This is the presentation slides for our paper in WCRE 2012: Understanding Android Fragmentation with Topic Analysis of Vendor-Specific Bugs (http://webdocs.cs.ualberta.ca/~chenlei1/publication/Zhang-wcre-2012.pdf).

1. Understanding Android Fragmentation with Topic
Analysis of Vendor-Specific Bugs
Dan Han, Chenlei Zhang, Xiaochao Fan, Abram Hindle, Kenny Wong and Eleni Stroulia
Department of Computing Science
University of Alberta
1

2. • Introduction
• Previous Work
• Methodology
• Comparing Topic Models
• Fragmentation Topic Analysis
• Fragmentation Discussion
• Conclusion
Outline
2

3. • Introduction
• Previous Work
• Methodology
• Comparing Topic Models
• Fragmentation Topic Analysis
• Fragmentation Discussion
• Conclusion
Introduction
3

4. Hardware-Based Fragmentation
http://www.android.com/devices/?country=all

5. Software-Based Fragmentation
5
http://www.blackeco.com/petites-speculations-autour-de-la-prochaine-version-dandroid/

6. Why do we care
More than 20
Android device
manufacturers
Multiple Android versions
6
Hundreds of different
Android devices
Developers
Users
Stakeholders

7. What do we do in this study
7
 Goal: search for evidence of Android
fragmentation within Android ecosystem
based on the Android bug reports
 Approach: apply topic model and topic
analysis

8. • Introduction
• Previous Work
• Methodology
• Comparing Topic Models
• Fragmentation Topic Analysis
• Fragmentation Discussion
• Conclusion
Previous Work
8

9. Topic Model and Topic Analysis
9
Topic Model: a statistical model for discovering
abstract topics that occur in a collection of
documents.
 Latent Dirichlet Allocation (LDA)
Topic Analysis: extract and evaluate the
topics from a corpus of text documents through
topic models
 Traceability recovery: Asuncion et al., Lukins et al., Hindle et al.
 Feature location: Marcus et al., Poshyvanyk et al., Grant et al.
 Software evolution and trend analysis: Thomas et al., Martie et
al.

10. Differences between previous work and our work
10
 Previous work applied unsupervised topic
models, e.g. LDA
 We performed Labeled-LDA, a supervised
topic model to analyze topic evolution
 We compared the performance between
LDA and Labeled-LDA on our dataset

11. LDA and Labeled-LDA
11
Labeled-LDA
 A novel method applied in
software engineering so
far
 Manual labeling
 Supervised topic
modeling algorithm
 Labeled-LDA only
predicts the relevance
between each document
and its labels
LDA
 Well studied in software
engineering
 Unsupervised topic
modeling algorithm
 Need documents and
number of topics N as
input
 LDA predicts the
relevance between each
document and all the N
topics

12. Difference between a topic and a label
12
Topic:
 A word distribution extracted from bug
reports by topic models
Label:
 The annotation of a document

13. • Introduction
• Previous Work
• Methodology
• Comparing Topic Models
• Fragmentation Topic Analysis
• Fragmentation Discussion
• Conclusion
Methodology
13

14. Methodology
14

15. Case Study
15
 Android bug reports, 2008-2011, 20,000+
 Vendor-specific bug reports
 HTC -- 1503
 Motorola --1058
http://www.puremobile.co.uk/insiderblog/wp-
content/uploads/2011/08/Motorola-
Mobile_logo.jpg
http://www.finestdaily.com/news/htc-
jetstream-to-be-launched-on-september-
6t.html/attachment/htc_cmyk_white_strapl
ine
VS

16. Create labels for Android bug reports
16
 Feature-oriented labels for Android bug
reports
 Android labels
 Features in Android versions
e.g. Language, Bluetooth
 Popular applications
e.g. Google Maps, Gmail
 Hardware of Android devices
e.g. Keyboard, GPS

17. Label Android bug reports
17
 60 person-hours of manual labeling
effort
 Labeled bug reports are public now
HTC – 72 labels in total Motorola – 58 labels in total

18. Apply Labeled-LDA
18

19. Apply LDA
19
 Try a range of N to find the most distinct topics
 Label each topic using our manual labels for the
bug reports of HTC and Motorola
 2 hours of labeling effort

20. Comparing LDA and Labeled-LDA
20
 Each topic model generates the document-topic
matrix
 Determine if LDA generates similar results to
Labeled-LDA
 Compute and compare the Jaccard similarity of
documents related to each topic generated by
LDA and Labeled-LDA

