• 대한화학회지
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• 제52권3호
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• pp.322-327
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• 2008

HOOCl-H2O cluster에 대하여 안정한 구조와 결합에너지를 MP2/6-311G(d,p), MP2/6-311G(2d,2p)의 방법으로 계산하였고 vibrational frequency계산을 하여 HOOCl의 vibrational frequency와 비교하였다. Skew HOOCl-H2O cluster가 가장 안정한 cluster로 나타났고 결합에너지는 46~48 kJ/mol 정도이며 trans HOOCl-H2O cluster의 경우도 이보다 불안정하나 비교적 큰 결합에너지를 갖는 것으로 나타났다.

• 한국식생활문화학회지
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• 제26권6호
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• pp.574-582
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• 2011

The aim of this study was to classify Korean consumers based on their food-related lifestyle type, and to investigate the relationship between sushi consumption and food-related lifestyle type. Self-reported questionnaires were completed by 300 Korean adults. The SPSS 18.0 program was used to analyze the samples. Data was analyzed by frequency, descriptive factor, reliability, cluster analysis, ANOVA, and chi-square test. A factor analysis extracted four factors comprising foodrelated lifestyle, which we named Health-seeking (factor 1), Taste-seeking (factor 2), Convenience-seeking (factor 3), and Economy-seeking (factor 4). According to a cluster analysis based on those four factors, consumers were classified into three clusters. Cluster 1 was the Taste and Health-seeking cluster, Cluster 2 was the Convenience-seeking cluster, and Cluster 3 was the Passive Eating Habits cluster. The results also indicated that the selection attributes of each cluster were significantly different in terms of perception, the global state of sushi, sushi preference, frequency, companions, place of sushi consumption, and preference for different sushi sub-ingredients. Based on these results, consumer characteristics in the sushi market are discussed.

• Journal of Electrical Engineering and Technology
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• 제13권2호
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• pp.998-1007
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• 2018

The advent of Wireless Sensor Networks (WSN) has led to their use in numerous applications. Sensors are autonomous in nature and are constrained by limited resources. Designing an autonomous topology with criteria for economic and energy conservation is considered a major goal in WSN. The proposed honey-hive clustering consumes minimum energy and resources with minimal transmission delay compared to the existing approaches. The honey-hive approach consists of two phases. The first phase is an Intra-Cluster Min-Max Discrepancy (ICMMD) analysis, which is based on the local honey-hive data gathering technique and the second phase is Inter-Cluster Frequency Matching (ICFM), which is based on the global optimal data aggregation. The proposed data aggregation mechanism increases the optimal connectivity range of the sensor node to a considerable degree for inter-cluster and intra-cluster coverage with an improved optimal energy conservation.

• Journal of Communications and Networks
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• 제13권6호
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• pp.655-663
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• 2011

Diffuse optical wireless (DOW) systems have the advantage that they do not require point-to-point siting so one transmitter can communicate with several receivers. In this paper, we investigate multiple access scheduling methods for downlink orthogonal frequency division multiplexing (OFDM) in diffuse optical wireless networks. Unlike the radio frequency (RF) channel, the DOW channel has low-pass filter characteristics and so requires different scheduling methods than those developed for the RF channel. Multi-user diversity orthogonal frequency division multiple access (OFDMA) systems nominate a cluster of subcarriers with the largest signal-to-noise-ratio for transmission. However, in a DOW channel, most users would choose the lowest frequency clusters of subcarriers. To remedy this problem, we make two proposals. The first is to use a variable cluster size across the subcarriers; the lower frequency clusters will have fewer subcarriers while the higher frequency clusters will have more subcarriers. This will equalize the capacity of the clusters. The second proposal is to randomize a user's cluster selection from a group of clusters satisfying a minimum threshold. Through simulation it is shown that combining these strategies can increase the throughput while ensuring a fair distribution of the available spectrum.

• Journal of Plant Biotechnology
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• 제30권3호
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• pp.241-244
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• 2003

Root cluster section culture, showing high efficient Protocorm-like body (PLB) formation capacity, were established in Doritaenopsis hybrids. Three types of root were obtained from excised shoots in 1/2MS medium containing different concentrations of NAA; \circled1normal roots, \circled2multiple roots and \circled3abnormal root clusters. Those were placed on 1/2MS medium supplemented with 0.5 mg/L thidiazuron for PLB regeneration. PLB regeneration rate was greater in root cluster section cultures (77.8%) compare to normal root tip cultures(30%). Number of PLBs regenerated from root cluster sections were counted over 11 per explant (5.3 per normal root tip).High frequency of PLB regeneration was achieved in root cluster section culture. This result can be used as an efficient method for clonal proliferation of Doritaenopsis hybrids.

