The Performance and Preference of Different Fingers and Chords for Pointing,
Dragging, and Object Transformation
Fingers and Technology
/
Goguey, Alix
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Nancel, Mathieu
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Casiez, Géry
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Vogel, Daniel
Proceedings of the ACM CHI'16 Conference on Human Factors in Computing
Systems
2016-05-07
v.1
p.4250-4261
© Copyright 2016 ACM
Summary: The development of robust methods to identify which finger is causing each
touch point, called "finger identification," will open up a new input space
where interaction designers can associate system actions to different fingers.
However, relatively little is known about the performance of specific fingers
as single touch points or when used together in a "chord." We present empirical
results for accuracy, throughput, and subjective preference gathered in five
experiments with 48 participants exploring all 10 fingers and 7 two-finger
chords. Based on these results, we develop design guidelines for reasonable
target sizes for specific fingers and two-finger chords, and a relative ranking
of the suitability of fingers and two-finger chords for common multi-touch
tasks. Our work contributes new knowledge regarding specific finger and chord
performance and can inform the design of future interaction techniques and
interfaces utilizing finger identification.
Finger-Aware Shortcuts
Fingers and Technology
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Zheng, Jingjie
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Vogel, Daniel
Proceedings of the ACM CHI'16 Conference on Human Factors in Computing
Systems
2016-05-07
v.1
p.4274-4285
© Copyright 2016 ACM
Summary: We evaluate and demonstrate finger, hand, and posture identification as
keyboard shortcuts. By detecting the hand and finger used to press a key, and
open or closed hand postures, a key press can have multiple command mappings. A
formative study reveals performance and preference patterns when using
different fingers and postures to press a key. The results are used to develop
a computer vision algorithm to identify fingers and hands on a keyboard
captured by a built-in lap top camera and reflector. This algorithm is built
into a background service to enable system-wide finger-aware shortcut keys in
any application. A controlled experiment uses the service to compare the
performance of Finger-Aware Shortcuts with existing methods. The results show
Finger-Aware Shortcuts are comparable with a common class of shortcuts using
multiple modifier keys. Finally, application demonstrations illustrate
different use cases and mappings for Finger-Aware Shortcuts and extend the idea
to two-handed key presses, continuous parameter control, and menu selection.
Doppio: A Reconfigurable Dual-Face Smartwatch for Tangible Interaction
Interaction with Small Displays
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Seyed, Teddy
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Yang, Xing-Dong
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Vogel, Daniel
Proceedings of the ACM CHI'16 Conference on Human Factors in Computing
Systems
2016-05-07
v.1
p.4675-4686
© Copyright 2016 ACM
Summary: Doppio is a reconfigurable smartwatch with two touch sensitive display
faces. The orientation of the top relative to the base and how the top is
attached to the base, creates a very large interaction space. We define and
enumerate possible configurations, transitions, and manipulations in this
space. Using a passive prototype, we conduct an exploratory study to probe how
people might use this style of smartwatch interaction. With an instrumented
prototype, we conduct a controlled experiment to evaluate the transition times
between configurations and subjective preferences. We use the combined results
of these two studies to generate a set of characteristics and design
considerations for applying this interaction space to smartwatch applications.
These considerations are illustrated with a proof-of-concept hardware prototype
demonstrating how Doppio interactions can be used for notifications, private
viewing, task switching, temporary information access, application launching,
application modes, input, and sharing the top.
Gunslinger: Subtle Arms-down Mid-air Interaction
Session 1B: Large Displays, Large Movements
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Liu, Mingyu
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Nancel, Mathieu
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Vogel, Daniel
Proceedings of the 2015 ACM Symposium on User Interface Software and
Technology
2015-11-05
v.1
p.63-71
© Copyright 2015 ACM
Summary: We describe Gunslinger, a mid-air interaction technique using barehand
postures and gestures. Unlike past work, we explore a relaxed arms-down
position with both hands interacting at the sides of the body. It features
"hand-cursor" feedback to communicate recognized hand posture, command mode and
tracking quality; and a simple, but flexible hand posture recognizer. Although
Gunslinger is suitable for many usage contexts, we focus on integrating mid-air
gestures with large display touch input. We show how the Gunslinger form factor
enables an interaction language that is equivalent, coherent, and compatible
with large display touch input. A four-part study evaluates Midas Touch,
posture recognition feedback, pointing and clicking, and general usability.
