• Child Studies in Asia-Pacific Contexts
• /
• v.6 no.2
• /
• pp.59-72
• /
• 2016

We examined the relationship between the extent of Facebook usage and social well-being with consideration of cyberbullying involvement using a person-oriented approach. Survey data were collected from a sample of 312 secondary students from Grades 7 and 8 in Hong Kong. Levels of cyberbullying involvement, Facebook usage and perceived social support were investigated. Participants were classified into three clusters based on the different levels of Facebook usage and cyberbullying victimization through cluster analyses (i.e., frequent Facebook user/noncyberbullied victim, frequent Facebook user/cyberbullied victim, and uninvolved). Our results showed that frequent Facebook users who are cyberbullied tend to engage in cyberbullying perpetration significantly more than the frequent Facebook users who are not cyberbullied, even when the latter reported higher Facebook usage. This result provides some support for the idea that cyberbullying victimization has additional value on top of the level of usage in explaining one's participation in cyberbullying perpetration. As expected, frequent Facebook users who were not cyberbullied reported the highest perceived social support among the three groups. What is even more interesting is the equal level of perceived social support found between the cyberbullied victims and the uninvolved. Our results suggest that, although limiting adolescents' Internet use might reduce their risks of being involved in cyberbullying, it might also take away the potential benefits they could get from interacting with the online community. Benefits of using the person-oriented approach in the study of cyberbullying are discussed.

• The Journal of the Convergence on Culture Technology
• /
• v.10 no.3
• /
• pp.461-466
• /
• 2024

Korean local governments operates the participatory budgeting system autonomously. This study is to classify these entities into clusters. Among the diverse machine learning methodologies(Neural Network, Rule Induction(CN2), KNN, Decision Tree, Random Forest, Gradient Boosting, SVM, Naïve Bayes), the Support Vector Machine technique emerged as the most efficacious in the analysis of 2022 Korean municipalities data. The first cluster C1 is characterized by minimal committee activity but a substantial allocation of participatory budgeting; another cluster C3 comprises cities that exhibit a passive stance. The majority of cities falls into the final cluster C2 which is noted for its proactive engagement in. Overall, most Korean local government operates the participatory busgeting system in good shape. Only a small number of cities is less active in this system. We anticipate that analyzing time-series data from the past decade in follow-up studies will further enhance the reliability of classifying local government types regarding participatory budgeting.

• The KIPS Transactions:PartB
• /
• v.18B no.2
• /
• pp.67-72
• /
• 2011

Single nucleotide polymorphisms (SNPs) are a very important tool for the study of human genome structure. Cluster analysis of the large amount of gene expression data is useful for identifying biologically relevant groups of genes and for generating networks of gene-gene interactions. In this paper we compared the clusters of SNPs within asthma group and normal control group obtained by using hierarchical cluster analysis method with entropy distance. It appears that the 5-cluster collections of the two groups are significantly different. We searched the best set of SNPs that are useful for diagnosing the two types of asthma using representative SNPs of the clusters of the asthma group. Here support vector machines are used to evaluate the prediction accuracy of the selected combinations. The best combination model turns out to be the five-locus SNPs including one on the gene ALOX12 and their accuracy in predicting aspirin tolerant asthma disease risk among asthmatic patients is 66.41%.

• Journal of Korean Elementary Science Education
• /
• v.33 no.4
• /
• pp.646-654
• /
• 2014

The aim of this study was to investigate the patterns of the elementary school students' interests to animals and plants based on affinity toward animals and plants, and curiosity about animals and plants by using a cluster analysis. In addition, the differences of the big five personality traits by the identified clusters was examined. A total number of 411 elementary school students participated in the study. The students were clustered into four distinct interest groups with respect to the level of interests to animals and plants. Cluster 1 'Developed Interest to Organisms group' showed high levels in the interest to both animals and plants. Cluster 2 'Developed Interest to Animals group' showed high interest to animals and relatively low interest to plants whereas cluster 3 'Developed Interest to Plants group' showed high interest to plants and relatively low interest to animals. Lastly, cluster 4 were identified as 'Lack of Interest to Organisms group' by showing low levels of interest to both animals and plants. The four identified groups also showed different distributions of students according to gender and school year. These results support gender difference in the interest to animals and plants and suggest the decreased and specialized interest with school year. The Big Five personality traits excluding neuroticism were positively related with the interest to organisms and the identified groups showed significant differences in the traits. These findings indicate that agreeableness, conscientiousness, extraversion, and openness can be significant predictors of the interests to animals and plants.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2003.11a
• /
• pp.73-78
• /
• 2003

