• 음성과학
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• 제12권4호
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• pp.167-180
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• 2005

The present study examines the phonetic realizations of the unstressed weak vowel /e/ in English words produced by native and Korean ESL speakers. Traditionally, the stressed elements in utterance are considered to be prominent. In this sense, the unstressed weak vowel /e/ is predicted to be shorter in length, lower in pitch and intensity than the stressed vowels. The experiment shows that native English speakers correlate the unstressed weak vowel /e/ with both shorter duration and lower pitch; Korean ESL speakers correlate it with lower pitch only. We cannot find any significant statistical difference in intensity between /e/ and the stressed vowels in both cases. This study suggests it is important to acquire and produce the correct prosodic correlates of the unstressed weak vowel /e/ for Korean ESL speakers to command more natural English intonation, since /e/ is the most common vowel in English speech and consists of the English foot rhythm along with stressed vowels.

• Tribology and Lubricants
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• 제24권5호
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• pp.221-227
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• 2008

This paper presents a step-by-step design of noncircular gears. From the diagram of angular velocity ratio of a noncircular gear pair, the pitch curves of the two mating gears are determined, and the perimeter of the pitch curve has been divided into equal-length segments by the number of teeth. A master tooth profile, which is a composite curve of circular arcs that represents involute, has been introduced. A noncircular gear pair has been designed by imposing the master tooth on the divided points of the pitch curve, and a full fillet has been achieved between neighbour teeth. Thus, the whole profile of the noncircular gear is a composite curve of arcs only, and consequently NC codes for wire EDM can be easily generated.

• 대한전자공학회논문지
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• 제24권3호
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• pp.381-386
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• 1987

By the speech production model, the first positive peak in a pitch interval of the voiced speech is mainly affected by the glottis and the first formant component, known as a typical energy source of the voiced speech. From these characteristics, the energy parameter can be replaced by the area of the area of the positve peak in a pitch interval, which parameter is generally used for classification of speech signals. In this method, the changed energy parameter is independent of window length applied for analysis, and the pitch can be extracted smultaneously. Furthermore, the energy can be extracted in the pitch period unit.

• 문화기술의 융합
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• 제8권5호
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• pp.713-721
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• 2022

LED 비디오월을 방송 현장에서 사용하기 위해서는 몇 가지 알아두어야 할 사항이 있다. 첫째, 픽셀이 촘촘히 배열되어 있기 때문에 짧은 배열 주기로 인한 무아레 현상이 나타날 수 있고, 둘째, 픽셀 간의 거리(픽셀피치)가 촬영하는 카메라 이미지 센서에 기록될 수 있다. 무아레 현상이 발생하거나 픽셀피치가 관찰되게 되면 시청자의 입장에서는 불편함을 느끼게 된다. 무아레 현상은 카메라의 촬영거리나 각도를 조정하면서 감소시킬 수 있지만, 픽셀피치가 이미지 센서에 녹화되는 걸 방지하기 위해서는 LED 비디오월과 카메라와의 거리를 충분히 확보하거나, 거리가 확보된 상태에서도 픽셀피치가 녹화되지 않도록 방송 현장에서 사용되는 줌렌즈의 배율을 적절하게 변화시켜 운용해야 한다. 원하는 화각을 얻기 위해 배율을 변경시켜 초점거리를 변동시키게 되면 의도치 않게 픽셀피치가 녹화되는 결과를 초래할 수 있다. 본 논문에서는 비디오월과의 거리가 충분히 확보된 상태에서 줌렌즈의 배율을 변경하면서 픽셀피치가 관찰되지 않는 범위에 대해 알아보았다. LED 비디오월에 영상을 재생시켜 B4 마운트 줌렌즈를 장착한 HD 카메라와 서버를 사용해 LED 비디오월 상태를 녹화하였고, TV 화면으로 재생하여 픽셀피치가 관찰되는지 확인해 보았다.

• 대한기계학회논문집B
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• 제27권3호
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• pp.357-366
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• 2003

An experimental study is performed to investigate characteristics of near of wakes of circular cylinders with serrated fins using a hot-wire anemometer for various freestream velocities. The main focus of this paper is to investigate a reason why a vortex formation length is increased suddenly. Velocity of the fluid which flow through fins decreases as fin's height and freestream velocity increases and fin pitch decreases, and a thickness of boundary layer increases. The finned tube has a lower velocity gradient when the higher boundary layer grows. This velocity gradient on finned tube makes a weak shear force in the wake and moves to downstream in a state of lower momentum transfer between the freestream and the wake. The phenomenon makes a vortex formation length increased suddenly. The fluctuations of the velocity distributions on the finned tube and (equation omitted) = 1.0 contour line in the vortex formation region decreases when the fin height increases and the pitch decreases.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제37회 추계학술대회논문집
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• pp.575-578
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• 2011

