Verteilter adaptiver Verkehrsmonitor

This project deals with the design of a distributed fault tolerant computer architecture for jointly operating IVMS Intelligent Variable Message Sign) stations. With this new IVMS approach, the task of traffic control is performed in a distributed way. Conventional traffic control systems have, in contrast, one central computer with distributed data acquisition systems attached to it. IVMS stations communicate via point-to-point communication links. They use artificial intelligence methods to smooth the traffic flow along highways. One IVMS station controls an area of 5-10 km. The aim of this dissertation is to design a highly available low-cost computer architecture. Triple modular redundancy, duplex and simplex concepts for application in one station are evaluated using Markov models. The comparison has shown that the simplex approach is the most interesting one, but it does not support static redundancy. Therefore, the fault tolerant measures concentrate on transient failures, which occur up to 10 times more often than the permanent ones. The recovery algorithm of the Manetho Project is adapted in order to overcome transient failures. In particular the problems of the missing stable storage server and network partitioning are solved with the presented computer architecture. In addition to this Membership and Reliable Broadcast protocols are developed and time estimations are given. In order to demonstrate the correct behavior o...(this text has been cut automatically)