136 research outputs found
Surface EMG-Based Inter-Session/Inter-Subject Gesture Recognition by Leveraging Lightweight All-ConvNet and Transfer Learning
Gesture recognition using low-resolution instantaneous HD-sEMG images opens
up new avenues for the development of more fluid and natural muscle-computer
interfaces. However, the data variability between inter-session and
inter-subject scenarios presents a great challenge. The existing approaches
employed very large and complex deep ConvNet or 2SRNN-based domain adaptation
methods to approximate the distribution shift caused by these inter-session and
inter-subject data variability. Hence, these methods also require learning over
millions of training parameters and a large pre-trained and target domain
dataset in both the pre-training and adaptation stages. As a result, it makes
high-end resource-bounded and computationally very expensive for deployment in
real-time applications. To overcome this problem, we propose a lightweight
All-ConvNet+TL model that leverages lightweight All-ConvNet and transfer
learning (TL) for the enhancement of inter-session and inter-subject gesture
recognition performance. The All-ConvNet+TL model consists solely of
convolutional layers, a simple yet efficient framework for learning invariant
and discriminative representations to address the distribution shifts caused by
inter-session and inter-subject data variability. Experiments on four datasets
demonstrate that our proposed methods outperform the most complex existing
approaches by a large margin and achieve state-of-the-art results on
inter-session and inter-subject scenarios and perform on par or competitively
on intra-session gesture recognition. These performance gaps increase even more
when a tiny amount (e.g., a single trial) of data is available on the target
domain for adaptation. These outstanding experimental results provide evidence
that the current state-of-the-art models may be overparameterized for
sEMG-based inter-session and inter-subject gesture recognition tasks
Modélisation et simulation de la dynamique de la matière organique dissoute en milieu fluvial
Critique de la politique de la reconnaissance de Charles Taylor
Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal
Estimating underwater light regime under spatially heterogeneous sea ice in the Arctic
Abstract: The vertical diffuse attenuation coefficient for downward plane irradiance (Kd
) is an apparent optical property commonly used in primary production models to propagate incident solar radiation in the water column. In open water, estimating Kd is relatively straightforward when a vertical profile of measurements of downward irradiance, Ed, is available. In the Arctic, the ice pack is characterized by a complex mosaic composed of sea ice with snow, ridges, melt ponds, and leads. Due to the resulting spatially heterogeneous light field in the top meters of the water column, it is difficult to measure at single-point locations meaningful Kd values that allow predicting average irradiance at any depth. The main objective of this work is to propose a new method to estimate average irradiance over large spatially heterogeneous area as it would be seen by drifting phytoplankton. Using both in situ data and 3D Monte Carlo numerical simulations of radiative transfer, we show that (1) the large-area average vertical profile of downward irradiance, Ed(z), under heterogeneous sea ice cover can be represented by a single-term exponential function and (2) the vertical attenuation coefficient for upward radiance (KLu), which is up to two times less influenced by a heterogeneous incident light field than Kd in the vicinity of a melt pond, can be used as a proxy to estimate Ed(z) in the water column
Spectral signature of suspended fine particulate material on light absorption properties of CDOM
Catchment tracers reveal discharge, recharge and sources of groundwater-borne pollutants in a novel lake modelling approach
Groundwater-borne contaminants such as nutrients, dissolved organic carbon
(DOC), coloured dissolved organic matter (CDOM) and pesticides can have an
impact the biological quality of lakes. The sources of pollutants can,
however, be difficult to identify due to high heterogeneity in groundwater
flow patterns. This study presents a novel approach for fast hydrological
surveys of small groundwater-fed lakes using multiple groundwater-borne
tracers. Water samples were collected from the lake and temporary groundwater
wells, installed every 50 m within a distance of 5–45 m to
the shore, were analysed for tracer concentrations of CDOM, DOC, total
dissolved nitrogen (TDN, groundwater only), total nitrogen (TN, lake only),
total dissolved phosphorus (TDP, groundwater only), total phosphorus (TP,
lake only), δ18O ∕ δ16O isotope ratios
and fluorescent dissolved organic matter (FDOM) components derived from
parallel factor analysis (PARAFAC). The isolation of groundwater recharge
areas was based on δ18O measurements and areas with a high
groundwater recharge rate were identified using a microbially influenced FDOM
component. Groundwater discharge sites and the fractions of water delivered
from the individual sites were isolated with the Community Assembly via Trait
Selection model (CATS). The CATS model utilized tracer measurements of TDP,
TDN, DOC and CDOM from the groundwater samples and related these to the
tracer measurements of TN, TP, DOC and CDOM in the lake. A direct comparison
between the lake and the inflowing groundwater was possible as degradation
rates of the tracers in the lake were taken into account and related to
a range of water retention times (WRTs) of the lake (0.25–3.5 years in
0.25-year increments). These estimations showed that WRTs above 2 years
required a higher tracer concentration of inflowing water than found in any
of the groundwater wells around the lake. From the estimations of inflowing
tracer concentration, the CATS model isolated groundwater discharge sites
located mainly in the eastern part of the lake with a single site in the
southern part. Observations from the eastern part of the lake revealed an
impermeable clay layer that promotes discharge during heavy precipitation
events, which would otherwise be difficult to identify using traditional
hydrological methods. In comparison to the lake concentrations, high tracer
concentrations in the southern part showed that only a smaller fraction of
water could originate from this area, thereby confirming the model results.
A Euclidean cluster analysis of δ18O isotopes identified
recharge sites corresponding to areas adjacent to drainage channels, and
a cluster analysis of the microbially influenced FDOM component C4 further
identified five sites that showed a tendency towards high groundwater
recharge rate. In conclusion, it was found that this methodology can be
applied to smaller lakes within a short time frame, providing useful
information regarding the WRT of the lake and more importantly the
groundwater recharge and discharge sites around the lake. Thus, it is a tool
for specific management of the catchment
Eutrophication Leads to Accumulation of Recalcitrant Autochthonous Organic Matter in Coastal Environment
Peer reviewe
Global distribution of dissolved organic matter along the aquatic continuum: Across rivers, lakes and oceans
Goal-Directed Task Analysis for Situation Awareness Requirements During Ship Docking in Compulsory Pilotage Area
In this paper we present the results from a Goal Directed Task Anal-ysis (GDTA), a variant of cognitive task analysis techniques, to extract the op-erator’s situation awareness requirements. This analysis is done with 8 pilots from the Mid Saint-Laurence Pilots Corporation (CPSLC) on a ship docking scenario in a compulsory pilotage area. These findings are used to develop a tool to measure the pilot’s situation awareness during the maneuver using SAGAT questionnaire
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