• 대한화장품학회지
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• 제42권3호
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• pp.269-278
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• 2016

천연자원으로부터 항노화 화장품 신소재를 탐색하던 중, 국내 자생버섯의 일종인 붉은싸리버섯 자실체 추출물이 항산화 활성과 인체 호중구 엘라스타제 저해활성이 우수함을 확인하고 일련의 연구를 수행하였다. 붉은싸리버섯 추출물의 DPPH 라디칼 소거활성은 붉은싸리버섯 추출물 $500{\mu}g/mL$ 처리시 $117.0{\mu}g/mL$ (ascorbic acid 환산값)의 매우 우수한 소거활성을 나타냈다. Peroxy 라디칼 소거활성을 oxygen radical absorbance capacity (ORAC) assay 를 통하여 측정한 결과 붉은싸리버섯 추출물 1, 10, $20{\mu}g/mL$ 처리 시, 각각 0.8, 5.2, 7.8 $ORAC_{Roo}$ (trolox equivalents, $1{\mu}M$)로 농도 의존적으로 높은 소거활성을 나타냈다. 뿐만아니라 cellular antioxidant capacity를 DCF fluorescence intensity (% of control)로 조사한 결과에서도 붉은싸리버섯 추출물 $20{\mu}g/mL$ 처리시 약 30% 이상 높은 항산화 활성을 나타냈다. Human neutrophil elastase 저해활성은 농도 의존적으로 저해활성을 나타냈으며 특히 에탄올 추출분획에서 $ED_{50}$ 값은 $42.9{\mu}g/mL$이었다. 붉은싸리버섯 추출물은 Bacillus subtilis (B. subtilis), Escherichia coli (E. coli), Candida albicans (C. albicans), Aspergillus oryzae (A. oryzae) 균주 모두에서 항균활성은 나타나지 않았다. 또한 염증성 cytokine인 interleukin-10 및 interferon-${\gamma}$ (IFN-${\gamma}$)의 생산 또는 분비 조절에는 영향을 미치지 않았다. 이상의 결과로 붉은싸리버섯 추출물은 항산화활성과 elastase 저해활성을 우수하여 피부에 자극이 없는 항노화 화장품 조성물로 유용하게 사용될 수 있음을 확인하였다.

• 한국정보과학회논문지:정보통신
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• 제29권3호
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• pp.299-313
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• 2002

이동 통신 수요의 급격한 증가와 멀티미디어 서비스에 대한 요구에 의해 기존의 셀룰러 시스템은 용량 부족 및 QoS 처리에 있어서 한계에 부딪히게 되었다. 따라서 사용자들이 요구하는 QoS를 만족시켜줌과 동시에 최대한 많은 사용자를 수용하기 위해 계층셀 구조가 제안되었다. IMT-2000에서는 셀구성 방안으로 계층셀 구조를 채택하였는데, 그에 따라 복잡한 중첩 구조를 간단하면서도 효율적으로 이용할 수 있는 호 처리 알고리즘의 필요성이 대두되었다. 본 연구에서는 기존에 제안된 복합 호 처리 방식에서 한 걸음 나아가 이동 속도와 대역폭을 고려한 호 처리 알고리즘을 제안하였다. 제안한 알고리즘에서는 버퍼와 가드 채널을 이용하여 호의 이동 속도와 대역폭을 고려하여 기존의 방식보다 효율성을 높일 수 있도록 하였다. 또한 대역폭과 이동 속도를 고려하여 호들을 분배하여 처리함으로써 사용자의 QoS를 만족시켜주고 핸드오버율을 줄이고자 하였다. 제안한 알고리즘의 성능을 평가하기 위해서 본 논문에서는 계층 셀룰러 시스템을 구성하고 다양한 트래픽을 생성하여 시뮬레이션을 수행하였다. 블로킹률, 드로핑률, 채널 활용률, 계층간 핸드오버 수 등 다양한 파라미터를 토대고 기존의 방식과 제안한 방식을 비교해봄으로써 성능 향상을 입증하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제3권4호
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• pp.385-398
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• 2009

