• Title/Summary/Keyword: Sound control

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A Study on Sound Attenuation of Plant Noise by Enclosure (방음실에 의한 공장설비 소음의 감쇠 효과에 관한 연구)

  • 윤세철;이해경
    • Journal of the Korean Society of Safety
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    • v.9 no.4
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    • pp.119-124
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    • 1994
  • The considerations in the noise control by enclosure are the rise of temperature and sound pressure, transmission loss, absorption coefficient of the materials, the structure of the soundproof panels, an opening and coincidence frequency. But it is very difficult that we obtain the accurate data about those in design, so, the noise reduction after enclosing does not correspond with the calculation. The difference of the noise reduction between the calculation and the measurement was 8.2dBA, and we can obtain the approximate result as the following formula which correct 10dBA, safely.

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Vibration Transmission of Plate-Beam Structure having discontinuity (평판과 보의 연성구조물의 진동에너지 전달특성 분석에 관한 연구)

  • 이형택;김정태
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1997.10a
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    • pp.391-395
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    • 1997
  • The transmission of sound and vibration through structures is of interest in many noise control problems, including architectural acoustics, sound transmission through air craft, spacecraft and ship, and the transmission of noise through machinery and engine enclosures. Statistical Energy Analysis provides a simple and accurate method of approaching these problems. In this paper, comparing the measured coupling loss factor of plate-beam with measured coupling loss factor of mass on the junction will be inspected.

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A Noise Control of Cooler Housing in Large Scale Vertical Motor (대형 수직전동기 Cooler Housing의 이상소음 제어)

  • Joo, W.H.;Kim, D.H.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.11a
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    • pp.132-137
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    • 2000
  • Recently, a severe noise problem was encountered during a shop test of large scale vertical motor. In order to identify the noise characteristics and propose the countermeasure, a variety of experiments such as sound excitation test and contribution analysis was earned out in addition to ordinary noise and vibration measurements. The results showed that the severe noise level was dominated by an acoustic resonance phenonmenon in the cooler housing and higher sound power of outer fan. Through proper treatments, the noise level could be acceptable.

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A Study of the Relationship Between Perceived Health Locus of Control and Quality of Life of Cancer Patients. (암환자가 지각하는 건강통제위 성격과 삶의 질에 관한 관계연구 -방사선요법을 받는 암환자를 중심으로-)

  • Bang, Dong-Wan
    • The Journal of Korean Society for Radiation Therapy
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    • v.12 no.1
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    • pp.69-84
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    • 2000
  • It has been reported that the cancer patient's quality of life is influenced by the perceived health state, self-esteem, health locus of control, social support, whether there is a pain or not, the stage of a disease, the period of a disease, etc, and however, there has been scarcely the research into the fact at home whose cultural and social backgrounds are entire1y different from those of American and European Countries. Accordingly, the author of this thesis performed this study. considering that it is necessary to know the relations between the health locus of control which make it possible to predict the object's behavior related to health and to make plans to induce the object or patient into sound behavior and the quality of life which is closely related to the cancer patient's health, emotion, society, economy, etc. on the whole. This study, a cross-sectional one, includes 135 subjects of $in{\cdot}out$ patients registered at Y University Hospital whose age are more than 20 years, From these patients, data were collected for two weeks through the questionnaire which content concerns about the quality of life and the health locus of control. All the collected data were processed and analyzed through Student's t-test, ANOVA, and the calculation of Pearson Correlation Coefficient, using the SAS program 1. It appeared that the disposition of health locus of control was mostly inclined to the disposition of powerful other health locus of control($28.37{\pm}4.24$), then inclined to internal health locus of control($27.03{\pm}4.17$), and next to chance health locus of control($19.71{\pm}4.97$) By the way. the disposition of powerful other health locus of control appeared a tittle bit higher than internal health locus of control 2. The degree of the quality of life appeared to be 137.54 points in the average of total points and 3.11 in the average evaluation mark. It appeared that the quality of life was most significantly influenced by a factor of 'relations with neighbors' and least significantly influenced by factors of physical conditions and functions. 3. It appeared that the relation between the disposition of health locus of control and the quality of life has nothing to do with the relation between internal health locus of control and the quality of life(r=.1446, P>.05) and also with the relation between the disposition of powerful other health locus of control(r=.0385, P>.05). In conclusion, in the study it has been found out that there is no correlation between the health locus of control and the quality of life, and however it is sound to induce the cancer patient to internal health locus of control. Therefore, it is necessary that under the special circumstances, the cancer patient's behavior should be predicted, thereby inducing the patient to the sound change of his or her behavior. Also in order that the patient enjoys his or her life satisfactorily while living, It is deemed that some kind of multilateral meditation in health and treatment is necessary so that the patient can feel the relief of pain, better health, etc.

