• Bulletin of the Society of Naval Architects of Korea
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• v.26 no.3
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• pp.9-20
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• 1989

It is important to enhance the safety of ship structures as much as possible in order to prevent the disastrous collapse of structures. In fact, the strength problem of structures is closely related with the safety problem of structures. Recently, the direct calculation method using a rational approach based on the first principle is implemented into the structural design process instead of adopting empirical approach based on the rules. The structural designer have shown increased concern with the problem of adequacy of conventional design method based on the safety factor since it does not fully take into account some degree of variability of the applied loads on and the strength of ship structures. To deal with the analysis of structures effectively, it is necessary to have three stages being equally treated. The first one is load analysis, second one response analysis, third one safety analysis. For marine structures, most of research effort has been however put into the first and second stages. The third stage is normally done by simple procedures. Hence, the various probabilistic methods are compared in order to establish the reliability analysis techniques for ship structures. As a result, the advanced level 2 method is selected as a most effective and accurate reliability method. The validity of this method is further demonstrated by comparing the results with the conventional method for the problem of the longitudinal strength of hull girder of Ro-Ro ship.

• Journal of Science Education
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• v.39 no.2
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• pp.267-277
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• 2015

This study explored elementary school teachers' perspectives on science inquiry teaching. First, an open-ended questionnaire was administered to elicit teachers' experiences of their approach to inquiry teaching. These self-reported approaches revealed three conceptions of teaching for inquiry learning in science: 'science process skills-centered' category focused on observing, classifying, measuring, and fair testing; 'generating scientific questions' category focused on students' question-generating; and 'illustrate concept and/or content' category focused on science content demonstration by making use of experimental procedures to obtain expected results. Second, teachers were asked to place 18 activity cards either close to or further from an 'inquiry-based science classroom' card. The relative distances from the activity card to the central classroom card were measured. The teachers perceived that students' activity of 'designing and implementing appropriate procedures' was the most important in supporting an inquiry-based science classroom. Understanding teachers' views has implications for both the enactment of inquiry teaching in the classroom as well as the uptake of new teaching behaviors during professional development.

• The Journal of the Korea Contents Association
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• v.16 no.4
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• pp.614-623
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• 2016

Grid(pipe network) design is an important element of Smart Water Grid, which essential to estimate hydraulic parameters such as the pressure, friction factor, friction velocity, head loss and energy slope. Especially, friction velocity in a grid is an important factor in conjunction with energy gradient, friction coefficient, pressure and head loss. However, accurate estimation friction head loss, friction velocity and friction factor are very difficult. The empirical friction factor is still estimated by using theory and equation which were developed one hundred years ago. Therefore, in this paper, new equation from maximum velocity and friction velocity is developed by using integration relationship between Darcy-Weisbach's friction head loss equation and Schlichting equation and regression analysis. To prove the developed equation, smooth pipe data areis used. Proposed equation shows high accuracy compared to observed data. Study results are expected to be used in stability improvements and design in a grid.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.4
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• pp.2868-2875
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• 2015

Both the friction velocity and the friction coefficient have to be estimated to determine flow characteristic in an open channel. In spite of the importances in an open channel, the complete interpretation is highly difficult because of free water surface, the complex of cross section and the various hydraulic parameters. The researches related to the friction factor are based on empirical outcome. Therefore, the equations are difficult to be generally applied. For that reason, the new friction factor estimation equation using the entropy concept was proposed in the present study, and the data measured in rectangular and trapezoid cross sections was used to verify the accuracy of equation. The advantage of the proposed equation dose not use the energy slope term which is difficult to be measured and to be estimated in an open channel. In addition, the proposed method showed that the accurate friction factor f can be estimated on the Basis of theoretical background.

• Journal for History of Mathematics
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• v.21 no.2
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• pp.81-90
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• 2008

It has been noticed the greater importance of mathematical education, particularly of multi-variable calculus in the undergraduate level with remarkable progress of all sorts of sciences requiring mathematical analysis. However, there was lack of variety of introducing the definition of differentiation of multi-variable functions - in fact, all of them basically rely on the chain rules. Here we will introduce a way of defining the geometrical differentiation of the multi-variable functions based upon our teaching experience. One of its merits is that it provides the geometric explanation of the differentiation of the multi-variable functions, so that it conveys the meaning of the differentiation better compared with the known methods.

