arXiv subjects

Xiangdong Li

Publications and source records attributed to Xiangdong Li.

At least 19 recordsLinked to original sources

arXiv2026

State-Anchored Complete-View Distillation for Robust Conversational Multimodal Emotion Recognition

Conversational multimodal emotion recognition (MER) requires reliable prediction when language, acoustic, or visual observations are missing or unreliable. Many missing-modality methods reconstruct absent inputs, yet such recovery can be non-unique in dialogue context, and nonverbal cues may conflict with the target utterance. To this end, we propose CoRe-KD (Complete-view Reference-guided Knowledge Distillation), a state-anchored, conflict-regularized complete-view distillation framework for robust conversational MER. A complete-view teacher provides structured references, including prediction-level references, fused states, and modality-specific states. Complete-view State Anchoring (CSA) aligns incomplete-view student predictions and states with these references, while Nonverbal Conflict Exposure (NCE) trains on target-preserving nonverbal conflict views to reduce donor-label bias. Experiments on IEMOCAP and MELD, with CMU-MOSEI as a supplementary utterance-level check, show consistent gains under fixed- and random-missing protocols. Comprehensive ablation studies and further analyses support the role of CSA and the complementary effect of NCE.

cs.MM↗

arXiv2026

SecGoal: A Benchmark for Extracting Formalizable Security Goals from Protocol Documents

Formal verification provides rigorous guarantees for cryptographic security, yet extracting formalizable security goals from natural-language protocol documents remains largely manual. We introduce SecGoal, a dedicated expert-annotated dataset and benchmark for extracting formalizable security goal statements from protocol documents, covering 15 widely deployed protocols, together with AIFG, a schema- and flow-conditioned framework for structured formal security property generation. Our evaluation shows that frontier and large LLMs achieve high property recall but low extraction precision because they often fail to distinguish formalizable security goals from non-goal protocol content. In contrast, SecGoal fine-tuning makes smaller open-source LLMs substantially more selective extractors of formalizable security goals. On the held-out test protocols, Gemma2-9B-FT improves extraction precision from 24.0\% to 66.6\% and reaches 97.6\% property recall, outperforming larger prompted LLMs and encoder baselines. In a controlled setting, AIFG shows that concise goal inputs can support high-recall structured property generation, while expert-vetted extracted inputs reveal over-generation as the main remaining bottleneck. Together, SecGoal and AIFG provide a dataset, benchmark, and framework for specification-grounded security goal extraction and property generation.

cs.CR↗

arXiv2026

Beyond Isolated Utterances: Cue-Guided Interaction for Context-Dependent Conversational Multimodal Understanding

Conversational multimodal understanding aims to infer the meaning or label of the current utterance from its preceding dialogue context together with textual, acoustic, and visual signals. Existing methods mainly strengthen contextual modeling through enhanced encoding, fusion, or propagation, but rarely abstract the context-utterance dependency into an explicit cue and incorporate it into later multimodal reasoning. To address this issue, we propose CUCI-Net for conversational multimodal understanding. CUCI-Net fully preserves the structural distinction between context and utterance during encoding, effectively abstracts their dependency into an interpretation cue by combining local modality evidence with global contextual evidence, and seamlessly integrates the resulting cue into the final multimodal interaction stage for context-conditioned prediction. Extensive experiments on mainstream benchmark datasets fully demonstrate the effectiveness of the proposed method.

cs.MM↗

arXiv2026

Euler-inspired Decoupling Neural Operator for Efficient Pansharpening

Pansharpening aims to synthesize high-resolution multispectral (HR-MS) images by fusing the spatial textures of panchromatic (PAN) images with the spectral information of low-resolution multispectral (LR-MS) images. While recent deep learning paradigms, especially diffusion-based operators, have pushed the performance boundaries, they often encounter spectral-spatial blurring and prohibitive computational costs due to their stochastic nature and iterative sampling. In this paper, we propose the Euler-inspired Decoupling Neural Operator (EDNO), a physics-inspired framework that redefines pansharpening as a continuous functional mapping in the frequency domain. Departing from conventional Cartesian feature processing, our EDNO leverages Euler's formula to transform features into a polar coordinate system, enabling a novel explicit-implicit interaction mechanism. Specifically, we develop the Euler Feature Interaction Layer (EFIL), which decouples the fusion task into two specialized modules: 1) Explicit Feature Interaction Module, utilizing a linear weighting scheme to simulate phase rotation for adaptive geometric alignment; and 2) Implicit Feature Interaction Module, employing a feed-forward network to model spectral distributions for superior color consistency. By operating in the frequency domain, EDNO inherently captures global receptive fields while maintaining discretization-invariance. Experimental results on the three datasets demonstrate that EDNO offers a superior efficiency-performance balance compared to heavyweight architectures.

