Forecasting returns for the Artificial Intelligence and Robotics Index is of great significance for financial market stability, and the development of the artificial intelligence industry. To provide investors with a more reliable reference in terms of artificial intelligence index investment,...

It is well established in the literature that customer retention is at least as important as customer acquisition, especially in the freemium-based virtual economy, in which individuals are connected by multi-relational social networks, such as the “friendships” and “guilds” (virtual...