Based on the nonlinear static analysis and the approximate seismic evaluation method adopted in “Guidelines for seismic performance evaluation for existing buildings, two methods to calculate strength demand for retrofitting individual structural walls in unreinforced masonry buildings are proposed.” The displacement coefficient method to determine displacement demand from nonlinear static analysis results is used for the inverse calculation of overall strength demand required to reduce the displacement demand to a target value meeting the performance objective of the unreinforced masonry building to retrofit. A preliminary seismic evaluation method to screen out vulnerable buildings, of which detailed evaluation is necessary, is utilized to calculate overall strength demand without structural analysis based on the difference between the seismic demand and capacity. A system modification factor is introduced to the preliminary seismic evaluation method to reduce the strength demand considering inelastic deformation. The overall strength demand is distributed to the structural walls to retrofit based on the wall stiffness, including the remaining walls or otherwise. Four detached residential houses are modeled and analyzed using the nonlinear static and preliminary evaluation procedures to examine the proposed method.
연층을 가지는 건축물들의 피해사례가 관측됨에 따라 기존 건축물 내진성능평가시 수직비정형의 고려가 중요해졌다. 하지만 기존 방법은 수직비정형을 충분히 반영하기 어렵기 때문에 수직비정형을 가지는 건축물에 대해 내진성능을 과소 혹은 과대평가할 여지가 있다. 본 연구는 강성기반 연층비(Soft Story Ratio, SSR)를 이용해 수직비정형 건축물의 내진성능평가 기법을 개발하는데 목적이 있다. SSR은 변위에 대한 요구량과 능력의 비율을 나타내고, 강성차이에 의한 수직비정형을 고려하여 건축물의 변위집중 비율을 의미하는 파라미터다. 1층 기둥을 변수로 하는 필로티 건축물 네 개를 대상으로 개발한 내진성능평가 기법을 기존의 내진성능평가 기법과 비교하였다. 기존 기법은 수직비정형이 극대화되는 모델에 대해 내진성능을 과대평가하는 경우가 발생하였다. 반면 제안된 기법은 모든 모델에 대해서 상세평가의 결과와 동일했다. 따라서 제안하는 내진성능평가 기법은 수직비정형이 극대화되는 필로티 건축물에서 기존의 방법보다 정밀하게 내진성능평가 결과를 제공할 수 있다고 사료된다.
Ground depression/cave-ins due to subsurface cavities have been occasionally occurred in urban area. To prevent the ground cave-ins, a ground penetrating radar (GPR) method was applied and more than 2,000 subsurface cavities were found in Seoul. For each cavity, excavation was carried out to investigate main cause of the cavity and then the site was restored permanently. It was found that this excavation-and-restoration method was not efficient to repair small size cavities. Instead, grouting methods was used to repair the small cavities temporarily. This study evaluated the field applicability of grouting methods on restoring small cavities. Three types of grouting materials were applied on 12 sections and two non-destructive tests were conducted in field. A falling weight deflectometer(FWD) test was conducted to assess the bearing capacity of the site before and after grouting. Ground penetrating radar (GPR) was used to evaluate the extent of the grouting materials to a cavity. From the FWD test results, the bearing capacity of the Section A and B was enhanced by 7.5% and 13.5% while the bearing capacity of the section C was reduced by 11.5%. It was found from the GPR tests that the grouting materials used in the Section B and C could fill the cavity well and also extended to surrounded area due to injection pressure or selfexpansion. In common, the small cavities could be restored quickly, less than 30 minutes per a cavity by the grouting methods. Hence it can be concluded that the grouting methods can be applicable to restore small cavities. However, it needs to consider the application of grouting methods carefully because the grouting methods can be lost through a pipe link to a cavity. Also, excavations can be conducted occasionally in urban roads so that the stiffness of grouting materials needs to soft enough to be excavated and strong enough to support traffic loads.