In this research, we implement Realtime Air Diffusion Prediction System which is a parallel Fortran model running on distributed-memory parallel computers. The system is designed for air diffusion simulations with four-dimensional data assimilation. For regional air quality forecasting a series of dynamic downscaling technique is adopted using the NCAR/Penn. State MM5 model which is an atmospheric model. The realtime initial data have been provided daily from the KMA (Korean Meteorological Administration) global spectral model output. It takes huge resources of computation to get 24 hour air quality forecast with this four step dynamic downscaling (27km, 9km, 3km, and lkm). Parallel implementation of the realtime system is imperative to achieve increased throughput since the realtime system have to be performed which correct timing behavior and the sequential code requires a large amount of CPU time for typical simulations. The parallel system uses MPI (Message Passing Interface), a standard library to support high-level routines for message passing. We validate the parallel model by comparing it with the sequential model. For realtime running, we implement a cluster computer which is a distributed-memory parallel computer that links high-performance PCs with high-speed interconnection networks. We use 32 2-CPU nodes and a Myrinet network for the cluster. Since cluster computers more cost effective than conventional distributed parallel computers, we can build a dedicated realtime computer. The system also includes web based Gill (Graphic User Interface) for convenient system management and performance monitoring so that end-users can restart the system easily when the system faults. Performance of the parallel model is analyzed by comparing its execution time with the sequential model, and by calculating communication overhead and load imbalance, which are common problems in parallel processing. Performance analysis is carried out on our cluster which has 32 2-CPU nodes.

• ALGAE
• /
• v.17 no.1
• /
• pp.59-68
• /
• 2002

A phylogenetic affinity between charophytes and embryophytes (land plants) has been explained by a few chloroplast genomic characters including gene and intron (Manhart and Palmer 1990; Baldauf et al. 1990; Lew and Manhart 1993). Here we show that a charophyte, Spirogyra maxima, has the largest operon of angiosperm chloroplast genomes, rpl23 operon (trnⅠ-rpl23-rpl2-rps19-rpl22-rps3-rpl16-rpl14-rps8-infA-rpl36-rps11-rpoA) containing both embryophyte introns, rpl16.i and rpl2.i. The rpl23 gene cluster of Spirogyra contains a distinct eubacterial promoter sequence upstream of rpl23, which is the first gene of the green algal rpl23 gene cluster. This sequence is completely absent in angiosperms but is present in non-flowering plants. The results imply that, in the rpl23 gene cluster, early charophytes had at least two promoters, one upstream of trnⅠ and and another upstream of rpl23, which partially or completely lost its function in land plants. A comparison of gene clusters of prokaryotes, algal chloroplast DNAs and land plant cpDNAs indicated a loss of numerous genes in chlorophyll a+b eukaryotes. A phylogenetic analysis using presence/absence of genes and introns as characters produced trees with a strongly supported clade containing chlorophyll a+b eukaryotes. Spirogyra and embryophytes formed a clade characterized by the loss of rpl5 and rps9 and the gain of trnⅠ (CAU) and introns in rpl2 and rpl16. The analyses support the hypothesis that the rpl23 gene cluster and the rpl2 and rpl16 introns of land plants originated from a common ancestor of Spirogyra and land plants.

• Asian-Australasian Journal of Animal Sciences
• /
• v.19 no.6
• /
• pp.784-788
• /
• 2006

Microsatellite polymorphism and the genetic relationship were estimated using genotype information of 305 horses from 11 microsatellite loci. The breeds include the indigenous Korean breeds, Korean native horse (102) and Jeju racing horse (56) together with Japan Hokkaido horse (5), Mongolian horse (19), Thoroughbred horse (108), Quarter horse (11) and Przewalskii horse (4). Allelic frequencies, the number of alleles per locus were estimated by direct counting from observed genotype, and genetic variability was computed using the CERVUX software and DISPAN. The number of alleles per locus varied from 6 (HMS6) to 18 (ASB17) with an average value of 10.45 in horse breeds. The expected total heterozygosity ($H_T$) and coefficient of gene differentiation ($G_{ST}$) ranged 0.764-0.921 (the average value was 0.830) and 0.102-0.266 (the average value was 0.180) in horse breeds, respectively. Four populations (Przewalskii horse, Japan Hokkaido horse, Quarter horse, Thoroughbred horse) showed lower heterozygosity than the average value (the average value was 0.710). The expected heterozygosity within breed ($H_S$) and mean no. of observed alleles ranged from $0.636{\pm}0.064$ (Japan Hokkaido horse) to $0.809{\pm}0.019$ (Mongolian horse), and from 2.73 (Przewalskii horse) to 8.27 (Korean native horse), respectively. The polymorphic information content (PIC) ranged from 0.490 (Przewalskii horse) to 0.761 (Mongolian horse) with an average value of 0.637 in horse breeds. The results showed three distinct clusters with high bootstrap support: the Korean native horse cluster (Korean native horse, Mongolian horse), the European cluster (Przewalskii horse, Thoroughbred horse), and other horse cluster (Jeju racing horse, Japan Hokkaido horse, and Quarter horse). A relatively high bootstrap value was observed for the Korean native horse cluster and European cluster (87%), and the Korean native horse and Mongolian horse (82%). Microsatellite polymorphism data were shown to be useful for estimating the genetic relationship between Korean native horse and other horse breeds, and also be applied for parentage testing in those horse breeds.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.571-571
• /
• 2012

