Publications by Semin Kwak | EPFL Graph Search

A two-level resolution neural network with enhanced interpretability for freeway traffic forecasting

Nikolaos Geroliminis, Semin Kwak, Danya Li

© The Author(s) 2024.Deep learning models are widely used for traffic forecasting on freeways due to their ability to learn complex temporal and spatial relationships. In particular, graph neural networks, which integrate graph theory into deep learning, h ...

Nature Research2024

TwoResNet: Two-level resolution neural network for traffic forecasting on freeway networks

Nikolaos Geroliminis, Semin Kwak

Traffic forecasting problems of freeway networks are heavily tackled by deep learning methods because it requires learning highly complex correlations between variables both in time and space. Adopting a graph convolutional network (GCN) becomes a standard ...

IEEE2022

Multivariate time series forecasting for freeway networks

Semin Kwak

This dissertation introduces traffic forecasting methods for different network configurations and data availability. Chapter 2 focuses on single freeway cases. Although its topology is simple, the non-linearity of traffic features makes this prediction sti ...

EPFL2022

Travel Time Prediction for Congested Freeways With a Dynamic Linear Model

Nikolaos Geroliminis, Semin Kwak

Accurate prediction of travel time is an essential feature to support Intelligent Transportation Systems (ITS). The non-linearity of traffic states, however, makes this prediction a challenging task. Here we propose to use dynamic linear models (DLMs) to a ...

IEEE Institute of Electrical and Electronics Engineers2021

Traffic Signal Prediction on Transportation Networks Using Spatio-Temporal Correlations on Graphs

Pascal Frossard, Nikolaos Geroliminis, Semin Kwak

Multivariate time series forecasting poses challenges as the variables are intertwined in time and space, like in the case of traffic signals. Defining signals on graphs relaxes such complexities by representing the evolution of signals over a space using ...

2021

Improved neutron activation dosimetry for fusion

Olivier Sauter, Ambrogio Fasoli, Basil Duval, Stefano Coda, Jonathan Graves, Yves Martin, Duccio Testa, Patrick Blanchard, Alessandro Pau, Semin Kwak

Neutron activation technique has been widely used for the monitoring of neutron fluence at the Joint European Torus (JET) whereas it is foreseen to be employed at future fusion plants, such as ITER and DEMO. Neutron activation provides a robust tool for th ...

2019

Analysis of deposited layers with deuterium and impurity elements on samples from the divertor of JET with ITER-like wall

Olivier Sauter, Ambrogio Fasoli, Basil Duval, Stefano Coda, Yves Martin, Jonathan Graves, Duccio Testa, Cristian Sommariva, Patrick Blanchard, Bruno Emanuel Ferreira De Sousa Correia

Inconel-600 blocks and stainless steel covers for quartz microbalance crystals from remote corners in the JET-ILW divertor were studied with time-of-flight elastic recoil detection analysis and nuclear reaction analysis to obtain information about the area ...

2019

Tritium distributions on W-coated divertor tiles used in the third JET ITER-like wall campaign

Olivier Sauter, Ambrogio Fasoli, Basil Duval, Stefano Coda, Yves Martin, Jonathan Graves, Duccio Testa, Cristian Sommariva, Bruno Emanuel Ferreira De Sousa Correia, Patrick Blanchard

Tritium (T) distributions on tungsten (W)-coated plasma-facing tiles used in the third ITER-like wall campaign (2015-2016) of the Joint European Torus (JET) were examined by means of an imaging plate technique and beta-ray induced x-ray spectrometry, and t ...

Elsevier2019

Data-driven traffic and experienced travel time forecasting method for freeways with a localized linear regression model

Nikolaos Geroliminis, Semin Kwak

2019

Population modelling of the He II energy levels in tokamak plasmas: I. Collisional excitation model

Olivier Sauter, Ambrogio Fasoli, Basil Duval, Stefano Coda, Yves Martin, Jonathan Graves, Duccio Testa, Cristian Sommariva, Patrick Blanchard, Bruno Emanuel Ferreira De Sousa Correia

Helium is widely used as a fuel or minority gas in laboratory fusion experiments, and will be present as ash in DT thermonuclear plasmas. It is therefore essential to have a good understanding of its atomic physics. To this end He II population modelling h ...

IOP Publishing2019