{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2012:BUR5CIUAO2SEWGWDI64OLYGMGG","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":"0e09d48d53cb6096bc096ba654e37213878b0dd3c94d57c559bb876779fb2c9d","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.CV","submitted_at":"2012-08-27T17:21:39Z","title_canon_sha256":"0e8b949b34cc1be7e59b79e814682e7ecd837679acffc2f250036115f89ffc60"},"schema_version":"1.0","source":{"id":"1208.5451","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1208.5451","created_at":"2026-05-18T03:46:59Z"},{"alias_kind":"arxiv_version","alias_value":"1208.5451v1","created_at":"2026-05-18T03:46:59Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1208.5451","created_at":"2026-05-18T03:46:59Z"},{"alias_kind":"pith_short_12","alias_value":"BUR5CIUAO2SE","created_at":"2026-05-18T12:27:01Z"},{"alias_kind":"pith_short_16","alias_value":"BUR5CIUAO2SEWGWD","created_at":"2026-05-18T12:27:01Z"},{"alias_kind":"pith_short_8","alias_value":"BUR5CIUA","created_at":"2026-05-18T12:27:01Z"}],"graph_snapshots":[{"event_id":"sha256:1c49b469dc9532a72a5ab92a35cc494472d20848e901350bafa7e3fbe4d054a4","target":"graph","created_at":"2026-05-18T03:46:59Z","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":"A framework for unsupervised group activity analysis from a single video is here presented. Our working hypothesis is that human actions lie on a union of low-dimensional subspaces, and thus can be efficiently modeled as sparse linear combinations of atoms from a learned dictionary representing the action's primitives. Contrary to prior art, and with the primary goal of spatio-temporal action grouping, in this work only one single video segment is available for both unsupervised learning and analysis without any prior training information. After extracting simple features at a single spatio-te","authors_text":"Alexey Castrodad, Guillermo Sapiro, Mariano Tepper, Zhongwei Tang","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.CV","submitted_at":"2012-08-27T17:21:39Z","title":"Are You Imitating Me? Unsupervised Sparse Modeling for Group Activity Analysis from a Single Video"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1208.5451","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:b20c68c845fd8b430c096db64cfeb54e89fa727bc9d4184fdbbdc642b618029f","target":"record","created_at":"2026-05-18T03:46:59Z","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":"0e09d48d53cb6096bc096ba654e37213878b0dd3c94d57c559bb876779fb2c9d","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.CV","submitted_at":"2012-08-27T17:21:39Z","title_canon_sha256":"0e8b949b34cc1be7e59b79e814682e7ecd837679acffc2f250036115f89ffc60"},"schema_version":"1.0","source":{"id":"1208.5451","kind":"arxiv","version":1}},"canonical_sha256":"0d23d1228076a44b1ac347b8e5e0cc318da4d4d7fa13ba6f9b46796eb752e7c7","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"0d23d1228076a44b1ac347b8e5e0cc318da4d4d7fa13ba6f9b46796eb752e7c7","first_computed_at":"2026-05-18T03:46:59.438682Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T03:46:59.438682Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"hKFvZgExTSxcCbHiP53Nawip6UI/L3luUjkmAxx4d4f/CQKnrlgzMgGWmv+eoCONNQJQ735Ba/nhYP42MTOJAg==","signature_status":"signed_v1","signed_at":"2026-05-18T03:46:59.439244Z","signed_message":"canonical_sha256_bytes"},"source_id":"1208.5451","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:b20c68c845fd8b430c096db64cfeb54e89fa727bc9d4184fdbbdc642b618029f","sha256:1c49b469dc9532a72a5ab92a35cc494472d20848e901350bafa7e3fbe4d054a4"],"state_sha256":"3ecf84571d1a9a1e2abcdc3db6823a915321e9c9e0a6fa9ca4afe39895d6074e"}