Did you read the information on the sites you linked to in your question?? The answer is right there....
No, they are not the same... Accelerator is a data-parallel computation library that targets GPU (it's designed for parallel processing of large data arrays). CCR/DSS is a general purpose managed distributed coordination "platform" (concurrency is a side
effect; the art is in the coordination primitives and port-based programming abstractions).
Accelerator project seems to be too outdated. Charles, fresh interview would be greatly appreciated.