• Composites Research
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• v.31 no.5
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• pp.251-259
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• 2018

In this paper, statistical volume element modeling method was developed for multi-scale progressive failure analysis of fiber reinforced composite materials. Big-size statistical volume elements (BSVEs) was considered to minimize the size effect in the micro-scale, by including as many fibers as possible. For that purpose, a mesh cutting method is suggested and adapted into the fiber model generator that creates finite element domain rapidly. The fiber defect model was also developed based on the experimental distribution of the fiber strength. The size effects from the local load sharing (LLS) are evaluated by increasing the fiber inclusion in the micro-scale model. Finally, continuum damage mechanics (CDM) model to the fiber direction was extracted from numerical analysis on BSVEs. And it was compared with strength prediction from typical representative volume element (RVE) model.

• Korean Journal of Culture and Social Issue
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• v.13 no.3
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• pp.23-63
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• 2007

The purpose of this study is to develop and verify the Relational Self Scale(RSS). Based on the theoretical assumptions which relational self is multi-dimensional and constructed in social contexts, 10 categories with 102 items were yielded. In the process of content analysis, item analysis, exploratory factor analysis and correlation analysis by administering 102 items to korean adults, 31 items with 7 factors are extracted. The 7 factors are consisted of 'avoidance of relation', 'consciousness of others', 'agency', 'instrumental relation', 'empathy-care', 'perceived support from relation' and 'over-dependency to relation'. Next, Confirmatory factor analysis was conducted with 649 korean adults aged from 20's to 60's. The results of confirmatory factor analysis showed the RSS as a valid scale. The 7 factors of the RSS fitted well with men and women. The internal consistency of the RSS was proved to be acceptable. The latent mean analysis indicated that the relational self was not significantly different between men and women at 7 factors. Correlation analysis showed that the construct of relational self was significantly related to relational self-construal, self-esteem and attachment to parent and intimacy person. This study has implication in that relational self is defined and assessed as multi-dimensional construct, and that by administering RSS it is possible to evaluate distinctive korean people's relational self.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.5
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• pp.449-457
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• 2011

As automated image processing techniques have been required in multi-temporal/multi-sensor geospatial image applications, use of automated but highly invariant image matching technique has been a critical ingredient. Note that there is high possibility of geometric and spectral differences between multi-temporal/multi-sensor geospatial images due to differences in sensor, acquisition geometry, season, and weather, etc. Among many image matching techniques, the SIFT (Scale Invariant Feature Transform) is a popular method since it has been recognized to be very robust to diverse imaging conditions. Therefore, the SIFT has high potential for the geospatial image processing. This paper presents a performance test results of the SIFT on geospatial imagery by simulating various image differences such as shear, scale, rotation, intensity, noise, and spectral differences. Since a geospatial image application often requires a number of good matching points over the images, the number of matching points was analyzed with its matching positional accuracy. The test results show that the SIFT is highly invariant but could not overcome significant image differences. In addition, it guarantees no outlier-free matching such that it is highly recommended to use outlier removal techniques such as RANSAC (RANdom SAmple Consensus).

• Computers and Concrete
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• v.15 no.5
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• pp.735-758
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• 2015

This work deals with unilateral effect of quasi-brittle materials, such as concrete. For this propose, a two-dimensional meso-scale model is presented. The material is considered as a three-phase material consisting of interface zone, matrix and inclusions - each constituent modeled by an appropriate constitutive model. The Representative Volume Element (RVE) consists of inclusions idealized as circular shapes randomly placed into the specimen. The interface zone is modeled by means of cohesive contact finite elements developed here in order to capture the effects of phase debonding and interface crack closure/opening. As an initial approximation, the inclusion is modeled as linear elastic as well as the matrix. Our main goal here is to show a computational homogenization-based approach as an alternative to complex macroscopic constitutive models for the mechanical behavior of the quasi-brittle materials using a finite element procedure within a purely kinematical multi-scale framework. A set of numerical examples, involving the microcracking processes, is provided. It illustrates the performance of the proposed model. In summary, the proposed homogenization-based model is found to be a suitable tool for the identification of macroscopic mechanical behavior of quasi-brittle materials dealing with unilateral effect.

• Journal of Korean Academy of Nursing
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• v.43 no.3
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• pp.379-388
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• 2013

Purpose: The purpose of this study was to develop a tool to evaluate patient safety culture in nursing homes and to test its validity and reliability. Methods: A preliminary tool was developed through interviews with focus group, content validity tests, and a pilot study. A nationwide survey was conducted from February to April, 2011, using self-report questionnaires. Participants were 982 employees in nursing homes. Data were analyzed using Cronbach's alpha, item analysis, factor analysis, and multitrait/multi-Item analysis. Results: From the results of the analysis, 27 final items were selected from 49 items on the preliminary tool. Items with low correlation with total scale were excluded. The 4 factors sorted by factor analysis contributed 63.4% of the variance in the total scale. The factors were labeled as leadership, organizational system, working attitude, management practice. Cronbach's alpha for internal consistency was .95 and the range for the 4 factors was from .86 to .93. Conclusion: The results of this study indicate that the Korean Patient Safety Culture Scale has reliability and validity and is suitable for evaluation of patient safety culture in Korean nursing homes.

• Journal of The Korean Association of Information Education
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• v.15 no.3
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• pp.355-363
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• 2011

Level-Based Education is necessary for the multi-cultural learners because they tend to have the academic underachievement and learning deficiency that cause the huge educational gap. However, it is very hard to make the best of competence for the multi-cultural learners in the classroom. So, it is needed to suggest how we can use the educational contents that are appropriate for the Level-Based Learning and Individual Learning to make good use of teaching the learners from multi-cultural families. However, developing the new educational contents takes much time and cost, we have to improve existing contents for the student from multi-cultural families to use it. Hence, the purpose of this thesis is to develop the educational appropriateness evaluation scale to verify the educational contents that are for the multi-cultural students based on the educational content's evaluation tool, so by developing the scale, I intend to evaluate the 4~6 grades' Korean contents of the E-learning service and provide the ways of improvement.

