• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.2
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• pp.138-144
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• 2023

In this study, the effect of electrochemical treatment in mitigating alkali leaching into an aquatic environment was investigated. To modify the surface of cement paste, 1000 mA/m² of the direct current was passed through anodic graphite to the external mesh for 4 weeks. Then, the cement paste specimen was exposed to still water in air-tight condition to prevent natural healing of alkali leaching in the water. For 100 days of monitoring in water, the pH value was marginally increased at the electrochemical treatment, while control specimen ranked to the even higher pH accounting for 13.2 in the pH. Moreover, after the pH monitoring, the pH profile for the paste specimen indicated that the electrochemical treatment was effective in securing the higher alkalinity of cement matrix. The water obtained from alkali leaching process, was used to ecological test for Daphnia magna. It was evident that the electrochemical treatment had minimal adverse effect on ecological impact, while control specimen mostly immobilized the standard Daphnia magna.

• 한국체육학회지인문사회과학편
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• v.55 no.6
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• pp.661-676
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• 2016

The purpose of this study is to draw a systematic access method of career intervention for dance majors. This study conducted Delphi survey and Analytic Hierarchy Process(AHP). As a result of study, 16 elements of career intervention were produced in total 4 areas. Results show that vocational guidance puts emphasis on the understanding of the various vocations, career education on the career planning and goal, career counseling on the macro-narrative to the life and career intervention network on the dance job fair and workshop. In the complex weight of all factors, ratings of weight show that dance vocation guidance and career education are demanded significantly. Results show that expansion of career alternatives, application of diversified dance career development road map to the curriculum, development of test tool and outcome standard, dance educators' systematic career intervention education and systematization of network for career support were suggested as measures for dance career intervention. This study discussed about dynamic reality and systematic access method for dance majors based on theories of Holland(1997), Super(1990), and Savickas(2005).

• Journal of the Korean Society of Radiology
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• v.17 no.3
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• pp.465-472
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• 2023

In predicting vascular disease, this study attempted to identify changes in the carotid intima-media thickness in patients who underwent carotid artery ultrasonography and hematological tests and to find out the effect of risk factors on the expression of atherosclerotic plaque. A retrospective analysis was conducted on 469 healthy adults who visited the hospital for the purpose of medical examination and performed carotid artery ultrasonography. As a result, carotid intima-media thickness, age, body mass index, waist circumference, systolic blood pressure, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and glucose were analyzed as significant predictors of atherosclerotic plaque (p<0.001). The risk ratio was calculated based on the cut off value of the risk factors of the atherosclerotic plaque determined through ROC curve analysis, followed by 8.06 times the carotid intima-media thickness, 7.53 times the age, 3.97 times the waist circumference and 2.02 times the glucose. Therefore, in this study it was possible to prepare a Korean standard for clinical risk factors that affect the presence of absence of atherosclerotic plaque and observation of carotid artery ultrasonography is thought to help diagnose or predict cardiovascular disease early.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5A
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• pp.511-518
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• 2009

This study was intended to compare and evaluate the adhesion of High flowing Self-compacting Concrete (HSCC), Conventional Concrete (CC) and deformed bar based on concrete strength 3 (30, 50 and 70 MPa), among the factors affecting the bond strength between concrete and rebar, after fabricating the specimen by modifying the rebar position at Horizontal reinforcement at bottom position (HB), horizontal reinforcement at top position (HT) and vertical reinforcement type (V). As a result of measuring bond strength of HB/HT rebar to evaluate the factor of the rebar at top position, the bond strength of HB/HT rebar at 50 and 70 MPa was 1.3 or less and at 30 MPa, HSCC and CC appeared to be 1.2 and 2,1, respectively. Thus, when designing the anchorage length according to the concrete structure design standard (2007) at HSCC 30, 50 and 70 MPa, it would be desirable to reduce the correction factor of anchorage length of the horizontal reinforcement at top position, which is suggested for the reinforcement at top position, to less than 1.3 of CC.

• Tuberculosis and Respiratory Diseases
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• v.86 no.3
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• pp.203-215
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• 2023

Background: Surgical resection is the standard treatment for early-stage lung cancer. Since postoperative lung function is related to mortality, predicted postoperative lung function is used to determine the treatment modality. The aim of this study was to evaluate the predictive performance of linear regression and machine learning models. Methods: We extracted data from the Clinical Data Warehouse and developed three sets: set I, the linear regression model; set II, machine learning models omitting the missing data: and set III, machine learning models imputing the missing data. Six machine learning models, the least absolute shrinkage and selection operator (LASSO), Ridge regression, ElasticNet, Random Forest, eXtreme gradient boosting (XGBoost), and the light gradient boosting machine (LightGBM) were implemented. The forced expiratory volume in 1 second measured 6 months after surgery was defined as the outcome. Five-fold cross-validation was performed for hyperparameter tuning of the machine learning models. The dataset was split into training and test datasets at a 70:30 ratio. Implementation was done after dataset splitting in set III. Predictive performance was evaluated by R² and mean squared error (MSE) in the three sets. Results: A total of 1,487 patients were included in sets I and III and 896 patients were included in set II. In set I, the R² value was 0.27 and in set II, LightGBM was the best model with the highest R² value of 0.5 and the lowest MSE of 154.95. In set III, LightGBM was the best model with the highest R² value of 0.56 and the lowest MSE of 174.07. Conclusion: The LightGBM model showed the best performance in predicting postoperative lung function.

