• Journal of the Korean Geotechnical Society
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• v.23 no.4
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• pp.5-13
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• 2007

Many construction projects adopt grouting technology to prevent the leakage of groundwater or to improve the shear strength of the ground. Recognition as a feasible field procedure dates back to 1925. Since then, developments and field use have increased rapidly. According to improvement of grout materials, theoretical study on grout penetration characteristics is demanded. Fluid of grout always tends to flow from higher hydraulic potential to lower one and the motion of grout is also a function of formation permeability. Viscosity of pout is changed by chemical action while grout moves through pores. Due to the increment of viscosity, permeability is decreased. Permeability is also reduced by grout particle deposits to the soil aggregates. In this paper, characteristics of new cement grout material that has been developed recently are studied: injectable volume of new grout material is tested in two different grain sizes of sands; and the method to calculate injectable volume of grout Is suggested with consideration of change in viscosity and clogging phenomena. The calculated values are compared with injection test results. Viscosity of new grout material is found to increase as an exponential function of time. And lumped parameter $\delta$ of new grout material to be used for assessing deposition characteristics is estimated by comparing deposit theory with injection test results considering different soil types and different injection pressures. Injection test results show that grout penetration rate is decreased by the increase of grout viscosity and clogging phenomena.

• Korean Journal of Environmental Biology
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• v.41 no.1
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• pp.31-40
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• 2023

In 2022, the Korean Ministry of Environment designated Parthenium hysterophorus as an ecosystem-disturbing plant. The purpose of this study was to present a management plan for P. hysterophorus considering its distribution, morphological, physiological, and ecological characteristics, and to introduce various control techniques. P. hysterophorus is native to Central America and occurs in about 45 countries worldwide. However, in Korea, it only grows in some areas of Tongyeong and Changwon, Gyeongsangnam Province. P. hysterophorus is an annual plant and spreads by seeds, moves between countries in the process of importing and/or exporting agricultural seeds, and spreads by agricultural machinery and vehicles after introduction. P. hysterophorus releases parthenin, an allelochemical that suppresses the occurrence of the surrounding vegetation, from its stems and roots. In addition, P. hysterophorus causes damage to humans and livestock through various allergens. P. hysterophorus can be controlled by physical methods, such as cutting its stems or pulling roots, and by treatment with non-selective herbicides, such as glyphosate. Many biological control research studies have been conducted and, unfortunately, there is no a practical solution so far.

• Journal of Aerospace System Engineering
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• v.16 no.1
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• pp.49-55
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• 2022

The role of drones has been expanded to various fields such as agriculture, construction, and logistics. In particular, agriculture drones are emerging as an effective alternative to solve the problem of labor shortage and reduce the input cost. In this study therefore, we proposed the fruit recognition algorithm and harvesting mechanism for fruit harvesting drone system that can safely harvest fruits at high positions. In the fruit recognition algorithm, we employ "You-Only-Look-Once" which is a deep learning-based object detection algorithm and verify its feasibility by establishing a virtual simulation environment. In addition, we propose the fruit harvesting mechanism which can be operated by a single driving motor. The rotational motion of the motor is converted into a linear motion by the scotch yoke, and the opened gripper moves forward, grips a fruit and rotates it for harvesting. The feasibility of the proposed mechanism is verified by performing Multi-body dynamics analysis.

• The Journal of Korean Institute of Next Generation Computing
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• v.13 no.6
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• pp.124-131
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• 2017

Recently, drone is extending its range of usability. For example, the delivery, agriculture, industry, and entertainment area take advantage of drone mobilities. To control real drones, it needs huge amount of drone control training steps. However, it is risky; falling down, missing, destroying. The virtual drone system can avoid such risks. We reason that what kinds of technologies are required for building the virtual drone system. First, it needs that the virtual drone authoring tool that can assemble drones with the physical restriction in the virtual environment. We suggest that the drone assembly method that can fulfill physical restrictions in the virtual environment. Next, we introduce the virtual drone simulator that can simulate the assembled drone moves physically right in the virtual environment. The simulator produces a high quality rendering results more than 60 frames per second. In addition, we develop the physics engine based on SILS(Software in the loop simulation) framework to perform more realistic drone movement. Last, we suggest the virtual drone controller that can interact with real drone controllers which are commonly used to control real drones. Our virtual drone system earns 7.64/10.0 user satisfaction points on human test: the test is done by one hundred persons.

