WEB ARCHIVE
SERVICES FRAMEWORK
FOR TIGHTER INTEGRATION
BETWEEN THE PASTAND PRESENT WEB
Ahmed AlSum
PhD Defense
February 20...
Domain
Contribution
Goal
WEB ARCHIVE
SERVICES FRAMEWORK
FOR TIGHTER INTEGRATION
BETWEEN THE PASTAND PRESENT WEB
Ahmed AlSu...
Outline
• Introduction
• Web Archiving Services Framework
• Content Service
• Metadata Service
• URI Service
• Archive Ser...
INTRODUCTION
Motivation and Research Questions
4
What is a Web Archive?
Introduction  Motivation
http://www.cs.odu.edu
5
Who are using Web Archives? & How?
• Politicians
• Journalists
• Web designers
• Historians
• Researchers
• Social scienti...
Web Archives interfaces are limited
Introduction  Motivation
7
Web Archiving Use Cases
• Ponguru asked on Internet Archive forum on May 17,
2010*:
• Hi All - I am new to Archive.org. A ...
Lack of APIs
• Famous websites provide APIs to the third-party
developer.
Introduction  Motivation
9
Limited and non-standards APIs
• Current Web Archives have a limited set of APIs that don‟t
cover the user‟s needs.
Introd...
Wayback Machine API
Introduction  Motivation
• It returns JSON
interface for the list of
available Mementos.
11
Croatian Web Archive
Introduction  Motivation
Full-text search web interface Full-text search APIs in JSON
12
Memento
Introduction  Motivation
• Memento provides
TimeMap in the
application CoRE
format.
13
Memento Terminology
Introduction  Motivation
URI-R, R
URI-M, M
URI-T, TM
http://www.amazon.com
http://web.archive.org/web...
Memento Aggregator
• Merges TimeMaps from various archives.
Introduction  Motivation
15
Web Archiving as Big Data
• Internet Archive corpus reached 5 PetaBytes.
• Alexandria Bibliotheca needs one year to recomp...
Research Question
How Can We Enrich The Web Archive Access
Interface With The Conjunction Of The Live Web?
Introduction  ...
Research Questions
• What are the required services for the web archiving user
community?
• Shall we work on the web archi...
WEB ARCHIVE
SERVICE FRAMEWORK
Levels and Datasets
19
Web Archive Service Framework
Web Archive Service Framework
20
• Archive level
• Web Archive profiling to
optimize the query routing.
• URI level
• URI HTTP redirection in the
web archi...
IIPC 2010 Winter Olympics
Web Archive Service Framework  Datasets
* http://olympics.us.archive.org/olympics2010/
Size 700...
Fortune 500
• 499,540 mementos from 488
TimeMaps.
• For each Memento, we download the
HTML and capture the thumbnail using...
DMOZ
Web Archive Service Framework  Datasets
• URI Open Directory
based on user
submissions.
24
CONTENT SERVICE
ArcContent
25
Archive
URI
Metadata
Content
Wayback Machine URI Rewriting
Original Rewritten
Content Service
26
Response Types
Raw Response
Modified Response
Extracted Response
Content Service
27
ArcContent Architecture Diagram
Content Service
28
Extracted Response Filters
Content Service
TextContent
TFContent
29
Extracted Response Formats
Content Service
XML
JSON
30
ArcContent Applications
Content Service
TFContent
TagClouds
31
METADATA SERVICE
ArcLink & ArcThumb
32
Archive
URI
Metadata
Content
Metadata Access Service
Metadata Service
• Metadata is data about data.
• Metadata layer is data about mementos.
Type Fiel...
ArcLink
Motivation, Stages, Cost Model, Applications
34
ArcLink: optimization
techniques to build and
retrieve the temporal web
graph
A. AlSum and M. L. Nelson,.
In Proceedings o...
Easily Solved Questions
Q: What are the available mementos for
www.vancouver2010.com?
Metadata Service  ArcLink  Motivat...
Solved Questions, but hard
Q. What are the HTML titles for www.vancouver2010.com
through time?
A. Page scraping for all me...
Impossible Questions
Q What are the anchor-text that pointed to
www.vancouver2010.com through time?
Metadata Service  Arc...
Outlinks
Metadata Service  ArcLink  Motivation
39
ArcLink and Temporal Web Graph
What is ArcLink?
• ArcLink is a complete system to Extract, Preserve, and
Access to Tempora...
System Stages
Metadata Service  ArcLink  Stages
41
Filtering
• Using CDX files to filter the URI to select the mementos
that will contribute to the Web Graph.
• For example,...
Extraction
• Technique: Hadoop
• Step 1: URI-ID generation
• Canonicalized the URI into SURT format
• Hash the canonicaliz...
Storage
• ArcLink used database to save the web
graph
Metadata Service  ArcLink  Stages
Insertion Performance Update Per...
ArcLink Response
Metadata Service  ArcLink  Stages
45
ArcLink Response
Metadata Service  ArcLink  Stages
46
ArcLink Response
Metadata Service  ArcLink  Stages
47
Impossible Questions
Q. What are the anchor-text that pointed to
www.vancouver2010.com through time?
Metadata Service  Ar...
Temporal Page Rank
Nov-2009 Dec-2009 Jan-2010
1 vancouver2010.com/code - topsport.com/sportch/liveticker/
2 vancouver2010....
ArcThumb
Motivation, Feature Exploration, Selection Algorithm
50
Thumbnail Summarization
Techniques For Web
Archives
AlSum and M. L. Nelson,.
In Proceedings of the 36th European Conferenc...
Thumbnails in Web Archive
Metadata Service  ArcThumb  Motivation
Internet Archive UK Web Archive
52
Thumbnails Creation Challenges
• Scalability in Time
• IA may need 361 years to create thumbnail for each memento
using on...
Thumbnails Usage Challenges
54
Metadata Service  ArcThumb  Motivation
• This is partial view of 700 thumbnails out of 10...
From 10,500 Mementos to 69 Thumbnails.
Metadata Service  ArcThumb  Motivation
55
How many thumbnails do we need?
Metadata Service  ArcThumb  Methodology
www.unfi.com on the live Web
56
How many thumbnails do we need?
Metadata Service  ArcThumb  Methodology
www.unfi.com on the live Web
57
40 Thumbnails are good.
Metadata Service  ArcThumb  Methodology
58
Visual Similarity and Text Similarity
Metadata Service  ArcThumb  Methodology
SimilarDifferent
HTML Text
59
Correlation between
Visual Similarity and Text Similarity
Metadata Service  ArcThumb  Feature Exploration
SimHash DOM tr...
