A study of the IEEE 1394 cluster and its application in parallel transportation simulation systems

Abstract

The design of modern transportation systems leads to many challenges and it makes great impact on societies. The foremost issues concern safety, delays due to congestion, and vulnerability due to natural and man-made disasters. Computer simulations of transportation system provide a mean to study the system performance or to evaluate different strategies in order to determine the most effective solution for a problem. While large-scale computer simulations may require a long time to complete, decisions often must be made promptly and therefore, parallel and distributed simulation methods are often used to reduce the execution-time of such large-scale simulations. High-end supercomputers had been dominating this field in the past decades, but the high prices of high-end supercomputers made the common applications impossible. There are remarkable progresses in the parallel and distributed simulation field recently and network of workstations or clusters which composed of many workstations interconnected through a network become a popular method to speedup large-scale simulation systems. Cost-effectiveness is the major factor that drives the use of computer clusters in simulation systems. High-end computer clusters are still not popular due to the very costly interconnection medium. In this thesis, a computer cluster is proposed, which employs a new interconnection device - the IEEE 1394, or Firewire, as the interconnection media. The IEEE 1394 is relatively low in price, while good in performance comparing to other interconnection medium. Such cluster is employed to implement two typical microscopic transportation simulation systems, the performance improvement of the two systems are observed, and therefore, these systems can accommodate large-scale simulations in shorter time. This allows the simulation systems to be applied in different aspects including decision making or personnel training of the different transportation systems. The Firewire system is originally designed for interconnected digital audio/video equipments to a computer and in order to utilize the device as a general purpose networking media, a custom-designed communication protocol is devised. The protocol is tailored for implementing parallel application over the IEEE 1394 device. The new protocol reduces the communication overhead and an improvement of around 25% is shown when comparing to the traditional TCP/IP protocol over the IEEE 1394 device. In order to fully utilize the transmission capacity of the two operation modes of the IEEE 1394 device, and to support basic QoS (Quality of Service) feature, a fuzzy control mechanism is applied to the communication protocol. With this fuzzy control mechanism, the protocol can maximize the overall performance according to the data transmission format of different applications. The fuzzy controlled communication protocol shows a speedup factor of up to 20% when comparing to the ordinary mechanism. The performance of the IEEE 1394 cluster based on our new protocol is also compared to the clusters using other interconnection media such as the Ethernet to illustrate the differences in terms of cost-effectiveness. Case studies of two typical transportation simulation applications, namely the Railway Operation Simulation System and the Urban Traffic Simulation System, which run on the IEEE 1394 cluster were carried out, the results substantiated that these application benefit significantly from such a cluster. The communication protocol is suitable for applications with different data transmission characteristics and this gives a good prospect in utilizing parallel computing in transportation simulations. Case studies in the thesis are carried out on a cluster, which consists of only four workstations. A statistical model is developed to estimate the performance of such cluster in a larger scale. The model shows that with a cluster that consists of 64 workstations, the performance is still acceptable.