• Journal of the Korean Geotechnical Society
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• v.26 no.4
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• pp.59-68
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• 2010

Piping, a common form of internal embankment erosion, is caused by progressive movement of soil particles through an embankment. The phenomenon commonly occurs with precursory signs of development of fractures in dam structures, but also occurs without any noticeable signs in dams that showed satisfactory dam performance for several years, due to dissolution of soluble material in an embankment. While piping accounts for nearly 50% of the causes for dam failure, few studies have been made for systematic evaluation of the phenomenon. In this study, we attempted to monitor the changes in electrical resistivities of fill-dam material while a saddle dam is dismantled for the construction of emergency spillways of Daechung dam. Two artificial subhorizontal boreholes were drilled into the embankment structure to simulate piping along the two artificial flow channels. Monitoring of changes in electrical resistivity showed an increase in resistivity values during piping. Thus, the investigation of resistivity over time could be an effective method for piping prediction.

• The Journal of the Convergence on Culture Technology
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• v.9 no.5
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• pp.105-110
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• 2023

This article attempts to analyze John Greenleaf Whittier's anti-slavery poems. As a Quaker, he criticizes and satirizes the rife slavery in the mid nineteenth century. His thoughts are based on his religious belief. "The Farewell of a Virginia Slave Mother" depicts the mother who lost daughter for she was sold to the South. The harsh state of the corrupt South is described. In "Massachusettes to Virginia," the speaker, deploring the moral corruption of Virginia, denounces any attempt to return slaves to slave states. With a moonrise as a socio-political symbol, "Arisen at Last" celebrates the passage of law to protect fugitive slaves. Written after the Civil War, "The Peace Autumn" celebrates the peaceful situation in which Emancipation was declared. His efforts contributed to the abolitionist literature.

• Journal of Korea Water Resources Association
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• v.56 no.12
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• pp.895-903
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• 2023

This study investigates the impact of riparian vegetation in the floodplain on channel stability, changes in bend curvature, and meandering channel migration. In channels with riparian vegetation, over time, meander width remains relatively constant, but selective bank erosion leads to meander development and downstream movement. During this process, bank erosion and changes in the riverbed are not significant, and the channel maintains relatively constant conditions with reduced sediment discharge and minimal variability. As the density of vegetation increases, bank erosion rates decrease. The erosion rates along the riverbanks increase with the density of vegetation on the floodplain, thus affecting the development of meanders. This factor notably contributes to enhancing riverbank stability and influencing channel changes through floodplain vegetation. Bank erosion rates and dimensionless bend curvature are greatest when there is no riparian vegetation but decrease in conditions with vegetation. Furthermore, the relationship between lateral migration rate and dimensionless bend curvature is similar to that of bank erosion rates. Therefore, riparian vegetation enhances channel stability, influencing bank erosion, meander curvature, and meander migration.

• Geomechanics and Engineering
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• v.36 no.5
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• pp.427-440
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• 2024

This study concentrates on the 301 comprehensive caving working face, notable for its considerable mining height. The roof model is established by integrating prior geological data and the latest borehole rock stratum's physical and mechanical parameters. This comprehensive approach enables the determination of lithology, thickness, and mechanical properties of the roof within 50 m of the primary mining coal seam. Utilizing the transfer rock beam theory and incorporating mining pressure monitoring data, the study delves into the geometric parameters of the direct roof, basic roof movement, and roof pressure during the initial mining process of the 301 comprehensive caving working face. The direct roof of the mining working face is stratified into upper and lower sections. The lower direct roof consists of 6.0 m thick coarse sandstone, while the upper direct roof comprises 9.2 m coarse sandstone, 2.6 m sandy mudstone, and 2.8 m medium sandstone. The basic roof stratum, totaling 22.1 m in thickness, includes layers such as silty sand, medium sandstone, sandy mudstone, and coal. The first pressure step of the basic roof is 61.6 m, with theoretical research indicating a maximum roof pressure of 1.62 MPa during periodic pressure. Extensive simulations and analyses of roof subsidence and advanced abutment pressure under varying working face lengths. Optimal roof control effect is observed when the mining face length falls within the range of 140 m-155 m. This study holds significance as it optimizes the working face length in thick coal seams, enhancing safety and efficiency in coal mining operations.

