22 citations · 34 across the 14 of their papers we have counts for
6 papers · 1 filter
Soft-Output Signal Detection for Cetacean Vocalizations Using Spectral Entropy, K-Means Clustering and the Continuous Wavelet Transform
Marco W. Rademan, Daniel J. Versfeld, Johan A. du Preez
Underwater acoustic monitoring systems record many hours of audio data for marine research, making fast and reliable non-causal signal detection paramount. Such detectors assist in…
Rail break and derailment prediction using Probabilistic Graphical Modelling
Rebecca M. C. Taylor, Johan A. du Preez
Rail breaks are one of the most common causes of derailments internationally. This is no different for the South African Iron Ore line. Many rail breaks occur as a heavy-haul train…
SimLDA: A tool for topic model evaluation
Rebecca M. C. Taylor, Johan A. du Preez
Variational Bayes (VB) applied to latent Dirichlet allocation (LDA) has become the most popular algorithm for aspect modeling. While sufficiently successful in text topic extractio…
A Temporal Extension of Latent Dirichlet Allocation for Unsupervised Acoustic Unit Discovery
Werner van der Merwe, Herman Kamper, Johan du Preez
Latent Dirichlet allocation (LDA) is widely used for unsupervised topic modelling on sets of documents. No temporal information is used in the model. However, there is often a rela…
LDPC codes: tracking non-stationary channel noise using sequential variational Bayesian estimates
J du Toit, J du Preez, R Wolhuter
We present a sequential Bayesian learning method for tracking non-stationary signal-to-noise ratios in LDPC codes using probabilistic graphical models. We represent the LDPC code a…
LDPC codes: comparing cluster graphs to factor graphs
J du Toit, J du Preez, R Wolhuter
We present a comparison study between a cluster and factor graph representation of LDPC codes. In probabilistic graphical models, cluster graphs retain useful dependence between ra…