A Layered Implementation of DR-BIP Supporting Run-Time Monitoring and Analysis

International audienceReconfigurable systems are emerging in many application domains as reconfiguration can be used to cope with unpredictable system environments and adapt by delivering new functionality. The Dynamic Reconfigurable BIP (DR-BIP) framework is an extension of the BIP component framework enriched with dynamic exogenous reconfiguration primitives, intended to support rigorous modeling of reconfigurable systems. We present a new two-layered implementation of DR-BIP clearly separating between execution of reconfiguration operations and execution of a fixed system configuration. Such a separation of concerns offers the advantage of using the mature and efficient BIP engine as well as existing associated analysis and verification tools. Another direct benefit of the new implementation is the possibility to monitor a holistic view of a system's behavior captured as a set of traces involving information about both the state of the system components and the dynamically changing architecture. Monitoring and analyzing such traces poses interesting questions regarding the formalization and runtime verification of properties of reconfigurable systems

Mixed-Valence Cations of Di(carbazol-9-yl) Biphenyl, Tetrahydropyrene, and Pyrene Derivatives

Although bis­(diarylamino) mixed-valence radical cations have been quite extensively studied, their bis­(carbazolyl) analogues have not, even though the hole-transporting properties of species such as of 4,4′-bis­(9<i>H</i>-carbazol-9-yl)-1,1′-biphenyl, CBP, are widely exploited in organic light-emitting diodes. This work reports the generation by chemical oxidation of the radical cations of 4,4′-bis­(3,6-di-<i>tert</i>-butyl-9<i>H</i>-carbazol-9-yl)-1,1′-biphenyl (a model for the unstable radical cation of CBP), 2,7-bis­(3,6-di-<i>tert</i>-butyl-9<i>H</i>-carbazol-9-yl)-4,5,9,10-tetrahydropyrene, and 2,7-bis­(3,6-di-<i>tert</i>-butyl-9<i>H</i>-carbazol-9-yl)­pyrene. The visible and near-IR spectra of these cations have been compared to those of the corresponding dication spectra, to the spectrum of the 3,6-di-<i>tert</i>-butyl-9-(4-(<i>tert</i>-butyl)­phenyl)-9<i>H</i>-carbazole radical cation, and to the results of time-dependent density-functional calculations. The biphenyl- and pyrene-bridged species are found to be localized (class-II) mixed-valence compounds, whereas stronger coupling between the redox centers in the tetrahydropyrene-bridged radical cation results in a delocalized (class-III) species. For all three radical cations, the electronic couplings are lower than those obtained for delocalized 4,4′-bis­(diarylamino)-1,1′-biphenyl radical cations

A Formal Model to Integrate Behavioral and Structural Adaptations in Self-adaptive Systems

Part 1: Agent Based SystemsInternational audienceAn approach for modelling adaptive complex systems should be flexible and scalable to allow a system to grow easily, and should have a formal foundation to guarantee the correctness of the system behavior. In this paper, we present the architecture, and formal syntax and semantics of HPobSAM which is a model for specifying behavioral and structural adaptations to model large-scale systems and address re-usability concerns. Self-adaptive modules are used as the building blocks to structure a system, and policies are used as the mechanism to perform both behavioral and structural adaptations. While a self-adaptive module is autonomous to achieve its local goals by collaborating with other self-adaptive modules, it is controlled by a higher-level entity to prevent undesirable behavior. HPobSAM is formalized using a combination of algebraic, graph transformation-based and actor-based formalisms