Generalized sensitivity indices based on vector projection for multivariate output

2019 ◽  
Vol 66 ◽  
pp. 592-610 ◽  
Author(s):  
Liyang Xu ◽  
Zhenzhou Lu ◽  
Sinan Xiao
Keyword(s):  
Sensitivity Indices ◽  
Vector Projection ◽  
Generalized Sensitivity

scholarly journals The new importance measures based on vector projection for multivariate output: application on hydrological model

2016 ◽  
Author(s):  
Liyang Xu ◽  
Zhenzhou Lu ◽  
Sinan Xiao
Keyword(s):  
Polynomial Chaos ◽  
Hydrological Model ◽  
Sufficient Information ◽  
Decomposition Approach ◽  
Mathematical Properties ◽  
Sensitivity Indices ◽  
Vector Projection ◽  
Potential Benefits ◽  
Input Variables ◽  
Output Space

Abstract. Analyzing the effects of the inputs on the correlated multivariate output is important to assess risk and make decisions in Hydrological processes. However, the existing methods, such as output decomposition approach and covariance decomposition approach, cannot provide sufficient information of the effects of the inputs on the multivariate output, since these methods only measure the influence of input variables on the magnitudes of variances of the dimensionalities in the multiple output space and ignore the effects on the dimensionality directions of output variances. In this paper, a new kind of sensitivity indices based on vector projection for the multivariate output is proposed. By the projection of the conditional vectors on the unconditional vector in the dimensionless multiple output space, the new sensitivity indices measure the influence of the input variables on the magnitudes of variances and directions of the dimensionalities simultaneously. The mathematical properties of the proposed index are discussed, and its link with the Sobol indices is derived. And Polynomial Chaos Expansion (PCE) is used to estimate the proposed sensitivity indices. The results for two numerical examples and a hydrological model indicate the validity and potential benefits of the vector projection index and the efficiency of estimation approach.

scholarly journals Certified metamodels for sensitivity indices estimation

2012 ◽  
Vol 35 ◽  
pp. 234-238 ◽  
Author(s):  
Alexandre Janon ◽  
Maëlle Nodet ◽  
Clémentine Prieur
Keyword(s):  
Sensitivity Indices

scholarly journals Extrachromosomal elements cause a reduced division potential in nib 1 strains of Saccharomyces cerevisiae.

Genetics ◽  
1989 ◽  
Vol 122 (4) ◽  
pp. 749-757
Author(s):  
R Sweeney ◽  
V A Zakian
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Open Reading Frames ◽  
Simultaneous Presence ◽  
Extrachromosomal Elements ◽  
Severe Reduction ◽  
Extrachromosomal Element ◽  
Generalized Sensitivity ◽  
Reading Frames

Abstract The nib 1 allele of yeast confers a sensitivity to an endogenous plasmid, 2 mu DNA, in that nib 1 strains bearing 2 mu DNA (cir+) exhibit a reduction in division potential. In the present study, the reduction in division potential characteristic of nib 1 cir+ strains is shown to be dependent on the simultaneous presence of both the A and the D open reading frames of 2 mu DNA as well as on the presence of an unidentified extrachromosomal element other than 2 mu DNA. Furthermore, in nib 1 strains, an uncharacterized extrachromosomal element can cause a less severe reduction of division potential in the absence of intact 2 mu DNA. Thus, the nib 1 allele may confer a generalized sensitivity to extrachromosomal elements.

scholarly journals Sensitivity Analysis for Microscopic Crowd Simulation

Algorithms ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 162
Author(s):  
Marion Gödel ◽  
Rainer Fischer ◽  
Gerta Köster
Keyword(s):  
Sensitivity Analysis ◽  
Low Cost ◽  
Input Parameter ◽  
Dimensional Subspace ◽  
Crowd Simulation ◽  
Pedestrian Dynamics ◽  
Sensitivity Indices ◽  
Expensive Problems ◽  
Influential Parameters ◽  
Typical Scenario

Microscopic crowd simulation can help to enhance the safety of pedestrians in situations that range from museum visits to music festivals. To obtain a useful prediction, the input parameters must be chosen carefully. In many cases, a lack of knowledge or limited measurement accuracy add uncertainty to the input. In addition, for meaningful parameter studies, we first need to identify the most influential parameters of our parametric computer models. The field of uncertainty quantification offers standardized and fully automatized methods that we believe to be beneficial for pedestrian dynamics. In addition, many methods come at a comparatively low cost, even for computationally expensive problems. This allows for their application to larger scenarios. We aim to identify and adapt fitting methods to microscopic crowd simulation in order to explore their potential in pedestrian dynamics. In this work, we first perform a variance-based sensitivity analysis using Sobol’ indices and then crosscheck the results by a derivative-based measure, the activity scores. We apply both methods to a typical scenario in crowd simulation, a bottleneck. Because constrictions can lead to high crowd densities and delays in evacuations, several experiments and simulation studies have been conducted for this setting. We show qualitative agreement between the results of both methods. Additionally, we identify a one-dimensional subspace in the input parameter space and discuss its impact on the simulation. Moreover, we analyze and interpret the sensitivity indices with respect to the bottleneck scenario.

