• Earthquakes and Structures
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• 제10권1호
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• pp.105-123
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• 2016

In this paper, using the probabilistic methods, the seismic demand of buckling restrained braced frames subjected to earthquake was evaluated. In this regards, 4, 6, 8, 10, 12 and 14-storybuildings with different buckling restrained brace configuration (including diagonal, split X, chevron V and Inverted V bracings) were designed. Because of the inherent uncertainties in the earthquake records, incremental dynamical analysis was used to evaluate seismic performance of the structures. Using the results of incremental dynamical analysis, the "capacity of a structure in terms of first mode spectral acceleration", "fragility curve" and "mean annual frequency of exceeding a limit state" was determined. "Mean annual frequency of exceeding a limit state" has been estimated for immediate occupancy (IO) and collapse prevention (CP) limit states using both Probabilistic Seismic Demand Analysis (PSDA) and solution "based on displacement" in the Demand and Capacity Factor Design (DCFD) form. Based on analysis results, the inverted chevron (${\Lambda}$) buckling restrained braced frame has the largest capacity among the considered buckling restrained braces. Moreover, it has the best performance among the considered buckling restrained braces. Also, from fragility curves, it was observed that the fragility probability has increased with the height.

• 한국수소및신에너지학회논문집
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• 제30권2호
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• pp.155-162
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• 2019

The energy management technology for an independent fuel cell-battery hybrid system is developed for a household usage. To develop an efficient energy management technology, a simulation model is first developed. After the model is verified with experimental results, three energy management schemes are developed. Three control techniques are a fuzzy logic control (FLC), a state machine control (SMC), and a hybrid method of FLC and SMC. As the fuel cell-battery hybrid system is used for a house, battery state of charge (SOC) regulation is the most important factor for an energy management because SOC should be kept constant every day for continuous usage. Three management schemes are compared to see SOC, power split, and fuel cell power variations effects. Experimental results are also presented and the most favorable strategy is the state machine combined fuzzy control method.

• Child Health Nursing Research
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• 제25권2호
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• pp.85-94
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• 2019

Purpose: This study presents methodological research that aimed to verify the content validity, construct validity, reliability, and criterion-related validity of the Child Abuse Potential Inventory (CAPI), originally developed by Milner and then translated into Korean by Ahn. Methods: Data used in this study were collected from 209 mothers of infants, toddlers, and children of preschool age in D metropolitan city. The collected data were analyzed using SPSS version 24. Results: The Korean version of the Child Abuse Potential Inventory (K-CAPI) was developed by condensing 44 of the original 77 CAPI items. Four factors of K-CAPI were extracted using principal component analysis. These 4 factors-distress; problems with child, self, family, and others; unhappiness; rigidity-accounted for 54.01% of variance. The Cronbach's ${\alpha}$ was .96, the Guttman split-half coefficient was .88, and test-retest reliability was r=.86 (p<.001). Conclusion: The results of this study established the reliability and validity of the K-CAPI and found it to be an appropriate tool to evaluate mothers' potential to abuse their children.

• Human Ecology Research
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• 제51권5호
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• pp.537-549
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• 2013

The purpose of this study was to develop an objective Ego Strength Scale for Children useful in research and clinical fields for measuring the ego strength of 3rd-6th grade children and to test its validity and reliability. For these purposes, we conducted a two-stage study. First, the scale was developed through data collection, composition of components and questions, a preliminary survey, and a main survey. The main survey was conducted with 1,185 3rd-6th grade children in Seoul and Gyeonggi province, and analyzed through exploratory factor analysis and reliability analysis. Second, the scale we developed was validated through confirmatory factor analysis and convergent-discriminant validity analysis for testing validity related to internal structure. The secondary survey was conducted with 5,494 3rd-6th grade children in Seoul and the province of Gyeonggi, Chungcheong, Gangwon, Jeolla, Gyeongsang, and Jeju. The study concluded the following: First, the scale was designed to measure 4 factors: competence, initiative, elasticity, and sociability using 26 questions. Second, the Ego Strength Scale for Children was found to be highly valid through validity tests. In addition, it showed high reliability in an internal consistency test and split-half reliability test. As this study developed and validated the Ego Strength Scale for Children in the current situation in which there are few objective instruments to measure children's ego strength, it is meaningful in that it laid the basis for broader future research on ego strength.

• 대한기계학회논문집
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• 제14권1호
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• pp.112-118
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• 1990

본 연구에서는 ASTM-E24.01.06에서 제안하고 있는 실험방법을 응용하여 균열 정지 파괴인성값을 측정하였다.즉 쐐기와 분리형 부싱(wedge and split bushing)으 로 압축하중을 가함으로 균열선 웨지하중 시편[crack line wedge loaded specimen(CL- WL시편)]에 인장력을 발생시켜서 균열정지 응력확대계수( $K_{1a}$)를 결정하였다. 그리고 균열개시 응력확대계수가 균열정지 응력확대계수에 미치는 영향들을 여러가지 재료들에 대하여 체계적으로 검토하였다.다.

• Journal of the Korean Wood Science and Technology
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• 제43권6호
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• pp.861-867
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• 2015

유리섬유 보강적층재의 파괴인성을 평가하기 위하여 Compact tension (CT)형 시험을 실시하였다. 보강재는 직물형 유리섬유와 시트형 유리섬유강화플라스틱을 사용하였으며, 보강적층재는 층재사이에 보강재를 삽입 적층하였다. ASTM D5045에 의거하여 CT형 시험편을 제작하였다. 시험편의 길이는 끝면거리를 고려하여 선정하였으며, 인위적인 노치 끝에 볼트구멍(12 mm, 16 mm, 20 mm)을 선공하였다. 시트형 유리섬유강화플라스틱 보강적층재의 파괴인성하중은 보강하지 않은 적층재보다 최대 33% 증가하였으며, 직물형 유리섬유 보강적층재는 최대 152% 증가하였다. 이중외팔보(Double Cantilever Beam)이론에 의한 응력확대계수는 시트형 유리섬유강화플라스틱 보강적층재의 경우 1.08~1.38이었으며, 직물형 유리섬유 보강적층재는 1.38~1.86이었다. 이는 직물형 유리섬유 보강적층재의 경우 유리섬유와 층재의 섬유배열방향이 직교하여 파괴하중으로 인한 목재의 할렬진행을 억제시켰기 때문이다.

