Computer FundamentalsComputer Fundamentals

Lecture 12Lecture 12

MSCH 233MSCH 233

Electronic Electronic CommunicationsCommunications

• How can a PC be connected to How can a PC be connected to another computer?another computer?

• What data communication What data communication systems can you think of?systems can you think of?

Data Communications Data Communications ServicesServices

Data Communications Data Communications ServiceService

Service providedService provided

FaxFax To send a copy of a paper document To send a copy of a paper document from one place to another via phone from one place to another via phone lineline

Electronic e-mailElectronic e-mail To send a personal message to To send a personal message to another person on a different another person on a different workstationworkstation

TeletextTeletext To find out weather forecasts and To find out weather forecasts and sports information on the televisionsports information on the television

Local Bulletin board Local Bulletin board systemssystems

To receive shareware and public To receive shareware and public domain programs from a user groupdomain programs from a user group

Commercial online Commercial online servicesservices

To access massive databases To access massive databases containing all kinds of informationcontaining all kinds of information

Transferring information from one PC Transferring information from one PC to another via modem and phone to another via modem and phone

lines (or fiber-optic cables).lines (or fiber-optic cables).

TelecommunicationsTelecommunications

Translates signals from digital to analog and vise versa

What do we need to What do we need to telecommunicate?telecommunicate?

• PCPC• ModemModem• Phone linePhone line• Communications softwareCommunications software• Online service provider Online service provider

Internet IssuesInternet Issues

• Is it technically possible for Is it technically possible for computer criminals to infiltrate into computer criminals to infiltrate into the Internet and steal sensitive the Internet and steal sensitive information?information?

• What is a hacker?What is a hacker?• Can viruses enter your PC from the Can viruses enter your PC from the

internet?internet?

Important TermsImportant Terms

• Hacker:Hacker: a person who obtains unauthorized a person who obtains unauthorized access to computer data.access to computer data.

• CookiesCookies: small files on the web server to know : small files on the web server to know if you have visited the site before.if you have visited the site before.

• Certificates:Certificates: files that identify users on the net, files that identify users on the net, like digital identification card.like digital identification card.

• Encryption:Encryption: the process on encoding data so the process on encoding data so that unauthorized users can not read it.that unauthorized users can not read it.

• DecryptionDecryption: the process of decoding encrypted : the process of decoding encrypted data transmitted to you.data transmitted to you.

Security on the WebSecurity on the Web

• Data can technically be copied by Data can technically be copied by hackers if you are not alert.hackers if you are not alert.

• Set all our security alerts to high Set all our security alerts to high on your web browser.on your web browser.

• If you use online banking, make If you use online banking, make sure your bank uses digital sure your bank uses digital certificates.certificates.

E-mail PrivacyE-mail Privacy

• E-mail messages can be read by E-mail messages can be read by hackers.hackers.

• to protect your self, encrypt your to protect your self, encrypt your message with proper software.message with proper software.

Network SecurityNetwork Security

• Networks can be attacked by Networks can be attacked by intruders.intruders.

• companies need to build a high companies need to build a high security system to protect it self. security system to protect it self.

• Using access passwords, Using access passwords, encryption and firewalls will help a encryption and firewalls will help a lot.lot.

Virus ProtectionVirus Protection

• Viruses can enter a PC through floppy Viruses can enter a PC through floppy disks, the Internet or Bulletin board disks, the Internet or Bulletin board systems.systems.

• Do not open any e-mail message you Do not open any e-mail message you get.get.

• be alert when downloading files from be alert when downloading files from the web.the web.

• Install n up-to-date anti-virus software.Install n up-to-date anti-virus software.

Computer FundamentalsComputer Fundamentals

Lecture 13Lecture 13

MSCH 233MSCH 233

LANs and WANsLANs and WANs

• What is a computer network?What is a computer network?• What are the benefits of What are the benefits of

connecting computers and connecting computers and peripherals?peripherals?

What is a computer network?What is a computer network?

A network is a group of devices A network is a group of devices connected by communications connected by communications circuits so that users can share circuits so that users can share data, programs and hardware data, programs and hardware

resources.resources.

