{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2012:U2L5AH7F3SV45APF7X3IW7CPSR","short_pith_number":"pith:U2L5AH7F","canonical_record":{"source":{"id":"1211.4932","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.IM","submitted_at":"2012-11-21T04:26:57Z","cross_cats_sorted":[],"title_canon_sha256":"2830d37bc9cc10a43d152489b8438ceecd7beb054e4aefb6be19b855d86e7144","abstract_canon_sha256":"0798fbf1ce57c7f5965139c72c5c019dc0fb3c532e8941779df768497dbdf0ce"},"schema_version":"1.0"},"canonical_sha256":"a697d01fe5dcabce81e5fdf68b7c4f946ad3d4258a36b9b9428f05f107c1e306","source":{"kind":"arxiv","id":"1211.4932","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1211.4932","created_at":"2026-05-18T01:53:02Z"},{"alias_kind":"arxiv_version","alias_value":"1211.4932v1","created_at":"2026-05-18T01:53:02Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1211.4932","created_at":"2026-05-18T01:53:02Z"},{"alias_kind":"pith_short_12","alias_value":"U2L5AH7F3SV4","created_at":"2026-05-18T12:27:23Z"},{"alias_kind":"pith_short_16","alias_value":"U2L5AH7F3SV45APF","created_at":"2026-05-18T12:27:23Z"},{"alias_kind":"pith_short_8","alias_value":"U2L5AH7F","created_at":"2026-05-18T12:27:23Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2012:U2L5AH7F3SV45APF7X3IW7CPSR","target":"record","payload":{"canonical_record":{"source":{"id":"1211.4932","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.IM","submitted_at":"2012-11-21T04:26:57Z","cross_cats_sorted":[],"title_canon_sha256":"2830d37bc9cc10a43d152489b8438ceecd7beb054e4aefb6be19b855d86e7144","abstract_canon_sha256":"0798fbf1ce57c7f5965139c72c5c019dc0fb3c532e8941779df768497dbdf0ce"},"schema_version":"1.0"},"canonical_sha256":"a697d01fe5dcabce81e5fdf68b7c4f946ad3d4258a36b9b9428f05f107c1e306","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T01:53:02.128902Z","signature_b64":"8CfcTDcY1j9CWClglDsoJKWaavs0BPq/DcP6E6bvSwmFoKE0HLURQhLMmSvcE8xuBtI0Vdm54sFDZeq5BAMaCQ==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"a697d01fe5dcabce81e5fdf68b7c4f946ad3d4258a36b9b9428f05f107c1e306","last_reissued_at":"2026-05-18T01:53:02.128424Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T01:53:02.128424Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1211.4932","source_version":1,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T01:53:02Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"2xDmGxj6MAHuN3hx077kK2yO4fCkDsPxiybUOae6h/KNQZjiIdipa1DIXcnaFd6P3ty8su1hEaStu4l1eFZeBg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-04T06:19:40.007103Z"},"content_sha256":"195aa699666368d28ee916aa9a3968adab45acb894d9624320d6a8fe1a55ed9b","schema_version":"1.0","event_id":"sha256:195aa699666368d28ee916aa9a3968adab45acb894d9624320d6a8fe1a55ed9b"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2012:U2L5AH7F3SV45APF7X3IW7CPSR","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Square Kilometre Array station configuration using two-stage beamforming","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.IM","authors_text":"Aziz Jiwani, Jan Geralt bij de Vaate, Nima Razavi-Ghods, Peter J Hall, Shantanu Padhi, Tim Colegate","submitted_at":"2012-11-21T04:26:57Z","abstract_excerpt":"The lowest frequency band (70 - 450 MHz) of the Square Kilometre Array will consist of sparse aperture arrays grouped into geographically-localised patches, or stations. Signals from thousands of antennas in each station will be beamformed to produce station beams which form the inputs for the central correlator. Two-stage beamforming within stations can reduce SKA-low signal processing load and costs, but has not been previously explored for the irregular station layouts now favoured in radio astronomy arrays. This paper illustrates the effects of two-stage beamforming on sidelobes and effect"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1211.4932","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"},"verdict_id":null},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T01:53:02Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"qmY0+5fHHQa9UkMMeaL8+QDkM52yi3IkZtcNunCHIJE8tnCykzpMjU7qUAkyib+bh04Ux5EioAPgES5RlWxhAw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-04T06:19:40.009350Z"},"content_sha256":"4e8dbd6ea5f0572d16d8b478a975da45382768b468ec06d3f73d66cec0d15659","schema_version":"1.0","event_id":"sha256:4e8dbd6ea5f0572d16d8b478a975da45382768b468ec06d3f73d66cec0d15659"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/U2L5AH7F3SV45APF7X3IW7CPSR/bundle.json","state_url":"https://pith.science/pith/U2L5AH7F3SV45APF7X3IW7CPSR/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/U2L5AH7F3SV45APF7X3IW7CPSR/bundle.json","status":"primary"}],"public_keys":[{"key_id":"pith-v1-2026-05","algorithm":"ed25519","format":"raw","public_key_b64":"stVStoiQhXFxp4s2pdzPNoqVNBMojDU/fJ2db5S3CbM=","public_key_hex":"b2d552b68890857171a78b36a5dccf368a953413288c353f7c9d9d6f94b709b3","fingerprint_sha256_b32_first128bits":"RVFV5Z2OI2J3ZUO7ERDEBCYNKS","fingerprint_sha256_hex":"8d4b5ee74e4693bcd1df2446408b0d54","rotates_at":null,"url":"https://pith.science/pith-signing-key.json","notes":"Pith uses this Ed25519 key to sign canonical record SHA-256 digests. Verify with: ed25519_verify(public_key, message=canonical_sha256_bytes, signature=base64decode(signature_b64))."