• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.1
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• pp.23-34
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• 1998

A dynamic fluid-structure-soil interaction analysis method is developed to investigate the effects of translational and/or rocking motions on the seismic response of flexible rectangular liquid storage tanks founded on the deformable ground. The governing equation for the dynamics of 3-D rectangular tanks subjected to the translational and/or rocking motion is abtained by applying Rayleigh-Ritz method. The dynamic stiffness matrices of a rigid rectangular foundation resting on the surface of a stratum overlaid bedrock are calculated by hyperelement method. The seismic responses of 3-D flexible tank model founded on the deformable ground is calculated by combining the governing equation for the fluid-tank system with the dynamic stiffness matrix of th rigid surface foundation.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.1370-1373
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• 2013

영상에서 사람의 얼굴 영상을 추출하여 성별 및 연령대를 자동으로 분석하는 시스템은 광고판 등을 이용한 마케팅, 보안, 통계 분야 등 여러 가지 적용이 가능하다. 이러한 시스템의 개발을 위해서는 얼굴 인식 알고리즘과 특성 분류 알고리즘이 요구된다. 그러나 기존 알고리즘의 경우 문제점이 존재한다. 얼굴 인식 알고리즘으로 가장 많이 사용되는 HAAR 특징은 오탐률이 높으며, 특성 분류 알고리즘으로 사용하는 Fisherface 기법의 경우 분류 Class가 3가지 이상시 분류 성공률이 현저히 떨어지는 문제점이 있다. 본 논문에서는 이 두 알고리즘의 문제점을 개선한 새로운 알고리즘을 제안한다. 얼굴 인식을 위해 기존 HAAR 특징과 LBP 특징을 결합하여 오탐률을 크게 감소시켰다. 또한 특성 분류를 위하여 3 Class 이상의 분류를 대체할 방법으로 2 Class-multi-level 반복 분류방식을 사용하였다. 대량의 데이터에 대한 실험을 통하여 제안한 방법이 기존 방법들보다 성능이 향상되었음을 보인다.

• Composites Research
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• v.22 no.5
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• pp.30-36
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• 2009

The failure strengths and modes in carbon fiber reinforced polymeric composites, with two serial bolt-fastened composite joints, were investigated to evaluate the typical joint configurations of composite components. The parametric studies were performed experimentally at room temperature dry and elevated temperature wet, $82.2^{\circ}C$ on several different laminate configurations. Based on the experimental data presented, two basic load-displacements curves are observed. Each failure mode has the characteristic curve. It is showed that the bearing failure mode occurs in elevated temperature wet condition. It is analysed that the strength of bearing failure mode is not highly depending on the effective modulus of specimen. The failure strength at elevated temperature wet is decreased by the cause of interfacial deterioration between fiber and matrix with moisture absorption.

• Korean Journal of Social Issues
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• v.18 no.1
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• pp.33-56
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• 2017

이 연구에서는 서구와 한국에서의 신자유주의화에 대한 기존의 연구성과들에 기반하여 한국적 신자유주의의 특징을 규명하고, 이명박 정부 이후의 구체적인 정책 변화를 검토하여 국가의 정책이 사회적 불평등에 어떠한 영향을 미쳐 왔는지를 확인하고자 한다. 전체적으로 이 연구가 던지는 질문은 다음과 같다: "국민경제는 계속 성장하고 있다는데, 나는 왜 먹고살기가 더욱 어려워지는가?"라는 질문에 대해 어떻게 대답할 것인가? 이 연구는 이론적인 차원에서 이에 대한 대답은 '신자유주의적 금융화의 진전'이라는 현상과 관련하여 설명되어야 한다는 관점에서 출발한다. 이러한 방식의 설명을 위해 이 글에서 파악하고자 하는 내용은 다음과 같다: 한국에서 신자유주의화 또는 금융화가 전개되는 독특한 양식은 무엇인가? '보수정부' 9년간의 사회경제정책은 이전 시기에 비해 어떤 특징을 나타내는가? 그리고, 이 시기에 한국사회의 사회적 불평등의 정도는 실제로 어떻게 변화하였는가? 글은 신자유주의에 대한 새로운 이론이나 금융화 및 불평등에 대한 새로운 경험적 자료를 제시하기 보다는, 금융화와 불평등에 대한 기존의 논의들을 살펴보고 한국의 신자유주의 및 금융화가 진화해 온 방식과 그 지형도를 그리는 것을 목표로 한다. 그리고 이러한 작업을 통해 향후 기대되는 연구의 방향을 제시하고자 한다. 연구는 첫째로 지난 9년간 전개된 금융정책은 금융이 산업을 지배한다기보다는 오히려 정 반대의 과정으로 진행되도록 했다는 점을 제시할 것이다. 또한, '일하는 복지'라는 사회복지정책 의제와 금융장치의 결합을 통해 개개인의 금융활동에 대한 의존을 심화시켰다는 점을 제시할 것이다. 이러한 정책적 변화들은 곧 물질적인 평등뿐만 아니라, '사회적 권리'로서의 평등을 악화시켰다고 관찰된다.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2022.10a
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• pp.299-300
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• 2022

