• 설비공학논문집
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• 제14권9호
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• pp.725-733
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• 2002

In this study, the heat transport limitations of a two-phase closed thermosyphon were investigated. For the test, a two-phase closed thermosyphon ($L_t/: 600 mm,\;L_e:105mm,\;L_a:75mm,\;L_c:420mm,\;D_o:22.2mm,$ container: copper (inner grooved surface), working fluid: PFC ($C_6F_14$) was fabricated with a reservoir that can change the fill charge ratio. The following was imposed as the factors on the heat transport limitations of a two-phase closed thermosyphon. 1) Fill charge ratio of the working fluid. 2) Tilt angle of the longitudinal axis. From tile experimental data, some results were obtained as follows. When the fill charge ratio was relatively small ($\psi$20%), the heat transport limitation occurred about 100W by dry-out limitation. However over 40%, it shelved nearly constant value (500 W) by flooding limitation. The heat transport limitation according to the tilt angle increased smoothly until the tilt angle was $60^{\circ}$,/TEX>, after then decreased slowly.

• 대한치과의사협회지
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• 제52권8호
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• pp.456-463
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• 2014

Caries Management by Risk Assessment (CAMBRA), published by California Dental Association in 2003, is a customized caries care system that classifies individuals' caries risk into 4 risk groups based on objective evidences and provides chemical treatments targeted for each caries risk level. However, this system was not only developed but also optimized for situation in the United States, resulting into many limitations to be used in Korea, and thus Korean CAMBRA (K-CAMBRA) that considers the clinical situation in Korea needs to be developed. K-CAMBRA includes various techniques that are newly developed in order to overcome the limitations. First, Q-ray, a new optical technology, is utilized in order to avoid the subjectivity of visual inspection during assessment of disease indicators and risk factors. Moreover, Cariview? that reflects the paradigm shift in cariology as a new form of caries assessment kit is used. In addition, considering the situation in Korea, where it is impossible to use high concentration fluoride product, Oral pack with a customized tray is added to increase the contact time of chemical substance. CAMBRA is believed to be the key clinical tool that overcomes the limitations of the paradigm of the conventional restoration-based surgical model of dentistry. Furthermore, it can be expected that Korean dentists can act as oral physicians who are able to control and care individuals' caries risk rather than operative experts who only care about the outcome of caries.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2014년도 춘계학술대회
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• pp.271-272
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• 2014

범죄 수사에서 디지털 증거물이 증가됨에 따라, 법적으로 효용성이 큰 데이터를 추출할 수 있는 디지털 포렌식 도구에 대한 중요성이 높아지고 있다. 디지털 제품들은 빠르게 성장하고 있고, 포렌식 도구는 사용자와 사건에 맞도록 용이하게 구현 되어야 한다. 포렌식 업계나 정부에서는 소요 비용이 큰 포렌식 도구를 사용하고 있지만 메모리 한계, 사후 감사의 한계 등 한계성이 제시되고 있다. 이러한 문제를 해결하기 위하여 다양한 포렌식 도구가 빠르게 구현 할 수 있도록 오픈소스 포렌식 도구 개발이 필요하다. 본 논문에서는 현재 상용화 되고 있는 디지털 포렌식 기술들에 관해 연구하고, 이들의 한계성을 극복하기 위한 오픈 디지털 포렌식 기법들을 제시하고, 적용 방안에 대해 제안한다.

• 한국수학교육학회지시리즈A:수학교육
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• 제58권1호
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• pp.79-99
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• 2019

This study is a study to collect information about 'Limitations of functions' related learning. Especially, this study was conducted on three students who can find answers by algebraic procedure in the process of extreme problem solving. Students have had the experience of converting from their algebraic procedures to graphical expressions. This shows how they reflect on their algebraic procedures. This study is a study that observes these parts. To accomplish this, twelfth were teaching experiment in three high school students. And we analyzed the contents related to the research topic of this study. Through this, students showed the difference of expressions in the method of finding limits by using algebraic interpretation methods and graphs. In addition, we examined the connectivity of the limitations of functions problem solving process of functions using algebraic procedures and graphs in the process of converting algebraic expressions to graph expressions. This study is a study of how students construct limit concepts. As in this study, it is meaningful to accumulate practical information about students' limit conceptual composition. We hope that this study will help students to study limit concept development process for students who have no limit learning experience in the future.

• 한국의사학회지
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• 제31권2호
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• pp.83-90
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• 2018

This study tries to review the possibility of combination between PBL (Problem Based Learning) and Eui'an (醫案). Recently in the field of Korean Medicine, people have been raising issues related to education of Korean Medicine. The point of issue is 'competence centered education of Korean Medicine' which has set the goal of education of Korean Medicine. To achieve the goal, PBL is considered as a very useful tool. But it is considered that there are limitations to direct application of PBL to Korean Medicine. This study aims to lay out the specific reason for the limitations and to search for solutions to overcome the limitations when applying PBL to Korean Medicine. This study suggests that the combination between PBL and Eui'an might be a sound solution to the aforementioned problem.

