Simulation-based sensitivity analysis for causal mediation studies.

2021 ◽  
Author(s):  
Xu Qin ◽  
Fan Yang
Keyword(s):  
Sensitivity Analysis ◽  
Causal Mediation ◽  
Simulation Based

Sensitivitätsanalyse des Fördergutverhaltens*/Sensitivity analysis of transported material – Physics simulation based analysis of bulk material related to the topology of vibratory bowl feeders

2015 ◽  
Vol 105 (09) ◽  
pp. 622-626
Author(s):  
C. Stocker ◽  
G. Reinhart
Keyword(s):  
Sensitivity Analysis ◽  
Future Development ◽  
Development Process ◽  
Bulk Material ◽  
Automated Generation ◽  
Simulation Based ◽  
The Future ◽  
Physics Simulation ◽  
Material Physics ◽  
Transported Material

Vibrationswendelförderer (VWF) sind die meistverwendeten Systeme zur automatisierten Vereinzelung und Zuführung von Schüttgut. Zur Verbesserung der derzeit manuellen Entwicklung, werden Methoden zur Simulation von VWF erforscht. Der Fachartikel stellt eine physiksimulationsbasierte Sensitivitätsanalyse des Förderguts bezüglich der Topologie im VWF vor. Die Ergebnisse dieser Analyse dienen als Basis für die Entwicklung eines Verfahrens zur automatischen Generierung von Ordnungsschikanen.   Vibratory bowl feeders (VBF) are the most frequently used systems for automated sorting and feeding of bulk material. To improve the current manual development process, methods for simulation of VBF are researched. The presented paper introduces a physics simulation based sensitivity analysis of the behavior of transported parts related to the topology of the VBF. These results provide a basis for the future development of an algorithm for the automated generation of orienting devices.

Bayesian sensitivity analysis for unmeasured confounding in causal mediation analysis

2017 ◽  
Vol 28 (2) ◽  
pp. 515-531 ◽  
Author(s):  
Lawrence C McCandless ◽  
Julian M Somers
Keyword(s):  
Sensitivity Analysis ◽  
Mediation Analysis ◽  
Indirect Effects ◽  
Direct And Indirect Effects ◽  
Unmeasured Confounding ◽  
Intermediate Variable ◽  
Causal Mediation ◽  
Important Concern ◽  
Analysis Technique ◽  
Causal Mediation Analysis

Causal mediation analysis techniques enable investigators to examine whether the effect of the exposure on an outcome is mediated by some intermediate variable. Motivated by a data example from epidemiology, we consider estimation of natural direct and indirect effects on a survival outcome. An important concern is bias from confounders that may be unmeasured. Estimating natural direct and indirect effects requires an elaborate series of assumptions in order to identify the target quantities. The analyst must carefully measure and adjust for important predictors of the exposure, mediator and outcome. Omitting important confounders may bias the results in a way that is difficult to predict. In recent years, several methods have been proposed to explore sensitivity to unmeasured confounding in mediation analysis. However, many of these methods limit complexity by relying on a handful of sensitivity parameters that are difficult to interpret, or alternatively, by assuming that specific patterns of unmeasured confounding are absent. Instead, we propose a simple Bayesian sensitivity analysis technique that is indexed by four bias parameters. Our method has the unique advantage that it is able to simultaneously assess unmeasured confounding in the mediator–outcome, exposure–outcome and exposure–mediator relationships. It is a natural Bayesian extension of the sensitivity analysis methodologies of VanderWeele, which have been widely used in the epidemiology literature. We present simulation findings, and additionally, we illustrate the method in an epidemiological study of mortality rates in criminal offenders from British Columbia.

Experiment and Simulation Analysis of the Pressure Carrying Capacity of X80 Pipe with Metal Loss Defect on the Girth Weld

2021 ◽  
Vol 1035 ◽  
pp. 813-818
Author(s):  
Zheng Long Li ◽  
Lin Chen ◽  
Zhi Hong Li ◽  
Guo Shuai Yan ◽  
Wei Li
Keyword(s):  
Sensitivity Analysis ◽  
Carrying Capacity ◽  
Simulation Analysis ◽  
Water Pressure ◽  
Metal Loss ◽  
Factors Affecting ◽  
Element Simulation ◽  
Simulation Based ◽  
Blasting Test ◽  
Water Pressure Blasting

In order to study the pressure carrying capacity of X80 pipe with metal loss defect on the girth weld the water-pressure blasting test of the pipe with metal loss defect was analyzed by experiment and finite element simulation. Based on this, the sensitivity analysis of the factors affecting the pressure carrying of the pipeline, such as the circular size, the axial size, and the depth of the metal loss defect, was carried out. The research results show that the circular size of the metal loss defect on the girth weld had little impact to the pressure carrying capacity of the pipe while it reduced with the increasing of the axial size and the depth of the metal loss defect.

Simulation Analysis of the Pressure Carrying Capacity of X80 Pipe with Plain Dents

2019 ◽  
Vol 944 ◽  
pp. 835-840
Author(s):  
Peng Song ◽  
Zheng Long Li ◽  
Yu Ran Fan ◽  
Lei Guo ◽  
Xi Xi Zhang ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Finite Element ◽  
Internal Pressure ◽  
Carrying Capacity ◽  
Formation Process ◽  
Simulation Analysis ◽  
Hydraulic Test ◽  
Factors Affecting ◽  
Element Simulation ◽  
Simulation Based

In order to study the pressure carrying capacity of X80 pipe with plain dents, the formation process and the hydraulic test were analyzed by finite element simulation. Based on this, the sensitivity analysis of the factors affecting the pressure carrying capacity of the pipeline, such as the internal pressure, the confinement state and the material performance, is carried out. Research results show that springback amount of the pipeline decreases due to the initial internal pressure, and constraint state has little effect on the pressure carrying capacity while increases with the increasing of the material tensile properties. When the depth of the dent is less than 6% pipe diameter or the strain of the dent is less than 6%, the dent has little impact to the pressure carrying capacity of the pipe.

Predicting Annual Heating Demand under Sensitivity Analysis

2013 ◽  
Vol 330 ◽  
pp. 911-915 ◽  
Author(s):  
Vladimír Geletka ◽  
Anna Sedláková
Keyword(s):  
Sensitivity Analysis ◽  
Performance Feedback ◽  
Initial Phase ◽  
Architectural Design ◽  
Building Design ◽  
Stochastic Approach ◽  
Energy Performance ◽  
Simulation Based ◽  
Input Parameters ◽  
The Impact

The quality of most buildings may be affected during the initial phase of architectural design. It is therefore to optimize input parameters, which significantly influence energy efficiency. In principle it is possible to speak of a deterministic approach, which consider the input parameters to be fixed or a stochastic approach, which takes a wider set of input parameters into account. A single-storey house is evaluated in terms of energy performance in the initial phase of building design, where input parameters are changed in order to determine a correlation coefficient. The methodology is based on a sensitivity analysis (SA) and MonteCarlo simulation based on a stochastic random selection. Regression (RA) were written to express the impact architectural design has on energy performance. Feedback from the regression model estimates annual heating demand of single storey house.

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