• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.12
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• pp.911-917
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• 2003

Vibration localization characteristics of open loop repeated mistuned structures are investigated. The mistuning often creates significant response discrepancies among subcomponents of the repeated structures. As a result of the discrepancies, critical fatigue problems often occur in repeated structures. Therefore. it is of great importance to predict the vibration response of the mistuned repeated structures accurately in this Paper, a simplified model for an open-loop repeated structure is introduced and dimensionless parameters that influence the localization characteristics are identified. The effects of the parameters on the localization characteristics are investigated through numerical study.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.11
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• pp.556-560
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• 2004

In this paper, thermal and structural properties of epoxy/elastomer blend were measured by DSC, TGA and FESEM. Specimens were made of dumbbell forms by the ratio of 5, 10, 15, and 20[phr] by changing elastomer content. The measuring temperature ranges of DSC were from -20[℃] to 150[℃] and heating rate was 4[℃/min]. And the measuring temperature ranges of TGA were from 0[℃] to 800[℃], and heating rate was 5[℃/min]. Also we observed structure of specimens through FESEM with magnification of 1000 times and voltage of 15[kV] by breaking quenched specimens. As experimental results, we could know that thermal and structural properties were improved according to decrease of elastomer content. Because it increased glass transition temperature, high temperature and structure of elastic epoxy.

• 한국기계연구소 소보
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• s.19
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• pp.5-14
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• 1989

Analytical and experimental studies are performed to identify the longitudinal vibration characteristics of elevator system such as the natural frequencies, and the magnification factor at resonance. In the analytical study, a computer program is developed to analyze the vibration characteristics of elevator with varing rope length of elevtor, stiffenss of thimble rod spring, and excitation frequency. The shorter rope length and the stiffer thimble rod spring make the natural frequencies of elevator higer. The resonance at the first natural frequency spreads over the entire travelling range, whereas, that at the second one ranges relatively short, region. The first natural frequencies of the Gald-Star Twin Building and the Korea Trading Center Building obtained by the experiment are overall in good agreement with the analysis result..

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.522-529
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• 2006

Running train is one of the most main factor for railway bridge vibration. The repeated forces with equidistant axles cause the magnification of dynamic responses which relates with maintenance of the track structure and structure-borne noises. The noise problem is one of the most important issues in services of light rail transit system which usually passes through towns. The noise of railway bridges can be divided into the noise from track-vehicle system and structure-borne noises. In the present study, The vibration and noise of the LRT bridge will be investigated with utilizing dynamics responses from moving train as input data for noise analysis.

• Structural Engineering and Mechanics
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• v.8 no.2
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• pp.137-150
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• 1999

This paper presents a numerical study on the flat plates in deep basements, subjected to floor load and in-plane compressive load due to soil and hydraulic lateral pressure. For nonlinear finite element analysis, a computer program addressing material and geometric nonlinearities is developed. The validity of the numerical model is established by comparison with existing experiments performed on plates simply supported on four edges. The flat plates to be studied are designed according to the Direct Design Method in ACI 318-95. Through numerical study on the effects of different load combinations and loading sequence, the load condition that governs the strength of the flat plates is determined. For plates under the governing load condition, parametric studies are performed to investigate the strength variations with reinforcement ratio, aspect ratio, concrete strength, and slenderness ratio. Based on the numerical results, the floor load magnification factor is proposed.

• Journal of Fashion Business
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• v.6 no.4
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• pp.32-45
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• 2002

The purpose of this study is, to renew understanding the aesthetic value of a ruff collar and to expand the border of creation in designing as the source of inspiration being applied to an retro style by inquiring various ruff collars re-illuminated in the present-day fashion trend. The ruff collar investigated through the above historical contemplation became the source of inspirations in the current retro trend and was variously modified in modern fashion. In the 1980s, we can find a dignified and feminine image in graceful and exquisite suits or dresses. Especially, the spanish round ruff of the 2st period appeared on works by a lot of designers. From the application by designers like John Galliano in the latter half of the 80s, we can be well aware that the meaning of decoration was newly altered. In the 1990s, the ruff collar was shown in various fashion style, but it was what was reborn as a factor of modern fashion through a liberal compromise and harmony. Various style was shown from exaggeratedly swelling one to smaller one, which were more diversely applied than that of the 80s. A Medici collar and a Queen Elizabeth collar were also displayed being fitted to a modern sense by Vivienne Westwood and Louis F raud. A ruff in the 2000s was settled as a factor of modern fashion, exposing on works of designers more often than in the 1980s and 90s. The spanish round ruff appeared on garments, while a Medici collar and a Queen Elizabeth collar went out of sight. A new form of the ruff was regenerated by extreme magnification and simplification, and several designers like Issey Miyake and Alexander Mcqueen brought forward a new way in materials and technical skills. According to this research, a ruff collar developed as a fashion factor which characterizes a certain period of time, reflecting the aesthetical sense of Renaissance and turning into various and distinct forms. Afterwards, it exerted influence on modern fashion. This is offering the source of inspiration to contemporary designers.