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Control of Combustion Instabilities in a Gas Turbine Combustors Through Secondary Fuel Injection (가스터빈 연소기내 2차연료분사에 의한 연소 불안정성의 제어)

  • Jeon, C.H.;Santavicca, Domenic A.
    • Journal of the Korean Society of Combustion
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    • v.3 no.1
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    • pp.59-69
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    • 1998
  • The results of study on the active control of naturally occurring combustion oscillations with a single dominant frequency in an atmospheric dump combustor are presented. Control was achieved by an oscillatory infection of secondary fuel at the dump plane. A high speed solenoid valve with a maximum frequency of 250Hz was used as the actuator and a sound level meter, located at the combustor exit, measured the pressure fluctuations which served as the feedback signal for the control loop. Instability characteristics were mapped over a range of mean mixing section velocities from 6.7 m/s-9.3 m/s and with three mixing conditions. Different fuel/air mixing conditions were investigated by introducing varying percentages of primary fuel at two locations, one at the entrance to the mixing section and one 6 mixing tube diameters upstream of the dump plane. Control studies were conducted at a mean velocity of 9.3 m/s, with an air temperature of $415^{\circ}C$, and from flame blowout to the stoichiometric condition.

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A Study on Digital Sound Source based LED Color Matching Algorism using Moving Average Filter (이동평균 필터방식을 이용한 디지털음원 기반 LED컬러 매칭 알고리즘에 관한 연구)

  • Lee, Seonhee;Lee, Junghoon;Cho, Juphil
    • Journal of Satellite, Information and Communications
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    • v.9 no.4
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    • pp.69-72
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    • 2014
  • Recently, lighting systems using audio signal of audible frequency and frequency spectrum of visible lighting are studied. And various related products are being sold and released commercially. Also demands of emotional matching algorithm and system which includes effective and methodical designs are being increased. And the importance related with this scheme has increased. In this Paper, we configures a system for digital sound source based LED color control. And we develop algorithm to control LED color for the system configuration. Also we demonstrated the usefulness of the algorithm through experiment with simulation using LED color control system. We expected to be useful in a variety of fields and applications using proposed digital music based LED color control system.

Control of Sound Pressure Inside a Flow Excited Resonator (유동가진 공명기 내부의 음압 제어)

  • Hwang, Cheol-Ho;Park, Jong-Beom
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.11a
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    • pp.196-199
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    • 2005
  • Flow traveling over a cavity opening forms a vortex due to unstable shear layer and induces an aerodynamic pressure excitation from the diffusion of the vortex convecting out of the trailing edge of the opening. The interaction between the excitation force and the cavity response sustains resonance in the resonator(cavity) and locked-in vortex shedding at the leading edge of the opening. The aerodynamic excitation force can be described from the diffusion of the vortex over the trailing edge and the level of its diffusivity is related to the strength of vorticity seeded at the loading edge. In this study, the control scheme of the internal pressure oscillation was proposed from regulating the vorticity at the leading edge by use of an oscillating spoiler. It was found that the relative motion between the spoiler and the air mass at the cavity opening influenced vorticity strength and the control was achieved by direct feedback of the cavity pressure fluctuation to the actuator.

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A Study on the Evaluation of Acoustic Performance for Music Room in Middle School Using Auralization (가청화를 이용한 중학교 음악실의 음향성능 평가에 관한 연구)

  • Soul, Soo-Hwan;Kang, Gyu-Sun;Kim, Jae-Soo
    • Journal of the Korean housing association
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    • v.19 no.4
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    • pp.49-57
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    • 2008
  • The case study for this research is a middle school music room located in Iksan City, Korea. Although the room is used for teaching music, indiscreet sound-absorbing materials were applied within the space. Accordingly, a number of difficulties have been experienced when using the room. During a music lesson, the sound-volume is inadequate for music appreciation, while the music performance has an arid sound due to an insufficient echo. In order to control the obstructive factors resulting from a short Reverberation Time, the acoustic factor is optimized in this study by using an Acoustic Simulation, following an arrangement of Acoustic Design. A Psycho-acoustics Experiment was conducted using the Auralizational Technique, whereby the Virtual Acoustic Field can be experienced at the design stage.

Sound's Direction Detection and Speech Recognition System for Humanoid Active Audition

  • Kim, Hyun-Don;Choi, Jong-Suk;Lee, Chang-Hoon;Park, Gwi-Tea;Kim, Mun-Sang
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.633-638
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    • 2003
  • In this paper, we propose a humanoid active audition system which detects the direction of sound and performs speech recognition using just three microphones. Compared with previous researches, this system which has simpler algorithm, fewer microphones and better amplifier shows better performance. In order to verify our system's performance, we install the proposed active audition system to the home service robot, called Hombot II, which has been developed at the KIST (Korea Institute of Science and Technology), thus we confirm excellent performance by experimental results

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Realtime Stereo Sound Image Expansion System Using Hass Effect& Phase shifting (선착효과 및 위상처리를 이용한 실시간 스테레오 음상 확장 시스템 구현)

  • 이종철;이상훈
    • Proceedings of the IEEK Conference
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    • 1998.10a
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    • pp.1227-1230
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    • 1998
  • Phase control methods are used to expand the sound image in general AV system. However, these methods are effective only to the signal under 1kHz, and the listener must be located in front center of the speaker system. In this paper, we realize the realtime processing system in which phase shifting method is dominant at low frequency and precedence effect is dominant at high frequency. Two sound cards are used to process the audio signal in realtime with 16 bits stereo channel of 44.1 kHz sampling frequency. And the analog circuit is designed to process the phase shifting. In experiments the usefulness of the proposed stereo system is confirmed.

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