• Economic and Environmental Geology
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• v.55 no.4
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• pp.367-376
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• 2022

One of biopolymer, β-glucan (BG) chains were crosslinked by citric acid under the heating condition for the adsorption of Pb and Cu ions in the aqueous solution. The variation of functional groups on BG itself and crosslinked β-glucan (CBG) with their surface adsorption characteristics were investigated by FTIR and SEM-EDX. Adsorption kinetic results showed that adsorption of Pb and Cu onto the CBG followed the pseudo-second-order kinetic model and intra-particle diffusion model. The Langmuir adsorption model was depicted better adsorption characteristics than the Freundlich model. The adsorption capacities of Pb and Cu onto the CBG estimated by the Langmuir model were 59.70 and 23.44 mg/g, respectively. This study suggested that CBG may act as an eco-friendly adsorbent for the adsorption of Pb and Cu in the aqueous solution.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.1068-1071
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• 2005

최근 들어 기술을 담보로 하는 신용금융의 역할이 증대되면서 자금지원 대상기업의 기술평가 시스템 구축이 중요한 과제가 되고 있다. 국내에서는 기업 보유의 기술경영성과를 측정하여 한정된 자원의 효율적 배분을 위한 민간 투, 융자를 위한 기술신용평가모형'이 제시되었다 본 연구에서는 기술신용평가모델의 평가항목 타당성을 실증 분석한다. 모형의 항목 분류가 적절하게 되었는지를 검증하기 위하여 구조적 타당성을 평가하며 통계적 유의성을 검증하여 신뢰성을 평가한다. 구조적 타당성 검정을 위해 확인 요인분석을 수행하며 평가모형의 신뢰성을 검증하기 위해서는 다변량 통계방법 중의 하나인 판별분석을 수행한다. 본 연구는 기술개발 성공 및 부실발생의 예측력을 갖는 기술신용평가 시스템 구축을 위한 기초 자료로 활용될 수 있을 것이다.

• The KIPS Transactions:PartA
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• v.13A no.6 s.103
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• pp.511-516
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• 2006

The data grid computing provides geographically distributed storage resources to solve computational problems with large-scale data. Unlike cache replacement policies in virtual memory or web-caching replacement, an optimal file replacement policy for data grids is the one of the important problems by the fact that file size is very large. The traditional file replacement policies such as LRU(Least Recently Used) LCB-K(Least Cost Beneficial based on K), EBR(Economic-based cache replacement), LVCT(Least Value-based on Caching Time) have the problem that they have to predict requests or need additional resources to file replacement. To solve theses problems, this paper propose SBR-k(Sized-based replacement-k) that replaces files based on file size. The results of the simulation show that the proposed policy performs better than traditional policies.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.9
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• pp.973-980
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• 2015

With their wide geographical distribution, unconventional resources are continuously compared against conventional resources, but their development is expanding because TRRs (Technical Recoverable Resources) are similar to conventional resources. In particular, there is active development of unconventional gas resources such as shale gas, tight gas, CBM (coalbed methane) and gas hydrate. However, it is difficult to calculate the material properties of unconventional resources, especially the gas content, with current geophysical logging technology. Additionally, some overseas companies have monopolies on related equipment and materials. Therefore, this study developed a reservoir PCS (Pressure Core Sampler). It can collect core samples without gaseous loss by maintaining high pressure from the moment the core is sampled and record pressure and temperature in real time. Successful performance testing was also carried out for official verification of the manufactured PCS. The reservoir PCS will contribute to the acquisition of geophysical well logging data as well as accurate and reliable cores.

• Economic and Environmental Geology
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• v.47 no.6
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• pp.635-643
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• 2014

Sustaiable development yield of groundwater in Korea has been determined according to 10 year drought frequency of groundwater recharge in the standard mid-sized watershed or relatively large area of district. Therefore, the evaluation of groundwater impact in a small watershed is hard to apply. Fot this purpose, a novel approach to estimate cell based sustainable development yield of groundwater (SDYG) is suggested and applied to Gyeongju region. Cell based groundwater recharge is computed using hydrological component analysis using the SWAT-MODFLOW which is an integrated surface water-groundwater model. To estimate the potential amount of groundwater development, the existing method which uses 10 year drought frequency rainfall multiplied by recharge coefficient is adopted. Cell based SDYGs are computed and summed for 143 sub-watersheds and administrative districts. When these SDYGs are combined with groundwater usage data, the groundwater usage rate (total usage / SDYG) shows wide local variations (7.1~108.8%) which are unseen when average rate (24%) is only evaluated. Also, it is expected that additional SDYGs in any small district could be estimated.

