• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.6
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• pp.496-505
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• 2020

In the previous research, the effectiveness of resonator was confirmed through the numerical analysis on two cases with the use of existing resonator at the Mukho and Imwon ports located in the eastern coast of South Korea by discussing the reduction rates of 1983 Central East Sea tsunami, and 1993 Hokkaido Southwest off tsunami, respectively. In this study, the reduction rates of tsunami height with three different resonators, Type I, II-1, and II-2, at the Samcheok port were examined respectively through the numerical analysis using COMCOT model under the same condition as the previous study. It was discussed the spatial distribution of maximum height of tsunami, change of water level, and effectiveness of resonator with the presence of new types of resonator, and change of their sizes. As a result, the effectiveness of resonator was verified through the application of new types of resonator reducing about maximum 40% of tsunami height. In order to design the optimal resonator for the variety of site condition, it is necessary to research about the various cases applying different shape, arrangement, and size of resonator as further study.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.46 no.4
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• pp.371-382
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• 2020

There have been continuous attempts to quantify sensory attributes of cosmetic products by measuring relevant physical properties. The most representative method to evaluate stickiness is to measure axial force using texture analyzer. Stickiness is known to correlate with AUC which abbreviates area under curve in the obtained axial force curve as a function of time. Recently, Normandie University research group developed in vivo stickiness evaluation method considering the characteristics of skin along with established evaluation method[8]. Based on the study, we tried to optimize in vivo stickiness evaluation method especially for cosmetic creams. The experiment was carried out on 5 different facial creams products by changing the amount and the times of rolling of creams, and the shape and material of probes. Based on the results of the sensory evaluation, the most consistent conditions were established as the optimal evaluation method. As a result, applying 70 μL of cream and rubbing 10 times for 7 s inside the 3.4 cm circle were judged to be suitable. As for the probes, spherical metallic probe was more proper due to its reproducibility. We conducted the settled method on 10 subjects to check its validity. Although the absolute values of AUC differed depending on the individuals, the AUC values were all ranked the same. Finally, for the standardization of stickiness of AUC, polyvinylpyrrolidone (PVP) was set as a reference material and we measured AUC of its aqueous solution by changing concentration. Then, the degree of stickiness recognition for 5 different creams was surveyed to check the correlation between AUC and stickiness.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.4
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• pp.255-262
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• 2021

In this study, a jointless bridge that integrates the superstructure and abutment without installing an expansion joint was analyzed. An example of a jointless bridge that has been introduced in Korea since 2009. Owing to the short period of use and lack of experience in design, construction, and maintenance, there is insufficient information regarding the long-term behavior of jointless bridges. When analyzing numerous bridges, the numerical analysis model must maintain the numerical values used and ensure the convenience of model construction. In this study, sensitivity analysis was performed to select a numerical model for various types of jointless bridges using commercial finite element programs, MIDAS Civil and ABAQUS 2018. According to a solid element-based model, we analyzed the mean and maximum relative errors between structural models. Consequently, it was found that the beam element-based model exhibits a significantly small relative error in comparison to the shell element, where a relatively large error was recorded. Therefore, the optimal numerical analysis model, a practical model that maintains the similarity and precision of the displacement shape cause by relative error, was judged to be the most suitable for jointless bridges based on the shell element.

• Korean Journal of Remote Sensing
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• v.37 no.4
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• pp.699-717
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• 2021

South Korea is pushing for the advancement of crop production technology to achieve food self-sufficiency and meet the demand for safe food. A medium-sized satellite for agriculture is being launched in 2023 with the aim of collecting and providing information on agriculture, not only in Korea but also in neighboring countries. The satellite is to be equipped with various sensors, though reference data for ground information are lacking. Hyperspectral remote sensing combined with 1st derivative is an efficient tool for the identification of agricultural crops. In our study, we develop a system for hyperspectral analysis of the ground-based reflectance spectrum, which is monitored seven times during the cultivation period of three soybean crops using a PSR-2500 hyperspectral sensor. In the reflection spectrum of soybean canopy, wavelength variations correspond with stages of soybean growths. The spectral reflection characteristics of soybeans can be divided according to growth into the vegetative (V)stage and the reproductive (R)stage. As a result of the first derivative analysis of the spectral reflection characteristics, it is possible to identify the characteristics of each wavelength band. Using our developed monitoring system, we observed that the near-infrared (NIR) variation was largest during the vegetative (V1-V3) stage, followed by a similar variation pattern in the order of red-edge and visible. In the reproductive stage (R1-R8), the effect of the shape and color of the soybean leaf was reflected, and the pattern is different from that in the vegetative (V) stage. At the R1 to R6 stages, the variation in NIR was the largest, and red-edge and green showed similar variation patterns, but red showed little change. In particular, the reflectance characteristics of the R1 stage provides information that could help us distinguish between the three varieties of soybean that were studied. In the R7-R8 stage, close to the harvest period, the red-edge and NIR variation patterns and the visible variation patterns changed. These results are interpreted as a result of the large effects of pigments such as chlorophyll for each of the three soybean varieties, as well as from the formation and color of the leaf and stem. The results obtained in this study provide useful information that helps us to determine the wavelength width and range of the optimal band for monitoring and acquiring vegetation information on crops using satellites and unmanned aerial vehicles (UAVs)

