Well, you can't access it as `this` since `this` means something else within the eventProcessActor, but I think this should work:
```scala
private[this] val thisDAGScheduler = this
env.actorSystem.actorOf(Props(new Actor {  // the Supervisor
  ...
  eventProcessActor = context.actorOf(Props(new Actor {
    ...
    override def preStart() {
      taskScheduler.setDAGScheduler(thisDAGScheduler)
    }
...
```