• Journal of Korea Water Resources Association
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• v.52 no.10
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• pp.743-752
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• 2019

The flow in the meandering channel is characterized by the spiral motion of secondary currents that typically cause the erosion along the outer bank. Hydraulic structures, such as spur dike and groyne, are commonly installed on the channel bottom near the outer bank to mitigate the strength of secondary currents. This study is to investigate the effects of submerged vanes installed in a $90^{\circ}$ meandering channel on the development of secondary currents through three-dimensional numerical modeling using the hybrid RANS/LES method for turbulence and the volume of fluid method, based on OpenFOAM open source toolbox, for capturing the free surface at the Froude number of 0.43. We employ the second-order-accurate finite volume methods in the space and time for the numerical modeling and compare numerical results with experimental measurements for evaluating the numerical predictions. Numerical results show that the present simulations well reproduce the experimental measurements, in terms of the time-averaged streamwise velocity and secondary velocity vector fields in the bend with submerged vanes. The computed flow fields reveal that the streamwise velocity near the bed along the outer bank at the end section of bend dramatically decrease by one third of mean velocity after the installation of vanes, which support that submerged vanes mitigate the strength of primary secondary flow and are helpful for the channel stability along the outer bank. The flow between the top of vanes and the free surface accelerates and the maximum velocity of free surface flow near the flow impingement along the outer bank increases about 20% due to the installation of submerged vanes. Numerical solutions show the formations of the horseshoe vortices at the front of vanes and the lee wakes behind the vanes, which are responsible for strong local scour around vanes. Additional study on the shapes and arrangement of vanes is required for mitigate the local scour.

• Journal of Wetlands Research
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• v.24 no.4
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• pp.331-344
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• 2022

This study analyzed the characteristics of the soil and hydrological environment of abandoned paddy wetlands examined the changes in land cover type in the ecological affect area, analyzed the environmental factors of abandoned paddy wetlands, and examined the changes in land cover type in the ecological impact area. The ecological environment characteristics of the reference abandoned paddy wetlands were investigated through literature research, environmental spatial information service, and preliminary exploration of the abandoned paddy wetlands, and the basic data for the restoration of abandoned paddy wetlands ware provided by examining the changes in land cover type in the ecological impact area for 40 years. Through this study, it will be possible to manage the rapidly increasing number of abandoned farmland to be converted into wetlands so that it can perform functions equivalent to or greater than that of natural wetlands. In particular, as we checked the clues that abandoned paddy wetlands could spread to surrounding ecological influences through land cover changes, the study sites are highly likely to be reference wetlands, and if the topography, soil, water circulation system, and carbon reduction performance are analyzed carefully, it will be possible to standardize the development process. In addition, through the change in land cover, clues were confirmed that the abandoned paddy wetlands could spread to the surrounding ecological affect areas. The land cover type in the ecological impact area, forests was mainly distributed, but generally decreased rapidly in the last 10-20 years, and forests were changing from coniferous forests to broad-leaved forests, mixed forests, or grassland. It has not yet been fully called to the wetland, and it is found that it has maintained the form of barren or grassland, and as can be seen in the case of natural wetlands after more than 30 years after abandoned, it is expected that the transition will gradually proceed to wetlands that are structurally and functionally similar to natural wetlands.

• Journal of the Korean Electrochemical Society
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• v.24 no.3
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• pp.65-75
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• 2021

Coin cell is a basic testing platform for battery research, discovering new materials and concepts, and contributing to fundamental research on next-generation batteries. Li metal batteries (LMBs) are promising since a high energy density (~500 Wh kg^-1) is deliverable far beyond Li-ion. However, Li dendrite-triggered volume fluctuation and high surface cause severe deterioration of performance. Given that such drawbacks are strongly dependent on the cell parameters and structure, such as the amount of electrolyte, Li thickness, and internal pressure, reliable Li metal coin cell testing is challenging. For the LMB-specialized coin cell testing platform, this study suggests the optimal coin cell structure that secures performance and reproducibility of LMBs under stringent conditions, such as lean electrolyte, high mass loading of NMC cathode, and thinner Li use. By controlling the cathode/anode (C/A) area ratio closer to 1.0, the inactive space was minimized, mitigating the cell degradation. The quantification and imaging of inner cell pressure elucidated that the uniformity of the pressure is a crucial matter to improving performance reliability. The LMB coin cells exhibit better cycling retention and reproducibility under higher (0.6 MPa → 2.13 MPa) and uniform (standard deviation: 0.43 → 0.16) stack pressure through the changes in internal parts and introducing a flexible polymer (PDMS) film.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.29 no.1
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• pp.28-37
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• 2011

