• 제목/요약/키워드: EBF

검색결과 56건 처리시간 0.022초

Gamma ray shielding characteristics and exposure buildup factor for some natural rocks using MCNP-5 code

  • Mahmoud, K.A.;Sayyed, M.I.;Tashlykov, O.L.
    • Nuclear Engineering and Technology
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    • 제51권7호
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    • pp.1835-1841
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    • 2019
  • The mass attenuation coefficient ${\mu}_m$ for eight rock samples having different chemical composition was simulated using the MCNP 5 code in energy range($0.002MeV{\leq}E{\leq}10MeV$). Moreover, the ${\mu}_m$ for the studied rock samples was computed theoretically using XCOM database. The comparison between simulated and computed data for all selected rock samples showed a good agreement with differences varied between 0.01 and 8%. The highest ${\mu}_m$ was found for basalt rocks M2 and M1 and the lowest one is reported for limestone rocks Dike. The simulated values of the ${\mu}_m$ then were used to calculate other important shielding parameters such as the mean free path, effective electron density and effective atomic number. The exposure buildup factor EBF was also computed for the selected rocks with the contribution of G-P fitting parameters and the highest EBF attended by the basalt sample Sill and varied between 1.022 and 744 in the energy range between ($0.015MeV{\leq}E{\leq}15MeV$) but the lowest EBF achieved by basalt sample M2 and varied between 1.017 and 491 in the same energy range.

Frequency Ratio와 Evidential Belief Function을 활용한 산사태 유발에 대한 환경지리적 민감성 분석과 검증 - 2013년 춘천 산사태를 중심으로 - (Analysis and Validation of Geo-environmental Susceptibility for Landslide Occurrences Using Frequency Ratio and Evidential Belief Function - A Case for Landslides in Chuncheon in 2013 -)

  • 이원영;성효현;안세진;박선기
    • 한국지형학회지
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    • 제27권1호
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    • pp.61-89
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    • 2020
  • The objective of this study is to characterize landslide susceptibility depending on various geo-environmental variables as well as to compare the Frequency Ratio (FR) and Evidential Belief Function (EBF) methods for landslide susceptibility analysis of rainfall-induced landslides. In 2013, a total of 259 landslides occurred in Chuncheon, Gangwon Province, South Korea, due to heavy rainfall events with a total cumulative rainfall of 296~721mm in 106~231 hours duration. Landslides data were mapped with better accuracy using the geographic information system (ArcGIS 10.6 version) based on the historic landslide records in Chuncheon from the National Disaster Management System (NDMS), the 2013 landslide investigation report, orthographic images, and aerial photographs. Then the landslides were randomly split into a testing dataset (70%; 181 landslides) and validation dataset (30%; 78 landslides). First, geo-environmental variables were analyzed by using FR and EBF functions for the full data. The most significant factors related to landslides were altitude (100~200m), slope (15~25°), concave plan curvature, high SPI, young timber age, loose timber density, small timber diameter, artificial forests, coniferous forests, soil depth (50~100cm), very well-drained area, sandy loam soil and so on. Second, the landslide susceptibility index was calculated by using selected geo-environmental variables. The model fit and prediction performance were evaluated using the Receiver Operating Characteristic (ROC) curve and the Area Under Curve (AUC) methods. The AUC values of both model fit and prediction performance were 80.5% and 76.3% for FR and 76.6% and 74.9% for EBF respectively. However, the landslide susceptibility index, with classes of 'very high' and 'high', was detected by 73.1% of landslides in the EBF model rather than the FR model (66.7%). Therefore, the EBF can be a promising method for spatial prediction of landslide occurrence, while the FR is still a powerful method for the landslide susceptibility mapping.

Experimental and numerical assessment of EBF structures with shear links

  • Caprili, Silvia;Mussini, Nicola;Salvatore, Walter
    • Steel and Composite Structures
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    • 제28권2호
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    • pp.123-138
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    • 2018
  • Eccentrically braced frames (EBF) represent an optimal structural solution for seismic prone areas, being able to provide high dissipative capacity and good elastic stiffness, to withstand strong seismic events without significant loss of bearing capacity and to avoid damage to non-structural elements in case of low and moderate earthquakes. The accurate knowledge of the cyclic behaviour of the dissipative links, characterizing the whole performance of EBFs, is required to optimize the structural properties and to refine the design techniques adopted for multi-storey buildings' analysis. Reliable numerical models for the links, at the same time requiring a limited computational effort, are then needed. The present work shows the results of a wide experimental test campaign executed on real-scale one storey/one bay frames with horizontal and vertical links, together with the elaboration of a simple semi-analytical model for the quick representation of the cyclic behaviour of shear links.

