• Journal of Technologic Dentistry
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• v.42 no.4
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• pp.321-325
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• 2020

Purpose: This study is to evaluate the accuracy of gypsum replica models made from various gypsum products. Methods: One main model was made of stainless steel by CNC milling process. Molds were formed from the main model, and the gypsum replica models were made using 8 types of type IV gypsum, 10 pieces each. The main model was digitized by a contact scanner (Incise; Renishaw) and the gypsum replicas were digitized by an optical scanner (E4; 3Shape A/S). The difference between the main model and the gypsum replicas were measured by inspection software (3D Systems). One-way ANOVA was performed to evaluate the statistical significance of differences between groups. In addition, the independent sample T test was performed to determine the difference between the conventional and scannable stone group (n=10, α=0.05). Results: The root mean square of the stone models were 7.24 ㎛ to 10.78 ㎛, and statistical significance was found between the two groups (SR, FR) and the other 6 groups (IS, SG, CA, CS, ER, EBG) (p<0.05). The accuracy of the gypsum replicas was 9.04 ㎛ and 7.62 ㎛ in the conventional and scannable stone group, respectively. There was statistical significance between the two groups (p<0.01). Conclusion: In the limited results of this study, the product with low setting expansion and the scannable showed high accuracy. Therefore, in order to obtain a stable and accurate scan model, it is more effective in terms of accuracy to use a scannable stone with a low setting expansion.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.1
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• pp.45-50
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• 2021

Machines and facilities are physically or chemically degenerated by continuous usage. The representative type of the degeneration is the wearing of tools, which results in the process mean shift. According to the increasing wear level, non-conforming products cost and quality loss cost are increasing simultaneously. Therefore, a preventive maintenance is necessary at some point. The problem of determining the maintenance period (or wear limit) which minimizes the total cost is called the 'process mean shift problem'. The total cost includes three items: maintenance cost (or adjustment cost), non-conforming cost due to the non-conforming products, and quality loss cost due to the difference between the process target value and the product characteristic value among the conforming products. In this study, we set the production volume as a decreasing function rather than a constant. Also we treat the process variance as a function to the increasing wear rather than a constant. To the quality loss function, we adopted the Cpm+, which is the left and right asymmetric process capability index based on the process target value. These can more reflect the production site. In this study, we presented a more extensive maintenance model compared to previous studies, by integrating the items mentioned above. The objective equation of this model is the total cost per unit wear. The determining variables are the wear limit and the initial process setting position that minimize the objective equation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.11
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• pp.1551-1558
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• 2021

Beacon signals used in indoor positioning system are reflected and distorted, resulting in noise signals. KF(Kalman Filter) has been widely used to remove this noise. In order to apply the KF, optimization process considering the signal type, signal strength, and environmental elements of each product is required. In this paper, we propose a solution to the optimization problem of KF Parameters using GA(Genetic Algorithm) in BLE(Bluetooth Low Energy) Beacon-based indoor positioning system. After optimizing KF Parameters by applying the proposed technique with a certain distance between Beacon and receiver, we compared the estimated distance passed through KF with the unfiltered distance. The proposed technique is expected to reduce the time required and improve accuracy of KF Parameters optimization in an indoor positioning system based on RSSI (Received Signal Strength Indication).

• Journal of the Institute of Convergence Signal Processing
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• v.22 no.4
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• pp.199-205
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• 2021

The distributing board in directly installed on the ground or the bottom surface of the building, and when vibrations such as earthquakes or external shocks occur, the possibility of damage or malfunction of electric components such as internal power devices, wiring, and protection relays increases. Recently, the need for a seismic type distributing board is increasing, and research and development of a distributing board having a vibration damping function and product launch are being conducted. In this paper, an IoT-based data collection device system capable of measuring vibration and environmental data of distributing board was designed and implemented. When vibration occurred on the distributing board, data was stored and visualized in the MySQL DB through Node-RED for monitoring and data storage using the MQTT protocol for reliable messaging transmission. The test was conducted by attaching the IoT device of the distributing board, and data was collected in real-time and monitored through Node-RED.

