• The Journal of Engineering Geology
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• v.25 no.4
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• pp.533-545
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• 2015

Spatial and seasonal variations in hydrogeochemical characteristics and the factors affecting the deterioration in quality of shallow portable groundwater in an agricultural area are examined. The aquifer consists of (from the surface to depth) agricultural soil, weathered soil, weathered rock, and bedrock. The geochemical signatures of the shallow groundwater are mostly affected by the NO₃⁻ and Cl⁻ contaminants that show a gradual downward increase in concentration from the upper area, due to the irregular distribution of contamination sources. The concentrations of the major cations do not varied with the elapsed time and the NO₃⁻ and Cl⁻ ions, when compared with concentrations in background groundwater, increase gradually with the distance from the upper area. This result suggests that the water quality in shallow groundwater deteriorates due to contaminant sources at the surface. The contaminations of the major contaminants in groundwater show a positive linear relationship with electrical conductivity, indicating the deterioration in water quality is related to the effects of the contaminants. The relationships between contaminant concentrations, as inferred from the ternary plots, show the contaminant concentrations in organic fertilizer are positively related to concentrations of NO₃⁻, Cl⁻, and SO₄²⁻ ions in the shallow portable groundwaters, which means the fertilizer is the main contaminant source. The results also show that the deterioration in shallow groundwater quality is caused mainly by NO₃⁻ and Cl⁻ derived from organic fertilizer with additional SO₄²⁻ contaminant from livestock wastes. Even though the concentrations of the contaminants within the shallow groundwaters and the contaminant sources are largely variable, it is useful to consider the ratio of contaminant concentrations and the relationship between contaminants in groundwater samples and in the contaminant source when analyzing deterioration in water quality.

• Journal of Korea Entertainment Industry Association
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• v.13 no.7
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• pp.307-319
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• 2019

This study aims to provide the basic materials for the development of leisure and tourism contents in connection with Osaek cableway for the revitalization of Osaek District. For such a purpose, the following policy directions were presented through the analysis of the present situation and conditions of Osaek District, the direction of development of leisure and tourism contents of Osaek District, etc. The first is increasing the participation of local residents and reinforcing their capabilities. The suggested promotion plans are ① establishing organizational system and strengthening support, ② reinforcing the capabilities of local residents and ③ constructing networks with external human resources. The second is setting the guidelines for contents development. It was proposed to prepare contents for leisure experience using the natural environment of Osaek District in response to the trend of increase of people who enjoy "contents using culture and arts" and leisure. The third is typological approach to contents. It was proposed to develop cultural contents with the theme of Osaek such as "Osaek Light Festival", "Osaek Concert", "Osaek Photo Exhibition" and "Osaek Good Men and Women Contest" for the promotion of the brand of the place name of Osaek and the creation of the "Picture Book Village" for the compilation of the history and culture of Osaek District with pictures. The fourth is securing marketing channels. For this, it was proposed to produce the website of Yangyang County or a website tentatively named as "Osaek-ri with Beautiful Osaek" and introduce an integrated travel product (transportation + lodging + foods + experience (hot spring, mineral water therapy, leisure experience, etc.) + purchasing local specialty products, etc.) composed of the leisure and tourism contents, transportation, lodging, foods, etc. of Osaek District through travel agencies. The final policy direction presented was phased implementation of the development and operation of the contents. Proposed policies include support of a consulting project to upgrade the organization of local residents; implementation of "Tourism Dure (Cooperative)" project for the solution of the problem of tourism in Osaek District by the residents themselves together using the space of culture and arts made by remodeling idle public and private facilities after benchmarking exemplary places; system improvement for the introduction of leisure and tourism contents appropriate for local conditions; and the establishment of a master plan for the introduction of various leisure and tourism contents in Osaek District.

• Journal of Environmental Impact Assessment
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• v.27 no.6
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• pp.674-684
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• 2018

The purpose of this study is to construct ecological pond using LID technique in order to create naturally comfortable community space in urban idle space. The specification of the ecological pond is $110m^2$ of surface area, $0.45{\pm}0.02m$ of average depth, and bed material is composed of gravel (diameter ${\leq}60mm$), sand (diameter ${\leq}2mm$) and bentonite. Rainfall and water depth monitoring were conducted to determine the annual characteristics of inflow of the water for the ecological pond, result of total rainfall was 1,287 mm and showed a seasonal imbalance that accounted for 71.3% (918 mm) during July to August, but the annual mean water depth was kept constant at $0.45{\pm}0.02m$ due to the secondary water source. Annual trends of basic water quality showed a significant changes according to the season, such as water temperature ($5.2{\sim}28.8^{\circ}C$), DO (5.0 ~ 13.8 mg/L), EC ($113{\sim}265{\mu}S/cm$). BOD, COD, TN, and TP in physicochemical water quality tended to increase after October, but the ion parameters such as $NH_3$ and $PO_4{^{3-}}$ were generally low. Phytoplankton indicators Chl-a and BGA (blue green algae) showed a sharp increase from July to August, and green algae (Selenastrum bibraianum, Pediastrum boryanum etc.) and filamentous blue green algae (Phormidium sp.) emerged as a dominant species. The ion parameters ($F^-$, $Na^+$, $K^+$, $Mg^{2+}$, $Ca^{2+}$) were strongly correlated with the $Cl^-$ as a conservative substance (R=0.70~0.97, p<0.05). Water quality was influenced by the ambient environment such as seasonal changes or rainfall, and it was closely related to fluctuation of the inflow of the water. In the future, it is necessary to consider ecological connections by referring to the characteristics surveyed in this study in order to effectively manage the water quality and biodiversity of the ecological pond in idle space.