This paper aims to find a suitable solution to joint allocation of sub-channel and transmit power for multiple users in an IEEE 802.16e OFDMA/TDD cellular system. We propose the FASA (Fairness insured Aggressive Sub-channel Allocation) algorithm, which is a dynamic channel allocation algorithm that considers all of the users' channel state information conditionally in order to maximize throughput while taking into account fairness. A dynamic power allocation algorithm, i.e., an improved CHC algorithm, is also proposed in combination with the FASA algorithm. It collects the extra downlink transmit power and re-allocates it to other potential users. Simulation results show that the joint allocation scheme with the improved CHC power allocation algorithm provides an additional increase of sector throughput while simultaneously enhancing fairness. Four frames of time delay for CQI feedback and scheduling are considered. Furthermore, by addressing the difference between uplink and downlink scheduling in an IEEE 802.16e OFDMA TDD system, we can employ the uplink channel information directly via channel sounding, resulting in more accurate uplink dynamic resource allocation.

• 약학회지
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• 제46권6호
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• pp.466-471
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• 2002

Oxidative stress is considered to be associated with many diseases, such as inflammatory and cardiovascular diseases, aging and cancer. An important etiological mechanism of these diseases may be a causal relationship between the presence of oxidants and the generation of lipid hydroperoxides derived from enzymatic reactions or xenobiotic metabolism. The hydroperoxides can be decomposed to alkoxy- (ROㆍ) and peroxy- (ROOㆍ) free radicals that can oxidize other cell components, resulting in changes in enzyme activity or the generation of mediators, which can cause further cell damage. The aim of this study was to evaluate the ability of aqueous extract from the roots of Platycodon grandiflorum A. DC (Campanulaceae), Changkil (CK), to affect cellular response in primary cultures of rat hepatocytes to t-butyl hydroperoxide (t-BHP) induced oxidative stress and hepatotoxicity. CK-treated cells showed an increased resistance to oxidative challenge, as revealed by a higher percent of survival capacity in respect to control cells. CK reduced t-BHP-enhanced lipid peroxidation measured as production of malondialdehyde and enhanced intracellular reduced glutathione depletion by t-BHP. Furthermore, CK protected from the t-BHP-induced intracellular generation of reactive oxygen species assessed by monitoring dichlorodihydrofluorescein fluorescence. It can be concluded that CK exerts an antioxidant action inside the cell, responsible for the observed modulation of the cellular response to oxidative challenge, and CK have a marked antioxidative and hepatoprotective potency.

• 산업경영시스템학회지
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• 제28권2호
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• pp.94-100
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• 2005

This paper presents the application of integrated mathematical programming approach for the design of cellular manufacturing. The proposed approach is carried out in two phases The first phase concerning exceptional elements(EEs) in cell formation and the second phase facilities layout design. This paper considers the total costs of three important costs for (1) intercellular transfer (2) machine duplication and (3) subcontracting. One of Important issue is the calculation of the number of machines considering the maximum utilization of machines and the available capacity of a machines that can be transferred between cells. Facilities layout design is considered to reflect the real field data taking in to account the operational sequence of the parts to be manufactured. The model is formulated as mixed integer programming that is employed to find the optimal solution.

• 대한예방한의학회지
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• 제11권1호
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• pp.1-8
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• 2007

Curcumin and its analogues(Tetrahydrocurcumin THC, demethoxycurcumin ; BDMC and dimethoxycurcumin DiMC) were compared for their ability to inhibit the growth of human leukemia HL-60 cells. The growth of HL-60 cells was inhibited by curcumin, DeMC and DiMC, but not by THC lacking ${\alpha},{\beta}-unsaturated$ carbonyl groups thus suggesting that ${\alpha},{\beta}-unsaturated$ carbonyl groups are crucial for antiproliferative activity. The order of antiproliferative activity was DiMC, curcumin and BDMC indicating that the number of methoxy groups on the aromatic rings of the active compounds plays an important role in enhancing anti-proliferating activity. In comparison with cellular uptake of the active compounds, uptake capacity was found to be highest with DiMC, followed by curcumin and BDMC. Therefore, it is most likely that the differential antiproliferative activities of DiMC, curcumin and BDMC are associated with their capacities of cellular uptake resulting in building up of enough concentration inside the cells.

