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Hao Wen

Publications and source records attributed to Hao Wen.

72 records · Page 4Linked to original sources

AdaptiveNet: Post-deployment Neural Architecture Adaptation for Diverse Edge Environments

Deep learning models are increasingly deployed to edge devices for real-time applications. To ensure stable service quality across diverse edge environments, it is highly desirable to generate tailored model architectures for different conditions. However, conventional pre-deployment model generation approaches are not satisfactory due to the difficulty of handling the diversity of edge environments and the demand for edge information. In this paper, we propose to adapt the model architecture after deployment in the target environment, where the model quality can be precisely measured and private edge data can be retained. To achieve efficient and effective edge model generation, we introduce a pretraining-assisted on-cloud model elastification method and an edge-friendly on-device architecture search method. Model elastification generates a high-quality search space of model architectures with the guidance of a developer-specified oracle model. Each subnet in the space is a valid model with different environment affinity, and each device efficiently finds and maintains the most suitable subnet based on a series of edge-tailored optimizations. Extensive experiments on various edge devices demonstrate that our approach is able to achieve significantly better accuracy-latency tradeoffs (e.g. 46.74\% higher on average accuracy with a 60\% latency budget) than strong baselines with minimal overhead (13 GPU hours in the cloud and 2 minutes on the edge server).

cs.LG↗

Searching for Effective Neural Network Architectures for Heart Murmur Detection from Phonocardiogram

Aim: The George B. Moody PhysioNet Challenge 2022 raised problems of heart murmur detection and related abnormal cardiac function identification from phonocardiograms (PCGs). This work describes the novel approaches developed by our team, Revenger, to solve these problems. Methods: PCGs were resampled to 1000 Hz, then filtered with a Butterworth band-pass filter of order 3, cutoff frequencies 25 - 400 Hz, and z-score normalized. We used the multi-task learning (MTL) method via hard parameter sharing to train one neural network (NN) model for all the Challenge tasks. We performed neural architecture searching among a set of network backbones, including multi-branch convolutional neural networks (CNNs), SE-ResNets, TResNets, simplified wav2vec2, etc. Based on a stratified splitting of the subjects, 20% of the public data was left out as a validation set for model selection. The AdamW optimizer was adopted, along with the OneCycle scheduler, to optimize the model weights. Results: Our murmur detection classifier received a weighted accuracy score of 0.736 (ranked 14th out of 40 teams) and a Challenge cost score of 12944 (ranked 19th out of 39 teams) on the hidden validation set. Conclusion: We provided a practical solution to the problems of detecting heart murmurs and providing clinical diagnosis suggestions from PCGs.

cs.LG↗

Point Primitive Transformer for Long-Term 4D Point Cloud Video Understanding

This paper proposes a 4D backbone for long-term point cloud video understanding. A typical way to capture spatial-temporal context is using 4Dconv or transformer without hierarchy. However, those methods are neither effective nor efficient enough due to camera motion, scene changes, sampling patterns, and the complexity of 4D data. To address those issues, we leverage the primitive plane as a mid-level representation to capture the long-term spatial-temporal context in 4D point cloud videos and propose a novel hierarchical backbone named Point Primitive Transformer(PPTr), which is mainly composed of intra-primitive point transformers and primitive transformers. Extensive experiments show that PPTr outperforms the previous state of the arts on different tasks.

cs.CV↗

Electromagnetic counterparts of high-frequency gravitational waves having additional polarization states: distinguishing and probing tensor-mode, vector-mode and scalar-mode gravitons

GWs from extra dimensions, very early universe, and some high-energy astrophysical process, might have at most six polarizations: plus- and cross-type (tensor-mode gravitons), x-, y-type (vector-mode), and b-, l-type (scalar-mode). Peak or partial peak regions of some of such GWs are just distributed in GHz or higher frequency band, which would be optimal band for electromagnetic(EM) response. In this paper we investigate EM response to such high-frequency GWs(HFGWs) having additional polarizations. For the first time we address:(1)concrete forms of analytic solutions for perturbed EM fields caused by HFGWs having all six possible polarizations in background stable EM fields; (2)perturbed EM signals of HFGWs with additional polarizations in three-dimensional-synchro-resonance-system(3DSR system) and in galactic-extragalactic background EM fields. These perturbative EM fields are actually EM counterparts of HFGWs, and such results provide a novel way to simultaneously distinguish and display all possible six polarizations. It is also shown: (i)In EM response, pure cross-, x-type and pure y-type polarizations can independently generate perturbative photon fluxes(PPFs, signals), while plus-, b- and l-type polarizations produce PPFs in different combination states. (ii) All such six polarizations have separability and detectability. (iii)In EM response to HFGWs from extra-dimensions, distinguishing and displaying different polarizations would be quite possible due to their very high frequencies, large energy densities and special properties of spectrum. (iv)Detection band(10^8 to 10^12 Hz or higher) of PPFs by 3DSR and observation range(7*10^7 to 3*10^9 Hz) of PPFs by FAST (Five-hundred-meter-Aperture-Spherical Telescope, China), have a certain overlapping property, so their coincidence experiments will have high complementarity.

