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wifi-ruview/examples/research-sota
rUv 3d3d54d523 research(R3.1): physics-informed env prediction at raw-CSI level — NEGATIVE (architecture-error) (#723)
R3's 'next research lever' was: use R6.1 forward operator + room map
to predict env_sig without labelled examples in the new room. R6.1
shipped (tick 18); this tick implements the prediction.

Result: at raw-CSI level, all three approaches collapse to chance.

| Configuration                          | 1-shot K-NN |
|----------------------------------------|------------:|
| Within-room baseline                   |    100%    |
| Cross-room RAW                         |     10%    | (chance)
| Cross-room labelled MERIDIAN (oracle)  |     10%    | (chance)
| Cross-room physics-informed            |     10%    | (chance)

Even the LABELLED oracle fails at raw-CSI level -- which is the
diagnostic. The cross-room problem at raw-CSI level is fundamentally
harder than at the AETHER embedding level (R3 tick 12) because
position-dependent within-room variance dominates per-subject
signature when invariantisation hasn't been done.

Corrected architecture:
  raw CSI -> AETHER embedding -> physics-informed env subtraction -> K-NN
  (apply physics prediction at embedding level, NOT raw level)

AETHER does position-invariance; predicted-env then removes only the
room-shift component.

THIS IS THE LOOP'S THIRD KIND OF NEGATIVE RESULT:
1. Missing-tool (revisitable):  R12 NEGATIVE -> R12 PABS POSITIVE
   (tool became available later, approach worked)
2. Physics-floor (permanent):   R13 contactless BP
   (hard 5 dB wall; no tool changes this)
3. Architecture-error (correctable): R3.1 (this tick)
   (right idea, wrong application level; corrected architecture
   explicit but not yet implemented)

Categorising negatives by resolution path is itself a research
contribution.

Surfaces an architecture error BEFORE implementation. A future
engineer attempting 'subtract predicted env from raw CSI' would
waste weeks; R3.1 documents the failure path.

Composes:
- R3 POSITIVE confirmed indirectly: raw-level failure shows why R3
  operated at embedding level
- R6.1 operator is correct; application level was wrong
- R12 PABS works at raw level because no cross-room transfer needed
- R13 vs R3.1: two different kinds of negative

Honest scope: weak per-subject signature (body-size only), 3 positions
per room, geometry-specific. Richer biometric input or per-position-
clustering might partially rescue raw-level but defeats the no-label
spirit.

Coordination: ticks/tick-20.md, no PROGRESS.md edit.
2026-05-22 04:04:38 -04:00
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