• The Journal of Engineering Geology
• /
• v.31 no.4
• /
• pp.621-630
• /
• 2021

This study evaluated cracks and climate monitoring in Ipseok-dae columnar joints and Jigong Neodeol rock blocks in Mudeungsan National Park. The rocks' state of cracking and their surface temperatures were measured alongside air temperature, relative humidity, and wind velocity. The maximum crack behavior in Ipseok-dae was 0.367 mm at one point, and showed a slight tendency at other points. One in Jigong Neodeol was within 0.15 mm and showed a stable state with little change. The surface temperature of the Ipseok-dae columnar joints was higher on the side exposed to sunlight than on the shaded side. All blocks of Jigong Neodeol rock showed similar temperatures. The air temperature showed a similar distribution for both rock types. The air temperature showed a similar distribution for both Ipseok-dae and Jigong Neodeol. The relative humidity was mostly between 20% and 60% in Ipseok-dae and was between 20 and 70% in Jigong Neodeol. Both areas had low wind speeds, with maxima of 5 m/s in Ipseok-dae and 3 m/s in Jigong Neodeol. As a result, it is evaluated that crack behavior in Ipseok-dae columnar joints and Jigong Neodeol rock blocks have maintained a very stable state so far. The surface temperature, temperature, relative humidity, and wind velocity of the two areas showed small difference depending on the season, indicating that they were affected to some extent by the season. From a long-term perspective, this can continuously affect the deformation of the Ipseok-dae columnar joints or Jigong Neodeol rock blocks. Therefore, in order to accurately evaluate their stability, it is considered that the current microscopic delamination and exfoliation or the propagation and expansion of cracks should be continuously measured.

• Journal of the Korea Institute of Building Construction
• /
• v.22 no.6
• /
• pp.651-662
• /
• 2022

The electrochemical impedance spectroscopy(EIS) method was used to evaluate the concrete deterioration process related to chloride-induced steel corrosion with various corrosion levels(initiation, rust propagation and acceleration periods). The impressed current technique, with four total current levels of 0C, 13C, 65C and 130C, was used to accelerate steel corrosion in concrete cylinder samples with w/c ratio of 0.4, 0.5, and 0.6, immersed in a 0.5M NaCl solution. A series of EIS measurements was performed to monitor concrete deterioration during the accelerated corrosion test in this study. Some critical parameters of the equivalent circuit were obtained through the EIS analysis. It was observed that the charge transfer resistance(R_c) dropped sharply as the impressed current increased from 0C to 13C, indicating a value of approximately 10kΩcm². However, the sensitivity of R_c significantly decreased when the impressed current was further increased from 13C to 130C after corrosion of steel had been initiated. Meanwhile, the double-layer capacitance value(C_dl) linearly increased from 50×10^-6μF/cm² to 250×10^-6μF/cm² as the impressed current in creased from 0C to 130C. The results in this study showed that monitoring C_dl is an effective measurement parameter for evaluating the progress of internal concrete damages(de-bonding between steel and concrete, micro-cracks, and surface-breaking cracks) induced by steel corrosion. The findings of this study provide a fundamental basis for developing an embedded sensor and signal interpretation method for monitoring concrete deterioration due to steel corrosion at various corrosion levels.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.24 no.4
• /
• pp.327-339
• /
• 2022

