• Journal of the Korean Society of Environmental Restoration Technology
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• v.14 no.5
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• pp.53-67
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• 2011

The major objective of this study was to quantify the effects of substrate depth and substrate composition on the development of sedum etc., in a sloped rooftop (6 : 12 pitch) environment during a 4-year period. The experiment was conducted from 2006 October to 2010 December under several conditions without soil erosion control : two substrate depth (5cm, 10cm), four substrate composition (A5N3C2, A3N3C4, A6C4, G5L3C2: A: artificial lightweight soil, N : natural soil, G : granite decomposed soil, C : leave composite, L : loess), four sloped roof direction ($E40^{\circ}W$, $W40^{\circ}N$, $S40^{\circ}W$, $N40^{\circ}E$). In this experiment 4 sedum etc., were used: Sedum sarmentosum, Sedum kamtschaticum, Sedum rupestre, Sedum telephium, flowering herbs (mixed seed : Taraxacum platycarpum, Lotus corniculatus, Aster yomena, Aster koraiensis), western grasses (mixed seed : Tall fescue, Creeping redfescue, Bermuda grass, Perennial ryegrass). The establishment factor had two levels : succulent shoot establishment (sedum), seeding (flowering herbs, western grasses). 1. Enkamat, as it bring about top soil exfoliation, was unsuitable material for soil erosion control. 2. Sedum species exhibited greater growth at a substrate depth of 10cm relative to 5cm. All flowering herbs and western grasses established only at a substrate depth of 5cm were died. A substrate depth of 5cm was not suited in sloped rooftop greening without maintenance. If additional soil erosion control will be supplemented, a substrate depth of 10cm in sloped rooftop greening without maintenance was considered suitable. 3. For all substrate depth and composition, the most abundant species was Sedum kamtschaticum. The percentage of surviving Sedum kamtschaticum was 73.4% at a substrate depth of 10cm in autumn 2007 one year after the roof vegetation had been established. But the percentage of surviving other sedum were 33.3%~51.9%, therefor mulching for soil erosion control was essential after rooftop establishment in extensive sloped roof greening was proved. To raise the ratio of plant survival, complete establishment of plant root at substrate was considered essential before rooftop establishment. 4. There was a significant interaction between biomass and substrate moisture content. There were also a significant difference of substrate moisture and erosion among substrate composition. The moisture content of A6C4 was highest, the resistance to erosion of A5N3C2 was highest among substrate composition. The biomass of plants were not significantly higher in A5N3C2 and A6C4 relative to A3N3C4 and G5L3C2, For substrate moisture and erosion resistance, A5N3C2 and A6C4 were considered suitable in sloped rooftop greening without maintenance. 5. There were significant difference among roof slope direction on the substrate moisture. Especially, the substrate moisture content of $S40^{\circ}W$ was lower relative to that of $N40^{\circ}E$, that guessed by solar radiation and erosion.

• The Journal of Korean Academy of Prosthodontics
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• v.39 no.1
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• pp.71-83
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• 2001

The purpose of this study was to compare the effects of various surface treatments by measuring removal torque on bone healing around titanium implants. 40 Screw-shaped cp titanium implants with length of 4mm, outer diameter of 3.75mm, and pitch-height of 0.5mm were used Group 1 was left as machined(control), Group 2 was blasted with $50{\mu}m\;Al_2O_3$, group 3 was blasted and etched in etching solution($NH_4OH : H_2O_2:H_2O= 1 : 1 : 5$) at $90^{\circ}C$ for 1 minute group 4 was blasted and oxidated under pure oxygen at $800^{\circ}C$. The implant surface roughness was analyzed with SEM and CLSM(Confocal Laser Scanning Microscope) and implants were placed in proximal tibial metaphysis of 10 New Zealand White rabbits. After 3 months of healing period, removal torque of each implant was measured to compare bone healing around implant. The results obtained were as follows 1. In SEM view, blasting increased the roughness of the surface, but etching of that rough surface decreased the roughness due to the removal of the tip of the peak. Oxidation also decreased the roughness due to formation of needle-like oxide grains on the implant surface. 2. The Sa value from CLSM was least in the machined group($0.47{\mu}m$), greatest in blasted group($1.25{\mu}m$), and the value decreased after etching($0.91{\mu}m$) and oxidation($0.94{\mu}m$). 3. The removal torque of etched group(24.5Ncm) was greater than that of machined group(16.7Ncm) (P<0.05), and was greatest in the oxidated group(40.3Ncm) and the blasted group(34.7Ncm).

