• Journal of Applied Biological Chemistry
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• v.60 no.1
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• pp.49-54
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• 2017

In the course of screening tyrosinase inhibitory activity, EtOAc-soluble fraction of Coix lachryma-jobi var. mayuen Stapf. (Gramineae) roots showed significant inhibition. Further fractionation of the EtOAc-soluble fraction resulted in six compounds, which were identified as (+)-icariol $A_2$ (1), zhepiresionol (2), 4-hydroxybenzaldehyde (3), trans-${\rho}$-coumaric acid (4), N-(2-hydroxy-4-methoxyphenyl)-2-hydroxyacetamide (5), and coixol (6). The chemical structures of these compounds were identified on the basis of spectroscopic methods (MS, 1D and 2D NMR) and comparison with literature values. Compound 1 was first reported from this plant. Also, this is the first time that the isolation of compound 5 has been reported from nature source. Among the isolated compounds, compounds 4 and 6 showed enzyme inhibitory activity, with $IC_{50}$ values of 6.5 and $62.4{\mu}M$, respectively, in comparison with these of positive control, arbutin.

• Journal of the Korean Magnetics Society
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• v.20 no.5
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• pp.173-177
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• 2010

The electronic structure of charge-density-wave (CDW) system $CeTe_2$ has been investigated by using angle-resolved photoemission spectroscopy (ARPES). The clearly dispersive band structures are observed in the measured ARPES spectra, indicating the good quality of the single-crystalline sample employed in this study. The four-fold symmetric patterns are observed in the constant energy (CE) mappings, indicating the $2{\times}2$ lattice deformation in the Te(1) sheets. The observed CE images are similar to those of $LaTe_2$, suggesting that Ce 4f states have the minor contribution to the CDW formation in $CeTe_2$. This study reveals that the carriers near the Fermi level should have mainly the Te(1) 5p and Ce 5d character, that the Te(1) 5p bands contribute to the CDW formation, and that the Ce 5d bands cross the Fermi level even in the CDW state.

• KIPS Transactions on Software and Data Engineering
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• v.5 no.1
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• pp.21-28
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• 2016

The performance of an English-Korean machine translation system depends heavily on its English parser. The parser in this paper is a part of the rule-based English-Korean MT system, which includes many syntactic rules and performs the chart-based parsing. The parser generates too many structures due to many syntactic rules, so much time and memory are required. The rule-based parser has difficulty in analyzing and translating the long sentences including the commas because they cause high parsing complexity. In this paper, we propose the 3-phase parsing method with sentence segmentation to efficiently translate the long sentences appearing in usual. Each phase of the syntactic analysis applies its own independent syntactic rules in order to reduce parsing complexity. For the purpose, we classify the syntactic rules into 3 classes and design the 3-phase parsing algorithm. Especially, the syntactic rules in the 3rd class are for the sentence structures composed with commas. We present the automatic rule acquisition method for 3rd class rules from the syntactic analysis of the corpus, with which we aim to continuously improve the coverage of the parsing. The experimental results shows that the proposed 3-phase parsing method is superior to the prior parsing method using only intra-sentence segmentation in terms of the parsing speed/memory efficiency with keeping the translation quality.

• Korean Chemical Engineering Research
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• v.44 no.2
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• pp.172-178
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• 2006

Mesoporous silicate materials have been used as adsorbents for the removal of heavy metals from water by introducing functional groups such as thiol and amine. In this research, it was investigated whether surfactants used as templating agents in synthetic processes can act as adsorption sites for heavy metals. Three mesoporous silicates-SBA-15, MCM-41, and HMS were synthesized using, respectively, block copolymer, hexadecyltrimethylammoniumbromide (HDTMA), and dodecyamine as surfactants. X-ray diffraction and $N_2$ gas adsorption analysis confirmed that the mesoporous silicates were well prepared and FT-IR spectra resulted in the existence of the surfactants in as-synthesized mesoporous silicates and the removal of surfactants after calcination. The interactions between $Pb^{2+}$ ions and the mesoporous silicate materials with/without surfactants were observed. In adsorption kinetic experiments, it revealed that the calcined mesoporous silicates and the surfactant-loaded SBA-15 almost had no adsorption capacity for $Pb^{2+}$ ions. In contrast, the surfactant-loaded MCM-41 and HMS showed, respectively, the adsorption capacities of 26.60 and 115.16 mg/g which were acquired through the fits of adsorption kinetic data to the pseudo second order kinetic model. The adsorption capacities were comparable to those of other mesoporous adsorbents for heavy metals.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.68-73
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• 2016

