1. Dynamically Reconfiguring Hierarchies Walter Hsueh CS446 Software Engineering with

2. DRH Motivation What is a DRH? –A Dynamically Reconfiguring Hierarchy allows for a smooth and uninterrupted transfer of control and resources from one agent to another. Transfer of control via a change in the topology of the information transport mechanism. A DRH usually operates in a mixed hardware and software environment.

3. DRH Motivation, Part II Common Characteristics of DRH Systems: –versatility –flexibility –fault tolerance and safety –lower maintenance and turn around time. Applications: –Military –Robotic / AI –Fault-Tolerance –Computer Hardware and Software –Networks / Internet

4. Robotic Applications of DRH AGV: Autonomous Guidance Vehicle –AGV attaches itself to different guidance controllers as it passes through different control domains

5. AI Applications of DRH DS1 - Deep Space 1, launched October 24, 1998 Remote Agent has 3 modules: –Planner / Scheduler –Executive –MIR: Mode Identification and Reconfiguration MIR responsibilities: –monitors spacecraft systems –assesses impact of failures on mission goals –determines how to proceed in light of failures.

6. DRH in Computer Systems Shared Memory / Cache architectures Plug & Play, Hot-Swap RAID, Fault Tolerance

7. At any given time, some part of the Internet is broken. The topology of (inter)networks are dynamically reconfigured using: –route computation algorithms –broadcast / TTL messages Networks / Internet Jini - a Sun technology for automatic resource discovery and configuration on a Java-centric network

8. Rapide Rapide is an event-modeling system. Rapide is ideal for representing DRH simulations. Causal events encapsulate the protocol used to reconfigure –control hierarchies –information bus topologies