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被动式氚取样器性能的实验研究 总被引:1,自引:0,他引:1
介绍了核设施工作场所和环境空气中氚化水蒸气HTO的监测,被动式氚取样器在国外已经得到非常广泛的应用,所研制的被动式氚取样器,特别适用于7-30d的长期取样,给出该取样周期内空气中HTO浓度的平均值。 相似文献
3.
取样门管的特性对微波取样器性能影响的分析 总被引:1,自引:1,他引:0
本文在概述微波取样器原理的基础上,重点研究了取样门管的特性对取样器性能的影响。并通过计算机辅助分析,为取样门管参数的选取提供了理论依据。 相似文献
4.
In this paper we discuss the potentials of a new Bayesian inference tool, called the Gibbs sampler, for the analysis of the censored regression or Tobit model. Tobit models have a wide range of applications in empirical sciences, like econometrics and biometrics. The estimation results of the simple Tobit model will be compared to a hierarchical Tobit model, and the Gibbs sampling approach to the related classical algorithm of expectation-maximisation (EM). The underlying botanical example of this paper is concerned with the censoring mechanism in plant reproduction and proposes the Bayesian Tobit model for the growth relationship between the reproductive part and the rest of the plant. 相似文献
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This paper presents a wavelet-based texture segmentation method using multilayer perceptron (MLP) networks and Markov random
fields (MRF) in a multi-scale Bayesian framework. Inputs and outputs of MLP networks are constructed to estimate a posterior
probability. The multi-scale features produced by multi-level wavelet decompositions of textured images are classified at
each scale by maximum a posterior (MAP) classification and the posterior probabilities from MLP networks. An MRF model is
used in order to model the prior distribution of each texture class, and a factor, which fuses the classification information
through scales and acts as a guide for the labeling decision, is incorporated into the MAP classification of each scale. By
fusing the multi-scale MAP classifications sequentially from coarse to fine scales, our proposed method gets the final and
improved segmentation result at the finest scale. In this fusion process, the MRF model serves as the smoothness constraint
and the Gibbs sampler acts as the MAP classifier. Our texture segmentation method was applied to segmentation of gray-level
textured images. The proposed segmentation method shows better performance than texture segmentation using the hidden Markov
trees (HMT) model and the HMTseg algorithm, which is a multi-scale Bayesian image segmentation algorithm. 相似文献
7.
We propose a dynamic model for the evolution of an open animal population that is subject to an environmental catastrophe. The model incorporates a capture-recapture experiment often conducted for studying wildlife population, and enables inferences on the population size and possible effect of the catastrophe. A Bayesian approach is used to model unobserved quantities in the problem as latent variables and Markov chain Monte Carlo (MCMC) is used for posterior computation. Because the particular interrelationship between observed and latent variables negates the feasibility of standard MCMC methods, we propose a hybrid Monte Carlo approach that integrates a Gibbs sampler with the strategies of sequential importance sampling (SIS) and acceptance-rejection (AR) sampling for model estimation. We develop results on how to construct effective proposal densities for the SIS scheme. The approach is illustrated through a simulation study, and is applied to data from a mountain pygmy possum (Burramys Parvus) population that was affected by a bushfire. 相似文献
8.
介绍DCS中PID控制功能块的MAN(手动 )、AUTO(自动 )、INIT(初始化 )和OT(输出跟踪 )四种工作方式的无扰动切换。 相似文献
9.
A diagnostic procedure based on maximum likelihood estimation, to study the convergence of the Markov chain produced by Gibbs sampler, is presented. The unbiasedness, consistent and asymptotic normality are considered for the estimation of the parameters produced by the procedure. An example is provided to illustrate the procedure, and the numerical result is consistent with the theoretical one. 相似文献
10.
水利水电工程地质勘察中取土器及取样方法的探讨 总被引:1,自引:0,他引:1
为了提高工程地质勘察中提取原状土样的质量 ,针对不同的地层情况选择合理技术参数的取土器非常重要 ,本文介绍了几种取土器 ,并对所研制的取土器的管靴刃口形式的局部改进和取土方法进行了说明 相似文献