A Multi-Source Data Fusion and PSO-Transformer Decision Support System for Gold Price Volatility Forecasting and Risk Warning

Gold volatility responds to shocks and sentiment, yet the two are rarely fused, and forecasts seldom become actionable. We link a multi-source fusion subsystem to a risk-warning layer through a Transformer whose three pre-registered hyperparameters are searched by particle swarm optimization (PSO-Transformer). It fuses video sentiment, headline scoring and market factors screened to 20 of 21 candidates; the decision side maps the predicted realized variance RVt/Mt (bp2, non-annualized) into three traffic-light tiers of a calibrated predictive distribution. On 5-min spot gold data (January–June 2025, 126 trading days), the PSO-Transformer attains a one-step MAE of 8.038, a 36.5% average improvement over seven baselines under protocol P1, where selection and evaluation share one window; under the leak-free protocol P2, the same pipeline attains 10.16 against 8.82 for the GRU, so the first place reflects the P1 design, not an independent out-of-sample comparison. Diebold–Mariano gains over GARCH, SVM and XGBoost survive a Holm correction. Walk-forward backtesting over 59 origins with persistence-anchored alerts yields 67.8% tier accuracy, 78.8% high-risk precision and 92.9% recall, with the neural engine fed into the same rule attaining 45.5% against 61.4%. One instrument, six months: a documented architecture, not a demonstrated transfer.