• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
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• pp.539-544
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• 1997

Although the identification of a moving noise source is important in reducing the source power of the transport systems such as airplane or high speed train, the direct measurement of the frequency characteristics is usually difficult due to wind noise when using a microphone running with that noise source. On the other hand the motion of a source causes the frequency characteristics of the pass-by sound measured at a fixed point to be distorted that it is quite difficult to identify the original source characteristics. In this study the relationship between the spectra of the source and the pass-by sound signal is analyzed for a source moving at a constant velocity. The effects of the speed and the frequency characteristics of the source on the pass-by noise spectrum are investigated through numerical simulations.

• 대한기계학회논문집A
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• 제29권12권
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• pp.1597-1604
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• 2005

The identification of a moving noise source is important in reducing the source power of the transport systems such as airplanes or high speed trains. However, the direct measurement using a microphone running with noise source is usually difficult due to wind noise, white the source motion distorts the frequency characteristics of the pass-by sound measured at a fixed point. In this study the relationship between the spectra of the source and the pass-by sound signal is analyzed for an acoustic source moving at a constant velocity. Spectrum of the sound signal measured at a fixed point has an integral relationship with the source spectrum. Nevertheless direct conversion of the measured spectrum to the source spectrum is ill-posed due to the singularity of the integral kernel. Alternatively a differential equation approach is proposed, where the source characteristics can be recovered by solving a differential equation relating the source signal to the distorted measurement in time domain. The parameters such as the source speed and the time origin, required beforehand, are also determined only from the frequency-phase relationship using an auxiliary measurement. With the help of the regularization method, the source signal is successfully recovered. The effects of the parameter errors to the estimated frequency characteristics of the source are investigated through numerical simulations.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.27-33
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• 2001

Linear harmonic analysis is a convenient and generally accurate method to use for the acoustic analysis of intake and exhaust silencers for IC engines. The major uncertainty in this form of modelling is the characterisation of the source, which is inherently nonlinear and time-variant. Experimental methods are generally used to determine the source characteristics, and in particular the indirect method is most suitable for an IC-engine source. With reference to an idealised linear time-variant source, it is found that the characteristics of a time-variant source as determined by the indirect method have no physical relevance. The direct method of experimental measurement appears to have some advantage over the indirect method, although in practice it is difficult to apply to an IC engine source. Again, an idealised linear time-variant source can be used to indicate that the characteristics of a time-variant source as determined by the direct method also have no physical relevance. Strangely, these meaningless measured source properties can nevertheless be used to accurately predict the radiated noise from an IC engine and silencer system.

• 한국수산과학회지
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• 제39권6호
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• pp.480-486
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• 2006

The radiation characteristics of a high-luminance light-emitting diode (LED) light source were studied to evaluate its potential as an energy-saving light source for fishing lamps. The angle of the LED light source with 50% illuminance was $8-15^{\circ}$, and it had strong directional characteristics. The wavelengths at which the radiance and irradiance were maxima were 709, 613, 473, 501, 525, and 465 nm for red, orange, blue, peacock blue, green, and white light, respectively. The underwater transmission characteristics of the LED light source were superior in the order blue, white, peacock blue, and green in optical water type I: blue, peacock blue, white, and green in optical water type II; and blue, peacock blue, green, and white in optical water type III. Setting the underwater transmission characteristics of the LED light source in optical water type I at 100%, the transmission of water types II and III decreased to 67 and 17%, respectively. Based on the underwater transmission characteristics calculated in optical water types I-III, the blue and peacock blue LED light sources can be used as an energy-saving light source for fishing lamps.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.866-870
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• 2001

Measurement techniques for in-duct acoustic source parameters can be classified into the direct method and the load method, according to whether it utilizes an extra external source or not. It is reported that the load methods yield the negative source resistance and the purpose of this paper is to clarify that the time-varying nature of the source is the main cause of this physically implausible result. For this purpose, the direct and load methods for measuring the source characteristics of a simplified fluid machine are simulated using the time domain numerical analysis. In the numerical simulations, the method of characteristics is employed and the source characteristics are calculated from the resultant data. It is shown that the load method results in negative source resistance for some frequencies, whereas the direct method yields positive values for all frequencies considered. It is found that the result of load method is quite sensitive to the change of cylinder pressure or valve profile in contrast to the direct method.

