Credit: World Scientific Human beings are living inside an ocean of signals. These signals enable human beings to demonstrate intelligence. Similarly, machines are also surrounded by signals. Artificial intelligence (AI) or machine intelligence has become a hot topic for many decades due to the high expectation of the public on the emergence of smart machines and smart products. However, the AI research community is still struggling to determine the foci of machine intelligence. For instance, the low-level focus of AI is to advocate computer-aided human intelligence. We believe that the more challenging focus should aim at creating machines that can achieve human-like self-intelligence by themselves.