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Ratio Method (ratio + method)
Selected AbstractsA probabilistic approach for earthquake potential evaluation based on the load/unload response ratio methodCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 12 2010Huai-Zhong Yu Abstract Previous studies indicate that the occurrence of a large earthquake might be predicted by anomalous temporal increase of the load/unload response ratio (LURR), which was often defined as the ratio of Benioff strain of small earthquakes released during loading and unloading time periods, corresponding to earth tide-induced Coulomb failure stress change on optimally oriented faults. The conventional LURR anomalous evaluation usually sets a critical LURR value, above which an earthquake may occur. In this paper a probabilistic approach for the evaluation of earthquake potential based on the LURR method is developed. In the approach, the occurrence probability of a future earthquake is quantitatively evaluated by assessing the confidence level of LURR anomaly associated with its stochastic distribution. As retrospective studies, we apply the approach to investigate the time series of LURR prior to the 50M>6.3 earthquakes that occurred in the Chinese mainland and the 21M>6.0 earthquakes in southern California over the past 30 years, and find high correlation between the confidence level of the LURR anomalies and the occurrence of the large earthquakes. We then depict all the high peaks that appeared in the LURR time series, and evaluate the earthquake occurrence rate as a function of the confidence level. The research results show considerable promise that our probabilistic approach may provide a useful tool to evaluate quantitatively the occurrence possibilities of future earthquakes. Copyright © 2009 John Wiley & Sons, Ltd. [source] The silver(I)-catalyzed exchange of coordinated cyanide in hexacyanoferrate(II) by phenylhydrazine in aqueous mediumINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 8 2007R. M. Naik The [Ag]+ -catalyzed exchange of coordinated cyanide in [Fe(CN)6]4, by phenylhydrazine (PhNHNH2) has been studied spectrophotometrically at 488 nm by monitoring increase in the absorbance for the formation of cherry red colored complex [Fe(CN)5PhNHNH2]3,. The other reaction conditions were pH 2.80±,0.02, temperature = 30.0 ± 0.1°C, and ionic strength (I) = 0.02 M (KNO3). The reaction was followed as a function of pH, ionic strength, temperature, [Fe(CN)4,6], [PhNHNH2], [Ag+] by varying one variable at a time. The initial rates were evaluated for each variation using the plane mirror method. The initial rates evaluated as a function of [Fe(CN)4,6] clearly indicate that the initial rate increases with the increase in [Fe(CN)4,6] and finally reaches to a limiting value when [Fe(CN)4,6]/[AgNO3] , 1000. It indicates the formation of a strong adduct between [Fe(CN)6]4, and AgNO3 prior to the abstraction of CN,. The variation in initial rates with [PhNHNH2] also showed limiting values at [Fe(CN)4,6]/[PhNHNH2] , 8.30. The complex behavior due to pH and [Ag+] variations on the rate has been explained in detail. The composition of the final reaction product [Fe(CN)5PhNHNH2] formed during the course of reaction has been found to be 1:1 using the mole ratio method. The evaluated values of activation parameters for the catalyzed reaction are Ea = 53.85 kJ mol,1, , H,, = 51.33 kJ mol,1, and , S, = ,134.63 J K,1 mol,1, which suggest an interchange dissociative mechanism. A most plausible mechanistic scheme has been proposed based on the experimental observations. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 447,456, 2007 [source] A new framework for data reconciliation and measurement bias identification in generalized linear dynamic systemsAICHE JOURNAL, Issue 7 2010Hua Xu Abstract This article describes a new framework for data reconciliation in generalized linear dynamic systems, in which the well-known Kalman filter (KF) is inadequate for filtering. In contrast to the classical formulation, the proposed framework is in a more concise form but still remains the same filtering accuracy. This comes from the properties of linear dynamic systems and the features of the linear equality constrained least squares solution. Meanwhile, the statistical properties of the framework offer new potentials for dynamic measurement bias detection and identification techniques. On the basis of this new framework, a filtering formula is rederived directly and the generalized likelihood ratio method is modified for generalized linear dynamic systems. Simulation studies of a material network present the effects of both the techniques and emphatically demonstrate the characteristics of the identification approach. Moreover, the new framework provides some insights about the connections between linear dynamic data reconciliation, linear steady state data reconciliation, and KF. