• 한국표면공학회지
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• 제46권1호
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• pp.29-35
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• 2013

The effect of DC bias on the growth of nanocrystalline diamond films on silicon substrate by microwave plasma chemical vapor deposition has been studied varying the substrate temperature (400, 500, 600, and $700^{\circ}C$), deposition time (0.5, 1, and 2h), and bias voltage (-50, -100, -150, and -200 V) at the microwave power of 1.2 kW, working pressure of 110 torr, and gas ratio of Ar/1%$CH_4$. In the case of low negative bias voltages (-50 and -100 V), the diamond particles were observed to grow to thin film slower than the case without bias. Applying the moderate DC bias is believed to induce the bombardment of energetic carbon and argon ions on the substrate to result in etching the surfaces of growing diamond particles or film. In the case of higher negative voltages (-150 and -200 V), the growth rate of diamond film increased with the increasing DC bias. Applying the higher DC bias increased the number of nucleation sites, and, subsequently, enhanced the film growth rate. Under the -150 V bias, the height (h) of diamond films exhibited an $h=k{\sqrt{t}}$ relationship with deposition time (t), where the growth rate constant (k) showed an Arrhenius relationship with the activation energy of 7.19 kcal/mol. The rate determining step is believed to be the surface diffusion of activated carbon species, but the more subtle theoretical treatment is required for the more precise interpretation.

• 한국대기환경학회지
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• 제26권4호
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• pp.449-452
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• 2010

In this article, the performance of the THC analyzer was inspected using two different span gases of methane ($CH_4$) and propane ($C_3H_8$). To explore the effect of standard gas selection, MicroFID system was tested by the following procedures. Initially, the system is spanned by propane gas of 60 ppm (or 180 ppmC). The system is then run against methane standards prepared at 5 different concentrations of 200, 250, 300, 400, and 500 ppm. According to the suggestion of the KMOE's test procedure to use multiplying a factor of 3 (for propane), the resulting THC values derived by methane standards were systematically biased with ~500% error relative to true value. This paper discusses the interpretation procedures to obtain the least biased THC values for a given span set-up.

• 천문학회보
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• 제46권2호
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• pp.43.3-43.3
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• 2021

The peculiar motion of the observer, if not (or only imperfectly) accounted for, is bound to induce a well-defined clustering signal in the distribution of galaxies. This spurious signal is related to the Kaiser rocket effect. We examined the amplitude of this effect and discuss possible implications for analysis and interpretation of future cosmological surveys. We found that it can in principle bias very significantly the inference of cosmological parameters, especially for primordial non-Gaussianity.

• 한국언론정보학보
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• 제71권
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• pp.274-298
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• 2015

이 연구는 프레임 개념과 편향성 개념을 통합적으로 연결해 재난 사고 뉴스의 정치사회적 의미를 해석했다. 국내 언론이 세월호 침몰 사고라는 특수한 재난 사고의 문제 정의, 원인 해석, 도덕적 평가, 그리고 사후 처방을 제시하는 과정에 어떤 프레임을 더 편향되게 배치했는지를 이론적으로 검정해 보았다. 또한 프레임의 편향성이 정치적 이념을 달리하는 보수 신문과 진보 신문 간에 어떤 차이가 있는지 비교 분석해 보았다. 내용 분석 결과를 제시하면 다음과 같다. 첫째, 세월호 사고 진단 프레임에서는 전체적으로 파편화>개인화>권위무질서>극화의 순으로 편향되어 있었다. <조선일보>는 파편화 편향성이, 한겨레는 권위무질서 편향성이 상대적으로 컸다. 둘째, 사고 평가에서는 책임 프레임>도덕적 프레임>문제 해결 프레임>사고 원인 프레임의 순으로 편향되어 나타났다. <조선일보>는 책임 프레임, 도덕적 프레임 편향적으로 사고를 평가했다. <한겨레>는 책임 프레임, 문제 해결 프레임 편향성이 두드러졌다. 셋째, 책임 소재 프레임에서는 정부>개인>조직의 순으로 편향되어 제시됐다. <조선일보>는 정부와 개인의 책임 편향성을 드러낸 반면에, <한겨레>는 상대적으로 정부에 책임을 더 강조하면서 조직에 대한 책임 편향성도 보였다. 넷째, 문제 해결 프레임에서는 전체적으로 주제적 프레임과 일화적 프레임 편향성이 엇비슷한 수준으로 나타났다. <조선일보>는 일화적 프레임으로, <한겨레>는 주제적 프레임으로 더 편향화하는 차이를 보였다. 세월호 사고의 평가와 해석에 대한 언론의 프레임 편향성과 함께 이념적 차이에 따른 언론 간의 편향성 차이를 사회적 맥락 차원에서 토론했다.

• 한국임상수의학회지
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• 제28권1호
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• pp.108-112
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• 2011

In clinical settings, researchers often want to assess agreement between two measurements (or tests) of the same continuous variable. For example, when new point-of-care analyzer for testing blood glucose level were introduced clinicians need to compare results from standard or established laboratory method of measurement to those of new or point-of-care analyzer. The question in a method-comparison study would either of two different methods be used to measure the same variable equivalently. In this paper common misuse of statistical methodologies seen in the medical literatures such as correlation coefficient and paired t-test are discussed. The Bland-Altman technique has been widely used for this purpose and provides a graphic in presentation of the findings from a method-comparison study, with a mean value of measurement, this bias and the limits of agreement. For ease of application and interpretation of this technique we discussed the analysis procedure and illustrated with two worked examples. Finally, a number of alternative ways in which data can be analysed and reported in such studies were reviewed.

