Research—Andrew Berry

Business contracts play a central role in governing commercial interactions between organizations. It is increasingly recognized that business contract conditions need to be closely linked to internal and external business processes, both to reduce the risk of contract violations and to ensure compliance with legislative regimes. Recent research has proposed contract languages allowing the specification of obligations, permissions and prohibitions in business contracts. Business processes that cross-organizational boundaries can be specified in choreography and coordination languages but these do not provide appropriate abstractions for contract constraints. In this paper, we examine the transformation of contract constraints in a business contract language into expressions in a choreography language. An example cross-organizational process is presented, along with a specification of the process in a choreography language and a specification of a set of contract conditions for the process in a business contract language. The contract terms are then translated into choreography expressions that govern the process to ensure compliance. Subsequent discussion explores a number of business and technology issues related to the results. We conclude that cross-organizational business processes can be monitored and enforced according to business contract specifications through the transformation of a contract definition to constraints on process behavior.

In this paper we outline a semantic model for open distributed systems which provides a foundation for a corresponding architecture description language. This semantic model is based on architecture models reported in [2][5], with a number of refinements to support abstraction and composition. The model is specifically designed to describe open distributed systems independent of implementation details such as communication protocols and middleware systems. The modelling concepts in the semantic model are: object (a model of an entity), event (a unit of interaction between an object and its environment), event relationship (a specification of behaviour defining the relationships amongst a set of events), interface (an abstraction of an object’s interaction with its environment) and binding (a context for interaction between objects). The binding concept is particularly important because it can describe any kind of interaction in an open distributed system, ranging from remote procedure calls and multicast to more complex,enterprise interactions. Special attention is given to the problem of composition and abstraction of events and behaviour in the model. This is needed to reflect the reuse, evolution and interworking requirements of open distributed systems. Our approach allows for the effective modelling of asynchrony,concurrency and complex flows of information in open distributed systems.

Maintenance of causality information in distributed systems has previously been implemented in the communications infrastructure with the focus on providing reliability and availability for distributed services. While this approach has a number of advantages, moving causality information up into the view and control of the application programmer is useful, and in some cases, preferable. In an experiment at the University of Queensland, libraries to support application-level maintenance of causality information have been implemented. The libraries allow the collection and use of causality information under programmer control, supplying a basis for making causal dependency information available for application management and troubleshooting. The libraries are also unique in supporting existing distributed systems based on the remote procedure call paradigm. This paper describes the underlying theory of causality, and the design and implementation of the libraries. An event reporting service example is used to motivate the approach, and a number of previously unresolved practical problems are addressed in the design process.

Healthcare organizations are increasingly using information technology to ensure patient safety, increase effectiveness and improve efficiency of healthcare delivery. While the use of health information technology (HIT) has realized many improvements, it has also introduced new failure modes arising from data quality and IT system usability issues. This paper presents an approach towards addressing these failure modes by applying real-time analytics to existing streams of clinical messages exchanged by HIT systems. We use complex event processing provided by the EventSwarm software framework to monitor data quality in such systems through intercepting messages and applying rules reflecting the syndromic surveillance model proposed in [4]. We believe this is the first work reporting on the real-time application of syndromic surveillance rules to legacy clinical data streams. Our design and implementation demonstrates the feasibility of this approach and highlights benefits obtained through improved operational quality of HIT systems, notably better patient safety, reduced risks in healthcare delivery and potentially reduced costs.

Coordination languages have recently been attracting significant attention as a means of programming parallel and distributed systems. The approach of separating coordination from computation is particularly attractive in distributed systems because there are a wide range of possible interaction, quality and reliability semantics that are either hidden or ignored by traditional infrastructures based on remote procedure call. Introducing an explicit, programmable model for the distributed infrastructure makes these semantics visible and tractable, without requiring substantial changes in distributed components. This paper presents Finesse, a language for describing the interaction of components in open distributed systems, and demonstrates its power through a number of examples.

Distributed software is traditionally built by connecting a set of software components using a communications abstraction. The interaction semantics provided by the abstraction is predominantly static: any programming of behavior occurs in the components or in local wrappers around those components. While autonomous behavior can be programmed over these abstractions, there is increasing awareness that static interaction models are not sufficient to capture the semantic diversity found in dynamic, evolving distributed systems. This paper presents an asynchronous, distributed and executable semantic model suitable for implementing programmable connector objects. Programs described using the semantic model can be jointly executed by a set of autonomous, distributed participants with no explicit synchronization of execution state. By removing the requirement for explicit synchronization, participants can execute independently with no requirement for centralized mediation, and the asynchrony of the model implicitly allows for potentially high latencies in distributed environments like the Internet. This combination of properties makes the model ideal for E-commerce applications.