• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2007.11a
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• pp.75-75
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• 2007

• Journal of the Korean Data and Information Science Society
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• v.21 no.5
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• pp.863-871
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• 2010

Until now, many studies related circular data are carried out, but the focuses are mainly on mildly peaked symmetric or asymmetric cases. In this paper we studied a modeling process for sharply peaked asymmetric circular data. By using wrapped Laplace, which was firstly introduced by Jammalamadaka and Kozbowski (2003), and its mixture distributions, we considered the model fitting problem of multi-modal circular data as well as unimodal one. In particular we suggested EM algorithm to find ML estimates of the mixture of wrapped Laplace distributions. Simulation results showed that the suggested EM algorithm is very accurate and useful.

• Journal of the Korean Data and Information Science Society
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• v.21 no.2
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• pp.241-250
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• 2010

Over the past few decades, several studies have been made on the modeling of circular data. But these studies focused mainly on the symmetrical cases including von Mises distribution. Recently, many studies with skew-normal distribution have been conducted in the linear case. In this paper, we dealt the problem of fitting of non-symmetrical circular data with wrapped skew-normal distribution which can be derived by using the principle of wrapping. Wrapped skew-normal distribution is very flexible to asymmetical data as well as to symmetrical data. Multi-modal data are also fitted by using the mixture of wrapped skew-normal distributions. To estimate the parameters of mixture, we suggested the EM algorithm. Finally we verified the accuracy of the suggested algorithm through simulation studies. Application with real data is also considered.

• Journal of Korean Society of Forest Science
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• v.103 no.4
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• pp.687-695
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• 2014

The purpose of this study is to identify landscape paintings of our ancestors in types and characteristics of beautiful natural scenery. In this study, 629 landscape paintings targeted natural scenery of the Joseon Dynasty period are used and classified into types of natural scenery by main target of paintings. As the results of this study, landscape paintings are classified into mountain, river, sea, city by place drawing painting. The paintings drawn in mountain are classified into a few mountain peaks, many mountain peaks, one mountain peak, curious rock of mountain, valley and waterfall. The paintings drawn in river are classified into river and mountain, river water, scenery of riverside and curious rock of river. The paintings drawn in sea are classified into scenery of seaside and curious rock of sea. And the paintings drawn in city are classified into panoramic view of the town. The type of natural scenery in landscape paintings can be summarized in 3, scenery of mountain peaks, scenery of curious rock peaks and waterspace when combine place drawing painting.