• 제목/요약/키워드: Fixed model test

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The Effect of Economic Growth and Urbanization on Poverty Reduction in Vietnam

  • NGUYEN, Huyen Thi Thanh;NGUYEN, Chau Van;NGUYEN, Cong Van
    • The Journal of Asian Finance, Economics and Business
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    • 제7권7호
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    • pp.229-239
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    • 2020
  • This article aims to measure the impact of economic growth and urbanization on poverty reduction in Vietnam, and verify whether economic growth and urbanization will help reduce poverty rates. Data for this study are tabular data related to growth, urbanization and poverty at the provincial level for the period of nine years, from 2006 to 2014 provided by the Vietnam General Statistics Office and the Vietnam General Department of Customs. The level of economic growth and urbanization mentioned in the study is reflected in such indicators as GDP value, exports value, imports value, urbanization rate and employment rate. The authors used logistic regression models with fixed-effects and logistic regression models with random effects. With 5% confidence level tested by the Chi-Square test of Hausman trial with the fixed-effect model, research results show that: (1) factors with significant negative impact on the poverty rate include imports value, urbanization rate and, employment rate; (2) factors that do not affect the poverty rate include exports value and GDP value. Based on the research results, this study proposes a number of policy recommendations to help promote economic growth, to sustain the urbanization process, and to contribute directly and positively to poverty reduction in Vietnam.

수정된 밀도함수법을 이용한 고정된 반잠수식 해양구조물 주위 유동의 수치시뮬레이션 (Numerical Simulation of Flow around a Fixed Semi-submersible Offshore Structure Using the Modified Marker-density Method)

  • 하윤진;이영길;정광열;양인준
    • 대한조선학회논문집
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    • 제53권1호
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    • pp.1-9
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    • 2016
  • It is important to research and understand the physical phenomenon around a semi-submersible offshore structure on waves and currents because the wave run-up and load occurs owing to the waves and currents. In this study, the numerical simulations are performed about flow around a fixed semi-submersible offshore structure. The Modified Marker-density method is adopted in the present computation procedure, this method is one of the various methods to define the free-surface. The present computation results are compared with existing experimental and numerical simulation(VOF method) results. And, the computation results are relatively coincident with the existing results of model test and numerical simulation by VOF method.

Neuro-fuzzy and artificial neural networks modeling of uniform temperature effects of symmetric parabolic haunched beams

  • Yuksel, S. Bahadir;Yarar, Alpaslan
    • Structural Engineering and Mechanics
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    • 제56권5호
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    • pp.787-796
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    • 2015
  • When the temperature of a structure varies, there is a tendency to produce changes in the shape of the structure. The resulting actions may be of considerable importance in the analysis of the structures having non-prismatic members. The computation of design forces for the non-prismatic beams having symmetrical parabolic haunches (NBSPH) is fairly difficult because of the parabolic change of the cross section. Due to their non-prismatic geometrical configuration, their assessment, particularly the computation of fixed-end horizontal forces and fixed-end moments becomes a complex problem. In this study, the efficiency of the Artificial Neural Networks (ANN) and Adaptive Neuro Fuzzy Inference Systems (ANFIS) in predicting the design forces and the design moments of the NBSPH due to temperature changes was investigated. Previously obtained finite element analyses results in the literature were used to train and test the ANN and ANFIS models. The performances of the different models were evaluated by comparing the corresponding values of mean squared errors (MSE) and decisive coefficients ($R^2$). In addition to this, the comparison of ANN and ANFIS with traditional methods was made by setting up Linear-regression (LR) model.

75톤급 액체로켓엔진 축소형 가스발생기 연소시험 (Hot-firing Tests of Subscale Gas Generator for 75 ton-class Liquid Rocket Engine)

  • 김문기;서성현;안규복;임병직;김종규;이광진;한영민;최환석
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2010년도 제34회 춘계학술대회논문집
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    • pp.173-176
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    • 2010
  • 75톤급 가스발생기 기술검증시제에서 나타난 산화제 분사기 차압의 증가 원인을 파악하기 위하여 축소형 가스발생기를 설계, 제작하였다. 설계점 및 탈설계점 시험 조건을 포함한 총 6회의 연소시험을 성공적으로 수행하였다. 연소시험 결과 연소압을 고정한 후 혼합비를 증가시킨 경우 연료 및 산화제 유량계수는 일정한 것으로 나타났으며, 혼합비를 고정한 후 연소압을 증가시킨 경우에도 연료 및 산화제 유량계수는 변함이 없는 것으로 파악되었다.

