• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.327-328
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• 2014

In enhancing the technologies for the highly efficient and low pollution vehicles, the emitted sound by applying those techniques is degraded, which needs further vibro-acoustic tuning. The point of concern is usually related to the sound quality, and, sometimes, to the direct connection with the pedestrian safety. In this talk, a brief discussion is given to the sound quality issues on the start-stop function, cylinder-on-demand, engine down-sizing, turbo-chargers, road noise, and artificial warning sound.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.439-441
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• 2007

The seoul metropolitan subway has installed 8 lines and about 500 stations to transport 5 million passengers everyday. The underground air pollution level in the subway stations is very severe status, which is very harmful to the commutators and its personals. Although subway roles as such a massive and huge transportation system, the subway doesn't adapt yet any real-time air monitoring system. They have only some hand-held type detector equipments for monitoring air pollution. Therefore subway passengers are exposed to the harmful air pollution environment. The most harmful environmental parameters among the air pollution are known as the dust and sound noise dB level in the subway station. Because the dust is consisted of very small particles, we can't see them easily in dark condition on the platform, but it is very harmful. The monitoring system for air pollution is developed using embedded system attached with 6 different environmental sensors. This system monitors air pollution of dust sound noise, gas, temperature, humidity, inflammable gas, toxic gas in the subway ?station. The sensor unit of the ARM-CPU board and sensor transmits real time environmental data to the main server using Zigbee wireless communication module and TCP/IP network. The main control server receives and displays the real-time environmental data, and it send alarms to the personals when high level value.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.53 no.1
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• pp.19-40
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• 2017

A scientific and objective sound exposure criterion for underwater sound damage on fish has been required since there has been many disputes between an underwater sound maker and a fish damage receiver. The existing criteria are still incomplete scientifically owing to a degree of variability of underwater sounds, diversity of fish hearing sensitivity and damage types, etc. This study reviews existing studies on a hearing mechanism of fish species, manmade underwater sound characteristics and sound exposure assessment parameters, and recent sound exposure criteria. A governing equation for damage coverage estimation and damage coverage dependency on sound source level, ambient noise and transmission loss are also reviewed and interpreted based on sound exposure environments. The foreign and Korean (National Environmental Dispute Medication Commission) criteria are reviewed and compared based on scientific aspects. In addition, the deficit and limit of Korean criteria are presented. The objective of this study is to give a direction for related researches and legislation of sound exposure criteria on fish.

• Journal of Environmental Science International
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• v.13 no.6
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• pp.561-570
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• 2004

This study was carried out to survey the pollution of nonylphenol (NP) in surface sediments around Gwangyang bay and Yeosu sound. NP was suspected chemicals as endocrine disruption. Gwangyang bay is located on the mid south coast of Korea. It is a semi-closed bay which Yeosu petrochemical industrial complex, POSCO (Pohang Steel Company) and Gwangyang container harbor are there. The surface sediments were collected at 15 stations with gravity corer at October, 1999, February, May and August, 2000. Also, the stream and intertidal sediment were collected at 5 sites at August, 2000. Concentrations of NP in surface sediments were in the range of 6.89 to 202.70 ng/g dry wt.. Seasonal range (mean value) of NP is 13.98 to 30.48 (23.46) ng/g dry wt. at October, 10.35 to 54.91 (28.10) ng/g dry wt. at February, 29.05 to 202.70 (82.32) ng/g dry wt. at May and 6.98 to 83.40 (25.37) ng/g dry wt. at August. NP was seasonally fluctuated, and the highest mean value and range was detected at May, 2000. NP was highly distributed in the inner part of Gwangyang bay than Yeosu sound. Concentrations of NP in stream and intertidal sediments showed the highest value in downstream near Yeosu petrochemical industrial complex and Yondung stream. It suggests that the source of NP is industrial wastewater and municipal sewage.

