scholarly journals Design of experiments: a statistical tool for PIV uncertainty quantification

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Sagar Adatrao ◽  
Andrea Sciacchitano ◽  
Simone van der Velden ◽  
Mark-Jan van der Meulen ◽  
Marc Cruellas Bordes
Keyword(s):  
Design Of Experiments ◽  
Uncertainty Quantification ◽  
Interrogation Window ◽  
Window Size ◽  
Measured Quantity ◽  
Test Case ◽  
Statistical Tool ◽  
Total Uncertainty ◽  
Systematic Uncertainties ◽  
The Individual

A statistical tool called Design of Experiments (DOE) is introduced for uncertainty quantification in particle image velocimetry (PIV). DOE allows to quantify the total uncertainty as well as the systematic uncertainties arising from various experimental factors. The approach is based on measuring a quantity (e.g. time-averaged velocity from PIV) several times by varying the levels of the experimental factors which are known to affect the value of the measured quantity. In this way, using Analysis of Variances (ANOVA), the total variance in the measured quantity can be computed and hence the total uncertainty. Moreover, the analysis provides the individual variances for each of the experimental factors leading to the estimation of the systematic uncertainties from each factor and their contribution to the total uncertainty. The methodology is assessed for an experimental test case of the flow at the outlet of a ducted Boundary Layer Ingesting (BLI) propulsor to quantify the total uncertainty in time-averaged velocity from stereoscopic PIV measurements as well as the constituent systematic uncertainties due to the experimental factors, namely, camera aperture, inter-frame time separation, interrogation window size and stereoscopic camera angle.

Design and Optimization of Multi-Stage Centrifugal Compressors With Uncertainty Quantification of Off Design Performance

2017 ◽  
Author(s):  
A. Romei ◽  
R. Maffulli ◽  
C. Garcia Sanchez ◽  
S. Lavagnoli
Keyword(s):  
Uncertainty Quantification ◽  
Oil And Gas ◽  
Low Cost ◽  
Design Procedure ◽  
Design Tool ◽  
Test Case ◽  
Centrifugal Compressors ◽  
Design Performance ◽  
Leading Role ◽  
Multi Stage

The use of multi-stage centrifugal compressors carries out a leading role in oil and gas process applications. Green operation and market competitiveness require the use of low-cost reliable compression units with high efficiencies and wide operating range. A methodology is presented for the design optimization of multi-stage centrifugal compressors with prediction of the compressor map and estimation of the uncertainty limits. A one-dimensional (1D) design tool has been developed that automatically generates a multi-stage radial compressor satisfying the target machine requirements based on a few input parameters. The compressor performance map is then assessed using the method proposed by Casey-Robinson [1], and the approach developed by Al-Busaidi-Pilidis [2]. The off-design performance method relies on empirical correlations calibrated on the performance maps of many single-stage centrifugal compressors. An uncertainty quantification study on the predicted performance maps was conducted using Monte Carlo method (MCM) and generalized Polynomial Chaos Expansion (gPCE). Finally, the design procedure has been coupled to an in-house optimizer based on evolutionary algorithms. The complete design procedure has been applied to a multi-stage industrial compressor test case. A multi-objective optimization of a multi-stage industrial compressor has been performed targeting maximum compressor efficiency and flow range. The results of the optimization show the existence of optimum compressor architectures and how the Pareto fronts evolve depending on the number of stages and shafts.

scholarly journals Swelling Clay Parameters Investigation Using Design of Experiments (A Case Study)

2021 ◽  
Author(s):  
Yacine Berrah ◽  
Serhane Brahmi ◽  
Nouar Charef ◽  
Abderrahman Boumezbeur
Keyword(s):  
Design Of Experiments ◽  
Swelling Pressure ◽  
Unit Weight ◽  
Factor Screening ◽  
Statistical Tool ◽  
Factors Affecting ◽  
Screening Design ◽  
Expansion Behavior ◽  
Prone Area ◽  
Parametric Effects

The present paper aims to investigate geotechnical parametric effects on the expansion behavior of clayey soils in Tebessa province northeast of Algeria using the Design Of Experiments (DOE) methodology. It has been used as powerful tools based on physical and mechanical properties, data results obtained within laboratory soil mechanics testing. This statistical tool methodology presents the factor screening design to determine the effect of different parameters such as dry unit weight, saturation degree, water content, plasticity index, etc., on the swelling pressure parameter which can be used as expansion behavior of clay indicator. All data previously collected in the studied prone area allows the ability of detailed analysis using design of experiment and parametric optimization process with response surface methodology (RSM). Each variable that present effects on swelling pressure is also discussed. Besides, the obtained models and equations related the factors affecting the expansion process have been determined. At the output process; the response desirability of the screening design methodology can be optimized by maximization or minimization of the optimal values affecting the swelling behavior. This process allows us to find the best describing models, whereas output results may be compared to empirical laboratory tests results to assess the RSM models.