• Journal of Chest Surgery
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• v.31 no.3
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• pp.319-323
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• 1998

Thymic carcinoid tumor is a rare mediastinal tumor, which was firstly described by Rosai and Higa in 1972. A carcinoid tumor of the thymus has recently been regarded as a distinct tumor from thymoma, and is probably Kultschizky cell origin. The pathologic diagnosis of thymic carcinoid is made from findings from light microscopy, immunohistochemical studies and electron microscopy. About 50% of thymic carcinoids were seen with endocrinopathies. Recurrences and extrathoracic metastasis are characteristics of thymic carcinoids. Surgical removal of the intial and tumor recurred are considered to be the most effective treatment today. However, the role of the adjuvant radiotherapy and the chemotherapy is still uncertain. Herein we report a case of thymic carcinoid tumor, which was confirmed by operation and pathologic study.

• 기호학연구
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• no.54
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• pp.7-36
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• 2018

Michael Polanyi's idea of tacit knowledge came from the realization that scientific objectivity and critical philosophy had become too restrictive for philosophy, especially in the realm of meaning, which is beyond positivistic proof and contains more non-critical elements than critical ones. In social life, people still share certain kinds of knowledge and beliefs which they obtain without making or learning those explicitly. Contemplating the role and significance of tacit knowledge, he called for a post-critical philosophy that integrates the realm of meaning and thereby appreciates the intertwined nature of tacit and explicit knowledge. Polanyi's position towards skepticism and doubt shows similarities with Charles S. Peirce's thinking about the relationship between belief and doubt. Although Peirce's semeiotics stands firmly in the tradition of critical philosophy, he affirms that doubt cannot be a constant state of mind and only belief can form a basis for a specific way of life. Polanyi's approach differs from Peirce's by focusing on the impossibility of scientific knowledge based solely on principles and precision, and his emphasis on the crucial role of the community of scientists. Nevertheless, the deeper implications of Peirce's contemplations on belief and doubt have myriad ramifications on the philosophy of science as well as the sociology of science.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.692-699
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• 2017

The purpose of this study is to investigate the display fatigue quantitatively when operating 2D and HMD-based 3D VR bicycles. Though it is generally accepted that the display fatigue induced by 3D VR is greater than that induced by 2D VR, there have been few studies which attempted to measure the display fatigue scientifically. The subjective degree of cybersickness and quantitative flicker fusion frequency (FFF) were measured in twenty subjects (Male 10, Female 10) before and after they operated 2D and 3D VR bicycles for 5 min. Two dependent variables affected by the 2D and 3D VR displays were analyzed and compared statistically based on scientific evidence and research. This study showed that 3D VR resulted in a significantly higher cybersickness rate and a significant lower FFF rate than 2D VR. Given the current propensity to couple VR techniques with exercise equipment, it seems appropriate to verify the general beliefs through scientific methods and experimental measures such as the FFF and cybersickness questionnaires.

• Journal of the Korean Society for Library and Information Science
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• v.17
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• pp.203-227
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• 1989

