• Structural Engineering and Mechanics
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• 제21권4호
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• pp.407-422
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• 2005

Plate elements in fully profiled sandwich panels are generally subjected to local buckling failure modes and this behaviour is treated in design by using the conventional effective width method for plates with a width to thickness (b/t) ratio less than 100. If the plate elements are very slender (b/t > 1000), the panel failure is governed by wrinkling instead of local buckling and the strength is determined by the flexural wrinkling formula. The plate elements in fully profiled sandwich panels do not fail by wrinkling as their b/t ratio is generally in the range of 100 to 600. For this plate slenderness region, it was found that the current effective width formula overestimates the strength of the fully profiled sandwich panels whereas the wrinkling formula underestimates it. Hence a new effective width design equation has been developed for practical plate slenderness values. However, no guidelines exist to identify the plate slenderness (b/t) limits defining the local buckling, wrinkling and the intermediate regions so that appropriate design rules can be used based on plate slenderness ratios. A research study was therefore conducted using experimental and numerical studies to investigate the effect of plate slenderness ratio on the ultimate strength behaviour of foam supported steel plate elements. This paper presents the details of the study and the results.

• 대한물리의학회지
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• 제13권3호
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• pp.121-132
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• 2018

PURPOSE: This study was conducted to investigate the effects of type of exercise on neck disability, pain, and postural changes in subjects with forward head posture. METHODS: Two independent researchers conducted a search using KISS, RISS, DBpia (domestic), PubMed, OVID, and Science Direct (overseas) databases. We selected randomized controlled clinical trials by searching using the terms "forward head posture", "exercise therapy", and "therapeutic exercise". Studies published from 2007 to December 2017 were included. PEDro Scale was used to evaluate the quality of the selected studies, and meta-analysis was conducted using the CMA program. This review was registered at PROSPERO (CRD42018068633). RESULTS: Of the total 13768 studies searched, 17 were selected. Positive effects on neck disability were achieved with the base and biomechanical elements (ES=1.63, 95% confidence interval [CI] .49 to 2.75) as well as base, modulator, and biomechanical elements (ES=1.50, 95% [CI] .69 to 2.30). Neck pain improved with the base, modulator, and biomechanical elements (ES=1.96, 95% [CI] 1.08 to 2.82), while postural changes improved with biomechanical elements (ES=1.45, 95% [CI] .64 to 2.25). Additionally, type of exercise had a positive effect. CONCLUSION: The most effective exercises for neck disability are of the base and biomechanical elements, while the most effective types for neck pain are of the base, modulator, and biomechanical elements and the most effective exercise for posture is of biomechanical elements. Combined exercises targeting biomechanical elements were effective at treating disability, pain, and postural changes.

• 품질경영학회지
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• 제49권4호
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• pp.447-466
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• 2021

Purpose: This article aims 1) to propose Quality 4.0 concept through surveying related literature, 2) to suggest key elements of Quality 4.0 by arranging the elements of Quality 4.0 that appeared in the literature, 3) to determine the levels of Quality 4.0, and 4) to suggest ideas for effective deployment of Quality 4.0. Methods: Eleven papers or documents are reviewed for Quality 4.0 concept; two papers and one document are investigated for key element extraction of Quality 4.0; and smart factory roadmap and industry 4.0 maturity model are studied to determine the levels of Quality 4.0. Results: 1) Quality 4.0 definition is proposed. 2) Three key elements are determined: data acquisition and analytics, connection and integration, and leadership and culture. 3) Six Quality 4.0 levels are determined. 4) Some suggestions are addressed for effective deployment of Quality 4.0. Conclusion: 1) Definition, key elements, levels, and some suggestions on effective deployment of Quality 4.0 are addressed. 2) Specific contents of Quality 4.0 education and training courses should be provided in the future. 3) Two future research directions are proposed.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.413-416
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• 2006

This paper presents the analytical results on the heat of hydration and induced thermal cracking of the wall elements in LiNAC that is a radioactive shield concrete structure. This wall elements measuring 1.2 m in thickness and 32 m in length tend to exhibit thermal cracking due to heat of hydration and high constraint effects caused by slab element located in the lower part of structure. In this analysis, four different construction stages were considered to find out the most effective concrete casting method in terms of thermal stress. Among the construction methods adopted in this analysis, the method of installation of construction connection measuring 1.2 m at the both side of wall elements was very effective way to control the thermal stress, resulting in increase thermal cracking index of wall elements in LiNAC structure. Finally, the wall elements in LiNAC structure was cast successfully according to the proposed construction method.

