• Journal of Korean Society of Forest Science
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• v.87 no.3
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• pp.366-371
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• 1998

To investigate the structure of Korean native species, Abies koreana forest in subalpine zone of Mt. Halla, 20 plots ($10{\times}10m$) set up with random sampling method were surveyed. The forest on subalpine zone in Mt. Halla was Abies koreana - Taxus cuspidata - Sasa quelpaertensis community. High positive correlations were shown between Quercus ${\times}$ grosseserrata and Carpinus laxiflora; Carpinus laxiflora and Acer pseudo-sieboldianum, Ilex crenata; Taxus cuspidata and Rhododendron mucronulatum var. ciliatum, Prunus padus, and high negative correlations were shown between Abies koreana and Quercus ${\times}$ grosseserrata; Abies koreana and Acer pseudo-sieboldianum; Sasa quelpaertensis and Prunes sargentii. Vigor of Abies koreana was depressed, 8.11% of total number of Abies koreana investigated were dead. DBH of dead individuals ranged mainly 10-30 cm.

• The Journal of the Convergence on Culture Technology
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• v.2 no.1
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• pp.93-98
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• 2016

As information technologies are rapidly developed recently, social networking services through a variety of mobile devices and smart screen is becoming popular. SNS is a social networking based services which is online forms from existed offline. SNS can also be used differently which is confused with the online community. A modelling algorithm is a variety of techniques, which are assocoation, clustering, neural networks, and decision trees, etc. By utilizing this technique, it is necessary to study to effectively using the large number of materials. In this paper, we evaluate in particular the performance of the algorithm based on the results of the clustering using Facebook Insights data for the EM algorithm to be evaluated as a good performance in clustering. Through this analysis it was based on the results of the application of the experimental data of the change and the South Australian state library according to the performance of the EM algorithm.

• Korean Journal of Ecology and Environment
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• v.39 no.2 s.116
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• pp.157-166
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• 2006

Characteristics of ichthyofauna and fish community in the Lagoon Gyeongpo, Korea, were investigated from May to October 2005. Total 26 species caught during the period were belonged to 18 families. Dominant species was T. hakonesis (50.7%) and subdominant species was A. flavimaus (25.4%). K. punctatus (11.1%), M. cephalus (6.5%), E. japonicus (1.5%), C. castaneus (1.0%) were also numerous. Total biomass of collected fish was 401.8 kg, and biomass of each species was T, hakonensis 147.0 kg, A. flavimanus 135.8 kg, K. punctatus 85.6 kg and M. cephalus 23.8 kg. Seasonal variation of fish community seems to be related to spawning periods of species. In conclusion, it appeared that the ratio of the primary freshwater species was gradually decreased, while the peripheral freshwater and seawater species were gradually increased when compared to the data obtained from the past with respect to the ichthyofauna of the Lagoon Gyeongpo.

• Journal of Korea Water Resources Association
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• v.51 no.5
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• pp.383-393
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• 2018

The regional frequency analysis is the method which uses not only sample of target station but also sample of neighborhood stations in which are classified as hydrological homogeneous regions. Consequently, identification of homogeneous regions is a very important process in regional frequency analysis. In this study, homogeneous regions for regional frequency analysis of precipitation were identified by the self-organizing map (SOM) which is one of the artificial neural network. Geographical information and hourly rainfall data set were used in order to perform the SOM. Quantization error and topographic error were computed for identifying the optimal SOM map. As a result, the SOM model organized by $7{\times}6$ array with 42 nodes was selected and the selected stations were classified into 6 clusters for rainfall regional frequency analysis. According to results of the heterogeneity measure, all 6 clusters were identified as homogeneous regions and showed more homogeneous regions compared with the result of previous study.

• Korean Journal of Environment and Ecology
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• v.4 no.1
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• pp.23-32
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• 1990

To investigate the structure of the pine forest community and the conservation of pine forest in Mt. Sokri, twenty plots of 500$m^2$ size set up by the clumped sampling method. The classification by TWINSPAN and DCA ordination were applied to the study area in order to classify them into several groups based on environmental variables. The plant community was not classified into several groups by above methods in this study area. The successional trends of tree species by both techniques seem to be from Pinus densiflora through Quercus serrata, Fraxinus sieboldiana, Q. aliena, Sorbus alnifolia, Prunus sargentii to Carpinus laxiflora, C. cordata in the canopy layer. and from Rhus trichocarpa, Lindera obtusiloba through Styrax obassia, Acer pseudosieboldiana, Symplocos chinensis for. pilosa to L. erythrocarpa, Viburnum erosum in the understory layer. Pinus densiflora community shall be conserved by the disclimax method, i. e. the broadleaf vegetation in the underlayer of the pine community should be cleared out.