• Asian Journal of Atmospheric Environment
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• 제11권1호
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• pp.1-14
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• 2017

For the quantitative analysis of volatile organic compounds (VOC), the use of a proper solvent is crucial to reduce the chance of biased results or effect of interference either in direct analysis by a gas chromatograph (GC) or with thermal desorption analysis due to matrix effects, e.g., the existence of a broad solvent peak tailing that overlaps early eluters. In this work, the relative performance of different solvents has been evaluated using standards containing 19 VOCs in three different solvents (methanol, pentane, and hexane). Comparison of the response factor of the detected VOCs confirms their means for methanol and hexane higher than that of pentane by 84% and 27%, respectively. In light of the solvent vapor pressure at the initial GC column temperature ($35^{\circ}C$), the enhanced sensitivity in methanol suggests the potential role of solvent vapor expansion in the hot injector (split ON) which leads to solvent trapping on the column. In contrast, if the recurrent relationships between homologues were evaluated using an effective carbon number (ECN) additivity approach, the comparability assessed in terms of percent difference improved on the order of methanol (26.5%), hexane (6.73%), and pentane (5.24%). As such, the relative performance of GC can be affected considerably in the direct injection-based analysis of VOC due to the selection of solvent.

• 대한교통학회지
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• 제24권4호
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• pp.81-91
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• 2006

최근 지속가능 한 개발에 대한 관심이 높아지면서 교통분야에서도 지속가능 한 개발을 위한 대중교통활성화에 많은 노력을 기울이고 있으며, 대중교통육성법 제정, 대중교통분야의 투자확대, 대중교통체계개편 등의 다양한 정책들이 시행되고 있다. 이와 같이 대중교통에 대한 중요성이 어느 때보다도 높은 시기에, 현재의 대중교통경쟁력 수준을 평가하는 것은 매우 중요한 과정이라 할 수 있다. 이를 통해 현재까지의 대중교통정책 및 그 효과에 대한 이해의 폭을 넓힐 수 있고 향후 효과적인 대중교통정책을 수립하는데 도움을 줄 수 있기 때문이다. 그러나 기존의 연구는 대중교통의 전반적인 경쟁력 수준을 평가하기에는 미흡한 점이 많았으며 국제비교연구 또한 전무한 실정이다. 본 연구에서는 대중교통의 여러 평가요소를 고려한 12개의 평가지표 선정하고, 요인분석을 통하여 4개의 요인을 선정하였으며, 선정된 요인을 이용하여 군집분석을 실시하여 60개의 세계주요도시를 8개의 군집으로 분류하고 대중교통경쟁력수준을 평가하였다. 또한 지역(대륙)별 도시들 및 서울시의 대중교통특성을 파악하였으며, 각 도시의 대중교통경쟁력수준과 대중교통수단분담률의 관계를 다중회귀분석을 이용하여 분석하였다.

• 한국간호교육학회지
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• 제22권2호
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• pp.228-239
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• 2016

Purpose: To develop and test the validity and reliability of the Korean version of the Moral Distress Scale-Revised (KMDS-R) to assess its applicability to Korean hospital nurses. Methods: The KMDS-R was articulated through forward-backward translation methods. Internal consistency reliability, construct and criterion validity was calculated using SPSSWIN(19.0). Survey data were collected from 188 nurses from a university hospital in Gangwon-do, South Korea. Results: The KMDS-R showed reliable internal consistency with a Cronbach's alpha of .69-.87 and a Guttman Split-half of .69-.82 for the total scale. Factor loading of the 21 items on the five subscales ranged from .41-.80. The KMDS-R was validated by factor analysis and explained 63% of moral distress for Korean hospital nurses. Criterion validity compared to Yoo's MDS showed significant correlation. Conclusion: The results suggest promising evidence of the KMDS-R's reliability and validity. It is used to measure moral distress for Korean hospital nurses.

• Current Optics and Photonics
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• 제5권3호
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• pp.250-260
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• 2021

A tapered As₂S₃ photonic crystal fiber (PCF) with four layers of air holes in a hexagonal array around the core is designed in this paper. Numerical simulation shows that the dispersion D decreases and the nonlinearity coefficient γ increases from the thick to the thin end along the tapered PCF. We simulate the midinfrared pulse compression in the tapered As₂S₃ PCF using the adaptive split-step Fourier method. Initial Gaussian pulses of 4.4 ps and a central wavelength of 2.5 ㎛ propagating in the tapered PCF are located in the anomalous dispersion region. With an average power of assumed input pulses at 3 mW and a repetition frequency of 81.0 MHz, we theoretically obtain a pulse duration of 56 fs and a compression factor of 78 when the pulse propagates from the thick end to the thin end of the tapered PCF. When confinement loss in the tapered PCF is included in the simulation, the minimum pulse duration reaches 72 fs; correspondingly, the maximum compression factor reaches 61. The results show that in the anomalous-dispersion region, midinfrared pulses can be efficiently compressed in a dispersion-decreasing and nonlinearity-increasing tapered As₂S₃ PCF. Due to confinement loss in the tapered fiber, the efficiency of pulse compression is suppressed.