Hiroyuki Chishiro

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This paper proposes semi-fixed-priority scheduling to achieve both low-jitter and high schedulability. Semi-fixed-priority scheduling is for the extended imprecise computation model, which has a wind-up part as a second mandatory part and schedules the part of each extended imprecise task with fixed-priority. This paper also proposes a novel(More)
Modular component-based robot systems require not only an infrastructure for component management, but also scalability as well as real-time properties. Robot Technology (RT)-Middleware is a software platform for such component-based robot systems. Each component in the RT-Middleware, so-called ``RT-Component'' supporting particular robot functions, is(More)
Current real-time systems such as robots have multiprocessors and the number of processors tends to be increased. In order to achieve these real-time systems, global real-time scheduling has been required. Many real-time scheduling algorithms are usually based on Liu and Layland's model. Compared to Liu and Layland's model, the imprecise computation model(More)
This paper presents RT-Est, which is a real-time operating system for semi-fixed-priority scheduling algorithms. RT-Est implements the following mechanisms: (i) the hybrid O(1) scheduler, which is an extension of the O(1) scheduler in Linux kernel 2.6, to achieve semi-fixed-priority scheduling with low overhead, (ii) the high resolution timer, which(More)
An imprecise computation model has the advantage of supporting overloaded conditions in dynamic real-time environments, compared to Liu and Layland's model. However, the imprecise computation model is not practical because the termination of each optional part cannot guarantee the schedulability. In order to guarantee the schedulability of the termination(More)
This paper proposes Reduction to Uniprocessor Transformation (RUNT), which is an optimal multiprocessor real-time scheduling algorithm based on RUN with Real-Time Static Voltage and Frequency Scaling, called S-RUNT, and Real-Time Dynamic Voltage and Frequency Scaling, called D-RUNT. D-RUNT uses Enhanced Cycle-Conserving Earliest Deadline First to make use(More)
The continuing economic boom has seen that many people become interested in automated trading systems with timing constraints and quality of service, called real-time trading systems. In order to realize such real-time trading systems, multi-/many-core processors are required. However, real-time trading systems are somewhat complex, and real-time operating(More)
We introduce the research overview of the practical imprecise computation model to achieve imprecise real-time applications. The practical imprecise computation model has multiple mandatory parts as real-time parts and multiple optional parts as non-real-time parts. We explain a new concept of real-time scheduling in the practical imprecise computation(More)
The robotics field provides with many typical applications of Cyber-Physical Systems (CPS). Robots are expected to be deployed in a wide variety of applications including life supporting work or disaster response and therefore they need to follow strict safety and dependability constraints. In order to create robots with high utility, safety and(More)
Existing multiprocessor real-time scheduling algorithms follow partitioning/global scheduling approaches or some hybrid approaches of the two. Under partitioning, all tasks are assigned to specific processors. Under global scheduling, tasks may migrate among processors. Global scheduling has the advantage of better schedulability compared to partitioning.(More)