185 research outputs found
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Steady-state analysis techniques for coupled device and circuit simulation
The focus of this work is on the steady-state analysis of RE circuits using a coupled device and circuit simulator. Efficient coupling algorithms for both the time-domain shooting method and the frequency-domain harmonic balance method have been developed. A modified Newton shooting method considerably improves the efficiency and reliability of the time-domain analysis. Three different implementation approaches of the harmonic balance method for coupled device and circuit simulation are investigated and implemented. These include the quasi-static, non-quasi-static, and modified-Volterra-series approaches. Comparisons of simulation and performance results identify the strengths and weakness of these approaches in terms of accuracy and efficiency
Phase transitions and topological properties of the 5/2 quantum Hall states with strong Landau-level mixing
We numerically study a 5/2 fractional quantum Hall system with even number of
electrons using the exact diagonalization where both the strong Landau level
(LL) mixing and a finite width of the quantum well have been considered and
adapted into a screened Coulomb interaction. With the principal component
analysis, we are able to recognize a compressible-incompressible phase
transition in the parameter space made of the magnetic field and the quantum
well width by the competition between the first two leading components of the
ground states wave functions, which is consistent with the low-lying spectral
feature and previous works in the odd-electron system. In addition, the
presence of the subdominant third component suggests an incompressible
transition occurring as the LL-mixing strength grows into a certain parameter
region associated with the ZnO experiments. We further investigate the strongly
LL-mixed phase in this emerging region with the Hall viscosity, wave function
overlaps, and the entanglement spectra. Results show it can be well described
as a particle-hole symmetrized Pfaffian state with the dual topological
properties of the Pfaffian and the anti-Pfaffian states
Quantum Multicritical Behavior for Coupled Optical Cavities with Driven Laser Fields
Quantum phase transitions with multicritical points are fascinating phenomena
occurring in interacting quantum many-body systems. However, multicritical
points predicted by theory have been rarely verified experimentally; finding
multicritical points with specific behaviors and realizing their control
remains a challenging topic. Here, we propose a system that a quantized light
field interacts with a two-level atomic ensemble coupled by microwave fields in
optical cavities, which is described by a generalized Dicke model.
Multicritical points for the superradiant quantum phase transition are shown to
occur. We determine the number and position of these critical points and
demonstrate that they can be effectively manipulated through the tuning of
system parameters. Particularly, we find that the quantum critical points can
evolve into a Lifshitz point if the Rabi frequency of the light field is
modulated periodically in time. Remarkably, the texture of atomic pseudo-spins
can be used to characterize the quantum critical behaviors of the system. The
magnetic orders of the three phases around the Lifshitz point, represented by
the atomic pseudo-spins, are similar to those of an axial
next-nearest-neighboring Ising model. The results reported here are beneficial
for unveiling intriguing physics of quantum phase transitions and pave the way
towards to find novel quantum multicritical phenomena based on the generalized
Dicke model
Double Graphs Regularized Multi-view Subspace Clustering
Recent years have witnessed a growing academic interest in multi-view
subspace clustering. In this paper, we propose a novel Double Graphs
Regularized Multi-view Subspace Clustering (DGRMSC) method, which aims to
harness both global and local structural information of multi-view data in a
unified framework. Specifically, DGRMSC firstly learns a latent representation
to exploit the global complementary information of multiple views. Based on the
learned latent representation, we learn a self-representation to explore its
global cluster structure. Further, Double Graphs Regularization (DGR) is
performed on both latent representation and self-representation to take
advantage of their local manifold structures simultaneously. Then, we design an
iterative algorithm to solve the optimization problem effectively. Extensive
experimental results on real-world datasets demonstrate the effectiveness of
the proposed method
A rule based fuzzy synthetic evaluation method for risk assessment in pipeline transport
Integrity Management Program (IMP) for oil and gas pipeline system demands a robust risk assessment method, which needs fully utilize the expert knowledge on the empirical data and the ambiguous cause(s) – effect(s) failure mechanism and then keep a good balance between precision and practicality. A new method, Rule Based Fuzzy Synthetic Evaluation (RB-FSE) which combines Fuzzy Synthetic Evaluation (FSE) with Fuzzy Logic (FLo) is proposed in this paper. It is applied to the pipeline risk assessment for Third-Party Damage (TPD). The proposed method is compared with scoring-type method in a case study. Results indicate that the relative assessment values from RB-FSE model could better support risk-ranking and decision-making in the IMP
Data-Efficient Image Quality Assessment with Attention-Panel Decoder
Blind Image Quality Assessment (BIQA) is a fundamental task in computer
vision, which however remains unresolved due to the complex distortion
conditions and diversified image contents. To confront this challenge, we in
this paper propose a novel BIQA pipeline based on the Transformer architecture,
which achieves an efficient quality-aware feature representation with much
fewer data. More specifically, we consider the traditional fine-tuning in BIQA
as an interpretation of the pre-trained model. In this way, we further
introduce a Transformer decoder to refine the perceptual information of the CLS
token from different perspectives. This enables our model to establish the
quality-aware feature manifold efficiently while attaining a strong
generalization capability. Meanwhile, inspired by the subjective evaluation
behaviors of human, we introduce a novel attention panel mechanism, which
improves the model performance and reduces the prediction uncertainty
simultaneously. The proposed BIQA method maintains a lightweight design with
only one layer of the decoder, yet extensive experiments on eight standard BIQA
datasets (both synthetic and authentic) demonstrate its superior performance to
the state-of-the-art BIQA methods, i.e., achieving the SRCC values of 0.875
(vs. 0.859 in LIVEC) and 0.980 (vs. 0.969 in LIVE).Comment: Accepted by AAAI 202
FindVehicle and VehicleFinder: A NER dataset for natural language-based vehicle retrieval and a keyword-based cross-modal vehicle retrieval system
Natural language (NL) based vehicle retrieval is a task aiming to retrieve a
vehicle that is most consistent with a given NL query from among all candidate
vehicles. Because NL query can be easily obtained, such a task has a promising
prospect in building an interactive intelligent traffic system (ITS). Current
solutions mainly focus on extracting both text and image features and mapping
them to the same latent space to compare the similarity. However, existing
methods usually use dependency analysis or semantic role-labelling techniques
to find keywords related to vehicle attributes. These techniques may require a
lot of pre-processing and post-processing work, and also suffer from extracting
the wrong keyword when the NL query is complex. To tackle these problems and
simplify, we borrow the idea from named entity recognition (NER) and construct
FindVehicle, a NER dataset in the traffic domain. It has 42.3k labelled NL
descriptions of vehicle tracks, containing information such as the location,
orientation, type and colour of the vehicle. FindVehicle also adopts both
overlapping entities and fine-grained entities to meet further requirements. To
verify its effectiveness, we propose a baseline NL-based vehicle retrieval
model called VehicleFinder. Our experiment shows that by using text encoders
pre-trained by FindVehicle, VehicleFinder achieves 87.7\% precision and 89.4\%
recall when retrieving a target vehicle by text command on our homemade dataset
based on UA-DETRAC. The time cost of VehicleFinder is 279.35 ms on one ARM v8.2
CPU and 93.72 ms on one RTX A4000 GPU, which is much faster than the
Transformer-based system. The dataset is open-source via the link
https://github.com/GuanRunwei/FindVehicle, and the implementation can be found
via the link https://github.com/GuanRunwei/VehicleFinder-CTIM
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