Matthias Kranz

• Prof. Dr. rer. nat.
• Head of Department at Cyberagentur

The Internet of Things assumes that objects have digital functionality and can be identified and tracked automatically. The main goal of embedded interaction is to look at new opportunities that arise for interactive systems and the immediate value users gain. The authors developed various prototypes to explore novel ways for human-computer interac...

In this paper we introduce the design and development of the Learning Cube as a novel tangible learning appliance. Using the common shape of a cube we implemented a general learning platform that supports test based quizzes where questions and answers can be text or image based. Exploiting the physical affordances of the cube and augmenting it with...

Optical see-through head-mounted displays (OST HMDs) are a popular output medium for mobile Augmented Reality (AR) applications. To date, they lack efficient text entry techniques. Smartphones are a major text entry medium in mobile contexts but attentional demands can contribute to accidents while typing on the go. Mobile multi-display ecologies,...

Optical see-through head-mounted displays (OST HMDs) are a popular output medium for mobile Augmented Reality (AR) applications. To date, they lack efficient text entry techniques. Smartphones are a major text entry medium in mobile contexts but attentional demands can contribute to accidents while typing on the go. Mobile multi-display ecologies,...

Huge amounts of data are produced inside an industrial production plant every minute. This data is getting more accessible by higher network and computing capabilities. This poses an opportunity to apply methods in real time to support the reliability of production machines. In theory every time series, that is currently monitored by for a breach o...

Being able to fly is still a dream. Till today it's only possible with heavy use of technology. Video games incorporated flying as a fancy way of movement inspired by mythical creatures, gods and fantasies. In Virtual Reality, with its deep immersion, the avatar control, especially for flying, is still performed by physical controllers that lack to...

Optical see-through head-mounted displays (OST HMDs) typically display virtual content at a fixed focal distance while users need to integrate this information with real-world information at different depth layers. This problem is pronounced in body-proximate multi-display systems, such as when an OST HMD is combined with a smartphone or smartwatch...

Interdisciplinary teams and studies need new approaches to design prototypes using tools indistinguishable from the ones they are used to. We utilize a digital pen and physical paper, as the everyday life tools, to build a smart interface for laser-cutters, giving non-technical experienced people the possibility to rapidly, seamlessly, and collabor...

The quantified self-paradigm is well established. Its main purpose is to use numbers from sensors to derive self-knowledge. The massive availability of persuasive technology to monitor physiological parameters of humans made the paradigm available to a tremendous number of people. A multitude of different hard- and software platforms are available...

Optical see-through head-mounted displays (OST HMDs) typically display virtual content at a fixed focal distance while users need to integrate this information with real-world information at different depth layers. This problem is pronounced in body-proximate multi-display systems, such as when an OST HMD is combined with a smartphone or smartwatch...

Alphanumeric text entry is a challenge for Virtual Reality (VR) applications. VR enables new capabilities, impossible in the real world, such as an unobstructed view of the keyboard, without occlusion by the user's physical hands. Several hand representations have been proposed for typing in VR on standard physical keyboards. However, to date, thes...

We study the performance and user experience of two popular mainstream text entry devices, desktop keyboards and touchscreen keyboards, for use in Virtual Reality (VR) applications. We discuss the limitations arising from limited visual feedback, and examine the efficiency of different strategies of use. We analyze a total of 24 hours of typing dat...

In this study, we develop an electromagnetic-based haptic interface to provide controlled magnetic forces to the operator through a wearable haptic device (an orthopedic finger splint with single dipole moment) without position feedback. First, we model the electromagnetic forces exerted on a single magnetic dipole attached to the wearable haptic d...

We present HeadPhones (Headtracking + smartPhones), a novel approach for the spatial registration of multiple mobile devices into an ad hoc multi-display environment. We propose to employ the user's head as external reference frame for the registration of multiple mobile devices into a common coordinate system. Our approach allows for dynamic repos...

Pervasive computing was envisioned by pioneers like Mark Weiser but has yet to become an everyday technology in our society. The recent advances regarding Internet of Things, social computing, and mobile access technologies converge to make pervasive computing truly ubiquitous. The key challenge is to make simple and robust solutions for normal use...

Around-device interaction promises to extend the input space of mobile and wearable devices beyond the common but restricted touchscreen. So far, most around-device interaction approaches rely on instrumenting the device or the environment with additional sensors. We believe, that the full potential of ordinary cameras, specifically user-facing cam...

We investigate improvements to authentication on mobile touchscreen phones and present a novel extension to the widely used touchscreen pattern lock mechanism. Our solution allows including nodes in the grid multiple times, which enhances the resilience to smudge and other forms of attack. For example, for a smudge pattern covering 7 nodes, our app...