In this study, the series-poem, Bihaedangsasippalyoung(48 poems for beautiful scene of Bihaedang), written by scholars of Jiphyonjeon for Bihaedang garden of Anpyung-Daegun(Prince Anpyung, 1416-1453), was analyzed focusing on scenery lexeme to interpret the meaning of scenery and gardening culture of Sadaebu(noblemen) during the first term of Chosun Dynasty. The study result is as followings. First, the subtitle of Sasippalyoung(48 poems) written by Anpyung-Daegun while he grew Bihaedang garden on the foot of Inwang Mountain showed repetitive nomativity comparing joining of yin and yang, such as life and form of animal and plan, time and space, meaning and symbolism, etc. Among scenery lexemes, 38 are represented plant and flowers, and 8 are represented gardening ornaments and animals. Second, the names of gardens were expressed as Wonrim, Jongje, Imchon(Trees and Ponds), or Hwawon(Flower garden), or also presented as Gongjeong(Empty garden), Manwon(Full garden), Jungjeong(Middle garden), Huwon(Backyard), Wonrak(Inner court), or Byulwon(Seperated garden) depending on density and location. In addition, there were pavilions and ponds, stepping stones and stairs, a pergola, a flat bench, flowerpots, an artificial hill, oddly shaped stones, wells, aviary, flower beds, or hedges. A gardener was called Sahwa(flower keeper), planting and gardening of garden trees were called Jaebae(cultivation), a pond island was called Boogoo(floating hill), and miniature landscapes were called Chukjee(reduced land). Third, willows were planted on the outdoor yard, and plum trees were planted in front of the library, which led to bamboo woods road. Peony, camellia, tree peony and crepe myrtle were planted on the inner court with mossy rocks, small artificial hills, glass rocks, flower pots. There were rectangular ponds, while breeding deer, dove, rooster, and cranes. Fourth, landscape elements were enjoyed as metaphysical symbolic landscape by anthropomorphism, such as (1) gentlemen and loyalty, (2) wealth and prosperity, (3) Taoist hermit and poetical life, (4) reclusion and seclusion, (5) filial piety, virtue, introspection, etc. In other words, the garden presented a variety of gardening culture appreciating meaningful landscape, such as investigation of things, reclusion and seclusion, and building orientation of a fairyland yearning eternal youth and Mureungdowon(Taoist Arcadia) by making a garden blending beautiful flowers and trees, with precious birds and animals. Fifth, there were many landscape appreciation schemes, such as Angkyung(looking-up), Bukyung(looking-down), Jeokyung(looking-under), Chakyung(bringing outer space into inside), Yookyung(flower viewing), Yojeong(walking around the garden enjoying flowers), Hwasaekhyangbyuk(flower gardening), and Garden appreciation enjoying landscape through time and seasons with different inspirations.

• The Journal of Korean Philosophical History
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• no.42
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• pp.259-294
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• 2014

The key concept of political thoughts of Confucianism is 'Tian(天)=the Heaven' and 'Ren(人)=the Human being'. In particular, the meaning of 'the Heaven(天)' is profoundly exclusive in Confucianism in comparison to the other concepts. It is because that 'the Heaven' is connected with 'Ri(理)' which explains the human being and the heaven metaphysically, and the discussions about those concepts have also been widening to the political field. And if the concept of 'the Heaven's nature(天命)' is excluded, it is difficult for us to discuss the essence of political thought of Confucianism. This paper argued how the politicalization of 'the Heaven' which was private dimension of monarch in the strict sense, changed to the public dimension of people in Japan in the early 18th century through some theories of the two famous philosopher, Ito-Jinsai(伊藤仁齋) and Ogyu-Sorai(荻生?徠) who belonged to the 'Kogakuha(古學派)'. The doctrines of Chu-tzu(朱子學) has hold absolute authority over the history of the oriental political thoughts. But the authority have gone through the stage of disorganization in a unique space called Eto(江戶) era of Japan. Therefore, the interpretations and concept establishments in a new dimension are naturally formed in that periods about 'Min(民)=People'. Based on discussions like this, the purpose of this paper is to study how those movements are emerged in what kinds of thinking and debating process. In part of Ito-Jinsai, this paper have reconsidered the concept of 'People' which Jinsai had thought and examined closely with critical mind about 'In(仁)=Mercy'. In case of Ogyu-Sorai, this paper have argued his political theory of 'the welfare of the people in the nation(安民天下)', in clarifying with the concept of 'the Roads of the Saint(先王의 道)' and the meaning about his declaration that "the Six Scripture(六經) is things(物)". The meaning of political view of this two philosopher is in the point to suggest some kinds of cure for problems of those days with the former days values. In the Jinsai's doctrine, that cure is 'the realization of the rule of right(王道)' based on new interpretation of 'Mersy'. And in case of Sorai, that is a form of independence of politics from morality based on 'the Roads of the Saint'.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.38 no.4
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• pp.1-11
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• 2020

