• Structural Engineering and Mechanics
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• 제6권6호
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• pp.711-725
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• 1998

Mixed finite element formulations for incompressible materials show pressure oscillations or pressure modes in four-node quadrilateral elements. The criterion for the stability in the pressure solution is the so-called Babu$\check{s}$ka-Brezzi stability condition, and the four-node elements based on mixed variational principles do not appear to satisfy this condition. In this study, a pressure continuity residual based on the pressure discontinuity at element edges proposed by Hughes and Franca is used to study the stabilization of pressure solutions in bilinear displacement-constant pressure four-node quadrilateral elements. Also, a solid mechanics problem is presented by which the stability of mixed elements can be studied. It is shown that the pressure solutions, although stable, are shown to exhibit sensitivity to the stabilization parameters.

• 한국멀티미디어학회논문지
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• 제24권6호
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• pp.815-824
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• 2021

Based on the theory of space perception, this paper concludes that the mixed reality application under the theory of space perception has a three-level definition of visual hierarchy and then analyzes the component elements of interface design and the classification mode of interface windows. Next, carry out case practice research through this theoretical definition, and finally conduct the survey and analysis of questionnaire data, verifying that the mixed reality interface design based on spatial perception theory meets the user experience elements of Usability, Availability, and Attraction. The conclusion is that the constituent elements of interface design and the window classification mode can provide specific and practical design specifications for mixed reality interface design, reduce the interaction cost of completing tasks, reduce users' cognitive load, and make it easier for users to receive interface information

• 한국응용과학기술학회지
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• 제27권2호
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• pp.123-128
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• 2010

The continuous transesterification of mixed fat was done on the plug flow reactor packed with the static mixers. The transesterification using 0.5 wt% KOH, 0.8 wt% TMAH and mixed catalyst[40 v/v% KOH(0.5 wt%)+60 v/v% TMAH(0.8 wt%)] was conducted with the changes of molar ratios, weight percentage of beef, flow rates and number of static mixer's elements at $65^{\circ}C$. The overall conversion of mixed fat at 1:8 molar ratio, 50 wt% of beef and 24 of static mixer's elements increased until 0.7mL/min of flow rate. The overall conversion of mixed fat showed 96% at those conditions. So, the optimum operating conditions on tublar reactor were 1:8 molar ratio, 50 wt% of beef, 0.7 mL/min of flow rate and 24 of static mixer' s elements.

• 한국실내디자인학회:학술대회논문집
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• 한국실내디자인학회 2008년도 춘계학술발표대회 논문집
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• pp.264-269
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• 2008

The usage of this paper is to analyze the characteristics of architectural publicity expressed in the spaces of mixed-use facilities in Japan. The research method was as follows: 1) preparatory study and literature research review to extract the elements of architectural publicity 2) A survey, to check architectural publicity elements 3) Based on the elements of architectural publicity, each mixed-use facility was evaluated; 4) Spaces of the facilities were classified based on Kevin Lynch's. The Image of the City element. The results show that the mixed-use facilities Include aspects of "space use aspect" and "space structural aspect". Second, the entrance areas of the facilities were characterized by strengthened spatial legibility and sense of area. Third, the paths were characterized by visual openness, accessibility, inter-relatedness, and space amenity, Fourth, the spaces that perform certain functions within the facilities were characterized by improved space amenity, convenience, and social interchange. Fifth, the nodes were characterized by increased social interchange and spatial transferability. Sixth, the landmark spaces were characterized by improved spatial legibility.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1993년도 가을 학술발표회논문집
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• pp.8-15
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• 1993

The transition membrane elements with drilling freedom have been developed. The functionals for the linear problem, in which the drilling rotations are introduced as independent variables, have been presented by Hughes & Bressi. And 4-node membrane elements with drilling degrees of freedom were developed by Ibrahimbegovic. The transition elements can be efficiently used in modelling the in-plane structures, in particular, where the stress concentration exists. A modified Gaussian quadrature adopted to evaluate the stiffness matrices of these transition elements which have slope discontinuity of displacement within the elements. Detailed numerical studies show the excellent performance of the transition elements.

