• Journal of Korean Ophthalmic Optics Society
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• v.4 no.2
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• pp.147-154
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• 1999

This study was performed to survey the exchange of frames on 83 persons. We investigated frame size, frame type, binocular prism effect etc. 80.4% among motives of frame-exchanges was a damage or corrosion. The type of frames was round-like 62.4% and 37.6% square-like. The size of frames was $49{\Box}18$ and vertical length 33mm on old-frames, $47{\Box}17$ and 31mm on new-frames. The scope of axis variation was average +3.20~3.80. According to estimation by the rule of RAL-RG 915, the inappropriate horizontal prism effect of new spectacles was 42.2%, more than 38.5% on old spectacles. The inappropriate vertical prism effect was 24.1% on old, 33.7% on new spectacles.

• Computers and Concrete
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• v.27 no.4
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• pp.343-353
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• 2021

In this study, in order to improve the seismic performance of existing reinforced concrete (RC) framed structures, various external attachment of corner steel frame configurations was considered as a user-friendly retrofitting method. The external steel frame is designed to contribute to the lateral stiffness and load carrying capacity of the existing RC structure. A six-story building was taken into account. Four different external corner steel frame configurations were suggested in order to strengthen the building. The 3D models of the building with suggested retrofitting steel frames were developed within ABAQUS environment using solid finite elements and analyzed under horizontal loadings nonlinearly. Horizontal top displacement vs loading curves were obtained to determine the overall performance of the building. Contributions of steel and RC frames to the carried loads were computed individually. Load/capacity ratios for the ground floor columns were presented. In the study, 3D rendered images of the building with the suggested retrofits are created to better visualize the real effect of the retrofit on the final appearance of the façade of the building. The analysis results have shown that the proposed external steel frame retrofit configurations increased the lateral load carrying capacity and lateral stiffness and can be used to improve the seismic performance of RC framed buildings.

• Steel and Composite Structures
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• v.48 no.3
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• pp.321-333
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• 2023

This paper proposes a comprehensive investigation on lateral stiffness of corner-supported steel modular frame using splice connection. A full-scale modular frame with two stacked steel modules under lateral load is tested. Ductile pattern in the transfer of lateral load is found in the final failure mode. Two types of lateral stiffness, including tangent stiffness and secant stiffness, are defined from the load-displacement due to the observed nonlinearity. The difference between these two types of stiffness is found around 20%. The comparisons between the experimental lateral stiffness and the predictions of classical methods are also conducted. The D-value method using hypothesis of independent case is a conservative option for predicting lateral stiffness, which is more recommended than method of contraflexural bending moment. Analyses on two classical short-rod models, including fix-rod model and pin-rod model, are further conducted. Results indicate that fix-rod model is more recommended than pin-rod model to simplify splice connection for simulation on lateral stiffness of modular frame in elastic design stage.

• Journal of Computational Design and Engineering
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• v.2 no.1
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• pp.67-72
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• 2015

Recently, along with the improvements of geometry modeling methods using sketch-based interface, there have been a lot of developments in research about generating surface model from 3D curves. However, surfacing a 3D curve network remains an ambiguous problem due to the lack of geometric information. In this paper, we propose a new algorithm for estimating the normal vectors of the 3D curves which accord closely with user intent. Bending energy is defined by utilizing RMF(Rotation-Minimizing Frame) of 3D curve, and we estimated this minimal energy frame as the one that accords design intent. The proposed algorithm is demonstrated with surface model creation of various curve networks. The algorithm of estimating geometric information in 3D curves which is proposed in this paper can be utilized to extract new information in the sketch-based modeling process. Also, a new framework of 3D modeling can be expected through the fusion between curve network and surface creating algorithm.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.11
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• pp.621-628
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• 2003

This paper addresses a method of enabling objects in an image to have apparent 3D motion. Many researchers have solved this issue by reconstructing 3D model from several images using image-based modeling techniques, or building a cube-modeled scene from camera calibration using vanishing points. This paper, however, presents the possibility of image-based motion without exact 3D information of scene geometry and camera calibration. The proposed system considers the image plane as a projective plane with respect to a view point and models a 2D frame of a projected 3D object using only lines and points. And a modeled frame refers to its vanishing points as local coordinates when it is transformed.

