• Journal of the Korean Geosynthetics Society
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• v.17 no.4
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• pp.119-128
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• 2018

Limit state design has been implemented in Korea since 2015; however, there exists no specification of lateral load determination on retaining wall due to the Korean standard traffic load on retaining wall's backfill surface. The lateral load from traffic depends on lane number, standard truck's axle loads and locations, loading distance from the inner wall. The concept of equivalent height of soil accounting for traffic loadings is typically used for design of retaining walls to quantify the traffic loads transmitted to the inner wall faces. Due to the different characteristics of the standard design trucks between Korea and US (AASHTO), the direct use of the guidelines from AASHTO LRFD leads to incorrect estimation of traffic load effects on retaining walls. This paper presents the results of evaluation of equivalent height of soil to reflect the Korean standard truck, based on the findings from analytical solutions using Bounessq's theory and numerical assessment using 2D finite element method. Consequently, it was found that the equivalent heights of soil from the Korean standard truck load were lower for lower retaining wall height.

• Journal of the Korean Geosynthetics Society
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• v.17 no.4
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• pp.53-64
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• 2018

In this study, the evaluation to probability of failure for risk assessment of port structures on DCM reinforced soils, where stability and risk assessment are increasing in importance, was performed. As a random variables affecting the risk of DCM improved ground, the design strength, superposition (overlap) of construction, strength of the natural ground, internal friction angle and unit weight of the modified ground were selected and applied to the risk assessment. In addition, the failure probability for the entire system under ordinary conditions and under earthquake conditions were analyzed. As a result, it was found that the highest coefficient of variation in the random variable for the risk assessment of the DCM improved ground is the design strength, but this does not have a great influence on the safety factor, ie, the risk of the system. The main risk factor for the failure probability of the system for the DCM reinforced soils was evaluated as horizontal sliding in case of external stability and compression failure in case of internal stability both at ordinary condition and earthquake condition. In addition, the failure probability for ordinary horizontal sliding is higher than that for earthquake failure, and the failure probability for ordinary compression failure is lower than that for earthquake failure. The ordinary failure probability of the entire system is similar to the failure probability on earthquake condition, but in this case, the risk of earthquake is somewhat higher.

• Journal of Climate Change Research
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• v.4 no.3
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• pp.291-303
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• 2013

After establishing national greenhouse gas emission reduction goals, the South Korean government has been pursuing sector- and industry-specific greenhouse gas emission reduction measures; in support of which, metropolitan city / state governing entities, such as Gyeonggi Province, etc., have been in lock steps by establishing and executing climate change measures that are appropriate for the regional characteristics. However, in the case of local governments, difficulties abound due to the fact that the per-unit greenhouse gas emission amounts and the future emission estimates for establishing reduction targets are not clear. In order to establish correct climate change measure policies, the policy directions and the assessment of verified greenhouse gas emission amounts would need to serve as the basis, and along with the national level climate change effect and vulnerability assessment, there's a need to develop methodologies that take into consideration the local characteristics and conditions. To this end, this study calculated the greenhouse gas emission amounts of the City of Siheung, a basic local government in Gyeonggi Province, by using the GEBT (Greenhouse gas Emission Business-as-usual Tool) developed by the National Institute of Environmental Research to facilitate easy calculations of BAU (business-as-usual) emission quantities by local governing entities.

• Korean Journal of Remote Sensing
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• v.34 no.6_2
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• pp.1193-1202
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• 2018

It is important to quantitatively analyze the energy budget for understanding of long-term climate change in Arctic. High-quality and long-term radiative parameters are needed to understand the energy budget. Since most of radiative flux components based on satellite are provide for a short period, several data must be used together. It is important to acquaint differences between data to link for conjunction with several data. In this study, we investigated the comparative analysis of Arctic radiative flux product such as CERES and GEWEX to provide basic information for data linkage and analysis of changes in Arctic climate. As a result, GEWEX was underestimated the radiative variables, and it difference between the two data was about $3{\sim}25W/m^2$. In addition, the difference in high-latitude and sea ice regions have increased. In case of comparing with monthly means, the other variables except for longwave downward flux represent high difference of $9.26{\sim}26.71W/m^2$ in spring-summer season. The results of this study can be used standard data for blending and selecting GEWEX and CERES radiative flux data due to recognition of characteristics according to ice-ocean area, season, and regions.

