• Title/Summary/Keyword: acoustic window

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Multiple octave-band based genre classification algorithm for music recommendation (음악추천을 위한 다중 옥타브 밴드 기반 장르 분류기)

  • Lim, Shin-Cheol;Jang, Sei-Jin;Lee, Seok-Pil;Kim, Moo-Young
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.15 no.7
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    • pp.1487-1494
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    • 2011
  • In this paper, a novel genre classification algorithm is proposed for music recommendation system. Especially, to improve the classification accuracy, the band-pass filter for octave-based spectral contrast (OSC) feature is designed considering the psycho-acoustic model and actual frequency range of musical instruments. The GTZAN database including 10 genres was used for 10-fold cross validation experiments. The proposed multiple-octave based OSC produces better accuracy by 2.26% compared with the conventional OSC. The combined feature vector based on the proposed OSC and mel-frequency cepstral coefficient (MFCC) gives even better accuracy.

On Mode Correlation of Solar Acoustic Oscillations

  • Chang, Heon-Young
    • Journal of Astronomy and Space Sciences
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    • v.26 no.3
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    • pp.287-294
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    • 2009
  • In helioseismology it is normally assumed that p-mode oscillations are excited in a statistically independent fashion. Unfortunately, however, this issue is not clearly settled down in that two experiments exist, which apparently look in discrepancy. That is, Appourchaux et al. (2000) looked at bin-to-bin correlation and found no evidence that the assumption is invalid. On the other hand, Roth (2001) reported that p-mode pairs with nearby frequencies tend to be anti-correlated, possibly by a mode-coupling effect. This work is motivated by an idea that one may test if there exists an excess of anticorrelated power variations of pairs of solar p-modes. We have analyzed a 72-day MDI spherical-harmonic time series to examine temporal variations of p-mode power and their correlation. The power variation is computed by a running-window method after the previous study by Roth (2001), and then distribution function of power correlation between mode pairs is produced. We have confirmed Roth's result that there is an excess of anti-correlated p-mode pairs with nearby frequencies. On the other hand, the amount of excess was somewhat smaller than the previous study. Moreover, the distribution function does not exhibit significant change when we paired modes with non-nearby frequencies, implying that the excess is not due to mode coupling. We conclude that the origin of this excess of anticorrelations may not be a solar physical process, by pointing out the possibility of statistical bias playing the central role in producing the excess.

A Study on the Actual Conditions of Indoor Air Quality of Underground Dwellings and the Automatic Ventilating Fan Operated by CO2 Controller and Timer (지하주거의 실내공기환경 실태조사와 CO2 조절기 및 타이머에 의한 환기팬 자동운전에 관한 연구)

  • Kwon, Young Cheol;Park, Jin Chul
    • KIEAE Journal
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    • v.8 no.4
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    • pp.3-9
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    • 2008
  • The rapid urbanization after 1970s caused the shortage of dwellings in urban areas. As the result, the underground dwellings were developed to compensate for the insufficient dwelling spaces. While the underground dwellings have some advantage in the respect of thermal and acoustic environment, they usually have the basic problems in the indoor air quality because of the lack of natural ventilation through small window areas. The purpose of this study is to investigate and to improve the indoor air quality of underground dwellings. Thirty Units in Seoul and Gyung-Gi Province were investigated into the indoor environmental conditions. For the purpose of the improvement of their indoor air quality, Automatically-operated ventilating fan was installed in a sample unit which has worst indoor environmental condition. Then the indoor air quality was monitored when it was operated by $CO_2$ control system and timer. Finally economic feasibility study was made considering the effect of the improvement of indoor air quality. The extra cost for installing timer could be paid back only in 10 months, so timer-installed automatic fan is recommended to improve the indoor air quality of underground dwellings.

Design Method and Preliminary Data Analysis of Subscale Direct-Connect Test Facility for Liquid Ramjet Combustor (I) (액체 램제트 엔진용 소형 연소기 직접 연결식 시험장치의 설계 방법과 시험 데이터 분석 (I))

  • 성홍계;김인식;이규준;김경무;이도형;변종렬;황용석;오석진;한정식
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2003.05a
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    • pp.59-63
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    • 2003
  • This paper describes the conceptual design method of subscale direct-connect test facility for liquid fuel ramjet combustion study and preliminary analysis of test results. The measured pressure signal represents the successful operation of the test facility. The pressure oscillation in combustion chamber shows the dominant frequency of 190Hz, relatively very low frequency to 1L acoustic mode (1200Hz) based on the length of combustor. It is suspected that there were several driving sources, which are vortex street at backward step of combustor, inlet resonance induced by the long length of unchecked inlet, and/or combustor configuration with optical window.