• 조명전기설비학회논문지
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• 제26권4호
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• pp.41-47
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• 2012

This paper deals with the electrical characteristics related to power loss, equivalent resistance, and leakage currents flowing through new and deteriorated zinc oxide(ZnO) arrester elements subjected to the mixed DC and 60[Hz] AC voltages. The test specimens were deteriorated by 8/20[${\mu}s$] impulse current of 2.5[kA]. The leakage current-applied voltage($I-V$) characteristic curves of ZnO surge arrester elements were measured as a parameter of the ratio of the peak of 60[Hz] AC voltage to the peak of total voltage. As a consequence of test results, in case of the same applied voltage, the leakage currents flowing through the deteriorated ZnO arrester elements were higher than those flowing through the new ZnO surge arrester elements. The cross-over phenomenon in $I-V$ curves of ZnO surge arrester elements measured as a parameter of the mixed ratio of DC and AC voltages was observed at the low current domain. The effect of DC voltage on the leakage current flowing through ZnO surge arrester elements is pronounced at the same magnitude of test voltages. In addition, the larger the applied number of 8/20[${\mu}s$] impulse current of 2.5[kA] is, the greater the power loss is, in particular, the more severe the power loss increases at higher applied voltages.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.1179-1186
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• 2022

Building Information Modeling (BIM) is widely used to efficiently share, utilize and manage information generated in every phase of a construction project. Recently, mixed reality (MR) technologies have been introduced to more effectively utilize BIM elements. This study deals with the haptic interactions between humans and BIM elements in MR to improve BIM usability. As the first step in interacting with virtual objects in mixed reality, we challenged moving a virtual object to the desired location using finger-pointing. This paper presents the procedure of developing a haptic interface system where users can interact with a BIM object to move it to the desired location in MR. The interface system consists of an MR-based head-mounted display (HMD) and a mobile application developed using Unity 3D. This study defined two segments to compute the scale factor and rotation angle of the virtual object to be moved. As a result of testing a cuboid, the user can successfully move it to the desired location. The developed MR-based haptic interface can be used for aligning BIM elements overlaid in the real world at the construction site.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1995년도 가을 학술발표회 논문집
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• pp.153-160
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• 1995

Mixed finite element formulations for incompressible materials show pressure oscillations or pressure modes in four-node quadrilateral elements. The criterion for the stability in the pressure solution is the so-called Babufka-Brezzi stability condition, and the four-node elements based on mixed variational principles do not appear to satisfy this condition. In this study, a pressure continuity residual based on the pressure discontinuity at element edges is used to study the stabilization of pressure solutions in bilinear displacement-constant pressure four-node quadrilateral elements. It is shown that the pressure solutions, although stable, exhibit sensitivity to the stabilization parameters.

• 전산구조공학
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• 제3권4호
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• pp.91-104
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• 1990

사각형 판 유한요소의 정적 성능을 여러 가지 문제에 대한 수치 실험을 통해 비교 분석하였다. Kirchhoff이론과 Mindlin이론에 근거한 변위요소, 평형요소, Mixed 또는 Hybrid요소들을 대상으로 문헌조사를 통해 우수요소를 선정하였으며 사각형 판 문제, 마름모형 판 문제, 원형 판 문제, 외팔보형 판 문제를 다양한 격자, 경계조건에 대해 풀어 해를 비교하였다. Kirchhoff요소에서는 12자유도요소로 Armanios의 요소, 24 자유도 요소로 Watkins요소의 거동이 우수하였으나 전반적으로 Mindlin요소에 비해 거동이 떨어진다. Mindlin요소 중에서는 Hinton의 요소가 효율성, 수렴성, 신뢰성의 면에서 가장 우수하나 마름모형 판 문제나 뒤틀린 격자 문제등에서는 거동이 좋지 않으므로 계속 연구할 필요가 있다.

• 동력기계공학회지
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• 제4권1호
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• pp.68-73
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• 2000

A mixed degree finite element solutions using hierarchical elements are investigated for convergences on a 2-D simple cases. Elements are generated block by block and each block is assigned an arbitrary solution degree. The numerical study showed that a well constructed blocks can increase the convergence and accuracy of finite element solutions. Also, it has been found that for higher order elements, the convergence trends can be deteriorated for smaller mesh sizes. A procedure for a variable fixed boundary condition has been included.