L1 ⚛ L1-269 ⊙ Testnet

Duct Acoustics — wave propagation in ducts / silencers

Acoustics · Modal transmission in non-uniform ducts

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⬇ L1-269.md

# ⚛ L1 Principle — Duct Acoustics — wave propagation in ducts / silencers **ID:** `L1-269` · **Status:** ⊙ Testnet (genesis catalog) > **🌐 Domain:** Acoustics — *Modal transmission in non-uniform ducts* > **🎯 Problem class:** linear inverse · **🧮 Solution space:** modal amplitudes 1D > **📡 Carrier:** acoustic · **🌫 Noise:** gaussian > **⚖ Difficulty (δ):** 3 · **⛓ Block:** 41554050 --- ## 🧠 1. Introduction **Duct Acoustics — wave propagation in ducts / silencers** is a **linear inverse problem** whose unknown lives in **modal amplitudes 1D** space, within the **Modal transmission in non-uniform ducts** sub-domain of **Acoustics**. Measurements consist of acoustic pressure waves recorded by transducers via a **pressure in duct** sensing mechanism. The forward operator applies, in order: L · modal decomp operator; L · transfer matrix operator; L · impedance BC operator; integration over a band of frequencies. Observations are corrupted by additive Gaussian noise. Conditional stability; mismatch parameters dominate at Omega bounds. ## ⚙ 2. Forward Model Physical chain: **x** → L · modal decomp → L · transfer matrix → L · impedance BC → Frequency integration → **y** (detector). ``` y = ∫dω `L.impedance_BC` `L.transfer_matrix` `L.modal_decomp` x + n, n ~ 𝒩(0, σ²) ``` **Measurement DAG:** | Primitive | What it does | |---|---| | `L.modal_decomp` | L · modal decomp operator | | `L.transfer_matrix` | L · transfer matrix operator | | `L.impedance_BC` | L · impedance bc operator | | `int.frequency` | Integration over a band of frequencies | ## 🔬 3. Physics Fingerprint | Property | Value | |---|---| | Domain | Acoustics | | Sub domain | Modal transmission in non-uniform ducts | | Carrier | acoustic | | Problem class | linear_inverse | | Solution space | modal_amplitudes_1D | | Noise model | gaussian | | Integration axis | frequency | | Difficulty delta | 3 | | L dag | 3 | ## 📡 4. Measurement Model Conditional stability; mismatch parameters dominate at Omega bounds. | Metric | Value | |---|---| | Metric | PSNR_dB | | Secondary | SSIM | ## 📏 5. Operating Range (Ω) **Center problem class:** `duct_transfer_matrix` · **Forward operator:** `duct_transfer_matrix_forward` **Center point:** | Parameter | Unit | Value | |---|---|---| | L m | m | 1 | | M mach | — | 0.1 | | Snr db | dB | 30 | | N modes | — | 8 | | Freq hz | Hz | 1000 | | N probes | — | 8 | | Flow mach error | — | 0 | | Duct geometry error | — | 0 | | Liner impedance error | — | 0 | **Allowed bounds:** | Parameter | Unit | Range | |---|---|---| | L m | m | 0.1 – 20 | | M mach | — | 0.0 – 0.8 | | Snr db | dB | 0 – 40 | | N modes | — | 1 – 32 | | Freq hz | Hz | 50 – 10000 | | N probes | — | 2 – 64 | | Flow mach error | — | 0.0 – 0.1 | | Duct geometry error | — | 0.0 – 0.05 | | Liner impedance error | — | 0.0 – 0.3 | ## 🎯 6. Tolerance (ε) **Center tolerance:** 23.0 | Metric | Range | |---|---| | Psnr db | 10.0 – 45.0 | ## ⚖ 7. Hardness Function Hardness scales as **`epsilon_fn`** on **PSNR_dB**, with κ = `240` and δ = `3`. ## 💾 8. Reference Dataset - **primary** · weight 1.0 · IPFS _(not pinned yet)_ ## 9. On-chain Registration - **Chain hash:** `0xac80efe9fe6428c69aa301b45fa50b19aef2242caa1d0655455a91c5cb479297` - **Chain tx hash:** `0x540ead0642df71e750eebe3333794c903f5a4175ab7040f8c9df01397b6805ef` - **Chain block:** `41554050` --- ## File Mapping This bundle consists of: `L1-269.md`, `L1-269.json`. | File | Role | How to regenerate | |------|------|-------------------| | `L1-269.md` | Source of truth — edit this | Human or LLM | | `L1-269.json` | Structured metadata for the registry | LLM regenerates from the sections above | **Prompt for your LLM after editing this Markdown:** > Read the attached Markdown. Regenerate the sibling `.json` so every field matches. > Preserve the schema documented in the rows above. > Output each file in its own fenced code block tagged with the filename. > Output only the JSON object. _This Markdown was auto-synthesized from the catalog row for `L1-269`._ _Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._

