• Title/Summary/Keyword: RHA

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Proposal of a Incremental Modal Pushover Analysis (IMPA)

  • Bergami, A.V.;Forte, A.;Lavorato, D.;Nuti, C.
    • Earthquakes and Structures
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    • 제13권6호
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    • pp.539-549
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    • 2017
  • Existing reinforced concrete frame buildings designed for vertical loads could only suffer severe damage during earthquakes. In recent years, many research activities were undertaken to develop a reliable and practical analysis procedure to identify the safety level of existing structures. The Incremental Dynamic Analysis (IDA) is considered to be one of the most accurate methods to estimate the seismic demand and capacity of structures. However, the executions of many nonlinear response history analyses (NL_RHA) are required to describe the entire range of structural response. The research discussed in this paper deals with the proposal of an efficient Incremental Modal Pushover Analysis (IMPA) to obtain capacity curves by replacing the nonlinear response history analysis of the IDA procedure with Modal Pushover Analysis (MPA). Firstly, In this work, the MPA is examined and extended to three-dimensional asymmetric structures and then it is incorporated into the proposed procedure (IMPA) to estimate the structure's seismic response and capacity for given seismic actions. This new procedure, which accounts for higher mode effects, does not require the execution of complex NL-RHA, but only a series of nonlinear static analysis. Finally, the extended MPA and IMPA were applied to an existing irregular framed building.

Seismic responses of hyperbolic cooling towers under horizontal and vertical earthquake

  • Zhang, Jun-Feng;Wang, Yuan-Hao;Li, Jie;Zhao, Lin
    • Earthquakes and Structures
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    • 제20권4호
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    • pp.405-415
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    • 2021
  • Following the dynamic property analysis and elaboration, linear response spectrum analysis (RSA) and response history analysis (RHA) were conducted on a representative hyperbolic cooling towers (HCT) in present study. The seismic responses in tower shell were illustrated in detail, including the internal force amplitude, modal contribution, influence from damping ratio, comparison of results got from RSA and RHA and especially the latitude distributions of internal forces. The results show that the eigenmodes could be classified in a new method into four types according to their mode shapes and only the lateral bending modes and vertical stretching modes are meaningful for horizontal and vertical earthquake correspondingly. The bending modes and seismic deformation display the same feature which is global lateral bending accompanied by minute circular flow displacement of section. This feature also decides the latitude distributions of internal forces as sine or cosine. Moreover, the following method is also proposed for approximate estimation of internal force amplitudes without time-consuming response history analysis: getting the response spectrums of the selected ground accelerations and then comparing values of response spectrums at the natural period of first lateral bending mode because it is always prime dominant for horizontal seismic responses.

Linking Social Network to Education: The Potentials and Challenges

  • RHA, Ilju;BYUN, Hyunjung;KIM, Younyoung;HONG, Seoyon
    • Educational Technology International
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    • 제13권1호
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    • pp.1-25
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    • 2012
  • Despite the relatively short history of Social Network Sites or Services (SNS), it has quickly gained popularity with more than seven hundred million users all over the globe. The SNS emerged as one of the strongest cultural influences for the contemporary society. The SNS would provide both chances and challenges for Education. The main purpose of the article was to explore the way education react and adapt to the emergence of social network and SNS. It tried to provide major theoretical grounds that bridge education and social network. In the due process, the researchers have examined the curriculum and instructional design process of education from the perspective of disruptive and sustainable aspect of SNS technology. Consequently, four major theoretical grounds were identified and reviewed: Gibson's theory of affordance, Vygotsky's social constructivism, Rha's human visual intelligence theory, and the network theory. By investigating these theories, the educational potentials of social network and SNS were emerged. The SNS was viewed as a new medium with abundant potentials of expanding the learning space, empowering the affective aspects of learning, and facilitating the formation of group intelligence. Finally, some future implications and challenges of SNS were suggested.

QTL analysis of agronomic traits in recombinant inbred lines of sunflower under partial irrigation

