• Fire Science and Engineering
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• v.25 no.2
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• pp.101-106
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• 2011

In case of an emergency such as a fire on a building and there is a need to evacuate the occupant in that building, it is important to have the guidance information effectively delivered to the evacuating occupants to guide them toward a safe direction using audio sensual media. And, it is also very important to prevent the evacuating occupants getting lost or falling astray, away from the direction toward safety. The purpose of this study, in this respect, is to examine the possible application of the precedent sound effect, with which the evacuating occupants may get a sense of the direction where the announcement comes from. With such an effect, an experiment was conducted to measure the extent to which people can hear the preceding and the following sound in terms of the acoustic pressure level changes and delay time changes, with a view to make the optimal evacuation-guidance announcement or sound. The optimal evacuation guidance sound (announcement) per each of the experimental indoors environments were as follows; 1) Regarding the optimal condition for the evacuation guidance announcement sound in the space of a lecture room, the direction of the advanced sound is positively recognized when the follow-up sound has the delaying time of 10 ms~50 ms in comparison with the advanced sound or when there is no difference between the acoustic pressures of the advanced and follow-up sounds or the acoustic pressure of the advanced sound is higher than that of the follow-up sound. 2) Regarding the optimal evacuation guidance announcement sound in the space of a hall, the advanced sound is positively recognized when the follow-up sound has the delaying time of 20 ms~60 ms in comparison with the advanced sound. 3) Regarding the optimal evacuation guidance announcement sound in the space of a gymnasium, the advanced sound is positively recognized when the follow-up sound has the delaying time of 10 ms~40 ms in comparison with the advanced sound or when the sound pressure of the advanced sound has a higher level than or the same level as that of the follow-up sound.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.5
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• pp.23-29
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• 2023

The goal of this study is to evaluate the bursting characteristics and fire resistance performance of mixed cement concrete containing fibers at very high temperatures. For this purpose, FA-based, Slag-based, and each mix according to the amount of fiber mixed were heated to room temperature, 150℃, 300℃, 600℃, and 900℃, and then the burst shape, compressive strength, and elastic modulus were measured and evaluated. As a result of the experiment, it was found that relatively more surface damage occurred in FA-based specimens when heated at ultra-high temperatures than in slag-based specimens, and there was a difference between the mix without fibers and the mix with fibers when heated at ultra-high temperatures, that is, at 900℃. In the mix without fibers, a decrease in strength of more than 5% occurred. In addition, the elastic modulus also showed the same phenomenon as the compressive strength, and in particular, the decrease in elastic modulus was found to be greater than the amount of decrease in compressive strength. Meanwhile, estimation equations for compressive strength and elastic modulus according to heating temperature were statistically proposed.

• Applied Chemistry for Engineering
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• v.18 no.3
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• pp.251-254
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• 2007

Veneer plate was painted by the treatment with ammonium salts such as ammonium chloride (AMCR), ammonium sulfate (AMSF), monoammonium phosphate (MAPP), and diammonium phosphate (DAPP) at room temperature. The flame retardancy of painted veneer plate was investigated. The painted veneer plate shows an increased $CO/CO_2$ over virgin veneer and it was supposed to affect the toxicity to different extents. But when the ammonium salts were used as the retardant for veneer, the flame retardancy was improved due to the painted ammonium salts in the veneers. Also, the veneer plates with ammonium sulfate and ammonium chloride showed both the lower total smoke release (TSR) and lower total smoke production (TSP) than that of virgin veneer.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.6
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• pp.375-378
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• 2015

In this study, in order to develop the composition ceramics with the excellent electrocaloric properties, $(Pb_{0.88}La_{0.08})(Zr_{0.65}Ti_{0.35})O_3$ ceramics were fabricated by the conventional solid-state method. Electrocaloric effects of $(Pb_{0.88}La_{0.08})(Zr_{0.65}Ti_{0.35})O_3$ ferroelectric ceramics were investigated and discussed using the characteristics of P-E hysteresis loops at wide temperature range from room temperature to $220^{\circ}C$. The temperature change ${\Delta}T$ due to the electrocaloric effect was calculated by Maxwell's relations, and reached the maximum of ~0.19 at $190^{\circ}C$ under applied electric field of 30 kV/cm.

• Journal of the Korean housing association
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• v.23 no.6
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• pp.21-30
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• 2012

In foreign countries, the use of containers has already been stabilized with their advantages utilized in various forms. Containers are also utilized in Korea as various forms of architecture, but domestic container buildings have poor public consciousness so as to be limitedly utilized as temporary structures based on economic efficiency. Besides, there is the lack of research and development on them. Particularly, despite the advantages of containers as housing facilities, the use of containers as short- or middle-term temporary housing is limited and does not spread. Also, compared to general housing, containers have lower quality of physical environment and even frequently bring about negligent accidents such as fire and electric shock. Thus, this study intends to identify the actual condition of using container houses, the problems in using them, and the direction of improving their residential environment. For this purpose, it analyzes the present condition and characteristics of domestic container housing, and derives conclusions from the focus group interview with 23 residents who have lived in Seoul and Gyeonggi-do for over a year about such survey items as daylighting, ventilation, privacy condition, water service and sewerage, insulation, soundproofing, view, and room scale.

