One day I found a process named
Desktop Video Firmware Updater which has an ugly icon on the system activity app on Mac and then I figured out it was from Blackmagic Design software which I installed at the past time. But, I don’t use it now.
I tried to kill the process, but, I couldn’t do it. So I found the location of the execution file at the link below,
/Library/Application Support/Blackmagic Design/Blackmagic DeckLink/Desktop Video Firmware Updater.app/Contents/MacOS/Desktop Video Firmware Updater
After removing it I finally can’t see it on the activity window. If someone has used Blackmagic Design software on Mac, please refer this post to clean up your processes on Mac.