Product-Oriented Sensitivity Analysis for Multistation Compliant Assemblies

2006 ◽  
Vol 129 (8) ◽  
pp. 844-851 ◽  
Author(s):  
Jianpeng Yue ◽  
Jaime A. Camelio ◽  
Melida Chin ◽  
Wayne Cai
Keyword(s):  
Product Performance ◽  
Sensitivity Index ◽  
Final Assembly ◽  
Sensitivity Indices ◽  
Dimensional Variation ◽  
Product And Process ◽  
Pattern Sensitivity ◽  
Sheet Metal Assembly

Dimensional variation in assembled products directly affects product performance. To reduce dimensional variation, it is necessary that an assembly be robust. A robust assembly is less sensitive to input variation from the product and process components, such as incoming parts, subassemblies, fixtures, and welding guns. In order to effectively understand the sensitivity of an assembly to input variation, an appropriate set of metrics must be defined. In this paper, three product-oriented indices, including pattern sensitivity index, component sensitivity index, and station sensitivity index, are defined. These indices can be utilized to measure the variation influence of a pattern, an individual part, and/or component, and components at a particular station to the dimensional quality of a final assembly. Additionally, the relationships among these sensitivity indices are established. Based on these relationships, the ranges of the sensitivity indices are derived. Finally, a case study of a sheet metal assembly is presented and discussed to illustrate the applicability of these metrics.

scholarly journals Chronic kidney disease and obesity bias surrogate estimates of insulin sensitivity compared with the hyperinsulinemic euglycemic clamp

2017 ◽  
Vol 312 (3) ◽  
pp. E175-E182 ◽  
Author(s):  
Iram Ahmad ◽  
Leila R. Zelnick ◽  
Nicole R. Robinson ◽  
Adriana M. Hung ◽  
Bryan Kestenbaum ◽  
...  
Keyword(s):  
Chronic Kidney Disease ◽  
Insulin Sensitivity ◽  
Kidney Disease ◽  
Oral Glucose ◽  
Cross Sectional ◽  
Euglycemic Clamp ◽  
Insulin Kinetics ◽  
Hyperinsulinemic Euglycemic Clamp ◽  
Sensitivity Indices ◽  
Organ Specific

Insulin sensitivity can be measured by procedures such as the hyperinsulinemic euglycemic clamp or by using surrogate indices. Chronic kidney disease (CKD) and obesity may differentially affect these measurements because of changes in insulin kinetics and organ-specific effects on insulin sensitivity. In a cross-sectional study of 59 subjects with nondiabetic CKD [estimated glomerular filtration rate: (GFR) <60 ml·min−1·1.73 m2] and 39 matched healthy controls, we quantified insulin sensitivity by clamp (SIclamp), oral glucose tolerance test, and fasting glucose and insulin. We compared surrogate insulin sensitivity indices to SIclamp using descriptive statistics, graphical analyses, correlation coefficients, and linear regression. Mean age was 62.6 yr; 48% of the participants were female, and 77% were Caucasian. Insulin sensitivity indices were 8–38% lower in participants with vs. without CKD and 13–59% lower in obese compared with nonobese participants. Correlations of surrogate indices with SIclamp did not differ significantly by CKD or obesity status. Adjusting for SIclamp in addition to demographic factors, Matsuda index was 15% lower in participants with vs. without CKD ( P = 0.09) and 36% lower in participants with vs. without obesity ( P = 0.0001), whereas 1/HOMA-IR was 23% lower in participants with vs. without CKD ( P = 0.02) and 46% lower in participants with vs. without obesity ( P < 0.0001). We conclude that CKD and obesity do not significantly alter correlations of surrogate insulin sensitivity indices with SIclamp, but they do bias surrogate measurements of insulin sensitivity toward lower values. This bias may be due to differences in insulin kinetics or organ-specific responses to insulin.

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