Publications

Harrison M, Masci P, Campos JC, Curzon P.  In Press.  The specification and analysis of use properties of a nuclear control system. Formal Methods in Human Computer Interaction. Abstract

The chapter explores a layered approach to the analysis of the Nuclear Power Plant Control System described in Chapter 4. A model is specified to allow the analysis of use-centred properties based on generic templates. User interface properties include: the visibility of state attributes, the clarity of the mode structure and the ease with which an action can be recovered from. Property templates are used as heuristics to ease the construction of requirements for the control system interface.

Campos JC, Saraiva JA, Silva CE, Silva JC.  2012.  GUIsurfer: A Reverse Engineering Framework for User Interface Software. Reverse Engineering - Recent Advances and Applications. :31-54. Abstract

In the context of developing tool support to the automated analysis of interactive systems implementations, this chapter proposal aims to investigate the applicability of reverse engineering approaches to the derivation of user interfaces behavioural models. The ultimate goal is that these models might be used to reason about the quality of the system, both from an usability and an implementation perspective, as well as being used to help systems maintenance, evolution and redesign.

Harrison M, Campos JC, Loer K.  2008.  Formal analysis of interactive systems: opportunities and weaknesses. Research Methods in Human Computer Interaction. :88-111. Abstract

Although formal techniques are not widely used in the analysis of interactive systems there are reasons why an appropriate set of tools, suitably designed to be usable by system engineers, could be of value in the portfolio of techniques used to assess interactive systems. This chapter describes the role of formal techniques in modelling and analysing interactive systems, discusses unfulfilled opportunities and speculates about the removal of barriers to their use. It also presents the opportunities that a clear expression of the problem and systematic analysis techniques may afford.

Harrison M, Campos JC, Doherty G, Loer K.  2008.  Connecting rigorous system analysis to experience centred design. Maturing Usability: Quality in Software, Interaction and Value. :56-74. Abstract

The chapter explores the role that formal modelling may play in aiding the visualisation and implementation of usability with a particular emphasis on experience requirements in an ambient and mobile system. Mechanisms for requirements elicitation and evaluation are discussed, as well as the role of scenarios and their limitations in capturing experience requirements. The chapter then discusses the role of formal modelling by revisiting an analysis based on an exploration of traditional usability requirements before moving on to consider requirements more appropriate to a built environment. The role of modelling within the development process is re-examined by looking at how models may incorporate knowledge relating to user experience and how the results of the analysis of such models may be exploited by human factors and domain experts in their consideration Ambient and mobile systems are often used to bring information and services.

Campos JC, Harrison M.  2006.  Automated deduction and usability reasoning. Encyclopedia of Human-Computer Interaction. :45-54. Abstract

Reasoning about the usability of a given interactive system's design is a difficult task. However it is one task that must be performed if downstream costs with extensive redesign are to be avoided. Traditional usability testing alone cannot avoid these costs since it too often is performed late in development life cycle. In recent years approaches have been put forward that attempt to reason about the usability of a design from early in development. Mainstream approaches are based on some kind of (more or less structured) inspection of a design by usability experts. This type of approach breaks down for systems with large and complex user interfaces, and again extensive testing is required. In an attempt to deal with these issues there have been attempts to apply software engineering reasoning tools to the development of interactive systems. The article reviews this work and puts forward some ideas for the future.

Fernandes A, Pereira JR, Campos JC.  2006.  Accessibility and Visually Impaired Users. Enterprise Information Systems VI. Abstract

Internet accessibility for the visually impaired community is still an open issue. Guidelines have been issued by the W3C consortium to help web designers to improve web site accessibility. However several studies show that a significant percentage of web page creators are still ignoring the proposed guidelines. Several tools are now available, general purpose, or web specific, to help visually impaired readers. But is reading a web page enough? Regular sighted users are able to scan a web page for a particular piece of information at high speeds. Shouldn't visually impaired readers have the same chance? This paper discusses some features already implemented to improve accessibility and presents a user feedback report regarding the AudioBrowser, a talking browser. Based on the user feedback the paper also suggests some avenues for future work in order to make talking browsers and screen readers compatible.

Couto R, Ribeiro AN, Campos JC.  2016.  Validating an approach to formalize use cases with ontologies. Proceedings of the 13th International Workshop on Formal Engineering Approaches to Software Components and Architectures. 205:1-15. Abstract1603.08632v1.pdf

Use case driven development methodologies put use cases at the center of the software development process. However, in order to support automated development and analysis, use cases need to be appropriately formalized. This will also help guarantee consistency between requirements specifications and the developed solutions. Formal methods tend to suffer from take up issues, as they are usually hard to accept by industry. In this context, it is relevant not only to produce languages and approaches to support formalization, but also to perform their validation. In previous works we have developed an approach to formalize use cases resorting to ontologies. In this paper we present the validation of one such approach. Through a three stage study, we evaluate the acceptance of the language and supporting tool. The first stage focusses on the acceptance of the process and language, the second on the support the tool provides to the process, and finally the third one on the tool's usability aspects. Results show test subjects found the approach feasible and useful and the tool easy to use.

