Christoph Evers

The user in the loop: Enabling user participation for self-adaptive applications

Future computing systems must adjust to the users situations, habits, and intentions. Self-adaptive applications autonomously adapt to changing contexts without asking the user. However, the self-adaptive behaviour lacks of success if it does not correspond to the users personal interaction habits and intentions, particularly for complex scenarios with a high degree of user interaction. Concerning the interaction design, such adaptations can be irritating and distracting for the user if they do not match the current situation. In this article we provide a solution how to integrate the user in the self-adaptation feedback loop. The user will be able to influence the adaptation behaviour at run-time and in the long term by setting individual preferences. Consequently, we achieve a harmonisation between full application autonomy and user control. We implemented our generic concepts by extending an existing self-adaptation middleware with capabilities to respect the users application focus and interaction behaviour. A notification-based solution for user participation has been evaluated in a substantial user study with 62 participants. Although participants perceived much better control with our solution, the study made clear that notification design is specific for each adaptation type.

Designing socio-technical applications for ubiquitous computing: results from a multidisciplinary case study

A major challenge for ubiquitous system design is creating applications that are legal-compatible and accepted by their intended users. Todays European data protection principles contradict the ideas of ubiquitous computing. Additionally, users have to deal with unconventional interaction concepts leading to a low amount of trust and acceptance in such systems. Current development approaches do not sufficiently cover these concerns, as they do not systematically incorporate expertise from the relevant disciplines. We present a novel development approach for ubiquitous systems that explicitly addresses these concerns. Our primary task was to manage the increased number of stakeholders and dependencies, respectively conflicts between requirements of the particular disciplines. The approach incorporates predefined artifacts and a defined workflow with responsibilities, as well as suggesting how to develop mutual understanding. We apply this multidisciplinary approach to develop the ubiquitous application Meet-U.

Achieving user participation for adaptive applications

Adaptive applications establish the basis for many ubiquitous computing scenarios as they can dynamically adapt to changing contexts. But adaptive applications lack of success when the adaptive behaviour does not correspond to the users interaction habits. A user study revealed that such applications are not satisfying for complex scenarios with a high degree of user interaction. We claim that there must be a trade-off between automation and user participation. By extending an existing adaptation middleware with capabilities to respect user preference and interaction behaviour we demonstrate how to integrate the user in the self-adaptation loop. Interdisciplinary results from the fields of usability engineering and interaction design include the need for an adaptation notification concept to avoid mismatching adaptation behaviour.

Development support for QoS-aware service-adaptation in ubiquitous computing applications

In ubiquitous computing environments services may be discovered and bound dynamically. Adaptive applications may utilize such services to improve their offered functional and nonfunctional properties. Generally, the adaptation decision depends on the quality of service (QoS) of discovered services. The development of such adaptive applications is a complex, challenging task. In this paper, we present a general methodology for facilitating the development of QoS-dependent self-adaptive applications. We present several lessons learned from application case studies using the new approach.

A personality based design approach using subgroup discovery

To facilitate user-centered software engineering, developers need an easy to grasp understanding of the user. The use of personas helps to keep specific user needs in mind during the design process. Technology acceptance is of particular interest for the design of innovative applications previously unknown to potential users. Therefore, our research focuses on defining a typology of relevant user characteristics with respect to technology acceptance and transferring those findings to the description of personas. The presented work focuses on the statistical relationship between technology acceptance and personality. We apply sub-group discovery as a statistical tool. Based on the statistically derived subgroups and patterns we define the mentioned personas to help developers to understand different forms of technology acceptance. By integrating the specifically defined personas into existing methods in the field of software engineering the feasibility of the presented approach is demonstrated.

