• Journal of the Society of Cosmetic Scientists of Korea
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• v.47 no.1
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• pp.49-56
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• 2021

In this study, a liquid crystal emulsion with a composition ratio similar to the skin lipid composition was manufactured using ceramide, glycolipids, cholesterol, and fatty acids, and a polarized microscope was used to identify liquid crystal particles in the formulation, and a cryso-SEM was used to confirm the formation of a multilayer structure. The above samples were stored at room temperature for one month and the liquid crystal structure was continuously maintained through microscopic observation. In addition, a cream composition containing liquid crystal emulsion was manufactured, and the efficiency of ceramide skin penetration was confirmed using three-dimensional artificial skin. Clinical trials were conducted using the cream composition and the results of clinical trials on skin barrier improvement were confirmed by measuring skin moisture retention (skin hydration) and transepidermal water loss (T EWL) of subjects compared to general emulsion.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.1
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• pp.59-69
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• 2021

Recently, large-scale offshore and coastal structures have been constructed owing to the increasing interest in eco-friendly energy development. To achieve this, precise simulations of waves are necessary to ensure the safe operations of marine structures. Several experiments are required in the field to understand the offshore wave; however, in terms of scale, it is difficult to control variables, and the cost is significant. In this study, numerical waves under various wave conditions are produced using a piston-type wavemaker, and the produced wave profiles are verified by comparing with the results from a numerical wave tank (NWT) modeled using the smoothed particle hydrodynamics (SPH) method and theoretical equations. To minimize the effect by the reflected wave, a mass-weighted damping zone is set at the right end of the NWT, and therefore, stable and uniform waves are simulated. The waves are generated using the linear and Stokes wave theories, and it is observed that the numerical wave profiles calculated by the Stokes wave theory yield high accuracy. When the relative depth is smaller than two, the results show good agreement irrespective of the wave steepness. However, when the relative depth and wave steepness are larger than 2 and 0.04, respectively, the errors are negligible if the measurement position is close to the excitation plate. However, the error is 10% or larger if the measurement position is away from the excitation location. Applicable target wave ranges are confirmed through various case studies.

• Journal of the Korea Computer Graphics Society
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• v.27 no.5
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• pp.63-71
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• 2021

Among drone autonomous flight technologies, obstacle avoidance is a very important technology that can prevent damage to drones or surrounding environments and prevent danger. Although the LiDAR sensor-based obstacle avoidance method shows relatively high accuracy and is widely used in recent studies, it has disadvantages of high unit price and limited processing capacity for visual information. Therefore, this paper proposes an obstacle avoidance algorithm for drones using camera-based PPO(Proximal Policy Optimization) reinforcement learning, which is relatively inexpensive and highly scalable using visual information. Drone, obstacles, target points, etc. are randomly located in a learning environment in the three-dimensional space, stereo images are obtained using a Unity camera, and then YOLov4Tiny object detection is performed. Next, the distance between the drone and the detected object is measured through triangulation of the stereo camera. Based on this distance, the presence or absence of obstacles is determined. Penalties are set if they are obstacles and rewards are given if they are target points. The experimennt of this method shows that a camera-based obstacle avoidance algorithm can be a sufficiently similar level of accuracy and average target point arrival time compared to a LiDAR-based obstacle avoidance algorithm, so it is highly likely to be used.

• The Journal of the Acoustical Society of Korea
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• v.40 no.6
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• pp.555-565
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• 2021

The goal of this study is to improve flow and noise performances of existing backward-curved blade centrifugal fan system used for circulating cold air in a refrigerator freezer by optimally designing airfoil shape. The unique characteristics of the system is to drive cold airflow with two volute tongues in combination with duct system in a back side of a refrigerator without scroll housing generally used in a typical centrifugal fan system. First, flow and noise performances of existing fan system were evaluated experimentally. A P-Q curve was obtained using a fan performance tester in the flow experiment, and noise spectrum was measured in an anechoic chamber in the noise experiment. Then, flow characteristics were numerically analyzed by solving the three-dimensional unsteady Navier-Stokes equations and noise analysis was performed by solving the Ffowcs Williams and Hawkins equation with input from the flow simulation results. The validity of numerical results was confirmed by comparing them with the measured ones. Based on the verified numerical method, blade inlet and outlet angles were optimized for maximum flow rate using the two-factor central composite design of the response surface method. Finally, the flow and noise performances of a prototype manufactured with the optimum design were experimentally evaluated, which showed the improvement in flow and noise performance.

