• KIEAE Journal
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• v.9 no.1
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• pp.99-106
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• 2009

This study aims to survey the acoustical environment in the region around airport where there are various transportation noises such as aircraft noise, railway noise and traffic noise, and to analyze the subjective response on the noise to the people who live in house or work in office nearby airport. Measurement and subjective response evaluation were carried out at the same time and outdoor noise level was measured all day long to calculate one day results such as average Leq or one day WECPNL etc. The results showed that the military aircraft produces very high level comparing with commercial aircraft, for instance the sound level of commercial outdoor was lower than that of military aircraft indoor. Double and triple window were more effective for controlling the noise than single window, which showed the possibility of sound insulation treatment by installing windows having higher sound insulation performance. Finally the subjective response was resulted that the most annoying noise is from aircraft and counterplan they hope is 'airport moving out'. Leq 65 dB(A), the criteria value of sound insulation treatment, was corresponding to the subjective response of median annoyance '4' out of 7th scale.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.643-648
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• 1997

Concern for noise problems of a commercial aircraft in community and cabin is increasing due to the more restrictive regulation and customer requirements. This paper introduces to the work packages of the aircraft noise engineer for the development of a commercial aircraft. First of all, the noise engineer establish the design requirement and objectives(DR&O). Then the design and analysis are performed to satisfy with the DR&O during the conceptual and preliminary design phase. And the test and evaluation(T&E) are carried out to verify the analysis results and to acquire the type certification.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.425-429
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• 2007

The noise problem has been a public interest for several years in Korea. Especially, the noises which were emitted from aircrafts on the airport and in the air have injurious effects on people over a vast range. Hence, there need vast data on the aircraft noise to evaluate the effect of various parameters. In present study, the works which consist of social surveys and noise measurements were conducted at points near the airport and the airbase. Total of 1,784 participants give effective responses in forty-five areas nearby the measurement points. Questionnaires asked the responses concerned with attitude, noise sensitivity, directive effects, secondary effects, annoyance and attempts to lower noise level exposed. From the field survey, the doseresponse relationship of community response to aircraft noise was established and there are different characteristics between civil and military aircraft. Though the study is still continuing on a few interest, one among some results is that %HA (%highly annoyed) of civil aircraft is higher than military's under the 70 WECPNL.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.131-134
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• 2005

This study examine the annoyance of transportation noise exposure and found the survey method about which noise induces more disturbance or annoyance when more than two kinds of noise exist. This study describes the noise annoyance survey performed in the vicinity of Sin-wol interchange. This residential area was exposed to aircraft noise and traffic noise simultaneously and aircraft noise exposure of this area is about 81 WECPNL, traffic noise exposure is about 81.2 dB(A) nearby road. Noise sources are grouped into three part, traffic noise, aircraft noise and community noise. The questionnaire includes how often, how loud each noise is heard. Also this deals with comparative annoyance reaction from specific noise sources such as aircraft or traffic and its disturbance of daily activities. Facade noise mapping are executed by using a commercial noise mapping software.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.42-47
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• 2014

In this paper, fatigue life analysis of each structure was performed through theoretical analysis method at design stage in order to verify the success or failure of the store's acoustic noise durability according to the Method 515.5 standard of MIL-STD-810F. In addition, experimental analysis was carried out through the ground and flight test by manufacturing the measuring store, and verification of the sound durability was completed through the flight test after manufacture of the actual store. Furthermore, the commercial FEM code through the PSD calculation method applying measured SPL enables verify the durability of new store components development for the future.

• Current Industrial and Technological Trends in Aerospace
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• v.7 no.2
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• pp.95-105
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• 2009

Fuel cells are applied to the propulsion system of aircraft based on environmental-friendly characteristics with low noise and zero emission of CO2, currently many kinds of UAV and small manned aircraft equipped with fuel cells are being developed. Fuel cells for aircraft typically classified into PEMFC(Proton Exchange Membrane Fuel Cell) type and SOFC(Solid Oxide Fuel Cell) type and the system is developed to adapt missions and operational conditions of aircraft. For UAV, various types of aircraft mostly based on PEM fuel cell technology are investigated for military or commercial uses, and the stability and endurance of system will be improved. For small manned aircraft, many researches are carried out to substitute the propulsion system by fuel cell, also some developments for the higher performance of APU of large commercial aircraft to apply fuel cells are in progress. In the future, a fuel cell aircraft will be expected to improve the reliability and efficiency with higher power density.

• 한국전산유체공학회:학술대회논문집
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• 2002.10a
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• pp.88-94
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• 2002

Curved intakes are commonly used from commercial aircraft to military missile. Sound radiation from the intake of air vehicle affects cabin noise, community noise and military detection. In this paper, Sound radiation from curved intake is computed using the high order, high resolution scheme. The generalized characteristic boundary conditions, adaptive nonlinear artificial dissipation model and conformal mapping for high order, high resolution scheme are used. The geometric change of curved intake and the frequency of acoustic source are considered. Two dimensional Euler equations are solved for theses analyses.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.882-886
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• 2007

People living in the large cities are exposed to high level noise due to road-traffic, railway-traffic and aircraft. Nowadays, some researches are ongoing to reduce the noise by using noise map. However it has to be decided which prediction model is the most suitable in Korea. In this study, it has been focused on railway noise prediction models which are employed in a commercial software(Sound Plan) and developed by Korea Railroad Research Institute, and comparative study of the prediction models has been made.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.3
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• pp.535-544
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• 2017

In-flight aircraft engine performance estimation is one of the key techniques for advanced intelligent engine control and in-flight fault detection, isolation and accommodation. This paper detailed the current performance degradation estimation methods, and an improved hybrid Kalman filter via velocity-based LPV (VLPV) framework for these needs is proposed in this paper. Composed of a nonlinear on-board model (NOBM) and VLPV, the filter shows a hybrid architecture. The outputs of NOBM are used for the baseline of the VLPV Kalman filter, while the system performance degradation factors on-line estimated by the measured real system output deviations are fed back to the NOBM for its updating. In addition, the setting of the process and measurement noise covariance matrices' values are also discussed. By applying it to a commercial turbofan engine, simulation results show the efficiency.

• Journal of Advanced Navigation Technology
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• v.26 no.2
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• pp.91-98
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• 2022

Unmanned aircraft system traffic management (UTM) service for the safe operation of unmanned aerial vehicles (UAV) such as drones using commercial communication networks such as long-term evolution (LTE) and 5G in low-altitude areas of 150m or less is being studied in several countries. In this paper, whether it is possible to secure three-dimensional (3D) coverage for UTM service using the existing LTE cellular network for terrestrial usersis analyzed through simulations. The practicality in the real environment is confirmed by performing performance analysis in the actual topographical environment and the LTE base station layouts in Korea. According to the analysis results, as the altitude increases, the number of line-of-sight (LOS) interference base stations increases, resulting in a worse signal to interference plus noise ratio (SINR), but coverage is secured except for the limited areas within 150m. was confirmed to be possible. In addition, it is confirmed that a significant proportion of outage areas could be reduced by placing a small number of additional base stations for the outage area.