1. Mini-Me: An Adaptive Avatar for Mixed Reality Remote Collaboration
Piumsomboon, T., Lee, G. A., Hart, J. D., Ens, B., Lindeman, R. W., Thomas, B. H., & Billinghurst, M. 
University of South Australia, University of Canterbury
CHI 18’
Presented by: Ja Eun Yu

2. System Overview

3. Mini-Me Used in Mixed Reality (MR) remote collaboration.
Between a local Augmented Reality (AR) user and a remote Virtual Reality (VR) user.
AR User’s View
VR User’s View

4. Mini-Me An extension to the VR user’s life-size avatar
An adaptive avatar redirected gaze and gestures, designed to maintain nonverbal communication cues in a remote MR collaboration.

5. Implementation Environment: Unity3D AR: Microsoft HoloLens
VR: HTC Vive (HMD and room scale tracking system)
Synchronizing 2 spaces: Vuforia Image Target Technology

6. Purpose
Explore how adaptive avatars can improve Mixed Reality (MR) remote collaboration.
Improve the local AR user’s experience of collaborating with a remote VR user.
1. Overcome the limited FOV of the OST-HMD display.
2. Place the avatar at the appropriate position.
3. Redirect the avatar’s gaze and pointing naturally.

7. Novelty Concept, design, and implementation of the Mini-Me.
A novel adaptive avatar with redirected gaze and gesture for enhancing remote MR collaboration.
Findings from a user study, evaluating the impact of the Mini-Me on Social Presence, task difficulty, and mental effort for two collaborative scenarios.
Discussion of the implications for future MR collaborative interface design.

8. Research Design

9. conceptualization & research question
Social Presence
Co-Presence, Attentional Allocation, Perceived message understanding
Overall experience of MR collaboration (Usability)
Task Difficulty, Mental Effort, Enjoyment and Level of Focus, User Preference, Performance
Concepts
“How does Mini-Me affect the co-presence and overall user experience of MR collaboration?”

10. Operationalization Social Presence
Co-Presence, Attentional Allocation, Perceived message understanding
Ask users to rate/evaluate the social presence they feel.
Task difficulty, Mental Effort, Enjoyment and Level of Focus
Ask users to rate/evaluate the difficulty, mental effort, enjoyment and level of focus.
User Preference and subjective feedback
Ask users about their preferred condition and get a feedback.
Performance
Measure the amount of time users spent to complete each task.
- Subjective data
Usability
- Objective data

11. Metrics
Social Presence: Co-Presence, Attentional Allocation, Perceived message understanding
Questionnaire based on Networked Mind Measure of Social Presence (7-point Likert scale) - Interval
Task difficulty, Mental Effort, Enjoyment and Level of Focus
Single Ease Question (7-point Likert scale) - Interval
Subjective Mental Effort Question (0 ~ 150) - Interval
User Preference and subjective feedback
Post-task questionnaire after each scenario (preferred condition and the reason) - Ordinal
Performance
Task completion time (seconds) - Ratio

12. Variables Independent variables Presence of the Mini-Me avatar.
present (Mini-Me) and absent (Baseline).
Dependent variables
Co-Presence, Attentional Allocation, Perceived message understanding
Task Difficulty, Mental Effort, Enjoyment and Level of Focus, User Preference, Performance

13. Study Details

14. Setup 2 physically separated rooms. All trials are all recorded.
Furnished room for the local AR user
Empty room for the remote VR user
All trials are all recorded.
AR room was recorded by camera.
VR user’s view was screen recorded.
Furnished room
Reconstructed VR environment

15. Study design Baseline Condition Mini-Me condition
Only a life-size full-body avatar.
Ray is cast from the hand to the pointing target.
Additional Mini-Me avatar emerges when the user looks away from a life-size avatar.
A ray is cast from the Mini-Me avatar’s hand. VS
All the participants participated in the AR user role.
The VR user is an employed actor.
1 hour experiments.

