• 대한화장품학회지
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• 제39권4호
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• pp.329-335
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• 2013

본 연구에서는 기질 화합물로써 일련의 4-hydroxybenzyl alchol (4-HBA) 유도체들의 치환기($R_1$ 및 $R_2$) 변화에 따른 tyrosinase 활성저해에 관한 3차원적인 구조-활성 상관관계(3D-QSARs) 모델을 유도하고 정량적으로 검토하였다. 그 결과, 입체장(S), 정전기장(E), 소수성장(Hy), 수소결합 받게장(HA) 및 수소결합 주게장(HD)의 조합조건에서 통계적으로 양호한 CoMSIA FF 모델(상관성; $r^2$ = 0.858 및 예측성; $q^2$ = 0.951)을 유도하였다. 등고도 분석결과에 의하면 기질분자의 $R_2$-치환기는 입체적으로 작고 음전하를 띄며, 소수성이면서 수소결합 주게장을 선호하지 않는 치환기가 올수록 tyrosinase 활성저해 작용이 용이하다. 그리고 $R_1$-치환기는 수소결합 주게장을 선호하는 치환기 이어서 $R_1$-치환체가 용이하게 탈 양성자화가 일어나야 tyrosinase 활성저해 작용을 용이하게 할 것이라고 예상되며, 이를 위해서는 $R_1$-치환기가 비 치환체(H)이어야 될 것으로 예상되었다.

• Journal of Ginseng Research
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• 제42권4호
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• pp.419-428
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• 2018

Background: Despite the large number of studies on ginseng, pharmacological activities of ginseng seed oil (GSO) have not been established. GSO is rich in unsaturated fatty acids, mostly oleic and linoleic acids. Unsaturated fatty acids are known to exert a therapeutic effect in nonalcoholic fatty liver disease (NAFLD). In this study, we investigated the protective effect and underlying mechanisms of GSO against NAFLD using in vitro and in vivo models. Methods: In vitro lipid accumulation was induced by free fatty acid mixture in HepG2 cells and by 3 wk of high fat diet (HFD)-feeding in Sprague-Dawley rats prior to hepatocyte isolation. The effects of GSO against diet-induced hepatic steatosis were further examined in C57BL/6J mice fed a HFD for 12 wk. Results: Oil Red O staining and intracellular triglyceride levels showed marked accumulation of lipid droplets in both HepG2 cells and rat hepatocytes, and these were attenuated by GSO treatment. In HFD-fed mice, GSO improved HFD-induced dyslipidemia and hepatic insulin resistance. Increased hepatic lipid contents were observed in HFD-fed mice and it was lowered in GSO (500 mg/kg)-treated mice by 26.4% which was evident in histological analysis. Pathway analysis of hepatic global gene expression indicated that GSO increased the expression of genes associated with ${\beta}$-oxidation (Ppara, Ppargc1a, Sirt1, and Cpt1a) and decreased the expression of lipogenic genes (Srebf1 and Mlxipl), and these were confirmed with reverse transcription and quantitative polymerase-chain reaction. Conclusion: These findings suggest that GSO has a beneficial effect on NAFLD through the suppression of lipogenesis and stimulation of fatty acid degradation pathway.

• 한국CDE학회논문집
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• 제19권4호
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• pp.305-315
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• 2014

It is important to predict and measure the combat effectiveness (CE) of weapons system in battlefield for acquiring efficient weapon system. Moreover, quantitative calculation of weapon effectiveness under complicated and uncertain battlefield environment is also difficult based on the future network centric warfare. Many papers used the term of combat effectiveness and tried to study a lot of related issues about it. However, there is no paper dealing with the classification of study issue about CE and what will happen in this study field. In this paper, we proposed how to classify the study issue about CE and forecast future direction of this study field. Conceptually, CE is nothing but the assessment results to measure the ability of a military weapon system to accomplish its objective. We believe that it is an appropriate time to review the literature extensively on CE analysis because the research interests and the papers of CE are rapidly growing in these days. This paper reviewed many CE analysis papers, classified them according to their research content and the research methodology applied. Additionally, a comprehensive list of future research areas is also given.