• Journal of the Earthquake Engineering Society of Korea
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• v.18 no.3
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• pp.133-140
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• 2014

The friction damper can be used for improving the seismic resistance of existing buildings. The damper is often installed in bracing members. The energy dissipation capacity of the damping systems depends on the type of the structure, the configuration of the bracing members, and the property of dampers. In Korea, there are numerous low- to mid-rise reinforced concrete moment frames that were constructed considering only gravity loads. Those frames may be vulnerable for future earthquakes. To resolve the problem, this study developed a toggle bracing system with a high density friction damper. To investigate the improvement of reinforced concrete frames after retrofit using the developed damped system, experimental tests were conducted on frame specimens with and without the damped system. The results showed that the maximum strength, initial stiffness and energy dissipation capacity of the framed with the damped system were much larger than those of the frame without the damped system.

• The Journal of Engineering Geology
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• v.25 no.2
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• pp.165-178
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• 2015

Physical and chemical weathering degrades rock, affecting its structural properties and thus the stability of stone buildings or other structures. Confocal laser scan microscopy (CLSM) is used here to observe temporal changes in the surface roughness of rock samples under simulated accelerated weathering. Samples were pressurized to 50, 55, or 70 MPa using a pressure frame, and subjected to freeze/thaw cycling controlled by a thermostat. The temperature was cycled from -20℃ to 40℃ and back. After each 20 cycles, CLSM was used to assess the change in surface roughness, and roughness factors were calculated to quantify the progression of the surface condition over time. Variations in cross-section line-roughness parameters and surface-roughness parameters were analyzed for specific parts of the sample surfaces at 5× and 50× magnification. The result reveals that the highest and lowest values of the roughness factors are changed according to elapsed time. Freezing/thawing at high pressure caused larger changes in the roughness factor than at low pressure.

• Women's Health Nursing
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• v.10 no.2
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• pp.162-170
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• 2004

Purpose: The purpose of this study was to differentiate between women with three perimenstrual symptom severity patterns : premenstrual syndrome(PMS), premenstrual magnification(PMM), and low symptom(LS), and to explore the related dietary factors to premenstrual symptoms. Method: Women were asked to keep a diary record of perimenstrual symptoms and food intake for 50 days. Result: Symptom patterns were defined for 26 among 38 women ; Eight(21.1%) demonstrated a PMS pattern, three(7.9%) demonstrated a PMM pattern, and fifteen(39.5%) exhibited a LS pattern. There were significant differences in symptom scores during the premenstrual phase($x^2=19.30$, p=.000), menstrual phase($x^2=13.32$, p=.001), and post menstrual phase($x^2=9.93$, p=.007) for three groups. Protein, vit E, vit C, niacin, folic acid, and phosphorus in the premenstrual phase, and energy, and vit B6 in the menstrual period were significantly different between the three groups. Among dietary compositions, amino acids, lipids, fatty acids, saturated fatty acids, natrium, vit B6, niacin, and vit E were negatively related to PMS symptoms. Conclusion: Pattern of perimenstrual symptoms should be differentiated for individualized PMS management. As a more efficient diet assessment for PMS women, randomized nutritional analysis during the 3 phases of the menstrual cycle should be done and a replication study is necessary with a larger sample.

• Journal of Korean Society of Steel Construction
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• v.12 no.1 s.44
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• pp.103-110
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• 2000

The suspension bridge is divided by an earth anchor and a self-anchor type according to the anchorage type. This study is to evaluate the dynamic effect of moving vehicles to suspension bridges. The results were presented with the dynamic magnification factor (DMF) by the effect of vehicle speed and weight according to the anchorage type. The vehicle model has 6 degrees of freedom to idealize nonlinear multi-leaf suspensions and elastic tires of tractor-trailer. The bridge was modelled with the 3-dimensional frame element and 3-dimensional elastic catenary cable element. The condition of deck surface is considered using the actual road spectra.