PURPOSES : The objective of this study is to evaluate the potential risk level of road cave-ins due to subsurface cavities based on the deflection basin measured with falling weight deflectometer (FWD) tests. METHODS: Ground penetrating radar (GPR) tests were conducted to detect road cavities. Then FWD tests were conducted on 13 pavement test sections with and without a cavity. FWD deflections and a deflection ratio was used to evaluate the effect of geometry of the cavity and pavement for road cave-in potentials. RESULTS: FWD deflection of cavity sections measured at 60 cm or a closer offset distance to a loading center were 50% greater than more robust sections. The average deflection ratio of the cavity sections to robust sections were 1.78 for high risk level cavities, 1.51 for medium risk level cavities, and 1.16 for low risk level cavities. The relative remaining service life of pavement with a cavity evaluated with an surface curvature index (SCI) was 8.1% for the high level, 21.8% for the medium level, and 89.8% compared to pavement without a cavity. CONCLUSIONS : FWD tests can be applied to detect a subsurface cavity by comparing FWD deflections with and without a cavity measured at 60 cm or a closer offset distance to loading center. In addition, the relative remaining service life of cavity sections based on the SCI can used to evaluate road cave-in potentials.
허베이 스피리트호의 유류유출량이 씨프린스호의 것에 비해 2.5배에 불과하지만, 그 경제적·환경적·사회적 피해는 30배에 이를 정도로 대규모 유류유출의 피해는 기하급수적으로 증가할 수 있다. 본 연구에서는 이와 같은 재난적 해양환경오염사고에 신속하고도 효율적으로 대응할 수 있는 다목적 대형방제선의 건조에 대한 기술적·경제적 타당성을 분석함으로써 다목적 대형방제선의 건조에 대한 당위성과 정당성을 확보하고자 한다. 다목적 대형방제선의 기술적 타당성분석과 선진해양국의 많은 사례를 검토한 결과, 4,000톤급의 자항식 호퍼준설선 겸용 방제선을 건조하는 것이 적합한 것으로 판단되었다. 경제적 타당성 분석결과, 가장 보수적인 추정의 B/C ratio는 0.82로 경제성에 미달하지만 자구적 노력을 통하여 경제성을 확보할 수 있다. 한편, 중간추정치와 낙관적 추정치의 B/C ratio는 각각 2.72와 5.82로 이 사업의 경제적 타당성을 충분히 확보할 수 있다.
본 연구의 목적은 무선 통신 사업자 간에 휴대폰에서 제공되는 휴대폰 벨소리 사운드의 음질차이가 있는지, 있다면 어느 요소에서 발생하는지를 조사하는 것이었다. 선두 무선 통신 사업자나 휴대폰 제조사가 가지는 브랜드의 영향 요소를 배재하고 음질의 차이가 생기는 요소들을 찾아내기 위한 일련의 실험이 계획되었다. 무선 통신 사업자, 휴대폰 제조사, 휴대폰 모델, 특정 장르, 음원 콘텐츠 제작자 등 음질의 차이가 발생 할 수 있는 요소들을 테스트 하였다. 연구결과 휴대폰을 통해 제공되는 벨소리 사운드는 무선 통신 사업자별로 음질 차이가 존재하는 것으로 조사되었다. 음질의 차이는 콘텐츠 및 휴대폰의 차이에서 발생하며, 동일휴대폰 모델의 경우에도 무선 통신 사업자 모델별로 음질의 차이가 발생하는 것을 알 수 있었다. 또한 콘텐츠를 제공하는 음원 제작사 별 음질의 차이도 있는 것으로 나타났다. 음악 장르에 대한 음질의 차이는 명확하게 나타나지 않았다. 제한된 샘플을 이용한 실험의 한계를 보완하기 위하여 휴대폰 제조업체의 사운드 전문가를 통한 인터뷰가 시행되었다. 인터뷰 결과 제품 가격의 차이에서 오는 스피커 단품 및 미디, 앰프 등 하드웨어적 차이가 음질에 영향을 끼치는 것으로 조사되었고, 부품 및 기구의 튜닝 또한 중요도를 갖는 것으로 조사되었다.
목적 : 본 연구는 한글 PEDI의 표준화를 위한 예비 연구로써 한글로 번역한 PEDI의 번역 정확도를 검증하고, 한글 PEDI로 국내 아동을 평가하여 동일 연령대의 미국 아동과의 기능수준을 비교하여 문화간 차이를 확인하기 위한 목적으로 실시하였다.
