Frederik Brudy

Touch me once and i know it's you!: implicit authentication based on touch screen patterns

Password patterns, as used on current Android phones, and other shape-based authentication schemes are highly usable and memorable. In terms of security, they are rather weak since the shapes are easy to steal and reproduce. In this work, we introduce an implicit authentication approach that enhances password patterns with an additional security layer, transparent to the user. In short, users are not only authenticated by the shape they input but also by the way they perform the input. We conducted two consecutive studies, a lab and a long-term study, using Android applications to collect and log data from user input on a touch screen of standard commercial smartphones. Analyses using dynamic time warping (DTW) provided first proof that it is actually possible to distinguish different users and use this information to increase security of the input while keeping the convenience for the user high.

CurationSpace: Cross-Device Content Curation Using Instrumental Interaction

For digital content curation of historical artefacts, curators collaboratively collect, analyze and edit documents, images, and other digital resources in order to display and share new representations of that information to an audience. Despite their increasing reliance on digital documents and tools, current technologies provide little support for these specific collaborative content curation activities. We introduce CurationSpace -- a novel cross-device system to provide more expressive tools for curating and composing digital historical artefacts. Based on the concept of Instrumental Interaction, CurationSpace allows users to interact with digital curation artefacts on shared interactive surfaces using personal smartwatches as selectors for instruments or modifiers (applied to either the whole curation space, individual documents, or fragments). We introduce a range of novel interaction techniques that allow individuals or groups of curators to more easily create, navigate and share resources during content curation. We report insights from our user study about peoples use of instruments and modifiers for curation activities.

SurfaceConstellations: A Modular Hardware Platform for Ad-Hoc Reconfigurable Cross-Device Workspaces

We contribute SurfaceConstellations, a modular hardware platform for linking multiple mobile devices to easily create novel cross-device workspace environments. Our platform combines the advantages of multi-monitor workspaces and multi-surface environments with the flexibility and extensibility of more recent cross-device setups. The SurfaceConstellations platform includes a comprehensive library of 3D-printed link modules to connect and arrange tablets into new workspaces, several strategies for designing setups, and a visual configuration tool for automatically generating link modules. We contribute a detailed design space of cross-device workspaces, a technique for capacitive links between tablets for automatic recognition of connected devices, designs of flexible joint connections, detailed explanations of the physical design of 3D printed brackets and support structures, and the design of a web-based tool for creating new SurfaceConstellation setups.

WRISTBAND.IO: Expanding Input and Output Spaces of a Smartwatch

Smartwatches are characterized by their small size designed for wearability, discretion, and mobile interactions. Most of the interactivity, however, is limited to the size of the display, introducing issues such as screen occlusion and limited information density. We introduce Wristband.io, a smartwatch with an extended interaction space along the wristband, enabling (i) back-of-band interaction using a touchpad, (ii) a low resolution ambient watchband display for off-screen notification, and (iii) tangible buttons for quick, eyes-free input. Insights gained through a study show that back-of-band input increases accuracy and task completion rates for smaller on-screen targets. We probe the design space of Wristband.io with three applications.

Is Anyone Looking? - Mediating Shoulder Surfing on Public Displays

When a person interacts with a display in an open area, sensitive information becomes visible to shouldersurfing passersby. While a person’s body shields small displays, shielding is less effective as display area increases. To mitigate this problem, we sense spatial relationships between the passerby, person and display. Awareness of onlookers is provided through visual cues: flashing screen borders, a 3D model mirroring the onlooker’s position and gaze, and an indicator that illustrates their gaze direction. The person can react with a gesture that commands the display to black out personal windows, or to collect them on one side. Alternately, the display will automatically darken screen regions visible by the onlooker, but leaving the display area shielded by the person’s body unaltered (thus allowing the person to continue their actions). The person can also invite the onlooker to collaborate with them via a gesture that reverses these protective mechanisms.

Investigating the Role of an Overview Device in Multi-Device Collaboration

The availability of mobile device ecologies enables new types of ad-hoc co-located decision-making and sensemaking practices in which people find, collect, discuss, and share information. However, little is known about what kind of device configurations are suitable for these types of tasks. This paper contributes new insights into how people use configurations of devices for one representative example task: collaborative co-located trip-planning. We present an empirical study that explores and compares three strategies to use multiple devices: no-overview, overview on own device, and a separate overview device. The results show that the overview facilitated decision- and sensemaking during a collaborative trip-planning task by aiding groups to iterate their itinerary, organize locations and timings efficiently, and discover new insights. Groups shared and discussed more opinions, resulting in more democratic decision-making. Groups provided with a separate overview device engaged more frequently and spent more time in closely-coupled collaboration.

SurfaceConstellation Applications: Use Cases of Ad-Hoc Reconfigurable Cross-Device Workspaces

SurfaceConstellations is a modular hardware platform that allows users to easily create their own novel cross-device environments by assembling multiple mobile surfaces with 3D printed link modules. Our platform combines the advantages of multi-monitor workspaces and multi-surface environments with the flexibility and extensibility of more recent cross-device setups. The platform includes a comprehensive library of 3D-printed link modules to connect and arrange tablets into new workspaces, several strategies for creating new setups, and a web-based visual configuration tool for creating new setups and automatically generating link modules. We will demonstrate different use-case applications across the design space of reconfigurable cross-device workspaces and the configuration tool.

Designing Ad-Hoc Cross Device Collaborations For Small Groups

The curation of historic documents is a difficult task as it requires to combine information and raw material from many different sources. Digital tools can support such a sensemaking task and group collaboration can help the discovery of knowledge. While most of peoples personal devices (such as phones, tablets and laptops) are connected to the internet, they are not aware of each others presence or relationship when in close proximity. Leveraging peoples personal devices and other devices in their surroundings provides an opportunity to support the curation of historic documents in ad hoc small group scenarios. I describe my motivation and a selection of related work, leading to requirements for such a system. I then state how I am planning to address these challenges and my current state of research, following two parallel tracks: building and testing technology as well as conducting observational studies and interviews to inform my designs.