Users' View on Context-Sensitive Car Advertisements

Cars are ubiquitous and offer large and often highly visible surfaces that can be used as advertising space. Until now, advertising in this domain has focused on commercial vehicles, and advertisements have been painted on and were therefore static, with the exception of car-mounted displays that offer dynamic content. With new display technologies, we expect static displays or uniformly-painted surfaces (e.g. onto car doors or the sides of vans and trucks) to be replaced with embedded dynamic displays. We also see an opportunity for advertisements to be placed on non-commercial cars: results of our online survey with 187 drivers show that more than half of them have an interest in displaying advertising on their cars under two conditions: (1) they will receive financial compensation, and (2) there will be a means for them to influence the type of advertisements shown. Based on these findings, as well as further interviews with car owners and a car fleet manager, we discuss the requirements for a context-aware advertising platform, including a context-advertising editor and contextual content distribution system. We describe an implementation of the system that includes components for car owners to describe their preferences and for advertisers to contextualize their ad content and distribution mechanism.

Ableitung von Anforderungen zum Adaptionsverhalten in ubiquitären adaptiven Anwendungen

Das Adaptionsverhalten in selbst-adaptiven Anwendungen in der Softwareentwicklung wird, wie auch andere Funktionalitat, durch Anforderungen bestimmt. Wirkt sich das daptionsverhalten auf die Anwendungsarchitektur aus, so werden die zugehorigen Anforderungen bereits am Anfang der Umsetzung benotigt. Diese Arbeit beantwortet die Frage, welche Anforderungen erfasst werden mussen und wie diese systematisch hergeleitet werden konnen. Das Vorgehen lehnt sich dabei an die Entwicklungsmethodik und das Rahmenwerk des MUSIC-Projektes an und wird anschliesend an einem Fallbeispiel demonstriert. Dieses lasst sich ebenfalls fur andere Entwicklungsprojekte und -ansatze ubernehmen, deren Ziel es ist, selbst-adaptive Anwendungen zu erstellen. Mit dem Vorgehen ist eine effektive Ausarbeitung des Adaptionsverhalten anhand von Anforderungen bereits zu Beginn der Umsetzung moglich.

Challenging the Need for Transparency, Controllability, and Consistency in Usable Adaptation Design

Adaptive applications constitute the basis for many ubiquitous computing scenarios as they can dynamically adapt to changing contexts. The usability design principles transparency, controllability, and consistency have been recommended for the design of adaptive interfaces. However, designing self-adaptive applications that may act completely autonomous is still a challenging task because there is no set of usability design guidelines. Applying the three principles in the design of the five different adaptations of the mobile adaptive application Meet-U revealed as difficult. Based on an analysis of the design problem space, we elaborate an approach for the design of usable adaptations. Our approach is based on a notification design concept which calculates the attention costs and utility benefits of notified adaptations by varying the design aspects transparency and controllability. We present several designs for the adaptations of Meet‑U. The results of a user study shows that the notification design approach is beneficial for the design of adaptations. Varying transparency and controllability is necessary to adjust an adaptation’s design to the particular context of use. This leads to a partially inconsistent design for adaptations within an application.

User intervention in self-adaptive context-aware applications

Self-adaptive context-aware applications are designed to take decisions automatically and to relieve the user from switching an application manually from one mode of operation to another. However, our experience with self-adaptive applications has shown that the user does not always appreciate being out of the decision loop. Autonomous application behavior may not always meet the users expectations and adaptations may be inappropriate in certain situations. We investigated several techniques how to bring the user back into the loop. In this paper we present a comprehensive discussion of requirements as well as our solutions for user intervention in self-adaptive applications.

Designing Usable Adaptations

Ubiquitous computing systems are able to adapt their functionality, behaviour, and interface characteristics according to the user’s context. The user’s context is computed by e.g. sensor data, data about the user’s current activity, or the environment. By performing adaptations, these systems attempt to adequately support users in accomplishing their tasks in any situation. However, adaptations that impact the user interface, e.g. by integration of services, may cause usability problems, for example when they disrupt the user in accomplishing a task. There is no established set of guidelines or comprehensive design solutions to overcome potential usability problems in adaptive applications. In this chapter we present our notification-based design approach, which was beneficial to design usable adaptations for the adaptive application Meet-U. We analyse the results of a user study with 52 potential users in which we have evaluated the usability of our notification-based design solutions. We identified suitable design solutions for five different adaptations providing different supportive services in different contexts of use. These services are: navigational services, event services, a device muting service, and an environmental service. We also exposed the general requirement for a task-specific and context-specific design for adaptations.