• The Journal of the Convergence on Culture Technology
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• v.6 no.2
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• pp.183-190
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• 2020

This study was designed to investigate the current state of lens wearing and care, and to investigate eye discomfort according to the care method. Data of 209 female college students wearing lenses for more than 1 year were analyzed using the SPSS / WIN 22.0 program. 40.2% of female students wear lenses every day and 97.1% wear all day. However, only 45.4% of students washed it daily, and only 17.7 % used protein remover during wash, which resulted in poor management. 98.1% of students complained of discomfort due to the lens, and the Ocular Surface Index (OSDI) scored 42.88 ± 15.25, which was classified as a severe dry eye and threatened eye health. Therefore, it is necessary to improve students' awareness of lens management, and periodical lens inspection and management education are needed.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.6
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• pp.7-14
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• 2017

This study manufactured a minimum quantity lubrication (MQL) supply system and identified the optimal MQL machining cutting conditions for plastic mold steel (SCM440). A series of experiments were consisted of twice. Optimal cutting conditions were derived using the Taguchi method, and cutting force variance; surface roughness; tool wear; and cutting temperature in dry, wet, and MQL machining were measured experimentally for these optimal conditions. The measured results decreased from dry to wet and MQL machining, being particularly large for dry machining due to increased cutting time. Measured MQL machining metrics were similar to those for wet machining, particularly for surface roughness, which is an index of machining quality.

• Journal of Korean society of Dental Hygiene
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• v.22 no.5
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• pp.333-340
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• 2022

Objectives: This study aimed to confirm the association between cognitive function and oral health status in the elderly. Methods: In this study, 5,794 respondents, aged 55 or older, who had participated in the 7th aging research panel survey were used. Statistical analyses were performed using a complex samples cross-tabulation analysis, complex samples general linear model, and a complex sample multinomial logistic regression analysis. Results: After analyzing the cognitive function of the elderly according to their oral health conditions, it was found that suspicions of dementia (19.6%) and cognitive function decline (25.9%) were more common for those who wore dentures than for those who did not wear dentures (p<0.001). Compared to those who did not wear dentures, those who wore dentures were linked to a 1.665 times higher suspicion of dementia (p<0.001). In comparison, cognitive decline was 0.964 times lower when the number of natural teeth increased by 1, and it was 0.941 times lower when the oral health evaluation index for the elderly increased by 1 point (p<0.001). Conclusions: As a result of this study, it was confirmed that cognitive function and oral health status are related in the elderly. Therefore, systematic measures for oral health management and oral health promotion should be prepared in tandem with awareness of possible cognitive decline in the elderly.

• Tunnel and Underground Space
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• v.33 no.6
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• pp.594-609
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• 2023

TBM (Tunnel Boring Machine) method is gaining popularity in urban and underwater tunneling projects due to its ability to ensure excavation face stability and minimize environmental impact. Among the prominent models for predicting disc cutter life, the NTNU model uses the Cutter Life Index(CLI) as a key parameter, but the complexity of testing procedures and rarity of equipment make measurement challenging. In this study, CLI was predicted using multiple linear regression analysis and tree-based machine learning techniques, utilizing rock properties. Through literature review, a database including rock uniaxial compressive strength, Brazilian tensile strength, equivalent quartz content, and Cerchar abrasivity index was built, and derived variables were added. The multiple linear regression analysis selected input variables based on statistical significance and multicollinearity, while the machine learning prediction model chose variables based on their importance. Dividing the data into 80% for training and 20% for testing, a comparative analysis of the predictive performance was conducted, and XGBoost was identified as the optimal model. The validity of the multiple linear regression and XGBoost models derived in this study was confirmed by comparing their predictive performance with prior research.

• Korean Journal of Human Ecology
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• v.18 no.5
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• pp.1087-1092
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• 2009

From the environmental adaptation point of view, the clothing habits made by the thermal sensation and clothing weight of elderly women have changed according to the thermal sensation and health condition. The purpose of this study was to obtain the basic data for developing healthy and comfortable clothing for elderly women. Clothing weight, thermal sensation, clothing microclimate, resistance to cold and heat of 198 elderly women in Taejeon were surveyed from October 9, 2007 to October 19, 2007. 1. Clothing weight per body surface area was $830.4g/m^2$ of total clothing weight, $242.8g/m^2$ of underwear clothing weight, $617.3g/m^2$ of outerwear clothing weight, $419.8g/m^2$ of upper clothing weight, and $420.4g/m^2$ of lower clothing weight. 2. More than 90% of the respondents replied that they felt comfortable when the temperature inside the clothing was $33.5^{\circ}C$ and humidity inside the clothing was 30.2%. 3. The elderly women were more sensible to cold than to hot, those who felt cold had a tendency to wear heavier clothing. 4. The appeal rate for physical pain of older and lower income people, especially those with an income under 1,000,000 won, was higher than that of others. On the other hand, the lower the subjective economic level, the younger they were, and the more the monthly average income was, the higher the rate of mental pain. 5. The heavier the total clothing weight was, the higher the appeal rate for general pain.