• Analytical Science and Technology
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• v.19 no.1
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• pp.96-102
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• 2006

Trimethylamine (TMA) is one of the difficult odorous compounds for the collection and analysis. Although sulfuric acid absorption and/or sulfuric acid impregnated filter method are commonly recommended for its sampling, these methods also suffer from difficulties involved in sample treatment and operational procedures. Hence, as an ancillary approach to measure TMA, we investigated the combination of bag sampling and SPME analysis for TMA measurements. For the purpose of our study, we investigated the following three subjects: 1) temporal variability of standard storage, 2) bag loss effect of TMS, and 3) TMA loss due to repetitive analysis of an identical bag sample. According to our storage test up to 7 or 20 dyas, TMA loss were found to occur up to 40 to 50% within relatively short period of up to 48 hrs depending on its concentration ranges. When the tests were made for bag loss by transferring TMA standards across different size bags, we were able to find that the extent of bag loss are not significant with 5 to 20% loss rate. Finally, the TMA sorptive loss via its exposure to SPME fiber was generally estimated to run from 2 to 3%.

• Analytical Science and Technology
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• v.19 no.6
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• pp.498-503
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• 2006

A type of dimethyl disulfide gas CRM in the ppb level was developed for the analysis of tracelevel odorous gas in environmental atmosphere. The concentration of dimethyl disulfide($(CH_3)_2S_2$) was $10{\mu}mol/mol$ level in the cylinder filled with nitrogen, 1500 psi. And the variability of the concentration for 2 years was about 0.14% due to the adsorption or instability of $(CH_3)_2S_2$. The gas standards produced simultaneously in 4 bottles and examined by GC-FID were shown with 0.4%, reproducibility of preparation and 0.25%, standard uncertainty due to weighing and purity. The relative expended uncertainty of 1.1%(95% of confidence level, k=2) was assigned to the certified value of $10{\mu}mol/mol$ level of $(CH_3)_2S_2$ after quantitative evaluation on the purity, mixing, weighing, analysis, adsorption and stability of dimethyl sulfide gas.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5A
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• pp.691-697
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• 2008

Coating the high tension bolted frictional joint has been generally allowed for anti-corrosion purpose. However in case of painting on paying surface of the high tension bolt, the influence on a slip strength of the joint depending on precision of painting has remained controversial. The study thus was intended to identify the slip behavior on high tension bolted frictional joint when applying ceramic painting, which has been currently developed. A slip test was conducted on a high tension bolted frictional joint specimen on which ceramic painting has been applied and a slip load and slip coefficient were measured. Based on result, the safety and usability of ceramic painting-applied high tension bolted frictional joint was evaluated. As a result, a difference to some extent by specimen in terms of load-displacement when a slip occurred was observed but an average slip coefficient appeared to have exceeded 0.4, which is the design frictional coefficient set forth in the specification. To secure the safety and usability of ceramic painting-applied high tension bolted frictional joint, it's necessary to establish the standard for painting as well as to revise the relevant specification.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4D
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• pp.687-693
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• 2006

Image co-registration is the process of overlaying two images of the same scene, one of which represents a reference image, while the other is geometrically transformed to the one. In order to improve efficiency and effectiveness of the co-registration approach, the author proposed a pre-qualified area matching algorithm which is composed of feature extraction with canny operator and area matching algorithm with cross correlation coefficient. For refining matching points, outlier detection using studentized residual was used and iteratively removes outliers at the level of three standard deviation. Throughout the pre-qualification and the refining processes, the computation time was significantly improved and the registration accuracy is enhanced. A prototype of the proposed algorithm was implemented and the performance test of 3 Landsat images of Korea. showed: (1) average RMSE error of the approach was 0.435 pixel; (2) the average number of matching points was over 25,573; (3) the average processing time was 4.2 min per image with a regular workstation equipped with a 3 GHz Intel Pentium 4 CPU and 1 Gbytes Ram. The proposed approach achieved robustness, full automation, and time efficiency.

• Journal of Korea Entertainment Industry Association
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• v.13 no.8
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• pp.435-446
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• 2019

The purpose of this study was to investigate the effect of strength exercise program(60 minutes/day, 3 times/week) on health-related fitness and the factor of metabolic syndrome in the older at senior care facilities during 12 weeks. Twenty-seven volunteers were recruited for the study and divided into two groups: 15 persons(82.6yrs) undertook a continuous 12 weeks strength exercise program(EG), and 12 persons(78.9yrs) served as a control group(CG). The data process of this study calculated as mean(M) and standard Deviation(SD) of all measured value, used repeated measure ANOVA, and paired t-test. The significant level of hypothesis verification is set-up as α=.05. After 12 weeks in EG, health-related fitness increased by an average of 15.2% for right grip strength(p<.05), 26.9% for left grip strength(p<.05), 32.7% for chair stand(p<.05), 92.5% for one leg stand(p<.05), 29.6% for sit and reach(p<.05), and 34.5% for TUG(p<.05); CG showed no difference between pre and post. In the factor of metabolic syndrome, Systolic BP(3.1mmHg) and fasting blood glucose(7.4mg/dl) decreased in the EG group(p<.05). In summary, the strength exercise program leads to a genuine increase in health-related fitness and decrease in the factor of metabolic syndrome in the older adults. The well planned strength exercise seems to be an important intervention to improve function fitness in this population.