gr-qc↗

Differentiable Particle Filters through Conditional Normalizing Flow

Differentiable particle filters provide a flexible mechanism to adaptively train dynamic and measurement models by learning from observed data. However, most existing differentiable particle filters are within the bootstrap particle filtering framework and fail to incorporate the information from latest observations to construct better proposals. In this paper, we utilize conditional normalizing flows to construct proposal distributions for differentiable particle filters, enriching the distribution families that the proposal distributions can represent. In addition, normalizing flows are incorporated in the construction of the dynamic model, resulting in a more expressive dynamic model. We demonstrate the performance of the proposed conditional normalizing flow-based differentiable particle filters in a visual tracking task.

cs.AI↗

End-To-End Semi-supervised Learning for Differentiable Particle Filters

Recent advances in incorporating neural networks into particle filters provide the desired flexibility to apply particle filters in large-scale real-world applications. The dynamic and measurement models in this framework are learnable through the differentiable implementation of particle filters. Past efforts in optimising such models often require the knowledge of true states which can be expensive to obtain or even unavailable in practice. In this paper, in order to reduce the demand for annotated data, we present an end-to-end learning objective based upon the maximisation of a pseudo-likelihood function which can improve the estimation of states when large portion of true states are unknown. We assess performance of the proposed method in state estimation tasks in robotics with simulated and real-world datasets.

cs.LG↗

Ultra-low-frequency electromagnetic waves as signals and special counterparts of gravitational waves (from binary mergers) having tensorial and possible nontensorial polarizations

Gravitational waves (GWs, from binary merger) interacting with super-strong magnetic fields of the neutron star (in the same binary system), would lead to perturbed electromagnetic waves [EMWs, in the same frequencies of these GWs, partially in the ultra-low-frequency (ULF) band for the EMWs]. Such perturbed ULF-EMWs are not only the signals, but also a new type of special EM counterparts of the GWs. Here, generation of the perturbed ULF-EMWs is investigated for the first time, and the strengths of their magnetic components are estimated to be around 10^{-12}Tesla to 10^{-17}Tesla (in fISCO) at the Earth for various cases [not including the influence of interstellar medium (ISM)].The components with higher frequencies of the ULF-EMWs (e.g., especially produced by the GWs of the post-merger stage) above 1.8kHz (typical plasma frequency around solar system in the Milky way), could propagate through the ISM from the source until the Earth, and the perturbed ULF-EMWs will be reprocessed before they arrived at the Earth due to the ISM. Also, the waveforms of the perturbed ULF-EMWs will be modified into shapes different but related to the waveforms of the GWs, by the amplification process during the binary mergers which could amplify the magnetic fields into 10^{12}Tesla or even higher. Specific connection relationships between the polarizations of the perturbed ULF-EMWs and the polarizations (tensorial and possible nontensorial) of the GWs of binary mergers, are also addressed here. Characteristic properties of the perturbed ULF-EMWs (which would bring us some different new information of fundamental properties of the gravity and Universe) will be very helpful for extracting the signals from background noise for possible observations in the future.

physics.gen-ph↗

Distinctive electromagnetic signals caused by gravitational waves (of sub-solar mass primordial black hole binary mergers) interacting with galactic magnetic fields