• 한국초등과학교육학회지:초등과학교육
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• 제33권2호
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• pp.242-257
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• 2014

Researchers have employed a diversity of definitions and measurement methods for creativity. As a result, creativity research is underrepresented in the literature and the findings of different studies often prove difficult to draw into a coherent body of understanding. With regard to assessment, there are some important problems both in creativity research and practice, such as originality bias and Big-C creativity bias in teachers' perceptions about creativity and creative thinking, and additive rather than multiplicative scoring systems of creativity assessment. Drawing upon most widely accepted conceptions of the creativity construct, I defined 'student's scientific creativity' as the ability to make a product both original and useful to the student in terms of little-c creativity, and 'scientist's scientific creativity' as the ability to come up with a product both original and useful to the science community in terms of Big-C creativity. In this study, an 'Assessment Formula for Scientific Creativity' was developed, which is consisted of the multiplication of originality and usefulness scores rather than the sum of the two scores, and then, with scores calculated from the assessment formula, the scientific explanations generated by children were categorized into four types: routine, useful, original, and creative types. The assessment formula was revealed to be both valid and reliable. The implications of the assessment formula for scientific creativity are examined. The new assessment formula may contribute to the comprehensive understanding of scientific creativity to guide future research and the appropriate interpretation of previous studies.

• 한국재난관리표준학회지
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• 제2권3호
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• pp.39-46
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• 2009

소형루프 전자탐사는 지하매질의 전기비저항 분포를 비파괴적으로 영상화하는 효과적인 탐사방법이다. 하지만, 측정자료에 대한 정량적인 해석과 심도별 단면을 획득하기 위해서는 측정자료의 품질이 매우 중요하다. 본 연구에서는 소형루프 전자탐사 자료 획득 시 주변 배경잡음을 함께 측정하여 정량적 해석을 어렵게 하는 Bias noise를 제거하는 방법을 제시하였다. 이를 통해 잡음의 영향이 크게 감소한 신뢰성 있는 자료를 획득할 수 있었다. 이와 함께 측정자료로부터 전기비저항 영상을 간단하게 산출할 수 있는 겉보기 비저항 산출기법을 제시하였다. 본 연구에서 제시된 방법을 서로 다른 지하수위 조건을 가진 인공 모의지반 실험 사이트에 적용하였으며, 이를 통해 소형루프 전자탐사가 누수와 같이 지하수위 조건이 다른 지역을 탐지하는데 효과적인 방법임을 확인하였다.

• 응용통계연구
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• 제34권2호
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• pp.177-190
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• 2021

랜덤포레스트는 여러 의사결정나무 모형들을 융합하여 안정성과 예측력을 높여주기 때문에 종종 사용되는 방법이다. 예측력을 증가시키는 반면 해석의 용이성을 희생하기 때문에 이를 보상하기 위해 변수의 중요도를 제공한다. 변수의 중요도는 랜덤포레스트를 구축할 때 변수가 얼마나 중요한 역할을 하는지를 알려 준다. 그러나 어떤 예측변수가 다른 예측변수들과 상관되어 있을 때 기존 알고리즘의 변수중요도는 왜곡될 수 있다. 상관된 예측변수들의 하향 편향은 예측변수의 중요도를 실제 중요도보다 낮게 측정하게 한다. 우리는 기존 알고리즘을 수정하여 상관 예측변수의 하향 편향을 회복하는 새로운 알고리즘을 제안한다. 제안된 알고리즘의 성능은 모의 자료에 의해 증명되고 실제 자료에 의해 설명된다.

• 기본간호학회지
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• 제5권2호
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• pp.269-279
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• 1998

In nursing research that the data is collected through clinical observation, analysis of clinical recording or coding of interpersonal interaction in clinical areas, testing and reporting interrater reliability is very important to assure reliable results. Procedures for interrater reliability in these studies should follow two steps. The first step is to determine unitizing reliability, which is defined as consistency in the identification of same data elements in the record by two or more raters reviewing the same record. Unitizing reliability have been rarely reported in previous studies. Unitizing reliability should be tested before progressing to the next step as precondition. Next step is to determine interpretive reliability. Cohen's kappa is a preferable method of calculating the extent of agreement between observer or judges because it provides beyond-chance agreement. Despite its usefulness, kappa can sometimes present paradoxical conclusions and can be difficult to interpret. These difficulties result from the feature of kappa which is affected in complex ways by the presence of bias between observers and by true prevalence of certain categories. Therefore, percentage agreement should be reported with kappa for adequate interpretation of kappa. The presence of bias should be assessed using the bias index and the effect of prevalence should be assessed using the prevalence index. Researchers have been reported only global reliability reflecting the extent to which coders can consistently use the whole coding system across all categories. Category-by-category reliability also need to be reported to inform the possibility that some categories are harder to use than others.

• Bulletin of the Korean Chemical Society
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• 제29권2호
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• pp.438-444
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• 2008

A self-assembled monolayer of 2,2'-bipyridine (22BPY) molecules on Au(111) underwent a structural phase transition when the polarity of a bias voltage was switched in scanning tunneling microscopy (STM) experiments. The nature of two bright spots representing each 22BPY molecule on Au(111) in the high-resolution STM images was identified by calculating the partial density plots for a monolayer of 22BPY molecules adsorbed on Au(111) using tight-binding electronic structure calculations. The stacking pattern of the chains of 22BPY molecules on Au(111) was explained by examining the intermolecular interactions between the 22BPY molecules based on first principles electronic structure calculations for a 22BPY dimer, (22BPY)2. The structural instability of the 22BPY molecule arrangement caused by a change in the bias voltage switch was investigated by estimating the adsorbate-surface interaction energy using a point-charge approximation for Au(111).