• The Journal of the Acoustical Society of Korea
• /
• v.28 no.1E
• /
• pp.9-15
• /
• 2009

In this paper, FSTL (Field Sound Transmission Loss) measured in a mock-up simulating ship cabins is studied. A mock-up is built by using 6 mm steel plate, and two identical cabins are made where 25 mm or 50 mm sandwich panel is used to construct wall and ceiling inside the steel structure. Various wall panels and ceilings are tested, where effects of wall and ceiling panel thickness, and presence of a unit toilet on FSTL are investigated. It is found that the effect of unit toilet on FSTL is at most 1 dB. From the comparison of FSTL for panels of the same thickness of 50 mm, it is observed that panel having inside air cavity of 10 mm shows higher STL than that of the panel without air cavity. Comparison of FSTL for panels of 50 mm and 25 mm thickness shows that dependency on surface density predicted by mass law is not observed. The sandwich panels act as a mass-spring system, which shows a resonant mode that cannot be explained by the mass law. It is also found that STL from laboratory test is higher than FSTL by 5- 10 dB, which can be explained by flanking structure-borne noise transmission path such as ceiling, floor and corridor-facing wall.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 2008.04a
• /
• pp.117-119
• /
• 2008

It is very important to protect life, property at sea from any fire. Recommendation on improved fire test procedures for surface flammability of bulkhead, ceiling and deck finish materials specifies a procedure for measuring fire characterizing their flammability and thus their suitability for use in marine construction. In this paper, we investigated the positive expected by fire test procedures for flammability of bulkhead, ceiling and deck finish materials. Also, unusual materials were analyzed. Finally, we suggest methods to solve several problems related to unusual materials.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.50 no.1
• /
• pp.39-47
• /
• 2008

Most of the broiler houses in Korea have experienced problems on controlling the environmental conditions such as suitability, stability and uniformity of rearing condition inside the broiler house. It is very critical which if not properly controlled, would cause serious stress on the chickens. It is therefore urgent to develop optimum designs of naturally ventilated broiler house which is appropriate to the four seasons of Korea. Field experiment for this matter is very difficult to conduct due to the unpredictable and uncontrollable weather condition. In this study, the heating load of a naturally ventilated broiler house was calculated using TRANSYS 15 BES program while internal climate and thermal condition were computed using Fluent 6.2. The computed resulted of the conventional ventilation system (A) and upgraded ventilation system (B) (Seo et al, 2007) were compared with each other for cold season. The results of the Building Energy Simulation(BES) indicated that the system B, the upgraded ventilation system made 8% lower total heating load and 47% lower at only the broiler zone compared to the conventional broiler house. Considering the entire broiler house, the existence of middle ceiling made the heating energy 11% lower required than without middle ceiling. Accordingly, the system B with middle ceiling was found to save heating energy by 20% in average. This study showed that the BES program can be a very powerful to effectively compute the energy loads of agricultural building while the energy load is very close related to ventilation efficiency.

• Journal of Korean Society of Disaster and Security
• /
• v.13 no.1
• /
• pp.51-58
• /
• 2020

This paper analyzes the effect of airflow of ceiling air conditioner on the operation of sprinkler head using a simulation program. The simulation space is 10 m × 7 m × 3 m, and the size of the fire is 0.8 m × 0.8 m × 0.6 m. The cold air flow from the air conditioner is at 25℃ and the wind speed is divided into three cases : 10 ㎧, 8.5 ㎧, and 7.5 ㎧. Simulation results show that all cases had operating delays compared to when the air conditioner was not running, and the sprinkler head did not operate until 10 minutes had elapsed at 10 ㎧ wind speed. These results confirmed that the sprinkler head was delayed in the air conditioning space and the worst result of early evolution failure was observed in strong winds such as 10 ㎧.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.46 no.2
• /
• pp.75-83
• /
• 2009

This paper presents a new mobile robot localization method for indoor robot navigation. The method uses color-coded landmarks on the ceiling and a camera is installed on the robot facing the ceiling. The proposed "cell-coded map", with the use of only nine different kinds of color-coded landmarks distributed in a particular way, helps reduce the complexity of the landmark structure. This technique is applicable for navigation in an unlimited size of indoor space. The structure of the landmarks and the recognition method are introduced. And 2 rigid rules are also used to ensure the correctness of the recognition. Experimental results prove that the method is useful.