We present a novel approach for extending the input space around unmodified mobile devices. Using built-in front-facing cameras of unmodified handheld devices, GlassHands estimates hand poses and gestures through reflections in sunglasses, ski goggles or visors. Thereby, GlassHands creates an enlarged input space, rivaling input reach on large touc...

Background Coordinated multi-display environments from the desktop, second-screen to gigapixel display walls are increasingly common. Personal and intimate mobile and wearable devices such as head-mounted displays, smartwatches, smartphones and tablets are rarely part of such multi-device ecosystems. Methods We conducted a literature research and a...

Coordinated multi-display environments from the desktop, second-screen to gigapixel display walls are increasingly common. Personal and intimate mobile and wearable devices such as head-mounted displays, smartwatches, smartphones and tablets are rarely part of such multi-device ecosystems. With this paper, we contribute to a better understanding ab...

Designing mobile applications for elderly users can be very challenging. Their heterogeneous prior knowledge and abilities make user-centered design processes difficult. For that reasons, some measures are necessary to make the applications usable the majority of elderly people and to get useful feedback during the evaluation. In this paper, we sum...

Immersive AR environments are situated information spaces that employ the Augmented Reality display paradigm. They tightly couple abstract, digital information and physical elements present in the user's real-world environment. As a consequence of this mixed digital-physical spatiality, interface design has the chance to build upon the user's cogni...

Body proximate display environments can be formed by combining multiple hand-held, head-mounted, wrist-worn or other displays. Wearable displays such as smartwatches and smartglasses have the potential to extend the interaction capabilities of mobile users beyond a single display. However, the display ecosystem formed by multiple personal displays...

Data glasses do carry promising potential for hands-free interaction, but also raise various concerns amongst their potential users. In order to gain insights into the nature of those concerns, we investigate how potential usage scenarios are perceived by device users and their peers. We present results of a two-step approach: a focus group discuss...

In this paper, we study the concept of security zones as an intermediate layer of compartmentalization on mobile devices. Each of these security zones is isolated against the other zones and holds a different set of applications and associated user data and may apply different security policies. From a user point of view, they represent different c...

The adoption of NFC technology has taken longer than expected after its inception in 2004. Several projects on ticketing and payment are gaining momentum. However, the actual state of adoption of NFC is still unclear. As an alternative to consultants? prediction (which mostly prove wrong), this paper describes a gamification-based approach to motiv...

Forward collision warning systems, lane change assistants or cooperative adaptive cruise control are examples of safety relevant applications that rely on accurate relative positioning between vehicles. Current solutions estimate the position of an in-front driving vehicle by measuring the distance with a radar sensor, a laser scanner or a camera s...

{Ein regelmäß}iges körperliches Training kann altersbedingte Bewegungseinschränkungen aufgrund von nachlassenden Kräften entgegenwirken. Jedoch haben viele ältere Personen oft nicht die Möglichkeit und Motivation entsprechende Trainingsangebote wahrzunehmen. Aus diesem Grund wurden zwei mobile Trainingsanwendungen mit verschiedenen Trainingsansätze...

Designing mobile applications for elderly users can be very challenging. The heterogeneous prior knowledge and abilities of this user group make user-centered design processes difficult. Based on our experiences from the development and evaluation of a mobile fitness application for elderly users, we address potential difficulties in the design pro...

Gestural interaction has entered the automotive domain, allowing the driver to control secondary and tertiary functions of the vehicle. The design space ranges from mid-air gestures to surface-based gestures requiring little or no visual attention of the user. In this paper, we present an up-to-date survey on current gestural interaction methods in...

Large-scale research has gained momentum in the context of Mobile Human-Computer Interaction (Mobile HCI), as many aspects of mobile app usage can only be evaluated in the real world. In this chapter, we present findings on the challenges of research in the large via app stores, in conjunction with selected data collection methods (logging, self-re...

In densely populated areas, we currently see a paradigm shift in personal mobility. For the younger generation, car usership is gradually replacing the need of car ownership. However, for example, when relying on car sharing solutions, users often spontaneously drive cars they are not used to. Results are increased stress and a higher risk of accid...

Sharing information between traffic participants can improve traffic flow and safety. Currently, communication is mainly done via vehicle lighting such as brake lamps or turn signals. For enhanced information exchange, we propose using the exterior of vehicles as pervasive displays to present information that may be relevant to other traffic partic...

When driving an unknown car, the interaction with its user interfaces and the operation of (comfort) vehicle functions can be very challenging and thus cause safety concerns. However, this problem can be overcome already with a short learning and practicing phase. For this reason, we analyze the potential of gamification for exploring and practicin...

People do not always think and behave rationally. Behavioral economics has produced theories to explain when and why people make such allegedly irrational decisions, for example if it comes to spending money. However, humans tend to use reference points to judge and decide. Nowadays, mobile devices can work as flexible tools to create reference poi...