• Journal of the Korean Institute of Rural Architecture
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• v.14 no.4
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• pp.11-18
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• 2012

This study is to establish the dwelling principle and architectural characteristics of Powhatan Indian Community in Eastern part of North America. To find a pattern and dwelling principle of town building and housing, I have researched both site survey of Powhatan at Jamestown Settlement in Virginia and a related references of North America Indian. In addition of study, I have tried to understand their life style in 17C, a spatial characteristics of space composition, and a using materials of Yehakin which means Powhatan's house in the exhibition hall of Jamestown Settlement. The results of this paper are as follows: First, the form of Powhatan house is like a longhouse which has two types that are oblong and rectangular house. Usually they had lived in the style of oblong house. Second, there are three patterns to set up the semi-permanent settlement of Powhatan, which are circle-type, street-type, and free-type of village. Third, the fire place of interior space that is most importance element to heat and cook is put it into the center of room, and the other beds and shelves are arranged by the side of wall which is covered of rush matt.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.27 no.1
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• pp.5-13
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• 2017

Noise complaints among neighbors in apartment building are mainly caused by floor impact noise that is structure born noise due to occupant induced floor vibration. To control this noise problems many researchers have investigated floor systems and finishing materials. Light-weight impact noise affects by finishing materials, but heavy-weight impact noise induced by heel impacts during normal walking or jumping of children is concerned with structural system and floor vibration. To figure out the characteristics of floor impact noise and transmission of floor vibration due to human activities, vibration tests were conducted in apartment buildings. Impact hammer, heel drop and walking activities were loaded at center of upstairs living room, and accelerations of slabs for both upstairs and downstairs and sound pressure levels for downstairs were measured. The acceleration ratio of transmitted floor vibration to downstairs and human induced vibration in upstairs was between 0.5 and 1.0 according to slab size, wall, and load type. And floor impact noise occurred in the range of natural frequency of slab.

• Design & Manufacturing
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• v.14 no.2
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• pp.28-33
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• 2020

Recently, as the income level and quality of life have improved, the desire for a pleasant environment has increased, and a deodorization plan is required through thorough prevention and diffusion of odorous substances in waste treatment facilities recognized as hateful facilities, appropriate collection, and selection of the right prevention facilities. In this study, a waste disposal facility was modeled and computerized analysis for odor and ventilation analysis was conducted. Numerical analysis of the waste treatment facility was performed at the size of the actual plant. CATIA V5 R16 for numerical model generation and ANSYS FLUENT V.13 for general purpose flow analysis were used as analysis tools. The average air-age of the internal was 329 seconds, and the air-flow velocity was 0.384m/s. The odor diffusion analysis inside the underground pump room showed congestion-free air circulation through streamline distribution and air-age distribution. This satisfies the ASHRAE criteria. In addition, the results of diffusion analysis of odorous substances such as ammonia, hydrogen sulfide, methyl mercaptan and dimethyl sulfide were all expected to satisfy the regulatory standards. Particularly in the case of the waste loading area, the air-flow velocity was 0.297m/s, and the result of meeting the regulatory standards with 0.167ppm of ammonia, 0.00548ppm of hydrogen sulfide, 0.003ppm of methyl mercaptan, and 0.003ppm of dimethyl sulfide was found.

• Korean Journal of Computational Design and Engineering
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• v.19 no.2
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• pp.169-181
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• 2014

Recently ships and ocean platforms are becoming increasingly technological, unmanned, and huge. Maintenance and safety monitoring of these products is very important for safety reasons. Therefore, real-time monitoring of safety regions, such as the engine room, and hull structure, and environmental states, like fire and pressure of LNG tanks, is required for the sustainable ships. In this paper, a ZigBee-based wireless sensor network is suggested to monitor ships and ocean platforms effectively. However, this causes some telecommunication problems because these products are made of steel. To resolve this problem, we use the mesh networking of Zig-Bee that can monitor the regions and environmental states consistently. The telecommunication of such a monitoring system is tested on a real container ship and its performance is verified. The real-time monitoring results are displayed on the users' smart devices.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.246-249
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• 2009

Test and launch facilities which use oxygen as the propellant of a launch vehicle have hazards of fire and explosion by the leakage of oxygen. Also, the personnel operating the facilities, which use the high-pressured gases like nitrogen and helium in the closed room, is exposed to the hazard of death from suffocation. Consequently, we should keep out of the hazards and the accidents by monitoring the contents of oxygen in the air. The method and the system construction for monitoring oxygen contents in the air and the results from its application to Naro space center are described on this paper.