As a candidate of dark matter, and related to many fundamental physics issues, the primordial black hole (PBH) is a crucial topic. However, so far the existence of PBHs is still not confirmed, and currently running GW detectors are still not able to distinguish them from the normal astrophysical BHs. In this article, we propose that the GWs (of PBH binary mergers) could interact with the very widespread background galactic magnetic fields in the Milky way, to produce the perturbed electromagnetic waves (EMWs) with unique characteristics of frequencies, waveforms, spectra and polarizations. In order to be distinguished from astrophysical black holes, only the PBHs with masses less than the solarmass are considered here, and their binary mergers will radiate GWs in frequencies much higher above the plasma frequency of interstellar medium (ISM), so corresponding perturbed EMWs (in the same frequencies to such GWs) can propagate through the ISM until the Earth. Our estimations show that, for the sub-solar mass PBH binary mergers within the Milky way (disk or halo), the strengths of the perturbed EMWs turn into constant levels around 10^{-12} Tesla (for magnetic components) and around 10^{-10}Watt m^{-2} (for energy flux densities) at the Earth, generally for all cases of different PBH masses (and not dependent on the distance of sources), and the same mass ratio of the PBH binary gives the same strength (at the Earth) of perturbed EMWs despite different PBH masses (GW frequencies) or binary distances. Differently, for the PBH binary mergers outside the Milky way, the perturbed EMWs at Earth have lower strengths (and depend on the distance of sources), but for some part of distance range, they would also be detectable. If such EM signals and special EM counterpart of GWs from PBHs could be detected by space- or land-based EMWs detectors, it may provide direct evidence of the PBHs.

physics.gen-ph↗

The structural and electronic properties of Stone-Wales defective zigzag/armchair antimonene nanotubes: First-principles calculations

Geometric optimization and electronic properties of Stone-Wales defective antimonene nanotubes are calculated by the method of first -principle calculations based on density functional theory. Various nanotubes are investigated according to the possible orientations of zigzag/armchair nanostructures when Stone-Wales defects are formed. The band structures, partial density of states and atomic orbitals are calculated to reveal the mechanism of influence of Stone-Wales defects on antimonene nanotubes. When the structure of antimonene changes from monolayer to tube, the indirect gap semiconductor antimonene transforms to a direct gap one. Moreover, the character of direct band gap for the antimonene nanotube is preserved with the Stone-Wales defect forming, while the energy of conduction band bottoms change due to the intervene of the defect energy level in the band gaps. These results may provide valuable references to the development and design of novel nanotubes based on antimonene nanotubes.

cond-mat.mtrl-sci↗

On the L2-Hodge theory of Landau-Ginzburg models

Let X be a non-compact Calabi-Yau manifold and f be a holomorphic function on X with compact critical locus. We introduce the notion of f-twisted Sobolev spaces for the pair (X,f) and prove the corresponding Hodge-to-de Rham degeneration property via L2-Hodge theoretical methods when f satisfies an asymptotic condition of strongly ellipticity. This leads to a Frobenius manifold via the Barannikov-Kontsevich construction, unifying the Landau-Ginzburg and Calabi-Yau geometry. Our construction can be viewed as a generalization of K.Saito's higher residue and primitive form theory for isolated singularities. As an application, we construct Frobenius manifolds for orbifold Landau-Ginzburg B-models which admit crepant resolutions.

math-ph↗

Counting Multiplicities in a Hypersurface over a Number Field

We fix a counting function of multiplicities of algebraic points in a projective hypersurface over a number field, and take the sum over all algebraic points of bounded height and fixed degree. An upper bound for the sum with respect to this counting function will be given in terms of the degree of the hypersurface, the dimension of the singular locus, the upper bounds of height, and the degree of the field of definition.

math.AG↗

Very high frequency gravitational waves from magnetars and gamma-ray burst

Extremely powerful astrophysical electromagnetic (EM) system could be possible source of high-frequency gravitational waves (HFGWs). Here based on properties of magnetars and gamma-ray bursts (GRBs), we address "Gamma-HFGWs" (with very high-frequency around 10^{20}Hz) caused by ultra-strong EM radiations (in the radiation-dominated phase of GRBs fireball) interacting with super-high magnetar surface magnetic fields (around 10^{11}Tesla). By certain parameters of distance and power, the Gamma-HFGWs would have far field energy density around 10^{-6}, and they would cause perturbed signal EM waves of around 10^{-20}Watt/m^2 in planned HFGW detection system based on EM response to GWs. Specially, Gamma-HFGWs would possess distinctive envelopes with characteristic shapes depending on the particular structures of surface magnetic fields of magnetars, which could be exclusive features helpful to distinguish them from background noise. Results obtained suggest that magnetars could involve in possible astrophysical EM sources of GWs in very high-frequency band, and Gamma-HFGWs would be potential targets for observations in the future.

gr-qc↗

Quasi-B-mode generated by high-frequency gravitational waves and corresponding perturbative photon fluxes

Interaction of very low-frequency primordial(relic) gravitational waves(GWs) to cosmic microwave background(CMB) can generate B-mode polarization. Here, for the first time we point out that the electromagnetic(EM) response to high-frequency GWs(HFGWs) would produce quasi-B-mode distribution of the perturbative photon fluxes, and study the duality and high complementarity between such two B-modes. Based on this quasi-B-mode in HFGWs, it is shown that the distinguishing and observing of HFGWs from the braneworld would be quite possible due to their large amplitude, higher frequency and very different physical behaviors between the perturbative photon fluxes and background photons, and the measurement of relic HFGWs may also be possible though face to enormous challenge.

