• Journal of Biosystems Engineering
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• v.20 no.2
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• pp.127-132
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• 1995

In the first part of this paper, an analysis of the cab noise of a selected agricultural tractor was presented. In this study, using the results of the previous analysis, two passive noise control measures of the sound insulation and absorption were conducted to reduce the noise level inside the cab. These measures of noise control reduced the total noise level by 6.2㏈(A) at the operator position inside the cab. In order to further reduce the cab noise, particularly, of lower frequencies than 630Hz, stiffness and damping of the floor panel should be enforced. It was also suggested that a proper suspension for the cab mounting is necessary to reduce the level of structure-born noises.

• Journal of the Korean Society of Safety
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• v.6 no.1
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• pp.14-25
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• 1991

The smouldering combustibility of cellulose insulation treated with boric acid-borax-alum as combustion retardants are examined by cigarette ignition method and electrical cardrige heater method. The alum to be required at an add on level of at least 12% by weight of cellulose treated with boric acid-borax-alum=2 ： 1 ： 2 fomulatlon if resistance to smouldering combustion by cigarette ignition is to be achived. The optimum electrical ignition source employed by electrical cartidge heater method was 23.2 watts(80V) power level The effectiveness of Alum as a third combstion retardant are acceptable both smouldering resistance and flame resistance at 18% level of all examined formulation.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.5
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• pp.639-646
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• 2017

This paper describes the sound insulation and structural safety of the shelter which may be used for shooters. The noise level of the shelter should be less than 100 dB on the basis of the Industrial Safety and Act, the World Health Organization and the MIL-STD. The sound insulation design was designed for the shelter structure. The designed shelter performance was verified by the real measurement after completing the construction of the shelter. The system was also designed using the finite element method with data of sound pressure measured in the test. Its response was obtained numerically. It is proved that the shelter structure is sufficiently safe considering the calculated maximum stress level with the allowable stress of structural property.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.522-529
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• 2005

The commercial service of KTX from April 1st 2004 has realized that whole country has shrunk into half-day life zone and it opened the times of speed. However, some technical problems unexpected before service have been raised and, among them, the noise generation at train passing was claimed by the residents living nearby the track and it is often publicized by the broadcastings and newspapers. In case where the residential area is close to the track, the installation of noise barrier at trackside is the general measures for noise reduction on bridge section and earthwork section. In case of KTX project, such measures were actually taken without any exception; however, the noise level is still high. In this study, analysis for the reason of higher noise level in spite of which the noise barriers are being installed was carried out, the sample of insulation material effective for noise barrier was manufactured and the performance of the insulation material was evaluated to verify its effectiveness

• KEPCO Journal on Electric Power and Energy
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• v.6 no.2
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• pp.119-122
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• 2020

With recent ESS (Energy Storage System) fire accident, the fault protection performance is becoming more important. However, there has never been any experiments with the protection performance on the faults in the ESS system level. In this study, the effect of AC ground fault and IGBT (Insulated Gate Bipolar mode Transistor) short-circuit failure on MW class ESS was performed experimentally for the first time in the world. First of all, the effect of the AC single line ground fault on battery was analyzed. Moreover, the transient voltage was investigated as a function of the battery capacity and the power level. Finally, the breaking capability and insulation performance of ESS were examined under PCS short-circuit fault condition. Through the tests, it was found that ESS protection system safely blocked the faulty current regardless of the faults, whereas the electronic parts such as IGBT and MC (Magnetic Contactor) were broken by the fault current. Also, the electrical breakdown in ESS resulted from the transient voltage during the protection process.

• Journal of Electrical Engineering and Technology
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• v.13 no.3
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• pp.1346-1354
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• 2018

Quality of the power system depends upon the reliability of its components such as transformer, transmission lines, insulators, circuit breakers and isolators. The transient voltage due to internal or external reasons may affect the insulation level of the components. The insulation level of these components must be tested against these conditions. Different studies, testing of different electrical components against high voltage impulses and different industrial applications rely on the international manufactures for pulsed power generation and testing, that is quite expensive and large in size. In this paper a model of impulse voltage generator with capacitive load of pin type insulator is studied by simulation method and by an experimental setup. A ten stage high voltage impulse generator (HVIG) is designed and implemented for different applications. In this proposed model, the cost has been reduced by using small and cheap capacitors as an alternative for large and expensive ones while achieving the same effectiveness. Effect of the distributed capacitance in each stage is analyzed to prove the effectiveness of the model. Different values of front and tail resistances have been used to get IEC standard waveforms. Results reveal the effectiveness at reduced cost of the proposed model.

• Journal of the Korean Wood Science and Technology
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• v.43 no.6
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• pp.876-883
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• 2015

Han-green project, which pursues Korean style post and beam timber house with traditional construction technique of Han-ok, has been carried out in KFRI (Korea Forest Research Institute) since 2006. Recently, the improvement of its building energy performance was studied with energy-saving elements. This study was conducted to provide the insulation details of building envelopes in a post-beam timber house for recent enhanced insulation standards and following effect on building energy performance. The level of thermal transmittance (U-value) values of building envelopes was composed of two stages: present Korean insulation standards and passive house. To evaluate building energy performance, the building airtightness values of two stages was ACH50 = $3.0h^{-1}$ for common domestic timber house constructed recently, and ACH50 = $0.6h^{-1}$ for passive house. Consequently, four cases of the building energy performance according to the combination of U-value with airtightness were evaluated. The test house for evaluation was located in Seoul and its energy performance was evaluated with CE3 commercial building energy simulation program. The result showed that enhanced insulation from level I to II reduced $14kWh/(m^2{\cdot}a)$ of annual heating energy demand regardless of airtightness.

• Architectural research
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• v.17 no.2
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• pp.75-81
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• 2015

Insulation and condensation performance evaluation (I&CPE) is an important energy analysis. While considerable amount of data are already represented in a Building Information Model (BIM), the lack of interoperability between BIM modeling and I&CPE programs prevents the simulation process from being efficient and accurate. This study proposes a prototype of a BIM-based I&CPE simulation program, in order to enhance the interoperability between BIM modeling and I&CPE programs. This study discusses the information flow process, defines the required information and its level of detail, develops standardized libraries, and finally proposes a prototype that consists of a data extraction module, conversion module, and performance module. The assurance of interoperability between systems might greatly benefit architects and energy professionals.

• Proceedings of the KIPE Conference
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• 2002.11a
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• pp.163-166
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• 2002

Recently, the insulation breakdown accident has been experienced at 6.6kV inverter driving motor. That brought about the reliability degradation of motor driving system.. We need to find the solution with system engineering level. The objectives of this study are developing the appropriate filter for the drive to protect the motor and the Insulation system of motor which Is driven by inverter. We clarify the cause of the deterioration of the inverter driving motor through the analysis of Insulation breakdown accidents.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.227-228
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• 2023

This study is tocompare and analyze the results of hydration heat analysis and on-field measurements using the method with hydration heat difference and insulation curing method for controlling hydration heat in mass concrete. As a result of the analysis, the temperature difference between the center and the surface was predicted very similarly, and the mass concrete surface was controlled to a safe level when evaluating with a temperature crack index, and after being finished, it was confirmed that there was no hydration crack.