Aligning OCL with Domain-Specific Languages to Support Instance-Level Model Queries

The Object Constraint Language (OCL) provides a set of powerful facilities for navigating and querying models in the MOF metamodelling architecture. Currently, OCL queries can be expressed only in the context of MOF metamodels and UML models. This adds an additional burden to the development and use of Domain Specific Languages, which can also benefit from an instance-level querying mechanism. In an effort to address this issue, we report on ongoing work on defining a rigorous approach for aligning the OCL querying and navigation facilities with arbitrary Domain Specific Languages to support instance-level queries. We present a case-study that demonstrates the usefulness and practicality of this approach

Interface Contracts for Workflow+ Models: an Analysis of Uncertainty across Models

Workflow models are used to rigorously specify and reason about diverse types of processes. The Workflow+ (WF+) framework has been developed to support unified modelling of the control and data in processes that can be used to derive assurance cases that support certification. However, WF+ is limited in its support for precise contracts on workflow models, which can enable powerful forms of static analysis and reasoning. In this paper we propose a mechanism for adding interface contracts to WF+ models, which can thereafter be applied to tracing and reasoning about the uncertainty that arises when combining heterogeneous models. We specifically explore this in terms of design models and assurance case models. We argue that some of the key issues in managing some types of uncertainty can be partly addressed by use of interface contract

Saying Hello World with Epsilon - A Solution to the 2011 Instructive Case

Epsilon is an extensible platform of integrated and task-specific languages for model management. With solutions to the 2011 TTC Hello World case, this paper demonstrates some of the key features of the Epsilon Object Language (an extension and reworking of OCL), which is at the core of Epsilon. In addition, the paper introduces several of the task-specific languages provided by Epsilon including the Epsilon Generation Language (for model-to-text transformation), the Epsilon Validation Language (for model validation) and Epsilon Flock (for model migration).Comment: In Proceedings TTC 2011, arXiv:1111.440

The engineering of concurrent simulations of complex systems

Concurrent process-oriented programming is a natural medium for simulating complex systems, particularly systems where many simple components interact in an environment (which may itself be complex). There is little guidance for engineering complex systems simulation. In the context of simulation work to support immunological research, we explore relevant approaches to modelling, and draw on concepts from dependable and high-integrity systems engineering, including the emphasis on the need to validate all aspects of the simulation

Communicating Complex Systems

This paper outlines a new language and run-time technology offering formalised design and effiecient implementation for highly concuurent dynamic systems. It is based on a careful combination of ideas from Hoare’s CSP (giving compositional semantics, refinement and safety/liveness analysis) and Milners’s pi-calculus (giving dynamic network construction and mobility). We have been experimenting with systems developing as layered networks of self-organising neighbourhood-aware communicating processes, with no need for advanced planning or centralised control. The work reported is part of our TUNA (‘Theories Undepinning Nanite Assemblies’) project, in parnership with colleagues from the Universities of York and Surry, which is investigating formal approaches to the capture of safe emergent behaviour in highly complex systems. A particular study modelling artificial blood platelets is described. The software technology scales to millions of processes per processor and distributes over common multiprocssor clusters

Complex systems models: engineering simulations

As part of research towards the CoSMoS unified infrastructure for modelling and simulating complex systems, we review uses of definitional and descriptive models in natural science and computing, and existing integrated platforms. From these, we identify requirements for engineering models of complex systems, and consider how some of the requirements could be met, using state-of-the-art model management and a mobile, process-oriented computing paradigm

Accelerating Immunos 99

Immunos 99 is a classification algorithm based upon the principles of Artificial Immune Systems (AIS). AIS algorithms can provide alternatives to classical techniques such as decision trees for classification tasks. Immunos 99 provides one alternative however the algorithm and implementations have some room for performance improvement. This paper discusses improvements made to Immunos 99 and its reference implementation to improve runtime performance. The new algorithm/implementation results in an approximate 40% reduction in run time on test data. The paper closes with a proposal for an implementation of the Immunos 99 algorithm that is suitable for use on map/reduce clusters.</p