• International Journal of High-Rise Buildings
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• v.6 no.3
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• pp.227-235
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• 2017

This paper describes some of the challenges for structural design of a mid-story seismic isolated high-rise building, which is located near Tokyo station, completed in 2015. The building is a mixed-use complex and encompasses three volumes: one substructure including basement and lower floors, and a pair of seismic isolated superstructures on the substructure. One is a 136.5m high Main Tower (office use), and the other is a 98.5 m high South Tower (hotel use). The seismic isolation systems are arranged in the $3^{rd}$ floor of the Main Tower and $5^{th}$ floor of the South Tower, so that we call this isolation system as the mid-story seismic isolation. The primary goal of the structural design of this building was to secure high seismic safety against the largest earthquake expected in Tokyo. We adopted optimal seismic isolation equipment simulated by dynamic analysis to minimize building damage. On the other hand, wind-induced vibration of a seismic isolated high-rise building tends to be excited. To reduce the vibration, the following strategies were adopted respectively. In the Main Tower with a large wind receiving area, we adopted a mechanism that locks oil dampers at the isolation level during strong wind. In the South Tower, two tuned mass dampers (TMDs) are installed at the top of the building to control the vibration. In addition, our paper will also report the building performance evaluated for wind and seismic observation after completion of the building. In 2016, an earthquake of seismic intensity 3 (JMA scale) occurred twice in Tokyo. The acceleration reduction rate of the seismic isolation level due to these earthquakes was approximately 30 to 60%. These are also verified by dynamic analysis using observed acceleration data. Also, in April 2016, a strong wind exceeding the speed of 25m/s occurred in Tokyo. On the basis of the record at the strong wind, we confirmed that the locking mechanism of oil damper worked as designed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.4
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• pp.537-545
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• 2018

Determination of the time parameters such as the travel time in the design flood is very important. The travel time is mainly used for flood and river management, and the travel time of non flood season is used for maintenance flow and management of the river. Estimation of travel time for natural rivers is mainly based on the geomorphological factors of the basin. In addition to the topographical factors, the travel time is calculated by considering the factors of the runoff curve, velocity and rainfall intensity. However, there is no study on the estimation of travel time considering both the rainfall condition and the soil moisture accounting by the frequency period. Therefore, the travel time calculation is divided into the case of setting the Hwanggang Dam and the Imjin bridge water level station of Imjin river as the natural river considering rainfall condition by the frequency period and the soil moisture accounting, and the case of traveling the Imjin bridge water level station according to the condition of outflow of the Hwanggang Dam. For the sections set as natural rivers, the results were verified by comparing with the newly developed travel time calculation method. Based on the results, the travel times of the Hwanggang Dam outflow conditions were calculated. The time to travel in this study can be secured flood control of the Imjin river basin and time to prepare for danger when outflowing the the Hwanggang Dam.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.3
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• pp.267-272
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• 2012

Dental professionals are exposed to various occupational risks, among which the problem of hearing damage has been newly revealed. There have been some researches reporting that noise occurring in a dental office exceeds the Occupational Safety and Health Act (OSHA) Standards. Especially, the pediatric dentists are repeatedly exposed to an additional noise source called the crying sound of children in addition to all kinds of noises from dental instruments. Accordingly, this study intended to investigate the noise environment likely to affect pediatric dentists and to examine the possibility of resultant hearing damages. The level of noise was measured respectively, when various dental instruments (ultrasonic scaler, high-speed handpiece, low-speed handpiece) are operated, when children are crying, and when both occasions take place simultaneously (from the distance of 30 cm) with a portable noise meter. And the daily duration of pediatric dentists exposed to the noise environment was surveyed. The results were compared with the standard value of noise threshold of NIOSH, OSHA, and that of hearing damage of CRA News letter respectively. Considering the intensity and exposure time, the noise environment of pediatric dentists exceeds the allowable noise threshold values. Even only one exposure to crying child was likely to lead to permanent hearing damage. Comparatively, pediatric dentists have a higher risk for occupational hearing damages, and some active measures are thought highly desirable to minimize it.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.1
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• pp.34-42
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• 2011

