Intro to Information Systems I

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Oct 24, 2013 (3 years and 5 months ago)

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ISYS 101

Lecture #3

1

Intro to Information Systems I

Multimedia and Communications


ISYS 101

Glenn Booker

ISYS 101

Lecture #3

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Multimedia World


Multimedia presentations go beyond the vu
-
graph mode of presentation applications to
blend graphics, animation, video, and sound


Metaphor becomes theater instead of a
podium presentation


Many multimedia tools are designed for the
Web

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Interactivity


A major feature of multimedia presentations
can be the use of interactive elements


where the viewer chooses their path through
the presentation instead of seeing a fixed
series of events


Normal web pages achieve interactivity
through
hyperlinks

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Multimedia Hardware


Basic input and output hardware for
multimedia include a CD
-
ROM or DVD
-
ROM drive, sound card, and speakers

(all now standard on personal computers)


Optional equipment includes a microphone,
graphics tablet, digital camera, and a TV
video adapter


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Multimedia Hardware


Faster video cards and 3
-
5 speakers instead
of just one or two (e.g. adding a subwoofer
or going for surround sound or theater
-
grade
THX sound) help too

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Multimedia Uses


Multimedia is used increasingly for


Computer based training (CBT) or education
(CBE)


Livening up reference materials
(encyclopedias)


Creating stand
-
alone sales or information
kiosks, playing a loop of information


Even art is starting to use multimedia

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Big Files Need Compression


Multimedia takes a lot more disk space than
text, so compression techniques are
important


Algorithms are used to calculate how data
can be compressed


these algorithms are
called “codecs” (for
co
mpression/
dec
ompression)

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Compression Types


Compression techniques can be lossless or
lossy


Lossless techniques retain every bit of original
data (literally!)


Lossy techniques sacrifice some low level data
detail to produce higher levels of compression

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Graphics Compression Formats


GIF (like “gift” without the ‘t’) allows a
maximum of 256 colors (8
-
bit), uses
lossless compression, and is often used for
simpler Web graphics


JPEG allows up to 16.7 million colors

(24
-
bit), is lossy, and often used for photos
or other complex images on the Web

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Graphics Compression Formats


PNG is a new format like GIF, but isn’t
proprietary (you have to pay royalties to be
able to create GIF images)


Bitmap (BMP) is the Windows standard for
primitive graphics


is often without
compression, so bitmaps are huge


A bitmap describes every pixel’s color

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Graphics Software


Graphics software programs tend to fall into
three types for working with a single image


Paint programs, which use bit
-
mapped or raster
graphics


Drawing programs, which use vector graphics


Image editors, for modifying existing photos

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Paint Programs


Paint programs are designed to create
images at the pixel level


Easy to create stuff this way, but harder to
edit, and harder to keep smooth


Examples: Fractal Design Painter, Paint
Shop Pro, Corel Painter

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Drawing Programs


Drawing programs use vector graphics


each line is described by a math formula


Draw and shape lines, then fill in colors and
textures among them


Creates smoother images, which can be
scaled to any size


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Drawing Programs


Saves documents in EPS format, which
some printers understand


But EPS isn’t Web friendly


Examples: Adobe Illustrator, Macromedia
Freehand, CorelDRAW

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Image Editors


Image editors are for manipulating existing
pictures (e.g. photos)


Allow you to resize, crop, merge and add
special effects to the images


Examples: Adobe Photoshop and
PhotoDeluxe


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Moving Picture Software


Programs for working with moving pictures
include:


3
-
D rendering programs, for adding 3
-
D effects
to graphics (lighting, shadows, etc.)


Animation programs, for creating the illusion of
moving pictures through graphics


Video editors, for creating and editing digital
videos

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3
-
D Rendering Programs


Rendering programs account for specific
light sources, and determine shadows,
transparency, and other effects


Used to require a supercomputer to do this


Ray tracing is one technique they use


Examples: Renderman, AutoCAD,

3D Studio MAX

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Animation Programs


Animation is based on presenting still
images rapidly in succession


A movie uses 24 frames per second


Computer animation uses the same idea
with GIF images


Some programs recognize background
images versus those elements which move

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Animation Programs


Examples: Adobe LiveMotion, Macromedia
Flash, and Softimage XSI


Some high end ($$$) programs combine
animation with 3D rendering, such as
Discreet combustion, Maya Complete, and
Newtek Lightwave

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Video Editors


Video editors take input from a digital video
camera, and allow it to be rearranged, add
sound, etc.


