• Proceedings of the KSR Conference
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• 2004.06a
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• pp.927-934
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• 2004

For the purpose of speed-up of conventional lines with many curves, the introduction and operation of tilting train is under process. Those are Joong-Ang, Jang-Hang and Ho-nam lines etc. Tilting trains can run a curve section faster than existing trains without a significant violation of passenger's comfort and enable to reduce operating time in the lines with many curves. In this study, the trains speeds are evaluated, based on the alignment of conventional line, criteria for passenger's comfort and investigated field conditions of the sections where the curves exist. Decision on whether the alignment(transition line) needs to be modified or not is also made. Relative efficiency on curve sections of tilting train to existing trains is approximately $50\%$ in average.

• Journal of the Korean Society for Railway
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• v.14 no.6
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• pp.545-554
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• 2011

In order to get dynamic serviceability of a train travelling on a railway bridge, comfort limits with the deflection of bridge and vertical acceleration on car body are proposed in Eurocode, Shinkansen design criteria, The design guideline of the Honam High-speed railway. The design guideline of the Honam High-speed railway has quoted Eurocode. Therefore it is expected that supplementation of comfort limit of railway bridge according to expansion of span length and the improvement traveling speed of trains in the future would relatively fall behind developed countries in railway. Therefore, in order to secure technological competitiveness in world market, the study was conducted to propose the deflection limit based on vibration serviceability of railway bridges that can consider bridge-train interaction and travelling speed increase. The parameter study and bridge-train dynamic interaction analysis was conducted to figure out the correlation of vertical acceleration on car body and bridge displacement according to the increase in travelling speed. Also, the trend of increasing vertical acceleration on car body according to the increase in travelling speed was confirmed, and the amplification coefficient of vertical acceleration on car body was suggested. And the deflection form and vibration of the bridge were assumed to be in harmonic motion, and transfer function and the amplification coefficient were used to develop the dynamic serviceability deflection limit of the high-speed railway bridge as a formula.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.7
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• pp.527-533
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• 2002

A railway vehicle should be satisfied with the safety criteria and ride comfort of passengers. A bogie of railway vehicle Is composed of many suspension components, such as springs, dampers and etc.. that have an influence on the dynamic behavior of the train wish the wheel/rail profiles and track geometries. Therefore, it Is necessary for engineers to check the Interference between vehicle limit and construction limit with considering the vehicle's behavior, because when the vehicle is running on curved track, it should be have enough clearance from infrastructure for safely, spacially In a subway system. This paper explains the effective method of analysis for vehicle limit considering the vehicle dynamic behavior and reviews the problem of vehicle limit for the Korean Standard Urban Train. The results show that the vehicle limit is over the construction limit when the Korean Standard Urban Train runs on the curved track with 180 m radius of curve.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.4
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• pp.307-312
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• 2007

This study was performed to evaluate sleep efficiencies and conditions for comfortable sleep based on the analysis of sleep efficiency and MST under four thermals conditions ($22^{\circ}C,\;24^{\circ}C,\;26^{\circ}C,\;30^{\circ}C$). Five female subjects who have similar life cycle and sleep patterns were participated for the sleep experiment. Their age was from 20 to 22 years old. They were healthy, and had regular sleep with consistent bed and wakeup time. It was checked whether they had a good sleep before the night of experiment. Experiments were performed in an environmental chamber using thermo-hygrostat. The physiological signal (EEG) for sleep stage were obtained from C3-A2 and C4-Al electrode sites. Sleep stages were classified, then SWS latency and SWS/TST were calculated for the evaluation for sleep efficiencies on thermal conditions. As results, mean skin temperature for comfort sleeping was $34.5{\sim}35.4^{\circ}C$. Considering sleep efficiency and mean skin temperature, indoor room temperature of upper limit was $28.1^{\circ}C$.

• Tunnel and Underground Space
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• v.7 no.4
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• pp.310-322
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• 1997

New limits of comfort boundary, psychological damage boundary and exposure limit for building residents by continuous and vibration are suggested. These limits are derived from the ISO 2631 and DIN 4150 regulations. A reasonable method to evaluate damages by vibrations is also suggested using the "total over-exposure of vibration" concept.; concept.

