• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.42.1-42
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• 2002

A model to predict population by sex, age and district over a long-range period is proposed based on fuzzy theories. First, a fuzzy model is described. Second, a method to estimate the social increase by sex and age in each district is proposed based on a fuzzy clustering method for dealing with long-range socioeconomic changes in population migration. By the proposed methods, it became possible to predict the population by sex, age and district over a long-range period. Third, the structure and characteristics of the three models of employment model, time distance model, and land use model constructed to predict various socioeconomic indicators, which are require...

• Korean Journal of Radiology
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• v.24 no.11
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• pp.1151-1163
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• 2023

Objective: To develop a deep-learning-based bone age prediction model optimized for Korean children and adolescents and evaluate its feasibility by comparing it with a Greulich-Pyle-based deep-learning model. Materials and Methods: A convolutional neural network was trained to predict age according to the bone development shown on a hand radiograph (bone age) using 21036 hand radiographs of Korean children and adolescents without known bone development-affecting diseases/conditions obtained between 1998 and 2019 (median age [interquartile range {IQR}], 9 [7-12] years; male:female, 11794:9242) and their chronological ages as labels (Korean model). We constructed 2 separate external datasets consisting of Korean children and adolescents with healthy bone development (Institution 1: n = 343; median age [IQR], 10 [4-15] years; male: female, 183:160; Institution 2: n = 321; median age [IQR], 9 [5-14] years; male: female, 164:157) to test the model performance. The mean absolute error (MAE), root mean square error (RMSE), and proportions of bone age predictions within 6, 12, 18, and 24 months of the reference age (chronological age) were compared between the Korean model and a commercial model (VUNO Med-BoneAge version 1.1; VUNO) trained with Greulich-Pyle-based age as the label (GP-based model). Results: Compared with the GP-based model, the Korean model showed a lower RMSE (11.2 vs. 13.8 months; P = 0.004) and MAE (8.2 vs. 10.5 months; P = 0.002), a higher proportion of bone age predictions within 18 months of chronological age (88.3% vs. 82.2%; P = 0.031) for Institution 1, and a lower MAE (9.5 vs. 11.0 months; P = 0.022) and higher proportion of bone age predictions within 6 months (44.5% vs. 36.4%; P = 0.044) for Institution 2. Conclusion: The Korean model trained using the chronological ages of Korean children and adolescents without known bone development-affecting diseases/conditions as labels performed better in bone age assessment than the GP-based model in the Korean pediatric population. Further validation is required to confirm its accuracy.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.123-128
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• 1999

Recently, as a performance based design concept is introduced, assurance of expected performances on serviceability and safety in the whole span of life is exactly requested. So, quantitative assessments about durability related properties of concrete in early-age long term are come to necessary, Especially in early age, deterioration which affects long-term durability performance can be occurred by hydration heat and shrinkage, so development of reasonable hydration heat model which can simulate early age behavior is necessary. The micor-pore structure formation property also affects shrinkage behavior in early age and carbonations and chloride ion penetration characteristic in long term, So, for the quantitative assessment on durability performance of concrete, modelings of early age concrete based on hydration process and micor-pore structure formation characteristics are important. In this paper, a micromechanics based hydration heat evolution model is adopted and a quantitative model which can simulate micro-pore structure development is also verified with experimental results. The models can be used effectively to simulate the early-age behavior of concrete composed of different mix proportions.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.4
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• pp.127-132
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• 2014

Some laws and regulations may require internet service providers to provide services based on the age of users. Age verification in the online environment should be used as a tool to provide service that is appropriate to child based on age. Using the minimum attribute information, processes on age verification provides the proper guidance to the internet services. However, there is a lack of a globally accepted trust framework for age verification process including evaluation factors for age verification information. In this paper the federation model of user attributes were described and evaluation factors for the age verification information were suggested. Also using the suggested evaluation factors, performance evaluation of federation model of user evaluation was performed. To meet the requirements of evaluation factors, framework of federation model should consider the unlinkability pseudonym support, eavesdropping protection and cloning protection.

• Korean Journal of Radiology
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• v.22 no.12
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• pp.2017-2025
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• 2021

Objective: To evaluate the accuracy and clinical efficacy of a hybrid Greulich-Pyle (GP) and modified Tanner-Whitehouse (TW) artificial intelligence (AI) model for bone age assessment. Materials and Methods: A deep learning-based model was trained on an open dataset of multiple ethnicities. A total of 102 hand radiographs (51 male and 51 female; mean age ± standard deviation = 10.95 ± 2.37 years) from a single institution were selected for external validation. Three human experts performed bone age assessments based on the GP atlas to develop a reference standard. Two study radiologists performed bone age assessments with and without AI model assistance in two separate sessions, for which the reading time was recorded. The performance of the AI software was assessed by comparing the mean absolute difference between the AI-calculated bone age and the reference standard. The reading time was compared between reading with and without AI using a paired t test. Furthermore, the reliability between the two study radiologists' bone age assessments was assessed using intraclass correlation coefficients (ICCs), and the results were compared between reading with and without AI. Results: The bone ages assessed by the experts and the AI model were not significantly different (11.39 ± 2.74 years and 11.35 ± 2.76 years, respectively, p = 0.31). The mean absolute difference was 0.39 years (95% confidence interval, 0.33-0.45 years) between the automated AI assessment and the reference standard. The mean reading time of the two study radiologists was reduced from 54.29 to 35.37 seconds with AI model assistance (p < 0.001). The ICC of the two study radiologists slightly increased with AI model assistance (from 0.945 to 0.990). Conclusion: The proposed AI model was accurate for assessing bone age. Furthermore, this model appeared to enhance the clinical efficacy by reducing the reading time and improving the inter-observer reliability.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.411-414
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• 2007

