• 분석과학
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• 제33권2호
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• pp.98-107
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• 2020

Methamphetamine (MA) is currently the most abused illicit drug in Korea. MA is produced by chemical synthesis, and the final target drug that is produced contains small amounts of the precursor chemicals, intermediates, and by-products. To identify and quantify these trace compounds in MA seizures, a practical and feasible approach for conducting chromatographic fingerprinting with a suite of traditional chemometric methods and recently introduced machine learning approaches was examined. This was achieved using gas chromatography (GC) coupled with a flame ionization detector (FID) and mass spectrometry (MS). Following appropriate examination of all the peaks in 71 samples, 166 impurities were selected as the characteristic components. Unsupervised (principal component analysis (PCA), hierarchical cluster analysis (HCA), and K-means clustering) and supervised (partial least squares-discriminant analysis (PLS-DA), orthogonal partial least squares-discriminant analysis (OPLS-DA), support vector machines (SVM), and deep neural network (DNN) with Keras) chemometric techniques were employed for classifying the 71 MA seizures. The results of the PCA, HCA, K-means clustering, PLS-DA, OPLS-DA, SVM, and DNN methods for quality evaluation were in good agreement. However, the tested MA seizures possessed distinct features, such as chirality, cutting agents, and boiling points. The study indicated that the established qualitative and semi-quantitative methods will be practical and useful analytical tools for characterizing trace compounds in illicit MA seizures. Moreover, they will provide a statistical basis for identifying the synthesis route, sources of supply, trafficking routes, and connections between seizures, which will support drug law enforcement agencies in their effort to eliminate organized MA crime.

• 한국정보컨버전스학회:학술대회논문집
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• 한국정보컨버전스학회 2008년도 International conference on information convergence
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• pp.135-140
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• 2008

Recently in the Mongolian wireless marketplace, many E-commerce companies have been making considerable investments in the technological development of M-commerce, taking competitive advantage of new business possibilities offered by Internet-based wireless technologies. In the Mongolian wireless marketplace, this new mobile environment opens the door for new and exciting market opportunities in mobile services and applications. In the near future, these companies will be looking toward M-commerce services as a supplemental source of revenue in the mobile marketplace. This paper examines the roles of M-commerce in the consumers' in order to promote the consumers' loyalty in the booming M-commerce. This paper contains theory that focuses on the basic concepts of the M-commerce environment, its wireless network technologies, and its applications infrastructure. Upon searching for references to assist us in establishing a market hypothesis, we discovered that few comprehensive studies on consumer perspective and behavior related to M-commerce services actually exist in the literature. In the area of M-commerce, many companies neglect the consumer perspective, concentrating only on technological factors only when formulating their market strategies. And, due to technological blindness, many companies were not able to succeed in end-user E-commerce services. Given that fact, this paper formulates a consumer-centric research model. In order to prove the research model, we chose the survey method which allows for the collection of large amounts of data from a sizeable population in a highly economical way. Through the survey, this paper defines consumer's attitudes towards M-commerce services by identifying potential Business-to-Commerce(B2C) applications and its primary target groups in terms of gender and age, and by investigating whether consumers recognize the value proposition of M-commerce applications and services. As shown in the data analysis and results, this research concludes that M-commerce development in Mongolia is still at its infancy, and that the implementation of M-commerce depends not only on technological progress, but also on consumer attitudes and their willingness to adopt M-commerce services. As well, other complex cross-cultural factors-socially, economically, culturally, et cetera-enter strongly into the equation.

• 대한한의학회지
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• 제20권1호
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• pp.151-160
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• 1999

Nitric oxide(NO) is synthesized via the oxidation of L-arginine by a family of nitric oxide synthases(NOS), which are either constitutive(cNOS) or inducible(iNOS). The induction of iNOS in tissues can lead to the sustained production of high concentrations of NO which may exert pro-inflammatory effects including vasodilation. edema, cyototoxicity, and its activity can be mediated by various pro-inflammatory cytokine, including interferon ${\gamma}(INF-{\gamma})$. tumor necrosis factor, IL- 1 and IL-6. The enzyme, iNOS, became a new target for pharmacologcal research with the aim to find new substances for the treatment of chronic inflammatory disorders. Murine macrophages produce large amounts of NO when activated with $TFN-{\gamma}$ plus LPS. The murine macrophage-like cell line, RAW 264.7, is a suitable cell model on which to perform vitro studies regarding the iNOS system. Semen jugrandis is a fatty walnut seed found in Korea. The walnut have been used in foik medicine to improve virility, to relieved asthma, and to relieve constipation. Sesquiterpenelactones were isolated from this plant. In the course of screening for NO inhibitory activity from medicnial plants, the aqueous extract of this plant was found to have a significant activity. The result are summarized as followings. 1. The viability of cells incubated in the presence of semen jugrandis increased mare than non incubated cells. 2. Semen jugrandis suppressed the production of NO in tissues dependent on density. 3. Semen jugrandis suppressed the induction of iNOS in tissues dependent on density can lead to reduced production of NO. 4. Semen jugrandis suppressed the production of superoxide in tissue depend on density. According to the above mentioned results, semen jugrandis could be applied production of NO and superoxide can lead to reduction of chronic inflammatary. And as a depence matter come into a virus of microbe and tumor cells.

