• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.443-448
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• 2002

The cross sections of structural walls have various shapes such as T, L, and H-shaped. The L-shaped walls frequently appear in the comer of the structural plans. There are a little researches on the structural performance of L-shaped walls subjected to hi-directional loads. L-shaped wall subjected to hi-directional loads might be failed due to high compressive stress in the corner of the wall. L-shaped wall subjected to bi-directional(45$^{\circ}$ direction) loads was failed by the compressive failure more possible than that of one-directional(0$^{\circ}$ direction) loads. Therefore, in this paper, Two L-shaped wall specimens are chosen and presented. One is LCU specimen subjected to the bi-directional loads, the other is LCX specimen subjected to the one-directional loads. Also, the experimental results compared with the analytical results from nonlinear FEM analysis.

• IEMEK Journal of Embedded Systems and Applications
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• v.16 no.6
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• pp.285-292
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• 2021

Autonomous vehicles are divided into an upper controller that calculates control value through cognitive judgment and a lower controller that appropriately transmits its control value to an actuator. Here, the longitudinal control in a lower controller has a problem as the road slopes due to the property of the Acceleration sensor to output the acceleration as the slope of the device. Therefore, in this paper, a sigmoid function is proposed to determine the slope to compensate for this problem. Through the experiment, Checked performance by comparing the existing table model with the proposed model.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.49 no.3
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• pp.40-50
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• 2012

In this paper we propose the fast CU (Coding Unit) mode decision method. To reduce computational complexity and save encoding time of HEVC, we divided CU, PU (Prediction Unit) and TU (Transform Unit) decision process into two stages. In the first stage, because $2N{\times}2N$ PU mode is mostly selected among $2N{\times}2N$, $N{\times}2N$, $2N{\times}N$, $N{\times}N$ PU modes, proposed algorithm uses only $2N{\times}2N$ PU mode deciding depth of each CU in the LCU (Largest CU). And then, proposed method decides exact PU and TU modes at the depth level which is decided in the first stage. In addition, early skip decision rule is applied to the proposed method to obtain more efficient computational complexity reduction. The proposed method reduces computational complexity of the HEVC encoder by simplifying a CU depth decision method. We could obtain about 50% computational complexity reduction in comparison with HM 3.3 HEVC reference software while bitrate compressed by the proposed algorithm increases only 2%.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.5
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• pp.272-279
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• 2002

A field experiment was conducted to investigate the effect of N-use efficiency and rice yield by rapeseed cake(organic fertilizer) application at panicle initiation stage in machine transplating cultivation from 1999 to 2000. The rice yield increased by 4% in "50% rapeseed cake application", by 2% in "30% rapeseed cake application" at panicle initiation stage, respectively. Amount of fertilizer N uptake was high according to increasing amount of rapeseed cake application at panicle initiation stage compared with conventional treatment, but percentage recovery of fertilizer N was higher in 30% rapeseed cake application than in 50% rapeseed cake application at panicle initiation stage. Thus, this result was thought that there was more adventageous in 30% rapeseed cake application than 50% rapeseed cake application at panicle initiation stage in the fertilizer reduction or N-use efficiency respects in rice paddy.

• Restorative Dentistry and Endodontics
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• v.29 no.6
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• pp.504-514
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• 2004

This study compared the dentin shear bond strengths of currently used dentin bonding agents that were irradiated with an LED (Elipar FreeLight, 3M-ESPE) and a halogen light (VIP, BISCO). The optical characteristics of two light curing units were evaluated. Extracted human third molars were prepared to expose the occlusal dentin and the bonding procedures were performed under the irradiation with each light curing unit. The dentin bonding agents used in this study were Scotchbond Multipurpose (3M ESPE), Single Bond (3M ESPE), One-Step (Bisco), Clearfil SE bond (Kuraray), and Adper Prompt (3M ESPE), The shear test was performed by employing the design of a chisel-on-iris supported with a Teflon wall. The fractured dentin surface was observed with SEM to determine the failure mode. The spectral appearance of the LED light curing unit was different from that of the halogen light curing unit in terms of maximum peak and distribution. The LED LCU (maximum peak in 465 nm) shows a narrower spectral distribution than the halogen LCU (maximum peak in 487 nm). With the exception of the Clearfil SE bond (P < 0.05), each 4 dentin bonding agents showed no significant difference between the halogen light-cured group and the LED light-cured group in the mean shear bond strength (P > 0.05). The results can be explained by the strong correlation between the absorption spectrum of camphoroquinone and the narrow emission spectrum of LED.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.295-298
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• 2014

