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Analytical method to estimate cross-section stress profiles for reactor vessel nozzle corners under internal pressure

  • Oh, Changsik;Lee, Sangmin;Jhung, Myung Jo
    • Nuclear Engineering and Technology
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    • v.54 no.1
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    • pp.401-413
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    • 2022
  • This paper provides a simple method by which to estimate the cross-section stress profiles for nozzles designed according to ASME Code Section III. Further, this method validates the effectiveness of earlier work performed by the authors on standard nozzles. The method requires only the geometric information of the pressure vessel and the attached nozzle. A PWR direct vessel injection nozzle, a PWR outlet nozzle, a PWR inlet nozzle and a BWR recirculation outlet nozzle are selected based on their corresponding specific designs, e.g., a varying nozzle radius, a varying nozzle thickness and an outlet nozzle boss. A cross-section stress profile comparison shows that the estimates are in good agreement with the finite element analysis results. Differences in stress intensity factors calculated in accordance with ASME BPVC Section XI Appendix G are discussed. In addition, a change in the dimensions of an alternate nozzle design relative to the standard values is discussed, focusing on the stress concentration factors of the nozzle inside corner.

A Novel Online Multi-section Weighed Fault Matching and Detecting Algorithm Based on Wide-area Information

  • Tong, Xiaoyang;Lian, Wenchao;Wang, Hongbin
    • Journal of Electrical Engineering and Technology
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    • v.12 no.6
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    • pp.2118-2126
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    • 2017
  • The large-scale power system blackouts have indicated that conventional protection relays that based on local signals cannot fit for modern power grids with complicated setting or heavily loaded-flow transfer. In order to accurately detect various faulted lines and improve the fault-tolerance of wide-area protection, a novel multi-section weighed fault matching and detecting algorithm is proposed. The real protection vector (RPV) and expected section protection vectors (ESPVs) for five fault sections are constructed respectively. The function of multi-section weighed fault matching is established to calculate the section fault matching degrees between RPV and five ESPVs. Then the fault degree of protected line based on five section fault degrees can be obtained. Two fault detecting criterions are given to support the higher accuracy rate of detecting fault. With the enumerating method, the simulation tests illustrate the correctness and fault-tolerance of proposed algorithm. It can reach the target of 100% accuracy rate under 5 bits error of wide-area protections. The influence factors of fault-tolerance are analyzed, which include the choosing of wide-area protections, as well as the topological structures of power grid and fault threshold.

Modeling and prediction of buckling behavior of compression members with variability in material and/or section properties

  • Gadalla, M.A.;Abdalla, J.A.
    • Structural Engineering and Mechanics
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    • v.22 no.5
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    • pp.631-645
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    • 2006
  • Buckling capacity of compression members may change due to inadvertent changes in the member section dimensions or material properties. This may be the result of repair, modification of section properties or degradation of the material properties. In some occasions, enhancement of buckling capacity of compression members may be achieved through splicing of plates or utilization of composite materials. It is very important for a designer to predict the buckling resistance of the compression member and the important parameters that affect its buckling strength once changes in section and/or material properties took place. This paper presents an analytical approach for determining the buckling capacity of a compression member whose geometric and/or material properties has been altered resulting in a multi-step non-uniform section. This analytical solution accommodates the changes and modifications to the material and/or section properties of the compression member due to the factors mentioned. The analytical solution provides adequate information and a methodology that is useful during the design stage as well as the repair stage of compression members. Three case studies are presented to show that the proposed analytical solution is an efficient method for predicting the buckling strength of compression members that their section and/or material properties have been altered due to splicing, coping, notching, ducting and corrosion.

