• The Journal of the Acoustical Society of Korea
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• v.21 no.4
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• pp.146-146
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• 2002

We present a new technique for achieving source separation when given only a single channel recording. The main idea is based on exploiting the inherent time structure of sound sources by learning a priori sets of time-domain basis functions that encode the sources in a statistically efficient manner. We derive a learning algorithm using a maximum likelihood approach given the observed single channel data and sets of basis functions. For each time point we infer the source parameters and their contribution factors. This inference is possible due to the prior knowledge of the basis functions and the associated coefficient densities. A flexible model for density estimation allows accurate modeling of the observation, and our experimental results exhibit a high level of separation performance for simulated mixtures as well as real environment recordings employing mixtures of two different sources. We show separation results of two music signals as well as the separation of two voice signals.

• Korean journal of applied entomology
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• v.32 no.1
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• pp.76-82
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• 1993

Phonotaxis of the African mole cricket, Gryllotalpa africana palisot de Beauvois, was investigated in 1990 and 1992 at the agronomy Experiment Station of Korea Ginseng & Tobacco Research Institute in Hwaseong-gun, Kyonggi-do, Male adults produced calling sounds (calling songs) through the openings of subsurface burrows. Intensities of the sound were 77-80 dB at 15 cm above the openings. When tape recordings of male calling songs were broadcasted outdoors at 105-110 dB by two horn speakers installed at the center of a 1.4 m diameter-funnel, flying adults were attracted for 1.5 hours from about 30 minutes after sunset. Among attracted adults, 14.3-16.9% landed in the funnel, and 65.7-74.7% landed on the ground within 2m form the sound source. Females were 66.7-74.3%, which seemed to be due to the sex ratio of the population in the field. Adults landing in the funnel and at the distance of within 2m from the center of the funnel were tend to be a little more than those attracted to a blacklight trap.

• Journal of Broadcast Engineering
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• v.20 no.3
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• pp.408-413
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• 2015

Recently, According to increasing interest to original sound Karaoke instrument, MIDI type karaoke manufacturer attempt to make more cheap method instead of original recoding method. The specific method is to make the original sound accompaniment to remove only the voice of the singer in the singer music album. In this paper, a system to separate vocal components from music accompaniment for stereo recordings were proposed. Proposed system consists of two stages. The first stage is a vocal detection. This stage classifies an input into vocal and non vocal portions by using SVM with MFCC. In the second stage, selective frequency subtractions were performed at each frequency bin in vocal portions. In this case, it is determined in consideration not only the energies for each frequency bin but also the phase of the each frequency bin at each channel signal. Listening test with removed vocal music from proposed system show relatively high satisfactory level.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.2
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• pp.195-202
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• 2015

Hundreds of Steller sea lions, Eumetopias jubatus, migrate from Sakhalin and the northern Kuril Islands to Hokkaido in Japan every winter. During this migration, they may use their roaring sounds to navigate and to maintain their groups. We recorded the roars of wild Steller sea lions that had landed on reefs on the west coast of Hokkaido, and those of captive sea lions, while making video recordings. The fundamental frequency ($F_0$), Formant frequency ($F_1$), pulse repetition rate (PRR), and duration of syllables (T) were analyzed using a sonagraph. $F_0$, $F_1$, and PRR of the roars emitted by captive sea lions increased in the order male, female. By contrast, the $F_1$ of wild males was lower than that of females, while the $F_0$ and PRR of wild males and females did not differ statistically. These results suggest regional differences between the five groups showed that.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.4
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• pp.458-465
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• 2010

Hundreds of Steller sea lions, Eumetopias jubatus, migrate from Sakhalin and the northern Kuril Islands to Hokkaido every winter. During this migration, they may use their roaring sounds to navigate and to maintain their groups. We recorded the roars of wild Steller sea lions that had landed on reefs on the west coast of Hokkaido, and those of captive sea lions, while making video recordings. A total of 300 roars of wild sea lions and 870 roars of captive sea lions were sampled. The fundamental frequency ($F_0$), formant frequency ($F_1$), pulse repetition rate (PRR), and duration of syllables (T) were analyzed using a sonagraph. $F_0$, $F_1$, and PRR of the roars emitted by captive sea lions increased in the order male, female, and juvenile. By contrast, the $F_1$ of wild males was lower than that of females, while the $F_0$ and PRR of wild males and females did not differ statistically. Moreover, the $F_0$ and $F_1$ frequencies for captive sea lions were higher than those of wild sea lions, while PRR in captive sea lions was lower than in wild sea lions. Since there was a linear relationship between body length and the $F_0$ and $F_1$ frequencies in captive sea lions, the body length distribution of wild sea lions could be estimated from the $F_0$ and $F_1$ frequency distribution using a regression equation. These results roughly agree with the body length distribution derived from photographic geometry. As the volume of the oral cavity and the length of the vocal cords are generally proportional to body length, sampled roars can provide useful information about a population, such as the body length distribution and sex ratio.

