• Journal of Astronomy and Space Sciences
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• 제31권4호
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• pp.285-294
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• 2014

The uneven mass distribution of the Moon highly perturbs the lunar spacecrafts. This uneven mass distribution leads to peculiar dynamical features of the lunar orbiters. The critical inclination is the value of inclination which keeps the deviation of the argument of pericentre from the initial values to be zero. Considerable investigations have been performed for critical inclination when the gravity field is assumed to be symmetric around the equator, namely for oblate gravity field to which Earth's satellites are most likely to be subjected. But in the case of a lunar orbiter, the gravity field of mass distribution is rather asymmetric, that is, sectorial, and tesseral, harmonic coefficients are big enough so they can't be neglected. In the present work, the effects of the first sectorial and tesseral harmonic coefficients in addition to the first zonal harmonic coefficients on the critical inclination of a lunar artificial satellite are investigated. The study is carried out using the Hamiltonian framework. The Hamiltonian of the problem is cconstructed and the short periodic terms are eliminated using Delaunay canonical variables. Considering the above perturbations, numerical simulations for a hypothetical lunar orbiter are presented. Finally, this study reveals that the critical inclination is quite different from the critical inclination of traditional sense and/or even has multiple solutions. Consequently, different families of critical inclination are obtained and analyzed.

• 정보관리학회지
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• 제25권1호
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• pp.19-41
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• 2008

논문기사의 비평적 초록을 웹 환경 아래서 자동으로 생성하기 위하여 비평 단서어구, 비평 정보 범례, 비평 수록 문장 발췌규칙, 비평문장 생성규칙을 작성하였다. 비평 정보를 발췌하고 문장을 생성하는데 필요한 비평문 작성 도움 온톨로지를 만들어 비평의 단초가 되는 단서어구와 문장 간의 징후들을 관리 운영하였다. 징후들은 원문의 연구목적, 방법, 결과, 결론 문장을 중심으로 그 주변 문장들에서 상호 작용하여 표출되는 문맥적 정보를 이용하였다. 실제 비평문장의 성능을 조사한 결과, 발췌 및 생성 규칙의 개선과 온톨로지의 관계들이 보강되어야 할 것으로 판단하였다.

• 대한수학회지
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• 제55권3호
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• pp.623-669
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• 2018

In Donaldson-Thomas theory, moduli spaces are locally the critical locus of a holomorphic function defined on a complex manifold. In this paper, we develop a theory of critical virtual manifolds which are the gluing of critical loci of holomorphic functions. We show that a critical virtual manifold X admits a natural semi-perfect obstruction theory and a virtual fundamental class $[X]^{vir}$ whose degree $DT(X)=deg[X]^{vir}$ is the Euler characteristic ${\chi}_{\nu}$(X) weighted by the Behrend function ${\nu}$. We prove that when the critical virtual manifold is orientable, the local perverse sheaves of vanishing cycles glue to a perverse sheaf P whose hypercohomology has Euler characteristic equal to the Donaldson-Thomas type invariant DT(X). In the companion paper, we proved that a moduli space X of simple sheaves on a Calabi-Yau 3-fold Y is a critical virtual manifold whose perverse sheaf categorifies the Donaldson-Thomas invariant of Y and also gives us a mathematical theory of Gopakumar-Vafa invariants.

• 중환자간호학회지
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• 제11권2호
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• pp.1-10
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• 2018

Purpose : This study aimed to develop an in-depth and comprehensive understanding of the experiences of critical care nurses caring for dying patients. Method : Eleven critical care nurses with experience in caring for dying patients were recruited from four tertiary hospitals. Semi-structured face-to-face interviews were conducted between November 2016 and March 2017. The transcribed data were analyzed using qualitative content analysis to identify major themes and sub-themes that represented the experiences of critical care nurses. Results : The following six themes, and twelve sub-themes, were identified: (1) the gap between expectation and reality, (2) a distorted meaning of death, (3) repeated emotional pain and stress, (4) finding a solution alone, (5) sublimation into mission and calling, and (6) integration into one's own life. Conclusion : This study found that critical care nurses experience various psychological difficulties while caring for dying patients, and they made efforts on their own to overcome them. These findings are expected to inform the development of specialized programs to support critical care nurses to tackle these challenges, create guidelines on caring for dying patients, and help promote death education.

• 중환자간호학회지
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• 제9권2호
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• pp.36-47
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• 2016

Purpose: The study examined core job characteristics and job preference to explain work performance among critical care nurses. The theoretical model was constructed based on the job characteristics model with core job characteristics as exogenous variables, and work performance and job preference as endogenous variables. Methods: A total of 228 hospital nurses participated in the study from May to September, 2015. Data were collected through structured questionnaires and analyzed using structural equation modeling. Results: The model showed a good fit to the data with $x^2/df=2.90$, goodness of fit index = .91, root mean square residual = .20, comparative fit index = .93, and incremental fit index = .93. The core job characteristics explained 64% of the variance in job preference. The core job characteristics and job preference explained 52% of the variance in work performance. Conclusions: The core job characteristics can explain the work performance among critical care nurses through job preference. Effective strategies to improve the work performance among critical care nurses should focus on the application of the core job characteristic into a productive work environment. Further studies are warranted to explore the role of job preference of critical care nurses in promoting their work performance.

