• Journal of the Korean Society for Railway
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• v.8 no.6 s.31
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• pp.513-519
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• 2005

The Korean Tilting Train eXpress may produced a strong micro-pressure wave in tunnel exit because of large train/tunnel area ration of conventional railways. This micro-pressure wave causes an impulsive noise which is a serious environmental noise pollution near tunnel exit. Tunnel hood can be the method of reducing the micro-pressure wave in tunnel exit. Therefore, parametric studies for tunnel hood are performed with respect to the hood length and size to investigate the effects of the tunnel hood. Also, axi-symmetric unsteady compressible flow solver was used to analyze train-tunnel relative motion. According to the result of numerical analysis, the maximum micro-pressure wave in tunnel exit is reduced by 56% throughout the hood establishment on conventional railways.

• Proceedings of the KAIS Fall Conference
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• 2005.05a
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• pp.64-66
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• 2005

본 논문은 환경소음과 관련하여 소음이 학교환경에 미치는 영향을 조사하기 위해 소음 공해의 정도를 측정 분석하고 판단하고자 하였다. 소음은 인간에게 정서적 장애를 유발시켜 불쾌감과 노이로제 등을 일으키고 수면 방해. 회화 방해, 작업 능률 저하 등의 원인이 되며 심한 경우 난청 등이 발생 될 수 있다. 본 논문에서는 학교내부의 소음도를 측정하여 보다 나은 면학 환경을 위한 소음 분석평가 결과를 제시하였다.

• Proceedings of the Safety Management and Science Conference
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• 2002.05a
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• pp.285-294
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• 2002

This study is focused on the operation of truck with conscious for environmental logistics system to reduce empty truck movements, and to control running empty truck. With the logistics function, road transport represents the biggest environmental threat. Using nonrenewable natural resources, contributing to air and noise pollution, trucks are environmentally unfriendly. Any steps to reduce transport activity will help minimize negative impact. In particular, noxious emissions must be reduced, but in the long term more environmentally friendly vehicles are required.

• Fire Protection Technology
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• s.29
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• pp.35-38
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• 2000

The apartment houses are increasing for more efficient use of land in our country. Noises form upper story in the silent night makes nervous and uncomfortable. Worst of all, it causes a mental disease. The other side these condition could be a environmental pollution. To prevent like this noise, a variety of sound reducible products are developed and applied in the building construction fields. In this article I' d like to introduce the method of measurement of the impact sound insulation and its practice.

• Advances in aircraft and spacecraft science
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• v.3 no.3
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• pp.243-257
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• 2016

The increase of air traffic volume has brought an increasing amount of issues related to carbon and NOx emissions and noise pollution. Aircraft manufacturers are concentrating their efforts to develop technologies to increase aircraft efficiency and consequently to reduce pollutant discharge and noise emission. Ultra High By-Pass Ratio engine concepts provide reduction of fuel consumption and noise emission thanks to a decrease of the jet velocity exhausting from the engine nozzles. In order to keep same thrust, mass flow and therefore section of fan/nacelle diameter should be increased to compensate velocity reduction. Such feature will lead to close-coupled architectures for engine installation under the wing. A strong jet-wing interaction resulting in a change of turbulent mixing in the aeroacoustic field as well as noise enhancement due to reflection phenomena are therefore expected. On the other hand, pressure fluctuations on the wing as well as on the fuselage represent the forcing loads, which stress panels causing vibrations. Some of these vibrations are re-emitted in the aeroacoustic field as vibration noise, some of them are transmitted in the cockpit as interior noise. In the present work, the interaction between a jet and wing or fuselage is reproduced by a flat surface tangential to an incompressible jet at different radial distances from the nozzle axis. The change in the aerodynamic field due to the presence of the rigid plate was studied by hot wire anemometric measurements, which provided a characterization of mean and fluctuating velocity fields in the jet plume. Pressure fluctuations acting on the flat plate were studied by cavity-mounted microphones which provided point-wise measurements in stream-wise and spanwise directions. Statistical description of velocity and wall pressure fields are determined in terms of Fourier-domain quantities. Scaling laws for pressure auto-spectra and coherence functions are also presented.

• Journal of Preventive Medicine and Public Health
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• v.26 no.1 s.41
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• pp.126-146
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• 1993

To understand the possible hazards to health from the environmental pollution in Korea, the articles reported in 16 daily newspapers were collected and analysed. From 1980 to 1991, ninety three cases were reported. Statistics show that, during the last 2 years, there has been a remarkable increases of health problems reported. The main sources of pollution were plants and the transportation facilities. Except the noise, the exact causative factors were, for the most part, not clealy described. Although many residents complained of neurological symptoms, the exact effects on health were not clearly investigated. The responses of the residents were diverse in the contents of the demand and the method of its pushing, however, the government did not show immediate and consistent counterplans.

