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961.
On potentially negative space time covariances obtained as sum of products of marginal ones 总被引:1,自引:0,他引:1
P. Gregori E. Porcu J. Mateu Z. Sasvári 《Annals of the Institute of Statistical Mathematics》2008,60(4):865-882
Most of the literature on spatio-temporal covariance models proposes structures that are positive in the whole domain. However,
problems of physical, biological or medical nature need covariance models allowing for negative values or oscillations from
positive to negative values. In this paper, we propose an easy-to-implement and interpretable class of models that admits
this type of covariances. We show particular analytical examples that may be of interest in the biometrical context.
Work partially funded by grants GV04A724 (Generalitat Valenciana) and MTM2004-06231 (Spanish Ministry of Science and Education). 相似文献
962.
利用小波分析预测方法对金融数据—股票收盘价这一典型的非平稳时间序列进行预测.使用M a llat小波分解算法对数据进行分解,对分解后的数据进行平滑处理,然后再进行重构,而重构之后的数据就成为近似意义的平稳时间序列,这样就得到了原始数据的近似信号,再应用传统时间序列预测方法对重构后的数据进行预测,将预测结果与实际值,以及和传统预测方法预测结果比较,小波分析方法预测效果更为理想. 相似文献
963.
研究了带阻尼项一维非等熵流方程组的初边值问题,利用能量估计的办法证明了整体解的存在性和得到在L2-模及L∞-模意义下解的大时间状态稳定性估计。 相似文献
964.
黄永年 《宁波大学学报(理工版)》2000,13(4):5-10
分析了连续时间和离散时间的捕食-被捕食模型:Hassel and Rogers的狼与鹿相互作用的模型,发现它们的轨线有一定程度的相似,但从生态意义上讲,离散模型更合适。 相似文献
965.
CpTiCl2(OC6H4X‐p) complexes (where X =CH3, Cl, NO2,; Cp = cyclopentadienyl) activated with methylaluminoxane (MAO) were used in syndiotactic polymerization of styrene. High activity and selectivity for all catalysts were found. The styrene conversion and reaction selectivity depend on the catalyst ageing time and temperature, polymerization temperature and the nature of the substituent in the phenoxy ring. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
966.
D. Loss 《Journal of statistical physics》1990,59(3-4):691-723
The quantum-statistical generalization of the well-known classical, linear revised Enskog equation is derived for spatially uniform systems. This new quantum kinetic equation allows the study of equilibrium time correlation functions and their associated transport coefficients of normal quantum fluids where static correlations and degeneracy effects due to particle statistics (both are treated exactly) are important. Furthermore, we derive the quantum-statistical analog of the classical ring operator. These microscopic and systematic derivations are based on a recently developed superoperator formalism (including cluster expansion techniques) that, as a main feature, allows a clear distinction between static and dynamic correlations, which is crucial in the discussion of the Enskog approximation. 相似文献
967.
Yves Van Ingelgem Els Tourwé Orlin Blajiev Rik Pintelon Annick Hubin 《Electroanalysis》2009,21(6):730-739
Electrochemical impedance spectroscopy (EIS) is a powerful technique to study electrochemical processes and to perform screening tasks. Recently an integrated measuring and modeling methodology for EIS based on a multisine excitation signal was developed. A key issue in this methodology is the data analysis, allowing us to rapidly quantify the reliability of the measured data. In this paper, a comparison is made between classical single‐sine and the proposed multisine measurements on the same system. The fitting of the impedance data obtained by single‐or multisine excitation and using different weighting factors is also discussed. In addition to the advantages reported in earlier work, it is concluded that, of all investigated frequencies, the odd random phase multisine excitation yields the highest quality data in the shortest measurement time. 相似文献
968.
Qiu Tianshuang Wang Hongyu 《电子科学学刊(英文版)》1997,14(3):279-284
Multipath time delay estimation is constrained by the width of the signal correlation function when using correlation based methods. This paper obtains a high resolution time delay estimation by introducing Burg algorithm and Marple algorithm of the maximum entropy power spectral estimation to non-resolvable multipath time delay estimatoin. The principles, the performaces and the results of computer simulation are given. 相似文献
969.
970.