An evaluation of stream naturalness for Close-to-nature stream restoration -In case of Suwon stream- (자연형 하천복원을 위한 하천자연도 평가 -수원천을 중심으로-)

  • Kim, Dong-Chan;Lee, Jung;Park, Il-Su
    • Journal of the Korean Institute of Landscape Architecture
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    • v.27 no.5
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    • pp.138-149
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    • 2000
  • The purpose of this study is to evaluate Suwon stream naturalness Index(S.N.I). and tofind out stats, problems and opportunities of the Suwon stream by assessment standard. Assessment standard is mainly based on physical structure of stream environment. the purpose evaluating sectors and elements are physical form and structure restoration of stream. To find out assessment standard of stream naturalness index, conceptual frame of assessment standard has been established, for which four sections, for example, longitudinal section, lateral section, stream bottom structure and water environment, have been selected. Overall stream naturalness index of the Suwon stream has been distributed at 3rd to 4th grade, and 3.3 of assessment index and mode were 3rd grade respectively. stream naturalness index of each section was as follows: Longitudinal section accounted for 3.7in average to be 4th grade, lateral section did 3.8 to be 4th grade, and water environment did 2.4 to be 2nd grade. Analysis of assessment outcome of stream naturalness index has checked status, problems and opportunities of corresponding stream. Assessment of stream naturalness index of the study provides useful information for restoration of close-to-nature stream, and furthermore has its meaning in checking problems and opportunities of Suwon stream.

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Effects of Diagnosis-Related Group-Based Payment System on the Risk-Adjusted Cesarean Section Rate (Diagnosis-Related Group 지불제도가 위험도 보정 제왕절개 분만율에 미치는 영향)

  • Kwak, Jin-Mi;Lee, Kwang-Soo
    • Health Policy and Management
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    • v.31 no.2
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    • pp.180-187
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    • 2021
  • Background: This study analyzed the effect of applying the diagnosis-related group (DRG)-based payment system, which was implemented in July 2012 for hospitals and clinics nationwide, on the cesarean section rate. Methods: The subjects of the study were divided into new groups that participated in the payment system after July 2012 and maintenance groups that participated in the payment system before July 2012. As an analysis method, a difference-in-difference analysis, which is a quasi-experimental design, was used. The risk-adjusted cesarean section rate was used as a dependent variable. Results: Seven risk factors (malpresentation of fetus, eclampsia, multiple pregnancies, problems in the placenta, previous Cesarean section, cephalopelvic disproportion, problems in amniotic fluid) were included in the final risk-adjustment model, and found to have a statistically significant relationship with the cesarean section rate. Results showed that the risk-adjusted cesarean section rate increased significantly in new groups after the application of the DRG-based payment system. Conclusion: Study results provided policy implications for the reorganization of the DRG-based system should that reflects the demands of obstetricians, such as organizing a consultative body with obstetricians and establishing a reasonable fee.

3D Shape Reconstruction from Microscopic Serial Section Images (현미경 섹션 영상으로부터 3차원 형상 복구 기법)

  • 윤일동;이후성
    • Proceedings of the IEEK Conference
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    • 2003.07e
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    • pp.2379-2382
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    • 2003
  • This paper describes the design, implementation and results of a unified non-rigid image registration method for the purposes of 3D shape reconstruction from serial section images. The proposed method uses active contour-based segmentation and compensation of radial distortion. Experimental results show that multiple images can be segmented and reconstructed by active single contour as well as intra- and inter-section registration.

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Sound recognition and tracking system design using robust sound extraction section (주변 배경음에 강인한 구간 검출을 통한 음원 인식 및 위치 추적 시스템 설계)

  • Kim, Woo-Jun;Kim, Young-Sub;Lee, Gwang-Seok
    • The Journal of the Korea institute of electronic communication sciences
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    • v.11 no.8
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    • pp.759-766
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    • 2016
  • This paper is on a system design of recognizing sound sources and tracing locations from detecting a section of sound sources which is strong in surrounding environmental sounds about sound sources occurring in an abnormal situation by using signals within the section. In detection of the section with strong sound sources, weighted average delta energy of a short section is calculated from audio signals received. After inputting it into a low-pass filter, through comparison of values of the output result, a section strong in background sound is defined. In recognition of sound sources, from data of the detected section, using an HMM(: Hidden Markov Model) as a traditional recognition method, learning and recognition are realized from creating information to recognize sound sources. About signals of sound sources that surrounding background sounds are included, by using energy of existing signals, after detecting the section, compared with the recognition through the HMM, a recognition rate of 3.94% increase is shown. Also, based on the recognition result, location grasping by using TDOA(: Time Delay of Arrival) between signals in the section accords with 97.44% of angles of a real occurrence location.

