Scenarios have been advocated as a means of improving requirements engineering yet few methods or tools exist to support scenario based RE. The paper reports a method and software assistant tool for scenario-based RE that integrates with use case approaches to object oriented development. The method and operation of the tool are illustrated with a financial system case study. Scenarios are used to represent paths of possible behaviour through a use case and these are investigated to elaborate requirements. The method commences by acquisition and modelling of a use case. The use case is then compared with a library of abstract models that represent different application classes. Each model is associated with a set of generic requirements for its class, hence, by identifying the class(es) to which the use case belongs, generic requirements can be reused. Scenario paths are automatically generated from use cases, then exception types are applied to normal event sequences to suggest possib...

A method for scenario-based requirements engineering is described. The method uses two types of scenario: structure models of " the system context and scripts of system usage. A modelling language is reported for describing scenarios, and heuristics are given to crosscheck dependencies between scenario models and the requirements specification. Heuristics are grouped into several anah,tic treatments that investigate correspondences between users' goals and system fimctions; input events and system processes to deal with them: system output and its destination in the scenario model, and acceptability anah,sis of system output for different stakehoMetw. The method is i/htstrated with a case study taken from the London Ambulance Service report. The prospects for scenario-based requirements engineering and related work are discussed.

We describe an approach to user interface design based on ideas from social science, narratology (the theory of stories), cognitive science, and a new area called algebraic semiotics. Social analysis helps to identify certain roles for users with their associated requirements, and suggests ways to make proofs more understandable, while algebraic semiotics, which combines semiotics with algebraic specification, provides rigorous theories for interface functionality and for a certain technical notion of quality. We apply these techniques to designing user interfaces for a distributed cooperative theorem proving system, whose main component is a website generation and proof assistance tool called Kumo. This interface integrates formal proving, proof browsing, animation, informal explanation, and online background tutorials, drawing on a richer than usual notion of proof. Experience with using the interface is reported, and some conclusions are drawn.

This paper reports a method of assessing the implications for human error on system requirements, a topic not usually considered during requirements engineering (RE). In our previous work, we proposed a taxonomy of influencing factors that might contribute to human error. This paper takes the taxonomy and elaborates it to suggest generic requirements to deal with problems in different layers of the taxonomy. Components of the taxonomy are combined into a causal model for error, represented as a Bayesian Belief Net (BBN). BBNs model the error influences arising from user knowledge, ability, and the task environment. These are combined with factors describing the complexity of action and user interface quality in scenarios of projected system usage. The BBN model predicts probabilities of slips and mistakes. These are assessed according to action types in the scenario to suggest generic requirements to prevent the error or to deal with its consequences. The method is illustrated by a ser...

One of the most important gaps in road safety management practises is the lack of mature methods for estimating reliability. Road safety performance assessment systems have been developed; however, these provide only historical or retrospective analyses. Effective safety management requires a prospective viewpoint. The main goal of this research is to assist in reducing accident rates in Cyprus by providing ample time to the authorities to react to high risk situations through a safety prediction early warning system. This ultimately will prevent accidents from occurring which subsequently could save lives. Traditional approaches focuses solidly on empirical data concerning road network dynamic properties, despite the fact that the most vulnerable component of the system is the human element. This paper described the integration of agent-based simulation with Bayesian Belief Networks (BBN) for improved quantification of accident probability. The BBN is developed using multidisciplinary influences. 1