cs.CV↗

arXiv2026

MAUGen: A Unified Diffusion Approach for Multi-Identity Facial Expression and AU Label Generation

The lack of large-scale, demographically diverse face images with precise Action Unit (AU) occurrence and intensity annotations has long been recognized as a fundamental bottleneck in developing generalizable AU recognition systems. In this paper, we propose MAUGen, a diffusion-based multi-modal framework that jointly generates a large collection of photorealistic facial expressions and anatomically consistent AU labels, including both occurrence and intensity, conditioned on a single descriptive text prompt. Our MAUGen involves two key modules: (1) a Multi-modal Representation Learning (MRL) module that captures the relationships among the paired textual description, facial identity, expression image, and AU activations within a unified latent space; and (2) a Diffusion-based Image label Generator (DIG) that decodes the joint representation into aligned facial image-label pairs across diverse identities. Under this framework, we introduce Multi-Identity Facial Action (MIFA), a large-scale multimodal synthetic dataset featuring comprehensive AU annotations and identity variations. Extensive experiments demonstrate that MAUGen outperforms existing methods in synthesizing photorealistic, demographically diverse facial images along with semantically aligned AU labels.

cs.CV↗

arXiv2025

Scientific Objectives of the Xue-shan-mu-chang 15-meter Submillimeter Telescope

Submillimeter astronomy is poised to revolutionize our understanding of the Universe by revealing cosmic phenomena hidden from optical and near-infrared observations, particularly those associated with interstellar dust, molecular gas, and star formation. The Xue-shan-mu-chang 15-meter submillimeter telescope (XSMT-15m), to be constructed at a premier high-altitude site (4813 m) in Qinghai, China, marks a major milestone for Chinese astronomy, establishing the China mainland's first independently developed, world-class submillimeter facility. Equipped with state-of-the-art instruments, XSMT-15m will address a diverse range of frontier scientific questions spanning extragalactic astronomy, Galactic structure, time-domain astrophysics, and astrochemistry. In synergy with current and forthcoming observatories, XSMT-15m will illuminate the formation and evolution of galaxies, unravel the physical and chemical processes shaping the interstellar medium, and explore transient phenomena in the submillimeter regime. These capabilities will advance our understanding across extragalactic astronomy, Galactic ecology, astrochemistry, and time-domain astrophysics, inaugurating a new era for submillimeter research in China and the northern hemisphere.

astro-ph.GA↗

arXiv2025

Dense Matter in Neutron Stars with eXTP

In this White Paper, we present the potential of the enhanced X-ray Timing and Polarimetry (eXTP) mission to constrain the equation of state of dense matter in neutron stars, exploring regimes not directly accessible to terrestrial experiments. By observing a diverse population of neutron stars - including isolated objects, X-ray bursters, and accreting systems - eXTP's unique combination of timing, spectroscopy, and polarimetry enables high-precision measurements of compactness, spin, surface temperature, polarimetric signals, and timing irregularity. These multifaceted observations, combined with advances in theoretical modeling, pave the way toward a comprehensive description of the properties and phases of dense matter from the crust to the core of neutron stars. Under development by an international Consortium led by the Institute of High Energy Physics of the Chinese Academy of Sciences, the eXTP mission is planned to be launched in early 2030.

astro-ph.HE↗

arXiv2025

The orbital period changes for novae

Cataclysmic variable (CVs) are close interacting binaries in which a white dwarf accretes materials from a low mass main sequence companion. CVs can experience nova eruptions due to low mass transfer rates. In the standard theory of CV evolution, the ejected materials during nova eruptions are assumed to leave the system in the form of fast, isotropic, optically thick winds, which predicts that novae only result in positive variation (expansion) of orbital period (i.e. positive $ΔP$). In addition, the angular momentum losses (magnetic braking and gravitational radiation) only predicts a steady long-term decay in the orbital period of CVs, i.e. $\dot P$ is negative. Interestingly, an observation lasting over 30 years reveals positive and negative values for both $ΔP$ and $\dot P$ in CVs, strongly conflicting with the standard evolutionary patterns. However, it cannot be excluded that these observations originate from short-term phenomena caused by nova eruptions because of a short timescale of observations. In this paper, we model the effect of instantaneous nova eruptions on the evolution of CVs, considering three mechanisms associated with mass loss in nova eruptions, including fast wind, Frank jet and binary-driven mass loss. By assuming that the observed $ΔP$ and $\dot P$ are dominated by short-term phenomena, our results show that the binary-driven mass loss can explain almost all of the observations of normal CVs. However, the Frank jet may be needed for some of long-period CVs with evolved companions.