• Journal of the Korean Society for Library and Information Science
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• v.57 no.2
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• pp.151-178
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• 2023

The purpose of this study is to investigate the effect of school library reading classes on the convergence literacy of adolescents based on the convergence reading education model. To achieve this, elements of convergence education for future-oriented competence were derived from the level of reading education based on previous studies and literature, and the effectiveness of education was measured by conducting a convergence literacy test targeting 50 general high school students. In this study, reading classes and tests were conducted over 12 sessions from April 2022 to November 2022, and the study participants were divided into two groups, and convergence reading education and self-reading education were applied respectively. The analysis results of this study are as follows. First, It was verified that there was a significant difference in the promotion of convergent literacy of adolescents according to the method of reading education. Second, it was verified that convergence reading education had a significant effect on convergence literacy of adolescents such as convergence, creativity, self-direction and communication ability. Third, as a result of verifying whether learning motivation plays a mediating role in convergence reading education influencing convergent literacy, learning motivation played a partial mediating role and had an indirect effect on creativity, self-direction, and communication ability between convergence reading education and convergence literacy, but showed no significant mediating effect on convergence ability.

• The Journal of the Acoustical Society of Korea
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• v.43 no.1
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• pp.95-102
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• 2024

Due to technological advances, the cruising speed of high-speed trains is increasing, and aerodynamic noise generated from the flow outside the train has been an important consideration in the design stage. To accurately predict the flow-induced noise, high-resolution generation of sound sources in the near field and low-dissipation of sound propagation in the far field are required. This should be accompanied by a numerical grid and time resolution that can properly consider both temporal and spatial scales for each component of the real high-speed train. To overcome these challenges, this research simultaneously calculates the external flow and acoustic fields of five high-speed train cars of real-scale and at operational running speeds using a threedimensional unsteady Large Eddy Simulation technique. To verify the numerical analysis, the measurements of the wall pressure fluctuation and numerical results are compared. The Ffowcs Williams and Hawking equation is used to predict the acoustic power radiated from the high-speed train. This research is expected to contribute to noise reduction based on the analysis of the aerodynamic noise generation mechanism of high-speed trains.

• Journal of the Korea Society of Computer and Information
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• v.29 no.3
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• pp.199-216
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• 2024

This research examines the factors influencing consumer purchase intentions in e-commerce live streaming, set against the backdrop of the internet celebrity economy. The investigation serves as a pivotal inquiry into the dynamics of this economy, striving to uncover the extent of internet celebrities' influence, particularly in terms of their economic impact. Employing the Emotional Behavioral Cognitive (ABC) attitude theory and the Stimulus Organism Response (S-O-R) theory as foundational frameworks, this study scrutinizes internet celebrity live streaming sales. It incorporates direct observations and leverages existing scholarly work to devise a tailored measurement scale and questionnaire. From this, a research model and hypotheses are developed, leading to the establishment of an empirical model. This empirical model is instrumental in statistically analyzing how e-commerce live streaming, within the internet celebrity economy context, shapes consumer purchase intentions. By integrating theoretical insights and empirical findings, the research elucidates the strategic dimensions and consumer behavior aspects in digital commerce. It enhances understanding of how internet celebrity influence intersects with consumer purchasing processes. Overall, this study contributes to the academic discourse on digital marketing and consumer behavior, providing a nuanced perspective on the mechanisms through which internet celebrities affect e-commerce. It offers valuable implications for marketers, strategists, and policymakers aiming to navigate the complex landscape of the internet celebrity economy.