Campos JC, Fayollas C, Martinie C, Navarre D, Palanque P, Pinto M.  2016.  Systematic Automation of Scenario-Based Testing of User Interfaces. In Proceedings of the 8th ACM SIGCHI Symposium on Engineering Interactive Computing Systems, pages 138-148. Abstractfp0148-paper.pdf

Ensuring the effectiveness factor of usability consists in ensuring that the application allows users to reach their goals and perform their tasks. One of the few means for reaching this goal relies on task analysis and proving the compatibility between the interactive application and its task models. Synergistic execution enables the validation of a system against its task model by co-executing the system and the task model and comparing the behavior of the system against what is prescribed in the model. This allows a tester to explore scenarios in order to detect deviations between the two behaviors. Manual exploration of scenarios does not guarantee a good coverage of the analysis. To address this, we resort to model-based testing (MBT) techniques to automatically generate scenarios for automated synergistic execution. To achieve this, we generate, from the task model, scenarios to be co-executed over the task model and the system. During this generation step we explore the possibility of including considerations about user error in the analysis. The automation of the execution of the scenarios closes the process. We illustrate the approach with an example.

Harrison M, Campos JC, Ruksenas R, Curzon P.  2016.  Modelling information resources and their salience in medical device design. In Proceedings of the 8th ACM SIGCHI Symposium on Engineering Interactive Computing Systems, pages 194-203. Abstractocbeics16pub.pdf

The paper describes a model that includes an explicit description of the information resources that are assumed to guide use, enabling a focus on properties of "plausible interactions". The information resources supported by an interactive system should be designed to encourage the correct use of the system. These resources signpost a user's interaction, helping to achieve desired goals. Analysing assumptions about information resource support is particularly relevant when a system is safety critical that is when interaction failure consequences could be dangerous, or walk-up-and-use where interaction failure may lead to reluctance to use with expensive consequences. The paper shows that expressing these resource constraints still provides a wider set of behaviours than would occur in practice. A resource may be more or less salient at a particular stage of the interaction and as a result potentially overlooked. For example, the resource may be accessible but not used because it does not seem relevant to the current goal. The paper describes how the resource framework can be augmented with additional information about the salience of the assumed resources. A medical device that is in common use in many hospitals is used as illustration.

Abade T, Campos JC, Moreira R, Silva CC, Silva JL.  2015.  Immersiveness of Ubiquitous Computing Environments Prototypes: A case study. Lecture Notes in Computer Science. 9189 Abstract15-dapi-abadecmss-sarch.pdf

The development of ubiquitous computing (ubicomp) environments raises several challenges in terms of their evaluation. Ubicomp virtual reality prototyping tools enable users to experience the system to be developed and are of great help to face those challenges, as they support developers in assessing the consequences of a design decision in the early phases of development. Given the situated nature of ubicomp environments, a particular issue to consider is the level of realism provided by the prototypes. This work presents a case study where two ubicomp prototypes, featuring different levels of immersion (desktop-based versus CAVE-based), were developed and compared. The goal was to determine the cost/benefits relation of both solutions, which provided better user experience results, and whether or not simpler solutions provide the same user experience results as more elaborate one.

Lamas J, Silva CC, Silva M, Mouta S, Campos JC, Santos J.  2015.  Measuring end-to-end delay in real-time auralisation systems. Euronoise – 10th European Congress and Exposition on Noise Control Engineering Abstractend2enddelay_euronoise2015.pdf

One of the major challenges in the development of an immersive system is handling the delay between the tracking of the user’s head position and the updated projection of a 3D image or auralised sound, also called end-to-end delay. Excessive end-to-end delay can result in the general decrement of the “feeling of presence”, the occurrence of motion sickness and poor performance in perception-action tasks. These latencies must be known in order to provide insights on the technological (hardware/software optimization) or psychophysical (recalibration sessions) strategies to deal with them. Our goal was to develop a new measurement method of end-to-end delay that is both precise and easily replicated. We used a Head and Torso simulator (HATS) as an auditory signal sensor, a fast response photo-sensor to detect a visual stimulus response from a Motion Capture System, and a voltage input trigger as real-time event. The HATS was mounted in a turntable which allowed us to precisely change the 3D sound relative to the head position. When the virtual sound source was at 90º azimuth, the correspondent HRTF would set all the intensity values to zero, at the same time a trigger would register the real-time event of turning the HATS 90º azimuth. Furthermore, with the HATS turned 90º to the left, the motion capture marker visualization would fell exactly in the photo-sensor receptor. This method allowed us to precisely measure the delay from tracking to displaying. Moreover, our results show that the method of tracking, its tracking frequency, and the rendering of the sound reflections are the main predictors of end-to-end delay.

Almeida D, Campos JC, Saraiva JA, Silva JC.  2015.  Towards a catalog of usability smells. SAC - Proceedings of the 30th Annual ACM Symposium on Applied Computing. Abstractsac2015_1.pdf

This paper presents a catalog of smells in the context of interactive applications. These so-called usability smells are indicators of poor design on an application's user interface, with the potential to hinder not only its usability but also its maintenance and evolution. To eliminate such usability smells we discuss a set of program/usability refactorings. In order to validate the presented usability smells catalog, and the associated refactorings, we present a preliminary empirical study with software developers in the context of a real open source hospital management application. Moreover, a tool that computes graphical user interface behavior models, giving the applications' source code, is used to automatically detect usability smells at the model level.

Machado M, Campos JC, Couto R.  2015.  MODUS: uma metodologia de prototipagem de interfaces baseada em modelos. Inforum 2015: Atas do 7º Simpósio Nacional de Informática. :17-32.inforum-2015.pdf
Harrison M, Campos J, Masci P, Curzon P.  2015.  Templates as heuristics for proving properties of medical devices. 5th EAI International Conference on Wireless Mobile Communication and Healthcare - "Transforming healthcare through innovations in mobile and wireless technologies". antennatemplatesv5-final.pdf
Campos JC, Silva JL, Harrison M.  2015.  Supporting the Design of an Ambient Assisted Living System Using Virtual Reality Prototypes. Ambient Assisted Living. ICT-based Solutions in Real Life Situations. 9455:49-61.authorsversion.pdf