• The tire
• /
• s.19
• /
• pp.23-28
• /
• 1969

• Journal of the Korean School Mathematics Society
• /
• v.21 no.2
• /
• pp.183-206
• /
• 2018

It arises that teachers' professional competence should be considered not only with a cognitive perspective but also with a situative perspective. In this study, we considered mathematics teacher noticing as situational professional competencies of a mathematics teacher, and explored how mathematics teachers noticing on children's development of reasoning about variability in a video club has changed with the situative perspective. Findings illustrate that the 'interpreting' component among the three components of noticing-attending, interpreting, and deciding how to respond-was critically decisive for the change of the participant teachers' noticing. We also discussed how the video club intervention(the framework of children's development of reasoning about variability) can support the development of teacher noticing as a professional competence. This study has implications on the design of a video club to improve mathematics teacher noticing.

• Journal of Korean Society of Steel Construction
• /
• v.19 no.1
• /
• pp.129-137
• /
• 2007

In this study, the elastic out-of-plane buckling load and the effective length factor of X-bracing systems were studied. Points of the intersection of diagonals were modeled as a rigid connection or a pinned connection depending on the connection method of diagonals. The boundary condition of the intersection influences the buckling load of X-bracing systems. For each boundary condition of the intersection, effective out-of-plane length factors of X-bracing systems were derived as a function of the length ratio of tension and compression diagonals $L_P$/$L_T$, the applied force ratio of tension and compression diagonals T/P, and the Euler buckling load ratio of tension and compression diagonals $P_{ET}$/$P_{EP}$. The proposed effective out-of-plane length factors of X-bracing systems were compared with the results of previous researchers and those of the finite element analysis and their properties were verified. Finally, the effects of the boundary condition of the intersection on the out-of-plane buckling load of X-bracing systems were investigated.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.4
• /
• pp.400-413
• /
• 2016

The horizontal shear capacity when the flange of a steel girder is replaced with 80 MPa concrete is important for its structural safety. In this study, 6 specimens with different interface conditions were designed and fabricated based on the Limit State Design Code on Korean Highway Bridges and static tests were performed to measure the horizontal shear capacity. Not only the resistance factors of the stud shear connector, concrete and reinforcement, but also the surface conditions of the casing concrete and spacing of the horizontal shear reinforcements were used as the experimental variables. The experiments showed that the interfaces between the steel girder and the concrete flange have stronger joint performance than those between the concrete flange and deck slab. To ensure the composite action in the plastic zone, the conservative horizontal shear reinforcement is more important than the roughness in the concrete face.

• Journal of Broadcast Engineering
• /
• v.15 no.4
• /
• pp.591-599
• /
• 2010

In this paper, we propose a disparity-adaptive filtering method to reduce view-aliasing and inter-perspective aliasing on auto-multiscopic 3D display. View aliasing by the subsampled multi-view images could happen if the resolution of an auto-multiscopic monitor is lower than that of the original multi-view images. Furthermore, multi-view images on auto-multiscopic monitor usually cause eye strain and fatigue because of inter-perspective aliasing by discontinuity that exists between viewpoints. The greater disparity value becomes, the stronger these types of aliasing could be. Thus, we design a lowpass filter whose cut-off frequency is determined adaptively to the number of intermediate reconstructed views and their disparity's strength. Though experimental results, we show that the proposed filtering algorithm could reduce the aliasing effect very efficiently by using DSCQS (double stimulus continuous quality scale method).

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.29 no.4
• /
• pp.347-354
• /
• 2016

Because typical gas turbine systems have frequent startup and shutdown operations, it is likely to cause cracks at the gas turbine casing and gas leakages at casing flanges due to thermal fatigue and embrittlement. Therefore, the evaluation of structural integrity and gas leakage at the gas turbine casings must be performed. In this paper, we have evaluated the structural integrity of the turbine casing and bolts under a normal operation in accordance with ASME B&PVC and evaluated the leakage at casing flanges by examination of contact pressure calculated using the finite element analysis. Finally, we propose a design flow including finite element modeling, the interpretation and evaluation methods for gas turbine casings. This may be utilized in the design and development of gas turbine casings.

• Communications of Mathematical Education
• /
• v.35 no.4
• /
• pp.377-411
• /
• 2021

This study aims to explore central and peripheral beliefs of mathematics teachers in the context of teaching and learning. For this purpose, this study analyzed teacher noticing of 8 mathematics teachers who are in-service in terms of mathematical beliefs using video-clips of math lessons. When the teachers in the video-clips seemed to have a teaching and learning problem, teachers who adopt noticing critized the classroom situation by reflecting his or her own mathematical beliefs and suggested alternatives. In addition, through noticing analysis, teachers' mathematical beliefs reflected in specific topics such as student participation in teaching and learning were compared to reveal their individual central and peripheral beliefs. Through these research results, this study proposed a model that extracts the central and peripheral beliefs of math teachers from the constraints of the teaching and learning context using noticing analysis. Additionally, it was possible to observe the teacher decision-making and expertise of mathematics teachers.

• Education of Primary School Mathematics
• /
• v.27 no.1
• /
• pp.1-18
• /
• 2024

Teachers' ability to notice is a crucial indicator of their instructional expertise. Despite the significance of this ability, research in mathematics teacher education has predominantly focused on the noticing of preservice teachers, with limited exploration into the noticing abilities of experienced in-service teachers. This study addresses this gap by examining the noticing characteristics of in-service elementary teachers actively developing their competency in elementary mathematics education. For this purpose, 23 elementary school teachers were asked to complete an analysis sheet while viewing the mathematics lesson video depicting on the concept of (fraction)÷(natural number), allowing us to scrutinize their attending, interpreting, and responding skills in detail. The study's results revealed that teachers demonstrated a tendency to attend mathematically significant aspects related to the teaching of fraction division. They interpreted the observed phenomena through the lens of fraction division's instructional principles, proposing specific pedagogical alternatives. These findings offer valuable insights for mathematics teacher education research.

• The Journal of the Korea Contents Association
• /
• v.8 no.12
• /
• pp.141-150
• /
• 2008

The purpose of this study is to find the way of enhancing readability with Anti-Aliasing in digital media environment. Subjects of this paper were established analyzing Anti-Aliasing & Multiple Anti-Aliasing. First, this study is to find a actual condition of using Anti-Aliasing in digital media environment. Then Gathered the information of Multiple Anti-Aliasing samples from internat. I made enhancing readablity result with that information and tested this result for finding the best result for readability. This study will present the guid line for the person who is working as a designer in field to find the best result for readability with Multiple Anti-Aliasing. Also, will show us a readablity's possibility of using Multiple Anti-Aliasing for next verson of graphic software.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.17 no.4
• /
• pp.981-988
• /
• 2013

In this paper, we propose a method to generate defocusing images at the focusing plane using the 3D spatial information of object through pickup process of integral imaging technique. In the proposed method, the focusing and defocusing images are generated by the convolution operation between elemental images and ${\delta}$ function array. We observed the image difference by defocusing degree according to the distance of focusing plane. To show the feasibility of the proposed method, some preliminary experiments are carried out and the results are presented.