astro-ph.SR↗

arXiv2025

Eclipsing millisecond pulsars with He star companions

Eclipsing millisecond pulsars (MSPs) are a type of pulsar binaries with close orbits ($\lesssim1.0\,$d). They are important objects for studying the accretion history of neutron stars (NSs), pulsar winds, and the origin of isolated MSPs, etc. Recently, a new eclipsing MSP, PSR J$1928+1815$, was discovered by the Five-hundred-meter Aperture Spherical radio Telescope. It is the first known pulsar with a He star companion, as suggested in Yang et al. The system features a short orbital period of $\sim0.15\,$d and a relatively massive companion $\gtrsim1.0\,M_\odot$. However, the origin of PSR J$1928+1815$ remains highly uncertain. In this paper, we investigated the formation of the new subclass of eclipsing MSPs containing (evolved) He star companions through NS + He star channel. We found that if a NS binary undergoes subsequent mass-transfer phases following Case BA or Case BB, it may appear as an eclipsing MSP during the detached phase. Additionally, we obtained the initial parameter space for producing eclipsing MSPs with He star companions. Using binary population synthesis approach, we estimated their birth rate to be $\sim2.1-4.7\times10^{-4}\rm\,yr^{-1}$, corresponding to a total number of $\sim55-150$ systems in the Galaxy. Moreover, we concluded that PSR J$1928+1815$ may originate from the evolution of an NS+He star system with an initial orbital period of $\sim0.1\,$d, which can undergo the Case BB mass transfer.

astro-ph.SR↗

arXiv2025

Super-bunching light with giant high-order correlations and extreme multi-photon events

Non-classical light sources emitting bundles of N-photons with strong correlation represent versatile resources of interdisciplinary importance with applications ranging from fundamental tests of quantum mechanics to quantum information processing. Yet, high-order correlations, gN(0),quantifying photon correlation, are still limited to hundreds. Here, we report the generation of a super-bunching light source in photonic crystal fiber with g2(0) reaching 5.86*104 and g5(0) up to 2.72*108, through measuring its photon number probability distributions. under giant g2(0) values, the super-bunching light source presents upturned-tail photon distributions and ubiquitous extreme multi-photon events, where 31 photons from a single light pulse at a mean of 1.99*10-4 photons per pulse have been determined. The probability of this extreme event has been enhanced by 10139 folds compared to a coherent laser with Poissonian distribution. By varying the power of the pumping laser, both photon number distributions and corresponding high-order correlations of this light source can be substantially tailored from Poissonian to super-bunching distributions. These phenomena are attributed to the synchronized nonlinear interactions in photonic crystal fibers pumping by bright squeezed light, and the theoretical simulations agree well with the experimental results. Our research showcases the ability to achieve non-classical light sources with giant high-order correlations and extreme multi-photon events, paving the way for high-order correlation imaging, extreme nonlinear optical effects, quantum information processing, and exploring light-matter interactions with multi-photon physics.

quant-ph↗

arXiv2025

On-demand manipulation of superbunching emission from colloidal quantum dots and its application in noise-resistance correlated biphoton imaging

Superbunching effect with second-order correlations larger than 2, $g^{(2)}(0)>2$, indicating the N-photon bundles emission and strong correlation among photons, has a broad range of fascinating applications in quantum illumination, communication, and computation. However, the on-demand manipulation of the superbunching effect in colloidal quantum dots (QDs) under pulsed excitation, which is beneficial to integrated photonics and lab-on-a-chip quantum devices, is still challenging. Here, we disclosed the evolution of $g^{(2)}(0)$ with the parameters of colloidal QDs by Mento Carlo simulations and performed second-order correlation measurements on CdSe/ZnS core/shell QDs under both continuous wave (CW) and pulsed lasers. The photon statistics of a single colloidal QD have been substantially tailored from sub-Poissonian distribution $g^{(2)}(0) <1$) to superbunching emission, with the maximum $g^{(2)}(0)$ reaching 69 and 20 under CW and pulsed excitation, respectively. We have achieved correlated biphoton imaging (CPI), employing the coincidence of the biexciton and bright exciton in one laser pulse, with the stray light and background noise up to 53 times stronger than PL emission of single colloidal QDs. By modulating the PL intensity, the Fourier-domain CPI with reasonably good contrast has been determined, with the stray light noise up to 107 times stronger than PL emission and 75600 times stronger than the counts of biphotons. Our noise-resistance CPI may enable laboratory-based quantum imaging to be applied to real-world applications with the highly desired suppression of strong background noise and stray light.

