• Journal of Mushroom
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• v.17 no.3
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• pp.136-143
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• 2019

In this study, we analyze the antioxidant and anti-inflammatory activities of various extracts of Cryptoporus volvatus. Three extracts were prepared using hot-water, 70% ethanol, and 70% methanol. Compared to the hot-water and 70% methanol extracts, the 70% C. volvatus ethanol extracts showed significantly higher DPPH radical scavenging activities (76.1%), nitrite scavenging activities (29.5%), and total polyphenol content (9.17 mg GAE/g). The DPPH radical and nitrite scavenging activities of C. volvatus both correlated significantly with the total polyphenol content. The Pearson's correlation coefficient of DPPH radical and nitrite scavenging activities with total polyphenol content were r = 0.744 (p<0.05) and r = 0.921 (p<0.01), respectively. To test their anti-inflammatory effects, nitric oxide production and cell viability were measured by performing nitric oxide (NO) and MTT assays on lipopolysaccharide-treated RAW 264.7 cells. The NO production levels of the 70% ethanol extract-treated cells were slightly lower than those of the others. In our MTT assay, the hot-water extracts showed higher cell viabilities (81.4%) than those of 70% ethanol and 70% methanol extracts. The ${\beta}$-glucan content of C. volvatus was 37.8%. From the results of this study, it is suggested that C. volvatus, an easily accessible wild mushroom, has potential to be used in the development of medicines, cosmetics, and functional health foods.

• The Korean Journal of Applied Statistics
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• v.34 no.3
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• pp.375-388
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• 2021

This paper aims to help prevent the spread of COVID-19 by analyzing confirmed cases of COVID-19 in Daejeon. A high volume of visitors, downtown areas, and psychological fatigue with prolonged social distancing were considered as risk factors associated with the spread of COVID-19. We considered the weekly confirmed cases in each administrative district as a response variable. Explanatory variables were the number of passengers getting off at a bus station in each administrative district and the elapsed time since the Korean government had imposed distancing in daily life. We employed a mixed-effects zero-inflated Poisson regression model because the number of cases was repeatedly measured with excess zero-count data. We conducted k-means clustering to identify three groups of administrative districts having different characteristics in terms of the number of bars, the population size, and the distance to the closest college. Considering that the number of confirmed cases might vary depending on districts' characteristics, the clustering information was incorporated as a categorical explanatory variable. We found that Covid-19 was more prevalent as population size increased and a district is downtown. As the number of passengers getting off at a downtown district increased, the confirmed cases significantly increased.

• Journal of Korea Port Economic Association
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• v.38 no.1
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• pp.49-71
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• 2022

The purpose of this paper is to study the effect of the corporate social responsibility by port operation organization on the brand asset, reputation and relationship performance perceived by interested parties. To achieve such a purpose, literature survey on various research papers and thesis, research report is carried out and also reliability analysis, validity test and multiple regression analysis using SPSS 18.0 are used. To verify a established research model for empirical analysis and hypotheses, questionnaires are distributed to the port operation organization, terminal operators, shipping companies and NGO. Total 414 copies of questionnaires were collected and used in this analysis. The main results of the study are summarized as below. First, it was confirmed that social responsibility of the port operation organization are classified into three categories; economic, legal, and charitable and ethical responsibility. Second, economic responsibility has a positive impact on the brand awareness and reputation. Third, legal responsibility has a positive impact on the trust and commitment. Fourth, charitable and ethical responsibility has a positive impact on brand image and awareness, reputation, trust and commitment. Further additional empirical research can be extended by distributing more questionnaires including several port operation organizations in Busan and Incheon.

• 한국노년학
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• v.40 no.3
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• pp.429-442
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• 2020

The purpose of this research was to examine changes in the physical fitness, activities of daily living performance, and cognitive status of the frail elderly by combined exercise programs. The combined exercise program consisted of an aerobic exercise for the elderly and a four-color ladder exercise for improving of cognitive ability and physical fitness. Twenty-one frail elderly participated in this study, they were divided into 12 exercise groups and nine control groups. The exercise group conducted the combined exercise program of 60 minutes, twice a week, for10 weeks, while the control group maintained their normal lives. Strength, flexibility, agility, coordination, ADL and MMSE-K were measured. Exercise group showed significant improvement in grip strength compared to control group. In addition, ADL showed significant improvement only in the exercise group. The results of this study showed that participation in the combined exercise program of the el derl y was effective in improving the grip strength, and in preventing various physical functions and cognitive conditions decline.

