Post on 22-Jan-2017
Web Archive Profiling Through Fulltext Search
Sawood Alam and Michael L. NelsonComputer Science Department, Old Dominion University
Norfolk, Virginia - 23529
Herbert Van de SompelLos Alamos National Laboratory, Los Alamos, NM
David S. H. RosenthalStanford University Libraries, Stanford, CA
Supported in part by the IIPC and NSF 1526700
Unorganized Collections
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Organized Collections
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Collection Understanding
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Memento Aggregator
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Memento Aggregator
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Memento Aggregator
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Memento Aggregator
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Memento Aggregator
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Memento Aggregator
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From: Michael Nelson [mailto:mln@cs.odu.edu]
Sent: Wednesday, December 02, 2015 12:33 PM
To: Jones, Gina
Cc: Rourke, Patrick; Grotke, Abigail
Subject: Re: WebSciDL
Hi Gina, I'll investigate. memgator is software that one my students wrote, but I suspect the traffic you're seeing is b/c it is deployed in http://oldweb.today/ can you share the IP addr from where you're seeing the traffic? I presume the requests are for Memento TimeMaps? It should not being actually scraping HTML pages.
regards,
Michael
On Wed, 2 Dec 2015, Jones, Gina wrote:
> Hi Michael, we have a slight configuration issue with the current OW
> set up for our webarchives. I think, from looking at the logs, that
> "MemGator:1.0-rc3 <@WebSciDL>" is really causing some issues on our wayback.
> Do you know who is running this scraper? Itʼs not part of memento is it?
>
> Gina Jones
> Web Archiving Team
> Library of Congress
From: Ilya Kreymer <ikreymer@gmail.com>
Date: Wed, 2 Dec 2015 10:33:56 -0800
Subject: high traffic on oldweb!
To: Herbert Van de Sompel <hvdsomp@gmail.com>, Sawood Alam <ibnesayeed@gmail.com>
Hi Herbert, Sawood,
Herbert: Perhaps you are lucky that I am not using the LANL aggregator, as the traffic has gotten really high, and also I was asked to remove an archive due to the traffic it was causing temporarily..
I am thinking that ability to remove source archives quickly is an important aspect of an aggregator.
Sawood: Hopefully yours will support something like this so I don't need to restart the container to change the archivelist ;)
Ilya
Broadcasting is Bad
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Availability and Overlap
● Archives are sparse● Broadcasting is wasteful, both clients and archives suffer
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Memento Routing
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Routing Pros & Cons
● Pros○ Minimizes traffic and resources consumption○ Improves throughput
● Cons○ Upfront profile maintenance cost○ May miss Mementos (false negatives)
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Why Small Archives Matter?
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Why Small Archives Matter?
● 400B+ web pages at IA do not cover everything
● Top three archives after IA produce full TimeMap 52% of the time (AlSum, et al., TPDL 2013)
● Targeted crawls● Special focus archives● Restricted resources● Private archives● Censorship
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While the Internet Archive was Down...
$ memgator -f cdxj example.org | cut -c-4 | grep -v "^@" | uniq -c 2 2002 1 2005 1 2008 6 2009 67 2010 17 2011 64 2012 108 2013 108 2014 186 2015 51 2016 17
Archive Profile
● High-level summary of an archive● Predicts presence of mementos of a URI-R in
an archive● Provides various statistics about the holdings● Small in size● Publicly available● Easy to update and partially patch● Useful for Memento query routing and other
things
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Profiling Strategies
● Sample URI Profiling (AlSum, et al., TPDL 2013)
● CDX Profiling (Alam, et al., TPDL 2015)
● Response Cache Profiling (Bornand, et al., JCDL 2016)
● Fulltext Search Profiling
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Methodology
Top Nouns
timeyearpeoplewaymandaythingchildmrgovernment 20
Random Dict
analogiesunboltconsonantcoilsstolidlycigardecrepitrhododendroncannibalhoneydew
Dynamic Words Discovery
the وكالة warangry the أنباءarab العربي middlenews east الغاضبservice on arabica politics poetrysource war art
Random Searcher Model (RSM)
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START
STOP
Seed Vocabulary
NextWord()
ExtractWords()
Search()
Select a random link from the search results
Vocabulary seeding needed?
