{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2023:MLSCCG6HKSKS6XRKONNTP3XT2M","short_pith_number":"pith:MLSCCG6H","canonical_record":{"source":{"id":"2309.15415","kind":"arxiv","version":1},"metadata":{"license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","primary_cat":"eess.SP","submitted_at":"2023-09-27T05:43:37Z","cross_cats_sorted":[],"title_canon_sha256":"0092cc12f6b1bbca7d3dd1ea540a3744198946ddbd72f769ee9d777827e5def9","abstract_canon_sha256":"37cf69d139e67ba72771d3018c3b098b4b4023672eec00b25b752b16bea30784"},"schema_version":"1.0"},"canonical_sha256":"62e4211bc754952f5e2a735b37eef3d32569057d3fc0dd798e9024c8d86674b6","source":{"kind":"arxiv","id":"2309.15415","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2309.15415","created_at":"2026-07-05T06:54:45Z"},{"alias_kind":"arxiv_version","alias_value":"2309.15415v1","created_at":"2026-07-05T06:54:45Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2309.15415","created_at":"2026-07-05T06:54:45Z"},{"alias_kind":"pith_short_12","alias_value":"MLSCCG6HKSKS","created_at":"2026-07-05T06:54:45Z"},{"alias_kind":"pith_short_16","alias_value":"MLSCCG6HKSKS6XRK","created_at":"2026-07-05T06:54:45Z"},{"alias_kind":"pith_short_8","alias_value":"MLSCCG6H","created_at":"2026-07-05T06:54:45Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2023:MLSCCG6HKSKS6XRKONNTP3XT2M","target":"record","payload":{"canonical_record":{"source":{"id":"2309.15415","kind":"arxiv","version":1},"metadata":{"license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","primary_cat":"eess.SP","submitted_at":"2023-09-27T05:43:37Z","cross_cats_sorted":[],"title_canon_sha256":"0092cc12f6b1bbca7d3dd1ea540a3744198946ddbd72f769ee9d777827e5def9","abstract_canon_sha256":"37cf69d139e67ba72771d3018c3b098b4b4023672eec00b25b752b16bea30784"},"schema_version":"1.0"},"canonical_sha256":"62e4211bc754952f5e2a735b37eef3d32569057d3fc0dd798e9024c8d86674b6","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-07-05T06:54:45.589185Z","signature_b64":"EWba6KeGWk6/RSQQfe9Cxa+K2t9bfqu8c96Gwctm2tuiTJy1isiCBONoimE+TJVOPPkcJWQf+kDFui/Mlf7CDQ==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"62e4211bc754952f5e2a735b37eef3d32569057d3fc0dd798e9024c8d86674b6","last_reissued_at":"2026-07-05T06:54:45.588741Z","signature_status":"signed_v1","first_computed_at":"2026-07-05T06:54:45.588741Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"2309.15415","source_version":1,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-07-05T06:54:45Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"e9sK7sjYDOcER+o02AWOFPwRqPh7Ye5ZHBkTI6vhnZ4EDiIS9wtlsq/BmYBiFJu2NDi5tEM0l4X5T/LsdrKUAQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-07-06T07:34:23.943962Z"},"content_sha256":"03ea31999120495b7705bd5dec909d8beff077a0eafcf5912302ba56f08ffc02","schema_version":"1.0","event_id":"sha256:03ea31999120495b7705bd5dec909d8beff077a0eafcf5912302ba56f08ffc02"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2023:MLSCCG6HKSKS6XRKONNTP3XT2M","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Formation Wing-Beat Modulation (FWM): A Tool for Quantifying Bird Flocks Using Radar Micro-Doppler Signals","license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","headline":"","cross_cats":[],"primary_cat":"eess.SP","authors_text":"Deren Li, Deyong Kong, Jiangkun Gong, Jun Yan, Ruizhi Chen","submitted_at":"2023-09-27T05:43:37Z","abstract_excerpt":"Radar echoes from bird flocks contain modulation signals, which we find are produced by the flapping gaits of birds in the flock, resulting in a group of spectral peaks with similar amplitudes spaced at a specific interval. We call this the formation wing-beat modulation (FWM) effect. FWM