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] On the neglecting of higher-order cumulants in EXAFS data analysisJOURNAL OF SYNCHROTRON RADIATION, Issue 6 2009A. Sanson The cumulant expansion is one of the most powerful and useful methods for EXAFS data analysis, in which the higher-order cumulants allow to consider deviations from a simple Gaussian distribution. In this work, analytical expressions have been derived to show the effects of neglecting higher-order cumulants in EXAFS analysis by the ratio method. The errors in the best-fitting procedure owing to the omission of the higher-order cumulants, as well as of the coordination number, can be determined. [source] A review and discussion of prospective statistical surveillance in public healthJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES A (STATISTICS IN SOCIETY), Issue 1 2003Christian Sonesson Summary. A review of methods suggested in the literature for sequential detection of changes in public health surveillance data is presented. Many researchers have noted the need for prospective methods. In recent years there has been an increased interest in both the statistical and the epidemiological literature concerning this type of problem. However, most of the vast literature in public health monitoring deals with retrospective methods, especially spatial methods. Evaluations with respect to the statistical properties of interest for prospective surveillance are rare. The special aspects of prospective statistical surveillance and different ways of evaluating such methods are described. Attention is given to methods that include only the time domain as well as methods for detection where observations have a spatial structure. In the case of surveillance of a change in a Poisson process the likelihood ratio method and the Shiryaev,Roberts method are derived. [source] Determination of nucleic acid by [tetra-(3-methoxy-4-hydroxyphenyl)],Tb3+ porphyrin as the fluorescence spectral probe in bis(2-ethylhexyl)sulfosuccinate sodium salt micelle systemLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 4 2009Xin Chen Abstract A new system for the determination of nucleic acid by rare earth metallic porphyrin of [tetra-(3-methoxy-4-hydroxyphenyl)],Tb3+ [T(3-MO-4HP),Tb3+] porphyrin as fluorescence spectral probe has been developed in this paper. Nucleic acid can enhance the fluorescence intensity of the T(3-MO-4HP),Tb3+ porphyrin in the presence of bis(2-ethylhexyl)sulfosuccinate sodium salt(AOT) micelle. In pH 8.00 Tris,HCl buffer solution, under optimum conditions, the enhanced fluorescence intensity is in proportion to the concentration of nucleic acids in the range of 0.05,3.00 µg mL,1 for calf thymus DNA (ct DNA) and 0.03,4.80 µg mL,1 for fish sperm DNA(fs DNA). Their detection limits are 0.03 and 0.01 µg mL,1, respectively. In addition, the binding interaction mechanism between T(3-MO-4HP),Tb3+ porphyrin and ct DNA is also investigated by resonance scattering and fluorescence spectra. The maximum binding number is calculated by molar ratio method. The new system can be used for the determination of nucleic acid in pig liver, yielding satisfactory results. Copyright © 2009 John Wiley & Sons, Ltd. [source] False Discovery Rate Estimation for Frequentist Pharmacovigilance Signal Detection MethodsBIOMETRICS, Issue 1 2010I. Ahmed Summary Pharmacovigilance systems aim at early detection of adverse effects of marketed drugs. They maintain large spontaneous reporting databases for which several automatic signaling methods have been developed. One limit of those methods is that the decision rules for the signal generation are based on arbitrary thresholds. In this article, we propose a new signal-generation procedure. The decision criterion is formulated in terms of a critical region for the P-values resulting from the reporting odds ratio method as well as from the Fisher's exact test. For the latter, we also study the use of mid-P-values. The critical region is defined by the false discovery rate, which can be estimated by adapting the P-values mixture model based procedures to one-sided tests. The methodology is mainly illustrated with the location-based estimator procedure. It is studied through a large simulation study and applied to the French pharmacovigilance database. [source] | |||||||||||||