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Wenbin Shen

Publications and source records attributed to Wenbin Shen.

11 recordsLinked to original sources

Beyond the Last Layer: Global Inter-Layer Aggregation for AI-Generated Image Detection

The rapid development of generative models has made AI-generated images increasingly close to real images. It has also brought several challenges to detectors, including rapid generator updates, large changes in data distribution, and limited cross-dataset generalization. Many existing methods based on pretrained vision encoders primarily use the global representation from the last layer, potentially leaving useful information from intermediate layers underexplored. To address this issue, we propose Global Inter-Layer Aggregation (GILA). GILA extracts global representations from different depths of a frozen encoder, models interactions among layer representations through inter-layer self-attention, and adaptively aggregates the resulting contextualized representations. The method is not tied to a single pretraining objective and does not require fine-tuning the pretrained encoder. We evaluated GILA on three vision backbones with different pretraining objectives, ten seen generators, and three external datasets. The experimental results show that GILA makes better use of multi-layer information in pretrained encoders and improves detection performance and cross-dataset generalization.

cs.CV↗

Rethinking Multimodal Fake News Detection in the Generative AI Era

Generative content is increasingly entering the production and dissemination of news, transforming fake news from manually fabricated or simply manipulated material into complex forms in which native and generated content jointly participate. Existing multimodal fake news detection research primarily focuses on veracity assessment and rarely characterizes how generativity differences affect the reliability of evidence. In contrast, AIGC detection primarily determines whether content is generated or modified by generative models, but it does not by itself establish whether the underlying news event is true. To bridge the separation between these tasks in data and evaluation, we construct Weibo26, a multimodal fake news detection dataset for generative-content scenarios. On this basis, we propose the Generativity-Aware Hierarchical Reasoning (GAHR) framework, which combines global judgment with local correction so that generativity information participates in news-veracity reasoning. Experiments on multiple existing fake news detection benchmarks and Weibo26 show that GAHR achieves competitive veracity-detection performance while effectively identifying generative content.

cs.CL↗

RAEGNet: Relation-Aware Evidence Graph Network for Harm-Aware Multimodal Fake News Detection

Existing multimodal fake news detection methods often introduce external information to assist detection. However, most of them rely on entity-level retrieval and are therefore prone to introducing event-irrelevant noise. Meanwhile, existing methods mainly focus on improving overall performance and do not account for differences in the degree of harm posed by different instances of fake news. To address these limitations, we design an Event-Level Evidence Retrieval Framework (ELERF) and propose a Relation-Aware Evidence Graph Network (RAEGNet). ELERF retrieves external evidence based on the complete event semantics of a news item. RAEGNet constructs a directed graph that incorporates news-evidence stance relations and evidence-evidence interaction relations, and introduces a conditional-harm branch to jointly model authenticity and potential harm. Experimental results demonstrate that RAEGNet outperforms multiple baseline methods across all evaluated metrics on Weibo-21, Fakeddit, and our self-constructed SSS dataset.

cs.CL↗

Bare-Die Antiferromagnetic Computing

Semiconductor electronic devices are increasingly constrained by fundamental quantum tunneling effects and charge-based mechanisms, which severely limit further miniaturization, write-speed scaling, and environmental robustness of silicon-based technologies. These limitations are particularly prohibitive for deep-space exploration, where extreme temperatures, ultra-strong magnetic fields, and intense radiation rapidly incapacitate conventional electronics without massive shielding. Here, we present an intrinsically resilient, strain-mediated antiferromagnetic MnIr/PMN-PT edge processor that operates reliably as a bare die under temperatures up to 500 K, magnetic fields of 55 T, and radiation doses of 1.5 Mrad. By exploiting an input-modulated in situ self-refreshing encoding mechanism, the device performs nonlinear feature extraction and classification directly from raw analog signals, enabling an analog computing architecture that requires no time-frequency transformation. This architecture achieves 99.8% accuracy in speech recognition without digital preprocessing and 100% accuracy in astronaut visual object recognition. Furthermore, an all-hardware integrated drone vision system demonstrates real-time in situ command execution and autonomous navigation, delivering a terahertz-level response frequency and an ultra-low energy consumption of approximately 0.2 fJ per operation. This work expands the functional scope of antiferromagnetic devices beyond memory and logic, establishing them as a promising materials platform for energy-efficient physical computing and autonomous intelligence in extreme environments.