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Development of Speech-Language Therapy Program kMIT for Aphasic Patients Following Brain Injury and Its Clinical Effects (뇌 손상 후 실어증 환자의 언어치료 프로그램 kMIT의 개발 및 임상적 효과)

  • Kim, Hyun-Gi;Kim, Yun-Hee;Ko, Myoung-Hwan;Park, Jong-Ho;Kim, Sun-Sook
    • Speech Sciences
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    • v.9 no.4
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    • pp.237-252
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    • 2002
  • MIT has been applied for nonfluent aphasic patients on the basis of lateralization of brain hemisphere. However, its applications for different languages have some inquiry for aphasic patients because of prosodic and rhythmic differences. The purpose of this study is to develop the Korean Melodic Intonation Therapy program using personal computer and its clinical effects for nonfluent aphasic patients. The algorithm was composed to voice analog signal, PCM, AMDF, Short-time autocorrelation function and center clipping. The main menu contains pitch, waveform, sound intensity and speech files on window. Aphasic patients' intonation patterns overlay on selected kMIT patterns. Three aphasic patients with or without kMIT training participated in this study. Four affirmative sentences and two interrogative sentences were uttered on CSL by stimulus of ST. VOT, VD, Hold and TD were measured on Spectrogram. In addition, articulation disorders and intonation patterns were evaluated objectively on spectrogram. The results indicated that nonfluent aphasic patients with kMIT training group showed some clinical effects of speech intelligibility based on VOT, TD values, articulation evaluation and prosodic pattern changes.

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Breakage Detection of Small-Diameter Tap Using Vision System in High-Speed Tapping Machine with Open Architecture Controller

  • Lee, Don-Jin;Kim, Sun-Ho;Ahn, Jung-Hwan
    • Journal of Mechanical Science and Technology
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    • v.18 no.7
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    • pp.1055-1061
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    • 2004
  • In this research, a vision system for detecting breakages of small-diameter taps, which are rarely detected by the indirect in-process monitoring methods such as acoustic emission, cutting torque and motor current, was developed. Two HMI (Human Machine Interface) programs to embed the developed vision system into a Siemens open architecture controller, 840D, were developed. They are placed in sub-windows of the main window of the 840D and can be activated or deactivated either by a softkey on the operating panel or the M code in the NC part program. In the event that any type of tool breakage is detected, the HMI program issues a command for an automatic tool change or sends an alarm signal to the NC kernel. An evaluation test in a high-speed tapping machine showed that the developed vision system was successful in detecting breakages of small-diameter taps up to M1.

Multiple Sensor Fusion Algorithm for the Altitude Estimation of Deep-Sea UUV, HEMIRE (심해무인잠수정 해미래의 고도정보 추정을 위한 다중센서융합 알고리즘)

  • Kim, Dug-Jin;Kim, Ki-Hun;Lee, Pan-Mook;Cho, Sung-Kwon;Park, Yeoun-Sik
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.12 no.7
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    • pp.1202-1208
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    • 2008
  • This paper represents the multiple sensor fusion algorithm for the deep-sea unmanned underwater vehicles (UUV), composed of a remotely operated vehicle (ROV) 'Hemire' and a depressor 'Henuvy'. The performance of underwater positioning system usually highly depend on that of acoustic sensors such as ultra short base line(USBL), long base line(LBL) and altimeter. A practical sensor fusion algorithm is proposed in the sense of a moving window concept. The performance of the proposed algorithm can be observed by applying the algorithm to the Hemire sea trial data which was measured at the East Sea.