Main elements of a Main elements of a networknetwork

1.1. Physical structure; which links Physical structure; which links the equipment.the equipment.

2.2. Software; which allows Software; which allows communications.communications.

What is a LAN?What is a LAN?

A network contained in a relatively A network contained in a relatively small area.small area.

What is a WAN?What is a WAN?

A network for long distance or world A network for long distance or world wide communications.wide communications.

How can we link How can we link Networks?Networks?

• Telephone linesTelephone lines• Fiber-optic cablesFiber-optic cables• SatelliteSatellite

New TechnologiesNew Technologies

1.1. Mobile phones displaying internet Mobile phones displaying internet information information Third generation mobiles Third generation mobiles ( transmit picture and voice ( transmit picture and voice simultaneously) simultaneously)

2.2. Internet Enabled TV; allows you to Internet Enabled TV; allows you to search the web and check your e-mail search the web and check your e-mail while watching TV. while watching TV.

3. Virtual Reality; allows you to interact 3. Virtual Reality; allows you to interact with artificial objects and environments with artificial objects and environments through three dimensional computer through three dimensional computer simulation.simulation.

4. Bluetooth; a standard wireless 4. Bluetooth; a standard wireless technology that is designed to connect technology that is designed to connect mobile phones, computers and other mobile phones, computers and other devices replacing direct cable links. devices replacing direct cable links.

……New TechnologiesNew Technologies

A Simple Guide to Internet A Simple Guide to Internet ResearchResearch

By Greg SpenceBy Greg Spence

Finding InformationFinding Information

Tools available:Tools available:

1.1. Search engines.Search engines.

2.2. Directories.Directories.

3.3. Meta directories.Meta directories.

4.4. E-mail.E-mail.

Search enginesSearch engines

• A search engine is simply a A search engine is simply a database containing thousands of database containing thousands of links to websites.links to websites.

• There are over 2500 search There are over 2500 search engines.engines.

• They vary according to the type They vary according to the type of websites they index.of websites they index.

• AltaVista; AltaVista; www.altavista.comwww.altavista.com• Excite; Excite; www.excite.comwww.excite.com• Northern Light; Northern Light;

www.northernlight.comwww.northernlight.com• Hotbot; Hotbot; www.hotbot.comwww.hotbot.com• Go; Go; www.go.comwww.go.com• Google; Google; www.google.comwww.google.com

……Search enginesSearch engines

DirectoriesDirectories

• A directory groups the links to A directory groups the links to indexed sites into categories.indexed sites into categories.

• Yahoo; Yahoo; www.yahoo.comwww.yahoo.com

Meta DirectoriesMeta Directories

• A meta directory allows you to A meta directory allows you to research multiple search engines research multiple search engines and directories from one place.and directories from one place.

• MetaCrawler; MetaCrawler; www.metacrawler.comwww.metacrawler.com

E-mailE-mail

• Before the existence of web Before the existence of web browsers, specific programs were browsers, specific programs were used to obtain research documents used to obtain research documents through e-mail.through e-mail.

The Right Tool for the The Right Tool for the Job?!!Job?!!

• Excite and Google are the best Excite and Google are the best tools if you are searching a tools if you are searching a concept.concept.

• Meta search engines are suitable if Meta search engines are suitable if you are just learning about a you are just learning about a subject.subject.

• Specialty Directories are useful for Specialty Directories are useful for broad based subjects.broad based subjects.

• Directories will do an excellent job Directories will do an excellent job in researching current events, in researching current events, finding product information, locating finding product information, locating background information for a book, background information for a book, www.looksmart.comwww.looksmart.com . .

• Search engines are recommended Search engines are recommended for academic fields, for academic fields, www.northernlight.comwww.northernlight.com . .

……The Right Tool for the The Right Tool for the Job?!!Job?!!

• Interactive web search wizards can Interactive web search wizards can guide the researcher to the guide the researcher to the appropriate search engine or appropriate search engine or directory based on one of several directory based on one of several predefined categories, predefined categories, websearch.about.com/internet/webwebsearch.about.com/internet/websearch/library/searchwiz/bl_searchsearch/library/searchwiz/bl_searchwiz.htmwiz.htm . .

……The Right Tool for the The Right Tool for the Job?!!Job?!!

