{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2013:3RVZFJD7XFHIWC5OIBGNXTGWEM","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":"d0f4699d1f8b461e212200c880e5459e85756c2487e1c345b321e82e6e56be89","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.data-an","submitted_at":"2013-04-25T08:59:12Z","title_canon_sha256":"dd0825b46d8c05b37730564bb4ba99a8519071139b9997585da5ff9af3aa5669"},"schema_version":"1.0","source":{"id":"1304.6836","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1304.6836","created_at":"2026-05-18T02:52:58Z"},{"alias_kind":"arxiv_version","alias_value":"1304.6836v1","created_at":"2026-05-18T02:52:58Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1304.6836","created_at":"2026-05-18T02:52:58Z"},{"alias_kind":"pith_short_12","alias_value":"3RVZFJD7XFHI","created_at":"2026-05-18T12:27:32Z"},{"alias_kind":"pith_short_16","alias_value":"3RVZFJD7XFHIWC5O","created_at":"2026-05-18T12:27:32Z"},{"alias_kind":"pith_short_8","alias_value":"3RVZFJD7","created_at":"2026-05-18T12:27:32Z"}],"graph_snapshots":[{"event_id":"sha256:6c11724013cb39b417f6d21b084271049fbec4ed9d44806d8d4fd80430cf27f1","target":"graph","created_at":"2026-05-18T02:52:58Z","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"},"paper":{"abstract_excerpt":"Data assimilation method consists in combining all available pieces of information about a system to obtain optimal estimates of initial states. The different sources of information are weighted according to their accuracy by the means of error covariance matrices. Our purpose here is to evaluate the efficiency of variational data assimilation for the xenon induced oscillations forecasts in nuclear cores. In this paper we focus on the comparison between 3DVAR schemes with optimised background error covariance matrix B and a 4DVAR scheme. Tests were made in twin experiments using a simulation c","authors_text":"Ang\\'elique Pon\\c{c}ot, Bertrand Bouriquet, Jean-Philippe Argaud, Olivier Thual, Patrick Erhard, Serge Gratton","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.data-an","submitted_at":"2013-04-25T08:59:12Z","title":"Variational Assimilation for Xenon Dynamical Forecasts in Neutronic using Advanced Background Error Covariance Matrix"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1304.6836","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":"sha256:061ae61160637b5492027f1a873c521f9a4848d028aa3eb7b941614835e7cc1a","target":"record","created_at":"2026-05-18T02:52:58Z","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":"d0f4699d1f8b461e212200c880e5459e85756c2487e1c345b321e82e6e56be89","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.data-an","submitted_at":"2013-04-25T08:59:12Z","title_canon_sha256":"dd0825b46d8c05b37730564bb4ba99a8519071139b9997585da5ff9af3aa5669"},"schema_version":"1.0","source":{"id":"1304.6836","kind":"arxiv","version":1}},"canonical_sha256":"dc6b92a47fb94e8b0bae404cdbccd623019c2fa029add29c27ab0882f2d48ba3","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"dc6b92a47fb94e8b0bae404cdbccd623019c2fa029add29c27ab0882f2d48ba3","first_computed_at":"2026-05-18T02:52:58.485690Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T02:52:58.485690Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"9BuknEmNFReesNf3JUnJjZ9jrR09HiFGTChe/OGuUgo83cpxIcFxhAy4uJAYeVYURPUqBKqAko/yJrJxQuqiAA==","signature_status":"signed_v1","signed_at":"2026-05-18T02:52:58.486149Z","signed_message":"canonical_sha256_bytes"},"source_id":"1304.6836","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:061ae61160637b5492027f1a873c521f9a4848d028aa3eb7b941614835e7cc1a","sha256:6c11724013cb39b417f6d21b084271049fbec4ed9d44806d8d4fd80430cf27f1"],"state_sha256":"7ce8e719f85dece1e821093161a7ddbf446561403311ba6833e5f019ccb6f02a"}