The shepherding problem is to collect several sheep and guide them to some destinations and is possible to be applied to some situations such as evacuation guidance at facilities in which a few people need to guide many people to evacuation doors. The present paper aims to clarify methods in which two sheepdogs guide a herd of sheep effectively through the shepherding problem. Especially, we focus on the effectiveness of cooperative behavior of sheepdogs. To show them, we introduce three controlling models depending on the degree of interference in sheepdogs' behaviors. The effectiveness of sheepdog behavior is evaluated by the success rate, number of steps, moving distance of sheepdogs, and dispersion of sheep. It is shown that cooperative and uncooperative behavior have respective advantages in those results.

Roundabouts are circular intersections which can function without traffic signals. We conduct simulations using a cellular automaton model with vehicles and pedestrians to investigate congestion on a single-lane roundabout. When there are pedestrian crosswalks at the roundabout, on which pedestrians have right of way over vehicles, pedestrians crossing with high frequency may interrupt traffic flow. We consider both conservative and rational road crossing behaviors and their impacts on traffic flow. Furthermore, we investigate two types of traffic lights at roundabouts in terms of how they differentially affect traffic flow. Our results could be used to design crossings without traffic congestion.