• Journal of Navigation and Port Research
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• v.46 no.6
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• pp.554-561
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• 2022

Technology development related to maritime autonomous surface ships (MASS) is actively progressing around the world. However, since there are still many technically unresolved problems such as communication, cybersecurity, and emergency response capabilities, it is expected that it will take a lot of time for MASS to be commercialized. In this study, we proposed a ship group navigation system in which one leader ship and several follower ship are grouped into one group. In this system, when the leader ship begins to navigate, the follower ship autonomously follows the path of the leader ship. For path following, PD (proportional-derivative) control is applied. In addition, each ship navigates in a straight line shape while maintaining a safe distance to prevent collisions. Speed control was implemented to maintain a safe distance between ships. Simulations were performed to verify the ship group navigation system. The ship used in the simulation is the L-7 model of KVLCC2, which has related data disclosed. And the MMG (Maneuvering Modeling Group) standard method proposed by the Japan Society of Naval Architects and Ocean Engineering (JASNAOE) was used as a model of ship maneuvering motion. As a result of the simulation, the leader ship navigated along a predetermined route, and the follower ship navigated along the leader ship's path. During the simulation, it was found that the three ships maintained a straight line shape and a safe distance between them. The ship group navigation system is expected to be used as a navigation system to solve the problems of MASS.

• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.4
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• pp.81-93
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• 2022

There are many natural hot springs and mineral springs as well as the cultural heritage of the three kingdoms period in the Geum River basin including Chungcheong region. No specific regeneration and publicity plans for deteriorated facilities in this area has been presented. This study aims to suggest promising hot spots and complex water culture belt in the Chungcheong region and Geum River basin through the spatial interpretation of resources. The northern part of the Geum River basin is expected to become a therapeutic spring belt with many hot springs and CO₂-rich springs. In the central and southern parts of the Geum River basin, it is considered that it will be possible to promote convergence publicity by using groundwater resources and cultural assets.

• The Korea Journal of Herbology
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• v.33 no.2
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• pp.53-58
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• 2018

Objectives : Plantaginis asiaticae Folium (PA) has been widely used in Korean medicine for treatment of liver disease, stomach troubles and inflammation. We investigated the effect of PA on lipid accumulation in 3T3-L1 according to extraction conditions. Methods : The MTT assay was employed to evaluate the cytotoxicity of PA extracted by different solvents (water, 50% ethanol, and 95% ethanol) on 3T3-L1 preadipocytes. Oil red O staining was used to identify intracellular lipid accumulation in 3T3-L1. 3T3-L1 adipocytes were treated with PA at concentration ranging in 0.1, 0.2 and $0.4mg/m{\ell}$. PA was extracted by different extraction conditions such as extraction solvents, extraction time, and extraction temperature. In addition, UPLC analysis was used for determination of candidates of active ingredients in PA. Results : 3T3-L1 preadipocytes were treated with PA extracted by different solvents (water, 50% ethanol, and 95% ethanol) and there was no cytotoxicity. Oil red O staining was employed to identify the effect of PA on lipid accumulation in 3T3-L1. In the present study, PA water extraction at $70^{\circ}C$ for 6 hours decreased greatly in lipid accumulation. The range of concentrations was 0.1, 0.2 and $0.4mg/m{\ell}$. Concentration at $0.2mg/m{\ell}$ was the most effective one among them. Candidates of active ingredients in PA were shown plantamajoside and acteoside through UPLC. Conclusions : These results suggest that the effect of PA water extraction at $70^{\circ}C$ on lipid accumulation in 3T3-L1 is superior to other extraction conditions. We suppose that plantamajoside and acteoside may be candidates of active ingredients in PA.

• The Korea Journal of Herbology
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• v.35 no.1
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• pp.35-44
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• 2020

Objectives : The objective of this study was to investigate the therapeutic effect of Corni Fructus 30% ethanol extract (CFE) on the monosodium iodoacetate (MIA)-induced osteoarthritis rats. Methods : The subjects were divided into 4 groups ; Normal group (N, n=10), MIA-induced osteoarthritis control group (Con, n=10), indomethacin 5 mg/kg treated group (INDO, n=10), CFE 200 mg/kg treated group (CFE, n=10). Blood and articulation tissues were collected after two weeks of drug administration. Oxidative stress was analyzed with reactive oxygen species (ROS), peroxynitrite (ONOO-). And the Nuclear factor erythroid-2 (Nrf2), heme oxygenase-1 (HO-1), superoxide dismutase (SOD), catalase, glutathione peroxidase-1/2 (GPx-1/2), Nuclear Factor Kappa B p65 (NF-κBp65), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), tumor necrosis factor-alpha (TNFα), interleukin-6 (IL-6), Interleukin 1β (IL-1β), matrix metalloproteinase-1 (MMP-1), and tissue inhibitor of metalloproteinases-1 (TIMP-1) were investigated by western blot. Results : The administration of CFE showed a significant reduction of changes in relative hind paw weight distribution. Reactive oxygen species (ROS) and peroxy nitrite (ONOO-) levels of articulation tissues were significantly decreased in CFE compared to the control group. Western blot measurements of Nrf2, HO-1, SOD, catalase, GPx-1/2 showed that the CFE group was increased compared to the Con group. And western blot measurements of NF-κBp65, COX-2, iNOS, TNFα, IL-6, IL-1β showed that the CFE group was reduced compared to the Con group. Also CFE group decreased MMP-1 and increased TIMP-1. Conclusion : Based on the above results, it can be seen that osteoarthritis is improved when Corni Fructus 30% ethanol extract treated.

