• The Korean Journal of Ceramics
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• 제3권1호
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• pp.5-12
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• 1997

Charged carbon clusters which are formed by the gas activation are suggested to be responsible for the formation of the metastable diamond film. The number of carbon atoms in the cluster that can reverse the stability between diamond and graphite by the capillary effect increases sensitively with increasing the surface energy ratio of graphite to diamond. The gas activation process produces charges such as electrons and ions, which are energetically the strong heterogeneous nucleation sites for the supersaturated carbon vapor, leading to the formation of the charged clusters. Once the carbon clusters are charged, the surface energy of diamond can be reduced by the electrical double layer while that of graphite cannot because diamond is dielectric and graphite is conducting. The unusual phenomena observed in the chemical vapor deposition diamond process can be successfully approached by the charged cluster model. These phenomena include the diamond deposition with the simultaneous graphite etching, which is known as the thermodynamic paradox and the preferential formation of diamond on the convex edge, which is against the well-established concept of the heterogeneous nucleation.

• 예술인문사회 융합 멀티미디어 논문지
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• 제8권8호
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• pp.845-852
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• 2018

마이어-쉔베르거와 쿠키어(Mayer-Schönberger and Cukier, 이하 MSC)는, 빅 데이터의 세계에서는 인과성보다 상관성이 실용적으로 더 유용하고 효율적이라고 주장한다.[4] 더 나아가, 빅 데이터의 세계에서는 인과성에 토대한 분석이나 예측이 상관성에 토대한 분석이나 예측에 밀려 주목받지 않거나 도태될 것이라 주장한다. 이 글에서 필자는, 상관성이 빅 데이터의 현상을 분석하고 이를 토대로 미래를 예측하는 데에 충분하다는 MSC의 논증들을 비판적으로 검토한다. 2장에서는 빅 데이터의 세계에서 상관성이 우월하다는 MSC의 논증을 소개한다. 3장에서는 상관성은 그 자체만으로 충분히 실용적이고 유용하다는 MSC의 논증을 비판한다. 상관성과 인과성의 차이에 대한 오해를 지적하고 심슨(Simpson) 역설로 그 차이가 왜 중요한지를 보여준다. 4장에서는 빅 데이터 분석에서 인과성이 상관성보다 비효율적이라는 MSC의 논증을 비판한다. 특별히 인과성을 증명하는 수학적 방법이 없다는 주장의 오류를 보여준다. 구조방정식에 토대한 인과 모형의 수학적 이론들을 제시하고, 이들 이론으로 인과성이 빅 데이터 분석에서 매우 유의미하고 유용한 역할을 할 수 있다는 것을 보여준다.

• Tuberculosis and Respiratory Diseases
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• 제87권2호
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• pp.176-184
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• 2024

Background: Results of studies investigating the association between body mass index (BMI) and mortality in patients with coronavirus disease-2019 (COVID-19) have been conflicting. Methods: This multicenter, retrospective observational study, conducted between January 2020 and August 2021, evaluated the impact of obesity on outcomes in patients with severe COVID-19 in a Korean national cohort. A total of 1,114 patients were enrolled from 22 tertiary referral hospitals or university-affiliated hospitals, of whom 1,099 were included in the analysis, excluding 15 with unavailable height and weight information. The effect(s) of BMI on patients with severe COVID-19 were analyzed. Results: According to the World Health Organization BMI classification, 59 patients were underweight, 541 were normal, 389 were overweight, and 110 were obese. The overall 28-day mortality rate was 15.3%, and there was no significant difference according to BMI. Univariate Cox analysis revealed that BMI was associated with 28-day mortality (hazard ratio, 0.96; p=0.045), but not in the multivariate analysis. Additionally, patients were divided into two groups based on BMI ≥25 kg/m² and underwent propensity score matching analysis, in which the two groups exhibited no significant difference in mortality at 28 days. The median (interquartile range) clinical frailty scale score at discharge was higher in nonobese patients (3 [3 to 5] vs. 4 [3 to 6], p<0.001). The proportion of frail patients at discharge was significantly higher in the nonobese group (28.1% vs. 46.8%, p<0.001). Conclusion: The obesity paradox was not evident in this cohort of patients with severe COVID-19. However, functional outcomes at discharge were better in the obese group.