• 수산해양교육연구
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• 제10권2호
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• pp.162-183
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• 1998

The fisheries resources control system in the Fisheries Act of Korea is introducing technical management method and input control method that controls fishing effort. Fishing effort control system of Korea aiming at realizing the maximum sustainable yield does not regulating the limitation of fishing quota and the limitation of fisheries object target fish. Therefore fishing operators who have fishing permit can use fishery resources without any restriction of fishing quota. But there are no rules that can controlling capacity of productivity of fishing by developing of fishing technic and fishing gear. For those reasons, productivity of fishing is superior to reproductivity of fisheries resources. Therefore, the Fisheries Act of Korea rearranges a legal basis for an introduction of fisheries resources management system by TAC, but the contents to be possible for a legal guarantee is not included and it is exceedingly defective as abstract and institutional devices. And that the affairs to be required for an enforcement of the said regime was placed in an administrative mandatory legislation and the danger to be degenerated is high in accordance with the bureaucratic self-righteous and/or the coercion of group's interest concerned and accordingly its substitute legislation system is keenly required. TAC system that is going to be introduced in our country is expected to enforce the Olympic fishing method and the individual quota method in parallel. This method is not certainly proper, because it occurs to overcapitalize and to compete fishing amounts between fishery operators. So as to prevent overcapitalization and fishing competition between fishery operators, and the exhaustion of coastal fisheries resources, individual transferable quota system should be introduced in Korean sea. Accordingly this thesis has attempted to constitute a view to improving problems of the traditional fisheries resources control system and introducing TAC fisheries resources control system.

• 한국태양에너지학회 논문집
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• 제34권1호
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• pp.81-90
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• 2014

The Jeju-Korea power system is a small-sized network with a system demand ranging from a autumn minimum of 350MW to a summer peak of 716MW. Because Jeju island is well exposed to north-east winds with high speed, applications to connect to Jeju power system are flooded. Considering physical/environmental constraints, Jeju Self-governing Province has also target for the wind power capacity of 1,350MW by 2020. It amounts to two or three times of Jeju average-demand power and wind power limit capacity announced by Korea Power Exchange (KPX) company. Wind farm connection agreements will be signed to maximize utilization of wind resource. In spite of submarine cable HVDC connected to Korea mainland, Jeju power system is independently operated by frequency and reserve control. This study reevaluates wind power limit based on the KPX criteria from 2016 to 2020. First of all wind power generation limit are affected by off-peak demand in Jeju power system. Also the possibility capacity rate of charging wind power output is evaluated by using energy storage system (ESS). As a result, in case of using 110MWh ESS, wind power limit increases 33~55MW(30~50% of ESS), wind power constraint energy decreases from 68,539MWh to 50,301MWh and wind farm capacity factor increases from 25.9 to 26.1% in 2020.

• 한국표면공학회지
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• 제44권2호
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• pp.60-67
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• 2011

Ternary B-C-N coatings were deposited on Si(100) wafer substrate from $B_4C$ target by RF magnetron sputtering technique in $Ar+N_2+CH_4$ gas mixture. In this work, the effect of reactant gas ratio, $CH_4/(N_2+CH_4)$ on the composition, kinds and amounts of bonding states comprising B-C-N coatings were investigated using two different bias power sources of continuous and unipolar DCs. In addition, the tribological properties of coatings were studied with the composition and bonding state of coating. It was found that the substrate bias power had an effect on chemical composition, and all of the obtained coatings were nearly amorphous. Main bonding states of coatings were revealed from FTIR analyses to be h-BN, C-C, C-N, and B-C. The amount of C-C bonging mainly increased with increase of the reactant gas ratio. From our studies, both C-C and h-BN bonding states improved the tribological properties but B-C one was found to be harmful on those. The best coating from tribological points of view was found to be $BC_{1.9}N_{2.3}$ composition.

