695 research outputs found
Tau Be or not Tau Be? - A Perspective on Service Compatibility and Substitutability
One of the main open research issues in Service Oriented Computing is to
propose automated techniques to analyse service interfaces. A first problem,
called compatibility, aims at determining whether a set of services (two in
this paper) can be composed together and interact with each other as expected.
Another related problem is to check the substitutability of one service with
another. These problems are especially difficult when behavioural descriptions
(i.e., message calls and their ordering) are taken into account in service
interfaces. Interfaces should capture as faithfully as possible the service
behaviour to make their automated analysis possible while not exhibiting
implementation details. In this position paper, we choose Labelled Transition
Systems to specify the behavioural part of service interfaces. In particular,
we show that internal behaviours (tau transitions) are necessary in these
transition systems in order to detect subtle errors that may occur when
composing a set of services together. We also show that tau transitions should
be handled differently in the compatibility and substitutability problem: the
former problem requires to check if the compatibility is preserved every time a
tau transition is traversed in one interface, whereas the latter requires a
precise analysis of tau branchings in order to make the substitution preserve
the properties (e.g., a compatibility notion) which were ensured before
replacement.Comment: In Proceedings WCSI 2010, arXiv:1010.233
Analysis and Verification of Service Interaction Protocols - A Brief Survey
Modeling and analysis of interactions among services is a crucial issue in
Service-Oriented Computing. Composing Web services is a complicated task which
requires techniques and tools to verify that the new system will behave
correctly. In this paper, we first overview some formal models proposed in the
literature to describe services. Second, we give a brief survey of verification
techniques that can be used to analyse services and their interaction. Last, we
focus on the realizability and conformance of choreographies.Comment: In Proceedings TAV-WEB 2010, arXiv:1009.330
Dynamic System Adaptation by Constraint Orchestration
For Paradigm models, evolution is just-in-time specified coordination
conducted by a special reusable component McPal. Evolution can be treated
consistently and on-the-fly through Paradigm's constraint orchestration, also
for originally unforeseen evolution. UML-like diagrams visually supplement such
migration, as is illustrated for the case of a critical section solution
evolving into a pipeline architecture.Comment: 19 page
Model-based Adaptation of Behavioural Mismatching Components
International audienceComponent-Based Software Engineering focuses on the reuse of existing software components. In practice, most components cannot be integrated directly into an application-to-be, because they are incompatible. Software Adaptation aims at generating, as automatically as possible, adaptors to compensate mismatch between component interfaces, and is therefore a promising solution for the development of a real market of components promoting software reuse. In this article, we present our approach for software adaptation which relies on an abstract notation based on synchronous vectors and transition systems for governing adaptation rules. Our proposal is supported by dedicated algorithms that generate automatically adaptor protocols. These algorithms have been implemented in a tool, called Adaptor, that can be used through a user-friendly graphical interface
Interactive specification and verification of behavioral adaptation contracts
International audienceContext. Adaptation is a crucial issue when building new applications by reusing existing software services which were not initially designed to interoperate with each other. Adaptation contracts describe composition constraints and adaptation requirements among these services. The writing of this specification by a designer is a difficult and error-prone task, especially when interaction protocols are considered in service interfaces. Objective. In this article, we propose a tool-based, interactive approach to support the contract design process. Method. Our approach includes: (i) a graphical notation to define port bindings, and an interface compatibility measure to compare protocols and suggest some port connections to the designer, (ii) compositional and hierarchical techniques to facilitate the specification of adaptation contracts by building them incrementally, (iii) validation and verification techniques to check that the contract will make the involved services work correctly and as expected by the designer. Results. Our results show a reduction both in the amount of effort that the designer has to put into building the contract, as well as in the number of errors present in the final result (noticeably higher in the case of manual specification). Conclusion. We conclude that it is important to provide integrated tool support for the specification and verification of adaptation contracts, since their incorrect specification induces erroneous executions of the system. To the best of our knowledge, such tool support has not been provided by any other approach so far, and hence we consider the techniques described in this paper as an important contribution to the area of behavioral software adaptation
Flooding-Based Algorithm for Behavioural Compatibility Measuring
Nowadays, large software systems are mostly built using existing services. These are not always designed to interact, i.e., their public interfaces often present some mismatches. Checking compatibility of service interfaces allows one to avoid erroneous executions when composing the services and ensures correct reuse and interaction. Service compatibility has been intensively studied, in particular for discovery purposes, but most of existing approaches return a Boolean result. In this paper, we present a quantitative approach for measuring the compatibility degree of service interfaces. Our method is generic and flooding-based, and fully automated by a prototype tool
An Aspect-Oriented Approach for Supporting Autonomic Reconfiguration of Software Architecture
The increasing complexity of current software systems is encouraging the development of self-managed software architectures, i.e. systems capable of reconfiguring their structure at runtime to fulfil a set of goals. Several approaches have covered different aspects of their development, but some issues remain open, such as the maintainability or the scalability of self-management subsystems. Centralized approaches, like self-adaptive architectures, offer good maintenance properties but do not scale well for large systems. On the contrary, decentralized approaches, like self-organising architectures, offer good scalability but are not maintainable: reconfiguration specifications are spread and often tangled with functional specifications. In order to address these issues, this paper presents an aspect-oriented autonomic reconfiguration approach where: (1) each subsystem is provided with self-management properties so it can evolve itself and the components that it is composed of; (2) self-management concerns are isolated and encapsulated into aspects, thus improving its reuse and maintenance. Povzetek: Predstavljen je pristop s samo-preoblikovanjem programske arhitekture
Formalizing Adaptation On-the-Fly
AbstractParadigm models specify coordination of collaborating components via constraint control. Component McPal allows for later addition of new constraints and new control in view of unforeseen adaptation. After addition McPal starts coordinating migration accordingly, adapting the system towards to-be collaboration. Once done, McPal removes obsolete control and constraints. All coordination remains ongoing while migrating on-the-fly, being deflected without any quiescence. Through translation into process algebra, supporting formal analysis is arranged carefully, showing that as-is and to-be processes are proper abstractions of the migrating process. A canonical critical section problem illustrates the approach
A comparative study of process mediator components that support behavioral incompatibility
Most businesses these days use the web services technology as a medium to
allow interaction between a service provider and a service requestor. However,
both the service provider and the requestor would be unable to achieve their
business goals when there are miscommunications between their processes. This
research focuses on the process incompatibility between the web services and
the way to automatically resolve them by using a process mediator. This paper
presents an overview of the behavioral incompatibility between web services and
the overview of process mediation in order to resolve the complications faced
due to the incompatibility. Several state-of the-art approaches have been
selected and analyzed to understand the existing process mediation components.
This paper aims to provide a valuable gap analysis that identifies the
important research areas in process mediation that have yet to be fully
explored.Comment: 20 Pages, 9 figures and 8 Tables; International Journal on Web
Service Computing (IJWSC), September 2011, Volume 2, Number
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