CHEM237 Lecture Notes - Lecture 16: Regular Graph, Polysemy, Financial Institution
27 Jan 2019
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MODULE 10 SEARCH ENGINES
Graph
- Some nodes connected by edges
- Use a graph to represent many systems such as cities, airports and flights between them
(many systems)
o Directed graphs
▪ Each thing connecting to another thing has one arrow
▪ Can represent more complex things
▪
o A regular graph can be thought of as a connected graph where every line has an
arrow connected both ways
- Spiders/crawlers/robots
o They browse the web and collect information (explores the web looking for web
pages and collecting info.
- Indexing the web
o Focus
▪ Spider targeted on a certain topic
o Politeness
▪ Crawls around websites and is cooperative (follow the instructions of
website and doesn’t barrade the website)
▪ Denial of service attack
• Put spiders on different webpages and throw them and completely
overwhelms webpage so people can’t even access it
o Revisit frequency
▪ How often you revisit a webpage to check something
o Paywalls
▪ Subscription needed to get onto websites for example
o Dynamic content
▪ What if a webpage is judging the content you like
▪ Example, go on youtube and they show you videos you like
o Query strings
▪ Exta identifying info showing what content you want to see
- Behind the scenes indexing
o Example on youtube video
o Advanced indexing: semantics
▪ Synonym
• Big and large
▪ Polysemy
• Bank (financial institution)
• Bank (river bank) …
• Can determine which one you want by interpreting the words
around it