• Journal of the Daesoon Academy of Sciences
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• v.22
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• pp.345-385
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• 2014

The object of this thesis is to consider the meaning of sincerity(誠), reverence(敬) and faith(信) through Cha gyungseok's historical record. Cha gyungseok(車京石, 1880-1936) is a key disciple of Kang Jeungsan Sangjenim(姜甑山, 1871~1909) to whom Cha kyungseok has begun to follow since 1907, completing his wandering around Yeonghak-gye(英學契), Iljin-hoe(一進會) and Cheondo-gyo(天道敎) after the loss of his father[Cha Jikoo(車致九), 1851-1894] in Tonghak peasants revolution. To examine the meaning of sincerity, reverence and faith as cardinal points in Daesoonjinrihoe(大巡眞理會) creed, this research has taken note of Cha kyungseok's sincerity, reverence and faith who is said to be thought of himself as a head of Reconstruction Work for the Tonghak spitit's resolution of grievances, despite the Sangjenim's intention of using him for different usage due to his sincerity, reverence and faith. Especially, emphasis was given to the illumination of Cha gyungseok's change of sincerity, reverence and faith through closely reviewing his life prior to the encounter with Sangjenim, the process of following Sangjenim and his whereabouts after the ascension of Sangjenim. In addition, through Jeonkyeong(典經), this research also examines Cha kyeong seok's sincerity, reverence and faith along with his ambition contained in that sincerity, reverence and faith. Up to his ascension, Sangjenim has never saved his advice on Cha gyungseok's ambition. Leaving Sangjenim's advice behind, Cha gyungseok moves on to become a head of the Reconstruction Work for the Tonghak spitit's resolution of grievances without deserting the dream of being the Son of Heaven. Although, he showed his prowess as a religious sect leader called Bocheon-gyo boasting its 6 million believers and as a provisional emperor of the country named Sikuk, he ends his life as a head for the Resolution of grievances of kings, princes, generals and premiers due to the change of faith on Sangjenim and interruption of Japanese Imperial Government, without accomplishing his dream. The feature of past disciples suggests the direction of cultivation for our cultivators. Through Cha gyungseok's sincerity, reverence and faith, we could look back upon the meaning of sincerity, reverence and faith and conclude that a real sincerity, reverence and faith is the heart-mind trying to participate in Reconstruction Work of Heaven and Earth with a pure mind, contrary to the one coming out of greed.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.28 no.4
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• pp.133-142
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• 2023

In this paper, we built a data-driven artificial intelligence model using RNN-LSTM (Recurrent Neural Networks-Long Short-Term Memory) to predict the Lorenz system, and examined the possibility of whether this model can replace chaotic dynamic models. We confirmed that the data-driven model reflects the chaotic nature of the Lorenz system, where a small error in the initial conditions produces fundamentally different results, and the system moves around two stable poles, repeating the transition process, the characteristic of "deterministic non-periodic flow", and simulates the bifurcation phenomenon. We also demonstrated the advantage of adjusting integration time intervals to reduce computational resources in data-driven models. Thus, we anticipate expanding the applicability of data-driven artificial intelligence models through future research on refining data-driven models and data assimilation techniques for data-driven models.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.7
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• pp.760-769
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• 2023

A numerical simulations were performed to investigate the storm surge during the passage of Typhoon Maemi on the coast of Busan. The typhoon landed on the southern coasts of Korean Peninsula at 21:00, September 12, 2003 with a central pressure of 950 hPa, and the typhoon resulted on the worst coastal disaster on the coast of Busan in the last decades. Observed storm surges at Busan, Yeosu, Tongyoung, Masan, Jeju and Seogwipo harbors during the passage of the typhoon were compared with the computed data. The simulated storm surge time series were in good agreement with the observations. The simulated peak storm surges were estimated to be 230 cm at Masan harbor, 200 cm at Yeosu harbor and Tongyoung harbor, and 75 cm at Busan harbor. The computed storm surges along the east coast of Busan measure 52 to 55 cm, exhibiting a gradual reduction in surge height as one moves further from the coast of Busan. Therefore, coastal inundation due to the storm surge in the semi-enclosed bay can induce great disasters, and the simulated results can be used as the important data to reduce the impact of a typhoon-induced coastal disaster in the future.