추련편향 개념은 최신의 초음속 전투기에 적용되어 사용되고 있다. 본 연구는 추력편향노즐의 성능특성을 쉴리렌기법을 이용한 충격파 가시화를 통하여 제시한다. 피치 각 변화와 피치플랩길이 변화라는 추력편향노즐의 기하학적인 특성에 따른 실험평가를 수행하고, 이러한 연구를 통하여 추력편향노즐의 초음속 유동특성을 분석하였다. 추력편향노즐의 총 추력은 편향각도가 증가함에 따라 감소되며, 추력손실이 가장 적으면서 적절한 편향 효과를 가지는 최적의 플랩 길이비가 존재한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 A
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• pp.427-430
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• 1992

In this paper, we proposed an algorithm for the musical note recognition. Firstly, a given bit-mapped music score image is converted to a set of individual note pattern images via vertical projection. Then, the pitch of a note is determinal by comparison in the note-head position with the reference five-lines. Also, the length of a note is found via leader clustering with a set of normalized note patterns. Finally, a datafile to play the music is obtained using the pitch and length of musical notes. Experimental results with a simple musical score image show that the proposed scheme is performed well.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.1133-1135
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• 2004

Superconducting transmission power cable is one of interesting parts in power application using high temperature superconducting wire. One of important parameters in high-temperature superconducting (HTSC) cable design is transport current distribution because it is related with current transmission capacity and ac loss. In this paper, the transport current and magnetic field distributions at conducting layers were investigated through the analysis of the equivalent circuit for HTSC power cable with shield layer. The transport current distribution due to the pitch length and winding direction was improved in case of HTSC power cable with shield layer.

• 한국수학사학회지
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• 제5권1호
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• pp.81-95
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• 1988

In Akhakkyebom(낙학궤범), one of the greatest Korean Sources, a great mistake was found in the lengths of the pitch pipes. Whanjong(황종) from which the other eleven pitches are calculated, is nine inches by decimal system. But the rest are from 9inches by nonary system. To find out how such a contradictory combination could put into so great a book, all the sources available wereexamined. In the process of investigating the numeral change of the lengths of the pitchpipes, it was found that fixation of this contradictory combination was due to the tradiction of Confucianism, which is specialized by its adherence of the old. SongHyon(성현) couldn't understand well enough Tsai Yuan-ting's(몽원정) Account of the science of the pitch pipes in Lu-luhsin-shui(율여신서), Neither could Yi Hye-gu(이혜구) who translated Akhakkwebom(낙학궤범) into Korean. The parts they misunderstood were pointed out and explained as it should be in this thesis. Several other accounts of the science of the pitch pipes like Chu Tsai-yu's and Jing Farng's are also explained. The Pitch-pipes which were said to have been made by Pak Yon(박연) were found out to be of Chu Tsai-yu's. Those which Yi Sang dok(이상덕) wrote were one of Pak Yon's achievements turned out to be of Tsai Yuen-ting's(몽원정), And othe interesting mistakes were pointed out in thesis thesis. Most of these mistakes were made, I think, because of the lack of the study on the historical background. That's why I tried to examine all the sources available on pitch-pipes. In the lengths of the pitch-pipes preserved in Shih-chi(사기) by Ssu-ma Ch'ien(사마천), several letters were found to have been misprinted. Some 칠's should be “십” and the letter “일” in Hyopchong(황종) should be “칠”. I couldn't deal with all the lengths of the pitch-pipes in this thesis. Especially the real length of the old measure of Whangjong(황종) made by PakYon(박연) is remained still unknown. I believe a lot more study should be poured on this field to know our traditional music as it was.

• 한국유체기계학회 논문집
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• 제11권1호
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• pp.9-17
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• 2008

A numerical study for three-dimensional laminar flow in the entrance region of helical tubes connected with straight ones is carried out to investigate the effects of Reynolds number, pitch and curvature ratio on the oscillation periods of the flow. The fully elliptic governing equations were solved by means of a finite volume method. The fully developed laminar flow boundary condition was applied at the straight tube inlet. This results cover a curvature ratio range of 1/10${\sim}$1/320, a pitch range of 0.0${\sim}$3.2, and a Reynolds number range of 62.5${\sim}$2000. A comparison is made with previous experimental correlations and numerical data. The developments of velocity, local and average friction factors are discussed. The average friction factors are oscillatory in the entrance region of helical pipes. It has been found that the angle required for the flow to be similarly developed is most affected by the curvature ratio. The pitch and Reynolds number do not have any significant effect on the angle. The characteristic angle ${\phi}_c(={\phi}/sqrt{\delta})$, or the characteristic length to diameter ratio $s_c(=l\sqrt{\delta} cos(atan{\lambda})/d)$, can be useful to represent the development of flow in helical tubes. As the pitch increases and as the curvature ratio and Reynolds number decrease, the amplitude and the number of flow oscillations along the main streamwise direction decrease.