{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2021:R5KQMOF7BYPFNOQIMWCVY7PFI7","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":"15ff294f71a544f9b36f57e7cd6b6942b148c328e4243cb9e9fab44b51181b7b","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"eess.SP","submitted_at":"2021-08-26T16:50:27Z","title_canon_sha256":"b8b5ccbdc18f209fb537195ae3361f51a9efd62fb7ead16c12b4c21af94f1adf"},"schema_version":"1.0","source":{"id":"2108.11902","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2108.11902","created_at":"2026-07-05T03:09:10Z"},{"alias_kind":"arxiv_version","alias_value":"2108.11902v1","created_at":"2026-07-05T03:09:10Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2108.11902","created_at":"2026-07-05T03:09:10Z"},{"alias_kind":"pith_short_12","alias_value":"R5KQMOF7BYPF","created_at":"2026-07-05T03:09:10Z"},{"alias_kind":"pith_short_16","alias_value":"R5KQMOF7BYPFNOQI","created_at":"2026-07-05T03:09:10Z"},{"alias_kind":"pith_short_8","alias_value":"R5KQMOF7","created_at":"2026-07-05T03:09:10Z"}],"graph_snapshots":[{"event_id":"sha256:7fcb59ac6ff497219c359dcb04144d1a3b4bbd8bc8f0df2c909c3d9cc76725b3","target":"graph","created_at":"2026-07-05T03:09:10Z","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/2108.11902/integrity.json","findings":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"With the deep integration between the unmanned aerial vehicle (UAV) and wireless communication, UAV-based air-to-ground (AG) propagation channels need more detailed descriptions and accurate models. In this paper, we aim to perform cluster-based characterization and modeling for AG channels. To our best knowledge, this is the first study that concentrates on the clustering and tracking of multipath components (MPCs) for time-varying AG channels. Based on measurement data at 6.5 GHz with 500 MHz of bandwidth, we first estimate potential MPCs utilizing the space-alternating generalized expectati","authors_text":"Bo Ai, C\\'esar Briso-Rodr\\'iguez, Claude Oestges, Ke Guan, Zhangdui Zhong, Zhuangzhuang Cui","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"eess.SP","submitted_at":"2021-08-26T16:50:27Z","title":"Cluster-based Characterization and Modeling for UAV Air-to-Ground Time-Varying Channels"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2108.11902","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":"sha256:77d028996d9f0fc701b1676a78a2183bddeb19e03c770ebc9f95fa8f8bb65624","target":"record","created_at":"2026-07-05T03:09:10Z","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":"15ff294f71a544f9b36f57e7cd6b6942b148c328e4243cb9e9fab44b51181b7b","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"eess.SP","submitted_at":"2021-08-26T16:50:27Z","title_canon_sha256":"b8b5ccbdc18f209fb537195ae3361f51a9efd62fb7ead16c12b4c21af94f1adf"},"schema_version":"1.0","source":{"id":"2108.11902","kind":"arxiv","version":1}},"canonical_sha256":"8f550638bf0e1e56ba0865855c7de547c9b7c01f30e8e6a089045f6e710d2580","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"8f550638bf0e1e56ba0865855c7de547c9b7c01f30e8e6a089045f6e710d2580","first_computed_at":"2026-07-05T03:09:10.787791Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-07-05T03:09:10.787791Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"kHCa1xgdsJScZS96wE63wNk+gZCLrcN/FnFz4GjjZa5CsbNHE4K9ogLvs9barZ35XvNUyw6xkOCeGbGdXGYxAw==","signature_status":"signed_v1","signed_at":"2026-07-05T03:09:10.788129Z","signed_message":"canonical_sha256_bytes"},"source_id":"2108.11902","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:77d028996d9f0fc701b1676a78a2183bddeb19e03c770ebc9f95fa8f8bb65624","sha256:7fcb59ac6ff497219c359dcb04144d1a3b4bbd8bc8f0df2c909c3d9cc76725b3"],"state_sha256":"d4056f3fececb9fa5f0f559141dea30d247329b6c99a0d5b4d04f4ddf90daa62"}