• Journal of Broadcast Engineering
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• v.18 no.5
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• pp.680-690
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• 2013

In this paper, we propose a real-time temporal synchronization and compensation algorithm in stereoscopic video. Many temporal asynchronies are caused in the video editing stage and due to different transmission delays. These temporal asynchronies can degrade the perceived 3D quality. The goal of temporal alignment is to detect and to measure the temporal asynchrony and recover synchronization of the two video streams. In order to recover synchronization of the two video streams, we developed a method to detect asynchronies between the left and the right video streams based on a novel spatiogram information, which is a richer representation, capturing not only the values of the pixels but their spatial relationships as well. The proposed novel spatiogram additionally includes the changes of the spatial color distribution. Furthermore, we propose a block-based method for detection of the pair frame instead of one frame-based method. Various 3D experiments demonstrate the effectiveness of the proposed method.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.113-120
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• 2001

A frame slab method has been proved as a possible and profitable construction solution for the urban tunnels with very shallow overburden and the excavation from the surface Is strictly limited. Since this method allows only a small amount of construction activities in the ground surface, the disturbances to the public and the surface traffic can be drastically reduced compared with the ordinary cut-and-cover method. The construction sequences of the method and the some of critical cautions needed are described in detail. Also a comprehensive numerical analysis including 2-D and 3-D analysis have been performed to verify the stability of the ground during the construction. It is revealed from this study that the frame slab method can be a quite successful solution for the shallow overburden tunnelling in urban area.

• International Journal of Concrete Structures and Materials
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• v.10 no.3
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• pp.307-323
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• 2016

The nonlinear behaviors of recycled aggregate concrete (RAC) frame structure are investigated by numerical simulation method with 3-D finite fiber elements. The dynamic characteristics and the seismic performance of the RAC frame structure are analyzed and validated with the shaking table test results. Specifically, the natural frequency and the typical responses (e.g., storey deformation, capacity curve, etc.) from Model 1 (exclusion of strain rate effect) and Model 2 (inclusion of strain rate effect) are analyzed and compared. It is revealed that Model 2 is more likely to provide a better match between the numerical simulation and the shaking table test as key attributes of seismic behaviors of the frame structure are captured by this model. For the purpose to examine how seismic behaviors of the RAC frame structure vary under different strain rates in a real seismic situation, a numerical simulation is performed by varying the strain rate. The storey displacement response and the base shear for the RAC frame structure under different strain rates are investigated and analyzed. It is implied that the structural behavior of the RAC frame structure is significantly influenced by the strain rate effect. On one hand, the storey displacements vary slightly in the trend of decreasing with the increasing strain rate. On the other hand, the base shear of the RAC frame structure under dynamic loading conditions increases with gradually increasing amplitude of the strain rate.

• Journal of Korea Multimedia Society
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• v.8 no.1
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• pp.9-18
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• 2005

This paper presents the method of calculating the quantization level of the intra-frame in MPEG-4 video encoder. The intra-frame is an essential part in that the quality of the whole GOP is affected by the quality of this frame since the intra-frame, which works as a reference frame within GOP, continuously propagates through other frames. This work proposes how to use bits assigned for gaining the quantization level of the intra-frame, complexity of input images, and GOP structures. The result shows that while existing approaches have the decline in efficiency by using fixed values or show different qualifies depending on the characteristics of the images, the current approach shows the steady results in various images. Comparing with Q2 algorithm obtained in MPEG-4 VM, the approach suggested in this paper gains the benefit of maximum 3.49dB with some variations depending on the characteristics of the images.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.6
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• pp.62-69
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• 2015

In this paper, a new frame rate up conversion (FRUC) algorithm using adaptive motion estimation (AME-FRUC) is proposed. The proposed algorithm performs extended bilateral motion estimation (EBME) conducts motion estimation (ME) processes on the static region, and extract region of interest with the motion vector (MV). In the region of interest block, the proposed AME-FRUC uses the texture block partitioning scheme and the unilateral motion estimation for improving ME accuracy. Finally, motion compensated frame interpolation (MCFI) are adopted to interpolate the intermediate frame in which MCFI is employed adaptively based on ME scheme. Experimental results show that the proposed algorithm improves the PSNR up to 3dB, the SSIM up to 0.07 and 68% lower SAD calculations compared to the EBME and the conventional FRUC algorithms.