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혼합모형의 추정가능함수 (Estimable functions of mixed models)

  • 최재성
    • 응용통계연구
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    • 제29권2호
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    • pp.291-299
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    • 2016
  • 본 논문은 고정요인과 확률요인의 혼합모형에서 추정가능함수를 논의하고 있다. 고정효과모형에서 정의된 추정가능 함수가 혼합효과모형에서 어떻게 정의되어야 하는 가를 규정하고 추정가능함수의 분산추정치를 구하는 방법을 제시하고 있다. 또한 혼합모형에서 분산성분의 추정을 위한 제곱합의 계산에 상수적합법을 이용하고 추론을 위한 자유도의 계산에 Satterthwaite의 근사화를 다루고 있으며 분산성분을 구하기 위한 모형의 적합방식으로 단계별 방법을 적용하고 있다. 모형의 단계별 적합에서 주어지는 모형행렬의 사영을 이용한 제1종 제곱합의 계산방식이 제공되며 사영을 이용한 변동요인별 제1종 제곱합의 기댓값 계산에 Hartley의 합성법이 논의된다.

수직 등분포 하중을 받는 고정 지점 포물선 아치 리브의 면내 좌굴 강도 (In-plane buckling strength of fixed arch ribs subjected vertical distributed loading)

  • 문지호;윤기용;김성훈;이학은
    • 한국강구조학회 논문집
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    • 제17권4호통권77호
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    • pp.439-447
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    • 2005
  • 아치 리브가 수직 하중을 받는 경우, 예기치 않게 면내 방향으로 좌굴이 발생될 수 있다. 따라서 설계자는 아치 리브의 면내 안정성을 설계 시 반드시 고려해야 한다. 본 논문에서는 유한 요소 해석을 통하여 수직 등분포 하중을 받는 고정지점 포물선 아치 리브의 탄성, 비탄성 면내 좌굴 강도를 연구하였다. 본 연구에서 사용된 아치 리브의 스냅-스루 현상과 비탄성 거동을 모사하기 위한 유한 요소 해석 모델은 기존 연구자들의 실험 결과를 이용하여 검증되었다. 또한 아치 리브의 면내 극한 강도를 결정하기 위하여 대변형과 재료의 비탄성, 잔류응력을 고려하였으며, 마지막으로 유한 요소 해석의 결과를 EC3 설계기준과 비교, 분석 하였다.

Selective adsorption of Ba2+ using chemically modified alginate beads with enhanced Ba2+ affinity and its application to 131Cs production

  • Kim, Jin-Hee;Lee, Seung-Kon
    • Nuclear Engineering and Technology
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    • 제54권8호
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    • pp.3017-3026
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    • 2022
  • The 131Cs radioisotope with a short half-life time and high average radiation energy can treat the cancer effectively in prostate brachytherapy. The typical 131Cs production processes have a separation step of the cesium from 131Ba to obtain a high specific radioactivity. Herein, we suggested a novel 131Cs separation method based on the Ba2+ adsorption of alginate beads. It is necessary to reduce the affinity of alginate beads to cesium ions for a high production yield. The carboxyl group of the alginate beads was replaced by a sulfonate group to reduce the cesium affinity while reinforcing their affinity to barium ions. The modified beads exhibited superior Ba2+ adsorption performances to native beads. In the fixed-bed column tests, the saturation time and adsorption capacity could be estimated with the Yoon-Nelson model in various injection flow rates and initial concentrations. In terms of the Cs elution, the modified alginate showed better performance (i.e., an elution over 88%) than the native alginate (i.e., an elution below 10%), indicating that the functional group modification was effective in reducing the affinity to cesium ions. Therefore, the separation of cesium from the barium using the modified alginate is expected to be an additional option to produce 131Cs.

The development of food image detection and recognition model of Korean food for mobile dietary management

  • Park, Seon-Joo;Palvanov, Akmaljon;Lee, Chang-Ho;Jeong, Nanoom;Cho, Young-Im;Lee, Hae-Jeung
    • Nutrition Research and Practice
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    • 제13권6호
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    • pp.521-528
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    • 2019
  • BACKGROUND/OBJECTIVES: The aim of this study was to develop Korean food image detection and recognition model for use in mobile devices for accurate estimation of dietary intake. MATERIALS/METHODS: We collected food images by taking pictures or by searching web images and built an image dataset for use in training a complex recognition model for Korean food. Augmentation techniques were performed in order to increase the dataset size. The dataset for training contained more than 92,000 images categorized into 23 groups of Korean food. All images were down-sampled to a fixed resolution of $150{\times}150$ and then randomly divided into training and testing groups at a ratio of 3:1, resulting in 69,000 training images and 23,000 test images. We used a Deep Convolutional Neural Network (DCNN) for the complex recognition model and compared the results with those of other networks: AlexNet, GoogLeNet, Very Deep Convolutional Neural Network, VGG and ResNet, for large-scale image recognition. RESULTS: Our complex food recognition model, K-foodNet, had higher test accuracy (91.3%) and faster recognition time (0.4 ms) than those of the other networks. CONCLUSION: The results showed that K-foodNet achieved better performance in detecting and recognizing Korean food compared to other state-of-the-art models.

