• Journal of Plant Biology
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• v.28 no.2
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• pp.149-164
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• 1985

Intertidal algal community of Muchangpo in western coast of Korea was investigated qualitatively and quantitatively. Seasonal changes of algal occurrence, dominant species in cover, vertical zonation pattern and biomass were analysed. A total of sixty-four species of marine algae, one blue-green alga, three green algae, nineteen brown algae and forty-one red algae, were identified. The dominant species in cover were Sargassum thunbergii, Gelidium divaricatum and Pelvetia siliquosa throughout the year. Gloiopeltis furcata was abundant at upper and middle littoral zones and Corallina pilulifera at lower littoral zone. Classification by unweighted pair-group average method and ordination by reciprocal averaging based on the cover data indicated that, on the whole, the intertidal algal vegetation showed different patterns along tidal levels. Seasonal fluctuations of mean biomass were 57.2~92.8 g-dry/$m^2$, and the highest in summer and the lowest in spring season. Seasonal change of community structure was also discussed.

• Korean Journal of Environment and Ecology
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• v.5 no.1
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• pp.32-41
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• 1991

A survey of subalpine zone (altitude is 1,360-1,410m) in Mt. Chiri, was conducted using 25 sample plots of 500$m^2$ size. The classification by TWINSPAN and DCA ordination were applied to the study area in order to classify them into several groups based on woody plants and environmental variables. By TWINSPAN techniques, the plant community were divided into five groups by importance value of Abies nephrolepis. The dividing groups are Fraxinus rhynchophylla - Magnolia sieboldii community, Quercus mongolica - Rhododendron schlippenbachii community, Q. mongolica - F. rhynchophylla - Acer pseudo-sieboldianum community, Q. mongolica- A. nephrolepis- Rh. schlippenbachii community, and A. nephrolepis- Pinus densiflora - Rh. schlippenbachii community. The successional trends of tree species by both techniques seem to be from Q. mongolica to A. nephrolepis in the canopy layer. It was no difference between the stand scores of DCA and environmental variables.

• KIPS Transactions on Software and Data Engineering
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• v.10 no.5
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• pp.169-178
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• 2021

Recently, a bike-sharing system (BSS) has become popular as a convenient "last mile" transportation. Rebalancing of bikes is a critical issue to manage BSS because the rents and returns of bikes are not balanced by stations and periods. For efficient and effective rebalancing, accurate traffic prediction is important. Recently, cluster-based traffic prediction has been utilized to enhance the accuracy of prediction at the station-level and the clustering step is very important in this approach. In this paper, we propose a k-means based clustering algorithm that overcomes the drawbacks of the existing clustering methods for BSS; indeterministic and hardly converged. By employing the centroid initialization and using the temporal proportion of the rents and returns of stations as an input for clustering, the proposed algorithm can be deterministic and fast.

• Journal of the Mineralogical Society of Korea
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• v.13 no.4
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• pp.205-220
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• 2000

북동태평양 C-C지역의 우리나라 광구에서 산출되는 망간단괴의 내부조직을 크게 주상조직 층상대, 첨상조직 층상대, 첨상조직 괴상대, 첨상조직 다공질대 및 괴상조직 괴상대로 구분하였다. 주상조직 층상대에서는 버나다이트(vernadite)가 가장 우세하게 산출되며, 첨상조직 층상대에서는 부서라이크(buserite)가 함께 산출된다. 첨상조직 괴상대는 부서라이트의 산출이 두드러지며, 부분적으로 토도로카이트(todorokite)가 수반된다. 첨상조직 다공질대는 첨상체 또는 구상체로 이루어지며 부분적으로 괴상조직으로 교대되는데 주로 토도로카이트와 부서라이트로 구성되어 있다. 괴상조직을 갖는 괴상대에서는 토도로카이트와 버네사이트(birnessite)가 부서라이트와 함께 산출된다. 각 조직대별로 미세조직을 이루는 엽리들에 대해 전자현미분석을 실시하였다. 엽리의 화학조성을 구성하는 요인은 상관계수 군집분석에 의해 Mn-K의 Mn군, Cu-Ni-Zn-Mg(Ca-Na)의 Cu-Ni-Mg군 Fe-Co-Ti(Ca-P)의 Fe군과 Si-Al의 Si군 등 네 개군으로 구분된다. 각 조직대는 세 개 또는 네 개의 군으로 구성되며 이들 각군은 단괴에서 산출되는 광물과 밀접한 관계를 가진다. Mn군은 토도로카이트, Cu-Ni-Mg군은 부서라이트, Fe군은 함코발트수산화철광물, 그리고 Si군은 규산염광물에서 주로 기인하는 것으로 생각된다. 엽리의 화학조성은 이들 광물의 조합과 구성광물의 화학조성에 따라 지배되고 한 조직대내에서도 여러종류의 조합을 보이는데 이는 각 조직대의 엽리들의 성인과 밀접한 관련이 있는 것으로 생각된다.

