• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.167-168
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• 2003

우리나라는 1987년 7월부터 휘발유 및 LPG 연료 사용 자동차에 배출가스 저감장치인 삼원촉매(3way catalytic converter)를 부착하였고 배출가스 측정방법도 중량규제(ｇ/km)로 하였다. 그러나 이륜자동차는 2001년부터 2행정기관에 대해서 산화촉매를 부착토록 하였으며, 오염물질 측정방법도 2000년에 이르러 정지가동시 측정하는 농도규제(%)에서 트랜지언트(transient)방법에 의한 중량규제(ｇ/km)로 강화하였다. (중략)

• Journal of Korean Society of Disaster and Security
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• v.16 no.3
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• pp.45-56
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• 2023

In this study, the application of ANC (Active Noise Control) technology to address inter-floor noise was explored. To achieve this, an ANC system was developed to manage the heavy impact sound within the frequency range of 40 to 500 Hz. The ANC system utilized an adaptive filter employing a feedforward approach based on the Fx-LMS algorithm. To set up the ANC system, a comprehensive analysis of various variables within the system was performed using computational simulations. This process enabled the identification of optimal filter settings and system configuration arrangements. In addition, the ANC system was implemented in the inter-floor noise test room at the Korea Conformity Laboratories (KCL). Through a certified standard testing procedure, it was confirmed that the ANC system led to a 4 dB reduction in inter-floor noise when the system was activated compared to when it was turned off. The results of this study indicate that the developed ANC system has an effect significant enough to elevate the rating criteria by one level for heavy impact sound.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.1
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• pp.13-20
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• 2022

Aircraft weight is an important factor affecting performance and fuel efficiency. In the conceptual design stage of the aircraft, the process of balancing cost and weight is performed using empirical formulas such as fuel consumption cost per weight in estimating element weight. In addition, when an airline operates an aircraft, it promotes fuel efficiency improvement, fuel saving and carbon reduction through weight management activities. The relationship between changes in aircraft weight and changes in fuel consumption is called the cost of weight, and the cost of weight is used to evaluate the effect of adding or reducing weight to an aircraft on fuel consumption. In this study, the problems of the existing cost of weight calculation method are identified, and a new cost of weight calculation method is introduced to solve the problem. Using Breguet's Range Formula and actual flight data of the A350-900 aircraft, two weight costs are calculated based on take-off weight and landing weight. In conclusion, it was suggested that it is reasonable to use the cost of weight based on the take-off weight and the landing weight for other purposes. In particular, the cost of weight based on the landing weight can be used as an empirical formula for estimating element weight and optimizing cost and weight in the conceptual design stage of similar aircraft.

• Journal of Food Hygiene and Safety
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• v.30 no.2
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• pp.166-172
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• 2015

This study was performed to develop treatment method for reducing microbial contamination on Daruma (a semi-processed product of seasoned and dried squid) by combination of strong acidic hypochlorous water (SAHW) and ultrasonic waves (UW). The available chlorine concentration, oxidation reduction potential (ORP) and pH of SAHW were $69.67{\pm}0.58ppm$, $1071.33{\pm}4.16mV$ and 2.79, respectively. The 1.49 log CFU/g of viable cell count and 1.32 log CFU/g of Staphylococcus aureus was reduced, and Escherichia coli was reduced below detection limit when the Daruma was treated with 20 times (w/v) of sodium hypochlorite solution (SHS) for 120 min. The 3.62 log CFU/g of viable cell count and 3.22 log CFU/g of Staphylococcus aureus was reduced, and Escherichia coli was reduced below detection limit when the Daruma was treated with 20 times (w/v) of SAHW for 120 min. The antibacterial effects of SAHW were stronger than those of SHS at same available chroline concentration. SAHW treatment after washing strongly alkalic electrolyzed water (SAEW) showed better bactericidal effects than SAHW treatment only. The 4.0 log CFU/g of viable cell count was reduced, S. aureus was reduced below regulation limit (Log 2.0 CFU/g), and E. coli was reduced below detection limit when the Daruma was treated with 20 times (w/v) of SAHW for 90 min after washing with 20 times (w/v) of SAEW for 60 min. The viable cell number was reduced below detection limit and S. aureus was reduced below regulation limit when the Daruma was treated with 20 times (w/v) of SAHW for 60 min in ultrasonic washer. E. coli was reduced below detection limit when the Daruma was treated with 20 times (w/v) of SAHW for 10 min in ultrasonic washer. These results suggest that combination of SAHW and UW may be a good technique to reduce the microbial contamination in daruma.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.325-326
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• 2008

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.528-529
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• 2009

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.596-597
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• 2011

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.8
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• pp.124-129
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• 2009

Recently, there has been a growing global interest in environmental conservation, and the field of electric power equipment has been working to become more environment-friendly. Accordingly the 154[kV] low noise transformer is developed through the research. The low noise transformer decreases the audible noise level but the low noise transformer has several changes in the increase of weight and volume and the application of rubber damper. Therefore it is necessary to inspect the test, transportation, installation and operation about field application. In this paper, we investigate the standards of the audible noise level, the weight and volume of the transportation, the installation space and operation in order for effective field application.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.5
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• pp.533-540
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• 2008

In this study, a new slab system where a part of precast slab is connected each other by viscoelastic material is proposed and numerical analysis is performed to evaluate the effect of the connection between the material and PC slab on the vibration and noise control. Substructuring is introduced to develop the equation of motion for the slab system. In addition, the optimal properties of viscoelastic material are investigated. For the performance evaluation of the new slab system, the sound power and acceleration responses of the slab are compared with those of two way slab and one way slab, respectively. Numerical analysis results show that the sound power of the new slab system can be reduced by viscoelastic material significantly.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.296-299
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• 2004

단열 완충재의 하부단면에서 양각 형태가 전체 면적에서 .차지하는 비율에 따라 진동 충격음 저감량을 실험하였다. 양각 형태가 차지하는 비율이 높더라도 진동 충격음 저감량에는 큰 성능을 나타내지 않았다. 바닥 구조에서 슬래브와 상판 사이에 단열완충재를 설치할 경우 중량 충격음이 오히려 증가하는 경향을 보이고 있다. 이것은 뜬 바닥 구조에서 완충재의 설치로 인하여 슬래브와 상판간의 거동이 다르게 발생하기 때문이다.