Improving the Quality of Distributed Composite Service Applications

Dynamic service composition promotes the on-the-fly creation of value-added applications by combining services. Large scale, dynamic distributed applications, like those in the pervasive computing domain, pose many obstacles to service composition such as mobility, and resource availability. In such environments, a huge number of possible composition configurations may provide the same functionality, but only some of those may exhibit the desirable non-functional qualities (e.g. low battery consumption and response time) or satisfy users\u27 preferences and constraints. The goal of a service composition optimiser is to scan the possible composition plans to detect these that are optimal in some sense (e.g. maximise availability or minimise data latency) with acceptable performance (e.g. relatively fast for the application domain). However, the majority of the proposed optimisation approaches for finding optimal composition plans, examine only the Quality of Service of each participated service in isolation without studying how the services are composed together within the composition. We argue that the consideration of multiple factors when searching for the optimal composition plans, such as which services are selected to participate in the composition, how these services are coordinated, communicate and interact within a composition, may improve the end-to-end quality of composite applications

Providing Mainstream Parser Generators with Modular Language Definition Support

The composition and reuse of existing textual languages is a frequently re-occurring problem. One possibility of composing textual languages lies on the level of parser specifications which are mainly based on context-free grammars and regular expressions. Unfortunately most mainstream parser generators provide proprietary specification languages and usually do not provide strong abstractions for reuse. New forms of parser generators do support modular language development, but they can often not be easily integrated with existing legacy applications. To support modular language development based on mainstream parser generators, in this paper we apply the Invasive Software Composition (ISC) paradigm to parser specification languages by using our Reuseware framework. Our approach is grounded on a platform independent metamodel and thus does not rely on a specific parser generator

Patterns in model engineering 2015 - A workshop summary

The Patterns in Model Engineering (PAME) workshop5 was held on 21 July 2015 as part of the Software Technologies: Applications and Foundations (STAF) conference, in L'Aquila, Italy. The workshop focused on identification, analysis and presentation of patterns across all aspects of modelling and Model-Driven Engineering (MDE), including patterns for modelling, metamodelling, transformation, and in constraints. The workshop featured three invited presentations by Jordi Cabot (ICREA, Spain), Daniel Varro (BME, Hungary) and Antonio Cicchetti (MDH, Sweden), five full papers, and a significant discussion and debate about the roles that patterns can play in modelling. This paper summarises the workshop discussion and highlights some of the key research challenges in the field

The COMQUAD Component Container Architecture and Contract Negotiation

Component-based applications require runtime support to be able to guarantee non-functional properties. This report proposes an architecture for a real-time-capable, component-based runtime environment, which allows to separate non-functional and functional concerns in component-based software development. The architecture is presented with particular focus on three key issues: the conceptual architecture, an approach including implementation issues for splitting the runtime environment into a real-time-capable and a real-time-incapable part, and details of contract negotiation. The latter includes selecting component implementations for instantiantion based on their non-functional properties

Model-driven performance analysis of rule-based domain specific visual models

Context: Domain-Specific Visual Languages (DSVLs) play a crucial role in Model-Driven Engineering (MDE). Most DSVLs already allow the specification of the structure and behavior of systems. However, there is also an increasing need to model, simulate and reason about their non-functional properties. In particular, QoS usage and management constraints (performance, reliability, etc.) are essential characteristics of any non-trivial system. Objective: Very few DSVLs currently offer support for modeling these kinds of properties. And those which do, tend to require skilled knowledge of specialized notations, which clashes with the intuitive nature of DSVLs. In this paper we present an alternative approach to specify QoS properties in a high-level and platform-independent manner. Method: We propose the use of special objects (observers) that can be added to the graphical specification of a system for describing and monitoring some of its non-functional properties. Results: Observers allow extending the global state of the system with the variables that the designer wants to analyze, being able to capture the performance properties of interest. A performance evaluation tool has also been developed as a proof of concept for the proposal. Conclusion: The results show how non-functional properties can be specified in DSVLs using observers, and how the performance of systems specified in this way can be evaluated in a flexible and effective way.Ministerio de Ciencia e Innovación TIN2008-031087Ministerio de Ciencia e Innovación TIN2011-2379