
@Article{cmes.2026.081849,
AUTHOR = {Lilia Tightiz, L. Minh Dang, Hyosik Yang},
TITLE = {QFedFormer: A Privacy-Preserving Federated Transformer with Blockchain-Anchored Incentives for Dynamic EV Charging Pricing},
JOURNAL = {Computer Modeling in Engineering \& Sciences},
VOLUME = {},
YEAR = {},
NUMBER = {},
PAGES = {{pages}},
URL = {http://www.techscience.com/CMES/online/detail/27168},
ISSN = {1526-1506},
ABSTRACT = {We present QFedFormer, a federated transformer for dynamic electric vehicle (EV)-charging price prediction that combines quantization-aware training, SHAP-guided explainability, and blockchain-based incentives. The framework trains across distributed charging stations without centralizing user data, and programmable contracts set tariffs from forecasted demand and user-declared flexibility, while token rewards are derived from SHAP-based utility scores and anchored on-chain via Merkle proofs. On a real-world dataset, QFedFormer attains an energy-demand RMSE of <mml:math id="mml-ieqn-1"><mml:mn>1.82</mml:mn><mml:mo>±</mml:mo><mml:mn>0.02</mml:mn></mml:math> kWh and a tariff RMSE of <mml:math id="mml-ieqn-2"><mml:mn>11.83</mml:mn><mml:mo>±</mml:mo><mml:mn>0.10</mml:mn></mml:math> KRW/kWh (MAPE <mml:math id="mml-ieqn-3"><mml:mn>2.7</mml:mn><mml:mo>±</mml:mo><mml:mn>0.2</mml:mn><mml:mi mathvariant="normal">%</mml:mi></mml:math>) in the non-private baseline, outperforming FedAvg and Block-FeDL by <mml:math id="mml-ieqn-4"><mml:mn>14.1</mml:mn><mml:mi mathvariant="normal">%</mml:mi></mml:math> and <mml:math id="mml-ieqn-5"><mml:mn>9.5</mml:mn><mml:mi mathvariant="normal">%</mml:mi></mml:math>, respectively. Under client-level differential privacy (DP) with <mml:math id="mml-ieqn-6"><mml:mo stretchy="false">(</mml:mo><mml:mi>σ</mml:mi><mml:mo>=</mml:mo><mml:mn>1.6</mml:mn><mml:mo>,</mml:mo><mml:mspace width="thinmathspace"/><mml:mi>C</mml:mi><mml:mo>=</mml:mo><mml:mn>1</mml:mn><mml:mo>,</mml:mo><mml:mspace width="thinmathspace"/><mml:mi>p</mml:mi><mml:mo>=</mml:mo><mml:mn>0.1</mml:mn><mml:mo>,</mml:mo><mml:mspace width="thinmathspace"/><mml:msub><mml:mi>δ</mml:mi><mml:mrow><mml:mrow><mml:mi mathvariant="normal">D</mml:mi><mml:mi mathvariant="normal">P</mml:mi></mml:mrow></mml:mrow></mml:msub><mml:mo>=</mml:mo><mml:msup><mml:mn>10</mml:mn><mml:mrow><mml:mo>−</mml:mo><mml:mn>5</mml:mn></mml:mrow></mml:msup><mml:mo stretchy="false">)</mml:mo></mml:math>, QFedFormer achieves <mml:math id="mml-ieqn-7"><mml:mo stretchy="false">(</mml:mo><mml:mi>ε</mml:mi><mml:mo>=</mml:mo><mml:mn>2.0</mml:mn><mml:mo>,</mml:mo><mml:mspace width="thinmathspace"/><mml:msub><mml:mi>δ</mml:mi><mml:mrow><mml:mrow><mml:mi mathvariant="normal">D</mml:mi><mml:mi mathvariant="normal">P</mml:mi></mml:mrow></mml:mrow></mml:msub><mml:mo>=</mml:mo><mml:msup><mml:mn>10</mml:mn><mml:mrow><mml:mo>−</mml:mo><mml:mn>5</mml:mn></mml:mrow></mml:msup><mml:mo stretchy="false">)</mml:mo></mml:math> after 50 rounds under a Rényi accountant, with forecast accuracy degrading modestly to <mml:math id="mml-ieqn-8"><mml:mn>1.95</mml:mn></mml:math> kWh RMSE (<mml:math id="mml-ieqn-9"><mml:mo>∼</mml:mo></mml:math>7.1% relative increase vs. non-private baseline). Blockchain evaluation shows an average audit latency of <mml:math id="mml-ieqn-10"><mml:mn>58</mml:mn></mml:math> ms per audit round, while a permissioned Ethereum-compatible deployment sustains more than <mml:math id="mml-ieqn-11"><mml:mn>500</mml:mn></mml:math> client updates per minute with gas costs of <mml:math id="mml-ieqn-12"><mml:mo>∼</mml:mo></mml:math>$0.039/client per audit round. These results indicate that QFedFormer enables accurate, privacy-preserving, and auditable coordination of EV–grid interactions, offering both regulators and service providers a practical deployment pathway.},
DOI = {10.32604/cmes.2026.081849}
}