Pin-and-Cross: A Unimanual Multitouch Technique Combining Static Touches
with Crossing Selection
Session 5A: Touch Input
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Luo, Yuexing
/
Vogel, Daniel
Proceedings of the 2015 ACM Symposium on User Interface Software and
Technology
2015-11-05
v.1
p.323-332
© Copyright 2015 ACM
Summary: We define, explore, and demonstrate a new multitouch interaction space
called "pin-and-cross." It combines one or more static touches ("pins") with
another touch to cross a radial target, all performed with one hand. A
formative study reveals pin-and-cross kinematic characteristics and evaluates
fundamental performance and preference for target angles. These results are
used to form design guidelines and recognition heuristics for pin-and-cross
menus invoked with one and two pin fingers on first touch or after a drag.
These guidelines are used to implement different pin-and-cross techniques. A
controlled experiment compares a one finger pin-and-cross contextual menu to a
Marking Menu and partial Pie Menu: pin-and-cross is just as accurate and 27%
faster when invoked on a draggable object. A photo app demonstrates more
pin-and-cross variations for extending two-finger scrolling, selecting modes
while drawing, constraining two-finger transformations, and combining
pin-and-cross with a Marking Menu.
Usability and Security Perceptions of Implicit Authentication: Convenient,
Secure, Sometimes Annoying
Mobile Privacy and Security
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Khan, Hassan
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Hengartner, Urs
/
Vogel, Daniel
Proceedings of the 2015 Symposium on Usable Privacy and Security
2015-07-22
p.225-239
© Copyright 2015 Authors
Summary: Implicit authentication (IA) uses behavioural biometrics to provide
continuous authentication on smartphones. IA has been advocated as more usable
when compared to traditional explicit authentication schemes, albeit with some
security limitations. Consequently researchers have proposed that IA provides a
middle-ground for people who do not use traditional authentication due to its
usability limitations or as a second line of defence for users who already use
authentication. However, there is a lack of empirical evidence that establishes
the usability superiority of IA and its security perceptions. We report on the
first extensive two-part study (n = 37) consisting of a controlled lab
experiment and a field study to gain insights into usability and security
perceptions of IA. Our findings indicate that 91% of participants found IA to
be convenient (26% more than the explicit authentication schemes tested) and
81% perceived the provided level of protection to be satisfactory. While this
is encouraging, false rejects with IA were a source of annoyance for 35% of the
participants and false accepts and detection delay were prime security concerns
for 27% and 22% of the participants, respectively. We point out these and other
barriers to the adoption of IA and suggest directions to overcome them.
The performance of indirect foot pointing using discrete taps and kicks
while standing
Using your body
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Saunders, William
/
Vogel, Daniel
Proceedings of the 2015 Conference on Graphics Interface
2015-06-03
p.265-272
© Copyright 2015 ACM
Summary: We investigate the performance of indirect foot pointing while standing
using discrete taps and kicks. Two experiments show that left and right feet
perform at similar levels, there is little difference in selection time across
target configurations or directions, but targets with an angular size under
22.5° or radial size under 5cm should be avoided due to high error rates.
There is a detectable advantage to tapping compared to kicking, but little
practical difference. Although cursor feedback is optimal, we show that
eyes-free foot pointing achieves an error rate of 27% for 45° angular
targets. We translate our results into ten design guidelines and we illustrate
their application by designing foot interaction techniques to control desktop
applications at a standing desk.
Soft-Constraints to Reduce Legacy and Performance Bias to Elicit Whole-body
Gestures with Low Arm Fatigue
Gesture Elicitation & Recognition
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Ruiz, Jaime
/
Vogel, Daniel
Proceedings of the ACM CHI'15 Conference on Human Factors in Computing
Systems
2015-04-18
v.1
p.3347-3350
© Copyright 2015 ACM
Summary: Participant biases can influence proposed gestures in elicitation studies.
There is a legacy bias from previous experience with, or even knowledge of,
existing input devices, interfaces, and technologies. There is also a
performance bias, where the artificial study setting does not encourage
consideration of long-term aspects such as fatigue. These biases make it
especially difficult to uncover gestures appropriate for whole-body gestural
input. We propose using soft constraints to correct for legacy and performance
biases by penalizing physical movements. We use wrist weights as a soft
constraint to elicit whole-body gestures with low arm fatigue. We show soft
constraints encourage a wider range of gestures using subtler arm movements or
alternate body parts and lower consumed endurance for arm movements.
