• The Korean Journal of Ecology
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• v.28 no.6
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• pp.405-415
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• 2005

This paper considers the advantage of Machine Learning (ML) implemented to freshwater ecosystem research. Currently, many studies have been carried out to find the patterns of environmental impact on dynamics of communities in aquatic ecosystems. Ecological models popularly adapted by many researchers have been a means of information processing in dealing with dynamics in various ecosystems. The up-to-date trend in ecological modelling partially turns to the application of ML to explain specific ecological events in complex ecosystems and to overcome the necessity of complicated data manipulation. This paper briefly introduces ML techniques applied to freshwater ecosystems in Korea. The manuscript provides promising information for the ecologists who utilize ML for elucidating complex ecological patterns and undertaking modelling of spatial and temporal dynamics of communities.

• Journal of Multimedia Information System
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• v.8 no.3
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• pp.183-190
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• 2021

In this paper, we implement a system for a fund recommendation based on the investment propensity and for a future fund price prediction. The investment propensity is classified by scoring user responses to series of questions. The proposed system recommends the funds with a suitable risk rating to the investment propensity of the user. The future fund prices are predicted by Prophet model which is one of the machine learning methods for time series data prediction. Prophet model predicts future fund prices by learning the parameters related to trend changes. The prediction by Prophet model is simple and fast because the temporal dependency for predicting the time-series data can be removed. We implement web pages for the fund recommendation and for the future fund price prediction.

• Journal of Korea Multimedia Society
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• v.22 no.8
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• pp.897-912
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• 2019

The growth of domestic fashion industry market went sluggish affected by long-term slow growth and shrinking consumer sentiment since 2012, and the entire market has shown a slight growth since 2017. Yet only some conglomerates or global businesses experience this growth. Small and medium-sized fashion companies or rising fashion designers in South Korea, face real limitations and problems poor capital, lack of professional workforce, experience, information and educational opportunity as well as difficulty of acquiring distribution network, which lead to further polarization between conglomerates and small businesses. Thus, this study proposed mobile virtual viewer system-based collaborative application prototype capable of overcoming limitations and problems drawn by analyzing business environment of domestic brands launched by rising fashion designers. Especially, through applied template-based 3D virtual fashion design technology and performing the entire process in the virtual reality beyond spatial and temporal restraints, it is assumed that more effective and efficient outcomes can be obtained compared to the previous method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.3B
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• pp.380-389
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• 2010

Since the internet is intend to be the best effort service, the system that stream a large amount of high quality medias need a techniques to overcome the network status for implementation. In this paper, we design and implement a method that estimate quickly whether network permits the needed bandwidth of media and a method that control QoS through that. Presented system uses Relative One-Way Delay(ROWD) trend in the case of the former, and leverages temporal encoding among Scalable Video Coding(SVC) that is apt to apply real time comparatively in the case of the latter. The streaming server classifies the medias by real time to several rates and begins transmission from top-level and is reported ROWD trend periodically from the client. In case of the server reported only 'Increase Trend', the sever decides that the current media exceeds the available bandwidth and downgrades the next media level. The system uses probe packet of difference quantity of the target level and the present level for upgrading the media level. In case of the server reported only 'No Increase Trend' by the ROWD trend response of the probe packet from client, the media level is upgraded. The experiment result in a fiber to the home(FTTH) environment shows progress that proposed system adapts faster in change of available bandwidth and shows that quality of service also improves.

• Journal of Korea Water Resources Association
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• v.43 no.4
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• pp.409-419
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• 2010

In this study, for the purpose of analyzing the characteristics of Korean hydrologic weather parameters, 9 hydrologic weather parameters data such as annual precipitation, annual rainy days, annual average relative humidity, annual average temperature, annual duration of sunshine, annual evaporation, annual duration of precipitation, annual snowy days and annual new snowy days are collected from 63 domestic meteorological stations that has the hydrologic weather parameters records more than 30 years. And the basic characteristics of hydrologic weather parameters through basic statistics, moving average and linear regression analysis are perceived. Also trend using the statistical methods like Hotelling-Pabst test and Mann-Kendall test about hydrologic weather parameters is analyzed. Through results of basic analysis, moving average and linear regression analysis it is shown that precipitation is concentrated in summer and deviation of precipitation for each season showed significant difference in accordance with Korean climate characteristics, besides the increase in annual precipitation and annual average temperature, annual average relative humidity and annual duration of sunshine reduction and annual rainy days is said to increase or decrease. The results of statistical analysis of trend are summarized as trend commonly appeared in annual average relative humidity and annual average temperature. and annual precipitation, annual rainy days and annual duration of sunshine showed different results according to area.

• Korean Journal of Agricultural and Forest Meteorology
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• v.24 no.2
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• pp.83-94
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• 2022

In order to actively prepare to frost damage that occurs in the process of growing crops, the spatial and temporal distribution of frost occurrence in South Korea was derived using frost observation data from 20 regions over the past 21 years (2000~2020). The main products are the number of frost days, first frost day, and last frost day by region. And the climatic trends of these results were identified by performing the Mann-Kendall trend test and Sen's slope estimator. In South Korea, a lot of frost occurs in the inland area to the west of the Taebaek and Sobaek Mountains. Relatively closer to the coastal area, the number of frost days is small, the first frost day is slow, and the last frost day is early. The east coast region has fewer frost days, the first frost day is later, and the last frost day is earlier than the west coast region. The southern sea, the southeastern sea region, and the island region rarely experience frost. As a result of the annual time series trend analysis, although South Korea is a country where climate warming is progressing, there was no trend in reducing the number of frost days and slowing the first frost day, and it was found that the last frost day is delayed by 0.5 days per year.

• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.4
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• pp.204-214
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• 2006

The necessity of a management for a metropolitan has long intrigued many urban scholars and researchers who are interested in Busan metropolitan spatial structure and its problems. The purpose of this study is to investigate the dynamic changes of spatial structure in Busan Metropolitan by analyzing the population, employment and Land prices, for the period of 1993, 2001. The major results in this study are as follows; While main-centers have experienced significant loss of population, sub-centers have been growing. Jung-Ang Dong still has high accessibility in population potentials, but its accessibility has declined since 1993. Pu-Jeon Dong had increasing trend of population until 2000, but its population has also descended since that time. Meanwhile, the population of sub-centers has increased in its accessibility. And The spatial pattern of the population in Busan has changed from monocentric to polycentric. This phenomenon was almost spontaneously generated from population dispersion from existing main-centers. In terms of change of land values are there is a spatial and temporal rhythm in the urbanization of Busan. The highest land value in Busan is shown in CBD. The development of Busan proceeded along the north-south belt and extended to west Busan.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.4
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• pp.339-344
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• 2009

The joint cruises of six times between Korea and China were carried out for a better understanding of the environmental and oceanographical characteristics of the Yellow Sea for 6 years from 1998 to 2003. Zooplankton samples were collected one time per year at 24 stations on 3 lines of the Yellow Sea. The aim of this study is to understand the seasonal fluctuation of zooplankton community in the Yellow Sea. There is no trend on the spatio-temporal distribution of zooplankton. Copepoda, the major taxon of the Yellow Sea, was high in distribution in the eastern part and Chaetognatha in the western part of the Yellow Sea. In this results, the dominant copepods were Calanus sinicus, Paracalanus parvus s.l., Oithona atlantica, and Corycaeus affinis during the study periods. The density fluctuation of these dominant species may be an important factor in determining the fisheries resource of the Yellow Sea.

• Journal of Families and Better Life
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• v.34 no.3
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• pp.65-84
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• 2016

This study examined the factors that were associated with longitudinal changes for ten years from 2004 to 2014 in time spent on housework by married couples who had a preschooler as their first-born child. It also sought to figure out how much of such temporal changes were attributable to differences in the means on associated factors as well as to differences in the influence or slope of such factors. A total of 9,668 time diaries from the Korean Time Use Survey were used to analyze the influence of couple's weekly work hours, wife's relative income, couple's education and gender role attitudes on the time spent on housework of husbands and wives. Results from descriptive statistics, regression and decomposition analysis were as follows. First, women decreased, while men increased their time doing housework. Second, weekly work hours of husband and wife were related to their time doing housework in every year surveyed. Third, wife's relative earnings and couple's gender role attitudes affected wife's time doing housework more than husbands', whereas couple's education had stronger effects on husbands than wives. However, such influence was apparent on a certain survey year, and then disappeared in another, or became stronger or weaker longitudinally. Fourth, the temporal decrease in wife's housework time and increase in husband's housework time were attributable to social and cultural changes such as reduced working hours, rising female income, higher educational background, and prevalence of egalitarian gender role attitudes. Findings suggest that the trend in spending time on housework is expected to continue, and provide a timely policy implications to facilitate the change.

• Journal of Environmental Impact Assessment
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• v.15 no.5
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• pp.323-337
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• 2006

This work discussed the species composition, phylogeny, spatio-temporal distribution, ecology and natural history of North Korean Pinaceae or pine tree family, which seems to be important to maintain nature and ecosystem in the Korean Peninsula. Out of five genera and sixteen species of Pinaceae of the Korean Peninsula, North Korea contains four genera and eleven species of Pinaceae, including Pinus densilflora, P. koraiensis, P. pumila, Picea jezoensis, P. koraiensis, P. koraiensis var. koraiensis, P. pungsanensis, Larix gmelini, L. gmelinii var. olgensis, Abies holophylla and A. nephrolepis. In terms of phylogeny Pinus is closely related to Picea, and followed by Larix. Abies is close to Tsuga which only occur at Ullung Island. Distributional pattern of North Korean Pinaceae can be classified into four types; three species of nation-wide montane type i.e., Pinus densilflora, P. koraiensis and Abies holophylla, four species of central and northern subalpine type, i.e., Pinus pumila, Picea koraiensis, Larix gmelini and Abies nephrolepis, one nation-wide subalpine type, Picea jezoensis, and three species disjunctive to north type, i.e., Picea koraiensis var. koraiensis, P. pungsanensis, and Larix gmelinii var. olgensis. Pinaceae species occurring on the alpine and subalpine belts of North Korea, such as Pinus koraiensis, P. pumila, Picea jezoensis, P. koraiensis, P. koraiensis var. koraiensis, P. pungsanensis, Larix gmelini, L. gmelinii var. olgensis and A. nephrolepis are considered as the glacial descendant from the boreal region. Those species might have migrated from the north during the Pleistocene glacial epochs in search of favourable condition, and since the Holocene period they survived on the hostile alpine and subalpine environments, in which they are more competitive than warmth-tolerant temperate vegetation. Certain species, such as Picea pungsanensis, is segregated on the isolated mountains since the Pleistocene period, and forced to adapt to local environment, and eventually became an endemic species of North Korea. Recent rapid global warming trend especially in northern high mountains of North Korea could cause an unfavourable environment for the survival of cold-tolerant Pinaceae of the alpine and subalpine belts. Pinus densiflora, which is occurring on the montane belt might faced with difficulties due to both the deforestation and the outbreak of insect-borne disease, such as Bursaphelenchus xylophilus.