The purpose of this study is to present the effective smoke control flow rate and mode for securing safety through quantitative risk assessment according to the smoke control flow rate and mode (supply or exhaust) of the platform when a train fire occurs at the subway platform. To this end, a fire outbreak scenario was created using a side platform with a central staircase as a model and fire analysis was performed for each scenario to compare and analyze fire propagation characteristics and ASET, evacuation analysis was performed to predict the number of deaths. In addition, a fire accident rate (F)/number of deaths (N) diagram (F/N diagram) was prepared for each scenario to compare and evaluate the risk according to the smoke control flow rate and mode. In the ASET analysis of harmful factors, carbon monoxide, temperature, and visible distance determined by performance-oriented design methods and standards for firefighting facilities, the effect of visible distance is the largest, In the case where the delay in entering the platform of the fire train was not taken into account, the ASET was analyzed to be about 800 seconds when the air flow rate was 4 × 833 m³/min. The estimated number of deaths varies greatly depending on the location of the vehicle of fire train, In the case of a fire occurring in a vehicle adjacent to the stairs, it is shown that the increase is up to three times that of the vehicle in the lead. In addition, when the smoke control flow rate increases, the number of fatalities decreases, and the reduction rate of the air supply method rather than the exhaust method increases. When the supply flow rate is 4 × 833 m³/min, the expected number of deaths is reduced to 13% compared to the case where ventilation is not performed. As a result of the risk assessment, it is found that the current social risk assessment criteria are satisfied when smoke control is performed, and the number of deaths is the flow rate 4 × 833 m³/min when smoke control is performed at 29.9 people in 10,000 year, It was analyzed that it decreased to 4.36 people.

• Korean Journal of Plant Resources
• /
• v.35 no.4
• /
• pp.435-444
• /
• 2022

Hibiscus hamabo Sieb. et Zucc. (yellow hibiscus) is a deciduous semi-shrub plant and mainly growing in Jeju Island. This is known the unique wild hibiscus genus and classified as an 2nd grade of endangered plant for Korean Red List. In previous studies, properties of germination, ecological, genetical and salt resistance have been reported. In this study, we investigated mass-proliferated adventitious root using bioreactor, antioxidant and whitening effects to conduct functional ingredients. Yellow hibiscus were collected from Gujwa, Jeju by prior permission and they were introduced by explant type and various medium composition after surface sterilization. As a result, seed response rates were evaluated at range of 51.17~51.83%, in terms of comprehensive efficiency of shoot and root formation. In the case of adventitious root propagation condition was confirmed in half strength Murashige and Skoog medium salts, 30 mg/L sucrose, and 2 mg/L indole-3-butyric acid for 8 weeks in 5,000 mL bioreactor. We also compared between relationship with biomass and secondary metabolites accumulation by total phenolics content, the flavonoid content, DPPH free radical scavenging activity and melanin content. The results indicated that adventitious root mass proliferation, antioxidant and whitening effect could develop value of the high-quality cosmeceutical ingredient and further metabolite studies.

• Journal of the Daesoon Academy of Sciences
• /
• v.29
• /
• pp.241-278
• /
• 2017

This study aims to classify broadscale anti-religious movements in Korea based on critical public sentiment and analyze the meanings of these movements. To carry out the research, global religious changes that have occurred in modern times were closely looked into first. The world religions have had an influence on the world's religious awareness. As a result, they intend to acquire universality on their own individual grounds while keeping consistency with the past. This phenomenon used to appear to retain the identity, recreate tradition, transform itself to fit in the present times, pursue innovation, or even become overshadowed by other forms of thought such as when religions have collided with nationalism. How does Korean society perceive the changes that emerged in world religions? In general, the circumstances that Korea faces in this era tend to manifest themselves via the Internet, multimedia, and Youtube wherein they sound off on religion and this includes criticism of Christianity, demand for reformation, attack on minor religions, pro-reform academic circles and media, and the propagation of anti-theism. Criticism of religion is interpreted as an anti-religious movement. The secularism and anti-theism brought up by some Western scholars and critical theories of religion from scientific or historical perspectives are being spread through bookstores. Christianity is prone to reflecting on itself and trying to emphasizing a meta-religious spirituality. This in short, characterizes anti-religious movements in Korea. Indeed, criticism against particular religions has also emerged in the past. However, anti-religious movements that have recently come into existence in Korea are in some regards unprecedented when compared to that of the past in terms of their patterns and context. Especially, the active anti-Christianity movement in general is definitely a new phenomenon. This research mainly focused on Christianity, but on-going anti-religious movements will be a major topic for further research that aims to understand the religious changes unfolding in Korea.

