• Korean Journal of Heritage: History & Science
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• v.54 no.1
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• pp.280-301
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• 2021

Chogak has been regarded as originating from the paintings decorating building elements. Various curved shape drawings that were first seen in the paintings of Goguryeo tomb murals evolved into the vine patterned Dancheong of Geuklakjeon in Bongjeongsa. Cheomcha of Geuklakjeon was chiseled with Yeonhwadusik relievo at the bottom on top of Dancheong, and this was the beginning of Cheomcha-Chogak. Also, Cheomcha, which was carved with a preliminary vine patterned Chogak in Daeungjeon in Bongjeongsa, opened the era of engraving Chogak directly on the surface of structural elements. Since then, vine patterned Chogak was a significant decoration technique for the Cheomcha of traditional wooden construction for a long time. Because Jeongjagak is a structure that was continuously built between the end of the Japanese invasion of Korea in 1592 and the late Joseon Dynasty, the transition of Cheomcha-Chogak over time can be seen through Jeongjagak architecture. The early Cheomcha-Chogak presents stems that climb up (Upbound-type) towards the headpiece on a column, while stems of Chogak later reversed direction to descend (Downbound-type) from the headpiece. This study examined the transition process and reasons for the change, with a focus on the findings above, and identified a new type of Chogak that is unrelated to the direction type and was adopted during the transition from Upbound-type to Downbound-type. The new type appeared when the Jeongjagaks for the Royal Tomb of Kyeongjo and those of the Injo were built, and it matches with the transitional period wherein lotus vanishes from Hwaban-Chogak. The study also inferred that the direction change of Cheomcha-Chogak stems was caused by the separation of vine patterned Chogak, carved with a two-stepped inner Ikgon, into both upward and downward from the headpiece, and this led to the changes that manifested as the inside of Choikgong being the Downbound-type Chogak and the variegated vine patterned Chogak of Choikgong affecting the direction of Cheomcha-Chogak. This is the follow-up study of "A Study on the Hwaban-Chogak of the Neungwon-Jeongjagak," a paper published in 2018, and is limited in n that Cheomcha, the focus of the research, is just one of the construction elements of Jeongjagak. The entirety ofChogak cannot be understood only by observing Cheomcha.

• Korean Journal of Heritage: History & Science
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• v.55 no.2
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• pp.252-271
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• 2022

This article examines the characteristics of the royal tombs of the late Silla Dynasty with the statues of the 12 animal deities(Zodiac) and estimates the process of change. The features of the statues show a difference in their combination in terms of continuity and similarity of the object in their hands. In addition, there is a difference in the shape of the face of the stone statue, and differences are observed in the orientation and aspect ratio of the statue according to the sculptural method. The characteristics of these statues are somewhat different from the previously studied protected-stone and manufacturing techniques. For example, the Zodiac statues that are flattened from high relief to low relief are known to be decorated in realistic expressions, but they tend to be treated as separate conditions because they do not match the change of the stone. In addition, there was a characteristic that did not show regular changes, such as appearing and disappearing again when there was no balustrade in the tomb. Summing up the characteristics of each part, the Zodiac statues are largely divided into curved angles and flat angles according to the sculptural technique, and the head orientation and clothing of the statue are related. They are divided into two categories and can be viewed as having temporality according to the aspect ratio. These characteristic changes are consistent with the continuity of features and changes in the object in the hands of the 12 Zodiac statues. Therefore, the number of faces with protected-stone changes were gradually increasing in trend. As a result, there is a possibility that the Gujeongdong Square-shape Tomb and King Jindeok Tomb are earlier royal tombs than the Wonseong Royal Tomb. Therefore, the royal tombs of the late Silla Dynasty have a complete, tomb structure, containing the 12 animal god statues, ceremonial spaces(拜禮空間), Shindo(神道), stone statues(石像), and tombstones. This can be understood as a basic motif for the royal tomb structures of Goryeo and Joseon.

