• Journal of the Korean earth science society
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• v.23 no.3
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• pp.207-220
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• 2002

The purpose of this study was to verify the trends of Korean students' achievement of earth science, especially the gender differences, in recent two international comparative studies, TIMSS-R (The Third International Mathematics and Science Study-Repeat) and PISA 2000 (Programme for International Student Assessment). To achieve this purpose, the 33 earth science items in TIMSS-R and 13 earth and environmental science items in PISA 2000 were analyzed. As a result of the comparison between Korean- and international percent correct, Korean students showed especially higher achievement in close-ended items or items required 'understanding of simple information.' Korean students, in particular Korean male students, also showed higher achievement in items of data interpretation. On the other hand, Korean students, in particular Korean female students, showed relatively lower achievement in astronomy items. The serious gender differences occurred in all aspects of items, regardless of item content, item format, and performance expectations.

• Journal of The Korean Association of Information Education
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• v.20 no.2
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• pp.179-188
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• 2016

This study is to analyze how is the gifted in Informatics student's cognitive features different from others and present standard for screening. So ultimately, I hope this study contribute to the promising perspective and curriculum development for gifted elementary school students in information science. And hopefully give an Implications for the way forward as an information special education by study of problem solving skills that underlie the learning ability. These skills are being able to collect, analyze, synthesize and apply the informations so that make sustainable development possible. Therefor, the ultimate goal of this study is to provide better education for the gifted in Informatics student's basic learning skills.

• Journal of Educational Research in Mathematics
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• v.26 no.3
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• pp.527-542
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• 2016

In the mathematics curriculum that was revised in 2009, statistical literacy is explicitly addressed as a goal and specific objectives are included. However, statistical literacy has not been addressed in the studies on KSAT. This study aimed to draw implications on how to improve KSAT in a sense that statistical literacy could be evaluated instead of testing typical facts or skills by comparing KSAT with SAT. We used mathematical problem solving process and category of context of PISA framework (OECD, 2013) to administer the comparison of KSAT and SAT. Result shows that both KSAT and SAT use various context, but items in KSAT is limited in assessing critical understanding. We suggested several ways to develop context-based items for KSAT in which statistical literacy could be assessed.

• Earthquakes and Structures
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• v.18 no.1
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• pp.129-145
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• 2020

Seismic resilience is a key feature for buildings that play a strategic role within the community. In this framework, not only the structural and non-structural elements damage but also the protracted structural dysfunction can contribute significantly to overall seismic damage and post-seismic crisis situations. Reduction of the residual and peak displacements and energy dissipation by replaceable elements are some effective aspects to pursue in order to enhance the resilience. Control systems able to adapt their response based on the nature of events, such as active or semi-active, can achieve the best results, but also require higher costs and their complexity jeopardizes their reliability; on the other hand, a passive control system is not able to adapt but its functioning is more reliable and characterized by lower costs. In this study it is proposed a strategy for the optimization of the dissipative capacity of a seismic resistant system obtained placing in parallel two different groups dissipative Re-Centering Devices, specifically designed to enhance the energy dissipation, one for the low and the other for the high intensity earthquakes. In this way the efficiency of the system in dissipating the seismic energy is kept less sensitive to the seismic intensity compared to the case of only one group of dissipative devices.

• Nuclear Engineering and Technology
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• v.44 no.6
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• pp.611-622
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• 2012

"Scaling" plays an important role for safety analyses in the licensing of water cooled nuclear power reactors. Accident analyses, a sub set of safety analyses, is mostly based on nuclear reactor system thermal hydraulics, and therefore based on an adequate experimental data base, and in recent licensing applications, on best estimate computer code calculations. In the field of nuclear reactor technology, only a small set of the needed experiments can be executed at a nuclear power plant; the major part of experiments, either because of economics or because of safety concerns, has to be executed at reduced scale facilities. How to address the scaling issue has been the subject of numerous investigations in the past few decades (a lot of work has been performed in the 80thies and 90thies of the last century), and is still the focus of many scientific studies. The present paper proposes a "roadmap" to scaling. Key elements are the "scaling-pyramid", related "scaling bridges" and a logical path across scaling achievements (which constitute the "scaling puzzle"). The objective is addressing the scaling issue when demonstrating the applicability of the system codes, the "key-to-scaling", in the licensing process of a nuclear power plant. The proposed "road map to scaling" aims at solving the "scaling puzzle", by introducing a unified approach to the problem.

