{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2021:ZOSTSWUMD44FKDBH3HUE67BVD2","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":"c753de50e0f8fbe0d152157e812c0f9f532cbdc84334d67495619bd92d5c55ee","cross_cats_sorted":["cs.NA"],"license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","primary_cat":"math.NA","submitted_at":"2021-04-09T21:45:26Z","title_canon_sha256":"c7dfb3942157722b5a09ff30482a92450b011697c588f302e204e6c9f5c7f5b3"},"schema_version":"1.0","source":{"id":"2104.04618","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2104.04618","created_at":"2026-07-05T03:37:42Z"},{"alias_kind":"arxiv_version","alias_value":"2104.04618v2","created_at":"2026-07-05T03:37:42Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2104.04618","created_at":"2026-07-05T03:37:42Z"},{"alias_kind":"pith_short_12","alias_value":"ZOSTSWUMD44F","created_at":"2026-07-05T03:37:42Z"},{"alias_kind":"pith_short_16","alias_value":"ZOSTSWUMD44FKDBH","created_at":"2026-07-05T03:37:42Z"},{"alias_kind":"pith_short_8","alias_value":"ZOSTSWUM","created_at":"2026-07-05T03:37:42Z"}],"graph_snapshots":[{"event_id":"sha256:63f1fa12362edf17b3e89bec2bb386baa3996730a26c99474cbeca6b83544f0b","target":"graph","created_at":"2026-07-05T03:37:42Z","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/2104.04618/integrity.json","findings":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"The boundary element method is an efficient algorithm for simulating acoustic propagation through homogeneous objects embedded in free space. The conditioning of the system matrix strongly depends on physical parameters such as density, wavespeed and frequency. In particular, high contrast in density and wavespeed across a material interface leads to an ill-conditioned discretisation matrix. Therefore, the convergence of Krylov methods to solve the linear system is slow. Here, specialised boundary integral formulations are designed for the case of acoustic scattering at high-contrast media. Th","authors_text":"Elwin van 't Wout, Nader Saffari, Pierre G\\'elat, Seyyed R. Haqshenas, Timo Betcke","cross_cats":["cs.NA"],"headline":"","license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","primary_cat":"math.NA","submitted_at":"2021-04-09T21:45:26Z","title":"Boundary integral formulations for acoustic modelling of high-contrast media"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2104.04618","kind":"arxiv","version":2},"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:d91fb94bcef2f305c70c836d58d6475c8a0dc8523e351a53e33e6d27cc93ede0","target":"record","created_at":"2026-07-05T03:37:42Z","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":"c753de50e0f8fbe0d152157e812c0f9f532cbdc84334d67495619bd92d5c55ee","cross_cats_sorted":["cs.NA"],"license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","primary_cat":"math.NA","submitted_at":"2021-04-09T21:45:26Z","title_canon_sha256":"c7dfb3942157722b5a09ff30482a92450b011697c588f302e204e6c9f5c7f5b3"},"schema_version":"1.0","source":{"id":"2104.04618","kind":"arxiv","version":2}},"canonical_sha256":"cba5395a8c1f38550c27d9e84f7c351ebbc99db38f784aaf5eb29efab3366d9d","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"cba5395a8c1f38550c27d9e84f7c351ebbc99db38f784aaf5eb29efab3366d9d","first_computed_at":"2026-07-05T03:37:42.156618Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-07-05T03:37:42.156618Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"POhtvobqKRmnmXk9JqBkE8ZT2bh/0wh6OZrUjuRxMwUhOU1ZBBKHbeyY+K8jyx6oemBwMPTLOdtJoS4YpZYgAg==","signature_status":"signed_v1","signed_at":"2026-07-05T03:37:42.157068Z","signed_message":"canonical_sha256_bytes"},"source_id":"2104.04618","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:d91fb94bcef2f305c70c836d58d6475c8a0dc8523e351a53e33e6d27cc93ede0","sha256:63f1fa12362edf17b3e89bec2bb386baa3996730a26c99474cbeca6b83544f0b"],"state_sha256":"7293737461cce0c0d193ba77fe088223b8104312eaa8783b0806a28afc821e1d"}