}],"merge_version":"pith-open-graph-merge-v1","built_at":"2026-06-04T06:19:40Z","links":{"resolver":"https://pith.science/pith/U2L5AH7F3SV45APF7X3IW7CPSR","bundle":"https://pith.science/pith/U2L5AH7F3SV45APF7X3IW7CPSR/bundle.json","state":"https://pith.science/pith/U2L5AH7F3SV45APF7X3IW7CPSR/state.json","well_known_bundle":"https://pith.science/.well-known/pith/U2L5AH7F3SV45APF7X3IW7CPSR/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2012:U2L5AH7F3SV45APF7X3IW7CPSR","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":"0798fbf1ce57c7f5965139c72c5c019dc0fb3c532e8941779df768497dbdf0ce","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.IM","submitted_at":"2012-11-21T04:26:57Z","title_canon_sha256":"2830d37bc9cc10a43d152489b8438ceecd7beb054e4aefb6be19b855d86e7144"},"schema_version":"1.0","source":{"id":"1211.4932","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1211.4932","created_at":"2026-05-18T01:53:02Z"},{"alias_kind":"arxiv_version","alias_value":"1211.4932v1","created_at":"2026-05-18T01:53:02Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1211.4932","created_at":"2026-05-18T01:53:02Z"},{"alias_kind":"pith_short_12","alias_value":"U2L5AH7F3SV4","created_at":"2026-05-18T12:27:23Z"},{"alias_kind":"pith_short_16","alias_value":"U2L5AH7F3SV45APF","created_at":"2026-05-18T12:27:23Z"},{"alias_kind":"pith_short_8","alias_value":"U2L5AH7F","created_at":"2026-05-18T12:27:23Z"}],"graph_snapshots":[{"event_id":"sha256:4e8dbd6ea5f0572d16d8b478a975da45382768b468ec06d3f73d66cec0d15659","target":"graph","created_at":"2026-05-18T01:53:02Z","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":"The lowest frequency band (70 - 450 MHz) of the Square Kilometre Array will consist of sparse aperture arrays grouped into geographically-localised patches, or stations. Signals from thousands of antennas in each station will be beamformed to produce station beams which form the inputs for the central correlator. Two-stage beamforming within stations can reduce SKA-low signal processing load and costs, but has not been previously explored for the irregular station layouts now favoured in radio astronomy arrays. This paper illustrates the effects of two-stage beamforming on sidelobes and effect","authors_text":"Aziz Jiwani, Jan Geralt bij de Vaate, Nima Razavi-Ghods, Peter J Hall, Shantanu Padhi, Tim Colegate","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.IM","submitted_at":"2012-11-21T04:26:57Z","title":"Square Kilometre Array station configuration using two-stage beamforming"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1211.4932","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":"sha256:195aa699666368d28ee916aa9a3968adab45acb894d9624320d6a8fe1a55ed9b","target":"record","created_at":"2026-05-18T01:53:02Z","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":"0798fbf1ce57c7f5965139c72c5c019dc0fb3c532e8941779df768497dbdf0ce","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.IM","submitted_at":"2012-11-21T04:26:57Z","title_canon_sha256":"2830d37bc9cc10a43d152489b8438ceecd7beb054e4aefb6be19b855d86e7144"},"schema_version":"1.0","source":{"id":"1211.4932","kind":"arxiv","version":1}},"canonical_sha256":"a697d01fe5dcabce81e5fdf68b7c4f946ad3d4258a36b9b9428f05f107c1e306","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"a697d01fe5dcabce81e5fdf68b7c4f946ad3d4258a36b9b9428f05f107c1e306","first_computed_at":"2026-05-18T01:53:02.128424Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T01:53:02.128424Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"8CfcTDcY1j9CWClglDsoJKWaavs0BPq/DcP6E6bvSwmFoKE0HLURQhLMmSvcE8xuBtI0Vdm54sFDZeq5BAMaCQ==","signature_status":"signed_v1","signed_at":"2026-05-18T01:53:02.128902Z","signed_message":"canonical_sha256_bytes"},"source_id":"1211.4932","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:195aa699666368d28ee916aa9a3968adab45acb894d9624320d6a8fe1a55ed9b","sha256:4e8dbd6ea5f0572d16d8b478a975da45382768b468ec06d3f73d66cec0d15659"],"state_sha256":"0368bbf2c576cec253609aff7f635f517dc617629d9febebf9eca635808ccf98"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"RrqZ2O/GwqY3+r+xffJOQxvYLfs+SxPmEMAVpV23HFF7zFE8yttSFWmkyhEsmda4Sb2i680XcP1QCA4vJwu4Dw==","signed_message":"bundle_sha256_bytes","signed_at":"2026-06-04T06:19:40.011281Z","bundle_sha256":"802ef16fdd5b49b575aa542b8c0eed3093c391807f9e5fd7fa8d99be2e9d95b1"}}