Block-Ordered Layered Detector for MIMO-STBC Using Joint Eigen-Beamformers and Ad-Hoc Power Discrimination Scheme

  • Lee Won-Cheol
    • Journal of Communications and Networks
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    • 제8권3호
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    • pp.275-285
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    • 2006
  • Suitable for multi-input multi-output (MIMO) communications, the joint beamforming space-time block coding (JBSTBC) scheme is proposed for high-speed downlink transmission. The major functionality of the scheme entails space-time block encoder and joint transmit and receive eigen-beamformer (EBF) incorporating with block-ordered layered decoder (BOLD), and its operating principle is described in this paper. Within these functionalities, the joint EBFs will be utilized for decorrelating fading channels to cause an enhancement in the spatial diversity gain. Furthermore, to fortify the capability of layered successive interference cancellation (LSIC) in block-ordered layered decoding process, this paper will develop a simple ad-hoc transmit power discrimination scheme (TPDS) based on a particular power discrimination function (PDF). To confirm the superior behavior of the proposed JBSTBC scheme employing ad-hoc TPDS, computer simulations will be conducted under various channel conditions with the provision of detailed mathematical derivations for clarifying its functionality.

가족 동반 아침식사에 따른 아동의 식사 다양성 평가 : 2013~2015 국민건강영양조사 자료를 이용하여 (Evaluation of the meal variety with eating breakfast together as a family in Korean children: based on 2013~2015 Korean National Health and Nutrition Examination Survey)

  • 연지영;배윤정
    • Journal of Nutrition and Health
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    • 제51권1호
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    • pp.50-59
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    • 2018
  • 본 연구는 2013 ~ 2015년 국민건강영양조사 원시자료를 활용하여, 6 ~ 11세 아동을 대상으로 성별에 따라 아침식사 가족 동반 여부 및 아침결식에 따른 영양소 및 식품군별 섭취 상태, 식사의 다양성 등을 평가하였으며, 그 결과는 다음과 같다. 연령, 체질량지수, 가구소득, 가구 세대구성 등의 일반사항은 아침식사 가족 동반 여부 및 아침결식에 따른 군간 유의한 차이를 보이지 않았고, 1일 총 열량 섭취량 역시 아침식사 가족 동반 여부 및 아침결식에 따른 군간 유의한 차이는 보이지 않았다. 그러나 남학생의 탄수화물과 비타민 C 섭취 밀도의 경우 가족 동반 아침식사군과 혼자 아침식사군이 아침결식군에 비해 유의적으로 높은 것으로 나타난 반면, 지방 섭취 밀도는 아침결식군에서 유의적으로 가장 높게 나타났다. 1일 총 식품 섭취량과 섭취한 식품의 총 가짓수 역시 남학생과 여학생 모두에서 아침식사 가족 동반 여부 및 아침결식에 따른 군간 유의한 차이는 보이지 않았다. 또한 끼니별 식품 섭취량, 음식 및 식품의 가짓수를 분석한 결과 남학생과 여학생 모두에서 가족 동반 아침식사군과 혼자 아침식사군의 아침식사로 섭취하는 음식의 가짓수가 아침결식군에 비해 유의적으로 높았으며, 남학생에서 아침식사로 섭취한 식품 가짓수의 경우 가족 동반 아침식사군이 혼자 아침식사군과 아침결식군에 비해 유의적으로 높은 결과를 보여 아침식사를 가족과 함께 하는 아동의 경우 혼자 아침식사를 하는 아동이나 아침결식을 하는 아동에 비해 섭취하는 식품이 좀 더 다양할 수 있다는 의미있는 결과를 도출하였다. 이와 같은 결과는 바람직한 영양섭취를 위한 가족 동반 아침식사의 중요성을 제안할 수 있는 근거자료가 될 수 있을 것으로 생각된다.