연구방법 : 한글 PEDI는 미국에서 대학교 이상의 교육을 받은 2개 국어 사용자 3명에게 의뢰하여 번역 정확도를 검증받았다. 미국아동과의 연령별 기능수준 비교는 어린이 집에 다니는 일반아동 28명을 2~5세까지 6개의 연령군으로 나누어 각 평가 결과를 비교하였다.
결과 : 번역 정확도의 검증 결과 기능적 기술 부분의 신변처리, 이동, 사회적 기능 영역과 보호자의 도움 및 조정/변경 부분에서 5점 만점에 평균 4.67이상으로 높게 나타났다. 또한 모두 4개 문항에서 2명 이상의 응답자가 번역 정확도가 나쁨이나 매우 나쁨에 응답하였다. 한국과 미국 아동들의 기능수준을 비교한 결과는 신변처리, 이동, 사회적 기능 영역과 보호자 도움 부분에서 아동들의 기능수준 차이가 나타났다. 규준 표준화 점수에서는 신변처리 영역의 2.5∼2.9세 연령군과 이동 영역의 2.0∼2.4, 2.5∼2.9, 3.0∼3.4세 연령군, 보호자 도움 부분의 2.5∼2.9세 연령군에서 한국 아동들이 미국아동들에 비해 낮은 기능수준을 보였다. 표준 점수에서는 이동 영역의 4.0∼4.4세 군, 사회적 기능 영역의 4.0∼4.4세 군과 보호자 도움 부분의 4.5∼4.9세 군에서 한국 아동들이 낮은 기능수준을 보였다.
결론 : 본 연구에서는 번역 정확도 검증 결과 4개 문항에 대한 수정이 이루어졌고, 한국과 미국 아동의 연령군에 따른 기능수준 비교에서 차이가 있는 것으로 나타났다.
본 연구의 목적은 정서의 경험과정 상에서 손상을 보이는 문제집단을 대상으로 하여 감성교육프로그램(EMTP)의 잠재적 적용가능성을 탐색하려는 것이다. 이를 위하여 본 연구에서는 12회기에 걸친 감성교육프로그램의 전후에 참가자들의 정서능력을 측정하고 감성교육프로그램의 실시에 따른 효과성을 검증하였다. 반복측정치를 위한 변량분석의 결과는 감성교육프로그램이 정서적 능력, 특히 자기동기화 및 타인의 감정관리 능력에 있어서는 유의한 향상을 이야기함을 확인시켜 주었다. 후속적으로 정서적 능력의 사전검사 점수를 토대로 우수, 문제집단을 선발하여 이들에게 감성교육프로그램이 서로 차별화된 반응을 야기하는지를 관찰하였다. 변량분석 결과, 잠재적 수형 인구와 유사한 특성을 지녔을 것이라 예상되었던 문제집단에게 있어서도 정서능력 우수집단에서 나타났던 긍정적인 프로그램 효과가 동일하게 산출된다는 것을 확인할 수 있었다. 이러한 사실들은 감성교육프로그램이 공감능력에 있어 현저한 손상을 안고 있는 수형집단에게도 유용하게 적용될 수 있을 것이란 기대를 갖게 한다. 국내에서는 정신병질자(psychopaths)의 범죄행위에 관련된 연구는 아직 일반화되어 있지 않음은 물론 그 중요성이 충분히 인지되어 있지 않고 있다. 또한 중범죄자 및 상습범죄자들의 재범을 억제할 수 있는 교정치료프로그램개발에 대한 충분한 연구가 미비한 실정이다. 이로 인해 최근 우리사회는 전술한 바와 같이 재범률이 지속적으로 증가하여 심각한 사회문제를 야기하고 있다. 그러므로 형사정책적 노력의 일환으로 재범률의 증가를 감소시키기 위한 중범죄자와 상습범죄자들의 원활한 사회복귀를 돕는 교정치료프로그램개발의 필요성은 우리나라 교정행정의 당면과제가 아닐 수 없다. 그러나 우리와는 달리 범죄학분야에서 선진국가들의 경우, 특히 북미지역에서는 범죄자들의 정신병질적 특성이 매우 중시되어 재범 예측의 가장 중요한 개인 내적인 변수로 다루어지고 있다.
