• Journal of Electrochemical Science and Technology
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• 제15권2호
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• pp.276-290
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• 2024

A study of the transition from transitory state to steady state in DSSCs based on natural dyes is presented; cochineal was used as dye and Li⁺, Na⁺, and K⁺ were the ions added to the electrolyte. The photocurrent profiles were obtained as a function of time. Several DSSCs were prepared with different cations and their role and the transitory-to-steady transition was determined. A novel hybrid charge carrier source model based on the Heaviside function H(t) and the Lambert-Beer law, was developed and applied to analysis of the transient response of the output photocurrent. Additionally, the maximum effective light absorption coefficient α and the electronic extraction rate κ for each ion were determined: ${\alpha}_{Li^+,Na^+,K^+}\,=\,(0.486,\,0.00085,\,0.1126)\,cm^{-1}$, and also the electronic extraction rate ${\kappa}^{Li^+,Na^+,K^+}_{ext.}\,=\,(1410,\,19.07,\,19.69)\,cm\,s^{-1}$. The impedance model using Fick's second law was developed for carrier recombination to characterize the photocurrent.

• 기본간호학회지
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• 제24권3호
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• pp.189-199
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• 2017

Purpose: This study was conducted to examine the level of agreement between a standardized patient (SP) and a faculty member in the evaluation of nursing students' assessment and communication skills. Methods: Participants were 51 third year nursing students in a simulation practice of 'nursing care for a patient admitted with chest pain'. Using a 30-item checklist and a 16-item communication tool, a SP and faculty member evaluated the students' assessment and communication skills during the simulation. Results: The average values for percent agreement and kappa statistic for nursing assessment between the two evaluators were 85.3% and .48 respectively. Twenty of thirty items evaluating assessment skill had above moderate agreement (${\geq}.41$) by kappa between the evaluators. Seven of sixteen items evaluating communication and interpersonal skills showed above fair agreement (${\geq}.40$) between the two evaluators, which was measured by intraclass correlation coefficient. Conclusion: The findings show that the evaluation of the SP was consistent with those of the faculty member to a moderate degree. Clear guidelines for evaluating criteria and optimal time and effort for SP training are necessary to increase the reliability of standardized patients as evaluators in simulation-based nursing education.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.661-661
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• 2013

열전재료는 열-전기가 상호 가역적으로 변하는 재료로서, 에너지 변환소재 분야에서 널리 각광받고 있다. 열전재료의 성능은 무차원 열전성능지수(dimensionless figure of merit, $ZT={\alpha}^2{\sigma}T/{\kappa}$)로 평가된다. 여기서 ${\alpha}$는 제벡계수(Seebeck coefficient), ${\sigma}$는 전기전도도(electrical conductivity), ${\kappa}$는 열전도도(thermal conductivity), T는 Kelvin 온도를 나타낸다. 500 K에서 800 K까지의 중온 영역에서 우수한 열전특성을 보이는 $Mg_2X$ (X=Si, Ge, Sn)와 이들의 고용체는 성분원소가 독성이 없고, 매장량이 많아 친환경 열전재료로 각광받고 있다. $Mg_2X$ 고용체 중 $Mg_2Si-Mg_2Sn$ 고용체는 Si와 Sn의 큰 원자량 차이로 인해 낮은 열전도도와 높은 성능지수(ZT)를 얻을 것이라 예상되며 열전발전 소자로서의 응용이 기대된다. Sb가 도핑된 $Mg_{2+x}Si_{0.7}Sn_{0.3}Sb_y$ (x=0, 0.1, 0.2, y=0, 0.01) 고용체를 고상합성과 기계적 합금화로 합성한 후, 진공 열간압축 성형을 통해 성공적으로 제조하였다. X선 회절분석으로 상합성과 고용체 형성 여부를 확인하였고, Mg의 과잉첨가와 Sb 도핑에 따른 열전특성의 변화를 조사하였다.