Myopoint: Pointing and Clicking Using Forearm Mounted Electromyography and
Inertial Motion Sensors
Mid-Air Gestures and Interaction
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Haque, Faizan
/
Nancel, Mathieu
/
Vogel, Daniel
Proceedings of the ACM CHI'15 Conference on Human Factors in Computing
Systems
2015-04-18
v.1
p.3653-3656
© Copyright 2015 ACM
Summary: We describe a mid-air, barehand pointing and clicking interaction technique
using electromyographic (EMG) and inertial measurement unit (IMU) input from a
consumer armband device. The technique uses enhanced pointer feedback to convey
state, a custom pointer acceleration function tuned for angular inertial
motion, and correction and filtering techniques to minimize side-effects when
combining EMG and IMU input. By replicating a previous large display study
using a motion capture pointing technique, we show the EMG and IMU technique is
only 430 to 790 ms slower and has acceptable error rates for targets greater
than 48 mm. Our work demonstrates that consumer-level EMG and IMU sensing is
practical for distant pointing and clicking on large displays.
Clutching Is Not (Necessarily) the Enemy
Interacting with GUIs
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Nancel, Mathieu
/
Vogel, Daniel
/
Lank, Edward
Proceedings of the ACM CHI'15 Conference on Human Factors in Computing
Systems
2015-04-18
v.1
p.4199-4202
© Copyright 2015 ACM
Summary: Clutching is usually assumed to be triggered by a lack of physical space and
detrimental to pointing performance. We conduct a controlled experiment using a
laptop trackpad where the effect of clutching on pointing performance is
dissociated from the effects of control-to-display transfer functions.
Participants performed a series of target acquisition tasks using typical
cursor acceleration functions with and without clutching. All pointing tasks
were feasible without clutching, but clutch-less movements were harder to
perform, caused more errors, required more preparation time, and were not
faster than clutch-enabled movements.
Adoiraccourcix: multi-touch command selection using finger identification
Techniques d'interaction: Commandes et Gestes
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Goguey, Alix
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Casiez, Géry
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Pietrzak, Thomas
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Vogel, Daniel
/
Roussel, Nicolas
Proceedings of the 2014 Conference of the Association Francophone
d'Interaction Homme-Machine
2014-10-28
p.28-37
© Copyright 2014 ACM
Summary: Hotkeys are a critical factor of performance for expert users in WIMP
interfaces. Multi-touch interfaces, by contrast, do not provide such efficient
command shortcuts. We propose Adoiraccourcix, which leverage finger
identification to introduce quick command invocation integrated with direct
manipulation in this context. After presenting the concept behind, we
illustrated Adoiraccourcix in a vectorial drawing application and ran
preliminary user studies comparing Adoiraccourcix to classical user interfaces.
Results suggest that once mastered, Adoiraccourcix provides very powerful means
of interaction.
Pinch-to-zoom-plus: an enhanced pinch-to-zoom that reduces clutching and
panning
Input techniques
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Avery, Jeff
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Choi, Mark
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Vogel, Daniel
/
Lank, Edward
Proceedings of the 2014 ACM Symposium on User Interface Software and
Technology
2014-10-05
v.1
p.595-604
© Copyright 2014 ACM
Summary: Despite its popularity, the classic pinch-to-zoom gesture used in modern
multi-touch interfaces has drawbacks: specifically, the need to support an
extended range of scales and the need to keep content within the view window on
the display can result in the need to clutch and pan. In two formative studies
of unimanual and bimanual pinch-to-zoom, we found patterns: zooming actions
follows a predictable ballistic velocity curve, and users tend to pan the
point-of-interest towards the center of the screen. We apply these results to
design an enhanced zooming technique called Pinch-to-Zoom-Plus (PZP) that
reduces clutching and panning operations compared to standard pinch-to-zoom
behaviour.
A three-step interaction pattern for improving discoverability in finger
identification techniques
Demonstrations
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Goguey, Alix
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Casiez, Géry
/
Vogel, Daniel
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Chevalier, Fanny
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Pietrzak, Thomas
/
Roussel, Nicolas
Adjunct Proceedings of the 2014 ACM Symposium on User Interface Software and
Technology
2014-10-05
v.2
p.33-34
© Copyright 2014 ACM
Summary: Identifying which fingers are in contact with a multi-touch surface provides
a very large input space that can be leveraged for command selection. However,
the numerous possibilities enabled by such vast space come at the cost of
discoverability. To alleviate this problem, we introduce a three-step
interaction pattern inspired by hotkeys that also supports feed-forward. We
illustrate this interaction with three applications allowing us to explore and
adapt it in different contexts.
