CPS (Cyber Physical Systems) tightly couple their cyber factor and physical factor in distributed computing or Grids environments to provide real-time services such as avionics, transportation, manufacturing processes...
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CPS (Cyber Physical Systems) tightly couple their cyber factor and physical factor in distributed computing or Grids environments to provide real-time services such as avionics, transportation, manufacturing processes, energy, healthcare, etc. We need to consider not only the cyber space (CPU, network, storage systems, etc.) and the physical space (location, migration, etc.) but also the socio space and mental space for the precise analysis and useful services. In this paper, real-time scheduling algorithms, namely ELST (Effective Least Slack time First) and H-ELST (Heuristic-Effective Least Slack time First), are presented for CPS, where servicing node needs to move to serviced node for real-time services. We measure the real-time performance in terms of deadline meet ratio by mathematical analysis and simulations. The results show that our algorithms reduce a deadline miss ratio approximately up to 50% and 20% compared to the conventional real-time scheduling algorithm, FIFO (First In First Out) and LST (Least Slack time First), respectively. (C) 2013 Elsevier B.V. All rights reserved.
A cyber-physical system (CPS) is a system of collaborating computational elements controlling physical entities. Today, a precursor generation of cyber-physical systems can be found in areas as diverse as aerospace, a...
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A cyber-physical system(CPS) is a system of collaborating computational elements controlling physical ***,a precursor generation of cyber-physical systems can be found in areas as diverse as aerospace,automotive,chemi...
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ISBN:
(纸本)9781467397155
A cyber-physical system(CPS) is a system of collaborating computational elements controlling physical ***,a precursor generation of cyber-physical systems can be found in areas as diverse as aerospace,automotive,chemical processes,civil infrastructure,energy,healthcare,manufacturing and transportation,entertainment,and consumer *** generation is often referred to as embedded *** embedded systems the emphasis tends to be more on the computational elements,and less on an intense link between the computational and physical *** will lead to the problem of low resource utilization and the low real-time system *** at the above problems,based on the CPS of the mobile node for realtime service,this paper proposes the effective shortest time priority algorithm and the adaptive shortest time priority *** results show that,compared with the traditional FIFO(advanced first in first out) and LSF(least slack first) algorithm,the algorithm proposed in this paper effectively reduce the deadline miss ratio,as a result,the real-time performance of the CPS are effectively improved.
Recently, multiprocessor platform is generally used in embedded realtime systems. The optimal realtimeschedulingalgorithms for multiprocessor are demanded. Several algorithms based on RM are proposed. In this stud...
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Recently, multiprocessor platform is generally used in embedded realtime systems. The optimal realtimeschedulingalgorithms for multiprocessor are demanded. Several algorithms based on RM are proposed. In this study, we propose RMZLPD based on RMZL applied zero-laxity rule to RM. RMZLPD can realize high parallelism. Through simulation, RMZLPD has shown the high schedule success ratio. The schedulability of proposed algorithm also is shown by response time analysis.
In many real-time systems, there are not only periodic real-time tasks, but also aperiodic real-time tasks arising from arbitrary critical events. In this paper, we propose an algorithm (SATSS, Schedule Aperiodic Task...
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ISBN:
(纸本)9780769536347
In many real-time systems, there are not only periodic real-time tasks, but also aperiodic real-time tasks arising from arbitrary critical events. In this paper, we propose an algorithm (SATSS, Schedule Aperiodic Tasks on a Static Schedule) scheduling both periodic real-time tasks and aperiodic real-time tasks. This algorithm first produces a schedule which consists of only periodic tasks before the system is started and schedules aperiodic tasks on the static schedule on run time. It can guarantee all accepted tasks' deadlines by testing the schedulability of aperiodic tasks in a busy period consisting of not only the running tasks but also the periodic tasks in future. Experimental results show that the algorithm is effective.
Partial reconfigurable system is an architecture consisting general purpose processors and FPGAs, in which FPGA can be reconfigured in run-time. Based on the architecture, software tasks and hardware tasks that are ex...
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Partial reconfigurable system is an architecture consisting general purpose processors and FPGAs, in which FPGA can be reconfigured in run-time. Based on the architecture, software tasks and hardware tasks that are executed on processor and FPGA respectively co-exist. In this paper, a real-time fault-tolerant schedulingalgorithm is proposed to schedule software/hardware hybrid tasks. In the algorithm, the sufficient condition for schedulable hybrid tasks is derived from analyzing system operation conditions when the first deadline is missed, and rollback/recovery and TMR approaches are used respectively to schedule software subtasks and hardware subtasks for fault tolerance. The experimental results demonstrate that all deadlines of accepted hybrid tasks are met and processor's utilization ratio is increased greatly compared with that of the exiting approaches when multiple faults occur.
On-demand broadcast is an attractive data dissemination method for mobile and wireless computing. In this paper, we propose a new online preemptive schedulingalgorithm, called PRDS that incorporates urgency, data siz...
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On-demand broadcast is an attractive data dissemination method for mobile and wireless computing. In this paper, we propose a new online preemptive schedulingalgorithm, called PRDS that incorporates urgency, data size and number of pending requests for real-time on-demand broadcast system. Furthermore, we use pyramid preemption to optimize performance and reduce overhead. A series of simulation experiments have been performed to evaluate the real-time performance of our algorithm as compared with other previously proposed methods. The experimental results show that our algorithm substantially outperforms other algorithms over a wide range of workloads and parameter settings.
A real-time scheduling algorithm which guarantees an optimal completion time to each job which arrives at a line of chemical tanks for a surface treatment purpose is proposed. We first consider the case when the treat...
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A real-time scheduling algorithm which guarantees an optimal completion time to each job which arrives at a line of chemical tanks for a surface treatment purpose is proposed. We first consider the case when the treatment periods are much greater than the transportation times, which allows us to neglect these times. We then extend our approach to the case when transportation times cannot be neglected. Some numerical examples are provided to illustrate this approach. (C) 2000 Elsevier Science B.V. All rights reserved.
Considering video conferencing applications, presented is the first utility accrual (or UA) real-time scheduling algorithm for multiple (m, k)-firm deadline-constrained streams running on multiprocessors, called the g...
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Considering video conferencing applications, presented is the first utility accrual (or UA) real-time scheduling algorithm for multiple (m, k)-firm deadline-constrained streams running on multiprocessors, called the global multiprocessor utility accrual schedulingalgorithm for (m, k)-firm deadline-constraint multimedia streams (or gMUA-MK). Analytical and experimental studies show that gMUA-MK achieves timeliness performance and relatively high quality of multimedia services compared to existing schemes including gMUA.
The high energy consumption has become one bottleneck in the development of the data centers (DCs), where the main energy consumers are the cooling system and the servers. Therefore, the joint optimization for the ene...
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ISBN:
(纸本)9781538616291
The high energy consumption has become one bottleneck in the development of the data centers (DCs), where the main energy consumers are the cooling system and the servers. Therefore, the joint optimization for the energy efficiency of the cooling system and the servers is a crucial problem, while most of previous works on energy saving only studies one of these two components in an isolated manner. In this paper, we propose a real-time strategy, rTCS (real-time Task Classification and scheduling strategy), to jointly optimize the energy efficiency of these two components in the scenario where the tasks arrive dynamically. Strategy rTCS first labels the tasks to classify them according to their run time and end time with a time complexity of O(1) and a bounded space complexity. Then, rTCS schedules the tasks in realtime based on their labels and the energy consumption model of the DC. Simulation results show that rTCS can effectively improve the energy efficiency of DCs.
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