In this study, we develop a sampling-based seismic probabilistic risk assessment (SPRA) quantification technique that can accurately consider a partially dependent condition of component seismic fragility information. Specifically, the SPRA quantification method is proposed by combining the advantages of two representative methodologies: EPRI seismic fragility and JAERI seismic fragility input-based quantification. The most important feature of the proposed method is that it performs a SPRA using a sampling technique by transforming the EPRI seismic fragility input into JAERI seismic fragility input. When the proposed sampling-based approach was applied to an example of simple system and to a SPRA problem of a nuclear power plant, it was observed that the proposed method yields approximately similar system seismic fragility and seismic risk results as those of the exact solution. Therefore, it is believed that the approach proposed in this study can be used as a useful tool for accurately assessing seismic risks, considering the partial seismic dependence among the components; the existing SPRA method cannot handle such partial dependencies.

As research evidence for the facilitative effects of reading strategies on reading comprehension has been accumulating, research and pedagogical interests in prereading strategies such as prediction and schema activation are increasing. Yet, little research evidence of how actual performance on such tasks may be related to reading comprehension is sparse. This study explores whether prediction abilities and content schema are related to Korean middle school EFL learners’ reading comprehension abilities in English, and whether such potential relations may differ for factual and inferential comprehension. The study participants were one hundred thirty-seven Korean seventh grade students, and their performance on schema activation, prediction, and reading comprehension abilities was investigated, while controlling for their overall language proficiency and literacy skills. The findings indicated that although both prediction abilities and content schema facilitated reading comprehension, prediction abilities were a relatively stronger predictor of both factual and inferential comprehension. The results further suggest the need to provide effective trainings on pre-reading strategies.

원자력발전소에는 전력생산과 안전과 관련된 수많은 기기들이 존재하고 있다. 기본적으로 원자력발전소의 구조물과 기기는 지진시 탄성거동올 목표로 안전율을 매우 높게 적용하여 설계해 왔다. 그러나 최근 발생한 지진의 규모가 증가함에 따라 설계수준을 초과한 지진에 대한 기기의 안전성을 재평가할 필요가 있다. 본 연구에서는 구조물의 비선형 거동에 의한 층응답을 분석하였고, 비선형해석에 의한 구조물의 비탄성구조응답계수를 재평가하였다. 기기의 지진취약도 평가시 구조물의 비탄성구조응답이 어떤 영향을 주는지 분석하기 위하여 재평가된 구조물의 비탄성구조응답계수와 기존에 사용되어온 구조물 비탄성구조응답계수를 적용하여 지진취약도 평가를 수행하였다. 해석결과에 따르면 비탄성구조응답계수는 기기의 고유진동수, 기기의 위치 그리고 구조물의 동특성에 따라 영향을 받는 것으로 나타났다.

면진장치는 지진력을 감소시키기 위하여 사용되어왔다. 원자력발전소에 면진장치가 적용된다면, 운영기간동안 구조물과 기기들은 동일한 내구성 및 성능이 확보되어야 한다. 본 연구에서는 면진된 원전의 지진에 대한 안전성을 확보하기 위하여 면진구조물의 장기거동을 해석적으로 분석하였다. 경년열화에 의한 면진장치 특성을 분석하였고, 다른 온도환경에서 면진장치의 경년열화에 의한 구조물의 지진응답을 분석하였다. 해석결과에 의하면 면진장치의 경년열화에 의하여 면진구조물의 고유진동수는 증가하였다. 그러나 면진 구조물의 최대가속도와 최대변위는 온도에 따라 크게 변하지 않았다. 면진장치의 열화에 의하여 구조물의 손상은 발생하지 않았지만 목표진동수 영역에서 스펙트럼가속도는 온도에 따라 증가하였다. 따라서 면진구조물에서 면진장치는 온도에 따른 지진응답의 증가를 고려하여 설치 및 제작해야 할 것으로 판단된다.

A methodology to evaluate the seismic performance of interface piping systems that cross the isolation interface in the seismically isolated nuclear power plant (NPP) was developed. The developed methodology was applied to the safety-related interface piping system to demonstrate the seismic performance of the target piping system. Not only the seismic performance for the design level earthquakes but also the performance for the beyond design level earthquakes were evaluated. Two artificial seismic ground input motions which were matched to the design response spectra and two historical earthquake ground motions were used for the seismic analysis of piping system. The preliminary performance evaluation results show that the excessive relative displacements can occur in the seismically isolated piping system. If the input ground motion contained relatively high energy in the low frequency region, we could find that the stress response of the piping system exceed the allowable stress level even though the intensity of the input ground motion is equal to the design level earthquake. The structural responses and seismic performances of piping system were varied sensitively with respect to the intensities and frequency contents of input ground motions. Therefore, for the application of isolation system to NPPs and the verification of the safety of piping system, the seismic performance of the piping system subjected to the earthquake at the target NPP site should be evaluated firstly.

면진장치는 상부구조물의 지진력을 감소시키는데 크게 기여하지만, 고감쇠고무 적층받침에 사용되는 고무재료는 시간이 경과함에 따라 열화되어 상부구조물의 동특성과 기기들의 지진응답에 영향을 줄 수 있다. 따라서 면진장치의 경년열화를 고려한 구조물의 지진응답을 분석하는 연구가 필요하다. 본 연구에서는 기존 문헌을 통하여 분석된 고무의 경년열화 특성을 사용하여 면진장치를 모델링하였다. 면진된 원전의 지진응답을 평가하기 위하여 격납건물과 보조건물을 대상 구조물로 선정하고, 진동수 성분이 다양한 입력지진동을 사용하여 구조물의 고유진동수, 최대지진응답, 층응답스펙트럼을 시간의 경과에 따라 분석하였다. 해석결과에 의하면 면진장치의 경년열화에 의하여 지진응답이 소폭 증가하였으며, 면진장치가 설치된 후 20년까지 지진응답의 증가율이 크게 나타나므로 이 기간에 상세한 검사가 시행되어야 할 것이다.

Various treatment modalities for vocal process granuloma include simple observation, antireflux therapy, voice therapy, botulinum injection, and steroid inhalation, but recurrence rates are high. Surgical excision can be considered in refractory and recurrent cases. In this study, the authors report the effectiveness of surgical excision using a carbon-dioxide laser with topical Mitomycin-C for the treatment of recurrent vocal process granuloma. The study included 28 patients with recurrent vocal process granuloma despite various treatments. The vocal process granuloma was excised using a carbon-dioxide laser and 1 cc of 0.4 mg/mL topical Mitomycin-C was applied for 4 minutes. Follow-up duration was 13-33 months (mean, 21.8 months). Of 28 patients, 19 (67.9%) were cured. Two who received surgical excision as a first-line treatment, 2 who used a steroid inhaler as a first-line treatment, and 5 who previously took antireflux medication as initial treatment showed recurrence. Surgical excision using a carbon-dioxide laser with topical application of Mitomycin-C is considered effective for recurrent vocal process granuloma.

This study is to evaluate the seismic demand of reinforced concrete structure considering the incident angle of the ground motions. For this purpose, a three-story structure is numerically analyzed under the three ground motion records through a multi-component incremental dynamic analysis (MIDA). The MIDA, an implementation of Incremental dynamic analysis, investigates two components of seismic excitation in which all accelerations are scaled to spectral accelerations at the fundamental natural periods of the buildings. The obtained results indicate the influence of the incident angle should be considered in the assessment response of structures. Maximum inter-story drift of structure will behave in the elastic or inelastic range depending on the variable incident angle