21. • Introduction
• Previous Work
• Methodology
• Comparing Topic Models
• Fragmentation Topic Analysis
• Fragmentation Discussion
• Conclusion
Comparing Topic Models
21

22. Comparing Topic Models in HTC
22
Pairwise Jaccard Similarity between each topic in LDA and Labeled-LDA
Labeled-LDA
LDA

23. Diagonal Entries in HTC
23
Labeled-LDA
LDA

24. Comparing Topic Models in Motorola
24
Pairwise Jaccard Similarity between each topic in LDA and Labeled-LDA
LDA
Labeled-LDA

25. Conclusion of comparing LDA and Labeled-LDA
25
 Mean Jaccard similarities of the diagonal
entries are 0.2 for HTC and 0.08 for Motorola
 The number of bug reports related to same
labels in LDA and Labeled-LDA are different
( tests: p<0.01) for both HTC and Motorola
 Labeled-LDA produced more feature relevant
topics than LDA
2


26. • Introduction
• Previous Work
• Methodology
• Comparing Topic Models
• Fragmentation Topic Analysis
• Fragmentation Discussion
• Conclusion
Topic Analysis
26

27. Categorized Topics
27
Common Topics Unique Topics
Unique Topics
Common
Topics Unique Topics
HTC Motorola

28. Common Topics
28
Both vendors share many identical topic words
Label HTC Motorola
bluetooth bluetooth, headset, car,
connect, device,
connection, version,
data, app, desire, 2.2,
work, connects, behavior,
2.1
bluetooth, headset, droid,
device, connected,
connect, devices, calls,
car, issue, connection,
2.2, car, pair, time
Relevance of common topic “bluetooth” in HTC and Motorola
Android 2.1 Android 2.2

29. Common Topics
29
Topics of each vendor tend to have vendor-specific terms
Label HTC Motorola
display screen, version, desire,
behavior, app, home,
number, code, final,
press, sure, user, black,
new, power
droid, screen, button,
correct, home, display,
behavior, landscape, 2.1,
menu, bar, xoom, device,
user, status
http://www.motorola.com/xoomhttp://en.wikipedia.org/wiki/Motorol
a_droid
http://en.wikipedia.org/wiki/HTC
_Desire

30. Unique Topics in HTC
30
Label HTC Motorola
keyboard keyboard, input, text, key,
version, number, typing,
on-screen, mode, field,
landscape, virtual, keys,
type, message
keyboard, droid, keys,
text, press, space, box,
open, device, key, app,
software, 2.0.1,
landscape
Relevance of unique topic “keyboard” in HTC
Android 2.1Android 1.5

31. Unique Topics in Motorola
31
Label HTC Motorola
GPS gps, data, position,
location, maps, google,
time, lock, wrong, icon,
turn, home, latitude, unit,
tag, available
maps, gps, google, app,
droid, location,
application, navigation,
map, device, traffic, time,
upgrade, turn, route
Relevance of unique topic “GPS” in Motorola
Android 2.2

32. • Introduction
• Previous Work
• Methodology
• Comparing Topic Models
• Fragmentation Topic Analysis
• Fragmentation Discussion
• Conclusion
Discussion
32

33. Fragmentation Discussion
33
 Software-Based Fragmentation
 New features and changes contribute the bug reports
 Difficult to test across all of the vendor and product-lines
Relevance of common topic “bluetooth” in HTC and Motorola
Android 2.1 Android 2.2

34. Fragmentation Discussion
34
 Hardware-Based Fragmentation
 Different product lines were associated with different
topics
 Evident by differing bug topics and product specific issues
Label HTC Motorola
display screen, version, desire,
behavior, app, home,
number, code, final, press,
sure, user, black, new,
power
droid, screen, button,
correct, home, display,
behavior, landscape, 2.1,
menu, bar, xoom, device,
user, status

35. • Introduction
• Previous Work
• Methodology
• Comparing Topic Models
• Fragmentation Topic Analysis
• Fragmentation Discussion
• Conclusion
Conclusion
35

36. Conclusion
36
 Found how fragmentation is manifested within Android
between HTC and Motorola
 Incompatibility issues
 Portability issues
 Compared the performance of Labeled-LDA and LDA
 Labeled-LDA produced more feature relevant
topics than LDA
 Labeled-LDA need more manual effort
 http://softwareprocess.es/static/Fragmentation.html
(http://goo.gl/SwGDT)
 Could be useful to make project dashboards,
process mining and software process recovery