The confinement-shear lattice(CSL) model for hardened concretes developed by Cusatis is extended for early age concretes. The uniaxial behaviors available in the literature for 3 to 28 days were simulated by the CSL model to identify the change of the model parameters for various ages. The change with respect to the age was interpolated based on the chemomechanics to develop the extended version of CSL model.

• Computers and Concrete
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• v.5 no.4
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• pp.295-328
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• 2008

A previously published multiscale model for early-age cement-based materials [Pichler, et al.2007. "A multiscale micromechanics model for the autogenous-shrinkage deformation of early-age cement-based materials." Engineering Fracture Mechanics, 74, 34-58] is extended towards upscaling of viscoelastic properties. The obtained model links macroscopic behavior, i.e., creep compliance of concrete samples, to the composition of concrete at finer scales and the (supposedly) intrinsic material properties of distinct phases at these scales. Whereas finer-scale composition (and its history) is accessible through recently developed hydration models for the main clinker phases in ordinary Portland cement (OPC), viscous properties of the creep active constituent at finer scales, i.e., calcium-silicate-hydrates (CSH) are identified from macroscopic creep tests using the proposed multiscale model. The proposed multiscale model is assessed by different concrete creep tests reported in the open literature. Moreover, the model prediction is compared to a commonly used macroscopic creep model, the so-called B3 model.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.7
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• pp.2480-2495
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• 2014

This paper describes a hierarchical method for image-based age estimation that combines age group classification and age value estimation. The proposed method uses a coarse-to-fine strategy with different appearance features to describe facial shape and texture. Considering the damage to continuity between neighboring groups caused by fixed divisions during age group classification, a dynamic grouping technique is employed to allow non-fixed groups. Based on the given group, an ordinal hyperplane ranking (OHRank) model is employed to transform age estimation into a series of binary enquiry problems that can take advantage of the intrinsic correlation and ordinal information of age. A set of experiments on FG-NET are presented and the results demonstrate the validity of our solution.

• Architectural research
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• v.15 no.4
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• pp.175-182
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• 2013

This study aims to explore age-related differences with the assessment tools in the web-based 3D virtual model house and to propose the 3D model house criteria which everyone can use easily. The participants came from three age groups, ranging from their 20s to their over 40. Presence, Usability and Space perception and cognition in the experiment for navigating and evaluating the web-based 3D model house were measured and compared through one-way ANOVA and two-way ANOVA. The results and conclusions are as follows. (1) The younger the participants were, the more positive they evaluated the experiment on Presence. However, 20s needed higher presence than other two groups. (2) 30s and over 40 groups evaluated that the 3D virtual model house was more efficient than an actual model house on Usability. When the participants were younger, the values of 'expressivity' factor were higher. (3) The younger the participants were, the more positive they perceived the virtual environment (VE) on Space perception and cognition scale. There were no significant differences in the selection of dwelling size and the floor plan type. There were no significant differences of interaction effects between age and online gaming experience on Presence and Usability. The results of the current study demonstrate that there are differences among age groups and older groups have difficulty navigating and assessing in a VE. Although older groups take longer to adapt in the VE, they regard the 3D model house as an effective tool for purchase of house.

• Journal of Radiation Protection and Research
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• v.46 no.4
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• pp.170-177
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• 2021

Background: The International Commission on Radiological Protection is preparing to provide reference dose coefficients for environmental radioiodine intake based on newly developed age-specific biokinetic models. However, the biokinetics of iodine has been reported to be strongly dependent on the dietary intake of stable iodine; for example, the thyroidal uptake of iodine may be substantially lower in iodine-rich regions than in iodine-deficient regions. Therefore, this study attempted to establish a system of age-specific thyroid dose estimation for South Koreans, whose daily iodine intakes are significantly higher than that of the world population. Materials and Methods: Korean age-specific biokinetic parameters and thyroid masses were derived based on the previously developed Korean adult model and the Korean anatomical reference data for adults, respectively. This study complied with the principles used in the development of age-specific biokinetic models for world population and used the ratios of baseline values for each age group relative to the value for adults to derive age-specific values. Results and Discussion: Biokinetic model predictions based on the Korean age-specific parameters showed significant differences in iodine behaviors in the body compared to those predicted using the model for the world population. In particular, the Korean age-specific thyroid dose coefficients for ¹²⁹I and ¹³¹I were considerably lower than those calculated for the world population (25%-76% of the values for the world population). Conclusion: These differences stress the need for Korean-specific internal dose assessments for infants and children, which can be achieved by using the data calculated in this study.