Educational Status and Students' Educational Needs on the Food and Nutrition Section of Technology.Home Economics Subject at Middle Schools in the Daejeon Area (대전지역 중학교의 기술.가정교과 "식생활단원"교육에 대한 교육실태 및 학습요구도)

  • Lee, Joon-Ho
    • The Korean Journal of Community Living Science
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    • v.21 no.4
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    • pp.559-569
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    • 2010
  • This study investigated the educational status, students' recognition, educational needs and degree of difficulty on the food and nutrition section of Technology Home economics subject in middle schools. It was carried out through questionnaires. The subjects were 503(boys; 246, girls; 257) middle school students in 3rd grade in the Daejeon area. The results were as follows. The students' preference for food and nutrition section was 58.5% of boys and 72.0% of girls. On the educational status of this section, The highest cooking frequency was once a year(52.3%), but 12.9% of students had never done cooking practice. Generally, practice education was not enough in subjected schools. The education of food and nutrition section was mainly conducted by lecture. For the behavioral change of students after learning this section, 'I can cook some simple foods' was the most(36.8%) than the other. The contents of high educational needs in this section were 'cooking foods' and ‘basic cooking methods'. A average degree of difficulty in this section was 2.89 points of the likert scale(1~5 point), particularly, 'change of food components by cooking' was the highest at 3.17 points of likert scale(1~5 point) in this degree. In relation to demographic background, the difficult degrees of this section were significantly higher than the other, when their parent's education was under middle school and their fathers' had no occupation. It suggests an increase in cooking frequency, complementing contents needed in life and using various audio-visual education aids are necessary for the education of food and nutrition section.

Integrated Code Classification System for Work Sections in Standard Method of Measurement and Construction Standard Specifications (수량산출기준 및 공사시방서의 공종분류코드 통합기준 연구)

  • Kang Leen-Seok;Kwak Joong-Min
    • Korean Journal of Construction Engineering and Management
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    • v.2 no.4 s.8
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    • pp.80-91
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    • 2001
  • Considering that the classified items in the work section level can have an applicability when those items are being used to cost and specification information with consistency, the work section classification code should be applied as an Integrated code system. Our construction industry is using three work section classification systems for civil engineering projects, such as integrated construction information classification system, standard method of measurement and guide of project specification. And each standard construction specification is also using different work section classification systems. This study suggests a methodology to integrate the code systems in construction specifications with civil engineering standard method of measurement. And the methodology suggested in this study was applied to a web-based prototype system with practical specification codes.

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Development of Cross Section Management System in Tunnel using Terrestrial Laser Scanning Data (지상 레이저 스캐닝 자료를 이용한 터널단면관리시스템 개발)

  • Roh, Tae-Ho;Kim, Jin-Soo;Lee, Young-Do
    • Journal of the Korean Association of Geographic Information Studies
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    • v.11 no.1
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    • pp.90-104
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    • 2008
  • Laser scanning technology with high positional accuracy and high density will be widely applied to vast range of fields including geomatics. Especially, the development of laser scanning technology enabling long range information extraction is increasing its full use in civil engineering. This study taps into the strengths of a terrestrial laser scanning technique to develop a tunnel cross section management system that can be practically employed for determining the cross section of tunnels more promptly and accurately. Three dimensional data with high density were obtained in a prompt and accurate manner using a terrestrial laser scanner. Data processing was then conducted to promptly determine arbitrary cross sections at 0.1meter, 0.5meter and 1.0meter intervals. A laser scanning technique was also used to quickly and accurately calculate the overbreak and underbreak of both each cross section and the entire tunnel section. As the developed system utilizes vast amounts of data, it was possible to promptly determine the shape of arbitrary cross section and to calculate the overbreak and underbreak more accurately with higher area precision. It is expected, therefore, that the system will not only enable more efficient and cost effective tunnel drilling management and monitoring but also will provide a basis for future construction and management of tunnel cross section.

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