Threshold Grouping
Metadata Service  ArcThumb  Selection Algorithms
61
Threshold Grouping
Metadata Service  ArcThumb  Selection Algorithms
62
Clustering technique
Metadata Service  ArcThumb  Selection Algorithms
SimHash Feature SimHash and Datetime Features
63
P...
Time Normalization
Metadata Service  ArcThumb  Selection Algorithms
64
Selection Algorithms Comparison
Threshold Grouping K clustering Time Normalization
TimeMap Reduction 27% 9% to 12% 23%
Ima...
URI SERVICE
66
Archive
URI
Metadata
Content
ARCHIVAL HTTP
REDIRECTION RETRIEVAL
POLICIES
A. AlSum, M. L. Nelson, R. Sanderson, and H. Van de Sompel
In Proceedings of ...
Live Web Redirect
http://bit.ly/r9kIfC redirects to http://www.cs.odu.edu
URI Service
% curl -I http://bit.ly/r9kIfC
HTTP/...
Live Web Redirect
URI Service
R http://bit.ly/r9kIfC R http://www.cs.odu.edu
redirects to
69
R1 www.draculathemusical.co.uk R2 www.mosaicstudio.co.uk
R1
http://web.archive.org/web/20020212194020/http://www.draculath...
Experiment
• Dataset: 10,000 sample URIs from
• Dataset does not include bit.ly nor doi.
• Experiment focused on the root ...
URI Stability
• URI‟s stability is a count of the change in HTTP responses
across time (200, 3xx, or 4xx) and the number o...
Abstract Model
•
URI Service
M1 M2 M3
73
Timemap Redirection Categories
URI Service
All Mementos have 200 HTTP status code All Mementos have redirection to the sam...
URI Stability
URI Service  Experiment and Results
TimeMap Category Percentage Stability
All Mementos have OK 52% 1
Mement...
Current Wayback Machine Policy
•
URI Service  Retrieval Policies
76
Policy one:
URI-R with HTTP redirection
•
URI Service  Retrieval Policies
Retrieve the memento M for R.
Status(M) =200
St...
Policy one:
URI-R with HTTP redirection
• Evaluation:
• Policy scope has: 1471 URIs (that have live redirection)
• 77 out ...
Policy two:
URI-M with HTTP redirection
•
URI Service  Retrieval Policies
http://www.cnn.com/
Accept-Datetime: Sun, 13 Ma...
Policy two:
URI-M with HTTP redirection
• Evaluation:
• Policy scope: 2980 TimeMap (that showed HTTP redirection status co...
ARCHIVE SERVICE
Percentage and Distribution
81
Archive
URI
Metadata
Content
How Much Of The Web Is
Archived?
S. G. Ainsworth, A. AlSum, H. SalahEldeen, M. C. Weigle, and M. L. Nelson
In Proceedings ...
Experiment
• 4 Sample sets – 1000 URIs each
• For each URI, we used Memento Aggregator to record the
TimeMap for this URI....
Archives Under Experiment
2010 2010 and 2013 2013
Archive Service  Percentage  Experiment
U
K
84
How Much of the Web is Archived?
• It Depends on Which Web…
Archive Service  Percentage  Results
2010 2013
Including
SE ...
Profiling Web Archive
Coverage For
Top-level Domain And
Content Language
A. AlSum, M. C. Weigle, M. L. Nelson, and H. Van ...
Memento Aggregator
Archive Service  Distribution
87
Where can you find?
Archive Service  Distribution
http://www.google.com/
88
Where can you find?
Archive Service  Distribution
http://www.google.com/
89
Where can you find?
Archive Service  Distribution
http://www.japantimes.co.jp/
90
Where can you find?
Archive Service  Distribution
http://www.japantimes.co.jp/
91
Research Question
Problem
• We need to profile the web archives around the world with
these characteristics:
• Age
• Top-l...
URIs Samples Sources
Archive Service  Distribution
Web
1. DMOZ – Random sample
2. DMOZ – TLD 200 URIs for
each TLD from D...
TLD Coverage
Archive Service  Distribution
IA Internet Archive AIT Archive It LoC Library of Congress UK UK National Libr...
Language Coverage
Archive Service  Distribution
IA Internet Archive CAN Library and Archives Canada PO Portuguese Web Arc...
Growth Rate
Archive Service  Distribution
IA Internet Archive CAN Library and Archives Canada PO Portuguese Web Archive C...
Building Web Archive Profile
Archive Service  Distribution
97
• RecallTM@1 = 3/8 = 0.375
• RecallTM@2 = 5/8 = 0.625
Web Archive Selection Evaluation
Archive Service  Distribution
TM(R...
Web Archive Selection Evaluation
Archive Service  Distribution
Number of Archive Including IA Excluding IA
RecallTM@3 0.9...
CONCLUSIONS
100
Conclusions
• We proposed a new service framework that divides the web archive
corpus into four levels: Content, Metadata,...
Publications
• S. G. Ainsworth, A. AlSum, H. SalahEldeen, M. C. Weigle, and M. L. Nelson. “How
much of the Web is Archived...
What‟s next?
• Web Archiving Engineer at Stanford University.
103
WEB ARCHIVE
SERVICES FRAMEWORK
FOR TIGHTER INTEGRATION
BETWEEN THE PASTAND PRESENT WEB
Ahmed AlSum
PhD Defense
February 20...
BACKUP
105
Memento
• Memento is an HTTP
extension to integrate the
Past and the Current
Web
I Jacobs and N Walsh Architecture of the ...
Memento
• Developer and administrator for Memento aggregator and proxies
107
Memento Clients
• Memento currently is RFC.
108
Lack of APIs
• Famous websites provide APIs to the third-party
developer.
Introduction  Motivation
109
Lack of APIs
• US Agencies started to support APIs to data access.
Introduction  Motivation
110
Web Archiving Use Cases
• Temporal navigation.
• Full text search.
• Use language filters.
• Provide raw WARC.
• Import of...
Related Projects
Data analysis for the web data
Tools and Methods to access the web archive
Enable the user to do experime...
Selection
• Decide what to capture
Everything, any domain
National domains
Delegate selection to partners
Users‟ favorites...
URI-Based
WayBack Machine
Web Archiving Trends  Accessing Web Archive
• Textbox to enter the
requested URI.
• BubbleMap t...
