foot surface area and total foot surface area are relatively large to other clusters as Cluster 1, but the surface area of the sole of the heel and the ankle is relatively large to other clusters. 3. Total surface area of the foot=-274.94+24.01* Foot lengh+9.28*Metatarsal circumference.

• Journal of Korean Society for Atmospheric Environment
• /
• v.23 no.6
• /
• pp.752-759
• /
• 2007

For an accurate measurement of aerosol particle size distribution using a differential mobility analyser (DMA), a new calculation process, capable of predicting the masses for the various kinds of water cluster ions generated from a bipolar ionizer, was prepared by improving the previous process. The masses for the 5 kinds of positive and negative water cluster ions produced from a SMAC ionizer were predicted by the improved calculation process. The aerosol particle charging ratios calculated by applying the predicted ion masses to particle charging equations were in good accordance with the experimentally measured ones, indicating that the improved calculation process are more reasonable than the previous one in a mass prediction of bipolar water cluster ions.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.16 no.1
• /
• pp.19-24
• /
• 2021

In this paper, we study performance factor of machine learning in the distributed environment using Apache Spark and presents an efficient distributed processing method through experiments. This work firstly presents performance factor when performing machine learning in a distributed cluster by classifying cluster performance, data size, and configuration of spark engine. In addition, performance study of regression analysis using Spark MLlib running on the Hadoop cluster is performed while changing the configuration of the node and the Spark Executor. As a result of the experiment, it was confirmed that the effective number of executors was affected by the number of data blocks, but depending on the cluster size, the maximum and minimum values were limited by the number of cores and the number of worker nodes, respectively.

• Journal of the Korean earth science society
• /
• v.38 no.5
• /
• pp.333-344
• /
• 2017

We present the environmental dependence of the luminosity-size relation of galaxies in the local universe (z < 0.01) along with their dependence on galaxy morphology represented by five broad types (E, dEs, S0, Sp, and Irr). The environmental parameters we consider are the local background density and the group/cluster membership together with the clustercenteric distance for the Virgo cluster galaxies. We derive the regression coefficient (${\beta}$), i.e., the slope of the line representing the least-squares fitting to the data and the Pearson correlation coefficient (c.c.) representing the goodness of the least-squares fit along with the confidence interval from bootstrap resampling. We find no significant dependence of the luminosity-size relation on galaxy morphology. However, there is a weak dependence of the luminosity-size relations on the environment of galaxies, in the sense that galaxies in the low density environment have shallower slopes than galaxies in the high density regions except for elliptical galaxies that show an opposite trend.

• The KIPS Transactions:PartC
• /
• v.12C no.6 s.102
• /
• pp.875-880
• /
• 2005

One of the most important issues in the sensor network with resource-constrained sensor nodes is prolonging the network lifetime by efficiently utilizing the given energy of nodes. The most representative mechanism to achieve a long-lived network is the clustering mechanism. In this paper, we propose a new dynamic-size multi-hop clustering mechanism in which the burden of a node acting as a cluster head(CH) is balanced regardless of the density of nodes in a sensor network by adjusting the size of a cluster based on the information about the communication load and the residual energy of the node and its neighboring nodes. We show that our proposed scheme outperforms other single-hop or fixed-size multi-hop clustering mechanisms by carrying out simulations.

• Bulletin of the Korean Chemical Society
• /
• v.14 no.5
• /
• pp.578-583
• /
• 1993

By including the overlap integrals between atomic orbitals, the modified cluster orbitals for a metal cluster of face centered cubic lattice are found. The modified analytic solutions of the cluster are obtained from them with the assumption that the cluster orbitals with different state indices do not mix together. The physical properties-the HOMO levels and the unit electronic energies-of Ni, Pd, and Pt clusters of various size, calculated by the modified cluster orbital method, agree better with the results obtained by the Extended Huckel calculation than those of the previous(unmodified) cluster orbital method do. As a result, it is verified that the physical properties, at least those related to the energy levels, obtained by the Extended Huckel method may be reproduced by use of the modified cluster orbital method instead.

• International Journal of Computer Science & Network Security
• /
• v.22 no.7
• /
• pp.157-164
• /
• 2022

The proposed privacy preserving scheme has identified the drawbacks of existing schemes in Vehicular Networks. This prototype enhances the number of nodes by decreasing the cluster size. This algorithm is integrated with the whale optimization algorithm and Block Chain Technology. A set of results are done through the NS-2 simulator in the direction to check the effectiveness of proposed algorithm. The proposed method shows better results than with the existing techniques in terms of Delay, Drop, Delivery ratio, Overhead, throughout under the denial of attack.