Accuracy Assessment of Thermoacoustic Instability Models Using Binary Classification

Hoeijmakers, Maarten; Arteaga, Inés López; Kornilov, Viktor; Nijmeijer, Henk; Goey, de Lph Philip

doi:10.1260/1756-8277.5.3.201

Cited by 7 publications

(5 citation statements)

References 18 publications

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“…DiFilippo [12] presented an assessment method that can be applied on SPECT and PET phantom images utilizing binary classification. Hoeijmakers [13] proposed an accuracy assessment of thermoacoustic instability models that involved binary classification.…”

Section: Mathematical Modeling Of Data Quality Assessmentmentioning

confidence: 99%

Method for Data Quality Assessment of Synthetic Industrial Data

Iantovics

Enăchescu

2022

Sensors

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Sometimes it is difficult, or even impossible, to acquire real data from sensors and machines that must be used in research. Such examples are the modern industrial platforms that frequently are reticent to share data. In such situations, the only option is to work with synthetic data obtained by simulation. Regarding simulated data, a limitation could consist in the fact that the data are not appropriate for research, based on poor quality or limited quantity. In such cases, the design of algorithms that are tested on that data does not give credible results. For avoiding such situations, we consider that mathematically grounded data-quality assessments should be designed according to the specific type of problem that must be solved. In this paper, we approach a multivariate type of prediction whose results finally can be used for binary classification. We propose the use of a mathematically grounded data-quality assessment, which includes, among other things, the analysis of predictive power of independent variables used for prediction. We present the assumptions that should be passed by the synthetic data. Different threshold values are established by a human assessor. In the case of research data, if all the assumptions pass, then we can consider that the data are appropriate for research and can be applied by even using other methods for solving the same type of problem. The applied method finally delivers a classification table on which can be applied any indicators of performed classification quality, such as sensitivity, specificity, accuracy, F1 score, area under curve (AUC), receiver operating characteristics (ROC), true skill statistics (TSS) and Kappa coefficient. These indicators’ values offer the possibility of comparison of the results obtained by applying the considered method with results of any other method applied for solving the same type of problem. For evaluation and validation purposes, we performed an experimental case study on a novel synthetic dataset provided by the well-known UCI data repository.

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Section: Mathematical Modeling Of Data Quality Assessmentmentioning

confidence: 99%

Method for Data Quality Assessment of Synthetic Industrial Data

Iantovics

Enăchescu

2022

Sensors

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“…As a consequence, each mode actually belongs to an uncertain region in the complex plane, as illustrated in figure 2(a). It is quantified by a risk factor defined as the probability for a mode to be unstable: this is a novel notion which renews the classical bi-modal stable/unstable view in thermoacoustics (Hoeijmakers et al 2013). Even though our objective is to apply UQ in full 3-D Helmholtz solvers, it is first applied here using the ATACAMAC methodology (Parmentier et al 2012;Bauerheim et al 2014d) because (i) it is much more cost effective while retaining most of the characteristics of Helmholtz solvers, and (ii) partially analytical results are available for comparison (Bauerheim et al 2014d).…”

Section: Introductionmentioning

confidence: 98%

Symmetry breaking of azimuthal thermoacoustic modes: the UQ perspective

et al. 2016

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Since its introduction in the late 19th century, symmetry breaking has been found to play a crucial role in physics. In particular, it appears as one key phenomenon controlling hydrodynamic and acoustic instabilities in problems with rotational symmetries. A previous paper investigated its desired potential application to the control of circumferential thermoacoustic modes in one annular cavity coupled with multiple flames (Bauerheim et al., J. Fluid Mech., vol. 760, 2014, pp. 431–465). The present paper focuses on a similar problem when symmetry breaking appears unintentionally, for example when uncertainties due to tolerances are taken into account. It yields a large uncertainty quantification (UQ) problem containing numerous uncertain parameters. To tackle this well-known ‘curse of dimensionality’, a novel UQ methodology is used. It relies on the active subspace approach to construct a reduced set of input variables. This strategy is applied on two annular cavities coupled by 19 flames to determine its modal risk factor, i.e. the probability of an azimuthal acoustic mode being unstable. Since each flame is modelled by two uncertain parameters, it leads to a large UQ problem involving 38 parameters. An acoustic network model is then derived, which yields a nonlinear dispersion relation for azimuthal modes. This nonlinear problem, subject to bifurcations, is solved quasi-analytically. Results show that the dimension of the probabilistic problem can be drastically reduced, from 38 uncertain parameters to only 3. Moreover, it is found that the three active variables are related to physical quantities, which unveils underlying phenomena controlling the stability of the two coupled cavities. The first active variable is associated with a coupling strength controlling the bifurcation of the system, while the two others correspond to a symmetry-breaking effect induced by the uncertainties. Thus, an additional destabilization effect appear caused by the non-uniform pattern of the uncertainty distribution, which breaks the initial rotating symmetry of the annular cavities. Finally, the active subspace is exploited by fitting the response surface with polynomials (linear, quadratic and cubic). By comparing accuracy and cost, results prove that 5 % error can be achieved with only 30 simulations on the reduced space, whereas 2000 are required on the complete initial space. It exemplifies that this novel UQ technique can accurately predict the risk factor of an annular configuration at low cost as well as unveil key parameters controlling the stability.

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“…This approach has been successfully applied in numerous studies before. 7,25,26 However, the conventional modeling approach does not provide a good overview of conditions and guidelines for designing the upstream and downstream sides of the flame such that the system would be stable. The crux is in the absence of specific parameters or criteria to determine the system stability and lack of tools (rules) on how to manipulate the system design as it is done in microwave theory.…”

Section: Introductionmentioning

confidence: 99%

Stability criteria of two-port networks, application to thermo-acoustic systems

Kojourimanesh

Kornilov

Arteaga

et al. 2022

International Journal of Spray and Combustion Dynamics

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System theory methods are developed and applied to introduce a new analysis methodology based on the stability criteria of active two-ports, to the problem of thermo-acoustic instability in a combustion appliance. The analogy between thermo-acoustics of combustion and small-signal operation of microwave amplifiers is utilized. Notions of unconditional and conditional stabilities of an (active) two-port, representing a burner with flame, are introduced and analyzed. Unconditional stability of two-port means the absence of autonomous oscillation at any embedding of the given two-port by any passive network at the system's upstream (source) and downstream (load) sides. It has been shown that for velocity-sensitive compact burners in the limit of zero Mach number, the criteria of unconditional stability cannot be fulfilled. The analysis is performed in the spirit of a known criterion in microwave network theory, the so-called Edwards-Sinsky's criterion. Therefore, two methods have been applied to elucidate the necessary and sufficient conditions of a linear active two-port system to be conditionally stable. The first method is a new algebraic technique to prove and derive the conditional and unconditional stability criteria, and the second method is based on certain properties of Mobius (bilinear) transformations for combinations of reflection coefficients and scattering matrix of (active) two-ports. The developed framework allows formulating design requirements for the stabilization of operation of a combustion appliance via purposeful modifications of either the burner properties or/and of its acoustic embeddings. The analytical derivations have been examined in a case study to show the power of the methodology in the thermo-acoustics system application.

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Accuracy Assessment of Thermoacoustic Instability Models Using Binary Classification

Cited by 7 publications

References 18 publications

Method for Data Quality Assessment of Synthetic Industrial Data

Method for Data Quality Assessment of Synthetic Industrial Data

Symmetry breaking of azimuthal thermoacoustic modes: the UQ perspective

Stability criteria of two-port networks, application to thermo-acoustic systems

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