This study was conducted to identify trends and knowledge structures associated with recent trends in Korean tourism from 2010 to 2015 using keyword data. To accomplish this, we constructed a network using keywords extracted from KCI journals. We then made a matrix describing the relationships between rows as papers and columns as keywords. A keyword network showed the connectivity of papers that have included one or more of the same keywords. Major keywords were then extracted using the cosine similarity between co-occurring keywords and components were analyzed to understand research trends and knowledge structure. The results revealed that subjects of tourism research have changed rapidly and variously. A few topics related to 'organization-employee' were major trends for several years, but intrinsic and extrinsic factors have been further subdivided and employees of specific fields have been targeted as subjects of research. Component analysis is useful for analyzing concrete research topics and the relationships between them. The results of this study will be useful for researchers attempting to identify new topics.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.394-394
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• 2015

급격히 변화하고 있는 산업화와 도시화로 지구 온난화 현상으로 기상이변의 발생빈도가 높아졌고 기후가 불안정하여 예전보다 많은 집중호우가 발생하면서, 홍수로 인한 제내지 침수가 발생되기도 한다. 기후변화로 인한 수재해에 대응하기 위하여 하천 호소 수리 예측 모형의 개선이 필요한 실정이다. 하지만, 자연하천 유역의 강우-유출 상관관계와 지표면 유출현상 및 하도 수리 특성을 자연현상의 복잡성, 강우발생의 시간적 공간적인 발생과정의 임의성, 정확한 해석방법 및 확률 분석에 따르는 불확실성 들을 토대로 단순한 이론과 제한적인 경험공식 등에 의해서 해석, 재현 및 평가를 한다는 것은 매우 어려운 문제이다. 최근 IT 기술의 발전과 더불어, 많은 연구자, 엔지니어들이 기존 수리 수문학적 지식과 IT기술을 융합하여 복잡 다단한 수자원 환경 문제를 해결하고자 한다. 이와 같은 최근 연구 동향에 의거하여, 본 연구에서는 HEC-RAS, TELEMAC-2D 1, 2차원 수리 모형을 연계하여 하천 흐름 분석 및 홍수 범람 해석에 적용하였다. 본 연구에서는 HEC-RAS, TELEMAC 모형을 적용하여 2012년 태풍 '산바(SANBA)'로 인해 홍수 피해를 입은 고령군에 위치한 낙동강 본류 회천 유역(상류 회천교 ~ 하류 도진교)의 하도 내 흐름 분석과 하천 인근 제내지 홍수범람을 예측하였다. 범람해석에 필요한 지형자료를 기초로 하여 각 지형의 조건에 맞게 수치자료를 이용하여 작성하였고, 수자원 정보를 이용하여 유랑, 수위 등 시계열자료를 지류 및 상 하류의 경계조건으로 설정하고, 조도계수 등 하천 기본정보들을 입력하였다. HEC-RAS 모형은 회천교부터 도진교까지 전구간에 대한 종단면과 횡단면별 홍수침수범위 및 홍수위 크기 등 거시적인 1차원 수리해석에 적용하였고, TELEMAC 모형은 HEC-RAS 시뮬레이션 결과를 바탕으로 HEC-RAS에서 나타내기 힘든 2차원 흐름특성, 침수현상 등 일부 범람 구간에 대해 수리해석에 적용하였다. HEC-RAS 시스템은 수공구조물들의 영향과 하천의 영향을 종 횡단면으로 다양한 홍수침수 범위를 1차원으로 나타 낼 수 있으며, TELEMAC 시스템 수리 모의를 통해 얻어진 결과는 유속, 유량, 수심, 하상고 높이 등 2차원으로 나타낼 수 있다. TELEMAC 시스템을 활용한 2차원 분석은 실측자료와 비교적 유사하고 시각, 공간적으로 이해하기 쉽게 표현되므로, 모형 적용성이 우수한 것으로 판단된다. 향후 유역 해석을 위한 수치데이터, 수위, 유량자료를 확보하여 HEC-RAS, TELEMAC 1, 2차원 연계 모형을 적용 한다면, 하천 준설, 하천 구조물 설치, 홍수피해 등 전반적인 하천관리 계획에 활용할 수 있을 것이라 판단된다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.846-855
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• 2021

