• Structural Engineering and Mechanics
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• v.24 no.6
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• pp.709-725
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• 2006

In this paper the buckling and post-buckling behavior of slender bars under self-weight are studied. In order to study the post-buckling behavior of the bar, a geometrically exact formulation for the non-linear analysis of uni-directional structural elements is presented, considering arbitrary load distribution and boundary conditions. From this formulation one obtains a set of first-order coupled nonlinear equations which, together with the boundary conditions at the bar ends, form a two-point boundary value problem. This problem is solved by the simultaneous use of the Runge-Kutta integration scheme and the Newton-Raphson method. By virtue of a continuation algorithm, accurate solutions can be obtained for a variety of stability problems exhibiting either limit point or bifurcational-type buckling. Using this formulation, a detailed parametric analysis is conducted in order to study the buckling and post-buckling behavior of slender bars under self-weight, including the influence of boundary conditions on the stability and large deflection behavior of the bar. In order to evaluate the quality and accuracy of the results, an experimental analysis was conducted considering a clamped-free thin-walled metal bar. As this kind of structure presents a high index of slenderness, its answers could be affected by the introduction of conventional sensors. In this paper, an experimental methodology was developed, allowing the measurement of static or dynamic displacements without making contact with the structure, using digital image processing techniques. The proposed experimental procedure can be used to a wide class of problems involving large deflections and deformations. The experimental buckling and post-buckling behavior compared favorably with the theoretical and numerical results.

• Journal of Urban Science
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• v.11 no.2
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• pp.19-24
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• 2022

Conventional RC beams for crossing small and medium-sized rivers do not have a cross-sectional area, so the floating debris is accumulated and disasters such as damage to bridges occur. To improve this, the PSC method was invented. However, this also had problems such as transverse curvature, increase in dead weight due to cross-sectional shape, and negative moment generated during serialization, so it was necessary to develop a new type of girder. Therefore, it was intended to propose a LIT(Leton Interaction Thrust) girder bridge that is safer and has better performance than the conventional PSC girder with improved section efficiency. Unlike existing girder bridges, the LIT girder has the feature that the change in the strands of the entire girder occurs only in the vertical direction when the first tension is applied because the tendon arrangement is symmetrical by applying the raised portion. In addition, slab continuation generates a secondary moment that is advantageous to the continuous point, effectively controlling the negative moment and preventing the corrosion of the tendon. The dimensions of the cross section were determined, and the arrangement of the strands was designed to conduct structural analysis and detailed analysis. As a result of the structural analysis, the stress of the girder showed results within the allowable compressive stress, and the deflection showed the result within the allowable deflection. showed results. In addition, a detailed analysis was performed to examine the stress distribution around the girder body and the anchorage area and the stress distribution of the embossed portion, and as a result, the stress of the girder body due to the tension force showed a stable level.

• Journal of Korean Elementary Science Education
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• v.23 no.1
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• pp.1-7
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• 2004

The purpose of this study is to analyze elementary school students' personality, scientific attitude and to find the correlation between elementary school students' personality and scientific attitude. To determine this, the distribution of sixth graders' personality and scientific attitude was examined and correlation between the lower categories of each one was analyzed. The test tools and the subject were decided through the two preliminary examination, personality test and scientific attitude test were investigated appling to a total of 354 sixth-grade students at eight elementary schools in this study. The test results were analyzed with averages, standard deviations, correlations, ANOVA using SPSS/PC/sup +/. The major results of analysis are as follows. First, the distribution of scientific attitude proved that the average of boys' curiosity was higher than that of girls' curiosity, but girls' average was higher than boys' average in criticalness property, cooperation property, preparation property, continuation property and patience property. The distribution of upper group and lower group in personality properties revealed that the ratio of upper group was higher than that of lower group in activity property, social property, but the ratio of lower group was higher than that of upper group in responsibility and reflective property. Second, the socio-populational variables affecting 6th graders' personality' and science attitude were a sex, a sibling order. The cognition variables affecting 6th graders' personality and science attitude were preference, extent of usability to practical life and interest of science. Third, analyzing the correlation between lower categories of personality and lower categories of science attitude revealed that activity property of personality rather highly correlated to willingness property, critical property at .399(p<.01), .351(p<.01) respectively. and that consideration property of personality highly correlated to curiosity, critical property at .451 (p<.01), .415(p<.01) respectively.