• Journal of Korea Water Resources Association
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• v.55 no.11
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• pp.913-922
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• 2022

The purpose of this research is to propose the measurement of improving DEM by using the water surface range of SAR image analysis for river corridors and to suggest the construction of satellite-based 3D river spatial information of inaccessible regions such as North Korea. For this research, it has been progressed from the accessible area, watershed of Namgang river, the branch of Nakdonggang river. The satellite image was collected from SAR satellite image data for a year in 2021 which was provided by ESA from Sentinel-1A/B data and extracted from the seasonal water surface area. Ground gauge water level was collected from hourly intervals data by WAMIS. The DEM was improved by analysis of the river altitude of water surface area change by the combination of the ground water level of minimum to maximum water surface area data extracted from SAR image analysis. After the improvement of DEM, the altitude of the river varied that it is defined to comprise more natural form of river DEM than the existing DEM. The correction validation of improvement DEM was necessary in field survey elevation data; however, the correction validation was not progressed due to the absence of the data. Although, the purpose of this research is to provide the improvement of DEM by using the analyzed water surface by existing DEM data and SAR image analysis. After the progression of additional correction validation research, we would plan to examine the application in other places and to progress the additional methodological research to apply in inaccessible and unmeasured area including the North Korea.

• Journal of the Korean Society of Radiology
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• v.16 no.1
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• pp.25-34
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• 2022

Brain computed tomography (CT) is useful for brain lesion diagnosis, such as brain hemorrhage, due to non-invasive methodology, 3-dimensional image provision, low radiation dose. However, there has been numerous misdiagnosis owing to a lack of radiologist and heavy workload. Recently, object detection technologies based on artificial intelligence have been developed in order to overcome the limitations of traditional diagnosis. In this study, the applicability of a deep learning-based YOLOv5s model was evaluated for brain hemorrhage detection using brain CT images. Also, the effect of hyperparameters in the trained YOLOv5s model was analyzed. The YOLOv5s model consisted of backbone, neck and output modules. The trained model was able to detect a region of brain hemorrhage and provide the information of the region. The YOLOv5s model was trained with various activation functions, optimizer functions, loss functions and epochs, and the performance of the trained model was evaluated in terms of brain hemorrhage detection accuracy and training time. The results showed that the trained YOLOv5s model is able to provide a bounding box for a region of brain hemorrhage and the accuracy of the corresponding box. The performance of the YOLOv5s model was improved by using the mish activation function, the stochastic gradient descent (SGD) optimizer function and the completed intersection over union (CIoU) loss function. Also, the accuracy and training time of the YOLOv5s model increased with the number of epochs. Therefore, the YOLOv5s model is suitable for brain hemorrhage detection using brain CT images, and the performance of the model can be maximized by using appropriate hyperparameters.

• Journal of the Korean GEO-environmental Society
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• v.24 no.2
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• pp.31-40
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• 2023

We installed temporary strong motion seismometers at the ground surface, 1 m, 2 m, and 9 m at an existing seismic station that houses permanent seismometers installed at 20 m and 100 m, to investigate the influence of installation depth on the recorded ambient and anthropogenic noise level and the characteristics of earthquake signals. Analysis of the ambient noise shows that anthropogenic noise dominates where vibration period T < 1 s at the studied site, whereas wind speed appears to be strongly correlated with the noise level at T > 1 s. Frequency-wavenumber analysis of 2D seismometer array suggests that ambient noise in short periods are predominantly body waves, rather than surface waves. The level of ambient noise was low at 9 m and 20 m, but strong amplification of noise level at T < 0.1 s was observed at the shallow seismometers. Both the active-source test result and the recorded earthquake data demonstrated that the signal level is decreased with the increase of depth. Our result also shows that recorded motions at the ground and 1 m are strongly amplified at 20 Hz (T = 0.05 s), likely due to the resonance of the 3 m thick soil layer. This study demonstrates that analysis of ambient and active-source vibration may help find optimal installation depth of strong motion seismometers. We expect that further research considering various noise environments and geological conditions will be helpful in establishing a guideline for optimal installation of strong motion seismometers.

