• Journal of the Korean Chemical Society
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• v.36 no.3
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• pp.419-427
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• 1992

The performance of homemade thermal field-flow fractionation (ThFFF) and the optimization for separation are investigated in terms of retention parameters and selectivity using polystyrene standards. The ribbonlike channel was constructed by sandwiching two Mylar spacers between two highly polished copper bars which serve as channel walls. The hot bar was heated by two electrical cartridge heaters and the cold bar had holes through the entire length, allowing tap water as coolant to enter. It has been observed that the retention of polystyrenes increases as the temperature gradient increases. And the retention decreases as the cold wall temperature increases from 20 to $45^{\circ}C$. In comparison with size exclusion chromatography, ThFFF is more selective but has relatively low efficiency. It has been found that the plate height is proportional to the flow velocity and good estimates of polydispersities can be made directly from the ThFFF data.

• Korean Journal of Radiology
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• v.19 no.6
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• pp.1130-1139
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• 2018

Objective: To compare the therapeutic efficacy between conventional transarterial chemoembolization (cTACE) and combined therapy using cTACE and radiofrequency ablation (RFA) in ultrasound (US)-invisible early stage hepatocellular carcinoma (HCC). Materials and Methods: From January 2008 to June 2016, 167 patients with US-invisible early stage HCCs were treated with cTACE alone (cTACE group; n = 85) or cTACE followed by immediate fluoroscopy-guided RFA targeting intratumoral iodized oil retention (combined group; n = 82). Procedure-related complications, local tumor progression (LTP), time to progression (TTP), and overall survival (OS) were compared between the two groups. Multivariate analyses were performed to identify prognostic factors. Results: There was no major complication in either group. The cTACE group showed higher 1-, 3-, and 5-year LTP rates than the combined group; i.e., 12.5%, 31.7%, and 37.0%, respectively, in the cTACE group; compared to 7.3%, 16.5%, and 16.5%, respectively, in the combined group; p = 0.013. The median TTP was 18 months in the cTACE group and 24 months in the combined group (p = 0.037). Cumulative 1-, 3-, and 5-year OS rates were 100%, 93.2%, and 87.7%, respectively, in the cTACE group and 100%, 96.6%, and 87.4%, respectively, in the combined group (p = 0.686). Tumor diameter > 20 mm and cTACE monotherapy were independent risk factors for LTP and TTP. Conclusion: Combined therapy using cTACE followed by fluoroscopy-guided RFA is a safe and effective treatment in US-invisible early stage HCCs. It provides less LTP and longer TTP than cTACE alone.

• Journal of Internet Computing and Services
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• v.24 no.4
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• pp.85-92
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• 2023

Deep learning applications are increasingly being leveraged for disease detection tasks in medical imaging modalities such as X-ray, Computed Tomography (CT), and Magnetic Resonance Imaging (MRI). Most data-centric deep learning challenges necessitate the use of supervised learning methodologies to attain high accuracy and to facilitate performance evaluation through comparison with the ground truth. Supervised learning mandates a substantial amount of image and label sets, however, procuring an adequate volume of medical imaging data for training is a formidable task. Various data augmentation strategies can mitigate the underfitting issue inherent in supervised learning-based models that are trained on limited medical image and label sets. This research investigates the enhancement of a deep learning-based rib fracture segmentation model and the efficacy of data augmentation techniques such as left-right flipping, rotation, and scaling. Augmented dataset with L/R flipping and rotations(30°, 60°) increased model performance, however, dataset with rotation(90°) and ⨯0.5 rescaling decreased model performance. This indicates the usage of appropriate data augmentation methods depending on datasets and tasks.

• Fashion & Textile Research Journal
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• v.25 no.3
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• pp.386-397
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• 2023

In this study, the efficacy of ultrasonic washing in cotton and wool fabrics was compared and evaluated against conventional washing in terms of cleaning properties and fabric deformation. Factors such as washing temperature, time, liquid ratio, and detergent concentration were kept varied, and the cleaning properties of sebum-soiled fabrics were assessed using different detergents such as alcohol ethoxylate, linear alkylbenzenesulfonate, and IEC 60456 Reference Detergent A^*. In addition, the effects and emulsification power of enzymes and oxygen bleach were examined. To compare the cleaning properties with general washing, a launder-O-meter was used. To investigate fabric deformation during the washing process, the loosening test cloth, shrinkage test cloth, and mechanical strength test cloth were compared between ultrasonic washing machines and household drum washing machines. The results indicate that ultrasonic washing exhibits superior cleaning properties than launder-O-meter when the temperature is low and the washing time is short. Furthermore, there is less deformation and damage during the washing process. It was also observed that the activity of the detergent increases when ultrasonic waves are applied to the washing process. Considering the increasing tendency to pursue convenience and simplicity in clothing management as well as the anticipated commercialization of smart clothing with built-in electric circuits, ultrasonic laundry could serve as a new alternative to existing laundry methods.

