• 제목/요약/키워드: Tail Model

검색결과 379건 처리시간 0.03초

Jackknife Estimation in an Exponential Model

  • Woo, Jung-Soo
    • Journal of the Korean Data and Information Science Society
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    • 제15권1호
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    • pp.193-200
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    • 2004
  • Parametric estimation of truncated point in a truncated exponential distribution will be considered. The MLE, bias reducing estimator and the ordinary jackknife estimator of the truncated parameter will be compared by mean square errors. And the MME and MLE of mean parameter and estimations of the right tail probability in the distribution will be compared by their MSE's.

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Association of a Single Codon Deletion in Bone Morphogenetic Protein 15 Gene with Prolificacy in Small Tail Han Sheep

  • Guo, W.;Chu, M.X.;Deng, X.M.;Feng, J.D.;Li, Ning;Wu, Changxin
    • Asian-Australasian Journal of Animal Sciences
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    • 제17권11호
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    • pp.1491-1495
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    • 2004
  • Small Tail Han Sheep has significant characteristics of high prolificacy and non-seasonal ovulatory activity and is an excellent local sheep breed in P. R. China. Recently a novel member of the transforming growth factor $\beta$ (TGF$\beta$) superfamily termed bone morphogenetic protein 15 (BMP15) was shown to be specifically expressed in oocytes and to be essential for female fertility. Therefore, BMP15 is a candidate gene for reproductive performance of Small Tail Han Sheep. The whole genomic nucleotide sequence of BMP15 gene in Small Tail Han Sheep was searched for polymorphisms by PCR-SSCP and direct sequencing, and only one polymorphism was found. The polymorphism was a result of a 3 base pair deletion, which eliminated a single Leu codon (CTT). The allelic frequencies for A (without deletion) and B (with a codon deletion) are 0.73 and 0.27 respectively. The effects of BMP15 genotype on litter size were evaluated using the least squares model. This indicated that there was a significant association between litter size of Small Tail Han Sheep and a deletion in BMP15 gene (p=0.02<0.05). Small Tail Han Sheep ewes with AA and AB genotype produce on average 0.5 and 0.3 more lambs per litter than those ewes with BB genotype.

내성 및 의존성 형성 약물의 약효 검색

  • 김학성;오기완
    • 한국응용약물학회:학술대회논문집
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    • 한국응용약물학회 1993년도 제2회 신약개발 연구발표회 초록집
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    • pp.77-77
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    • 1993
  • 약물 내성 (tolerance) 및 의존성 (dependence)은 그 약물이 지니고 있는 여러 가지 약리작용과 관련되어 형성된다. 약물의 반복투여 후, 나타나는 작용이 처음의 반응 (response) 보다 감소되어 나타나는 현상 즉, 내성과, 이와는 반대로 약물반복 투여 후 나타나는 작용이 처음의 반응보다 점점 증가하는 역내성 (reverse tolerance 또는 sensitization) 측정에 있어서 약물에 따라 적절한 검색 방법을 설명한다. 의존성에 있어서 약물 섭취 결과 mood가 변하거나 도취감 또는 만족감을 일으키게 되면 그 감각을 재 경험하고 싶다는 욕구가 일어나게 되는 정신적 의존성(psychic dependence)과, 약물을 반복 투여하다가 갑자기 투여를 중단 했을때 여러가지 생리학적인 또는 행동적인 변화가 급격히 증가하여 금단증상을 나타내는 신체적 의존성 (physical dependence) 측정 방법을 제시한다. 내성과 의존성은 근본적으로 다르지만 대부분의 경우 내성이 형성되면 의존성이 형성된다. 여기서는 주로 morphine과 psychostimulants를 투여한 후 나타나는 약리작용에 대한 내성과 opioids (마약성 진통제)의 의존성 평가 방법에 대한 model을 설명하고자 한다 진통성 내성(analgesic tolerance)에 있어서 진통제의 진통력은 진통력 측정 방법(tail pinch, paw-withdrawal, tail flick, tail-withdrawal, hot plate, writhing, etc)에 따라 차이가 있기 때문에 각각의 진통제의 정합한 내성 측정 방법을 결정할 필요가 있다. 역내성 (roversetolerance)은 cocaine, amphetamine, opioids둥의 만성투여에서 일어난다. 이들 역내성을 측정하는 한 방법으로 자발운동을 측정하는데 locomotor activity cage나 tilting cage를 이용한다. 정신적 의존성(psychic dependence)은 약물 섭취 욕구를 이용한 CPP (conditioned place preference)법을 소개한다. 신체적 의존성 (physical dependence)은 opioids를 만성적으로 투여한 후 naloxone으로 precipitation하여 나타난 여러 가지 금단증상을 측정하고 몇몇 평가 model을 제시한다.

