The cellular automation traffic flow model of roundabout with inner-roundabout-lane, injection-roundabout-lane and extraction-roundabout-lane is used to study the traffic flow of single loop roundabout under open boundary conditions. Through computer simulation, the relationships between the entrance probability, exit probability, vehicle braking probability and system flow, the average speed of each lane and system in the open boundary conditions are studied.Besides, the space-time diagram of vehicles on the injection-roundabout-lane with different entrance exit probabilities and the system phase diagram are established. In the system phase diagram, the critical entry probability and exit probability values of each part of the phase diagram under different braking probability are given. The results show that the system traffic flow can be divided into three phases: the phase in which the system flow changes with the entrance probability, the phase in which the system flow changes with the exit probability, and the phase in which the system flow has nothing to do with the entrance probability and exit probability. This will provide some guidance for road management.

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In the actual production applications and scientific research experiments, the process of the development, test, operation and application of a system will produce a large number of original data. And most of them are pulse type data. Normally, users can achieve to access the short pulse data in one time expediently. While for long pulse data, the requirement sometimes just need to read and analyze a certain segment of the long pulse data, and it also takes a lot of time to access all the data at once. So a data segmented processing software is designed and implemented in this paper for long pulse data. It provides convenience for users to view any segment of long pulse data in real time by the data decompressing and segmented processing process. The software is development by C++ programming language with a friendly interface. The key technologies are based on the open source lossless LZO compress and decompress algorithm, as well as a custom data segmentation algorithm. Now, the software has been tested and the results show that it can work stably and reliably.