{
  "concept": "4F.1",
  "title": "Height-aware centerline obstruction pre-change baseline",
  "captured_at": "2026-09-17",
  "source": "real backend immediately before Concept 4F.1 implementation",
  "command": "ATOM_REAL_E2E=1 npm run test:e2e -- e2e/real-backend.spec.js --project=desktop-1440",
  "acceptance": {
    "backend_startup": "passed",
    "dataset_footprints": 161784,
    "dataset_towers": 451,
    "real_backend_tests_passed": 2,
    "real_backend_tests_failed": 0,
    "duration_seconds": 8.1
  },
  "scenario": {
    "technology": "5g",
    "frequency_ghz": 28,
    "tx_power_dbm": 30,
    "antenna_height_m": 25,
    "receiver_height_m": 1.5,
    "radius_m": 400,
    "beam_width_deg": 120,
    "rays": 72,
    "tower_ids": [
      "LTE-35084",
      "LTE-35104",
      "LTE-35877",
      "LTE-313100",
      "LTE-313110",
      "LTE-322828"
    ],
    "azimuths_deg": [0, 60, 120, 180, 240, 300]
  },
  "classifier_before": {
    "id": "footprint-2d-v1",
    "rule": "outdoor-to-outdoor paths with one or more footprint boundary events are NLOS",
    "height_evidence": "not exposed",
    "terrain_status": "not exposed"
  },
  "urban_short_range": {
    "baseline": {
      "network_score": 13509330.8,
      "composite_score": 0.391373,
      "unique_demand_buildings": 12,
      "unique_residential_buildings": 82,
      "propagation_reach_score": 18330.7658,
      "overlap_buildings": 10
    },
    "optimized": {
      "azimuths_deg": [150, 300, 110, 300, 290, 100],
      "network_score": 32568641.7,
      "composite_score": 0.489148,
      "unique_demand_buildings": 29,
      "unique_residential_buildings": 137,
      "propagation_reach_score": 22141.6608,
      "overlap_buildings": 0,
      "pareto_frontier_size": 23
    }
  },
  "reference": "concept-4d-canonical-comparison.json",
  "notes": [
    "This artifact preserves the measured urban_short_range 2D-footprint baseline before height-aware classification.",
    "No 4F.1 height provenance, terrain-status, or old-to-new transition fields existed in this pre-change response.",
    "The 4F.1 implementation keeps the urban path-loss equations and optimizer objective definitions unchanged; any metric movement is measured as shared RF classification impact."
  ]
}