• Journal of the Korean Society of Systems Engineering
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• v.20 no.1
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• pp.1-15
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• 2024

This study attempted to analyze whether the government's regulatory innovation efforts affect the continued operation of new products and new service-based businesses, such as regulatory compliance and response efforts, despite the perception of regulatory difficulties as business barriers for firms in new industries. Previous studies on the impact of regulations on companies in new industries were a limit to obtaining implications for regulatory issues and characteristics of each field due to the simplification of regulatory indicators and the establishment of field integration. To compensate for this, this study focused on the field of AI and DATA services, and subdivided regulatory issues to indicate practical inconvenience as variables, and model fit and hypothesis verification were performed by applying Structural Equation Model analysis based on the survey results of related companies. As a result, in the field of AI and DATA services, "Perceived regulatory irrationality" and "Perceived government regulatory innovation efforts" significantly affect the "Regulatory environment satisfaction" of the regulated, and "Perceived regulatory irrationality" and "Regulatory environment satisfaction" affect "Regulatory response efforts for companies in new industries to continue their businesses." The significance of this study is that it conducted research on the factors affecting the continuity of business of companies in the AI and DATA service sector by linking the analysis of the impact relationship between satisfaction and continuous use intention, which have been mainly used in the "Policy Acceptance Model" and "IT service sector," to "efforts for companies to continue their business in a new industrial regulatory environment." In addition, by presenting a new empirical model for new industry regulations, it is expected to be meaningful as it can provide a research foundation that can obtain practical implications in related fields.

• Journal of Engineering Education Research
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• v.7 no.3
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• pp.5-18
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• 2004

This paper, as a continuation of 'Job Analysis for developing Vocational Education & Training Program' executed from 1998, is aimed at complementing a guidebook for job analysis developed in 2002 to improve its usage in the areas of education, training and qualification, and at making and distributing basic data to develop curriculum for vocational education, standards for vocational training, and guidelines for making questions in qualification examination for 10 kinds of vocations through job analysis, which were precedently selected, for the purpose, out of environment industry-related vocations drawn from carried out together with this project by our Institute in 2003. The contents of this paper are first, to analyze what have precedently been done for job analysis, second, to complement a guidebook for job analysis, third, to select vocations for which job analysis will be made, and fourth, to carry out job analysis for developing curriculum for vocational education and training and guidelines for making questions and to distribute comprehensive data made on a basis of the results. Paper methods for the purpose of this paper are an analysis on literatures and data related to job analysis, experts councils for complementing job analysis, selecting target vocations and conducting job analysis by the vocations, and job analysis applying DACUM method. In the first place, this report presents job analysis models by procedures for developing curriculum for vocational education and training. The first step is preparation for job analysis, the second step the establishment of job models, the third step the drawn-out of knowledge, skills, and tools, the fourth step the selection of courses and subjects, the fifth step the specification of education and training contents, and the sixth the establishment of guidelines for making questions. In this paper, job analysis for 10 vocations were conducted in accordance with these procedures.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.6
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• pp.353-359
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• 2013

Purpose: Extensive research is actively ongoing for development of an ideal bone substitute that meets the gold standard. Tooth was selected as a donor site for evaluation of potentials in bone substitutes based on its similar chemical compositions to alveolar bone. Previous studies have evaluated inorganic components of autogenous tooth bone graft material (AutoBT) and osteoconductivity. In continuation from the previous studies, the current study was conducted for analysis of organic components and evaluation of osteoinductivity of AutoBT. Methods: Forty-six extracted teeth were collected from actual patients (Korea Tooth Bank, R&D Institute). Extracted teeth were processed into AutoBT and implanted in dorsal subcutaneous muscular tissues of 15 athymic mice. Biopsy samples were harvested at two, five, and eight weeks. The Bradford assay, sodium dodecyl sulphate polyacrylamide gradient gel, and western blotting were performed for investigation of organic contents of AutoBT. Results: Histology analyses showed signs of new bone formation as early as two weeks. Results of the Bradford assay indicated the existence of noncollagenous proteins (NCP). 0.29% (2.89 mg/g) of proteins were extracted by weight in the root portion of AutoBT; 0.02% (0.029 mg/g) and 1.79% (17.93 mg/g) of proteins were measured by weight in crown and block-form of AutoBT, respectively. However, recombinant human bone morphogenetic protein-2 was not observed in AutoBT. Conclusion: Within the limitation of the current study, AutoBT induced new bone formation by NCP embedded in dentin.