• Journal of the Korea Society of Computer and Information
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• v.26 no.2
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• pp.201-211
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• 2021

In this paper, we propose that logistics companies will have different business models when using blockchain technology. In addition, it intends to understand the difference in absorptive capacity and performance of logistics companies using blockchain technology. In order to achieve this research objective, this study conducted a survey on logistics companies and analyzed the collected data. Cluster analysis was performed to understand the business model, and ANOVA was performed to understand the significance of cluster analysis. The difference in absorptive capacity and performance was analyzed according to the business model identified through cluster analysis. In addition, PLS analysis was conducted to determine the difference in absorption capacity and performance. The results show that logistics companies have different types of business models in adopting blockchain technology. Logistics companies groups with high degree of development of business models showed high results in terms of absorption capacity and performance level.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.17-17
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• 2023

국내의 부지특성 및 감시 관련 규정은 원자력 안전위원회 고시 제2021-16호 제4조(세부지침)와 원자력 안전위원회 고시 제2021-17호 제16조에 의거하고, 국외는 국제원자력기구(IAEA: International Atomic Energy Agency)에서 안전기준을 제시하고 있다(IAEA, 2011). 따라서 국내 중·저준위 방사성폐기물 처분시설은 2006년부터 광역 지질을 포함한 부지 지질/지형, 기상, 수문, 수리지질, 인문사회 등을 망라한 조사를 시행하여 부지 현황에 대한 분석 및 안정성 평가를 수행한다. 부지감시의 수문·지구화학 분야에서는 현장 수질 측정 6항목과 실내 분석 26항목을 감시하고 있으나, 본 연구는 이 중 9개 항목(EC, Na, K, Ca, Mg, SiO₂, Cl, SO₄, HCO₃)을 선정하여 분석하였다. 연구 목적은 물시료 분석자료의 주성분-다중선형회귀-군집 분석과 Piper Diagram 분석결과로부터 해수와 담수(지하수)와의 특성분석 및 해수 영향을 분석하는 것이다. 현장 부지내 지하수 7개 관정(GM-1, 2, 4, 5, 6, 7, 8)과 해수 2개 지점(Sea-1, 2)을 대상으로 통계학적 주성분 분석결과, 대부분의 지하수는2개~4개의 요인으로 구분되고, 해수와의 유사성을 해석하기 위해 확인한 관정은 GM-5, GM-6, GM-1 지점으로 분류되었다. 상기와 같이 해수의 영향을 확인하기 위해 해수 2개 지점과 동일한 군집으로 분류되는 지하수는 GM-5 관정으로 확인되었고, 해안선에서 가까운 GM-5 관정과 같이 유사한 거리에 분포한 지하수 GM-1, 2, 4 관정은 2개 혹은 3개의 최적 군집으로 분류하였을 때도 GM-5와는 다른 특성을 보여주었다. 이는 해안과 인접하더라도 수질은 다른 지질학적 특성(지형, 기상, 단열대 등)에 따라 영향받았음을 지시한다.

• Journal of the Korean Regional Science Association
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• v.39 no.1
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• pp.3-20
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• 2023

This study aims to categorize the 14 major gentrified commercial areas of Seoul and analyze their characteristics based on their sense of place. To achieve this, we conducted hierarchical cluster analysis using text data collected from Naver Blog. We divided the districts into two dimensions: "experience" and "feature" and analyzed their characteristics using LDA (Latent Dirichlet Allocation) of the text data and statistical data collected from Seoul Open Data Square. As a result, we classified the commercial districts of Seoul into 5 categories: 'theater district,' 'traditional cultural district,' 'female-beauty district,' 'exclusive restaurant and medical district,' and 'trend-leading district.' The findings of this study are expected to provide valuable insights for policy-makers to develop more efficient and suitable commercial policies.

• Korean Journal of Environmental Biology
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• v.40 no.4
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• pp.591-603
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• 2022

This study was conducted to identify changes of insect compositions and diversity after construction of an onshore wind farm. We investigated insect fauna and compositions between a grassland deforested by the construction and a forest located at Yeongdeok and Yeongyang, Gyeongsangbuk-do, Korea. Insects were collected using a sweeping net and light trap. A total of 11 orders, 50 families, and 246 species, and 1,076 individuals were collected at study sites. By taxonomic group, Lepidoptera species were the most frequently found with 141 species, 417 individuals (38.8%), followed by Hymenoptera (20.6%), Hemiptera (16.2%), and Orthoptera (12.3%). There were also significant differences in insect species and community compositions between sites. Creating open-field deforested forests are beneficial for some insect groups such as Hymenoptera and Orthoptera. Our results suggest that deforesting by the construction of an onshore wind farm might affect the composition and diversity of insects. Results of this study provide basic data for research on onshore wind farms.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.1
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• pp.91-98
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• 2023

Since risks occurring in construction projects can have a significant impact on schedules and costs, there have been many studies on this topic. However, risk analysis is often limited to only certain construction situations,and experience-dependent decision-making is therefore mainly performed. Data-based analyses have only been partially applied to safety and contract documents. Therefore, in this study, cluster analysis and a Word2Vec algorithm were applied to formal documents that contain important elements for contractors or clients. An initial classification of document content into six types was performed through cluster analysis, and 157 occurrence types were subdivided through application of the Word2Vec algorithm. The derived terms were re-classified into five categories and reviewed as to whether the terms could develop into potential construction risk factors. Identifying potential construction risk factors will be helpful as basic data for process management in the construction industry.