• Economic and Environmental Geology
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• v.28 no.4
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• pp.337-350
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• 1995

The Hwacheon-ri mineralized area is located within the Cretaceous Gyeongsang Basin of the Korean peninsula. The mineralized area includes the Hwacheon, Daeweon, Kuryong and Cheongryong mines. Each of these mines occurs along copper-bearing hydrothermal quartz veins that crosscut late Cretaceous volcanic rocks, although some disseminated ores in host rocks also exist locally. Mineralization can be separated into three distinct stages (I, II, and III) which developed along preexisting fracture zones. Stage I is ore-bearing, whereas stages II and III are barren. The main phase of ore mineralization, stage I, can be classified into three substages (Ia, Ib and Ic) based on ore mineral assemblages and textures. Substage Ia is characterized by pyrite-arsenopyrite-molybdenite-pyrrhotite assemblage and is most common at the Hwacheon deposit. Substage Ib is represented by main precipitation of Cu, Zn, and Pb minerals. Substage Ic is characteristic of hematite occurrence and is shown only at the Kuryong and Cheongryong deposits. Some differences in the ore mineralization at each mine in the area suggest that the evolution of hydrothermal fluids in the area varied in space (both vertically and horizontally) with respect to igneous rocks relating the ore mineralization. Fluid inclusion data show that stage I ore mineralization mainly occurred at temperatures between ${\approx}350^{\circ}$ and ${\approx}200^{\circ}C$ from fluids with salinities between 9.2 and 0.5 wt.% eq. NaCl. In the waning period of substage Ia, the high temperature and salinity fluid gave way to progressively cooler, more dilute fluids of later substage Ib and Ic (down to $200^{\circ}C$, 0 wt.% NaCl). There is a systematic decrease in the calculated ${\delta}^{18}O_{H2O}$ values with paragenetic time in the Hwacheon-ri hydrothermal system from values of ${\approx}2.7$‰ for substage Ia, through ${\approx}-2.8$‰ for substage Ib, to ${\approx}-9.9$‰ for substage Ic. The ${\delta}D$ values of fluid inclusion water also decrease with decreasing temperature (except for the Daeweon deposit) from -62‰ (substage Ia) to -80‰ (substage Ic and stage III). These trends are interpreted to indicate the progressive cooler, more oxidizing unexchanged meteoric water inundation of an initial hydrothermal system which is composed of highly exchanged meteoric water. Equilibrium thermodynamic interpretation of the mineral assemblages with the variation in amounts of chalcopyrite through the paragenetic time, and the evolution of the Hwacheon-ri hydrothermal fluids indicate that the solubility of copper chloride complexes in the hydrothermal system was mainly controlled by the variation of temperature and $fo_2$ conditions.

• Journal of Life Science
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• v.23 no.9
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• pp.1126-1132
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• 2013

Cytochrome P450 2J2 (CYP2J2) is an enzyme mainly found in human extrahepatic tissues, with predominant expression in the cardiovascular system. CYP2J2 plays important roles in the metabolism of endogenous metabolites and therapeutic drugs, such as arachidonic acid, astemizole, ebastine, and terfenadine. CYP2J2 is also overexpressed in human cancer tissues and cancer cell lines and may represent a potential target for therapy of human cancers. In this study, 10 natural products obtained from plants and microorganisms were screened as potential CYP2J2 inhibitors. Among them, thelephoric acid showed strong inhibition of astemizole O-demethylation activity ($IC_{50}=3.23{\mu}M$) in a dose-dependent manner. Evaluation of the substrate dependency of the inhibitory activity of thelephoric acid showed that it strongly inhibited CYP2J2-mediated ebastine hydroxylation ($IC_{50}=5.32{\mu}M$) and terfenadine hydroxylation ($IC_{50}=3.27{\mu}M$) in a substrate nondependent manner. The present data suggest that this compound might be a potential candidate for further evaluation for anticancer activity.

