• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.2
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• pp.43-50
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• 2022

Even though the structural safety is confirmed in the design stage, the structural safety is not guaranteed in the construction stage because the structural system is not completed. In addition, since the construction period is shorter than the period of use of the building after completion, it is excessive to apply the same seismic load to the construction stage as in the design stage. ASCE 37-14 presents the concept of seismic load reduction factor during construction, but does not provide a clear application method. Therefore, in this study, the seismic load reduced according to the return period was applied to the example model of a residential middle-rise RC building. The construction stage of the example model was divided into five-story units, and seismic load with the change of the return period was applied to the construction stage models to analyze the change of seismic load during construction and to check the sectional performances of structural members. By comparing the design strength ratio of the shear wall at the design stage and the construction stage, the range of seismic load magnitudes that can assure the safety during construction of a residential middle-rise RC building was analyzed in terms of the return period.

• The Journal of the Korea Contents Association
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• v.22 no.6
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• pp.580-595
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• 2022

This study looked at the relationship between lifestyle choices and various substance addictions in young adults by applying the Relapse Prevention model of addiction. The data was obtained from a cross-sectional questionnaire (Depression and Anxiety Assessment Test) of 926 young adults aged 18~24 from 24 countries. Of these, 17.6% reported that they had a serious substance addiction, with alcohol addiction being the highest (11.2%), followed by nicotine (10.3%) and illicit drug (8.7%) usage. Results of chi-square test and logistic regression analysis revealed a significant association between various lifestyle factors (exercise patterns, intake of dietary nutrients like tryptophan, folic acid, omega-3 fatty acids and micronutrients, spiritual habits such as Bible reading and prayer) and addiction to various substances (illicit drugs, alcohol and nicotine). Depression was also found to be a significant factor influencing substance addiction. Interestingly, the risk of alcohol abuse was the highest at 9.870 (95% CI: 4.525-21.525) times among those who didn't have the habit of daily Bible reading. The highest risk of nicotine and illicit drug addiction was among those who consumed 'less than 1 serving' of dietary micronutrients per day compared to those who consumed '5 or more servings', with odds ratios of 9.606(95% CI: 2.726-30.111) and 8.642(95% CI: 2.022-37.378), respectively. These findings suggest that holistic lifestyle interventions may help prevent and reduce substance addiction in young adults.

• Composites Research
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• v.35 no.3
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• pp.134-138
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• 2022

In this study, Ti powder/Polymer concrete composites were processed by adding the PZT powder, one of the piezoelectric materials, to improve the vibration damping effect of Polymer concrete. Ti powder was added at a constant ratio in order to maximize the vibration damping effect using the piezoelectric effect. Three types of composite material specimens were prepared: a specimen without PZT powder, specimens with 2.5 wt% and 5 wt% of PZT powder. The vibration characteristics and compression properties were analyzed for all specimens. As a result, it was confirmed that as the addition ratio of PZT powder increased, the Inertance value at the resonant frequency decreased due to the piezoelectric effect when the vibration generated from Ti powder/polymer concrete was transmitted. Especially, the Inertance value was decreased by about 19.3% compared to the specimen without PZT at the resonant frequency. The change in acceleration with time also significantly decreased as PZT powder was added, confirming the effect of PZT addition. In addition, through the compression strength test, it was found that the degree of deterioration in compression properties due to the addition of PZT up to 5 wt% was insignificant, and it was confirmed that the powder was evenly dispersed in the composites through the cross-sectional analysis of the specimen.

• The Journal of the Korea Contents Association
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• v.22 no.1
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• pp.601-610
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• 2022

Although the number of people insured by private health insurance in Korea is steadily increasing, the household burden or the status of multiple purchasing for private health insurance has not been addressed. In this study, data of the 2011-2018 Korea Health Panel Survey was used to examine the purchasing trend of Korean households' private health insurance. Households with more than three private health insurance per household member were defined as the 'poly-purchases'. The logit model was applied to analyze factors associated with poly-purchase of private health insurance using 2018 cross-sectional data. From 2011 to 2018, the number of insurances purchased by Korean households increased (4.0 to 4.6), the number of insurances per capita increased (1.3 to 1.6), and the proportion of the poly-purchasing households increased (5.2% to 10.8%). As a result of logit analysis, the probability of poly-purchasing was increased when the household head was a woman, with a high level of education and income, and when the job of the household head was a service or sales. Poly-purchasing was less likely when the family was subsidized with Medical Aids and suffered with more chronic diseases. The results of this study serve basic evidence for establishing policies regarding private health insurance, such as establishing the relationship between public and private insurance.