• 공학교육연구
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• 제19권4호
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• pp.72-82
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• 2016

In Korea, engineering education based on industry demand is highly emphasized; the survey of industry demand or company satisfaction is frequently conducted. Although engineering schools have often attempted and implemented the reform of engineering education, it was found that company satisfaction with college education was always low. In this context, this study aimed to find the cause of the low satisfaction. To this end, the social background for the active survey of industry demand and company satisfaction, and its progress were investigated. The findings of this study showed that the survey of industry demand in Korea has limitations in improving the quality of college education or developing its future demand, contrary to its intention. This industry demand based approach has its historical and social root in the Korea-specific model of the catching-up style industry development and technology innovation. Therefore, it is difficult to establish appropriate academy-industry relations and discover future vision based on this model. This study presents a new way to understand and develop the future-oriented industrial and social demand, not just arguing for the uselessness of the survey of industry demand in engineering education.

• 한국문헌정보학회지
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• 제35권3호
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• pp.79-92
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• 2001

본 연구에서는 정보사회에서의 정보문제와 정보교육의 문제를 체계와 생활세계라는 사회과학의 상호 경쟁적 패러다임을 통해서 분석하였다. 정보문제와 관련해서는 정보와 정보기술의 패러독스, 기회의 패러독스, 정보의 참조문제와 타당성문제가 다루어졌으며, 정보교육과 관련해서는 정보자주성과 정보소양이 논의되었다. 본 연구의 결론은 정보교육이 개인적 정보문제의 합리적 해결과 사회적 정보문제의 합리적 통제 사이의 갈등 현상을 치유하기 위한 문화적 중재요청이라는 것이다. 그리고 정보교육의 목표는 지식 자주성이 아니라 정보 자주성이어야 하며, 정보 자주성은 컴퓨터소양이 아니라 정보소양을 통해 형성된다는 점이 강조되었다.

• Advances in biomechanics and applications
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• 제1권2호
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• pp.85-93
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• 2014

In this paper, two procedures of enumerating the axial rotation are proposed using the unit sphere of the spherical rotation coordinate system specifying 3D rotation. If the trajectory of the movement is known, the integration of the axial component of the angular velocity plus the geometric effect equal to the enclosed area subtended by the geodesic path on the surface of the unit sphere. If the postures of the initial and final positions are known, the axial rotation is determined by the angular difference from the parallel transport along the geodesic path. The path dependency of the axial rotation of the three dimensional rigid body motion is due to the geometric effect corresponding to the closed loop discontinuity. Firstly, the closed loop discontinuity is examined for the infinitesimal region. The general closed loop discontinuity can be evaluated by the summation of those discontinuities of the infinitesimal regions forming the whole loop. This general loop discontinuity is equal to the surface area enclosed by the closed loop on the surface of the unit sphere. Using this quantification of the closed loop discontinuity of the axial rotation, the geometric effect is determined in enumerating the axial rotation. As an example, the axial rotation of the arm by the Codman's movement is evaluated, which other methods of enumerating the axial rotations failed.

• 한국해양공학회지
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• 제22권1호
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• pp.46-52
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• 2008

Lately Gun-Jang Harbor has undergone a drastic change in hydraulic characteristics due to newly added harbor protection measures, like a wharf and breakwater. The wharf and breakwater, with a training dike, were constructed to keep enough depth far navigation. They make the plan view of Gun-Jang Harbor semi closed and very elongated, which makes it very vulnerable to seiche. Hence it is an urgent task to unveil the hydraulic characteristics, like seiche, for the optimal operation of the new harbor system. In this study, we numerically analyze the seiche characteristics of Gun-Jang Harbor over the $10-4{\sim}10-3$ Hz frequency range, considering that wind waves due to seasonal winds are the most prevailing during winter in the West sea. As a wave driver, we use Mild Slope Eqs. and numerically integrate these using FEM based on Galerkin weak formulation. It turns out that the 1st, 2nd, 3rd and 4th eigen models are over 0.0009 Hz, 0.0013 Hz, 0.0017 Hz and 0.002 Hz.

