• Earthquakes and Structures
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• v.4 no.3
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• pp.285-297
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• 2013

The effect of soil structure interaction (SSI) on seismic response of a multi-degree-of-freedom structure isolated with a friction pendulum system (FPS) is studied. In the analysis, the soil is considered as an elastic continuum and is modeled using the finite element method. The effect of SSI on response of the structure is evaluated for twenty far-field and twenty near-fault earthquake ground motions. The effect of friction coefficient of sliding material of FPS on SSI is also studied. The results of the study show that the seismic response of the structure increases for majority of the earthquake ground motions due to SSI. The sliding displacement and base shear are underestimated if SSI effects are ignored in the seismic analysis of structures isolated with FPS.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.10a
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• pp.137-146
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• 1999

The SSI(Soil-Structure Interaction) analyses are being performed for the KNGR(Korean Next Generation Reactor) design because the KNGR is developed as a standard nuclear power plant concept enveloping various soil conditions. the SASSI program which adopts the flexible volume method is used for the SSI analyses. The soil curves used in the three dimensional SSI analyses of KNGR Nuclear Island(NI) structures are based on the upper bound shear modulus curve and lower bound damping degradation on SSI response the average shear modulus curve with average damping curve was used for two soil cases. This study presents the results of the variances by using different soil nonlinearity parameters based on the paametric SSI analyses. The results include the maximum member forces(shear and axial force) at the base of the NI structures and the 5% damping Floor Response Spectra (FRS) at some representative locations at the top of the NI superstructures. They are also compared together with the enveloped SSI results for eight soil cases and fixed-base analysis for rock case by using two control motions.

• Earthquakes and Structures
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• v.24 no.3
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• pp.155-163
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• 2023

The purpose of this paper is to investigate the coupled effect of SSI and pounding on dynamic responses of unequal height adjacent buildings with insufficiently separation distance subjected to seismic loading. Numerical investigations were conducted to evaluate effect of the pounding coupling SSI on a Reinforced Concrete Frame Structure system constructed on different soil fields. Adjacent buildings with unequal height, including a 9-storey and a 3-storey reinforced concrete structure, were considered in numerical studies. Pounding force response, time-history and root-mean-square (RMS) of displacement and acceleration with different types of soil and separations were presented. The numerical results indicate that insufficient separation could lead to collisions and generate severe pounding force which could result in acceleration and displacement amplifications. SSI has significant influence of the seismic response of the structures, and higher pounding force were induced by floors with stiffer soil. SSI is reasonable neglected for a structure with a dense soil foundation, whereas SSI should be taken into consideration for dynamic analysis, especially for soft soil base.

• Journal of The Korean Association For Science Education
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• v.38 no.5
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• pp.739-751
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• 2018

The purpose of this study is to identify the differences of argumentation discourses for Socio-Scientific Issues in the types of decision-making and personality traits of pre-service biology teachers. For this study, SSI discussion topics were selected according to four types of decision making: logical reasoning, suggestion of complement, emotional base, and internal conflict. Three groups were constructed based on personality traits such as extroversion, acceptability, and integrity. Each three group used the workbook specially developed and freely used the smart device for discussion. A recorder and a camcorder were used to record each group, their behavior was recorded and the written materials during the discussion were collected for the results. Using Walton's analysis framework, the collected data analyzed in terms of the source of utterance, the process of dialogue shift, and the critical movements that can judge the reasoning of utterance. As a result of the study, it was confirmed that the decision-making type of SSI topics and learners' personalities were influential in the decision-making process of SSI small group discussions. This research shows that there is a need to develop instructional materials considering decision-making types and learners' personality types of students as well as pre-service teachers for SSI discussion.

• Journal of Korean Elementary Science Education
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• v.43 no.3
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• pp.446-459
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• 2024

This study aims to examine the development and learning process of the argumentative abilities in elementary school students with regards to learning science. Toward this end, the SSI argumentation education program was implemented in conjunction with the science curriculum for sixth-grade students across 10 months. In this process, the scoring criteria in terms of formal and content aspects were developed and used to assess their argumentative text analysis and expression abilities. The results were as follows: First, the type of SSI influenced their ability to analyze argumentative texts. However, their formal and content aspects improved as learning progressed. Second, with regards to the formal aspect associated with the ability to express argumentative texts, reasons were initially most frequently cited. Over time, incorporating evidence to support these reasons and the use of rebuttal also increased. Third, in terms of content aspect, the level of use of all elements increased as learning progressed; however, level of acknowledgments and rebuttal elements exhibited a relatively slower progress. In summary, ability of the students to analyze and express argumentative texts improved as they increasingly gained experience in learning about argumentation. The study deduced that elementary school students can develop their argumentative abilities through appropriate learning support, such as teacher feedback, along with implementation of the SSI argumentation education program over an extended period. Based on these results, the study proposes the development of SSI materials and incorporation of SSI argumentative writing in the science curriculum.

• Smart Structures and Systems
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• v.10 no.4_5
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• pp.331-351
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• 2012

In this study an output-only system identification technique for civil structures under ambient vibrations is carried out, mainly focused on using the Stochastic Subspace Identification (SSI) based algorithms. A newly developed signal processing technique, called Singular Spectrum Analysis (SSA), capable to smooth a noisy signal, is adopted for preprocessing the measurement data. An SSA-based SSI algorithm with the aim of finding accurate and true modal parameters is developed through stabilization diagram which is constructed by plotting the identified system poles with increasing the size of data matrix. First, comparative study between different approaches, with and without using SSA to pre-process the data, on determining the model order and selecting the true system poles is examined in this study through numerical simulation. Finally, application of the proposed system identification task to the real large scale structure: Canton Tower, a benchmark problem for structural health monitoring of high-rise slender structures, using SSA-based SSI algorithm is carried out to extract the dynamic characteristics of the tower from output-only measurements.

