• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.6
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• pp.94-103
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• 2018

The purpose of designing composite lattice structure which applied to launching vehicle and tactical missile body is to minimize the thickness and weight for applied load. It is usually made of carbon fiber; fabricating with filament winding process over silicon mold, and provided with a window opening for inspection purpose if necessary. In this paper compression test is conducted without window opening in lattice structure and preliminary FEA is carried out to confirm its accuracy. And then FEA is performed for the case of window opening to evaluate the soundness and the safety factor of the structure. We have calculated for two kinds of window shape; rectangular one and hexagonal one. And we have calculated safety factors of the lattice structure with window opening in every case based on failure strength of rib and knot with varying the thickness and location of the window for hexagonal shape. Through our investigation, we have found out the followings; (1) the hexagonal shaped window is shown higher safety factor than rectangular one, (2) a window in a certain location is shown higher safety factor than others, (3) although the soundness of window structure is improved as increasing its thickness, a window of a certain thickness is shown higher safety factor than others because of stress concentration.

• The Journal of Engineering Geology
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• v.29 no.2
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• pp.137-151
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• 2019

Geophysical exploration techniques are effective for monitoring changes in the ground condition around the excavation project to prevent subsidence risks during excavation work, therefore, improving analysis techniques is required for applying and supplementing various geophysical exploration technologies. In this study, a field-scale on-site test was conducted to detect possible ground subsidence hazards and areas of relaxation zone that may occur during excavation work and due to underground water level changes. In order to carry out the field test, a real-scale excavation test bed was constructed and the geophysical exploration methods, such as electrical resistivity survey and multi-channel analysis of surface wave (MASW) survey for urban sites condition, have researched for optimal geophysical exploration parameter, design and correlation analysis between the results by reviewing the validity of each individual geophysical exploration and modeling. The results of this study showed the impact of each geophysical exploration on the relaxation zone and, in particular, the location of the underground water surface and the effects of excavation were identified using electrical resistivity survey. Further research on modeling will be required, taking into account the effects of excavation and groundwater.

• Environmental and Resource Economics Review
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• v.28 no.1
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• pp.147-176
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• 2019

This paper uses research on the Levelized Cost of Electricity (LCOE) in South Korea to conduct a simulation analysis on the impact of nuclear power dependency and usage rates on the social costs of power generation. We compare the $7^{th}$ basic plan for long-term electricity supply and demand, which was designed to increase nuclear power generation, to the $8^{th}$ basic plan for long-term electricity supply and demand that decreased nuclear power generation and increased renewable energy generation in order to estimate changes in social costs and electricity rates according to the power generation mix. Our environmental generation mix simulation results indicate that social costs may increase by 22% within 10 years while direct generation cost and electricity rates based on generation and other production costs may increase by as much as 22% and 18%, respectively. Thus we confirm that the power generation mix from the $8^{th}$ basic plan for long-term electricity supply and demand compared to the $7^{th}$ plan increases social costs of generation, which include environmental external costs.

• Journal of the Korean Institute of Landscape Architecture
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• v.46 no.6
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• pp.1-16
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• 2018

The decline in the construction industry has led to a decrease the profitability of small and medium-sized landscape contractors. To relieve this situation, small and medium-sized landscape contractors have continued to proactively find ways to enter global construction markets. However, many small and medium-sized landscape contractors face risks due to their lack of capacity and insufficient preparations to extend the business abroad. Thus, this study aims to analyze the current condition of the Vietnamese construction market and the related risk factors. It then suggests strategies to improve the small and medium-sized landscape contractors' competitiveness in that market. We investigated the business climate and analyzed risk factors. Finally, we developed expansion strategies and conducted in-depth interviews with six overseas construction professionals. The study results first showed that efforts to improve infrastructure and the increased demand for housing in Vietnam will lead to more opportunities for small and medium-sized landscape contractors entering the Vietnamese construction market. However, changes in the Vietnamese business climate may act as a variable. Second, we found that small and medium-sized landscape contractors' risk factors are mainly related to laws and regulations, government finance, market fluctuations, public administration system, minimum wage increases, financing and bonds, contracting, trees and materials, and design errors. Finally, small and medium-sized landscape contractors are required to consider the following when seeking to enter the Vietnamese construction market: short-term strategy and mid-to-long-term strategy. This study will be used as the basis for small and medium-sized landscape contractors to plan to enter the Vietnamese construction market and to contribute to the expansion of the global construction market in the landscape industry.

• Journal of the Korean Geotechnical Society
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• v.35 no.7
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• pp.29-39
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• 2019

Load distributive compression anchors distribute the compressive stress in the grout and increase the pull-out capacity of the anchor by using multiple anchor bodies. In this anchor type, the spacing between the anchor bodies has a large influence on the stress in the grout. However, there are few researches about the spacing and there are no design standards. Therefore, the effect of the anchor body spacing on the grout stress was analyzed by performing finite element analyses. First, the applicability of the numerical modeling was verified by comparing with field test results of a compression anchor. Then, the parametric study was performed varying soil type, anchor body spacing, and load magnitude. The analysis results showed that the maximum compressive stress in the grout increased at the narrower spacing and the tensile stress developed at the wider spacing. Therefore, the optimum spacing was defined as the spacing, which prevents the superposition of compressive stresses and minimize the tensile stress. Finally, the optimum spacing was proposed according to the soil type and the load magnitude.