• Journal of Soil and Groundwater Environment
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• v.21 no.4
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• pp.30-41
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• 2016

The amount of groundwater related data is drastically increasing domestically from various sources since 2000. To justify the more expansive continuation of the data acquisition and to derive valuable implications from the data, continued employments of sophisticated and state-of-the-arts statistical tools in the analyses and predictions are important issue. In the present study, we employed a well established machine learning technique of Gaussian Process Regression (GPR) model in the trend analyses of groundwater level for the long-term change. The major benefit of GPR model is that the model provide not only the future predictions but also the associated uncertainty. In the study, the long-term predictions of groundwater level from the stations of National Groundwater Monitoring Network located within Han River Basin were exemplified as prediction cases based on the GPR model. In addition, a few types of groundwater change patterns were delineated (i.e., increasing, decreasing, and no trend) on the basis of the statistics acquired from GPR analyses. From the study, it was found that the majority of the monitoring stations has decreasing trend while small portion shows increasing or no trend. To further analyze the causes of the trend, the corresponding precipitation data were jointly analyzed by the same method (i.e., GPR). Based on the analyses, the major cause of decreasing trend of groundwater level is attributed to reduction of precipitation rate whereas a few of the stations show weak relationship between the pattern of groundwater level changes and precipitation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.2
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• pp.41-50
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• 2003

In this paper, nonlinear parallel structural analyses are introduced by using the parallel multifrontal solver and damage localization for 2D and 3D crack models is presented as the application of nonlinear parallel computation. The parallel algorithms related with nonliear reduce the amount of memory used is carried out because many variables should be utilized for this highly nonlinear damage analysis. Also, Riks' continuation method is parallelized to search the solution when strain softening occurs due to damage evolution. For damage localization problem, several computational models having up to around 1-million degree of freedoms are used. The parallel performance in this nonlinear parallel algorithm is shown through these examples and the local variation of damage at crack tip is compared among the models with different degree of freedoms.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.512-514
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• 2004

The Electro-Optical Camera (EOC) is a high spatial resolution, visible imaging sensor which collects visible image data of the earth's sunlit surface and is the primary payload on KOMPSAT-l. The purpose of the EOC payload is to provide high resolution visible imagery data to support cartography of the Korean Peninsula. The EOC is a push broom-scanned sensor which incorporates a single nadir looking telescope. At the nominal altitude of 685Km with the spacecraft in a nadir pointing attitude, the EOC collects data with a ground sample distance of approximately 6.6 meters and a swath width of around 17Km. The EOC is designed to operate with a duty cycle of up to 2 minutes (contiguous) per orbit over the mission lifetime of 3 years with the functions of programmable gain/offset. The EOC has no pointing mechanism of its own. EOC pointing is accomplished by right and left rolling of the spacecraft, as needed. Under nominal operating conditions, the spacecraft can be rolled to an angle in the range from +/- 15 to 30 degrees to support the collection of stereo data. In this paper, the status of EOC such as temperature, dark calibration, cover operation and thermal control is checked and analyzed by continuously monitored state of health (SOH) data and image data during the mission life of 3 years. The aliveness of EOC and operation continuation beyond mission life is confirmed by the results of the analysis.

• Journal of Industrial Convergence
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• v.22 no.3
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• pp.27-37
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• 2024

The purpose of this study was to analyze the impact of community characteristics of induced participants on values, attitudes, and behaviors (VAB) and intention to continue participation. Convenience sampling (n=192) was used to sample the research subjects, and confirmatory factor analysis, correlation analysis, and structural equation modeling were conducted using SPSS 26.0 and AMOS 26.0. The results of this study are as follows. 1) Among the community attributes of the participants, reputation, enjoyment, interaction, and social connection had a significant impact. 2) Value-Attitude-Behavior (VAB) was found to have a significant hierarchical impact. 3) Behavioral intention was found to have a significant effect on continuation intention. Through this, the Judo community needs to build a participant-centered organizational culture that can create positive value in order to increase participants' participation in Judo.