Uncertainty quantification in the assessment of human exposure to pulsed or multi-frequency fields

Physics in medicine and biology · 2023 · Unclear · Insufficient evidence

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Study snapshot

PublicationPhysics in medicine and biology · 2023

Study typeengineering

Reported directionUnclear

Evidence ratingInsufficient

Abstract

Uncertainty quantification in the assessment of human exposure to pulsed or multi-frequency fields Giaccone L. Uncertainty quantification in the assessment of human exposure to pulsed or multi-frequency fields. Phys Med Biol. 2023 Mar 30. doi: 10.1088/1361-6560/acc924. Abstract Objective: pulsed fields or waveforms with multi-frequency content have to be assessed with suitable methods. This paper deals with the uncertainty quantification associated to these methods. Approach: among all possible approaches, the weighted peak method is widely employed in standards and guidelines, therefore, in this paper, we consider its implementation both in time domain and frequency domain. For the uncertainty quantification the polynomial chaos expansion theory is used. By means of a sensitivity analysis, for several standard waveforms, the parameters with more influence on the exposure index are identified and their sensitivity indices are quantified. The output of the sensitivity analysis is used to set up a parametric analysis with the aim of evaluating the uncertainty propagation of the analyzed methods and, finally, also several measured waveforms generated by a welding gun are tested. Main findings: it is shown that the time domain implementation of the weighted peak method provides results in agreement with the basilar mechanisms of electromagnetic induction and electrostimulation. On the opposite, the WPM in frequency domain is found to be too sensitive to parameters that should not influence the exposure index because its weight function includes sharp variations of the phase centered on real zeros and poles. To overcome this issue, a new definition for the phase of the weight function in frequency domain is proposed. Significance: it is shown that the time domain implementation of the weighted peak method is the more accurate and precise. The standard WPM in frequency domain has some issues that can be avoided with the proposed modification of the phase definition of the weight function. Finally, all the codes used in this paper are hosted on a GitHub and can be freely accessed at github.com. pubmed.ncbi.nlm.nih.gov

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Study typeengineering

Effect directionunclear

PopulationNot supplied

Sample sizeNot supplied

ExposureNot supplied

Evidence strengthInsufficientConfidence: 74% · Peer reviewed: unknown

Main findings

Using polynomial chaos expansion and sensitivity/parametric analyses on standard waveforms and measured waveforms from a welding gun, the time-domain implementation of the weighted peak method (WPM) produced results described as consistent with electromagnetic induction/electrostimulation mechanisms. The frequency-domain WPM was reported to be overly sensitive to parameters that should not influence the exposure index due to sharp phase variations in the weight function; a modified phase definition was proposed to address this.

Outcomes measured

Uncertainty quantification for exposure assessment methods (weighted peak method) for pulsed or multi-frequency fields
Sensitivity of exposure index to waveform/weight-function parameters
Comparison of time-domain vs frequency-domain implementations of weighted peak method

View raw extracted JSON

{
  "study_type": "engineering",
  "exposure": {
    "band": null,
    "source": "occupational",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "Uncertainty quantification for exposure assessment methods (weighted peak method) for pulsed or multi-frequency fields",
    "Sensitivity of exposure index to waveform/weight-function parameters",
    "Comparison of time-domain vs frequency-domain implementations of weighted peak method"
  ],
  "main_findings": "Using polynomial chaos expansion and sensitivity/parametric analyses on standard waveforms and measured waveforms from a welding gun, the time-domain implementation of the weighted peak method (WPM) produced results described as consistent with electromagnetic induction/electrostimulation mechanisms. The frequency-domain WPM was reported to be overly sensitive to parameters that should not influence the exposure index due to sharp phase variations in the weight function; a modified phase definition was proposed to address this.",
  "effect_direction": "unclear",
  "limitations": [],
  "evidence_strength": "insufficient",
  "confidence": 0.74,
  "peer_reviewed_likely": "unknown",
  "keywords": [
    "uncertainty quantification",
    "human exposure assessment",
    "pulsed fields",
    "multi-frequency fields",
    "weighted peak method",
    "time domain",
    "frequency domain",
    "polynomial chaos expansion",
    "sensitivity analysis",
    "welding gun",
    "electromagnetic induction",
    "electrostimulation"
  ],
  "suggested_hubs": [
    {
      "slug": "occupational-exposure",
      "weight": 0.62,
      "reason": "Measured waveforms generated by a welding gun were tested, suggesting an occupational exposure context."
    }
  ]
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1088/1361-6560/acc924
PubMed: 36996847

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