• 콘크리트학회논문집
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• 제14권3호
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• pp.365-372
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• 2002

본 연구는 700kgf/$\textrm{cm}^2$ 고강도 콘크리트에서 횡보강근 형태, 체적비 그리고 횡보강근 항복강도에 따른 고강도 콘크리트기둥의 거동을 규명하기 위한 실험연구이다. 기둥은 중심축내력의 30%에 해당하는 일정축력과 수평방향의 반복 휨모멘트를 받는다. 본 연구에서 사용된 변수는 횡보강근 체적비(Ps=1.58, 2.25%), 횡보강근 형태(hoop-type, cross-type, diagonal-type) 그리고 횡보강근 항복강도(fy=5,600, 7,950 kgf/$\textrm{cm}^2$)이다. 실험결과로 모든 기둥의 휨강도는 현행규준의 등가응력블럭에 근거하여 산정된 휨강도보다 낮게 나타났다. 횡보강근을 ACI 규준 요구량보다 42%증가시킨 기둥 시험체는 연성적인 거동을 보였다. 그리고, 본 연구에서 적용한 축력비 0.3 P/PO하에서 고강도급 횡보강근을 사용한 시험체의 연성이 저강도급 횡보강근을 사용한 시험체의 경우보다 같거나 다소 큰 경향을 보이고 있었다.

• Journal of Dairy Science and Biotechnology
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• 제34권3호
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• pp.145-155
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• 2016

Cow's milk and dairy products are elements of the human diet that could play an important role in improving human health. The macronutrients and micronutrients found in milk could supply the nutrients required to maintain human health. Among them, milk-derived bioactive peptides have been identified as potential ingredients found in health promoting functional foods. These bioactive peptides target diet-related chronic diseases, particularly non-communicable ones such as cardiovascular disease, diabetes and obesity. Additionally probiotics such as lactic acid bacteria (LAB) are can be considered live microorganisms that confer health benefits for the host-, when administered in adequate amounts. Further, the calcium, vitamin D, and protein content of milk and dairy products could play a role in proving bone health. The effect of milk and calcium on bone mineral density could prevent against fracture, osteoporosis and rickets. Furthermore, milk and dairy products also contain which factors that, which protect against dental caries (anti-cariogenic properties). This paper reviews the various nutritional functions of milk and dairy products in improving human health.

• 인터넷정보학회논문지
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• 제5권2호
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• pp.75-84
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• 2004

지오캐스팅(geocasting)이란 멀티캐스팅의 특별한 한 종류로서, 어떤 특정한 지역(지오캐스트 영역이라 함)에 있는 모든 노드들에게 데이터를 전송하는 통신형태를 말하며, location-based multicasting(LBM) 이라고 부르기도 한다(1). Ad-hoc 네트워크는 중앙 집중화된 관리나 표준화된 지원 서비스 없이 배터리를 에너지원으로 사용하는 휴대용 기기들이 동적으로 연결되어 구성되는 임시적인 망이다. 따라서, 제한된 에너지 자원을 효율적으로 관리하는 것은 네트워크 활동시간(lifetime)을 최대화하기 위한 중요한 문제가 된다. 본 논문에서는 Ad-hoc 네트워크 환경에서 라우팅 설정시 에너지 값을 고려하여 중간 노드를 선택하는 LBPA(Location-Based Power Aware) 지오캐스팅 알고리즘을 제안한다. 전송 에너지를 균형있게 소비하여 각 이동 호스트의 잔여 에너지의 비율을 일정하게 유지시키는 방법으로 네트워크 활동시간 측면에서 볼 때 기존의 LBM 알고리즘보다 평균적으로 49%, 더 좋은 결과를 실험을 통하여 보여주었다.

• ALGAE
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• 제33권4호
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• pp.341-349
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• 2018

Sargassum horneri is edible brown seaweed abundant along the coasts of Jeju Island, South Korea. In addition to the native S. horneri population, a large amount of S. horneri has been found to invade Jeju Island from the east coast of China. Thus, S. horneri of both Korea (SK) and China (SC) strains now inhabits along with the shore of Jeju Island and have become a threat to the coastal biodiversity. However, they could be used in obtaining functional ingredients for industrial level applications provided an optimized cost effective strategy. In the present study, we compared SK and SC strains for the extraction efficiency, components, antioxidant, and anti-inflammatory properties of 80% methanolic extracts and their partially purified fractions. According to the results, two strains indicated similar bioactive properties such as DPPH and alkyl radical scavenging activity as well as anti-inflammatory activities on lipopolysaccharide-stimulated RAW 264.7 cells. The yield of 80% methanol extract from SC was higher than SK. However, the yields of the ethyl acetate and chloroform fractions from SK were higher than those of SC strain. The major peaks in the high-performance liquid chromatography chromatograms, which was identified as Apo-9 fucoxanthinone, indicated that both methanolic extracts of SK and SC contains major target peaks but with different amounts. This study might be useful for developing functional materials from SC and SK in future.