• Title/Summary/Keyword: comparative group

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Comparative study of surface roughness between several finishing and polishing procedures on ormocer-based composite resin and nanohybrid composite resin (복합 레진에서 마무리 방법에 따른 표면 거칠기 비교)

  • Jeong, Suk-In;Oh, Nam-Sik;Lee, Myung-Hyeon;Lee, En-Jung;Cho, Jung-Hyeon;Ji, Sung-Won
    • The Journal of Korean Academy of Prosthodontics
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    • v.46 no.2
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    • pp.105-115
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    • 2008
  • Statement of problem: Proper finishing and polishing enhance both the esthetics and the longevity of restored teeth. Blade finishing technique would be suited for smoothing and finishing. Evaluation of this technique are necessary. Purpose: The purpose of this study was to evaluate the blade finishing and polishing procedures on the surface profile and roughness of ormocer-based composite resin and nanohybrid composite resin. Material and methods: The material included a ormocer-based composite resin ($Admira^{(R)}$ & $Admira^{(R)}$ Flow); a nanohybrid composite resin ($Grandio^{(R)}$ & $Grandio^{(R)}$ Flow). One hundred forty specimens of each group were prepared using a mylar strip and randomly divied into blade finishing and rubber polishing groups (n=10). The average surface roughness (Ra) in micrometers was measured and the surface profile was examined by scanning electron microscopy (SEM) (Magnification ${\times}$ 200). The data were analyzed by Mann-Whitney Test at 0.05 significance level. Conclusion: The results of this study indicated that the mylar strip produced the smoothest surface on all materials and among the finishing-polishing methods was not significanct difference (P>0.05). Ormocer-based flowable composite resin performedthe lowest variability in initial surface roughness among the tested materials.

Signs and symptoms of temporomandibular disorders in instrumental performers (악기연주자의 측두하악장애 징후와 증상)

  • Jang, Jae-Young;Choi, Young-Chan;Bae, Jung-Hee;Kim, Seong-Taek
    • Journal of Dental Rehabilitation and Applied Science
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    • v.31 no.2
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    • pp.86-95
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    • 2015
  • Purpose: The aim of the study was to evaluate the subjective symptoms and clinical signs through the TMD-questionnaire, clinical examination and radiography against the many instrumental performers and to investigate the association between playing instruments and TMDs. Materials and Methods: A total of 803 instrumental performers received TMD-related questionnaire and evaluations of prevalence and disease distribution were performed. Among those who reported at least one symptom of TMD, 70 volunteers visited in clinic then received clinical examination and radiography for diagnosis and evaluations of prevalence and disease distribution were performed. 70 subjects were divided into three groups as woodwind, brass wind, string. Comparative analysis of disease distribution was performed. Results: Among 803 instrumental performers, 610 people (75.97%) were reported to one or more symptoms of TMD. The most frequent symptom was click (29.68%).70 subjects underwent a clinical examination and radiography survey results, the most frequent symptom was a click (29.75%). Most commonly diagnosed disease was a myofacial pain (30.53%).Comparison of the three groups, a significant difference was not observed in the clinical sign. But among subject symptom, muscle pains howed significant differences in accordance with the Group (P = 0.024). During the 70 people who underwent clinical examination, 66 people (94.3%) showed moderate to severe attrition, mild to severe tongue ridging, mild to severe cheek ridging assigns of parafunction. Conclusion: Instrumental performers showed a high prevalence of TMD and the most of the musicians with temporomandibular disorder had bruxism or clenching habits.

