• Korean Journal of Child Studies
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• v.37 no.6
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• pp.107-117
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• 2016

Objective: This study examined the construct validity of K-WPPSI-IV. Factor structures of the structures of the K-WPPSI-IV full scale as well as primary index scales for two age ranges (2 years, 6 months to 3 years, 11 months; 4 years to 7 years, 7 months) were examined. Methods: Data were collected from 1,700 children aged 2 years, 6 months to 7 years, 7 months during the K-WPPSI-IV standardization. Confirmatory factor analyses were conducted using the K-WPPSI-IV subtest performances with maximum likelihood estimation using Amos 18. Results: First, the three-factor model (verbal comprehension, visual spatial, and working memory) fitted best for the younger age range. However, the five-factor model (verbal comprehension, visual spatial, fluid reasoning, working memory, and processing speed) fitted best for the older age range. Residuals suggest the presence of two nested subfactors within the verbal comprehension factor (broad/expressive and focused/simple). Second, the confirmatory factor analysis on primary index subtests identified factors that account for the intercorrelations among the reduced sets of primary index subtests. Conclusion: The findings showed that the theoretical structures of WPPSI-IV subtests were confirmed within K-WPPSI-IV.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.806-809
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• 2004

The early-age cracks have bad effects on the diffusion movement of chloride ions and oxygen. In this study, a corrosion analysis algorithm for cracked concrete is proposed to examine the influence of early-age cracks on corrosion of RC structures. For different environmental exposure conditions of RC structures, a corrosion model is combined with models for activation polarization and concentration polarization. From the finite element corrosion analysis using the proposed algorithm and the models, the effects of early-age cracks to the corrosion is simulated.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.361-366
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• 1999

The purpose of this study is to evaluate the structural performance of Reinforced steel fiber concrete structures using early age concrete. Reinforced concrete structures using early age concrete are result in the degradation of structural performance due to crack, overload, unexpected vibration and impact load. Specimens, designed by the over 0.75% of steel fiber incorporated, were showed the ductile behavior and failed slowly with flexure and flexure-shear. Increasing the percent of steel fiber incorporated(0.25~2.0%), the ultimate shear stress of each specimen were increased 12~40% than that of specimen SSS.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.15 no.1
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• pp.21-26
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• 1985

The author observed 97 cases ameloblastoma diagnosed in Department of Oral Radiology in Seoul National University and analyzed patient's age, sex, location, relation with adjacent anatomic structures, and radiographic forms. The obtained results are as follows: 1. The average age of patients was 28.7 years. The mean age of male was 28.5 years, and female's 30.0 years. Third decades revealed highest rate. 2. The occurrence of ameloblastoma is approximately evenly distributed in both sexes, male 46 cases (47.2%), female 51 cases (52.6%). 3. Ninty-five (98.0%) cases occurred in the mandible. The mandibular molar-ramus region was the most frequent site of the tumor (74 cases, 76.3%). 4. Most of the cases affected adjacent anatomic structures. 24 cases (24.7%) were shown to be definitely associated with an impacted tooth. 5. Radiographic forms are unilocular (29 cases, 29.3%), honeycomb (17 cases, 17.5%), and multilocular (67 cases, 69.1%) radiolucencies.

• Journal of Medicine and Life Science
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• v.15 no.2
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• pp.84-88
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• 2018

The aim was to evaluate different results from using crude incidence rate (CIR) instead of agestandardized incidence rate (AIR) when comparing groups having different age structures. After selecting a report using CIRs, AIRs and their 95% confidence intervals(CI) was calculated from the raw data. The statistically significant difference between CIR and AIR was decided based on AIR's 95% CI. Comparing with CIRs, AIRs were under-estimated. In addition, there were no statistical significance of annual trends(P=0.59). These findings are an additional evidence using AIR when comparing level of occurring infectious diseases on groups with different age structures.

• Economic and Environmental Geology
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• v.3 no.1
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• pp.9-15
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• 1970

This paper describes the definition of the Ogcheon Group and its characters, and indicates that it is neither the Precambrian nor metamorphosed Cambro-Ordovician sediments, and its geological age might fall in Post-Ordovician on the bases of lithostratigraphy, correlation and geological structures.

