A Compositional Scheduling Framework for Digital Avionics Systems

Easwaran, Arvind; Lee, Insup; Sokolsky, Oleg; Vestal, Steve

doi:10.1109/rtcsa.2009.46

Cited by 56 publications

(57 citation statements)

References 19 publications

(40 reference statements)

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“…This is achieved by using data concentrators that receive data from nearby sensors or other equipment on a many to one principle and then forward an assembled complex message to the final destination (cockpit) on a single cable. Different message have different periodicity or may even be aperiodic which requires the use of the concept of scheduler that is subject to intense research such as in [11] [22] [23]. It is the scheduler that computes sequence numbers.…”

Section: Fig 6 Concrete Layer Architecture For Periodic Messagesmentioning

confidence: 99%

Challenges of Testing Periodic Messages in Avionics Systems Using TTCN-3

Stepien

Peyton

2013

Testing Software and Systems

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Abstract. The TTCN-3 language was conceived initially for testing telecommunications protocols that consist of sequences of discrete messages between communicating entities. TTCN-3 has a clear model of separation of concerns between an abstract layer, where test behavior is specified, and a concrete layer, where messages are encoded / decoded and sent and received to/from the system under test. This model, however, is cumbersome for testing protocols with periodic messages as used in avionics systems. This paper presents an innovative approach to addressing issues involving periodic messages in TTCN-3, based on our experiences working with avionics systems. Extensions to the TTCN-3 standard are proposed, based on our approach. We also demonstrate how the approach can be used for test system certification and requirements verification for avionics systems.

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Section: Fig 6 Concrete Layer Architecture For Periodic Messagesmentioning

confidence: 99%

Challenges of Testing Periodic Messages in Avionics Systems Using TTCN-3

Stepien

Peyton

2013

Testing Software and Systems

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“…If periods are harmonic, it will be possible to apply optimal fault tolerant mechanisms as mentioned in Kwak and Yang (2012). In the integrated modular avionics (IMA), harmonic periods facilitate the problem of assigning tasks to the partition servers (Easwaran et al 2009). Consequently, they reduce the size of the hyperperiod which facilitates the construction and storage of the offline schedule table used in IMA systems because then a smaller portion of RAM (or flash memory) of the system is consumed by the offline table.…”

Section: Introductionmentioning

confidence: 99%

Optimal harmonic period assignment: complexity results and approximation algorithms

Mohaqeqi

Nasri

et al. 2018

Real-Time Syst

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Harmonic periods have wide applicability in industrial real-time systems. Rate monotonic (RM) is able to schedule task sets with harmonic periods up to 100% utilization. Also, if there is no release jitter and execution time variation, RM and EDF generate the same schedule for each instance of a task. As a result, all instances of a task are interfered by the same amount of workload. This property decreases the jitters that happen during sampling and actuation of the tasks, and hence, it increases the quality of service in control systems. In this paper, we consider the problem of optimal period assignment where the periods are constrained to be harmonic and the task set is required to be feasible. We study two variants of this problem. In the first one, the objective is to maximize the system utilization, while in the second one, the 831 goal is to minimize the total weighted sum of the periods. First, we assume that an interval is determined a priori for each task from which its period can be selected. We show that both variants of the problem are (at least) weakly NP-hard. This is shown by reducing the NP-complete number partitioning problem to the mentioned harmonic period assignment problems. Afterwards, we consider a variant of the second problem in which the periods are not restricted to a special interval. We present two approximation algorithms with polynomial-time complexity for this problem and show that the maximum relative error of these algorithms is bounded by a factor of 1.125. Our evaluations show that, on the average, results of the approximation algorithms are very close to an optimal solution.

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“…[4]- [6], and [7] formally analyze the schedulability of hierarchical real-time systems with the compositional analysis approach. The compositional analysis approach is used for partitioning a huge hierarchical system into subsystems, and each partition is separately verified as whether it is always schedulable.…”

Section: Introductionmentioning

confidence: 99%

“…They prove that if all subsystems are always schedulable, then the entire system is always schedulable. [6] and [7] specify shared resources such as semaphore or message passing and verify a system that includes them. systems efficiently.…”

Section: Introductionmentioning

confidence: 99%