• Journal of The Korean Society of Integrative Medicine
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• v.11 no.3
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• pp.1-10
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• 2023

Purpose : This study was conducted to determine the effect of intervention using a smartphone application on abdominal muscle thickness and maximum voluntary ventilation when conducting pelvic floor muscle exercise (PFME). Methods : This study was performed on 14 subjects. They were divided into two groups; PFME using smartphone application (n=7), common PFME (n=7). Both of group executed the exercise 5 times a week for 1 weeks. Abdominal muscle thickness was measured using ultrasound. Maximum voluntary ventilation was measured using a spirometer. The smartphone application used the paid version of Kegel trainer. This material was analyzed by the paired t-test to compare differences on each group and the independent t-test to compare between the two groups. Results : The PFME group using the smartphone application showed a significant increase in the transverse abdominis and internal oblique muscles (p<.05). The common PFME group showed a significant increase in the internal oblique muscle (p<.05). There was no significant difference in variation of the muscle thickness between the two groups (p>.05). The PFME group using the smartphone application showed a significant increase in the maximal voluntary ventilation (p<.05). There was no significant difference in variation of the maximal voluntary ventilation between the two groups (p>.05). Conclusion : As a results of this study, PFME using a smartphone application seems to induce voluntary participation of subjects and maintain continuity against time constraints. As a result, it is thought that using a smartphone application when performing PFME is efficient and convenient in terms of research method. However, this study is difficult to generalize due to the small number of subjects and short intervention period. Therefore, additional research should be conducted by modifying and supplementing these limitations.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.6
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• pp.749-762
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• 2019

In recent years, in urban areas, underground of roads are being promoted in order to resolve traffic congestion and to secure green spaces, and due to the low ratio of large vehicles, they are planned or constructed as road tunnels for small cars only. In addition, the tunnels being built in the city is a tendency to be enlarged to play the role of main roads. Accordingly, the capacity of the ventilation system is increasing and various ventilation methods are required, and the importance of maintenance after the completion of the tunnel such as the operating cost of the ventilation system is emphasized. Therefore, the need for optimization of the operation stage for reducing the power consumption of the ventilation system and the study of the ventilation system operation control logic is increasing. In this study, the study on the necessity of the optimization of operation stage and control logic of the ventilation system was carried out to realize the energy-saving operation for the small car only passing through tunnels which is applied of ① jet fan and combination ventilation system (② jet fan + air purifying equipment, ③ jet fan + vertical shaft, ④ jet fan + supply air semi-transverse). As a result of this study, there can be various operating combinations in the case of the combined ventilation system, and even though the amount of ventilation air is the same, the operating power varies greatly according to the operating combinations. It was found that operating the axial fan first rather than the jet fan first operation method has an effect on power saving.

• Fire Science and Engineering
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• v.24 no.1
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• pp.90-94
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• 2010

In this study it is intended to review the moving characteristics of smoke by performing visualization simulation for the calculation of the optimal smoke exhaust air volume in case a fire occurs in tunnels where transverse ventilation is applied, and to obtain basic data necessary for the design of smoke exhaust systems by deriving optimal smoke exhaust operational conditions under various conditions. As a result of this study, if it was assumed 0 critical velocity in the tunnel, the smoke exhaust air volume was limited within 250 meter in the road-tunnel disaster prevention indicator and the exhaust efficiency was from 55.1% to 95.8% in the result of this study. If the wind velocity is in the tunnel, the exhaust rate intends to increase rapidly and the exhaust efficiency is decreased. In addition, if the wind velocity is increased, the exhaust rate should be increased in compared with the generation rate of smoke in maximum 1.8 or 1.04 times. In this study, when the wind velocity is in the tunnel, the limited exhaust rate is $84m^3/s{\cdot}250m$. And if it was assumed 1.75 m/s critical velocity in the tunnel, the exhaust rate would be defined $393m^3/s{\cdot}250m$($Q_E$ = 80 + 5Ar).

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2007.11a
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• pp.375-380
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• 2007

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.4A
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• pp.245-253
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• 2012

In the longway tunnel and underground traffic road, the structure of transverse ventilation system is constructed by the airpit slab. In this study, the full scale specimens of the PSC airpit slab that attached fire resistance panel are performed the static and dynamic loading tests for evaluation of bending capacity. The first of all, it confirmed the evaluations about the fundamental efficiency of the fire resistance panel and PSC slab by the 3-point bending test and pull-off test. The tests are performed for evaluation of the bending resistance under ultimate static load and the bonded capacity under dynamic fatigue load. A fatigue test is performed for an investigation of the effect on wind pressure that is developed by transit of traffic. The damage or debonding on surface between fire resistance panel and PSC slab was not developed in dynamic fatigue load test, also the behavior of the specimens is very stable and the debonding of the fire resistance panel attached at the bottom surface of PSC slab was not developed in static load test, too. Therefore, the crack or debonding of the fire resistance panel will be not developed by external loads during the construction or completion of the precast fire resistance system.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.6
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• pp.887-895
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• 2019

Recently, the number of underground road development projects has been increasing to solve traffic problems in the national capital region and metropolitan areas with intensified overcrowding, and there has been a tendency to plan underground roads by applying a double-deck tunnel technology that has advantages in constructability and economical efficiency. The double-deck tunnel has a structure where one excavation section is divided into two parts and used as up and down lines, and is mainly used as a road for small vehicles only due to its low floor height. In addition, due to the small cross-sectional area, it has characteristics different from those of general road tunnels in terms of ventilation and disaster prevention. In this regard, this study proposed an operational plan that applies an oversized exhaust system, which is one of semi-transverse ventilation systems, to small cross-sectional tunnels like double-deck tunnel with low floor height, and a comparative analysis between smoke exhaust characteristics according to the fire occurrence locations and oversized exhaust systems was conducted using the Fire Dynamics Simulator (FDS). The results showed that unlike uniform exhaust, intensive smoke exhaust using the oversized exhaust port maximized the delay effect of smoke diffusion and limited the smoke within 50 m above and below the fire point.

