• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1767-1771
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• 2000

We report the number of calibration and test for acoustic field which were conducted in KRISS between the year of 1990 and 1999. The items contain sound level meter and calibrator for calibration and sound absorption coefficient, transmission loss, sound pressure level of siren, sound pressure level and power of acoustic instrument and relative accessories for test. The data show that the number of them have been increased continuously.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.35-37
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• 2002

Most of the inhabitants living near power line complain wind noise from power line to be problems they can feel directly if there is no countermeasure to remove noise basically. Wind noise from power line happens by tower, insulators, conductor and others in their operating individually or complexly. Wind noise show us several forms like whistle, siren and bullfrog croaking as height of noise source is high and elastic wave tone with low frequency. This paper shows actual conditions and occurrence cause which may be investigated and analyzed on the wind noise, and also prepares mitigation methods and introduces a working sample to reduce a wind noise.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.07a
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• pp.221-222
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• 2018

본 논문에서는 android의 accelerometer sensor를 활용하여 예기치 못한 상황에 사용자를 보호 할 수 있는 어플리케이션을 설계하고 구현한다. 이 어플리케이션은 스마트폰을 흔들 때 accelerometer sensor가 센싱하여 어플리케이션을 자동으로 실행한다. 또한 경광등 소리를 울리고 사용자의 위치정보를 어플리케이션에 저장된 지인의 연락처로 전송한다. 사용자는 자신이 빈번하게 다니는 경로를 저장할 수 있으며, 이 경로에 대한 정보를 연락처에 저장된 지인들에게 제공한다. 이 어플리케이션을 사용하는 사용자는 범죄로부터 자신을 지키고, 위험한 경우 주변 사람들에게 도움을 요청할 수 있는 기능을 제공한다.

• Journal of the Korean Society of Combustion
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• v.14 no.4
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• pp.48-53
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• 2009

This paper describes the forced flame response in a turbulent premixed gas turbine combustor. The fuel was premixed with the air upstream of a choked inlet to avoid equivalence ratio fluctuations. To impose the inlet flow velocity, a siren type modulation device was developed using an AC motor, rotating and static plates. Measurements were made of the velocity fluctuation in the nozzle using hot wire anemometry and of the heat release fluctuation in the combustor using chemiluminescence emission. The test results showed that flame length as well as geometry was strongly dependent upon modulation frequency in addition to operating conditions such as inlet velocity. Convection delay time between the velocity perturbation and heat release fluctuations was calculated using phase information of the transfer function, which agreed well with the results of flame length measurements. Also, basic characteristics of the flame nonlinear response shown in the current test conditions were introduced.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1996.09a
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• pp.117-124
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• 1996

When navigating in or near an area of restricted visibility it is necessary to be heard the whistle bell and/or the siren of lighthouses or ships at times. Even though we can get the brief informations about the property of sound the direction and range of a sound radiator it is not easy to get the accurate informations for decision making. generally the audio frequency is known as 16-20,000Hz but the earshot is shorten and discrimination of sound is more difficult when there is some noise. The sound pressure is 60dB at the moment when human speaks 1 meter away. Usually the noise pressure in a silent room is 40dB and 60dB on the quiet street. In this study we suggest the basic algorithm to trace the direction and range of the source radiator using the signal received through not a physical sense but the microphone sensors and a series of signal of signal processing.

• Journal of the Korean Institute of Navigation
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• v.20 no.4
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• pp.71-79
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• 1996

When navigating in or near an area of restricted visibility, it is necessary to be heard the whistle, bell and/or the siren of lighthouses or ships at times. Even though we can get the brief informations about the property of sound, the direction and range of a sound radiator, it is not enough to get the accurate informations for decision making. Generally the audio frequency is known as 16~20, 000Hz, but the earshot is shorten and discrimination of sound is more difficult when there is some noise. The sound pressure is 60dB at the moment when human speaks 1 meter away. Usually the noise pressures are 40dB in a silent room and 60dB on the quiet street, respectively. It this study, the basic algorithm and a method of signal processing are suggested to trace the direction and range of the source radiator using the signals received through not a physical sense but the microphone sensors.

• Proceedings of the KIPE Conference
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• 2018.11a
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• pp.1-3
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• 2018

When a fire is detected by a sensor of a fire detector, the fire is notified to the manager through the siren. However, if the manager is not indoors, prompt action may not be taken in the event of a fire. In this study, we would like to propose a platform system for fire prevention applying IoT to prevent problems that arise when building manager is absent. This paper presents the structure and operation principle of fire prevention platform system design using IoT, describes the overall system design through fire detector H/W design, micom S/W design and Android application development, and is expected to develop a system that can respond a little faster in case of fire.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.890-892
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• 2022

스마트폰 모바일 앱을 이용한 범죄 예방 시스템은 다양하게 제안되고 개발되어 왔으나, 생활 안전의 유지를 위한 경찰 등 공공 서비스를 위한 인력은 매우 부족한 실정이다. 본 연구는 스마트폰 이용자가 "범죄예방 이론"에 따라 "범죄 취약환경에 및 감시 등 방어기제 부재" 상황에서 신속하게 벗어날 수 있도록 도움을 주는 앱 시스템 필요성 인식에 따라 "긴급 상황 인식 및 자동 알림 신고 앱 시스템"을 기획하여 개발한 결과를 기술하였다.

• The Journal of the Convergence on Culture Technology
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• v.9 no.1
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• pp.153-160
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• 2023

This research experiments on the workers' recognition of the fire alarm sound for sirens and portable loudspeakers in a small construction site. As a result of analyzing the siren alarm sound recognition from measuring on the 1st, 2nd, and 4th floors, the sound was more unrecognizable on the 4th floor than on the 1st, and 1 person on the 1st floor was unable to recognize all sounds. In the case of the 2nd floor, one person could not notice the alarm in the last 3rd trial, and another did not realize it all three times. For the 4th floor, 3 people demonstrated unrecognition in all 3 tests. As a result of analyzing the recognition of portable loudspeaker alarm sounds, 1 person could not recognize all sounds on the first floor. In the case of the 2nd floor, 2 people were confirmed to be unable to notice, and lastly, 4 people could not recognize all trials on the 4th floor. The subjects who didn't recognize the sound were unable to distinguish between portable loudspeaker alarm sound and work noise due to the workspace and obstacles.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.6
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• pp.2748-2760
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• 2018

This paper proposes an audio event classification method based on convolutional neural networks (CNNs). CNN has great advantages of distinguishing complex shapes of image. Proposed system uses the features of audio sound as an input image of CNN. Mel scale filter bank features are extracted from each frame, then the features are concatenated over 40 consecutive frames and as a result, the concatenated frames are regarded as an input image. The output layer of CNN generates probabilities of audio event (e.g. dogs bark, siren, forest). The event probabilities for all images in an audio segment are accumulated, then the audio event having the highest accumulated probability is determined to be the classification result. This proposed method classified thirty audio events with the accuracy of 81.5% for the UrbanSound8K, BBC Sound FX, DCASE2016, and FREESOUND dataset.