Paper Reading #1: BiTouch and BiPad: designing bimanual interaction for hand-held tablets

Intro:

• BiTouch and BiPad: Designing Bimanual Interaction for Hand-Held Tablets 
• Wagner, Julie, Stéphane Huot, and Wendy E. Mackay. (2012). BiTouch and BiPad: Designing Bimanual Interaction for Hand-Held Tablets. Proceedings of the 2012 ACM annual conference on Human Factors in Computing Systems (CHI 2012), 2317-2326.
• Author Biographies:
• Julie Wagner received her Bachelor and Master degrees in computer science from RWTH Aachen University in Germany. She is currently in her third year of her Ph.D at Univ Paris-Sud, specializing in Computer Human Interaction. She has student teaching internship experience at her respected undergraduate and graduate universities. She published papers in CHI in each year from 2009-2012. Her paper in 2011 received the 'Best Paper Award'. Also, she has presentation experience at CHI in 2009 and 2010.
• Stéphane Huot received his Ph.D in computer science from University of Nantes and École des Mines de Nantes in 2005. His thesis covered computer human interaction. He is currently an associate professor at Université Paris-Sud 11. He received an award from 2011-2013 that granted him leave for research at Inria as a full time researcher.
• Wendy E. Mackay received a Bachelors from University of California, San Diego in psychology. She also earned her Masters degree from Northeastern University in experimental psychology. She has a Ph.D from MIT in Management Technological Innovation in 1990. She was professor in computer science department at University of Aarhus. She then became a senior researcher at Inria for two years before she was promoted to Research Director at Inria for the past ten years.

Summary:
The use of tablet like technological devices has become ubiquitous and essential to society over the past few years. Currently, tablets support different motions, such as tap or swipe of one hand, but do not support any sort of bimanual input. We know that bimanual interaction among desktops increases not only performance, but accuracy as well. Thus, the goal of the research is to implement a bimanual design and then evaluate its effectiveness while considering the need to hold the device.

The domain of the research focuses on Apple's iPad due to the larger screen than its relatives consisting of smartphones and PDAs. The conducted research will be implemented primarily through software due to the availability of additional iPad hardware purchases that stimulate bimanual usage, but are rather impractical.

First, the researchers discovered the unconscious methods that different users hold the iPad. They discovered a total of five positions with the fingers and thumb on the iPad border, for both landscape and portrait mode. The different positions can be seen in the figure below. Also, all participants of the study switched hands once while others changed holding positions several times throughout the experiment.

A BiPad toolkit with specific widgets for a test array of applications was then designed. This allowed the researchers to measure the utilization of the non-dominant hand based on the holding position the user chose. These BiPad zones appear on sides and corner of the screen. The implemented interaction among users include the tap, which is a single press, the chord, which allows multiple finger presses, and finally the gesture, which involves the sliding in an array of directions using one finger.

First, an example of the bimanual touch implementation includes a PDF in which the user is able to sift through using the dominant hand while simultaneously accessing the menu with the non-dominant holding hand via a side bar. Furthermore, a very useful design is custom buttons for the non-dominant hand such as a space bar for ease of typing and reduce movement of the dominant hand. Lastly, another potential use is spacial multiplexing in which is user is able to zoom in and out using the non-dominant hand while the dominant hand controls primary application usage.

Related work not referenced in the paper:
1) "Bimanual and Unimanual Image Alignment: An Evaluation of Mouse-Based Techniques"
2) "HabilisDraw DT: A Bimanual Tool-Based Direct Manipulation Drawing Environment"
3) "A Comparison of Tracking- and Controller-Based Input for Complex Bimanual Interaction in Virtual Environments"
4) "Exploring Bimanual Camera Control and Object Manipulation in 3D Graphics Interfaces"
5) "Bimanual Interaction for Tablet Computing"
6) "Motor Behaviour Models for Human-Computer Interaction"
7) "Actions and Consequences in Bimanual Interaction Are Represented in Different Coordinate Systems"
8) "Determining the Benefits of Direct-Touch, Bimanual, and Multifinger Input on a Multitouch Workstation"
9) "Bimanual Interaction on the Microsoft Office Keyboard"
10) "Harnessing the Benefits of Bimanual and Multi-finger Input for Supporting Grouping Tasks on Interactive Tabletops"

