• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.2
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• pp.264-274
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• 2001

An integrated fatigue strength assessment system was computerized. The system developed consists of 9 modules: user interface, cycle counting, load history construction, data searching, fatigue properties estimation, fatigue data analysis, true stress and strain analysis, expert system for crack initiation life prediction, fatigue crack initiation and propagation life prediction. Fatigue strength database also was included in this system. The fatigue expert system helps a beginner to predict a fatigue crack initiation life in fatigue strength assessment. The expert system module in this system is developed on the personal computer by using C language and UNiK, an expert system developing tool. To evaluate the system, the results of test under variable loading of SAE and failure data from a field were analyzed. The evaluation show that the system provided fatigue life prediction within 3-scatter band and gave reasonable predictions. To get more accurate predictions of fatigue life without fatigue properties, we recommend utilizing the system along with the fatigue strength database.

• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.5.1-5.14
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• 2023

Background: Perfluoroalkyl substances (PFAS) are chemicals widely used in various products in everyday life. Due to its unique strong binding force, the half-life of PFAS is very long, so bioaccumulation and toxicity to the human body are long-standing concerns. In particular, effects on kidney function have recently emerged and there are no studies on the effect of PFAS on kidney function through epidemiological investigations in Korea. From 2018 to 2020, the Korean National Environmental Health Survey (KoNEHS) cycle 4, conducted an epidemiological investigation on the blood concentration of PFAS for the first time in Korea. Based on this data, the relationship between PFAS blood concentration and kidney function was analyzed for adolescents. Methods: We investigated 5 types of PFAS and their total blood concentration in 811 middle and high school students, living in Korea and included in KoNEHS cycle 4, and tried to find changes in kidney function in relation to PFAS concentration. After dividing the concentration of each of the 5 PFAS and the total concentration into quartiles, multivariable linear regression was performed to assess the correlation with kidney function. The bedside Schwartz equation was used as an indicator of kidney function. Results: As a result of multivariable linear regression, when observing a change in kidney function according to the increase in the concentration of each of the 5 PFAS and their total, a significant decrease in kidney function was confirmed in some or all quartiles. Conclusions: In this cross-sectional study of Korean adolescents based on KoNEHS data, a negative correlation between serum PFAS concentration and kidney function was found. A well-designed longitudinal study and continuous follow-up are necessary.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.9
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• pp.27-31
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• 2003

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.567-571
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• 1996

The objective of STEP is to provide neutral mechanism capable of describing product data through the life cycle of a product, independent form any particular systems. This paper describes an STEP application program that can display the three-dimensional shape based on b-spline surface and the data which defines configuration of the product. The developed program is based on the STEP part 203 “Configuration controlled design”.

• Convergence Security Journal
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• v.23 no.1
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• pp.109-115
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• 2023

The future outlook for defense faces various and challenging environments such as the acceleration of uncertainty in the global security landscape and limitations in domestic social and economic conditions. In response, the Ministry of National Defense seeks to address the problems and threats through defense innovation based on scientific and technological advancements such as artificial intelligence, drones, and robots. To introduce advanced AI-based technology, it is essential to integrate and utilize data on IT environments such as cloud and 5G. However, existing traditional security policies face difficulties in data sharing and utilization due to mainly system-oriented security policies and uniform security measures. This study proposes a paradigm shift to a data value-based security policy based on theoretical background on data valuation and life-cycle management. Through this, it is expected to facilitate the implementation of scientific and technological innovations for national defense based on data-based task activation and new technology introduction.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.3
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• pp.30-36
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• 2013

This paper presents a method to estimate a storage life for loss of stabilizer content as storage periods using accelerated life test data. The estimate of storage life based on deterministic accelerated life test and degradation data cannot describe a condition distribution and storage life distribution. Previously, the method to show the condition distribution and storage life distribution by using gamma process has been studied. But it has limitation because it is impossible to collect the deterioration data at initial production phase. The estimated storage life presented by this study shows the similar value to previous studies and the method can describe the condition distribution and storage life distribution. So, the estimation method studied in this paper can be used for a life cycle management about deterioration of propellant for propulsion unit or components of missile, too.