본 연구의 목적은 유사한 문화적 배경을 공유한 일본, 한국, 대만의 도서관학 교육을 비교하여 유사점과 상이점을 발견하고 그들의 배경이유를 찾아서 사회와 도서관학 교육의 관계를 밝히는 것이다. 비교의 대상이 된 교육기관은 4년제 대학(교)의 도서관학과로 일본의 다섯 대학교, 한국의 아홉 대학교, 대만의 네 대학교의 도서관학 교육을 비교하였다. 연구가 증명하려고 시도한 가설은, 1. 일본, 한국, 대만은 유사한 문화적 배경을 공유하는 한편, 미국의 도서관학 교육을 받아들였으므로, 세 나라의 도서관학 교육에는 유사점들이 있을 것이다. 2. 상이점들이 있다면, 그것들은 각 국의 특성을 반영할 것이다. 3. 세 나라의 도서관학 교육에 유사점들이 있다면 도서관학 교육의 경향, 문제점들 및 전망도 비슷할 것이다. 가설의 증명을 위하여 교육의 목적, 교수진, 남$\cdot$여학생의 비율, 입학시의 학생들의 학력수준, 교과과정, 과정수료에 요구되는 특수조건, 교과서, 연구, 학과 도서실 및 시설, 학과와 도서관과의 협력관계, 정보학 교과목, 사회가 요구하는 도서관 봉사 및 그에 대응하는 도서관학 교육의 청도, 교육의 경향, 문제점 및 장래 그리고 학과 졸업생들의 도서관 취업률 등을 비교하였다. 비교의 결과 가설을 타당한 것으로 받아들일 수 있었다. 결론에 대한 설명과 아울러 도서관학 교육의 방향을 제언하였다. 1. 미국의 도서관학 교육이 근거로 한 이론적인 배경 및 개념을 재검토하여 적합한 것은 받아들이고, 필요한 경우에는 변형하여 적용하도록 노력해야 한다. 미국과 다른 나라의 실제 도서관 업무 및 봉사에 대한 이해를 토대로 하여 사서와 교육자가 함께 자국의 상황에 적합한 고유한 도서관학을 정립하여야 한다. 2. 도서관 이용 및 봉사에 보다 관심을 기울이고 바람직한 개념을 홍보하고 그것에 호응하는 환경을 만들기 위하여 노력해야 한다. 미래의 사서인 학생들을 이용자에게 접근하여 그들을 가르칠 수 있고 도서관을 이용하도록 유도할 수 있게끔 교육을 시켜야 할 것이다. 3. 미국 이외의 나라에서 실시되는 교육제도에도 관심을 가져야 할 것이다. 4. 도서관 및 도서관학 교육에 정부의 적극적인 지원이 필요하다. 다른 전문직과 같은 대우를 받으려면, 국가고시제도가 도입되어야 할 것이다. 5. 도서관협회가 도서관학 교육에 보다 적극적으로 참여해야 한다. 사서 자격증을 관할하는 단체가 될 수도 있고 교육의 내용에도 관여할 수 있다. 6. 도서관학과와 도서관과의 협력관계가 보다 강화되어야 하며, 도서관현장을 토대로 한 연구활동이 필요하다. 진정한 의미의 문제 해결을 위한 연구활동이 없이 이론적, 실제적인 발전을 기대할 수 없다. 7. 대학(교) 도서관 및 특수도서관의 사서를 위한 전문교육은 대학원 수준에서 제공되고, 학부의 도서관학 교육은 학교도서관 및 공공도서관의 사서를 위한 교육으로 전문화되어야 한다. 8. 도서관학의 교육자들이 모여 문제를 토론하고 해결책을 모색할 수 있는 기회가 제공되어야 하며, 세 나라가 공동의 경험을 나누고 문제를 함께 해결할 수 있는 공식적인 회의나 학회의 구성이 필요하다.

• Korean Journal of Social Welfare
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• v.66 no.3
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• pp.5-28
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• 2014

School absenteeism, one of the early warning signs of behavioral problems, has been known to be a complex and heterogeneous problem. However, much of the research assumes that school absentee adolescents comprise a homogeneous group. This study explored the heterogeneity of school absentee adolescents, based on school adaptation, to provide a more nuanced understanding of school absenteeism and examined predictive and risk factors associated with each typology of school absentee adolescents. Latent profile analysis was conducted using sample 477 middle school students who were reported absent in the previous year from the 3rd wave of Korean Children and Youth Panel Study. Multinomial logistic regression and ANOVA was also employed to examine the effects of predictive variables. As a result, three profiles were identified: low, middle, and high adaptive group. Group membership was found to be associated deferentially with gender, mental health, parenting neglect, delinquent friends, and delinquent behaviors. These findings propose more specific and targeted interventions designed to meet the needs and risk factors associated with the different typologies of school absentee adolescents.