16. Study design Cross-sectional / Controlled / Within-subject design
N = 16 (5 female)
Age: M = 28.44, SD = 5.766
To reduce the impact of novelty effect on the subjective ratings, recruited participants with some experience.
The tendency for performance to initially improve when new technology is instituted, in response to increased interest in the new technology.
To reduce the order effect, the order of the 2 conditions (Mini-Me and Baseline) were counter-balanced.

17. Tasks and procedures “Tea Party”
Asymmetric collaboration (AR local worker – VR remote helper).
AR user follows the VR user’s instruction for where to place tea boxes.
“Urban Planner”
Symmetric collaboration (equal role).
Placing 9 building on a street grid with given rules.
* To avoid a learning effect of the VR user, all the tasks are randomized.

18. Tasks and procedures Objective data (Task completion time)
*Only collected in the first part of the study
(time taken in 2nd scenario was primarily influenced by the participants’ level of experience in solving logic puzzle).
2 conditions x 3 trials per conditions x 16 participants = 96 data points
Subjective data
Post-task preference and overall feedback
2 conditions x 16 participants = 32 data points
Others
2 conditions x 2 tasks x16 participants = 64 data points
During the pilot tests, we found that time taken was primarily influenced by the participants’ level of experience in solving logic puzzle rather than the interface provided in each condition. We anticipated this, hence did not enforce any time constraint for this task. On average, the task took approximately five to ten minutes to complete.

19. Results: Objective Data (Task Completion time)
Non-Normal distribution (Shapiro-Wilk test)
Within-subject design
Wilcoxon signed rank test assumes that the measurements are continuous in theoretical nature.
Wilcoxon Signed Rank test
with continuity correction
Mini-Me took significantly less time to complete the task compared to Baseline
(V = 859, p=0.005).
< 0.05

20. Results: Subjective Data
Task Difficulty
Mental Effort
Enjoyment and
Level of Focus MM BL

21. Results: Subjective Data
Social Presence
Aggregated Social Presence Score
= Co-Presence + Attentional Allocation + Perceived Message Understanding
Cronbach’s Alpha
Cronbach's alpha is a measure used to assess the reliability, or internal consistency, of a set of scale or test items.

22. Results: Subjective Data
Social Presence (cont.)
Significant difference found for Co-Presence in Part 1.
Significant difference found for Co-Presence, Attentional Allocation and Perceived Message Understanding in Part 2.
Preference
Binominal test.
In case they answered no preference between the two condition, authors allocated them equally to each condition.

23. Results: Observation and Feedback
Pointing ray was very helpful.
Users liked the look and feel of the Mini-Me and the live-size avatar.
Users disliked the small FOV of the HoloLense.
Mini-Me improved users’ understanding of their partner.

24. Implications and Critique

25. Implications
Sharing non-verbal communication and awareness cues in collaborative MR systems improves user experiences.
The presence of the Mini-Me yielded a significantly higher Aggregated Social Presence Score for both asymmetric and symmetric collaboration, than the absence of such avatar.
The constant availability of remote pointing and awareness cues will likely reduce the task difficulty and mental effort, leading to improved performance time.

26. Critique Methodological strengths Methodological weakness
Clearly visualizing the questionnaire results.
Using Cronbach’s Alpha makes the analysis simpler.
Showing in detail where the Mini-me has strengths by using two separate tasks (symmetric / asymmetric)
Trying to reduce novelty, order, learning (VR user side) effects.
Methodological weakness
Subjective data (8) > Objective data (1)
No analysis on VR user side.
7 out of 16 analysis are not statistical significant.

27. Suggestion More objective metrics
Run the task within a limited amount of time, then measure the error rate.
Objectively measure the stress level: heart rate, EEG, etc.
Different Symmetric Collaboration task
Participants mentioned that they relied a lot more on verbal communication in this task and less on the non- verbal cues.

28. Discussion
Are there other objective metrics that are used in cases like this?
Several data points have a p-value under The study would have benefited from additional participants to increase statistical significance.
Is there a sort of equivalent representation used for quantitative data in other studies?
The fact that they used both symmetric and asymmetric collaboration condition might have been distracting.
More research on VR user side is necessary.

29. Thank you 