cond-mat.mes-hall↗

Satellite gravity constraints on inner core viscosity and LLVPs density anomalies

Constraining the physical properties of Earth's deep interior, particularly the viscosity of the solid inner core and the density structure of large low-velocity provinces (LLVPs), remains a major challenge in geophysics. Here we develop a unified dynamical framework that combines mantle-inner core gravitational coupling (MICG) with torsional oscillations in the fluid outer core and show that their interaction can produce a distinct and testable geodetic signature. Guided by this prediction, we analyze satellite gravity observations together with independent corrections for surface mass variability. We identify a robust approximately 6-year signal in the Stokes coefficient Delta S22, while no corresponding stationary signal is detected in Delta C22. A signal with the same periodicity is independently detected in length-of-day variations (Delta LOD), and the two signals exhibit a near anti-phase relationship. Interpreting this coupled signature within the proposed framework allows us to constrain the inner core viscosity to approximately 4.6 (+/- 1.8) x 10^16 Pa s and the equatorial relief of the inner core boundary to a semi-axis difference of about 200 +/- 70 m. The inversion further indicates mean density anomalies of +5.5 (+/- 0.6) per mil at the base of LLVPs. These results indicate that satellite gravimetry provides a direct observational window into deep-Earth dynamics and the physical properties of Earth's deep interior.

physics.geo-ph↗

Formulation of testing gravitational redshift based on Laser Time link between China Space Station and a ground station

This paper presents a high-precision gravitational redshift test using the China Space Station (CSS) Laser Time Transfer (CLT) system. We develop a comprehensive observation equation based on a c^{-3} order relativistic model for space-ground clock comparison. While the CSS optical clock system is currently in the orbital debugging phase, our simulation using actual CSS orbit data achieves a gravitational redshift verification precision of (1.8 \pm 47)*10^{-7} -- approximately one order of magnitude improvement over previous experiments. Our work represents the first application of laser-based time transfer for gravitational redshift verification at such precision, and the first use of the CSS CLT link for testing this fundamental aspect of General Relativity. Unlike microwave-based methods, our laser approach avoids ionospheric effects and first-order Doppler shifts. Residual analysis identifies tropospheric delay variations and atmospheric turbulence as the primary remaining uncertainty contributors. The achieved precision enables gravitational potential difference measurements with 0.1 m^2/s^2 precision -- offering new capabilities for both fundamental physics investigations and geodetic applications including intercontinental height transfer. This work establishes a new benchmark for high-precision tests of relativistic physics and demonstrates the transformative potential of space-based optical time transfer.

gr-qc↗

Satellite observations reveal shorter periodic inner core oscillation

Detecting the Earth's inner core motions relative to the mantle presents a considerable challenge due to their indirect accessibility. Seismological observations initially provided evidence for differential/super-rotation of the inner core, but recently demonstrated a possibly about 70-year periodic oscillation. The contrasting results underscore the ongoing enigma surrounding inner core motion, leaving debates unresolved, including the precise oscillate period. In parallel to seismic observations, satellite geodesy has accumulated decades of global high-precision records, providing a novel avenue to probe inner core motions. Here, we detect an about 6-year oscillation from the gravitational field degree-2 order-2 Stokes coefficients derived from satellite observations, and find it has a unique phase correlation with the about 6-year signal in the Earth's length-of-day variations. This correlation is attributed to an inner core oscillation which is controlled by the gravitational coupling between the inner core and lower mantle (mainly due to the density heterogeneity of the two large low-velocity provinces; LLVPs). That is, we independently corroborate the inner core periodic oscillation, albeit with a significantly shorter period than previously suggested. Our findings demonstrate the dense layer of the LLVPs (mean density anomalies of about +0.9 percent at the bottom), consistent with inversions from tidal tomography and Stoneley modes. Furthermore, our research reveals equatorial topographic undulations of about 187 m at the inner core boundary.

physics.geo-ph↗

Inner core static tilt inferred from intradecadal oscillation in the Earth's rotation