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.7
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• pp.445-454
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• 2022

Ice accretion on the aircraft components, such as wings, fuselage, and empennage, can occur when the aircraft encounters a cloud zone with high humidity and low temperature. The prevention of ice accretion is important because it causes a decrease in the aerodynamic performance and flight stability, thus leading to fatal safety problems. In this study, a shape design optimization of a multi-element airfoil is performed to minimize the amount of ice accretion on the high-lift device including leading-edge slat, main element, and trailing-edge flap. The design optimization framework proposed in this paper consists of four major parts: air flow, droplet impingement and ice accretion simulations and gradient-free optimization algorithm. Reynolds-averaged Navier-Stokes (RANS) simulation is used to predict the aerodynamic performance and flow field around the multi-element airfoil at the angle of attack 8°. Droplet impingement and ice accretion simulations are conducted using the multi-physics computational analysis tool. The objective function is to minimize the total mass of ice accretion and the design variables are the deflection angle, gap, and overhang of the flap and slat. Kriging surrogate model is used to construct the response surface, providing rapid approximations of time-consuming function evaluation, and genetic algorithm is employed to find the optimal solution. As a result of optimization, the total mass of ice accretion on the optimized multielement airfoil is reduced by about 8% compared to the baseline configuration.

• Journal of Industrial Convergence
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• v.20 no.10
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• pp.33-38
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• 2022

In this paper, a simple method of forming a solution-based carbon nanotube (CNT) for use as a conductive material for electronic devices was studied. The CNT thin film coating was performed on the glass by applying the spin coating method and the argon atmospheric pressure plasma process. In order to observe changes in electrical and physical properties according to the number of coatings, samples formed in the same manner from times 1 to 5 were prepared, and surface shape, reflectance, transmittance, absorbance, and sheet resistance were measured for each sample. As the number of coatings increased, the transmittance decreased, and the reflectance and absorptivity increased in the entire measurement wavelength range. Also, as the wavelength decreases, the transmittance decreases, and the reflectance and absorption increase. In the case of electrical properties, it was confirmed that the conductivity was significantly improved when the second coating was applied. In conclusion, in order to replace CNT with a transparent electrode, it is necessary to consider the number of coatings in consideration of reflectivity and electrical conductivity together, and it can be seen that 2 times is optimal.

• Journal of Biomedical Engineering Research
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• v.43 no.5
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• pp.341-352
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• 2022

Medical image segmentation is the most important task in radiation therapy. Especially, when segmenting medical images, the liver is one of the most difficult organs to segment because it has various shapes and is close to other organs. Therefore, automatic segmentation of the liver in computed tomography (CT) images is a difficult task. Since tumors also have low contrast in surrounding tissues, and the shape, location, size, and number of tumors vary from patient to patient, accurate tumor segmentation takes a long time. In this study, we propose a method algorithm for automatically segmenting the liver and tumor for this purpose. As an advantage of setting the boundaries of the tumor, the liver and tumor were automatically segmented from the CT image using the 2D CoordConv DeepLab V3+ model using the CoordConv layer. For tumors, only cropped liver images were used to improve accuracy. Additionally, to increase the segmentation accuracy, augmentation, preprocess, loss function, and hyperparameter were used to find optimal values. We compared the CoordConv DeepLab v3+ model using the CoordConv layer and the DeepLab V3+ model without the CoordConv layer to determine whether they affected the segmentation accuracy. The data sets used included 131 hepatic tumor segmentation (LiTS) challenge data sets (100 train sets, 16 validation sets, and 15 test sets). Additional learned data were tested using 15 clinical data from Seoul St. Mary's Hospital. The evaluation was compared with the study results learned with a two-dimensional deep learning-based model. Dice values without the CoordConv layer achieved 0.965 ± 0.01 for liver segmentation and 0.925 ± 0.04 for tumor segmentation using the LiTS data set. Results from the clinical data set achieved 0.927 ± 0.02 for liver division and 0.903 ± 0.05 for tumor division. The dice values using the CoordConv layer achieved 0.989 ± 0.02 for liver segmentation and 0.937 ± 0.07 for tumor segmentation using the LiTS data set. Results from the clinical data set achieved 0.944 ± 0.02 for liver division and 0.916 ± 0.18 for tumor division. The use of CoordConv layers improves the segmentation accuracy. The highest of the most recently published values were 0.960 and 0.749 for liver and tumor division, respectively. However, better performance was achieved with 0.989 and 0.937 results for liver and tumor, which would have been used with the algorithm proposed in this study. The algorithm proposed in this study can play a useful role in treatment planning by improving contouring accuracy and reducing time when segmentation evaluation of liver and tumor is performed. And accurate identification of liver anatomy in medical imaging applications, such as surgical planning, as well as radiotherapy, which can leverage the findings of this study, can help clinical evaluation of the risks and benefits of liver intervention.