• 대한치과기공학회지
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• 제42권3호
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• pp.220-227
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• 2020

Purpose: This study aims to investigate the cusp variation pattern of the Korean mandibular second premolar and to determine the difference in tooth diameter and surface area using a virtual three-dimensional model. Methods: Dental casts from 69 students were scanned as a virtual dental models with a three-dimensional dental model scanner. Tooth diameter, absolute and relative individual areas, total crown area, the number of lingual cusps and central groove pattern were analyzed using RapidForm 2004. The Mann-Whitney U-test and the Kruskal-Wallis test were performed to verify sexual dimorphism, the difference in tooth diameter and surface according to the cusp variation pattern (α=0.05). Results: There was no significant difference except in buccolingual diameter (p<0.05) and buccolingual diameter at the cervix (p<0.05). The relative surface area of the total clinical crown was 65.76% for the buccal half and 34.24% for the lingual half, with a ratio of 2:1. In the case of the presence of two lingual cusps, the ratio was 21.47% for the mesiolingual half and 14.12% for the distaolingual half, with a ratio of 3:2. The dominant central groove patterns of the second premolar were the H-pattern (42.0%), followed by the Y-pattern (37.7%), then the U-pattern (20.3%). The relative buccal half was largest in the U-pattern central groove and the relative lingual half was largest in the Y-pattern central groove (p<0.05). Conclusion: This study is significant in that it measured quantitative surface areas and the findings could be a meaningful reference to comprehend dental anatomy in Koreans.

• 항공우주기술
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• 제5권2호
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• pp.227-239
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• 2006

신뢰성 예측은 설계안 중 하나를 선택하거나, 적용되는 부품의 품질 수준, 부하경감(derating) 정도, 기존의 입증기술 또는 최신기술의 채택여부 등과 같은 사항을 설계시 결정하는 데에 합리적인 근거를 제공할 수 있으므로, 우주 시스템의 개발과정에 있어서 필수적인 사항으로 인식되고 있다. 신뢰성의 정량적인 표현을 위해서는 수치적인 정보와 그 정보를 생성하기 위한 기법의 정확성이 확보되어야 하며, 설계에 대한 평가를 돕고, 신뢰성 요구조건 할당, 시정조치 우선순위 결정 등의 기초자료로 적용하기 위하여 개념설계 초기 단계에서부터 수행되어야 한다. 대상품의 설계, 환경 요구조건, 운용환경 데이터, 고장률 데이터 또는 운용 프로파일의 변경이 발생할 때마다 업데이트되어야 한다. 본 논문에서는 우주시스템 개발과정에서 수행되는 신뢰성 예측을 위한 세부절차, 정량적 데이터의 도출 및 적용기법 등에 대하여 검토하였다.

• 디지털콘텐츠학회 논문지
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• 제11권4호
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• pp.463-471
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• 2010

하수 처리장은 화학적, 물리적, 생물학적 처리가 복합적으로 연계된 공정으로 구성 되는데, 각각의 단위공정과 전체시스템의 처리 성능 및 운영 상태의 정도를 파악 하려면 처리공정의 수학적 모델을 빠르게 연산 할 수 있는 컴퓨터 시뮬레이터를 이용하면 편리하다. 주어진 물리적 환경에서 처리공정의 오염물질, 화학물질, 생물학적 매체의 질량 수지를 계산하는 컴퓨터 시뮬레이터는 데이터의 입출력 과정과 수학모델의 연산과정을 효율적으로 수행하는 응용 소프트웨어로써 처리조 내부에서 일어나는 반응의 상태를 정량적으로 추산하는 도구이다. 이러한 시뮬레이션 소프트웨어는 처리시설의 성능 및 효율을 예측하여 운용자에게 최적 관리를 위한 의사결정의 타당성을 제공하게 되는데, 시뮬레이션 소프트웨어를 처리시설에 적합하도록 시나리오를 설정하고 데이터 수집 시스템에 연결하면 실시간으로 처리시설의 분석이 가능한 자동화 운영 시스템의 역할을 수행한다. 본 논문에서는 통합전산망에서 수집되는 데이터를 시뮬레이션 소프트웨어에서 운용, 실제 운영 상태와 시뮬레이션 결과를 실시간 비교, 분석하여 최적의 운전인자를 도출할 수 있는 시나리오 운영 소프트웨어 "WEC-Sim"의 설계 및 구현에 대하여 논한다.