구조물의 내진보강방법 중에서 가장 널리 이용되는 방법인 강재 이력형 감쇠장치는 수평하중에 대한 응력-변위 곡선을 이용하여 지진 에너지를 소산시키는 방법인데, 이 경우 편심하중 등에 의해서 부재가 면 외 방향으로 거동하여 응력-변위곡선이 불규칙하여 그 결과의 신뢰성이 떨어지는 경우가 있다. 이러한 형상을 방지하기 위해서는 별도의 채널(Channel)을 시공하는 불편함을 감수해야 하며, 또한 수평력이 반복적으로 작용할 때 그 효과를 장담할 수 없는 문제점이 있다. 본 연구에서는 강재 스트립과 스프링을 결합한 댐퍼를 고안하여 스프링은 탄성변형을, 강재 스트립은 소성변형을 받게 하는 혼합형 댐퍼를 개발하고자한다. 여기서, 스프링은 복원력으로 작용하여 반복하중에 대한 저항성을 키우고 강재 스트립의 하중변위 곡선을 규칙적으로 하는 역할을 수행하게 되며 에너지 소산량을 계산할 때 편리함과 정확도를 높이고자 한다. 강재 스트립의 폭과 길이는 일정하지만 두께를 변화시켜서 5종류를 선택하였으며, 댐퍼 1개당 3개의 스트립을 정삼각형 형태로 배치하고 그 중심에 상당한 강성을 갖는 스프링을 갖는 형태로 제작하였다. 댐퍼 시험체는 5개를 제작한 후, 이 댐퍼를 구조물에 배치하였을 때의 지진에 대한 에너지 소산량과 부재력을 검토하여 댐퍼의 안전성(Safety)를 검증하고자 한다.

• Journal of the Korean Institute of Gas
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• v.2 no.1
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• pp.59-65
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• 1998

Morphology and thermal properties of polyurethane synthesized from 4,4'-diphenylmethane diisocyanate (MDI), polyester polyol, and 1,4-butane diol are investigated using fourier transform infrared spectroscopy (FT-IR), differential scanning calorimeter (DSC), and dynamic mechanical thermal analysis (DMTA). From the FT-IR study, it is found that the stretching peaks of hydrogen bonded N-H and C=O are shifted to the low frequencies with the increase of hard segment content of the polyurethanes. The shift of the stretching peaks of hydrogen bonded N-H and C=O indicates that the degree of hydrogen bonding is increased. From the DSC study, it appears that the glass transition temperature ($T_g$) of the polyurethanes is increased with the increase of the hard segment content. Also, it is found that the polyurethanes investigated in this study have the homogeneous network structure due to the high functionality of the MDI. From the DMTA study, transition of the soft segment was not found. Therefore it is concluded that the polyurethanes investigated in this study have the one-phase morphology which is consistent with the DSC results.