• The Korea Journal of Herbology
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• v.35 no.3
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• pp.17-24
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• 2020

Objectives : The objective of this study was to evaluate the gastric protective effect of Curcuma Longae Rhizoma (CLR) in 150 mM HCl/60% ethanol induced gastric ulcer (GU) in mice. Methods : Forty ICR mice were divided into five groups (n=8/Group): Nor group; Normal, Veh group; GU control, SC group; GU + sucralfate 10 mg/kg, CL; GU + CLR 30% ethanol extract 100 mg/kg, CH group; GU + CLR 30% ethanol extract 200 mg/kg. Then, mice were orally administered with 150 mM HCl/60% ethanol and caused GU. After 1 hr, mice were sacrificed, and blood and stomach tissue were collected. Results : CLR showed significance scavenging effects in 1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azinobis-3-ethyl-benzothiazoline-6-sulfonic acid (ABTS) radical scavenging activities (DPPH IC₅₀; 78.18 ± 0.60 ㎍/㎖, ABTS IC₅₀; 55.91 ± 1.86 ㎍/㎖). CLR significance reduce inflammatory-related factors such as cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β), and interleukin-6 (IL-6) via nuclear factor kappa B (NF-κB) inactivation. In addition, the activation of nuclear factor erythroid2-related factor 2 (Nrf2) significantly led to up-regulation of anti-oxidant enzymes including factors heme oxygenase-1 (HO-1), super oxide dismutase (SOD), and glutathione peroxidase-1/2 (GPx-1/2). Conclusions : Our discovery provides that CLR possesses anti-oxidant and anti-inflammatory effects. Hence, CLR may ameliorate the development of gastric ulcer though the inhibition of NF-κB inflammatory pathway and the elevation of Nrf2 anti-oxidant pathway.

• Journal of Internet of Things and Convergence
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• v.8 no.4
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• pp.25-40
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• 2022

This study aimed to understand the increasing number of elder abuses in South Korea, where entry into the super-aged society is imminent, by implementing text mining analysis. Korean Academic journals were obtained from 2004, the establishment year of the senior care agency, to 2021. We performed natural language processing of the titles, keywords, and abstracts and divided them into three segments of periods to identify latent meanings in the data. The results illustrated that the first section included 81 papers, the second 64, and the third 104 respectively, averaging 13.8 annually, which increased its numbers from 2014 until the decrease below the annual average in 2020. Word frequency demonstrated that the common keywords of the entire segments were 'elder abuse,' 'elders,' 'influences,' 'factors,' 'recognition,' 'family,' 'society,' 'prevention plans,' 'experiences,' 'abused elders,' 'abuse prevention,' 'depression,' etc., in consecutive order. TF-IDF indicated that 'influences,' 'recognition,' 'society,' 'prevention plans,' 'abuse prevention,' 'experiences,' 'depression,' etc., were the common keywords of all divisions. Network text analysis displayed that the commonly represented keywords were 'elder abuse,' 'elders,' 'influences,' 'factors,' 'characteristics,' 'recognition,' 'family,' 'prevention plans,' 'society,' 'abuse prevention,' and 'experiences' in the entire sections. concor analysis presented that the first segment consisted of 5 groups, the second 7, and the third 6. We suggest future directions for elder abuse research based on the results.

