{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2026:UXQRDMBZNHTFNPTM7QJXW7BZNA","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":"36c2cee36d41ad9066c2163733c1d3f5b43daca607585f7b2b00bba0b13aaf69","cross_cats_sorted":["cs.NA"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"math.NA","submitted_at":"2026-06-05T12:01:59Z","title_canon_sha256":"9c3d04ecd38899757b3a72919e96bf14b3c527c8bbb0c264dd20dba954551656"},"schema_version":"1.0","source":{"id":"2606.07195","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2606.07195","created_at":"2026-06-08T01:04:51Z"},{"alias_kind":"arxiv_version","alias_value":"2606.07195v1","created_at":"2026-06-08T01:04:51Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2606.07195","created_at":"2026-06-08T01:04:51Z"},{"alias_kind":"pith_short_12","alias_value":"UXQRDMBZNHTF","created_at":"2026-06-08T01:04:51Z"},{"alias_kind":"pith_short_16","alias_value":"UXQRDMBZNHTFNPTM","created_at":"2026-06-08T01:04:51Z"},{"alias_kind":"pith_short_8","alias_value":"UXQRDMBZ","created_at":"2026-06-08T01:04:51Z"}],"graph_snapshots":[{"event_id":"sha256:1205a54b7e17612f3b9cdb2cf204745ed79696b7b7b0c9e2810e5b4f35932746","target":"graph","created_at":"2026-06-08T01:04:51Z","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/2606.07195/integrity.json","findings":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"Tumor perfusion and vascular properties are important determinants of a cancer's response to therapy. In this paper, we discuss the estimation of spatially varying blood flow velocities and perfusion parameters from time-resolved contrast agent concentration data. We compare a standard parabolic advection-diffusion model against a two-compartment model governed by a coupled system of hyperbolic advection-reaction equations, which is physiologically more sound. To address the inherent ill-posedness of this parameter identification problem, we employ Tikhonov regularization and derive continuous","authors_text":"Ahmed El Kaffas, Dimitre Hristov, Sebastian G\\\"otschel, Sophie Externbrink","cross_cats":["cs.NA"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"math.NA","submitted_at":"2026-06-05T12:01:59Z","title":"Adjoint-based Perfusion Estimation from Dynamic Contrast-Enhanced Ultrasound: Advection-Diffusion and Two-Compartment Models"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2606.07195","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":"sha256:4fdb3514c9c27874488a02cf9ef12326549f2d7c4f2fa4a9586ae685ca8b98df","target":"record","created_at":"2026-06-08T01:04:51Z","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":"36c2cee36d41ad9066c2163733c1d3f5b43daca607585f7b2b00bba0b13aaf69","cross_cats_sorted":["cs.NA"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"math.NA","submitted_at":"2026-06-05T12:01:59Z","title_canon_sha256":"9c3d04ecd38899757b3a72919e96bf14b3c527c8bbb0c264dd20dba954551656"},"schema_version":"1.0","source":{"id":"2606.07195","kind":"arxiv","version":1}},"canonical_sha256":"a5e111b03969e656be6cfc137b7c396821843458a25acbbc9691989b090352d8","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"a5e111b03969e656be6cfc137b7c396821843458a25acbbc9691989b090352d8","first_computed_at":"2026-06-08T01:04:51.904661Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-06-08T01:04:51.904661Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"cJ5R3A0KwaSb5WUgdsg0JUP1zQElG26ItYJGDzv2JOuwuoJ/CD1L3HVg0AVtYUxyqVxl4P0edFv38g86s3xnDQ==","signature_status":"signed_v1","signed_at":"2026-06-08T01:04:51.905387Z","signed_message":"canonical_sha256_bytes"},"source_id":"2606.07195","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:4fdb3514c9c27874488a02cf9ef12326549f2d7c4f2fa4a9586ae685ca8b98df","sha256:1205a54b7e17612f3b9cdb2cf204745ed79696b7b7b0c9e2810e5b4f35932746"],"state_sha256":"c83985ea09aa8524c6ed308a6b96c01598becce3743d183e3454bfd008ac985b"}