• Journal of Korean Elementary Science Education
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• v.42 no.1
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• pp.127-148
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• 2023

In this study, we used an analysis of the literature on socio-scientific issues (SSI) classes to examine domestic SSI class research and to determine the characteristics of SSI class research for each subject. A search for papers related to SSI classes published in Korea Citation Index-listed journals and candidate journals of the Korea Research Foundation found 95 relevant papers, which were then categorized according to participants and topics. Studies with both pre-service and experienced teachers attempted to investigate SSI-related perceptions. Studies of pre-service teachers tended to examine the level and development pattern of argumentation or to analyze decision-making characteristics and informal reasoning. Studies of experienced teachers tended to analyze instructional expertise in SSI teaching activities, focusing on teachers with substantial SSI teaching experience. Middle and high school students-related studies examined student decision-making and reasoning processes in SSI learning activities, developed SSI class programs, and analyzed educational effects. Examining the characteristics of SSI classes for elementary school students was difficult because few such studies have been published. However, the characteristics that elementary school students show in SSI learning situations could be inferred. A plan to revitalize SSI classes in the elementary science education field from the perspective of teacher education and class research is suggested.

• Journal of the Earthquake Engineering Society of Korea
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• v.19 no.1
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• pp.21-28
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• 2015

The nuclear accident due to the recent earthquake in Japan has triggered awareness of the importance of safety with regard to nuclear power plants (NPPs). An earthquake is one of the most important parameters which governs the safety of NPPs among external events. Application of a base isolation system for NPPs can reduce the risk for earthquakes. At present, a soil-structure interaction (SSI) analysis is essential in the seismic design of NPPs in consideration of the ground structure interaction. In the seismic analysis of the base-isolated NPP, it is restrictive to consider the nonlinear properties of seismic isolation devices due to the linear analysis of the SSI analysis programs, such as SASSI. Thus, in this study, SSI analyses are performed using an iterative approach considering the material nonlinearity of the isolators. By performing the SSI analysis using an iterative approach, the nonlinear properties of isolators can be considered. The difference between the SSI analysis results without iteration and SSI with iteration using SASSI is noticeable. The results of the SSI analysis using an effective linear (non-iterative) approach underestimate the spectral acceleration because the effective linear model cannot consider the nonlinear properties of isolators. The results of the SSI analysis show that the horizontal response of the base-isolated NPP is significantly reduced.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.6
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• pp.439-445
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• 2013

The soil-structure interaction(SSI) effect should be considered to accurately assess the seismic response of structure constructed on soft soil site other than the hard bedrock. Recently, the demand of SSI analysis has increased due to strengthening of the regulatory guidelines of nuclear power plant such as the USNRC SRP 3.7.2. In this study an accuracy and running time of the KIESSI-3D program for large-scale 3D SSI analysis were investigated. The seismic SSI analysis using the KIESSI-3D program was performed for several examples of large-scale three-dimensional soil-structure interaction system. The analysis results were compared with those of the ACS/SASSI program. Good agreements in transfer functions at selected locations showd that KIESSI-3D yields accurate solution for large-scale SSI problem. Moreover, it was found that running speed of the KIESSI-3D for large-scale 3D SSI analysis is much faster than that of the ACS/SASSI about 30~2000 times.

• Journal of Korean Neurosurgical Society
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• v.61 no.5
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• pp.645-652
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• 2018

Objective : This study aimed to investigate the rates, types, and risk factors of surgical site infection (SSI) following intracranial neurosurgical procedures evaluated by a Korean SSI surveillance system. Methods : This was a prospective observational study of patients who underwent neurosurgical procedures at 29 hospitals in South Korea from January 2017 to June 2017. The procedures included craniectomy, craniotomy, cranioplasty, burr hole, and ventriculoperitoneal shunt. Univariate and multivariate logistic regression analyses were performed. Results : Of the 1576 cases included, 30 showed infection, for an overall SSI rate of 1.9%. Organ/space infection was the most common, found in 21 out of the 30 cases (70%). Staphylococcus aureus was the most common (41%) of all bacteria, and Serratia marcescens (12%) was the most common among gram-negative bacteria. In univariate analyses, the p-values for age, preoperative hospital stay duration, and over T-hour were <0.2. In a multivariate analysis of these variables, only preoperative hospital stay was significantly associated with the incidence of SSI (p<0.001), whereas age and over T-hour showed a tendency to increase the risk of SSI (p=0.09 and 0.06). Conclusion : Surveillance systems play important roles in the accurate analysis of SSI. The incidence of SSI after neurosurgical procedures assessed by a national surveillance system was 1.9%. Future studies will provide clinically useful results for SSI when data are accumulated.