• Korean Journal of Hospice Care
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• v.7 no.1
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• pp.5-14
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• 2007

Objective : This study was done to identify the status of Spiritual Well-Being in Nursing Students and to investigate the correlation between related various characteristics and Spiritual Well-Being and to provide baseline data for ride school-life and development of Spiritual-education program for nursing students. Method : The data was collected from 188 christian Nursing students by using questionary method. they are all all agreed to participate in this study. Their Spiritual Well-Being were measured using Spiritual Well-Being scale developed by Paloutzian & Ellison(1983) and translated by Choi(1990) and reversed by Kang(1996). Results : The data was analyzed by using SPSS/PC+12.0. The summary of results were as follows; 1. The mean score of Spiritual Well-Being were $63.95\pm10.256$(range from 20-80) 2. There were significant differences between the grade(F=6.101, p= .001), type of religion(F= 17.703, p= .000), In Christian, the level of devotee(F=8.194, p= .000), duration of church attendance(F=7.947, p= .000), regular attendance of chapel(F=4.242, p= .000), regular reading(study) of Bible and prayer (F=5.863, p= .001=0). perceived personal encounter with Jesus(F=4.160, p= .000), religion of parent(F=9.320, p= .000), perceived attitude of parenting(F=4.146, p= .000), hope to admit/transfer to other course or not(F=-2.050, p= .050). Conclusion : Our results were valuable to provide basic guidelines for ride school-life and for the development of Spiritual-education program for Nursing students.

• Journal of Life Science
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• v.22 no.7
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• pp.920-927
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• 2012

The objective of this research was to develop the functional material of water and 60% ethanol extracts from nine kinds of mulberry fruits (Morus alba L.) that influence the inhibitory activity on angiotensin-converting enzyme, xanthine oxidase, ${\alpha}$-amylase, and ${\alpha}$-glucosidase. The total phenolic contents in the water extracts were over 2 mg/g in two species (Cheongilppong and Kangwon III) and five species (Daeyoupchosaeng, Cheongilppong, Kangwon III, Hihak, and Cataneo) of 60% ethanol extracts. The inhibitory activity against the angiotensin-converting enzyme was determined with them. Baekwoon III was $90.9{\pm}4.5%$ in the water extracts, and Hihak was $81.8{\pm}4.5%$ in the 60% ethanol extracts. The inhibitory activity of Kuksang 20 against xanthin oxidase was about 10% in the water extracts, and Cataneo was $21.4{\pm}2.3%$ in the 60% ethanol extracts. Six of the species (Daeyoupchosaeng, Suwonppong, Cheongilppong, Kangwon III, Hihak, and Kuksang 20) in the water extracts showed inhibitory activities against ${\alpha}$-amylase, as 100%, respectively. The inhibitory activity of ${\alpha}$-glucosidase was determined for these nine species. Four species (Baekwoon III, Daeyoupchosaeng, Cheongilppong, Kangwon III, Hihak, and Kuksang 20) in the water extracts and three species (Daechoukmyeun, Kangwon III, and Kuksang 20) in the 60% ethanol extracts showed inhibition of over 20%. The results revealed strong biological activity in spite of little total phenolic contents. These water and 60% ethanol extracts with high-quality biological activity from various mulberry fruits (Morus alba L.) are expected to represent good candidates for the development of antihypertentive and antidiabetes sources.

• Korean journal of food and cookery science
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• v.18 no.4
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• pp.399-406
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• 2002

Steam cakes were prepared with the addition of pine needle powder(Pinus densiflora Seib. et Zucc) at 0%, 1%, 2%, 3%, 4%, and their sensory quality and mechanical characteristics were compared. Sensory evaluation was performed and compared between the subjects in twenties and forties of age. As a result of the sensory evaluation in forties, steam cake with 3% pine needle powder showed the highest score in overall acceptability; however, in the group of twenties, control cake with no pine needle powder showed the highest score. In the measurement of color changes, L value(lightness) was decreased, but a value(redness) and b value(yellowness) were increased as the addition of pine needle powder increased. In textural characteristics, the hardness, springiness, gumminess and brittleness of steam cake were decreased by the increase of pine needle powder. The hardness and brittleness were increased as the storage time increased.