• Journal of Internet of Things and Convergence
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• v.9 no.6
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• pp.57-62
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• 2023

This research is a comparative analysis of the U.S. S&P 500 index using the volatility breakout strategy against the Buy and Hold approach. The volatility breakout strategy is a trading method that exploits price movements after periods of relative market stability or concentration. Specifically, it is observed that large price movements tend to occur more frequently after periods of low volatility. When a stock moves within a narrow price range for a while and then suddenly rises or falls, it is expected to continue moving in that direction. To capitalize on these movements, traders adopt the volatility breakout strategy. The 'k' value is used as a multiplier applied to a measure of recent market volatility. One method of measuring volatility is the Average True Range (ATR), which represents the difference between the highest and lowest prices of recent trading days. The 'k' value plays a crucial role for traders in setting their trade threshold. This study calculated the 'k' value at a general level and compared its returns with the Buy and Hold strategy, finding that algorithmic trading using the volatility breakout strategy achieved slightly higher returns. In the future, we plan to present simulation results for maximizing returns by determining the optimal 'k' value for automated trading of the S&P 500 index using artificial intelligence deep learning techniques.

• Journal of Adhesion and Interface
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• v.24 no.4
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• pp.124-130
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• 2023

For automotive coating agents that require little change in characteristics due to changes in external temperature, changes in noise characteristics due to changes in the external environment are very important. Therefore, soft polyurethane with excellent cold resistance, weather resistance, and abrasion resistance, and polysiloxane whose -OH terminated and side chains are modified with amines, are widely used. In this study, coating agents was prepared by adding water-born polyurethane, polysiloxane, ultra high molecular weight polypropylene (UHMWPP) powder, carbon black, and a matting agent to determine the effect of each resin component on noise. To study the effect of each resin component on noise, a coating agent was prepared by adding water-born polyurethane, polysiloxane, UHMWPP powder, carbon black, and a matting agent. The hard/soft segment ratio of water-born polyurethane, the main component of the coating, was 27.1%/72.9%, and the ratio of amino siloxanes to hydroxy-terminated polysiloxane was 2:7, which produced the least noise. The difference in friction coefficient was large when the friction body moves at high speed. When UHMWPP powder replaced SiO₂, noise decreased and gloss also decreased.

• Trans-
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• v.16
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• pp.69-105
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• 2024

The House that Jack Built (2018), a film about how the protagonist Jack is reborn as a "mad artist" with psychotic symptoms during a 12-year killing spree, provides an interesting opportunity to analyze the film in terms of psychoanalysis and religion. Jack, an engineer who suffers from OCD, finds pleasure in the accidental murder of a character and considers killing people as an art form, overcoming his OCD in the process. The question we are interested in is whether the symptoms of OCD are truly overcome by the act of repeated killing. The idea is that Jack's OCD is not overcome by killing, but rather that the symptoms disappear as he moves from neurosis to a stabilized psychotic state. According to the theory of the famous French psychoanalyst Lacan, the hallucinations or delusions that human subjects experience when they lose their realistic stability are a phenomenon that occurs when they are confronted with The Real, which penetrates through the cracks of the symbolic system. Phenomena such as Jack's illusory reality and delusions in the movie are pathological symptoms of the absence of a paternal figure in his life, causing the Name-of-the-Father to fail to take hold. This paper deciphers the psychotic structure of Jack, the protagonist of Lars von Trier's House of Jack, through Lacanian psychoanalysis.