• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.10
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• pp.25-33
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• 2015

LED lightings combined with IT technology can provide variable illumination environments that can be controlled by users according to their emotional need and preferences. This is one of the most beneficial functions compared with conventional lightings offering only fixed color and brightness. There is however lack of analysis data for creating practical lighting solutions satisfying user preferences in a wide range of applications from residential to commercial places. To materialize the technical advantages of user-controllable LED lightings, more observation data are required in various situations. Therefore, dissimilar emotional needs are determined in the present study for compartmental office spaces (staff lounge room, meeting room and desk job place) through subjective experiments by 45 observers. The optimum lighting conditions (CCT and illuminance) are finally obtained using Response Surface Method and relevant prediction functions are also deduced. The final outcome can be applied for making user-preferred office illumination products.

• The Mathematical Education
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• v.49 no.4
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• pp.501-522
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• 2010

In this study, 'Instruments of the achievement attribution in mathematical learning' was develop to investigate the reasons of mathematical learning achievement by reflecting Korean middle school and high school students' psychological characters and learning context in mathematical learning. To develop the appropriate items for the achievement attribution in mathematical learning, after reviewing attribution literature thoroughly, first version of the instrument was developed and Exploratory Factor Analysis and Confirmatory Factor Analysis were conducted. Then, to reduce the effect of the gender difference and achievement level difference, Differential Item Functioning was performed. Also, using Multiple group Confirmatory Factor Analysis, this instrument was investigated to see whether this can be used for both middle school and high school. The final items for success attribution are 3 items for luck, 3 items for effort, 2 items for ability. The failure attribution were composed of 3 items for luck, 3 items for effort, 2 items for ability, and 2 items for other. The instrument was developed by using large samples and psychometric analysis. Therefore, mathematic teachers can use this instrument efficiently to make a foundation for better learning environment so students' cognitive area and affective area can be harmonized.

• The Korean Journal of Food And Nutrition
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• v.30 no.5
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• pp.1087-1095
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• 2017

We examined the quality characteristics of pound cake with prepared Aronia melanocarpa powder, which included the physical characteristics, antioxidant activity and sensory evaluation in this study. Pound cakes were prepared with various ratios of Aronia powder (0, 5, 10, 15, 20%). No significant difference in loss rate or weight was found from increased Aronia powder concentration. The color of pound cake was darker and reddish with the addition of Aronia powder. Lightness (L) and yellowness (b) significantly decreased with the addition of Aronia powder, whereas redness (a) increased (p<0.05). the qualities of hardness, cohesiveness, gumminess and chewiness of the pound cake prepared with the addition of Aronia powder were significantly increased when compared to control(p<0.05), with exception of 20% addtion. Total phenolic contents and DPPH radical scavenging activity was significantly elevated by the addition of Aronia powder(p<0.05). The pound cake with 10% Aronia powder showed the strongest positive sensory properties with regard to taste and overall palatibility. These results suggest that the addition of 10 % Aronia to pound cake batter could well serve to improve the overall quality, texture and taste of the final product.

• Journal of Surface Science and Engineering
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• v.54 no.6
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• pp.371-379
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• 2021

The use of anti-corrosive oil (AC) is inevitable for production of industrial steels to prevent corrosion. The AC is degreased before application of steels, which crucially effects on final products, such as automobile, electricity etc. However, qualitative/quantitative evaluation of degreasing performance are steal insufficient. In this study, degreasing performance of anti-corrosive oil on steel have been studied through X-ray photon spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). Commercial automotive steels (AMS) are coated with 4 different anti-corrosive oils (namely AC1-AC4). In XPS, intensity of C1s peak remained after degreasing indirectly indicates incomplete degreasing. Thus, higher C1s peak intensity means less effective degreasing by degreasing agent. peak intensity of C1s peak shows opposite tendency of peak intensity of O1s. We found that EIS analysis is not applicable to mild steel (such as AMS1) due to corrosion during measurement. However, alloy steel can be fully analyzed by EIS and XPS depth profile.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.4
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• pp.213-219
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• 2018

Mechanical components are to be produced with accurate dimensions in order to function properly in assemblies of a machine. Once designs of mechanical components are created, designers examine the designs by adopting many known experimental methods. A primary test method includes stress and strain evaluation of structural parts. In addition, fatigue test and vibration analysis are an important test method for mechanical components. Real experiments at a laboratory are established when products are manufactured. Since design changes should be done before producing the designs in factories, rapid modifications for new designs are required in production industries. FEM simulation is a proper choice for a design evaluation with speed at a detail stage in design process. This research focuses modeling and mechanical simulation of a mechanical component in order to ensure structural safety. In this paper, a universal joint, being used in driving axels of vehicles, is studied as a target component. A design model is created and tested in some ways by using commercial software of FEM. The designed component is being twisted to transmit heavy power and thus, torsional stress should be under strengths of the component's material. The next is fatigue analysis to convince fatigue cycles to be within the endurance limit of the material. Another test is a vibration analysis for rotational components. This research draws final conclusions from these test analyses and recommends whether the designed model is under safety condition in terms of mechanical structure.

