Information Consumers

1
Information Consumers

• Computer Science 01i
• Introduction to the Internet
• Neal Sample
• 20 February 2001

2
We will talk about...

• HTML odds and ends
• Internet Service Providers
• Networks Connections
• Searching
• Portals

3
Some HTML Tidbits

• Changing fonts
• ltfont faceHelvetica, Courier, Arial size2gt
• Changing colors
• ltfont colorREDgt
• ltfont colorFFFFFFgt
• Changing background images
• ltbody backgroundbackground.jpggt

4
Tables

• Basic Tables
• lttable border3gt table
• lttrgt row
• lttd bgcolorredgtHi!lt/tdgt data (aka
  cell)
• lttdgtBye!lt/tdgt
• lt/trgt
• lt/tablegt
• Wide Cells
• lttd colspan2gtThis is a double-wide celllt/tdgt
• Tall Cells
• lttd rowspan2gtThis is a double-tall celllt/tdgt

5
View HTML Source!

• In Microsoft Internet Explorer
• right-click on a web page
• select view source
• or
• select View from the toolbar
• then source
• In Netscape, same process

6
Internet Service Providers (ISPs)

• Connect isolated machines to the Internet
• On campus, Stanford is your ISP
• one of the best youll ever have )
• Thousands of them out there
• Big ones with portals and content, like AOL
• Hackers providing dial-up shell accounts out of
  the spare bedroom (www.lariat.org)

7
Picking an ISP

• What is your user profile?
• What is its pricing structure, flat or usage?
• What speed modems does it support?
• Is it Mac or Unix friendly?
• What support options are there?
• Does it offer web-hosting? Shell accounts?
• What do your friends say?

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Consumer Grade Connections

• Modem
• 56 Kilobits per second/high latency
• Free - 20 per month
• Cable modem
• 128 Kilobits per second (and up)
• 30 per month, plus hardware and setup
• Cellular Modem
• 128 Kilobits per second/high latency
• 20 per month, plus hardware
• But mobile!

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High-End/Small Office Connections

• Integrated Services Digital Network (ISDN)
• 128 Kilobits per second/low latency
• 40 per month plus hardware
• Requires new phone line in your home
• Share voice and data over the same line
• Digital Subscriber Line (DSL)
• Up to 7 megabits per second downstream, 680
  Kilobits per second upstream/low latency
• 40-250 per month plus hardware
• Normal phone lines

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Industrial Strength Connections

• T1 line
• 1536 Kilobits per second/extremely low latency
• lt 750 per month, plus installation, router and
  hardware
• T3 line
• 44.7 megabits per second/extremely low latency
• Negotiated pricing, lt 10,000 per month
• Stanford has one ( an I2 connection)

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The challenge for a Web Consumer

• Navigation
• How do I find my way around the web?

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Web Navigation

• How can structure be imposed over all the
  information out on the web?
• Bookmarks
• Pages of links
• Searching
• Portals
• Rings

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Bookmarks

• Avantages
• Convenient
• Structure added by the consumer
• Take you directly where you want to go
• Always customized properly
• Disadvantages
• Can only bookmark where youve been
• Not dynamic
• Easily get disorganized themselves
• Not accessible from any machine?
  (www.mybookmarks.com)

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Links Pages

• Advantages
• More easily organized than bookmarks
• Someone else usually does them
• Available anywhere (if you can remember)
• Disadvantages
• Rely on gatekeepers for content, updates
• can be done on your own, hard to maintain
• Still have to find them (www.yahoo.com)

15
Search Engines

• Allow searches over the text on the web
• AltaVista, goto.com, Lycos, Hotbot, NetFind,
  WebCrawler, WebDirectory, Infoseek, etc
• Another search engine appears almost every day
• Heavily automated

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How to Search the Web

• Go to your search engine
• Type in your query
• Different search engines have different search
  syntaxes and different strengths
• It is very worth it to get to know the lower
  level syntax of a search engine or two
• The search engine checks its index of the web for
  hits and returns the results

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How a search engine works

• Really a collection of several programs on
  several computers
• Information gathering programs
• Database programs
• Information serving programs

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Information Gatherer

• Automatically browses the web via web crawling
• Indexes each page as it is found
• Stores the index in a database
• What if there isnt a link to a page?

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Database Program

• Manages many gigabytes of data
• Needs to age data properly
• Must be able to return very small bits of data
  very quickly
• Runs on big machines optimized for input and
  output

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Information Serving Program

• Often called the front end of the database
• Searches the content with sophisticated matching
  algorithms
• Order the results with sophisticated ordering
  algorithms
• Formats the results into an HTML page
• Hands off the page to a web-server which returns
  the query

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Search Engine Advantages

• Examines large parts of the web very quickly
• Gives a good first cut at what is out there
• Really the only way to find most of what is out
  there
• Site search engines can actually be pretty good
  (custom software)

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Search Engine Disadvantages

• Sophisticated algorithms usually arent
  sophisticated enough
• Intelligent natural-language understanding is not
  well understood in the CS world
• 1) makes queries harder, 2) no semantic web
• False positives and false negatives. Many dont
  have useful feedback features
• Effective, narrow searches are usually more
  inconvenient than a shotgun search and human
  skimming

23
Meta Search Engines

• A search engine that queries other search
  engines
• Return results from several search engines
• Have a great future?
• Apples Sherlock, others coming

24
Deja News

• www.dejanews.com
• A searchable archive of newsgroups
• Very valuable resource
• You can get your questions answered by the
  newsgroups without ever even posting
• Content of the newsgroups is often quite
  different than the web.
• More conversational, more informal.

25
Web Portals

• Starting places on the web
• Excite, Yahoo, AOL, Netscapes Home Page
• A new one pops up almost every day
• Organize the web into various categories and
  thereby impose structure on the web
• site reviews and categorization
• search engine usually built in

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More about Web Portals

• Some customization possible -- nice
• Often provide teasers that are interesting
• Really a play to get eyeballs for advertisers
• Human intensive, hard to automate site
• As smart as computers seem, there is still no
  substitute for humans making decisions

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Web Portals

• Advantages
• provide good organization
• good news sources
• eliminate crummy websites from consideration
• Disadvantages
• gatekeepers and judgment calls
• organization still isnt quite there
• commercial motives affect content

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Sources and Further Reading

• Picking an ISP
• http//www.paintstore.com/coffeepot/column/2.html
• Network Connections
• http//www.brandx.net/help/selecting-data-services
  .html
• http//www.ifl.net/support/help.html
• Search Engines
• http//www.searchengineguide.org/cosa.htm

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Project Formica Poodles

• Were playing a search-engine game to find
  something out about the words on the web.
• Use www.altavista.com word1 word2
• Scoring?
• 2 x Count1 x Count2
• ---------------------------
• (Count1 Count2) NumHits
• Fabulous Prizes!
• www-db.stanford.edu/nsample/cs01/score.html