대한민국 FTA체결에 따른 부산항 벌크물동량 영향분석 : 칠레, 페루, 싱가포르, 인도, 미국을 중심으로 (The Impact of Bilateral Free Trade Agreements on International Trade Volume of Bulk Shipment at the Port of Busan in Korea : Focusing on Korea's FTA with Chile, Peru, Singapore, India, and United States)

  • 이경한;박주동
    • 한국항만경제학회지
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    • 제32권3호
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    • pp.83-94
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    • 2016
  • 본 연구에서는 한국과 총 5개 단일국가(칠레, 싱가포르, 인도, 페루, 미국) 간 FTA 발효가 부산항 벌크물동량에 미치는 영향에 대한 실증분석을 시도하였다. 분석을 위해 대한민국과 FTA가 발효된 5개 국가(효과집단)와 2015년 기준 부산항 벌크물동량 교역 상위 80%의 비중을 차지하는 10개 국가(통제집단)의 횡단면 및 시계열로 구성된 패널자료를 사용하였다. 분석 결과 FTA 발효는 부산항 벌크물동량의 증대에 기여한 것으로 나타났다. FTA 이외의 GDP, 인구 변수는 부산항 벌크물동량과 양(+)의 효과를 보이는 것으로 나타났으며, 거리 변수는 물동량과 음(-)의 효과를 보이는 것으로 분석되었다. 국가별 패널자료는 하우스만 검정 및 LR검정을 통해 확률효과모형이 적합한 것으로 나타났다.

Genetic parameters of milk and lactation curve traits of dairy cattle from research farms in Thailand

  • Pangmao, Santi;Thomson, Peter C.;Khatkar, Mehar S.
    • Animal Bioscience
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    • 제35권10호
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    • pp.1499-1511
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    • 2022
  • Objective: This study was aimed to estimate the genetic parameters, including genetic and phenotypic correlations, of milk yield, lactation curve traits and milk composition of Thai dairy cattle from three government research farms. Methods: The data of 25,789 test-day milk yield and milk composition records of 1,468 cattle from lactation 1 to 3 of Holstein Friesian (HF) and crossbred HF dairy cattle calved between 1990 and 2015 from three government research farms in Thailand were analysed. 305-day milk yield was estimated by the Wood model and a test interval method. The Wood model was used for estimating cumulative 305-day milk yield, peak milk yield, days to peak milk yield and persistency. Genetic parameters were estimated using linear mixed models with herd, breed group, year and season of calving as fixed effects, and animals linked to a pedigree as random effects, together with a residual error. Univariate models were used to estimate variance components, heritability, estimated breeding values (EBVs) and repeatability of each trait, while pairwise bivariate models were used to estimate covariance components and correlations between traits in the same lactation and in the same trait across lactations. Results: The heritability of 305-day milk yield, peak milk yield and protein percentage have moderate to high estimates ranging from 0.19 to 0.45 while days to peak milk yield, persistency and fat percentage have low heritability ranging from 0.08 to 0.14 in lactation 1 cows. Further, heritability of most traits considered was higher in lactation 1 compared with lactations 2 and 3. For cows in lactation 1, high genetic correlations were found between 305-day milk yield and peak milk yield (0.86±0.07) and days to peak milk yield and persistency (0.99±0.02) while estimates of genetic correlations between the remaining traits were imprecise due to the high standard errors. The genetic correlations within the traits across lactation were high. There was no consistent trend of EBVs for most traits in the first lactation over the study period. Conclusion: Both the Wood model and test interval method can be used for milk yield estimates in these herds. However, the Wood model has advantages over the test interval method as it can be fitted using fewer test-day records and the estimated model parameters can be used to derive estimates of other lactation curve parameters. Milk yield, peak milk yield and protein percentage can be improved by a selection and mating program while days to peak milk yield, persistency and fat percentage can be improved by including into a selection index.