Collection-Based
Web Archiving Trends  Accessing Web Archive
• In addition to
browsing the
collection, you can
browse the...
Full-text search
Web Archiving Trends  Accessing Web Archive
• BL interface provides
different filtering
techniques for t...
Past Web Browser
Web Archiving Trends  Accessing Web Archive
• You can replay the
pages with different
controls to forwar...
Zoetrope
Web Archiving Trends  Accessing Web Archive
• Different Views
• Comparison between
different Mementos
• Not feas...
DiffIE
Web Archiving Trends  Accessing Web Archive
• A browser plug-in that
caches the pages a
person visits and
highligh...
Synchronicity
Web Archiving Trends  Accessing Web Archive
• Mozilla Firefox add-on
supports internet user
in (re-)discove...
Warrick
Web Archiving Trends  Accessing Web Archive
• It’s a utility for
reconstructing or
recovering a website
when a ba...
ArcSys Architecture Diagram
Web Archive Service Framework
122
WAT files
• WAT files are metadata files for WARC files
• WAT files are used to create data analysis reports based
on larg...
It‟s More than WAT files
WAT ArcLink
Batch Process on a set of WARCs Batch process on a set of URIs
For internal use For p...
Cost of Scaling Up
•
Metadata Service  ArcLink  Cost model
Internet
Archive
88 hrs
108 * 109 mementos
247 days
500 TB
Fi...
Time-Indexed Inlinks Information
Metadata Service  ArcLink  Applications
Date Anchor Text
04-Nov-09 vancouver2010.com
11...
HTTP Redirection Relationship
between URI-R & URI-M
URI Service  Experiment and Results
Live Web URI − R
OK Redirection
W...
Timemap Redirection Categories
• Category 1
URI Service
All Mementos have 200 HTTP status code
128
Timemap Redirection Categories
• Category 2
URI Service
All Mementos have redirection to the same URI.
129
Timemap Redirection Categories
• Category 3
URI Service
All Mementos have redirection to different URIs.
130
Timemap Redirection Categories
• Category 4
URI Service
Mementos have different HTTP status code.
131
HTTP Redirection Relationship
between URI-R & URI-M
URI Service
Live Web URI − R
OK Redirection
Web Archive
URI-M
OK Case ...
URI Reliability
•
URI Service
M1
3xx
M2
3xx
M3
3xx
rel=original
R`M
rel=original
R`M
rel=original
R`M
? ? ?200 404 3xx
133
Summary
• Quantitative study with 10,000 URIs.
• 48% were not fully stable through time.
• 27% were not perfectly reliable...
URI Reliability
• 23% of the mementos did not lead to a successful
memento at the end.
URI Service  Experiment and Result...
Experiment
Archive Service  Percentage  Experiment
• For each sample set, we used Memento
Aggregator to get all the poss...
1000 URIs Ordered by First Observation Date
Archive Service  Percentage  Results
See also: http://ws-dl.blogspot.com/201...
2010
Archive Service  Percentage  Results
2013
138
Archive Service  Percentage  Results
2010 2013
139
Archive Service  Percentage  Results
2010 2013
140
Archive Service  Percentage  Results
2010 2013
141
URIs Samples Sources –
Live Web
1. DMOZ – Random sample
• 10,000 URIs randomly sample from DMOZ directory (~5M URIs).
2. D...
URIs Samples Sources –
Web Archive
• Query the fulltext search interface for the web archives
with two set of query terms....
URIs Samples Sources –
User requests
• Sampling from the users requests to the web archived
materials
6. Sample from IA Wa...
General Coverage
Archive Service  Distribution
IA Internet Archive AIT Archive It LoC Library of Congress UK UK National ...
Web Archive Selection Evaluation
Archive Service  Distribution
146
Web Archive Selection Evaluation
Archive Service  Distribution
147
Future Works
148
iTunes cover application
Metadata Service  ArcThumb  Motivation
149
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  • "Web Archive services framework for tighter integration between the past and the present web", Phd defense presentation.

    1. 1. WEB ARCHIVE SERVICES FRAMEWORK FOR TIGHTER INTEGRATION BETWEEN THE PASTAND PRESENT WEB Ahmed AlSum PhD Defense February 2014 Committee Members: • Michael L. Nelson • Michele C. Weigle • Hussein M. Abdel-Wahab • M‟Hammad Abdous • Herbert Van de Sompel Old Dominion University Computer Science Department 1
    2. 2. Domain Contribution Goal WEB ARCHIVE SERVICES FRAMEWORK FOR TIGHTER INTEGRATION BETWEEN THE PASTAND PRESENT WEB Ahmed AlSum PhD Defense February 2014 Committee Members: • Michael L. Nelson • Michele C. Weigle • Hussein M. Abdel-Wahab • M‟Hammad Abdous • Herbert Van de Sompel Old Dominion University Computer Science Department 2
    3. 3. Outline • Introduction • Web Archiving Services Framework • Content Service • Metadata Service • URI Service • Archive Service • Conclusions 3
    4. 4. INTRODUCTION Motivation and Research Questions 4
    5. 5. What is a Web Archive? Introduction  Motivation http://www.cs.odu.edu 5
    6. 6. Who are using Web Archives? & How? • Politicians • Journalists • Web designers • Historians • Researchers • Social scientists • Curious users Introduction  Motivation 6 *IIPC Access Working Group 2006, Costa 2010, Dougherty 2010, Stirling 2011, Smith 2009
    7. 7. Web Archives interfaces are limited Introduction  Motivation 7
    8. 8. Web Archiving Use Cases • Ponguru asked on Internet Archive forum on May 17, 2010*: • Hi All - I am new to Archive.org. A few quick questions (1) Is there any API or tools available to access the Archive.org contents programmatically? (2) Are there any research papers where Archive.org was used for data collection / analysis (e.g. studying a particular topic over time, etc.)? I digged a little bit, could not find much, so checking with the group. " Introduction  Motivation *http://archive.org/post/306799/api-or-tools-to-access-research-publications-on-archiveorg 8