• The Journal of Korean Physical Therapy
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• 제16권3호
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• pp.142-151
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• 2004

The purpose of this study was to determine the validity and the reliability of the WISCI II to ascertain its value in the walking function evaluation of spinal cord injury patient. The WISCI II consists of 20 variables with a total valus ranging from 6 to 20 score. A group of 23 spinal cord injury patient were included in this study. To determine the validity, kappa statistics between the WISCI II and SCIM II were measured. The result of this study are as follows: 1) In the validity study, the kappa statistics between the WISCI II and SCIM II were 0.79 and 0.84 for an initial total score and a discharge total score respectively, indicating a reasonable agreement between the two test. 2) In the reliability study, the Cronbach's alpha coefficient was 0.83 and 0.95 for total score indicating a good internal consistency. The finding suggest that the WISCI II demonstrated an acceptable validity and reliabilit for the evaluation of walking function capacity of spinal cord injury patient in clinical practice.

• 디지털융복합연구
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• 제14권2호
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• pp.519-527
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• 2016

이 연구는 BMI 분류기준과 9점-신체상평정척도 분류기준의 일치도를 조사하여 현장적용의 유용성을 확인하고, 여대생들이 체형에 대해 실제로 인식하고 정도를 파악하여 체형인식의 왜곡에 대한 올바른 정보와 비만의 기준에 대한 정보 제공에 목적이 있다. BMI 분류기준과 신체상평정척도 분류기준의 일치도, 그리고 여대생의 BMI에 따른 신체상 인식 정도를 알아보기 위하여 교차분석, Spearman의 등위차상관계수 및 카파통계량을 산출하였다. 분석결과 일반 여자대학생이 판정한 신체상 평정척도 분류기준과 BMI 분류기준은 통계적으로 ${\rho}=.719$(p<.001)로 높은 상관과 ${\kappa}=.506$(p<.001)로 보통 수준의 일치도를 나타냈다. 이러한 결과를 바탕으로 차후 신체상과 관련하여 인종의 특성에 따른 크기와 형태를 조정할 필요가 있으며 인구통계학적 특성이 다르거나 비만도가 높은 대상자를 선별하여 그들의 체형인식과 심리적인 측면에 관한 추가적인 연구가 필요하다.

• 동의생리병리학회지
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• 제34권3호
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• pp.142-148
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• 2020

The purpose of this study was to evaluate the validity of Deficiency and Excess Pattern Identification Questionnaire. The number of subjects enrolled in this study was 431. Pearson Correlation Coefficient analysis were conducted to reveal the correlation among Deficiency and Excess Pattern Identification Questionnaire, Grip Strength and Quality of life. ROC-curve analysis were used to suggest optimal cut off value. Cohen Kappa also used to analyze for diagnostic validity. The significant p-value was < .05. The Deficiency questionnaire had positive correlation with the score of the expert and negative correlation with Grip Strength and Quality of life (p<.001). The Excess questionnaire had positive correlation with the score of the expert and negative correlation with Quality of life (p<.001). The optimal cut off value was 56.5 to separate deficiency and non deficiency and 47.5 to separate excess and non-excess. Furthermore, AUC was .900 and .851 accordingly. Cohen Kappa value between deficiency questionnaire and the expert was .640. Cohen Kappa value between excess questionnaire and the expert was .513. This study reveals that Deficiency and Excess Pattern Identification Questionnaire is valid. However, further study considering of gender, age, and health condition and so on, is needed.

• Safety and Health at Work
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• 제12권4호
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• pp.445-451
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• 2021