• Korean Journal of Human Ecology
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• v.1 no.2
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• pp.75-88
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• 1998

This study designed to explore the patterns of housing life-styles and the characteristics of apartment housing residents and to examine the relationships between housing life-styles and the characteristics of apartment-housing residents. The data for this study was collected by questionnaires administered to 278 homemakers living in apartment housing over 20s pyong(66$m^2$) in the Kwangju area. The major findings of this study can be summarized as follows; 1. Housing life-styles were grouped into 9 sub-categories : the Anbang-centered, the dining-centered, the pursuit of conspicuosness and conformity, orientation to change, the pursuit of orderliness, the pursuit of decoration, orientation to community, pursuit of individuality and the orientation to a natural environment. 2. Housing life-styles were significantly different according to age, educational background, and employment status of homemakers, occupation of the primary income provider, family-life cycle stage, total household income, and housing size. (Korean J Human Ecology 1(2):75~88. 1998)

• Journal of the Korean housing association
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• v.8 no.3
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• pp.59-66
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• 1997

The purpose of this study is to explore the relationships between the various types of activities occurring in domestic space and the resident's characteristics in Belgium. Data for this study was collected by questionnaires mailed to 133 staff member. both academic and administrative. working at The Free University of Brussels. a university serving the Dutch speaking community in Belgium. General leneal model and Duncan test were used in analyzing the data. The major findings of the study can be summarized as follows: First. families in the life-cycle stage of having no children are more likely to relax and watch T.V. and do housework in the master bedroom than those in the launching stage. Families in the life-cycle stage of elementary school are more likely to eat meals in the kitchen than those in the launching period. Second. families made up two members and under tend to do more housework in the master bedroom than those of three and over. Third. those with aged 30 and under are more likely to relax and watch T.V., and to do housework in the master bedroom than those with aged 51 and over. Forth. the renter status of homeownership tend to more relax and watch T.V., and to do housework in the master bedroom than the owner Fifth. those living with less floor space tend to relax and watch T.V. in the master bedroom more than those with larger residences.

• Korean Journal of Community Nutrition
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• v.7 no.1
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• pp.130-140
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• 2002

The purpose of this study was to examine the customer’s perception of the importance of restaurant quality by using a developed SERVQUAL model. In particular, it was intended to provide the basic information for nutrition education for family’s eating out. the data were collected through the survey over 440 families who have lived around the apartments in Kyongju and Seoul. The structure questionnaire included 35 items evaluating the quality of restaurants, adapting SERVQUAL model and adding other factors related to restaurant and the general characteristics of the families. The data were analyzed using SPSS 10.0 WIN program for descriptive analysis, a chi-square test and Pearson’s correlation test. The major results were as follows: From the factor analysis, the 35 items related to the quality of restaurant have been categorized into 10 factors, ie., ‘Health’, ‘Reliability’, ‘Employee’, ‘Food’, ‘Facilities’, ‘Product’, ‘Empathy’, ‘Access’, ‘Comfort’, and ‘Safety’. From the analysis of the correlation between family life cycle of four steps and 10 factors, four factors such as ‘Health’, ‘Facilities’ (p<0.001), ‘Comfort’ (p<0.01) and ‘Product’ (p<0.05) showed statistical significance. ‘Health’ and ‘Product’ factors marked the highest score in the family with senior couple live without children or single, but the lowest score in the family with young couple without children or single. ‘Facilities’ and ‘Comfort’ factors showed the highest scores in the family with under elementary school children, and the lowest scores in the family with over elementary school children.

• Korean Journal of Computational Design and Engineering
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• v.18 no.3
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• pp.177-188
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• 2013

The construction industry consists of various and massive architectural information as an architectural process includes a variety of design stages with cooperation of many disciplines. Particularly, architectural information is generated and managed through the life cycle of a building, from conceptual design stage to the construction and maintenance. A Building Information Model (BIM) serves as a shared knowledge resource for information about a facility forming a reliable basis for decisions during its life-cycle from inception onward. BIM technology accomplished quantitative development being utilized in various disciplines. However, it is necessary to develop environment and requirement for qualitative improvement of BIM based project. Particularly, requirement is very important for architectural design evaluations. The purpose of this study is to develop and apply of quality control check-list for improving the quality of architectural design in BIM environments. To achieve this purpose, the authors have investigated case study for open BIM data quality control (software, guideline and application case) and classified quality control targets according to physical/logical quality control and data quality. In addition, the authors have defined open BIM based quality control process and developed quality control check-list. Finally, the authors have developed automatic quality check system using requirements for efficient quality control based on open BIM.