Termination condition reached?
GenerateProfile()
Store search results
No
Yes
YesNo
Fetch the contents of the selected document
RSM Illustration
Teaching Resources Adjunct Toolkit NC NET Academy PD Planning Tools Regional Centers Campus Liaisons Nontraditional Careers College Tech Prep NC ACCESS Co op Education Green Technology You are here NC NET Teaching Resources Discipline Specific English English Self Paced Modules Writing Across the Curriculum NC NET Western Center Incorporating Visuals in Workplace Documents Sections 1 2 Wake Tech Community College Incorporating Visuals in Workplace Documents Section 3 Wake Tech Community College All self paced modules can be accessed through the NC NET Blackboard server Log in with the user name faculty and the password nc net Once connected you can view the courses by topic or alphabetically by title English Webliography North Carolina Community College System 2012
RSM Modes
● Static: Externally supplied static word list● PopularityBiased: Refresh Vocabulary after
every search attempt and consider term frequency for selecting next search keyword
● EqualOpportunity: Refresh Vocabulary after every search attempt and ignore term frequency for selecting next search keyword
● Conservative: Discover new words only when the Vocabulary is exhausted
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Profiling Policies & Archive-It Dataset
Policy # Keys Example
URIR 30,800,406 uk,co,bbc,news,)/Images/Logo.png?height=80&width=200
HxP1 1,724,284 uk,co,bbc,news,)/Images
DDom 91,629 uk,co,bbc,)/
H1P0 212 uk,)/
Sample URI: https://www.news.BBC.co.uk/Images/Logo.png?width=80&height=40
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For a detailed list of profiling policies please refer to:Alam, et al.: Web Archive Profiling Through CDX Summarization. IJDL (2016) 17: 223-238
Searches vs Coverage
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100% in 11K searches
100% in 27K searches
100% in 337K searches 100% in 1.9M searches
RSM Operation Mode Costs
Mode Query Cost
HTTP Cost Remarks
Static C C Suitable for specialized collection with known top keywords
PopularityBiased C 2 * C Human like model, but costly
EqualOpportunity C 2 * C Human like model, but costly
Conservative C C + (where << C)
Suitable for any collection and works without any supplementary materials with very little overhead
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Routing Confusion Matrix
Predicted \ Actual Present in the Archive Not in the Archive
Routed to the Archive True Positive (TP) False Positive (FP)
Not Routed to the Archive False Negative (FN) True Negative (TN)
Routing Confusion Matrix Recall Accuracy27
Accuracy, Recall, & Coverage (10-100%)
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DMOZ IA Wayback
UK WaybackMemento Proxy
Low Accuracy (high FP) =>Archives & Aggregator suffer
Low Recall (high FN) =>Users suffer
Profile Policy Recommendations
● IF complete CDX is available THEN○ Generate HxP1 profile
● ELSE IF fulltext search is available THEN○ Generate DDom profile
● ELSE○ Generate H1P0 or other smaller profiles using
Sample URIs
Note: It is possible to perform less detailed queries on more specific (higher order) profiles, but not the other way
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RSM Mode Recommendations
● IF the collection is about a specific topic in a specific language AND a suitable top keywords list is available THEN○ Use Static mode
● ELSE○ Use Conservative mode
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Who Knows Term Frequency for Estonian Nouns?
31https://en.wiktionary.org/wiki/Category:Estonian_nouns
Future Work
● Evaluation of combination profiles such as URI-Key along with Datetime
● Utilize archive profile to generate rank ordered list of archive
● Profiles for usage other than Memento routing, such as, site classification based profiles (e.g., news, wiki, social media, blog etc.)
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Conclusions● Evaluated the search cost as a function of archive holdings’
coverage and profiling policy● Developed the Random Searcher Model● Correctly route 80% requests while maintaining 0.9 Recall
by only discovering 10% of the archive holdings and generating a profile that costs less than 1% of the complete knowledge profile
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