• Korean Journal of Environmental Biology
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• v.38 no.1
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• pp.30-39
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• 2020

The changes in fish stock and biomass before and after fishway renovation located in a Korean estuary were studied and fluctuations in the economic value of the fish resources were estimated. The target fishway located in the east coast area in Korea was renovated in 2014 from the small fish ladder to the ice-harbor fishway. Monitoring was continued for five consecutive years after the renovation(2015 to 2019). Since the renovation of the fish passage, the economic values increased with increases in the fishery resources, except for in 2016 when the drought impact was severe. The yearly average incremental increase in the five years after the renovation was about 227%. The increase in economic value is believed to be due to the increased population of migratory fish as a result of habitat expansion. The exponential rise model showed an increase in economic value with increasing fishery resources (R²=0.896). The model coefficient contributing to economic analysis was 0.582 and the maximum economic value after the renovation was estimated at about 30.4 million. The economic value would be a useful index for quantitative comparison in terms of ecosystem services before and after renovation.

• Journal of the Korean Wood Science and Technology
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• v.30 no.4
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• pp.23-26
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• 2002

The generation of wastewood is currently about 40% level of the amount of domestic wood use. When the rate of wood self-supply is considered, the recycling of wastewood in wood panel products industry should be encouraged. This study was evaluated the performance of particleboard (PB) made from wastewood. PBs were manufactured with the synthesized urea-formaldehyde resin at 5 minutes hot-press time, and at 162℃ press temperature with 6 percent resin solids level on an ovendry wastewood particle weight basis. The PBs were tested by the procedure of ASTM D 1037. Test results exceeded the minimum strength requirement according to KS F 3104 Particleboard type 8.0. The PB's performance showed that wastewood is suitable raw material for PB.

• Journal of the Korean Geotechnical Society
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• v.39 no.6
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• pp.13-19
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• 2023

Lunar ice is a resource available for future human exploration in deep space and long-term extraterrestrial habitat. However, the origin and nature of lunar ice remains unclear. In addition to remote sensing, international space agencies are competitively planning and conducting missions for lunar surface exploration to determine the existence and resource extent of lunar ice. If a sufficient amount of lunar ice is confirmed, its future in-situ resource utilization is expected to be greatly beneficial. However, due to ice extraction, settlement may occur, which should be taken into account from a geotechnical engineering perspective. Herein, experimental investigations of the potential settlement caused by lunar ice extraction were conducted and different textures of lunar ice were simulated. Consequently, it was confirmed that significant settlement occurs even at the initial water content of ~10% in lunar regolith simulant-ice-mixed soil.

• Annual Conference on Human and Language Technology
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• 2020.10a
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• pp.321-326
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• 2020

본 연구에서는 한국어 감성분석 성능 향상을 위한 DECO(Dictionnaire Electronique du COreen) 한국어 전자사전과 LGG(Local-Grammar Graph) 패턴문법 기술 프레임에 의존파서 및 LSTM을 적용하는 하이브리드 방법론을 제안하였다. 본 연구에 사용된 DECO-LGG 언어자원을 소개하고, 이에 기반하여 의미 정보를 의존파서(D-PARS)와 페어링하는 한편 OOV(Out Of Vocabulary)의 문제를 LSTM을 통해 해결하여 자질기반 감성분석 결과를 제시하였다. 부트스트랩 방식으로 반복 확장될 수 있는 LGG 언어자원 및 알고리즘을 통해 수행되는 자질기반 감성분석 프로세스는 전용 플랫폼 DecoFESA를 통해 그 범용성을 확장하였다. 실험을 위해서 네이버 쇼핑몰의 '화장품 구매 후기글'을 크롤링하였으며, DecoFESA 플랫폼을 통해 현재 구축된 DECO-LGG 언어자원 기반의 감성분석 성능을 평가하였다. 이를 통해 대용량 언어자원의 구축과 이를 활용하기 위한 어휘 시퀀스 처리 알고리즘의 구현이 보다 정확한 자질기반 감성분석 결과를 제공할 수 있음을 확인하였다.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.1
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• pp.68-75
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• 2016

The present study evaluated the mechanical properties of open graded asphalt for semi-rigid pavements in order to determine the mixing proportion experimentally. A total twelve types of basic mixing proportions were set up and mechanical tests such as marshall stability, porosity, permeability, and cantabro loss were conducted based on Korean standards. From the tests results, it was found that the marshall stability in case of straight and modified asphalt increase up to the contents with 5.0% and 5.5% respectively. The porosity and permeability of asphalt tended to decrease as the asphalt contents increase, the coefficient of correlation between both were estimated 86%. The increase contents with asphalt range from 3.5% to 6.0% tended to decrease the cantabro loss and the modified asphalt enhanced the resistance of cantabro loss with range from 18.8% to 33.1% than straight asphalt under same asphalt contents. In comparison with test results and quality standards, it was concluded that the modified asphalt content of 4.5% is effective to adopt for open graded asphalt.