It has accelerated its security as a way of improvement and in the time of transaction. The one who has changed the blockchain structure of Bitcoin in a tree, its 2013 letter of Sompolinsky and Zohar has introduced blockade structure on the GOHOST protocol.
This is an alternative network structure of BlockDag, which blocks its protocol, which is called Phantom. This PhD Candidate Jonathan Somapolinsky and Dr. Both Aviv Zohar and Hebrew University of Jerusalem have released a letter on a new scalable this week.
Source https://cointelegraph.com/news/researchers-propose-new-version-of-scalable-blockchain-alternative