• Earthquakes and Structures
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• 제14권6호
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• pp.577-587
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• 2018

The quantitative assessment of the seismic collapse risk of a structure requires the usage of an optimal intensity measure (IM) which can adequately characterise the severity of the ground motion. Research suggests that the average spectral acceleration ($Sa_{avg}$) may be an efficient and sufficient alternate IM as compared to the more traditional first mode spectral acceleration, $Sa(T_1)$, particularly during seismic collapse risk estimation. This study primarily presents a comparative evaluation of the sufficiency of the average spectral acceleration with respect to ground motion duration, and secondarily assesses the impact of ground motion duration on collapse risk estimation. By assembling a suite of 100 historical ground motions, incremental dynamic analysis of 60 different inelastic single-degree-of-freedom (SDF) oscillators with varying periods and ductility capacities were analysed, and collapse risk estimates obtained. Linear regression models are used to comparatively quantify the sufficiency of $Sa_{avg}$ and $Sa(T_1)$ using four significant duration metrics. Results suggests that an improved sufficiency may exist for $Sa_{avg}$ when the period of the SDF system increases, particularly beyond 0.5, as compare to $Sa(T_1)$. In reference to the ground motion duration measures, results indicated that the sufficiency of $Sa_{avg}$ is more sensitive to significant duration definitions that consider almost the full wave train of an accelerogram ($SD_{a5-95}$ and $SD_{v5-95}$). In order to obtain a reduced variability of the collapse risk estimate, the 5-95% significant duration metric defined using the Arias integral ($SD_{a5-95}$) should be used for seismic collapse risk estimation in conjunction with $Sa_{avg}$.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.286-291
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• 2008

Insulation of refrigerator with gasket material near door becomes the technical point at the aspect of heat loss and energy efficiency. Heat loss of refrigerator through the gasket is nearly 30%. In this paper, quantitative evaluation method of heat loss through gasket in established suggest the method for the improvement of heat loss. To analyze the heat transfer, we have used the common software Fluent that is used to CFD. Because of using the convection coefficient of heat transfer, we have solved only the equation of energy for heat transfer. As a result, we have known that heat loss flows through the heat flux vector and that the heat gathered out of the outside iron plate is transferred inner part through the gasket and ABS, etc. Through the result of the numerical simulation that use sub-gasket, we have known that we are able to reduce the heat loss about $20{\sim}40%$. when we applied that sub-gasket on a real refrigerator, the power consumption had reduced about 4.76%. In addition, when we applied a more improved sub-gasket on a real refrigerator and measured the power of the refrigerator the power consumption does reduce about 3% and we will try to apply the improved sub-gasket on a new models of refrigerator.

• Journal of the Optical Society of Korea
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• 제19권2호
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• pp.136-143
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• 2015

Image deblurring by a deconvolution method requires accurate knowledge of the blur kernel. Existing point spread function (PSF) models in the literature corresponding to lens aberrations and defocus are either parameterized and spatially invariant or spatially varying but discretely defined. In this paper, a parameterized model is developed and presented for a PSF which is spatially varying due to lens aberrations and defocus in an imaging system. The model is established from the Seidel third-order aberration coefficient and the Hu moment. A skew normal Gauss model is selected for parameterized PSF geometry structure. The accuracy of the model is demonstrated with simulations and measurements for a defocused infrared camera and a single spherical lens digital camera. Compared with optical software Code V, the visual results of two optical systems validate our analysis and proposed method in size, shape and direction. Quantitative evaluation results reveal the excellent accuracy of the blur kernel model.

• 대한인간공학회지
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• 제25권3호
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• pp.49-60
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• 2006

Technological encroachment provides human operators with flood of information that must be analyzed to understand the environment and make judgments that lead to strategic actions. Further, the environment is not static and therefore uncertain, changing its aspect dynamically. Complexity accompanied with its dynamics imposes substantial difficulty to human operators' task. Criticality of having situational understanding becomes more important than ever. Situationalunderstanding requires the human operators possessing tacit knowledge in order for them to make the sense out of the situation while interacting with information from many heterogeneous sources, the notion of sensemaking. Sensemaking refers to the process of developing mental framework to assemble pieces of information representing different aspects of the environment that can be used to develop one's own actionable knowledge to implement their judgments in the uncertain environment. Therefore, judgment process and performance is a key component of sensemaking process. Among many judgment and decision making models, the lens model with its extension can be utilized to partially describe the judgmental aspect of sensemaking. One of the lens model parameters, unmodeled knowledge, can be a corresponding quantitative measure for the tacit knowledge that plays an important role in sensemaking. In this paper, a comprehensive literature for sensemaking is provided to formally define the notion of sensemaking in the military domain. Also, it is proposed that there is a crucial link between the sensemaking and human judgment process and performance from the lens model perspective. Potential implications for experimental framework are also proposed.