A comparative study of cavitation inception of naval ship's propeller using on-board noise and vibration signals (선체 부착 소음/진동 센서를 이용한 함정 추진기 캐비테이션 초생 분석 비교 연구)

  • Hongseok Jeong;Hanshin Seol
    • The Journal of the Acoustical Society of Korea
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    • v.42 no.3
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    • pp.243-249
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    • 2023
  • The occurrence of cavitation on the propeller is directly linked to the naval ship's survivability, and it is necessary to design a propeller shape that delays the cavitation inception. However, the propeller cavitation can occur under various operating conditions, thus it is important to identify whether the propeller cavitation exists during operation as well as in the design phase. To this end, it is necessary to use noise or vibration signals on board to monitor the cavitation inception. In this study, a hydrophone and an accelerometer were installed on the ship hull right above the propeller to compare the performance of analyzing cavitation inception between acoustic and vibration signals. Also, a high speed camera was used to visually observe the occurrence of cavitation through an observation window. The measured results showed that the spectral shapes between acoustic and vibration signals were different, but the level increases at each frequency band and the overall level of the frequency band from 1 kHz to 10 kHz showed a similar tendency. The Detection of Envelope Modulation On Noise (DEMON) analysis also showed similar results for both acoustic and vibration signals, confirming that both hydrophones and accelerometers can be utilized in the analysis of cavitation inception.

The Design of Broadband Ultrasonic Transducers for Fish Species Identification - Bandwidth Enhancement of a Ultrasonic Transducer Using Double Acoustic Matching Layers- (어종식별을 위한 광대역 초음파 변환기의 설계 ( III ) - 이중음향정합층을 이용한 초음파 변환기의 대역폭 확장 -)

  • 이대재
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.34 no.1
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    • pp.85-95
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    • 1998
  • The broadband ultrasonic transducers have been designed to use in obtaining the broadband echo signals from fish schools in relation to the identification of fish species. The broadening of bandwidth was achieved by attaching double acoustic matching layers on the front face of a Tonpilz transducer consisted of an aluminum head, a piezoelectric ring, a brass tail and to evaluate the performance characteristics, such as the transmitting voltage response(TVR) of transducers. The constructed transducers were tested experimentally and numerically by changing the parameters such as impedances and thicknesses of the head, tail and matching layers, in the water tank. Also, the developed transducer was excited by a chirp signal and the received chirp waveforms were analyzed. According to the measured TVR results, the available 3 dB bandwidth of the transducer with double matching layers of an $Al_O_3/epoxy$ composite of 7 mm thick and a polyurethane window of 18 mm thick was 7.3 kHz with a center frequency of 38.8 kHz, and the maximum and the minimum values of the TVR in this frequency region were 135.7 dB and 132.7 dB re $1\;{\mu}Pa/V$ at 1 m, respectively. Also, the available 3 dB bandwidth of the transducer with double matching layers of an $Al_O_3/epoxy$ composite of 11 mm thick and a polyurethane window of 15 mm thick was 6.2 kHz with a center frequency of 38.6 kHz, and the maximum TVR value in the frequency region was 136.3 dB re $1\;{\mu}Pa/V$ at 1 m. Reasonable agreement between the experimental results and the numerical results for the TVR of the developed transducers was achieved. The frequency dependant characteristics of experimentally observed chirp signals closely matched to the measured TVR results. These results suggest that there is potential for increasing the bandwidth by varying other parameters in the transducer design and the material of the acoustic matching layers.

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A Study on Loose Part Monitoring System in Nuclear Power Plant Based on Neural Network (원전 금속파편시스템에 신경회로망 적용연구)

  • Kim, Jung-Soo;Hwang, In-Koo;Kim, Jung-Tak;Moon, Byung-Soo;Lyou, Joon
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2002.05a
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    • pp.227-230
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    • 2002
  • The Loose Part Monitoring System(LPMS) has been designed to detect, locate and evaluate detached or loosened parts and foreign objects in the reactor coolant system. In this paper, at first, we presents an application of the back propagation neural network. At the preprocessing step, the moving window average filter is adopted to reject the low frequency background noise components. And then, extracting the acoustic signature such as Starting point of impact signal, Rising time, Half period, and Global time, they are used as the inputs to neural network. Secondly, we applied the neural network algorithm to LPMS in order to estimate the mass of loose parts. We trained the impact test data of YGN3 using the backpropagation method. The input parameter for training is Rising Time, Half Period, Maximum amplitude. The result showed that the neural network would be applied to LPMS. Also, applying the neural network to the Practical false alarm data during startup and impact test signal at nuclear power Plant, the false alarms are reduced effectively. 1.

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