• Fire Science and Engineering
• /
• v.24 no.1
• /
• pp.95-102
• /
• 2010

The combustion characteristics of roof 'Jucsim' structure was analysed using real scale fire test on wooden structure heritage building. the fire test model was made to consider roof timberling internal structure for a Sunglemun. Structure of test body layed lime, soil, 'Jucsin' and ceiling board excepting roof tile to find heat propagation process by setting thermocouples. The first test to find fire growth and heat propagation process in the part of ceiling. The second test organized to find the efficiency of fire proof paint between ceiling board and inside of Jucsim structure. The third test try to get the performance level of fire proof fabric with the same manner. The result showed from the test proof the heavy smoke exposure with limited effect of fire proof paint however, reliable fire resistance effect showed in case of fire proof fabric.

• Journal of KIISE:Computer Systems and Theory
• /
• v.28 no.11
• /
• pp.573-580
• /
• 2001

When tasks access shared resources in real-time systems, the unbounded priority inversion may occur. In such cases it is impossible to guarantee the schedulability of real-time tasks. Several resource access protocols have been proposed to bound the duration of priority inversion and sufficient conditions are given to guarantee the schedulability of periodic task set. In this paper, we show an improved sufficient condition for schedulability when the dynamic priority ceiling protocol is used. Our approach exploits the fact that a lower priority task can continue to execute as far as the higher priority tasks do not miss their deadlines. This permitting execution time of the higher priority tasks for a lower priority task can be excluded from the worst-case blocking time of the higher priority tasks. Since the worst-case blocking time of tasks can be reduced, the sufficient condition for schedulability of dynamic priority ceiling protocol becomes further tight.

• Korean Journal of Heritage: History & Science
• /
• v.48 no.4
• /
• pp.44-61
• /
• 2015

Mural tomb in Goa-ri(Goryeong) built in the 6th Century Gaya period investigated precisely by the scientific method. They were used to optical equipments for investigation and made a damage map according to the damaging types. The mortar layer was mostly exfoliated from the rest of the wall except for the burial chamber ceiling and corridor ceiling. Also painting layers rarely not observed. Most of the paintings were damaged except lotus painting in burial chamber ceiling. Various damage types that exfoliation, earthen dirt, film coating were found in murals. Damage factors of mural were the porous characteristics of mortar layer and the movement of moisture in the murals. They were caused physical damage such as crack, exfoliation. It was getting worse and causing to secondary damage like earthen dirt, film coating.

• Industry Promotion Research
• /
• v.4 no.1
• /
• pp.1-9
• /
• 2019

This study is a technology related to a seismic protection device for a fire pipe for installation in a building such as an apartment or a building. The fire pipe is fixed to the base panel by fastening bolts so as to flow left and right. The present invention relates to an earthquake-resistant apparatus for a fire-extinguishing piping, which is capable of minimizing damages caused by an earthquake in order to prevent damages and breakage of a fire-extinguishing pipe by mitigating earthquakes, vibrations, It is connected to an insert plate embedded in concrete or ceiling hanger bolts formed at regular intervals on the ceiling to keep the piping constant from the ceiling and to keep the horizontal condition of the piping always constant so that the piping relaxes or sags And to effectively prevent damage to the piping. The can get.

• Journal of the Society of Disaster Information
• /
• v.15 no.1
• /
• pp.98-108
• /
• 2019

Purpose: The purpose of this study is to test the sprinkler performance to protect the wall and ceiling joints of the sandwich panel warehouse in case of fire. Method: Based on the field surveys, test was setup and combustibles were prepared. The sprinkler discharge tests were performed at the corner of the wall and right under the sprinkler head. Results: It has been found that operation of the K-80 closed sprinkler head prevents the ignition of the sandwich panel and therefore no damage to the joints of sandwich panels. To prevent skipping phenomenon, it is necessary to install the sprinkler head from the corner of the wall and to keep a minimum distance of 2.4m and a maximum distance of 3m. Conclution: A Standard Operation Procedure should be prepared to suppress and rescue of fire brigade for a sandwich panel warehouse protected by perimeter sprinklers preventing a ignition of core materials and control fire.