Open source communities have successfully developed a great deal of software although most computer users only use proprietary applications. The usability of open source software is often regarded as one reason for this limited distribution. In this paper we review the existing evidence of the usability of open source software and discuss how the characteristics of open source development influence usability. We describe how existing human-computer interaction techniques can be used to leverage distributed networked communities, of developers and users, to address issues of usability.

It is usually very hard, both for designers and users, to reason reliably about user interfaces. This article shows that ‘push button ’ and ‘point and click ’ user interfaces are algebraic structures. Users effectively do algebra when they interact, and therefore we can be precise about some important design issues and issues of usability. Matrix algebra, in particular, is useful for explicit calculation and for proof of various user interface properties. With matrix algebra, we are able to undertake with ease unusally thorough reviews of real user interfaces: this article examines a mobile phone, a handheld calculator and a digital multimeter as case studies, and draws general conclusions about the approach and its relevance to design.

Recent work is beginning to reveal the potential of numerical optimization as an approach to generating interfaces and displays. Optimization-based approaches can often allow a mix of independent goals and constraints to be blended in ways that would be difficult to describe algorithmically. While optimization-based techniques appear to offer several potential advantages, further research in this area is hampered by the lack of appropriate tools. This paper presents GADGET, an experimental toolkit to support optimization for interface and display generation. GADGET provides convenient abstractions of many optimization concepts. GADGET also provides mechanisms to help programmers quickly create optimizations, including an efficient lazy evaluation framework, a powerful and configurable optimization structure, and a library of reusable components. Together these facilities provide an appropriate tool to enable exploration of a new class of interface and display generation techniques.

This paper describes the concepts of TEA, a flexible tool that supports user tests by automating repetitive tasks and collecting data of user inputs and actions. TEA was specifically designed for...

In the context of document retrieval in the biomedical domain, this paper explores the complex relationship between the quality of initial query results and the overall utility of an interactive retrieval system. We demonstrate that a content-similarity browsing tool can compensate for poor retrieval results, and that the relationship between retrieval performance and overall utility is non-linear. Arguments are advanced with user simulations, which characterize the relevance of documents that a user might encounter with different browsing strategies. With broader implications to IR, this work provides a case study of how user simulations can be exploited as a formative tool for automatic utility evaluation. Simulation-based studies provide researchers with an additional evaluation tool to complement interactive and Cranfield-style experiments.

Open source projects are gradually incorporating usability methods into their development practices, but there are still many unmet needs. One particular need for nearly any open source project is data that describes its user base, including information indicating how the software is actually used in practice. This paper presents the concept of open instrumentation, or the augmentation of an open source application to openly collect and publicly disseminate rich application usage data. We demonstrate the concept of open instrumentation in ingimp, a version of the open source GNU Image Manipulation Program that has been modified to collect end-user usage data. ingimp automatically collects five types of data: The commands used, high-level user interface events, overall features of the user’s documents, summaries of the user’s general computing environment, and users ’ own descriptions of their planned tasks. In the spirit of open source software, all collected data are made available for anyone to download and analyze. This paper’s primary contributions lie in presenting the overall design of ingimp, with a particular focus on how the design addresses two prominent issues in open instrumentation: privacy and motivating use.

This paper presents the first field study of aimed movements in graphical user interfaces, designed to get better insight into pointing in the real (electronic) world and assess the validity of Fitts ’ law in the wild. We unobtrusively collected kinematic data from 24 users over several months, and segmented it into a table of 2 million movements. We show that Fitts ’ law is indeed robust for modeling pointing performance, provided that an adequate noise reduction process is applied. We introduce the length-distance index (LDI) to take into account the fact that many movements are not straight, and we introduce an extension of Fitts ’ law that includes an LDI term. We also show evidence of the effect of cognitive tasks in pause and click time, and the sensitivity of differences in performance, e.g., across input devices, to LDI. Altogether, these findings provide a firm ground to better assess the validity of results obtained in the laboratory.

Web site usability and accessibility continues to be a pressing problem. Hence, there are over 30 automated evaluation tools to help designers to improve their sites. Unfortunately, there is little evidence about whether these tools actually improve sites from both the designer's and the user's perspectives.

Computer-aided tools can be built to give support to different usability evaluation techniques, reducing some of their costs. These tools are complementary to existing fully automated ones, which are limited to the evaluation of external attributes. In this work, a generic model for questionnaire-based usability evaluation is described, along with the tool that implements it, which allows for fuzzy linguistic aggregation of opinions and provides support for results prediction based on similarity measures. Our tool is aimed at the exploitation of a growing database of evaluation facts with the help of various knowledge discovery and machine learning tools. Specifically, some preliminary applications of clustering and association mining techniques are described.

At one end of the spectrum, research in interactive content-based retrieval concentrates on machine learning methods for effective use of relevance feedback. On the other end, the information visualization community focuses on effective methods for conveying information to the user. What is lacking is research considering the information visualization and interactive retrieval as truly integrated parts of one content-based search system. In such an integrated system, there are many degrees of freedom like the similarity function, the number of images to display, the image size, different visualization modes, and possible feedback modes. To base the optimal values for all of those on user studies is unfeasible. We therefore develop search scenarios in which tasks and user actions are simulated. From there, the proposed scheme is optimized based on objective constraints and evaluation criteria. In such a manner, the degrees of freedom are reduced and the remaining degrees can be evaluated in user studies. In this article, we present a system that integrates advanced similarity based visualization with active learning. We have performed extensive experimentation on interactive category search with different image collections. The results using the proposed simulation scheme show that indeed the use of advanced visualization and active learning pays off in all of these datasets.