Emmanuel Levinas and the Problem of Meaningless Suffering: the Holocaust as a Test Case

Horizons ◽  
1999 ◽  
Vol 26 (1) ◽  
pp. 73-84
Author(s):  
Marie L. Baird
Keyword(s):  
Emmanuel Levinas ◽  
Human Life ◽  
Christian Theology ◽  
Test Case ◽  
Christian Spirituality ◽  
Johann Baptist Metz ◽  
The Holocaust ◽  
The Face ◽  
The Subject ◽  
The Individual

AbstractJohann Baptist Metz has exhorted Christian theologians to discard “system concepts” in favor of “subject concepts” in their theologizing. This revisioning of Christian theology recovers the primacy of the uniqueness and irreplaceability of the individual from totalizing doctrinal formulations and systems that function, for Metz, without reference to the subject. In short, a revisionist Christian theology in light of the Holocaust recovers the preeminence of the inviolability of individual human life.How can such a revisioning be accomplished in the realm of Christian spirituality? This article will utilize the thought of Emmanuel Levinas to assert the primacy of ethics as “first philosophy” replacing ontology, and by implication the ontological foundations undergirding Christian spirituality, with the ethical relation. Such a relation is the basis for a new Christian spirituality that posits the primacy of merciful and compasionate action in the face of conditions of life in extremity.

Single Pixel Evaluation of Microchannel Flows

2005 ◽  
Author(s):  
Steve Wereley ◽  
Carl Meinhart ◽  
Lichuan Gui ◽  
Derek Tretheway ◽  
Arjun Sud
Keyword(s):  
Correlation Analysis ◽  
Particle Concentration ◽  
Interrogation Window ◽  
Window Size ◽  
Bias Error ◽  
Zero Bias ◽  
Effective Particle ◽  
The Interrogation Window Size ◽  
Error Behavior ◽  
Single Pixel

Recently a new μPIV interrogation algorithm has been proposed in which the interrogation window size is reduced to a single pixel. Such small interrogation window sizes are possible using correlation averaging to increase the effective particle concentration to levels required for correlation analysis to succeed. The random error exhibits the expected behavior of decreasing roughly in proportion to N−1/2 while the bias error exhibits unexpected peak-locking behavior with zero bias error at integer and half integer pixel displacements and maximal errors at one-quarter and three-quarter pixel displacements. Accompanying experiments show the potential of this technique but have not yet been sufficiently refined to confirm this unexpected bias error behavior.

scholarly journals Impact of robot antenna calibration on dual-frequency smartphone-based high-accuracy positioning: a case study using the Huawei Mate20X

GPS Solutions ◽  
2020 ◽  
Vol 25 (1) ◽  
Author(s):  
Francesco Darugna ◽  
Jannes B. Wübbena ◽  
Gerhard Wübbena ◽  
Martin Schmitz ◽  
Steffen Schön ◽  
...  
Keyword(s):  
Ambiguity Resolution ◽  
High Accuracy ◽  
Global Navigation Satellite Systems ◽  
Test Case ◽  
Dual Frequency ◽  
Main Site ◽  
Satellite Systems ◽  
The Individual ◽  
The Impact ◽  
Antenna Calibration

Abstract The access to Android-based Global Navigation Satellite Systems (GNSS) raw measurements has become a strong motivation to investigate the feasibility of smartphone-based positioning. Since the beginning of this research, the smartphone GNSS antenna has been recognized as one of the main limitations. Besides multipath (MP), the radiation pattern of the antenna is the main site-dependent error source of GNSS observations. An absolute antenna calibration has been performed for the dual-frequency Huawei Mate20X. Antenna phase center offset (PCO) and variations (PCV) have been estimated to correct for antenna impact on the L1 and L5 phase observations. Accordingly, we show the relevance of considering the individual PCO and PCV for the two frequencies. The PCV patterns indicate absolute values up to 2 cm and 4 cm for L1 and L5, respectively. The impact of antenna corrections has been assessed in different multipath environments using a high-accuracy positioning algorithm employing an undifferenced observation model and applying ambiguity resolution. Successful ambiguity resolution is shown for a smartphone placed in a low multipath environment on the ground of a soccer field. For a rooftop open-sky test case with large multipath, ambiguity resolution was successful in 19 out of 35 data sets. Overall, the antenna calibration is demonstrated being an asset for smartphone-based positioning with ambiguity resolution, showing cm-level 2D root mean square error (RMSE).

Hesiod and the Visual Arts

2018 ◽  
Author(s):  
H. A. Shapiro
Keyword(s):  
Visual Arts ◽  
Archaic Period ◽  
Test Case ◽  
Complex Relationship ◽  
Vase Painting ◽  
Visual Artists ◽  
Text And Image ◽  
Major Work ◽  
The Individual ◽  
Relationship Of

This chapter explores the influence of Hesiod’s Theogony on Greek visual artists of the archaic period (ca. 700–480 bce). Since dozens of divinities and heroes mentioned in the poem appear in sculpture and (more often) vase painting and cannot be systematically treated, one major work with strong Hesiodic associations is examined as a test case. The Attic black-figure dinos signed by the painter Sophilos and dated ca. 580 bce includes more than thirty gods and goddesses participating in the wedding of Peleus and Thetis, future parents of Achilles. All of these can be found in the Theogony, and the poem can be a helpful guide to understanding how the individual figures are placed in the procession. The unique depiction of Okeanos on the dinos illustrates especially well the complex relationship of text and image.

