• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2021년도 추계학술대회
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• pp.119-120
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• 2021

국내 어선의 해상업무용 무선설비 및 항해 장비는 IEC 60945를 준용한 KN60945_60533의 성능기준을 따르도록 규정하고 있다. LTE-M 송수신기는 해상업무용 무선설비에 포함되지 않아 기존 선박용 장비들과 동일한 기준을 적용받지 않기 때문에, 방사 방출 또는 전도 방출에 의한 간섭으로 기존 해상업무용 무선설비에 가청 소음을 발생하는 원인이 되고 있다. 본 논문에서는 초고속해상무선통신망 무선설비를 소형선으로 확대보급하기 위해 선결 사항으로 위와 같은 간섭 영향의 원인을 분석하고 관련 대책을 검증 제안한다.

• The Journal of the Acoustical Society of Korea
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• 제23권1E호
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• pp.16-18
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• 2004

There have been numerous studies on the enhancement of the noisy speech signal. In this paper, I propose a completely new speech enhancement method, that is, a filtering of a dissonant frequency combined with noise reduction algorithm. The simulation results indicate that the proposed method provides a significant gain in audible improvement compared with the conventional method. Therefore if the proposed enhancement scheme is used as a pre-filter, the perceptual quality of speech is greatly enhanced.

• 말소리와 음성과학
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• 제1권2호
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• pp.31-36
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• 2009

This study attempted to examine the effects of a portable voice feedback device on the hyperfunctional voice behaviors of children with vocal nodules when they wore the device in their daily lives. The device could set fundamental frequency and intensity at optimal levels for the subjects, It produces an audible alarm for inappropriate hyperfunctional voices beyond the preset levels, In addition, the frequency of hyperfunctional voice behaviors was recorded by the device, therefore the users were able to chart their number of hyperfunctional voice behaviors per day, According to results acquired after having subjects wear the device for 12 weeks, the subjects' frequency of hyperfunctional voice behaviors decreased significantly (p < .01). Especially from the first to fourth week, the frequency of their hyperfunctional voice behaviors declined significantly.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권6호
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• pp.287-291
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• 2006

Recently, various applications of permanent-magnet(PM) electric motor have been more increased. Compared with the other electric motors, PM electric motor has cogging torque which results from the interaction between PM of rotor and slot-teeth structure of stator. Audible noise and vibration is caused by this cogging torque. So, the reduction of cogging torque is main designing goal of PM electric motor. The purpose of this paper is to realize the decrease of cogging torque using new experimental design and response surface analysis which is one of the statistical methodologies.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.443-446
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• 1996

This paper presents active silencer by Switched-scheme. Full-bridge inverter to used as operating source of loudspeaker for proposed scheme. And ramp comparison control and hysteresis control are used respectively for active noise control method in this scheme. Computer simulation is accomplished to show the noise reduction characteristics by Switched-scheme. The results of experiment present the effect of audible noise reduction.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1996년도 창립기념 전력전자학술발표회 논문집
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• pp.43-46
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• 1996

The carborne Automatic Train Control(ATC) system keeps automatically optimum train speed code signals from wayside(track) circuit equipment. If there is no response for braking against the over speed detected, the driver will be noticed instantly by visual and audible warning signals. And then the ATC processes into braking mode for safe train operations to prevent any hazards by over speed limit. In this paper we are introduced the novel ATC system which has triple constructed structure made by 32 bit floating point DSP(ADSP21020-20) and process dealed with frequency domain and time domain for detecting signals. Owing to these reason it is no needed several band pass filters used in conventional ATC systems to detect the speed limit frequency. Also system's reliability and tolerance are incremented by adopt to 2 out of 3 logic to the outputs decision.

• 조명전기설비학회논문지
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• 제13권2호
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• pp.24-31
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• 1999

본 논문은 전력설비, 특히 송전선로에 의해서 발생되는 전기환경장해의 특성과 이것의 제한기준에 관한 연구로서, 전기환경기준을 만족하는 송전선로 최적도체선정에 기본이 되며 전기환경장애 민원의 주 항목이 되는 가청소음, 라디오 및 TV장해, 정전유도 그리고 전자유도에 대한 국내 및 세계각국의 관련기준과 법규를 조사, 비교하고 초고압 실증시험선로에서 도출된 결과를 통하여 우리나라 실정에 맞는 전력설비 전기환경 설계기준(안)을 제시하였다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.315-318
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• 2008

Numerical calculation for the 1MW class horizontal axis wind turbine blade has been carried out to estimate the magnitude between discrete noise and random noise. Farassat formula 1A was adopted to get the discrete noise signal, and blade element momentum theory was used to obtain the distribution of the aerodynamic data along the blade span. Fukano's approach was also adopted to calculate the unsteady aerodynamic random noise due to the Karman vortex generation at the trailing edge of the wind turbine blade. From the noise prediction for the 1MW class horizontal axis wind turbine, the frequency band of the discrete noise lies in the infrasound region, and that of the random noise lies in the audible band region.

• 한국소음진동공학회논문집
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• 제18권3호
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• pp.293-298
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• 2008

Non-contact modal testing for longitudinal modes of a pipe is discussed in this work. The suggested method can generate and measure longitudinal vibrations without mechanical contact by using the coupling phenomenon between deformation and magnetic field, known as the magnetostrictive effect. This effect has been used to generate and measure ultrasonic waves, but seldom used to deal with audible vibrations. In this investigation, the validity of the developed method in a typical vibration frequency range is checked with an Inconel pipe being used in nuclear power plants.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.796-801
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• 2007

This research presents a laboratory study about a comparison between two methods that measure a hearing threshold of the Subjects who participated in an experiment of the Jury test. The Subjects heard a signal by a headphone. The Subjects of total 63 persons (man=42, woman=21 persons) participated in an experiment. A test of hearing was divided into two (Top-Down, Bottom-Up) methods. Total time of hearing test was about 80 minute(40min/day). As a results of the hearing test, a hearing threshold of the Subjects who used to wear a headphone was higher than that of the Subjects who not used to wear a headphone. A hearing threshold of a man was higher than that of a woman. The result of hearing test was showed that ISO's hearing threshold(MAF) was lower than a result that get from an experiment.