• Archives of Craniofacial Surgery
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• v.15 no.2
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• pp.47-52
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• 2014

Background: Management of positional plagiocephaly by wearing a cranial molding helmet has become a matter of growing medical interest. Some research studies reported that starting helmet therapy early (age 5 to 6 months) is important and leads to a significantly better outcome in a shorter treatment time. The aim of the present study was to evaluate the effectiveness of cranial remodeling treatment with wearing helmet for older infants (${\geq}18$ months). Methods: We conducted a retrospective study of 27 infants with positional plagiocephaly without synostosis, who were started from 2008 to 2012. Every child underwent a computerized tomography (CT) before starting helmet therapy to exclude synostosis of the cranial sutures and had CT performed once again after satisfactory completion of therapy. Anthropometric measurements were taken on using spreading calipers in every child. The treatment effect was compared using cranial vault asymmetry (CVA) and the cranial vault asymmetry index (CVAI), which were obtained from diagonal measurements before and after therapy. Results: The discrepancy of CVA and CVAI of all the patients significantly decreased after cranial molding helmet treatment in older infants (${\geq}18$ months) 7.6 mm from 15.6 mm to 8 mm and 4.51% from 9.42% to 4.91%. Six patients had confirmed successful outcome, and all subjects were good compliance patients. The treatment lasted an average of 16.4 months, was well tolerated, and had no complication. Additionally, the rate of the successful treatment (final CVA ${\leq}5mm$) significantly decreased when the wearing time per was shorter. Conclusion: This study showed that treatment by cranial remodeling orthosis was effective if the patient could wear the helmet longer and treatment duration was somewhat longer than in younger patients, well tolerated in older infants and had no morbidity. This therapeutic option is available and indicated in these older infants before other cranial remodeling surgery.

• Journal of the Korean Society of Clothing and Textiles
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• v.31 no.1 s.160
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• pp.33-43
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• 2007

Middle age is the time of the most important meaning in life and also the time of physical and mental change, which offers new social activities for self-development. Middle-aged women form the major consumer class in current clothing industry, but few have been performed on this so far. The researcher studied in many aspect on the clothes which middle-aged women need to wear during this period of change. Thus this study is executed to examine what benefits middle-aged women pursue in clothing attitudes and the relationship among clothing pursuit benefit and their somatotype compensation and image orientation. The research performed the theoretical study and practical study simultaneously. The subjects are 238 middle-aged women between 35 and 49 years old in September, 2004. The results of this study are as follows: 1. The attitude of women's clothing patterns in relation with image consist of two factor structures. One is the body image and the other is the appearance image. 2. As a result of researching the attitude for choosing clothes of each body group by Rohrer index, the women with gross body group take a top priority for the lower-body compensation, while the women with slim body group take a top priority for volume compensation. 3. As a result of researching the cognitive somatotype group's attitude for choosing clothes, gross body group takes a top priority for lower-body compensation and upper-body compensation. 4. As a result of researching the relationship between real somatotype and cognitive somatotype by Rohrer index, middle-aged women think of themselves as being fatter than present state. And choosing the clothes, the body misunderstanding group of women usually show that they consider more compensation than the normally body understanding group. 5. The evaluation on real somatotype, cognitive somatotype, ideal somatotype influences on the body cathexis.

• Journal of Distribution Research
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• v.17 no.2
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• pp.93-115
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• 2012