A Study on the Essence and Tendency of Modern Manager (현대 경영자로서의 본질과 성향 연구)

  • Yeom, Bae-Hoon;Kim, Hyunsoo
    • Journal of Service Research and Studies
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    • v.10 no.3
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    • pp.23-42
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    • 2020
  • This study conceptualized the essence and propensity of modern management in service age, based on philosophy, and developed items to evaluate the conceptualized content. It was carried out as a new study to deepen the study of management philosophy and management theory by the new management framework. In order to establish the philosophical foundation of the modern management, the essence of the modern management was conceptualized based on the fundamental ideas of the East and West, and then an evaluation item was developed to put the essence and propensity of the modern management into practical use through analytical and empirical methods. After analyzing the representative ideas of mankind, it was derived that the Book of Change has the qualification as a philosophical model that can derive the essence of modern management. The Book of Change explains the reasoning of the world in the structure of two opposing parties, such as Taiji or Yin and Yang, and the process of acknowledging the contradictions within each opposing party and overcoming the contradictions through change is the central idea. Because you can see. After conducting a conceptual study, through empirical research, the essence and propensity of a modern manager should be conceptualized. The concept of essence and empirical study of the modern management using the leading role was conducted in two stages. First, a qualitative study using repetitive comparative analysis (CCM), focus group interview (FGI), and text mining was conducted to derive the essential and propensity conceptualization items that modern managers should possess. In addition, a quantitative study using factor analysis to develop sample items and develop measurement items through literature review and FGI was conducted to derive the essential concept of the modern management. Finally, the essence of modern management was derived: learning, preparation, challenge, inclusion, trust, morality, and sacrifice. In the future, it is necessary to conduct empirical research on the effectiveness of the essence of modern management for global and Korean representative companies.

A comparative study between Korea and the USA on the development process in retail trade & its changing locations (소매업의 발달과정과 입지 변화에 관한 한.미 비교 연구)

  • Jeon, Kyung-Sook
    • Journal of the Korean association of regional geographers
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    • v.6 no.2
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    • pp.21-40
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    • 2000
  • The retail trades in many countries have changed recently according to the high quality, diversification, and marked individuality of consumer needs. Under the continually competing system of the WTO agreement, corporations based in the USA and the EU try to raise their market share in other countries so it is inevitable for Korean retail enterprises to compete with them. This paper is aimed at contributing to the efficient growth for Korean retail trade from the analysis of the development process in retail trade and its changing locations comparing Korea and the USA. Retailers in the USA have practiced diversified marketing strategies considerably in order to survive in a rapidly changing retailing environment. American retailing, which has the most advanced marketing system in the world, has been of growing concern to marketing strategies in Korea. The following is a brief summary of this study. 1. Speedy and higher quality consumption is needed in accordance with the great increase in the single-family household and the female labor force participation both in Korea and in the USA. Senior citizens have become a new consumer group due to the aging population. In the future the retail trade will switch over to diversified retail formats and internet shopping as countries are transformed into information and communication societies. 2. In Korea, the former retail system characterized by markets and department stores has been greatly changed since the late 1980s with emphasis on high quality and convenience in consumption behaviors, with large domestic enterprises and foreign distribution corporations participating in Korean retailing. In the USA, retailing mergers and takeovers by major retails, bankruptcies, and extra-large shopping centers have emerged since the late 1980s. Recently, the USA retailing formats have been changed from the lower price-oriented discount types to the large scale theme parks. Much emphasis was put on entertainment, resorts, and convention centers. On the other hand, non-store types, such as the internet shopping, the CATV shopping, as well as catalog and mail-order sales are drastically increasing, although the proportion of their sales is low up to now. 3. In Korea, most of the retail facilities are concentrated in Seoul and the Metropolitan Region, and the distribution ratio of facilities came to 52% in 1997. The periodic markets, traditional markets which open on a periodic basis, are located mainly in Chollanam-do and Kyungsangbuk-do. The large-sized discount stores have expanded their locations to the over-crowded apartment complexes in new towns, located in the Metropolitan Region, and the large provincial cities, unlike the suburban locations in the USA. Therefore we needed to give attention to the locational relations in retail facilities between Seoul & the Metropolitan Region and rural settlement areas. In the USA, urban areas grew quickly with the development of the automobile in the 1920s, and the location of stores changed from a dispersed style centering around rural areas to a centralized one in urban areas. There is an accelerated growth for suburban areas, which have grown rapidly since 1950. As the membership warehouse clubs were introduced in the 1970s, the decentralization of location was more intensified. On the other hand, inner cities were revitalized by rearranging existing facilities to cope with suburban areas. And the location-free virtual retailing & TV shopping are also growing every year. 4. In view of the above, the continuous and desirable development devices in Korean retail trade are summarized as follows: First, the countermeasures against economies of scale, increase in retailing sales, and rise of a employment percentage in retailing are in need. Second, a scheme of lowering the proportion of food retail sales, and increasing a ratio of durable goods sales need to be worked out. Third, the original ideas are needed to apply positively information, communication and technology to retailing, to graft the traditional types on modem ones based on the social culture. Fourth, strategies are needed to strengthen the competitiveness of our retail trade through cooperation and chains of smaller retailers, the large enterprises participating in the distribution industry. Fifth, in order to realize the above, the retail industry, the administration, and the academic world should support the retail segment with concern and a practical strategy plan.

