• The KIPS Transactions:PartA
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• v.14A no.7
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• pp.443-450
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• 2007

Performance scalability and storage scalability become important in a large scale cluster of wireless internet proxy cache servers. Performance scalability means that the whole performance of the cluster increases linearly according as servers are added. Storage scalability means that the total size of cache storage in the cluster is constant, regardless of the number of cache servers used, if the whole cache data are partitioned and each partition is stored in each server, respectively. The Round-Robin based load balancing method generally used in a large scale server cluster shows the performance scalability but no storage scalability because all the requested URL data need to be stored in each server. The hashing based load balancing method shows storage scalability because all the requested URL data are partitioned and each partition is stored in each server, respectively. but, it shows no performance scalability in case of uneven pattern of client requests or Hot-Spot. In this paper, we propose a novel dynamic hashing method with performance and storage scalability. In a time interval, the proposed scheme keeps to find some of requested URLs allocated to overloaded servers and dynamically reallocate them to other less-loaded servers. We performed experiments using 16 PCs and experimental results show that the proposed method has the performance and storage scalability as different from the existing hashing method.

• Journal of the Korean Association of Geographic Information Studies
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• v.19 no.1
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• pp.12-29
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• 2016

The purpose of this study was to improve forestland characteristic evaluation system's indicators for rational development and ecosystem conservation. There has been no consideration for statistical duplication between variables, and it caused inefficient data collection. Furthermore, the same evaluation criteria were applied for all forestlands without considering regionally different characteristics, and it made variation for designation cancel rates of preservation semi-preservation forestlands between cities. To solve these problems, we first removed 'DBH' variable which has a multicollinearity. Second, we applied standard normal distribution for each forest watershed type. As a result of eliminating 'DBH', the numbers of parcels for all grades except A were changed but their numbers and areas were not large enough to consider the change of total score. For the output of analyses with the existing same regional criteria, the total scores of urban type and urban-fringe type forestlands were higher than those of other types. The numbers of parcels for A and B were increased and those for C and E were decreased by applying standard normal distribution. This caused the increase of preservation-oriented parcels. Finally, we suggested a new evaluation method based on standard normal distribution to consider regional forest characteristics and to solve regional imbalance.

• Korean Journal of Social Welfare
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• v.69 no.1
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• pp.223-254
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• 2017

This study was carried out to examine whether the moderated mediating effect of SNS addiction resulting from marital dissatisfaction and loneliness is influenced by gender or size and composition of social capital. 714 married men and women in their 20's to 40's were participated in this study. The data were collected by online research center with quota sampling based on demographical proportion. To analyze this research model, the moderated mediating effect utilizing structural equation was used. The results of this study were summarized as follows. First, it is verified that the loneliness moderated between marital dissatisfaction and SNS addiction. Since the relationship between independent and dependent variable is insignificant, comparison of competition model was able to determine if mediating effect was fully or partially shown. As a result, the complete mediated model was ultimately chosen because its various goodness-of-fit index including $x^2$ performed fairly well. Second, the mediating effect which moderates social capital size was presented in the mediated model between the marital dissatisfaction, loneliness and SNS addiction. Specifically, It implies that group who recognizes their social capital big recognizes the route and effect size more than that who considers their social capital small. And the moderated mediating effect depending on different type of social capital among the marital dissatisfaction and loneliness and between SNS addiction was substantiated. It implies that disequilibration of SNS social capital in face-to-face sphere and in online acted as a danger fact with respect to the marital dissatisfaction, loneliness and SNS addiction. The implications of these findings were discussed, and directions for future studies were also proposed.

• Journal of the Korean Chemical Society
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• v.53 no.6
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• pp.653-662
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• 2009

Developing effective tools for predicting absorption, distribution, metabolism, excretion properties and toxicity (ADME/T) of new chemical entities in the early stage of drug design is one of the most important tasks in drug discovery and development today. As one of these attempts, support vector machines (SVM) has recently been exploited for the prediction of ADME/T related properties. However, two problems in SVM modeling, i.e. feature selection and parameters setting, are still far from solved. The two problems have been shown to be crucial to the efficiency and accuracy of SVM classification. In particular, the feature selection and optimal SVM parameters setting influence each other, which indicates that they should be dealt with simultaneously. In this account, we present an integrated practical solution, in which genetic-based algorithm (GA) is used for feature selection and grid search (GS) method for parameters optimization. hERG ion-channel inhibitor classification models of ADME/T related properties has been built for assessing and testing the proposed GA-GS-SVM. We generated 6 different models that are 3 different single models and 3 different ensemble models using training set - 1891 compounds and validated with external test set - 175 compounds. We compared single model with ensemble model to solve data imbalance problems. It was able to improve accuracy of prediction to use ensemble model.

• Korean Journal of Poultry Science
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• v.51 no.2
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• pp.73-82
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• 2024

The gut microbiome of broilers is a critical factor in overall health and productivity. However, high summer temperatures and high stocking density (conventional farm condition) may cause stress to broilers, resulting in an imbalance in the gut microbiome. This study was conducted to compare the gut microbiome of broilers between spring and summer in welfare (Bosung, Jeollanam-do, South Korea) and conventional farms (Jangsu, Jeollabuk-do, South Korea). A total of 31 broilers were assigned to the following groups: conventional farm in spring (n = 8); conventional farm in summer (n = 8); welfare farm in spring (n = 7); welfare farm in summer (n = 8). Cecal digesta were collected from eight broilers from each farm, and microbiome analysis was performed using 16S rRNA gene sequencing. Beta diversity analysis indicated clear differences in cecal microbiome composition between spring and summerin both welfare and conventional farm. At the phylum level, analysis of conventional farm revealed a higher proportion of Bacteroidetes in spring than in summer. At the genus level, broilers exhibited a higher abundance of Bacteroides and Alistipesin spring compared to summer. In contrast, the difference in microbial flora composition observed in welfare farm was relatively small compared to conventional farm. In conclusion, the results of this study suggest that heat stress can negatively affect the caecum microbiome of broilers. However, improvements in the housing environment can mitigate the effects of heat stress.