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.8
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• pp.582-589
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• 2019

The dynamic balancing test of helicopter main rotor blades is a blade rotation test conducted on the ground to make the track of each blade and the load on each pitch rod to a similar level before the flight tests. The purpose of the test is to reduce the vibration occurring on main rotor system as a result of dissimilarity of each blade. The RTB test has been performed for a long period at Whirl Tower Test Facility located in Goheung Flight Centre, accumulating its data. As the amount of the results has become increasingly enormous the needs for the development of database system has been raised to manage the data with effective method. This research aimed to describe the development of Dynamic-Balancing Database System for the RTB test results. For the design of the database system the informations of RTB test results have been categorized into properties, connecting each others according to its logical meaning, and comprised into a database system with relational elements. It has been shown in this paper that the Dynamic Balancing database system enables to effectively accumulate the RTB test data and to be utilized for the data analysis.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.33 no.2
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• pp.89-96
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• 2022

Background and Objectives The quality of life after thyroidectomy, such as voice change, is considered to be as important as control of the disease. In this study, we aimed to evaluate changes in both subjective and objective voice parameters after thyroidectomy resulting in normal morbidity of the vocal cords. Materials and Method In this prospective cohort study, 204 patients who underwent thyroidectomy with or without central neck dissection at a single referral center from Feb 2015 to Aug 2016 were enrolled. All patients underwent prospective voice evaluations including both subjective and objective assessments preoperatively and then at 2 weeks, 3, 6, and 12 months postoperatively. Temporal changes of the voice parameters were analyzed. Results Values of the subjective assessment tool worsened during the early postoperative follow-up period and did not recover to the preoperative values at 12 months postoperatively. The maximal phonation time gradually decreased, whereas most objective parameters, including maximal vocal pitch (MVP), reached preoperative values at 3-6 months postoperatively. The initial decrease in MVP was significantly greater in patients undergoing total thyroidectomy, and their MVP recovery time was faster than that of patients undergoing lobectomy (p=0.001). Patients whose external branch of the superior laryngeal nerve was confirmed intact by electroidentification showed no difference in recovery speed compared with patients without electroindentification (p=0.102), although the initial decrease in MVP was lower with electroidentification. Conclusion Subjective assessment in voice quality and maximal phonation time after thyroidectomy did not show recovery to preoperative values. Aggravation of MVP was associated with surgical extent and electroidentification.

• (The) Research of the performance art and culture
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• no.43
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• pp.79-120
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• 2021

Nagyangchun is a Dangak that has been handed down to the present time with Boheoja as a Saak of the Song Dynasty which was introduced in the Goryeo Dynasty. The title and lyrics of Nagyangchun are conveyed in the Dangakjo of Goryeosa-akji and the Jeungbomunheonbigo. The remaining scores containing Nagyangchun include Akjangyoram, Sogagwonbo Vol.4 and Vol.6 of the Joseon Dynasty and Aakbu-akbo, the 6th Aaksaeng-gyogwacheol, Leewangjikaakbu-oseonakbo during the Japanese colonial period. Besides, the current melody of Nagyangchun is based on Hangugeumak and Gugakjeonjib published by the National Gugak Center. This paper aims to examine how Nagyangchun, which is currently being performed at the National Gugak Center, went through the process of change to have the same structure and form as it is now using these scores as a research subject. The study results are summarized as follows. First, the song of Nagyangchun, which was originally Saak but transmitted as an instrumental piece without lyrics, first appeared in the Hangugeumak Vol.16 and Gugakjeonjib Vol.7 published by the National Gugak Center in 1978 and 1979. In this process, the Janggu added by Kim Ki-soo is now disappearing and is replaced by Jwago. Second, though the five notes of 黃, 太, 仲, 林, and 南 have been maintained unchanged since the Akjangyoram, the pitch of 無/應 and 夾/姑, which appear once each, gradually rises and is unified into 應 and 姑 during the period of Aaksaeng-gyogwacheol or at the latest Leewangjikaakbu-oseonakbo, and reached the present. Third, the current melody of Nagyangchun consists of a structure in which the tones and range of each phrase rises within the form of Mijeonsa (a·b·c·d) and Mihusa (e·b'·c'·d'). Particularly, except for the a-type and e-type melodies, which are the introduction for the Mijeonsa and Mihusa, the remaining melodic types show a gradually descending structure within the corresponding phrase, so the structure of ascending and descending is generally in harmony. Forth, the Ganeum that appeared from Aakbu-akbo are currently classified into seven types, and they appear in ascending pitches of 2nd, 3rd, 4th, and 5th and play a role in smoothly or fluently connecting melodic progression. Fifth, after Akjangyoram, Nagyangchun, which had been handed down as an instrumental piece without lyrics, was restored in 1960 by Lee Hye-gu, and is being passed down as the form of male and female vocals added to the instrumental accompaniment. As a result of examining the current Nagyangchun, which was formed through the process of change after Akjangyoram, it was found that there were tasks that required reconsideration of the current Nagyangchun, which is being played at the National Gugak Center, such as the arrangement of Janggu, the identification of the key, and the investigation of the lyrics. When follow-up studies are continued in the future, it will be able to contribute to the cultural transmission of Nagyangchun.