• Smartborg is a helpful tool, it Smartborg is a helpful tool, it analysis your key words or phrase analysis your key words or phrase and then suggest the search and then suggest the search engine that will return the most engine that will return the most relevant results, relevant results, www.teleport.com/www.teleport.com/~lensman/sb~lensman/sb//..

……The Right Tool for the The Right Tool for the Job?!!Job?!!

How to use the major search How to use the major search engines for research?engines for research?

• Alta Vista; Alta Vista; www.altavista.comwww.altavista.com• Excite; Excite; www.excite.comwww.excite.com• Northern Light; Northern Light;

www.northernlihgt.comwww.northernlihgt.com• Hotbot; Hotbot; www.hotbot,lycos.comwww.hotbot,lycos.com• Go; Go; www.go.comwww.go.com• Google; Google; www.google.comwww.google.com

Alta Vista; Alta Vista; www.altavista.comwww.altavista.com

• It indexes around 10 million web pages web It indexes around 10 million web pages web pages a day.pages a day.

• It finds actual words and pages from within the It finds actual words and pages from within the text of each web page.text of each web page.

• Boolean operators used; Boolean operators used; ANDAND (when you want all keywords in the search (when you want all keywords in the search

phrase to appear)phrase to appear)OROR (when you want either keywords in the (when you want either keywords in the

search phrase to appear)search phrase to appear)NOTNOT (exclude keywords in the search phrase) (exclude keywords in the search phrase)NEARNEAR (when you want each keyword in the (when you want each keyword in the

search phrase to be within ten words from the search phrase to be within ten words from the other)other)

……Alta VistaAlta Vista

• Wildcards; AltaVista recognizes Wildcards; AltaVista recognizes the (*) as a wildcard which is a the (*) as a wildcard which is a special character that will match special character that will match any letter, number or special any letter, number or special character.character.

Excite; Excite; www.excite.comwww.excite.com

• It is best designed when searching It is best designed when searching for information on a specific for information on a specific company and background material company and background material about that company.about that company.

• It also useful in concept searches.It also useful in concept searches.• It returns real-time data with the It returns real-time data with the

most current information. most current information.

……ExciteExcite

• Boolean operators used; Boolean operators used; ANDAND (when you want all keywords in the (when you want all keywords in the

search phrase to appear)search phrase to appear)OROR (when you want either keywords in (when you want either keywords in

the search phrase to appear)the search phrase to appear)NOTNOT (exclude keywords in the search (exclude keywords in the search

phrase)phrase)

Northern Light; Northern Light; www.northernlihgt.comwww.northernlihgt.com

• It is very strong at supplying newspaper It is very strong at supplying newspaper and magazine stories.and magazine stories.

• It returns its results in groups by It returns its results in groups by category.category.

• Boolean operators used; Boolean operators used; ANDAND (when you want all keywords in the (when you want all keywords in the

search phrase to appear)search phrase to appear)OROR (when you want either keywords in the (when you want either keywords in the

search phrase to appear)search phrase to appear)NOTNOT (exclude keywords in the search (exclude keywords in the search

phrase)phrase)

……Northern Light;Northern Light;

• Wildcards; it recognizes the (*) as Wildcards; it recognizes the (*) as a wildcard which is a special a wildcard which is a special character that will match any character that will match any letter, number or special character.letter, number or special character.

• It also recognizes (%) which only It also recognizes (%) which only matches a single character.matches a single character.

HotBot; HotBot; www.hotbot,lycos.comwww.hotbot,lycos.com

• It provides focused resources that allow It provides focused resources that allow you to quickly find resources in a specific you to quickly find resources in a specific subject area.subject area.

• It allows you to specify how your It allows you to specify how your searches should be interpreted by searches should be interpreted by selecting options from the search boxes;selecting options from the search boxes;all the words all the words any of the wordsany of the wordsexact phraseexact phrase the page titlethe page title

the person the person links to this URLlinks to this URL

……HotBotHotBot

• Boolean operators used; Boolean operators used; ANDAND (when you want all keywords in the search (when you want all keywords in the search

phrase to appear)phrase to appear)OROR (when you want either keywords in the (when you want either keywords in the

search phrase to appear)search phrase to appear)NOTNOT (exclude keywords in the search phrase) (exclude keywords in the search phrase) • Wildcards; it recognizes the (*) as a wildcard Wildcards; it recognizes the (*) as a wildcard

which is a special character that will match any which is a special character that will match any letter, number or special character.letter, number or special character.