signals are micro-Doppler modulated by flapping wings and are related to the bird number, wing-beat frequency, and flight phasing strategy. Our X-band radar data show that FWM signals exist in radar signals of a seagull flock, providing tools for quantifying the bird number and estimating the mean wingbeat ra"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2309.15415","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2309.15415/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"},"verdict_id":null},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-07-05T06:54:45Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"8bQFinaG9iMAW33rJtePePmdXVbzIhrWu9KXAxiO4Go8kJ1hEjLBTf5ipXvPA9tyuVjLDpVHhoGxhy4XGAsHAQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-07-06T07:34:23.944347Z"},"content_sha256":"f7664dbd56eb4e0f1a7d038d55779fc4d2117d8895629ffc0d16742119fe0a62","schema_version":"1.0","event_id":"sha256:f7664dbd56eb4e0f1a7d038d55779fc4d2117d8895629ffc0d16742119fe0a62"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/MLSCCG6HKSKS6XRKONNTP3XT2M/bundle.json","state_url":"https://pith.science/pith/MLSCCG6HKSKS6XRKONNTP3XT2M/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/MLSCCG6HKSKS6XRKONNTP3XT2M/bundle.json","status":"primary"}],"public_keys":[{"key_id":"pith-v1-2026-05","algorithm":"ed25519","format":"raw","public_key_b64":"stVStoiQhXFxp4s2pdzPNoqVNBMojDU/fJ2db5S3CbM=","public_key_hex":"b2d552b68890857171a78b36a5dccf368a953413288c353f7c9d9d6f94b709b3","fingerprint_sha256_b32_first128bits":"RVFV5Z2OI2J3ZUO7ERDEBCYNKS","fingerprint_sha256_hex":"8d4b5ee74e4693bcd1df2446408b0d54","rotates_at":null,"url":"https://pith.science/pith-signing-key.json","notes":"Pith uses this Ed25519 key to sign canonical record SHA-256 digests. Verify with: ed25519_verify(public_key, message=canonical_sha256_bytes, signature=base64decode(signature_b64))."}],"merge_version":"pith-open-graph-merge-v1","built_at":"2026-07-06T07:34:23Z","links":{"resolver":"https://pith.science/pith/MLSCCG6HKSKS6XRKONNTP3XT2M","bundle":"https://pith.science/pith/MLSCCG6HKSKS6XRKONNTP3XT2M/bundle.json","state":"https://pith.science/pith/MLSCCG6HKSKS6XRKONNTP3XT2M/state.json","well_known_bundle":"https://pith.science/.well-known/pith/MLSCCG6HKSKS6XRKONNTP3XT2M/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2023:MLSCCG6HKSKS6XRKONNTP3XT2M","merge_version":"pith-open-graph-merge-v1","event_count":2,"valid_event_count":2,"invalid_event_count":0,"equivocation_count":0,"current":{"canonical_record":{"metadata":{"abstract_canon_sha256":"37cf69d139e67ba72771d3018c3b098b4b4023672eec00b25b752b16bea30784","cross_cats_sorted":[],"license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","primary_cat":"eess.SP","submitted_at":"2023-09-27T05:43:37Z","title_canon_sha256":"0092cc12f6b1bbca7d3dd1ea540a3744198946ddbd72f769ee9d777827e5def9"},"schema_version":"1.0","source":{"id":"2309.15415","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2309.15415","created_at":"2026-07-05T06:54:45Z"},{"alias_kind":"arxiv_version","alias_value":"2309.15415v1","created_at":"2026-07-05T06:54:45Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2309.15415","created_at":"2026-07-05T06:54:45Z"},{"alias_kind":"pith_short_12","alias_value":"MLSCCG6HKSKS","created_at":"2026-07-05T06:54:45Z"},{"alias_kind":"pith_short_16","alias_value":"MLSCCG6HKSKS6XRK","created_at":"2026-07-05T06:54:45Z"},{"alias_kind":"pith_short_8","alias_value":"MLSCCG6H","created_at":"2026-07-05T06:54:45Z"}],"graph_snapshots":[{"event_id":"sha256:f7664dbd56eb4e0f1a7d038d55779fc4d2117d8895629ffc0d16742119fe0a62","target":"graph","created_at":"2026-07-05T06:54:45Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"graph_snapshot":{"author_claims":{"count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","strong_count":0},"builder_version":"pith-number-builder-2026-05-17-v1","claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"integrity":{"available":true,"clean":true,"detectors_run":[],"endpoint":"/pith/2309.15415/integrity.json","findings":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"Radar