260 research outputs found
AccEq-DRT: Planning Demand-Responsive Transit to reduce inequality of accessibility
Accessibility measures how well a location is connected to surrounding
opportunities. We focus on accessibility provided by Public Transit (PT). There
is an evident inequality in the distribution of accessibility between city
centers or close to main transportation corridors and suburbs. In the latter,
poor PT service leads to a chronic car-dependency. Demand-Responsive Transit
(DRT) is better suited for low-density areas than conventional fixed-route PT.
However, its potential to tackle accessibility inequality has not yet been
exploited. On the contrary, planning DRT without care to inequality (as in the
methods proposed so far) can further improve the accessibility gap in urban
areas.
To the best of our knowledge this paper is the first to propose a DRT
planning strategy, which we call AccEq-DRT, aimed at reducing accessibility
inequality, while ensuring overall efficiency. To this aim, we combine a graph
representation of conventional PT and a Continuous Approximation (CA) model of
DRT. The two are combined in the same multi-layer graph, on which we compute
accessibility. We then devise a scoring function to estimate the need of each
area for an improvement, appropriately weighting population density and
accessibility. Finally, we provide a bilevel optimization method, where the
upper level is a heuristic to allocate DRT buses, guided by the scoring
function, and the lower level performs traffic assignment. Numerical results in
a simplified model of Montreal show that inequality, measured with the Atkinson
index, is reduced by up to 34\%.
Keywords: DRT Public, Transportation, Accessibility, Continuous
Approximation, Network DesignComment: 15 page
Model Fusion to Enhance the Clinical Acceptability of Long-Term Glucose Predictions
This paper presents the Derivatives Combination Predictor (DCP), a novel
model fusion algorithm for making long-term glucose predictions for diabetic
people. First, using the history of glucose predictions made by several models,
the future glucose variation at a given horizon is predicted. Then, by
accumulating the past predicted variations starting from a known glucose value,
the fused glucose prediction is computed. A new loss function is introduced to
make the DCP model learn to react faster to changes in glucose variations.
The algorithm has been tested on 10 \textit{in-silico} type-1 diabetic
children from the T1DMS software. Three initial predictors have been used: a
Gaussian process regressor, a feed-forward neural network and an extreme
learning machine model. The DCP and two other fusion algorithms have been
evaluated at a prediction horizon of 120 minutes with the root-mean-squared
error of the prediction, the root-mean-squared error of the predicted
variation, and the continuous glucose-error grid analysis.
By making a successful trade-off between prediction accuracy and
predicted-variation accuracy, the DCP, alongside with its specifically designed
loss function, improves the clinical acceptability of the predictions, and
therefore the safety of the model for diabetic people
Robust Line Detection in Historical Church Registers
For being able to automatically acquire information recorded in church registers and other historical scriptures, the text of such documents needs to be segmented prior to automatic reading. Segmentation of old handwritten scriptures is difficult for two main reasons
Study of Short-Term Personalized Glucose Predictive Models on Type-1 Diabetic Children
Research in diabetes, especially when it comes to building data-driven models
to forecast future glucose values, is hindered by the sensitive nature of the
data. Because researchers do not share the same data between studies, progress
is hard to assess. This paper aims at comparing the most promising algorithms
in the field, namely Feedforward Neural Networks (FFNN), Long Short-Term Memory
(LSTM) Recurrent Neural Networks, Extreme Learning Machines (ELM), Support
Vector Regression (SVR) and Gaussian Processes (GP). They are personalized and
trained on a population of 10 virtual children from the Type 1 Diabetes
Metabolic Simulator software to predict future glucose values at a prediction
horizon of 30 minutes. The performances of the models are evaluated using the
Root Mean Squared Error (RMSE) and the Continuous Glucose-Error Grid Analysis
(CG-EGA). While most of the models end up having low RMSE, the GP model with a
Dot-Product kernel (GP-DP), a novel usage in the context of glucose prediction,
has the lowest. Despite having good RMSE values, we show that the models do not
necessarily exhibit a good clinical acceptability, measured by the CG-EGA. Only
the LSTM, SVR and GP-DP models have overall acceptable results, each of them
performing best in one of the glycemia regions
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