A Compositional Framework for Preference-Aware Agents

A formal description of a Cyber-Physical system should include a rigorous specification of the computational and physical components involved, as well as their interaction. Such a description, thus, lends itself to a compositional model where every module in the model specifies the behavior of a (computational or physical) component or the interaction between different components. We propose a framework based on Soft Constraint Automata that facilitates the component-wise description of such systems and includes the tools necessary to compose subsystems in a meaningful way, to yield a description of the entire system. Most importantly, Soft Constraint Automata allow the description and composition of components' preferences as well as environmental constraints in a uniform fashion. We illustrate the utility of our framework using a detailed description of a patrolling robot, while highlighting methods of composition as well as possible techniques to employ them.Comment: In Proceedings V2CPS-16, arXiv:1612.0402

The Evolution of Jolie: From Orchestrations to Adaptable Choreographies

International audienceJolie is an orchestration language conceived during Sensoria, an FP7 European project led by Martin Wirsing in the time frame 2005– 2010. Jolie was designed having in mind both the novel –at project time– concepts related to Service-Oriented Computing and the traditional approach to the modelling of concurrency typical of process calculi. The foundational work done around Jolie during Sensoria has subsequently produced many concrete results. In this paper we focus on two distinct advancements, one aiming at the development of dynamically adaptable orchestrated systems and one focusing on global choreographic specifications. These works, more recently, contributed to the realisation of a framework for programming dynamically evolvable distributed Service-Oriented applications that are correct-by-construction

Service Composition for Collective Adaptive Systems

Collective adaptive systems are large-scale resource-sharing systems which adapt to the demands of their users by redistributing resources to balance load or provide alternative services where the current provision is perceived to be insufficient. Smart transport systems are a primary example where real-time location tracking systems record the location availability of assets such as cycles for hire, or fleet vehicles such as buses, trains and trams. We consider the problem of an informed user optimising his journey using a composition of services offered by different service providers

A Component-oriented Framework for Autonomous Agents

The design of a complex system warrants a compositional methodology, i.e., composing simple components to obtain a larger system that exhibits their collective behavior in a meaningful way. We propose an automaton-based paradigm for compositional design of such systems where an action is accompanied by one or more preferences. At run-time, these preferences provide a natural fallback mechanism for the component, while at design-time they can be used to reason about the behavior of the component in an uncertain physical world. Using structures that tell us how to compose preferences and actions, we can compose formal representations of individual components or agents to obtain a representation of the composed system. We extend Linear Temporal Logic with two unary connectives that reflect the compositional structure of the actions, and show how it can be used to diagnose undesired behavior by tracing the falsification of a specification back to one or more culpable components

A logic for n-dimensional hierarchical refinement

Hierarchical transition systems provide a popular mathematical structure to represent state-based software applications in which different layers of abstraction are represented by inter-related state machines. The decomposition of high level states into inner sub-states, and of their transitions into inner sub-transitions is common refinement procedure adopted in a number of specification formalisms. This paper introduces a hybrid modal logic for k-layered transition systems, its first-order standard translation, a notion of bisimulation, and a modal invariance result. Layered and hierarchical notions of refinement are also discussed in this setting.Comment: In Proceedings Refine'15, arXiv:1606.0134

A Rewriting Framework for Interacting Cyber-Physical Agents

The analysis of cyber-physical systems (CPS) is challenging due to the large state space and the continuous changes occurring in their constituent parts. Design practices favor modularity to help reducing this complexity. In a previous work, we proposed a discrete semantic model for CPS that captures both cyber and physical aspects as streams of discrete observations, which ultimately form the behavior of a component. This semantic model is denotational and compositional, where each composition operator algebraically models an interaction between a pair of components. In this paper, we propose a specification of components as rewrite systems. The specification is operational and executable, and we study conditions for its semantics as components to be compositional. We demonstrate our framework by modeling a coordination of robots moving on a shared field. We show that our system of robots can be coordinated by a protocol in order to exhibit a desired emerging behavior. We use an implementation of our framework in Maude to give practical results

Synthesis of models for order-sorted first-order theories using linear algebra and constraint solving

[EN] Recent developments in termination analysis for declarative programs emphasize the use of appropriate models for the logical theory representing the program at stake as a generic approach to prove termination of declarative programs. In this setting, Order-Sorted First-Order Logic provides a powerful framework to represent declarative programs. It also provides a target logic to obtain models for other logics via transformations. We investigate the automatic generation of numerical models for order-sorted first-order logics and its use in program analysis, in particular in termination analysis of declarative programs. We use convex domains to give domains to the different sorts of an order-sorted signature; we interpret the ranked symbols of sorted signatures by means of appropriately adapted convex matrix interpretations. Such numerical interpretations permit the use of existing algorithms and tools from linear algebra and arithmetic constraint solving to synthesize the models.Partially supported by the EU (FEDER), Spanish MINECO TIN 2013-45732-C4-1-P and GV PROMETEOII/2015/013Lucas Alba, S. (2015). Synthesis of models for order-sorted first-order theories using linear algebra and constraint solving. Electronic Proceedings in Theoretical Computer Science. 200:32-47. https://doi.org/10.4204/EPTCS.200.3S324720