Presentation on theme: "Exploring the Internet 91.113-021 Instructor: Michael Krolak."— Presentation transcript:
Exploring the Internet Instructor: Michael Krolak
Tonight Roll Call Class Announcements Searching the Internet Making your web page searchable. Assignments “Intelligence is not the ability to store information, but to know where to find it.“ - Albert Einstein
Follow up from the last class How you can protect yourself from Identity Theft Never enter personal information (Acquired Characteristics) into a web site that uses only http (as opposed to https) Never send acquired characteristics (except your name) through the . Unless you encrypt your , expect that anyone can read it. Always pay close attention to the spelling of the URL (web address) when paying for anything on line. Do not respond to unsolicited s.
Follow Up (cont.) Shread all snail mail that contains personal information (especially credit card offers!!) Expect that once you throw something away, you are giving it to the public.
Feedback on Blogs Keep up with your blogs! Minimum 2 blogs per week. Keep the entries of the blog relevant to the class.
How do we find information? Memory Media –Books –Movies –Music –Art Observe Ask other people
The Problem with the Internet The “Surface Web” contains 2.5 Billion pages. Each day 7.5 million web pages are added to the World Wide Web Information is submitted to the web without any context or test of validity
Examples of Popular Search Engines (Google)www.google.com (Alta Vista)www.av.com (Lycos)www.lycos.com Search.msn.com (Microsoft) (Excite)www.Excite.com (Northern Light)www.northernlight.com
What is a Subject Directory? subject directory n. 1. An Internet research tool on the World Wide Web that organizes Internet resources by subject headings and subheadings. Subject directories are usually compiled by human beings who apply some selection criteria to resources included in the database.
Examples of Subject Directories Yahoo!www.yahoo.com BUBLhttp://bubl.ac.uk/ Internet Public Libraryhttp://www.ipl.org/ About.comwww.about.com Jump Citywww.jumpcity.com Joe Anthttp://www.joeant.com/
What is a Meta Search Engine? search engine n. 1. Meta search engines are search engines that use their own database as well as sending the query to many other search engines simultaneously (called spawning) and report the unique responses from other search engines. 2. Meta search engines that are limited to only the web, newsgroups, newspapers, and scientific journals.
Examples of Meta Search Engines Ask Jeeves -- frequently get the answer in the first pass. Jeeves allows queries in natural language.Ask Jeeves Dogpile -- for its variety of sources (web, newsgroups, newspapers)Dogpile Ixquick Metacrawler ProFusion
What is the Deep Web? Estimated to be 500 times (1.25 trillion web sites) the size of the surface web.
What is a spider? n. 1. An automated program which crawls over the World Wide Web, gathering web pages for search engines. Spiders will ignore sites that explicitly state not be indexed by the search engines. Also referred to as a webcrawler, crawler, or bot
What are Meta Tags meta tags n. 1. Attributes that describe information about the content of the document. Some spiders use these tags to determine the relevance of a site to future queries. Example
How do search engines work?
What is Boolean Logic? We use Boolean Logic to evaluate the truth of one or more propositions. There are three important operators: AND, OR, NOT AND – only true if A and B are both true. OR - only true if either A or B is true. NOT - only true when A is false. When searching for information, we use Boolean logic to find results that are relevant to our search terms. If a web page is relevant to a search term, the search engine evaluates the page as true.
Examples of Searching with Boolean Logic Yankees and Choke –All web pages that contain the terms Yankees and Choke. Yankees or Choke –All web pages that contain the word Yankees. –All web pages that contain the word Choke –All web pages that contain the terms Yankees and Choke Choke and not Yankees –All web pages that contain the word Choke, but don’t contain the word Yankees
More Advanced Uses of Boolean Logic If you are looking for a proper name, a phrase, or an other collection of words that normally are found together, then enclose them in double quotes, i.e. "President Gerald Ford". If the web page should have one or more words that must be on the page, then use the logical And, i.e. President And Ford And "United States". If the web page may have different forms of the name, or titles, etc. then use the logical Or, i.e. President Or "Vice President" Or Representative And "Gerald Ford". If document should exclude a word or phrase, then use the logical Not, i.e. "Gerald Ford" Not "Ford automotive" and Not "Ford car" and Not "Ford truck".
Other Helpful Hints While not Boolean logic, some search engines allow concepts like -- NEAR and FOLLOWED BY are also allowed, to indicate the relationship of the words or phrases other words and phrases. Normally these relations can be which comes first or whether the word is within a certain number of words to the first word. This concept is called proximity logic. Not all search engines use the AND, OR, NOT notation some like Alta Vista use " +" for AND and "-" for NOT.
The Way Back Machine Frustrated by dead links – there is an answer. The WayBack Machine at Just fill in the URL of the dead link and the links history will give the history of the link and allow you to view the dead link.
Tips for Using Search Engines When searching for a large scale database, it is important to be extremely precise. Avoid using vague or common words that will only produce millions of pages. Read the instructions for each new search engine you use. There are many different methods of searching between the search engines and subject directories.
Finding Audio and Video Images.google.com – Good source of images – One of the few search engines that provides searches for video.www.dogpile.com – Provides limited video and image searching capabilitieswww.fazzle.com