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E-tail Uses and Gratifications to Understand Apparel Consumers

  • Park, Jee-Sun;Lee, Kyu-Hye
    • 복식문화연구
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    • 제20권2호
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    • pp.272-285
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    • 2012
  • The purpose of the study is to examine the role of consumer perceptions of websites' entertainment and informativeness in developing their attitudes (attitude toward the retailer and attitude confidence toward the product) in the context of apparel e-tailing. A structural equation model was developed for an empirical test based on the literature on uses-and-gratifications and attitude confidence. A sample of 119 consumers who live in the United States participated in the online survey. The results generally supported the proposed model. Specifically, the analyses revealed that consumers' purchase intention toward the displayed product is positively influenced by their attitudes toward the retailer and by their confidence in their attitudes toward the product. Interestingly, only one of the two cognitive antecedents, perceived entertainment, has a positive impact on consumers' attitude toward the retailer. Perceived informativeness, however, had a positive impact on attitude confidence. These findings suggest that consumers who have high perception of an e-tail website's entertainment are more likely to exhibit favorable attitudes toward the e-tailer, while consumers who have high perception of an e-tail website's informativeness are more likely to hold strong confidence in their attitudes toward the product displayed on the website. Both consumer attitudes toward the e-tailer and their attitude confidence lead to their purchase intentions.

축대칭체 주위 고 레이놀즈수 유동에 대한 수치해석 (Numerical Analysis of High-Reynolds-Number Flow around Axisymmetric Body)

  • 최정규;김형태
    • 대한조선학회논문집
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    • 제45권6호
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    • pp.631-636
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    • 2008
  • In this paper, numerical analysis based on the RANS equation and the Realizable ${\kappa}-{\varepsilon}$ turbulence model is carried out for flows around an axisymmetric body at three Reynolds numbers($1.22{\times}10^7$, $1.0{\times}10^8$, $1.5{\times}10^8$) and the numerical results are compared with experiments data. Computed velocity distributions agree well with experiments as the Reynolds number increases. Pressure distributions agree well with the results of the potential flow except the tail region but differ from experiments for the parallel middle body as well as tail region. Pressure gradients show a good agreement with those of potential flow and experiment except the tail region. Friction coefficients show that the numerical results generally are lower than the experimental results estimated from the measured velocity. The difference of friction coefficients between the calculation and the experiment increases with growing of a boundary layer.

The U.S. Contagion Effects on Foreign Direct Investment Flows in Developing Countries

  • HEMA, Itsarawadee;OSATHANUNKUL, Rossarin
    • The Journal of Asian Finance, Economics and Business
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    • 제8권4호
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    • pp.55-67
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    • 2021
  • This study aims to measure the lower tail dependence as risk contagion from the U.S. economy to 18 developing countries affecting FDI inflows using time-series data from 2005 to 2019. Firstly, we utilize four dynamic copula models, namely, Student-t, Clayton, rotated survival Gumbel, and rotated survival Joe, to measure the tail dependence structure between the U.S. and each developing country's real GDP growth. Secondly, we use the regression model to explore the contagion effects on FDI inflows. The results show that there is evidence of the tail dependence between the U.S and developing economies, indicating the presence of the contagion effects. Primarily, we observe that the degree of contagion effects of the global financial crisis varies across countries; a strong impact is observed in Chinese, South African, Russian, Colombian, and Mexican economic growth. Furthermore, we found significant contagion risk affecting FDI inflows positively in China, Indonesia, Columbia, Morocco, and negatively in the Philippines, Bulgaria, and South Africa. This study demonstrates the usefulness of the copulas model in terms of examining contagion. Our findings shed light on the influence of sound policies and regulations to cope with both positive and negative consequences of the contagion on the capital movement.

