A steadily increasing number of notifications, auditory, visual or ambient, competes for the user’s attention. Frequent unsuitable notifications can lead to a breakdown in efficiency and increase error rates. This paper compares the effectiveness, disruptiveness, and user experience of three different notification modalities: On-Object, ambient On-Environment, and On-Smartphone notifications. In a user study with 24 participants, we evaluate the three notification modalities during a cooking task where users were frequently exposed to notifications. Our results show that ambient On-Environment notifications minimize the time in which users can resume their primary task. Ambient On-Environment notifications were also perceived as least disrupting compared to the other two notification modalities. We discuss the design requirements for non-disruptive notifications in smart home environments and conclude with future strategies for notifying users at different urgency levels.

Ubiquitous, situated, and physical visualizations create entirely new possibilities for tasks contextualized in the real world, such as doctors inserting needles. During the development of situated visualizations, evaluating visualizations is a core requirement. However, performing such evaluations is intrinsically hard as the real scenarios are safety-critical or expensive to test. To overcome these issues, researchers and practitioners adapt classical approaches from ubiquitous computing and use surrogate empirical methods such as Augmented Reality (AR), Virtual Reality (VR) prototypes, or merely online demonstrations. This approach's primary assumption is that meaningful insights can also be gained from different, usually cheaper and less cumbersome empirical methods. Nevertheless, recent efforts in the Human-Computer Interaction (HCI) community have found evidence against this assumption, which would impede the use of surrogate empirical methods. Currently, these insights rely on a single investigation of four interactive objects. The goal of this work is to investigate if these prior findings also hold for situated visualizations. Therefore, we first created a scenario where situated visualizations support users in do-it-yourself (DIY) tasks such as crafting and assembly. We then set up five empirical study methods to evaluate the four tasks using an online survey, as well as VR, AR, laboratory, and in-situ studies. Using this study design, we conducted a new study with 60 participants. Our results show that the situated visualizations we investigated in this study are not prone to the same dependency on the empirical method, as found in previous work. Our study provides the first evidence that analyzing situated visualizations through different empirical (surrogate) methods might lead to comparable results.

Smart speakers become increasingly ubiquitous in our homes. Consequently, we need to study how smart speakers affect the members of a household. Understanding the adoption of a smart speaker can assure it does not negatively influence the social dynamics within a household and create opportunities for further assistance. We deployed an Amazon Echo dot in nine households with 20 inhabitants who were new smart speaker users. We conducted multiple interviews, inquiring how a smart speaker was integrated into a household from day one. We investigated the development of social rules around using the device and how the smart speaker was appropriated. Users developed different strategies of using the device which altered social behaviours in some households. Further, we identified barriers and unmet requirements in introducing smart speakers to home environments. Our work contributes to an understanding of ubiquitous assistance for user groups at home.

With the rise of the Internet of Things, home appliances become connected and they can proactively provide status information to users. Facing a steadily increasing number of notification sources, it is unclear how information from smart home devices should be provided without overloading the users’ attention. In this paper, we investigate the design of non-urgent smart home notifications using a smart plant system. Based on feedback from focus groups, we designed four notification types and compared them in an eight-week in-situ study. We show that notifications displayed on smart home devices are preferred to those received on smartphones. Event-based notifications are unobtrusive, actionable and are preferred to persistent notifications. We derive guidelines that address the need of being in control, opportune locations for notification delivery at opportune moments, notification blindness, the importance of discretizing continuous information, and combining related notifications.

Empirical studies are a cornerstone of HCI research. Technical progress constantly enables new study methods. Online surveys, for example, make it possible to collect feedback from remote users. Progress in augmented and virtual reality enables to collect feedback with early designs. In-situ studies enable researchers to gather feedback in natural environments. While these methods have unique advantages and disadvantages, it is unclear if and how using a specific method affects the results. Therefore, we conducted a study with 60 participants comparing five different methods (online, virtual reality, augmented reality, lab setup, and in-situ) to evaluate early prototypes of smart artifacts. We asked participants to assess four different smart artifacts using standardized questionnaires. We show that the method significantly affects the study result and discuss implications for HCI research. Finally, we highlight further directions to overcome the effect of the used methods.

Notifications are an essential feature of smartphones. While they support users in staying up-to-date, they are also a prominent source of interruptions. A deeper understanding of mobile notifications is required to avoid adverse effects. However, assessing mobile notifications is challenging as user studies on mobile notifications are typically conducted in-situ. Surveying users may lead to additional interruptions, and the content of notifications is inherently private. In this paper, we introduce a privacy-aware system for annotating mobile notifications in user studies. In an in-situ case study, participants annotated their notifications for one week. Participants perceived 38.91% of their notifications as not important and over half (51.75%) as non-urgent. Only 6.33% of the notifications were rated as both very important and very urgent. We discuss influencing factors, including a breakdown of messaging notifications, and implications for future smart notification systems that continue to fulfill users' information need while respecting their digital well-being.

