• The Journal of Korean Academy of Prosthodontics
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• v.49 no.2
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• pp.168-176
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• 2011

Purpose: This study aims at investigating the influence of various insertion torques on thermal changes of bone. A proper insertion torque is derived based on the thermal analysis with two different implant designs. Materials and methods: For implant materials, bovine scapula bone of 15 - 20 mm thickness was cut into 35 mm by 40 - 50 mm pieces. Of these, the pieces having 2 - 3 mm thickness cortical bone were used as samples. Then, the half of the sample was immersed in a bath of $36.5^{\circ}C$ and the other half was exposed to ambient temperature of $25^{\circ}C$, so that the inner and surface temperatures reached $36.5^{\circ}C$ and $28^{\circ}C$, respectively. Two types of implants ($4.5{\times}10\;mm$ Br${\aa}$nemark type, $4.8{\times}10\;mm$ Microthread type) were inserted into bovine scapula bone and the temperature was measured by a thermocouple at 0.2 mm from the measuring point. Finite element method (FEM) was used to analyze the thermal changes at contacting surface assuming that the sample is a cube of $4\;cm{\times}4\;cm{\times}2\;cm$ and a layer up to 2 mm from the top is cortical bone and below is a cancellous bone. Boundary conditions were set on the basis of the shape of cavity after implants. SolidWorks was used as a CAD program with the help of Abaqus 6.9-1. Results: In the in-vitro experiment, the Microhead type implant gives a higher maximum temperature than that of the Br${\aa}$nemark type, which is attributed to high frictional heat that is associated with the implant shape. In both types, an Eriksson threshold was observed at torques of 50 Ncm (Br${\aa}$nemark) and 35 Ncm (Microthread type), respectively. Based on these findings, the Microthread type implant is more affected by insertion torques. Conclusion: This study demonstrate that a proper choice of insertion torque is important when using a specific type of implant. In particular, for the Microthread type implant, possible bone damage may be expected as a result of frictional heat, which compensates for initial high success rate of fixation. Therefore, the insertion torque should be adjusted for each implant design. Furthermore, the operation skills should be carefully chosen for each implant type and insertion torque.

• Korean Journal of Remote Sensing
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• v.33 no.5_1
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• pp.469-480
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• 2017

This study aims to understand the relationship between lineaments and epicenters in Geochang region, Gyungsangnam-do, South Korea. An instrumental observation of earthquakes has been started by Korea Meteorological Administration (KMA) since 1978 and there were 6 earthquakes with magnitude ranging 2 to 2.5 in Geochang region from 1978 to 2016. Lineaments were extracted from LANDSAT 8 satellite image and shaded relief map displayed in 3-dimension using Digital Elevation Model (DEM). Then, lineament density was statistically examined by hotspot analysis. Hexagonal grids were generated to perform the analysis because hexagonal pattern expresses lineaments with less discontinuity than square girds, and the size of the grid was selected to minimize a variance of lineament density. Since hotspot analysis measures the extent of clustering with Z score, Z scores computed with lineaments' frequency ($L_f$), length ($L_d$), and intersection ($L_t$) were used to find lineament clusters in the density map. Furthermore, the Z scores were extracted from the epicenters and examined to see the relevance of each density elements to epicenters. As a result, 15 among 18 densities,recorded as 3 elements in 6 epicenters, were higher than 1.65 which is 95% of the standard normal distribution. This indicates that epicenters coincide with high density area. Especially, $L_f$ and $L_t$ had a significant relationship with epicenter, being located in upper 95% of the standard normal distribution, except for one epicenter in $L_t$. This study can be used to identify potential seismic zones by improving the accuracy of expressing lineaments' spatial distribution and analyzing relationship between lineament density and epicenter. However, additional studies in wider study area with more epicenters are recommended to promote the results.

• The Korean Journal of Nuclear Medicine
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• v.38 no.1
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• pp.74-84
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• 2004

