Complex sentence: Quasi-opportunistic supercomputing is a computational paradigm in which a large number of geographically disperse computers, often under different ownerships, are utilized to achieve reliable and fault-tolerant high performance with more control than opportunistic grids in which computational resources are used whenever they may become available.
Split into simpler sentences: Quasi-opportunistic supercomputing is a computational paradigm for supercomputing on a large number of geographically disperse computers. The quasi-opportunistic approach coordinates computers which are often under different ownerships to achieve reliable and fault-tolerant high performance with more control than opportunistic grids in which computational resources are used whenever they may become available.