A Compositional Semantics for Stochastic Reo Connectors

In this paper we present a compositional semantics for the channel-based coordination language Reo which enables the analysis of quality of service (QoS) properties of service compositions. For this purpose, we annotate Reo channels with stochastic delay rates and explicitly model data-arrival rates at the boundary of a connector, to capture its interaction with the services that comprise its environment. We propose Stochastic Reo automata as an extension of Reo automata, in order to compositionally derive a QoS-aware semantics for Reo. We further present a translation of Stochastic Reo automata to Continuous-Time Markov Chains (CTMCs). This translation enables us to use third-party CTMC verification tools to do an end-to-end performance analysis of service compositions.Comment: In Proceedings FOCLASA 2010, arXiv:1007.499

A Compositional Semantics for Stochastic Reo Connectors

In this paper we present a compositional semantics for the channel-based coordination language Reo which enables the analysis of quality of service (QoS) properties of service compositions. For this purpose, we annotate Reo channels with stochastic delay rates and explicitly model data-arrival rates at the boundary of a connector, to capture its interaction with the services that comprise its environment. We propose Stochastic Reo automata as an extension of Reo automata, in order to compositionally derive a QoS-aware semantics for Reo. We further present a translation of Stochastic Reo automata to Continuous-Time Markov Chains (CTMCs). This translation enables us to use third-party CTMC verification tools to do an end-to-end performance analysis of service compositions. As a case study, we are currentl

Optimal synchronization of ABD networks

We present in this paper a simple and efficient synchronizer algorithm for Asynchonous Bounded Delay Networks. In these networks each processor has a local clock, and the message delay is bounded by a known constant. The algorithm improves on an earlier synchronizer for this network model, presented by Cou et al. Moreover, using a mathematical model for this type of synchronizer, we show that the round time of new synchronizer is optimal

Combining multi-mutant and modular thermodynamic cycles to measure energetic coupling networks in enzyme catalysis

We measured and cross-validated the energetics of networks in Bacillus stearothermophilus Tryptophanyl-tRNA synthetase (TrpRS) using both multi-mutant and modular thermodynamic cycles. Multi-dimensional combinatorial mutagenesis showed that four side chains from this “molecular switch” move coordinately with the active-site Mg2+ ion as the active site preorganizes to stabilize the transition state for amino acid activation. A modular thermodynamic cycle consisting of full-length TrpRS, its Urzyme, and the Urzyme plus each of the two domains deleted in the Urzyme gives similar energetics. These dynamic linkages, although unlikely to stabilize the transition-state directly, consign the active-site preorganization to domain motion, assuring coupled vectorial behavior

Conflict of Government Policy in Tolitoli Regency, Central Sulawesi Province

This study aims to determine how the policy conflict between the Regent and Deputy Regent of Tolitoli Regency, Central Sulawesi Province. The basis of research is carried out with a qualitative approach, while the type of research is exploratory. This research was conducted in Tolitoli Regency with the basis of the problem being the conflict of Regent Moh. Saleh Bantilan with Deputy Regent ABD Rahman Hi. Buddin. In this study, it was found that the root causes of conflict were conflicts of political interest in policies and authority to organize the Bureaucratic Structure in the levels of the Tolitoli Regency Regional Government which occurred in the two periods 2010-2015 and 2015-2020. The data collection techniques used are; first, literature study, by searching literature and documents related to the scope of research. second, in-depth interviews with research informants who have been determined purposively. The results of the study revealed that there was a political policy conflict between the Regent, Moh. Saleh Bantilan with his representatives for two periods, in which Moh Saleh Bantilan monopolized the authority in carrying out his duties and functions as Regent whose authority is regulated in Regional Government Law Number 23 of 2014. And this Law does not explicitly and clearly regulate the powers and the obligations of regional heads and deputy regional heads. Thus, the Political Policy conflict occurred, as a result of the transactional political construction agreed upon by both parties when they were candidates for regent and deputy regent, and after being elected as Regent / Deputy Regent, there was a split between the Regent and his deputy. Regional Government bureaucracy does not work professionally

Formalization and Correctness of the PALS Architectural Pattern for Distributed Real-Time Systems

Many Distributed Real-Time Systems (DRTS), such as integrated modular avionics systems and distributed control systems in motor vehicles, are made up of a collection of components communicating asynchronously among themselves and with their environment that must change their state and respond to environment inputs within hard real-time bounds. Such systems are often safety-critical and need to be certi???ed; but their certi???cation is currently very hard due to their distributed nature. The Physically Asynchronous Logically Synchronous (PALS) architectural pattern can greatly reduce the design and veri???cation complexities of achieving virtual synchrony in a DTRS. This work presents a formal speci???cation of PALS as a formal model transformation that maps a synchronous design, together with a set of performance bounds of the underlying infrastructure, to a formal DRTS speci???cation that is semantically equivalent to the synchronous design. This semantic equivalence is proved, showing that the formal veri???cation of temporal logic properties of the DRTS can be reduced to their veri???cation on the much simpler synchronous design. An avionics system case study is used to illustrate the usefulness of PALS for formal verification purposes.unpublishednot peer reviewe