• Journal of Wetlands Research
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• v.13 no.3
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• pp.581-591
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• 2011

To reveal the relationship between pond type and chemical water characteristics and wetland flora, we investigated 8 small irrigation ponds in CCZ, which represent 4 types of irrigation ponds. Cation and anion concentrations in water were low at spring type ponds and cation or anion concentrations were high at others. Especially, Kyeongeuisun pond, which is water exchanging type, had high cation and anion concentrations. This indicates that water source of this ponds is surface water. CCA showed that chemical water characteristics and wetland flora were reflected in pond types. However, water exchanging type ponds were not clustered in a group, which comes from the difference in water source and we suggest that water source should be an additional criteria to devide pond type of water exchanging.

• Journal of Intelligence and Information Systems
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• v.13 no.1
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• pp.81-90
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• 2007

This paper shows an intelligent disease diagnosis system for public. Our system deals with 30 diseases and their typical symptoms selected based on the report from Ministry of Health and Welfare, Korea. Technically, the system uses a modified FCM algorithm for clustering diseases and the input vector consists of the result of user-selected questionnaires. The modified FCM algorithm improves the quality of clusters by applying symmetrically measure based on the fuzzy theory so that the clusters are relatively sensitive to the shape of the pattern distribution. Furthermore, we extract the highest 5 diseases only related to the user-selected questionnaires based on the fuzzy membership function between questionnaires and diseases in order to avoid diagnosing unrelated disease.

• The Korean Journal of Cytopathology
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• v.4 no.1
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• pp.74-76
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• 1993

Cytologic findings of pleural effusion in three cases of rhabdomyosarcoma are reported. Case 1 was a pleomorphic rhabdomyosarcoma which had devoped at the chest wall of an elderly male patient and caused pleural effusion. The cytologic features were consistent with pleomorphic rhabdomyosarcoma, that was, showing loose clusters, cellular pleomorphism, and abundant finely vesicular cytoplasm. Cases 2 and 3 were embryonal rhabdomyosarcomas in young adults. Primary site was the oral cavity in case 1, but unknown in case 2 and case 3. The effusion cytology was similar in these cases. Clustered or isolated small round cells with hyperchromatic nuclei and scanty cytoplasm were smeared. The cohesiveness of tumor cells was weak and the cells did not show linear arrangement or nuclear melding. Effusion cytology in a sarcoma patient would be diagnostic when the primary site and the type of sarcoma were already known.

• The Korean Journal of Applied Statistics
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• v.31 no.6
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• pp.721-732
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• 2018

Latent class analysis (LCA) is an important tool to explore unseen latent groups in multivariate categorical data. In practice, it is important to select a suitable set of variables because the inclusion of too many variables in the model makes the model complicated and reduces the accuracy of the parameter estimates. Dean and Raftery (Annals of the Institute of Statistical Mathematics, 62, 11-35, 2010) proposed a headlong search algorithm based on Bayesian information criteria values to choose meaningful variables for LCA. In this paper, we propose a new variable selection procedure for LCA by utilizing posterior probabilities obtained from each fitted model. We propose a new statistic to measure the adequacy of LCA and develop a variable selection procedure. The effectiveness of the proposed method is also presented through some numerical studies.

• Korea Trade Review
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• v.43 no.4
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• pp.177-217
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• 2018

The purpose of this study is to classify the types of internationalization strategies utilized by Korean ventures and to examine whether there is a significant relationship between these types and internationalization performances. Specifically we tested whether there is a good feasibility through empirical analysis of the study model constructed through the following process. As a criterion of typification, the capability of international entrepreneurship and the capability of effectuation of a venture were chosen, and a model in which those three types exist based on the capabilities is established. The characteristics of each type and the contents of internationalization strategy are explained and empirical analysis is conducted. We also test whether there are significant differences in internationalization performance for each type. As a result of the cluster analysis, we concluded that there are three types : pioneer, careful preparation and passive response. In addition, these three types have significant differences in the levels of performances of reputation in foreign markets and the accumulation of knowledge in international management. This implies significant differences among the performances of each type of ventures according to their internationalization strategy positions. Therefore, the type of venture should be considered when a venture establishes its internationalization strategy and governments set supporting policy for venture companies.

