Investors looking to boost their exposure to artificial intelligence should target China, according to Matthews Asia portfolio manager Andrew Mattock. He said investors will need a more deliberate approach because broad emerging market strategies won't be that effective. "Investors need to be aware when they buy an emerging market fund or when they buy a plain vanilla MSCI product… they're not getting a lot of it," Mattock told CNBC's "ETF Edge" this week. "The big piece that you are missing… is the Chinese piece." He noted that companies from South Korea and Taiwan comprise almost half of the iShares MSCI…