• Journal of The Korean Society of Integrative Medicine
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• v.11 no.3
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• pp.35-47
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• 2023

Purpose : As the population aging deepens, the number of elderly people with arthritis is also continuously increasing. Accordingly, this study intended to identify the factors influencing the health-related quality of life (HINT-8) of the elderly with arthritis according to household type and provide baseline data for developing a measure to enhance the life quality of the elderly with arthritis. Methods : The factors influencing the health-related quality of life (HINT-8) of the elderly with arthritis were identified based on the raw data from the Korea national health and nutrition examination survey conducted in 2021. Data were analyzed with SPSS Statistics ver 25.0 for windows (IBM Corp), and the significance level (α) was set to .05. Statistical analysis was performed with t-test, ANOVA, multiple regression analysis, and post-hoc analysis with Duncan test. Results : The factors that influenced the health-related quality of life (HINT-8) of single-households were medical aid (β=-.17, p=.045), restriction of activity (β=-.17, p=.023), self-rated health status (β=.29, p<.001), and anxiety scale (β=-.36, p<.001). The factors that influenced the health-related quality of life (HINT-8) of multi-households were an age of 75 or over (β=-.14, p=.011), living in rural (β=-.14, p=.003), the outpatient department treatment experience (β=-.09, p=.047), self-rated health status (β=.26, p<.001), anxiety scale (β=-.29, p<.001), and stress (β=-.22, p<.001). Conclusion : Factors affecting the health-related quality of life (HINT-8) of the elderly with arthritis were found to be different between single-person households and multi-person household. Therefore, it is necessary to prepare measures to improve the quality of life of the elderly with arthritis by considering the factors influencing the health-related quality of life (HINT-8) of the elderly with arthritis according to the household type identified in this study.

• Composites Research
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• v.36 no.4
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• pp.253-258
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• 2023

Although the development of transportation means has realized the right to mobility for the disabled who have difficulty in moving, it can be said that the improvement of the safety of passengers with disabilities that can occur in a car accident is lower than that of ordinary passenger seats. In particular, in the case of a rear-end collision that can occur suddenly, it is a reality that disabled passengers are vulnerable to head and neck injuries. Therefore, in this study, a multi-layer headrest foam that divides the headrest into three parts in the coronal plane was proposed to improve the head and neck injury index of disabled passengers in the vehicle in the event of a rear-end collision of a wheelchair transport vehicle. A range of stress scale factors was selected to give various compressive characteristics of the foam through low-speed rear-end collision analysis through a simple model, and GA optimization was performed by specifying the range as a parameter. Through the optimization result, the phase relationship between HIC and NIC was analyzed according to the compression characteristics of the layers. HIC responded most sensitively to the compression characteristics of the front layer and NIC responded to the compression characteristics of the mid layer, and the compression characteristics of the rear layer showed the lowest. A normal headrest and an optimized multi-layer headrest were placed in the validation model to analyze the low-speed rear-end collision sled test, and HIC and NIC were derived lower in the multi-layer headrest than in the general headrest. The compression behavior of the multi-layer headrest was also clearly shown, and it was verified that the multi-layer headrest was effective in improving the injury index of the head and neck compared to the general headrest.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.3
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• pp.138-147
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• 2017

As the functions and structure of the system are complicated and elaborated, various types of structures are emerging to increase reliability in order to cope with a system requiring higher reliability. Among these, standby systems with standby components for each major component are mainly used in aircraft or power plants requiring high reliability. In this study, we consider a standby system with a multi-functional standby component in which one standby component simultaneously performs the functions of several major components. The structure of a parallel system with multifunctional standby components can also be seen in real aircraft hydraulic pump systems and is very efficient in terms of weight, space, and cost as compared to a basic standby system. All components of the system have complete operation, complete failure, only two states, and the system has multiple states depending on the state of the component. At this time, the multi-functional standby component is assumed to be in a non-operating standby state (Cold Standby) when the main component fails. In addition, the failure rate of each part follows the Weibull distribution which can be expressed as increasing type, constant type, and decreasing type according to the shape parameter. If the Weibull distribution is used, it can be applied to various environments in a realistic manner compared to the exponential distribution that can be reflected only when the failure rate is constant. In this paper, Markov chain analysis method is applied to evaluate the reliability of multi-functional multi-state standby system. In order to verify the validity of the reliability, a graph was generated by applying arbitrary shape parameters and scale parameter values through Excel. In order to analyze the effect of multi-functional multi-state standby system using Weibull distribution, we compared the reliability based on the most basic parallel system and the standby system.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1998.10a
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• pp.827-834
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• 1998

This paper describes a multi-level simulation technique and its implementation, which accurately solve voltages and currents of circuits descreibed at mixed levels of abstractions. A metho to form a tightly coupled simulation environment is proposed and, starting from a description of a circuit, simulation set-up and analysis procedure of the multi-level simulator for a transient response are presented. Circuit and behavioral simulation techniques and their implementations composing the multi-level simulation are explained in detail. Most of the algorithms implemented in the simulation are based upon the standard simulation techniques in order to obtain the reliability and accuracy of conventinoal simulators. Simulation examples show that the multi-level simulator can analyze circuits containing highly nonlinear behavioral models without loss of accuracy provided the behavioral models are accurate enough.