• Korean Journal of Environment and Ecology
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• v.28 no.3
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• pp.302-313
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• 2014

This study was conducted to compare the characteristics of fish distribution according to sand type stream and cobble type stream the 4 stream selected every season. The collected Korea endemic species during the survey period were 24, including Acheilognathus gracilis. Dominant species of Hongcheon stream and Muju Namdae stream was Zacco koreanus, each accounting for 39.9% and 28.4% in order, and dominant species in Yanghwa stream was Rhodeus notatus, 13.6%, and those in Gap stream was Z. platypus, by 26.0%. As a result of community analysis, dominant index was 0.27~0.63, diversity index was 1.92~2.67, evenness index was 0.6~0.79, richness index was 3.09~3.53, and dominant index was the highest in Hongcheon stream, and the indices of diversity, evenness and richness were the highest in Yanghwa stream. As a result of tolerance guild analysis, Hongcheon stream and Muju Namdae stream with a variety of substrates accounted for relatively higher rate by 50.1% and 46.4% in sensitive species respectively, and Yanghwa stream and Gap stream with greater sand substrates had 0.5% and 5.3% scarce rate of sensitive species. As a result of similarity analysis using the species, population and substrate structures of the fisheries appeared in each stream, cobble type streams such as Hongcheon stream and Muju Namdae stream were the most similar by 50.4% in species and population, 95.2% in bed structure. As a result of IBI analysis, Hongcheon stream and Muju Namdae stream appeared as 'Class A,' Yanhwa stream and Gap stream as 'Class B' and the two groups of cobble type stream and sand type stream were divided as a result of principal components analysis.

• Journal of Korean Society of Forest Science
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• v.102 no.3
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• pp.407-414
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• 2013

This study was conducted to classify forest cover types using the multivariate statistical analysis in the natural forest of western Mt. Jiri. On the basis of the vegetation data by point quarter sampling, the adopted analytical methods were species-area curve (SAC), hierarchical cluster analysis (HCA), indicator species analysis (ISA), and multiple discriminant analysis (MDA). SAC selected the outlier tree species which was likely to have no influence on the classification of forest cover types, excluded from all analytical process. Based on forest vegetative information, HCA classified the study area into 2 to 10 clusters and ISA indicated that the optimal number of clusters were seven. MDA was taken to test the clusters that classified with HCA and ISA. The seven clusters were classified appropriately as overall classification success were 91.3%. The classified forest cover types were named by the ratio of the dominant species in the upper layer of each cluster. They were (1) Quercus mongolica Pure forest, (2) Mixed mesophytic forest, (3) Q. mongolica - Q. serrata forest, (4) Abies koreana - Q. mongolica forest, (5) Fraxinus mandshurica forest, (6) Q. serrata forest, and (7) Carpinus laxiflora forest.

• Korean Journal of Environment and Ecology
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• v.23 no.5
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• pp.381-391
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• 2009

This is the study of the effects and changes on the ichthyofauna and fish community in Jeonju-cheon stream (located in Jeonju Cit, Jeollabuk-do, South Korea) after the implementation of the Natural Stream Restoration Project. The restoration of the stream was carried out between April 2000 and December 2002, and it covered the mid-section of the stream starting from the upstream of Hanbyeok Bridge down to Samcheon where branches of water join. It is 7.2 km long and passes through the downtown area. In this study, comparisons were made before and after the restoration. Before the restoration (1975 to 1999), the number of fish species collected from the Jeonju-cheon stream turned out to be 12 to 18 species, whereas after the restoration (2003 to 2008), it increased up to 34 species in total. Especially in the case of the middle and downstream sections running across the central regions of the city (Daga Bridge to Seosin Bridge), the number of fish species significantly increased from 5 species to 22 species. Such a dramatic increase of fish species appears to be directly related to the restoration of the stream which was designed to improve the quality of water by preventing polluted sewage water from running into the stream. Besides, the structure of stream bed which became more diversified into various components such as marshes and shallows, as well as rocks, Pebbles, sand and clay, also contributed to the increase of fish species.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.04a
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• pp.407-409
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• 2017

지능형 튜터링 시스템(Intelligent Tutoring System, ITS)은 학습자에게 자동으로 학습코스를 제공하는 시스템으로, 현재 비전공자 대상 코딩 교육용 ITS 수요가 증가하고 있음에 따라 본 연구팀도 비전공자 대상 코딩 교육용 ITS "Everycoding"을 개발하였다. 더 나아가 학습자 별 맞춤형 코딩 교육 튜터링 시스템 개발 요구가 늘어나고 있다. 이에, 본 연구에서는 기계학습 기법을 적용하여 개발한 협업 능력 기반의 학습자 모델을 군집 분석하고, 그에 따른 학습자 별 맞춤 피드백을 제공하는 기준을 제안한다.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.8
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• pp.399-410
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• 2005

This paper Proposes a novel adaptive genetic algorithm (GA) extrapolated by an ant colony optimization. We first prove that the algorithm converges to the unique global optimal solution with probability arbitrarily close to one and then, by experimental studies, show that the algorithm converges faster to the optimal solution than GA with elitism and the population average fitness value also converges to the optimal fitness value. We further discuss controlling the tradeoff of exploration and exploitation by a parameter associated with the proposed algorithm.