• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.03a
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• pp.193-199
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• 2003

The most cultural heritages are composed of piled multi-block systems which are vulnerable to earthquakes. The stone of low height tends to slide when the excitation such as earthquake is applied and this sliding motion has effects on the whole response of the structure. In this study, analytical method of sliding motion of the piled multi-block systems considering horizontal rotation is developed and compared with shaking table test results. It is shown that the nonlinear analysis of sliding motion of multi-block system leads to satisfactory results.

• The Journal of Pediatrics of Korean Medicine
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• v.22 no.1
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• pp.149-162
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• 2008

Objectives The purpose of this study is to investigate that causes of motion sickness in oriental medicine. Methods The internal and external studies about motion sickness were searched Results and Conclusions The motion sickness is induced by conflict of balance system including vestibular, visual and proprioceptive system. The motion sickness is more common in female and in children between 2 and 12 years old. In western medicine, antihistamine and anticholinergic has been used for treatment of motion sickness, but these anti-motion sickness drug turn out to be not a perfect solution and have several side effects. On the other hands, In oriental medical terminology, there is no words equivalent to the "motion sickness", but we consider the motion sickness as state with dizziness, nausea and vomiting. The motion sickness can be induced by either internal or external causes and the internal causes can thought to be a constitutional factor of an individuals, and the general transportation can be an external cause. The important internal cause is a dysfunction of the spleen, stomch(脾胃不調), retention of phlegm and fluids(痰飮), and deficiency of the kidney jing(腎精不足). The wind(風) and fire(火) in the upper part of the body, especially in the head, also can be an important cause of the motion sickness.

• Wind and Structures
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• v.14 no.6
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• pp.499-515
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• 2011

Low-frequency building vibration is known to induce symptoms of motion sickness in some occupants. This paper examines how the adoption of a theory of motion sickness, in conjunction with a dose-response model might inform the real-world problem of managing and designing standards for tall building motion sway. Building designers require an understanding of human responses to low-dosage motion that is not adequately considered by research into motion sickness. The traditional framework of Sensory Conflict Theory is contrasted with Postural Instability Theory. The most severe responses to motion (i.e., vomiting) are not experienced by occupants of wind-excited buildings. It is predicted that typical response sets to low-dosage motion (sleepiness and fatigue), which has not previously been measured in occupants of tall-buildings, are experienced by building occupants. These low-dose symptoms may either be masked from observation by the activity of occupants or misattributed to the demands of a typical working day. An investigation of the real-world relationship between building motion and the observation of low-dose motion sickness symptoms and a degradation of workplace performance would quantify these effects and reveal whether a greater focus on designing for occupant comfort is needed.

• Earthquakes and Structures
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• v.10 no.5
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• pp.1233-1251
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• 2016

In this paper, it is aimed to determine the stochastic response of a suspension bridge subjected to spatially varying ground motions considering the geometric nonlinearity. Bosphorus Suspension Bridge built in Turkey and connects Europe to Asia in Istanbul is selected as a numerical example. The spatial variability of the ground motion is considered with the incoherence, wave-passage and site-response effects. The importance of site-response effect which arises from the difference in the local soil conditions at different support points of the structure is also investigated. At the end of the study, mean of the maximum and variance response values obtained from the spatially varying ground motions are compared with those of the specialised cases of the ground motion model. It is seen that each component of the spatially varying ground motion model has important effects on the dynamic behaviour of the bridge. The response values obtained from the general excitation case, which also includes the site-response effect causes larger response values than those of the homogeneous soil condition cases. The variance values calculated for the general excitation case are dominated by dynamic component at the deck and Asian side tower. The response values obtained for the site-response effect alone are larger than the response values obtained for the incoherence and wave-passage effects, separately. It can be concluded that suspension bridges are sensitive to the spatial variability of ground motion. Therefore, the incoherence, the wave-passage and especially the site-response effects should be considered in the stochastic analysis of this type of engineering structures.

• Structural Engineering and Mechanics
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• v.43 no.5
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• pp.637-655
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• 2012

In this study, stochastic responses of a cable-stayed bridge subjected to the spatially varying earthquake ground motion are investigated by the finite element method taking into account soil-structure interaction (SSI) effects. The considered bridge in the analysis is Quincy Bay-view Bridge built on the Mississippi River in between 1983-1987 in Illinois, USA. The bridge is composed of two H-shaped concrete towers, double plane fan type cables and a composite concrete-steel girder deck. In order to determine the stochastic response of the bridge, a two-dimensional lumped masses model is considered. Incoherence, wave-passage and site response effects are taken into account for the spatially varying earthquake ground motion. Depending on variation in the earthquake motion, the response values of the cable-stayed bridge supported on firm, medium and soft foundation soil are obtained, separately. The effects of SSI on the stochastic response of the cable-stayed bridge are also investigated including foundation as a rigidly capped vertical pile groups. In this approach, piles closely grouped together beneath the towers are viewed as a single equivalent upright beam. The soil-pile interaction is linearly idealized as an upright beam on Winkler foundation model which is commonly used to study the response of single piles. A sufficient number of springs on the beam should be used along the length of the piles. The springs near the surface are usually the most important to characterize the response of the piles surrounded by the soil; thus a closer spacing may be used in that region. However, in generally springs are evenly spaced at about half the diameter of the pile. The results of the stochastic analysis with and without the SSI are compared each other while the bridge is under the sway of the spatially varying earthquake ground motion. Specifically, in case of rigid towers and soft soil condition, it is pointed out that the SSI should be significantly taken into account for the design of such bridges.

