Implementing singleserver with NSA-DEVS

• Changes to the PRDEVS description:
  • start with default parameters for delays
  • additional parameter τ = ε for all components
  • transition time t_D = ε of the state “queuing free”
• Simulation:
  • uses "twisted" PowerRPDEVS for debugging mode
    • set ε = 10^-4
    • add explicit delay component at each input
  • result is wrong - entities get lost
  • reason
    • "busy" message comes too late
    • internal transition of "queuing free" comes before
  • model needs finetuning
    • set t_D > 2 ε → correct results as in PDEVS version
• Comparison of singleserver version:
  • main problem: concurrent events in "queuing free"
  • PDEVS works
    • order defined in confluent transition function
    • hidden under the carpet, difficult for non-experts
  • RPDEVS doesn't work
    • λ iterations don't stop
  • NSA-DEVS works
    • problem is seen explicitely
    • fine-tuning is easy