The purpose of this study is to evaluate from English teachers' perspectives the secondary school English curriculum of the 7th National Curriculum, which became effective in 2001 for middle schools. With such a goal, the present study analyzes the results of questionnaires collected from middle school teachers of 7th-grade English. The study discusses the realities and problems of the 7th National Curriculum that teachers experience when they teach 7th-grade English classes. The study also discusses-solutions and alternatives proposed by teachers in order to contribute to the improvement of the English curriculum.
For the release of the nuclear power plant site after the decommissioning, a reliable exposure dose assessment considering the environmental impact of residual radionuclides is essentially required. In this study, the Derived Concentration Guideline Level (DCGL) for the hypothetically contaminated surface soil at the Wolsong nuclear power plant (NPP) unit 1 site was preliminarily calculated by using the RESRAD-OFFSITE computational code and compared with the other case studies. Moreover, radiation exposure dose for local residents and relevant exposure pathways were quantitatively analyzed based on the calculation model established through this work. For the target site modeling, the source term was determined by referring to the previous case studies regarding the nuclear power plant decommissioning, quantification analysis data of pressure tubes of Wolsong NPP unit 1, and radionuclide data estimated by using the MCNP/ORIGEN-2 code. In total, 14 different radioisotopes such as Ag-108m, C-14, Co-60, Cs-134/137, Fe-55, H-3, Nb-93m/94, Ni-63, Sb-125, Sn-121m, Sr-90, and Zr-93 were considered as target radionuclides. In addition, the geological structure model of the Wolsong NPP site was established based on the final safety analysis report of Wolsong NPP unit 1. The distribution coefficients (Kd) were taken from the JAEA-SDB to estimate the migration/retardation behavior of various radionuclides under the groundwater condition of the Wolsong NPP site. In the present work, the DCGL values were calculated according to the site release criterion of 0.1 mSv/yr, which indicates the radiation protection standard for the site release. Moreover, the exposure pathway and sensitivity analyses were conducted to assess the sensitive input parameters remarkably influencing the calculation result. For the evaluation of exposure dose for local residents, a site layout centered around Wolsong NPP unit 4, located in the closest proximity to the residents’ habitation area, was alternatively established and all potential exposure pathways were considered as a comprehensive resident farmer scenario. The results obtained from this study are expected to serve as a preliminary case study for the DCGL values regarding the surface soil at the Wolsong NPP unit 1 site and for evaluating the radiation exposure dose to local residents resulting from the residual radioactivity at the site after the decommissioning.
While many countries consider direct disposal of the spent nuclear fuels, they need to consider long-term disposal scenarios with severe accidents such as the contact between underwater and the spent nuclear fuel due to large defect of the canister. Radionuclides releases rapidly with contacting water or slowly with dissolution of UO2 matrix. The former is known as the ‘Instant Release’, and the latter is ‘Congruential Release’. Even though the instant release fractions (IRF) are much smaller than the congruential ones, IRF has to be treated carefully due to the fact that the instant releases lead to much larger value of the exposure dose rates than the congruential ones which proceed very slowly. It is known that the exposure dose rates by the instant releases are ~25 times larger than the one by the congruent release. The radionuclides from UO2 matrix migrate to the grain boundary, make bubbles, and make tunnels, which leads to instant releases of some radionuclides. The radionuclides in the gap between UO2 pellet and cladding can be also instantly released. In addition, the radionuclides in the crud are instantly released. But in this paper, nuclides from the crud are not regarded, due to the lack of the leaching data. Meanwhile, there’re some nuclides that released from the construction materials like the cladding, the Rod Cluster Control Assembly (RCCA), or the other metal parts. In this work, IRF values for major IRF nuclides such as Cs, I, Cl, Se for the reference PWR spent fuels of South Korea were evaluated based on the rationale from literatures’ review. In particular, these evaluations were done as the function of fission gas release (FGR), average discharge burnup, and fuel dimensions. In addition, the values of IRF for the other nuclides were also suggested based on the other institutes.