• 한국통신학회논문지
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• 제38A권12호
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• pp.1117-1124
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• 2013

최근 무선트래픽 수요가 폭발적으로 증가하면서 셀룰라 무선망에서 이를 효율적으로 지원하기 위한 스몰셀 연구가 활발히 수행중이다. 본 논문은 스몰셀 구현의 가장 큰 걸림돌인 다중셀 간섭을 효율적으로 해결하기 위한 간섭상쇄 기법에 대해 연구하였다. 각 사용자의 메시지가 기지국 혹은 릴레이를 통하여 전달되는 경우, 무선채널의 시변특성을 이용한 간섭상쇄 기법을 제안하였다. Amplify-and-forward (AF) 에 기반한 기존 접근방식은 잡음증폭 특성으로 인하여 신호대잡음비가 낮은 영역에서는 심한 성능열화를 보였다. 본 논문은 최근 개발된 compute-and-forward (CF) 에 기반한 간섭상쇄를 제안하여 이러한 문제를 해결하고 신호대잡음비가 작은 영역에서 전송율을 크게 개선하였다.

• Journal of Communications and Networks
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• 제10권2호
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• pp.118-126
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• 2008

The use of beamforming is effective for users in limited power environments. However, when it is applied to the downlink of a cellular system with universal frequency reuse, users near the sector boundary may experience significant interference from more than one sector. The use of a minimum mean square error (MMSE)-type receiver may not sufficiently cancel out the interference unless a sufficient number of receive antennas are used. In this paper, we consider the use of inter-sector beamforming that cooperates with a neighboring sector in the same cell to mitigate this interference problem in time-division duplex (TDD) environments. The proposed scheme can avoid interference from an adjacent sector in the same cell, while enhancing the transmit array gain by using the TDD reciprocity. The performance of the proposed scheme is analyzed in terms of the output signal-to-interference-plus-noise power ratio (SINR) and the output capacity when applied to an MMSE-type receiver. The beamforming mode can be analytically switched between the inter-sector and the single-sector mode based on the long-term channel information. Finally, the effectiveness of the proposed scheme is verified by computer simulation.

• 한방안이비인후피부과학회지
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• 제4권1호
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• pp.23-42
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• 1991

This study were done to know the effects of Dangkiyeumja on the in vivo and in vitro immune responses of mice. The recipes of Dangkiyeumja used in this study enhanced such, cellular functions of immunocytes as phagocytic capacity of macrophages, rossett-eforming abilities of splenocytes and metabolic activities of lymphocytes, However, the same recipes decreased the formation of such reactive oxygen intermediates(ROI) as superoxide and hydrogenperoxide from the macrophages. The effects of the same recipes on the in vim immune responses was suppressive on the cellular immune response(CIR)measured by delayed-type hypersensitivity against dinitrofluorobenzene and mildly enhancing for the humoral immune response measured by antibody production against sheep red blood cells. The results of this study could be summarized as follow: 1. Administration of Dangkiyeumja enhanced the phagocytic activity of the murine macrophage. 2. Administration of Dangkiyeumja decreased the formation of ROI in the murine macrophage 3. Administration of Dangkiyeumja increased the number of the splenic rotte forming cells in the mouse. 4. Administration of DangKiyeumja did not effect the antibody production against sheep red blood cells. 5. Administration of Dangkiyeumja depressed the delayed-type hypersenitivity against dinitrofluoro benzene in the mouse. The result of this study suggest that Dangkiyeumja could ameliorate the hypersensitivity reactions by reducing the formation of ROI and decreasing the CIR without affecting the other functions of immunocytes.

• 한국경영과학회지
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• 제23권3호
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• pp.135-151
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• 1998

The demand of large capacity in coming cellular systems makes inevitable the deployment of small cells, rendering more frequent handoff occurrences of calls than in the conventional system. The key issue is then how effectively to reduce the chance of unsuccessful handoffs, since the handoff failure is less desirable than that of a new call attempt. In this study, we consider the control policies which give priority to handoff calls by limiting channel assignment for the originating new calls, and allow queueing the new calls which are rejected at their first attempts. On this system. we propose the problem of finding an optimal call control strategy which optimizes the objective function value, while satisfying the requirements on the handoff/new call blocking probabilities and the new call delay. The objective function takes the most general form to include such well-known performance measures as the weighted average carried traffic and the handoff call blocking probability. The problem is formulated into two different linear programming (LP) models. One is based on the direct employment of steady state equations, and the other uses the theory of semi-Markov decision process. Two LP formulations are competitive each other, having its own strength in the numbers of variables and constraints. Extensive experiments are also conducted to show which call control strategy is optimal under various system environments having different objective functions and traffic patterns.