Purpose: Since I-125 emits low energy (27-35 keV) radiation, thinner crystal and collimator could be employed and, hence, it is favorable to obtain high quality images. The purpose of this study was to derive the optimized parameters of I-125 SPECT using a new simulation tool, GATE (Geant4 Application for Tomographic Emission). Materials and Methods: To validate the simulation method, gamma camera developed by Weisenberger et al. was modeled. Nal(T1) plate crystal was used and its thickness was determined by calculating detection efficiency. Spatial resolution and sensitivity curves were estimated by changing variable parameters for parallel-hole and pinhole collimator. Peformances of I-125 SPECT equipped with the optimal collimator were also estimated. Results: in the validation study, simulations were found to agree well with experimental measurements in spatial resolution (4%) and sensitivity (3%). In order to acquire 98% gamma ray detection efficiency, Nal(T1) thickness was determined to be 1 mm. Hole diameter (mm), length (mm) and shape were chosen to be 0.2:5:square and 0.5:10:hexagonal for high resolution (HR) and general purpose (GP) parallel-hole collimator, respectively. Hole diameter, channel height and acceptance angle of pinhole (PH) collimator were determined to be 0.25 mm, 0.1 mm and 90 degree. The spatial resolutions of reconstructed image of the I-125 SPECT employing HR:GP:PH were 1.2:1.7:0.8 mm. The sensitivities of HR:GP:PH were 39.7:71.9:5.5 cps/MBq. Conclusion: The optimal crystal and collimator parameters for I-125 Imaging were derived by simulation using GATE. The results indicate that excellent resolution and sensitivity imaging is feasible using I-125 SPECT.

• (The) Research of the performance art and culture
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• no.39
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• pp.701-748
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• 2019

Gwanak-yeongsanhoesang, called as Samhyeon-yeongsanhoesang or Pyojeongmanbangjigok, is played by the musical instrumental organization, Samhyeonyukgak or by a large scale wind ensemble added Sogeum and Ajaeng. This study aims to analyze the structure and form of Piri melody which plays major melody of Sangnyeongsan in Gwanak-yeongsanhoesang, and to examine the relationship between Piri melody and Daegeum yeoneum grasping the structure and function of yeoneum. In Sangnyeongsan of Gwanak-yeongsanhoesang, the criterion for grouping the phrases of Piri melody is yeoneum. Especially, Daegeum yeoneum carries out the function of finishing the phrase of Piri playing the major melody by ornamenting or extending it, and presenting the motives or motive elements of the next phrase while Piri rests. The types of a, b, g, and i in the various shapes of the minimum melodic fragment of Piri are important motive elements that constitute a phrase of Piri melody. Especially, main motive a-type (仲→無) contrasts with b type (林→潢) which forms a strong tension by transposing 2 degrees upward. In addition, a-type gradually descends towards the end of music by changing to g-type (仲→林) or to i-type (太→林) which is 3 degrees below, which is related to the gradual descent cadence of Korean traditional music. A phrase of Piri melody of Sangnyeongsan in Gwanak-yeongsanhoesang consists of a combination of the types a, b, g, i, and cadence (x-type), and each phrase is structured in the repeating tension-relaxation. Looking at the structure of Piri phrases by similar types, each phrase has a logical variation structure through the methods such as omission and addition of notes, and crossing of melodies. The shape of the minimum melodic fragment of Daegeum yeoneum can be divided into a back-yeoneum of a~b types and a front-yeoneum of x1~x3. The x-types ornament Jungnyeo (仲), the cadence tone of Piri melody or are simply used as the extending back-yeoneum, and types a and b have the function of a front-yeoneum that prepares the beginning of the next phrase of Piri melody. The combination types of the minimum melodic fragment of Daegeum yeoneum appear mostly as the shape of back-yeoneum + front-yeoneum. In addition, the front-yeoneum of the type a and b appears independently without back-yeoneum, and the x3 type has a shape of the back-yeoneum without the front-yeoneum. Looking at the structure of Daegeum yeoneum by similar types, it can be seen that Daegeum yeoneum is also composed of a variation structure of omission and addition of notes like Piri melody.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.33 no.4
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• pp.26-37
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• 2015

This paper aims to review all landscaping elements of Donggwoldo by building and identify the palatial garden landscaping characteristics and landscaping methods in a bid to explore landscaping methods applicable for modern-time gardens of Korea through Succession of Tradition. The research methodology was adopted by which the palatial gardens appearing in Donggwoldo were observed according to garden elements to identify their characteristics. Garden elements in Donggwoldo include oddly shaped stones, ponds, buildings and Madang, borders and areas, and trees. Their characteristics were analyzed, and as a result they are outlined as follows. Location : Buildings in Donggwoldo were located in the optimal areas within the Myungdang (the best location), with the building sites being created by transforming the natural topography positively according to the existing topography and uses. Tree planting : The construction of the buildings involved using the existing trees. There were no specific principle and method of planting trees, and no specific criteria for choosing the kind of tree. Symmetrical planting was adopted and its is considered embracing the viewpoint of making gardens based on the expression of Yin and Yang. Strongly symbolical kinds of trees were also adopted. Bangji : it takes a nearly circular shape in palatial gardens, and such shapes represent conceptual and abstract symbols. They were also frequently used as the place of public entertainment. Pavilions : they did not take a certain standard shape. They had diverse shapes, including a triangle, square, pentagon, hexagon, and octagon and cross. Oddly shaped stones : Oddly shapes stones and stone cases were deployed mainly near the bedroom and the crow prince's residence and in the rear garden. Hwagye : it appeared mainly in the back of the bedroom, the crown prince's residence, the princess's residence, and other women's quarters. Chwibyeong : it was installed for the purpose of drawing the natural energy like a natural inlet instead of being the nature-dividing wall. Korea's garden composition method was very different from the Western and Chinese method. Overall, Chosun palatial garden style was characterized by strict and Confucian features, while the garden construction method adopted the Taoism thought. Yet, the gardens had a carefree aspect.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.32 no.1
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• pp.31-43
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• 2014