Hybrid simulation tests of high-strength steel composite K-eccentrically braced frames with spatial substructure

  • Li, Tengfei;Su, Mingzhou;Guo, Jiangran
    • Steel and Composite Structures
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    • 제38권4호
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    • pp.381-397
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    • 2021
  • Based on the spatial substructure hybrid simulation test (SHST) method, the seismic performance of a high-strength steel composite K-eccentrically braced frame (K-HSS-EBF) structure system is studied. First, on the basis of the existing pseudostatic experiments, a numerical model corresponding to the experimental model was established using OpenSees, which mainly simulated the shear effect of the shear links. A three-story and five-span spatial K-HSS-EBF was taken as the prototype, and SHST was performed with a half-scale SHST model. According to the test results, the validity of the SHST model was verified, and the main seismic performance indexes of the experimental substructure under different seismic waves were studied. The results show that the hybrid simulation results are basically consistent with the numerical simulation results of the global structure. The deformation of each story is mainly concentrated in the web of the shear link owing to shear deformation. The maximum interstory drifts of the model structure during Strength Level Earthquake (SLE) and Maximum Considered Earthquake (MCE) meet the demands of interstory limitations in the Chinese seismic design code of buildings. In conclusion, the seismic response characteristics of the K-HSS-EBFs are successfully simulated using the spatial SHST, which shows that the K-HSS-EBFs have good seismic performance.

Determination of buildup factors for some human tissues using both MCNP5 and Phy-X / PSD

  • Mohammad M. Alda'ajeh;J.M. Sharaf;H.H. Saleh;Mefleh S. Hamideen
    • Nuclear Engineering and Technology
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    • 제55권12호
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    • pp.4426-4430
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    • 2023
  • In this article, Exposure Buildup Factor(EBF) and the Energy Absorption Buildup Factor(EABF) have been determined for blood, brain, and muscle using the Monte Carlo method which is represented by MCNP5 codes and compared with geometric progression(G-P) fitting method which is represented by Phy-X/PSD online platform. The novelty of the present work is used an energy source of less than 0.1 MeV to determine buildup factors using MCNP5 and using Phy-X/PSD for some human tissues. thus, the energy range used in this case study was 0.06-3 MeV for penetration depths covered 0.5-3 MFP. Results of MCNP5 and Phy-X/PSD are validated against reference values of water that were reported at ANS-6.4.3. present results of EABFs and EBFs for the previously mentioned human tissues appeared good agreement between MCNP5 in comparison with Phy-X/PSD, whereas, the maximum average relative deviation did not exceed 2.37%. results of our article can be used in different medical applications, such as brachytherapy, radiotherapy, and diagnostics.

다목적 최적화 기법을 이용한 편심가새골조의 역량설계 (Capacity Design of Eccentrically Braced Frame Using Multiobjective Optimization Technique)

  • 홍윤수;유은종
    • 한국전산구조공학회논문집
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    • 제33권6호
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    • pp.419-426
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    • 2020
  • 본 연구에서는 철골편심가새골조 시스템을 대상으로 다목적최적화기법을 통해 설계를 수행하고 그 결과를 분석하였다. 최적화 설계를 위해 유전 알고리즘의 일종인 NSGA-II를 활용하였다. 여기서, 목적함수는 이율배반적 관계를 갖는 구조물량과 층간변위로 하여 최소화되고, 제약조건에는 구조기준에서 요구하는 내력비, 링크의 회전각 등을 포함하였다. 제약조건은 최적화 알고리즘 내에서 각 항목을 위반할수록 목적함수 값을 크게 증가시키는 벌금함수의 형태를 가지고 있다. 설계기준에서 EBF 시스템의 설계규정은 링크 부재만 항복이 허용되며 나머지 부재는 링크 항복 시 발생되는 부재력을 탄성상태에서 견디도록 의도한 역량설계법에 기초한다. 그러나 최적화를 통해 도출된 결과 중 일부는 구조기준의 설계조항은 만족하지만 특정층 링크에 소성변형이 집중되어 연약층을 형성함으로써 기준에서 의도하는 역량설계의 원칙을 위배하는 결과가 나타났다. 이를 해결하기 위해 모든 링크의 전단 초과강도계수 중 최대값이 최소값의 1.25배를 넘지 않도록 하는 제약식을 추가하였다. 새로운 제약식을 추가한 경우 모든 최적해는 설계기준과 역량설계의 원칙을 준수하는 것으로 나타났다. 모든 설계안에서 보 경간에 대한 링크의 길이비는 전단링크의 범주에 해당하는 10% ~ 14%였다. 전체적으로 설계안들은 링크의 초과강도 계수비가 가장 지배적인 제약으로 작용하였으며, 구조기준의 요구사항 중 층간변위와 내력비 등의 항목에서 허용치에 비해 매우 보수적으로 설계되었다.