    9. 9. Lack of APIs • Famous websites provide APIs to the third-party developer. Introduction  Motivation 9
    10. 10. Limited and non-standards APIs • Current Web Archives have a limited set of APIs that don‟t cover the user‟s needs. Introduction  Motivation 10
    11. 11. Wayback Machine API Introduction  Motivation • It returns JSON interface for the list of available Mementos. 11
    12. 12. Croatian Web Archive Introduction  Motivation Full-text search web interface Full-text search APIs in JSON 12
    13. 13. Memento Introduction  Motivation • Memento provides TimeMap in the application CoRE format. 13
    14. 14. Memento Terminology Introduction  Motivation URI-R, R URI-M, M URI-T, TM http://www.amazon.com http://web.archive.org/web/20110411070244/http://amazon.com Original Resource Memento TimeMap 14 Van de Sompel, H., Nelson, M. L., & Sanderson, R. (2013). RFC 7089 - HTTP framework for time-based access to resource states -- Memento. Internet Engineering Task Force (IETF). Retrieved from http://tools.ietf.org/html/rfc7089
    15. 15. Memento Aggregator • Merges TimeMaps from various archives. Introduction  Motivation 15
    16. 16. Web Archiving as Big Data • Internet Archive corpus reached 5 PetaBytes. • Alexandria Bibliotheca needs one year to recompute checksum for its corpus. • Tools Introduction  Motivation Apache Pig 16
    17. 17. Research Question How Can We Enrich The Web Archive Access Interface With The Conjunction Of The Live Web? Introduction  Research Questions 17
    18. 18. Research Questions • What are the required services for the web archiving user community? • Shall we work on the web archive collection as one entity or on different levels? • How can we use the web archive content beyond full-text search? • What are the metadata fields that could enhance user browsing? • How can we develop access interface to the temporal web graph? • How can we optimize creation of thumbnails? • How can we use the HTTP redirection to enhance the URI- lookup query? • How can we optimize the query routing mechanism across the web archives? Introduction  Research Questions 18
    19. 19. WEB ARCHIVE SERVICE FRAMEWORK Levels and Datasets 19
    20. 20. Web Archive Service Framework Web Archive Service Framework 20
    21. 21. • Archive level • Web Archive profiling to optimize the query routing. • URI level • URI HTTP redirection in the web archive URI-lookup. • Metadata level • ArcLink • ArcThumb • Content level • ArcContent Web Archive Service Framework ArcSys 21
    22. 22. IIPC 2010 Winter Olympics Web Archive Service Framework  Datasets * http://olympics.us.archive.org/olympics2010/ Size 700+GB From Nov 2009 To Mar 2010 #URI-R 6.4M #URI-M 23.7M 22
    23. 23. Fortune 500 • 499,540 mementos from 488 TimeMaps. • For each Memento, we download the HTML and capture the thumbnail using PhantomJS. Web Archive Service Framework  Datasets 23
    24. 24. DMOZ Web Archive Service Framework  Datasets • URI Open Directory based on user submissions. 24
    25. 25. CONTENT SERVICE ArcContent 25 Archive URI Metadata Content
    26. 26. Wayback Machine URI Rewriting Original Rewritten Content Service 26
    27. 27. Response Types Raw Response Modified Response Extracted Response Content Service 27
    28. 28. ArcContent Architecture Diagram Content Service 28
    29. 29. Extracted Response Filters Content Service TextContent TFContent 29
    30. 30. Extracted Response Formats Content Service XML JSON 30
    31. 31. ArcContent Applications Content Service TFContent TagClouds 31
    32. 32. METADATA SERVICE ArcLink & ArcThumb 32 Archive URI Metadata Content
    33. 33. Metadata Access Service Metadata Service • Metadata is data about data. • Metadata layer is data about mementos. Type Field Description Example Technical Content-type Entity mimetype. text/html Content-length Size of the entity-body. 90883 Extracted Title Title of the page. Egypt rejoices at Mubarak departure Description Description about the content of the entity-body. The BBC World Affairs Editor John Simpson reflects on how Egypt brought about the overthrow of President Hosni Mubarak. Outgoing Links A list of all the outlinks that the page pointed to. Derived Thumbnail Thumbnail of the representation of the web page. Incoming Links A list of all the inlinks that to pointed to the page 33
    34. 34. ArcLink Motivation, Stages, Cost Model, Applications 34
    35. 35. ArcLink: optimization techniques to build and retrieve the temporal web graph A. AlSum and M. L. Nelson,. In Proceedings of the 13th annual international ACM/IEEE joint conference on Digital libraries JCDL „13, Indianapolis, Indiana, 2013 See also: http://arxiv.org/abs/1305.5959 35
    36. 36. Easily Solved Questions Q: What are the available mementos for www.vancouver2010.com? Metadata Service  ArcLink  Motivation 36
    37. 37. Solved Questions, but hard Q. What are the HTML titles for www.vancouver2010.com through time? A. Page scraping for all mementos Metadata Service  ArcLink  Motivation 37
    38. 38. Impossible Questions Q What are the anchor-text that pointed to www.vancouver2010.com through time? Metadata Service  ArcLink  Motivation … <a href=www.vancouver2010.com > Vancouver Olympics </a> …. … <a href=www.vancouver2010.com > Winter Olympics </a> … … <a href=www.vancouver2010.com > Vancouver 2010 </a> … 38
    39. 39. Outlinks Metadata Service  ArcLink  Motivation 39