• CELLMED
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• v.9 no.2
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• pp.4.1-4.1
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• 2019

Noise pollution is present all places and affects health negatively. It feels more like that to the patients. When the patient in severe condition is being taken to the emergency room, we have to overcome the siren noise of ambulance. Patients are also more terrified by the sound of sirens. Instead of siren noise, why not use the sound of Buk (Korean drum) for patient, citizens, and social elements including animals and plants?

• IEMEK Journal of Embedded Systems and Applications
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• v.17 no.1
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• pp.9-17
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• 2022

As the COVID-19 pandemic situation worsens, the time spent indoors increases, and the exposure to indoor environmental pollution such as indoor air pollution and noise also increases, causing problems such as deterioration of human health, stress, and discord between neighbors. This paper designs and implements a system that measures and monitors indoor air quality and noise, which are representative evaluation criteria of the indoor environment. The system proposed in this paper consists of a particulate matter measurement subsystem that measures and corrects the concentration of particulate matters to monitor indoor air quality, and a noise measurement subsystem that detects changes in sound and converts it to a sound pressure level. The concentration of indoor particulate matters is measured using a laser-based light scattering method, and an error caused by temperature and humidity is compensated in this paper. For indoor noise measurement, the voltage measured through a microphone is basically measured, Fourier transform is performed to classify it by frequency, and then A-weighting is performed to correct loudness equality. Then, the RMS value is obtained, high-frequency noise is removed by performing time-weighting, and then SPL is obtained. Finally, the equivalent noise level for 1 minute and 5 minutes are calculated to show the indoor noise level. In order to classify noise into direct impact sound and air transmission noise, a piezo vibration sensors is mounted to determine the presence or absence of direct impact transmitted through the wall. For performance evaluation, the error of particulate matter measurement is analyzed through TSI's AM510 instrument. and compare the noise error with CEM's noise measurement system.

• Explosives and Blasting
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• v.29 no.2
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• pp.81-88
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• 2011

Most of the blast pollution that causes complaints is noise and vibration. Hence, special attentions need to be paid to controlling the underwater noise in designing blasting for those areas. This study estimated underwater sound pressure using distance from blasting and charge per delay and underwater sound pressure level using the underwater sound pressure. To identify the validity of the estimated value, the study demonstrated the results at other areas and compared actual results with estimated results.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1998.11a
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• pp.221-224
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• 1998

Environmental pollution is continuously increasing with the economic growth and industrial development. With this trend, soil and groundwater pollution problem has been surfaced as important social issues. Recently, Korean government promulgated the Soil Environment Conservation Act. But there are many problems to control sound soil quality management. Anthropogenic source of pollution such as waste landfill, pesticides, fertilizer, underground storage oil tanks is important as well as natural source such as acid rain and forest fire. The regulation should be expanded to include groundwater preservation as well as soil quality, because soil pollution is closely related to groundwater pollution. Therefore, legal regulations must be expanded to these facilities and take into account technical feasibility and finance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.739-746
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• 2006

Anthropogenic underwater sound such as ship radiated noise, pile driving noise. underwater explosive blast and so on, affects marine animals. This study describes the effects of underwater noise on fishes. The characteristics of noise, fish hearing and response, and sound propagation loss are analysed based on existing results and measured data in marine construction site. Finally, the safety zone range of fish on man made underwater noise is derived.

• Journal of the Korean Institute of Navigation
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• v.22 no.4
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• pp.31-36
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• 1998

The whistle is a very important information source for the safety navigation under foggy weather. But navigator has no concern about this, because it must be achived by human hearing sense and considered as a vague signal. If the range and relative bearing of signal source can be detected automatically, it would be very useful system for preventing marine casualties making a lot of economic loss and environment pollution. Before the algorithm of 2-dimensional sound source tracking system was reported. This paper describes the method that can obtain the time lag between three signals and the theory of cross-correlation analysis and subtraction method for cauculating the time lag by using the digital signal data sequences. And a series of experiments were carried out for various position of sound source in the range from 200cm to 530cm. As a result, we have recognized that sound source tracking system is possible to the sea field with improvement of position error.