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In this paper we present the split-phase synchronisation technique to reduce the pessimism in the WCET analysis of parallelised hard real-time (HRT) programs on embedded multi-core processors. We implemented the split-phase synchronisation technique in the memory controller of the HRT capable MERASA multi-core processor. The split-phase synchronisation technique allows reordering memory requests and...
Driven by the evolution of modern computer architectures from uni-processor to multi-core platforms, there is an increasing need to provide light-weight, efficient, and predictable support for fine-grained parallel and distributed execution of soft real-time tasks with end-to-end timing constraints, modeled as directed a cyclic graphs whose edges capture dependences among their subtasks. At the same...
The primary goal of this work is to provide an easy and systematic way of developing safe soft real-time systems. To achieve this goal, we propose a method of generating real-time programs from formally verified models written as systems of timed automata. The models are verified using UPPAAL model checker prior to be processed by our code generators. A characteristic of our code generator is that...
Real-time locking protocols employ progress mechanism(s) to ensure that resource-holding jobs are scheduled. These mechanisms are required to bound the duration of priority-inversion blocking (pi-blocking) for jobs sharing resources. Examples of such progress mechanisms include priority inheritance and priority donation. Unfortunately, some progress mechanisms can cause any job, including those that...
Semi-partitioned scheduling has become the subject of recent interest for multiprocessors due to better utilization results, compared to conventional global and partitioned scheduling algorithms. Under semi-partitioned scheduling, a major group of tasks are assigned to fixed processors while a low number of tasks are allocated to more than one processor. Various task assigning techniques have recently...
This paper presents the model splitting method for large-scale interactive network simulation, which addresses the separation of concerns between network researchers, who focus on developing complex network models and conducting large-scale network experiments, and simulator developers, who are concerned with developing efficient simulation engines to achieve the best performance on parallel platforms...
This paper presents the first real-time multiprocessor locking protocol that supports fine-grained nested resource requests. This locking protocol relies on a novel technique for ordering the satisfaction of resource requests to ensure a bounded duration of priority inversions for nested requests. This technique can be applied on partitioned, clustered, and globally scheduled systems in which waiting...
This paper addresses the problem of scheduling periodic parallel tasks on a multi-resource platform, where tasks have real-time constraints. The goal is to exploit the inherent parallelism of a platform comprised of multiple heterogeneous resources. A resource model is proposed, which abstracts the key properties of any heterogeneous resource from a scheduling perspective. A new scheduling algorithm...
Model-based design of embedded systems using Synchronous Reactive (SR) models is among the best practices for software development in the automotive and aeronautics industry. The correct implementation of an SR model must guarantee the synchronous assumption, that is, all the system reactions complete before the next event. This assumption can be verified using schedulability analysis, but the analysis...
This paper proposes an efficient score tracking system that can track musical performance on a score in real time. This kind of technology is called score following. It can be used in wide range of applications. Our algorithm is like Dannenberg's Dynamic Programming algorithm but extends his algorithm to process polyphony music. Ideally, the notes of polyphony have to be played at the same time. But...
The synchrophasor technology has become focus of many theoretical, conceptual and practical studies lately due to an increased opportunity to improve power system reliability and security through enhanced monitoring, protection and control. The paper provides a survey of signal processing, communication and networking issues surrounding this topic so that professionals from related areas can benefit...
This paper deals with the management of a SoC-based current controller using an efficient Real-Time Operating System (RTOS). To accelerate the services of this operating system, a Real-Time Unit (RTU) was developed in VHDL and associated to the RTOS. It consists in hardware operating system that moves the scheduling and communication process from software RTOS to hardware. Thus, a significant acceleration...
In South Korea, Broadcast companies have begun a trial 3D broadcasting service by delivering dual streams, such as a left view sequence with MPEG-2 video and a right one with MPEG-4 AVC video, within the 19.4 Mbps terrestrial bandwidth. However, this limitation of transmission bandwidth in the terrestrial broadcasting system may cause quality degradation compared to the current 2D broadcasting service...
Hierarchical scheduling frameworks (HSFs) provide means for composing complex real-time systems from well-defined independently developed and analyzed subsystems. To support shared logical resources requiring mutual exclusive access in two-level HSFs, overrun without payback has been proposed as a mechanism to prevent budget depletion during resource access arbitrated by the stack resource policy...
Ethernet switches are increasingly used in real-time distributed systems as a technical solution to guarantee the timeliness in communications. However, there are still limitations related to real-time behavior caused by the limited number of priority levels and the possibility of memory overruns with consequent message losses. These limitations can be eliminated using a master/slave technique such...
Time synchronization is crucial to Wireless Sensor Networks (WSNs) due to the requirement of coordination between sensor nodes. Existing secure time synchronization protocols of WSNs introduce high overhead when used for global time synchronization. In this paper, we propose a lightweight secure global time synchronization protocol for WSNs. In the proposed protocol, a broadcast synchronization packet...
Localization of parametric defects on Analog / Mixed Signal and RF devices remains a challenge today. A very promising dynamic technique to address this issue is the parametric Variation Mapping (xVM) under Thermal Laser Stimulation (TLS). In this paper, we stress the importance of high-speed integrated solution for an efficient xVM implementation, which leads to the concept of Real-Time Variation...
Designing and verifying distributed protocols in a multi-rate asynchronous system is, in general, extremely difficult when the distributed computations require consistent input views, consistent actions and synchronized state transitions. In this paper, we address this problem and introduce a formal, complexity-reducing architectural pattern, called Multi-Rate PALS system, to support virtual synchronization...
Ethernet is a popular technology for industrial networking thanks to its low cost and high bandwidth. The current proposals to achieve real-time communication over Ethernet do not consider the determinism of the control applications resulting in inefficient use of bandwidth resources. We proposed a protocol stack architecture that works with standard Ethernet to address this problem. This paper describes...
Mixed-criticality scheduling algorithms, which attempt to reclaim system capacity lost to worst-case execution time pessimism, seem to hold great promise for multi core real-time systems, where such loss is particularly severe. However, the unique nature of these algorithms gives rise to a number of major challenges for the would-be implementer. This paper describes the first implementation of a mixed-criticality...
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