• 복식문화연구
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• 제19권5호
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• pp.945-956
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• 2011

The purpose for this paper is to categorize and analyze the aesthetic characteristics of graphic factors in contemporary fashion design by media source. Focused on play-instinct visual expression in contemporary fashion design and adopted media source following the way of communication design. A variety of literatures and online sites for graphic factors in contemporary fashion was studied. The standard of media source is classified as graphic media-source: photography media-source, typography media-source, illustration media-source. With this standard, expressed ways are as followings. First, graphic media-source in play-instinct expressional fashion design is mostly borrowing existed character or using designer's brand logo. Second, photography media-source in play-instinct expressional fashion design is placed photograph of social issued people in front of shirt. Third, typography media-source in play-instinct expressional contemporary fashion design is mostly expressed social messages or designer's name in brand. Fourth, illustration media-source is the best way to express play-instinct visual expression. Based on these, aesthetic characteristics of graphic factor in contemporary fashion by media source are classified as three: social words, playfulness and information transference. Frequency ratio using media source per aesthetic characteristics is different and these are able to categorize expression way and image feature. In conclusion, expressional way of graphic factors in contemporary fashion design became diverse as social and cultural changing. Frequency of graphic factor use in contemporary fashion is increased than before. This paper suggested that fashion design is one of the way of communicating with people and should be analyzed graphic factors in contemporary fashion design.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1994년도 FIFTH WESTERN PACIFIC REGIONAL ACOUSTICS CONFERENCE SEOUL KOREA
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• pp.893-898
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• 1994

In this paper, the influence of voice source estimation and modeling on speech synthesis and coding is examined and then their new estimation and modeling techniques are proposed and verified by computer simulation. It is known that the existing speech synthesizer produced the speech which is dull and inanimated. These problems are arised from the fact that existing estimation and modeling techniques can not give more accurate voice parameters. Therefore, in this paper we propose a new voice source estimation algorithm and modeling techniques which can not give more accurate voice parameters. Therefore, in this paper we propose a new voice source estimation algorithm and modeling techniques which can represent a variety of source characteristics. First, we divide speech samples in one pitch region into four parts having different characteristics. Second, the vocal-tract parameters and voice source waveforms are estimated in each regions differently using sequential SVD. Third, we propose composite source model as a new voice source model which is represented by weighted sum of pre-defined basis functions. And finally, the weights and time-shift parameters of the proposed composite source model are estimeted uning EM(estimate maximize) algorithm. Experimental results indicate that the proposed estimation and modeling methods can estimate more accurate voice source waveforms and represent various source characteristics.

• 기술혁신학회지
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• 제5권2호
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• pp.212-227
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• 2002

This study reviews the institutional frameworks of Open Source software and develops the stylized facts of Open Source software innovation. Open Source software have to solve two difficult problems for encouraging innovation. First, the source code of Open Source software program should be open and freely distributed and it is very difficult for developers to appropriate the results of their investments. Second, as Open Source software development process is characterized by the participation of communities of developers, it is not easy to coordinate and manipulate the development process. These difficulties of developing Open Source Software have been solved by the particular incentive schemes and coordinating mechanisms. This study reviews the study on the motivation of Open Source software development and the mechanisms which coordinate innovation process of Open Source software with peer review and meritocracy, and how these characteristics promote innovation in Open Source software communities.

• 방송공학회논문지
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• 제21권4호
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• pp.538-551
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• 2016

방송 제작현장에서는 영상 이미지 표현의 광원으로 Tungsten Halogen 광원이 주 광원으로 사용 되어 왔다. Tungsten Halogen 광원은 그동안 개발된 다른 광원보다 태양광원과 유사한 색 재현성으로 각광받아 왔지만 에너지 효율성의 문제점을 가지고 있었다. 최근 대체 광원으로 고효율의 에너지와 긴 수명의 LED광원이 방송 광원으로 주목받기 시작했다. LED광원은 독특한 발광원리 때문에 카메라를 통한 영상 이미지의 색 재현성과 광원에서 투사되는 빛의 질에 있어서 Tungsten Halogen광원과 다른 특성을 가지고 있다. 이런 특성은 LED광원이 방송 광원으로서 도입이 늦어지는 이유이다. 이에 본 연구에서는 LED 광원의 색 재현성과 빛의 질 특성인 평탄도를 측정하여 기준광원인 Tungsten Halogen과 비교하여 방송 광원으로써의 적합성에 대한 실험 데이터를 제시할 것이다. 또한 LED광원이 방송 광원으로서의 확산되기 위해서 필요한 점이 무엇인지 향후 과제와 기준을 제시하고자 한다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.106-111
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• 2001

This paper is a study on the heat generation characteristics of the carbon heating source with high temperature. The main variables of this study are the input current and the amount of carbon heating source. As the results of the experiment in the waste rate of carbon heating source. The case of carbon heating source 300g was large than 500g. As the input current and the temperature are increased, the resistance values of carbon heating source were large. The Joule heat was represented the large value as the amount of heating source decrease with the input current. Finally, the heating source was represented the electrical steady state as the input current is increase.