This study empirically examines the impact of changes in market shares among retailing types on the price index. The retailing type is classified into 6 groups: department store, big mart, super market, convenient store, specialty merchant, and on-line store. The market shares of retailing types are calculated by the ratio of each retailing type monthly sales to total monthly retailing sales in which total retailing sales is the sum of each retailing type sales. We employed several price indices: consumer price index (CPI), CPI for living necessaries, and fresh food price index. In addition, this study used fundamental price indices based on 25 product families as well as 42 representative products. The empirical model also included several variables in order to control for the macroeconomic effects and those variables are the exchange rate, M1, an oil price, and the industrial production index. The data is monthly time-series data spanning over the period from January 2000 to December 2010. In order to test for the stability of data series, we conducted ADF test and PP test in which the model and length of lag were determined by the relevant previous literature and based on the AIC. The empirical results indicate that changes in market shares among retailing types have impacts on the price index. Table A shows that impacts differ as to which price index to use and which product families and products to use. For department store, it lowers the price of food and non-alcoholic beverages, home appliances, fresh food, fresh and vegetables, but it keeps the price high for fresh fruit. The big mart retailing type has a positive impact on the price of food, nut has a negative effect on clothing and foot wear, non-food, and fresh fruit. For super market, it has a positive impact on food and non-alcoholic beverages, fresh food, fresh shellfishes, but increases the price of CPI for living necessaries and non-food. The specialty merchant retailing type increases the price level of CPI for living necessaries and fresh fruit. For on-line store type, it keeps the price high for CPI for living necessaries and non-food as well as fresh fruit. For the analysis based on 25 product families shows that changes in market shares among retailing types also have different effects on the price index. Table B summarizes the different results. The 42 representative product level analysis is summerized in Table C and it indicates that changes in market shares among retailing types have different effects on the price index. The study offers the theoretical and practical implication to these findings and also suggests the direction for the further analysis.

• Journal of Oral Medicine and Pain
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• v.23 no.4
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• pp.419-432
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• 1998

The purpose of this Study was to examine the efficacy and compliance of a mandibular advancement device(MAD) according to the severity of sleep apnea in the snorers and obstructive sleep apnea patients. Fifty-four patients (45 males, 9 females, aged 20 - 68years ) who visited Seoul National Uiversity Dental Hospital(SNUDH) to seek for the treatment of snoring and sleep apnea were classified into four groups according to the results of the nocturnal polysomnography and they were instructed to wear MAD regularly which was designed to increase the size of the upper airway by advancing the mandible. The evaluation of the efficacy and compliance of the MAD according to the severity of apnea and the duration after the usage of MAD ( 1week, 1month, 3months, 6months, 12months) was made by using quesionnaires mad in Department of Oral Medicine and Oral diagnosis, SNUDH. The obtained results were as follows : 1. All subjects results were habitual snoreres and 43 patients(79.6%) complained the loudness of snoring that can be heard out of the room. 2. Apnea index(AI) of the total subjects was mean 29.4$\pm$26.9 and respiratory disturbance index(RDI)was mean 37.6$\pm$28.0. And there was nodifference in the efficacy and the compliances of MAD according to the severity of apnea. 3. The severityi of apnea by the questionnaires significantly corresponded with the results of nocturnal polysomnography, and this fact potentiated the diagnostic value of the questionnaire. 4. after the usage of MAD, there was significant improvement in the frequency of snoring, the loudness of snoring, frequency of apnea, daytime sleepiness nad the refreshment after sleep(p<0.001) regardless of the apnea index(AI) and respiratory distrubance index(RDI). 5. The degree of the satisfaction with MAD was mean 74.4$\pm$18.4% and that of the discomfort with the MAD was 31.4$\pm$19.6%. But there was no serious complication in occlusion and temporomandibular joint with the usage of MAD and the duration of the discomfort was mean 3.3$\pm$2.2 weeks. 6. Forty-one patients(75.9%) continued the usage of MAD but thirteen patients(24.1%) stopped the use of MAD because of the discomforts and insufficient results with it.

• Journal of Korean Vacuum Science & Technology
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• v.6 no.2
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• pp.105-107
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• 2002

a-C:H films were coated on windows of mobile telephone by RF plasma chemical vapor deposition equipment made in our company. Thickness of the coatings is about 0.7 micrometers and they have high hardness, low friction coefficient, good adhesion, high optical transparency and chemical inertness. Knoop hardness of the diamond-like carbon films on glass substrate is 2328 kg/mm$^2$. The adherence between films and substrate is good and shows to be 69 N by scratching test. The optical performance is improved obviously owing to coat the film on it. The index of the coated windows is 2.5, transmission of visible light is larger than 90%, and transmission of ultraviolet light decreases by 30% and the ultraviolet light can be obstructed obviously. The coated glass also has self-clean effect and decontamination ability. The films have hydrophobic character and the soakage angle of water drop is larger than 90 degrees. The windows have fog-proof ability owing to eliminate the capillary phenomena in the inner surface. The physics and chemical properties of the coated windows are steady. Study indicates that the performance of a-C:H coated mobile phone windows are improved notably on wear-resistance, corrosion-proof and optical properties and it is excellent mobile windows protective coatings.