• Tuberculosis and Respiratory Diseases
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• v.84 no.2
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• pp.105-114
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• 2021

Background: Complementary and alternative medicine (CAM) has been used frequently, and its use continues to increase in lung cancer patients, despite insufficient scientific of its efficacy. To investigate this situation, we analyzed the current awareness and use of CAM in Korean lung-cancer patients. Methods: This prospective survey-based study was performed at seven medical centers in South Korea between August and October 2019. The survey assessed general patient characteristics and the awareness and use of CAM. We analyzed differences in the clinical parameters of patients aware and not aware of CAM and of CAM non-users and users. Results: Of the 434 patients included in this study, 68.8% responded that they were aware of CAM and 30.9% said they had experienced it. In univariate analysis, the patients aware of CAM were younger with poor performance status, had advanced-stage lung cancer, received more systemic therapy, and received concurrent chemoradiation therapy (CCRT). By multiple logistic regression, younger age, poor performance status, advanced stage, and prior CCRT were identified as independent risk factors for CAM awareness. There were no significant differences in the general characteristics and cancer-associated clinical parameters of CAM non-users and users. Conclusion: Specific clinical parameters were associated with patients' awareness of CAM, although there were no significantly different characteristics between CAM users and non-users.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.7
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• pp.1106-1115
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• 2021

In this study, a fin that controls ship stern flow was attached on stern hull of a 80k bulk carrier to improve resistance performance. The rectangular cross-sectional fin was attached at several locations on the hull, and angle to streamline was changed with constant length, breadth, and thickness. The resistance performance and wake on propeller plane of the hull with and without the fin were analyzed using model-scale computational fluid dynamics simulation. The analysis results were extrapolated to full-scale to compare the performance and wake of the full-scale ship. First, the fin changed path of bilge vortex that flowed into the propeller along the stern hull without the fin to transom stern. This change increased pressure of the stern hull and upper region of the propeller, so pressure resistance and total resistance of the hull were reduced - the nearer the fin location to after perpendicular (AP) and base line of the hull, the larger the reduction of the resistances. Second, nominal wake fraction of the hull with the fin was lower than that without the fin. This dif erence was in proportion to the angle of the fin, but the total resistance reduction was in proportion until a certain angle at which the reduction was maximum. The largest total resistance reduction was approximately 2.1% at 12.5% of length between perpendiculars from the AP, 10% of draft from the base line, and 14° with respect to the streamline.

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.3
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• pp.253-263
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• 2022

A buccal pit is a prominent point-like depression that appears at the cervical end of the mandibular molar developmental grooves. A defective buccal pit can be defined as a buccal pit in which the continuity of the dentinoenamel junction is broken and the pit extends to the dentinal level. This study aimed to determine the frequency of buccal pits and defective buccal pits in un-erupted mandibular first and second molars using cone-beam computed tomography (CBCT). The analysis was performed on CBCT images taken from 417 Korean children and adolescents who visited the Department of Pediatric Dentistry, Yonsei University Dental Hospital between 2004 and 2020. Based on cross-sectional views of CBCT images, buccal pits were categorized into 4 classes according to the depth of the pits. The expression rate of the buccal pits was 29.1%. The prevalence of defective buccal pits was 7.9%. The buccal pits tended to develop bilaterally. To date, this is the most comprehensive study on the frequency of buccal pits with the largest sample size. This was the first attempt worldwide to analyze the depth of the buccal pit using CBCT images and to define a defective buccal pit worldwide.