• Korean Journal of Childcare and Education
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• v.14 no.6
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• pp.143-170
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• 2018

Objective: The purpose of this study was to develop assessment indicators and to verify the validity and reliability of the developed assessment indicators. Methods: A Delphi survey, focus group interviews, and content verification were conducted in order for experts to develop an evaluation index of the strengths of the day care center. A main survey was conducted on 438 daycare center principals and teachers to test their item quality, validity and reliability. Results: The final assessment indicators consisted of three areas, seven assessment criteria, 19 evaluation factors, 41 assessment items and a five-point rubric rating scale. As for the common strengths indicators, there were three assessment areas, five assessment criteria, 12 assessment elements and 22 assessment items. In regard to the selective strengths indicators, there were 3 assessment areas, 5 assessment criteria, 12 assessment elements and 16 assessment items. Conclusion/Implications: The efforts to confirm the strengths of daycare centers are expected to facilitate the identity building of the daycare center itself and for its organizational members to make a contribution to the qualitative improvement of childcare.

• Journal of Korea Game Society
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• v.19 no.2
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• pp.23-32
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• 2019

The popularization of VR content is slow. It's because they have not created a new visual experience, that is, 'utility' beyond 'interest'. The utility of VR content starts from functional reality. And to enhanced it, realistic interaction is required. Specifically, this study presents three methods of network play, character artificial intelligence, and Haptic implementation. In order to confirm the hypothesis, we conducted all phases of VR content production from baseball to contents production, play test, and technical verification. Through the test of the user and the evaluation institution about the final product, it was evaluated that it contributed to the realization of the content realism through the realistic visual effect, the play presentation, and the impact evaluation by the vibration.

• The korean journal of orthodontics
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• v.51 no.6
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• pp.397-406
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• 2021

Objective: The purpose of this study was to evaluate the effects of self-ligating brackets (SBs) and other factors that influence orthodontic treatment outcomes. Methods: This two-armed cohort study included consecutively treated patients in a private practice. The patients were asked to choose between SBs and conventional brackets (CBs); if any patient did not have a preference, he or she was randomly allocated to the CB or SB group. All patients were treated using an identical archwire sequence. Evaluated parameters were as follows: treatment duration, number of bracket failures, poor oral hygiene, poor elastic wear, extraction, use of orthodontic mini-implants (OMI), OMI failure, American Board of Orthodontics (ABO) Discrepancy Index (DI), arch length discrepancy, and ABO Cast-Radiograph Evaluation (CRE) score. Stepwise regression analysis was performed to generate the equation for prediction of the CRE. Results: The final sample comprised 134 patients with an average age of 22.73 years. The average DI, CRE, and treatment duration were 21.81, 14.25, and 28.63 months, respectively. Analysis of covariance showed a significant difference in CRE between the CB and SB groups after adjusting for the effects of confounding variables. Stepwise regression analysis using four variables, namely extraction, SB use, poor elastic wear, and additional appliance use, could explain only 25.2% of the variance in the CRE. Conclusions: Although the CRE was significantly better for CBs than for SBs, the clinical significance of this result seems to be limited. Extraction, SB use, poor elastic wear, and additional appliance use may have significant effects on treatment outcomes.

• Architectural research
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• v.22 no.4
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• pp.105-112
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• 2020

The purpose of this study is to establish a method for assessing a building's risk against disaster, tentatively named the Korean integrated disaster evaluation simulator (K-IDES). Based on previous studies, FEMA's risk management series and FEMA IRVS are selected as case studies for developing a frame work of K-IDES, through the comparative analysis of domestic building design guides, codes, and special acts related to disasters, in order to develop a risk assessment methodology for quantitative results. The assessment method consists of a classification system and calculating risk, and a simulation applying the developed checklist in K-IDES to similar types of high-rise buildings will be conducted to validate its accuracy. The final goal is to systemize an integrated risk management in a high-rise building against disasters for the purpose of recognizing vulnerable areas from the beginning of the design process and reinforcing it from potential threats after construction.

• Journal of Korean Academy of Nursing
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• v.50 no.6
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• pp.848-862
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• 2020

Purpose: The purpose of this study was to develop an instrument to evaluate the needs satisfaction of nurses and examine its validity and reliability. Methods: The initial items for the instrument were developed through a literature review and interviews, using the conceptual framework of Maslow's hierarchy of needs theory. The initial items were evaluated for content validity by 14 experts. Four hundred and eighty-six clinical nurses participated in this study through offline and online surveys to test the reliability and validity of the instrument. The first evaluation (n = 256) was used for item analysis and exploratory factor analysis, and the second evaluation (n = 230) was used to conduct a confirmatory factor analysis and to assess the criterion-related validity and internal consistency of the instrument. Test-retest reliability was analyzed using data from 30 nurses. Results: The final instrument consisted of 30 items with two sub-factors for five needs that were identified through the confirmatory factor analysis. The criterion-related validity was established using the five need satisfaction measures (r = .56). Cronbach's α for total items was .90, and test-retest reliability was .89. Conclusion: The findings from this study indicate that this instrument has sufficient validity and reliability. This instrument can be used for the development of nursing interventions to improve the needs satisfaction of clinical nurses.