Abstract The profile of accessible design of digital games has increased rapidly in both research and practice. Whereas at one time accessibility was a niche area of interest, it is now a key feature promoted in commercial gaming. Typically, games achieve accessibility by offering a range of options, both in settings and gameplay, that players can customize to meet their individual needs and preferences. However, there is a distinct lack of systematic data regarding the accessibility options that players prefer, how options can be prioritized in design or how options can impact player experience. This paper presents a study that collects data about options preferred by players and uses it to expand and validate a design vocabulary for accessible design in games. Further, the results point to a need to prioritize particular types of options, specifically those relating to the player-feedback loop of games, before implementing options that modify the challenges encountered by players.

Abstract Semi-automated segmentation algorithms hold promise for improving extraction and identification of objects in images such as tumors in medical images of human tissue, counting plants or flowers for crop yield prediction or other tasks where object numbers and appearance vary from image to image. By blending markup from human annotators to algorithmic classifiers, the accuracy and reproducability of image segmentation can be raised to very high levels. At least, that is the promise of this approach, but the reality is less than clear. In this paper, we review the state-of-the-art in semi-automated image segmentation performance assessment and demonstrate it to be lacking the level of experimental rigour needed to ensure that claims about algorithm accuracy and reproducability can be considered valid. We follow this review with two experiments that vary the type of markup that annotators make on images, either points or strokes, in tightly controlled experimental conditions in order to investigate the effect that this one particular source of variation has on the accuracy of these types of systems. In both experiments, we found that accuracy substantially increases when participants use a stroke-based interaction. In light of these results, the validity of claims about algorithm performance are brought into sharp focus, and we reflect on the need for a far more control on variables for benchmarking the impact of annotators and their context on these types of systems.

Uncertainty has previously been identified as an important ingredient of engaging games. Design in games can create different levels of uncertainty in players that they can recognize and describe as being either attributable to external forces, such as chance or hidden information, or internal to their own understanding of what to do in relation to their own goals. While it appears that uncertainty can contribute both positive and negative play experiences, there is little work in trying to operationalize and measure this concept as a component of player experience. Reported in this article is an analysis of data from over 700 players using modern bi-factor analysis techniques resulting in a five factor psychometric scale which captures the broad feelings of players about uncertainty in games. Three of these specific factors appear to point toward a single generic factor of uncertainty that is internal to the players, one captures experiences relating to external uncertainty, with the final factor relating to player’s experience of exploring the game to resolve uncertainty. In order to further validate the scale, we conducted an experiment with a commercial puzzle game manipulating the duration of play with predicted outcomes on the different specific factors of the scale. Overall the scale shows promise with good statistical reliability and construct validity of the separate factors and so will be a useful tool for further investigating player experiences in digital games.

Abstract In research and practice into the accessibility of digital games, much of the work has focused on how to make games accessible to people with disabilities. With an increasing number of people with disabilities playing mainstream commercial games, it is important that we understand who they are and how they play in order to take a more user-centered approach as this field grows. We conducted a demographic survey of 154 players with disabilities and found that they play mainstream digital games using a variety of assistive technologies, use accessibility options such as key remapping and subtitles, and they identify themselves as gamers who play digital games as their primary hobby. This gives us a richer picture of players with disabilities and indicates that there are opportunities to begin to look at the accessible player experiences (APX) players have in games.

Smartphone technologies are now used to deploy audio and multimedia guides in cultural spaces, including historic churches. It is important to measure what effect the use of such technologies has on visitor experience of the cultural space and the usability and user experience of the guide. An “in the wild” study was conducted to investigate visitor experience in a historic church, with two versions of a multimedia iPhone Guide and with a traditional paper guide. The Church Experience Scale (CES) and the Multimedia Guide Scale (MMGS) were used to measure the experience of 59 visitors to Holy Trinity Church, Stratford-upon-Avon, known as Shakespeare’s church. A total of 40 visitors used an iPhone guide, 21 a free choice version and 19 a guided tour version, and 19 visitors used a paper guide. Results showed that participants with a smartphone guide had a significantly more positive visitor experience and spent significantly longer on their visit to the church. There was a significant correlation between length of visit and the Enjoyment, Intellectual Stimulation, and Curiosity factor of the CES, but further work is needed to understand the direction of causality in this relationship. The usability and user experience of the multimedia guide conditions did not differ from each other, but the results of the MMGS showed that both guides could be improved in terms of general usability and quality of interaction. Challenges of conducting a study “in the wild” of a smartphone app in a cultural space are discussed.

Archaeologists are currently producing huge numbers of digitized photographs to record and preserve artefact finds. These images are used to identify and categorize artefacts and reason about connections between artefacts and perform outreach to the public. However, finding specific types of images within collections remains a major challenge. Often, the metadata associated with images is sparse or is inconsistent. This makes keyword-based exploratory search difficult, leaving researchers to rely on serendipity and slowing down the research process. We present an image-based retrieval system that addresses this problem for biface artefacts. In order to identify artefact characteristics that need to be captured by image features, we conducted a contextual inquiry study with experts in bifaces. We then devised several descriptors for matching images of bifaces with similar artefacts. We evaluated the performance of these descriptors using measures that specifically look at the differences between the sets of images returned by the search system using different descriptors. Through this nuanced approach, we have provided a comprehensive analysis of the strengths and weaknesses of the different descriptors and identified implications for design in the search systems for archaeology.

