We studied the memorability of free-form gesture sets for invoking actions. We compared three types of gesture sets: user-defined gesture sets, gesture sets designed by the authors, and random gesture sets in three studies with 33 participants in total. We found that user-defined gestures are easier to remember, both immediately after creation and on the next day (up to a 24% difference in recall rate compared to pre-designed gestures). We also discovered that the differences between gesture sets are mostly due to association errors (rather than gesture form errors), that participants prefer user-defined sets, and that they think user-defined gestures take less time to learn. Finally, we contribute a qualitative analysis of the tradeoffs involved in gesture type selection and share our data and a video corpus of 66 gestures for replicability and further analysis.

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Memorability of pre-designed and user-defined gesture sets

As researchers and industry alike are proposing TV interfaces that use gestures in their designs, understanding users' preferences for gesture commands becomes an important problem. However, no rules or guidelines currently exist to assist designers and practitioners of such interfaces. The paper presents the results of the first study investigating users' preferences for free-hand gestures when controlling the TV set. By conducting an agreement analysis on user-elicited gestures, a set of gesture commands is proposed for basic TV control tasks. Also, guidelines and recommendations issued from observed user behavior are provided to assist practitioners interested in prototyping free-hand gestural designs for the interactive TV.

User-defined gestures for free-hand TV control

The purpose of this paper is to develop a comprehensive research model that can explain potential customers’ behavioral intentions to adopt and use smart home services.,This study proposes and validates a new theoretical model that extends the theory of planned behavior. Partial least squares analysis is employed to test the research model and corresponding hypotheses on data collected from 216 survey samples.,Mobility, security/privacy risk, and trust in the service provider are important factors affecting the adoption of smart home services.,To increase potential users’ adoption rate, service providers should focus on developing mobility-related services that enable people to access smart home services while on the move using mobile devices via control and monitoring functions.,This study is the first empirical attempt to examine user acceptance of smart home services, as most of the prior literature has concerned technical features.

User acceptance of smart home services: an extension of the theory of planned behavior

Mobile phones seem to present the perfect user interface for interacting with smart environments, e.g. smart-home systems, as they are nowadays ubiquitous and equipped with an increasing amount of sensors and interface components, such as multi-touch screens. After giving an overview on related work this paper presents the adapted design methodology proposed by Wobbrock et al. (2009) for the development of a gesture-based user interface to a smart-home system. The findings for the new domain, device and gesture space are presented and compared to findings by Wobbrock et al. (2009) . Three additional steps are described: A small pre-test survey, a mapping and a memory test and a performance test of the implemented system. This paper shows the adaptability of the approach described by Wobbrock et al. (2009) for three-dimensional gestures in the smart-home domain. Elicited gestures are described and a first implementation of a user interface based on these gestures is presented.

I'm home: Defining and evaluating a gesture set for smart-home control

For more than two decades, capacitive sensing has played a prominent role in human-computer interaction research. Capacitive sensing has become ubiquitous on mobile, wearable, and stationary devices - enabling fundamentally new interaction techniques on, above, and around them. The research community has also enabled human position estimation and whole-body gestural interaction in instrumented environments. However, the broad field of capacitive sensing research has become fragmented by different approaches and terminology used across the various domains. This paper strives to unify the field by advocating consistent terminology and proposing a new taxonomy to classify capacitive sensing approaches. Our extensive survey provides an analysis and review of past research and identifies challenges for future work. We aim to create a common understanding within the field of human-computer interaction, for researchers and practitioners alike, and to stimulate and facilitate future research in capacitive sensing.

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Finding Common Ground: A Survey of Capacitive Sensing in Human-Computer Interaction

We present CapWidgets, passive tangible controls for capacitive touch screens. CapWidgets bring back physical controls to off-the-shelf multi-touch surfaces as found in mobile phones and tablet computers. While the user touches the widget, the surface detects the capacitive marker on the widget's underside. We study the relative performance of this tangible interaction with direct multi-touch interaction and our experimental results show that user performance and preferences are not automatically in favor of tangible widgets and careful design is necessary to validate their properties.

CapWidgets: tangile widgets versus multi-touch controls on mobile devices

Smartphones have become an indispensable part of everyday life. By this time, push notifications are at the core of many apps, proactively pushing new content to users. These notifications may raise awareness, but also have the downside of being disruptive. In this paper we present a laboratory study investigating users' attitudes towards notifications and how they deal with notification settings on their smartphones. Permission requests for sending push notifications on iOS don't inform the user about the nature of notifications of this app, leaving the user to make a rather uninformed choice on whether to accept or deny. We show that requests including explanations are significantly more likely to be accepted. Our results further indicate that apart from being disruptive, notifications may create stress due to information overload. Notification settings, once assigned a preset, are rarely changed, although not necessarily matching the favored one.

/pdf/assessing-the-relationship-between-technical-affinity-stress-1w05w4x3u4.pdf

Assessing the Relationship between Technical Affinity, Stress and Notifications on Smartphones

This paper describes the analysis of established and new questionnaires concerning their applicability for the assessment of quality aspects of multimodal systems. To this purpose, an experiment with 27 participants interacting with a a smart-home system via a voice interface, a smartphone-based interface and a multimodal interface, was conducted. Interaction parameters were assessed and related to constructs measured with these questionnaires. The results indicate that some of the questionnaires are suitable for evaluating multimodal interfaces. On the basis of correlations with interaction parameters subscales of these questionnaires can be mapped to quality aspects, such as effectiveness and efficiency. Recommendations are given how to meet two important evaluation requirements, namely which questionnaire to use for comparing two or more systems or system versions and how to identify factors or components in a system that have to be improved. This is another step forward to establish evaluation methods for multimodal systems.

Evaluating multimodal systems: a comparison of established questionnaires and interaction parameters

Notifications on smartphones are ubiquitous; they are providing a broad range of information, from rather technical (e.g. app updates) to interpersonal (e.g. a message from a friend). The disruptive nature poses the challenge of finding opportune moments for delivery of notifications, and receptivity to notifications depends on various factors that include perceived urgency and time of delivery. This paper presents a case study with 126 000 participants investigating the effect of the factor time on receptivity to notifications on smartphones in the context of an advertising service. Results show significant differences for weekdays and time of day regarding response times and number of notification-triggered application launches. We conclude with a discussion on the key findings and propose design implications for push notification campaigns.

Tilo Westermann

Papers

I'm home: Defining and evaluating a gesture set for smart-home control

CapWidgets: tangile widgets versus multi-touch controls on mobile devices

Assessing the Relationship between Technical Affinity, Stress and Notifications on Smartphones

Evaluating multimodal systems: a comparison of established questionnaires and interaction parameters

Smartphone Notifications in Context: a Case Study on Receptivity by the Example of an Advertising Service