Refine targeted methods and freeze section structure
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@@ -62,6 +62,30 @@ EasyCom 遵循官方 Sessions 4--12/1--3 划分;十个 0.2--2.0 秒 horizon
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raw onset/offset、局部音视频和 oracle/时序消融应区分实测、历史非匹配 screen、
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仅用于分析的 privileged oracle 与待测方案。raw endpoint AP 不等同语义 EOT/INT。
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## Targeted manuscript 的 Method 固定结构
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Method 按以下三个小节展开,除非用户明确要求,不再改变这个组织顺序;具体特征和
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训练状态以代码、结果记录与 [`manuscript/targeted/main.tex`](manuscript/targeted/main.tex)
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为准。
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1. **Task and Global--Local Fusion。** 定义 5 Hz 因果截止点、十个未来 horizon 和
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background/wearer/others 输出;说明 Thinker 全局状态本身已含音视频,再定义 SWE
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的近期音频及可选视觉旁路。区分 pooled 特征的拼接聚合与 F2/F3 保留视觉 token 的
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query attention。训练范围分开写:主方案只训练 readout/局部分支/预测头;Thinker
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LoRA、限制在上层的 LoRA、预测头冻结或联合训练是参数适配控制。最后四层
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**readout** 与 LoRA 更新哪些层是两个独立维度。已归档 LoRA 结果为非匹配探索,
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不能写成层数消融或优劣定论。
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2. **Causal Partial-Tail Refresh。** 完成块进入持久历史;每个 200 ms 截止点只临时查询
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当前 2 秒块已观测的前缀,尾块不提交、不中途引入未来媒体。与 completed-only
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在同一截止点和上下文上限下配对比较;未完成实验前只称因果访问规则。
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3. **Short-Window Feature Extraction。** 默认局部音频为截止点前一秒混合波形经冻结
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Qwen 音频编码器;EgoSpeak 式 wav2vec2 卷积编码是待做的同窗口、同预测头对照,
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不能冒充已测 G+A。视觉区分最近单帧、最近一秒多帧人物框 pooled 特征、无框的
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F2 最新全画面空间 token,以及 F3 同网格位置两帧 token 经共享 GRU 后注意力聚合。
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另列一种特殊的短窗信息审计:由转写标注生成、仅含截止点之前的可见非 wearer
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活动历史,比较逐人、打乱、延迟和 OR 聚合等形式。它不是部署时可获得的视觉特征,
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也不是性能上界。F3 不是人物跟踪,F3--F2 差异也不能单独归因于运动理解。
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## 不可破坏的研究契约
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- 严格因果:任何输入音频、视频帧、人物框或归一化统计不得来自预测截止时间之后。
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@@ -143,7 +143,7 @@ committed to persistent history.}
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\section{Method}
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\label{sec:method}
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\subsection{Task and Short-Window Encoder Evidence}
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\subsection{Task and Global--Local Fusion}
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At the 5-Hz cutoff $t_n=0.2n$~s, the model observes only media available by
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$t_n$ and predicts activity at $t_n+h$, where
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@@ -152,32 +152,48 @@ horizon has three channels in fixed order: background, camera wearer, and
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aggregate others. Wearer and others may overlap; no output identifies an
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individual speaker, addressee, or semantic end of turn.
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The global feature $\vect g_n$ concatenates the final four frozen
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Qwen2.5-Omni-3B Thinker readouts and projects them to 2048 dimensions. It
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already contains audio and video context; $\G$ is not audio-free. SWE
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provides a separate short-window path so the head need not recover all
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cutoff-local detail from the integrated state. Local audio $\vect a_n$ crops
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the latest one-second mixed
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waveform \emph{before} preprocessing, runs the frozen Qwen audio encoder, and
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averages valid tokens. Optional $\vect v_n$ averages frozen vision tokens
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inside provided person boxes, then across people and valid causal 2-FPS
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frames in the latest second. This pooling has no identity or mouth-motion trajectory;
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provided boxes do not imply an online detector.
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The global representation $\vect g_n$ concatenates the final four frozen
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Qwen2.5-Omni-3B Thinker readouts and projects them to 2048 dimensions. It
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already integrates audio and video over the available context; $\G$ is not
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an audio-free baseline. Short-window encoder evidence (SWE) adds a direct,
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cutoff-aligned path for recent audio $\vect a_n$ and, when enabled, visual
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evidence $\vect v_n$. This separates the question of what the global state
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encodes from whether a small prediction head can access transient cues.
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Each enabled local feature is layer-normalized, projected to 256 dimensions,
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and paired with a validity bit. The trainable head is
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In the pooled fusion, each available local vector is layer-normalized,
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projected to 256 dimensions, and accompanied by a validity bit. The
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concatenated global and local features are passed to a layer-normalized MLP:
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\begin{equation}
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\widehat{\vect Y}_{n}=
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\operatorname{softmax}_{c}F_{\theta}
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\bigl[\vect g_n;\widetilde{\vect a}_n;m_n^a;
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\widetilde{\vect v}_n;m_n^v\bigr],
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\widehat{\vect Y}_{n,h,c}=\operatorname{softmax}_{c}
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F_{\theta}\!\left([\vect g_n;\widetilde{\vect a}_n;m_n^a;
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\widetilde{\vect v}_n;m_n^v]\right)_{h,c},
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\label{eq:fusion}
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\end{equation}
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where omitted modalities remove their terms and $F_\theta$ is a
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layer-normalized MLP with a 30-logit output. We train only the projections and
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head with the EgoSpeak multi-positive cross-entropy over causal-valid
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source--horizon pairs. The Omni and modality encoders remain frozen, so this
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is frozen-backbone adaptation rather than end-to-end training.