• Journal of Korea Entertainment Industry Association
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• v.14 no.3
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• pp.229-236
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• 2020

In this paper, the tone of Daegeum, one of the most representative wind instruments of our country, was analyzed. Daegeum is widely used as Jeongak Daegeum and Sanjo Daegeum, which are played in royal and wind music, and Sanjo Daegeum is mainly played in Sanjo, Sinawi and folk music. The reason why the two pieces of music are being played in different music genres is due to the improvement of the length of the pipe and the location of the finger holes, allowing the Sanjo Daegeum to perform faster than Jeongak Daegeum, apply various techniques, and make the choice of musical instruments harmonized with music by making the difference in tone. For timber analysis of Jeongak Daegeum and Sanjo Daegeum, the composition of the overtones was visually verified through Spectrogram and Spectrum Analizer, in which the results of recordings were recorded by playing octave low, flat, and octave high positions with the same power. From this, Jeongak Daegeum, which is rich in low-pitched sound, harmonizes with solemn music such as royal music, and Sanjo Daegeum, which has a relatively clear high-pitched sound, is well suited to bright music such as solo music.

• The Journal of Korean Medicine
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• v.32 no.6
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• pp.10-17
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• 2011

Background: Vibration response imaging (VRI) is a new technology that records energy generated by airflow during the respiration cycle. Analysis of lung sound using VRI may overcome the limitations of auscultation. Objectives: To set a VRI standard for healthy Koreans, we conducted a clinical assessment to evaluate breath sound images and quantification in healthy subjects and compared the findings with reported breath sound characteristics. Methods: Recordings were performed using the VRIxp. Eighty subjects took a deep breath four times during a 12-second interval while sitting upright. The quantitative aspect was analyzed using the VRI quantitative lung data (QLD) for total left lung, total right lung and for six lung regions: left upper lung (LUL), left middle lung (LML), left lower lung (LLL), right upper lung (RUL), right middle lung (RML), right lower lung (RLL). The qualitative aspect was provided through image assessments by three reviewers. Results: In all regions the left lung had significantly higher QLD than the right lung (P<0.005, paired t-test). The inter-rater agreement was 0.78. 84% of the images were found normal by the final assessment. Among the 16% (n=13) of images with abnormal final assessment, the most common flawed features were dynamic image (77%, n=10) and maximum energy frame (MEF) shape (77%, n=10). No significant differences were found between males and females for QLD but there were significant differences in qualitative aspects including dynamic images, MEF shape, and missing LLL. Conclusion: The characteristics of healthy Koreans are similar to those of Western subjects reported previously. VRI is easy to use and objective, and so is helpful to diagnose patients with respiratory diseases and to monitor the progress of diseases after medical treatments.

• Journal of Korea Entertainment Industry Association
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• v.13 no.2
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• pp.93-100
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• 2019

Dynamic Compressors in vocal recordings of modern pop music are essential equipment. Dynamic compressors are applied not only to the mix for listening to music but also to the monitor for the singer to listen to his voice along with the accompaniment while the singer is recording. This study is an experimental study on the effects of a dynamic compressor applied to a monitor environment on the vocal performance of a singer. 10 participating singers participated in the blind test to test how the vocals heard through the monitor would be affected by the 1:1, 2:1 and 4:1 compression ratio. Experimental results show that the higher the compression ratio applied to the monitor, the bigger the song, the brighter the tone, but the pitch becomes finer inaccuracy on the bigger dynamic part of the song. In post-interviews with blinds, it was found that singers generally preferred to hear compressed sound through a compressor on the monitor. Since the music used in the experiment was a ballad with a wide dynamic range, it could not be generalized to all kind of music recordings, but it could provide important implications for the monitoring of recording sites. In addition, We hope that the cognitive science approach to recording technology will be added based on this paper which has been studied through empirical studies on the effect of the monitor environment on the singing voice.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.16 no.1
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• pp.10-14
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• 2005