physics.optics↗

arXiv2025

Dwarf Galaxy Integral-field Survey (DGIS): survey overview and the result of global mass-metallicity relation

Low-mass galaxies are the building blocks of massive galaxies in the framework of hierarchical structure formation. To enable detailed studies of galactic ecosystems in dwarf galaxies by spatially resolving different galactic components, we have carried out the Dwarf Galaxy Integral-field Survey (DGIS). This survey aims to acquire observations with spatial resolutions as high as 10 to 100 pc while maintaining reasonably high signal-to-noise ratios with VLT/MUSE and ANU-2.3m/WiFeS. The whole sample will be composed of 65 dwarf galaxies with $M_{\rm \ast}$ $<$ 10$^{9}$ $\rm M_{\odot}$, selected from the Spitzer Local Volume Legacy Survey. The overall scientific goals include studying baryonic cycles in dwarf galaxies, searching for off-nuclear (intermediate)-massive black holes, and quantifying the inner density profiles of dark matter. In this work, we describe the sample selection, data reduction, and high-level data products. By integrating the spectra over the field of view for each galaxy, we obtained the integrated gas-phase metallicity and discussed its dependence on stellar mass and SFR. We find that the overall relation between metallicity and stellar mass of our DGIS nearly follows the extrapolation from the higher mass end. Its dispersion does not decrease by invoking the dependence on SFR.

astro-ph.GA↗

arXiv2024

Transformer-based toxin-protein interaction analysis prioritizes airborne particulate matter components with potential adverse health effects

Air pollution, particularly airborne particulate matter (PM), poses a significant threat to public health globally. It is crucial to comprehend the association between PM-associated toxic components and their cellular targets in humans to understand the mechanisms by which air pollution impacts health and to establish causal relationships between air pollution and public health consequences. Although many studies have explored the impact of PM on human health, the understanding of the association between toxins and the associated targets remain limited. Leveraging cutting-edge deep learning technologies, we developed tipFormer (toxin-protein interaction prediction based on transformer), a novel deep-learning tool for identifying toxic components capable of penetrating human cells and instigating pathogenic biological activities and signaling cascades. Experimental results show that tipFormer effectively captures interactions between proteins and toxic components. It incorporates dual pre-trained language models to encode protein sequences and chemicals. It employs a convolutional encoder to assimilate the sequential attributes of proteins and chemicals. It then introduces a learning module with a cross-attention mechanism to decode and elucidate the multifaceted interactions pivotal for the hotspots binding proteins and chemicals. Experimental results show that tipFormer effectively captures interactions between proteins and toxic components. This approach offers significant value to air quality and toxicology researchers by allowing high-throughput identification and prioritization of hazards. It supports more targeted laboratory studies and field measurements, ultimately enhancing our understanding of how air pollution impacts human health.

cs.LG↗

arXiv2024

A 44-minute periodic radio transient in a supernova remnant

Long-period radio transients (LPTs) are a newly discovered class of radio emitters with periods ranging from minutes to hours. The astrophysical nature remains undetermined, particularly of LPTs with no detectable companions. We report the first evidence for a plausible supernova remnant (SNR) association with an LPT (DART J1832-0911, 2656.23+-0.15 s period), which supports a neutron star origin of such objects. The dispersion measure of this LPT, SNR's CO emission and HI absorption, and low probability of chance of alignment with field pulsars are all consistent with such an association. The source displays either phase-locked circular or nearly 100\% linear polarization, indicating its strong and geometrically stable magnetic field. No detectable optical counterpart was found, even with a 10m-class telescope. The SNR association and the stable polarization suggest that DART J1832-0911 most likely originates from a young neutron star, whose spin could have been braked by supernova's fallback materials. This discovery provides critical insights into the nature of ultra-long period transients and their link to stellar remnants.

