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Web Searching


									   Day 21

Web Searching
        The Vast Internet
Billions of pages
Triples about every two years
   How the web is indexed
Search Engines
– Single-Threaded (Spider-based)
– Multi-threaded (Meta) Search Engines
Subject Indexes
  Characteristics of All Web
Limited Samples
– No central, all-inclusive index
– never completely current
All indexes miss some content
      You need powerful search
      Varying Samples

Search Engine      Estimate
Google            3,033        3,083
AlltheWeb         2,106        2,112
AltaVista         1,689        1,000
WiseNut           1,453        1,500
Hotbot            1,147        3,000
MSN Search        1,018        3,000
Teoma             1,015         500
NLResearch         733          125
Gigablast          275          150
Unique Results
Single-Thread Search Engines
Powerful Searching Features
 –   + (Match All Terms)
 –   Match Any Term
 –   - (exclusion)
 –   “Phrases”
 –   Title Search
 –   URL Search
 –   Domain Search
Multi-threaded (Meta) Search
Sample Multiple Other Databases in one
Broader sample than single-thread
– Can chose which other single-thread to
Less options for specific search control
– Can’t do URL, Title, and exclusion Searches
Ixquick (
SurfWax (
Dogpile (
ProFusion (
 Subject Directories (general
         e.g., yahoo)
Substantial Sites Organized in
Categories (by humans)
Good for searching for general topics
Yahoo is largest on the Web
– over 1 million sites listed in their subject
Looksmart is another subject directory
used by MSN
Subject Directory / Crawler-Based Search
           Engine Combination
It is becoming more popular to link subject
directories with crawler-based search engines
These look first within subject directory and if
that fails, they look within a crawler-based index:
 – E.g.1, Yahoo’s extensive subject directory is seached.
   Yahoo then calls Google’s crawler based engine
 – E.g.2, MSN used the Looksmart subject directory then
   calls on Inktomi’s crawler based engine.
Data Collection Highway
% of Web Users Using Specific Search
       Engines Each Month

          US Digital Media Universe Audience Reach
          Home & Work Users, January 2003
     Day 22

Network Technology

Understand the fundamentals of data
communications and the criteria for
choosing a communications medium
Explain how networking media, devices,
and software work together to provide data
networking services
           Fundamentals of
– Transmission of a signal by way of a medium
– Contains message comprised of data and
Communication medium
– Anything that carries a signal between a sender
  and a receiver
         Characteristics of
Analog signal

– Continuously changes over time

Digital signal

– At any given time is either high or low

Signal frequency

– Speed at which signal can change from high to
   Transmission Capacities

– Range of signal frequencies that can be sent
  over a given medium at the same time
Broadband media
– Significantly faster than narrowband
– Any media faster than 200 Kbps (kilobits per
  second) or 2 Mbps (megabits per second)
– Anything below 200 Kbs
          Networking Media

Twisted-pair cable
– Cable consisting of pairs of twisted wires
– Used to boost signal so that it can travel longer
Coaxial cable
 – Inner conductor wire surrounded by insulation, a
   conductive shield, and a cover
Fiber-optic cable
 – Thousands of thin strands of glass or plastic bound
   together in a sheathing
Networking Media (Continued)

Microwave transmission
 – High-frequency radio signal that is sent through
   the air
Communications satellite
 – A microwave station placed in outer space
Global positioning system (GPS)
 – Uses satellites to pinpoint the location of objects
   on earth
Networking Media (Continued)