• Korean Journal of Heritage: History & Science
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• v.55 no.3
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• pp.102-118
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• 2022

Gyeongju, the capital of Silla, is the very essence of the culture and technology of the thousand-year-reign of Silla. However, few studies have been conducted on the landscape sites of the capital of Silla other than Donggung Palace and Wolji Pond, due to the lack of related data. Therefore, this study examined the construction characteristics and nature of the garden pond in Guhwang-dong, whose complete appearance was identified through excavation following Donggung Palace and Wolji Pond. Since the excavation of the garden pond in Guhwang-dong, Gyeongju, there have been disagreements in academia as to whether it is a palace pond or a temple pond of Bunhwangsa Temple. Considering the unique characteristic of the garden pond that it is divided into two periods, it was interpreted that it would have functioned as a ritual facility related to Ryong (oriental dragon) belief in the 6th to 7th centuries, the first period, and as a garden pond with enhanced landscaping functions in the 8th to 9th centuries, the second period. In addition, it is highly probable that it was the site of Cheongyeongung Palace (青淵宮) and Jochujeong Pavilion (造秋亭) mentioned in the literature records. The "ㄹ"- shaped waterway, a characteristic facility of the first period, was found; however, considering its width and depth, it is insufficient to conclude that it was a simple drainage facility. Rather, it is more likely that it functioned as a passageway for the conceptual entry of Ryong during Ryong rituals. Furthermore, some have suggested that it may have been a ceremony-related Yusang-goksu (流觴曲水) facility. These facilities related to Ryong rituals were reorganized in the second period. Specifically, the nature of the garden pond was changed centered on the landscaping function in connection with the addition of a curved revetment, garden stone, and pavilion buildings, and the dismantlement of the "ㄹ"-shaped waterway and hexagonal building. As for nature, it can be regarded as a royal facility in terms of decorative elements including the ritual function of the first period and the gwimyeonwa (ghost face tiles) of the second period. Judging from the fact that the upper part of the embankment adjacent to the west side of the site was removed, it is very apparent that the main building was located on the upper part of the embankment. There would not have been a large-scale building site because it served the functions of ritual and recreation, rather than being the residence of the king.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.4
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• pp.437-448
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• 2021

The purpose of this study is to analyze morphological characteristics of maxillary primary molar's root and root canal. 268 children aged 3 - 7 years (175 boys, 93 girls) who had CBCT (152 children) and 3D CT (116 children) taken in Seoul National University Dental Hospital from January 2006 to April 2020 were included. The number of roots and root canals were analyzed in 1002 teeth without any root resorption or periapical pathologies. Curvature, angulation, length of root and root canal, as well as cross-sectional shapes of the root canal were analyzed in 218 teeth. By using Mimics and 3-Matics software, volume, surface area, and volume ratio of root canal was analyzed in 48 teeth. More than half of maxillary primary molars have 3 roots and 3 root canals. The degree of symmetry of root canal type was about 0.63 (Cohen's kappa coefficient). The most frequent shape of roots and canals was linear in 1^st primary molars and curved in 2^nd primary molars. Angulation, length of root and root canals was the largest on palatal roots. Most teeth showed ovoid or round shapes at apex. The largest root canal volume, surface area, volume ratio was found in the palatal roots.

• (The) Research of the performance art and culture
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• no.42
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• pp.147-181
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• 2021

Dalgubal drum dance is inherited in a recreated form by incorporating regional symbolism and the dance philosophy and artisticity of Young Hwangbo, the creator, based on the traditional drum dance of the Yeongnam region. This dance having popularity with the transformation of traditional Korean culture has been invited not only to Yeongnam region including Daegu but also to international various venues. This study explores what the movement characteristics of this Dalgubal drum dance are and the unique charm and symbolic meaning of this dance. Specific analysis was conducted through analyzing Dalgubal drum dance video film of the 89th Korean Myeongmujeon's by using Laban Movement Analysis as a research method. The special features of this dance resulted from the LMA analysis in terms of the four categories-Body, Effort, Shape, and Space-reveal simple yet cheerful personalities and strong yet patient characteristics of the people in Daegu. The harmony of drum sounds(music) and movements(dance) creates various characteristics of dances and reveals the beauty and excitement of unique Korean dance. In particular, drum play and its related dance movements create curved linear spatial pattern of arm movements, Spiral Shape in body posture, and diverse floor patterns occupying whole stage space. These movements show the three-dimensional spatial beauty and the artistic ideas for recreation of traditional drum dance, which considered with the spatial structure of the proscenium stage. In addition, the well-organized structure and harmonious movements of this dance show the traditional Korean philosophy, implying heaven, earth, and human being and the wholeness, and the harmony of yin and yang. The dance aims at communication between the audiences and dancers through sharing excitement and the aesthetic beauty of dance. This can be interpreted as a meaningful expression of traditional Korean philosophy developed with the unique value and characteristics of Korean dance.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.5A
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• pp.407-415
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• 2010