• Journal of Microbiology and Biotechnology
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• v.20 no.6
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• pp.988-994
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• 2010

The EtOAc fraction of Lespedeza cyrtobotrya showed mushroom tyrosinase inhibitory and radical scavenging activities. Four active compounds were isolated based on Sephadex LH-20 chromatography and HPLC, and the structures were elucidated, on the basis of their LC-MS and NMR spectral data, as 2-(2,4-dihydroxyphenyl)-6-hydroxybenzofuran (1), eriodictyol-7-O-glucopyranoside (2), haginin A (3), and dalbergioidin (4), respectively. Compound (1) showed mushroom tyrosinase inhibitory activity with an $IC_{50}$ value of $5.2\;{\mu}M$ and acted as a competitive inhibitor. Furthermore, $37.3\;{\mu}M$ of compound 1 reduced 50% of the melanin content on human melanoma (MNT-1) cells. The radical scavenging activities of compounds 1, 2, 3, and 4 were shown to have $IC_{50}$ values of 11.0, 24.5, 9.0, and $36.5\;{\mu}M$, respectively, in an ABTS system and $IC_{50}$ values of 42.7, 36.0, 37.7, and $61.7\;{\mu}M$, respectively, in a DPPH system. The mushroom tyrosinase inhibitory activity of the EtOAc fraction of Lespedeza cyrtobotrya was contributed by compounds 1, 3, and 4, and its radical scavenging activity was contributed by compounds 1-4.

• Journal of Environmental Science International
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• v.21 no.11
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• pp.1321-1331
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• 2012

To date, carbon and nitrogen co-doped photocatalysts (CN-$TiO_2$) for environmental application focused mainly on the aqueous phase to investigate the decomposition of water pollutants. Accordingly, the present study explored the photocatalytic performance of CN-$TiO_2$ photocatalysts for the purification of indoor-level gas-phase aromatic species under different operational conditions. The characteristics of prepared photocatalysts were investigated using X-ray diffraction, scanning emission microscope, diffuse reflectance UV-VIS-NIR analysis, and Fourier transform infrared (FTIR) analysis. In most cases, the decomposition efficiency for the target compounds exhibited a decreasing trend as input concentration (IC) increased. Specifically, the average decomposition efficiencies for benzene, toluene, ethyl benzene, and xylene (BTEX) over a 3-h process decreased from 29% to close to zero, 80 to 5%, 95 to 19%, and 99 to 32%, respectively, as the IC increased from 0.1 to 2.0 ppm. The decomposition efficiencies obtained from the CN-$TiO_2$ photocatalytic system were higher than those of the $TiO_2$ system. As relative humidity (RH) increased from 20 to 95%, the decomposition efficiencies for BTEX decreased from 39 to 5%, 97 to 59%, 100 to 87%, and 100 to 92%, respectively. In addition, as the stream flow rates (SFRs) decreased from 3.0 to 1.0 L $min^{-1}$, the average efficiencies for BTEX increased from 0 to 58%, 63 to 100%, 69 to 100%, and 68 to 100%, respectively. Taken together, these findings suggest that three (IC, RH, and SFR) should be considered for better BTEX decomposition efficiencies when applying CN-$TiO_2$ photocatalytic technology to purification of indoor air BTEX.

• Convergence Security Journal
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• v.16 no.5
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• pp.33-40
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• 2016

Credit card is means of payment used like cash in terms of function and its users have increased consistently. With development of Internet and electronic commerce a role as payment method of credit card has been growing. But as the risk which results from centralized information and online increases, credit card fraud is also growing. Card theft and loss are decreasing due to countermeasure of card companies and financial supervisory authorities, while card forge and identity theft are increasing. Recently because of frequent personal information leakage and deregulation of financial security following easy-to-use payment enforcement, customer's anxiety about card fraud is growing. And the increase of card fraud lowers trust on credit system as well as causes social costs. In this paper, the security problems of card operating system are addressed in depth and the measures such as immediate switch to IC card terminals, introduction of new security technology, supervision reinforcement of the authorities are proposed.

• Journal of Environmental Science International
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• v.18 no.11
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• pp.1215-1224
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• 2009

This study evaluated the applicability of visible-light-driven N- and S-doped titanium dioxide($TiO_2$) for the control of low-level dimethyl sulfide(DMS) and dimethyl disulfide(DMDS). In addition, a photocatalytic unit(PU)-adsorption hybrid was evaluated in order to examine the removal of DMS and DMDS which exited the PU and a gaseous photocatalytic byproduct($SO_2$) which was generated during the photocatalytic processes. Fourier-Tranform-Infrared(FTIR) spectrum exhibited different surface characteristics among the three-types of catalysts. For the N- and S-doped $TiO_2$ powders, a shift of the absorbance spectrum towards the visible-light region was observed. The absorption edge for both the N- and S-doped $TiO_2$ was shifted to $\lambda$ 720 nm. The N-doped $TiO_2$ was superior to the S-doped $TiO_2$ in regards to DMS degradation. Under low input concentration(IC) conditions(0.039 and 0.027 ppm for DMS and DMDS, respectively), the N-doped $TiO_2$ revealed a high DMS removal efficiency(above 95%), but a gradual decreasing removal efficiency under high IC conditions(7.8 and 5.4 ppm for DMS and DMDS, respectively). Although the hybrid system exhibited a superior characteristic to PU alone regarding the removal efficiencies of both DMS and DMDS, this capability decreased during the course of a photocatalytic process under the high IC conditions. The present study identified the generation of sulfate ion on the catalyst surface and sulfur dioxide(maximum concentrations of 0.0019 and 0.0074 ppm for the photocatalytic processes of DMS and DMDS, respectively) in effluent gas of PU. However, this generation of $TiO_2$ would be an insignificant addition to indoor air quality levels.

