Assessment of Vigilance Level during Work: Fitting a Hidden Markov Model to Heart Rate Variability

This study aimed to enhance the real-time performance and accuracy of vigilance assessment by developing a hidden Markov model (HMM). Electrocardiogram (ECG) signals were collected and processed to remove noise and baseline drift. A group of 20 volunteers participated in the study. Their heart rate variability (HRV) was measured to train...

Deep Bayesian survival analysis of rail useful lifetime

Reliable estimation of rail useful lifetime can provide valuable information for predictive maintenance in railway systems. However, in most cases, lifetime data is incomplete because not all pieces of rail experience failure by the end of the study horizon, a problem known as censoring. Ignoring or otherwise mistreating the censored cases...

Rail break prediction and cause analysis using imbalanced in-service train data

Timely detection and identification of rail breaks are crucial for safety and reliability of railway networks. This paper proposes a new deep learning-based approach using the daily monitoring data from in-service trains. A time-series generative adversarial network (TimeGAN) is employed to mitigate the problem of data imbalance and preserve the...

River, tide and morphology interaction in a macro-tidal estuary with active morphological evolutions

Understanding tidal dynamics in estuaries is essential for tidal predictions and assessments of sediment transport and associated morphological changes. Most studies on river-tide interaction ignored the influences of morphological evolutions under natural conditions such as the seasonal and interannual variations of river discharge. This...

Morphodynamic modeling the impact of large-scale embankment on the large bar in a convergent estuary

Many alluvial estuaries worldwide include an inside bar system, a large sediment deposit deeply stretched into the estuary. A good example of such a system is the large sediment deposit in the Qiantang Estuary, China. Its length and height reach 130 km and 10 m, respectively. Bathymetrical comparison reveals that the large bar has moved seaward...