• The Journal of the Convergence on Culture Technology
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• v.5 no.4
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• pp.1-9
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• 2019

The purpose of this study was to examine the mediating effect of community child center service experience on the relationship between peer attachment and school adjustment. For the analysis, data from the 2nd Panel of Community Child Center(2017) were used. Frequency analysis, reliability analysis, correlation analysis, and multiple regression analysis were conducted using IBM SPSS Statistics 20 program. As a result, peer attachment(peer trust) has a positive effect on their center experience and school adjustment, and the center experience has a partial mediating effect on the relationship between peer attachment and school adjustment. The relationship with a center teacher and the center service evaluation of the children who use community child center are important factors that affect their school adjustment. Therefore measures should be taken to improve the quality of the community child center programs and its teachers.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.5
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• pp.379-388
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• 2019

Recently, a technique for acquiring spatial information data using UAV (Unmanned Aerial Vehicle) has been greatly developed. It is a very crucial issue of the GIS (Geographic Information System) mapping system that passes way point in the unmanned airframe and finally measures the accurate image and stable localization to the desired destination. Though positioning using DGPS (Differential Global Navigation System) or RTK-GPS (Real Time Kinematic-GPS) guarantee highly accurate, they are more expensive than the construction of a single positioning system using a single GPS. In the case of a low-priced single GPS system, the stability of the positioning data deteriorates. Therefore, it is necessary to supplement the uncertainty of the absolute position data of the UAV and to improve the accuracy of the current position data economically in the operating state of the UAV. The aim of this study was to present an algorithm enhancing the stability of position data in a single GPS mode of UAV with multiple GPS. First, the arrangement of multiple GPS receivers through the center of gravity of the UAV were examined. Next, MD (Mahalanobis Distance) is applied to detect instantaneous errors of GPS data in advance and eliminate outliers to increase the accuracy of previously collected multiple GPS data. Processing procedure for multiple GPS reception data by applying the center of the triangular method were presented to improve the position accuracy. Second, UAV navigation systems integrated multiple GPS through configuration of the UAV specifications were implemented. Using the unmanned airframe equipped with multiple GPS receivers, GPS data is measured with the TCM (Triangular Center Method). In addition, UAV equipped with multiple GPS were operated in study area and locational accuracy of multiple GPS of UAV with VRS (Virtual Reference Station) GNSS surveying were compared. The result showed that the error factors are compensated, and the error range are reduced, resulting in the reliability of the corrected value. In conclusion, the result in this paper is expected to realize high-precision position estimation at low cost in UAV using multiple low-cost GPS receivers.

• Journal of Energy Engineering
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• v.28 no.3
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• pp.10-17
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• 2019

According to South Korea's policy of supplying eco-friendly hydrogen vehicles, related industries are actively conducting research on the development of hydrogen cars and hydrogen charging station infrastructure. On the other hand, there is a lack of empirical research and assessment of the risk of non-metallic materials (such as liners, seals, gaskets) for classified materials that directly affect the durability and reliability of hydrogen vehicles and hydrogen charging stations. In this study, the risk factors for liners and seals of non-metallic parts used in high-pressure hydrogen installations were derived using FMEA, and the RPN values were calculated by converting the severity, frequency of occurrence and degree of detection into scores. The maximum value of the RPN 600, minimum value 63, average value 278.5 was calculated and periodic control of the liner and seal was identified as important. In addition, through hydrogen soakage and oxygen aging tests for non-metallic rubber products, physical test values that can be used as basic data were presented.

• Advances in aircraft and spacecraft science
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• v.3 no.1
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• pp.15-28
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• 2016

Although the aircraft industry was the first to use fibre composites, now they are increasingly used in a range of structural applications such as flooring, decking, platforms and roofs. Interlayer delamination is a major failure mode which threatens the reliability of composite structures. Delamination can grow in size under increasing loads with time and hence leads to severe loss of structural integrity and stiffness reduction. Delamination reduces the natural frequency and as a consequence may result in resonance. Hence, the study of the effects of delamination on the free vibration behaviour of multilayer composite structures is imperative. The focus of this paper is to develop a 3D FE model and investigate the free vibration behaviour of fibre composite multilayer sandwich panels with interlayer delaminations. A series of parametric studies are conducted to assess the influence of various parameters of concern, using a commercially available finite element package. Additionally, selected points in the delaminated region are connected appropriately to simulate bolting as a remedial measure to fasten the delamination region in the aim of reducing the effects of delamination. First order shear deformation theory based plate elements have been used to model each sandwich layer. The findings suggest that the delamination size and the end fixity of the plate are the most important factors responsible for stiffness reduction due to delamination damage in composite laminates. It is also revealed that bolting the delaminated region can significantly reduce the natural frequency variation due to delamination thereby improving the dynamic performance.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.4
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• pp.1-10
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• 2015

