Moritz Wittenhagen

DragLocks: handling temporal ambiguities in direct manipulation video navigation

Direct manipulation video navigation (DMVN) systems allow to navigate inside video scenes by spatially manipulating objects in the video. Problems arise when dealing with temporal ambiguities where a time span is projected onto a single point in image space, e.g., when objects stop moving. Existing DMVN systems deal with these cases by either disabling navigation on the paused object or by allowing jumps in the timeline. Both of these workarounds are undesirable as they introduce inconsistency or provoke loss of context. We analyze current practices regarding temporal ambiguities and introduce two new methods to visualize and navigate object pauses. User tests show that the new approaches are better suited for navigation in scenes containing temporal ambiguities and are rated higher in terms of user satisfaction.

How tools in IDEs shape developers' navigation behavior

Understanding source code is crucial for successful software maintenance, and navigating the call graph is especially helpful to understand source code [12]. We compared maintenance performance across four different development environments: an IDE without any call graph exploration tool, a Call Hierarchy tool as found in Eclipse, and the tools Stacksplorer [7]and Blaze [11]. Using any of the call graph exploration tools more developers could solve certain maintenance tasks correctly. Only Stacksplorer and Blaze, however, were also able to decrease task completion times, although the Call Hierarchy offers access to a larger part of the call graph. To investigate if this result was caused by a change in navigation behavior between the tools, we used a set of predictive models to create formally comparable descriptions of programmer navigation. The results suggest that the decrease in task completion times has been caused by Stacksplorer and Blaze promoting call graph navigation more than the Call Hierarchy tool.

Pinstripe: eyes-free continuous input anywhere on interactive clothing

We present Pinstripe, a textile user interface element for eyes-free, continuous value input on smart garments that uses pinching and rolling a piece of cloth between your fingers. Input granularity can be controlled by the amount of cloth pinched. Pinstripe input elements are invisible, and can be included across large areas of a garment. Pinstripe thus addresses several problems previously identified in the placement and operation of textile UI elements on smart clothing.

Chronicler: Interactive Exploration of Source Code History

Exploring source code history is an important task for software maintenance. Traditionally, source code history is navigated on the granularity of individual files. This is not fine-grained enough to support users in exploring the evolution of individual code elements. We suggest to consider the history of individual elements within the tree structure inherent to source code. A history graph created from these trees then enables new ways to explore events of interest defined by structural changes in the source code. We present Tree Flow, a visualization of these structural changes designed to enable users to choose the appropriate level of detail for the task at hand. In a user study, we show that both Chronicler and the history aware timeline, two prototype systems combining history graph navigation with a traditional source code view, outperform the more traditional history navigation on a file basis and users strongly prefer Chronicler for the exploration of source code.

Me hates this: exploring different levels of user feedback for (usability) bug reporting

User feedback for deployed software systems ranges from simple one-bit-feedback to full-blown bug reports. While detailed bug reports are very helpful for the developers to track down problems, the expertise and commitment required from the user is high. We analyzed existing user report systems and propose a flexible and independent hard- and software architecture to collect user feedback. We report our results from a preliminary two-week user study testing the system in the field and discuss challenges and solutions for the collection of multiple levels of user feedback through different modalities.

Hybrid documents ease text corpus analysis for literary scholars

We present a study that explores how literary scholars interact with physical and digital documents in their daily work. Motivated by findings from this study, we propose refactoring the working environment of our target audience to improve the integration of digital material into established paper-centric processes. This is largely facilitated through the use of hybrid documents, i.e., cross-modal compound documents that employ a printed book for rich, tangible interaction in tandem with a digital component for matching interactive augmentation on a digital workbench. The results from two user studies in which we evaluated increasingly detailed prototypes demonstrate that this design offers better support for central workflows in literary studies than currently prevalent approaches.