• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.711-714
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• 2008

The objective of this study is to analyze the relationship between the watershed characteristics and the critical duration of design rainfall. For estimation of critical duration, adjustment Huff's method and ILLUDAS urban runoff model were applied to urban 21 areas. Watershed characteristics such as area, channel length, channel slope, shape factor, and pipe density were used to simulate correlation analysis. The conclusions of this study are as follows; it is revealed that critical duration is influenced by the watershed characteristics such as pipe density, area and channel length. Also, multiple regression analysis using watershed characteristics is carried out and the determination coefficient of multiple regression equation shows 0.972.

• 보건의료산업학회지
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• 제7권4호
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• pp.105-117
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• 2013

The purpose of this study was to identify the relationships among critical thinking disposition, professional self-concept and clinical competence in nursing students. The participants were 291 nursing students in Gwangju Province. A questionnaire survey was conducted from March 02 to 16, 2013. Data were analyzed using descriptive statistics, t-test, ANOVA, Scheffe test, pearson's correlation coefficients, and stepwise multiple regression analysis with SPSS/WIN 20.0 version. There was a significant positive correlations among critical thinking disposition, professional self-concept, and clinical competence. The variable predicting clinical competency were professional self-concept and critical thinking disposition. These factors accounted for 44.1% of the variance. The findings of this study suggest that the most influential factor for clinical competence was professional self-concept. Therefore it is necessary to improve professional self-concept through effective education program.

• Tuberculosis and Respiratory Diseases
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• 제54권5호
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• pp.495-509
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• 2003

연구배경 : 호중구에 의해 매개되는 염증반응은 호중구의 수명이 매우 짧기 때문에 대부분 자연 종결된다. 패혈증에서는 이러한 호중구의 아포프토시스가 감소되어 수명이 연장되어 있어서 지속적인 염증반응이 일어나게 된다. 호중구의 수명 연장을 유도하는 많은 염증 매개 물질들이 nuclear factor-${\kappa}B$ 전사인자에 의해 조절되기 때문에 이 연구에서는 nuclear factor-${\kappa}B$가 패혈증 환자에서 관찰되는 호중 구의 아포프토시스 억제와 연관이 있을 것으로 가정하였다. 방법 : 건강한 정상인과 패혈증 환자의 호중구를 정맥혈로부터 신선하게 분리하여 실험하였다. 호중구의 아포프토시스는 특징적인 아포프토시스의 형태를 보이는 세포를 광학현미경으로 세거나 Annexin V를 이용한 유세포분석법으로 정량하였다. Nuclear factor-${\kappa}B$의 활성도는 면역형광 엽색법 또는 electrophoretic mobility shift assay로 판단하였다. 항아포프토시스 단백인 X-linked inhibitor of apoptosis의 발현 정도는 western blot으로 평가하였다. 결과 : 패혈증 환자에서 자발적 아포프토시스가 감소되어 있음을 확인하였다. 패혈증 환자의 호중구에 cycloheximide를 처치하였을 때 아포프토시스가 유의하게 증가하여 아포프토시스 감소가 새로운 단백 합성에 의존적임을 관찰하였다. 패혈증 환자의 호중구에서는 정상인과는 달리 기저상태에서도 nuclear factor-${\kappa}B$가 핵 내로 이동되어 활성화되어 있었고 nuclear factor-${\kappa}B$의 활성을 억제하였을 때 아포프토시스의 억제가 반전되었다. 또한 nuclear factor-${\kappa}B$에 의존적인 X-linked inhibitor of apoptosis 단백의 발현 수준이 정상인의 호중구에서는 24시간 동안 배양하면서 점차 감소하였지만 패혈증 환자의 호중구에서는 지속적으로 발현 수준이 유지되었다. 결론 : 패혈증 환자에서 관찰되는 호중구의 아포프토시스 억제에는 nuclear factor-${\kappa}B$ 전사인자의 활성화에 의한 생존 단백의 유도가 관여할 것으로 생각하였다.

• Progress in Superconductivity
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• 제3권1호
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• pp.130-133
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• 2001

A multifilamentary Bi-2223 HTS tape for superconducting power applications was studied through the fabrication of 250-meter long tapes by the PIT(powder in tube) process. To fabricate continuous long wire, a drawing machine, a two-drum bull block and a rolled tape winding machine were developed. Especially, 250-meter long tapes were heat treated in the shape of pancake coil to reduce the heat affect zone and to achieve the high critical current. Engineering critical current density was improved through both the enhancements of critical current density by control of thermal process and the increase of filling factor by using thin Ag alloy sheath tubes less than 1.5 mm in thickness. We have made successfully 250-meter long 37 filamentary tapes with high filling factor up to 31 % employing the modified drawing and rolling technique. The critical current of 250-meter long tapes with pancake coil type was measured by transport method at self-field up to 250 gauss of center field. The measured values, based on the transport critical current at self-field, $I_{c}$ -B characteristics and magnetic field analysis, are 34 A of I$_{c}$ and 4.0 $kA/\textrm{cm}^2$ of $J_{e}$ at 250 m, 77 K, and 0 T. We also have achieved the 56 A of I$_{c}$ and 7.0 $0 kA/\textrm{cm}^2$ of$ J_{e}$ in short tapes at 77K, self-field, and 1$mutextrm{V}$/cm.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2003년도 학술.기술논문발표회
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• pp.139-142
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• 2003