As architects usually decide on the shape and look of windows during the design of buildings, opportunities for interactive windows have not been systematically explored yet. In this work, we extend the vision of sustainable and comfortable adaptive buildings using interactive smart windows. We systematically explore the design space of interactive windows to chart requirements, constraints, and challenges. To that end, we built proof-of-concept prototypes of smart windows with fine-grained control of transparency. In two studies, we explored user attitudes towards interactive windows and elicited control methods. We found that users understand and see potential for interactive windows at home. We provide specific usage contexts and specify interactions that may facilitate domestic applications. Our work illustrates the concept of interactive smart windows and provides insights regarding their design, development, and user controls for adaptive walls. We identify design dimensions and challenges to stimulate further development in the domain of adaptive buildings.

Tactile overlays for touch-screen devices are an opportunity to display content for users with visual impairments. However, when users switch tactile overlays, the displayed content on the touch-screen devices still correspond to the previous overlay. Currently, users have to change the displayed content on the touch-screen devices manually which hinders a fluid user interaction. In this paper, we introduce self-identifying overlays - an automated method for touch-screen devices to identify tactile overlays placed on the screen and to adapt the displayed content based on the applied tactile overlay. We report on a pilot study with two participants with visual impairments to evaluate this approach with a functional content exploration application based on an adapted textbook.

Notifications on mobile devices are a prominent source of interruptions. Previous work suggests using opportune moments to deliver notifications to reduce negative effects. In this paper, we instead explore the manual deferral of notifications. We developed an Android app that allows users to "snooze" mobile notifications for a user-defined amount of time or to a user-defined point in time. Using this app, we conducted a year-long in-the-wild study with 295 active users. To complement the findings, we recruited 16 further participants who used the app for one week and subsequently interviewed them. In both studies, snoozing was mainly used to defer notifications related to people and events. The reasons for deferral were manifold, from not being able to attend notifications immediately to not wanting to. Daily routines played an important role in the deferral of notifications. Most notifications were deferred to the same day or next morning, and a deferral of more than two days was an exception. Based on our findings, we derive design implications that can inform the design of future smart notification systems.

Calendars are an essential tool for users to manage their daily schedules. With the expanding availability of Internet of Things (IoT) devices and smart home appliances, more and more connected devices appear in the homes of users. Some of these devices have the potential to complement, extend or even replace existing physical and digital calendars. However, little is known about how these devices should display calendar information without overwhelming users and negatively influencing their digital well-being. In this paper, we report the results of a lab study with 18 participants in which we compared calendars on seven different types of devices in the smart home context, from existing smartphone apps to novel e-paper displays and smart mirrors. We developed a smart calendar platform as a research probe and provide first insights into how different devices should convey information in future smart homes.

Regular physical activity reduces the risks of illness, obesity, and falling. Thus, many personal devices support users in monitoring their physical activity to initiate behavior changes. However, activity data is prone to measurement errors; for example a user is seated but typing increases the step count. Such false positives could be easily detected if data from multiple sensors would be connected. We envision a system that combines data from multiple sensors in our surroundings to reduce such measurement errors. Furthermore, the system shows the user's historical data for the past seven days, the activity level of the current day, and a forecast about physical activity for the next seven days in an artistic and configurable digital wall painting. We argue that this strengthens connectedness and privacy. We are convinced that our system can help to increase user's trust in activity data and raise awareness for behavior change regarding physical activity.

Wearable devices like smart watches or eye-wear computers are storing a myriad of personal information. Today, wearable devices support input techniques such as speech and gesture input. These user input methods however, are not well suited for authentication. With the development of smart textiles the design space for interaction for small smart devices can be increased. In this paper, we present the concept of FabricID a system which identifies users' hand-prints with a smart textile integrated into the sleeve of the user. To evaluate our concept, we recorded hand-prints of 16 users. We classified all recorded hand-prints and received an identification rate of 82.5% for all 16 users and on average 93.62% for groups of 4 users.

Many countries are confronted with aging societies. With the increasing need for elder care, it is necessary to investigate how technology can support aging in place. In this paper, we propose an ambient smart calendar system that supports the self-sufficiency and activeness of older adults. We report the results of a survey of older adults on their use of physical and digital calendars. Based on the results, we developed Caloo (Calendar of opportunities) - a prototypical smart wall calendar which supports older users by generating awareness about their daily schedules as well as supporting them in remaining active in their lives through event suggestions. We evaluated Caloo in a study with retired older adults. Overall, we received positive feedback and identified data sources for events, which the smart calendar can suggest to the user. Our results indicate the potential of deploying an ambient and pervasive smart calendar system that supports aging in place.

Smart devices have arrived in our everyday lives. Being able to notify the user about events is a core feature of these devices. Related work investigated interruptions caused by notifications on single devices. In this paper, we investigate notifications in multi-device environments by analyzing the results of a week-long in-situ study with 16 participants. We used the Experience Sampling Method (ESM) and recorded the participants' interaction with smartphones, smartwatches, tablets and PCs. Disregarding the type or content of notifications, we found that the smartphone is the preferred device on which to be notified. Further, we found that the proximity to the device, whether it is currently being used and the user's current location can be used to predict if the user wants to receive notifications on a device. The findings can be used to design future multi-device aware smart notification systems.