쉴드터널에서의 뒷채움주입에 관한 연구 (A Study on Backfill Injection of Shield Tunnelling)

  • 민덕기;백진욱
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 1995년도 가을 학술발표회 논문집
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    • pp.201-210
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    • 1995
  • In Resent years, urban tunnels have been more deeply constructed due to the congestion of buried steuctures. In such conditions, the shield method has become one of the popular urban tunnelling method by reason of several characteristics ; safety of construction, mimium environmental damage, and workbility. In tunnelling, the space which is tail-void are created between the ground and the other face of the primary lining. in other to reduce the ground seformation, it is important backfilling in tail-void. In this paper, the result of an experimental investigation undertaken to evaluate the physical and mechanical propeties of grouts composed of various mixtures of backfill materials. And the backfill injection model test was carried out considering the effects of tail-void.

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Time Resolved Infrared Spectroscopy of Electro-optic Switching of 5CB

  • Jang, Won-Gun
    • Journal of Information Display
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    • 제5권1호
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    • pp.34-40
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    • 2004
  • Time resolved infrared IR absorption spectroscopy is carried out to investigate the dynamics of electric field induced reorientation of the biphenyl molecular core and alkyl tail sub-fragments of the nematic liquid crystal 5CB (4-pentyl-4-cyano-biphenyl). The planar to homeotropic transition for high pre-tilt planar aligned cells, is studied for switching times ranging from 200 ${\mu}sec$ down to 80 ${\mu}sec$, the latter a factor of 1000 times faster than any previous nematic IR study. The reorientation rates of the core and tail are found to be the same to within experimental error and scale inversely with applied field squared, as expected for the balance of field and viscous torques. Thus any molecular conformation change during switching must relax on a shorter time scale. A simple model shows that no substantial differences exist between the reorientational dynamics of the tails and cores on the time scales longer than on the order of 10 ${\mu}s$.

Utilizing a unit Gompertz distorted copula to model dependence in anthropometric data

  • Fadal Abdullah Ali Aldhufairi
    • Communications for Statistical Applications and Methods
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    • 제30권5호
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    • pp.467-483
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    • 2023
  • In this research, a conversion function and a distortion associated with the conversion function are defined and used to derive a unit power Gompertz distortion. A new family of copulas is built using the global distorted function. Four base copulas, namely Clayton, Gumbel, Frank, and Gaussian, are distorted into the family. Some properties including tail dependence coefficients and tail order are examined. Kendall's tau formula is derived for new copulas when the base copula is Clayton, Gumbel, or Frank. The maximum pseudo-likelihood estimation method is employed, and a simulation study was performed. The log-likelihood and AIC are reported to compare the performance of the fitted copulas. According to the applied data, the results indicate that new distorted copulas with additional parameters improve the fit.

열연강판 선후단부 폭 정밀도 개선을 위한 최적 엣저롤 개도 제어 (Dynamic Edger Control for the Precise Width Control at the Head, and Tail Ends of Hot Strip)

  • 천명식;이준정;문영훈
    • 대한기계학회논문집A
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    • 제23권7호
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    • pp.1196-1204
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    • 1999
  • adaption of the model predictions is highly desirable. In general, the width deviation at the head and tail ends of strip may be different from that of the steady state region. Therefore, the dynamic edger corrections can be used to compensate the width deviations which would otherwise occur. For the precise width control, the effect of edger roll gap and rolling conditions on the width deviation of head and tail ends of strip has been investigated and the effective method to decrease width deviation has been proposed. On-line application of dynamic edger control method in this study shows about 50% width compensation at the head end of the strip, and near perfect compensation at the tail end of strip.