• Journal of Advanced Marine Engineering and Technology
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• 제19권3호
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• pp.42-49
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• 1995

In this study, the optimum structural modification of the L-type structure by shape changes is suggested. The vibration characteristics of L-type structure are analyzed by the sub-structure synthesis method, and the coordinte sensitivities of each sub-structure are calculated and the change quantities of the positions to be modified are suggested by using the coordinate sensitivities. The results obtained are as follows : 1. The sensitivities of the natural frequency could be calculated by the sensitivity analysis. 2. The change quantities of the position to be modified could be suggested by the optimum structural modification method. 3. The developed program could reduce the process and time of computation, since the sensitivity was directly calculated by differential method, not finite difference method.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 가을 학술발표회 논문집
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• pp.550-557
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• 2004

In this paper, structural damage in PSC bridges is monitored by using model-based damage detection methods. First numerical experiments on the test structure are described. Dynamic responses of the test structures are obtained fur several damage scenarios. The change in natural frequency and the change in nude shape curvature are selected as features to represent the states of the structure. Next a damage localization algorithm from monitoring the changes in natural frequency is outlined. Also, the damage localization algorithm from monitoring the changes in nude shapes is outlined. Finally, the damage localization algorithms are used to predict damage in the test structure. The results of the analysis indicate that the model-based damage detection methods correctly predicted damage in the test structure.

• 한국정밀공학회지
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• 제27권7호
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• pp.49-54
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• 2010

The cryogenic ball milling was performed on carbon nanotubes (CNTs) at an extremely low temperature to increase the dispersion of CNTs. The effects of milling speed and time on the deagglomeration and structural changes of CNTs were studied. FESEM was used to analyze the dispersion and the change of particle size before and after milling process. Transmission electron microscopic (TEM) analysis was also investigated the effect of cryogenic ball milling on the morphological characteristics of CNTs. The structural changes by the cryogenic ball milling process were further confirmed by x-ray diffraction (XRD) and Raman spectroscopic analysis. The results showed that the agglomeration of CNTs was significantly reduced and amorphous structure was observed at high milling speed. However, the milling time has no great effect on the dispersion property and structural change of CNTs compared with milling speed.

• 한국산학기술학회논문지
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• 제11권11호
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• pp.4075-4079
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• 2010

본 논문의 목적은 현재 도기가스, 상하수도 및 화학배관 파이프 등의 플라스틱 배관 공사에서 사용되는 파이프 융착기를 3차원 설계하고 융착 시 발생하는 문제점을 해결하기 위하여 구조해석에 의한 검증작업을 거쳐 구조를 개선한다. 현장에서 파이프 융착 작업 시 융착기 크램프에 크랙이 발생하므로 이를 개선하기 위하여 융착기의 구조를 변경하는 설계치를 제시함으로서 작업의 효율성을 높이고 기술경쟁력을 향상시킨다.

• 한국세라믹학회지
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• 제54권5호
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• pp.406-412
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• 2017

$70V_2O_5-10Fe_2O_3-13P_2O_5-7B_2O_3$ glasses were prepared to study the electrical conductivity and catalytic properties of the structural change with crystallization. The structural changes were analyzed by determining the molecular volume from the sample density; using X-Ray Diffraction (XRD) analysis, which indicated that $V_2O_5$, $VO_2$ and $B_2O_3$ crystals in heat-treated more than 1h samples. Especially a new crystalline phase of non-stoichiometric $Fe_{0.12}V_2O_5$ was formed after 6 h heat treatment. The V-O bonding change after crystallization was analyzed by Fourier Transform Infrared Spectroscopy (FTIR); V ion change from $V^{5+}$ to $V^{4+}$ was shown by XPS. Conductivity and catalytic properties were examined based on the polaronic hopping of V and Fe ions, which exhibited different valence states with crystallization.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2005년도 춘계 학술발표회 논문집
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• pp.672-679
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• 2005

Damage detection is a very active research field, in which significant efforts have been invested in recent years. In this paper, analysis using structural stiffness estimation for damage detection is presented and compared to other methodologies. By using a cantilever analytical beam model, it is shown here that not only location but also the amount of damage in structure can be predicted from the ratio of change in stiffness. Damage detection experiment in real beam specimen on is also peformed and the results are compared.

• 소음진동
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• 제9권6호
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• pp.1145-1151
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• 1999

Sensitivity analysis and structural modification technique are used to reduce the interior noise of a passenger car. The sensitivity analysis for the noise level at the rear seat shows that the stiffness change at the front lower member and the rear roof rail are sensitive. Using the structural modification method, we verified that the reinforcements at those members decrease the noise transfer function from the body to the rear seat. The combined application of the sensitivity analysis and structural modification method can decrease the noise level effectively.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2001년도 학술발표회 논문집(Proceedings of the Korean Textile Conference) 상
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• pp.123-126
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• 2001

• 한국심리학회지 : 문화 및 사회문제
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• 제14권1호
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• pp.19-45
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• 2008

본 연구는 급격한 사회변동의 대한 주관적 지각이 정신건강에 유의한 영향을 미치며 이 과정에서 두 가지 대처자원인 개인적 자원과 사회적 자원이 문화적으로 다른 효과를 갖는다는 가설을 한국과 미국표본을 비교함으로써 검증하였다. 한국과 미국에서 수행된 설문자료를 다표본 구조방정식 모형으로 비교 분석한 결과 첫째, 사회변동 속도의 지각이 사회변동의 평가라는 매개과정을 통해서 주관적 안녕감에 영향을 미침을 발견하였고, 둘째 개인적 자원은 미국표본에서 그리고 사회적 자원은 한국표본에서 스트레스의 대처에 더 큰 효과를 가짐을 각각 발견하였다. 사회변동의 주관적 지각이라는 새로운 사회적 스트레스 요인에 대한 논의가 포함되었다.

• 한국공간구조학회논문집
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• 제19권2호
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• pp.83-90
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• 2019

Most of the variable shading devices are installed outdoors, so they are greatly affected by structural safety due to external climate change, wind, rain, and snow. Especially, due to strong wind such as typhoons, safety problems may occur due to the dropout of the device. Therefore, it is necessary to secure the structural safety against the wind. Therefore, it is necessary to analyze the structural behavior of the windshield to evaluate the structural safety of the variable sunshade device. In this study, we analyze the wind pressure applied to the shading material according to the change of the length of the variable shading device, and apply it to the calculation of the wind load for the structural design of the variable shading device. The CFD (Computational Fluid Dynamic) analysis of the structure of the sample was used to analyze wind pressure magnitude and distribution. In order to estimate the wind pressure, the maximum wind loads of the static and negative pressures acting on the structure were analyzed from numerical simulation results.