• 한국국방경영분석학회지
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• 제31권2호
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• pp.45-59
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• 2005

As more advanced and complicated equipments are introduced, effective operation and maintenance, along with acquisition of the equipments, commands more significance lately. In order to perform effective depot maintenance, the Republic of Korea Army is continually developing the concept, cycle and method for operating the depot maintenance. Not only the high-cost testing and maintenance equipments but the highly developed maintenance technologies are required for the depot maintenance of the latest weapon system. In order to have the depot maintenance capability, this paper provides the standard and procedure for estimating the development cost of the depot maintenance elements to be utilized in the depot maintenance elements development project.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1994년도 봄 학술발표회 논문집
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• pp.65-72
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• 1994

This study presents the application of multi-level substructuring for the effective nonlinear analysis of coupled wall structures. Also, the transition elements with 8 or 12 d. o. f, 5-node plane stress elements and concrete nonlinear model are considered as the basic finite elements of substructuring. In particular, the concept of localized nonlinearity is considered for the probable nonlinear zones of the structure, and the effective bottom-up and top-down process are presented through connectivity trees. The nonlinear analysis based on localized nonlinearity and multi-level substructuring, compared with the complete nonlinear analysis of the structure, gives the greater saving effects in computational efforts and cost.

• 정보관리학회지
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• 제15권2호
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• pp.137-162
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• 1998

본 연구의 목적은 디지털 도서관 환경에서 도서, 비도서자료 및 인터넷자원을 포괄적으로 기술할 수 있는 서지레코드 핵심데이터요소를 제시하는데 있다. 이를 우해 현대 편목규칙의 기반이 되는 AACR2R의 기술사항, 목록의 비용효과를 효율적으로 거둘수 있는 미국국회도서관의 핵심레코드(Core Record), 인터넷자원을 기술하기 위해 제안된 더블린코어(Dublin Core) 메타데이터, KORMARC 등의 데이터요소를 비교분석하였다. 비교결과를 토대로 핵심데이터요소를 필수요소, 적용 가능한 경우에 필수요소, 선택요소로 구분하여 제안하였다.

• Journal of Astronomy and Space Sciences
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• 제38권3호
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• pp.175-183
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• 2021

The dependencies of the chemical element abundances in stellar atmospheres with respect to solar abundances on the second ionization potentials of the same elements were investigated using the published stellar abundance patterns for 1,149 G and K giants in the Local Region of the Galaxy. The correlations between the relative abundances of chemical elements and their second ionization potentials were calculated for groups of stars with effective temperatures between 3,764 and 7,725 K. Correlations were identified for chemical elements with second ionization potentials of 12.5 eV to 20 eV and for elements with second ionization potentials higher than 20 eV. For the first group of elements, the correlation coefficients were positive for stars with effective temperatures lower than 5,300 K and negative for stars with effective temperatures from 5,300 K to 7,725 K. The results of this study and the comparison with earlier results for hotter stars confirm the variations in these correlations with the effective temperature. A possible explanation for the observed effects is the accretion of hydrogen and helium atoms from the interstellar medium.

• Nuclear Engineering and Technology
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• 제45권7호
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• pp.839-846
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• 2013

This paper describes a finite element model of the microstructure of dispersion type nuclear fuels, which can be used to determine the effective thermal conductivity of the fuels during irradiation. The model simulates a representative region of the fuel as a prism shaped unit cell made of brick elements. The elements within the unit cell are assigned material properties of either the fuel or the matrix depending on position, in such a way as to represent randomly distributed fuel particles with a size distribution similar to that of the as manufactured fuel. By applying an appropriate heat flux across the unit cell it is possible to determine the effective thermal conductivity of the unit cell as a function of the volume fraction of the fuel particles. The presence of a fuel/matrix interaction layer is simulated by the addition of a third set of material properties that are assigned to the finite elements that surround each fuel particle. In this way the effective thermal conductivity of the material may also be determined as a function of the volume fraction of the interaction layer. Work is on going to add fission gas bubbles in the fuel as a fourth phase to the model.

• 한국과학교육학회지
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• 제27권6호
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• pp.529-545
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• 2007

Questioning forms an integral part of most strategies for effective teaching when the class consists of difficult content. Science including chemistry is usually content-rich, but difficult to understand without supporting lab experiments, subsidiary visual materials and model kits. Engaging the attention and interest of students in such a subject, therefore, is the key to the success of a daily lesson in the classroom. However, generating meaningful questions requires a certain level of information and metacognitive skills on the part of the teacher. The purpose of this study was to find out the framework of effective teachers' questioning with a large group in chemistry class: how teachers used questioning to engage their students in such a big class, to identify a variety of forms of feedback provided by students and to develop a model of question-inducing strategies. We investigated the teachers' recognition of their questioning and the students' recognition of teachers' questioning by surveying over 82 teachers and 434 students in Korea. The survey findings show that the questionnaire can be categorized into four elements: the theme of the teachers' questions (T), students' inquiries (I), methods of teachers' questioning (M) and encouragement of students (E). These elements can be analyzed and sub-categorized to find out which elements are effective in good questioning, even though the elements are interwoven tetrahedrally.