Wireless fidelity (Wi-Fi)
 – Wireless networking devices that use the 802.11
 – Uses wireless access points
 – Enables digital devices to communicate wirelessly over
    short distances
 – Communicates at speeds of up to 1 Mbps within a range
    of up to 33 ft
Infrared transmission
 – Sending signals through the air via light wave
       Networking Devices
– Modulates and demodulates signals
– Cable modem
    Provides Internet access over a cable television
– DSL modem
    Connects digital devices using a digital signal
    over telephone service (POTS) lines
Network adapter
– Computer circuit board, PC Card, or USB
   Network Control Devices
– Used as a central point for connecting a series
   of computers
– Fundamental part of most networks
– Connect multiple network segments
– Connect two or more network segments
  Network Control Devices
 – A network point that acts as an entrance to
   another network
 – Can divide a single network into two logically
   separate networks
Wireless access point
 – Receives and transmits data to wireless
 – Device or software that filters the information
   coming onto a network
Radio Frequency Identification
       (RFID) Devices

Tiny microprocessor combined with an antenna

Tracks merchandise from supplier to retailer to
Note: there are a lot of good questions that
 can be reviewed on the posted lecture
 materials--Hollywood Squares
Day 23

          How to create a LAN

I.      Connect the hardware together
II.     Install software and “protocols”
III.   Install “services”
IV.     Set up files to share between
      I. Hardware to connect
Computers with NIC cards in them
– Now the NIC is often on the motherboard
Hub or Switch
– What could the downside of using a hub be?
– Which is faster a switch or a hub?
– Which is more secure a switch or a hub?
– Usually your gateway to your ISP and the Internet
Suitable operating system software for networks such as
   – Windows XP (workstation)
   – Server (Windows 2003 Server)
   – NOS (Windows 2003 Enterprise) Protocol is the common data
     communication language between computers.

Protocol determines the following:
   – the type of error checking to be used
   – data compression method, if any
   – how the sending device will indicate that it has finished sending
     a message
   – how the receiving device will indicate that it has received a
           KEY PROTOCOLS

  – NetBEUI stands for NetBIOS enhanced user interface. In
    turn, NetBIOS stands for network basic input/output system.
    This is an unroutable network protocol used by DOS,
    Microsoft Windows and OS/2-based systems to
    communicate with locally-attached file servers.
  – DOES NOT require special configuration
  – TCP/IP is the primary Internet protocol
  – TCP is one of the main protocols in TCP/IP networks.
    Whereas the IP protocol deals only with digital data packets,
    TCP enables two hosts to establish a connection and
    exchange streams of data. TCP guarantees delivery of data
    and also guarantees that packets will be delivered in the
    same order in which they were sent.
  – DOES require some configuration

For example: file and print sharing, FTP,
Web, etc.
IV. Set up what you want to
Networking Activities
               #1 Crossover Cable
                 The most simple connection

 – For transferring data from one machine to another
   when not on a LAN (perhaps an old hard drive to a
   new one)
 – Playing games without a hub (outside or in a car)
     Pin #    Signal            Straight      Crossed-Over Side
       1     Send +      White w. Orange     White w. Green
       2     Send -      Orange              Green
       3     Receive +   White w. Green      White w. Orange
       4       idle      Blue                Blue
       5       idle      White w. Blue       White w. Blue
       6     Receive -   Green               Orange
       7       idle      White w. Brown      White w. Brown
       8       idle      Brown               Brown
                                                         More on cables
Note: “White w. Orange” means White with Orange Stripe
      #1 Crossover Cable Instructions
I. Hardware
  – Plug crossover cable into NICs of both machines
II. Software and Protocols (assuming XP)
  – On each machine configure TCP/IP
       StartControl PanelNetwork Connections
         – Or right click on “My Network Places” and select properties
       Right clink on “Local Area Connection” and select properties
       Make sure your NIC card is showing
       Select “Internet Protocol (TCP/IP)” or install if necessary
       Click on Properties [Note: discuss briefly getting IP address automatically
       from a DHCP server]
       Select “Use the following IP address” and type in the following
         – IP Address: for one machine and for the other
         – Subnet Mask: for both machines
         – Click “OK” (gateway is not needed as we have no Internet connection)
      #1 Crossover Cable Instructions
III. Services
  – File and Printer Sharing for Microsoft
    Networks is installed by default on XP.
  – Get in the same workgroup
        Right-click on My Computer and select
        properties. Select the Computer Name tab.
        Left-click on the properties button.
        Make sure the workgroup names are identical.
        Use Change button toward the bottom of the
        current window if necessary.
   #1 Crossover Cable Instructions
IV. Files to share
   –   Right-click on a folder you wish to share. Then
       left-click on the Sharing and Security selection.
   –    Check the “Share this file on the network”
   –   Click the Apply button and then the OK button
       when you have finished the information. A hand
       should appear under the file or folder indicating
       that it has share-level access.
   Go to “My Network Places” and enjoy your
              workgroup resources!
        #2 Hub or Switch
Exactly the same as #1, except regular
straight-through cables are plugged
between the NIC cards and the hub or
  Networks for Your Home