• Geophysics and Geophysical Exploration
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• v.24 no.1
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• pp.6-19
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• 2021

Subsurface physical properties can be obtained and imaged by seismic exploration, and various algorithms have been developed for this purpose. In this regard, root mean square error (RMSE) has been widely used to quantitatively evaluate the accuracy of the developed algorithms. Although RMSE has the advantage of being numerically simple, it has limitations in assessing structural similarity. To supplement this, full-reference image quality assessment (FR-IQA) techniques, which reflect the human visual system, are being investigated. Therefore, we selected six FR-IQA techniques that could evaluate the obtained physical properties. In this paper, we used the full-waveform inversion, because the algorithm can provide the physical properties. The inversion results were applied to the six selected FR-IQA techniques using three benchmark models. Using salt models, it was confirmed that the inversion results were not satisfactory in some aspects, but the value of RMSE decreased. On the other hand, some FR-IQA techniques could definitely improve the evaluation.

• New Physics: Sae Mulli
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• v.68 no.12
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• pp.1347-1355
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• 2018

This study aimed at investigating the physics curriculum implemented in science core schools. Thus, the researchers analyzed the science curriculum articulated in the annual reports of science core schools and interviewed some teachers in the schools to identify the features of the physics curriculum. The research findings were as follows: First, with respect to the teaching units by subjects, general science had the largest proportion, as much as 6.7 hours in average, and physics I and II were 4.2 and 4.4 hours, respectively, which were similar to other subjects such as chemistry, life science, and earth science. Second, most of schools opened the courses of physics I and II with two hours for two semesters. Fourteen schools taught physics I as an intensive unit whereas nine schools taught physics II intensively. In the case of specialized subjects, the most frequent one was independent research, and advanced physics was taught in 7 schools whereas physics experiments were done in 34 schools. Based on the findings, this study gives some implications about how to organize the physics curriculum in science core schools according to the 2015 revised science curriculum.

• Korean Journal of Remote Sensing
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• v.36 no.6_3
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• pp.1721-1732
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• 2020

Elementary school students spend a lot of time in a school and are more exposed to indoor air pollution. Also the students are physically growing and have a relatively high respiratory rate per unit weight compared to adults, so it is known that there is a high sensitivity to indoor air pollution. Therefore, indoor air quality in a school is becoming an important factor for the student's health. In this study, a correlation analysis using levels of indoor and outdoor Particulate Matter (PM) measured from five elementary schools in Seoul was performed to evaluate the effect of outdoor PM on indoor PM. PM ratio and indoor/outdoor (I/O) ratio were also analyzed to investigate the actual condition of indoor air quality and effect of outdoor PM on indoor PM. As a result, the correlation between indoor and outdoor PM in elementary school was more significant in PM2.5 and PM1 than PM10. In the case of I/O ratio, the I/O ratio of PM10 was higher than that of 1 in four elementary schools except SD (BB:2.21, NS: 1.67, IS: 1.73, SI: 1.17). This indicates that the activity of students has a great effect on the concentration of indoor PM10.

• Journal of Space Technology and Applications
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• v.2 no.1
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• pp.41-51
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• 2022

CubeSat is a satellite platform that is widely used not only for earth observation but also for space exploration. CubeSat is also used in magnetic field investigation missions to observe space physics phenomena with various shape configurations of magnetometer instrument unit. In case of magnetic field measurement, the magnetometer instrument should be far away from the satellite body to minimize the magnetic disturbances from satellites. But the accommodation setting of the magnetometer instrument is limited due to the volume constraint of small satellites like a CubeSat. In this paper, we investigated that the magnetic field interference generated by the cube satellite was analyzed how much it can affect the reliability of magnetic field measurement. For this analysis, we used a reaction wheel and Torque rods which have relatively high-power consumption as major noise sources. The magnetic dipole moment of these parts was derived by the data sheet of the manufacturer. We have been confirmed that the effect of the residual moment of the magnetic torque located in the middle of the 3U cube satellite can reach 36,000 nT from the outermost end of the body of the CubeSat in a space without an external magnetic field. In the case of accurate magnetic field measurements of less than 1 nT, we found that the magnetometer should be at least 0.6 m away from the CubeSat body. We expect that this analysis method will be an important role of a magnetic cleanliness analysis when designing a CubeSat to carry out a magnetic field measurement.