• 영어영문학
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• 제58권6호
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• pp.1063-1083
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• 2012

Florence Nightingale is best remembered today as the Lady with the Lamp, but modern research on the English nurse primarily addresses her popular iconography as a historical misrepresentation of her character and career. This scholarly reluctance to analyze critically Nightingalean iconography, however, has obscured important cultural work performed by the popular tropes. This article argues that the proliferation of Nightingale's iconic image as a symbol of Christian womanhood in transatlantic periodical poetry, when examined separately from biographical considerations, reveals important insights into the complex relationship between form and affect in mid-nineteenth periodicals. Popular representations of Nightingale give form to the disorienting effects produced on newspaper readers by the nascent field of international journalism and reflect a key generic paradox at the heart of the Victorian periodical: the simultaneous aim to report news objectively and to move readers affectively in response to events beyond national contexts and interests. Focusing on Lewis Carroll's "The Path of Roses" and Henry Wadsworth Longfellow's "Santa Filomena," this article contends that Nightingalean periodical poetry mirrors back to readers their own affective response to modern media and functions as a new technology for managing an increasingly acute awareness of events and ethical responsibilities beyond the nation.

• 우주기술과 응용
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• 제3권4호
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• pp.342-354
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• 2023

뉴스페이스 패러다임에서 바라본 큐브위성 개발과정의 역설은 복잡하고 험난한 시스템 엔지니어링 절차와 관련이 있다. 상업적 관점에서 큐브위성은 비용 측면은 물론 제작 기간도 짧아 스타트업 주도의 뉴 스페이스 산업구조에서 접근성이 뛰어난 우주자산이다. 하지만 큐브위성 경연대회와 같이 대학 주체의 개발팀들이 마주할 개발과정은 생각과는 너무도 다르다. 이는 큐브위성 또한, 시스템 공학기반의 체계사업이 제시하고 있는 길고도 험난한 과정을 통해 위성을 개발하고 검증받기 때문이다. 따라서 본 논문에서는 체계사업에 익숙하지 않은 개발자들에게 큐브위성의 각 개발 단계에 적용되는 시스템공학의 역할과 기능을 전달하고자 한다.

• 한국산학기술학회논문지
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• 제20권10호
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• pp.236-242
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• 2019

최근 유지보수 등의 목적으로 다양한 건설 및 건축 분야에서 스캔 프로젝트가 수행되고 있다. 스캔된 결과로 생선된 포인트 클라우드는 스캔 대상물을 표현하는 수많은 점들로 구성되어 있다. 이런 스캔 데이터에서 치수를 포함한 필요한 정보를 추출하는 과정을 역설계라 한다. 포인트 클라우드를 BIM으로 모델링하는 역설계 과정은 수많은 수작업이 포함되어 있다. 시간이 많이 소모되는 역설계 작업 특성상 설계변경 같은 재작업 요청이 발생되면 비용은 기하급수적으로 증가한다. 역설계 자동화 기술이 이런 문제를 개선하는 데 도움을 줄 수 있다. 하지만, 역설계 산출물은 유스케이스에 따라 가변성을 가지며, 산출물의 종류와 상세수준은 달라질 수 있다. 이런 점을 고려해, 본 연구는 건축물 평면객체 기본 형상(primitive geometry)에서 BIM객체로 자동 맵핑하는 G2BM(Geometry-to-BIM mapping) 규칙 정의 방법을 제안한다. G2BM는 사용자 활용사례 가변성을 고려한 건축물 평면 BIM객체 역설계 프로세스 정의와 사용자화 방안을 제안한다. 그리고, 프로토타입을 통해 이에 대한 효과를 확인한다.