• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.1
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• pp.163-170
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• 2019

In recent years, various types of industrial wastes are rapidly increasing with the development of high-tech industries. Specially, high-density waste glass of CRT TV containing heavy metals are buried or disposed of due to reprocessing costs and environmental pollution problems. Thus, more basic research is needed to recycle waste such as CRT waste glass such. In this study, the fundamental properties and radiation shielding performance of mortar specimens substituted CRT waste glass as a fine aggregate were analyzed and their application to shielding materials was evaluated. According to the results, the bulk density of mortar specimen replaced with CRT waste glass was increased and the compressive strength and flexural strength were decreased. Meanwhile, the CRT waste glass substitute specimen containing a large amount of lead component showed a higher shielding performance than the general mortar specimen. Especially, the linear attenuation coefficient of CRT waste glass in $122KeV{\cdot}^{57}Co$ of the low energy field was 2.5 times higher than that of normal specimen.

• The Korean Journal of Applied Statistics
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• v.32 no.2
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• pp.173-185
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• 2019

Causal questions are prevalent in scientific research, for example, how effective a treatment was for preventing an infectious disease, how much a policy increased utility, or which advertisement would give the highest click rate for a given customer. Causal inference theory in statistics interprets those questions as inferring the effect of a given intervention (treatment or policy) in the data generating process. Causal inference has been used in medicine, public health, and economics; in addition, it has received recent attention as a tool for data-driven decision making processes. Many recent datasets are observational, rather than experimental, which makes the causal inference theory more complex. This review introduces key concepts and recent trends of statistical causal inference in observational studies. We first introduce the Neyman-Rubin's potential outcome framework to formularize from causal questions to average treatment effects as well as discuss popular methods to estimate treatment effects such as propensity score approaches and regression approaches. For recent trends, we briefly discuss (1) conditional (heterogeneous) treatment effects and machine learning-based approaches, (2) curse of dimensionality on the estimation of treatment effect and its remedies, and (3) Pearl's structural causal model to deal with more complex causal relationships and its connection to the Neyman-Rubin's potential outcome model.

• Korean Journal of Heritage: History & Science
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• v.52 no.2
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• pp.4-19
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• 2019

Despite continuous volatility in ideological leanings, South Korean governments, conservative or progressive, have published a series of plans for aiding the economic development of North Korea. The Moon administration's plan is the paragon of such efforts. In addition, recent detente between the North Korean regime and the US government evokes much hope in its success. There is, hidden behind the veil of hope, apprehension about the crisis of management of cultural heritage in the North Korean region. It is believed that development policies may overwhelm efforts at conservation of cultural heritage, in particular that the hurrying of development projects would provoke insufficient and inappropriate investigation of archaeological sites., If these problems arise, responsibility for their resolution would be carried by South Korean archaeologists and governmental institutes. This paper reviews what the South Korean government has suggested for North Korea's economic recovery and examines what capability the South Korean archaeology sector has for investigating North Korean cultural heritage. It then discusses the scale of investigation needed, and what should beused as precedent in planning substantial excavations when development projects are performed in the North Korean region. Constructing a digital map system for cultural heritage of North Korea is suggested as one of the most urgent tasks precedent to substantial excavations. It is of great importance because we do not currently have any substantial information about the locations and current condition of cultural heritage sites and artifacts in the North Korean region. The mapping of Bronze Age sites in North Korea, conducted as a sort of pilot test, revealed that archaeological sites are densely distributed in several regions, especially Hwanghae-do and Pyoyang Directly-Administrated City, and that there is high potential of discovering new sites.

• Korean Journal of Heritage: History & Science
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• v.48 no.2
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• pp.96-109
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• 2015

The Dresden Elbe Valley of Germany was delisted from the World Heritage List after a long dispute amongst the city of Dresden, UNESCO and the World Heritage Committee upon a plan to build a four-lane bridge within the boundaries of the property. The plan was claimed to threaten the Outstanding Universal Value of the heritage embedded in the view of the river landscape. However looking back on the necessity of the bridge in order to maintain the city dynamics and the needs of the local population, it is possible to diagnose that plans for the bridge had a rather different nature from the usual urban 'development' plans appearing in the vicinity of other World Heritage properties. This article examines the process that led to the delisting of the Elbe Valley from the World Heritage List and assesses the problems arising between the entities which determine the value of the heritage and the entities that implement conservation measures. Recognizing the necessity of involving the local residents, this article stresses the importance of the role of communities in heritage conservation. It is also important to set up dependable directions for establishing conservation policies which takes into account the changing dynamics of the living environment, and sound methods for assessing the impact of future projects on the heritage.

