• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.857-861
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• 2004

An active method that improves low frequency characteristics of a reverberation chamber has been proposed. Spatial uniformity of sound pressure at low frequency has been increased by applying active noise control system. The system acts as frequency selective damping materials, which decreases resonance at low frequency and leave high frequency sound field as it is. Linearity of the chamber, which is essential for sound power measurement in the chamber, is guaranteed since fixed control logic has been adopted. Simple application and tests have been done in a small sized rectangular reverberation chamber which has 400Hz cutoff, Loud speakers were used to simulate a noise source and to construct an active noise control system. The spatial distribution of a sound field at 250Hz, 315Hz and 400Hz bands has been measured before and after control. The standard deviation of sound field has been decreased from 3.4dB to 2.5dB. The results show the possibility of active control system as a sound diffuser.

• 한국음향학회:학술대회논문집
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• 한국음향학회 2000년도 하계학술발표대회 논문집 제19권 1호
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• pp.223-226
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• 2000

Currently a multichannel system for virtual 3-D sound rendering is under development. Robust sound image formation and smooth real time interactivity are main design Points. The system utilizes VBAP algorithm as virtual sound image positioning. Overall system settings can be easily configured. We developed software, RIMA. as a driving Program of the system. At this stage, it is possible to position virtual sound images at arbitrary positions in three-dimensional space. The characteristics of the system are discussed. The system has been applied to the KAIST Bicycle Simulator to generate the virtual sound field.

• 제어로봇시스템학회논문지
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• 제18권4호
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• pp.343-352
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• 2012

To follow a sound source by a mobile robot, the relative position and orientation of the sound source from the mobile robot have been estimated using a microphone array. In this research, the difference among the traveling times of the sound source to each of three microphones has been used to calculate the distance and orientation of the sound source from the mobile robot which carries the microphone array. The cross-correlation between two signals has been applied for detecting the time difference between two signals, which provides reliable and precise value of the time difference comparing to the conventional methods. To generate the tracking direction to the sound source, fuzzy rules are applied and the results are used to control the mobile robot in a real-time. The efficiency of the proposed algorithm has been demonstrated through the real experiments comparing to the conventional approaches.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.608-612
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• 2000

Active control of sound radiation(using active structural acoustic control) from a vibrating rectangular plate by a steady-state harmonic point force disturbance is experimentally studied. Control structural input are achieved by two piezoceramic actuators bonded to the surface of the panel. Two accelerometers are implemented as error sensors. Estimated radiated sound signals using vibro-acoustic path transfer function are used as error signals. The vibro-acoustic path transfer function represents system between accelerometers and microphones. The control approach are based on a multi-channel filtered-x LMS algorithm. The results demonstrate that attenuation of sound levels of 3dB, 13dB are achieved.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.752-760
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• 1993

We research ed on the noise control of a head feeding type combine harvester. It is a kind of combine harvester developed in Japan. And at present, it is used by most Japanese farmer. For a head-feeding type combine harvester it is very difficult to determine the sources of noise because it is a combination of reapers and automatic , threshers and several running parts. However we succeeded in finding out the sound sources of combine harvesters and analyzing their sound by the using sound intensity method. The sound intensity Method is a very up-to-date method to measure and analyze Sound Intensity Levels and sound directions at several measuring point sin a specified area. In this research, first a conventional sound level measurement method is used and secondly the sound intensity method. The first method shows a rather great limitation in allowed exposure duration. The second method shows pin-points the engine itself as being the main source of noise, causing sound flows a ross the operator's seat.

• Journal of Advanced Marine Engineering and Technology
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• 제35권8호
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• pp.1078-1084
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• 2011

본 연구는 팬을 이용한 LED의 온도제어에 대한 것으로 팬에서 발생하는 소음을 최소화하기 위하여 최저소음 때의 풍량을 사용하여 LED의 온도제어에 대한 연구를 행하였다. 또한, LED의 소음 최소화 및 온도제어를 위하여 최저소음 때의 풍량을 이용한 팬의 순차제어에 대해 연구하였다. 제안한 연구를 위해 팬의 최저소음과 연관된 LED의 온도를 측정하고 이 결과들을 이용하여 팬을 이용한 LED 등의 온도 제어실험을 행하였다.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2011년도 후기공동학술대회 논문집
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• pp.99-100
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• 2011

In this paper, a temperature control for LED(Light Emitting Diode) lamp using a cooling fan is studied. An efficient temperature control scheme for the LED lamp using the fan wind at the lowest sound noise is studied. Also, for minimization study of sound noise and temperature control of an LED lamp, a sequential control algorithm using the cooling fan at the lowest sound noise is presented. For the study, after measurement of the minimum sound noise of the fan and related temperature of the LED lamp through tests, experiments on temperature control of the LED lamp using the fan was performed.

• 한국소음진동공학회논문집
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• 제25권8호
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• pp.525-531
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• 2015

Driving sound is an effective element to promote the product identity of a vehicle by providing customers with attractive sound which reflects the concept of a vehicle. Recently, major automakers are focusing on the target sound setting so that the sound can represent the brand image as well as the unique concept of a vehicle. In this study, a new method of target setting for the driving sound will be introduced based on using formant filter and musical harmonics characteristics. In addition, a target sound suggested from this method will be realized and verified by using active noise control in vehicle.

• 한국소음진동공학회논문집
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• 제15권8호
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• pp.891-896
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• 2005

On the basis of theoretical studies on the effect of the cylinders attached to semi-infinite screens, the tangential sound power-transport parallel to the surface of the attached cylinder is minimized by means of a secondary sound field, which is generated from a part of the attached cylinder. The numerical study shows the possibility of deflecting the incident sound by minimizing the sound field of the upper sections. The acoustical shadow region was more pronounced in both near- and far-field compared to the passive case with rigid surface, i.e. without active control. For a relatively wide frequency range it was possible to enhance shielding effects only with few secondary sources and error microphones. In this paper effects of control parameters on the actively controlled sound field near the top edge of noise barriers are studied. Results of numerical study and model measurements are shown and discussed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.278-281
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• 2004

Multiple sound sources are controlled to enhance sound power within a zone of interest. The problem of enhancing acoustic variable can be regarded as an optimization problem, which seeks an optimal control input that maximizes the acoustic variable. It should be noted that enhancing sound power of a selected region requires both the magnitude and direction to be controlled. For this reason, two kinds of cost functions that can represent the spatially distributed intensity are defined. Theoretical formulation shows the possibility of sound power control in a zone, and the detailed procedures of the proposed method are validated by numerical simulations.