It's been reported that the global warming effect has invoked the ever increasing typhoon intensity and long-term sea level rise which jointly cause severe wave overtopping over breakwaters or shore dykes. A simple measure to cope with this undesirable change may be just to increase the crest height of the dykes and breakwaters. This is surely effective to prevent wave overtopping, but it also decreases the seaward visibility of coastal waterfront. In this paper, a dynamic deformable rubber membrane parapet which not only reduces wave overtopping in storm period but also secures seascapes in normal days is presented. Several optimal configurations of the parapet are proposed. Through numerical analyses using a nonlinear finite element model and hydraulic experiments, the air controlled expansion and contraction of the parapets, their behavior against wave overtopping and structural stability are investigated.

• The KIPS Transactions:PartB
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• v.17B no.5
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• pp.363-374
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• 2010

In this paper, we propose the method for extracting Homogeneity Threshold($H_T$) and for segmenting homogeneous regions by USRG(Unseeded Region Growing) with $H_T$. The $H_T$ is a criterion to distinguish homogeneity in neighbor pixels and is computed automatically from the original image by proposed method. Theoretical background for proposed method is based on the Otsu's single level threshold method. The method is used to divide a small local part of original image int o two classes and the sum($\sigma_c$) of standard deviations for the classes to satisfy special conditions for distinguishing as different regions from each other is used to compute $H_T$. To find validity for proposed method, we compare the original image with the image that is regenerated with only the segmented homogeneous regions and show up the fact that the difference between two images is not exist visually and also present the steps to regenerate the image in order the size of segmented homogeneous regions and in order the intensity that includes pixels. Also, we show up the validity of proposed method with various results that is segmented using the homogeneity thresholds($H^*_T$) that is added a coefficient ${\alpha}$ for adjusting scope of $H_T$. We expect that the proposed method can be applied in various fields such as visualization and animation of natural image, anatomy and biology and so on.

• The Journal of Engineering Geology
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• v.30 no.3
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• pp.327-345
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• 2020

The effects of ground vibration on lava tubes during construction were studied to aid design of management and preservation measures for lava tubes. Ground conditions were assessed by RMR (Rock mass rating) and Q-system classifications for the Geomunoreum lava tubes, and vibration velocity was measured during in situ blasting tests in the Manjanggul and Yongcheondonggul lava tubes. Results indicate that the higher the rock quality, the greater the effect of vibration, although there is no clear linear relationship due to ground heterogeneity. A relationship derived between vibration velocity (PPV) and intensity (dB(V)) on the basis of blasting tests indicates that a vibration level of < 0.285 cm/sec meets the regulatory limit of 0.371 cm/sec and 65 dB(V) during daytime, and 0.285 cm/sec and 60 dB(V) during night. For blasting vibrations, square- and cube-root scaled distances are linearly correlated, with R² ≥ 0.76. On the basis of this correlation, explosive-charge weights meeting the 0.2 cm/sec vibration criterion for cultural heritage were estimated to be 2.88 kg at 50 m distance, and 11.52 kg at 100 m.

• Korean Journal of Food Science and Technology
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• v.49 no.1
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• pp.72-79
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• 2017

This study was conducted to investigate the effects of a low-sodium label on acceptability and sensory attributes of a dipping sauce for fried pork cutlets. Two sauce samples, CON (normal sodium level) and LOW-Na (50% sodium level), were evaluated. Consumers (n=77) rated expectations and actual perception of overall liking, purchase intent, and intensities of saltiness, sweetness, sourness, fruit flavor, and degree of flavor balance without and with a carrier (fried pork cutlet) in blind and informed settings. In the informed test, CON labeled as Low-Na (PLACEBO) was additionally tested to examine the placebo effect of information. The low-sodium labeling significantly increased the expected liking and purchase intent, but decreased the expected saltiness. However, the label did not influence actual liking or purchase intent. A significant decrease in actual saltiness was observed only in Low-Na, not in PLACEBO, indicating the label is influential only when actual perception matched the expectation.