• Journal of Mushroom
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• v.20 no.3
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• pp.147-152
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• 2022

To develop mushroom varieties for cultivating at low temperature on oak logs, a strain with a low fruiting body generation temperature was crossed with Di-mon to select for a line with excellent properties. Selection was followed by cultivation testing. From these studies, Heunghwa 1ho was identified. The optimum temperature for cultivating Heunghwa 1ho, was 13.3℃. The fruiting temperature range was 6.4~20.2℃, identical to that of the parent strain. Growth at 25℃ for 7 days achieved optimal mycelial growth of 61.9±2.10 mm, superior to growth of the parent strain at this temperature. The cap shape of Heunghwa 1ho was convex, cap diameter was 57.8±8.31 mm, and cap color was brown. Heunghwa 1ho showed similar genetic traits to those of the parental strain. However, dry weight (20.1 kg/m³) and cap diameter and color are superior to those of the parent strain. The 3 year fresh oak mushroom yield was 113.8 kg/m³, superior to the respective yields of the parent strains JMI 10047 and JMI 90021 (92.5 kg/m³ and 66.4 kg/m³).

• Korean Association of Arts Management
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• no.58
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• pp.49-88
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• 2021

Contemporary literary writers engage in multiple jobs and activities in the changing industrial and institutional environments to manage careers and produce literary value. The notion of art entrepreneurship envisages writers as the actors pursuing optimal rewards at both literary and economic levels by applying creative knowledge and skills to the management of career. In contrast, the notion of creative labor argues that writers go through career insecurity as they pursue self-fulfillment through work. This paper critically reviews two notions and suggests the notion of cultural intermediaries to better understand their production of literary value within the variety of relational contexts where they are situated. This paper analyzes the structures and characteristics of a wide range of intermediary practices by literary writers. Based on the analysis, I argue that the autonomy of literary value the writers construct and their status of entrepreneur-labourer are contingent upon the relational contexts within which they practice the intermediary work. I also suggest that literary writers by utilizing a variety of tactics cope with the changes that shape the autonomy of literature and invent new roles and identities as cultural intermediaries. Furthermore, literary writers develop not only self-management skills to adapt to the changing environments but also the collective capacity to cope with the constraints derived from the structural change of literary production and circulation. Finally, I argue that the art management discipline can reflect upon and support the creative endeavors of literary writers by embracing the critical understanding of structural changes suggested by the disciplines of humanities and social sciences.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.5
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• pp.24-31
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• 2021

The soundproof tunnels have been generally designed with H-beam girders, and the high weight of H-beam may cause the excessive design of the substructure. To solve this problem, this paper proposes a new soundproof tunnel girder design composed of pipes and discontinuous plates. First, the structural behavior of the straight girder according to the design parameters was examined through finite element analysis. The arrangement and shape of the plates were determined as the design parameter, to obtain the optimal design of girder. After then, the structural behavior and buckling stability of the arched girder were subsequently evaluated. As a result of the parameter analysis, it was confirmed that the axial force acting on the girder increased and the moment decreased as the ratio of unsupported sections decreased or the number of supporting plates increased. The stress concentration on the pipe member was relieved by increasing the long axis length of the elliptical plate. Arched girder analysis showed that the structural efficiency increase as the long axis of elliptical plate increase. As a result of the buckling evaluation, the buckling threshold load of the three connected girders was about 3.7 times higher than the design load. Consequently, it was confirmed that the proposed soundproof tunnel structure design satisfies both light weight and structural safety.