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Direct foreign investment Korean firms:The case of Samsung Group (한국 기업의 해외직접투자:삼성그룹을 사례로)

  • Lee, Deog-An
    • Journal of the Korean Geographical Society
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    • v.28 no.4
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    • pp.379-391
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    • 1993
  • Present-day world economy is characterized by : technology nationalism, economic regionalism, market protectionism, multinational corporations, efc. All nations are striving for intensifying national economic rivalry and seeking after their own interests above everything else. Many regions of the world are also forming trading blocs, which could negatively affect nonmember states. The ultimate way to meet these difficulties is to establish production facilities in the countries imposing trade regulations. However, as the existing models of direct forrign investment (DFI) do not account for the particular nature of Korean firm's DFI activities, a new point of departure is imperative. It is because of this that Korean firms have only limited firm-specific advantages, the basic precondition of extant DFI theories, compared with their developed counterparts.

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Comparative Study of Cyclioxygenase-2 Expression and HER-2/neu Amplification in Korean and Caucasian Women with Early-Onset Breast Carcinoma (한국인과 백인 젊은 여성 유방암 환자에서 Cyclooxygenase-2 발현과 HER-2/neu 증폭의 비교 연구)

  • Choi, Doo-Ho;Kim, Eun-Seog;Kim, Yong-Ho;Jin, So-Young;Lee, Dong-Wha;Haffty, Bruce G.
    • Radiation Oncology Journal
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    • v.22 no.4
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    • pp.307-315
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    • 2004
  • Purpose: The purpose of this work was to study the differences of cyclooxygenase (COX-2) expression between Korean and Caucasian patients with early-onset breast carcinoma by immunohistochemistry. The test were analyzed to find a correlation between COX-2 and other biomarkers including HER-2/neu amplification, because we previously reported that a significant difference had been found in the expression of HER-2/neu between the two races. Furthermore, we investigated prognostic significance of COX-2 in korean patients. Materials and Methods: Sixty Korean women who were diagnosed breast carcinoma at 45 years old or younger and 60 Caucasian women with breast carcinoma were selected for this study. The median age of both groups was 37 years and tumor sizes were distributed evenly between the two group. Paraffin embedded blocks of primary tumor were processed for immunohistochemical staining of COX-2. The COX-2 expression was evaluated according to the percentage of positive cells and the intensity of staining. And the results were compared with the data of the previous studies to find correlation between COX-2 and other parameters and survival data. Results: Proportion of the COX-2 expression in total patients was $27.6\%$. The percentage of tumors that stained positive for COX-2 in korean and Caucasian women with early-onset breast carcinoma were $37.9\%$ and $20.8\%$, respectively. The difference was statistically not significant(p=0.090). Expression of COX-2 was not associated with several clinicopathologic parameters including HER-2/neu overexpression, but negative estrogen receptor status was correlated with significance (p=0.046). The 5 year disease free survival rate for patients with COX-2 expression was $67.9\%$, compared to $81.9\%$ of the COX-2 negative patients and the result was statistically not significant. Conclusions : A significant difference was not found in the expression of COX-2 between the two groups of patients with early-onset breast carcinoma. And correlation between COX-2 and other parameters was not observed except estrogen receptor negativity. Large scaled further research including radiotherapy factors will be needed to identify COX-2 as a prognostic role in patients with early-onset breast carcinoma.