• Journal of The Korean Society of Integrative Medicine
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• v.12 no.3
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• pp.143-153
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• 2024

Purpose : Forward head posture (FHP), characterized by the anterior positioning of the head relative to the spine, is a common postural deviation that can lead to neck pain, reduced mobility, and muscle imbalances. Recently, high-frequency deep heat therapy (HFDT) has been gaining attention for the intervention of FHP. This research aims to investigate the efficacy of HFDT in comparison to instrument assisted soft-tissue mobilization (IASTM) for treating FHP among 30 young adults. Methods : Participants were randomly assigned to either the HFDT or IASTM group. The study focused on examining changes in neck joint mobility, pain thresholds, rounded shoulder distance, lower trapezius muscle strength, and neck dysfunction. Measurements were taken before and after the interventions. Paired t-tests were used for within-group analyses, and independent t-tests were employed for between-group comparisons. The statistical significance level α was set to .05. Results : Statistically significant improvements were observed across all measured parameters in both groups (p<.05). The HFDT group showed significantly greater enhancements in neck joint mobility, pain thresholds, rounded shoulder distance, lower trapezius muscle strength, and neck dysfunction parameters. Specifically, HFDT was more effective than IASTM in improving neck joint mobility, right upper trapezius pain threshold, left rounded shoulder distance, and right lower trapezius strength. The only exceptions were neck flexion range of motion, left upper trapezius pain threshold, right rounded shoulder distance, and left lower trapezius strength, where no significant differences were found between the groups. Conclusion : The findings suggest that HFDT, by combining the benefits of high-frequency therapy and manual therapy, effectively alleviates upper trapezius muscle pain and tension, enhances neck mobility, and strengthens lower trapezius muscles. Thus, HFDT could be considered a valuable intervention for clinicians aiming to address FHP and associated musculoskeletal problems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.11
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• pp.1635-1644
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• 1993

In this paper, we examine the statistical characteristics of edge enhancing filters and their efficacy as preprocessing operator before edge detection. In particular, edge enhancing filters called the Comparison and Selection(CS), Hachimura-kuwahara(HK), and Selective Average(SA) filters are considered. These filters can reduce noise while producing step-type edges, thus seem to be effective for preprocessing noisy images prior to applying edge detecors. The ability of edge enhancing filters to suppress white Gaussian noise and the error probabilities occured during the edge detection following SA prefiltering are evaluated statistically through numerical analysis. The effect of prefiltering on edge detection is assessed by applying the edge enhancing fitters to a noise image degraded by additive white noise prior to applying the Sobel operator and the Laplacian of Gaussian( LoG ) operator, respectively. It is shown that the edge enhancing filters tend to produce ideal step-type edges while reducing the noise reasonably well, and the use of edge enhancing filters prior to edge detection can improve the performance of subsequent edge detector.

• Communications of Mathematical Education
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• v.27 no.2
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• pp.135-163
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• 2013

This study dealt with the measurements of the positive psychological experience of high school students in relation to mathematics learning by using PPE-M. The purpose of this study is to compare the positive psychology of the high school students based on the grade and gender variables. Measured data for the purpose of this study examined the difference between the gifted students and the general students through a t-test. In addition, differences were analyzed by grade and gender variables. And One-way ANOVA was conducted to see the difference according to the course variables. The difference between the two groups was meaningful in PPE-M total score. There was meaningful difference in all of 5 areas and 19 factors except for 4 factors (Insight, Honesty, Full with pride, and Achievement). However, there was no difference according to grade levels. The comparison between the gender in the ordinary students shows meaningful difference in 11 factors, not in 12 (Judgment, Insight, Honesty, Prudence, Modesty & Kindness, Gratitude & Happiness, Flow, Superiority feeling, Achievement, High pleasure, Full with pride, and Self-efficacy). Affiliation makes meaningful difference in 22 factors except for Honesty.