Wired option – install a router and CAT5
Twisted-pair cable through your house
“No-New-Wires” for a home network
– Wireless (Wi-Fi) – Wireless router and PC
    Set secure login and encrypt transmissions!
– HomePlug – House AC electrical wires
– HomePNA – House phone wires
      Networks for Your Home

               Wi-Fi       HomePlug    HomePNA
Speed (mbps)   11          14          10

PC Card        $70-$110    n/a         $50-$60
USB Adapter    $70-$145    $150-$180   $55-$60
Router/ Access $135-$150   $80-$130    $150-$180
     #3 Add a HomePlug
– Plug HomePlug adapter into electrical outlets.
    no power box or strip can be in between

– Plug straight through cables into adapter box.

– Watch for blinking lights indicating there is a
         Wireless Networks
Range 100 – 500 ft.
– Can be limited by
  walls, metal, people
Throughput 1 – 11
– User mobility
– Installation speed &
– Scalability
          Your Gateway

The gateway connecting your home LAN
to the Internet is normally done through a
– dial-up modem
– DSL router/modem
– Cable router/modem
      #4 Remote Desktop
Remote desktop allows you to work on a
computer and view the screen as though
you are sitting right there even though you
may be half a world away (like China)!
          #4 Remote Desktop
Set your computer to allow remote access.
  – Right click on “My Computer” and select properties
  – Click on the “Remote” tab and check “Allow others to
    connect remotely to this computer”
  – Note: you must have an administrator account unless
    you specifically “Select Remote Users”
  – Click “OK”
  – Note: You must have a static IP address or know what
    the current IP address is for this machine
Connect remotely to the machine
  – Start All Programs Accessories
    Communications Remote Desktop Connection
         #4 Remote Desktop

You may also
  – Print remotely or to your local printer
  – Copy and past files between your remote desktop
    and your local machine
Directions: when connecting click “Options>>”
  – On the “Local “Resources” tab check “disk drives”
    and “printers”
  – Then “Connect”
    #5 Testing Connectivity
            Demo with Internet connection

Tracert (trace route)

IPCONFIG (to get your IP address)
            #7 Visual Traces
Visually trace
  – How many hops to favorite URLs
  – Where fraudulant junkmail is coming from and
    report it
  – Who owns a particular IP address

Some free trial products include
  – VisualRoute
  – Visual WhoIs
  – Aet_Tracer
          #8 Voice over IP
Talk to family and friends across the
country or across the world free.
– They must also have a computer running the
  same VoIP program

Possible free software includes Skype
– Download it at
   Day 24

Web Commerce
Define e-commerce and understand its role as a
transaction processing system
Define the three types of e-commerce and
mobile commerce, listing the benefits and
challenges associated with each
Discuss several examples of how e-commerce
and mobile commerce are being used to provide
List the components of an e-commerce system
and explain how they function together to
provide e-commerce services
     Types of E-commerce
Business-to-consumer e-commerce (B2C)