Traditionally, the thickness of fire protection materials of structural elements such as beam and column have been decided by fire test using the predominant steel section of $H-300{\times}300{\times}10{\times}15$ for column and $H-400{\times}200{\times}8{\times}13$ for beam in Korea. But this way of determination of fire protection thickness yields very unduly results. Because the temperature-increment rate of structural steel elements depends mainly on magnitude of their cross-areas. In general, the thicker size of cross-areas for structural elements, the lower temperature shows up. It had already proved that the fire protection thickness only depends on the size of cross-areas and the fire protection method for three-fide or four-side exposed conditions in European countries, the United State of America and so on. To demonstrate there would be differences among various cross-areas for structural elements, we conducted several fire tests with full-scale specimens of beams and columns. For the determination of critical temperature for steel section when the fire resistant performance is needed to be decided, we conducted with a loaded fire test for beam and column, respectively. The small column in 1.0 meter length and beam in 1.5 meter length were used in order to deprive the rational fire protection thickness of structural elements such as beam and column, respectively. After test, we could obtain there were significant temperature lass between higher cross-areas and lower cross-areas. The critical temperature of steel as a criterion is used 538$^{\circ}C$ for column and 593$^{\circ}C$ for beam which is from ASTM E 119 because we don't make provisions as critical temperature by elements. We could consider that the best way of determination of fire protection thickness is using the following multi-regression equation which was deprived from several fire tests using the concept of section factor, FR(column) = 0.17 +5191.49t A/Hp + 40.77t, FR(beam) = 0.25 +6899.31t A/Hp + 32.60t(where, FR means fire resistant time, t means thickness, A means cross-area and Hp means heated parameter).

• 한국자동차공학회논문집
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• 제13권4호
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• pp.174-181
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• 2005

In order to investigate the behavior of fatigue crack growth of SiC-particulate- reinforced Al-Si alloy composites, fatigue tests using single edge notched tension(SENT) specimens were performed. Composite materials were manufactured by using both permanent die casting and extrusion processes with different volume fractions of $10\%\;and\;20\%$. $SiC_p-reinfurced$ Al-Si composites showed the increased levels of threshold stress intensity factor range, ${\Delta}K_{th}$, for the increased volume fractions of SiC particles, which implies the increased fatigue crack growth resistance at the threshold or low ${\Delta}K$ levels, compared to the unreinforced Al-Si alloy. In the Paris region, however, the composites showed the increased rate of crack growth resulting in the unfavorable effects on the fatigue crack growth resistance. Critical stress intensity factor range at unstable crack growth leading to final fracture decreased as the volume fraction of SiC particle increased, because of the reduced fracture toughness of the composites. Extruded materials showed higher threshold and critical values than the cast materials.

• 수산경영론집
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• 제35권1호
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• pp.117-132
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• 2004

This study attempts to suggest a new approach of the estimation of range and degree of fisheries damages caused by a large scale of reclamation undertaken in coastal area using the central limit theorem(CLT) in statistics. The key result of the study is the introduction of the new concept of critical variation of environmental factor($d_{c}$). The study defines $d_{c}$ as a standard deviation of the sample mean($\bar{X}$) of environmental factor(X), in other words, $\frac{\sigma}{ \sqrt{n}}$. The inner bound of $d_{c}$ could be the area of fisheries damages caused by public coastal undertaking. The study also defines the decreasing rate of fisheries production$\delta_{\varepsilon}$, in other words, degree of fisheries damages, as the rate of change in the distribution of sample mean(($\bar{X}$), caused by the continuous and constant variation of environmental factor. Therefore $\delta_{\varepsilon}$ can be easily calculated by the use of table of the standardized normal distribution.

• 품질경영학회지
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• 제38권1호
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• pp.64-74
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• 2010

Since management of information resources is getting more complicated in the distributed, heterogeneous computing environment, the capability of monitoring and controlling the dispersed information resources is perceived as a critical success factor for the effective enterprise-wide information resource management. Integrated Control Architecture(ICA) provides that capability. Utilizing such architecture, we can manage corporate information resources more efficiently, perform impact analysis for changes in information resources, and alleviate the human effort by automating the monitoring of critical information resources. In this paper, we propose a conceptual framework and metamodel of ICA.

• 디지털융복합연구
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• 제13권1호
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• pp.85-92
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• 2015

최근 기업의 평균수명이 점점 단축되고 있으며 기업환경 또한 급격하게 변화하고 있다. 따라서 본 연구에서는 일본 시니세의 장수요인 분석을 통하여 기업의 장수, 즉 계속기업의 해답을 얻고자 하였다. 시니세의 조사 결과와 함께 도라야, 데이코쿠 두 시니세의 장수요인을 분석해 본 결과 그 요인은 신용과 전통, 고객맞춤상품개발, 경영방식의 변화, 글로벌 시장 개척 등의 요인이 장수의 핵심요인으로 설명되었다. 또한 본 연구에서는 이러한 주요요인을 중심으로 계층적 의사결정기법(AHP)을 이용하여 각각의 사례와 선행연구에서 조사된 요인의 중요성을 분석하여 장수요인에 대한 주요 변수를 예측 및 분석하였다. 그러나 변수선정과 사례의 성공요인이 갖고 있는 한계점 등을 고려해 볼 때 공통적 성공 요인으로 분류하기 위해서는 많은 사례가 필요할 것으로 볼 수 있다. 본 연구는 향후 장수요인을 분석하는데 매우 유용한 지침이 될 수 있을 것으로 기대된다.

• Progress in Superconductivity
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• 제4권2호
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• pp.184-188
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• 2003

Voltage-current characteristics of High Temperature Superconductor(HTS) tapes after applying the current beyond their critical current was investigated. When over-current is applied, the current begins to flow through the metal sheath instead of superconductor. The HTS tapes quenched were analyzed using V-I curve with various magnitudes of current. Two kinds of tapes were compared with each other to examine the influence of critical current on quench development. As a result, it was found that the resistance of superconductors and joule heat due to the over-current affect current distribution in HTS tapes. Critical current of HTS tapes was considered as a main factor deciding over-current characteristics.