• Advances in aircraft and spacecraft science
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• 제8권1호
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• pp.1-15
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• 2021

Mars exploration demands aerodynamic computations for a proper design of missions of spacecraft carrying instruments and astronauts to Mars. Both Computational Fluid Dynamics (CFD) and Direct Simulation Monte Carlo (DSMC) method play a key role for this purpose. To the author's knowledge, the altitude separating the fields of applicability of CFD and DSMC in Mars atmosphere entry is not yet clearly defined. The limitations in using DSMC at low altitudes are due to technical limitations of the computer. The limitations in using CFD at high altitudes are due to thermodynamic non-equilibrium. Here, this problem is studied in Mars atmosphere entry, considering the Mars Pathfinder capsule in the altitude interval 40-80 km, by means of a DSMC code. Non-equilibrium is quantified by the relative differences between translational temperature and: rotational (θt-r), vibrational (θt-v), overall (θt-ov) temperatures, anisotropy is quantified by the relative difference between the translational temperature component along x and those along y (θx-y) and along z (θx-z). The results showed that θt-r, θt-v, θx-y, θx-z are almost equivalent. The altitude of 45 km should be the limit altitude for a proper use of a CFD code and the altitude of 40 km should be the limit altitude for a reasonable use of a DSMC code.

• 대한건축학회논문집:계획계
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• 제35권2호
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• pp.93-104
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• 2019

Minimal art, which began to flourish in the mid-1960s, explores perceptual situations caused by the involvement of objects in given site contexts. This has led to the mentions of minimal art as a site-specific art, but its limitations have also been pointed out. This study specifically addresses the limitations of minimal art as a site-specific art with two perceptual points of view. First, according to Michael Fried, situations described as 'now here' focus largely on the bodily experiences of a place. However, they do not rooted in specific time and space of a certain place. Second, the unique characteristics of a certain place are excluded from the perception of the body which occupies the passage of time. Self-sufficient algorithm, which is far from site-specific conditions, is the autonomous system creating the period in the way of arrangement of objects. In addition, Minimal art regards a body only as the objectivity excluding the subjectivity which is essential creating meaning in a place. In the latter part of the article, these features are dealt with through Donald Judd's works. This study on site-specificity also provides a new perspective on the discussion of Minimal architecture and Minimal landscape.

• Earthquakes and Structures
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• 제19권6호
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• pp.471-484
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• 2020

Previous earthquakes show that, structural safety evaluations should include the evaluation of nonstructural components. Failure of nonstructural components can affect the operational capacity of critical facilities, such as hospitals and fire stations, which can cause an increase in number of deaths. Additionally, failure of nonstructural components may result in economic, architectural, and historical losses of community. Accelerations and random vibrations must be under the predefined limitations in structures with high technological equipment, data centers in this case. Failure of server equipment and anchored server racks are investigated in this study. A probabilistic study is completed for a low-rise rigid sample structure. The structure is investigated in two versions, (i) conventional fixed-based structure and (ii) with a base isolation system. Seismic hazard assessment is completed for the selected site. Monte Carlo simulations are generated with selected parameters. Uncertainties in both structural parameters and mechanical properties of isolation system are included in simulations. Anchorage failure and vibration failures are investigated. Different methods to generate fragility curves are used. The site-specific annual hazard curve is used to generate risk curves for two different structures. A risk matrix is proposed for the design of data centers. Results show that base isolation systems reduce the failure probability significantly in higher floors. It was also understood that, base isolation systems are highly sensitive to earthquake characteristics rather than variability in structural and mechanical properties, in terms of accelerations. Another outcome is that code-provided anchorage failure limitations are more vulnerable than the random vibration failure limitations of server equipment.

• 한국IT서비스학회지
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• 제20권3호
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• pp.75-86
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• 2021

As artificial intelligence is actively studied, chatbot systems are being applied to various fields. In particular, many chatbot systems for psychological counseling have been studied that can comfort modern people. However, while most psychological counseling chatbots are studied as rule-base and deep learning-based chatbots, there are large limitations for each chatbot. To overcome the limitations of psychological counseling using such chatbots, we proposes a novel psychological counseling AI chatbot system. The proposed system consists of a GPT-2 model that generates output sentence for Korean input sentences and an Electra model that serves as sentiment analysis and anxiety cause classification, which can be provided with psychological tests and collective intelligence functions. At the same time as deep learning-based chatbots and conversations take place, sentiment analysis of input sentences simultaneously recognizes user's emotions and presents psychological tests and collective intelligence solutions to solve the limitations of psychological counseling that can only be done with chatbots. Since the role of sentiment analysis and anxiety cause classification, which are the links of each function, is important for the progression of the proposed system, we experiment the performance of those parts. We verify the novelty and accuracy of the proposed system. It also shows that the AI chatbot system can perform counseling excellently.

• 한국임상약학회지
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• 제31권4호
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• pp.285-292
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• 2021

Background: Recently, the Korean Association of Pharmacy Education has been focusing on competency-based education (CBE) and has established required areas of competencies to improve the graduation competency. However, competency-based assessment (CBA) tools for implementing CBE have not yet been developed for faculty members and students to successfully access the assessment tests. Moreover, the faculty members in charge in pharmacy schools have encountered various barriers in recruiting individuals with integrated clinical experience to act as virtual patients. Therefore, this study aimed to identify the advantages and limitations of applying CBA tool and faculty assessors in the development of CBE to ensure the reliability of this assessment. Methods: Utilizing CBA tool, the students' communication skills and styles were assessed. students and faculty assessors were surveyed to evaluate the advantages and limitations of the CBA tool. Results: 8 assessors and 96 students participated in this study. 100% (8/8) of the faculty assessors and 77.4% (65/84) of the students reported that CBA tool is valuable to assess and improve student's ability. 90.5% (76/84) of the students felt confident in applying knowledge to patient-centered care. CBA tool can be a valuable for the instructors in identifying the competency level of students but can also be associated with limitations in implementation to ensure the objectivity and reliability of the CBA. Conclusions: The CBA tool can be valuable in assessing the level of students' competency. Faculty assessors have the advantage of well-prepared themselves for patient roles, so that the time and cost required may be minimized.