• Korean Journal of Environment and Ecology
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• v.11 no.4
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• pp.450-461
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• 1998

To investigate the plant community structure of Paekdam-Valley in Soraksan National Park, fifty-two plots have been set up and surveyed. By DCA ordination technique, the plant communities were classified into fkve community types, which were Pinus densiflora community and Q. mongolica community. It was supposed that Q. serrata community change to C. laxiflora community. It seemed that P. densiflora community, deciduous broad-leaved mixed forest and Q. serrata community would not be replace by another woody species. And it seemed that C. laxiflora community succeeded to Q. serrata community, so it was similar to the typical ecological succession of natural forest in the middle temperate regions. The range of Shannon's diversity index was 0.9827~1.2946(Unit area : 400m$^2$) and that was over another Korean National Parks area relatively.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.05a
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• pp.452-454
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• 2001

우리나라 서해안에 위치한 함평만은 만 입구의 폭이 만 내의 폭에 비해 상당히 좁아 1.8km정도 밖에 안 되는 반폐쇄적인 만이다. 또한, 창조류보다 낙조류가 우세하고 외해의 영향을 많이 받지 않는 독특한 환경으로서 침식작용보다는 퇴적작용이 우세한 곳이다. 본 연구에서는 함평만 펄 조간대에 서식하는 저서동물의 군집 구조를 파악하고 주요 우점종들의 공간분포 양상을 파악하고자 하였다. (중략)

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.1
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• pp.83-88
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• 2013

This paper proposes a recommending system of the similar blogs gathered with similarities between blogs according to the similarity, dividing words, for each frequency, that individual blogs have. It improved the algorithm of k-means, using the model of the habits of white ants for better performance of clustering, and showed better performance of clustering as a result of evaluating and comparing with the existing algorithm of k-means as the improved algorithm. The recommending system of similar blog was designed and embodied, using the improved algorithm. TCA can reduce clustering time and the number of moving time for clustering compare with K-means algorithm.

• Korean Journal of Environment and Ecology
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• v.5 no.1
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• pp.9-24
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• 1991

To elucidate the actual vegetation of Nature Ecology Conservation area in Mt. Chiri, forest communities were classified phytosoclologically by species composition and phsiognomy. There included 13 forests ranging from temperate-cool zone to sub-cold zone in the surveyed area. Actual vegetation map was drawn on the basis of classified forest communities. The forest communities classified in the area were summarized as follows ; 1. Querus serrata community 2. Carpinus laxiflora community 3. Q. serrata-C. laxiflora community 4. Stewartia koreana community 5. Acer mono community 6. Carpinus cordata community 7. Fraxinus mandshurica community 8. Carpinus tschonoskii community 9. Pinus densiflora community 10. Querus mongolica Community 1) Rhododendron schlippenachii subcommunity 2) Lenedeza maximowiczii subcommunity 11. Abies nephrolepis community 12. Abies koreana community 1) Querus mongolica subcommunity 2) Pinus koraienis subcommunity 13. Rhododendron schlippenbachii community Among above forest communities, Querus serrata community distributed from 700m to 1,000m in the ridges, Carpinus laxiflora community in the valleys, Quercus mongolica community from 1,000m to 1,400m, and Abies koreana community and Abies nephrolepis community from 1,400m to 1,700m.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.698-701
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• 2020

여러 대의 자율주행 차량이 하나의 그룹을 형성하여 주행하는 군집주행은 미래 고속도로 교통 시스템의 핵심 기술이다. 이러한 군집주행에서 발생할 수 있는 다양한 상황에서의 안전을 고려하는 일은 단독 자율 주행에서의 경우보다 더 어렵다. 다양한 군집주행의 안전 위협 요인 중, 의도하지 않은 동작으로부터 자율주행 차량의 안전성을 향상하는 방법을 가이드하기 위하여 새로운 표준 ISO/PAS 21448이 제정되었다. 본 논문에서는 ISO/PAS 21448 표준이 다루는 시나리오를 통해 군집주행에서 발생할 수 있는 의도하지 않은 상황의 극복을 위한 방법을 제시하였다. 특히 군집주행 시뮬레이터인 VENTOS를 이용하여 본 논문에서 제시하는 방법이 안전한 군집주행이라는 목표를 달성할 수 있음을 확인하였다.

• The Journal of the Korea Contents Association
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• v.12 no.12
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• pp.733-741
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• 2012

In recent, many consumers visit the online shopping malls or price comparison sites to collect the information on the product category that they are interested in. However, the volumes of the data provided by such web sites are often too enormous, and significant number of consumers have trouble in making purchase decision based on the plethora of products and sellers. In this context, modern online shopping agents need to process the retrieved information in more intelligent way before providing them to the users. This paper proposes a novel approach for identifying the main price ranges hidden in a single product category. To this end, the price of an item in the category is represented as a row vector and k-means clustering analysis is applied to the price vectors to produce the clusters that consists of the product items with similar price vectors. Then, the main price ranges of the product category can be identified from the result of clustering analysis. In general, the price is one of the most important factors in the consumers' purchase decision, and the identified main price ranges will be helpful for the online shoppers to find appropriate items effectively.