This article has been accepted for inclusion in a future issue of this journal. Content is final as presented, with the exception of pagination. IEEE TRANSACTIONS ON SYSTEMS, MAN, AND CYBERNETICS: SYSTEMS 1 R-Node: New Pipelined Approach for an Effective Reconﬁgurable Wireless Sensor Node Maroua Gasmi, Olfa Mosbahi, Mohamed Khalgui, Luis Gomes, and Zhiwu Li, Fellow, IEEE Abstract—The pipeline of reconﬁguration is a novel approach that gives a decision making mechanism for any system of tasks when several reconﬁguration scenarios are required. These sce- narios represent the run-time operations that allow automatic functional modiﬁcation of the system behavior. In the case of their frequent income, the pipeline follows a speciﬁc set of steps in order to ﬁgure out the scenarios that need to be applied with- out altering its own performance. The steps are represented by a sequence of modules. The ﬁrst module checks the availability of the resources needed by the tasks. The second maintains the stability by rejecting any insupportable ﬂow of software reconﬁg- urations that can destabilize a system. The third module checks the availability of memory for each software reconﬁguration request, whereas the fourth veriﬁes the availability of energy for the execution of a new system software conﬁguration. The last module checks the schedulability of this conﬁguration by changing the priorities of the ﬁnally accepted tasks in order to reduce their response and blocking times, and to meet their dead- lines. The feasibility of the reconﬁguration through this approach allows its implementation in wireless sensor nodes. Known by their important requirements in terms of memory and energy, this proposition is adequate when it comes to guaranteeing a maximum lifespan of the nodes. Therefore, the pipeline of recon- ﬁguration is integrated as a middleware within the software architecture of a node. The functionality of this middleware is coordinated by the mean of a set of threads that manage the communication between the pipeline of reconﬁguration and the operating system. A tool has been developed within LISI Manuscript received June 14, 2016; accepted October 19, 2016. This work was supported by the MOBIDOC from the European Commission and the Science and Technology Development Fund, MSAR, under Grant 078/2015/A3. This paper is a collaboration between LISI Laboratory, INSAT, University of Carthage, Tunisia, PASRI, Ministry of High Study and Research, Tunisia, and Universidade Nova de Lisboa, Portugal. This paper was recom- mended by Associate Editor H. Tianﬁeld. M. Gasmi is with the Faculty of Mathematics, Physical and Natural Sciences, University Tunis-El Manar, Tunis 2092, Tunisia, and also with the National Institute of Applied Sciences and Technology, University of Carthage, Tunis 1080, Tunisia (e-mail: mra.gsm@gmail.com). O. Mosbahi is with the National Institute of Applied Sciences and Technology, University of Carthage, Tunis 1080, Tunisia (e-mail: olfamosbahi@gmail.com). M. Khalgui is with the School of Electro-Mechanical Engineering, Xidian University, Xi’an 710071, China, and the National Institute of Applied Sciences and Technology, University of Carthage, Tunis 1080, Tunisia (e-mail: khalgui.mohamed@gmail.com). L. Gomes is with the Universidade Nova de Lisboa-FCT-DEE and UNINOVA-CTS, P-2829-516 Monte de Caparica, Portugal (e-mail: lugo@fct.unl.pt). Z. Li is with the Institute of Systems Engineering, Macau University of Science and Technology, Macau 999078, China, and also with the School of Electro-Mechanical Engineering, Xidian University, Xi’an 710071, China (e-mail: zhwli@xidian.edu.cn). Color versions of one or more of the ﬁgures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identiﬁer 10.1109/TSMC.2016.2625817 Laboratory to encode this proposition and show its impact on a large range of real devices under diversiﬁed scenarios of reconﬁgurations. Index Terms—Energy, memory, real-time system, software reconﬁguration, wireless sensor network (WSN). NOMENCLATURE β Set of reconﬁgurations dependent on Reconf.  R (t) Set of resources to be removed from a system at time t.  Sys (t) Set of tasks to be removed from a system at time t. η Action performed by the reconﬁguration Reconf. Ŵ Set of all the tasks in Reconf.  R (t 1 ) Set of tasks which cannot be removed at time t 1 . ρ E Set of accepted tasks in the module of energy. ρ M Set of accepted tasks in the module of memory. ρ R Set of accepted tasks modiﬁed through the module of RPCP. ρ SC Set of accepted reconﬁgurations in the module of system checking. ρ S Set of accepted reconﬁgurations in the module of stability. σ Set of possible resources that can be used by τ i . τ i Real-time task. τ A i Arrival time of τ i . τ C i Worst case execution time of τ i . τ D i Deadline of τ i . τ E i End of execution of τ i . τ R i Response time of τ i . τ S i Start of execution of τ i . τ T i Period of τ i . τ W i Work left for τ i . τ π(t) i State of τ i within a system (1 if τ i is active either executed or not, 0 else). τ Cond(t) i State of condition (1 if the condition that acti- vates τ i is met at t, 0 if not). τ Req(t) i Set of resources required by τ i at t. τ Res(t) i Set of resources used by τ i at t. τ prior Set of tasks except the least prioritized. τ Sys Set of all possible tasks that may be executed within a system. τ Sys (t) Set of all possible tasks that may be executed within a system at time t. θ Priority of reconﬁguration Reconf. 2168-2216 c  2016 IEEE. 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