• Journal of Convergence for Information Technology
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• v.9 no.5
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• pp.55-64
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• 2019

The purpose of this study was to investigate levels of self-efficacy, nurse image, vocational identity, and clinical practice satisfaction, to examine relationships among them, and finally to investigate predictors affecting of clinical practice satisfaction in nursing students. The participants were 227 nursing students in D city who were surveyed in September 2018 using self-report questionnaires. Self-efficacy, nurse image, vocational identity, and clinical practice satisfaction were related positively among variables. In the multiple regression analysis, self-efficacy, nurse image, vocational identity, health condition, relationship with practical colleague and 'satisfaction of nursing students in patient's recognition of nursing students' were influential factors significantly associated with the clinical practice satisfaction. Those factors explained 17.9% of the clinical practice satisfaction of nursing students. The most important factors were 'satisfaction of nursing students in patient's recognition of nursing students' and nurse image. In order to improve clinical practice satisfaction of nursing students, whole nurses should consider helping nursing students and patients to build up positive nurse image.

• Science of Emotion and Sensibility
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• v.24 no.3
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• pp.41-60
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• 2021

The purpose of this research was to determine whether multimodal cues in an online shopping environment could enhance tactile consumer mental imagery, purchase intentions, and attitudes towards an apparel product. One limitation of online retail is that consumers are unable to physically touch the items. However, as tactile information plays an important role in consumer decisions especially for apparel products, this study investigated the effects of multimodal cues on overcoming the lack of tactile stimuli. In experiment 1, to explore the product, the participants were randomly assigned to four conditions; picture only, video without sound, video with corresponding sound, and video with discordant sound; after which tactile mental imagery vividness, ease of imagination, attitude, and purchase intentions were measured. It was found that the video with discordant sound had the lowest average scores of all dependent variables. A within-participants design was used in experiment 2, in which all participants explored the same product in the four conditions in a random order. They were told that they were visiting four different brands on a price comparison web site. After the same variables as in experiment 1, including the need for touch, were measured, the repeated measures ANCOVA results revealed that compared to the other conditions, the video with the corresponding sound significantly enhanced tactile mental imagery vividness, attitude, and purchase intentions. However, the discordant condition had significantly lower attitudes and purchase intentions. The dual mediation analysis also revealed that the multimodal cue conditions significantly predicted attitudes and purchase intentions by sequentially mediating the imagery vividness and ease of imagination. In sum, vivid tactile mental imagery triggered using audio-visual stimuli could have a positive effect on consumer decision making by making it easier to imagine a situation where consumers could touch and use the product.

• Korean Journal of Food Science and Technology
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• v.53 no.2
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• pp.174-180
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• 2021

The optimal recipe for manufacturing composite honey-based herbal pills mainly comprising Rubus coreanus powder (RCP), black mulberry powder (BMP), and vitamin C was investigated. Honey-based herbal pills were prepared by mixing these powders, binding them with honey, and then forming a round shape. The experiment was designed based on the D-optimal mixture design, which included 12 experimental points with one replicate for three independent variables as follows: RCP (10~35%), BMP (10~35%), and vitamin C (5~10%). In addition, the dependent variables (total phenolic and flavonoid content and antioxidant activity) were measured and used to optimize the manufacturing conditions. The results showed that high amounts of RCP were correlated with high total flavonoid content, whereas the addition of high amounts of vitamin C resulted in higher antioxidant activity. In conclusion, an optimized formulation for the honey-based herbal pill was found to contain 35% RCP, 10% BMP, and 10% vitamin C.

• Journal of Internet of Things and Convergence
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• v.6 no.4
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• pp.33-38
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• 2020

It was reported that a mobile application was designed to easily provide natural dyeing information such as natural dye related resources, colors and dyed fabrics in 2007. Since studies on the linkage, application, etc. between natural dye dyeing and IoT are still lacking, diversity of information on the change of dyeing pattern by natural dye dyeing is required. In this study, it was to construct dyeing information by natural dyes, e.g., Lithospermum erythrorhizon, on silk, which has been traditionally used as many fibers in Korea. The extraction of the dye from L. erythrorhizon was carried out under pH4. The dried root of L. erythrorhizon showed dark brownish purple. Silk fabric by a without a mordant typically showed a purple dyed pattern. In the staining by sodium tartrate plus citric acid, silk fabric was stained clear brown. Interestingly, the mordant of iron (II) sulfate, the silk fabric was dyed in a light gray color rather than black. When the mordant of aluminum potassium sulfate was treated with L. erythrorhizon-extracted dye, the results were almost the same as when the mordant was not treated. When the degree of dyeing was evaluated numerically, the treatment of the mordant of potassium dichromate was about 50% darker, and the dyeing by iron (II) sulfate was about 75% darker. These results will be helpful in the study of applying various dye colors using L. erythrorhizon, and it will provide information on dyeing controller and database system construction by dyeing parameters such as dyeing degree, pH concentration, and chromaticity change.

• Knowledge Management Research
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• v.21 no.4
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• pp.211-225
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• 2020

We investigate factors affecting chatbot use intention of online shopping mall users. We identify theoretical foundations from the literature and postulate that accuracy, personalization level, intelligence, intimacy, social presence, and piracy concern should affect intention to use more or negative intention to use. Based on 300 responses from online shopping mall chatbot users in Korea, we run the statistical analysis to assure the reliability and validity of the measurements. From the multiple regression analysis, we find that personalization level, intelligence, social presence, and privacy concerns significantly affect intention to use more. In contrast, we find that accuracy and privacy concerns significantly affect negative intention to use. This work will present pragmatic implications upon the design and management of chatbot in order to not only incent customers to use more but reduce factors that may cause negative use intention. Among functional factors, personalization and intelligence increases the intention to use more while accuracy decreases negative intention to use. Among emotional factors such as intimacy and social presence, we find that only social presence significantly increases intention to use more. Privacy concerns is found to decrease intention to use and increase negative intention to use.