Combining spatial components and Hilbert transforms to interpret ground-time-domain electromagnetic data

Combining geometry and domain knowledge to interpret hand-drawn diagrams

We present a sketch understanding system for network-like diagrams consisting of symbols linked together. This system employs a novel parser to automatically extract symbols from a continuous stream of pen strokes. The parser uses geometric information to enumerate candidate symbols, and then uses domain knowledge to prune away unlikely candidates. The candidates are classified with a novel, do...

Electromagnetic Field Due to Lightning Strikes to Mountainous Ground

The produced electric and magnetic fields due to lightning strikes to mountainous ground are determined in this paper. For the sake of simplicity a cone-shaped ground with finite conductivity is assumed to represent a natural nonflat ground. By this assumption, we deal with an axillary symmetrical structure so we use the cylindrical 2D-FDTD to save the simulation memory and time, dramatically. ...

Efficacy of Hilbert and Wavelet Transforms for Time-Frequency Analysis

Two independently emerging time-frequency transformations in Civil Engineering, namely, the wavelet transform and empirical mode decomposition with Hilbert transform EMD+HT , are discussed in this study. Their application to a variety of nonstationary and nonlinear signals has achieved mixed results, with some comparative studies casting significant doubt on the wavelet’s suitability for such a...

Combining time DEA scores using a dynamic panel data model

We define a combined DEA score to evaluate efficiency in agricultural research. The production model we propose considers efficiency measurements under variable returns to scale for each year in the period 2012–2017. We postulate a first-order autoregressive process in the presence of covariates, to explain efficiency. Powers of the autocorrelation coefficient estimated assuming a dynamic panel...

Two-dimensional Hilbert Transforms'