The purposes for this research were to find the correct building background of Jondeokjeong(尊德亭) in the rear garden of Changdeok Palace(昌德宮) based on the historical facts for the area of Jondeokjeong and investigate the internal theory of construction through the metaphysical consideration. The results were as follows. 1. Building background of Jondeokjeong was related to Sohyunseja(昭顯世子) and Bongrimdaegun(鳳林大君) as forms of rear garden where was not built in the area of Jondeokjeong, bamboo pavilion, hexagonal pavilion, octagonal pavilion, etc. They were built two or three times after returning of Sohyunseja and Bongrimdaegun from China, and the area of Jondeokjeong was continuously developed by building Chunhyanggak(天香閣), Mangchunjeong(望春亭) and Cheoknoidang(滌惱堂) after Hyojong(孝宗) succeeded the royal authority of Hyunjong(顯宗) who was born in Shenyang(瀋陽) and hung a signboard of Jondeokjeong after then, etc. 2. Dazhengjeon(大政殿) of Shenyang Palace(瀋陽故宮, 1625) played the roles of major hall, Jeongjeon(正殿) which held national big events as a one-storied building with two piles of roof similar with Jondeokjeong (1644). Also, it was the building encountered when Sohyunseja and Bongrimdaegun participated in breakfasts held in the palace or banquets supervised by a king, so building background of Jondeokjeong was judged to be related with Dazhengjeon. 3. In consideration of characteristics which are shown commonly in Jondeokjeong and Dazhengjeon, relations of two buildings were verified and characteristics of Jondeokjeong were examined. First, dragon which is representatively symbolizing royal authority was formed. Therefore, Jondeokjeong was judged as a garden building which purposes were to obtain and train natural reasons, govern the nation and let people comfortable. Second, the purposes of sun dial, Ilyoungdae(日影臺) were judged to examine the accurate time and express appropriateness of the king. Third, Taechungmun(太淸門) around there is related to Samcheong(三淸) of Taoism and judged to be caused by floral wall and secular happiness accomplishment for king's longevity without disease. Fourth, for building style, one-stories pavilion of duplicated roof and building with only cylinder were to king's embodiment of supporting the sky and governing the nation.4) 4. By examining the differences between Jondeokjeong and Dazhengjeon, Jondeokjeong's own characteristics were considered. First, constructive characteristics of Jondeokjeong were changed by existing of pond and it was changed for characteristics, location and function of pavilion built in the garden while accepting oversea culture and embodied by absorbing to Joseon culture. Second, the appearance of the pond in Jondeokjeong was shown as the situation that half moon typed pond with the form of young moon is full by stream to the East. It was to express movement of moon which was always changed through the form of pond and stream of water iconographycally and it was considered as an imaginary environment method of the period.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.4
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• pp.424-434
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• 2009