Background: This study aimed to evaluate the reliability and validity of the self-administered questionnaire for Korean radiation workers. Methods: From May 24, 2016, to June 30, 2017, 20,608 participants completed the questionnaire, providing information on sociodemographics, lifestyle, work history and practices, medical radiation exposure, and medical history, which was linked to the National Dose Registry and the National Cancer Registry. The validity of the questionnaire was evaluated using the responses of 20,608 workers, and reliability was evaluated using the responses of 3043 workers who responded to the survey twice. Results: Responses concerning demographic characteristics and lifestyle showed reliability with a moderate-to-high agreement (kappa: 0.43-0.99), whereas responses concerning occupation and medical radiation exposure had a wide range of agreement (kappa: 0.05-0.95), possibly owing to temporal variability during employment. Regarding validity, responses to the question about the first year of employment had an excellent agreement with the national registry (intraclass correlation coefficient = 0.9); however, responses on cancer history had a wide range of agreement (kappa: 0.22-0.85). Conclusion: Although the reliability and validity of the questionnaire were not distinguished by demographic characteristics, they tended to be low among participants whose occupational radiation exposure was minimal. Overall, the information collected can be reliable for epidemiological studies; however, caution must be exercised when using information such as medical exposure and work practices, which are prone to temporal variability.

• 대한원격탐사학회지
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• 제39권5_2호
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• pp.837-847
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• 2023

본 연구는 사고현장에서 화학물질로 인해 발생한 사고지점의 피해면적을 식생지수로 산출하는 방안을 연구하였다. 자료수집은 두 종류의 드론을 활용하였으며, 사진측량기법을 적용한 3차원 점군자료에서 피해면적을 산출하였다. 다중분광센서의 분광대역 정보를 활용하여 제작한 정사영상을 토대로 식생지수 영상을 제작하였고, 임계값에 따른 피해면적의 결과로 사고현장에 대한 통계를 분석하였다. 근적외선 밴드 기반의 식생지수 Kappa 값은 0.79, 녹색 밴드 기반의 식생지수는 0.76으로 화학물질사고 조사현장에서 식생지수를 활용한 피해면적 분석 방법을 활용할 수 있을 것으로 판단된다.

• 대한원격탐사학회지
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• 제27권4호
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• pp.457-466
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• 2011

본 연구의 목적은 Level 3 type 북한 토지피복도를 작성하고 생물계절 특성을 파악 하는 데 있다. 2008년과 2009년에 촬영된 88장과 8장의 MODIS NDVI를 MVC 하여 질이 향상된 영상에 ISODATA 알고리즘을 적용하였다. 생물계절 상 분석을 기반으로 북한의 토지피복도를 구축하고 중분류에 대해서는 정확도 검정을 하였다. 결과, 총 27개 클래스의 북한 토지피복도가 생산되었다. 토지피복은 17개의 산림 서식지, 토지이용은 7개의 농경지와 2개의 시가지, 그리고 한 개의 수역을 포함한다. Level 3 type 생물계절 특성은 휴지기(${\sigma}^2$ = 0.348)와 식생이 급격히 생장하는 봄철(${\sigma}^2$ = 0.347)의 역동성이 가장 컸다. Level 2 type에 대한 정확도 검정에서, 전체 정확도는 85.85%(851/955), Kappa 계수는 0.84 였다. 현장 접근이 불가능한 북한의 토지피복도 구축에 생물계절 상 분석기법 적용은 오분류를 최소화하고 분류정확도를 향상시키는데 기여하였다.

• 한국세라믹학회지
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• 제53권1호
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• pp.43-49
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• 2016

This analyzed a Young's modulus (E), a thermal expansion coefficient (TEC, ${\beta}$) and a thermal conductivity (${\kappa}$) of the material with simple cubic particulate inclusion using two model structures: a parallel structure and a series structure of laminated layers. The derived ${\beta}$ equations were applied to calculate the ${\beta}$ value of the W-MgO system. The accuracy was higher for the series model structure than for the parallel model structure. Young's moduli ($E_c$) of sintered porous alumina compacts were theoretically related to the development of neck growth of grain boundary between sintered two particles and expressed as a function of porosity. The series structure model with cubic pores explained well the increased tendency of $E_c$ with neck growth rather than the parallel structure model. The thermal conductivity of the three phase system of alumina-mullite-pore was calculated by a theoretical equation developed in this research group, and compared with the experimental results. The pores in the sintered composite were treated as one phase. The measured thermal conductivity of the composite with 0.5-25% porosity (open and closed pores) was in accordance with the theoretical prediction based on the parallel structure model.