arXiv subjects

Xiaoxing Zhang

Publications and source records attributed to Xiaoxing Zhang.

4 recordsLinked to original sources

arXiv2026

EasyBCI Agent: Towards Universal Neural Data Preprocessing for Brain-Computer Interfaces

Brain-computer interfaces translate neural activity into device commands, yet their performance hinges on preprocessing that remains manual, expert-dependent and poorly reproducible. Large language model agents can automate scientific coding, but existing systems lack the modality coverage, raw-data isolation, experience accumulation and domain oversight that neural preprocessing requires. We introduce EasyBCI, a two-phase LLM agent that plans and executes preprocessing pipelines for six signal types. A Plan Agent profiles each recording into a text-only Data Fingerprint that never exposes raw data to the model and selects a literature-grounded operator sequence. An Execution Agent generates, runs and self-corrects code until quality criteria are met, while a quality-gated experience system retains validated strategies as reusable skills. A domain expert intervenes at two decision gates, retaining human judgement where undetected error can invalidate downstream analyses. Evaluation on EEG with a fixed linear classifier shows that all five EasyBCI backbones preserve more task-relevant separability than the manual pipeline. Under same-backbone comparison, EasyBCI outperforms general-purpose coding agents on both label schemes for four of five configurations. EasyBCI extends to five additional modalities spanning nearly three orders of magnitude in sampling rate, producing complete reproducible pipelines with recorded decision provenance. These results indicate that domain-specific orchestration can bring auditable preprocessing within reach of laboratories lacking dedicated expertise, illustrating design principles applicable to AI agents in other scientific domains.

q-bio.QM↗

arXiv2026

Semantic-Enhanced Time-Series Forecasting via Large Language Models

Time series forecasting plays a significant role in finance, energy, meteorology, and IoT applications. Recent studies have leveraged the generalization capabilities of large language models (LLMs) to adapt to time series forecasting, achieving promising performance. However, existing studies focus on token-level modal alignment, instead of bridging the intrinsic modality gap between linguistic knowledge structures and time series data patterns, greatly limiting the semantic representation. To address this issue, we propose a novel Semantic-Enhanced LLM (SE-LLM) that explores the inherent periodicity and anomalous characteristics of time series to embed into the semantic space to enhance the token embedding. This process enhances the interpretability of tokens for LLMs, thereby activating the potential of LLMs for temporal sequence analysis. Moreover, existing Transformer-based LLMs excel at capturing long-range dependencies but are weak at modeling short-term anomalies in time-series data. Hence, we propose a plugin module embedded within self-attention that models long-term and short-term dependencies to effectively adapt LLMs to time-series analysis. Our approach freezes the LLM and reduces the sequence dimensionality of tokens, greatly reducing computational consumption. Experiments demonstrate the superiority performance of our SE-LLM against the state-of-the-art (SOTA) methods.

cs.LG↗

arXiv2024

Mechanism of O$_2$ influence on the decomposition process of the eco-friendly gas insulating medium C$_4$F$_7$N/CO$_2$

The C$_4$F$_7$N/CO$_2$/O$_2$ gas mixture is the most promising eco-friendly gas insulation medium available. However, there are few studies on the mechanism of the influence of the buffer gas O2 ratio and its role in the decomposition characteristics of C4F7N/CO2. In this paper, based on the ReaxFF reaction molecular dynamics method and density functional theory, a simulation of the thermal decomposition process of the C$_4$F$_7$N/CO$_2$ mixture under different O2 ratios was carried out at temperatures in the range 2000-3000 K. A constructed model of the C4F7N/CO2/O2 mixture reaction system was used that included the possible reaction paths, product distribution characteristics and their generation rates. The calculation results show that the thermal decomposition of C$_4$F$_7$N/CO$_2$/O$_2$ mainly generates species such as CF$_3$, CF$_2$, CF, F, C$_2$F$_5$, C$_2$F$_4$, C$_2$F$_2$, C$_3$F$_7$, C$_2$F$_2$N, C$_3$F$_4$N, CFN, CN, CO, O, and C. Among them, the two particles CF$_2$ and CN are the most abundant. The first decomposition time of C$_4$F$_7$N is advanced by the addition of O$_2$, while the amount of C$_4$F$_7$N decomposed and the generation of major decomposed particles decreases. The addition of 0%-4% of O$_2$ decreases the reaction rate of the main decomposition reaction in the reaction system. Quantum chemical calculations show that the dissociation process occurring from the combination of C$_4$F$_7$N with O atom is more likely to occur compared to the direct dissociation process of C$_4$F$_7$N molecules. The conclusions of this study provide a theoretical basis for the optimization of the application ratio of C$_4$F$_7$N/CO$_2$/O$_2$ and the diagnosis of its equipment operation and maintenance.

physics.comp-ph↗

arXiv2018

Chiral Landau levels in Weyl semimetal NbAs with multiple topological carriers

Recently, Weyl semimetals have been experimentally discovered in both inversion-symmetry-breaking and time-reversal-symmetry-breaking crystals. The non-trivial topology in Weyl semimetals can manifest itself with exotic phenomena which have been extensively investigated by photoemission and transport measurements. Despite the numerous experimental efforts on Fermi arcs and chiral anomaly, the existence of unconventional zeroth Landau levels, as a unique hallmark of Weyl fermions which is highly related to chiral anomaly, remains elusive owing to the stringent experimental requirements. Here, we report the magneto-optical study of Landau quantization in Weyl semimetal NbAs. High magnetic fields drive the system towards the quantum limit which leads to the observation of zeroth chiral Landau levels in two inequivalent Weyl nodes. As compared to other Landau levels, the zeroth chiral Landau level exhibits a distinct linear dispersion in z momentum direction and allows the optical transitions without the limitation of zero z momentum or square root of magnetic field evolution. The magnetic field dependence of the zeroth Landau levels further verifies the predicted particle-hole asymmetry of the Weyl cones. Meanwhile, the optical transitions from the normal Landau levels exhibit the coexistence of multiple carriers including an unexpected massive Dirac fermion, pointing to a more complex topological nature in inversion-symmetry-breaking Weyl semimetals. Our results provide insights into the Landau quantization of Weyl fermions and demonstrate an effective tool for studying complex topological systems.

cond-mat.mes-hall↗