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1.
韩立军 《内蒙古工业大学学报》2002,21(1):50-52
本文给出一类非均匀弦的横向振动的最佳控制,推广了P C Park的结果。这一结果同样适用于同类型振动问题。 相似文献
2.
李海群 《长江大学学报(社会科学版)》2002,(2)
该电路设计简单、构思新颖 ,适合小批量测试小型电源变压器的空载电流、额定电流及次级空载电压、满载电压、负载电流等参数 相似文献
3.
We propose some estimators of noncentrality parameters which improve upon usual unbiased estimators under quadratic loss. The distributions we consider are the noncentral chi-square and the noncentral F. However, we give more general results for the family of elliptically contoured distributions and propose a robust dominating estimator. 相似文献
4.
BAYESIAN SUBSET SELECTION AND MODEL AVERAGING USING A CENTRED AND DISPERSED PRIOR FOR THE ERROR VARIANCE 总被引:1,自引:0,他引:1
Edward Cripps Robert Kohn David Nott 《Australian & New Zealand Journal of Statistics》2006,48(2):237-252
This article proposes a new data‐based prior distribution for the error variance in a Gaussian linear regression model, when the model is used for Bayesian variable selection and model averaging. For a given subset of variables in the model, this prior has a mode that is an unbiased estimator of the error variance but is suitably dispersed to make it uninformative relative to the marginal likelihood. The advantage of this empirical Bayes prior for the error variance is that it is centred and dispersed sensibly and avoids the arbitrary specification of hyperparameters. The performance of the new prior is compared to that of a prior proposed previously in the literature using several simulated examples and two loss functions. For each example our paper also reports results for the model that orthogonalizes the predictor variables before performing subset selection. A real example is also investigated. The empirical results suggest that for both the simulated and real data, the performance of the estimators based on the prior proposed in our article compares favourably with that of a prior used previously in the literature. 相似文献
5.
洋桔梗叶盘高频率不定芽诱导的初步研究 总被引:1,自引:0,他引:1
采用正交设计法研究了细胞分裂素ZT,生长素NAA,培养基pH值和光照强度对洋桔梗叶盘不定芽诱导的影响.结果表明,实验的4个因子对洋桔梗叶盘不定芽都具有极显著的诱导作用,最佳培养基和培养条件为:MS ZT 0.5 mg/L NAA 0.01 mg/L,培养基pH值为6.3,光照强度为3000 lx.该处理中每叶盘再生不定芽数平均达9.41个. 相似文献
6.
Jan C. H. van Eijkeren 《Risk analysis》2002,22(1):159-173
A mechanistic model is presented describing the clearance of a compound in a precision-cut liver slice that is incubated in a culture medium. The problem of estimating metabolic rate constants in PBPK models from liver slice experiments is discussed using identifiability analysis. From the identifiability problem analysis, it appears that in addition to the clearance, the compound's free fraction in the slice and the diffusion rate of the exchange of the compound between culture medium and liver slice should be identified. In addition, knowledge of the culture medium volume, the slice volume, the compound's free fraction, and octanol-water-based partition between medium and slice is presupposed. The formal solution for identification is discussed from the perspective of experimental practice. A formally necessary condition for identification is the sampling of parent compound in liver slice or culture medium. However, due to experimental limitations and errors, sampling the parent compound in the slice together with additional sampling of metabolite pooled from the medium and the slice is required for identification in practice. Moreover, it appears that identification results are unreliable when the value of the intrinsic clearance exceeds the value of the diffusion coefficient, a condition to be verified a posteriori. 相似文献
7.
吴晟 《湖南人文科技学院学报》2005,(4):42-44
经过近几年来高校管理体制的大幅度调整变化,目前湖南省省属高校所采用的经常性财政拨款方案已不能适应新形式的需要。成为适时之需,构建一种公平合理、简单有效的新模式,既发挥财政拨款在高教事业中的基础作用,又引导高校不断提高办学效益。 相似文献
8.
Peter J. Robinson 《Risk analysis》1992,12(1):139-148
Because of the inherent complexity of biological systems, there is often a choice between a number of apparently equally applicable physiologically based models to describe uptake and metabolism processes in toxicology or risk assessment. These models may fit the particular data sets of interest equally well, but may give quite different parameter estimates or predictions under different (extrapolated) conditions. Such competing models can be discriminated by a number of methods, including potential refutation by means of strategic experiments, and their ability to suitably incorporate all relevant physiological processes. For illustration, three currently used models for steady-state hepatic elimination--the venous equilibration model, the parallel tube model, and the distributed sinusoidal perfusion model--are reviewed and compared with particular reference to their application in the area of risk assessment. The ability of each of the models to describe and incorporate such physiological processes as protein binding, precursor-metabolite relations and hepatic zones of elimination, capillary recruitment, capillary heterogeneity, and intrahepatic shunting is discussed. Differences between the models in hepatic parameter estimation, extrapolation to different conditions, and interspecies scaling are discussed, and criteria for choosing one model over the others are presented. In this case, the distributed model provides the most general framework for describing physiological processes taking place in the liver, and has so far not been experimentally refuted, as have the other two models. These simpler models may, however, provide useful bounds on parameter estimates and on extrapolations and risk assessments. 相似文献
9.
张秋勇 《绍兴文理学院学报》2002,22(7):97-100
运用机械动态参数测试仪 ,通过对THEMA剑杆织机的开口、引纬机构进行动态测试 ,利用计算机处理有关测试数据 ,分析和讨论了该机的主要技术参数 相似文献
10.
从实时系统的需求出发,研究利用遗传算法实现实时模糊控制的新技术,包括规则的形成、前提参数的训练,通过对比不同的训练参数规模,讨论了训练参数规模的大小与模型“范化”之间的关系。 经检验,用遗传算法生成的模糊系统模型输入变量少、规则数目少,并且误差小于多数传统算法生成的模型,整个模型的形成过程时间空间复杂度小、易于控制,且不受经验知识的约束,适用于实时系统。 相似文献