Location sharing systems often entail concerns about privacy when disclosing one’s position.Users worry that their location could be traced by people they do not know sufficiently well – a side effect of large friend lists in social networks. Earlier research observed large-scale networks such as Foursquare or Google Latitude. In this work, we inve...

Multimodality can make (especially mobile) device interaction more efficient. Sensors and communication capabilities of modern smartphones and tablets lay the technical basis for its implementation. Still, mobile platforms do not make multimodal interaction support trivial. Building multimodal applications requires various APIs with different parad...

Prototyping is an important part in research and development of tangible user interfaces (TUIs). On the way from the idea to a working prototype, new hardware prototypes usually have to be crafted repeatedly in numerous iterations. This brings us to think about virtual prototypes that exhibit the same functionality as a real TUI, but reduce the amo...

Mobile location recognition by capturing images of the environment (visual localization) is a promising technique for indoor navigation in arbitrary surroundings. However, it has barely been investigated so far how the user interface (UI) can cope with the challenges of the vision-based localization technique, such as varying quality of the query i...

Prototyping is an important part in research and development of tangible user interfaces (TUIs). On the way from the idea to a working prototype, new hardware prototypes usually have to be crafted repeatedly in numerous iterations. This brings us to think about virtual prototypes that exhibit the same functionality as a real TUI, but reduce the amo...

Saving money is usually a tedious task that requires a high degree of self-control for many of us. Some people have one or more specific savings targets in mind and thus need to prioritize them. We propose connecting a savings box with a personal smartphone. Thus, people become motivated to keep track of their savings for multiple targets. Using a...

Saving money is usually a tedious task that requires a high degree of self-control for many of us. Some people have one or more specific savings targets in mind and thus need to prioritize them. We propose connecting a savings box with a personal smartphone. Thus, people become motivated to keep track of their savings for multiple targets. Using a...

Advances in the fields of distributed computing, wireless sensor networks, ubiquitous computing and many more have facilitated the development of a plenitude of Intelligent Environments (IE). The development processes, underlying tools and methods have however not yet been in the focus of researchers. A significant amount of time has to be spent fo...

We consider the reasons why we organise books in a physical environment and investigate whether situating interactions with a smartphone could improve the user experience of e-readers. Our prototype uses the Kinect depth sensor to detect the position of a user in relation to sections of a physical bookshelf. We also built a mobile application that...

User authentication on publicly exposed terminals with established mechanisms, such as typing the credentials on a virtual keyboard, can be insecure e.g. due to shoulder surfing or due to a hacked terminal. In addition, username and password entry can be time-consuming and thus improvable with relation to usability. As security and comfort are ofte...

The ongoing evolution of mobile phones to "pocket computers" generated a demand for more and more applications to be ported to the mobile phone. Because a full security assessment for a whole mobile operating system would be prohibitively costly, currently security critical applications can not be implemented. We address this challenge by introduci...

In this paper, we review the use of gameful design in the automotive domain. Outside of vehicles the automotive industry is mainly using gameful design for marketing and brand forming. For in-vehicle applications and for applications directly connected to real vehicles, the main usage scenarios of gameful design are navigation, eco-driving and driv...

In previous work, we investigated possibilities of an architecture for the functional distributionof a vehicle-to-x (V2X) system on two devices with different capabilities. One of the devices is an in-vehicle onboard unit (OBU), the other a personal portable device (PPD), such as asmartphone or tablet PC. We developed three different concepts to sp...

A decisive factor for effective driver awareness and warning systems is the visualization of impor- tant and safety critical information for the driver. In previous work, we introduced a flexible two- component system that can visualize real time data from vehicle-to-x (V2X) communication [1]. In order to maximize the overall performance and reliab...

Self-reporting techniques, such as data logging or a diary, are frequently used in long-term studies, but prone to subjects’ forgetfulness and other sources of inaccuracy. We conducted a six-week self-reporting study on smartphone usage in order to investigate the accuracy of self-reported information, and used logged data as ground truth to compar...

The project PASSAge (Personalized Mobility, Assistance and Service Systems in an Aging Society), funded by the German Federal Ministry of Education and Research (BMBF, Bundesministerium für Bildung und Forschung) aims at the implementation of seamless mobility chains that smoothly connect private and public spaces with a special regard to the needs...

We present a novel user interface concept for indoor navigation which uses directional arrows and panorama images of decision points, such as turns, along the route. The interface supports the mental model of landmark-based navigation, can be used on- and offline, and is highly tolerant to localization inaccuracy. We evaluated the system in a real-...

We present a novel approach to authenticate and authorize a user, using her personal smartphone. The presented architecture is complemented with a proof-of-concept implementation. The implemented system architecture is based on a single sign-on solution (SSO), extended to allow the usage of the smartphone as authentication and authorization device....