• It also recognizes (?) which only matches a It also recognizes (?) which only matches a single character.single character.

Go; Go; www.go.comwww.go.com

• It grades the sites as Best Sites, It grades the sites as Best Sites, Very good sites and good sites.Very good sites and good sites.

• You can not use Boolean operators You can not use Boolean operators hear, instead you use (+) or (-) hear, instead you use (+) or (-) signs. signs.

Google; Google; www.google.comwww.google.com

• It claims to have features that It claims to have features that make the results returned from the make the results returned from the search more relevant.search more relevant.

• the closer together the words in the closer together the words in your search phrase, the higher the your search phrase, the higher the document is ranked in the search document is ranked in the search results.results.

……GoogleGoogle

• Boolean operators used; Boolean operators used; ANDAND (when you want all keywords (when you want all keywords

in the search phrase to appear)in the search phrase to appear)OROR (when you want either (when you want either

keywords in the search phrase to keywords in the search phrase to appear)appear)

NOTNOT (exclude keywords in the (exclude keywords in the search phrase)search phrase)

How to use subject specific How to use subject specific search engines and directories?search engines and directories?

• They are useful when searching general They are useful when searching general topics, looking for links to specialty topics, looking for links to specialty databases, trying to find product databases, trying to find product information or trying to find other information or trying to find other subject-based directories and websites.subject-based directories and websites.

• It is recommended to use them when It is recommended to use them when you wish to find out what type of you wish to find out what type of resources are available online that cover resources are available online that cover your topic your topic

How to find them?How to find them?

• The most popular directory; Yahoo at The most popular directory; Yahoo at www.yahoo.comwww.yahoo.com

• A scholarly collection of internet A scholarly collection of internet resources; INFOMINE at resources; INFOMINE at lib-lib-www.ucr.edu/main.htmlwww.ucr.edu/main.html

• Britannica’s internet guide; eBLAST at Britannica’s internet guide; eBLAST at www.eblast.comwww.eblast.com

• A good tool to find more subject A good tool to find more subject directories; The Internet Sleuthdirectories; The Internet Sleuth at at www.isleuth.comwww.isleuth.com

……How to find them?How to find them?

• Strong in politics, academic resources Strong in politics, academic resources and other general topics; Argus and other general topics; Argus Clearinghouse at Clearinghouse at www.clearinghouse.comwww.clearinghouse.com

• Look Smart at Look Smart at www.looksmart.comwww.looksmart.com• Magellan Internet Guide at Magellan Internet Guide at

www.mckinley.comwww.mckinley.com• Covers hundreds of subject areas and Covers hundreds of subject areas and

very high quality, About.com at very high quality, About.com at www.about.comwww.about.com

……How to find them?How to find them?

• WebCrawler at www.webcrawler.comWebCrawler at www.webcrawler.com• A gateway to academic resources on the web, A gateway to academic resources on the web,

AlphaSearch at, www.calvin.edu/library/asAlphaSearch at, www.calvin.edu/library/as• A directory of subject directories; Direct SearchA directory of subject directories; Direct Search

at at gwis2.circ.gwu.edu/~gprice/direct.htmgwis2.circ.gwu.edu/~gprice/direct.htm• Geared towards academic resources and Geared towards academic resources and

maintained by professional librarians; Librarian’s maintained by professional librarians; Librarian’s Index to the Internet at Index to the Internet at sunsite.berkeley.edu/internetindexsunsite.berkeley.edu/internetindex

• Open Directory Project at www.dmoz.orgOpen Directory Project at www.dmoz.org

Where can you find Meta Where can you find Meta tools?tools?