• Journal of the Daesoon Academy of Sciences
• /
• v.31
• /
• pp.199-235
• /
• 2018

Most of the new religions derived from Jeungsan have claimed that Jeungsan's religious thought reproduced Dangun [檀君] Thought in its original form. However, Daesoon Jinrihoe is the only religious order out of the many new religions within the Jeungsan lineage, which has constantly kept its distance from Dangun Thought since 1909 during the earliest period of proto-Daesoon Jinrihoe. Even a mere trace of Dangun cannot be found in the subject of faith or the doctrinal system of Daesoon Jinrihoe. In this context, this study aims to examine possible connections between Daesoon Thought and Dangun Thought in order to determine why other Jeungsanist religions frequently exhibit Dangunist features. Specifically, a major part of this study will be devoted to comparing and analyzing the narrative structure of Daesoon Thought and Dangun Thought as well as their respective motifs. In fact, Jeungsan does not seem to have ever mentioned Dangun in his recorded teachings, therefore, after his passing into the Heaven, most of the religious orders including Daesoon Jinrihoe derived from him did not pay any attention to Dangun Thought for almost for 40 years. These orders did not originally perceive Dangun as an object of belief. After Korea's liberation, Dangun became widely accepted as a pivotal role among the Korean people. As Dangun-nationalism claimed to unify Koreans as one great Korean ethnic society, the religious orders of Jeungsan lineage also climbed aboard this creed and their faiths or doctrines were acculturated to reflect this change. The reason for this has been attributed to following modern trends to increase success in propagation. In the meantime, Daesoon Jinrihoe was the only order that did not accept Dangun-nationalism because it was not a teaching given by the order's founder. And the two systems of thought have more dissimilarity than parallelism in terms of philosophical ideology. These seem to be the main reasons why Daesoon Jinrihoe did not adopt Dangun into its doctrine or belief system.

• The Journal of the Convergence on Culture Technology
• /
• v.8 no.3
• /
• pp.581-587
• /
• 2022

The water god, Venerable Bhadra, Indian Tammola (Tamla as the 'mol' and 'ju' characters were eliminated) came to Tamla with 900 Arahants(The highest Buddhist monks) around 563-483 BC. It is the propagation of Buddhism through the world's most sacred water (Heiligkeit). The traces of the three surnames of Goyangbu are the first samsunghyeol and the dwelling of the den of Jonjaam(cave of venerable Bhadra) in Yeongsil, giving a glimpse into the era of living in caves. The second is a link that is in line with 3, the basic number in the decomposition of 900 (=3^*3^*100) disciples of Bhadra, considering that 3 and 3 of the three surnames in Goyangbu are three times 9. At this time, 3 is the person of heaven and earth, religiously, marriage, hope, or complete number, and Jeju culture is resting everywhere. For example, 3 of the samsunghyeol, 3 of the 1, 2, 3 Dodong, 3 of the 3 Dado, 3 of the 3 Mudo, 3 of the 3 disasters, 3 of the Goyangbu 3-surnames, 3 of the house Olle Jeongnang and, among 900 (=3^*3^*100) disciples of Venerable Bhadra, the common factor is 3. It is the 'island of 3'. These papers consist of 1 and 2 parts. In Part 1, the name of Tamla came from Tammola, India, and 900 Indian Buddhist Arahants estimated that the three surnames in Goyangbu were the ancestors. Part 2 highlights how the basic principle of jeonganag derived from Indian customs has evolved and is being used in modern mobile communication and DNA gene life science.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.35 no.6
• /
• pp.109-120
• /
• 2023