    40. 40. ArcLink and Temporal Web Graph What is ArcLink? • ArcLink is a complete system to Extract, Preserve, and Access to Temporal Web Graph. What is the Temporal Web Graph? • Link structure through the time, including inlinks and outlinks. Metadata Service  ArcLink  Motivation WG @t2WG @t1 TWG 40
    41. 41. System Stages Metadata Service  ArcLink  Stages 41
    42. 42. Filtering • Using CDX files to filter the URI to select the mementos that will contribute to the Web Graph. • For example, • Exclude non-200 HTTP status code • Exclude Images, style-sheets, videos, etc • Exclude duplicate mementos • Technique: Using Pig Latin script on CDX files • Results: CDX was reduced to 25% of the original size, from 23.8M mementos to 6.7M mementos. Metadata Service  ArcLink  Stages 42
    43. 43. Extraction • Technique: Hadoop • Step 1: URI-ID generation • Canonicalized the URI into SURT format • Hash the canonicalized format using SimHash • Completely distributed • Step 2: Define data sources Metadata Service  ArcLink  Stages Input Source Map (sec) Reduce (sec) Total (sec) 2 Tasks Wayback 21,422 4,194 25,616 WARC 13,327 2,770 16,098 (62%) 5 Tasks Wayback 13,721 2,257 15,978 WARC 8,304 1,746 10,051 (62%) • WARC • Web archive UI 43
    44. 44. Storage • ArcLink used database to save the web graph Metadata Service  ArcLink  Stages Insertion Performance Update Performance 44
    45. 45. ArcLink Response Metadata Service  ArcLink  Stages 45
    46. 46. ArcLink Response Metadata Service  ArcLink  Stages 46
    47. 47. ArcLink Response Metadata Service  ArcLink  Stages 47
    48. 48. Impossible Questions Q. What are the anchor-text that pointed to www.vancouver2010.com through time? Metadata Service  ArcLink  Applications 48
    49. 49. Temporal Page Rank Nov-2009 Dec-2009 Jan-2010 1 vancouver2010.com/code - topsport.com/sportch/liveticker/ 2 vancouver2010.com/en/langpolicy - vancouver2010.com/code 3 vancouver2010.com/forgotpassword - canadacode.vancouver2010.com/ user/register 4 vancouver2010.com/store - canadacode.vancouver2010.com 5 vancouver2010.com/store/index.html - canadacode.vancouver2010.com/explore 6 vancouver2010.com/ - canadacode.vancouver2010.com/ user/login?destination=node/add/image 7 canadacode.vancouver2010.com - canadacode.vancouver2010.com/pulse 8 canadacode.vancouver2010.com/nfb-onf - canadacode.vancouver2010.com/challenge 9 canadacode.vancouver2010.com/contact - i-credible.nl 10 canadacode.vancouver2010.com/resources - vpzschaatsteam.nl Metadata Service  ArcLink  Applications Feb-2010 Mar-2010 Collection ( Nov-09 to Mar-10 ) 1 monlibe.liberation.fr monlibe.liberation.fr monlibe.liberation.fr 2 topsport.com/sportch/liveticker/ laprovence.com/la-provence-le-faq-de-la- moderation vancouver2010.com/code 3 lefigaro.fr get.adobe.com/flashplayer lefigaro.fr 4 laprovence.com/la-provence-le-faq-de-la- moderation vancouver2010.teamgb.com /teamgb/team- behind-team-gb/filenotfound.aspx laprovence.com/la-provence-le-faq-de- la-moderation 5 lefigaro.fr/sport ledauphine.com lefigaro.fr/sport 6 get.adobe.com/flashplayer lefigaro.fr/economie get.adobe.com/flashplayer 7 lefigaro.fr/meteo lefigaro.fr/sport lefigaro.fr/meteo 8 lefigaro.fr/le-talk lefigaro.fr/actualites-a-la-une lefigaro.fr/le-talk 9 dosb.de/de/vancouver-2010/vancouver- ticker/detail/printer.html lemonde.fr/cgv topsport.com/sportch/liveticker/ 10 ledauphine.com ffs.fr/index.php vancouver2010.com/en/langpolicy 49
    50. 50. ArcThumb Motivation, Feature Exploration, Selection Algorithm 50
    51. 51. Thumbnail Summarization Techniques For Web Archives AlSum and M. L. Nelson,. In Proceedings of the 36th European Conference on Information Retrieval. ECIR 2014, Amsterdam, Netherlands, 2014 51
    52. 52. Thumbnails in Web Archive Metadata Service  ArcThumb  Motivation Internet Archive UK Web Archive 52
    53. 53. Thumbnails Creation Challenges • Scalability in Time • IA may need 361 years to create thumbnail for each memento using one hundred machines. • Scalability in Space • IA will need 355 TB to store 1 thumbnail per each memento. • Page quality Metadata Service  ArcThumb  Motivation 53
    54. 54. Thumbnails Usage Challenges 54 Metadata Service  ArcThumb  Motivation • This is partial view of 700 thumbnails out of 10,500 available mementos for www.apple.com
    55. 55. From 10,500 Mementos to 69 Thumbnails. Metadata Service  ArcThumb  Motivation 55
    56. 56. How many thumbnails do we need? Metadata Service  ArcThumb  Methodology www.unfi.com on the live Web 56
    57. 57. How many thumbnails do we need? Metadata Service  ArcThumb  Methodology www.unfi.com on the live Web 57
    58. 58. 40 Thumbnails are good. Metadata Service  ArcThumb  Methodology 58
    59. 59. Visual Similarity and Text Similarity Metadata Service  ArcThumb  Methodology SimilarDifferent HTML Text 59
    60. 60. Correlation between Visual Similarity and Text Similarity Metadata Service  ArcThumb  Feature Exploration SimHash DOM tree Embedded resources Memento Datetime 60 SimHash [Charikar 2002], DOM tree [Pawlik 2011], Memento Datetime [Van de Sompel 2013]
    61. 61. Threshold Grouping Metadata Service  ArcThumb  Selection Algorithms 61
    62. 62. Threshold Grouping Metadata Service  ArcThumb  Selection Algorithms 62
    63. 63. Clustering technique Metadata Service  ArcThumb  Selection Algorithms SimHash Feature SimHash and Datetime Features 63 Park, H.-S., & Jun, C.-H. (2009). A simple and fast algorithm for K-medoids clustering. Expert Systems with Applications, 36(2, Part 2), 3336–3341.
