P2PediaA Distributed Wiki

Network Management and Artificial Intelligence Laboratory

Carleton University

Presented by: Alexander CraigMay 9th, 2011

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Overview

What is a Wiki? Distributed vs. Centralized Wikis Article Versioning Model What is P2Pedia? Versioning Path Queries and Wiki Links

Trust Indicators

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What is a Wiki? “the simplest online database that could

possibly work” - Ward Cunningham

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What is a Wiki? Wikis are edited through a web based

interface using a simple markup language

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What is a Wiki?

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Distributed vs. Centralized Wikis

Traditional wiki systems, such as Wikipedia, use a centralized architecture where all content is stored on a central server.

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Distributed vs. Centralized Wikis

In a distributed wiki system, every user of the system acts as a host, and shares a portion of the wiki data set.

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Advantages of Distributed Wikis

Reliability - No centralized point of failure Scalability - Distributed bandwidth usage

and costs No centralized authority to censor content Offline operation – Users can retain read

and edit access to all locally stored data even in the case of a network failure

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Versioning Model

In a traditional, centralized wiki versioning is strictly linear.

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Versioning Model In a distributed system, articles may be

modified concurrently by separate authors on separate nodes.

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Distributed Wikis – Existing Work

Existing work largely aims to present a logically centralized service over a distributed architecture.

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Versioning Model

Distributed modifications result in a tree of article versions, rather than a linear sequence

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Versioning Model

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Versioning Model

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Versioning Model: Future Work

P2Pedia also aims to support user assisted merging of articles. In this case, a lattice of article versions may be formed.

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Versioning Model This distributed versioning model reflects

the underlying peer to peer infrastructure of the system, and may be better suited to some domains (ex: teaching materials).

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What is P2Pedia? A distributed wiki system implemented

using the community customization options provided by the Universal Peer to Peer framework

Articles are stored in an XML format, and use the Creole wiki markup open standard

CREOLE – A common wiki markup

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P2Pedia

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P2Pedia

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P2Pedia

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Versioning Queries Complex queries can be performed on the

version graph using the provided graph query functionality of U-P2P.

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Versioning Queries

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Versioning Queries

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Versioning Queries

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Versioning Queries

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Versioning Queries

Ex: Find all second generation edits of article “B”

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Versioning Queries

Ex: Find all sibling articles (other edits of the same parent) of article “F”

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Versioning Queries

Ex: Find all edits (descendents) of article “B”

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Wiki Links

In a centralized wiki, the latest version of an article is always authoritative.

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Wiki Links Because no authoritative version of an

article exists, wiki links are implemented as a search for all descendents.

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Trust Indicators If article revisions are not merged into a

single version, how should a user select which version of an article to view?

U-P2P provides a number of resource trust indicators alongside search results to provide users with additional information.

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Trust Indicators

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Trust Indicators: Document Popularity

Document popularity = Number of hosts serving the document

Ex: Document Popularity of “A” = 3

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Trust Indicators: Network Distance

Network Distance = Number of intermediate network hops between querying node and host

Ex: Average Network Distance of “A” = 0.5

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Trust Indicators: Peer Popularity

Peer popularity = Number of incoming peer connections to a specified host

Ex: Peer Popularity = 2(Assuming queried connection is outgoing)

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Trust Indicators: Similarity

Similarity = (Number of hosted articles in common) / (Total number of hosted articles)

Similarity = Size({A}) / Size({A, B, C}) = 1/3

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Conclusion P2Pedia expands on existing work by

supporting a collaboration model which supports the diversification of content.

Versioning is realized using document links which are queried through the distributed graph query capabilities of U-P2P.

General trust indicators are introduced to allow users to evaluate the quality of content.

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http://www.nmai.ca/research-projects/universal-peer-to-peer-home

P2Pedia Live Demo:http://inm-04.sce.carleton.ca:8080/up2p/

Questions?

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References

[1] “Wikipedia,” http://www.wikipedia.org/ Accessed May 4th, 2011.

[2] “Wiktionary,” http://www.wiktionary.org/ Accessed May 5th, 2011.

[3] “Lyric Wiki,” http://lyrics.wikia.com/ Accessed May 5th, 2011.

[4] “UniWiki,” http://sourceforge.net/projects/uniwiki/ Accessed May 5th, 2011.

[5] “Wooki,” http://wooki.sourceforge.net/ Accessed May 5th, 2011.

[6] “WikiCreole,” http://www.wikicreole.org/ Accessed May 5th, 2011.