• Biomolecules & Therapeutics
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• v.30 no.3
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• pp.291-297
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• 2022

Dry age-related macular degeneration (AMD) is a type of progressive blindness that is primarily due to dysfunction and the loss of retinal pigment epithelium (RPE). The accumulation of N-retinylidene-N-retinylethanolamine (A2E), a by-product of the visual cycle, causes RPE and photoreceptor degeneration that impairs vision. Genes associated with dry AMD have been identified using a blue light model of A2E accumulation in the retinal pigment epithelium and transcriptomic studies of retinal tissue from patients with AMD. However, dry macular degeneration progresses slowly, and current approaches cannot reveal changes in gene transcription according to stages of AMD progression. Thus, they are limited in terms of identifying genes responsible for pathogenesis. Here, we created a model of long-term exposure to identify temporally-dependent changes in gene expression induced in human retinal pigment epithelial cells (ARPE-19) exposed to blue light and a non-cytotoxic dose of A2E for 120 days. We identified stage-specific genes at 40, 100, and 120 days, respectively. The expression of genes corresponding to epithelial-mesenchymal transition (EMT) during the early stage, glycolysis and angiogenesis during the middle stage, and apoptosis and inflammation pathways during the late stage was significantly altered by A2E and blue light. Changes in the expression of genes at the late stages of the EMT were similar to those found in human eyes with late-stage AMD. Our results provide further insight into the pathogenesis of dry AMD induced by blue light and a novel model in vitro with which relevant genes can be identified in the future.

• Korean Journal of Community Nutrition
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• v.27 no.5
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• pp.373-386
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• 2022

Objectives: This study examined the perception of the vegan trend of millennials and their future needs. Methods: This study was conducted online from June 21, 2021, to July 15, 2021, targeting 425 adult men and women born between 1980 and 2000. The contents of the survey were divided into four categories: general information, awareness of vegetables, awareness of vegan trends, and future needs for vegan trends. Results: Most respondents recognized the importance of eating vegetables and perceived vegetarianism and veganism as a lifestyle. Regarding the perception of the vegan trend, the highest response rate was 'The vegan trend is to be satisfied with my life regardless of other people', while the lowest response rate was 'The vegan trend is only a temporary fad'. The reasons for purchasing vegan products with high response rates were 'interest in the earth and environment', 'protection of animal rights', and 'thinking about health'. The type of vegan product wanted in the future was delicious food, and convenience level was in the order of 'completely cooked', 'half-cooked', and 'pre-processed'. Among the sustainable vegetarian types that millennials responded, 'semi-vegetarian', which can consume most animal products excluding red meat, showed the highest response rate. Conclusions: The positive perceptions about vegetables are expected to increase. Efforts should be made to develop convenient meals using vegetables and provide reasonable prices to expand vegetable intake.

• Knowledge Management Research
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• v.23 no.3
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• pp.153-171
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• 2022

With the global ESG management craze, domestic and foreign companies voluntarily declare sustainable management and actively respond by establishing strategies. The Financial Services Commission mandates the disclosure of sustainability reports representing ESG management sequentially and will expand to SMEs in the future. Information disclosure of sustainability reports is mainly done through international standards such as GRI, SASB, and TCFD, and many domestic companies use GRI Standards guidelines. This study examines the composition system of sustainability reports and compares public and private companies with GRI Standards to analyze sustainable management by type. This study revealed that public enterprises focused on social and labor, while private enterprises focused on the economy and environment through TF-IDF modeling. In addition, the electronic and information communication industries focused on product responsibility. Unlike previous studies that quantified and analyzed sustainability management according to grade, the current study analyzed sustainability reports, which are unstructured data. Therefore, the results of this study are expected to provide valuable theoretical and practical implications for researchers and supervisors interested in ESG management.