• Korean Journal of Heritage: History & Science
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• v.50 no.2
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• pp.4-25
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• 2017

The Hoeamsa Temple of Yangju City was established at least during the late Korea Dynasty. This temple was rebuilt several times with the support of the royal family from the late Korea Dynasty to the early Joseon Dynasty. It was continually rebuilt in association with JiGong monk, HyeKeun monk, and MuHak monk. Hoeamsa temple was leading the Buddhist culture as a Buddhist center of the Joseon Dynasty . It was destroyed in the late Joseon Period. This site has been excavated several times since 1997. Various roofing tiles were unearthed. Of these tiles the edge of eaves are the artifacts showing the best features of this era. In this temple site has been excavated a variety of Sanskrit roof tiles. These tiles were made using superior technique. On the roof tiles are engraved Sanskrit mantras with a variety of 1 to 9 words. The jeongbeopkkye mantra(oṃ raṃ) and six-word mantra(oṃ ma ṇi pa dme hūṃ) were discovered the most. These mantras were believe to expel several evils from the Buddhist temple. It must have been that the six-word mantra culture became prevalent and provided a turning point in the history of Korean Buddhism. We can clearly know when some of the Sanskrit roof tiles were first manufactured. These roof tiles are the absolute standard of the other Sanskrit roof tiles excavated from different Buddhist temples. The master craftsmen must have been very skilled, understood the mantra very well, and had deep faith in the Sanskrit mantra. Hoeamsa Temple is a milestone in studying the Sanskrit roof tiles. More studies on various aspects are expected to be followed.

• Korean Journal of Heritage: History & Science
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• v.47 no.1
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• pp.4-17
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• 2014

The more income and free time people have, the more interest in cultural heritage they get to improve the quality of life. In light of this, Local governments put more effort to create colorful events using their cultural heritage resources, and the central government also starts to implement policies to enhance the value of cultural heritage. To keep those efforts on utilizing cultural heritage, however, several issues seem to be addressed in advance. Firstly, it needs to define the concept of cultural heritage utilization that could cover its current policy trend. Secondly, the utilization methodology should be categorized and classified. Therefore, the study for those issues should be carried out to utilize the cultural heritage efficiently and systematically. This study contains the current status of the relevant policies and projects; the trend and meaning of the utilization. And, in this study, the cultural heritage utilization was defined as all activities producing positive effects or influences by cultural heritage such as enjoying cultural heritage values and creating additional profits. Furthermore, the cultural heritage utilization was categorized according to several criteria; the value, the objective, and the type of cultural heritage utilization. Finally, the final part of the study includes proposals on the future policy direction of cultural heritage utilization.

• Korean Journal of Ichthyology
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• v.31 no.2
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• pp.67-76
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• 2019

This study was conducted from 2017 to 2018 to determine habitat aspects of Acheilognathus signifier, an endangered species reintroduced (2010~2012) to Heukcheon Stream, a tributary of the Hangang River, Korea. A total of 329 individuals were collected in 2017 (two surveys) and 723 individuals were collected in 2018 (four surveys) at about 5 km habitat area, including the discharge station. A. signifier's habitat was about 0.4 to 1.2 meters deep in slow water flow upstream of the discharge area. It was a place with many boulders and cobbles. The spawning period was estimated from April to June in terms of spawning behavior and collected juvenile size. Sex ratio of females (438) and males (412) was 1 : 0.94. Estimated age of A. signifier based on their total length distribution during the spawning period (April) indicated that 1-, 2-, 3-year old groups and more than 4-year-old group were 32~43 mm, 50~61 mm, 62~75 mm, and 76~89 mm, respectively. Age-specific composition costs differed depending on the timing of the collection. They were relatively high in the order of first-year (juvenile)>third-year> and fourth-year or higher, showing a stable age structure. Thus, A. signifier reintroduced to Heukcheon Stream has successfully settled down and formed a stable population, showing a tendency to proliferate.