• Tunnel and Underground Space
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• v.13 no.4
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• pp.270-278
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• 2003

Transparency on the Total System Performance Assessment (TSPA) is the key issue to enhance the public acceptance for a permanent high level radioactive repository. Traditionally, the study on features, events and processes (FEPs) and associated scenarios has been regarded as the starting point to open the communicative discussion on TSPA such as what to evaluate, how to evaluate and how to translate outcomes into more friendly language that many stakeholders can easily understand and react with. However, in most cases, it has been limited to one way communication, because it is difficult for stakeholders outside the performance assessment field to assess the details on the story of the safety assessment, scenario and technical background of it. Fortunately, the advent of the internet era opens up the possibility of two way communication from the beginning of the performance assessment so that every stakeholder can exchange their keen opinions on the safety issues. To achieve it, KAERI develops the systematic approach from the FEPs to Assessment methods flow chart. All information is integrated into the web based program named FEAS (FEp to Assessment through Scenario development) under development in KAERI. In parallel, two independent systems are also under development the web based QA(Quality Assurance) system and the PA(Performance Assessment) input database. It is ideal to integrate the input data base with the QA system so that every data in the system can checked whenever necessary. Throughout the next phase R&D starting from the year 2003, these three systems will be consolidated into one unified system.

• Korean Journal of Optics and Photonics
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• v.35 no.3
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• pp.107-114
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• 2024

In this study, the feasibility of using the covariance-matrix-adaptation-evolution-strategy (CMA-ES) algorithm in a multichannel coherent-beam-combining (CBC) system was experimentally verified. We constructed a multichannel CBC system utilizing a spatial light modulator (SLM) as a multichannel phase-modulator array, along with a coherent light source at 635 nm, implemented the stochastic-parallel-gradient-descent (SPGD) and CMA-ES algorithms on it, and compared their performances. In particular, we evaluated the characteristics of the CMA-ES and SPGD algorithms in the CBC system in both 16-channel rectangular and 19-channel honeycomb formats. The results of the evaluation showed that the performances of the two algorithms were similar on average, under the given conditions; However, it was verified that under the given conditions the CMA-ES algorithm was able to operate with more stable performance than the SPGD algorithm, as the former had less operational variation with the initial phase setting than the latter. It is emphasized that this study is the first proof-of-principle demonstration of the CMA-ES phase-control algorithm in a multichannel CBC system, to the best of our knowledge, and is expected to be useful for future experimental studies of the effects of additional channel-number increments, or external-phase-noise effects, in multichannel CBC systems based on the CMA-ES phase-control algorithm.

• Korean Journal of Environment and Ecology
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• v.34 no.2
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• pp.170-178
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• 2020

There are few landscape ecological analyses of Khingan fir (Abies nephrolepis) and other habitats of the sub-alpine zone in South Korea. In this study, we tried to quantitatively interpret and assess the habitat characteristics by analyzing 15 landscape indices according to the differences in tree layer coverage, in the Khingan fir habitat growing naturally in the sub-alpine zone of Seoraksan National Park. It was difficult to identify the tendency of landscape ecology to increase and decrease the tree layer coverage in the study site, which was the entire Khingan fir habitat in Seoraksan National Park. However, the Khingan fir habitat was found to be generally low in coverage, and population density as the tree layer coverage of less than 50 percent accounts for 85 percent of the total habitat. Moreover, the Khingan fir habitat in the 10 to 50 percent range was fragmented into a total of 286 patches, making it relatively less connected to the habitat. The total edge length and edge density, which could determine the edge effect of the main part according to the physical form, were the highest in the habitat of 26 to 50 percent coverage, indicating a relatively high impact from outside than habitats of other coverages. The shape with the tree layer coverage of between 10 and 50 percent was more complex even with patches of the same size, and it is believed that these characteristics make it more susceptible to habitat fragmentation and external confounding. We expect that the results of this study can be useful for time series analysis of spatial expansion or reduction of the Khingan fir habitat in Seoraksan National Park and provide the reference data for the morphological change and movement of patches and the connectivity and break-off between forests.