407,940 research outputs found
The pros and cons of using SDL for creation of distributed services
In a competitive market for the creation of complex distributed services, time to market, development cost, maintenance and flexibility are key issues. Optimizing the development process is very much a matter of optimizing the technologies used during service creation. This paper reports on the experience gained in the Service Creation projects SCREEN and TOSCA on use of the language SDL for efficient service creation
What makes industries believe in formal methods
The introduction of formal methods in the design and development departments of an industrial company has far reaching and long lasting consequences. In fact it changes the whole environment of methods, tools and skills that determine the design culture of that company. A decision to replace current design practice by formal methods, therefore, appears a vital one and is not lightly taken. The past has shown that efforts to introduce formal methods in industry has faced a lot of controversy and opposition at various hierarchical levels in companies, resulting in a marginal spread of such methods. This paper revisits the requirements for formal description techniques and identifies some critical success and inhibiting factors associated with the introduction of formal methods in the industrial practice. One of the inhibiting factors is the often encountered lack of appropriateness of the formal model to express and manipulate the design concerns that determine the world of the engineer. This factor motivated our research in the area of architectural and implementation design concepts. The last two sections of this paper report on some results of this research
A formal support to business and architectural design for service-oriented systems
Architectural Design Rewriting (ADR) is an approach for the design of software architectures developed within Sensoria by reconciling graph transformation and process calculi techniques. The key feature that makes ADR a suitable and expressive framework is the algebraic handling of structured graphs, which improves the support for specification, analysis and verification of service-oriented architectures and applications. We show how ADR is used as a formal ground for high-level modelling languages and approaches developed within Sensoria
A design model for Open Distributed Processing systems
This paper proposes design concepts that allow the conception, understanding and development of complex technical structures for open distributed systems. The proposed concepts are related to, and partially motivated by, the present work on Open Distributed Processing (ODP). As opposed to the current ODP approach, the concepts are aimed at supporting a design trajectory with several, related abstraction levels. Simple examples are used to illustrate the proposed concepts
Pattern-based software architecture for service-oriented software systems
Service-oriented architecture is a recent conceptual framework for service-oriented software platforms. Architectures are of great importance for the evolution of
software systems. We present a modelling and transformation technique for service-centric distributed software systems. Architectural configurations, expressed through hierarchical architectural patterns, form the core of a specification and transformation technique. Patterns on different levels of abstraction form transformation invariants that structure and constrain the transformation
process. We explore the role that patterns can play in architecture transformations in terms of functional properties, but also non-functional quality aspects
Creating telecommunication services based on object-oriented frameworks and SDL
This paper describes the tools and techniques being applied in the TINA Open Service Creation Architecture (TOSCA) project to develop object-oriented models of distributed telecommunication services in SDL. The paper also describes the way in which Tree and Tabular Combined Notation (TTCN) test cases are derived from these models and subsequently executed against the CORBA-based implementations of these services through a TTCN/CORBA gateway
Graphs and Graph Transformations for Object-Oriented and Service-Oriented Systems
Theories of graphs and graph transformations form an important part of the mathematical foundations
of computing, and have been applied in a wide range of areas from the design and analysis
of algorithms to the formalization of various computer systems and programs. In this thesis, we
study how graphs and graph transformations can be used to model the static structure and dynamic
behavior of object-orientated and service-oriented systems.
Our work is mainly motivated by the difficulty in understanding and reasoning about objectorientated
and service-oriented programs, which have more sophisticated features compared with
traditional procedural programs. We show that the use of graphs and graphs transformations provides
both an intuitive visualization and a formal representation of object-orientated and serviceoriented
programs with these features, improving people’s understanding of the execution states
and behaviors of these programs.
We provide a graph-based type system, operational semantics and refinement calculus for an
object-oriented language. In this framework, we define class structures and execution states of oo
programs as directed and labeled graphs, called class graphs and state graphs, respectively. The
type system checks whether a program is well-typed based on its class graph, while the operational
semantics defines each step of program execution as a simple graph transformations between state
graphs. We show the operational semantics is type-safe in that the execution of a well-typed
program does not “go wrong”. Based on the operational semantics, we study the notion of structure
refinement of oo programs as graph transformations between their class graphs. We provide a
few groups of refinement rules for various purposes such as class expansion and polymorphism
elimination and prove their soundness and relative completeness.
We also propose a graph-based representation of service-oriented systems specified in a serviceoriented
process calculus. In this framework, we define states of service-oriented systems as hier-
archical graphs that naturally capture the hierarchical nature of service structures. For this, we
exploit a suitable graph algebra and set up a hierarchical graph model, in which graph transformations
are studied following the well-known Double-Pushout approach. Based on this model, we
provide a graph transformation system with a few sets of graph transformation rules for various
purposes such as process copy and process reduction. We prove that the graph transformation
system is sound and complete with respect to the reduction semantics of the calculus
CREOLE: a Universal Language for Creating, Requesting, Updating and Deleting Resources
In the context of Service-Oriented Computing, applications can be developed
following the REST (Representation State Transfer) architectural style. This
style corresponds to a resource-oriented model, where resources are manipulated
via CRUD (Create, Request, Update, Delete) interfaces. The diversity of CRUD
languages due to the absence of a standard leads to composition problems
related to adaptation, integration and coordination of services. To overcome
these problems, we propose a pivot architecture built around a universal
language to manipulate resources, called CREOLE, a CRUD Language for Resource
Edition. In this architecture, scripts written in existing CRUD languages, like
SQL, are compiled into Creole and then executed over different CRUD interfaces.
After stating the requirements for a universal language for manipulating
resources, we formally describe the language and informally motivate its
definition with respect to the requirements. We then concretely show how the
architecture solves adaptation, integration and coordination problems in the
case of photo management in Flickr and Picasa, two well-known service-oriented
applications. Finally, we propose a roadmap for future work.Comment: In Proceedings FOCLASA 2010, arXiv:1007.499
- …