ISO 9001, quality management system, is widely known as advancing internal efficiency and productivity in various industry. As a result, the number of companies that have adopted ISO 9001's certification have been increasing continuously year by year since ISO 9000' family standard was published in 1987s. This fact shows that a lot of businesses are trying to get the accreditation for improving the competitiveness of quality. The purpose of this study is to present that ISO 9001's certification motives affect to the requirement's implementation and show that the execution of requirements influences on management performance in the small manufacturer. In order to carry out this research, we obtained 96 survey sheets and inspected twenty assumptions based on the reliability, validity of the questionnaires. The results of regression analysis are summarized as follows; First, the factors of certification motive influence on the requirement's implementation except resources management. Second, the two elements of ISO 9001 requirement, resources management and product realization, have an important effect on the operational performance and financial performance considerably in the companies that choose the internal motive. Finally, the two requisites of ISO 9001 requirement, resources management and measurement, analysis and improvement, affect to the operational performance and financial performance significantly in the businesses that select the external motive. Based on the results, the companies that choose the internal motive have a good performance to execute the ISO 9001 requirements. Also, to implement the requirements of ISO 9001 is helpful for the companies to produce the operational and financial performance.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.2
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• pp.127-134
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• 2016

This paper presents practical issues for test and evaluation(T&E) methods to develop defense systems. Our argument is motivated by several domestic defense cases and the cases lead us to discuss two main factors for reliable defense systems development: 1) statistical approaches and 2) technical schemes. Specifically, statistical approaches enable to provide credible interpretations about T&E results in the decision-making process. With practical T&E results of the “Red Shark” torpedo, we performed statistical hypothesis tests and suggest a minimum sample size to accept the hypothesis. Next, technical schemes have more direct effects on improving reliability of developed defense systems and we shortly introduce tools development for systems verification that is required to integrate several sub-systems, e.g., combat, sensor, weapon, and communication systems, within a defense system. We additionally summary some domain cases using modeling and simulation techniques for successful T&E. In closing, we expect that the paper shows empirical investigation and lessons learned with these two practical issues, which provides a guide those who desire to make decisions about reliable defense systems development.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.34 no.3
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• pp.183-188
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• 2008

Initial screening assay for depigmenting agents includes in vitro mushroom tyrosinase assay and antioxidant assay. Based on this screening result, melanin synthesis in melanocyte, in screened samples, is further measured. Measuring cellular melanin needs time, human resource, and skills. Therefore initial screening method should be reliable. We examined, 34 Chinese herbs, correlated the screening assay methods with cellular melanin. No reliable relationship was observed between factors, indicating the limitation in the use of these assays, probably due to the complexicity of melanogenesis.

• Smart Structures and Systems
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• v.19 no.1
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• pp.11-20
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• 2017

For structural damage detection of shear buildings, this paper proposes a new concept using structural element mass-stiffness vector (SEMV) based on special mass and stiffness distribution characteristics. A corresponding damage identification method is developed combining the SEMV with the cross-model cross-mode (CMCM) model updating algorithm. For a shear building, a model is assumed at the beginning based on the building's distribution characteristics. The model is updated into two models corresponding to the healthy and damaged conditions, respectively, using the CMCM method according to the modal parameters of actual structure identified from the measured acceleration signals. Subsequently, the structural SEMV for each condition can be calculated from the updated model using the corresponding stiffness and mass correction factors, and then is utilized to form a new feature vector in which each element is calculated by dividing one element of SEMV in health condition by the corresponding element of SEMV in damage condition. Thus this vector can be viewed as a damage detection feature for its ability to identify the mass or stiffness variation between the healthy and damaged conditions. Finally, a numerical simulation and the laboratory experimental data from a test-bed structure at the Los Alamos National Laboratory were analyzed to verify the effectiveness and reliability of the proposed method. Both simulated and experimental results show that the proposed approach is able to detect the presence of structural mass and stiffness variation and to quantify the level of such changes.

• Journal of The Korean Association For Science Education
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• v.41 no.6
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• pp.533-542
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• 2021

This study aims to develop an instrument for measuring high school students' action competence on climate change (ACoCC). The instrument is defined as the construct comprised of seven factors and thirty-five items and takes approximately 15 minutes to fill out. A panel of experts and students' content validation were undertaken to modify the items. Five hundred and twenty-eight first and second graders in Korean high schools participated in the instrument survey. To assess the reliability and validity of ACoCC instrument, item analysis (mean, skewness, kurtosis, item-total correlation), internal consistency estimate, and confirmatory factor analysis were used. It was appropriate to use the 7-dimensional ACoCC instrument (knowledge about climate change, climate change sensibility, reflection, communication, integrated thinking, willingness, decision making), with 35 items for high school students. The following instrument was self-report given in the 5-point Likert scale (1=strongly disagree, 2=disagree, 3=neutral, 4=agree, 5=strongly agree). The internal consistency coefficient was shown as a whole was shown as 0.953, and the subscale's internal consistency coefficient ranged from 0.786 to 0.862.

• Journal of Digital Convergence
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• v.19 no.12
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• pp.231-241
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• 2021

The consulting industry is also growing as the use of management consulting increases as the importance of management strategies for the survival of companies due to rapid environmental changes is highlighted. As a result, competition among consulting firms is intensifying, and securing competitiveness is essential. This study tried to confirm the method of securing competitiveness of consulting firms from the perspective of organizational competitiveness through organizational effectiveness. As the consulting service is a knowledge service field, an empirical analysis was conducted for consultants who performed it because professional human resources were a core technology. Exploratory factors, reliability analysis, and regression analysis were performed using SPSS 22.0. As a result of a study on the effect of consultants' organizational effectiveness on customer orientation, it was found that the consultant's organizational commitment and organizational performance had a significant effect. It was possible to confirm the importance of intrinsic motivation to secure the competitiveness of consulting firms in the changing environment. This presented practical implications for organizational management regarding the continuous growth of consulting firms.