    64. 64. Time Normalization Metadata Service  ArcThumb  Selection Algorithms 64
    65. 65. Selection Algorithms Comparison Threshold Grouping K clustering Time Normalization TimeMap Reduction 27% 9% to 12% 23% Image Loss 28 78 - 101 109 # Features 1 feature 1 or more 1 feature Preprocessing required Yes Yes No Efficient processing Medium Extensive Light Incremental Yes No Yes Online/offline Both Both Both Metadata Service  ArcThumb  Selection Algorithms 65
    66. 66. URI SERVICE 66 Archive URI Metadata Content
    67. 67. ARCHIVAL HTTP REDIRECTION RETRIEVAL POLICIES A. AlSum, M. L. Nelson, R. Sanderson, and H. Van de Sompel In Proceedings of 3rd Temporal Web Analytics Workshop. TempWeb 2013, Rio de Janeiro, Brazil 67
    68. 68. Live Web Redirect http://bit.ly/r9kIfC redirects to http://www.cs.odu.edu URI Service % curl -I http://bit.ly/r9kIfC HTTP/1.1 301 Moved …. Location: http://www.cs.odu.edu/ … 68
    69. 69. Live Web Redirect URI Service R http://bit.ly/r9kIfC R http://www.cs.odu.edu redirects to 69
    70. 70. R1 www.draculathemusical.co.uk R2 www.mosaicstudio.co.uk R1 http://web.archive.org/web/20020212194020/http://www.draculathemusical.co.uk/ R3 http://web.archive.org/web/20020212194020/http://www.geocities.com/draculathemusical WebArchiveLiveweb redirects to redirects to has Memento Archived Web Redirect URI Service 70
    71. 71. Experiment • Dataset: 10,000 sample URIs from • Dataset does not include bit.ly nor doi. • Experiment focused on the root page (no embedded resources) URI Service  Experiment and Results HTTP Status/Code (10,000 URI-R) OK (200) 82.83% Redirection (3xx) 14.71% Redirection (301) 8.4% Redirection (302) 6.1% Redirection (others) 0.2% Not-Found (4xx) 1.18% Others 1.28% HTTP Status/Code (894,717 URI-M) OK (200) 93.46% Redirection (3xx) 5.69% Not-Found (4xx) 0.26% Others 0.59% URIs Live HTTP status code Memento HTTP status code 71
    72. 72. URI Stability • URI‟s stability is a count of the change in HTTP responses across time (200, 3xx, or 4xx) and the number of different URIs in the “Location” for 3xx status code. High Stability = 1 No Stability = 0 URI Service 72
    73. 73. Abstract Model • URI Service M1 M2 M3 73
    74. 74. Timemap Redirection Categories URI Service All Mementos have 200 HTTP status code All Mementos have redirection to the same URI. All Mementos have redirection to different URIs. Mementos have different HTTP status code. 74
    75. 75. URI Stability URI Service  Experiment and Results TimeMap Category Percentage Stability All Mementos have OK 52% 1 Mementos have mixed status codes 36% 0.91 All Mementos have Redirection 0.92% 0.85 Redirection to the same URI 0.62% Redirection to different URIs 0.30% URI has no Mementos at all 10.97% 0 Stability in semi-log scale Stability for |TM(R)| < 300 75
    76. 76. Current Wayback Machine Policy • URI Service  Retrieval Policies 76
    77. 77. Policy one: URI-R with HTTP redirection • URI Service  Retrieval Policies Retrieve the memento M for R. Status(M) =200 Status(M) =3xx Stop Go to Policy 2 Stop Yes Yes Yes No No No 77
    78. 78. Policy one: URI-R with HTTP redirection • Evaluation: • Policy scope has: 1471 URIs (that have live redirection) • 77 out of 1471 have no mementos at all • 17 out of 77 have been retrieved mementos based on live redirection URI Service  Retrieval Policies 78
    79. 79. Policy two: URI-M with HTTP redirection • URI Service  Retrieval Policies http://www.cnn.com/ Accept-Datetime: Sun, 13 May 2006 http://www.cnn.com/ 79
    80. 80. Policy two: URI-M with HTTP redirection • Evaluation: • Policy scope: 2980 TimeMap (that showed HTTP redirection status code in at least one memento) • Success criteria: Using policy two contributed to the original TimeMap • Success percentage: 58% of the cases URI Service  Retrieval Policies 80
    81. 81. ARCHIVE SERVICE Percentage and Distribution 81 Archive URI Metadata Content
    82. 82. How Much Of The Web Is Archived? S. G. Ainsworth, A. AlSum, H. SalahEldeen, M. C. Weigle, and M. L. Nelson In Proceedings of the 11th annual international ACM/IEEE joint conference on Digital libraries JCDL '11, Ottawa, Canada 2011 See also: http://arxiv.org/abs/1212.6177 82
    83. 83. Experiment • 4 Sample sets – 1000 URIs each • For each URI, we used Memento Aggregator to record the TimeMap for this URI. Archive Service  Percentage  Experiment 83
    84. 84. Archives Under Experiment 2010 2010 and 2013 2013 Archive Service  Percentage  Experiment U K 84
    85. 85. How Much of the Web is Archived? • It Depends on Which Web… Archive Service  Percentage  Results 2010 2013 Including SE cache Excluding SE Cache General 90% 79% 90% 97% 68% 95% 88% 19% 52% 35% 16% 33% 85
    86. 86. Profiling Web Archive Coverage For Top-level Domain And Content Language A. AlSum, M. C. Weigle, M. L. Nelson, and H. Van de Sompel In Proceedings of the 17th International Conference on Theory and Practice of Digital Libraries TPDL 2013, Valletta, Malta, 2013 Extended version is invited to special edition in IJDL. See also: http://arxiv.org/abs/1309.4008 86
    87. 87. Memento Aggregator Archive Service  Distribution 87
    88. 88. Where can you find? Archive Service  Distribution http://www.google.com/ 88
    89. 89. Where can you find? Archive Service  Distribution http://www.google.com/ 89
    90. 90. Where can you find? Archive Service  Distribution http://www.japantimes.co.jp/ 90
    91. 91. Where can you find? Archive Service  Distribution http://www.japantimes.co.jp/ 91
    92. 92. Research Question Problem • We need to profile the web archives around the world with these characteristics: • Age • Top-level domains • Languages • Growth rate Goal • To optimize the query routing for Memento Aggregator. • To determine the missing parts of the web. Archive Service  Distribution 92
    93. 93. URIs Samples Sources Archive Service  Distribution Web 1. DMOZ – Random sample 2. DMOZ – TLD 200 URIs for each TLD from DMOZ (80 tlds) 3. DMOZ – Languages 100 URIs for each Languages (40 lang.) Web Archives 4. Top 1-Gram from Bing 5. Top 1000 queries term by Yahoo in 9 languages User requests 6. IA Wayback Machine log files 7. Memento aggregator log files * We used hostnames only 93
    94. 94. TLD Coverage Archive Service  Distribution IA Internet Archive AIT Archive It LoC Library of Congress UK UK National Library BL British Library SG Singapore CAT Web Archive of Catalonia CR Croatian Web Archive CZ Archive of the Czech Web TW National Taiwan University IC Icelandic Web Archive CAN Library and Archives Canada SI Slovenia WEB Web Cite AIS Archive.is 94
