• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.469-471
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• 2015

How galaxies are affected by their neighboring galaxies during galaxy-galaxy interactions is a long-standing question. We investigate the role of neighbors in galaxy pairs based on the SDSS data release 7 and the KIAS value-added galaxy catalog. Three groups of galaxies are identified: (a) galaxies with an early-type neighbor, (b) with a late-type neighbor, and (c) isolated ones with no neighbor. We compare their UV + optical colors and $H{\alpha}$ emission as indicators of the recent star-formation rate (SFR). Given that galaxies show systematic differences in SFR as functions of morphology, luminosity, and large-scale environments, we construct a control sample in which the galaxies have the same conditions (in terms of morphology, luminosity, and large-scale environment) except for the neighbor's properties (i.e., morphology, mass, and distance). The results are as follows. (1) Galaxies with a late-type companion demonstrate more enhanced SFR than those with an early-type companion. (2) Galaxies with an early-type neighbor show NUV- and u-band derived SFRs that are even lower than that of isolated galaxies, while they have similar or slightly higher $H{\alpha}$-based SFR compared to isolated ones.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.3
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• pp.52-58
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• 2002

The purpose of condition monitoring and fault diagnosis is to detect faults occurring in machinery in order to improve the level of safety in plants and reduce operational and maintenance costs. The recognition performance is important not only to gain a high recognition rate bur a1so to minimize the diagnosis failures error rate by using off effective rejection module. We examined the problem of performance evaluation for the rejection scheme considering the accuracy of individual c1asses in order to increase the recognition performance. We use the Smith's method among the previous studies related to rejection method. Nearest neighbor classifier is used for classifying the machine conditions from the vibration signals. The experiment results for the performance evaluation of rejection show the modified optimum rejection method is superior to others.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.75.2-75.2
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• 2010

We investigate the dependence of occurrence of bar in galaxies on galaxy properties and environment. The environmental conditions considered include the large-scale background density and distance to the nearest neighbor galaxy. We use a volume-limited sample of 33,296 galaxies brighter than $M_r$=-19.5+5logh at $0.02{\leqq}z{\leqq}0.05489$, drawn from the Sloan Digital Sky Survey Data Release 7. We classify the galaxies into early and late types, and identify bars by visual inspection. We find that the fraction of barred galaxies ($f_{bar}$) is 18.2% on average in the case of late-type galaxies, and depends on both u-r color and central velocity dispersion $(\sigma);f_{bar}$ is a monotonically increasing function of u-r color, and has a maximum value at intermediate velocity dispersion (${\sigma}{\simeq}170km\;s^{-1}$). This trend suggests that bars are dominantly hosted by systems having intermediate-mass with no recent interaction or merger history. We also find that $f_{bar}$ does not directly depend on the large-scale background density as its dependence disappears when other physical parameters are fixed. We discover the bar fraction decreases as the separation to the nearest neighbor galaxy becomes smaller than 0.1 times the virial radius of the neighbor regardless of neighbor's morphology. These results imply that it is difficult for bars to be maintained during strong tidal interactions, and that the source for this phenomenon is gravitational and not hydrodynamical.

• ALGAE
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• v.17 no.1
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• pp.41-51
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• 2002

Three dominant rocky intertidal macroalgae, the fucoids Fucus gardneri and Pelvetiopsis limitata (Phaeophyta) and the red alga Mazzaella cornucopiae (= Iridaea cornucopiae) on the west coast of Vancouver Island, British Columbia, Canada were used in a series of field experiments to examine interspecific interactions. These experiments showed complex patterns which included an interchange of negative (inhibition) and positive (facilitation) interactions depending on neighbor distance. Less fucoid recruitment occurred in the plots with greater percent cover of a turfforming red alga, M. cornucopiae. However, experimentally removing Mazzaella turf (the turf was considered to be "blocking" fucoid recruits or "shading" growing recruits) did not increase recruitment. This result indicated that there may be another factor(s) involved in the survivorship of juvenile fucoids in the turf-removed plots. Morphological differences in adult plants between Mazzaella and the two fucoids resulted in another type of interaction; these began when fucoids successfully settled and grew nearby or within the red algal turf. By monitoring microhabitat at the individual plant level for two years, I found that survivorship of fucoid recruits showed different species-specific patterns. The patterns also varied as the microhabitat changed from Mazzaella turf edge to open space. For F. gardneri, longevity of P.limitata at all distances tested was similar. A reason for greater longevity of F. gardneri individuals at edge microhabitats may be that these sites have one side open to light and nutrients and another site that buffers them from desiccation and wave impact. In the Mazzaella-Fucus interaction, neighbor distance was a key factor in determining whether the outcome of the interaction would be competition or facilitation (or protection). This study provides experimental evidence that detectable biological interactions occur in this upper intertidal algal community where physical conditions are usually severe, and also indicates the importance of small scale examination in understanding macroalgal interactions in intertidal habitats.