A lot of solid wastes are generated when nuclear power plant is dismantled, and a lot of treatment costs and optimal waste treatment technologies are required to treat the generated solid wastes. Currently, there is no optimized reduction and solidification technology for each characteristics of radioactive dismantling waste, so the customized treatment technology for each waste is required to respond actively to this issue. This paper shows the evaluation results of molding and sintering characteristics using preliminary sample to derive operational characteristics and improvements for powder mixing device, molding device, and sintering device manufactured for solidification of dispersible radioactive waste. Zeolite was used as a preliminary sample for performing basic operation characteristics evaluation of each unit device. First of all, the basic operation characteristics of the powder mixing device was evaluated by analyzing the sample distribution, mixing degree, and tap density. It was confirmed that the preliminary sample was well mixed in all areas of the cylinder where the mixing was performed. In the tap density analysis, the increase effect of the volume reduction of the sample was confirmed according to the increase of the RPM speed (up to 2000 RPM). Since the particle size of zeolite sample is very small (nanometer size), the particular consistency of the change of average particle size with RPM speed couldn’t be confirmed, but the uniform of particle size distribution was confirmed with RPM speed size. The basic operation characteristics of the molding device was evaluated for each mold size (ID30, ID50, ID100) according to the moisture content (0-20%) and the molding pressure condition (25-200 MPa) for the preliminary sample. In the characteristics evaluation of the sintered body, the strength of the sintered body was much higher than that of the molded body. However, it was confirmed that as moisture evaporated during the sintering process according to the moisture content contained in the molded body, the swelling occurred in the sintered body due to vapor pressure, and this caused cracks in the longitudinal or transverse direction inside and outside the sintered body. Therefore, optimal moisture content conditions for sintering should be derived. In conclusion, if the operation characteristics and improvements of powder mixing, molding and sintering devices derived from this study are reflected and improved, it is judged that it is possible to derive the optimal process for solidification of dispersive radioactive wastes.
The spent filters stored in Kori Unit 1 are planned that compressed and disposed for volume reduction. However, shielding reinforcement is required to package high-dose spent filters in a 200 L drum. So, in this study suggests a shielding thickness that can satisfy the surface dose criteria of 10 mSv·h−1 when packaging several compressed spent filters into 200 L drums, and the number of drums required for the compressed spent filter packaging was calculated. In this study, representative gamma-emitting nuclides in spent filter are assumed that Co-60 and Cs-137, and dose reduction due to half-life is not considered, because the date of occurrence and nuclide information of the stored spent filter are not accurate. The shielding material is assumed to be concrete, and the thickness of the shielding is assumed to 18 cm considering the diameter of the spent filter and compression mold. Considering the height of the compressed spent filter and the internal height of the shielding drum, assuming the placement of the compressed spent filter in the drum in the vertical direction only, the maximum number of packaging of the compressed spent filter is 3. When applying a 18 cm thick concrete shield, the maximum dose of the spent filter can packaged in the drum is 125 mSv·h−1, so when packaging 3 spent filters of the same dose, the dose of a spent filter shall not exceed 41 mSv·h−1 and not exceed 62 mSv·h−1when packing 2 spent filters. Therefore, the dose ranges of spent filters that can be packaged in a drum are classified into three groups: 0–41 mSv·h−1, 41–62 mSv·h−1, and 62–125 mSv·h−1based on 41 mSv·h−1, 62 mSv·h−1, and 125 mSv·h−1. When 227 spent filters stored in the filter room are classified according to the above dose group, 207, 3 and 4 spent filters are distributed in each group, and the number of shielding drums required to pack the appropriate number of spent filters in each dose group is 75. Meanwhile, 8 spent filters exceeding 125 mSv·h−1 and 5 spent filters that has without dose information are excluded from compression and packaging until the treatment and disposal method are prepared. In the future, we will segmentation of waste filter dose groups through the consideration of dose reduction and horizontal placement of compressed spent filters, and derive the minimum number of drums required for compressed spent filter packaging.