Effect of Bezel Presence and Width on Visual Search
Papers Session #5
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Wallace, James R.
/
Vogel, Daniel
/
Lank, Edward
Proceedings of the 2014 ACM International Symposium on Pervasive Displays
2014-06-03
p.118-123
© Copyright 2014 ACM
Summary: We investigate how the presence and width of interior bezels impacts visual
search performance across tiled displays. In spite of a potential benefit from
structured segmentation, we do not find significant differences in visual
search time, and note a small effect size of less than 0.5% for bezel width.
However, we find participants are more accurate when searching for targets
spanning a bezel. Based on these findings, we suggest two implications for the
design of tiled displays: 1) that additional costs associated with thinner
bezels may not provide significant return on investment; and 2) that bezels may
act as visual anchors, and be useful for the placement of interface elements.
The effect of interior bezel presence and width on magnitude judgement
Understanding users: inking, perception and adaptation
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Wallace, James R.
/
Vogel, Daniel
/
Lank, Edward
Proceedings of the 2014 Conference on Graphics Interface
2014-05-07
p.175-182
© Copyright 2014 Springer International Publishing
Summary: Large displays are often constructed by tiling multiple small displays,
creating visual discontinuities from inner bezels that may affect human
perception of data. Our work investigates how bezels impact magnitude
judgement, a fundamental aspect of perception. Two studies are described which
control for bezel presence, bezel width, and user-to-display distance. Our
findings form three implications for the design of tiled displays. Bezels wider
than 0.5cm introduce a 4-7% increase in judgement error from a distance, which
we simplify to a 5% rule of thumb when assessing display hardware. Length
judgements made at arm's length are most affected by wider bezels, and are an
important use case to consider. At arm's length, bezel compensation techniques
provide a limited benefit in terms of judgement accuracy.
Crossing-based selection with direct touch input
Touch input
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Luo, Yuexing
/
Vogel, Daniel
Proceedings of ACM CHI 2014 Conference on Human Factors in Computing Systems
2014-04-26
v.1
p.2627-2636
© Copyright 2014 ACM
Summary: Fundamental performance results for crossing-based selection tasks with
direct touch input are presented. A close adaptation of Accot and Zhai's
indirect stylus crossing experiment reveals similar trends for direct touch
input: touch crossing task time is faster or equivalent to touch pointing;
continuous selection of large orthogonal crossing targets is most effective;
and continuous selection of small collinear targets is least effective. Unlike
indirect stylus and mouse crossing, not every kind of direct touch pointing
performance is modeled accurately with standard Fitts' law. Instead, Fitts'
law, used previously for touch pointing with small targets, is used to more
accurately model discrete touch crossing with a directionally constrained
target. In addition, visual touch feedback is shown to have a strong effect on
absolute accuracy. Our work empirically validates touch crossing as a practical
and efficient selection technique, and motivates the exploration of novel forms
of expressive multi-touch crossing.
Effects of information technologies, department characteristics and
individual roles on improving knowledge sharing visibility: a qualitative case
study
/
Zhang, Xi
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Vogel, Douglas R.
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Zhou, Zhongyun
Behaviour and Information Technology
2012-11
v.31
n.11
p.1117-1131
© Copyright 2012 Taylor and Francis Group, LLC
Summary: Knowledge sharing visibility (KSV) is a critical environmental factor which
can reduce social loafing in knowledge sharing (KS). This is especially true in
ICT-based KS in learning organisations. As such, it is imperative that we
better understand how to design technology enabled knowledge management systems
(KMS) to support high KSV. This article examines the impact of knowledge
management technology functions (e.g. tracking, knowledge storing) on KSV
through qualitative analysis of 16 semi-structured interviews with participants
in a Chinese company. Impact and implications of use for their existing KMS are
examined. This article also examined the effects of department characteristics
(i.e. group size and task characteristics) and individual roles (i.e. employee
positions) on the IT-KSV relationship. Results encourage applied statistical,
tracking, knowledge distribution and knowledge storing functions for monitoring
explicit KS, and suggest integration of visualised knowledge maps with
communication tools (e.g. Instant Messenger (IM)) to support visibility for
implicit KS. Findings also suggest that KM technologies are more salient on
improving KSV in large department with routine tasks, and that low-level
employees may have more positive attitude on accepting communication tools on
sharing knowledge. Extension to use of Web 2.0 technologies (e.g. weblogs) in
KMS is also explored.
