## 5 Convergence of ML and Blockchain in IoV
### Prospects of ML and BC Convergence for IoV System
#### 5.1.6 Secure Energy-Trading System
\begin{table}
\begin{tabular}{c c c c c} \hline
**Ref.** & **Application** & **BC Type/Consensus Mechanism** & **ML Adopted** & **Key Findings** \\ \hline [PERSON] et al. [158] & Efficient data sharing & \begin{tabular}{c} Permissioned blockchain \\ (Directed Acyclic Graph (DAG)) \\ \end{tabular} & Asynchronous FL & \begin{tabular}{c} The proposed scheme achieved improved learning \\ accuracy as well as faster convergence. \\ \end{tabular} \\ \hline [PERSON] et al. [153] & Efficient traffic data sharing & BFT-DFOCS & Opportunistic FL & \\ \hline [PERSON] et al. [146] & Efficient traffic data management & DPOF & DRL & The proposed approach achieved minimizing the system latency and improved the data safety and user utility. \\ \hline [PERSON] et al. [147] & Efficient traffic prediction & Permissioned blockchain & FL & The proposed system enabled a decentralized model training. \\ \hline [PERSON] et al. [148] & \begin{tabular}{c} Effective incentive-enabled traffic \\ information sharing \\ \end{tabular} & PoS & ANN-based ANFIS & \begin{tabular}{c} The proposed system enhanced the security and privacy of the system and enabled improved \\ user participation. \\ \end{tabular} \\ \hline [PERSON] et al. [141] & \begin{tabular}{c} Efficient autonomous \\ lane-changing behavior \\ \end{tabular} & BFT-DFOCS & DRL & The proposed model achieved over 96.5% ratio of successful lane changes and was robust in defending against malicious nodes. \\ \hline [PERSON] et al. [159] & \begin{tabular}{c} Effective collective learning for \\ autonomous driving \\ \end{tabular} & BFT-DFOCS & DRL & The proposed approach’s average positioning performance increased by 83.78% and achieved the smallest positional error for the same number of cooperators. \\ \hline [PERSON] and [PERSON] [160] & \begin{tabular}{c} Effective learning for \\ autonomous cars \\ \end{tabular} & Public blockchain & RL & \begin{tabular}{c} The proposed method demonstrated better \\ performance in terms of service time and data traffic than the existing heuristic search methods. \\ \end{tabular} \\ \hline [PERSON] et al. [161] & Efficient adaptive sharding & PBFT & DRL & The proposed approach lowered the communication overhead and was adaptive. \\ \hline [PERSON] et al. [142] & \begin{tabular}{c} Efficient information sharing for \\ accurate cooperative positioning \\ \end{tabular} & DFOCS & DL & \begin{tabular}{c} The proposed approach improved the positioning \\ accuracy of vehicles with increase in speed of vehicle. \\ \end{tabular} \\ \hline [PERSON] et al. [162] & Secure content caching & & & The proposed scheme achieved privacy protection \\  & & & & and secure content transaction. \\ \hline [PERSON] et al. [163] & Secure predictive caching system & \
\begin{tabular}{c} Bi-LSTM, deep \\ Q-learning (DQN) \\ \end{tabular} &
\begin{tabular}{c} The proposed scheme attained higher cache hit \\ ratio than other compared approaches and also \\ ensured data privacy protection. \\ \end{tabular} \\ \hline \end{tabular}
\end{table} 
Table 7: _Cont._ \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Ref.** & **Application** & **BC TypeConsensus Mechanism** & **ML Adopted** & **Key Findings** \\ \hline [PERSON] et al. (2016) & Secure EV charging system & Consortium Blockchain & k-NN & The proposed approach attained great reduction in computational delay and resolved inherent storage issues. \\ \hline [PERSON] et al. (2016) & Effective content caching system & PoU & DRL & The proposed approach achieved the minimum cumulative average reward as compared to two known methods. \\ \hline [PERSON] et al. (2014) & Intrusion detection system for energy grid & FL & The proposed system achieved improvement in security and privacy in data transmission. \\ \hline [PERSON] et al. (2015) & Secure electricity network & PBFT & RNN & The proposed approach achieved an accuracy of 96.82\%. \\ \hline \hline \end{tabular}
\end{table} 
Table 7: _Cont._