In Korea, more than 90% of the total number of steel bridges built for 40~70 m span length is a steel box-girder bridge type. A steel box-girder bridge is suitable for long span or curved bridges with outstanding flexural and torsional rigidity as well as good constructability and safety. However, a steel box-girder bridge is uneconomical, requiring many secondary members and workmanship such as stiffeners and ribs requiring welding attachments to flanges or webs. Therefore, in US and Japan, a plate girder bridge, which is relatively cheap and easy to construct is generally used. One type of the plate girder bridge is the two- or three-main girder plate bridge, which is a composite plate girder bridge that minimizes the number of required main girders by increasing the distance between the adjacent girders. Also, for the simplification of girder section, the stiffener which requires attachment to the web is not required. The two-main steel girder plate bridge is a representative type of plate girder bridges, which is suitable for bridges with 10 m effective width and has been developed in the early 1960s in France. To ensure greater safety of two- or three-main girder plate bridges, a larger steel section is used in the bridge domestically than in Europe or Japan. Also, the total number of two- or three-main girder plate bridge constructed in Korea is significantly less than the steel box girder bridge due to a lack of designers' familiarity with more complex design detailing of the bridge compare to that of a steel box girder bridge design. In this study, a new construction method called Turn Over method is proposed to minimize the steel section size used in a two- or three-main girder plate bridge by applying prestressing force to the member using confining concrete section's weight to reduce construction cost. Also, a full scale 20 m Turn Over girder specimen and a Turn Over girder bridge specimen were tested to evaluate constructability and structural safety of the members constructed using Turn Over process.

• Journal of Practical Engineering Education
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• v.15 no.1
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• pp.119-126
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• 2023

Today, in order to improve fuel efficiency and dynamic behavior of automobiles, an era of light weight and simplification of automobile parts is being formed. In order to simplify and design and manufacture the shape of the product, various components are integrated. For example, in order to commercialize three products into one product, product processing is occurring to a very narrow area. In the case of existing parts, precision die casting or casting production is used for processing convenience, and the multi-piece method requires a lot of processes and reduces the precision and strength of the parts. It is very advantageous to manufacture integrally to simplify the processing air and secure the strength of the parts, but if a deep and narrow pocket part needs to be processed, it cannot be processed with the equipment's own spindle. To solve a problem, research on cutting processing is being actively conducted, and multi-axis composite processing technology not only solves this problem. It has many advantages, such as being able to cut into composite shapes that have been difficult to flexibly cut through various processes with one machine tool so far. However, the reality is that expensive equipment increases manufacturing costs and lacks engineers who can operate the machine. In the five-axis cutting processing machine, when producing products with deep and narrow sections, the cycle time increases in product production due to the indirectness of tools, and many problems occur in processing. Therefore, dedicated machine tools and multi-axis composite machines should be used. Alternatively, an angle spindle may be used as a special tool capable of multi-axis composite machining of five or more axes in a three-axis machining center. Various and continuous studies are needed in areas such as processing vibration absorption, low heat generation and operational stability, excellent dimensional stability, and strength securing by using the angle spindle.

• The Journal of the Petrological Society of Korea
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• v.27 no.3
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• pp.109-120
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• 2018