Comparative Compressional Behavior of Zeolite-W in Different Pressure-transmitting Media (제올라이트-W의 압력전달매개체에 따른 체적탄성률 비교 연구)

  • Seoung, Donghoon;Kim, Hyeonsu;Kim, Pyosang;Lee, Yongmoon
    • Korean Journal of Mineralogy and Petrology
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    • v.34 no.3
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    • pp.169-176
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    • 2021
  • This study aimed to fundamentally understand structural changes of zeolite under pressure and in the presence of different pressure-transmitting media (PTM) for application studies such as immobilization of heavy metal cation or CO2 storage using pressure. High-pressure X-ray powder diffraction study was conducted on the zeolite-W (K6.4Al6.5Si25.8O64× 15.3H2O, K-MER) to understand linear compressibility and the bulk moduli in different PTM conditions. Zeolite-w is a synthetic material having the same framework as natural zeolite merlinoite ((K, Ca0.5, Ba0.5, Na)10 Al10Si22O64× 22H2O). The space group of the sample was identified as I4/mmm belonging to the tetragonal crystal system. Water, carbon dioxide, and silicone-oil were used as pressure-transmitting media. The mixture of sample and each PTM was mounted in a diamond anvil cell (DAC) and then pressurized up to 3 GPa with an increment of ca. 0.5 GPa. Pressure-induced changes of powder diffraction patterns were measured using a synchrotron X-ray light source. Lattice constants, and bulk moduli were calculated using the Le-Bail method and the Birch-Murnaghan equation. In all PTM conditions, linear compressibility of c-axis (𝛽c) was 0.006(1) GPa-1 or 0.007(1) GPa-1. On the other hand, the linear compressibility of a(b)-axis (𝛽a) was 0.013(1) GPa-1 in silicone-oil run, which is twice more compressible than the a(b)-axis in water and carbon dioxide runs, 𝛽a = 0.006(1) GPa-1. The bulk moduli were measured as 50(3) GPa, 52(3) GPa, and 29(2) GPa in water, carbon dioxide, and silicone-oil run, respectively. The orthorhombicities of ac-plane in the water, and carbon dioxide runs were comparatively constant, near 0.350~0.353, whereas the value decreased abruptly in the silicone-oil run following formula, y = -0.005(1)x + 0.351(1) by non-penetrating pressure fluid condition.

Geo-educational Values of the Jebudo Geosite in the Hwaseong Geopark, Korea (화성 지질공원 제부도 지질명소의 지질교육적 가치)