– Connects individual consumers with sellers

Business-to-business e-commerce (B2B)
– Supports business transactions across private
  networks, the Internet, and the Web
Consumer-to-consumer e-commerce (C2C)
– Connects individual sellers with people
  shopping for used items
  M-commerce Technology
Mobile commerce (m-commerce)
– E-commerce that takes place over wireless
  mobile devices
Technologies and standards
– Wireless Application Protocol (WAP)
– Wireless Markup Language (WML)
– Bluetooth
Benefits and Challenges of E-
Buyers enjoy the convenience of shopping from
their desktop
B2C e-commerce
 – Levels the playing field between large and small
 – Established businesses must alter systems and
   business practices
 – Social concerns
  E-Commerce Applications
E-tailing provides customers with

– Product information

– The ability to comparison shop

E-tailing options

– Set up an electronic storefront

– Lease space in a cybermall
Online Clearing Houses, Web
Auctions, and Marketplaces

Provide a platform for businesses and
individuals to sell their products and belongings

Online clearinghouses

– Manufacturers can liquidate stock

– Consumers can find a good deal
Online Clearing Houses, Web
Auctions, and Marketplaces

Most popular auction/marketplace


Auction houses

– Do not accept liability for problems that buyers
  or sellers may experience
E-Commerce Implementation
Implementing e-commerce

– Requires expertise

– May require large investment

E-commerce host

– Business that takes responsibility for setting
  up and maintaining an e-commerce system
– Requires significant infrastructure changes
Changes may be required in
– Personnel, manufacturing processes, storage,
  shipping, information systems, etc.
Organizations expanding to the Web
– All areas of business are affected
    Manufacturing, finance, sales, customer service
Web Server Software
– Responds to requests for Web pages
Web Server Utility Programs
– Provide statistical information about server
  usage and Web site traffic patterns (i.e.
E-commerce Software
– Supports e-commerce activities
– Includes catalog management, electronic
  shopping cart, and payment software
          Building Traffic
The 3Cs Approach
– Content, community, and commerce
Keywords and Search Engines
– Choose name and product names that best
  describe business purpose and features
– Select descriptive domain names
– Business-related keywords can be listed in the
  HTML meta tag
Building Traffic (Continued)
– Online e-tailers often form partnerships and
  advertise each other’s Web sites
– Online advertising methods include banner ads,
  pop-up ads, and e-mail
– Offline advertising methods include magazines,
  newspapers, radio, and television
Electronic Payment Systems
Electronic cash (e-cash or digital cash)
– Provides a private and secure method of transferring
– PayPal
      Best-known e-cash provider

E-cash benefits
– Privacy - hides account information from vendors
– Convenient if seller cannot process a credit card
Electronic Payment Systems

Electronic wallet, or e-wallet

– Encrypts and stores credit-card information, e-
  cash information, etc., securely on your


– Credit cards with embedded microchips
E-commerce Security Issues
Digital certificate
– A type of electronic business card
– Attached to Internet transaction data
– Verifies the sender of the data
– Provided by certification authorities
– Encryption
     Uses high-level mathematical functions and
     computer algorithms to encode data
E-commerce Security Issues

Digital certificates combined with Secure
Sockets Layer (SSL) technology

– Allow for encrypted communications to occur


– Used to impersonate others on the Internet
E-commerce Security Issues
Denial of Service Attacks

– Use many computers to request Web pages
  from the same Web server, at the same time

– Zombie computers

     Computers that are either hacked into or under
     the influence of a virus or worm
Business Resumption Planning
 Takes into account

 – Every conceivable disaster that could negatively
   impact the system


 – To protect data and keep key systems
   operational until order is resumed
What’s New in E-Commerce?
Phishing Threatens the
Future of E-commerce

– Phishing scams involve
  hackers that use e-mail
  and Web sites to
  impersonate an
  authentic business in an
  effort to get
  unsuspecting customers
  to type in personal and
  private information.
 – Systems that support electronically executed
Transaction processing system (TPS)
 – Supports and records transactions
Three main types of e-commerce
 – Business-to-consumer (B2C)
 – Business-to-business (B2B)
 – Consumer-to-consumer (C2C)
Mobile commerce, or m-commerce
 – Takes place over wireless mobile devices
      Summary (Continued)
Retail Web sites
– Allow consumers to comparison shop
– Makes market research easier and less intrusive
– Requires investment in networking, hardware, and a
  wide variety of software
– Requires changes in infrastructure
Hardware and networking services for e-commerce
– Must be robust and trustworthy
  Day 25

  Why Do Flowcharting?
Economically expresses process logic
   “A picture is worth a thousand words.”
Independent of implementation
– Physical or logical processes
– Supports any programming environment
Works well for technical and non-technical
Where does Flowcharting Fit
 in Systems Development?