The distributional characteristics of fault segments in Cretaceous and Tertiary rocks from southeastern Gyeongsang Basin were derived. The 267 sets of fault segments showing linear type were extracted from the curved fault lines delineated on the regional geological map. First, the directional angle(${\theta}$)-length(L) chart for the whole fault segments was made. From the related chart, the general d istribution pattern of fault segments was derived. The distribution curve in the chart was divided into four sections according to its overall shape. NNE, NNW and WNW directions, corresponding to the peaks of the above sections, indicate those of the Yangsan, Ulsan and Gaeum fault systems. The fault segment population show near symmetrical distribution with respect to $N19^{\circ}E$ direction corresponding to the maximum peak. Second, the directional angle-frequency(N), mean length(Lm), total length(Lt) and density(${\rho}$) chart was made. From the related chart, whole domain of the above chart was divided into 19 domains in terms of the phases of the distribution curve. The directions corresponding to the peaks of the above domains suggest the directions of representative stresses acted on rock body. Third, the length-cumulative frequency graphs for the 18 sub-populations were made. From the related chart, the value of exponent(${\lambda}$) increase in the clockwise direction($N10{\sim}20^{\circ}E{\rightarrow}N50{\sim}60^{\circ}E$) and counterclockwise direction ($N10{\sim}20^{\circ}W{\rightarrow}N50{\sim}60^{\circ}W$). On the other hand, the width of distribution of lengths and mean length decrease. The chart for the above sub-populations having mutually different evolution characteristics, reveals a cross section of evolutionary process. Fourth, the general distribution chart for the 18 graphs was made. From the related chart, the above graphs were classified into five groups(A~E) according to the distribution area. The lengths of fault segments increase in order of group E ($N80{\sim}90^{\circ}E{\cdot}N70{\sim}80^{\circ}E{\cdot}N80{\sim}90^{\circ}W{\cdot}N50{\sim}60^{\circ}W{\cdot}N30{\sim}40^{\circ}W{\cdot}N40{\sim}50^{\circ}W$) < D ($N70{\sim}80^{\circ}W{\cdot}N60{\sim}70^{\circ}W{\cdot}N60{\sim}70^{\circ}E{\cdot}N50{\sim}60^{\circ}E{\cdot}N40{\sim}50^{\circ}E{\cdot}N0{\sim}10^{\circ}W$) < C ($N20{\sim}30^{\circ}W{\cdot}N10{\sim}20^{\circ}W$) < B ($N0{\sim}10^{\circ}E{\cdot}N30{\sim}40^{\circ}E$) < A ($N20{\sim}30^{\circ}E{\cdot}N10{\sim}20^{\circ}E$). Especially the forms of graph gradually transition from a uniform distribution to an exponential one. Lastly, the values of the six parameters for fault-segment length were divided into five groups. Among the six parameters, mean length and length of the longest fault segment decrease in the order of group III ($N10^{\circ}W{\sim}N20^{\circ}E$) > IV ($N20{\sim}60^{\circ}E$) > II ($N10{\sim}60^{\circ}W$) > I ($N60{\sim}90^{\circ}W$) > V ($N60{\sim}90^{\circ}E$). Frequency, longest length, total length, mean length and density of fault segments, belonging to group V, show the lowest values. The above order of arrangement among five groups suggests the interrelationship with the relative formation ages of fault segments.

• Restorative Dentistry and Endodontics
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• v.25 no.3
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• pp.390-398
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• 2000

The purpose of this study was to evaluate the apical fitness of non-standardized gutta-percha cones in root canals prepared with rotary Ni-Ti root canal instruments of various tapers and apical tip sizes. Simulated sixty curved root canals of plastic blocks were prepared with crown-down technique using rotary root canal instruments of Maillefer ProFile$^{(R)}$ .04 and .06 taper (Maillefer Instrument SA, Switzerland). Specimens were divided into six groups and prepared as follows: Group 1, prepared up to size 25 of .04 taper ; Group 2, prepared up to size 30 of .04 taper ; Group 3, prepared up to size 35 of .04 taper ; Group 4, prepared up to size 25 of .06 taper ; Group 5, prepared up to size 30 of .06 taper ; Group 6 ; prepared up to size 35 of .06 taper. After cutting off the coronal portion of plastic, blocks perpendicular to the long axis of the canal with the use of a diamond saw, apical 5mm of canal space was analyzed. Prepared apical canal spaces were duplicated using rubber base impression material to evaluate two dimensional total area of apical canal space. Various sized gutta-percha cones were applied in the 5mm-apical canal space, which were size 25, size 30 and size 35 standardized gutta-percha cone, Diadent Dia-Pro ISO-.04$^{TM}$ and .06$^{TM}$(Diadent, Korea), and medium-fine (MF), fine (F), fine-medium (FM) and medium (M) sized non-standardized gutta-percha cones (Diadent, Korea). Coronal excess gutta-percha were cut off with a sharp blade. Photographs of impressed apical canal spaces and gutta-percha cones were taken with a CCD camera under a stereomicroscope and stored in a computer. Areas of the total canal space and gutta-percha cones were calculated using a digitalized image analysing program, CompuScope (Sungjin Multimedia Co., Korea). Ratio of apical fitness was obtained by calculating the area of gutta-percha cone to the total area of the canal space. The data were analysed statistically using One-way Analysis of Variance and Duncan's Multiple Range Test. The results were as follows: 1. In canals prepared up to size 25 ProFile$^{(R)}$ of .04 taper, non-standardized MF and F cones occupied significantly more canal space than Dia-Pro ISO-.04$^{TM}$ or size 25 standardized ones (p<0.05). 2. In canals prepared up to size 30 ProFile$^{(R)}$ of .04 taper, non-standardized F cones occupied significantly more canal space than Dia-Pro ISO-.04$^{TM}$ or size 30 standardized ones (p<0.05), and non-standardized MF cones occupied more canal space than size 30 standardized ones (p<0.05). 3. In canals prepared up to size 35 ProFile$^{(R)}$ of .04 taper, there was no significant difference in canal space occupation among non-standardized MF and F, size 35 standardized, and Dia-Pro ISO-.04$^{TM}$ cones (p>0.05). 4. In canals prepared up to size 25 ProFile$^{(R)}$ of .06 taper, non-standardized MF and F cones occupied significantly more canal space than Dia-Pro ISO-.06$^{TM}$, or size 25 standardized ones (p<0.05), and Dia-Pro ISO-.06$^{TM}$, cones occupied significantly more space than size 25 standardized ones (p<0.05). 5. In canals prepared up to size 30 ProFile$^{(R)}$ of .06 taper, non-standardized FM cones occupied significantly more canal space than Dia-Pro ISO-.06$^{TM}$ or size 30 standardized ones (p<0.05), and non-standardized F cones occupied significantly more canal space than size 30 standardized ones (p<0.05). 6. In canals prepared up to size 35 ProFile$^{(R)}$ of .06 taper, non-standardized M and FM, Dia-Pro ISO-.06$^{TM}$ occupied significantly more canal space than size 35 standardized ones (p<0.05). In summary, in both canals prepared with .04 or .06 taper ProFile$^{(R)}$, non-standardized cones showed better fitness than Dia-Pro ISO$^{TM}$ or standardized ones, which was more characteristic in smaller canals.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.36 no.3
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• pp.26-36
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• 2018