Background and Objectives : Vowels are characterized on the basis of formant patterns. The first formant(F1) is determined by high-low placement of the tongue, and the second formant (F2) by front-back placement of the tongue. The fundamental frequency(F0) of a soprano often exceed the normal frequency of the first formant. And the vocal intensity is boosted when F0 is high and a harmonic coincides with a formant. This is called a formant tuning. Experienced singers thus learned how to tune their formants over a resonable range by lowering the tongue to maximize their vocal intensity. So, the current study aimed to identify the formant tuning in one experienced soprano by comparing the first formants of vowel [i] in three different voice production : speech, ascending scale, and vocalize. Materials and Method : All voices recordings of vowel [i] in speech, ascending scale (from F4 note to A4 note), and vocalize(:Ridente la calam") were made with digital audio tape-corder in a sound treated room. And the captured data were analyzed by the long term average(LTA) power spectrum using the FFT algorithm of the Computerized Speech Lab(CSL, Kay elementrics, Model, 4300B). Results : Although the first formant of vowel [i] in speech was 238Hz, those of ascending scale [i] were 377Hz, 405Hz, 453Hz respectively in F4(349z), G4(392Hz), A4(440Hz) note, and 722Hz, 820Hz, 918Hz respectively in F5 (698Hz), G5(784Hz), A5(880Hz) note. In vocalize, first formants of [i] were 380Hz, 398Hz, 453Hz respectively in F4, G4, A4 note, and 720Hz, 821Hz, 890Hz respectively in F5, G5, A5 note. Conclusion : These results showed that the first formant of ascending scale and vocalize sustained higher frequency than fundamental frequency in high pitch. This finding implicates that the formant tuning of vowel [i] in ascending scale was also noted in vocalize.

• Journal of the Korean Institute of Landscape Architecture
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• v.50 no.2
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• pp.64-75
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• 2022

The purpose of this study is to illuminate the meaning of the soundscapes of two bells, Daeheung-dong Cathedral and Sungsimdang in Eunghang-dong, which are landmarks and attractions in the historic downtown of Daejeon. The study was conducted through field research and recordings, as well as literature studies of related documents and soundscape theory. Daejeon city was developed along with Daejeon Railway Station during the Japanese colonial period in the early 20th century. As the Chungnam Provincial Office moved to Daejeon, Daeheung-dong and Eunhang-dong in Jung-gu, located near Daejeon Station, developed significantly and formed the city centre. As major administrative agencies moved to Seo-gu in the 1990s, the downtown area of Daejeon was on a path of decline, and the decline accelerated with the development of Sejong city. Meanwhile, Daeheung-dong Cathedral and Sungsimdang, founded by refugees during the Korean War, firmly protected the historic downtown area of Daejeon, where the natives left. Daeheung-dong Cathedral, established during the Japanese colonial period, is a local landmark with a history of 100 years in 2019. Sungsimdang, which was created with the backdrop of the Korean War, is also a historical and cultural asset with a history of 60 years and a local landmark selected as the No. 1 tourist attraction in Daejeon. This research, which started from the sound of the bells of Daeheung-dong Cathedral, heard even in the neighboring residential areas, led to the discovery of the bells of Sungsimdang in Eunhang-dong, located across the street. In this paper, the bells of Daeheung-dong Cathedral and Eunhang-dong Sungsimdang have characteristics of soundmarks according to R. Murray Schafer's soundscape sound category. Furthermore, this paper attempted to analyze the meaning of the two bells according to the relatively recent EU soundscape definition. These two bells are signal sounds at the surface level, but are the sound marks of the historic downtown area of Daejeon at the deep level. Although there are outward differences in size, scale, frequency, and famousness, these two bells share a meaning in terms of locality and good influence with the historicity and spatiality of a special relationship. The implication of this study is that the two places should be preserved as local historical and cultural assets not only as visual landmarks but also as sound marks in the urban regeneration or urban development of Jung-gu, Daejeon.