Pith Number

pith:SASQI4JD

pith:2026:SASQI4JDICNZVPHMX5LZF4VLKT

not attested not anchored not stored refs resolved

Instantaneous Spectra Analysis of Pulse Series -- Application to Lung Sounds with Abnormalities

Fumihiko Ishiyama

Replacing periodic boundary conditions with linear extrapolation enables instantaneous spectra of non-periodic pulse series such as lung crackles.

arxiv:2602.03680 v2 · 2026-02-03 · physics.soc-ph · cs.SD

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4 Citations open

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The bundle contains the canonical record plus signed events. A mirror can host it anywhere and recompute the same current state with the deterministic merge algorithm.

Claims

C1strongest claim

We previously proposed to replace this condition with 'Linear eXtrapolation Condition (LXC),' which does not require periodicity. This feature makes instantaneous spectra analysis of pulse series available, which replaces the short time Fourier transform (STFT).

C2weakest assumption

That the Linear eXtrapolation Condition accurately captures the underlying signal without introducing artifacts or losing information compared to standard methods, particularly for random pulse series like crackles.

C3one line summary

A linear extrapolation boundary condition replaces periodicity assumptions in Fourier analysis, allowing instantaneous spectra of pulse series like abnormal lung sounds.

References

13 extracted · 13 resolved · 0 Pith anchors

[1] Refreshing idea on Fourier analysis, 2025 · doi:10.1109/cspa64953.2025.10933386

[2] Maximum entropy method without false peak s with exact numerical equation, 2020 · doi:10.1088/1742-6596/1438/1/012031

[3] On periodicity in series of related terms, 1931

[4] Descriptor: Hear t and Lung Sounds Dataset Recorded From a Clinical Manikin Using Digital Stet hoscope 9 (HLS-CMDS), 2025 · doi:10.1109/ieeedata.2025.3566012

[5] Nonlinear trend of COVID-19 infection tim e series, 2023 · doi:10.1587/nolta.14.165

Formal links

1 machine-checked theorem link

Receipt and verification

First computed	2026-05-17T23:39:16.398403Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

9025047123409b9abcecbf5792f2ab54ff80767497ac836f33e0cd076426eb68

Aliases

arxiv: 2602.03680 · arxiv_version: 2602.03680v2 · doi: 10.48550/arxiv.2602.03680 · pith_short_12: SASQI4JDICNZ · pith_short_16: SASQI4JDICNZVPHM · pith_short_8: SASQI4JD

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Verify this Pith Number yourself

curl -sH 'Accept: application/ld+json' https://pith.science/pith/SASQI4JDICNZVPHMX5LZF4VLKT \
  | jq -c '.canonical_record' \
  | python3 -c "import sys,json,hashlib; b=json.dumps(json.loads(sys.stdin.read()), sort_keys=True, separators=(',',':'), ensure_ascii=False).encode(); print(hashlib.sha256(b).hexdigest())"
# expect: 9025047123409b9abcecbf5792f2ab54ff80767497ac836f33e0cd076426eb68

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "ab331a4a447d66c070d1ef01f8c5b30a480191f27d143181fd40681fc581e2c4",
    "cross_cats_sorted": [
      "cs.SD"
    ],
    "license": "http://creativecommons.org/licenses/by/4.0/",
    "primary_cat": "physics.soc-ph",
    "submitted_at": "2026-02-03T16:01:44Z",
    "title_canon_sha256": "c018f4591fe6f37e97c695771458a4aa317207075c5e95fb30456d5f8732cf0c"
  },
  "schema_version": "1.0",
  "source": {
    "id": "2602.03680",
    "kind": "arxiv",
    "version": 2
  }
}