• Journal of Plant Biotechnology
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• v.49 no.3
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• pp.213-221
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• 2022

Wild garlic (Allium victorialis var. platyphyllum, AVVP) is a nontimber forest product used as an edible and medicinal vegetable. AVVP is usually propagated form offspring bulbs but it takes a long time to harvest. Using tissue culture technology could overcome this problem. This study investigated the optimal conditions for shoot multiplication, root growth, and plant growth by scooping AVVP bulbs. AVVP bulbs harvested from Ulleung Island, Korea, the main producer of AVVP, were surface-sterilized and used for in vitro propagation. Shoot multiplication was performed by the scooping method. More than five multiple shoots were induced from scooped tissue in Quoirin and Lepoivre (QL) medium containing plant growth regulators (PGRs); the maximum number of multiple shoots were induced from scooped tissue in QL medium containing 0.45 μM thidiazuron (TDZ) after 16 weeks of culture. Roots were induced directly at the base of the shoots in all treatments. In vitro rooting depended on the type of PGRs, and the best root-inducing treatment was QL medium containing 9.84 μM indole-3-butyric acid (IBA). Plants with in vitro roots were transferred to pots containing artificial soil and successfully acclimatized for 4 weeks. The acclimatized plants showed a survival rate of 80% after 20 weeks and gradually promoted growth depending on the acclimatization period. The results of this study will be of great help to AVVP dissemination through sustainable mass propagation.

• Natural Product Sciences
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• v.28 no.3
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• pp.143-152
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• 2022

In our study, sixteen known phenolic compounds, including quercetin (1), methyl gallate (2), caesalpiniaphenol C (3), 8S,8'S,7'R-(-)-lyoniresinol (4), 7,3',5'-trihydroxyflavanone (5), sappanchalcone (6), sappanone A (7), taxifolin (8), fisetin (9), fustin (10), (+)-catechin (11), brazilin (12), 3,4,5-trimethoxyphenyl β-ᴅ-glucopyranoside (13), 1-(2-methylbutyryl)phloroglucinol-glucopyranoside (14), (+)-epi-catechin (15), and astragalin (16) and one mixture of two conformers of protosappanin B (17/18) were isolated from the stems of Caesalpinia decapetala var. japonica. Their structures were elucidated based on a comparison of their physicochemical and spectral data with those of literature. To the best of our knowledge, this represents the first isolation of compounds 3, 4, 8, 9, and 10 from C. decapetala and compounds 13 and 14 from the Caesalpinia genus. All the isolated compounds were evaluated for their inhibitory effect against the α-glucosidase enzyme. Among them, two flavonols (1 and 9), one chalcone (6), and one homoisoflavanone (7) exhibited an inhibitory effect on α-glucosidase action with an IC₅₀ range value of 5.08-15.01 μM, stronger than that of the positive control (acarbose, IC₅₀ = 152.22 μM). Kinetic analysis revealed that compounds 1 and 9 showed non-competitive α-glucosidase inhibition, while the inhibition type was mixed for compounds 6 and 7.

• Current Photovoltaic Research
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• v.10 no.2
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• pp.56-61
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• 2022

Recently, the expansion of the domestic solar market due to the promotion of eco-friendly and alternative energy-related policies is promising, and it is expected to lead the high-efficiency/high-power module market based on M10 or larger cells to reduce LCOE, 540-560W, M12 based on M10 cells Compared to the existing technology with an output of 650-700W based on cells, it is necessary to secure competitiveness through the development of modules with 600W based on M10 cells and 750W based on M12 cells. For the development of high efficiency/high-power n-type bifacial, it is necessary to secure a lightweight technology and structure due to the increase in weight of the glass to glass module according to the large area of the module. Since the mechanical strength characteristics according to the large area and high weight of the module are very important, design values such as a frame of a new structure that can withstand the mechanical load of the Mechanical Load Test and the location of the mounting hole are required. In this study, a structural analysis design model was introduced to secure mechanical reliability according to the enlargement of the module area, and the design model was verified through the mechanical load test of the actual product. It can be used as a design model to secure the mechanical reliability required for PV modules by variables such as module area, frame shape, and the location and quantity of mounting holes of the structural analysis model verified. A relationship of output drop can be obtained.