• 대기
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• 제17권1호
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• pp.45-53
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• 2007

In order to investigate the impacts of heat wave on human health, cluster analysis of meteorological elements (e.g., temperature, dewpoint, sea level pressure, visibility, cloud amount, and wind components) for identifying offensive synoptic air masses is employed. Meteorological data at Seoul during the past 30 years are used. The daily death data at Seoul are also employed. Occurrence frequency of heat waves which is defined by daily maximum temperature greater than the threshold temperature (i.e., $31.2^{\circ}C$) was analyzed. The result shows that the frequency and duration of heat waves at Seoul are increasing during the past 30 years. In addition, the increasing trend of the frequency and duration clearly appears in late spring and early autumn as well as summer. Factor analysis shows that 65.1% of the total variance can be explained by 4 components which are linearly independent. Eight clusters (or synoptic air masses) were classified and found to be optimal for representing the summertime air masses at Seoul, Korea. The results exhibit that cluster-mean values of meteorological variables of an offensive air mass (or cluster) are closely correlated with the observed and standardized deaths.

• 인지과학
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• 제18권4호
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• pp.325-350
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• 2007

본 연구에서는 대학생 독자들이 48개의 평이한 문장을 읽을 때, 전반적인 안구 운동의 특성과 어절/단어 수준에서의 특성을 알아보았다 대학생 독자들은 어절을 대략 225ms 보다가 3.6자 정도 뛰어 다음 어절로 눈을 움직였다. 어절이 짧고 단어가 고빈도일 때는 어절을 건너뛰기도 하고, 앞으로만 읽어가는 것이 아니라 19% 정도 다시 되돌아가서 읽기도 했다. 물론 고정과 도약의 양상은 독자에 따라 개인차가 있었다. 이런 전반적인 양상과 더불어, 어절 수준에서 어절 길이, 단어 빈도 및 착지점 관련 효과를 살펴보았는데, 눈은 대체로 어절의 중앙에 자주 착지했으며, 가장자리에 착지했을 때가 중앙에 착지할 때보다 그 어절을 다시 더 고정했다. 또한 독자들은 단어가 고빈도인 어절을 저빈도인 어절보다 훨씬 빨리 읽었다.

• 한국환경과학회지
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• 제24권6호
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• pp.793-806
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• 2015

The purpose of this study is to find out the air flow patterns affecting the PM10 concentration in Busan and the potential sources within each trajectory pattern. The synoptic air flow trajectories are classified into four clusters by HYSPLIT model and the potential sources of PM10 are estimated by PSCF model for each cluster from 2008 to 2012. The potential source locations of PM10 are compared with the distribution of PM10 anthropogenic emissions in east Asia developed in 2006 for the NASA INTEX-B mission. The annual mean concentrations of PM10 in Busan decreased from $51ug/m^3$ in 2008 to $43ug/m^3$ in 2012. The monthly mean concentrations of PM10 were high during a spring season, March to May and low during a summer season, August and September. The cluster2 composed of the air trajectories from the eastern China to Busan through the west sea showed the highest frequency, 44 %. The cluster1 composed of the air trajectories from the inner Mongolia region to Busan through the northeast area of China showed the second high frequency, 26 %. The cluster3 and 4 were composed of the trajectories originated in the southeast sea and the east sea of Busan respectively and showed low frequencies. The concentrations of in each cluster were $47ug/m^3$ in cluster1, $56ug/m^3$ in cluster2, $42ug/m^3$ in cluster3 and $37ug/m^3$ in cluster4. From these results, it was proved that the cluster1 and 2 composed of the trajectories originated in the east and northeast area of China were the causes of high PM10 concentrations in Busan. The results of PSCF and CWT model showed that the potential sources of the high PM10 concentrations were the areas of the around Mongolia and the eastern China having high emissions of PM10 from Beijing, Hebei to Shanghai through Shandong, Jiangsu.

• International Journal of Advanced Culture Technology
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• 제5권3호
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• pp.40-45
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• 2017

This data mining technique was used to extract useful information from percutaneous coronary intervention data obtained from the US public data homepage. The experiment was performed by extracting data on the area, frequency of operation, and the number of deaths. It led us to finding of meaningful correlations, patterns, and trends using various algorithms, pattern techniques, and statistical techniques. In this paper, information is obtained through efficient decision tree and cluster analysis in predicting the incidence of percutaneous coronary intervention and mortality. In the cluster analysis, EM algorithm was used to evaluate the suitability of the algorithm for each situation based on performance tests and verification of results. In the cluster analysis, the experimental data were classified using the EM algorithm, and we evaluated which models are more effective in comparing functions. Using data mining technique, it was identified which areas had effective treatment techniques and which areas were vulnerable, and we can predict the frequency and mortality of percutaneous coronary intervention for heart disease.

• 천문학회보
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• 제41권2호
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• pp.59.1-59.1
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• 2016

Blue Straggler Stars(BSS) affect their host star cluster in various parameters like color, dynamics, etc. For this reason, it is important to know how to relate BSS frequency and evolution of their host stellar system. To statistical study about global properties of open clusters as the environments of BSS formation, we use three catalogues - (1) two galactic open clusters catalogues including BSS candidate, (2) Milky Way Star Cluster (MWSC) survey data. Then, we compare with the data of two BSS catalogues for test of the result of Marchi et al. 2006. We also investigate the radial mass distribution in open cluster, because it is possible that changing the gradient of radial mass distribution cause increasing the BSS frequency. When we group the open cluster into having BSS or not and other criteria, the groups show slight discrepancies, but we show some important results.