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Antoni Grau

Publications and source records attributed to Antoni Grau.

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LDGCN: An Edge-End Lightweight Dual GCN Based on Single-Channel EEG for Driver Drowsiness Monitoring

Driver drowsiness electroencephalography (EEG) signal monitoring can timely alert drivers of their drowsiness status, thereby reducing the probability of traffic accidents. Graph convolutional networks (GCNs) have shown significant advancements in processing the non-stationary, time-varying, and non-Euclidean nature of EEG signals. However, the existing single-channel EEG adjacency graph construction process lacks interpretability, which hinders the ability of GCNs to effectively extract adjacency graph features, thus affecting the performance of drowsiness monitoring. To address this issue, we propose an edge-end lightweight dual graph convolutional network (LDGCN). Specifically, we are the first to incorporate neurophysiological knowledge to design a Baseline Drowsiness Status Adjacency Graph (BDSAG), which characterizes driver drowsiness status. Additionally, to express more features within limited EEG data, we introduce the Augmented Graph-level Module (AGM). This module captures global and local information at the graph level, ensuring that BDSAG features remain intact while enhancing effective feature expression capability. Furthermore, to deploy our method on the fourth-generation Raspberry Pi, we utilize Adaptive Pruning Optimization (APO) on both channels and neurons, reducing inference latency by almost half. Experiments on benchmark datasets demonstrate that LDGCN offers the best trade-off between monitoring performance and hardware resource utilization compared to existing state-of-the-art algorithms. All our source code can be found at https://github.com/BryantDom/Driver-Drowsiness-Monitoring.

eess.SP

Benthic inputs as predictors of seagrass (Posidonia oceanica) fish farm-induced decline

Fish farms represent a growing source of disturbance to shallow benthic ecosystems like seagrass meadows. Despite some existing insights on the mechanisms underlying decline, efficient tools to quantitatively predict the response of benthic communities to fish farm effluents have not yet been developed. We explored relationships of fish farm organic and nutrient input rates to the sediments with population dynamics of the key seagrass species (Posidonia oceanica) in deep meadows growing around four Mediterranean Sea bream and Sea bass fish farms. We performed 2 annual shoot censuses on permanent plots at increasing distance from cages. Before each census we measured sedimentation rates adjacent to the plots using benthic sediment traps. High shoot mortality rates were recorded near the cages, up to 20 times greater than at control sites. Recruitment rates remained similar to undisturbed meadows and could not compensate mortality, leading to rapid seagrass decline within the first 100 meters from cages. Seagrass mortality increased with total (R2= 0.47, p< 0.0002), organic matter (R2= 0.36, p= 0.001), nitrogen (R2= 0.34, p= 0.002) and phosphorus (R2= 0.58, p< 3 x 10-5) sedimentation rates. P. oceanica decline accelerated above a phosphorus loading threshold of 50 mg m-2 day-1. Benthic sedimentation rates seem a powerful predictor of seagrass mortality from fish farming, integrating local hydrodynamics, waste effluents variability and several environmental mechanisms, fuelled by organic inputs and leading to seagrass loss. Coupling direct measurements of benthic sedimentation rates with dynamics of key species is proposed as an efficient way to predict and minimize fish farm impacts to benthic communities.

q-bio.QM