• Journal of the Korean Geotechnical Society
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• v.26 no.7
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• pp.49-58
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• 2010

This paper presents experimental results of a series of 1-g shaking table model tests performed on end-bearing single piles and pile groups to investigate the effect of particle size on the dynamic behavior of soil-pile systems. Two soil-pile models were tested twice: first using Jumoonjin sand, and second using Australian Fine sand. In the case of single-pile models, the lateral displacement was almost within 1% of pile diameter which corresponds to the elastic range of the pile. The back-calculated p-y curves show that the subgrade reaction of the Jumoonjin-sand-model ground was larger than that of the Australian Fine-sand-model ground at the same displacement. This phenomenon means that the stress-strain behavior of Jumoonjin sand was initially stiffer than that of Australian Fine sand. This difference was also confirmed by resonant column tests and compression triaxial tests. And the single pile p-y backbone curves of the Australian fine sand were constructed and compared with those of the Jumoonjin sand. As a result, the stiffness of the p-y backbone curves of Jumunjin sand was larger than those of Australian fine sand. Therefore, using the same p-y curves regardless of particle size can lead to inaccurate results when evaluating dynamic behavior of soil-pile system. In the case of the group-pile models, the lateral displacement was much larger than the elastic range of pile movement at the same test conditions in the single-pile models. The back-calculated p-y curves in the case of group pile models were very similar in both sands because the stiffness difference between the Jumoonjin-sand-model ground and the Australian Fine-sand-model ground was not significantly large at a large strain level, where both sands showed non-linear behavior. According to a series of single pile and group pile test results, the evaluation group pile effect using the p-multiplier can lead to inaccurate results on dynamic behavior of soil-pile system.

• Journal of Christian Education in Korea
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• v.74
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• pp.227-253
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• 2023

Purpose of the Study: This paper focuses on a significant historical event, namely the Bremen teachers' movement of 1905, which aimed to abolish religious classes in public schools. By examining an incident in the German history of religious education that remains unfamiliar to the Korean Christian Association, I aim to explore the interconnected diachronic and synchronic influences involved in this particular event. Contents and Method: The religious controversy sparked by the Bremen Teacher's movement of 1905 marked the first official call for reform towards neutral religious education in schools. Several factors contributed to this debate, including the rise of civil society in the 19th century, advancements in science and scholarship, the emergence of social democracy, and the conflict between the Lutheran and Reformed Churches. This paper delves into the historical context of the controversy and analyzes its impact on the develop of religious education in Germany. As reflected in the Bremen Document, the official outcome of the Bremen Teacher's Movement, educators argued for the separation of religion and education, emphasizing that religion is a deeply personal matter. The document called for the adoption of value-neutral moral education in public schools, achieved through objective Bible-History classes. This paper explores the impact of the Bremen School Dispute of 1905 on the development of religious education in Germany. Specifically, the provisions of the Bremen State Constitution of 1948 and the German Basic Law of 1949 were influenced by the controversy, with Article 141 of the Basic Law - known as the 'Bremen Clause' - providing a legal basis for the exclusion of churches from religion-classes at Schools in Bremen. The Bible-History Classes advocated in the Bremen Documents served as the basis for the present-day Bremen religious education curriculum well known for neutral objective religion-classes. Conlusion: This study analyzes the background, content, and influence of the Bremen School Controversy, which remains relatively unknown in Korea. The findings of this study can contribute to the ongoing discussion of Christian school education in Korea, with an emphasis on maintaining a Christian identity while promoting religious publicity in the classroom.

• Journal of Korea Water Resources Association
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• v.42 no.2
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• pp.141-148
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• 2009

Each river in each country has peculiar channel characteristics at every section. Korea consists of mountains at the rate of 70%. Due to this, the sections that display unique channel form are scattered. One of the typical features is the narrow pass of channel section that presents in the process of the generation of alluvial channel and deformation channel. Around as this narrow pass of channel, it often comes to be regular flood disaster section. Regardless of this situation, investigations and plans that reflect channel characteristics at the narrow pass of channel have been wholly wanting until now. In accordance with this, we have investigated and analysed hydraulic significance and channel form of the narrow pass of channel in Seonsan in this study. The study has found real minute classification of sediment phenomenon at river bed of low flow channel on investigation section which is sand-bed river, but it was vaguely difficult to conclude that classification of sediment arises from explicit natural force. We were able to assume that the phenomenon comes from gentle bed slope, supply of river bed materials which is nearly uniformity. However, classification of sediment would come from collecting an aggregate rather than natural force. And we found that compound cross section conversion has been developing dramatically with channel form of movable bed section referring to movement which was active before at drainage district of the narrow pass of channel. With this, we could find the phenomenon that river width of low flow channel diminished largely. This kind of situation implies that it may cause compound section weighting, flood dimension decreasing, revetment at low flow channel or the local scour at bottom of levee when extraordinary flood occurs.

