DCS/CSCI 2350: Social & Economic Networks WWW: Information - - PDF document
12/8/19 DCS/CSCI 2350: Social & Economic Networks WWW: Information Networks Chapters 13, 14 Mohammad T . Irfan 1 Questions 1. What does the web look like? [Ch 13] 2. How does Google search it? [Ch 14] 3 1 12/8/19 Information network
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u Common elements of social and economic
u Graphs, paths, giant components u Connections to matching markets and auctions
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u Application for sharing info over the Internet u Created by Tim Berners-Lee (1989) u 2 perspectives
u Web pages: Make documents easily available to
anyone on the Internet
u Browser: Retrieve and display documents
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u Web organizes information in a unique
u Different from library system u Different from folders in a computer u Different from indexing u Hypertext
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u Replaces linear structure of text by pointers u Concept dates back to 1950s
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u Citation network
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u Semantic network
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u Vannevar Bush (1945)
u Associative memory in “Memex” u Cited by Tim Berners-Lee
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u Navigational functions (1990s)
u Static web pages
u Transactional functions
u Dynamic, real-time operations
u Web 2.0
u New attitude to technology, not new technology 1.
Collective creation and maintenance of shared content (Wikipedia)
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Move personal data to corporate servers (Gmail)
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Network among individuals, not just web pages (Facebook)
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u Nodes: Web pages u Directed edges: Links u bowdoin.edu à Arts à Museum of Art à
u A directed cycle
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u Google “Bowdoin”
u What do you see? u Why is Bowdoin College ranked first? (Why not
James Bowdoin?) u Google’s source of information is the web
u No expert intervention
u There must be enough information intrinsic
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u 1960s: Search repositories of newspapers,
u Done by specialized people
u Challenges in web search
u Synonymy: scallion vs. onion u Polysemy: jaguar (you mean the animal or the car
u Search results must be dynamic u Abundance of information (opposite of needle-in-
haystack)
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u Voting by in-links u PageRank u Hubs and authorities
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u Highest in-degree node is ranked first, and so
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u Google, Bing, (Yahoo!, Ask) u PageRank is a central ingredient of Google
u There are more ingredients
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u Combination of links, text, and clicks
u Anchor text: “I’m a student of Bowdoin College.”
u Moving target
u Google’s changes in algorithm causes millions of
dollars of damage to many companies
u Companies seek help from SEOs to climb up the
ranking
u “white hat” vs. “black hat” optimization (later)
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u Intuition u Update rule u Demo
u NetLogo
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