Jasper Lindenberg

An online lifestyle diary with a persuasive computer assistant providing feedback on self-management

In accordance with the global trend, in The Netherlands approximately 45% of the population is overweight. Existing studies show that patient self-management can reduce these figures, but medical non-adherence is a persistent problem. eHealth can potentially increase adherence to self-management. Consequently, we designed a persuasive computer assistant and evaluated its influence on self-management, i.e., the use of an online lifestyle diary called DieetInzicht.nl. The assistant is represented by an animated iCat, which shows different facial expressions and provides cooperative feedback following principles from the motivational interviewing method. We conducted a randomized controlled trial with 118 overweight people over a period of four weeks and studied the difference between diary use with and without computer assistant feedback. Results show that the computer assistant contributed to filling in the diary more frequently, reduced the decline in motivation to perform self-management, lowered the (reported) BMI, and improved the ease of use. Furthermore, diary use increased knowledge of maintaining a healthy lifestyle. Finally, personal characteristics, i.e., locus of control, vocabulary, computer experience, age, gender, education level and initial BMI, explained the variance in the diary use and its outcome. Of the 118 participants 35 filled in the closing survey, covering motivation, BMI, lifestyle knowledge and ease of use, which implies that the findings based on these results are mainly representative for motivated participants. In general, this study shows that the Dieetinzicht eHealth service, including a personal computer assistant, is likely to support motivated overweight people and lifestyle related diseases to get a better insight in and adhere to their self-management.

Usability trade-offs for adaptive user interfaces: ease of use and learnability

An analysis of context-aware user interfaces shows that adaptation mechanisms have a cost-benefit trade-off for usability. Unpredictable autonomous interface adaptations can easily reduce a systems usability. To reduce this negative effect of adaptive behaviour, we have attempted to help users building adequate mental models of such systems. A user support concept was developed and applied to a context-aware mobile device with an adaptive user interface. The approach was evaluated with users and as expected, the user support improved ease of use, but unexpectedly it reduced learnability. This shows that an increase of ease of use can be realised without actually improving the users mental model of adaptive systems.

Improving service matching and selection in ubiquitous computing environments: a user study

In large ubiquitous computing environments it is hard for users to identify and activate the electronic services that match their needs. This user study compares the newly developed service matcher system with a conventional system for identifying and selecting appropriate services. The study addresses human factors issues such as usability, trust and service awareness. With the conventional system users have to browse a hierarchical list of currently available services and activate the service that they think satisfies their current needs. With the service matcher users just enter their current need using natural language, after which a wizard, emulating an existing service matcher algorithm, searches for and activates a matching service based on the given need and the users’ location and gaze direction. This study shows that with the hierarchical list, only 66% of the tasks are solved correctly, and females score significantly worse than males. With the service matcher, the performance increases significantly to 84% correctly performed tasks and the gender difference disappears.

Effects of mobile map orientation and tactile feedback on navigation speed and situation awareness

Mobile information systems aid first responders in their tasks. Support is often based on mobile maps. People have different preferences for map orientations (heading-up or north-up), but map orientations also have different advantages and disadvantages. In general north-up maps are good for building up situation awareness and heading-up maps are better for navigational tasks. Because of heavily loaded visual modalities, we expect that tactile waypoint information can enhance navigation speed and situation awareness. In this paper we describe an experiment conducted in a synthetic task environment, in which we examined the effect of heading-up and north-up displays on search and rescue performance of first responders, and if adding the tactile display improves performance.

Support concepts for Web navigation: a cognitive engineering approach

Current Network User Interfaces (NUIs) provide entrances to an enormous amount of Web-based services, bringing about new use problems such as laborious and unsuccessful navigation. Such problems are generally more severe for users with regression of cognitive functions (e.g. for some elderly). This paper identifies four fundamental cognitive determinants of navigation performance that may explain these problems: situation awareness, spatial ability, task-set switching and user control of support. Based on an analysis of these demands and current support functions for navigation, three “refined” support concepts were developed: categorising landmarks, history map and navigation assistant. Via the specification of humancomputer co-operative processes and scenarios, the concepts were implemented for two rather different web-based services. The present paper provides an example implementation of the navigation assistant. The results of the study will feed into a cognitive engineering method for the design of NUIs.

Users want simple control over device selection

When users want to combine various resources in an ambient intelligent environment in an ad hoc manner, they need to be able to identify and select these resources. We conducted an experiment to study various user interaction styles for combining input and output devices in an ambient intelligent environment. The results show that the test subjects prefer to press a designated button on a device to select it. They least prefer an automatic selection. The main conclusion is that our subjects are willing to spend a bit of time and effort in order to gain control over their environment. This supports the claim that users acting in ambient intelligent environments should always be kept in the loop; systems should take care not to alienate their users when making decisions for them.

Human-agent service matching using natural language queries: system test and training

Smart environments, ambient intelligence and intelligent agents leave the user lost between large amounts of services. Ad-hoc networks, mobile agents and mobile devices make the set of available services dynamic over time and space, increasing the user’s problems to find the service he needs. Earlier, we presented a ServiceMatcher that can find the agent best fitting to the user’s natural language request. This paper presents performance results of the ServiceMatcher. The test queries come from human users in a realistic scenario (see our other paper in this issue). With a short training of the agent vocabularies, over 80% correct service matches are found.

SuperAssist: A User-Assistant Collaborative Environment for the supervision of medical instrument use at home

With the rise of Transmural care, patients increasingly use medical instruments at home. Maintenance and troubleshooting greatly determines the safety and accuracy of these instruments. For the supervision of these complex tasks, we developed a user-assistant collaborative environment (U-ACE). We designed three types of personal virtual assistants that vary in dialogue style and level of autonomy. According to the scenario-based design method, we did a laboratory experiment and evaluated the influence of the different assistant types on the usability of the U-ACE. Additionally, we examined if considering personal characteristics can help better gear the assistant to the users needs. Results showed that a cooperative assistant focusing on interaction and guiding the user through the required steps, was best suited and was declared the most preferred. Collaboration with an autonomous assistant that acts autonomously led to the most efficient performance. Furthermore, personal characteristics explained variance in the experienced usability. It is recommended that, while using the U-ACE, the users select their own assistant type depending on context and personal characteristics

A computer assistant for remote collaborative troubleshooting of domestic medical instruments

Patients suffering from chronic illness, such as diabetes, use various domestic instruments as part of their self-care. For older adults, there is a need for assistance to use the instruments adequately and to solve technical failures. Following the eHealth concept, we designed a computer assistant for an older adult and a technical specialist, which supports remote collaborative troubleshooting which tailors the feedback to the userspsila needs. We evaluated two feedback styles, i.e., cooperative and directive, in the TNO experience lab, with older and younger adults playing the role of patient and technical specialist, respectively, in ldquofailure scenariosrdquo. Results show that most effective troubleshooting occurs with teams consisting of a older patient receiving cooperative feedback and a younger technical specialist receiving directive feedback. In addition, the patient experienced more effort than the technical specialist. Further, different personal characteristics had moderating effects on the evaluation of the feedback styles. Our study concluded that different user groups require different feedback styles and that computer assistance for remote collaborative troubleshooting will be optimal when this feedback is personalized.