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Read the attached Markdown (L1-269.md).
Regenerate L1-269.json so every field matches the Markdown.
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L2-269-001 Duct Acoustics — wave propagation in ducts / silencers Mismatch-Only Spec

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📋 JSON metadata

{
  "artifact_id": "L1-269",
  "chain_block": 41554050,
  "chain_hash": "0xac80efe9fe6428c69aa301b45fa50b19aef2242caa1d0655455a91c5cb479297",
  "chain_tx_hash": "0x540ead0642df71e750eebe3333794c903f5a4175ab7040f8c9df01397b6805ef",
  "domain": "Acoustics",
  "hardness_fn": {
    "delta": 3,
    "kappa": 240,
    "metric": "PSNR_dB",
    "type": "epsilon_fn"
  },
  "initiator_dataset": [
    {
      "ipfs_cid": null,
      "license_hash": null,
      "name": "primary",
      "weight": 1.0
    }
  ],
  "layer": "L1",
  "observable_profile": {
    "metric": "PSNR_dB",
    "regime": "Conditional stability; mismatch parameters dominate at Omega bounds.",
    "secondary": "SSIM"
  },
  "physics_fingerprint": {
    "L_DAG": 3.0,
    "carrier": "acoustic",
    "difficulty_delta": 3,
    "domain": "Acoustics",
    "integration_axis": "frequency",
    "noise_model": "gaussian",
    "primitives": [
      "L.modal_decomp",
      "L.transfer_matrix",
      "L.impedance_BC",
      "int.frequency"
    ],
    "problem_class": "linear_inverse",
    "sensing_mechanism": "pressure_in_duct",
    "solution_space": "modal_amplitudes_1D",
    "sub_domain": "Modal transmission in non-uniform ducts",
    "title": "Duct Acoustics \u2014 wave propagation in ducts / silencers"
  },
  "size_tiers": {
    "allowed_forward_operators": [
      "duct_transfer_matrix_forward"
    ],
    "allowed_omega_dimensions": [
      "N_modes",
      "L_m",
      "N_probes",
      "freq_Hz",
      "M_mach",
      "SNR_dB",
      "liner_impedance_error",
      "duct_geometry_error",
      "flow_mach_error",
      "liner_impedance_error",
      "duct_geometry_error",
      "flow_mach_error"
    ],
    "allowed_problem_classes": [
      "duct_transfer_matrix"
    ],
    "center_spec": {
      "epsilon_fn_center": "23.0",
      "forward_operator": "duct_transfer_matrix_forward",
      "input_format": "measurement_only",
      "omega": {
        "L_m": 1.0,
        "M_mach": 0.1,
        "N_modes": 8,
        "N_probes": 8,
        "SNR_dB": 30,
        "duct_geometry_error": 0.0,
        "flow_mach_error": 0.0,
        "freq_Hz": 1000,
        "liner_impedance_error": 0.0
      },
      "problem_class": "duct_transfer_matrix"
    },
    "epsilon_bounds": {
      "psnr_db": [
        10.0,
        45.0
      ]
    },
    "omega_bounds": {
      "L_m": [
        0.1,
        20
      ],
      "M_mach": [
        0.0,
        0.8
      ],
      "N_modes": [
        1,
        32
      ],
      "N_probes": [
        2,
        64
      ],
      "SNR_dB": [
        0,
        40
      ],
      "duct_geometry_error": [
        0.0,
        0.05
      ],
      "flow_mach_error": [
        0.0,
        0.1
      ],
      "freq_Hz": [
        50,
        10000
      ],
      "liner_impedance_error": [
        0.0,
        0.3
      ]
    }
  },
  "staked_pwm": 0.0,
  "status": "testnet",
  "sub_domain": "Modal transmission in non-uniform ducts",
  "title": "Duct Acoustics \u2014 wave propagation in ducts / silencers"
}

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