Overall, the work in these papers was extremely related to the BiPad and BiTouch research. In specific, they mostly deal with the interaction of technology and two human hands. Although, each inspects a different domain of usage, their ideas are still cohesive. For the most part, these papers all provided novel work. Their objectives was to increase the speed and utilization of technology. Although no gargantuan breakthroughs are to emerge from these works, there will still be small amendments to technology that may lead to a larger discovery along the line of technological advancement in the future. In fact, these papers did discuss related work appropriately. There is a wide range of research involving the usage of technology and bimanual utilization, so the papers each had a large reference point among one another.

Evaluation:
In terms of evaluation, the researchers set out to determine if the bimanual usage is quicker than a single hand and the trade-offs among the different orientation and hold types. The researchers used a team of subjects to properly evaluate their system. They independently analyzed the differences in technique, orientation, and hold. A special program was developed to test the quickness of two hands versus one through the tapping of buttons as they appeared on the screen. In order to properly monitor the effectiveness, the trial time, BiPad reaction time, BiPad completion time were all recorded for further analysis. In addition, the comfort level of the bimanual design versus the traditional one hand design was considered for a thorough and complete evaluation of this research.

First, the researchers discovered that bimanual taps were more efficient in both landscape and portrait mode than a single hand. However, bimanual chords and gestures were only faster in portrait mode. This can be attributable to the fact that there are shorter traversal distances for the single hand in landscape mode. All methods of evaluation used time trials and were thus quantitative and unbiased in nature. The most preferred method of human-computer interaction was the bimanual tap. In conclusion, bimanual maneuvers were overall faster than the single hand on a global scale.

Second, the researchers look to analyze the trade offs of the BiPad. They discovered that having the non-dominant hand on the same side is most efficient rather than on the opposite side or underneath the iPad device. Overall, bimanual taps were similar across the board for all holds and orientations. This was later confirmed for gestures and chords.

As far as comfort is concerned, taps were significantly the winner compared to gestures and chords. There were some abnormal positions for users such as applying a chord while holding the iPad from the top position. However, the unnatural state of the maneuver would not be executed in usage due to its awkward feel.

It should also be noted that the evaluation was systemically broken down as previously described. Instead of measuring the entire new design at one time, the researchers used separation of parts to measure each gesture in each mode with each holding position. This provided the most encompassing results.

Discussion:
In conclusion, not only was the bimanual implementation able to be cohesive with the iPad, but it did outperform the traditional one hand method in the timed trials. The breakthrough of the BiPad is that it lets users decide which hold, orientation, or gesture is most appropriate for their application as well as the one that adheres to there comfort levels. This proves to be useful for users that frequently change holds or ones who desire speed.

Overall, I thought the work was extremely intriguing and directly applicable to modern society. The speed up of iPad users would inherently be widespread due to the large volume of iPad owners. One of the most interesting aspects I enjoyed was that the analysis was conducted in both landscape and portrait mode. The work provided in this research is not ground breaking by any means. It will not drastically change the lifes of many, but it is some insightful work into improving modern technology. Although I would not consider this work eye popping, it was very interesting to read and will possibly show up in a future version of a touch pad.

 This enabled insights into different ways that different people access this type of technology. The evaluation itself was sound. They explored every possible hold, with every possible position, with every possible gesture. They did this independently to fully extract all results with no overlap. I would be curious about the correlation between comfort and speed of the device. Since users who tend to feel more comfortable will most likely perform faster, then this must be analyzed to properly evaluate the BiPad.