• (The) Research of the performance art and culture
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• no.36
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• pp.415-440
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• 2018

On September 23, 2015, the Ministry of Education announced the 2015 revision of educational curriculum which aimed at 'cultivating creative talents' based on the Article 23, Section 2 of the Elementary and Secondary Education Law. As a result, music curriculum have also been partially revised, which seems to maintain the 2009 revision of music curriculum. Although Jeongganbo 井間譜 is already exposed in the music curriculum for the third and forth grades of elementary school, the learning content about how to read Jeongganbo and how to express the pitch and length of sound including the origin of its name and the background of its invention are dealt with specifically in the fifth and sixth grades. Jeongganbo is known as the oldest mensural notation in the Orient created by King Sejong of the Joseon Dynasty in the middle of the $15^{th}$ century, and it was used for the first time in Sejong sillok akbo 世宗實錄樂譜 (Scores in the Annals of King Sejong), the oldest musical score still in existence. However, in the music textbooks as well as the most of specialized books related to the Korean traditional music, it is uncritically accepted without providing clear grounds that Sejong invented Jeongganbo himself. If so, it is necessary to investigate on which grounds it is claimed that Sejong invented Jeongganbo. This paper first examined the grounds of the proposition that "Sejong invented Jeongganbo," which is introduced in the music textbooks for the fifth and sixth grades of elementary school, by separating it into Sejong's creation of Sinak 新樂 (new music), Sejo's invention of Jeongganbo and Sejong's invention of Hangeul. Next, this paper examined how the subject of the invention of Jeongganbo has been described in the textbooks for the fifth and sixth grades in elementary school based on the 2009 revision of music curriculum, and suggested the direction of a desirable music education by pointing out the related problems. According to historical records and circumstances such as Sejong's creation of Sinak, Sejo's invention of Jeongganbo with 16 Jeonggan (square) in one vertical line, Sejong's invention of Hangeul and so on, it seems to be the most reasonable that Sejong is the subject of the invention of Jeongganbo as of now. However, the attitude of the musical academy to accept and educate the unclear thing as if it is a fact does not seem desirable. Therefore, I suggest that it should be described "Jeongganbo was invented in the period of Sejong" or "it is supposed that Jeongganbo was invented by Sejong" rather than presenting "Sejong made Jeongganbo" or "created" until revealing the clear evidence about the subject of Jeongganbo.

• Journal of Korea Entertainment Industry Association
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• v.15 no.2
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• pp.35-46
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• 2021

The purpose of this research is to analyze Soon Chul Jung's children's songs, who is one of the four great children's songwriters in Korea along with Geuk Young Yoon, Nan Pa Hong and Tae Jun Park. Soon Chul Jung has contributed by actively participate into children's movement at Japanese colonial period through writing self-composed children's songs. Since children's songs are made for the age group without the sense of sound, children's songs necessitate 'easy to sing-along' melody writing process. Like so, when writing the melody that are easy to be sang along, utilization of development technique using a unit called motive can be the potent way. This method has an advantage of being sang more with ease if actively implemented, and can be done by utilizing the smallest unit of the melody called motive, especially by lightly transform and repeat the unit, consequently structuring the song altogether. To investigate and analyze this motive-based development technique of Soon Chul Jung's songs, 38 out of 40 written songs considered eligible for the research were confirmed and chosen from 'Soon Chul Jung's bibliography and choreography' and each songs were analyzed based on 17 different development techniques which were standardized in the textbook 'Melody in Songwriting' adopted as a textbook of the Berklee college of Music, and also compared these song-writing pipelines with other great songwriters' representatives mentioned above. As a result, it was almost linear that the song's pitch variation in combination with thinning or extension were used frequently and repeatedly, otherwise implicating melody duplication for more than 2 bars and motive repetition were not in his favor, while these methods were often used when writing children's songs. This finding could be viewed as a character of his songwriting.