  • Ha, Sujin;Chae, Yong-Un;Kang, Hee-Cheol;Kim, Jong-Sun;Park, Jeong-Woong;Shin, Seungwon;Lim, Hyoun Soo;Cho, Hyeongseong
    • Journal of the Korean earth science society
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    • v.42 no.3
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    • pp.311-324
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    • 2021
  • Recently, ten geosites have been considered in Hwaseong for endorsement as national geoparks, including the Jebudo, Gojeongri Dinosaur Egg Fossils, and Ueumdo geosites. The Jebudo geosite in the southern part of the Seoul metropolitan area has great potential for development as a new geoscience educational site because it has geological, geographical (landscape), and ecological significance. In this study, we described the geological characteristics through field surveys in the Jebudo geosite. We evaluated its potential as a geo-education site based on comparative analysis with other geosites in Hwaseong Geopark. In addition, we reviewed the practical effect of field education at geosites on the essential concepts and critical competence-oriented education emphasized in the current 2015 revised science curriculum. The Jebudo Geosite is geologically diverse, with various metamorphic rocks belonging to the Precambrian Seosan Group, such as quartzite, schist, and phyllite. Various geological structures, such as clastic dikes, faults, joints, foliation, and schistosity have also been recorded. Moreover, coastal geological features have been observed, including depositional landforms (gravel and sand beaches, dunes, and mudflats), sedimentary structures (ripples), erosional landforms (sea cliffs, sea caves, and sea stacks), and sea parting. The Jebudo geosite has considerable value as a new geo-education site with geological and geomorphological distinction from the Gojeongri Dinosaur Egg Fossils and Ueumdo geosites. The Jebudo geosite also has opportunities for geo-education and geo-tourism, such as mudflat experiences and infrastructures, such as coastal trails and viewing points. This geosite can help develop diverse geo-education programs that improve key competencies in the science curriculum, such as critical thinking, inquiry, and problem-solving. Furthermore, by conducting optimized geo-education focused on the characteristics of each geosite, the following can be established: (1) the expansion of learning space from school to geopark, (2) the improvement of understanding of specific content elements and linkage between essential concepts, and (3) the extension of the education scope throughout the earth system. There will be positive impacts on communication, participation, and lifelong learning skills through geopark education.

Manbojeonseo(萬寶全書) Geumdoron(琴道論) in the old scores of Joseon(朝鮮) (조선시대 고악보에 나타난 『만보전서(萬寶全書)』의 금도론(琴道論))

  • Choi, Sun-a
    • (The) Research of the performance art and culture
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    • no.20
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    • pp.251-307
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    • 2010
  • Manbojeonseo, a kind of an encyclopedia published several times in Ming Ch'ing dynasty, includes useful information for scholars and common people on daily lives. In 1720, Manbojeonseo was first introduced to Joseon(朝鮮) dynasty by the diplomatic corps visiting Ch'ing dynasty, and widely circulated in the society as an useful information magazine or an individual collection of reference book. Since Manbojeonseo includes the systematically-organized contents of Geumdoron(琴道論, a theory of a heptachord), it could provide a useful reference when the Geumdoron was inserted as the contents of old scores. For an instance, Obultan(五不彈), Tangeumsuji(彈琴須知), and Taeeumgibeop(太音紀法) recorded in Hangeumsinbo(韓琴新譜, 1724) clearly acknowledge Manbojeonseo as their common source. In this paper, the order and the contents of Geumdorons from four different Manbojeonseo are compared. At first, the comparative analysis of Manbojeonseo (1610) edited by Seo Giryong(徐企龍) and Manbojeonseo(1612) edited by Yu Jamyeong(劉子明) are carried out focusing on the contents of the Geumdoron, where both Manbojeonseos contain considerable amount of Geumdoron sections. The tables of the contents in both Manbojeonseos are composed of upper and lower levels classified into 4 large divisions for each. While the contents of the upper level is presumably older and focused more on the theory of the cardinal virtues, the contents of the lower one is relatively new and centered more on the skills for the real play of a heptachord(琴), the lyrics and the musical scores composed of Gamjabo(減字譜). Therefore, it could be said that the upper level is metaphysical while the lower level is physical. One of the differences between those two Manbojeonseos lies in the order and the terminology found in the large divisions. In the case of Manbojeonseo(1612), some terms in the large division represent and theoretically group the detailed descriptions in the small divisions such as 5 demands or 7 taboos in the play of the heptachord. In addition, a few lower divisions were newly added or revised in order to enhance the completeness of Geumhangmun(琴學門, study of a heptachord), and the detailed classification was revised and polished to improve the reasonableness. In Manbojeonseo(1614) composed by the same editor as Manbojeonseo(1610), the contents of the Geumdoron become much briefer than those of Manbojeonseo(1610) and Manbojeonseo(1612). In the case of Manbojeonseo(1739), a new type of the Geumdoron is included called Oeumjeongjobo(五音正操譜) while carrying a similarly brief section of the Geumdoron. Finally, the Geumdorons in Manbojeonseo and several old scores are comparatively analyzed. While the Geumbo(琴譜) owned by Gugagwon(國樂院) and Hangeumsinbo contains relatively old Geumdoron, Yuyeji(遊藝志) and Bangsanhanssigeumbo(芳山韓氏琴譜) adopt practical and relatively new Geumdorons different from the former old scores and similar to Manbojeonseo(1739) considering the order and the contents. In particular, the contents of the Geumdoron in Geumheonakbo(琴軒樂譜) is notably unique containing much of the upper and the lower levels of Manbojeonseo(1612), therefore thought to have actively adopted the contents of new Geumdorons.