• Journal of the Korea Convergence Society
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• v.10 no.3
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• pp.15-22
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• 2019

In this paper, we proposed a Hangeul detection method using structural features of histogram, consonant, and vowel to solve the problem of Hangul which is separated and detected consonant and vowel The proposed method removes background by using DoG (Difference of Gaussian) to remove unnecessary noise in Hangul detection process. In the image with the background removed, we converted it to a binarized image using a cumulative histogram. Then, the horizontal position histogram was used to find the position of the character string, and character combination was performed using the vertical histogram in the found character image. However, words with a consonant vowel such as '가', '라' and '귀' are combined using a structural characteristic of characters because they are difficult to combine into one character. In this experiment, an image composed of alphabets with various backgrounds, an image composed of Korean characters, and an image mixed with alphabets and Hangul were tested. The detection rate of the proposed method is about 2% lower than that of the K-means and MSER character detection method, but it is about 5% higher than that of the character detection method including Hangul.

• Journal of the Korean Wood Science and Technology
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• v.32 no.5
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• pp.29-38
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• 2004

In this study, we investigated the thermal properties of corn-starch filled polybutylene succinate-adipate (PBS-AD) bio-composites. Thermal analysis (TA) is used to describe the analytical method for measuring the chemical property and weight loss of composite materials as a function of temperature. The thermal stability of corn-starch was lower than that of pure PBS-AD. As corn-starch loading increased, the thermal stability and degradation temperature of the bio-composites decreased and the ash content increased. It can be seen that the degree of compatibility and interfacial adhesion of the bio-composites decreased because of the increasing mixing ratio of the corn-starch. As the content of corn-starch increased, there was no significant change in the glass transition temperature (T_g) and the melting temperature (T_m) for the bio-composites. The storage modulus (E') and loss modulus (E") of the corn-starch flour filled PBS-AD bio-composites were higher than those of PBS-AD, because of the incorporation of corn-starch increased the stiffness of the bio-composites. At higher temperatures, the decreased storage modulus (E') of bio-composites was due to the increased polymer chain mobility of the matrix polymer. From these results, we can expect that corn-starch has potential as a reinforcing filler for bio-composites. Furthermore, we recommend using a coupling agent to improve the interfacial adhesion between corn-starch and biodegradable polymer.

• Journal of the Earthquake Engineering Society of Korea
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• v.16 no.3
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• pp.1-12
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• 2012

In this study, an analysis method for the earthquake response of an offshore wind turbine model is developed, considering the effects of the fluid-structure-soil interaction. The turbine is modeled as a tower with a lumped mass at the top of it. The tower is idealized as a tubular cantilever founded on flexible seabed. Substructure and Rayleigh-Ritz methods are used to derive the governing equation of a coupled structure-fluid-soil system incorporating interactions between the tower and sea water and between the foundation and the flexible seabed. The sea water is assumed to be a compressible but non-viscous ideal fluid. The impedance functions of a rigid footing in water-saturated soil strata are obtained from the Thin-Layer Method (TLM) and combined with the superstructure model. The developed method is applied to the earthquake response analysis of an offshore wind turbine model. The method is verified by comparing the results with reference solutions. The effects of several factors, such as the flexibility of the tower, the depth of the sea water, and the stiffness of the soil, are examined and discussed. The relative significance of the fluid-structure interaction over the soil-structure interaction is evaluated and vice versa.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.771-776
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• 2020

In this study, the flexural/shear behavior characteristics of perfobond FRP-concrete composite beams using an FRP plate with perforated webs as formwork and reinforcement are analyzed through an analytical method. Compared with the existing experimental results, we have proved its usefulness and use it in future practice. When the nonlinearity is very large in this case, the nonlinear finite element analysis by an explicit method will be effective. The concrete damage plasticity (CDP) model adopted in this study is considered to be able to adequately simulate the nonlinear behavior of concrete, and the determination of several variable factors required in the model is compared with the experimental results and values used in the study. This recommendation will require review and adjustment for more diverse cases. The effect of the perfobond of the composite beam with perforated web is considered to be somewhat effective in terms of securing the initial stiffness, but in the case of the apex, it is considered that the cross-sectional loss and the effect of improving the bonding force should be properly arranged. The contact problem, such as slipping of the FRP plate and concrete, is considered to be one of the reasons that the initial stiffness is slightly larger than the test result, and the slightly difference from the experimental results is attributed to the separation problem between concrete and FRP after the peak.