Eco-friendly and renewable energy sources are actively being researched in recent times, and of shore wind power generation requires advanced design technologies in terms of increasing the capacities of wind turbines and enlarging wind turbine installation vessels (WTIVs). The WTIV ensures that the hull is situated at a height that is not affected by waves. The most important part of the WTIV is the leg structure, which must respond dynamically according to the wave, current, and wind loads. In particular, the wave load is composed of irregular waves, and it is important to know the exact dynamic response. The dynamic response analysis uses a single degree of freedom (SDOF) method, which is a simplified approach, but it is limited owing to the consideration of random waves. Therefore, in industrial practice, the time-domain analysis of random waves is based on the multi degree of freedom (MDOF) method. Although the MDOF method provides high-precision results, its data convergence is sensitive and difficult to apply owing to design complexity. Therefore, a dynamic amplification factor (DAF) estimation formula is developed in this study to express the dynamic response characteristics of random waves through time-domain analysis based on different variables. It is confirmed that the calculation time can be shortened and accuracy enhanced compared to existing MDOF methods. The developed formula will be used in the initial design of WTIVs and similar structures.

• Journal of Korea Entertainment Industry Association
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• v.14 no.7
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• pp.421-427
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• 2020

The aim of this study was to examine the impacts of pre-briefing using structured video simulations in the pre-hospital trauma care simulation-based education on simulation immersion, simulation confidence, and simulation satisfaction. For both the experimental group and the control group, orientations were conducted on the simulation environment. Subsequently, the experimental group watched a video of about 8 minutes, similar to the scenario situation, in which the goal and result of the training were presented. The control group, on the other hand, conducted a classical way of orientation related to the scenario during the same time period. In addition, the experimental group and the control group underwent simulation practice in the same situation for 12 minutes, and debriefing was performed for 40 minutes by the same research assistant. Afterwards, we measured the simulation immersion, confidence, and satisfaction of the participants. Data were analyzed using χ² and independent t-test using the SPSS 22.0 program. It was found that the experimental group that conducted the pre-briefing using video had higher immersion and confidence than the control group. On the other hand, satisfaction was not significantly different between the two groups. The results indicate that pre-briefing using structured video was an effective educational method to increase simulation immersion and simulation confidence.

• Journal of the Korea Institute of Building Construction
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• v.23 no.6
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• pp.693-702
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• 2023

This research explores the potential application of Liquid Red Mud(LRM), a byproduct of industrial processes, in the construction sector. We neutralized LRM(pH 10-12) using nitric acid, aiming to understand its viability in construction applications. The study involved substituting LRM(pH 7-8) in mortar formulations, varying by cement type. We assessed the properties of these mixtures by measuring flow, setting time, and compressive strength. Additionally, X-ray Diffraction(XRD) and Scanning Electron Microscopy(SEM) analyses were conducted to examine the chemical properties. Results indicated a reduction in flow value for LRM and LN(neutralized LRM) compared to the control (Plain ) across different cement types. The setting times(initial and final) for LRM and LN were notably shorter than Plain. In compressive strength tests, LRM replaced with slag cement showed enhanced initial strength, though long-term strength gains were marginal across different cement types. SEM analysis revealed distinct voids in Plain and LN, with LRM exhibiting a fibrous microstructure. XRD patterns in SN(slag neutralized) resembled those in OR(original red mud) and ON(original neutralized), with a notable peak at a 2θ value of 22°. The study concludes that unneutralized LRM, when substituted for slag cement in mortar, yields superior initial strength compared to its neutralized counterpart.