• Journal of the Society of Naval Architects of Korea
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• v.50 no.5
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• pp.273-281
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• 2013

In this paper, the effects of bow deck shape on the green water are studied by numerical and experimental method. Varying the deck shapes to triangular, elliptic and circular, the thickness and advancing velocity of green water leading edge are compared using numerical method. Also the motion, the pressure on the vertical wall and the height on the deck of green water are compared among the three bow deck shapes in the heave and pitch motion free condition by experimental method. To remove the effects of the difference of motions among the deck shapes, numerical simulations are performed varying the deck shape with the same motion. In the same motion condition, smallest impulsive pressure occurred in the condition of elliptic deck shape.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.5
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• pp.1003-1015
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• 1988

Damping information is required to analyse heat exchangers for flow-induced vibration. The most important energy dissipation mechanisms in heat exchanger tubes are related to the dynamic interaction between tube and support. In liquids, squeeze-film damping is dominat. Simple experiments were carried out of a two-span tube with one intermediate support to investigate the effects of tube-support parameters, such as: tube-support thickness, diametral clearance, tube eccentricity, tube span length, location of tube-support, and nature of dynamic interaction between tube and tube-support. The results show that squeeze-film damping is much larger for lateral-type motion than for rocking-type motion at the support. Eccentricity was found to be very important. Diametral clearance, support thickness and frequency are also very relevant. The effects of these parameters on squeeze-film damping are formulated and proposed in a semi-empirical expression.

• Journal of Ocean Engineering and Technology
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• v.24 no.5
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• pp.16-21
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• 2010

During the loading/offloading operation of a liquefied natural gas carrier (LNGC) that is moored in a side-by-side configuration with an offshore plant, sloshing that occurs due to the partially filled LNG tank and the interactive effect between the two floating bodies are important factors that affect safety and operability. Therefore, a time-domain software program, called CHARM3D, was developed to consider the interactions between sloshing and the motion of a floating body, as well as the interactions between multiple bodies using the potential-viscous hybrid method. For the simulation of a floating body in the time domain, hydrodynamic coefficients and wave forces were calculated in the frequency domain using the 3D radiation/diffraction panel program based on potential theory. The calculated values were used for the simulation of a floating body in the time domain by convolution integrals. The liquid sloshing in the inner tanks is solved by the 3D-FDM Navier-Stokes solver that includes the consideration of free-surface non-linearity through the SURF scheme. The computed sloshing forces and moments were fed into the time integration of the ship's motion, and the updated motion was, in turn, used as the excitation force for liquid sloshing, which is repeated for the ensuing time steps. For comparison, a sloshing motion coupled analysis program based on linear potential theory in the frequency domain was developed. The computer programs that were developed were applied to the side-by-side offloading operation between the offshore plant and the LNGC. The frequency-domain results reproduced the coupling effects qualitatively, but, in general, the peaks were over-predicted compared to experimental and time-domain results. The interactive effects between the sloshing liquid and the motion of the vessel can be intensified further in the case of multiple floating bodies.

• Korean Institute of Interior Design Journal
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• v.23 no.5
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• pp.25-32
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• 2014

The purpose of this study is to analyze the expression method and visual characteristics of material utilized the lighting in terms of a visual aspect. The method of study is to establish standards for analysis and to classify type of visual effect and expression of that focused on preliminary study. And It is to grasp the visual expression characteristics of new materials. through analysis standards. The results of the study are as follows. First, 'decorativeness', 'symbolization', 'motion-images' and 'interactivity' were selected as the type of visual expression through the precedent studies. And it was classified the visual effects as 3 types like 'a light-emitting effect', 'steric effects' and 'movement effect'. Second, We could know that 'light-emitting effect' was expressed in 7-new materials, 'three-dimensional effect' was expressed in 3-new materials, and 'motion effect' in 4-new materials. Through that. We could know that the new materials represented with 'light-emitting effect' are much more than the other new materials. Third, the results of this study show that 'decorativeness' in the visual types was appeared to 'light-emitting effect' and 'three-dimensional effect'. 'symbolization' to 'light-emitting effect' and 'motion effect', 'motion-images' to 'three-dimensional effect' and 'motion effect' and 'interactivity' to 'light-emitting effect', 'three-dimensional effect' and 'motion effect'. And It was appeared to three effects in 'interactivity'. We could know that it is more effective to be presented the visual effect simultaneously to communication with the visual perception.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.19 no.1
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• pp.55-61
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• 2013

Background: The purpose of this study was to investigate the immediate effects of mulligan's straight leg raise with traction technique on angle of passive straight leg raise and length of hamstring muscle in patients with low back and radiate pain. Methods: Thirty one subjects participated in this study. The subjects were assigned to either the low back pain group (n=17) or the radiate pain group (n=14). Subjects in both groups received 3 times mulligan's straight leg raise with traction. All subjects were examined for the range of motion of lower extremity. The range of motion of lower extremity was composed of angle on straight leg raise and 90-90 straight leg raise. The range of motion of lower extremity was measured using a goniometer. Results: After 3 times of mulligan's straight leg raise with traction, significant improvements on the angle of straight leg raise and 90-90 straight leg raise were observed in the both groups (p<.05). However, there are no significant difference was observed between groups. Conclusion: These results suggest that mulligan's straight leg raise with traction provides an immediately effective in range of motion of lower extremity in patients with low back pain as well as radiate pain. Although more research is required on the effects of long-term mulligan's straight leg raise with traction on range of motion of lower extremity, our results can be useful to establish the standard parameters for range of motion of lower extremity in the clinical setting.