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where a disabled branch is omitted and $F_\theta$ produces ten sets of
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three logits. For token-preserving visual variants, $\vect v_n$ denotes
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an attention-pooled context: a query formed from $\vect g_n$ and valid
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$\vect a_n$ attends to the causal visual token set (and a learned null
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token), rather than averaging it beforehand. The resulting context and
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validity bit enter the same prediction head. We train the projections,
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visual aggregator when present, and head with the EgoSpeak multi-positive
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cross-entropy over causal-valid source--horizon pairs. The principal SWE
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configuration freezes all feature encoders and the Thinker: this is
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frozen-backbone adaptation, not task-level end-to-end training.
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We separate \emph{where} parameters are updated from \emph{which} Thinker
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layers are read. The primary comparison trains only the layer-combination
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projection, local-fusion modules, and 30-logit prediction head on cached
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frozen features. Parameter-adaptation controls instead attach low-rank
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adapters to Thinker attention projections, either across the configured
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Thinker or restricted to its upper layers; the prediction head may be
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updated jointly or held fixed to isolate representation changes. These
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controls require the same causal media, source cutoffs, supervision,
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initialization, and model-selection protocol as the frozen-head condition.
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Archived LoRA runs, including an upper-eight-layer setting, are
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exploratory and not a matched layer-scope ablation. Last-four-layer
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\emph{readout} fusion changes the head input, not the LoRA update scope;
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neither its gain nor an unmatched LoRA score establishes an adaptation
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advantage.
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\subsection{Causal Partial-Tail Refresh}
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@@ -193,18 +209,42 @@ completed-only versus PTR readouts with $\A$ on/off at an identical 8-s cap;
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the separate 2--12-s cap sweep tests context length. Those comparisons are
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pending, so PTR is a causal access rule rather than a demonstrated gain.
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\subsection{Visible-Activity Information Audit}
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\subsection{Short-Window Feature Extraction}
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To distinguish missing information from ineffective learned vision, we build
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analysis-only features from transcript-derived \emph{past} activity. At each
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cutoff, visible non-wearer participants receive two seconds of binary history
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sampled on the same 5-Hz grid. The preparation fails if its aggregate
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activity disagrees with the released target. We compare: (i) visibility with
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activity zeroed, (ii) per-person histories, (iii) identities shuffled while
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preserving active-person counts at every lag, (iv) histories delayed by one
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second, and (v) one OR-pooled aggregate-visible history. These conditions
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never expose future activity, but their speech labels make them privileged
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diagnostics, not deployable features or upper bounds.
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We define every local observation by its prediction cutoff, before applying
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any encoder-specific preprocessing. The default audio branch encodes the
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mixed waveform in $[t_n-1\,\mathrm{s},t_n)$ with the frozen Qwen2.5-Omni
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audio encoder and averages valid output tokens. A wav2vec~2.0 convolutional
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audio representation, as used by EgoSpeak \cite{kim2025egospeak}, is an
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encoder-choice control; it must use the same one-second input interval and
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forecasting head before differences can be attributed to the encoder. It is
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not the source of the reported $\G+\A$ result.
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For vision, a single-frame variant uses the latest frame strictly before
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$t_n$; the pooled person-crop variant averages frozen Qwen vision tokens
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within provided boxes, across visible people, and over valid 2-FPS frames
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in the preceding second. These pooled features summarize appearance but
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discard person identity and explicit motion. Boxes are dataset-provided,
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not predictions from an evaluated online detector. Two no-box full-frame
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alternatives retain the post-merger spatial-token grid: F2 lets the
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global--audio query attend to the latest causal frame; F3 first encodes up
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to two observations at each matching grid location in chronological order
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with a shared GRU, then applies the same query to the resulting grid. F3
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links image coordinates, not people or tracks. Its difference from F2
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confounds additional history and temporal capacity, so it cannot alone
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establish a motion or speaker-grounding mechanism. Empty or unavailable
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local evidence is indicated by the validity masks, never filled with a
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future observation.
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As a distinct, privileged short-window feature, we also derive visible
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non-wearer speech activity from transcript annotations \emph{before} each
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cutoff. Each visible participant contributes a two-second binary history
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on the 5-Hz grid. We test visibility-only, per-person, identity-shuffled,
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one-second-delayed, and OR-pooled aggregate histories to ask which timely
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activity information a learned visual branch would need to recover.
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Although strictly past-only, these annotations are not available from raw
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media at inference; this is an information audit, not a deployable feature
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or a performance upper bound.
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\input{tables_compact}
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% Historical full-precision table layouts retained as source audit only.
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