    95. 95. Language Coverage Archive Service  Distribution IA Internet Archive CAN Library and Archives Canada PO Portuguese Web Archive CZ Archive of the Czech Web LoC Library of Congress BL British Library CAT Web Archive of Catalonia TW National Taiwan University IC Icelandic Web Archive UK UK National Library CR Croatian Web Archive AIT Archive It IA Internet Archive AIT Archive It LoC Library of Congress UK UK National Library BL British Library SG Singapore CAT Web Archive of Catalonia CR Croatian Web Archive CZ Archive of the Czech Web TW National Taiwan University IC Icelandic Web Archive CAN Library and Archives Canada SI Slovenia WEB Web Cite AIS Archive.is 95
    96. 96. Growth Rate Archive Service  Distribution IA Internet Archive CAN Library and Archives Canada PO Portuguese Web Archive CZ Archive of the Czech Web LoC Library of Congress BL British Library CAT Web Archive of Catalonia TW National Taiwan University IC Icelandic Web Archive UK UK National Library CR Croatian Web Archive AIT Archive It Stopped archiving in 2008 Steady growth Stopped getting new URIs, but still crawling IA Internet Archive AIT Archive It LoC Library of Congress UK UK National Library BL British Library SG Singapore CAT Web Archive of Catalonia CR Croatian Web Archive CZ Archive of the Czech Web TW National Taiwan University IC Icelandic Web Archive CAN Library and Archives Canada SI Slovenia WEB Web Cite AIS Archive.is 96
    97. 97. Building Web Archive Profile Archive Service  Distribution 97
    98. 98. • RecallTM@1 = 3/8 = 0.375 • RecallTM@2 = 5/8 = 0.625 Web Archive Selection Evaluation Archive Service  Distribution TM(R) A1 M1 M2 M3 A2 M4 M5 A3 M6 A4 M7 A5 M8 98
    99. 99. Web Archive Selection Evaluation Archive Service  Distribution Number of Archive Including IA Excluding IA RecallTM@3 0.96 0.647 RecallTM@6 0.98 0.83 RecallTM@9 0.998 0.983 RecallTM@12 0.999 0.987 • Total number of archives N = 15 99
    100. 100. CONCLUSIONS 100
    101. 101. Conclusions • We proposed a new service framework that divides the web archive corpus into four levels: Content, Metadata, URI, and Archive. • The development of ArcContent that supports the web archive interface with extracted version of the mementos based on a set of predefined filters. • We studied the challenges of building the temporal web graph and developed ArcLink, a distributed system to extract, preserve, and expose the temporal web graph. • We studied the optimization and summarization techniques to create the thumbnails for the web graph collections based on SimHash fingerprints. • We extended the concept of URI-lookup in the web archive to include the HTTP redirection status code. • The concept of “Web Archive Profile” to characterize the web archive corpus was defined with an application on the distributed search in the Memento Aggregator. 101
    102. 102. Publications • S. G. Ainsworth, A. AlSum, H. SalahEldeen, M. C. Weigle, and M. L. Nelson. “How much of the Web is Archived?” In Proceedings of the 11th annual international ACM/IEEE joint conference on Digital libraries, JCDL '11, 2011. • A. AlSum, M. L. Nelson, R. Sanderson, and H. Van de Sompel. “Archival HTTP Redirection Retrieval Policies.” In Proceedings of 3rd Temporal Web Analytics Workshop, TempWeb ‟13, 2013. • A. AlSum, and M. L. Nelson. “ArcLink: Optimization Techniques to Build and Retrieve the Temporal Web Graph.” In Proceedings of the 13th annual international ACM/IEEE joint conference on Digital libraries, JCDL '13, 2013. • A. AlSum, Michele C. Weigle, M. L. Nelson, and H. Van de Sompel. “Profiling Web Archive Coverage for Top-Level Domain and Content Language.” In Proceedings of the 17th International Conference on Theory and Practice of Digital Libraries, TPDL 2013, 2013. • A. AlSum, and M. L. Nelson. “Thumbnail Summarization Techniques for Web Archives.” In Proceedings of the 36th European Conference on Information Retrieval. ECIR „14, 2014. 102
    103. 103. What‟s next? • Web Archiving Engineer at Stanford University. 103
    104. 104. WEB ARCHIVE SERVICES FRAMEWORK FOR TIGHTER INTEGRATION BETWEEN THE PASTAND PRESENT WEB Ahmed AlSum PhD Defense February 2014 Old Dominion University Computer Science Department 104 @aalsum
    105. 105. BACKUP 105
    106. 106. Memento • Memento is an HTTP extension to integrate the Past and the Current Web I Jacobs and N Walsh Architecture of the world wide web Technical report, W3C, 2004 http://wwww3org/TR/webarch/ Now T1 T2 T3 106
    107. 107. Memento • Developer and administrator for Memento aggregator and proxies 107
    108. 108. Memento Clients • Memento currently is RFC. 108
    109. 109. Lack of APIs • Famous websites provide APIs to the third-party developer. Introduction  Motivation 109
    110. 110. Lack of APIs • US Agencies started to support APIs to data access. Introduction  Motivation 110
    111. 111. Web Archiving Use Cases • Temporal navigation. • Full text search. • Use language filters. • Provide raw WARC. • Import of metadata records into other repositories. Introduction  Motivation *IIPC Access Working Group. Use cases for Access to Internet Archives. International Internet Preservation Consortium Publications, http://www.netpreserve.org/resources/use-cases-access-internet-archives, 2006. 111
    112. 112. Related Projects Data analysis for the web data Tools and Methods to access the web archive Enable the user to do experiments on the raw crawled data on Amazon S3 Enable the user to browse the present and the past web Introduction 112
    113. 113. Selection • Decide what to capture Everything, any domain National domains Delegate selection to partners Users‟ favorites • We studied what is already captured 113
    114. 114. URI-Based WayBack Machine Web Archiving Trends  Accessing Web Archive • Textbox to enter the requested URI. • BubbleMap to show you the available mementos. 114
    115. 115. Collection-Based Web Archiving Trends  Accessing Web Archive • In addition to browsing the collection, you can browse the URIs in this collection. 115
    116. 116. Full-text search Web Archiving Trends  Accessing Web Archive • BL interface provides different filtering techniques for the results. 116
    117. 117. Past Web Browser Web Archiving Trends  Accessing Web Archive • You can replay the pages with different controls to forward, backward, pause and stop. 117
    118. 118. Zoetrope Web Archiving Trends  Accessing Web Archive • Different Views • Comparison between different Mementos • Not feasible on the current web archiving infrastructure 118