Giving a hand to the eyes: leveraging input accuracy for subpixel
interaction
Interactions II
/
Roussel, Nicolas
/
Casiez, Géry
/
Aceituno, Jonathan
/
Vogel, Daniel
Proceedings of the 2012 ACM Symposium on User Interface Software and
Technology
2012-10-07
v.1
p.351-358
© Copyright 2012 ACM
Summary: We argue that the current practice of using integer positions for pointing
events artificially constrains human precision capabilities. The high
sensitivity of current input devices can be harnessed to enable precise direct
manipulation ""in between"" pixels, called subpixel interaction. We provide
detailed analysis of subpixel theory and implementation, including the critical
component of revised control-display gain transfer functions. A prototype
implementation is described with several illustrative examples. Guidelines for
subpixel domain applicability are provided and an overview of required changes
to operating systems and graphical user interface frameworks are discussed.
Territoriality and behaviour on and around large vertical publicly-shared
displays
Public displays
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Azad, Alec
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Ruiz, Jaime
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Vogel, Daniel
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Hancock, Mark
/
Lank, Edward
Proceedings of DIS'12: Designing Interactive Systems
2012-06-11
p.468-477
© Copyright 2012 ACM
Summary: We investigate behaviours on, and around, large vertical displays during
concurrent usage. Using an observational field study, we identify fundamental
patterns of how people use existing public displays: their orientation,
positioning, group identification, and behaviour within and between social
groups just-before, during, and just-after usage. These results are then used
to motivate a controlled experiment where two individuals or two pairs of
individuals complete tasks concurrently on a simulated large vertical display.
Results from our controlled study demonstrates that vertical surface
territories are similar to those found in horizontal tabletops in function, but
their definitions and social conventions are different. In addition, the nature
of use-while-standing systems results in more complex and dynamic physical
territories around the display. We show that the anthropological notion of
personal space must be slightly refined for application to vertical displays.
Hand occlusion on a multi-touch tabletop
Triple t: touch, tables, tablets
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Vogel, Daniel
/
Casiez, Géry
Proceedings of ACM CHI 2012 Conference on Human Factors in Computing Systems
2012-05-05
v.1
p.2307-2316
© Copyright 2012 ACM
Summary: We examine the shape of hand and forearm occlusion on a multi-touch table
for different touch contact types and tasks. Individuals have characteristic
occlusion shapes, but with commonalities across tasks, postures, and
handedness. Based on this, we create templates for designers to justify
occlusion-related decisions and we propose geometric models capturing the shape
of occlusion. A model using diffused illumination captures performed well when
augmented with a forearm rectangle, as did a modified circle and rectangle
model with ellipse "fingers" suitable when only X-Y contact positions are
available. Finally, we describe the corpus of detailed multi-touch input data
we generated which is available to the community.
1 € filter: a simple speed-based low-pass filter for noisy input in
interactive systems
Interactions beyond the desktop
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Casiez, Géry
/
Roussel, Nicolas
/
Vogel, Daniel
Proceedings of ACM CHI 2012 Conference on Human Factors in Computing Systems
2012-05-05
v.1
p.2527-2530
© Copyright 2012 ACM
Summary: The 1 € filter ("one Euro filter") is a simple algorithm to filter
noisy signals for high precision and responsiveness. It uses a first order
low-pass filter with an adaptive cutoff frequency: at low speeds, a low cutoff
stabilizes the signal by reducing jitter, but as speed increases, the cutoff is
increased to reduce lag. The algorithm is easy to implement, uses very few
resources, and with two easily understood parameters, it is easy to tune. In a
comparison with other filters, the 1 € filter has less lag using a
reference amount of jitter reduction.
