John McGinn

A Case Study Using a Methodological Approach to Developing User Interfaces for Elderly and Disabled People

In this paper, we present a case study on the development of interfaces for elderly and disabled users. The domain of the case study was situated in the home environment, where we focused on producing affordable technologies to enable users to interact with and to control home appliances. We have developed ambient user interfaces that are integrated in familiar home artefacts, such as televisions and digital picture frames. These interfaces are connected remotely to a home network and are adaptive to users’ expected increasing physical and cognitive needs. To support the development of the project, we created a novel methodology that is grounded in the ethical issues associated with a project of this nature. Our success with it has led to us presenting it here as a practical approach to developing user interfaces for a range of interactive applications, especially where there may be diverse user populations. This paper describes our journey through this project, how the methodology has been used throughout and the development of our user interfaces and their evaluation.

Real-time optimisation of access control lists for efficient Internet packet filtering

Abstract This paper considers an optimisation problem encountered in the implementation of traffic policies on network routers, namely the ordering of rules in an access control list to minimise or reduce processing time and hence packet latency. The problem is formulated as an objective function with constraints and shown to be NP-complete by translation to a known problem. Exact and heuristic solution methods are introduced, discussed and compared and computational results given. The emphasis throughout is on practical implementation of the optimisation process, that is within the tight constraints of a production network router seeking to reduce latency, on-line, in real-time but without the overhead of significant extra computation.

An argument for simple embedded ACL optimisation

The difficulty of efficiently reordering the rules in an Access Control List is considered and the essential optimisation problem formulated. The complexity of exact and sophisticated heuristics is noted along with their unsuitability for real time implementation embedded in the hardware of the network device. A simple alternative is proposed, in which a very limited rule reordering is considered following the processing of each packet. Simulation results are given from a range of traffic types. The method is shown to achieve savings that make its use worthwhile for lists longer than a given number of rules. This number is dependent on traffic characteristics but generally around 25 for typical network conditions.

The Easyline+ project: evaluation of a user interface developed to enhance independent living of elderly and disabled people

This paper reports the usability evaluation of interfaces developed to enable elderly and disabled people interact remotely with kitchen appliances in the home to enhance their independent living. A number of evaluation exercises were undertaken throughout the project’s development, including user-participative workshops and focus groups. This paper focuses on the summative usability evaluation exercise, which comprised a laboratory-based study in a simulated home environment, with a view to determining the appropriateness of employing this approach with potentially vulnerable participants. The study involved 27 participants interacting with the user interface. Their behaviour was observed and recorded, and their interaction with the system was analysed. They were also given a post-session questionnaire, where their opinions of the usability of the interface were solicited. The results of the usability testing were positive, and insight has been gained into how products of this nature can be further improved. The experience of conducting laboratory-based studies with vulnerable users was positive and led to propose in this paper a set of guidelines for future work in evaluating usability for work in this domain.

The use of interactive visual metaphors to enhance group discussions using mobile devices

In this paper, we consider the problems of group discussions and collaborative decision-making, where one or more of the participants are using restrictive interfaces such as mobile phones or PDAs. We suggest possible solutions to some of these problems and present MAVis (Mobile Argumentation Visualizer), a web-based interface built upon upon a balance-beam visual metaphor. We report on user experiences of interacting with the visual metaphor, and on the challenges of transferring this to a multi-user environment supporting mobile devices.