Statement of problem: Problems such as loosening and fractures of retained screws and fracture of implant fixture have been frequently reported in implant prosthesis. Purpose: Implant has weak mechanical properties against lateral loading compared to vertical occlusal loading, and therefore, stress analysis of implant fixture depending on its material and geometric features is needed. Material and methods: Total 28 of external hexed implants were divided into 7 of 4 groups; Group A (3i, FULL $OSSEOTITE^{(R)}$Implant), Group B (Nobelbiocare, $Br{\aa}nemark$ $System^{(R)}$Mk III Groovy RP), Group C (Neobiotec, $SinusQuick^{TM}$ EB), Group D (Osstem, US-II). The type III gold alloy prostheses were fabricated using adequate UCLA gold abutments. Fixture, abutment screw, and abutment were connected and cross-sectioned vertically. Hardness test was conducted using MXT-$\alpha$. For fatigue fracture test, with MTS 810, the specimens were loaded to the extent of 60-600 N until fracture occurred. The fracture pattern of abutment screw and fixture was observed under scanning electron microscope. A comparative study of stress distribution and fracture area of abutment screw and fixture was carried out through finite element analysis Results: 1. In Vicker's hardness test of abutment screw, the highest value was measured in group A and lowest value was measured in group D. 2. In all implant groups, implant fixture fractures occurred mainly at the 3-4th fixture thread valley where tensile stress was concentrated. When the fatigue life was compared, significant difference was found between the group A, B, C and D (P<.05). 3. The fracture patterns of group B and group D showed complex failure type, a fracture behavior including transverse and longitudinal failure patterns in both fixture and abutment screw. In Group A and C, however, the transverse failure of fixture was only observed. 4. The finite element analysis infers that a fatigue crack started at the fixture surface. Conclusion: The maximum tensile stress was found in the implant fixture at the level of cortical bone. The fatigue fracture occurred when the dead space of implant fixture coincides with jig surface where the maximum tensile stress was generated. To increase implant durability, prevention of surrounding bone resorption is important. However, if the bone resorption progresses to the level of dead space, the frequency of implant fracture would increase. Thus, proper management is needed.

• (The) Research of the performance art and culture
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• no.36
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• pp.751-781
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• 2018

Task of circling the pagoda of Waljeongsa(Woljeongsa Tabdori) is the major intangible cultural heritage with representativeness and historical meaning as a Buddhism culture, one of the Buddhism folk plays, which was firstly played after the liberation. Woljeongsa Tabdori holds significant designation importance in terms of Buddhism folklore heritage with Korean unique tradition and identity of Gangwon-do province. Temples are demonstrating Tabdori nationwide but Woljeongsa Tabdori is the unique case that systematically inherits the culture based on the designation of being intangible cultural heritage. That is why it is needed to focus on the cultural and internal value of Woljeongsa Tabdori. Tabdori is the integrated symbol of Buddhism respect and worship to the Buddha and pagoda. It is hard to presume the originality of Woljeongsa Tabdori: given the history of Woljeonsa temple, it lies into Goguryeo traditional play and Bokhui(Pagoda circling folk play) in Silla era. It fits into the courtesy of Circumambulating Stupa considering Moon in Goguryo mural, background of Odaesan Hwaeom thought/tripitaka and essence of Octagonal 9-story stone pagoda. At the first stage of Tabdori, Buddhist musical instruments such as Buddhism temple bell, singing bowl, cloud-shaped gong and wooden-fish. However, later, Samhyeon Yukgak has been added and then, Boyeom and Bakpaljeongjinga were singing: it could be interpreted that it was a pure Buddhist ceremony but it has become to have traditional aspect and been spread to the public. The origin of Woljeongsa Tabdori is related to the explanation of Circumambulating Stupa that experiences the glory of the ending ceremony. When a temple has a rite, the Buddhists make an offering to the Buddha. At that time, Buddhist prayer, sermon and chant are followed. After the rite, the Buddhists are circling the pagoda with the monks while praying for Buddhist charity and making their own wishes. It prays not only going after death to Nirvana of the one but also national prosperity and the welfare of the people for peaceful reign. As the temple holds bigger rites, many Buddhists gather and the Tabdori was a success. The scene of circling the pagoda and making own wishes in line with the Buddhist sermon was solemn. The idea on changes and convergence of Woljeongsa Tabdori requires strategic inheritance to promote the transmission while maintaining the paragon and purpose of designating the cultural heritage and reviving its identity. Korean Tabdori was held in Buddha's birthday in April and the mid-autumn day. Tabdori is a memorial service type Buddhist ceremony that once the monk holds the Buddhist rosary, circles the pagoda and sings the great mind and charity of the Buddha, Buddhists follow the step, lighting the lantern, circling the pagoda and praying for the gentle and easy death. Transmission education of the successor, diversified approach of the expert's advice and discourse on the revival of the origin should be reinforced in phases.

