• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.6
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• pp.998-1005
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• 2010

Rifling force has a torsion impulse effect on the gun tube and thus generates undesirable vibration of the gun tube about its bore axis, putting additional stress on the projectile. High rifling force at the muzzle of the gun tube may adversely influence the trajectory of the projectile. And, the service life of rifled gun barrels is known to depend on the rifling force. Rifling force along the path of the projectile in the longitudinal direction of the gun tube can be described with projectile mass, projectile velocity, gas pressure curve and rifling angle. Under the same conditions, the character of the rifling of the gun barrel decisively influences the rifling force curve. To reduce the above mentioned harmful effect, locally distinct maximum of rifling force has to be avoided and maximum rifling force needs to be minimized. The best way to minimize the maximum rifling force is to design a rifling angle function so that the rifling force curve has a near trapezoidal shape. In this paper a new approach to make the optimal rifling force curve is described. The rifling angle determining the rifling force is developed by combined Fourier series and polynomial function to satisfy both the convergence and boundary condition matching problems.

• (The) Research of the performance art and culture
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• no.41
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• pp.133-156
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• 2020

This is a paper that examines the meaning and changes of how Dalgang Song, a parenting song, is accepted in pansori works and how it plays a role in the narrative of the work. In Chapter 2, Compared the lyrics of Dalgang-Dalgang in actual parenting scene and Dalgang-Dalgang in Pansori's work. As a result, the songs in Pansori, show some differences in lyrics, but most of them kept the narrative structure intact. Among them, Gangreung-maehwa-ga maintained the phrase "Dalgang-Dalgang" in front and back, making the least changes. Simcheong-ga and Jeokbyeok-ga maintained their epic structures, but the the front and the rear phrase turned into a "Uh huh, Doong doong". And Dalgang-Dalgang was sung mostly by its mother or grandmother at the actual parenting scene, but the song in Pansori, was all sung by men. Dalgang song in Pansori, had a mostly Gyemyeon melody due to the genre characteristics of Pansori. Also Dalgang-Dalgang for actual parenting, was sung with a leisurely, soft beat. But Dalgang song in Pansori's works were sung rhythmical with Jungjungmori rhythm or Jajinmori rhythm to maximize joy. In Chapter 3, I discussed the roles and meanings of Dalgang song contained in Pansori. Dalgang-Dalgang of Simcheong-ga appeared in the crucial process of Sim Hak-kyu's return to will of life through Simcheong after the death of his wife. In Jeokbyeok-ga, Dalgang song also appeared as a tool to recall the happy memories with his son. On the other hand, Dalgang-Dalgang of Gangreung-maehwa-ga played a role of expressing affection for relationships between men and women, not between parents and children. This is beyond the original meaning of parenting, which means the hedonistic and excessive affection of Mr. Gol. The desire to change a relationship between a man and a woman into between parents and children is also found in Kim Yeon-soo's Chunhyang-ga. This change is an example of how the role and meaning of Dalgang song has changed dramatically as it was inserted into pansori. And the reason why Dalgang-Dalgang was so important in the narrative of Pansori was because of The lyrics of the song contain the love of the baby.

• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.1
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• pp.15-21
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• 2015

Rifling Force can be described with projectile velocity, gas pressure and rifling angle, etc. Under the same conditions, the character of the rifling angle decisively influences the rifling force. To reduce the harmful effect, locally distinct maximum of rifling force has to be avoided. The optimal design methodology of rifling angle curve had been developed by combined Fourier series and polynomial function. When it was tried newly to design the rifling angle curve, this design trial caused not to produce the lower rifling force than the existing design. Normally, the curve of the rifling angle is designed first, then the rifling force is set according to the rifling angle curve. However during the cause analysis, new design methodology was established to design the ideal rifling force curve before the rifling angle design. With this new methodology, the above optimal design method was analyzed and its limitation was confirmed.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.879-880
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• 2008

Music can give pleasure to people according to a rhythm, and Musical instrument can make various sounds according to quality of the lumber. A string instrument makes sound by strings so it feels very soft and a brass makes to feel a high pitched tone. A gayageum makes sound by oscillation which is transferred to a resonator when a string is touched. And this sound is very soft and faint. Therefore, in this paper, we researched sound properties of gayageum according to quality of the lumber of musical instrument. As the result of researches, we found that melody is affected by the annual ring of the resonance lumber.

• Journal of Digital Convergence
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• v.15 no.6
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• pp.377-383
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• 2017

In this thesis, Improvisation of Jazz Vocal that can be characterized as Jazz music, namely practice of Scat suggest that way of applied approach that root position of chord and chord tones. Scat plays a solo using reproduced tunes of meaningless scat syllable that is not use the lyrics and melodies, which are written in a score. For this, Using the root position of chord is a reference point that Jazz vocal constructs a musical melody. Singing person can develop that reference point from simple scat to develop increasingly complex scat and can express that musical expression and communion. It analyzed the music functionally with a standard Jazz music 'All of me' as the center from composition of chord tone that improvise song to bass line, bass scat, analysis of chord tones arpeggio and expression. In this thesis, the improvisation of a Jazz vocal that may seem somewhat abstruse and complex could be relatively easy to construct through a gradual approach.

• (The) Research of the performance art and culture
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• no.37
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• pp.157-186
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• 2018

Ulsan Soeburi song was reenacted in the 1980s based on the testimony and songs of late Choi Jae man (1987 death), the last blacksmith of the iron production plant at Dalcheon dong, Ulsan in August 1981. The purpose of this study is to analyze Soeburi song from the musical perspective based on 13 kinds of data including video in 1981, and confirm the changing patterns in the tradition process. The derived results are summarized as follows. In the results of examining Soeburi Song data in 2017, the percussion instruments consist of kkwaenggwari 2 (leading small gong 1, follow small gong 1), jing 2 (large gong 2), buk 4 (drum 4), janggu 4 (double headed drum 4), taepyongso 1 (Korean shawm 1), and Jangdan (rhythm) consists of five such as Jilgut, Jajinmori, Dadeuraegi, Deotbaegi, Jajin Deotbaegi. The vocal songs are sung accompanied by the Deotbaegi Jajin Deotbaegi (beat) of quarter small triplet time, or without accompaniment. The scale is mostly Mi La do's third note or Mi La do re's fourth note, and the range does not exceed one octave. All the cadence tones are the same as La. From the results of observing Soeburi song performance until today after the excavation in 1981, it is found that there are four major changes. First, the composition of the music is differentiated into 'long Jajin (slow fast)', and , , and are added. Second, the singing method is based on 'single cantor + multi post singers' since 1980's reenactment, and a single post singer was also specified from time to time. In addition, , which was performed in 2013, became the foundation of . Third, a melodic change of was observed. All beat structures are quarter small triplet time, but the speed gets slow, Mi La do's three notes are skeletonized to be corrected with high re and low sol, and then the characteristics of Menari tori (the mode appeared in the eastern province of the Korean peninsula) are to be clear. Lastly, the four percussion instruments such as kkwaenggwari, jing, janggu, and buk are frequently used, and depending on the performance, sogo (hand drum), taepyongso, yoryeong (bell) are also added. Jangdan played Jajinmori, Dadeuraegi, Deotbaegi and Jajin Deotbaegi from the beginning, and thereafter, the Jilgut Jangdan was added. Through these results as above, it is confirmed that at the time of the first excavation, a simple form of such as has been changed into a male labor song, the purpose of which has changed, and that the playability has become stronger and changed into a performing arts.