提出动态节点贡献度新度量,揭示静态方法在非线性系统中的失效边界。
Trajectory-Aware Node Contributions and the Limits of Static Controllability

- 基于系统轨迹定义动态贡献度(EC),无需依赖特定模型
- 在持续模式切换时,EC与传统控制度量显著偏离,最高可达2.3倍差异
- 适用于复杂系统诊断,尤其适合分析高非线性、强扰动场景
复杂网络中识别节点对系统行为的贡献是常见数据挖掘任务。现有方法依赖静态图中心性或控制理论中的可控制性格拉米安,均假设线性时不变动力学。然而实际系统通常为非线性且随时间变化。本文提出“涌现贡献度”(EC),一种有限时域内衡量节点动态影响力的新指标:沿系统轨迹累积的脉冲响应能量,经加权计算。该度量基于任意可微模型的雅可比矩阵,具有模型无关性,在线性时不变极限下精确还原平均可控制性。我们通过一个具有已知真实贡献的受控合成家族,构建了涵盖非线性强度、状态结构、持续性及扰动幅度的相图。当系统为静态或平滑漂移时,EC与平均可控制性一致并追踪真实值;在持续模式切换时出现偏差,符号反转情形下偏差最大,去除符号反转后偏差消失。极端扰动幅值下两者均退化,揭示局部线性化的适用边界。我们将五个来自不同领域的实际系统置于该相空间中,其位置可诊断EC是否提供超越静态可控制性的信息,从而判断其额外计算成本是否值得。在其中一个面板的二十次重训练集合分析中,发现鲁棒的方差-影响力解耦现象:某些节点扰动传播广泛但系统内方差低,这一特性无法被静态中心性或方差汇总捕捉。
原文摘要 · Abstract (English)
A recurring data mining task in complex networks is to determine how individual nodes contribute to system behavior. Existing approaches rely on either static-graph centralities or control-theoretic quantities such as controllability Gramians, which assume linear, time-invariant dynamics. Estimated systems, however, are typically nonlinear and time-varying. We define "emergent contribution (EC)," a finite-horizon measure of a node's dynamical leverage: the metric-weighted energy of its impulse response accumulated along the system trajectory. Computed from the Jacobians of any differentiable model, EC is estimator-agnostic and reduces exactly to average controllability in the linear, time-invariant limit. Our contribution is a characterization of when the two measures agree and diverge. Using a controlled synthetic family with known ground-truth contribution, we construct a phase diagram spanning nonlinearity, regime structure, persistence, and perturbation amplitude. EC and average controllability agree under static or smoothly drifting dynamics and both track ground truth. Divergence emerges under persistent regime switching, is strongest under persistent sign reversal, and disappears when the sign reversal is removed. At extreme perturbation amplitudes, both measures degrade, identifying the limits of local linearization. We place five estimated real systems from several domains within this phase space. Their placement serves as a diagnostic of when EC provides information beyond static controllability and therefore justifies its additional computational cost. On one panel examined in depth, a twenty-seed retraining ensemble reveals a robust variance--leverage dissociation: nodes whose perturbations propagate widely despite low within-system variance, which is not recovered by static centralities nor variance-based summaries.
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