• All in One at www.allonesearch.comAll in One at www.allonesearch.com• Beaucoup at www.beaucoup.comBeaucoup at www.beaucoup.com• Dogpile at www.dogpile.comDogpile at www.dogpile.com• Inference Find at www.infind.comInference Find at www.infind.com• ProFusion at www.profusion.comProFusion at www.profusion.com• SavvySearch at SavvySearch at

www.savvysearch.com/searchwww.savvysearch.com/search• Ixquick at www.ixquick.com Ixquick at www.ixquick.com

Using Natural LanguageUsing Natural Language

• You can frame your search subject You can frame your search subject in a question form and the search in a question form and the search tool will recognize the most tool will recognize the most relevant subjects to the question relevant subjects to the question you framed.you framed.

• Ask Jeeves at www.ask.comAsk Jeeves at www.ask.com• Simpli at www.simpli.comSimpli at www.simpli.com

Hidden ResourcesHidden Resources

• Websites that require a username Websites that require a username and password to access are not and password to access are not available through search tools.available through search tools.

• Websites that store their data in Websites that store their data in databases are not available for databases are not available for search robots to locate.search robots to locate.

How can we reach these How can we reach these hidden resources?hidden resources?

• Direct Search at Direct Search at gwis2.circ.gwu.edu/~gprice/direct.htmgwis2.circ.gwu.edu/~gprice/direct.htm

• Lycos at Lycos at dir.lycos.com/reference/Searchable_Datdir.lycos.com/reference/Searchable_Databases/abases/

• Infomine at Infomine at infomine.ucr.edu/search.phtmlinfomine.ucr.edu/search.phtml

• IntelliSeek at www.invisiweb.comIntelliSeek at www.invisiweb.com

Using e-mail as an Internet Using e-mail as an Internet tooltool

• You need to send an e-mail containing You need to send an e-mail containing the search commands to an e-mail the search commands to an e-mail address.address.

• There are four free software programs There are four free software programs that are capable of searching for that are capable of searching for websites via e-mail; Agora, GetWeb, websites via e-mail; Agora, GetWeb, WebMail and www4mail.WebMail and www4mail.

• Table 5.1 may not be up-to-date, you Table 5.1 may not be up-to-date, you can check can check www.geocities.com/CapitolHill/1236/servwww.geocities.com/CapitolHill/1236/servers.htmlers.html

Using AgoraUsing Agora

• You need to submit the URL You need to submit the URL containing your search phrase.containing your search phrase.

• Keep in mind that the format is Keep in mind that the format is different for each search engine.different for each search engine.

• Place each command in the body Place each command in the body of an e-mail and send it to Agora.of an e-mail and send it to Agora.

• Consider the following examples;Consider the following examples;

……Using AgoraUsing Agora

• To search AltaVista for example you To search AltaVista for example you send the following in the body of your e-send the following in the body of your e-mail; mail; http://www.altavista.com/cgi-bin/query?http://www.altavista.com/cgi-bin/query?q=%22YOUR_SEARCH_PHRASEq=%22YOUR_SEARCH_PHRASE%22&kl=XX&pg=q&Translate=on&sear%22&kl=XX&pg=q&Translate=on&search.x=28&search.y=9ch.x=28&search.y=9

• See handout for searching other See handout for searching other enginesengines..

Using GetWebUsing GetWeb

• You simply send in the body of your You simply send in the body of your e-mail message;e-mail message;

SEARCH ALTAVISTA your_search_phraseSEARCH ALTAVISTA your_search_phrase

•

What is a Bot?!What is a Bot?!

• It is short for robot.It is short for robot.• You can also call it an intelligent agent You can also call it an intelligent agent

that can help with allsorts of mundane that can help with allsorts of mundane online tasks.online tasks.

• We are interested in bots that can We are interested in bots that can monitor online resources and e-mail us monitor online resources and e-mail us when any changes or additions are when any changes or additions are made.made.

Making the Best out of itMaking the Best out of it

• Specify your search phrase or Specify your search phrase or scope.scope.

• Do not set a lot of auto searches.Do not set a lot of auto searches.• Switch off the Bot when your on Switch off the Bot when your on

vacation.vacation.

Some useful BotsSome useful Bots

• The Informant at The Informant at informant.dartmouth.eduinformant.dartmouth.edu

• TracerLock at TracerLock at www.peacefire.org/tracerlock/www.peacefire.org/tracerlock/

• Mind-it at Mind-it at www.netmind.com/html/url-www.netmind.com/html/url-minder.htmlminder.html