• Journal of The Korean Society of Integrative Medicine
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• v.10 no.1
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• pp.81-89
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• 2022

Purpose : Kegel exercises reported that it is effective in managing stress-related or complex urinary incontinence through contraction and relaxation of the pelvic floor muscles. In many previous studies, it was confirmed that Kegel exercise is involved in respiration as well as urinary system diseases. However, there is a lack of research on the effect of pelvic setting when performing Kegel exercises. Therefore, this study was conducted to investigate the effect on maximum voluntary ventilation (MVV) and abdominal muscle thickness through Kegel exercise after lumbar-pelvic motor control using pressure biofeedback unit (PBU). Methods : The subjects of this study were 10 healthy female students in their 20s. Subjects measured MVV with a spirometer. In hooklying, external oblique, internal oblique, and transverse abdominis of the dominant hand were measured using ultrasound. The measured value was an average of three times. After one week of intervention, measurements were made in the same manner. Before Kegel exercise, pelvic setting training was performed using PBU. In hooklying, PBU was placed in the waist and set to 40 mmHg, and it was adjusted to 60 mmHg through pelvic muscle contraction. For Kegel exercise, the pelvis was first set using PBU, and then the pelvic floor muscles were contracted for 8 seconds and relaxed for 8 seconds, 10 times, 1 set, and 3 sets. Results : In MVV, a significant difference was confirmed after exercise than before exercise (p<.05). There was also a significant difference in abdominal muscle thickness before and after exercise (p<.05). Conclusion : Based on the results of this study, Kegel exercise using PBU had an effect on MVV and abdominal muscle thickness. However, since this study was conducted without a control group as a preliminary study, additional research should be conducted to supplement this.

• International Journal of Safety
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• v.4 no.2
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• pp.30-35
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• 2005

In case of tunnel fire, one of the most effective facilities to save lives is the smoke control system. In this study, two different smoke extraction schemes of transversely ventilated tunnel were compared. One is the smoke extraction using the fixed exhaust ports on the false ceiling to achieve the uniform and distributed smoke extraction (uniform exhaust). The other is that using the remote controlled smoke extraction where only vents close to the fire is opened whereas the others are closed to enhance the limitation of the smoke spread (localized exhaust). A number of numerical simulations were performed to find out the optimal smoke extraction rate at each smoke extraction scheme to allow the tunnel users to escape to the safe area without endangering their lives by smoke.

• Particle and aerosol research
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• v.8 no.1
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• pp.17-28
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• 2012

Air pollution levels of gases and aerosol particles inside the Jeongneung and Hongjimun tunnels of the Naebu express way in Seoul were investigated through on-road measurement using a mobile emission laboratory (MEL) on February 8, 2011. The concentrations of $NO_x$, $CO_2$, number concentration of particles ranging 21-560 nm, and surface area of particles deposited on a human lung almost linearly increased with increasing distance from the tunnel entrance, and decreased rapidly before the tunnel exit. This trend was observed regardless of tunnel length and driving directions, which thought to be caused by semi-transverse ventilation facilities of the tunnels. The concentration increments per 1-m distance for $NO_x$, $CO_2$, deposited particle surface area, and number of particles ranging 21-560 nm were 0.61~0.80 ppb, 0.16~0.21 ppm, $0.20{\sim}0.29{\mu}m^2/cm^3$, and 117~192 particles/$cm^3$, respectively. Average pollution levels inside the two tunnels for $CO_2$, deposited particle surface area, and number of particles >5.6 nm ranged 681~748 ppm, $246{\sim}381{\mu}m^2/cm^3$, and $2.4{\sim}6.7{\times}10^5$ particles/$cm^3$, respectively. In case of $NO_x$, the maximum concentration exceeded 1 ppm. These pollution levels inside the tunnels are much higher than those at urban background sites. This result can be utilized as basic data to evaluate the effectiveness of present ventilation system for reducing the pollution level caused by vehicles inside the tunnels.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.5
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• pp.359-370
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• 2021

Duct slabs, which are used to build ventilation facilities in underground spaces with transverse ventilation system, need to secure fire resistance according to longitudinal and heavy vehicle traffic of tunnels. This study measured the temperature change at the construction joint of the precast fireproof duct slab which integrates fire resistance material and duct slab under the RWS fire scenario. As a result, it was confirmed that if there is no reinforcement of the construction joint, damage will occur in concrete inside the construction joint, leading to damage to the fireproofing layer. On the other hand, when one side of the construction joint was reinforced with fireproofing materials, it showed more than three times the fire resistance performance compared to when there was no reinforcement. At this time, cross-sectional losses of concrete and fireproofing layer were shown in blocks without reinforcement, but no damage was seen in the reinforced blocks.