• Membrane Journal
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• v.33 no.4
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• pp.181-190
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• 2023

Wastewater purification is one of the most important techniques for controlling environmental pollution and fulfilling the demand for freshwater supply. Various technologies, such as different types of distillations and reverse osmosis processes, need higher energy input. Capacitive deionization (CDI) is an alternative method in which power consumption is deficient and works on the supercapacitor principle. Research is going on to improve the electrode materials to improve the efficiency of the process. A reverse electrodialysis (RED) is the most commonly used desalination technology and osmotic power generator. Among many studies conducted to enhance the efficiency of RED, MXene, as an ion exchange membrane (IEM) and 2D nanofluidic channels in IEM, is rising as a promising way to improve the physical and electrochemical properties of RED. It is used alone and other polymeric materials are mixed with MXene to enhance the performance of the membrane further. The maximum desalination performances of MXene with preconditioning, Ti₃C₂T_x, Nafion, and hetero-structures were respectively measured, proving the potential of MXene for a promising material in the desalination industry. In terms of osmotic power generating via RED, adopting MXene as asymmetric nanofluidic ion channels in IEM significantly improved the maximum osmotic output power density, most of them surpassing the commercialization benchmark, 5 Wm^-2. By connecting the number of unit cells, the output voltage reaches the point where it can directly power the electronic devices without any intermediate aid. The studies around MXene have significantly increased in recent years, yet there is more to be revealed about the application of MXene in the membrane and osmotic power-generating industry. This review discusses the electrodialysis process based on MXene composite membrane.

• Journal of Intelligence and Information Systems
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• v.29 no.3
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• pp.229-247
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• 2023

With the increasing emphasis on anomaly detection across various fields, diverse anomaly detection algorithms have been developed for various data types and anomaly patterns. However, the performance of anomaly detection algorithms is generally evaluated on publicly available datasets, and the specific performance of each algorithm on anomalies of particular types remains unexplored. Consequently, selecting an appropriate anomaly detection algorithm for specific analytical contexts poses challenges. Therefore, in this paper, we aim to investigate the types of anomalies and various attributes of data. Subsequently, we intend to propose approaches that can assist in the selection of appropriate anomaly detection algorithms based on this understanding. Specifically, this study compares the performance of anomaly detection algorithms for four types of anomalies: local, global, contextual, and clustered anomalies. Through further analysis, the impact of label availability, data quantity, and dimensionality on algorithm performance is examined. Experimental results demonstrate that the most effective algorithm varies depending on the type of anomaly, and certain algorithms exhibit stable performance even in the absence of anomaly-specific information. Furthermore, in some types of anomalies, the performance of unsupervised anomaly detection algorithms was observed to be lower than that of supervised and semi-supervised learning algorithms. Lastly, we found that the performance of most algorithms is more strongly influenced by the type of anomalies when the data quantity is relatively scarce or abundant. Additionally, in cases of higher dimensionality, it was noted that excellent performance was exhibited in detecting local and global anomalies, while lower performance was observed for clustered anomaly types.

• Journal of Music and Human Behavior
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• v.19 no.2
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• pp.81-103
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• 2022

The effects of therapeutic instrumental music performance (TIMP) using a ukulele were examined in adults with central nervous system damage and impaired hand functions. The participants were three adults with neurological damage who participated in 30-min sessions twice a week over 6 weeks. Changes in hand function was measured by the Box and Block Test (BBT), the 9-Hole Peg Test (9-HPT), and the Jebsen-Taylor Hand Function Test (JTHFT). Following the intervention, all three participants showed increases in the BBT and 9-HPT scores, indicating positive changes in fine motor coordination and dexterity. In terms of the JTHFT, all three participants showed increases in the "writing" and "card flipping" subtask scores, indicating that the intervention was effective in improving more coordinated finger movements. All participants reported the satisfaction with the intervention. They also pointed out that they were motivated to play the ukulele and that following the intervention used their affected hand more frequently in daily activities. These findings suggest that TIMP with a ukulele for patients with central nervous system damage can have positive effects on their functional hand movements and motivate these patients to practice their rehabilitation exercises.