• Korean Journal of Heritage: History & Science
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• v.47 no.4
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• pp.162-177
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• 2014

This article examined the burial type, wooden coffin and its historical significance of Iksan Ssangneung, the royal tombs of Baekje. Ssangneung was found to be the royal tombs of King Mu(武王) and queen through the burial type, wooden coffin, articles such as chinese jade ornaments and the deep relationship between King Mu and Iksan region. The reason of constructing Baekje royal tombs in Iksan region can be examined at many aspects. First, Iksan was a very important place for King Mu. Because Iksan was the basis of his political growth. Also, Iksan was a important geopolitical location in relation with Silla(新羅). For this reason, Iksan was developed in earnest. The construction of major facilities such as royal palace and temples in Iksan suggest the transfer of the capital from Sabi(泗?) or the preparation and partial execution at least. However, the transfer of the capital was not completed. It can be seen as the incomplete city. However, even after King Mu Iksan was maintained as the important region by King Euja(義慈王). It can be seen through the maintenance of great temples such as Jeseoksa(帝釋寺) and Mireuksa(彌勒寺) built at later period of King Mu and royal palace area, even though royal palace had turned into the temple. These inherited consciousness may have been embodied in the act of building royal tombs of King Mu and queen.

• Korean Journal of Heritage: History & Science
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• v.47 no.1
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• pp.46-65
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• 2014

This study, under the title of Daeungbojeon Hall of Bulyeongsa Temple, Uljin and the architectural technique of the architect, aimed to make a comprehensive speculation on Daeungbojeon Hall of Bulyeongsa Temple whose accurate construction year was confirmed in 1725. While existing studies dealt with it separately between construction and Buddhist art history this study attempted to sort out it in one perspective by means of comparison with compatible objects in the area. The results are as follows. 1st, by means of comparison of wall painting of Daeungbojeon Hall of Bulyeongsa Temple and other wall paintings of Gyeongsang-do Province, it was estimated to be created before and after 1725, the founding year of the building. 2nd, the stylobate of Daeungbojeon Hall is the only and unique case that Guibu was supported by the bottom. Such stylobate was estimated to be built in the early period of Goryeo stylobate of PostLintel Construction which was more simplified than that of the traditional unified Silla period considering specific techniques. Lastly, by means of comparison of the architectural technique of Daeungbojeon Hall of Bulyeongsa Temple with other temples in Gyeongsang-do Province, the characteristics of the building were found. In particular, the same architectural technique was confirmed by direct comparison of style with Yeongsanjeon Hall of Tongdosa Temple in 1714 which was constructed by the same architect.

• Korean Journal of Heritage: History & Science
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• v.50 no.2
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• pp.40-61
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• 2017

This study investigated material characteristics of composition and variable strength measurement using physicochemical and petrographic analysis for lime-soil mixture barrier tombs of Guri Galmae site in Joseon Dynasty. The tomb barriers are composed mainly of microcrystalline calcite, quartz, feldspar and mica with lime matrix. The lime matrix shows compact sheet texture, and some samples show hydration aggregates with needle-shaped textures. Gypsum occurred as a secondary process where carbonization reactions were poor. Concentrations of CaO in the tomb barrier very widely ranged from 4.43 to 36.19 wt.%, specific gravity and absorption ratio of the materials show of 1.35 to 1.62 and 20.1 to 32.6%, respectively. As the rebound hardness, the materials ranged from 10.0 to 28.4 (mean 15.7). The values are higher in the $-90^{\circ}$ direction rather than in the $0^{\circ}$ direction with the consequence that the values indicate more strength toward the vertical direction. Difference in strength by directions was caused by the directions of the tomb barriers, which is related to the processes in each stage. In the tomb barriers, ultrasonic velocity and unconfined compressive strength ranged from 1,049.2 to 1,728.9m/s and under 5.00MPa, respectively. Variation patterns between the two are very similar in values. As the result of composition and strength, the materials of higher contents on CaO are higher in strength values. Generally, techniques and skills to make the lime-soil mixture barriers are interpreted as low qualities in relatively.