gr-qc↗

Gravitational Quasinormal Modes of Regular Phantom Black Hole

We investigate the gravitational quasi-normal modes (QNMs) for a type of regular black hole (BH) known as phantom BH, which is a static self-gravitating solution of a minimally coupled phantom scalar field with a potential. The studies are carried out for three different spacetimes: asymptotically flat, de Sitter (dS), and anti de Sitter (AdS). In order to consider the standard odd parity and even parity of gravitational perturbations, the corresponding master equations are derived. The QNMs are discussed by evaluating the temporal evolution of the perturbation field which, in turn, provides direct information on the stability of BH spacetime. It is found that in asymptotically flat, dS and AdS spacetimes, the gravitational perturbations have similar characteristics for both odd and even parities. The decay rate of perturbation is strongly dependent on the scale parameter $b$, which measures the coupling strength between phantom scalar field and the gravity. Furthermore, through the analysis of Hawking radiation, it is shown that the thermodynamics of such regular phantom BH is also influenced by $b$. The obtained results might shed some light on the quantum interpretation of QNM perturbation.

gr-qc↗

Resonance of Gaussian electromagnetic field to the high frequency gravitational waves

We consider a Gaussian Beam (GB) resonant system for high frequency gravitational waves (HFGWs) detection. At present, we find the optimal signal strength in theory through setting the magnetic component of GB in a standard gaussian form. Under the synchro-resonance condition, we study the signal strength (i.e., transverse perturbative photon fluxes) from the relic HFGWs (predicted by ordinary inflationary model) and the braneworld HFGWs (from braneworld scenarios). Both of them would generate potentially detectable transverse perturbative photon fluxes (PPFs). Furthermore we find optimal system parameters and the relationship between frequency and effective width of energy fluxes accumulation.

gr-qc↗

Signal photon flux generated by high-frequency relic gravitational waves

The power spectrum of primordial tensor perturbations $\mathcal{P}_t$ increases rapidly in high frequency region if the spectral index $n_t>0$. It is shown that the amplitude of relic gravitational wave $h_t$($5\times10^9$Hz) varies from $10^{-36}$ to $10^{-25}$ while $n_t$ varies from $-6.25\times 10^{-3}$ to $0.87$. High frequency gravitational waves detector that is proposed by F.-Y. Li detects gravitational waves through observing the perturbed photon flux that is generated by interaction between the relic gravitational waves and electromagnetic system. It is shown that the perturbative photon flux $N_x^1$($5\times10^9$Hz) varies from $1.40\times10^{-4}\rm s^{-1}$ to $2.85\times10^{7}\rm s^{-1}$ while $n_t$ varies from $-6.25\times 10^{-3}$ to $0.87$. Correspondingly, the ratio of the transverse perturbative photon flux $N_x^1$ to the background photon flux varies from $10^{-28}$ to $10^{-16}$.

physics.gen-ph↗

A twisted $\bar{\partial}_f$-Neumann problem and Toeplitz $n$-tuples from singularity theory

A twisted $\bar{\partial}_f$-Neumann problem associated to a singularity $(\mathscr{O}_n,f)$ is established. By constructing the connection to the Koszul complex for toeplitz $n$-tuples $(f_1,\cdots,f_n)$ on Bergman spaces $B^0(D)$, we can solve this $\bar{\partial}_f$-Neumann problem. Moreover, we can compute the cohomology of the $L^2$ holomorphic Koszul complex $(B^*(D),\partial f\wedge)$ explicitly

math.CV↗

Field Experimental "Star Type" Metropolitan Quantum Key Distribution Network

Quantum key distribution (QKD) network has recently attracted growing attentions. Due to the special characteristics of quantum information, to build a full-connectivity QKD network without trusted relays is a stimulating challenge. In this letter, we report on the first realization of QKD network without trusted relays which covers metropolis in the commercial backbone optical fiber networks. The star topology four-user QKD network automatically addresses the quantum signal with a quantum router (QR) and every user in the network can receive and distribute quantum keys to any others simultaneously. The longest and the shortest length of fibers between two geographically separated nodes are 42.6km and 32km respectively, and the maximum average quantum bit error rate (QBER) is below 8%. This result opens a new possibility for the use of QKD into existing network.

quant-ph↗