• Journal of Environmental Science International
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• v.27 no.12
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• pp.1261-1269
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• 2018

The purpose of this study was to investigate changes in the external thermal environment, following the application of evaporative cooling systems in buildings, in response to climate change. In order to verify changes in the external thermal environment, a T-test was performed on the microclimate, Thermal Comfort Index (TCI), and building surface temperature. Differences in microclimate, following the application of the evaporative cooling system in the building, were significant in terms of temperature and relative humidity. In particular, temperature decreased by more than 7% when the evaporative cooling system was applied. According to the results of the Thermal Comfort Index analysis, the Wet-Bulb Globe Temperature (WBGT) was below the limit of outdoor activities, indicating that outdoor activities were possible. The Universal Thermal Climate Index (UTCI) values were within the very strong heat stress range when the evaporative cooling system was not applied, When the system was applied, the UTCI values were within the strong heat stress range, indicating that they were lowered by one level. The building surface temperature decreased by ~10% or more when the evaporative cooling system was applied, compared to when it was not applied. Finally, the outside surface temperature of the building decreased by ~12% or more when the system was applied, compared to when it was not applied. We conclude that the energy saving effect of the building was significant.

• Journal of the Korean Solar Energy Society
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• v.31 no.6
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• pp.78-85
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• 2011

In this study, an underfloor air distribution(UFAD) system installed on the S. office building was evaluated for its indoor environmental quality performance. Field measurement and survey were conducted for the overall POE(Post Occupied Evaluation). PMV(including temperature, humidity, air velocity and globe temperature) and several environmental components were measured while thermal comfort, thermal sensation, acoustical environment and others. were investigated through survey. Except for the direct upper part of the air supply diffuser on the floor, the indoor velocity was less than 0.25m/s, which has been suggested by ASHRAES tandard 55 as the limit for thermal comfort. MRT of the perimeter zone of the room showed a higher value than that in the interior because of the introduced solar radiation through the building envelope. PMV was generally maintained in the range of thermal comfort (from -0.5 to +0.5), though it weighted to the warm side. It was reported to have 61% positive response on thermal comfort and 55% on neutral thermal sensation. The results of each survey item showed some gender-based differences. Specifically, female respondents had higher degree of dissatisfaction with indoor air cleanness and acoustical privacy. The working surface showed more than 400 lux and the equivalent noise level showed less than 50 dB(A). In conclusion, the results of the measurement and survey showed good agreement. Indoor environmental quality of the subject office room where the UFAD system was installed showed an overall excellent performance.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.24 no.4
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• pp.15-29
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• 2021

Urban green spaces offer a variety of benefits to living things and humans. However, existing green spaces have been reduced and fragmented due to urbanization, and there is a limit to creating new large green spaces in densely developed cities. Street trees have fewer restrictions on land use, which can be a measure to secure green areas in cities. In Korea, excessive pruning is being done on some street trees for reasons such as blocking of building signboards, contact with electric wires, and restrictions on sidewalk widths. Therefore, it is necessary to quantitatively understand the relationship between the benefits provided by street trees and their structures to come up with an efficient and systematic planning and management plan for urban street trees. In this study, we quantitatively analyzed the relationship between the thermal comfort improvement by the shades of street trees and the vertical structure, planting environment, and types of street trees. To calculate the thermal comfort felt by human body, we calculated UTCI (Universal Thermal Climate Index) of each street tree. For the vertical structure of street trees, we used Terrestrial LiDAR and the point clouds of street tree's crown was sliced vertically at 1m intervals. We conducted a multiple regression analysis on the thermal comfort improvement using the variables we obtained from fields. As a result, in the case of a street tree's vertical structure, the lager the volume of tree's crown located 3-4m (β=0.298, p<.05) and 6-7m (β=0.568, p<.001) above clear length, the better the cooling effect. In addition, the thermal comfort improvement was assessed to decrease as the DBH increased (β=-0.435, p<.001). In general, the crown diameter and DBH are positively correlated, with a cooling effect occurring as crown diameter increases. In this study, the opposite result was obtained due to the small number of trees measured, so additional research is needed by increasing the number of tree samples. In the case of the planting environment, the effect of improving thermal comfort was higher in the shaded area of trees planted to the south (β=-0.541, p<.001). Since unsystematic management of street trees can deteriorate the function of them, quantitative evaluations of the vertical structure of street trees are required, which can provide specific measures for planning and management of urban street trees with thermal comfort effect.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1811-1814
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• 2007

Accommodation error is one of the main factors that degrade the comfort while watching stereoscopic 3D images. We analyze the limit of the expressible 3D depth without an accommodation error using the human factor information and wave optical calculation under Fresnel approximation.

• International Journal of High-Rise Buildings
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• v.10 no.3
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• pp.165-171
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• 2021

Core-outrigger-mega frame system is used in Suzhou IFS with 95-story, 450 m-tall, which is beyond Chinese code limit. Besides simple introduction on design principle, structure system and analysis, key techniques including performance based design criteria, frame shear ratio, capacity check of mega column, human comfort criteria under wind induced vibration and TSD design were presented in details for reference of similar super tall building design.