96,098 research outputs found
A Model of Layered Architectures
Architectural styles and patterns play an important role in software
engineering. One of the most known ones is the layered architecture style.
However, this style is usually only stated informally, which may cause problems
such as ambiguity, wrong conclusions, and difficulty when checking the
conformance of a system to the style. We address these problems by providing a
formal, denotational semantics of the layered architecture style. Mainly, we
present a sufficiently abstract and rigorous description of layered
architectures. Loosely speaking, a layered architecture consists of a hierarchy
of layers, in which services communicate via ports. A layer is modeled as a
relation between used and provided services, and layer composition is defined
by means of relational composition. Furthermore, we provide a formal definition
for the notions of syntactic and semantic dependency between the layers. We
show that these dependencies are not comparable in general. Moreover, we
identify sufficient conditions under which, in an intuitive sense which we make
precise in our treatment, the semantic dependency implies, is implied by, or
even coincides with the reflexive-transitive closure of the syntactic
dependency. Our results provide a technology-independent characterization of
the layered architecture style, which may be used by software architects to
ensure that a system is indeed built according to that style.Comment: In Proceedings FESCA 2015, arXiv:1503.0437
Architectures in parametric component-based systems: Qualitative and quantitative modelling
One of the key aspects in component-based design is specifying the software
architecture that characterizes the topology and the permissible interactions
of the components of a system. To achieve well-founded design there is need to
address both the qualitative and non-functional aspects of architectures. In
this paper we study the qualitative and quantitative formal modelling of
architectures applied on parametric component-based systems, that consist of an
unknown number of instances of each component. Specifically, we introduce an
extended propositional interaction logic and investigate its first-order level
which serves as a formal language for the interactions of parametric systems.
Our logics achieve to encode the execution order of interactions, which is a
main feature in several important architectures, as well as to model recursive
interactions. Moreover, we prove the decidability of equivalence,
satisfiability, and validity of first-order extended interaction logic
formulas, and provide several examples of formulas describing well-known
architectures. We show the robustness of our theory by effectively extending
our results for parametric weighted architectures. For this, we study the
weighted counterparts of our logics over a commutative semiring, and we apply
them for modelling the quantitative aspects of concrete architectures. Finally,
we prove that the equivalence problem of weighted first-order extended
interaction logic formulas is decidable in a large class of semirings, namely
the class (of subsemirings) of skew fields.Comment: 53 pages, 11 figure
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