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Email & Web Searches

Email & Web Searches. Kin 260 Jackie Kiwata. Overview. Email Message Transfer Agents User Agents Envelope & Contents Web Searches Search Engines Key Words Operators CSLA Library Research. Electronic Mail. Use of email by general public exploded in the 1990s

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Email & Web Searches

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  1. Email & Web Searches Kin 260 Jackie Kiwata

  2. Overview • Email • Message Transfer Agents • User Agents • Envelope & Contents • Web Searches • Search Engines • Key Words • Operators • CSLA Library Research

  3. Electronic Mail • Use of email by general public exploded in the 1990s • Prior to 90’s, used mostly in academia • Email systems composed of 2 subsystems • User Agents • Message Transfer Agents • Key idea behind email system: envelope and contents • Separate routing information from message

  4. Message Transfer Agents • Move messages from source to destination • Use daemons • Computer Science definition: processes that run in the background • NOT:

  5. Daemons • Purpose: • Establish connection to destination • Reliably transfer message • Close connection • Perform steps automatically without bothering user

  6. Daemon Example from <mailer-daemon@googlemail.com> to jkiwata2@csla.edu, date Nov 8, 2007 1:42 PM Subject: Delivery Status Notification (Failure) This is an automatically generated Delivery Status Notification Delivery to the following recipient failed permanently: ladyleedoc@yahoo.com Technical details of permanent failure: PERM_FAILURE: SMTP Error (state 13): 550 <ladyleedoc@yahoo.com> recipient rejected

  7. User Agents • Normally a program • Accepts a variety of commands, including: • Composing messages • Receiving messages • Replying to messages • Manipulating mailboxes • e.g. Outlook, Gmail, Hotmail

  8. Email - Envelope • Read by Message Transfer Agents • Not seen by person reading email • Encapsulates the message • Similar to paper envelopes transported by the post office • Contains all the information needed to transport the message • Destination Address • Priority • Security Level

  9. Email - Content • Content consists of two parts • Header • contains information for User Agents • Body - Contains the message read by the human recipient

  10. Anatomy of an Email message Header Body Return-Path: <example-return-9792-ccsxxx=bath.ac@gmail.com> Received: from roche.bath.ucla.edu ([138.38.32.21] ident=yalrla9a1j69szla2ydr) by serena.bath.smtp.gmail with esmtp; Sat, 07 Jun 2007 20:17:35 +0100 Date: Sat, 7 Jun 2001 12:35:58 -0700 From: Jane Martin<jmartin@gmail.com> To: Bob Richards <brichards@ucla.edu> Subject: Athletic Director Position Message-ID: <20030607123558.A2408@ring.CS.example.com> User-Agent: Mutt/1.2.5.1i Dear Mr. Richards: Please find my resume attached. Sincerely, Jane Martin

  11. Transfer Protocols • How User Agents talk to Message Transfer Agents • Daemons will speak one of the following protocols: • SMTP: Simple Mail Transfer Protocol • POP3: Post Office Protocol 3 • IMAP: Internet Message Access Protocol • e.g. Gmail uses POP3 to receive mail and SMTP to send mail

  12. Web Searches • Web is a terrific place to obtain info on any topic • But all too often, waste time on reviewing useless web site results • There has to be a better way!

  13. Making Searches Better 1. Use a sophisticated search engine i.e. Google 2. Choose key words wisely i.e. “Exercise Science programs” instead of “Exercise” 3. Refine search query with Operators i.e. +, -, “”

  14. Web Search Engines • Provide an interface to search for pages, images or other types of web files • Use algorithms • Work by: • Web crawling • Indexing • Searching

  15. Web Crawling • Accomplished using web crawlers, or spiders • Automated programs that browse pages on the WWW • Crawlers create a copy of visited pages for use in later analysis

  16. Indexing • Contents of stored pages are analyzed • Words extracted from titles, headings, and special fields called meta tags • Data about web pages are stored in an index database • When a user enters a search query, search engine checks the index database

  17. Searching & Results • Search engine returns results based on search query • Search engine will rank the results and show most relevant higher in the list • Most relevant = how closely key words match on web page • Issue: In 2006, spammers created websites containing random sequences of high-traffic keywords. Results were polluted with pages that contained little or no relevance.

  18. Choosing Key Words • Key to finding information quickly • Get better results if use multiple search terms that are specific • E.g. “Sports” vs. “Sports medicine programs in California” • Note: Google will ignore capitalization and common words like “and”, “or”, “how”

  19. Basic Operators • Quotes “” - Will search for pages with exact phrase - Good if know title of article - E.g. “Expression of the bilateral deficit” • Positive Terms + • If put + before a word, search engine must return results that include the word • Use if search is omitting common words essential to results • E.g. Star Wars Episode +1

  20. Basic Operators, con’t. 3. Negative Terms – - If put – before a word, search engine will omit results containing word - Use if search term has more than one meaning -e.g. vo2max test -cycle -e.g. rehab -winehouse

  21. Advanced Operators • OR search • Find results that include either of 2 search terms • e.g. vo2max test cycle OR treadmill • Domain search • Find results on one specific website • E.g. biomechanics site:www.usc.edu • Fill in the blanks search * • Ask Google to fill in the blank for you • Add an * at the part you want filled in - e.g. glycolysis discovered by *

  22. Helpful Specialized Search Sites • CSLA Library • http://www.calstatela.edu/library/ • Google Scholar • http://scholar.google.com • Searches research publications, books • Google Image search • http://images.google.com • Only returns results that contain images

  23. Practical Ex. – CSLA Library Search Usually, will use Article search Then can choose database by Subject (i.e. Kinesiology) Or choose database directly by name (i.e. Medline)

  24. Helpful Hints • Can access CSLA library databases from home • Must have NIS account • If use ERIC, can only access abstracts, not full text • Most efficient to least efficient searching terms: • Title • Keyword • Author • Abstract • All text

  25. Ex – Medline Search • You want to find studies on caffeine supplementation during high-intensity exercise bouts of varying duration on a cycle ergometer. • Use the MEDLINE database through the CSULA library • Must find the full text version (html or pdf).

  26. Extra Credit In preparation for next lecture, do the following: • Sign up for gmail (free) • Email me from your gmail account • Do this by 5:00 pm on Friday and I will add 1 extra point to your overall lab score • If you already have a gmail account, just do steps 2-3.

  27. References • Google Search Guide http://www.google.com/intl/en/help/basics.html • Wiki Search Engine page http://en.wikipedia.org/wiki/Web_search_engine • Email Tanenbaum, A. S. (2003). Computer Networks. Upper Saddle River, NJ: Prentice Hall

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