astro-ph.HE↗

arXiv2024

PGC 44685: A Dwarf Star-forming Lenticular Galaxy with Wolf-Rayet Population

Lenticular galaxies (S0s) are formed mainly from the gas stripping of spirals in the cluster. But how S0s form and evolve in the field is still untangled. Based on spatially resolved observations from the optical Hispanic Astronomical Center in Andalusia 3.5-m telescope with the PPAK Integral Field Spectroscopy instrument and NOrthern Extended Millimeter Array, we study a dwarf (M*<10^9 Msun) S0, PGC 44685, with triple star-forming regions in the central region, namely A, B, and C, respectively. In northwest region C, we clearly detect the spectral features of Wolf-Rayet (WR) stars and quantify the WR population by stacking spectra with high WR significance. Most of the molecular gas is concentrated in the region C(WR), and there is diffuse gas around regions A and B. The WR region possesses the strongest intensities of Ha, CO(1-0), and 3mm continuum, indicating its ongoing violent star formation (gas depletion timescale $\lesssim$25 Myr) with tentative hundreds (<500) km/s stellar winds accompanied by the WR phase. Most (~96%) of three star-forming regions show relatively low metallicity distributions, suggesting possible (minor) accretions of metal-poor gas that trigger the subsequent complex star formation in a field S0 galaxy. We speculate that PGC 44685 will become quiescent in less than 30 Myr if there is no new molecular gas to provide raw materials for star formation. The existence of this dwarf star-forming S0 presents an example of star formation in the low-mass/metallicity S0 galaxy.

astro-ph.GA↗

arXiv2024

On the magnetic braking law in black hole low-mass X-ray binaries

Magnetic braking (MB) plays an important role in the evolution of close low-mass X-ray binaries (LMXBs). It is also essential to the formation of ultracompact X-ray binaries (UCXBs). There have been lively investigations on the MB mechanism(s) in both single stars and close binaries including cataclysmic variables and neutron star (NS) LMXBs, but with diverse conclusions. In this paper we explore the effect of MB on the black hole (BH) LMXB evolution. We combine binary population synthesis with detailed binary evolution to obtain the expected properties of Galactic BH LMXB population. The simulated results are compared with the observational data including the BH mass, companion mass, companion temperature, orbital period, and mean accretion rate. Our results reveal that the MB laws with relatively low efficiency (i.e., RM12 and RVJ83) exhibit better agreement with observations, contrary to what was found for NS LMXBs. This raises the interesting question about whether MB really follows the same unified law in different types of binaries. We also predict that only a very small fraction ($\lesssim 2.5\%$) of BH LMXBs can evolve to be UCXBs. This explains why there is no BH UCXB discovered by far.

astro-ph.HE↗

arXiv2024

Detection of metal enrichment by SN 2011jm in NGC 4809

The cosmic metals are believed to originate from stellar and supernovae (SNe) nucleosynthesis, dispersed into the interstellar medium (ISM) through stellar winds and supernova explosions. In this paper, we present the clear evidence of metal enrichment by a type Ic SN 2011jm in the galaxy NGC 4809, utilizing high spatial resolution Integral Field Units (IFU) observations obtained from the Very Large Telescope (VLT)/Multi Unit Spectroscopic Explorer (MUSE). Despite SN 2011jm being surrounded by metal-deficient ISM ($\sim 0.25 \ Z_\odot$) at a scale about 100 pc, we clearly detect enriched oxygen abundance ($\sim 0.35 \ Z_\odot$) and a noteworthy nitrogen-to-oxygen ratio at the SN site. Remarkably, the metal pollution is confined to a smaller scale ( $\leq$ 13 pc). We posit that the enhanced ionized metal stems from stellar winds emitted by massive stars or previous SNe explosions. This observation may represent the first direct detection of chemical pollution by stellar feedback in star-forming galaxies beyond the Local Volume.

astro-ph.GA↗

arXiv2023

The He star donor channel towards the black widow PSR J1953+1844

Black widows (BWs) are a type of eclipsing millisecond pulsars (MSPs) with low companion masses ($\lesssim0.05\,\rm M_\odot$) and tight orbits ($<1\,$d). PSR J1953+1844 is a BW with the shortest orbital period ($\sim53$ minutes) ever discovered, which was recently detected by Five-hundred-meter Aperture Spherical radio Telescope. Its companion mass is $\sim0.01\,\rm M_\odot$ according to its mass function, indicating that the companion may be a hydrogen-deficient star. However, the origin of PSR J1953+1844 is highly unclear. In this paper, we explored the origin of PSR J1953+1844 through the neutron star+He star channel, in which the system can experience ultracompact X-ray binary phase. We found that the He star donor channel can reproduce the characteristics of PSR J1953+1844, indicating that this work provides an alternative formation channel for this source. Meanwhile, the minimum orbital period of BWs formed by this channel is $\sim28$ minutes, corresponding to the companion mass of $0.058\,\rm M_\odot$. In addition, we note that even though PSR J1953+1844 has a short orbital period, it cannot be detected by the gravitational wave (GW) observatories like Laser Interferometer Space Antenna, TaiJi and TianQin. However, we still expect that the BWs with extremely tight orbit produced by this channel are the potential sources of future space-based GW observatories. Moreover, our simulations show that PSR J1953+1844 may eventually evolve into an isolated MSP.

astro-ph.HE↗