A scheduling algorithm for ASOS and its application to traffic control

Application specific operating systems (ASOS) are developing quickly as a new trend of the embedded operating systems and can be applied to many fields including intelligent transportation systems. According to the characteristics of real-time tasks and the demand of ASOS, a novel approach based on RM (rate-monotonic) algorithm, named NPT (non-preemptive threshold) algorithm, is investigated. This algorithm can perfectly schedule preemptive and non-preemptive tasks in uniprocessor, whilst some excellence of RM can be also gained. In this paper, properties of NPT are presented properly. In addition, the sporadic server algorithm (SS) can well schedule sporadic tasks. It is also an extension of rate monotonic algorithm, thus some advantages of RM are retained. Intersection signal control is an important part of intelligent transportation systems. It is a concrete application of ASOS. We apply NPT and SS to intersection signal controller for non-preemptive and sporadic tasks respectively and achieve content results.