• Journal of Intelligence and Information Systems
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• v.24 no.3
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• pp.67-88
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• 2018

Until recently, as we recognize the significance of sustainable growth and competitiveness of small-and-medium sized enterprises (SMEs), governmental support for tangible resources such as R&D, manpower, funds, etc. has been mainly provided. However, it is also true that the inefficiency of support systems such as underestimated or redundant support has been raised because there exist conflicting policies in terms of appropriateness, effectiveness and efficiency of business support. From the perspective of the government or a company, we believe that due to limited resources of SMEs technology development and capacity enhancement through collaboration with external sources is the basis for creating competitive advantage for companies, and also emphasize value creation activities for it. This is why value chain network analysis is necessary in order to analyze inter-company deal relationships from a series of value chains and visualize results through establishing knowledge ecosystems at the corporate level. There exist Technology Opportunity Discovery (TOD) system that provides information on relevant products or technology status of companies with patents through retrievals over patent, product, or company name, CRETOP and KISLINE which both allow to view company (financial) information and credit information, but there exists no online system that provides a list of similar (competitive) companies based on the analysis of value chain network or information on potential clients or demanders that can have business deals in future. Therefore, we focus on the "Value Chain Network System (VCNS)", a support partner for planning the corporate business strategy developed and managed by KISTI, and investigate the types of embedded network-based analysis modules, databases (D/Bs) to support them, and how to utilize the system efficiently. Further we explore the function of network visualization in intelligent value chain analysis system which becomes the core information to understand industrial structure ystem and to develop a company's new product development. In order for a company to have the competitive superiority over other companies, it is necessary to identify who are the competitors with patents or products currently being produced, and searching for similar companies or competitors by each type of industry is the key to securing competitiveness in the commercialization of the target company. In addition, transaction information, which becomes business activity between companies, plays an important role in providing information regarding potential customers when both parties enter similar fields together. Identifying a competitor at the enterprise or industry level by using a network map based on such inter-company sales information can be implemented as a core module of value chain analysis. The Value Chain Network System (VCNS) combines the concepts of value chain and industrial structure analysis with corporate information simply collected to date, so that it can grasp not only the market competition situation of individual companies but also the value chain relationship of a specific industry. Especially, it can be useful as an information analysis tool at the corporate level such as identification of industry structure, identification of competitor trends, analysis of competitors, locating suppliers (sellers) and demanders (buyers), industry trends by item, finding promising items, finding new entrants, finding core companies and items by value chain, and recognizing the patents with corresponding companies, etc. In addition, based on the objectivity and reliability of the analysis results from transaction deals information and financial data, it is expected that value chain network system will be utilized for various purposes such as information support for business evaluation, R&D decision support and mid-term or short-term demand forecasting, in particular to more than 15,000 member companies in Korea, employees in R&D service sectors government-funded research institutes and public organizations. In order to strengthen business competitiveness of companies, technology, patent and market information have been provided so far mainly by government agencies and private research-and-development service companies. This service has been presented in frames of patent analysis (mainly for rating, quantitative analysis) or market analysis (for market prediction and demand forecasting based on market reports). However, there was a limitation to solving the lack of information, which is one of the difficulties that firms in Korea often face in the stage of commercialization. In particular, it is much more difficult to obtain information about competitors and potential candidates. In this study, the real-time value chain analysis and visualization service module based on the proposed network map and the data in hands is compared with the expected market share, estimated sales volume, contact information (which implies potential suppliers for raw material / parts, and potential demanders for complete products / modules). In future research, we intend to carry out the in-depth research for further investigating the indices of competitive factors through participation of research subjects and newly developing competitive indices for competitors or substitute items, and to additively promoting with data mining techniques and algorithms for improving the performance of VCNS.