During Analysis to document current
process logic.
During Design to communicate
specified process logic to the
implementation/construction staff.
During Implementation to document
procedures and processes.
Consider Some Examples
       Problem 1
Dave Smarsh wants to find out how much money he will
have in his savings account after a certain number of
years (the balance).
He knows:
– The amount he will deposit
– the interest rate he will receive
– the number of years he will be save his money

Assumption: interest is compounding

Develop a flowchart to calculate and print the balance in
a savings account.
Think Like A Computer:
 Outline the Process

  – Input the Data
  – Perform the Algorithm
     (Logic and Calculations)
  – Output the Results
Understand the “Algorithm”
 (Logic and Calculations)

After one year the balance is:
 – Balance = Deposit * (1 + Rate/100)
After the second year:
 – New Balance = Old Balance * (1+Rate/100)
 – New Balance = Deposit * (1+Rate/100)^2
After year n:
 – Balance = Deposit * (1 + Rate/100) ^ n
Order (Precedence) of Math
Programs use algebra rules
Avoids unnecessary characters in
Complex formulas can be on one line

     Z=                Z = (20*12)^3/15
     Order Operations

Do Everything within parentheses first.
“Inner” parentheses takes precedence over
outer parentheses
The power operator (^) takes precedence over
multiply (*) & divide (/).
Multiply (*) & divide (/) take precedence over
addition (+) and subtraction (-).
Consider the formula:
– Balance = Deposit * (1 + Rate/100) ^ n
Flowchart Symbols






Logic Flow
       Problem 1
Dave Smarsh wants find out how much money
he will have in his savings account after a certain
number of years (the balance). He knows how
much he is going to deposit, the interest rate that
he will receive, and the number of years that he
will be saving his money. (Assume that the
interest is compounding).

Develop a flowchart to calculate and print the
balance in a savings account.
#1 Solution            START

                   Deposit, Rate,

                     BALANCE =
         Deposit * (1 + Rate/100) ^ No.Years

                      Rate,                This Program
                    No.Years,              Control Structure
                                           is called:

                      FINISH               “SEQUENTIAL”
 Problem 2

Captain Beefnut, the proud owner of Beefnut
Doughnut Shop, needs a program that will
calculate and print bills for his customers.

His usual price for doughnuts is 60 cents each,
but in order to increase sales he has reduced
the price to 40 cents each if a customer buys 12
or more.

Develop this in a flowchart form.
#2 Solution

                                            Variable List
                                                                      This Program
                             Start          NOD = # of Doughnuts
                                            Bill = Amount to charge
                                                                      Control Structure
                                                                      is called:
                            INPUT                                     or Decision”

                     Yes               No
  Bill = .60 * NOD         NOD <12           Bill = .40 * NOD

                           NOD, Bill

  Consider an Extension
Suppose Captain Beefnut wanted his
program to repeat the algorithm if there
was another customer bill to calculate.
Add a loop which will accomplish this
 #2 with loop                                  Start
                                                               Variable List
                                                               NOD = # of Doughnuts
                                              PRINT            Bill = Amount to charge
                                             Heading           MoreC = More customers


 This Program                         Yes                No
                 Bill = .60 * NOD            NOD <12          Bill = .40 * NOD

 is called:
                                          NOD, Bill,
                                      “More Customers?”

“LOOPING” or                                  INPUT
“REPETITION”                    Yes
                                            MoreC = Y?

  Day 26


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