• Journal of the Korean Society of Earth Science Education
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• v.7 no.1
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• pp.11-23
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• 2014

The purpose of this study is to analyze the degree of argumentation structure development and factors of development of preservice teachers through SSI related argumentative writings. The study was conducted with 16 preservice teachers that students taking elementary science education theory class in K university located in Chungbuk. The testees wrote six SSI related argumentative writings (once a week), and we examined the degree of argumentation structure development and the change in the recognition of SSI of the preservice teachers by comparing the writings before and after the experiments. The experimental results showed that argumentation structure of the preservice teachers'writings improved and argument level (argument capability) of them also increased as the number of writing was increased. Factors that affect the argumentation structure improvement are mainly argumentation structure education, a number of writings, feedbacks, and subjects related to SSI. In this aspect, the argumentative writing on SSI has the effect of developing scientific sophistication and enhancing the decision-making power of students, and it has positive impacts in science education.

• Journal of the Earthquake Engineering Society of Korea
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• v.27 no.1
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• pp.25-35
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• 2023

Considering the non-linear behavior of structure and soil when evaluating a nuclear power plant's seismic safety under a beyond-design basis earthquake is essential. In order to obtain the nonlinear response of a nuclear power plant structure, a time-domain SSI analysis method that considers the nonlinearity of soil and structure and the nonlinear Soil-Structure Interaction (SSI) effect is necessary. The Boundary Reaction Method (BRM) is a time-domain SSI analysis method. The BRM can be applied effectively with a Perfectly Matched Layer (PML), which is an effective energy absorbing boundary condition. The BRM has a characteristic that the magnitude of the response in far-field soil increases as the boundary interface of the effective seismic load moves outward. In addition, the PML has poor absorption performance of low-frequency waves. For this reason, the accuracy of the low-frequency response may be degraded when analyzing the combination of the BRM and the PML. In this study, the accuracy of the analysis response was improved by adjusting the PML input parameters to improve this problem. The accuracy of the response was evaluated by using the analysis response using KIESSI-3D, a frequency domain SSI analysis program, as a reference solution. As a result of the analysis applying the optimal PML parameter, the average error rate of the acceleration response spectrum for 9 degrees of freedom of the structure was 3.40%, which was highly similar to the reference result. In addition, time-domain nonlinear SSI analysis was performed with the soil's nonlinearity to show this study's applicability. As a result of nonlinear SSI analysis, plastic deformation was concentrated in the soil around the foundation. The analysis results found that the analysis method combining BRM and PML can be effectively applied to the seismic response analysis of nuclear power plant structures.

• Journal of Korean Elementary Science Education
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• v.42 no.3
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• pp.421-433
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• 2023

This study examined the reasoning of gifted elementary science students in a socioscientific issues (SSI) classroom discussion on COVID-19-related trash disposal challenges. This study aimed to understand the characteristics of evidence use and decision-making difficulties in each type of SSI-related reasoning. To this end, the transcripts of 17 gifted students of elementary science discussing SSIs in a classroom were analyzed within the framework of informal reasoning. The analysis framework was categorized into three types according to the primary influence involved in reasoning: rational, emotional, and intuitive. The analysis showed that students exhibited four categories of evidence use in SSI reasoning. First, in the rational reasoning category, students deemed and recorded scientific knowledge, numbers, and statistics as objective evidence. However, students who experienced difficulty in investigating such scientific data were less likely to have factored them in subsequent decisions. Second, in the emotional reasoning category, students' solutions varied considerably depending on the perspective they empathized with and reasoned from. Differences in their views led to conflicting perspectives on SSIs and consequent disagreement. Third, in the intuitive reasoning category, students disagreed with the opinions of their peers but did not explain their positions precisely. Intuitive reasoning also created challenges as students avoided problem-solving in the discussion and did not critically examine their opinions. Fourth, a mixed category of reasoning emerged: intuition combined with rationality or emotion. When combined with emotion, intuitive reasoning was characterized by deep empathy arising from personal experience, and when combined with rationality, the result was only an impulsive reaction. These findings indicate that research on student understanding and faculty knowledge of SSIs discussed in classrooms should consider the difficulties in informal reasoning and decision-making.

• Journal of The Korean Association For Science Education
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• v.37 no.1
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• pp.181-192
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• 2017

This study aims to examine the educational effects of the SSI program using Digital Storytelling (DST) approaches. Since DST provides students opportunities to express their own opinions in the form of stories and to share learning outcomes through the web, we developed and implemented SSI program by adopting the concept of DST in order to produce synergistic effects on student learning. Twenty-four 9th graders who enthusiastically engaged in the DST-based SSI program participated in this study. The students responded to focus group interviews after the instruction, and all interviews were transcribed for analysis. The results indicated that the students became aware of socio-ethical perspectives of each SSI topic while searching and collecting data by themselves. They also felt the necessity to consider multiple perspectives around the issues by having discussions with group members. Second, pre-producing DST allowed students to negotiate to settle on a group discussion, and to use emotional contents that can lead viewers to have sympathy. In addition, while producing DST, students considered various factors such as design, soundtrack, visual effects, and screen composition in order to express their opinions and convey their messages more effectively. In the stage of sharing DST outcomes and receiving feedback, they realized new perspectives that they did not perceive in the previous production process, and to move them into an action for resolving the problems caused by SSI. This study showed the potentials of DST-based SSI instruction as a good strategy to support students' SSI engagement.