Toshimitsu Ushio

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A supervisor is said to be mutually nonblocking with respect to a pair of specifications if upon completing a task in any of the specifications, it can continue on to complete the task in the other specification, i.e., the two specifications do not block each other. The notion of mutually nonblocking supervisor was introduced in [4, 5]. In this paper we(More)
The reliable decentralized supervisory control of discrete event systems (DESs) with communication delays is investigated in this paper. For a system equipped with n local supervisors, we formalize the notion of k-reliable (1 ≤ k ≤ n) decentralized supervisor under communication delays, in which some local supervisors are allowed to fail and(More)
We present fixed-point based characterization of several classes of co-observable languages that are of interest in the context of decentralized supervisory control of discrete event systems, including C&P∨D&A co-observable languages, C&P co-observable languages, and D&A co-observable languages [30]. We also provide formulae for computing super/sublanguages(More)
In this paper, we study supervisory control of a class of discrete event systems with simultaneous event occurrences, which we call concurrent discrete event systems, under partial observation. The behavior of the system is described by a language over the simultaneous event set. First, we prove that Lm(G )-closure, controllability, observability, and(More)
A power-aware optimal processor cycle allocation scheme with consideration of fair quality of service (QoS) guarantee in real-time systems is formulated. Although power-aware resource management using dynamic voltage and frequency scaling techniques can be used to resolve the trade-off between QoS maximization and energy consumption minimization, it is also(More)
A novel control method for fair resource allocation and maximization of the Quality of Service (QoS) levels of individual tasks is proposed. In the proposed adaptive QoS controller, resource utilization is assigned to each task through an online search for the fair QoS level based on the errors between the current QoS levels and their average. The proposed(More)