In this paper, an efficient design of HEVC Adaptive Loop Filter(ALF) for filter coefficients estimation is proposed. The ALF performs Cholesky decomposition of $10{\times}10$ matrix iteratively to estimate filter coefficients. The Cholesky decomposition of the ALF consists of root and division operation which is difficult to implement in a hardware design because it needs to many computation rate and processing time due to floating-point unit operation of large values of the Maximum 30bit in a LCU($64{\times}64$). The proposed hardware architecture is implemented by designing a root operation based on Cholesky decomposition by using multiplexer, subtracter and comparator. In addition, The proposed hardware architecture of efficient and low computation rate is implemented by designing a pipeline architecture using characteristic operation steps of Cholesky decomposition. An implemented hardware is designed using Xilinx ISE 14.3 Vertex-6 XC6VCX240T FPGA device and can support a frame rate of 40 4K Ultra HD($4096{\times}2160$) frames per second at maximum operation frequency 150MHz.

• IEIE Transactions on Smart Processing and Computing
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• v.1 no.3
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• pp.171-181
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• 2012

In the new video coding standard, called high efficiency video coding (HEVC), the coding unit (CU) is adopted as a basic unit of a coded block structure. Therefore, the rate control (RC) methods of H.264/AVC, whose basic unit is a macroblock, cannot be applied directly to HEVC. This paper proposes the largest CU (LCU) level RC method for hierarchical video coding in a HEVC. In the proposed method, the effective bit allocation is performed first based on the hierarchical structure, and the quantization parameters (QP) are then determined using the Cauchy density based rate-quantization (RQ) model. A novel method based on the linear rate model is introduced to estimate the parameters of the Cauchy density based RQ model precisely. The experimental results show that the proposed RC method not only controls the bitrate accurately, but also generates a constant number of bits per second with less degradation of the decoded picture quality than with the fixed QP coding and latest RC method for HEVC.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1910-1913
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• 2005

As the various manufacturing technology of optical glass is developed, the aspherical lenses are applied to many fields. However, It is still very difficult to manufacture glass lens because of the high cost and the short life of core. In recent years, the demands of the aspherical glass lenses increase since it is difficult to obtain the desirable performance in the plastic lens. In the glass mold lens, it has merits of high productivity and reproductivity since lens is manufactured by the only forming with high precision mold. The fabricating conditions for glass mold lens are glass surface that does not cause fusion, viscosity of 108-1013 poise for the $0.2{\mu}m$ accuracy, and viscoelasticity for the roughness less than 100 angstrom. In this paper, ultra-precision grinding characteristics of tungsten carbide for forming the aspherical glass lens core were studied and the result of it is applied to manufacture the tungsten carbide-base cores of the glass lens used to the laser scanning unit and the camera phone.

• Safety and Health at Work
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• v.12 no.4
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• pp.505-510
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• 2021

Background: Factors related to root causes can cause commonly occurring accidents such as falls, slips, and jammed injuries. An important means of reducing the frequency of occupational accidents in small- to medium-sized enterprises (SMSEs) of South Korea is to perform intensity analysis of the root cause factors for accident prevention in the cause and effect model like decision models, epidemiological models, system models, human factors models, LCU (life change unit) models, and the domino theory. Especially intensity analysis in a robot system and smart technology as Industry 4.0 is very important in order to minimize the occupational accidents and fatal accident because of the complexity of accident factors. Methods: We have developed the modern cause and effect model that includes factors of root cause through statistical testing to minimize commonly occurring accidents and fatal accidents in SMSEs of South Korea and systematically proposed educational policies for accident prevention. Results: As a result, the consciousness factors among factors of root cause such as unconsciousness, disregard, ignorance, recklessness, and misjudgment had strong relationships with occupational accidents in South Korean SMSEs. Conclusion: We conclude that the educational policies necessary for minimizing these consciousness factors include continuous training procedures followed by periodic hands-on experience, along with perceptual and cognitive education related to occupational health and safety.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.251-254
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• 2020

매년 1인 가구를 대상으로 한 범죄가 증가하고 있다. 이에 따라 지문인식, 스마트키와 같은 도어록 제품들이 출시되었지만 오히려 범죄에 악용되는 사례들이 발생하였다. 본 논문에서는 얼굴인식장치(face identifier, FI)를 통해 객체를 인식하고, 원격 도어록 관리자(remote door lock manager, RDM)를 통해 잠금제어부(locking control unit, LCU)를 관리하는 긴급 상황 인식 스마트 도어록을 제안한다. 사용자의 얼굴을 얼마나 빠르고 정확하게 인식하는지 속도와 신뢰도에 대한 테스트를 진행하였고, 긴급 상황 시 사용자가 안전하게 집으로 들어갈 수 있음을 확인하였다. 본 제품을 통해 주거 침입, 스토킹 등 1인 가구 대상 범죄율과 도어록 악용 범죄율이 낮아질 것으로 사료된다.