Managing change and time in dynamic workflow processes

Business environments have become exceedingly dynamic and competitive in recent times. This dynamism is manifested in the form of changing process requirements and time constraints. Workflow technology is currently one of the most promising fields of research in business process automation. However, workflow systems to date do not provide the flexibility necessary to support the dynamic nature of business processes. In this paper we primarily discuss the issues and challenges related to managing change and time in workflows representing dynamic business processes. We also present an analysis of workflow modifications and provide feasibility considerations for the automation of this process.

A formal framework for modelling and analysing mobile systems

This paper presents a formal framework for modelling and analysing mobile systems. The framework comprises a collection of models of the dominant design paradigms which are readily extended to incorporate details of particular technologies, i.e., programming languages and their run-time support, and applications. The modelling language is Object-Z, an extension of the well-known Z specification language with explicit support for object-oriented concepts. Its support for object orientation makes Object-Z particularly suited to our task. The system structuring techniques offered by object-orientation are well suited to modelling mobile systems. In addition, inheritance and polymorphism allow us to exploit commonalities in mobile systems by defining more complex models in terms of simpler ones.

Linear temporal logic and z refinement

Since Z, being a state-based language, describes a system in terms of its state and potential state changes, it is natural to want to describe properties of a specified system also in terms of its state. One means of doing this is to use Linear Temporal Logic (LTL) in which properties about the state of a system over time can be captured. This, however, raises the question of whether these properties are preserved under refinement. Refinement is observation preserving and the state of a specified system is regarded as internal and, hence, non-observable. In this paper, we investigate this issue by addressing the following questions. Given that a Z specification A is refined by a Z specification C, and that P is a temporal logic property which holds for A, what temporal logic property Q can we deduce holds for C? Furthermore, under what circumstances does the property Q preserve the intended meaning of the property P? The paper answers these questions for LTL, but the approach could also be applied to other temporal logics over states such as CTL and the mgr-calculus.

Using integrated metamodeling to define OO design patterns with object-z and UML

Three important goals in describing software design patterns are: generality, precision, and understandability. To address these goals, this paper presents an integrated approach to specifying patterns using Object-Z and UML. To achieve the generality goal, we adopt a role-based metamodeling approach to define patterns. With this approach, each pattern is defined as a pattern role model. To achieve precision, we formalize role concepts using Object-Z (a role metamodel) and use these concepts to define patterns (pattern role models). To achieve understandability, we represent the role metamodel and pattern role models visually using UML. Our pattern role models provide a precise basis for pattern-based model transformations or refactoring approaches.

An approach to specifying software frameworks

A framework is a reusable design that requires software components to function. To instantiate a framework, a software engineer must provide the software components required by the framework. To do this effectively, the framework-component interfaces must be specified so the software engineer knows what assumptions the framework makes about the components, and so the components can be verified against these assumptions. This paper presents an approach to specifying software frameworks. The approach involves the specification of the framework’s syntax, semantics, and the interfaces between the framework and its components. The approach is demonstrated with a simple case study.

A case study in specification and implementation testing

Achieving consistency between a specification and its implementation is an important part of software development In previous work, we have presented a method and tool support for testing a formal specification using animation and then verifying an implementation of that specification. The method is based on a testgraph, which provides a partial model of the application under test. The testgraph is used in combination with an animator to generate test sequences for testing the formal specification. The same testgraph is used during testing to execute those same sequences on the implementation and to ensure that the implementation conforms to the specification. So far, the method and its tool support have been applied to software components that can be accessed through an application programmer interface (API). In this paper, we use an industrially-based case study to discuss the problems associated with applying the method to a software system with a graphical user interface (GUI). In particular, the lack of a standardised interface, as well as controllability and observability problems, make it difficult to automate the testing of the implementation. The method can still be applied, but the amount of testing that can be carried on the implementation is limited by the manual effort involved.

Testing java interrupts and timed waits

Testing concurrent software is difficult due to problems with inherent nondeterminism. In previous work, we have presented a method and tool support for the testing of concurrent Java components. In this paper, we extend that work by presenting and discussing techniques for testing Java thread interrupts and timed waits. Testing thread interrupts is important because every Java component that calls wait must have code dealing with these interrupts. For a component that uses interrupts and timed waits to provide its basic functionality, the ability to test these features is clearly even more important. We discuss the application of the techniques and tool support to one such component, which is a nontrivial implementation of the readers-writers problem.

Bridging technical and HCI research: Creating usable ubiquitous computing

This paper describes methods used to support collaboration and communication between practitioners, designers and engineers when designing ubiquitous computing systems. We tested methods such as “Wizard of Oz” and design games in a real domain, the dental surgery, in an attempt to create a system that is: affordable; minimally disruptive of the natural flow of work; and improves human-computer interaction. In doing so we found that such activities allowed the practitioners to be on a ‘level playing ground’ with designers and engineers. The findings we present suggest that dentists are willing to engage in detailed exploration and constructive critique of technical design possibilities if the design ideas and prototypes are presented in the context of their work practice and are of a resolution and relevance that allow them to jointly explore and question with the design time. This paper is an extension of a short paper submitted to the Participatory Design Conference, 2004.

Interference between propagating changes and its effect on system failure

Computer-based, socio-technical systems projects are frequently failures. In particular, computer-based information systems often fail to live up to their promise. Part of the problem lies in the uncertainty of the effect of combining the subsystems that comprise the complete system; i.e. the system's emergent behaviour cannot be predicted from a knowledge of the subsystems. This paper suggests uncertainty management is a fundamental unifying concept in analysis and design of complex systems and goes on to indicate that this is due to the co-evolutionary nature of the requirements and implementation of socio-technical systems. The paper shows a model of the propagation of a system change that indicates that the introduction of two or more changes over time can cause chaotic emergent behaviour.