• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 가을 학술논문 발표대회
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• pp.61-62
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• 2021

Because of the problem of increasing self-weight due to the enlargement and high-rise of buildings using normal aggregate concrete, the need for structural lightweight aggregate concrete increases. However, early strength prediction is required when placing structural lightweight aggregate concrete, but research is insufficient. In this study, the ultrasonic pulse velocity of normal aggregate concrete and lightweight aggregate concrete was measured at early age. As a result, the ultrasonic pulse velocity of lightweight aggregate concrete was lower than normal aggregate concrete according to elapsed time at early age.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.55-56
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• 2023

Recently, large and high-rise buildings are increasing, and accordingly, concrete weight reduction is required. Lightweight aggregate concrete can provide economic feasibility and large space, but safety can be reduced due to problems such as low strength and poor durability. Since the development of such low strength of concrete is important in the early construction stage, it is necessary to evaluate the vertical formwork demolding period at the early age. The correlation was analyzed by measuring the compressive strength and ultrasonic pulse velocity. As a result, the ultrasonic pulse rates of normal and lightweight aggregate concrete at the time of 5 MPa expression, which is the time of vertical mold deformation, were 3.07 km/s and 2.77 km/s for W/B 41, and 2.89 km/s and 2.73 km/s for W/B 33.

• Journal of Korean Neurosurgical Society
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• 제57권4호
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• pp.276-282
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• 2015

Objective : The purpose of this study was to investigate morphological change at the craniovertebral junction (CVJ) region using computed tomography. Methods : A total of 238 patients were included in this study, and mean age was $47.8{\pm}21.3months$. Spinal canal diameter, Power's ratio, McRae line, antero-posterior C1 ring height, atlantoaxial joint space, C2 growth, epidural space from the dens (M-PB-C2) and longitudinal distance (basion to C2 lower margin, B-C2) were measured. The mean value of each parameter was assessed for individual age groups. The cohorts were then divided into three larger age groups : infancy (I) (${\leq}2years$), very early (VE) childhood (2-5 years) and early (E) childhood ($5{\geq}years$). Results : Spinal canal diameter increased with age; however, this value did not increase with statistical significance after VE age. A significant age-related difference was found for all C2 body and odontoid parameters (p<0.05). Mean McRae line was 8.5, 8, and 7.5 mm in the I, VE, and E groups, respectively. The M-PB-C2 line showed up-and-down dynamic change during early pediatric periods. Conclusion : Expansion of the spinal canal was restricted to the very early childhood period (less than 5 years) in the CVJ region; however, the C2 body and odontoid process increased continuously with age. The above results induced a dynamic change in the M-PB-C2 line. Although C2 longitudinal growth continued with age, the McRae line showed relatively little change.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표회 논문집(I)
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• pp.42-47
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• 1998

Experimental investigation was undertaken to determine early-age strength development and the relationships between the mechanical properties of type I, V and V/fly ash cement concrete with different curing temperature. The tests for mechanical properties, i.e., compressive strength, splitting tensile strength and modulus of elasticity were carried out for type, I, V and V with 15% replacement with fly ash cement concrete. For this purpose 480 concrete cylinders cured at isothermal conditions of 10, 23, 35 and 5$0^{\circ}C$ were tested at ages of 1, 3, 7 and 28days. According to the experiments, the concrete subjected to high temperature at early age got greater strength at early age, however eventually lower strength at late age. The derived relationships between compressive strength and splitting tensile strength and elastic modulus of elasticity appeared to be identical for all types of cement.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2010년도 춘계 학술논문 발표대회 2부
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• pp.51-52
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• 2010

In this study, it is confirmed that the use of equivalent age method can be applied to predict the early-age strength in case of using the new early strength concrete developed for the reduction of construction work period by our company, in apartment.

• 치위생과학회지
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• 제18권5호
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• pp.312-318
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• 2018

The purpose of this study was to evaluate the relationship between early menopause and periodontal disease in postmenopausal women using data from the 6th Korean National Health and Nutrition Examination Survey (2013~2015). A study was conducted with 2,048 postmenopausal women aged 45 to 74 years. Participants were divided into the early menopause group (menopause occurring at age 45 years or before) and normal menopause group (menopause occurring after age 45 years). A community periodontal index greater than or equal to code 3 was used to define periodontal treatment needs. A chi-square test was used to confirm the bivariate relationship between the variables. Multinomial logistic regression analysis was used to adjust for covariates (age, education, family income, body mass index, alcohol drinking, smoking, visiting dentist in the last year, use of oral care products, frequency of tooth brushing per day). The risk of periodontal disease was higher in the early menopause group after adjusting for potential confounders (odds ratio, 1.59). In particular, the relationship between early menopause and periodontal disease was more evident in women with low education and those who did not use oral care products. The findings of this study suggest that early menopause is a significant factor of periodontal disease in Korean women.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제22권1호
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• pp.41-49
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• 2019