    119. 119. DiffIE Web Archiving Trends  Accessing Web Archive • A browser plug-in that caches the pages a person visits and highlights how those pages have changed when the person returns to them • It is possible on the personal archiving. 119
    120. 120. Synchronicity Web Archiving Trends  Accessing Web Archive • Mozilla Firefox add-on supports internet user in (re-)discovering missing web pages in real time 120
    121. 121. Warrick Web Archiving Trends  Accessing Web Archive • It’s a utility for reconstructing or recovering a website when a back-up is not available 121
    122. 122. ArcSys Architecture Diagram Web Archive Service Framework 122
    123. 123. WAT files • WAT files are metadata files for WARC files • WAT files are used to create data analysis reports based on large datasets. Metadata Service 123
    124. 124. It‟s More than WAT files WAT ArcLink Batch Process on a set of WARCs Batch process on a set of URIs For internal use For public use No-way to integerate with others WAT files in others locations It could be aggregated with other graphs No incremental update Support incremental update Access on WAT file level using Pig Access on URI level using Web service Metadata Service  ArcLink  Motivation 124
    125. 125. Cost of Scaling Up • Metadata Service  ArcLink  Cost model Internet Archive 88 hrs 108 * 109 mementos 247 days 500 TB Filtering Extraction Storage *Numbers based on Wayback Machine published statistics on Oct 2013 of 360B mementos with total size 5PB 125
    126. 126. Time-Indexed Inlinks Information Metadata Service  ArcLink  Applications Date Anchor Text 04-Nov-09 vancouver2010.com 11-Nov-09 vancouver2010.com 18-Nov-09 vancouver2010.com 16-Jan-10 Vancouver 2010 Olympic Games 16-Jan-10 Vancouver 2010 Olympic Games 23-Jan-10 vancouver2010.com 23-Jan-10 2010 Vancouver Olympic Games Medals Results Schedule Sports 30-Jan-10 2010 Vancouver Olympic Games Medals Results Schedule Sports 30-Jan-10 vancouver2010.com 30-Jan-10 Vancouver 2010 Olympic Games 13-Feb-10 Vancouver 2010 Olympic Winter Games 15-Feb-10 Vancouver 2010 Olympic Games 18-Feb-10 Official Vancouver Games site 19-Feb-10 vancouver2010.com 20-Feb-10 Official Vancouver Games site 21-Feb-10 VANOC 2010 126
    127. 127. HTTP Redirection Relationship between URI-R & URI-M URI Service  Experiment and Results Live Web URI − R OK Redirection Web Archive URI-M OK Case 1 5 Redirection 2 3,4 Case 1 Case 2 Case 3 Case 4 Case 5 80.8% 2.74% 1.34% 1.33% 13.7% 127
    128. 128. Timemap Redirection Categories • Category 1 URI Service All Mementos have 200 HTTP status code 128
    129. 129. Timemap Redirection Categories • Category 2 URI Service All Mementos have redirection to the same URI. 129
    130. 130. Timemap Redirection Categories • Category 3 URI Service All Mementos have redirection to different URIs. 130
    131. 131. Timemap Redirection Categories • Category 4 URI Service Mementos have different HTTP status code. 131
    132. 132. HTTP Redirection Relationship between URI-R & URI-M URI Service Live Web URI − R OK Redirection Web Archive URI-M OK Case 1 5 Redirection 2 3,4 Case 1 Case 2 Case 3 Case 4 Case 5 132
    133. 133. URI Reliability • URI Service M1 3xx M2 3xx M3 3xx rel=original R`M rel=original R`M rel=original R`M ? ? ?200 404 3xx 133
    134. 134. Summary • Quantitative study with 10,000 URIs. • 48% were not fully stable through time. • 27% were not perfectly reliable through time. • New archival retrieval policy: • Policy one: successfully retrieved mementos for 17 out of 77. • Policy two: Expanded the TimeMap for 58% of cases. URI Service  Retrieval Policies 134
    135. 135. URI Reliability • 23% of the mementos did not lead to a successful memento at the end. URI Service  Experiment and Results Reliabilityin semi-log scale Reliabilityfor |TM(R)| < 300 135
    136. 136. Experiment Archive Service  Percentage  Experiment • For each sample set, we used Memento Aggregator to get all the possible archived copies (Mementos). • For each URI, Memento Aggregator responded with TimeMap for this URI. Example <http://memento.waybackmachine.org/memento/2001081919423 3/http://jcdl2002.org>;rel="first memento";datetime="Sun, 19 Aug 2001 19:42:33 GMT“, <http://memento.waybackmachine.org/memento/2001121622024 8/http://jcdl2002.org>; rel="memento"; datetime="Sun, 16 Dec 2001 22:02:48 GMT", 136
    137. 137. 1000 URIs Ordered by First Observation Date Archive Service  Percentage  Results See also: http://ws-dl.blogspot.com/2011/06/2011-06-23-how-much-of-web-is-archived.html 137
    138. 138. 2010 Archive Service  Percentage  Results 2013 138
    139. 139. Archive Service  Percentage  Results 2010 2013 139
    140. 140. Archive Service  Percentage  Results 2010 2013 140
    141. 141. Archive Service  Percentage  Results 2010 2013 141
    142. 142. URIs Samples Sources – Live Web 1. DMOZ – Random sample • 10,000 URIs randomly sample from DMOZ directory (~5M URIs). 2. DMOZ – TLD: 200 URIs for each TLD • 80 tlds. 3. DMOZ – Languages 100 URIs for each Languages • 40 languages. Archive Service  Distribution 142
    143. 143. URIs Samples Sources – Web Archive • Query the fulltext search interface for the web archives with two set of query terms. 4. Top 1-Gram from Bing • Most of them is English 5. Top 1000 queries term by Yahoo in 9 languages • We excluded the general keywords such as: Obama, Facebook. Archive Service  Distribution 143
    144. 144. URIs Samples Sources – User requests • Sampling from the users requests to the web archived materials 6. Sample from IA Wayback Machine Log files • 10,000 URIs randomly sampled from Feb 22, 2012 to Feb 26, 2012. 7. Sample from Memento aggregator log files • 1,000 URIs randomly sampled from LANL Memento Aggregator between 2011 to 2013. Archive Service  Distribution 144
    145. 145. General Coverage Archive Service  Distribution IA Internet Archive AIT Archive It LoC Library of Congress UK UK National Library BL British Library SG Singapore CAT Web Archive of Catalonia CR Croatian Web Archive CZ Archive of the Czech Web TW National Taiwan University IC Icelandic Web Archive CAN Library and Archives Canada SI Slovenia WEB Web Cite AIS Archive.is 145
    146. 146. Web Archive Selection Evaluation Archive Service  Distribution 146
    147. 147. Web Archive Selection Evaluation Archive Service  Distribution 147
    148. 148. Future Works 148
    149. 149. iTunes cover application Metadata Service  ArcThumb  Motivation 149

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