• Journal of the Korean Chemical Society
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• v.62 no.2
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• pp.137-147
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• 2018

The purpose of this study was to analysis total number of 123 SSI programs by SSI criteria. The criteria was consisted of subject, school level, starting point, scientific evidence, social content, use of scientific knowledge, level of conflict of interest, and evaluation and reflection. The results of the analysis are as follows. First, elementary school programs were the most and middle school programs were relatively few. Second, starting point was mainly in the actual situation, the fiction and nonfiction situation, and the situation including the controversy and conflict was less than 10%. Third, it was based on scientific evidence but mainly influenced by individual values and perceptions. Fourth, social contents were developed mainly in ethics/morality/value, political/social life/economy, environment contents. Fifth, the use of scientific knowledge mainly consisted of scientific decision making, scientific critical thinking, and information search. However, science inquiry, risk assessment, and cost effectiveness were less than 10%. Scientific inquiry is the essential factor of science education, and one of core competencies of national science curriculum. SSI program should be able to experience various kinds of conflicts, and to evaluate and reflect through reflection.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.6
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• pp.499-512
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• 2016

The boundary reaction method(BRM) is a substructure time domain method, it removes global iterations between frequency and time domain analyses commonly required in the hybrid approaches, so that it operates as a two-step uncoupled method. The BRM offers a two-step method as follows: (1) the calculation of boundary reaction forces in the frequency domain on an interface of linear and nonlinear regions, (2) solving the wave radiation problem subjected to the boundary reaction forces in the time domain. In the time domain analysis, the near-field soil is modeled to simulate the wave radiation problem. This paper evaluates the performance of the BRM according to modeling extent of near-field soil for the nonlinear SSI analysis of base-isolated NPP structure. For this purpose, parametric studies are performed using equivalent linear SSI problems. The accuracy of the BRM solution is evaluated by comparing the BRM solution with that of conventional SSI seismic technique. The numerical results show that the soil condition affects the modeling range of near-field soil for the BRM analysis as well as the size of the basemat. Finally, the BRM is applied for the nonlinear SSI analysis of a base-isolated NPP structure to demonstrate the accuracy and effectiveness of the method.

• Journal of Korean Neurosurgical Society
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• v.61 no.5
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• pp.608-617
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• 2018

Objective : This study aimed to investigate the rates, types, and risk factors of surgical site infection (SSI) following spinal surgery using data from a Korean SSI surveillance system that included diagnoses made by surgeons. Methods : This was a prospective observational study of patients who underwent spinal surgeries at 42 hospitals in South Korea from January 2017 to December 2017. The procedures included spinal fusion, laminectomy, discectomy, and corpectomy. Univariate and multivariate logistic regression analyses were performed. Results : Of the 3080 cases included, 30 showed infection, and the overall SSI rate was 1.0% (an incidence of 1.2% in spinal fusion and 0.6% in laminectomy). Deep incisional infections were the most common type of SSIs (46.7%). Gram-positive bacteria caused 80% of the infections, and coagulase-negative staphylococci, including Staphylococcus epidermidis, accounted for 58% of the gram-positive bacteria. A longer preoperative hospital stay was significantly associated with the incidence of SSI after both spinal fusion and laminectomy (p=0.013, p<0.001). A combined operation also was associated with SSI after laminectomy (p=0.032). Conclusion : An SSI surveillance system is important for the accurate analysis of SSI. The incidence of SSI after spinal surgery assessed by a national surveillance system was 1.0%. Additional data collection will be needed in future studies to analyze SSI in spinal surgery.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.337-344
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• 2006

This paper is concerned with the simplified criterion given in ASCE 4-98, for determining whether soil-structure interaction (SSI) analysis is required for seismic response analysis of nuclear power plant structures. In this study, the criterion is evaluated for a couple of example structures including an existing nuclear power plant and the Hualien large-scale seismic test building. Forced vibration analysis and seismic response analysis are carried out using the simple stick model with soil springs and an elaborated SSI analytical model. From the numerical analyses, it is found that the criterion may not allow the fixed-base analysis for bedrock with shear wave velocity of greater than 1,100m/s which is a well-known criterion for a rock site. In addition, it is indicated that peak amplification as well as the peak broadening specified in NRC RG 1.122. shall be considered to include the effects of SSI.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.6
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• pp.1-7
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• 2003

This paper presents a novel hybrid time-frequency-domain method for nonlinear soil-structure interaction(SSI) analysis. It employs, in a practical manner, a computer code for equivalent linear SSI analysis and a general-purpose nonlinear finite element program. The proposed method first (calculates dynamic responses on a truncated finite element boundary utilizing an equivalent linear SSI program in the frequency domain. Then, a general purpose nonlinear finite element program is employed to analyze the nonlinear SSI problem in the time domain, in which boundary conditions at the truncated boundary are imposed with the responses calculated in the previous frequency domain SSI analysis, In order to validate the proposed method, seismic response analyses are carried out for a 2-D underground subway station in a multi-layered half-space, For the analyses, a equivalent linear SSI code KIESSI-2D is coupled to ANSYS program. The numerical results indicate that the proposed methodology can be a viable solution for nonlinear SSI problems.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.5
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• pp.377-388
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• 2016

This study is aimed to evaluate the embedment effect of foundation as compared to the surface foundation on the response of a base-isolated nuclear power plant structure. For this purpose, the boundary reaction method (BRM), which is a two-step frequency domain and time domain technique, is used for the nonlinear SSI analysis considering nonlinear behavior of base isolators. The numerical model of the BRM is verified by comparing the numerical results obtained by the BRM and the conventional frequency-domain SSI analysis for an equivalent linear SSI system. Finally, the displacement response of the base isolation and the horizontal response of the structure obtained by the nonlinear SSI analysis using the moat foundation model are compared with those using the surface foundation model. The comparison showed that the displacement response of the base isolation can be reduced by considering the embedment effect of foundation.