• Journal of the Korea Society of Computer and Information
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• v.26 no.4
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• pp.63-74
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• 2021

Location-based services (LBSs) are expected to process a large number of spatial queries, such as shortest path and k-nearest neighbor queries that arrive simultaneously at peak periods. Deploying more LBS servers to process these simultaneous spatial queries is a potential solution. However, this significantly increases service operating costs. Recently, batch processing solutions have been proposed to process a set of queries using shareable computation. In this study, we investigate the problem of batch processing moving k-nearest neighbor (MkNN) queries in dynamic spatial networks, where the travel time of each road segment changes frequently based on the traffic conditions. LBS servers based on one-query-at-a-time processing often fail to process simultaneous MkNN queries because of the significant number of redundant computations. We aim to improve the efficiency algorithmically by processing MkNN queries in batches and reusing sharable computations. Extensive evaluation using real-world roadmaps shows the superiority of our solution compared with state-of-the-art methods.

• Proceedings of the KSPS conference
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• 2002.11a
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• pp.97-100
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• 2002

The purpose of this paper is to investigate the unit of neighbor of Korean words. In English, a word's orthographic neighborhood is defined as the set of words that can be created by changing one letter of the word while preserving letter positions. For example, the words like pike, pole, and tile are all orthographic neighbors of the word 'pile'. In this study, 2 experiments were performed. In these experiments, 4 conditions of prime were included: primes sharing first letter of first syllable(1), first syllable(2), first syllable and the first letter of second syllable with target(3) and with no formal similarity with target(4). In Exp.1, RT was shortest in condition 3. In Exp.2, condition 2 had the shortest RT. We came to the conclusion that in Korean, a word's neighbor is words that share at least one syllable with the word.

• Journal of Information Processing Systems
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• v.15 no.6
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• pp.1392-1405
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• 2019

The cathode voltage of aluminum electrolytic cell is relatively stable under normal conditions and fluctuates greatly when it has an anomaly. In order to detect the abnormal range of cathode voltage, an anomaly detection algorithm based on sliding window was proposed. The algorithm combines the time series segmentation linear representation method and the k-nearest neighbor local anomaly detection algorithm, which is more efficient than the direct detection of the original sequence. The algorithm first segments the cathode voltage time series, then calculates the length, the slope, and the mean of each line segment pattern, and maps them into a set of spatial objects. And then the local anomaly detection algorithm is used to detect abnormal patterns according to the local anomaly factor and the pattern length. The experimental results showed that the algorithm can effectively detect the abnormal range of cathode voltage.

• Journal of the Korean Home Economics Association
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• v.40 no.12
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• pp.171-187
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• 2002

The purpose of this study ws6 to find out women's informationized conditions and their life changes. The subjects of this research were 482 women living in large and small-medium sized cities. The data analysis used average, pearson's correlation, one-way ANOVA and multiple regression by SAS/PC. The major findings were as follows: 1. Women's level of informationized conditions is under median in computer using and information technology. The effect of informatization is over median about improving the ability, recognizing from family and neighbor, achieving the occupation. The change of individual and family is under median except educational stimulus, life vitality and educational effect on the family. 2. The effect of informatization was influenced by ability of using computer, necessity and purpose of informatization. The change of individual was influenced by ability of using computer, purpose and effect of informatization and also the change of family was influenced by handicapped reason in information education and the effect of informatization.

• The Journal of the Korea Contents Association
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• v.9 no.8
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• pp.57-63
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• 2009

Object recognition technologies using PCA(principal component analysis) recognize objects by deciding representative features of objects in the model image, extracting feature vectors from objects in a image and measuring the distance between them and object representation. Given frequent recognition problems associated with the use of point-to-point distance approach, this study adopted the k-nearest neighbor technique(class-to-class) in which a group of object models of the same class is used as recognition unit for the images in-putted on a continual input image. However, the robustness of recognition strategies using PCA depends on several factors, including illumination. When scene constancy is not secured due to varying illumination conditions, the learning performance the feature detector can be compromised, undermining the recognition quality. This paper proposes a new PCA recognition in which database of objects can be detected under different illuminations between input images and the model images.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.5B
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• pp.274-286
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• 2005

In this paper, we propose a new power-efficient and reliable connected dominating set based routing protocol in the mobile ad hoc networks. Gateway nodes must be elected in consideration of residual energy and mobility because frequent reconstruction of connected dominating set result in transmission error for route losses. If node density is high, it results in a lot of contentions and more delays for network congestion. Therefore, in this paper, we propose a new construction method of connected dominating set that supports reliable and efficient data transmission through minimizing reconstruction of connected dominating set by delaying neighbor set advertisement message broadcast in proportion to weighted sum of residual energy, mobility, and the number of neighbor nodes. The performance of the proposed protocol is proved by simulation of various conditions.