Uncertainty Quantification and Stochastic Variations of Renewable Fuels

2015 ◽  
Author(s):  
F. Montomoli ◽  
M. Insinna ◽  
A. Cappelletti ◽  
S. Salvadori
Keyword(s):  
Standard Deviation ◽  
Temperature Distribution ◽  
Combustion Chamber ◽  
Uncertainty Quantification ◽  
Mean Value ◽  
Maximum Temperature ◽  
Test Case ◽  
Renewable Fuels ◽  
Stochastic Variation ◽  
The Stability

Renewable fuels have been successfully used in gas turbine combustion chambers and the layout of the chamber does not require major interventions if the composition is known. However, the variation in the composition in renewable fuels is higher than in fossil ones and it is stochastic. In principle, this variation affects the stability of the combustion, the emissions and the temperature distribution. The combustion chamber tested in this work has been designed to reproduce the temperature distribution of MT1 test case and modelled using reactive CFD simulations. The fuel is an ideal natural gas with a random mix of methane and hydrogen. In order to account the stochastic variation of the fuel composition, a probabilistic analysis is carried out with two sampling methods: a Monte Carlo simulation with meta-models and a Probabilistic Collocation Method. The two methodologies show similar results in terms of mean value and standard deviation. The paper proves that is possible to predict the mean value of temperature and emissions in a modern chamber and their associated standard deviation by applying an uncertainty quantification methodology. One of the major drawbacks of the composition change is the maximum temperature variation at the exit that can reduce the life of the downstream turbine. The variation in the emissions seems less important and all the major differences in the composition are mixed out before the combustion chamber exit.

scholarly journals Exploratory studies into seasonal flow forecasting potential for large lakes

2018 ◽  
Vol 22 (1) ◽  
pp. 127-141 ◽  
Author(s):  
Kevin Sene ◽  
Wlodek Tych ◽  
Keith Beven
Keyword(s):  
Water Balance ◽  
Lake Victoria ◽  
Spatial Scales ◽  
Data Availability ◽  
Climate Indices ◽  
Test Case ◽  
Large Lakes ◽  
Analytical Approximations ◽  
Seasonal Flow ◽  
The Individual

Abstract. In seasonal flow forecasting applications, one factor which can help predictability is a significant hydrological response time between rainfall and flows. On account of storage influences, large lakes therefore provide a useful test case although, due to the spatial scales involved, there are a number of modelling challenges related to data availability and understanding the individual components in the water balance. Here some possible model structures are investigated using a range of stochastic regression and transfer function techniques with additional insights gained from simple analytical approximations. The methods were evaluated using records for two of the largest lakes in the world – Lake Malawi and Lake Victoria – with forecast skill demonstrated several months ahead using water balance models formulated in terms of net inflows. In both cases slight improvements were obtained for lead times up to 4–5 months from including climate indices in the data assimilation component. The paper concludes with a discussion of the relevance of the results to operational flow forecasting systems for other large lakes.

scholarly journals The ISAR Instrument Uncertainty Model

2016 ◽  
Vol 33 (11) ◽  
pp. 2415-2433 ◽  
Author(s):  
Werenfrid Wimmer ◽  
Ian S. Robinson
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Sea Surface ◽  
Retrieval Algorithm ◽  
Total Uncertainty ◽  
Sources Of Uncertainty ◽  
Uncertainty Model ◽  
The Individual ◽  
Along Track ◽  
Instrument Accuracy

AbstractMeasurements of sea surface temperature at the skin interface () made by an Infrared Sea Surface Temperature Autonomous Radiometer (ISAR) have been used for a number of years to validate satellite sea surface temperature (SST), especially high-accuracy observations such as made by the Advanced Along-Track Scanning Radiometer (AATSR). The ISAR instrument accuracy for measuring is ±0.1 K (Donlon et al.), but to satisfy Quality Assurance Framework for Earth Observation (QA4EO) principles and metrological standards (Joint Committee for Guides in Metrology), an uncertainty model is required. To develop the ISAR uncertainty model, all sources of uncertainty in the instrument are analyzed and an uncertainty value is assigned to each component. Finally, the individual uncertainty components are propagated through the ISAR retrieval algorithm to estimate a total uncertainty for each measurement. The resulting ISAR uncertainty model applied to a 12-yr archive of measurements from the Bay of Biscay shows that 77.6% of the data are expected to be within ±0.1 K and a further 17.2% are within 0.2 K.

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