• Journal of the Korea Safety Management & Science
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• v.16 no.3
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• pp.451-469
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• 2014

The purpose of this study is to implement and develop the integrated Economic Value Added (EVA) and Time-Driven Activity-Based Costing (TDABC) model to seek both improvement of Net Operating Profit Less Adjusted Tax (NOPLAT) and reduction of Capital Charge (CC). Net Operating Profit Less Adjusted Tax (NOPLAT) can be maximized by reducing the indirect cost of an unused resource capacity increased by Cost Capacity Ratio (CCR) of TDABC. On the other hand, Capital Charge (CC) can be minimized by improving the efficiency of Invested Capital (IC) considered by Weighted Average Cost of Capital (WACC) of EVA. In addition, the integrated system of TDABC using Balance Scorecard (BSC) and EVA is developed by linking between the lagging indicators and the three leading indicators. The three leading indicators include customer, internal process and growth and learning perspectives whereas the lagging indicator includes NOPLAT and CC in terms of financial perspective. When the Critical Success Factor (CSF) of BSC is cascading as a cause and an effect relationship, time driver of TDABC and capital driver of EVA can be used efficiently as Key Performance Indicator (KPI) of BSC. For a better understanding of the proposed EVA/TDABC model and BSC/EVA/TDABC model, numerical examples are derived from this paper. From the proposed model, the time driver of TDABC and the capital driver of EVA are known to lessen indirect cost from comprehensive income statement when increasing the efficiency of operating IC from the statement of financial position with unified KPI cascading of aligned BSC CSFs.

• International Area Studies Review
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• v.14 no.3
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• pp.178-204
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• 2010

This study analyzes the effects Korea's grant aid to 53 African countries, focusing on its impacts on improving HDI (Human Development Index) of each recipient country, through panel data analysis. According to the OLS panel analysis, Korea's grant aid on information and communication (IC) sector showed positive and significant correlation with HDI, but aid on administrative system and environment showed negative correlation with HDI. Also, according to the fixed effect panel analysis, aid on IC sector showed positive correlation with HDI, but aid on administrative system showed negative correlation with HDI. In particular, effects of aid was different across the region. In North African region, aid on health improved HDI. However, in Sub-Saharan African region, aid on IC was more effective in improving HDI. This results imply that grand aid on Africa needs to be coordinated strategically across regions and sectors. This paper is meaningful in providing ways that can be mutually beneficial both to donor and recipient countries of grant aid.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.190-192
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• 1998

이동에이전트를 위한 이동객체(mobile agent)와 이를 지원해주는 이동객체서버(mobile object system)를 설계하고 이러한 요소들을 제어하고 관리하는 이동객체 시스템(mobile object system)을 Java로 구현한다. 또, 시스템 내의 이동객체를 비롯한 모든 객체들간의 객체 요청(object request)을 유연하게 중계하고 이들간의 통신을 담당하는 ORB (Object Request Broker)를 TCP/IC상에서 Java 로 구현하고 이동 에이젼트 시스템을 쉽게 구측할수 있는 앱스트랙션(abstraction)과 API를 제공한다. 이 시스템은 네이밍 서비스(naning service)와 푸쉬형 이벤트 서비스(push-event service)등을 기본적으로 지원한다.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.4
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• pp.652-657
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• 1987

This paper describes an application of CMOS Gate Array Integrated Cricuits to the implementation of three functional units: A Multiplexer, Time Switch, and Demultiplexer in the Switching Network and Digital Line Concentrator of TDX-1 system, which is a fully digital time division electronic switching system in Korea. The application of CMOS Gate Array Integrated Circuits significantly improves the overall system performance in terms of power consumption, cost, size, reliability, and timing margin, etc.