QCOF: New RPL Extension for QoS and Congestion-Aware in Low Power and Lossy Network

Low power and lossy networks (LLNs) require a routing protocol under real-time and energy constraints, congestion aware and packet priority. Thus, Routing Protocol for Low power and lossy network (RPL) is recommended by Internet Engineering Task force (IETF) for LLN applications. In RPL, nodes select their optimal paths towards their preferred parents after meeting routing metrics that are injected in the objective function (OF). However, RPL did not impose any routing metric and left it open for implementation. In this paper, we propose a new RPL objective function which is based on the quality of service (QoS) and congestion-aware. In the case paths fail, we define new RPL control messages for enriching the network by adding more routing nodes. Extensive simulations show that QCOF achieves significant improvement in comparison with the existing objective functions, and appropriately satisfies real-time applications under QoS and network congestion.info:eu-repo/semantics/publishedVersio

Component based deployment of industrial control systems: a hybrid scheduling approach

This paper deals with the IEC 61499 standard. A function block (FB) is an event triggered component and an application is a distributed FBs network on several devices. We consider these devices as multi-tasking PLCs. To validate the temporal behavior inside a device, we propose a hybrid scheduling approach combining off-line and on-line policies. This approach transforms application blocks into tasks thanks to the off-line policy. Then, it checks their required on-line feasibility. On the other hand, we propose also a temporal charcaterization of exchanged messages between devices to check also their online feasibility

Cyber-OF: An Adaptive Cyber-Physical Objective Function for Smart Cities Applications

Work in Progress Session, 28th Euromicro Conference on Real-Time Systems (ECRTS 2016). 5 to 8, Jul, 2016. Toulouse, France.RPL is the standard routing protocol for the Internet of Things. It is designed for low-power and lossy networks. Several works designed different objective functions for RPL to optimize routing decisions for a particular category of applications. However, these objective functions do not take into account the cyber-physical properties of the environment. In addition, they are tailored to satisfy a particular application requirement (e.g. energy efficiency or delay), so are not adaptive to possible changes of data criticality. This paper improves on the state-of-the-art with the design of a cyber-physical objective function tailored for smart city applications, that addresses the aforementioned gaps. Initial simulation results demonstrate the effectiveness of Cyber-OF in coping with dynamic changes of the criticality of events data and in providing a good performance trade-off between conflicting performance metrics, namely energy.info:eu-repo/semantics/publishedVersio

Multi-agent Adaptive Architecture for Flexible Distributed Real-time Systems

Recent critical embedded systems become more and more complex and usually react to their environment that requires to amend their behaviors by applying run-time reconfiguration scenarios. A system is defined in this paper as a set of networked devices, where each of which has its own operating system, a processor to execute related periodic software tasks, and a local battery. A reconfiguration is any operation allowing the addition-removal-update of tasks to adapt the device and the whole system to its environment. It may be a reaction to a fault or even optimization of the system functional behavior. Nevertheless, such scenario can cause the violation of real-time or energy constraints, which is considered as a critical run-time problem. We propose a multi-agent adaptive architecture to handle dynamic reconfigurations and ensure the correct execution of the concurrent real-time distributed tasks under energy constraints. The proposed architecture integrates a centralized scheduler agent (ScA) which is the common decision making element for the scheduling problem. It is able to carry out the required run-time solutions based on operation research techniques and mathematical tools for the system's feasibility. This architecture assigns also a reconfiguration agent (RA p ) to each device p to control and handle the local reconfiguration scenarios under the instructions of ScA. A token-based protocol is defined in this case for the coordination between the different distributed agents in order to guarantee the whole system's feasibility under energy constraints.info:eu-repo/semantics/publishedVersio

A degraded scheduling generation of a component based application

This paper deals with control applications designed using the component-based standard IEC 61499. In this standard, a function block is an event triggered component and an application is a function blocks network. Supposing end to end delays on applications behavior, the hard temporal validation of FBs networks may be not feasible. We propose to weaken these delays by tolerance constraints deduced from specifications. Exploiting the (m, k) model to specify these constraints, we propose a schedulability analysis generating a degraded scheduling to use by a sequencer at run-time

A hybrid scheduling approach of centralized component based control applications

http://ieeexplore.ieee.org/This paper deals with the component based standard IEC 61499. A function block (FB) is an event triggered component and an application is a network of FBs. This network is centralized in a multi-tasking PLC. To validate the temporal behavior of the application blocks, we propose a hybrid scheduling approach combining off-line and on-line policies. The off-line policy allows to generate pre-schedulings for FBs. We associate one pre-scheduling to one task of the PLC. We apply then an existing schedulability condition to check the feasibility of these tasks

A static scheduling generator for the deployment of a component based application

This paper proposes a static scheduling of an application designed using the IEC 61499 standard. In this standard, a function block (FB) is an event triggered component and an application is a FBs network. According to specifications, we propose temporal constraints on the application behavior. To verify these constraints, we propose to transform the application blocks into a particular tasks system with precedence constraints. The purpose is to exploit previous works on scheduling. In addition, we propose a schedulability analysis generating an accessibility graph of the application. This graph allows the construction of a static scheduling to use by a sequencer at run-time