A Study of Jeongjae Performed by the Iwangjikaakbu(Royal Music Institute): Based on the mubo(choreography notes) of Lee Byungseong and Sung Gyeonglin (이왕직아악부의 정재 음악 연구 - 이병성·성경린 무보를 중심으로 -)

  • Lee, Jongsook
    • (The) Research of the performance art and culture
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    • no.34
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    • pp.173-214
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    • 2017
  • This study examines and compares music-related records in the mubo (舞譜; choreography notes) written by Sung Gyeonglin (成慶麟, 1911 - 2008), based on the records of 11 kinds of jeongjae (the music and dance performances at the royal court) found in Lee Byungseong's (李丙星, 1909 - 1960) Changsa and Jungjaecheol (呈才及唱詞綴). Even though these records are personal, they provide valuable information about the mubo of the Iwangjikaakbu (the Royal Music Institute) during the period of Japanese colonization. The eleven kinds types of jeongjae-'Cheoyongmu (處容舞)', 'Hyangryungmu (響鈴舞)', 'Mugo (舞鼓)', 'Bosangmu (寶相舞)', 'Chunangjeon (春鶯?)', 'Gainjeonmokdan (佳人剪牧丹)', 'Suyeonjang (壽延長)', 'Mansumu (萬壽舞)', 'Bongraeeui (鳳來儀)', 'Jangsaengboyeonjimu (長生寶宴之舞)', and 'Musanhyang (舞山香)'-can be largely divided into two types: Dangak (Tang dynasty music) and 'Hyangak (traditional Korean music).' The former is distinguished musically by whether or not the jukganja appears. For the appearance of the jukganja in 'Sujeyongjang', 'Bongraeeui' and 'Jangsaengboyeongjimu', the 'boheojaryung (步虛子令)' was used and given the impressive name of jangchunbullojigok (長春不老之曲).' The term punggyungjigok (豊慶之曲)' was used for music that guides a group dance and dancers. For the latter, hamnyungjigok (咸寧之曲) was performed during the development of the dance, and the pungungyeonghoijigok (風雲慶會之曲) was played at the end of the piece. As for the accompaniment for the jeongjae performed by the Iwangjikaakbu, it is significant that various elaborate names were attached to Sangryungsan, Jungryungsan, Seryungsanm, Garakdeoli, Samhyunhwanip, Yeombulhwanip, and taryung (the traditional Korean ballad), which were all parts of 'Samhyunyoungsanhoesang (靈山會上).' Specifically, the 'Hyangdanggyoju (鄕唐交奏)' in 'Jeongjaemudoholgi' was accompanied by various melodies of the 'Samhyunyoungsanhoesang', which were given extravagant names. These are the personal records of the Iwangjikaakbu mubo that were retained by Lee Honggu (李興九, b. 1940), who owns the 'Hakyeonhwadaehapseolmu.' Among them, the ten kinds of jeongjae found in the notes of Sung Gyeonglin are often referred to as 'mueui (舞儀)' and widely used for research on individual jeongjae performances and the history of their development. The notes of Lee Byungseong have not been investigated thoroughly until now and this is the first study that provides a comparative analysis of the notes of Lee Byungseong and Sung Gyeonglin. This investigation is expected to contribute to the further research and knowledge of the jeongjae performance during the period of Japanese colonization.