• Applied Microscopy
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• v.28 no.3
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• pp.255-262
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• 1998

This study was performed to observe the morphological changes of the synaptic structures in the interpolar part of the spinal trigeminal nucleus of rat during aging. Transmission electron microscopy has been used to determine the r)umber of synapses, length of postsynaptic densities, number and area of axon terminals. Sprague-Dawley rat 3, 12, 24 and 36 months of age were used in this study. 1. The number of synapses was 51.7, 43.1, 28.4 and 16.8 in the 3, 12, 24 and 36 months of age respectively. Therefore, the number of synapses decreased gradually with age, but decreased significantly in the 24 and 36 months. 2. The length of postsynaptic densities was $30.2{\mu}m,\;23.6{\mu}m,\;10.4{\mu}m\;and\;4.9{\mu}m$ in the 3, 12, 24 and 36 months of age respectively. Therefore, the length of postsynaptic densities decreased gradually with age, but decreased significantly in the 24 and 36months. 3. The number of axon terminals was 84.3, 73.7, 51.4 and 26.6 in the 3, 12, 24 and 36 months of age respectively. Therefore, the number of axon terminals decreased gradually with age, but decreased significantly in the 24 and 36months. 4. The area of axon terminals was $76.1{\mu}m^2,\;64.1{\mu}m^2,\;29.9{\mu}m^2\;and\;13.8{\mu}m^2$ in the 3, 12, 24 and 36 months of age respectively. Therefore, the area of axon terminals decreased gradilally with age, but decreased significantly in the 24 and 36 months. The results suggest that there are the changes of the synaptic structures in the interpolar part of spinal trigeminal nucleus of rat during aging. These changes nay be concerned to the decreased function of mediating pain and temperature sensation in the face and oral cavity during aging.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.429-432
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• 2008

Large area members such as foundation concrete of underground structures in power plants have an effect on structural stability and durability of the structure due to danger of crack occurrence and shrinkage crack that occur owing to the difference of temperature by heat of hydration between inside and outside of the members at initial age. And a construction for waterproofness is performed additionally to protect marine structures from osmosis of seawater because the structures adjoin below the surface of sea. So, if a rise of the heat of hydration, crack, and corrosion of bars are controled effectively using a composite such as fluosilicate salt in concrete production process of a initial construction, expenses are cut down and construction hours are reduced by securing durability through improvement of watertightness. The property tests of adiabatic temperature by hydration are carried out at initial age about standard concrete and test concrete using a fluosilicate salt composite to evaluate an effect on improvement of watertightness for concrete structures in this study. And the experiments such as a permeability test of hardened concrete, a water absorption test, a compression strength test and a elongation test are carried out and the results from these are described.

• International journal of advanced smart convergence
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• v.9 no.2
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• pp.203-211
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• 2020

This study proposes a method for estimating gender and age that is robust to various external environment changes by applying deep learning-based learning. To improve the accuracy of the proposed algorithm, an improved CNN network structure and learning method are described, and the performance of the algorithm is also evaluated. In this study, in order to improve the learning method based on CNN composed of 6 layers of hidden layers, a network using GoogLeNet's inception module was constructed. As a result of the experiment, the age estimation accuracy of 5,328 images for the performance test of the age estimation method is about 85%, and the gender estimation accuracy is about 98%. It is expected that real-time age recognition will be possible beyond feature extraction of face images if studies on the construction of a larger data set, pre-processing methods, and various network structures and activation functions have been made to classify the age classes that are further subdivided according to age.

• Structural Engineering and Mechanics
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• v.72 no.6
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• pp.737-746
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• 2019

Concrete mechanical properties change constantly with age, temperature, humidity and the other environmental factors. This research studies the effects of temperature and age on the development of concrete elastic modulus by a series of prism specimens. Elastic modulus test was conducted at various temperatures and ages in the laboratory to examine the effects of temperature and age on it. The experimental results reveal that the concrete elastic modulus decreases with the rise of temperature but increases with age. Then, a temperature coefficient K is proposed to describe the effects of temperature and validated by existing studies. Finally, on the basis of K, analytical models are proposed to determine the elastic modulus of concrete at a given temperature and age. The proposed models can offer designers an approach to obtain more accurate properties of concrete structures through the elastic modulus modification based on actual age and temperature, rather than using a value merely based on laboratory testing.