This study aims to examine the characteristics of landscape through the analysis of location and the landscape of Gugok while also conducting the empirical study through the literature review, field study, and digital analysis of the Okgung Gugok. Oksan Gugok is a set of songs set in Ogsan Creek(玉山川)or Jagyese Creek(紫溪川, 紫玉山), which flows in front of the Oksan Memorial Hall(李彦迪), which is dedicated to the Lee Eong-jeok (李彦迪). We first ascertained the location and configuration of Oksan Gogok. Second, we confirmed the accurate location of Oksan Gogok by utilizing the digital topographic map of Oksan Gogok which was submitted by Google Earth Pro and Geographic Information Center as well as the length of the longitude of the gravel measured by the Trimble Juno SB GPS. Through the study of the literature and the field investigation, The results of the study are as follows. First, Yi Eonjeok was not a direct composer of Oksan Gugok, nor did he produce "Oksan Gugokha(Music)". Lee Ia-sung(李野淳), the ninth Youngest Son of Tweo-Kye, Hwang Lee, visited the "Oksan Gugokha" in the spring of 1823(Sunjo 23), which was the 270th years after the reign of Yi Eonjeok. At this time, receiving the proposal of Ian Sung, Lee Jung-eom(李鼎儼), Lee Jung-gi(李鼎基), and Lee Jung-byeong(李鼎秉), the descendants of Ian Sung set up a song and created Oksan Gugok Music. And the Essay of Oksan Travel Companions writted by Lee Jung-gi turns out being a crucial data to describe the situation when setting up the Ok-San Gugok. Second, In the majority of cases, Gogok Forest is a forest managed by a Confucian Scholar, not run by ordinary people. The creation of "Oksan Bugok Music" can be regarded as an expression of pride that the descendants of Yi Eonjeok and Lee Hwang, and next generation of several Confucian scholars had inherited traditional Neo-Confucian. Third, Lee Jung-eom's "Oksan Donghaengki" contains a detailed description of the "Oksan Gugokha" process and the process of creating a song. Fourth, We examined the location of one to nine Oksan songs again. In particular, eight songs and nine songs were located at irregular intervals, and eight songs were identified as $36^{\circ}01^{\prime}08.60^{{\prime}{\prime}}N$, $129^{\circ}09^{\prime}31.20^{{\prime}{\prime}}E$. Referring to the ancient kingdom of Taojam, the nine-stringed Sainam was unbiased as a lower rock where the two valleys of the East West congregate. The location was estimated at $36^{\circ}01^{\prime}19.79^{{\prime}{\prime}}N$, $129^{\circ}09^{\prime}30.26^{{\prime}{\prime}}E$. Fifth, The landscape elements and landscapes presented in Lee Jung-eom's "Oksan Gugokha" were divided into form, semantic and climatic elements. As a result, Lee Jung-eom's Cho Young-gwan was able to see the ideal of mountain water and the feeling of being idle in nature as well as the sense of freedom. Sixth, After examining the appearance of the elements and the frequency of the appearance of the landscape, 'water' and 'mountain' were the absolute factors that emphasized the original curved environment at the mouth of Lee Jung-eom. Therefore, there was gugokga can gauge the fresh ideas(神仙思想)and retreat ever(隱居思想). This inherent harmony between the landscape as well as through the mulah any ideas that one with nature and meditation, Confucian tube.