Publications by authors named "J H van der Vegt"
State-of-the-art computational methods combined with common idealized structural models provide an incomplete understanding of experimental observations on real nanostructures, since manufacturing introduces unavoidable deviations from the design. We propose to close this knowledge gap by using the real structure of a manufactured nanostructure as input in computations to obtain a realistic comparison with measurements on the same nanostructure. We demonstrate this approach on the structure of a real inverse woodpile photonic bandgap crystal made from silicon, as previously obtained by synchrotron X-ray imaging.
View Article and Find Full Text PDFArticle Synopsis
- The authors introduce a method that uses unsupervised machine learning to improve the classification of wave confinement dimensionality, building on their previous work.
- They apply k-means++ and a new model-based algorithm to analyze 3D superlattices of cavities in a photonic band gap crystal and compare the results with direct scaling methods.
- The study finds that using direct scaling first to identify dimensionality, followed by their model-based clustering, yields the most accurate results.
Functional defects in periodic media confine waves-acoustic, electromagnetic, electronic, spin, etc.-in various dimensions, depending on the structure of the defect. While defects are usually modeled by a superlattice with a typical band-structure representation of energy levels, determining the confinement associated with a given band is highly nontrivial and no analytical method is known to date.
View Article and Find Full Text PDFObjective: The spread of the COVID-19 virus has caused an unforeseen strain on the healthcare system and particularly on healthcare workers (HCW). In this study, 1 year after the COVID-19 pandemic began, we used photovoice, a visual photographic approach, to understand HCW needs, concerns and resilience and to determine improvement strategies aligned with the HCW-described challenges.
Methods: Using a qualitative design, HCW were recruited from a single Western Canadian hospital, voluntarily submitting a photographic image and narrative that depicts their experiences.
Objective: To describe three cases with neurological symptoms after SARS-CoV-2 vaccination.
Methods: A case series followed by a review of the literature, describing hypotheses on how neurological symptoms might develop after vaccination.
Results: The different temporal relationship between the onset or worsening of different neurological symptoms suggests different pathophysiological mechanisms.