• Journal of Popular Narrative
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• v.25 no.4
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• pp.159-190
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• 2019

This paper aims to examine to the political unconsciousness of social movies that have caused social repercussions in the 2010s, and to study the social imagination of Korean films at that time. Korean Movies such as (2013), <1987>(2017) and (2017) reflect the ethos of civil society based on common sense and justice. The epic structure was the same as that of ordinary citizens, who move toward a public space (court, square) after awakening their political correctness. More than anything else, the fact that such films were based on "a historical fact" could have been a strategy to avoid censorship in the era of the blacklist. In these social films, courts and squares have become places for democracy. The conservative government of the time was tired of anti-government resistance and the politics of the square. Thus, films from directors and producers blacklisted were difficult to produce. That's why the court in the movie during this period could become a symbolic proxy for the "legitimate" reenactment of the politics of the square, which was subject to censorship and avoidance by the regime of the time. Meanwhile, the square has gradually become the main venue for political films that advocate "historic true stories." The square of the 1980s, which appeared in the movies, will be connected to the Gwanghwamun candlelight square that audiences experienced in 2017. Furthermore, it was able to reach the concept of an abstract square as an "open space for democracy." At the foundation of these works is a psychological framework that equates the trauma of the failed democratic movement of the 1980s to the trauma of the failed progressive movement of the 2010s. Through this study, we were able to see that social political films in the 2010s were quite successful, emphasizing "political correctness" and constitutional common sense. But they also had limitations as "de-political popular films" that failed to show imagination beyond the censorship of the blacklist era.

• The Journal of Fisheries Business Administration
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• v.24 no.1
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• pp.65-86
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• 1993

In this paper, fishery economics is reviewed to extend a basic opportunity for developing new fishery economics and to evaluate the effects of the import liberalization on the fish trade structure of Korea. The principle outline of extensions emphasis to realize the modern fishery problems based on fishery economics and develop the practical methodology in order to analyze the impacts of the import liberalization on the fishery and fishermen welfare. During the process of export - oriented industrilization, the role and position of fishery in the economy is changed dynamically. When faced with the imperative of the role and position of fishery in the economy, fishery economists and domestic policy makers must decide how to organize themselves for solving fishery problems under the new regime in the import liberalization on the fish trade. Fishery problems impacted by the new regime can not be solved by fishery itself but be solved by the centralized efforts of all contributors in national views. Therefore the new systematic analytical methodology must be develop and the traditional fishery economics must be related to the regional development strategy and fishery sociology as subsidiary theories specialized. Due to the impacts of the import liberalization on the fish trade structure, fishery economists face with radical changes in the domestic fishery : a place of the resources harvest to place of the combination resource harvest and its demand, a fishing as a resource exploitation to a fishing as a resource management, a traditional small scale costal fishing to a modernized and scaled fishing, fishery using the given natural resource itself to fishery as technology intensive industry, and a food supply industry to a welfare indusry based on the regional and economic resource and social environment. As these changes, fishery and its community's regional and economic resource and social environments as multiple roles of the regional economic development are emphasized in fishery economics under the new regime in the import liberalization on the fish trade. Furthermore, domestic policy makers and administrators in a public sector must realize the above radical changing trends in fishery and understand a social and economic environment in fishery and develop a new fishery structure focusing on the fishing system and the fishery laws. As this point, they make efforts to improve and develop fishery as a food supply industry. Japan, for example, has a non - governmental organization to conflict the problem of international fishery such as a movement of a civil environmental protection. Also fishermen in Japan already realized conservation and pollution problems in fishing as fundamental issues of human being.

• Journal of Korea Water Resources Association
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• v.53 no.7
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• pp.507-519
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• 2020

This study developed the radon measurement system that can be used for crustal movement monitoring and seismic occurrence and prediction, and compared and analyzed the results of test-operated radon measurement system and observed seismic occurrence cases. First, the developed radon measurement system consists of an NB-IoT radon measurement device, data center, data analysis, and data supply server. Because the measured radon data can be remotely trasmitted by using NB-IoT, this system is very suitable for installation and operation in unmaaned groundwater station. Second, the developed radon measurement device was test-operated at two groundwater stations in Gimpo from May to July 2019. The measured radon data was compared with the groundwater-level and electrical conductivity measurement data, and it was confirmed that the radon measurement device developed in this study has some potential for commercialization. Finally, from November 2019 to February 2020, three observed seismic cases and daily measured radon, groundwater-level, electrical conductivity data by the NB-IoT radon measurement device installed at three groundwater stations in Pohang, which is a test-bed, were compared and analyzed. As a result of the analysis, it was confirmed that the seismic occurrence correlated with radon, groundwater level, and electrical conductivity and all of these measured data will be able to provide basic data to help in seismic monitoring and prediction in the future.