Chat Wacharamanotham

FingerFlux: near-surface haptic feedback on tabletops

We introduce FingerFlux, an output technique to generate near-surface haptic feedback on interactive tabletops. Our system combines electromagnetic actuation with permanent magnets attached to the users hand. FingerFlux lets users feel the interface before touching, and can create both attracting and repelling forces. This enables applications such as reducing drifting, adding physical constraints to virtual controls, and guiding the user without visual output. We show that users can feel vibration patterns up to 35 mm above our table, and that FingerFlux can significantly reduce drifting when operating on-screen buttons without looking.

Evaluating swabbing: a touchscreen input method for elderly users with tremor

Elderly users suffering from hand tremor have difficulties interacting with touchscreens because of finger oscillation. It has been previously observed that sliding ones finger across the screen may help reduce this oscillation. In this work, we empirically confirm this advantage by (1) measuring finger oscillation during different actions and (2) comparing error rate and user satisfaction between traditional tapping and swabbing in which the user slides his finger towards a target on a screen edge to select it. We found that oscillation is generally reduced during sliding. Also, compared to tapping, swabbing resulted in improved error rates and user satisfaction. We believe that swabbing will make touchscreens more accessible to senior users with tremor.

FabriTouch: exploring flexible touch input on textiles

Touch-sensitive fabrics let users operate wearable devices unobtrusively and with rich input gestures similar to those on modern smartphones and tablets. While hardware prototypes exist in the DIY crafting community, HCI designers and researchers have little data about how well these devices actually work in realistic situations. FabriTouch is the first flexible touch-sensitive fabric that provides such scientifically validated information. We show that placing a FabriTouch pad onto clothing and the body instead of a rigid support surface significantly reduces input speed but still allows for basic gestures. We also show the impact of sitting, standing, and walking on horizontal and vertical swipe gesture performance in a menu navigation task. Finally, we provide the details necessary to replicate our FabriTouch pad, to enable both the DIY crafting community and HCI researchers and designers to build on our work.

Knobology Revisited: A Comparison of User Performance between Tangible and Virtual Rotary Knobs

We present an experimental comparison of tangible rotary knobs and touch-based virtual knobs in three output conditions: eyes-on, eyes-free, and peripheral. Twenty participants completed a simple rotation task on a interactive surface with four different input techniques (two tangibles and two virtual touch widgets) in the three output conditions, representing the distance from the locus of attention. We found that users were in average 20% faster using tangible knobs than using the virtual knobs. We found that tangible knobs retains performance even if they are not in the locus of attention of the users. We provide four recommendations of suit- able choosing knobs based on tasks and design constraints.

Statsplorer: Guiding Novices in Statistical Analysis

Each step of statistical analysis requires researchers to make decisions based on both statistical knowledge and the knowledge of their own data. For novice analysts, this is cognitively demanding and can lead to mistakes and misinterpretations of the results. We present Statsplorer, a software that helps novices learn and perform inferential statistical tests. It lets the user kick-start data analysis from their research questions. Statsplorer automatically tests necessary statistical assumptions and uses visualizations to guide the user in both selecting statistical tests and interpreting the results. We compared Statsplorer with a statistics lecture and investigated how Statsplorer prepares novices for learning statistics in an AB/BA crossover experiment. The results indicates that using Statsplorer prior to the lecture leads to significantly better test scores in understanding statistical assumptions and choosing appropriate statistical tests. Statsplorer is open-source and is available online at: http://hci.rwth-aachen.de/statsplorer.

Understanding finger input above desktop devices

Using the space above desktop input devices adds a rich new input channel to desktop interaction. Input in this elevated layer has been previously used to modify the granularity of a 2D slider, navigate layers of a 3D body scan above a multitouch table and access vertically stacked menus. However, designing these interactions is challenging because the lack of haptic and direct visual feedback easily leads to input errors. For bare finger input, the users fingers needs to reliably enter and stay inside the interactive layer, and engagement techniques such as midair clicking have to be disambiguated from leaving the layer. These issues have been addressed for interactions in which users operate other devices in midair, but there is little guidance for the design of bare finger input in this space. In this paper, we present the results of two user studies that inform the design of finger input above desktop devices. Our studies show that 2 cm is the minimum thickness of the above-surface volume that users can reliably remain within. We found that when accessing midair layers, users do not automatically move to the same height. To address this, we introduce a technique that dynamically determines the height at which the layer is placed, depending on the velocity profile of the users initial finger movement into midair. Finally, we propose a technique that reliably distinguishes clicking from homing movements, based on the users hand shape. We structure the presentation of our findings using Buxtons three-state input model, adding additional states and transitions for above-surface interactions.

Moving Transparent Statistics Forward at CHI

Transparent statistics is a philosophy of statistical reporting whose purpose is scientific advancement rather than persuasion. We ran a SIG at CHI 2016 to discuss problems and limitations in statistical practices in HCI and options for moving the field towards clearer and more reliable ways of writing about experiments, and received an overwhelming response. This SIG resulted in rough drafts of reviewer guidelines, resources for authors, and other suggestions for advancing a vision of transparent statistics within the field; this year, we propose a concentrated one-day writing workshop to develop those documents into a polished state with input from a diverse cross-section of the CHI community.

Fillables: everyday vessels as tangible controllers with adjustable haptics

We introduce Fillables: low-cost and ubiquitous everyday vessels that are appropriated as tangible controllers whose haptics are tuned ad-hoc by filling, e.g., with water. We show how Fillables can assist users in video navigation and drawing tasks with physical controllers whose adjustable output granularity harmonizes with their haptic feedback. As proof of concept, we implemented a drawing application that uses vessels to control a virtual brush whose stroke width corresponds to the filling level. Furthermore, we found that humans can distinguish nine levels of haptic feedback when sliding water-filled paper cups (300 ml capacity) over a wooden surface. This discrimination follows Webers Law and was facilitated by sloshing of water.

How we gesture towards machines: an exploratory study of user perceptions of gestural interaction

This paper explores if people perceive and perform touchless gestures differently when communicating with technology vs. with humans. Qualitative reports from a lab study of 10 participants revealed that people perceive differences in the speed of performing gestures, sense of enjoyment, feedback from the communication target. Preliminary analysis of 1200 gesture trials of motion capture data showed that hand shapes were less taut when communicating to technology. These differences provide implications for the design of gestural user interfaces that use symbolic gestures borrowed from human multimodal communication.

Model Based Processing of Swabbing Movements on Touch Screens to Improve Accuracy and Efficacy for Information Input of Individuals Suffering from Kinetic Tremor

As a result of demographic change the average age of many western populations increases, accompanied with age-related disease patterns. Especially tremor symptoms rise accordingly, aggravating a barrier free interaction with information systems. In order to maintain a self determined lifestyle at home, new technologies and methods need to be introduced, especially for application in health care and telemedical scenarios. Hence, a new direct input technique based on wiping movements on touch screens has been developed. The combination of a new input concept and applying regular commercially available technologies helps to avoid high costs for acquisition and therefore makes it marketable. While making an input on the touch screen the precise characteristics of every wiping movement can be tracked and is used for computation of the desired entry. The efficacy of this approach was evaluated within a clinical study with n=15 subjects. The results show that the error ratio for inputs by tremor patients can be significantly reduced in comparison to a virtual keyboard, depending on tremor strength and form. The learning curve for first time users is very steep and tends to result in inputs that are only slightly steady than purposeful movements to standard buttons and keys.