Relationship between hardness and plastically deformed structural steel elements

  • Nashid, Hassan;Clifton, Charles;Ferguson, George;Hodgson, Micheal;Seal, Chris;Choi, Jay-Hyouk
    • Earthquakes and Structures
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    • 제8권3호
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    • pp.619-637
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    • 2015
  • A field based non-destructive hardness method is being developed to determine plastic strain in steel elements subjected to seismic loading. The focus of this study is on the active links of eccentrically braced frames (EBFs). The 2010/2011 Christchurch earthquake series, especially the very intense February 22 shaking, which was the first earthquake worldwide to push complete EBF systems into their inelastic state, generating a moderate to high level of plastic strain in EBF active links for a range of buildings from 3 to 23 storeys in height. Plastic deformation was confined to the active links. This raised two important questions: what was the extent of plastic deformation and what effect does that have on post-earthquake steel properties? A non-destructive hardness test method is being used to determine a relationship between hardness and plastic strain in active link beams. Active links from the earthquake affected, 23-storey Pacific Tower building in Christchurch are being analysed in the field and laboratory. Test results to date show clear evidence that this method is able to give a good relationship between plastic strain and demand. This paper presents significant findings from this project to investigate the relationship between hardness and plastic strain that warrant publication prior to the completion of the project. Principal of these is the discovery that hot rolled steel beams carry manufacturing induced plastic strains, in regions of the webs, of up to 5%.

Determinants of Optimal Breastfeeding Practices in Indonesia: Findings From the 2017 Indonesia Demographic Health Survey

  • Nurokhmah, Siti;Rahmawaty, Setyaningrum;Puspitasari, Dyah Intan
    • Journal of Preventive Medicine and Public Health
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    • 제55권2호
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    • pp.182-192
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    • 2022
  • Objectives: Understanding the factors influencing mothers' decision to breastfeed their infants is essential to formulate effective breastfeeding interventions. This study explored the determinants of optimal breastfeeding indicators in Indonesia. Methods: We used the 2017 Indonesia Demographic and Health Survey to analyze factors associated with early initiation of breastfeeding, exclusive breastfeeding (EBF), and continued breastfeeding at 1 year (CBF-1) and 2 years (CBF-2). Multivariate logistic regression models were used to examine bio-demographic, socio-cultural, and behavioral characteristics associated with breastfeeding after considering the survey design effect. Results: The risk of delayed breastfeeding initiation was higher among infants who were born smaller, first-born children, were delivered via cesarean delivery, and did not have immediate skin-to-skin contact (p<0.01). Infant's age, birth pattern, household wealth index, and the mother's occupation and smoking status were predictors of EBF (p<0.05). CBF-1 was less common among first-time mothers and those working in the non-agricultural sector, mothers from wealthier families, and mothers who had cesarean deliveries (p<0.01). Infant's age was negatively associated with CBF-2 (adjusted odds ratio [aOR], 0.85; 95% confidence interval [CI], 0.74 to 0.99). Mothers attending college were less likely to practice CBF-2 than those with no education or primary education (aOR, 0.45; 95% CI, 0.26 to 0.77). The absence of postnatal visits was a risk factor for CBF-1 and CBF-2 (p<0.05). Conclusions: Breastfeeding interventions in Indonesia should pay particular attention to at-risk groups such as women from wealthier families, working outside the agricultural sector, and with a higher education level. Nutrition-sensitive programs (e.g., postnatal care and smoking cessation) should also be encouraged.