• Wind and Structures
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• v.1 no.1
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• pp.1-23
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• 1998

This paper describes wind investigations for the Leaning Tower of Pisa which were conducted as part of an overall evaluation of its behaviour. Normally a short, stiff and heavy building would not be a candidate for detailed wind analyses. However, because of extremely high soil pressures developed from its inclination, there has been increasing concern that environmental loading such as wind actions could combine with existing conditions to cause the collapse of the tower. The studies involved wind assessment at the site as a function of wind direction, analysis of historical wind data to determine extreme wind probabilities of occurrence, estimation of structural properties, analytical and boundary layer wind tunnel investigations of wind loads and evaluation of the response with special concern for loads in the direction of inclination of the tower and significant wake effects from the neighboring cathedral for critical wind directions. The conclusions discuss the role of wind on structural safety, the precision of results attained and possible future studies involving field measurements aimed at validating or improving the analytical and boundary layer wind tunnel based assessments.

• Research in Mathematical Education
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• v.26 no.3
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• pp.235-252
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• 2023

We investigated the classification of learner groups for students' mathematical modeling competency and analyzed the characteristics in each profile group for each country and variable using PISA 2012 data from six countries. With a perspective on measuring sub-competency, we applied the latent profile analysis method to student achievement for mathematical modeling variables - Formulate, Employ, Interpret. The findings showed the presence of 4-6 profile groups, with the variables exhibiting high and low achievement within each profile group varying by country, and a hierarchical structure was observed in the profile group distribution in all countries, interestingly, the Formulate variable showed the largest difference between high-achieving and low-achieving profile groups. These results have significant implications. Comparison by country, variable, and profile group can provide valuable insights into understanding the various characteristics of students' mathematical modeling competency. The Formulate variable could serve as the most suitable predictor of a student's profile group and the score range of other variables. We suggest further studies to gain more detailed insights into mathematical modeling competency with different cultural contexts.

• Coupled systems mechanics
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• v.12 no.5
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• pp.429-444
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• 2023

The comprehension and structural modeling of masonry constructions is fundamental to safeguard the integrity of built cultural assets and intervene through adequate actions, especially in earthquake-prone regions. Despite the availability of several modeling strategies and modern computing power, modeling masonry remains a great challenge because of still demanding computational efforts, constraints in performing destructive or semi-destructive in-situ tests, and material uncertainties. This paper investigates the shear behavior of masonry walls by applying a plane-stress FE continuum model with the Modified Masonry-like Material (MMLM). Epistemic uncertainty affecting input parameters of the MMLM is considered in a probabilistic framework. After appointing a suitable probability density function to input quantities according to prior engineering knowledge, uncertainties are propagated to outputs relying on gPCE-based surrogate models to considerably speed up the forward problem-solving. The sensitivity of the response to input parameters is evaluated through the computation of Sobol' indices pointing out the parameters more worthy to be further investigated, when dealing with the seismic assessment of masonry buildings. Finally, masonry mechanical properties are calibrated in a probabilistic setting with the Bayesian approach to the inverse problem based on the available measurements obtained from the experimental load-displacement curves provided by shear compression in-situ tests.

• Journal of the Korean Society of Visualization
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• v.22 no.1
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• pp.40-48
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• 2024

This study presents an in-vitro model designed to simulate mitral valve regurgitation, aiming to compare the quantification results between Proximal Isovelocity Surface Area(PISA) and 4D Flow MRI on both fixed and valve annulus tracking(VAT) views. The in-vitro model replicates the dynamic conditions of the mitral valve in a pulsatile environment, utilizing a piston pump set at 60 bpm. Through systematic experiments and analysis, the study evaluates the accuracy and effectiveness of PISA and 4D Flow MRI in assessing regurgitation severity, considering both fixed and valve annulus tracking. The displacement length measured in echo closely resembled that of optical measurements, making it advantageous for structural analysis. VAT-4D flow MRI exhibited the smallest deviation from actual flow rate values, establishing it as most accurate method for quantitative regurgitation assessment.

• Communications of Mathematical Education
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• v.28 no.2
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• pp.235-253
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• 2014

This study aims to develop strategies for improving the affective characteristics of Korean students based on results from international achievement tests. In pursuing the goal, different research methods are employed including a) analysis of the theories and literature regarding the affective domains included in PISA and TIMSS studies; b) analysis of the current situation and needs of Korean students with respect to the affective factors based on PISA and TIMSS results; c) case studies of best practices in relation to students' affective domains in Korea and abroad; and d) development of strategies for improving and supporting Korean students' affective characteristics. Especially, this paper deals with the analysis of the results from in-depth interviews and class observations, so as to identify the current situation and best practice cases of students' affective characteristics education in Korea. The results are classified into a) curriculum, which is in turn divided into national curriculum and reconstruction of curriculum school and classroom; and b) teaching, learning and evaluation, which is in turn divided into learner characteristics, motivation, teaching strategies, class grouping, activities and interaction, question and feedback, evaluation methods, and evaluation tools. Support plans in terms of school and social environments are also suggested based on the results.