• Journal of Families and Better Life
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• v.25 no.4
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• pp.31-41
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• 2007

This study aimed to develop a cognitive-behavioral group counseling program for depression and aggressiveness in adolescents with delinquent propensity and to examine its efficacy through pre- and post-tests. The program included cognitive restructuring, exposure training, social skills training and relaxation training. Juvenile Delinquency Scale, BDI, K-YSR, and BDHI were administered to 520 3rd grade middle-school female students to assess their levels of delinquency, depression and aggressiveness. Initially 41 students who met all the following criteria were selected: 1) top 15% scores on Juvenile Delinquency Scale, 2) top 30% scores on BDI, K-YSR and BDHI respectively. Individuals currently receiving clinical treatment were excluded. Finally 39 students were selected and randomly assigned to either a treatment group(n=20) or a control group(n=19). Then the students in the treatment group were divided into 4 subgroups. The program consisted of 12 weekly sessions, approximately $1.5{\sim}2$ hours in duration. Pre- and post-tests administered to both groups included Juvenile Delinquency Scale, BDI, K-YSR, BDHI, and CLAB. Additionally, MESSY for teachers was added at pre- and post-tests. The collected data were statistically analyzed through independent t-test and paired t-test. The results of the study were as follows: 1) The students in the treatment group showed a significant reduction in the level of depression and aggressiveness in comparison with those in the control group. 2) Teachers reported a significant reduction in internalizing/externalizing behaviors of the students in the treatment group.

• Journal of the Korea Safety Management & Science
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• v.12 no.4
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• pp.41-51
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• 2010

This paper describes the development of various lighting equipment adapting Ultra Constant Discharge Lamp that has newly been on commercial supply in the market. Meeting the required conditions of lighting equipment, various types of UCD Lamp equipment with excellent performances could be successfully developed. In order to provide a guideline for the economical lighting product selection, the analyzed data comparison between Hi-pressure Sodium Lamp which has been the most popular lamp for street lighting and UCD Lamp is provided. The conclusions of the study are made as follows; (1) The performance measurement result of UCD Lamp shows excellent Luminous Efficacy as 108Lm/W, daylight-like Color Rendering Index as 90Ra, and the best operating temperature range as $-50^{\circ}C{\sim}+85^{\circ}C$. Comparing to the Hi-pressure Sodium Lamp, UCD could be evaluated as much superior products. (2) In an assembled status with the lighting fixture (Type STB형-60W), UCD Lamp was tested OK for one hour duration at the temperature range form $-50^{\circ}C$ to $+85^{\circ}C$ and the humidity of 98%. The operation at the extremely low temperature can be an excellent feature to enable the export to the cold temperature regions such as Northern Europe and Russia and the specific applications for defense systems and special industry. (3) As UCD Lamp is a genuine Korea made product following Energy-saving and Eco-friendly policy, it should be appreciated as one of the best $CO^2$ reduction Green product.

• Korean Journal of Occupational Health Nursing
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• v.30 no.3
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• pp.120-131
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• 2021

Purpose: This study aimed to compare the effects of an 8 week, self-managed, app-based and poster-based stretching program on musculoskeletal symptoms, flexibility, stretching frequency, self-efficacy, social support, and musculoskeletal disorder knowledge in small manufacturing business workers. Methods: This was a cluster randomized, two-group pretest-posttest design. Workers were assigned to either an app-based (n=20) or a poster-based (n=25) stretching intervention. Both groups received an educational class. The app group also received mobile phone text messages and an app with stretching videos, stretching alarms, stretching records, and information on musculoskeletal disorders. The poster group received workplace stretching posters. Data were collected from April to September 2018 and analyzed with the 𝑥² test, paired t-test, and independent t-test. Results: There was only a significant difference in social support. Significant increase in flexibility and musculoskeletal symptoms were noted for both groups, but social support and musculoskeletal disorder knowledge were significantly changed only in the poster group. More than half of the workers practiced stretching at least 3 times a week. Conclusion: The 8 week, self-managed, workplace stretching program was effective to increase flexibility and stretching frequency to at least 3 times a week. However, effective interventions for musculoskeletal symptoms could not be identified.