3,838 research outputs found
Towards a connector algebra
Abstract. Interoperability of heterogeneous networked systems has yet to reach the maturity required by ubiquitous computing due to the technology-dependent nature of solutions. The Connect Integrated Project attempts to develop a novel network infrastructure to allow heterogeneous networked systems to freely communicate with one another by synthesising the required connectors on-the-fly. A key objective of Connect is to build a comprehensive theory of composable connectors, by devising an algebra for rigorously characterising complex interaction protocols in order to support automated reasoning. With this aim in mind, we formalise a high-level algebra for reasoning about protocol mismatches. Basic mismatches can be solved by suitably defined primitives, while complex mismatches can be settled by composition operators that build connectors out of simpler ones. The semantics of the algebra is given in terms of Interface Automata, and an example in the domain of instant messaging is used to illustrate how the algebra can characterise the interaction behaviour of a connector for mediating protocols
Domain and range for angelic and demonic compositions
We give finite axiomatizations for the varieties generated by representable
domain--range algebras when the semigroup operation is interpreted as angelic
or demonic composition, respectively
Components Interoperability through Mediating Connector Patterns
A key objective for ubiquitous environments is to enable system
interoperability between system's components that are highly heterogeneous. In
particular, the challenge is to embed in the system architecture the necessary
support to cope with behavioral diversity in order to allow components to
coordinate and communicate. The continuously evolving environment further asks
for an automated and on-the-fly approach. In this paper we present the design
building blocks for the dynamic and on-the-fly interoperability between
heterogeneous components. Specifically, we describe an Architectural Pattern
called Mediating Connector, that is the key enabler for communication. In
addition, we present a set of Basic Mediator Patterns, that describe the basic
mismatches which can occur when components try to interact, and their
corresponding solutions.Comment: In Proceedings WCSI 2010, arXiv:1010.233
Extended Connectors: Structuring Glue Operators in BIP
Based on a variation of the BIP operational semantics using the offer
predicate introduced in our previous work, we extend the algebras used to model
glue operators in BIP to encompass priorities. This extension uses the Algebra
of Causal Interaction Trees, T(P), as a pivot: existing transformations
automatically provide the extensions for the Algebra of Connectors. We then
extend the axiomatisation of T(P), since the equivalence induced by the new
operational semantics is weaker than that induced by the interaction semantics.
This extension leads to canonical normal forms for all structures and to a
simplification of the algorithm for the synthesis of connectors from Boolean
coordination constraints.Comment: In Proceedings ICE 2013, arXiv:1310.401
Tangle and Brauer Diagram Algebras of Type Dn
A generalization of the Kauffman tangle algebra is given for Coxeter type Dn.
The tangles involve a pole or order 2. The algebra is shown to be isomorphic to
the Birman-Murakami-Wenzl algebra of the same type. This result extends the
isomorphism between the two algebras in the classical case, which in our
set-up, occurs when the Coxeter type is of type A with index n-1. The proof
involves a diagrammatic version of the Brauer algebra of type Dn in which the
Temperley-Lieb algebra of type Dn is a subalgebra.Comment: 33 page
Contractors for flows
We answer a question raised by Lov\'asz and B. Szegedy [Contractors and
connectors in graph algebras, J. Graph Theory 60:1 (2009)] asking for a
contractor for the graph parameter counting the number of B-flows of a graph,
where B is a subset of a finite Abelian group closed under inverses. We prove
our main result using the duality between flows and tensions and finite Fourier
analysis. We exhibit several examples of contractors for B-flows, which are of
interest in relation to the family of B-flow conjectures formulated by Tutte,
Fulkerson, Jaeger, and others.Comment: 22 pages, 1 figur
Connectors meet Choreographies
We present Cho-Reo-graphies (CR), a new language model that unites two
powerful programming paradigms for concurrent software based on communicating
processes: Choreographic Programming and Exogenous Coordination. In CR,
programmers specify the desired communications among processes using a
choreography, and define how communications should be concretely animated by
connectors given as constraint automata (e.g., synchronous barriers and
asynchronous multi-casts). CR is the first choreography calculus where
different communication semantics (determined by connectors) can be freely
mixed; since connectors are user-defined, CR also supports many communication
semantics that were previously unavailable for choreographies. We develop a
static analysis that guarantees that a choreography in CR and its user-defined
connectors are compatible, define a compiler from choreographies to a process
calculus based on connectors, and prove that compatibility guarantees
deadlock-freedom of the compiled process implementations
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Better abstractions for reusable components & architectures
Software architecture (SA) is a crucial component of Model Driven Engineering (MDE), since it eases the communication and reuse of designs and components. However, existing languages (e.g., UML, AADL, SysML) are lacking many needed features. In particular, they provide rudimentary support for connectors, a first-class element in the components and connectors (C&C) architectural view and one of the most reusable architectural elements. This is unfortunate, since the difficult properties that need to be guaranteed for complex systems are mainly the non-functional properties, like throughput, security and dependability, which are greatly influenced by the employed connectors. This work reviews the basic abstractions of the C&C view of SA and examines extra architectural elements which can support the detailed, explicit and separate description of behaviour, interaction and control logic
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