The geodynamic state of the inner core remains an enigma, encompassing the presence of a static tilt between the inner core and mantle. Following the experimental confirmation of an ~8.5yr signal in polar motion as the inner core wobble (ICW), a normal mode of the inner core, we report that the ~8.5yr oscillation contained in the length-of-day variations in the Earth's rotation has good phase consistency with it. Our analysis demonstrated a 0.17° static tilt of the inner core (more likely towards ~90°W) relative to the mantle, which is two orders of magnitude lower than the 10° assumed in certain geodynamic researches. This tilt is consistent with the assumption that the average density in the northwestern hemisphere of the inner core should be greater than that in the other regions. Besides, the observed ICW period (8.5yr) suggests a 0.52g/cm3 density jump at the inner core boundary.

physics.geo-ph↗

Testing gravitational redshift based on microwave frequency links onboard China Space Station

In 2022 China Space Station (CSS) will be equipped with atomic clocks and optical clocks with stabilities of $2 \times 10^{-16}$ and $8 \times 10^{-18}$, respectively, which provides an excellent opportunity to test gravitational redshift (GR) with higher accuracy than previous results. Based on high-precise frequency links between CSS and a ground station, we formulated a model and provided simulation experiments to test GR. Simulation results suggest that this method could test the GR at the accuracy level of $(0.27 \pm 2.15) \times10^{-7}$, more than two orders in magnitude higher than the result of the experiment of a hydrogen clock on board a flying rocket more than 40 years ago.

astro-ph.IM↗

New evidences for the fluctuation characteristic of intradecadal periodic signals in length-of-day variation

The intradecadal fluctuations in the length-of-day variation (dLOD) are considered likely to play an important role in core motions. Two intradecadal oscillations, with 5.9yr and 8.5yr periods (referred to as SYO and EYO, respectively), have been detected in previous studies. However, whether the SYO and the EYO have stable damping trends since 1962 and whether geomagnetic jerks are possible excitation sources for the SYO/EYO are still debated. In this study, based on different methods and dLOD records with different time span, we show robust evidences to prove that the SYO and the EYO have no stable damping trends since 1962, and we find that there is also a possible 7.6yr signal. To prove whether it is a periodic signal, we use the optimal sequence estimation method to stack 35 global geomagnetic records, the results also show an 7.6yr periodic signal which has an Y2,-2 spatial distribution, and it has a high degree of consistent synchronicity with the 7.6yr signal in dLOD. After confirming that the jerks have no special consistency with the peaks/valleys of the EYO/SYO, we confirm that the geomagnetic jerks seem to be related to sudden changes in the SYO/EYO time series and their excitation series; so we finally suggest that jerks are possible excitation sources of the SYO/EYO. Meanwhile, after using a deconvolution method, we estimate that the period P and quality factor Q of the SYO and the EYO are [P=5.85+/-0.06yr, Q larger than 180] and [P=8.455+/-0.17yr, Q larger than 350], respectively.

physics.geo-ph↗

Formulation of a Triaxial Three-Layered Earth Rotation: I. Theory and Rotational Normal Mode Solutions

In this study, we formulated a triaxial three-layered anelastic Earth rotation theory con-sidering various core mantle couplings, including the pressure and gravitational couplings acting on the inner core by the outer core and mantle, the viscoelectromagnetic couplings between the outer core and mantle, and between the outer and inner cores. With this formulation, we provided four numerical solutions for the rotational normal modes, including the Chandler Wobble (CW), Free Core Nutation (FCN), Free Inner Core Nutation (FICN), an the Inner Core Wobble (ICW). The triaxiality led to increased periods for the CW and ICW of about 0.01 and 0.35 mean solar days (d), respectively. The mantle anelasticity and ocean tide induced dissipations were mainly responsible for the CW, but contributed little to the FCN, while the viscoelectromagnetic coupling induced dissipations were mainly responsible for the FCN, FICN, and ICW. By investigating different types of couplings, we found that pressure coupling played the dominant role in prograde FICN, while viscoelectromagnetic or gravitational couplings either alone, or together gave rise to retrograde FICN. On the other hand, the ICW period varied extensively from 130 d to 21 yr under different core mantle coupling conditions.

physics.geo-ph↗