• 한국수학교육학회지시리즈A:수학교육
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• 제53권3호
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• pp.413-434
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• 2014

Logic lays the foundation of Mathematics and the development of Mathematics is dependent on critical thinking. So it is important that school mathematics helps students develop their logical and critical thinking ability for both mathematics learning and problem solving in general. MINDSTORMS, a LEGO based programming activity kit, is an effective teaching and learning tool that can be used to enhance logical and critical thinking in students. This study focused on measuring the growth of students' ability to think logically and critically when they used MINDSTORMS activities to learn programming. In addition, we investigated how the students' logical and critical thinking changed from the MINDSTORMS learning experience. The study confirmed that the programming activities using MINDSTORMS help to enhance logical and critical thinking in students. The students attitude about logical and critical thinking became more positive and the activities helped to engage students to think logically and critically. This type of programming activities should be valuable in mathematics education and it should be included in a general mathematics curriculum.

• 문화기술의 융합
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• 제2권2호
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• pp.9-15
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• 2016

Objectives : The purpose of this study to investigate the Critical Thinking disposition in Nursing College students and related to ability of basic nursing science. Methods : Data were collected from 36 students who were students belong to one of province University. The instrument used in this study was California Critical Thinking Disposition Inventory(CCTDI) by Facione & Facione. The instrument was composed of 7 sub-items, truth-seeking, analyticity, systematicity, open-mindness, critical thinking, self-confidence, inquisitiveness, and maturity. The data were analyzed by descriptive statistics, t-test, ANOVA, Pearson Correlations with SPSS 12.0. Results : The result of this study were as follow; The average of total score in critical thinking disposition was 44.8, which means middle level(below 40: low, above 50: high level). Maturity was the highest while open-mindness was the lowest with an average score 5.01. There was significant difference between critical thinking and basic nursing science grade while there was no difference between age, gender, and religion. There was strongly relation between critical thinking disposition and basic nursing science(F=2.84, p=.01). Conclusion : According to the results of this study, nursing curriculum should be considered critical thinking disposition.

• International Journal of Internet, Broadcasting and Communication
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• 제10권2호
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• pp.60-67
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• 2018

The purpose of this study was to examine the effects of internet-use Anatomy class, as one of the Flipped learning method, on critical thinking disposition. The class for this study was conducted from March 1 to April 10, 2018. The study involved a total of 180 people in the first year of a University located in C province. Data collection was carried out before and after the Flipped learning method application. Frequency analysis, Paired t-test, Pearson correlation, and Regression analysis were used for the analysis. According to the analysis, 28.3% of men and 71.1% of women and before applying the program analysis of correlation between Flipped learning perception and critical thinking disposition showed a significant correlation between confidence(sub-component of critical thinking) only (p<.005). Comparing the scores of critical thinking before and after the program, it was found that Truth seeking (p<.001), Open-mindness (p<.005), Confidence (p<.001), Systematicity (p<.005), Analyticity (p<.001), and Inquisitiveness (p<.001) scores had increased significantly except Maturity (p>.005). And the regression analysis of Flipped learning method applying influence on critical thinking disposition were significantly affected (p<.001). Based on the results of this study, it was possible to determine that Flipped learning method had a positive effect on critical thinking disposition.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권7호
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• pp.424-429
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• 2004

The 4-probe method with a voltage tap on terminals has been used for the measurement of the critical current of multi-strand high-T$_{c}$ superconducting(HTS) cables. And the critical current of cables is obtained as the measured total current divided by the number of conductor when the terminal voltage exceeds the predetermined criterion of critical current. However, because of the non-uniform current distribution due to the different critical current, shapes, and other characteristics of each conductor, this is not applicable method to the multi-strand HTS cable. To determine the critical current of multi-strand HTS cable, the critical current of each conductor must be measured with different method. h this paper, the current distribution and the critical current of each conductors in multi-strand cable were measured with specially made Pick-up coils and voltage taps. It is presented that the real critical current of multi-strand is smaller than sum of each conductors. The main cause of non-uniform current distribution is the difference between the resistances appeared in each HTS wires.s.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 추계학술대회 논문집
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• pp.254-259
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• 2003

The 4-probe method with a voltage tap on terminals has been used for the measurement of the critical current of multi-strand high-Tc superconducting (HTS) cables. And the critical current of cables is obtained as the measured total current divided by the number of conductor when the terminal voltage exceeds the predetermined criterion of critical current. However, because of the non-uniform current distribution due to the different critical current, shapes, and other characteristics of each conductor this is not applicable method to the multi-strand HTS cable. To determine the critical current of multi-strand HTS cable the critical current of each conductor must be measured with different method. In this paper, the current distribution and the critical current of each conductor in multi-strand cable were measured with specially made pick-up coils and voltage taps. It is presented that the real critical current of multi-strand is smaller than sum of each conductors. The main cause of non-uniform current distribution is the different resistances appeared in each HTS wires.