The High-Frequency Radar (HFR) is an equipment designed to measure real-time surface ocean currents in broad maritime areas.It emits radio waves at a specific frequency (HF) towards the sea surface and analyzes the backscattered waves to measure surface current vectors (Crombie, 1955; Barrick, 1972).The Seasonde HF Radar from Codar, utilized in this study, determines the speed and location of radial currents by analyzing the Bragg peak intensity of transmitted and received waves from an omnidirectional antenna and employing the Multiple Signal Classification (MUSIC) algorithm. The generated currents are initially considered ideal patterns without taking into account the characteristics of the observed electromagnetic wave propagation environment. To correct this, Antenna Pattern Measurement (APM) is performed, measuring the strength of signals at various positions received by the antenna and calculating the corrected measured vector to radial currents.The APM principle involves modifying the position and phase information of the currents based on the measured signal strength at each location. Typically, experiments are conducted by installing an antenna on a ship (Kim et al., 2022). However, using a ship introduces various environmental constraints, such as weather conditions and maritime situations. To reduce dependence on maritime conditions and enhance economic efficiency, this study explores the possibility of using unmanned aerial vehicles (drones) for APM. The research conducted APM experiments using a high-frequency radar installed at Dangsa Lighthouse in Dangsa-ri, Wando County, Jeollanam-do. The study compared and analyzed the results of APM experiments using ships and drones, utilizing the calculated radial currents and surface current fields obtained from each experiment.

• Journal of the Daesoon Academy of Sciences
• /
• v.47
• /
• pp.203-239
• /
• 2023

Jo Jeongsan's religious activity undertaken to benefit society can be organized into two categories. First, attention can be paid to Jo Jeongsan's religious activity of establishing religious order by enshrining Kang Jeungsan as the God of Ninth Heaven and making the Great Dao of Heaven and Earth the basic idea inspiring the social activity of his order. This was completed through the 50 years of propagation work carried out by Jo Joengsan in accordance with Kang Jeungsa's purpose of saving the world and its inhabitants. Second, his practice of social work in the field of people's lives based on the idea of the Dao can also be observed. This religious activity of Jo Jeongsan which began in 1909 was the sacred manifestation of his will to realize Kang Jeungsan's purpose of saving the world and people, and it was also a practice of spreading virtue throughout the world. In addition, Park Wudang carried out Sihak and Sibeop Gongbu (two varieties of holy work) for the cultivation of Dao trainees, and those methods came from the systematic cultivation practice established by Jo Jeongsan. Regarding this, we can refer to Kang Jeungsan's saying, "As the Dao shall dwell in the 12,000 peaks of Geumgang Mountain, the same number of sages who were enlightened to the Dao will be born into the world." The perfected state of human maturity or the emergence of people who are enlightened to the Dao would be the completion of the idea of saving the world and its inhabitants. Therefore, the holy works of Sihak and Sibeop that are now being carried out can be seen as the continuance of the pursuit of saving the world and humankind, as it was continually upheld by Park Wudang's predecessors, Jo Jeongsan and Kang Jeungsan.

• The Journal of the Acoustical Society of Korea
• /
• v.43 no.1
• /
• pp.9-18
• /
• 2024

The importance of active sonar systems is emerging due to the quietness of underwater targets and the increase in ambient noise due to the increase in maritime traffic. However, the low signal-to-noise ratio of the echo signal due to multipath propagation of the signal, various clutter, ambient noise and reverberation makes it difficult to identify underwater targets using active sonar. Attempts have been made to apply data-based methods such as machine learning or deep learning to improve the performance of underwater target recognition systems, but it is difficult to collect enough data for training due to the nature of sonar datasets. Methods based on mathematical modeling have been mainly used to compensate for insufficient active sonar data. However, methodologies based on mathematical modeling have limitations in accurately simulating complex underwater phenomena. Therefore, in this paper, we propose a sonar signal synthesis method based on a deep neural network. In order to apply the neural network model to the field of sonar signal synthesis, the proposed method appropriately corrects the attention-based encoder and decoder to the sonar signal, which is the main module of the Tacotron model mainly used in the field of speech synthesis. It is possible to synthesize a signal more similar to the actual signal by training the proposed model using the dataset collected by arranging a simulated target in an actual marine environment. In order to verify the performance of the proposed method, Perceptual evaluation of audio quality test was conducted and within score difference -2.3 was shown compared to actual signal in a total of four different environments. These results prove that the active sonar signal generated by the proposed method approximates the actual signal.