We discovered the formation of C60 aggregates in solution by means of photoluminescence spectroscopic study on C60 in solutions. From the in-depth investigation of temperature dependence of the luminescence of C60 in toluene, benzene and CS2 solutions, we reported that the C60 aggregates are formed during cooling at the freezing temperature of these solvents. Furthermore, the C60 aggregates can be changed to stable structures by irradiating with UV pulse-laser (Nd:YAG laser, 355nm). As a consequence, we could obtain nano-scale photo-polymerized C60 clusters, which appear as round-shaped nano- scale particles in high resolution transmission electron-microscopy (HRTEM) images. However, the yield of the nano-scale C60 clusters obtained by this method is too small. So we designed and developed a system to obtain C60 cluster of macroscopic quantity by using ultrasonic nebulizer. In this system, C60 solution was vaporized to several micro-sized droplets in vacuum, resulting in the formation of C60 aggregates by evaporating solvent (toluene). The system was invented to produce nano-scale carbon clusters by the irradiation of UV light upon C60 aggregates in vacuum. We have characterized the products, C60 cluster, obtained from the system by using UV absorption spectra and HPLC spectra. Although the products have a possibility of inclusion various forms of C60 cluster, results support that the product formed from the system by using vaporizer method establishes a new method to obtain C60 cluster in macroscopic quantity. In the presentation, the details of the system and the results of characterization are reported.

• Journal of the East Asian Society of Dietary Life
• /
• v.24 no.6
• /
• pp.915-923
• /
• 2014

This study investigated organic coffee choice motives from a coffee shop market segmentation perspective in order to understand the potential importance they may have upon attitudes and behavioral intentions to buy organic coffee. A factor-cluster segmentation approach was used for this study. An exploratory factor analysis identified five organic coffee choice motives: 'Sensory', 'Environment', 'Trust', 'Health' and 'Price'. Based upon these five choice motives, cluster analyses classified all respondents into three homogeneous subgroups: 'Highly motivated', 'Moderately motivated' and 'Unmotivated'. Analysis of variance tests indicated that attitudes and intentions to purchase organic coffee were significantly different among the three clusters. In particular, two cluster groups representing 'Highly motivated' and 'Moderately motivated' were found to offer the most utility for further organic coffee market segmentation research. Especially, due to perceptions about high price premium of organic coffee, the 'Moderately motivated' group had higher positive attitudes, although, their intentions to buy organic coffee were not higher than those of the 'Unmotivated' cluster. Findings support previous research propositions that high price could be the strongest barrier for people to purchase organic products including the organic coffee business context. This will assist to market and promote pricing strategies for caf$\acute{e}$s and restaurants to optimize organic coffee sales revenue. Implications for all cluster groups regarding unique socio-demographic characteristics and behavioral intentions are discussed. Organic coffee marketers can apply these findings towards the development of effective target market strategies.

• Journal of KIISE:Computer Systems and Theory
• /
• v.29 no.10
• /
• pp.550-560
• /
• 2002

External sort on cluster computers requires not only fast internal sorting computation but also careful scheduling of disk input and output and interprocessor communication through networks. This is because the overall time for the execution is determined by reflecting the times for all the jobs involved, and the portion for interprocessor communication and disk I/O operations is significant. In this paper, we improve the sorting performance (sorting throughput) on a cluster of PCs with a low-speed network by developing a new algorithm that enables even distribution of load among processors, and optimizes the disk read and write operations with other computation/communication activities during the sort. Experimental results support the effectiveness of the algorithm. We observe the algorithm reduces the sort time by 45% compared to the previous NOW-sort[1], and provides more scalability in the expansion of the computing nodes of the cluster as well.