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

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

Towards Automatic Generation of Evolution Rules for Model-Driven Optimisation

Over recent years, optimisation and evolutionary search have seen substantial interest in the MDE research community. Many of these techniques require the specification of an optimisation problem to include a set of model transformations for deriving new solution candidates from existing ones. For some problems—for example, planning problems, where the domain only allows specific actions to be taken—this is an appropriate form of problem specification. However, for many optimisation problems there is no such domain constraint. In these cases providing the transformation rules over-specifies the problem. The choice of rules has a substantial impact on the efficiency of the search, and may even cause the search to get stuck in local optima.In this paper, we propose a new approach to specifying optimisation problems in an MDE context without the need to explicitly specify evolution rules. Instead, we demonstrate how these rules can be automatically generated from a problem description that consists of a meta-model for problems and candidate solutions, a list of meta-classes, instances of which describe potential solutions, a set of additional multiplicity constraints to be satisfied by candidate solutions, and a number of objective functions. We show that rules generated in this way lead to optimisation runs that are at least as efficient as those using hand-written rules

Trustworthy Agent-Based Simulation: The Case for Domain-Specific Modelling Languages

Simulation is a key tool for researching complex system behaviour. Agent-based simulation has been applied across domains, such as biology, health, economics and urban sciences. However, engineering robust, efficient, maintainable, and reliable agent-based simulations is challenging. We present a vision for engineering agent simulations comprising a family of domain-specific modelling languages (DSMLs) that integrates core software engineering, validation and simulation experimentation. We relate the vision to examples of principled simulation, to show how the DSMLs would improve robustness, efficiency, and maintainability of simulations. Focusing on how to demonstrate the fitness for purpose of a simulator, the envisaged approach supports bi-directional transparency and traceability between the original domain understanding to the implementation, interpretation of results and evaluation of hypotheses

Scheduling Real-Time Components Using Jitter-Constrained Streams.

Selected for publication in JOT as one of the best papers of AQuSerM'0

Automatic Generation of Atomic Consistency Preserving Search Operators for Search-Based Model Engineering

Recently there has been increased interest in combining the fields of Model-Driven Engineering (MDE) and Search-Based Software Engineering (SBSE). Such approaches use meta-heuristic search guided by search operators (model mutators and sometimes breeders) implemented as model transformations. The design of these operators can substantially impact the effectiveness and efficiency of the metaheuristic search. Currently, designing search operators is left to the person specifying the optimisation problem. However, developingconsistent and efficient search-operator rules requires not only domain expertise but also in-depth knowledge about optimisation, which makes the use of model-based meta-heuristic search challenging and expensive. In this paper, we propose a generalised approach to automatically generate atomic consistency preserving search operators (aCPSOs) for a given optimisation problem. This reduces the effort required to specify an optimisation problem and shields optimisation users from the complexity of implementing efficient meta-heuristic search mutation operators. We evaluate our approach with a set of case studies, and show that the automatically generated rules are comparable to, and in some cases better than, manually created rules at guiding evolutionary search towards near-optimal solutions