echoes from bird flocks contain modulation signals, which we find are produced by the flapping gaits of birds in the flock, resulting in a group of spectral peaks with similar amplitudes spaced at a specific interval. We call this the formation wing-beat modulation (FWM) effect. FWM signals are micro-Doppler modulated by flapping wings and are related to the bird number, wing-beat frequency, and flight phasing strategy. Our X-band radar data show that FWM signals exist in radar signals of a seagull flock, providing tools for quantifying the bird number and estimating the mean wingbeat ra","authors_text":"Deren Li, Deyong Kong, Jiangkun Gong, Jun Yan, Ruizhi Chen","cross_cats":[],"headline":"","license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","primary_cat":"eess.SP","submitted_at":"2023-09-27T05:43:37Z","title":"Formation Wing-Beat Modulation (FWM): A Tool for Quantifying Bird Flocks Using Radar Micro-Doppler Signals"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2309.15415","kind":"arxiv","version":1},"verdict":{"created_at":null,"id":null,"model_set":{},"one_line_summary":"","pipeline_version":null,"pith_extraction_headline":"","strongest_claim":"","weakest_assumption":""}},"verdict_id":null}}],"author_attestations":[],"timestamp_anchors":[],"storage_attestations":[],"citation_signatures":[],"replication_records":[],"corrections":[],"mirror_hints":[],"record_created":{"event_id":"sha256:03ea31999120495b7705bd5dec909d8beff077a0eafcf5912302ba56f08ffc02","target":"record","created_at":"2026-07-05T06:54:45Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"attestation_state":"computed","canonical_record":{"metadata":{"abstract_canon_sha256":"37cf69d139e67ba72771d3018c3b098b4b4023672eec00b25b752b16bea30784","cross_cats_sorted":[],"license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","primary_cat":"eess.SP","submitted_at":"2023-09-27T05:43:37Z","title_canon_sha256":"0092cc12f6b1bbca7d3dd1ea540a3744198946ddbd72f769ee9d777827e5def9"},"schema_version":"1.0","source":{"id":"2309.15415","kind":"arxiv","version":1}},"canonical_sha256":"62e4211bc754952f5e2a735b37eef3d32569057d3fc0dd798e9024c8d86674b6","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"62e4211bc754952f5e2a735b37eef3d32569057d3fc0dd798e9024c8d86674b6","first_computed_at":"2026-07-05T06:54:45.588741Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-07-05T06:54:45.588741Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"EWba6KeGWk6/RSQQfe9Cxa+K2t9bfqu8c96Gwctm2tuiTJy1isiCBONoimE+TJVOPPkcJWQf+kDFui/Mlf7CDQ==","signature_status":"signed_v1","signed_at":"2026-07-05T06:54:45.589185Z","signed_message":"canonical_sha256_bytes"},"source_id":"2309.15415","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:03ea31999120495b7705bd5dec909d8beff077a0eafcf5912302ba56f08ffc02","sha256:f7664dbd56eb4e0f1a7d038d55779fc4d2117d8895629ffc0d16742119fe0a62"],"state_sha256":"4e4fcd6aa1eed055b027eb17d5ab793cf58da987b3f74593ca6ee7baac65f7e6"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"6RxCurSfxJNLBJCnv2PMQk1IRrlrwo96jVpSIaAqyndrG3y7ft98PyOUNLMK+ZYnUTvT8Sp+YRKbylUmHEqgAg==","signed_message":"bundle_sha256_bytes","signed_at":"2026-07-06T07:34:23.946276Z","bundle_sha256":"92336dc3810fffc8d4a7a25c9fbb8dc41e17f494348fcfa28fe414531584a941"}}