• Journal of Korean Elementary Science Education
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• v.28 no.2
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• pp.142-153
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• 2009

The purpose of this study was to survey primary students' perception of the global and local environmental issues. The subjects were 853 fifth primary students in Seoul, Busan, Daejeon, Anyang, Gimpo and Cheongju. The results were as follows: First, the perception level of the global environmental issues were global warming (M=3.99), drinking-water pollution (M=3.92), acid rain (M=3.77), yellow dust (M=3.66), ozone depletion (M=3.57), deforestation in tropical areas (M=3.52), desertification (M=3.36), biodiversity (M=3.40) and their perception level of local environmental issues were waste disposal (M=3.87), air pollution (M=3.74), bad smell (M=3.70), noise (M=3.61), river pollution (M=3.57), soil pollution (M=3.44). Second, it was shown that the metropolitan students' perception levels of environmental issues were higher than the non-metropolitan students'. There wasn't a significant difference in the perception levels of two scale environmental issues and characteristics for sex (p>.05). Third, the result of analyzing on the effects between characteristics was that the factors like 'environmental interest' and 'impact on personal life' had a strong influence on the 'behavior will' to solve the global environmental issues, and 'environmental interest' and 'personal knowledge' had a strong influence on the 'behavior will' to solve the local environmental issues. Fourth, the result of analyzing on the characteristics according to the types of the environmental issues showed that 'personal knowledge', 'environmental interest' and 'behavior will' were high in the global environmental issues (p<.01) and 'virtual contamination', 'human responsibility' and 'impact on personal life' were high in the local environmental issues (p<.05).

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.263-267
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• 2007

Even though Waterpower Generation as pollution-free has its own merit of contribution by supply of good quality electricity, due to the noise made at the time of its operation, a normal mutual communication among the workers and technicians engaging at the hydraulic turbine dynamo room is almost impossible, and since those finishing materials had been used mainly by reflection material, it is actual situation that when working for maintenance in the hydraulic turbine dynamo room, as counterpart's voice vibrates, its working efficiency is difficult to ensure. On such view point, this Research has conducted Psycho-acoustics Experiment about voice Definition using Auralizational Technique, on the object for the hydraulic turbine dynamo room that improved its acoustic performance by computer simulation. As the result of Study, it was known that the clearness of sound with regard to voice information transmission was apparently improved in all items than before improvement. Therefore, it is considering that these results would be utilized usefully when renovation on the hydraulic turbine dynamo room in the future.

• International Journal of Highway Engineering
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• v.17 no.2
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• pp.135-141
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• 2015

PURPOSES : While driving, drivers are usually limited in communicating with others except for using the horn. Excessive use of the horn may cause noise pollution, quarrels between drivers and pedestrians, damage, etc. This study developed a methodology for environmental adaptation and improvements of vehicle horns. METHODS: In this study, we performed a literature review of previous studies and related technologies regarding the overuse and damage of the horn. The proposed methodology employed the paired comparison method, as well as the semantic differential method. These methods can consider various vehicle horns, such as the Sport Utility Vehicle(SUV) Horn, Van Horn, and Buzzer. In addition, we conducted a factor analysis in order to provide a direction for improvement of future horns. This research provides a means of complimenting existing intellectual property related to vehicle horns. RESULTS: As a result, the most preferred of the selected horns were the Buzzer at 86.7%. In addition, based on the factor analysis, the horns could be classified into pleasantness and comfort factors. The results indicate a positive reaction for various vehicle horns. The horn type and size of the process control have been properly developed considering the position of the vehicle and the surrounding noise measurements. CONCLUSIONS : Based on the proposed methodology, public and private sectors can use fundamental data for reasonable traffic-noise control policies.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.734-737
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• 2006

For the comfortable housing life, an urban environment should give comfort and pleasantness to people living in house and in city. There are lots of environmental conditions in city affecting house and life and most of all the noise pollution have been become factor that makes people's life hard without need to say. Recently researches have been performed to create comfortable urban environment and a study on the evaluation of urban environmental sounds is now undergoing. This study aimed to analyse the subjective characteristics through the subjective evaluation to the sounds measured with physical parameters and eventually to find out evaluation method for urban environmental sounds. Vocabularies applied to previous studies were used for the subjective evaluation and sound sources recorded in specific places were presented with picture at the same time.