Noksan is a green area in the form of a hill located inside Gyeongbokgung Palace, unrecognized as a cultural heritage space. This study analyzed the literature and the actual site to derive its landscape meaning by examining the background for the formation of Noksan and how it changed. As a result, the identity of Noksan was related to the geomagnetic vein, pine forest, and deers, and the following are its landscape meaning. First, several ancient maps, including the 「Map of Gyeongbokgung Palace」 depicted the mountain range continuing from Baegaksan(Bugaksan) Mountain to areas inside Gyeongbokgung Palace, and Noksan is a forest located on the geomantic vein, which continues to Gangnyeongjeon Hall and Munsojeon Hall. On Bukgwoldo(Map of Gyeongbokgung Palace), Noksan is depicted with Yugujeong Pavilion, Namyeogo Storage, office for the manager of Noksan, the brook on north and south, and the wall. It can be understood as a prototypical landscape composed of minimal facilities and the forest. Second, the northern palace walls of Gyeongbokgung Palace were constructed in King Sejong's reign. The area behind Yeonjo(king's resting place) up to Sinmumun Gate(north gate of the palace) was regarded as the rear garden when Gyeongbokgung Palace was constructed. However, a new rear garden was built outside the Sinmumun Gate when the palace was rebuilt. Only Noksan maintained the geomantic vein under the circumstance. However, the geographical features changed enormously during the Japanese colonial era when they constructed a huge official residence in the rear garden outside the Sinmumun Gate and the residence of the governor-general and road in the site of the Blue House. Moreover, Noksan was severed from the foothill of Baegaksan Mountain when 'Cheongwadae-ro(road)' was constructed between the Blue House and Noksan in 1967. Third, the significant characteristics and conditions of the forest, which became the origin of Noksan, were identified based on the fact that the geomatic state of the northeastern side of Gyeongbokgung Palace, the naecheongnyong area in geomantic terms(the innermost 'dragon vein' among the veins that stretched out from the central mountain toward the left side), and they planted pine trees to reinforce the 'ground vein' and the fact that it was expressed as the 'Pine Field' before the Japanese Invasion of Korea in 1592. The pine forest, mixed with oaks, cherries, elms, and chestnuts, identified through the excavation investigation, can be understood as the original vegetation landscape. Noksan's topography changed; a brook disappeared due to mounding, and foreign species such as acacia and ornamental juniper were planted. Currently, pine trees' ratio decreased while the forest is composed of oaks, mixed deciduous trees, some ailanthus, and willow. Fourth, the fact the name, 'Noksan,' came from the deer, which symbolized spirit, longevity, eternal life, and royal authority, was confirmed through an article of The Korea Daily News titled 'One of the seven deers in Nokwon(deer garden) in Gyeongbokgung Palace starved to death.'

• Communications of Mathematical Education
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• v.35 no.2
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• pp.173-191
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• 2021

This study noted that a survey of teachers in a leading study conducted in Korea during the Pandemics period pointed out that the "real-time interactive" classes account for a significantly small portion of the remote class format. Contentually, the study reported cases of developing and applying "real-time interactive" class materials based on "planar decision requirements" of high school mathematics subject geometry. The teacher who participated in the development was a math teacher who worked at a Seoul-based high school with 28 years of high school teaching experience, and a teacher who was in charge of geometry in the math department in 2020. The development teacher decided to develop real-time interactive classes. In particular, the materials were developed by organizing the class guidance plan in four stages: 'Meeting and Class Guidance', 'Giving motivation', 'Suggesting tasks', 'Individual Investigative Activities and Teacher Feedback' and 'Reflection and Evaluation' which were selected through the process of selecting the class contents and selecting online class tools. At this time, the development teacher produced and presented about five minutes of video material using the videooscribe, a whiteboard animation program. And in case of task number 8, it consisted of recording the students' free thoughts after class, which served as a role of assessment by students themselves and providing feedback to their teachers. This study is a case study that introduces a series of courses in which field teachers develop class materials, and in addition to presenting class materials that can be applied directly to classes, is a result of a study that focuses on the role of presenting samples for future class data development. The materials developed were verified as class materials based on the opinions of the students who participated in the class and the results of the evaluation commissioned by the three math teachers.