• (The) Research of the performance art and culture
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• no.22
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• pp.287-325
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• 2011

This paper studies the time-space and appreciation of the performance culture of Gwanseo region, which is considered to have formed a characteristic culture in late Joseon period. For this purpose, 4 gasa written in hangeul (Korean alphabet), as well as 4 yeonhaeng gasa, 108 articles of Gwanseoakbu were examined. Plus, among the 9 types of yeonhaengrok (Documents of Performance culture) written in Chinese character, those parts which describe the performance traits have been analyzed. Then, 'main list of terminology' has been deduced based on the categorization according to the following points : 1) subjects of performance and appreciation 2) time and period of performance 3) space of performance 4) contents of performance 5) background and motive for performance and 6) method of performance. Through this process, various 'nouns' and 'predicate verbs' in relation to performance culture emerged, which were systemized according to types of performance elements and categories. Major terminology includes predicate verbs and symbolic verbs such as nokuihongsang,' 'baekdaehongjang,' 'jeolsaekgeumga,' 'cheonga,' 'hwaryu,' 'gamuja,' and 'tongsoja,' as well as the terms already known such as gisaeng, iwon, yangbang, akgong, and jeonak, which refer to musicians and dancers. Subjects of performance were divided into performers and listeners, categorized into concert, music, and dance, according to performance form. In the case for music, it was divided into instrumental or vocal, solo or accompanied (byeongju, self-accompaniment). In the case for vocal music, noteworthy was the inclusion of profesional artist's singing (called gwangdae or uchang). The record of 23 names of popular artists from Gwanseo region, with mention of special talents for each person, reflects the degree of activeness and artistic level of the province. Depending on the appreciating patrons, the audience were indicated as the terms including 'yugaek (party guest),' jwasang,' 'on jwaseok,' and 'sonnim (guests).' It seems that appraisal for a certain performance was very much affected by the tastes, views, and disposition of the appreciating patrons. Therefore it is interesting to observe different comparative reviews of concerts of different regions given by literary figures, offering various criticism on identical performance. In terms of performance space, it has been divided into natural or architectural space, doing justice to special performance sites such as a famous pavilion or an on-the-boat performance. Specific terms related to the scale and brightness of stage, as well as stage props and cast, based on descriptions of performance space were found. The performance space, including famous pavilions; Yeongwangjeong, Bubyeokru, Baeksangru, Wolparu, and Uigeomjeong, which are all well-known tourist sites of Gwanseo province, have been often visited by viceroys. governors, and envoys during a tour or trip. This, and the fact that full-scale performances were regularly held here, and that more than 15 different kinds of boats which were used for boat concert are mentioned, all confirm the general popularity of boat concerts at the time. Performance time, categorized by season or time of day (am/pm/night) and analyzed in terms of time of occurrence and duration, there were no special limitation as to when to have a performance. Most morning concerts were held as part of official duties for the envoys, after their meeting session, whereas evening concerts were more lengthy in duration, with a greater number of people in the audience. In the case of boat concert, samples include day-time concert and performances that began during the day and which lasted till later in the evening. Major terminology related to performance time and season includes descriptions of time of day (morning, evening, night) and mention of sunset, twilight, moonlight, stars, candles, and lamps. Such terms which reflect the flow of time contributed in making a concert more lively. Terminology for the contents of performance was mostly words like 'instrumental,' 'pungak,' or 'pungnyu.' Besides, contextual expressions gave hints as to whether there were dance, singing, ensemble, solo, and duets. Words for dance and singing used in Gwanseo province were almost identical to those used for gasa and jeongjae in the capital, Hanyang. However, many sentences reveal that performances of 'hangjangmu' of hongmunyeon, sword dance, and baettaragi were on a top-quality level. Moreover, chants in hanmun Chinese character and folk songs, which are characteristic for this region, show unique features of local musical performance. It is judged that understanding the purpose and background of a performance is important in grasping the foundation and continuity of local culture. Concerts were usually either related to official protocol for 'greeting,' 'sending-off,' 'reports,' and 'patrols' or for private enjoyment. The rituals for Gwanseo province characteristically features river crossing ceremony on the Daedong river, which has been closely documented by many. What is more, the Gwanseo region featured continued coming and goings of Pyeongan envoys and local officers, as well as ambassadors to and fro China, which required an organized and full-scale performance of music and dance. The method of performance varied from a large-scale, official ones, for which female entertainers and a great banquet in addition to musicians were required, to private gatherings that are more intimate. A performance may take the form of 'taking turns' or 'a competition,' reflecting the dynamic nature of the musical culture at the time. This study, which is deduction of terminology in relation to the time-space and appreciation culture of musical performances of Gwanseo region in late Joseon period, should be expanded in the future into research on 'the performance culture unique to Gwanseo region,' in relation to the financial and administrative aspects of the province, as well as everyday lifestyle. Furthermore, it could proceed to a more intensive research by a comparative study with related literary documents and pictorial data, which could serve as the foundation for understanding the use of space and stage, as well as the performance format characteristic to Korean traditional performing arts.