Conté: multimodal input inspired by an artist's crayon
Tangible
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Vogel, Daniel
/
Casiez, Géry
Proceedings of the 201 ACM Symposium on User Interface Software and
Technology1
2011-10-16
v.1
p.357-366
© Copyright 2011 ACM
Summary: Conté is a small input device inspired by the way artists manipulate
a real Conté crayon. By changing which corner, edge, end, or side is
contacting the display, the operator can switch interaction modes using a
single hand. Conté's rectangular prism shape enables both precise
pen-like input and tangible handle interaction. Conté also has a natural
compatibility with multi-touch input: it can be tucked in the palm to
interleave same-hand touch input, or used to expand the vocabulary of bimanual
touch. Inspired by informal interviews with artists, we catalogue
Conté's characteristics, and use these to outline a design space. We
describe a prototype device using common materials and simple electronics. With
this device, we demonstrate interaction techniques in a test-bed drawing
application. Finally, we discuss alternate hardware designs and future human
factors research to study this new class of input.
Estimating the Perceived Difficulty of Pen Gestures
Human Factors I
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Vatavu, Radu-Daniel
/
Vogel, Daniel
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Casiez, Géry
/
Grisoni, Laurent
Proceedings of IFIP INTERACT'11: Human-Computer Interaction
2011-09-05
v.2
p.89-106
Keywords: gesture-based interfaces; pen input; gesture descriptors
© Copyright 2011 IFIP
Summary: Our empirical results show that users perceive the execution difficulty of
single stroke gestures consistently, and execution difficulty is highly
correlated with gesture production time. We use these results to design two
simple rules for estimating execution difficulty: establishing the relative
ranking of difficulty among multiple gestures; and classifying a single gesture
into five levels of difficulty. We confirm that the CLC model does not provide
an accurate prediction of production time magnitude, and instead show that a
reasonably accurate estimate can be calculated using only a few gesture
execution samples from a few people. Using this estimated production time, our
rules, on average, rank gesture difficulty with 90% accuracy and rate gesture
difficulty with 75% accuracy. Designers can use our results to choose
application gestures, and researchers can build on our analysis in other
gesture domains and for modeling gesture performance.
Occlusion-aware interfaces
Interfaces and visualization
/
Vogel, Daniel
/
Balakrishnan, Ravin
Proceedings of ACM CHI 2010 Conference on Human Factors in Computing Systems
2010-04-10
v.1
p.263-272
Keywords: Occlusion, hand, image processing, pen
© Copyright 2010 ACM
Summary: We define occlusion-aware interfaces as interaction techniques which know
what area of the display is currently occluded, and use this knowledge to
counteract potential problems and/or utilize the hidden area. As a case study,
we describe the Occlusion-Aware Viewer, which identifies important regions
hidden beneath the hand and displays them in a non-occluded area using a
bubble-like callout. To determine what is important, we use an application
agnostic image processing layer. For the occluded area, we use a user
configurable, real-time version of Vogel et al.'s [21] geometric model. In an
evaluation with a simultaneous monitoring task, we find the technique can
successfully mitigate the effects of occlusion, although issues with ambiguity
and stability suggest further refinements. Finally, we present designs for
three other occlusion-aware techniques for pop-ups, dragging, and a hidden
widget.
Direct Pen Interaction With a Conventional Graphical User Interface
/
Vogel, Daniel
/
Balakrishnan, Ravin
Human-Computer Interaction
2010
v.25
n.4
p.324-388
© Copyright 2010 Taylor and Francis
Summary: We examine the usability and performance of Tablet PC direct pen input with
a conventional graphical user interface (GUI). We use a qualitative
observational study design with 16 participants divided into 4 groups: 1 mouse
group for a baseline control and 3 Tablet PC groups recruited according to
their level of experience. The study uses a scripted scenario of realistic
tasks and popular office applications designed to exercise standard GUI
components and cover typical interactions such as parameter selection, object
manipulation, text selection, and ink annotation. We capture a rich set of
logging data including 3D motion capture, video taken from the participants'
point-of-view, screen capture video, and pen events such as movement and taps.
To synchronize, segment, and annotate these logs, we used our own custom
analysis software.
We find that pen participants make more errors, perform inefficient
movements, and express frustration during many tasks. Our observations reveal
overarching problems with direct pen input: poor precision when tapping and
dragging, errors caused by hand occlusion, instability and fatigue due to
ergonomics and reach, cognitive differences between pen and mouse usage, and
frustration due to limited input capabilities. We believe these to be the
primary causes of nontext errors, which contribute to user frustration when
using a pen with a conventional GUI. Finally, we discuss how researchers could
address these issues without sacrificing the consistency of current GUIs and
applications by making improvements at three levels: hardware, base
interaction, and widget behavior.