  • Haddadi, P.;Yazdi-Samadi, B.;Naghavi, M.R.;Kalantari, A.;Maury, P.;Sarrafi, A.
    • Plant Biotechnology Reports
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    • 제5권2호
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    • pp.135-146
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    • 2011
  • The objective of the present research was to map QTLs associated with agronomic traits such as days from sowing to flowering, plant height, yield and leaf-related traits in a population of recombinant inbred lines (RILs) of sunflower (Helianthus annuus). Two field experiments were conducted with well-irrigated and partially irrigated conditions in randomized complete block design with three replications. A map with 304 AFLP and 191 SSR markers with a mean density of 1 marker per 3.7 cM was used to identify QTLs related to the studied traits. The difference among RILs was significant for all studied traits in both conditions. Three to seven QTLs were found for each studied trait in both conditions. The percentage of phenotypic variance ($R^2$) explained by QTLs ranged from 4 to 49%. Three to six QTLs were found for each yield-related trait in both conditions. The most important QTL for grain yield per plant on linkage group 13 (GYP-P-13-1) under partial-irrigated condition controls 49% of phenotypic variance ($R^2$). The most important QTL for 1,000-grain weight (TGW-P-11-1) was identified on linkage group 11. Favorable alleles for this QTL come from RHA266. The major QTL for days from sowing to flowering (DSF-P-14-1) were observed on linkage group 14 and explained 38% of the phenotypic variance. The positive alleles for this QTL come from RHA266. The major QTL for HD (HD-P-13-1) was also identified on linkage group 13 and explained 37% of the phenotypic variance. Both parents (PAC2 and RHA266) contributed to QTLs controlling leaf-related traits in both conditions. Common QTL for leaf area at flowering (LAF-P-12-1, LAF-W-12-1) was detected in linkage group 12. The results emphasise the importance of the role of linkage groups 2, 10 and 13 for studied traits. Genomic regions on the linkage groups 9 and 12 are specific for QTLs of leaf-related traits in sunflower.

응답변위법과 응답이력해석법을 이용한 지중 공동구의 내진성능 평가 (Seismic Performance Evaluation of the Underground Utility Tunnel by Response Displacement Method and Response History Analysis)

  • 권기용;이진선;김용규;윤준웅;정순용
    • 한국지반공학회논문집
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    • 제36권11호
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    • pp.119-133
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    • 2020
  • 지중공동구는 대표적인 개착식 지중구조물로, 지진시 지반의 변위로 인한 지진력이 작용하는 구조물이다. 시설안전기술공단에서는 2020년에 기존 시설물(공동구) 내진성능 평가요령을 제정하여 배포하였다. 본 논문에서는 내진성능평가요령에서 제시하고 있는 두 가지 성능평가방법인 응답변위법과 응답이력해석기법을 소개하고, 대표 공동구에 대해서 두 가지 내진성능평가방법을 적용하여 그 결과를 비교·검토 하였다. 평가에 사용된 공동구는 1988년 건설되어 내진설계가 적용되지 않은 공동구 이다. 응답변위법은 기반면 속도응답스펙트럼으로부터 단일코사인과 이중코사인 방법을 적용하여 내진성능평가를 실시하였다. 응답이력해석은 지반과 구조재료 모두 비선형 거동을 나타낼 수 있는 유한차분해석프로그램을 사용하여 2차원 평면변형율 해석을 시행하였다. 붕괴방지 수준의 지진에 대한 성능평가 결과 응답변위법은 구조물이 탄성범위내 거동하는 것으로 평가되는 반면, 응답이력해석은 구조물 일부에서 소성힌지가 발생하는 결과를 나타내었다.

지능형 스토리텔링을 위한 저작에 관한 연구 (A Study of Authoring for Intelligent Storytelling)

  • 라창현;하얀
    • 한국지능시스템학회:학술대회논문집
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    • 한국퍼지및지능시스템학회 2005년도 추계학술대회 학술발표 논문집 제15권 제2호
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    • pp.456-459
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    • 2005
  • 본 논문은 디지털 시대에 스토리텔링을 위한 적합한 지능형 스토리텔링 저작도구를 제안하고자 한다. 미국 등지에서는 이미 디지털 스토리텔링 제품이 많이 개발이 되어 실제 작품 제작에 활용되고 있으나, 국내에서는 아직 시도된 바가 없다. 또한 국외의 제품을 국내 창작환경에 활용하고자 할 때, 국내 작가 입장에서 적절하게 활용이 불가능한 상황이다. 따라서, 본 연구에서는 국내형 스토리텔링을 위한 저작도구를 개발하고자 하며, 이를 위한 지능형에 관한 연구를 제안하고자 한다.

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Characteristics of Phytolith on Rice Leaf

  • Rha, Eui-Shik;Kim, Jin-Key
    • 한국작물학회지
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    • 제43권4호
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    • pp.205-208
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    • 1998
  • Silica bodies (phytoliths) are becoming of wide use for pedology, archaeology, paleobotany and paleoecology in botany. This study investigated morphological differences of silica bodies in the lamina of wild, indica type, and japonica type rice. Phytoliths in the epidermis of lamina showed noticeable difference among tested plants. Besides, there were also significant differences in the shape and distribution of the silica bodies around stomata and trichomes. Silica bodies in the lamina of the rice plants could be used to classify subspecies of Oryza genus.

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