Recent studies on pediatric inflammatory bowel disease (IBD) have revealed that early-onset IBD has distinct phenotypic differences compared with adult-onset IBD. In particular, very early-onset IBD (VEO-IBD) differs in many aspects, including the disease type, location of the lesions, disease behavior, and genetically attributable risks. Several genetic defects that disturb intestinal epithelial barrier function or affect immune function have been noted in these patients from the young age groups. In incidence of pediatric IBD in Korea has been increasing since the early 2000s. Neonatal or infantile-onset IBD develops in less than 1% of pediatric patients. Children with "neonatal IBD" or "infantile-onset IBD" have higher rates of affected first-degree relatives, severe disease course, and a high rate of resistance to immunosuppressive treatment. The suspicion of a monogenic cause of VEO-IBD was first confirmed by the discovery of mutations in the genes encoding the interleukin 10 (IL-10) receptors that cause impaired IL-10 signaling. Patients with such mutations typically presented with perianal fistulae, shows a poor response to medical management, and require early surgical interventions in the first year of life. To date, 60 monogenic defects have been identified in children with IBD-like phenotypes. The majority of monogenic defects presents before 6 years of age, and many present before 1 year of age. Next generation sequencing could become an important diagnostic tool in children with suspected genetic defects especially in children with VEO-IBD with severe disease phenotypes. VEO-IBD is a phenotypically and genetically distinct disease entity from adult-onset or older pediatric IBD.

• 한국생활과학회지
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• 제17권3호
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• pp.389-397
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• 2008

This study is investigating the perceptions of early childhood teachers on early childhood music activity. The subjects are early childhood teachers(N=217) working at kindergartens and day care centers in Jeonbuk Province. The data were collected from a questionnaire and analyzed with the tests of frequency, Cronbach's $\alpha$, t-test, ANOVA and Duncan. The results are as follow: first, the early childhood teachers are being aware of importance of infant music activity in the order of "aesthetic exploration", "artistic expression", and "art appreciation". Second, according to teachers' working place, the teachers have no differences of perception in early childhood music activities, while, according to children's age in the class which the teachers are taking charge of, they show differences of perception in the activities of "exploring movements " and "respect for artistic expression". Third, according to the early childhood teacher's career, they have difference of perception in "singing" activity only, while according to their education level, they have no differences of perception in all music activities. According to teachers' age, they have differences of perception in the activities of "aesthetic exploration", "exploring sound", and "singing".

• 한국의류학회지
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• 제21권1호
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• pp.144-154
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• 1997

For design of early childhood children's footwear, this study was to analyze the foot type by factor analysis and cluster analysis. This study was performed 200 male and 200 female early childhood children from 3 to 6 years, reported in part 1. The result was as follows : 1. There are no significant differences concerning significances, factor loading, eigenvalues, and contribution rates of factor among the results abtained by analyzing the male, female and both sexes data. 2. The 1st factor signifies the size factor that represents total foot mass. The average scores of the 1st factor significantly increase with age in both sexes, and those scores of male are significantly higher than those of female. 3. The End factor signifies the height of Tarsal, Heel and Arch. The average scores of the 2nd factor significantly increase with age in both sexes, and there are no significant differences between the average scores of male and female's except the age 3. 4. The 3rd factor signifies the shape of Metatarso-phalanx angle. The average scores of the 3rd factor significantly decrease with age in female. 5. There are four clusters selected by fastcluster in every age group. The characteristics of four clusters of every age group are different significantly.

• Asian Pacific Journal of Cancer Prevention
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• 제13권5호
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• pp.1767-1770
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• 2012

Background: The Asia Pacific consensus for colorectal cancer (CRC) recommends that screening programs should begin by the age of 50. However, there have been reports about increasing incidence of CRC at a younger age (i.e. early-onset CRC). Little is known about the features of early-onset CRC in the Vietnamese population. Aim: To describe the clinical, endoscopic and pathological characteristics of early-onset CRC in Vietnamese. Method: A prospective, cross-sectional study was conducted at the University Medical Center from March 2009 to March 2011. All patients with definite pathological diagnosis of CRC were recruited. The early-onset CRC group were analyzed in comparison with the late-onset (i.e. ${\geq}$ 50-year-old) CRC group. Results: The rate of early-onset CRC was 28% (112/400) with a male-to-female ratio of 1.3. Some 22.3% (25/112) of the patients only experienced abdominal pain and/or change in bowel habit without alarming symptoms, 42.9% (48/112) considering their symptoms intermittent. The rate of familial history of CRC in early-onset group was significantly higher that of the late-onset group (21.4% versus 7.6%, p<0.001). The distribution of CRC lesions in rectum, distal and proximal colon were 51.8% (58/112), 26.8% (30/112) and 21.4% (24/112), respectively; which was not different from that in the late-onset group (${\chi}2$, p = 0.29). The rates for poorly differentiated tumors were also not significantly different between the two groups: 12.4% (14/112) versus 8.3% (24/288) (${\chi}2$, p = 0.25). Conclusion: A high proportion of CRC in Viet Nam appear at an earlier age than that recommended for screening by the Asia Pacific consensus. Family history was a risk factor of early-onset CRC. Diagnosis of early-onset CRC needs more attention because of the lack of alarming symptoms and their intermittent patterns as described by the patients.