자동차 오디오 시스템의 음질 개선 연구

박석태(Seok Tae Park) 한국소음진동공학회 1995 한국소음진동공학회 학술대회논문집 Vol.1995 No.11

Development of High Performance Computing Codes in Direct Boundary Element Method Using Hybrid Method Combined with CPU and GPU

Seok-Tae Park(박석태) 한국소음진동공학회 2019 한국소음진동공학회 논문집 Vol.29 No.3

Various techniques have been proposed to shorten the analysis time of the traditional acoustic direct boundary element method. The overall analysis time can be reduced by vector operations and parallel operations. When constructing the system equation, unnecessary repetitions were reduced and modified separately to increase the analysis speed. To solve the system equations, computation speeds for each case to run on a CPU were compared using LINPACK-, LAPACK-, and MKL-dedicated libraries. Furthermore, when the system equations were solved by hybrid programming using the CPU and GPU, results that were hundreds of times faster could be achieved than when using multiple CPUs. The system matrix had a complex, asymmetric, dense matrix form; thus, direct solution methods were used. A system matrix equation solver code written by the hybrid method using Fortran and C languages was executed in the CUDA core of the GPU, enabling high-speed operations. The prediction results of the input acoustic impedance of a cone horn using the developed direct boundary element method code were in good agreement with the test results. It was possible to perform an acoustic analysis of several thousand degrees of freedom using the developed acoustic direct boundary element method codes at the time of a cup of tea. When using the acoustic boundary element method codes for calculations over 20 000 degrees of freedom and at 200 frequency points, results could be obtained within a few hours.

라우드스피커 주파수 종속 매개변수 유도 및 규명법 비교

박석태,Park, Seok-Tae 한국음향학회 2007 韓國音響學會誌 Vol.26 No.6

본 논문에서는 현재까지 주파수 영역에서 개발된 4종류의 라우드스피커 TS 매개변수 규명법들에 대하여 비교 검토하였다. 보이스 코일 인덕터에 대한 상세한 모델링을 위해 주파수 종속 모델링 기법을 소개하였고 관련된 매개변수들을 유도하였다. 라우드스피커의 동적 질량을 알고 있을 때에 TS 매개변수를 규명하는 방법을 소개하고 이를 실제 라우드스피커에 적용할 때에 고려할 사항들도 기술하였다. 1채널 장비로 전기 임피던스를 측정할 때에는 크기만을 측정하게 되므로 위상값 추정을 위해 최소 위상 변환법을 사용하는 방법도 기술하였다. In this paper it was discussed and compared measured loudspeaker impedance curve with ones reconstructed by TS parameters estimated using four kinds of parameter estimation methods developed in frequency domain. Frequency dependent parameters were introduced and derived using least square error minimization technique. For known dynamic mass TS parameter estimation methods were reviewed and also proved non-uniqueness of these parameters by simulation method. Minimum phase transformation was adopted to derive phase information from magnitude of loudspeaker electrical impedance curve measured by one channel analyzer.

Development of Coupled Analysis in Vibration Finite Element Method and Acoustic Boundary Element Method Using Graphical User Interface

Seok-Tae Park(박석태) 한국소음진동공학회 2020 한국소음진동공학회 학술대회논문집 Vol.2020 No.6

조선미술전람회를 통해 본 '향토성' 개념 연구

박석태(Park, Seok-Tae) 인천대학교 인천학연구원 2004 인천학연구 Vol.3 No.-

After Japan occupied Korea(1910) and really came to build colony. It put up assimilation policy for the civilizing of the East Asia aimed at the rule of colonies on the surface. However, in reality, it is understood by everybody that the above policy was the one aimed at discriminating colonial region as inferior people. And since here lies intentional making self internal (domination) , or making internal stranger (discrimination) consciousness together, I think it played a great role for highlighting the form of a colony. The local color or the color of a native town came to stress the thematic factor through the request of Japanese judging committee members, the request of Japanese judging committee members, as Joseon Art Exhibition began to be held, This request as Joseon Art Exhibition began to be held. We cannot doubt that the above is a part the policy of the colonization of the culture by Japanese government. And it reveals Japanese colonialism by means of the government-sponsored art exhibition and shows that it discriminates the interior land from the exterior land nakedly. We can see that by merely looking at the works of the painters of the corresponding colony which displayed the consciousness of native land by using female as a theme, the orientalism getting out of political thing and stressing noncivilization was applied as it is. Consequently, the consciousness of a native land which appeared to the painters of Joseon Art Exhibition grew up in the local color that is a product of Japanese colonialism. And this consciousness entered another way seeking the disposition of nationalism brings about the making of main land and the color of a native. The common trait which appeared to the art community of Korea is the fact that the Japanese influence criticizing the western modernization and crying out for returning to oriental spirit came to be further stressed through local color. This makes a dual stranger what is non-western and pre-modern aspect, so that Joseon color showed oriental image as non-western and pre-modern view. In particular, this oriental nature shows its characteristic as primitive theme which accepted the fauvism of the western modernism. The local color in government-sponsored art exhibition also makes the interpretation of the dominated. And I think that the deep-seated interpretation of the problem will be accompanied, depending how the local color demanded from the colonial ruler is accepted and developed. Consequently, through this study I compared the local color made by the sponsors of colonialism with the paintings shown at Joseon Art Exhibition, and examined the position of accepting them. However, as the method of the study has a limit in which all-out and multilateral groping, I am going to wait for more advanced study.