• Korean Chemical Engineering Research
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• v.60 no.3
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• pp.327-333
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• 2022

In this study, silicon/carbon nanotube/carbon (Si/CNT/C) composites for anode were prepared to improve the volume expansion of silicon used as a high-capacity anode material. Si/CNT were prepared by electrostatic attraction of the positively charged Si and negatively charged CNT and then hydrothermal synthesis was performed to obtain the spherical Si/CNT/C composites. Poly(vinylidene fluoride) (PVDF), polyacrylic acid (PAA), and styrene butadiene rubber (SBR) were used as binders for electrode preparation, and coin cell was assembled using 1.0 M LiPF₆ (EC:DMC:EMC = 1:1:1 vol%) electrolyte and fluoroethylene carbonate (FEC) additive. The physical properties of Si/CNT/C anode materials were analyzed using SEM, EDS, XRD and TGA, and the electrochemical performances of lithium-ion batteries were investigated by charge-discharge cycle, rate performance, dQ/dV and electrochemical impedance spectroscopy tests. Also, it was confirmed that both capacity and rate performance were significantly improved using the PAA/SBR binder and 10 wt% FEC-added electrolyte. It is found that Si/CNT/C have the reversible capacity of 914 mAh/g, the capacity retention ratio of 83% during 50 cycles and the rate performance of 70% in 2 C/0.1 C.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.34 no.4
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• pp.109-118
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• 2022

The data of the missing section among the vertex surface sea temperature observation data was imputed using the Bidirectional Recurrent Neural Network(BiRNN). Among artificial intelligence techniques, Recurrent Neural Networks (RNNs), which are commonly used for time series data, only estimate in the direction of time flow or in the reverse direction to the missing estimation position, so the estimation performance is poor in the long-term missing section. On the other hand, in this study, estimation performance can be improved even for long-term missing data by estimating in both directions before and after the missing section. Also, by using all available data around the observation point (sea surface temperature, temperature, wind field, atmospheric pressure, humidity), the imputation performance was further improved by estimating the imputation data from these correlations together. For performance verification, a statistical model, Multivariate Imputation by Chained Equations (MICE), a machine learning-based Random Forest model, and an RNN model using Long Short-Term Memory (LSTM) were compared. For imputation of long-term missing for 7 days, the average accuracy of the BiRNN/statistical models is 70.8%/61.2%, respectively, and the average error is 0.28 degrees/0.44 degrees, respectively, so the BiRNN model performs better than other models. By applying a temporal decay factor representing the missing pattern, it is judged that the BiRNN technique has better imputation performance than the existing method as the missing section becomes longer.

• Journal of Digital Convergence
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• v.20 no.2
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• pp.191-202
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• 2022

This study is about the effect of experience activities of fam tours in Korea on brand assets and revisit intention to revisit. In other words, the fam tour experience(feel, relate, sense, think, act) in research hypothesis 1 will have a positive (+) influence on brand assets(recognition, image, perceived quality, loyalty, and exclusive assets). In addition, it was set that the brand asset in Hypothesis 2 would have a positive (+) significant effect on the revisit intention. To verify this, 362 questionnaires were collected from MZ households in the metropolitan area and statistical analysis was conducted. The analysis results are as follows. First, in Hypothesis 1-1, the fam tour experience (feel, relate, act) has a positive (+) effect on awareness, In Hypothesis 1-2, the fam tour experience (relate, sense, think) has the effect of positive (+) on the image, In Hypothesis 1-3, the fam tour experience (feel, relate, sense, think, act) is the influence of perceived quality, In Hypothesis 1-4, the fam tour experience(sense, act) has a positive effect on loyalty, In Hypothesis 1-5, the fam tour experience (feel, relate, sense, think) had a positive (+) effect on exclusive assets. The brand assets(awareness, image, quality, loyalty, and exclusive assets) of the rural fam tour in Hypothesis 2 were significant for revisit intention.

• Journal of Digital Convergence
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• v.20 no.5
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• pp.547-557
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• 2022

The numbers of occurrences and the amount of spills of marine oil pollution have increased, and accordingly, it is necessary to secure additional control capabilities. Therefore, it was intended to present an empirical basis for improving the overall idle capacity through the relocation of control ships existing in each region. First, the marine pollution index was derived and the control capability compared to the marine pollution index of each region was compared to examine the appropriateness of the deployment of control ships. The marine oil pollution risk index was derived by multiplying the nine items that cause marine pollution by the weight derived by experts. We checked the control capacity (A) compared to the marine pollution risk index (F) for each sea area. Mokpo (F:13.4, A:1.9), Busan (F:14.3, A:6.4), and Yeosu (F:21.5, A:16.6) are the areas that lack control capabilities compared to the marine pollution risk index. On the other hand, the areas that have room for control compared to the marine pollution risk index for each sea area are Masan (F: 5.9, A:13.3), Gunsan (F:1.7, A:8.3), and Jeju (F:2.7, A:6.9). Therefore, for improving the standardized control capacity proportional to the risk of marine pollution nationwide, it is suggested that the control ships of Masan, Gunsan, and Jeju should be relocated to Mokpo, Busan, and Yeosu, which lack control capacity.