• Korean Journal of Heritage: History & Science
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• v.54 no.1
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• pp.206-219
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• 2021

The warming of the climate is increasing the damage caused by termites to wooden buildings, cultural properties and houses. A group removal system can be installed around the building to detect and remove termite damage; however, if the site is not visited regularly, every one to two months, you cannot observe whether termites have spread within, and it is difficult to take prompt effective action. In addition, since the system is installed and operated in an exposed state for a long period of time, it may be ineffective or damaged, resulting in a loss of function. Furthermore if the system is installed near a cultural site, it may affect the aesthetic environment of the site. In this study, we created a detection system that uses wood, cellulose, magnets, and magnetic sensors to determine whether termites have entered the area. The data was then transferred to a low power LoRa Network which displayed the results without the necessity of visiting the site. The wood was made in the shape of a pile, and holes were made from the top to the bottom to make it easier for termites to enter and produce a cellulose sample. The cellulose sample was made in a cylindrical shape with a magnet wrapped in cellulose and inserted into the top of a hole in the wood. Then, the upper part of the wood pile was covered with a stopper to prevent foreign matter from entering. It also served to block external factors such as light and rainfall, and to create an environment where termites could add cellulose samples. When the cellulose was added by the termites, a space was created around the magnet, causing the magnet to either fall or tilt. The magnetic sensor inside the stopper was fixed on the top of the cellulose sample and measured the change in the distance between the magnet and the sensor according to the movement of the magnet. In outdoor experiments, 11 cellulose samples were inserted into the wood detection system and the termite inflow was confirmed through the movement of the magnet without visiting the site within 5 to 17 days. When making further improvements to the function and operation of the system it in the future, it is possible to confirm that termites have invaded without visiting the site. Then it is also possible to reduce damage and fruiting due to product exposure, and which would improve the condition and appearance of cultural properties.

• Korean Journal of Mineralogy and Petrology
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• v.34 no.1
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• pp.31-40
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• 2021

The hydrogen in nominally anhydrous mineral is known to be associated with lattice defects, but it also can exist in the form of water and hydroxyl groups on the large surface of the nanoscale particles. In this study, we investigate the effectiveness of 1H solid-state nuclear magnetic resonance (NMR) spectroscopy as a robust experimental method to quantify the hydrogen atomic environments of amorphous silica nanoparticles with varying relative humidity. Amorphous silica nanoparticles were packed into NMR rotors in a temperature-humidity controlled glove box, then stored in different atmospheric conditions with 25% and 70% relative humidity for 2~10 days until 1H NMR experiments, and a slight difference was observed in 1H NMR spectra. These results indicate that amount of hydrous species in the sample packed in the NMR rotor is rarely changed by the external atmosphere. The amount of hydrogen atom, especially the amount of physisorbed water may vary in the range of ~10% due to the temporal and spatial inhomogeneity of relative humidity in the glove box. The quantitative analysis of 1H NMR spectra shows that the amount of hydrogen atom in amorphous silica nanoparticles linearly increases as the relative humidity increases. These results imply that the sample sealing capability of the NMR rotor is sufficient to preserve the hydrous environments of samples, and is suitable for the quantitative measurement of water content of ultrafine nominally anhydrous minerals depending on the atmospheric relative humidity. We expect that 1H solid-state NMR method is suitable to investigate systematically the effect of surface area and crystallinity on the water content of diverse nano-sized nominally anhydrous minerals with varying relative humidity.

• KIPS Transactions on Software and Data Engineering
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• v.11 no.1
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• pp.41-50
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• 2022

In this paper, a method to directly calculate the major elements of skin color such as melanin and hemoglobin from the RGB signal of the camera is proposed. The main elements of skin color typically measure spectral reflectance using specific equipment, and reconfigure the values at some wavelengths of the measured light. The values calculated by this method include such things as melanin index and erythema index, and require special equipment such as a spectral reflectance measuring device or a multi-spectral camera. It is difficult to find a direct calculation method for such component elements from a general digital camera, and a method of indirectly calculating the concentration of melanin and hemoglobin using independent component analysis has been proposed. This method targets a region of a certain RGB image, extracts characteristic vectors of melanin and hemoglobin, and calculates the concentration in a manner similar to that of Principal Component Analysis. The disadvantage of this method is that it is difficult to directly calculate the pixel unit because a group of pixels in a certain area is used as an input, and since the extracted feature vector is implemented by an optimization method, it tends to be calculated with a different value each time it is executed. The final calculation is determined in the form of an image representing the components of melanin and hemoglobin by converting it back to the RGB coordinate system without using the feature vector itself. In order to improve the disadvantages of this method, the proposed method is to calculate the component values of melanin and hemoglobin in a feature space rather than an RGB coordinate system using a feature vector, and calculate the spectral reflectance corresponding to the skin color using a general digital camera. Methods and methods of calculating detailed components constituting skin pigments such as melanin, oxidized hemoglobin, deoxidized hemoglobin, and carotenoid using spectral reflectance. The proposed method does not require special equipment such as a spectral reflectance measuring device or a multi-spectral camera, and unlike the existing method, direct calculation of the pixel unit is possible, and the same characteristics can be obtained even in repeated execution. The standard diviation of density for melanin and hemoglobin of proposed method was 15% compared to conventional and therefore gives 6 times stable.