충격 시험의 출력 데이터에 기초한 유사잔향 시간을 이용한 도자기의 결함 탐지법

박석태,Park Seok-Tae 한국음향학회 2006 韓國音響學會誌 Vol.25 No.6

도자기 컵의 결함여부를 판정하는 간편한 방법으로 실내에서 충격 시험으로 추정한 유사잔향시간을 사용하는 방법을 제시하였다. 정상적인 도자기 컵과 미세한 균열이 있는 컵에 대하여 충격 시험을 하여 발생하는 충격음에서 구한 슈레더 곡선에서 잔향 시간을 추정하였다. 충격 가진 막대의 종류와 가진 위치, 경계 조건에 따라 잔향 시간을 추정하였고 추정된 잔향 시간으로부터 도자기 컵의 결함 유무를 효과적으로 파악할 수 있는지를 기술하였다 To determine the faults of ceramic cup it is proposed to use pseudo reverberation time concept estimated by impact test in room. Schroeder curves estimated from impact test for a cup with small crack and without one are utilized to estimate pseudo reverberation time. Pseudo reverberation times are compared and discussed according to a sort of impact hammers and impact points and also boundary conditions. As a result. proposed method is proved to be very useful to detect the existence of faults for candidate cups.

21CM 우주전파 수신용 안테나의 제작

박종애,양종만,한석태,박용선,Park, Jong-Ae,Yang, Jong-Man,Han, Seok-Tae,Park, Yong-Seon 한국천문학회 1993 天文學論叢 Vol.8 No.1

We made a pyramidal horn antenna system for 21cm cosmic radio wave. The antenna system has a rectangular waveguide with $TE_{10}$ mode and a copper probe to detect the electromagnetic wave in waveguide. The parameters of the probe are obtained by experiments using two waveguides. Pyramidal horn antenna is designed to get a gain of 20dB. The size of the aperture of this horn is $94cm{\times}74cm$. The beam width of half power is about $14.7^{\circ}$ for the frequency of 1.4GHz. The horn is made of aluminum plate with a thickness of 2mm. The signal from horn and waveguide is amplified in a receiver system and is converted into DC in the detecter. The intensity of the signal is recorded on a chart recorder. We observed the sun using this simple radio telescope and obtained the brightness temperature of $2.2{\times}10^5K$, which indicates that the sun is quiet at 21cm.

10 mm급 원형 마이크로스피커의 가상 스피커 TS 매개변수 규명

박석태(Park, Seok-Tae) 한국소음진동공학회 2007 한국소음진동공학회 논문집 Vol.17 No.11

It was discussed to identify Thiele Small Parameters for Pseudo loudspeaker within 10mm grade microspeaker attached to closed-box using known dynamic mass of moving parts. Also, enhanced circuit model for vented-box micro speaker system was used to more accurately simulate electrical impedance curves for real vented-box microspeaker system and compared to test results. Consequently, it showed that micro speaker could be modeled by pseudo loudspeaker TS parameters similar to general loudspeaker. Vented-box microspeaker model with pseudo loudspeaker TS parameters was well suited to describe real microspeaker. Also, it was proposed to estimate volume of rear closed-box of microspeaker without design specifications.

PSPICE를 이용한 개선된 벤트박스 스피커 시스템 모델링

박석태(Park, Seok-Tae) 한국소음진동공학회 2007 한국소음진동공학회 논문집 Vol.17 No.8

Enhanced PSPICE circuit model for vented-box loudspeaker system with lumped parameters was proposed to more accurately simulate real vented-box loudspeaker system. Frequency dependent parameters were used to model voice coil inductor. Acoustic pressure response curves and electrical impedance curves were simulated and investigated by PSPICE circuit model according to circuit parameters' variations. Finally, it was used to identify faults detection in woofers manufactured by unskilled persons.

모바일 폰용 마이크로스피커의 음향 및 전기 해석

박석태(Seok-Tae Park) 한국소음진동공학회 2014 한국소음진동공학회 논문집 Vol.24 No.7

In this paper, GUI program for microspeaker system simulation program was developed and verified through closed box, vent box and 6th order bandpass enclosure system. By using the pseudo loudspeaker model concept, TS parameters and rear volume of microspeaker were identified. Their suitabilities were proved by comparing test results with simulations of electrical impedance and sound pressure response curves for the three box types; closed box, vent box and 6th order bandpass box. Also, MSSP was found to be effective regardless of the microspeaker’s shape, either circular or rectangular shape. MSSP can be used for the microspeaker system simulation, and can give a general prediction of such as; sound pressure level curve, electrical impedance, diaphragm velocity and displacement curve according to multiple design parameters; diaphragm mass, compliance, force factor, front and rear volume, front and rear ports diameter and length.