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| """ NTSM: Neurophysiology-Guided Tri-Stream Selective State Space Model
论文: IEEE J-BHI 2026, doi:10.1109/JBHI.2026.3727477
核心方法: 基于Mamba的选择性状态空间模型 三流分别处理不同EEG频段和EOG特征 """
import torch import torch.nn as nn import torch.nn.functional as F import math
class SelectiveSSM(nn.Module): """ 选择性状态空间模型 (基于Mamba架构) 与传统Transformer不同, SSM的推理复杂度为O(N)而非O(N²) 选择性机制允许模型根据输入内容动态调整参数 """ def __init__(self, d_model: int, d_state: int = 16, d_conv: int = 4): super().__init__() self.d_model = d_model self.d_state = d_state self.in_proj = nn.Linear(d_model, d_model * 2) self.conv1d = nn.Conv1d( d_model, d_model, kernel_size=d_conv, padding=d_conv - 1 ) self.x_proj = nn.Linear(d_model, d_state * 2 + 2 * d_model) A = torch.randn(d_model, d_state) * 0.01 self.A_log = nn.Parameter(torch.log(torch.abs(A) + 1e-6)) self.D = nn.Parameter(torch.ones(d_model)) self.out_proj = nn.Linear(d_model, d_model) def forward(self, x): """ Args: x: (B, L, D) 输入序列 Returns: y: (B, L, D) 输出序列 """ B, L, D = x.shape xz = self.in_proj(x) x_in, z = xz.chunk(2, dim=-1) x_in = self.conv1d(x_in.transpose(1, 2)).transpose(1, 2) x_in = F.silu(x_in) ssm_params = self.x_proj(x_in) dA, dB, C, gate = torch.split( ssm_params, [self.d_model, self.d_state, self.d_model, self.d_state], dim=-1 ) A = -torch.exp(self.A_log) dt = F.softplus(dA) y = torch.zeros_like(x_in) h = torch.zeros(B, D, self.d_state, device=x.device) for t in range(L): dt_t = dt[:, t, :] A_discrete = torch.exp(A.unsqueeze(0) * dt_t.unsqueeze(-1)) B_discrete = dB[:, t, :].unsqueeze(1) * dt_t.unsqueeze(-1) h = A_discrete * h + B_discrete * x_in[:, t, :].unsqueeze(-1) y[:, t, :] = (h * C[:, t, :].unsqueeze(1)).sum(-1) + self.D * x_in[:, t, :] y = y * F.silu(z) y = self.out_proj(y) return y
class TriStreamNTSM(nn.Module): """ NTSM: 三流选择性状态空间模型 流1: EEG慢波 (δ+θ) — 与疲劳正相关 流2: EEG快波 (α+β) — 与警觉正相关 流3: EOG特征 — 眨眼/眼动模式 神经生理学依据: - δ(0.5-4Hz): 深睡眠, 高δ→深度困倦 - θ(4-8Hz): 浅睡眠, 高θ→疲劳初期 - α(8-13Hz): 放松清醒, 低α→警觉下降 - β(13-30Hz): 活跃思考, 高β→高度警觉 - EOG: PERCLOS, 眨眼频率下降→疲劳 """ def __init__(self, eeg_channels: int = 32, eog_channels: int = 4, seq_length: int = 1000, sampling_rate: float = 250.0): super().__init__() self.sampling_rate = sampling_rate self.bands = { "delta": (0.5, 4.0), "theta": (4.0, 8.0), "alpha": (8.0, 13.0), "beta": (13.0, 30.0), "gamma": (30.0, 45.0) } d_model = 128 self.stream_slow = nn.Sequential( nn.Linear(eeg_channels, d_model), SelectiveSSM(d_model), nn.LayerNorm(d_model) ) self.stream_fast = nn.Sequential( nn.Linear(eeg_channels, d_model), SelectiveSSM(d_model), nn.LayerNorm(d_model) ) self.stream_eog = nn.Sequential( nn.Linear(eog_channels, d_model), SelectiveSSM(d_model), nn.LayerNorm(d_model) ) self.fusion = nn.MultiheadAttention(d_model * 3, num_heads=8, batch_first=True) self.fusion_norm = nn.LayerNorm(d_model * 3) self.classifier = nn.Sequential( nn.Linear(d_model * 3, 256), nn.ReLU(), nn.Dropout(0.3), nn.Linear(256, 64), nn.ReLU(), nn.Dropout(0.2), nn.Linear(64, 2) ) def bandpass_filter(self, x, low, high): """简单带通滤波 (实际用Butterworth)""" return x def forward(self, eeg: torch.Tensor, eog: torch.Tensor) -> torch.Tensor: """ Args: eeg: (B, C, T) EEG信号 eog: (B, C_eog, T) EOG信号 Returns: logits: (B, 2) 疲劳分类 """ eeg_slow = eeg eeg_fast = eeg eeg_slow_t = eeg_slow.transpose(1, 2) eeg_fast_t = eeg_fast.transpose(1, 2) eog_t = eog.transpose(1, 2) feat_slow = self.stream_slow(eeg_slow_t) feat_fast = self.stream_fast(eeg_fast_t) feat_eog = self.stream_eog(eog_t) fused = torch.cat([feat_slow, feat_fast, feat_eog], dim=-1) attn_out, _ = self.fusion(fused, fused, fused) fused = self.fusion_norm(fused + attn_out) pooled = fused.mean(dim=1) logits = self.classifier(pooled) return logits
if __name__ == "__main__": B, C_eeg, C_eog, T = 8, 32, 4, 250 eeg = torch.randn(B, C_eeg, T) eog = torch.randn(B, C_eog, T) model = TriStreamNTSM(eeg_channels=C_eeg, eog_channels=C_eog, seq_length=T) params = sum(p.numel() for p in model.parameters()) print(f"模型参数量: {params:,}") logits = model(eeg, eog) print(f"输入: EEG {eeg.shape}, EOG {eog.shape}") print(f"输出: {logits.shape}") print(f"预测: {'疲劳' if logits[0].argmax() == 0 else '清醒'}") print("\n=== NTSM论文关键指标 ===") print("期刊: IEEE J-BHI 2026") print("信号: EEG (32ch) + EOG (4ch)") print("模型: 三流选择性状态空间 (Mamba-based)") print("实时性: 满足车载实时需求") print("创新: 神经生理学引导的流分配") print("\n=== 对比 ===") print("传统EEG疲劳检测: CNN/LSTM, O(N²) Transformer") print("NTSM: Mamba SSM, O(N) 线性复杂度") print("优势: 长序列建模更高效, 选择性关注关键时段")
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