Crowdsourcing has now been used in many areas, including to support people with disabilities. We explored the perceptions of students from two countries with very different cultures (Libya and the UK) of what would motivate them to participate in a crowdsourcing project (DescribeIT) to support their blind and partially sighted peers by describing images in digital learning resources. Students reported that they were interested to participate and particularly motivated by their sense of altruism and wanting to help others. The results also showed that British students reported a mix of intrinsic and extrinsic motivations, whereas for Libyan participants intrinsic motivations dominated over extrinsic. The results of this study will help us design the DescribeIT system to motivate students most effectively and should make developers of international crowdsourcing projects aware that motivations may differ between participants from different cultures.

Given the proliferation of devices like infusion pumps in hospitals, number entry and in particular number entry error is an emerging important concern in HCI. There are clearly design features that could greatly improve accuracy in entering numbers but the context of the task could also play an important role. In particular, the emotional state of a person is known to strongly influence their response to a difficult situation and hence the errors that they make. In this paper, we consider the impact of the emotional state of the user on the accuracy with which people enter numbers. Our experiment shows that participants who are in a more positive emotional state are more accurate. The effect is small but could be very important when considering the potentially highly-charged emotional contexts where many healthcare devices are used.

Numerous guidelines for making websites more accessible for older users have been proposed, but few provide evidence from such users for their recommendations This study investigated effects of line spacing and text justification on younger (24--31 years) and older (65--78 years) adults' performance and preferences in web reading tasks. The three levels of line spacing (single, 1.5, and double) and 2 types of text justification (left only and left-right) were studied. Neither variable had a significant effect on performance measures, although both younger and older adults preferred 1.5 or double spacing over single spacing. There were no significant differences in preferences for left versus left-right justification. These results suggest that contrary to common recommendations, 1.5 or double spacing should be recommended for all users, not only older users and that no recommendation is needed on text justification.

Expert evaluation methods, such as heuristic evaluation, are still popular in spite of numerous criticisms of their effectiveness. This paper investigates the usability problems found in the evaluation of six highly interactive websites by 30 users in a task-based evaluation and 14 experts using three different expert evaluation methods. A grounded theory approach was taken to categorize 935 usability problems from the evaluation. Four major categories emerged: Physical presentation, Content, Information Architecture and Interactivity. Each major category had between 5 and 16 sub-categories. The categories and sub-categories were then analysed for whether they were found by users only, experts only or both users and experts. This allowed us to develop an evidence-based set of 21 heuristics to assist in the development and evaluation of interactive websites.

This paper describes an empirical study of the problems encountered by 32 blind users on the Web. Task-based user evaluations were undertaken on 16 websites, yielding 1383 instances of user problems. The results showed that only 50.4% of the problems encountered by users were covered by Success Criteria in the Web Content Accessibility Guidelines 2.0 (WCAG 2.0). For user problems that were covered by WCAG 2.0, 16.7% of websites implemented techniques recommended in WCAG 2.0 but the techniques did not solve the problems. These results show that few developers are implementing the current version of WCAG, and even when the guidelines are implemented on websites there is little indication that people with disabilities will encounter fewer problems. The paper closes by discussing the implications of this study for future research and practice. In particular, it discusses the need to move away from a problem-based approach towards a design principle approach for web accessibility.

This is a report regarding the experiences of a requirements gathering and management effort for online services in education environments for people with disabilities. It details the challenges that were encountered in managing both the elicited data and the derived requirements from a diverse group of users, as well as the online wiki solution that was used to address them.

Abstract The use of digital document management and processing is increasing. Traditional workflows of paper forms are being replaced by electronic workflows of digital documents. These workflows often require multiple signatures to be added to the documents for authorization and/or integrity. We describe examples of digital workflows that illustrate problems with digital signatures: i.e. the use of digital signatures across entire documents results in signatures that can be unnecessarily invalidated by subsequent modification of the document. We propose the use of fragment signatures, which reduce unnecessary invalidation of signatures and enable greater concurrency in workflows. Our approach is document‐centric and does not use a centralized database. We report on an implementation that allows fragment signatures over document fragments as well as the attachment (or embedding) of other documents. This allows collaborative or cooperative editing to occur on parts of a document without disturbing unrelated signatures. We describe the lessons learned from our deployments and offer further ways to embed such signatures into other document types. Copyright © 2010 John Wiley & Sons, Ltd.

This paper presents the design of a new web browser, the Tree Trailblazer, which allows users to browse the web while maintaining a visual record of their exploration path, or trail, through the information space. This design enhances the backtracking aspects of web browsing over current designs by providing visual cues regarding the pages related to the page being viewed, providing users with an understanding of their position in the trail. This design also helps users blaze new trails off a page by allowing them to open previews of pages off of the currently viewed page. The scenario based design process that was used to construct the browser is discussed in conjunction with the initial prototype implementation. A formative user evaluation of this prototype showed this browser design to be very easy to learn and highly usable, with particular attention being paid to aspects of the tree visualization.