• Journal of Acupuncture Research
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• v.21 no.5
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• pp.45-58
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• 2004

It is well known that both of acupuncture and moxibustion are effective for treatment of human disease. For years, they have been utilizing a electro-acupuncture (EA) and moxibustion in attempt to manage gastric symptom. However, the data of combined EA and moxibustion on clinical effectiveness is conflicting and the action of combineAd acupoints is not well known. BL21 and ST36 which belong to bladder Meridian and stomach meridian are acupuncture points frequently used for healing gastrointestinal disease in oriental medicine. The present study was conducted to see the effects produced by combined electro-acupuncture(EA) and moxibustion using BL21 and ST36 on serum gastrin level in rats. In experiment, male Spraque-Dawley rats(body wt 140-160g) were selected. EA (2 Hz, intensity ; 10 times muscle twitch threshold) was applied for 30 minutes to ST36 under halothane anesthesia. Moxibustion($1.6{\pm}0.3 mg$, 5 times of a day) was applied during 3 days to BL21 under halothane anesthesia. Synergy effects of combined EA and moxibustion might be in according to stimulated method and used acupoints. The change of serum gastrin levels produced by combined EA and moxibustion is shown after vagotomy. These data suggested that many factors, such as the selection of acupoints, the stimulated EA methods, are capable of affecting combined EA and moxibustion effects and those effects may be not related with nervous system.

• Physical Therapy Korea
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• v.19 no.4
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• pp.24-31
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• 2012

The aim of this study was to investigate the effectiveness of self-stretching exercises for iliotibial band (ITB) (Side-lying; right hip and knee were flexed to support the pelvis while left hip was extended and adducted, Standing A; side-bending of the trunk on standing with crossed leg, Standing B; same as Standing A, except the hands were clasped overhead and shifted right side, and Standing C; same as Standing B, except moving the arms diagonally downward) to help determine the most effective self-stretching method to stretch ITB. Twenty-one healthy subjects who do not have ITB shortness from Yonsei University (14 men and 7 women) between the ages of 18 to 28 years voluntarily participated. Ultrasound was performed to measure the thickness of the ITB between the long axis of the ITB and the level parallel to the lateral femoral epicondyle during four self-stretching exercises. All data were found to approximate a normal distribution. We used a one-way repeated-measures analysis of variance (ANOVA) to compare the thickness of the ITB among all self-stretching exercises. The level of significance was set at ${\alpha}$=.05. The ANOVA was followed by Bonferroni's correction. The overall mean of ITB thickness was $1.14{\pm}.4$ mm (${\pm}$ standard deviation) in resting status. The change in the ITB thickness in percentages between the tested position of each self-stretching exercises and resting status was significant (p<.05) (Side-lying $26.62{\pm}10.18%$ with 95% confidence interval [CI]=21.99~31.25%; Standing A $29.46{\pm}16.19%$ with 95% CI=22.09~36.84%; Standing B $44.06{\pm}14.82%$ with 95% CI=37.31~50.81%; Standing C $53.76{\pm}12.1%$ with 95% CI=48.25~59.29%). Results indicated significant differences among four self-stretching exercises except Side-lying versus Standing A (p<.01). Based on these findings, the Standing C self-stretching exercise was the most effective in stretching the ITB thickness among four types of ITB self-stretching exercises. Additionally, the Side-lying self-stretching exercise using gravity to stretch the ITB is recommended as a low-load (low-intensity), long-duration stretch.

• The Journal of the Korea Contents Association
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• v.12 no.12
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• pp.771-778
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• 2012

The purpose of the study was to investigate the effects of the after school sports club activity on the school life satisfaction in the middle school students. A total of 640 middle school students in D city at september, 2012 were selected using the stratified cluster random sampling method. The survey instrument was utilized for the current study. Independent variables included participation or non-participation and the level of participation(frequency, duration, intensity), and dependent variables contained the school life satisfaction(classmate, teacher, learning activity, school event, and following rules). After the pilot test, the frequency analysis, exploratory factor analysis, reliability analysis, t-test, correlation analysis, and regression analysis were conducted with the SPSS 18.0 program. Main findings were as followed: First, the school life satisfaction of the middle school students participating in the after school sports club activity was higher than it of non-participants. Second, the level of participation in the after school sports clubs activity had an influence on the school life satisfaction. In detail, satisfaction with the school life of students who frequently, long, and intensively participated in the after school sports club activity was higher.