45 research outputs found
Islanded Wind Energy Management System Based on Neural Networks
Wind power, as the main renewable energy source, is increasingly deployed and connected into electrical networks thanks to the development of wind energy conversion technologies. This dissertation is focusing on research related to wind power system include grid-connected/islanded wind power systems operation and control design, wind power quality, wind power prediction technologies, and its applications in microgrids. The doubly fed induction generator (DFIG) wind turbine is popular in the wind industry and thus has been researched in this Dissertation. In order to investigate reasons of harmonic generation in wind power systems, a DFIG wind turbine is modeled by using general vector representation of voltage, current and magnetic flux in the presence of harmonics. In this Dissertation, a method of short term wind power prediction for a wind power plant is developed by training neural networks in Matlab software based on historical data of wind speed and wind direction. The model proposed is shown to achieve a high accuracy with respect to the measured data. Based on the above research work, a microgrid with high wind energy penetration has been designed and simulated by using Matlab/Simulink. Besides wind energy, this microgrid system is operated with assistance of a diesel generator. A three-layer energy management system (EMS) is designed and applied in this microgrid system, which is to realize microgrid islanded operation under different wind conditions. Simulation results show that the EMS can ensure stable operation of the microgrid under varying wind speed situations
Topology Repairing of Disconnected Pulmonary Airways and Vessels: Baselines and a Dataset
Accurate segmentation of pulmonary airways and vessels is crucial for the
diagnosis and treatment of pulmonary diseases. However, current deep learning
approaches suffer from disconnectivity issues that hinder their clinical
usefulness. To address this challenge, we propose a post-processing approach
that leverages a data-driven method to repair the topology of disconnected
pulmonary tubular structures. Our approach formulates the problem as a keypoint
detection task, where a neural network is trained to predict keypoints that can
bridge disconnected components. We use a training data synthesis pipeline that
generates disconnected data from complete pulmonary structures. Moreover, the
new Pulmonary Tree Repairing (PTR) dataset is publicly available, which
comprises 800 complete 3D models of pulmonary airways, arteries, and veins, as
well as the synthetic disconnected data. Our code and data are available at
https://github.com/M3DV/pulmonary-tree-repairing.Comment: MICCAI 2023 Early Accepte
EmoTalk: Speech-Driven Emotional Disentanglement for 3D Face Animation
Speech-driven 3D face animation aims to generate realistic facial expressions
that match the speech content and emotion. However, existing methods often
neglect emotional facial expressions or fail to disentangle them from speech
content. To address this issue, this paper proposes an end-to-end neural
network to disentangle different emotions in speech so as to generate rich 3D
facial expressions. Specifically, we introduce the emotion disentangling
encoder (EDE) to disentangle the emotion and content in the speech by
cross-reconstructed speech signals with different emotion labels. Then an
emotion-guided feature fusion decoder is employed to generate a 3D talking face
with enhanced emotion. The decoder is driven by the disentangled identity,
emotional, and content embeddings so as to generate controllable personal and
emotional styles. Finally, considering the scarcity of the 3D emotional talking
face data, we resort to the supervision of facial blendshapes, which enables
the reconstruction of plausible 3D faces from 2D emotional data, and contribute
a large-scale 3D emotional talking face dataset (3D-ETF) to train the network.
Our experiments and user studies demonstrate that our approach outperforms
state-of-the-art methods and exhibits more diverse facial movements. We
recommend watching the supplementary video:
https://ziqiaopeng.github.io/emotalkComment: Accepted by ICCV 202
Spin Fluctuation Induced Linear Magnetoresistance in Ultrathin Superconducting FeSe Films
The discovery of high-temperature superconductivity in FeSe/STO has trigged
great research interest to reveal a range of exotic physical phenomena in this
novel material. Here we present a temperature dependent magnetotransport
measurement for ultrathin FeSe/STO films with different thickness and
protection layers. Remarkably, a surprising linear magnetoresistance (LMR) is
observed around the superconducting transition temperatures but absent
otherwise. The experimental LMR can be reproduced by magnetotransport
calculations based on a model of magnetic field dependent disorder induced by
spin fluctuation. Thus, the observed LMR in coexistence with superconductivity
provides the first magnetotransport signature for spin fluctuation around the
superconducting transition region in ultrathin FeSe/STO films
Interface induced Zeeman-protected superconductivity in ultrathin crystalline lead films
Two dimensional (2D) superconducting systems are of great importance to
exploring exotic quantum physics. Recent development of fabrication techniques
stimulates the studies of high quality single crystalline 2D superconductors,
where intrinsic properties give rise to unprecedented physical phenomena. Here
we report the observation of Zeeman-type spin-orbit interaction protected
superconductivity (Zeeman-protected superconductivity) in 4 monolayer (ML) to 6
ML crystalline Pb films grown on striped incommensurate (SIC) Pb layers on
Si(111) substrates by molecular beam epitaxy (MBE). Anomalous large in-plane
critical field far beyond the Pauli limit is detected, which can be attributed
to the Zeeman-protected superconductivity due to the in-plane inversion
symmetry breaking at the interface. Our work demonstrates that in
superconducting heterostructures the interface can induce Zeeman-type
spin-orbit interaction (SOI) and modulate the superconductivity
Quantum Griffiths singularity in three-dimensional superconductor to Anderson critical insulator transition
Disorder is ubiquitous in real materials and can have dramatic effects on
quantum phase transitions. Originating from the disorder enhanced quantum
fluctuation, quantum Griffiths singularity (QGS) has been revealed as a
universal phenomenon in quantum criticality of low-dimensional superconductors.
However, due to the weak fluctuation effect, QGS is very challenging to detect
experimentally in three-dimensional (3D) superconducting systems. Here we
report the discovery of QGS associated with the quantum phase transition from
3D superconductor to Anderson critical insulator in a spinel oxide MgTi2O4
(MTO). Under both perpendicular and parallel magnetic field, the dynamical
critical exponent diverges when approaching the quantum critical point,
demonstrating the existence of 3D QGS. Among 3D superconductors, MTO shows
relatively strong fluctuation effect featured as a wide superconducting
transition region. The enhanced fluctuation, which may arise from the mobility
edge of Anderson localization, finally leads to the occurrence of 3D quantum
phase transition and QGS. Our findings offer a new perspective to understand
quantum phase transitions in strongly disordered 3D systems