• Geophysics and Geophysical Exploration
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• v.26 no.3
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• pp.126-137
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• 2023

In this study, a recurrent neural network (RNN) was employed as a methodological approach to classify dolphin click signals derived from ocean monitoring data. To improve the accuracy of click signal classification, the single time series data were transformed into fractional domains using fractional Fourier transform to expand its features. Transformed data were used as input for three RNN models: long short-term memory (LSTM), gated recurrent unit (GRU), and bidirectional LSTM (BiLSTM), which were compared to determine the optimal network for the classification of signals. Because the fractional Fourier transform displayed different characteristics depending on the chosen angle parameter, the optimal angle range for each RNN was first determined. To evaluate network performance, metrics such as accuracy, precision, recall, and F1-score were employed. Numerical experiments demonstrated that all three networks performed well, however, the BiLSTM network outperformed LSTM and GRU in terms of learning results. Furthermore, the BiLSTM network provided lower misclassification than the other networks and was deemed the most practically appliable to field data.

• Journal of the Daesoon Academy of Sciences
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• v.25_2
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• pp.1-43
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• 2015

Daesoonjinrihoe perceives that human suffering is caused not only by mental factors but also by the cosmic principle of Mutual Overcoming more fundamentally. The relationship influenced among all things in the universe is Mutual Beneficence and Mutual Overcoming. If these relations are properly cooperated in harmony, all things will reveal their energetic existence in a balanced state, however, if one side, particularly, Mutual Overcoming becomes excessive, indeed, it will cause trouble. That is, the sentient beings that are inclined to excessive Mutual Overcoming rather than indispensable Mutual Overcoming make grievances among themselves and cumulate them. In the end, heaven and earth lose its constant Way[常道], leading the sentient beings to all kinds of agonies. However, it may be a problem if every agony is depicted with Mutual Overcoming, that is, one single fixed frame, because Mutual Overcoming has to be interpreted diversely according to the circumstances. Thus, it is not possible to explain precisely about the agony if not understanding its spectrum. This study analyzed the ways how Daesoonjinrihoe explains the aspects of reasons and solutions to a variety of agonies. In the Supreme Scripture of Daesoonjinrihoe, the reasons for agony vary: first, it is caused by Mutual Overcoming of the cosmos itself, which is irrelevant to human beings. Secondly, man can be victimized because of Mutual Overcoming caused by man. Thirdly, there is a case of a victim who is damaged due to Mutual Overcoming caused by the other. Fourthly, man can be victimized because of Mutual Overcoming caused by someone else's unintended deeds. Fifthly, there is a case of man having agony in return when he, as a perpetrator, hurt others or resolve his inappropriate desires. Sixthly, man's deed unintendedly became a sin and have agony in return. Seventhly, man can be a self-perpetrator, conceiving vain desire, obsession and grievance. Eightly, there is a case of man having agony during enforcement of the law or practice of justice. Ninthly, man needs to endure agony during self-cultivation, enacting Reordering of the Universe(天地公事), ritual practice, promotion of fortune, and test. However, it is important to make sure that the reason for agony can interact with not only one but also diverse models in real situation. These nine models are included in the category of Mutual Overcoming; but, these cannot be classified in a single term, Mutual Overcoming because much information will be hidden, only to make it difficult to explain about agony more precisely. There are some characteristic observed in the concept of agony in Daesoonjinrihoe as follows: first, reasons for agony are caused by Mutual Overcoming although Mutual Overcoming can be interpreted differently according to the circumstances. Secondly, Daesoonjinrihoe makes a positive valuation for some agony. Thirdly, the solution to overcome a agony is brought to a conclusion, that is cultivation practice of Daesoonjinrihoe. Fourthly, the experience of agony and solution in Daesoonjinrihoe sometimes lie in the unit of family beyond individual. Fifthly, in the painful situation resulted from vain desire and obsession, Daesoonjinrihoe suggests a solution called Mutual Beneficence. That is, it emphasizes not only self-control but also active practice of considering others.