• The Journal of Engineering Geology
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• v.32 no.4
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• pp.671-684
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• 2022

This study verified the stability of a high-strength combined buried pile retaining wall and its applicability in the field. A cast-in-place (C.I.P) retaining wall and the high-strength combined embedded pile retaining wall were compared and analyzed numerically. The numerical analysis assessed the ground behavior and stability (and thus field applicability) of a high-strength combined buried pile retaining wall using data measured in the field. The experimental results showed that the cross-sectional force and displacement of the high-strength bonded pile retaining wall were reduced by 13.6~19.7%, the shear force increased by 0.7~4.7%, and the bending moment increased by 4.5~8.8% relative to the values for the C.I.P retaining wall. Examination of the amount of subsidence in the ground around the excavation showed that the maximum settlement of the C.I.P retaining wall was 46.89 mm and that at the high-strength combined buried pile retaining wall was 39.37 mm. Overall, designing a high-strength combined embedded pile retaining wall by applying the maximum bending moment and shear force calculated using the elastic beam method to the site ground was shown to achieve the safety of all members, as member forces were generated within the elastic region.

• Journal of Korean Physical Therapy Science
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• v.29 no.3
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• pp.12-20
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• 2022

Background: The purpose of this study was to investigate the changes of trunk and lower extremity muscle activity according to the compensation of arm during bridge movement of healthy subject. Design: Cross-sectional Study. Methods: Twenty healthy subjects participated in this study. The subjects performed bridge exercise with 3 different arm positions(arm abduction 45°, 90° and cross-arms) and measured the muscle activity of the trunk and lower extrimity. During bridge exercise with 3 different arm positions, trunk (rectus abdominis, erector spinae) and lower extrimity muscle activity (gluteus medius, biceps femoris, tibialis anterior) were measured using wireless surface EMG. Results: Rectus abdominis and gluteus medius muscle were most activated during bridge exercise with arm abduction 90° and erector spinae and biceps femoris muscle were most activated during bridge exercise with arm abduction 45°. In addition, tibialis anterior muscle was most activated during bridge exercise with arm cross. However, these difference in muscle activity according to the arm position was not statistically significant. Conclusion: As a result of this study, we think that the change in arm position does not induce sufficient instability to increase the muscle activity of the trunk and lower extremity muscles. Therefore, various approaches for inducing instability of the support surface for increasing muscle activity when applying bridge movement in clinical practice should be explored.

• Journal of Dental Anesthesia and Pain Medicine
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• v.23 no.1
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• pp.29-37
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• 2023

Background: A high incidence (40-73%) of postoperative nausea and vomiting (PONV) has been reported following orthognathic surgery, and various risk factors have been associated with it. Identifying PONV risk factors based on initial onset time will help establish preventive measures. This study aimed to identify factors that are significantly related to PONV based on the initial onset time after orthognathic surgery. Methods: This study included 590 patients who underwent orthognathic surgery. Multivariate logistic regression analysis was performed to identify the risk factors that are significantly related to PONV. The objective variables were classified into three categories: no PONV, early PONV (initial onset time: 0-2 h after anesthesia), and late PONV (initial onset time: 2-24 h after anesthesia). The explanatory variables included relevant risk factors for PONV, as considered in previous studies. Results: Total intravenous anesthesia with propofol was a significant depressant factor for early PONV (adjusted odds ratio [aOR] = 0.340, 95% confidence interval [CI] = 0.209-0.555) and late PONV (aOR = 0.535, 95% CI = 0.352-0.814). The administration of a combination of intraoperative antiemetics (vs. no administration) significantly reduced the risk of early PONV (aOR = 0.464, 95% CI = 0.230-0.961). Female sex and young age were significant risk factors for late PONV (aOR = 1.492, 95% CI = 1.170-1.925 and unit aOR = 1.033, 95% CI = 1.010-1.057, respectively). Conclusion: We identified factors that are significantly related to PONV based on the initial onset time after orthognathic surgery. Total intravenous anesthesia with propofol significantly reduced the risk of PONV not only in the early period (0-2 h after anesthesia) but also in the late period (2-24 h after anesthesia).