再补充VCLT，

你可以看到，when death signal comes, if you start short, then you will have 64% chance to win. It is typical death then price move downward case. 
After optimization, when select signal comes , you will have 90% to win if you start short. The averge return is also better. So if you read my previous post, then you can tell, when QQQ dealth signal come, long QQQ, if VCLT has death signal, then short it.  I call it stock personality.