Examples: Adobe Premiere

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Video Formats


Videos are usually in one of three formats


MPEG is the standard for full motion video,
such as DVD’s


QuickTime is an Apple standard for high
quality video and audio


AVI (formally Video for Windows) tend to be
fairly low quality

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Streaming Video


One way to get video across the Internet
quickly is to use streaming video


A small bit of video is sent continuously to
the viewer


Hence the viewer doesn’t need to download the
entire video before watching it


But the viewer also never has a copy of the
video either

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Audio Software


Audio software has improved to where most
professional recording studios don’t bother
with magnetic tape for recording


they use
computers instead


Sound uses can range from simple
background music to original compositions


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Audio Formats


Audio is digitized at 44.1 kHz for CD’s


Raw audio files are very large, hence
compression is important


MP3 is the most common format, can be
compressed up to 1/12
th

of original size


AU format is used on Sun workstations


WAV files are used in Windows, aren’t
compressed

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Audio Software


Musical instruments use MIDI language to
speak to computers


Audio applications include


Notation programs to write music


Recording and editing programs


Mixers and synchronizers to coordinate many
musical parts into one piece

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Putting it all together


Authoring software is used for assembling
multimedia presentations from all of its
parts (sound, graphics, video, animation)


Uses a scripting language to coordinate
activities


Example: Macromedia Director

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Virtual Environments


Massive improvements in multimedia have
led to the concept of creating virtual
environments


Hardware like head
-
mounted displays make
it possible to present a realistic fake
environment


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Virtual Formats


VRML (Virtual Reality Modeling
Language) is a front
-
runner in providing a
virtual environment via the Internet


Used for games, training, and data
visualization


One common game environment is the

Multi
-
User Dungeon (MUD)

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Telecommunications


Some aspects of computer networking
depend on the existing telecommunications
infrastructure


Most home users use analog telephone lines
for their modem connection to the Internet


Telecom is moving from analog signals on
copper wires to digital signals

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Telecommunications


Analog wires can go up to T1 speed (1.5
Mb/s) or 24 voice signals


Digital signals may be sent across fiber
optic cables, or beamed using microwaves


Fiber optics can go up to T3 speed (43
Mb/s) or 672 voice signals using pulses of
light

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Telecom Standards


Telecom standards are defined by the ITU,
a branch of the United Nations


Telecom is a vital service for safety, so it is
heavily regulated to ensure service to
unprofitable regions


Private or leased lines can be used for
communication too

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Modems


Modems
mo
dulate and
dem
odulate signals


That converts a digital signal to analog, and
back again at the other end


Modem speeds evolved from 300 bits/sec
(circa 1970’s) to the theoretical limit of
56,000 bps

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Modem Standards


The current limit is defined by the V.90
standard (56 kbps)


Earlier standards were V.34 (28.8 kbps) and
V.32 (14.4 kbps)


Modems negotiate the fastest connection
both sides can handle


Faxes can also be sent, generally at 9.6 kbps

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Need for Speed


Bandwidth, or the speed at which data can
be sent and received, is critical for emerging
applications


Video conferencing needs 10 Mbps


High definition TV (HDTV) needs 11 Mbps


Broadband refers to digital telecom at
speeds of 1.5 Mbps and up (T1 or better)

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Broadband Options


ISDN is the most common broadband
service


Basic ISDN goes up to 128 kbps


Primary ISDN goes up to 1.5 Mbps (T1)


Broadband ISDN doesn’t exist yet; claims up to
622 Mbps

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Broadband Options


Digital Subscriber Lines (DSL) is still rare


Some versions are asymmetric (you can have
much slower upload speed than download)


Range from 128 kbps to 9.1 Mbps speeds


Speed varies depending on how far you are
from the provider


SONET is a future possibility; range from
52 Mbps to 1 Gbps

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Cable Modems


Cable modems use coaxial cable from your
TV cable provider to feed Internet access


Cable bandwidth is shared among the users
in the local area


more users online means
slower speeds for each user


Speed can range from 100 kbps to over
2000 kbps

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Power Lines?


Internet connections can be passed over
power lines too


Still experimental


Not likely to work in the US

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Phone, TV, and Internet Merge


Some appliances can let a normal TV show
the Internet (WebTV)


Phone service and Internet service can share
the same lines, and some computer
applications handle phone and fax functions
over normal phone lines


The lines of distinction are blurring

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Computer Networking


Networking allows computers to
communicate with each other, and share
resources (e.g. printers)


Networks range in size from global to
consumer


Networks are much faster than just using
telecom equipment

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Types of Networks


A single building or group of buildings
might use a Local Area Network (LAN)


Several related sets of facilities might use a
Metropolitan Area Network (MAN)


Global corporations use a Wide Area
Network (WAN)


Networks can be public or private

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Switching


Networks control the flow of data using
switching


Two major types of switching


Circuit switching changes the circuit to produce
a physically direct connection; is very fast


Packet switching sends packets of data which
get reassembled at the other end to produce the
message; is much cheaper than circuit

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Protocols


Network protocols are the language spoken
across the network


TCP/IP is the language of the Internet


NetBEUI is a Windows networking protocol


AppleTalk is an Apple networking protocol


IPX is a Novell protocol

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Network Layers


Networks function by taking data and
adding various pieces of information to it in
order to help it get to its destination


The layers of the network describe what that
information is and how it is used


The OSI reference model is the most
common system for networking

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Network Hardware


Networks rely on each computer having a
network interface card (NIC) to allow them
to be connected to the network


Like a modem allows connection to the Internet


Most NIC’s are for Ethernet networks


Ethernet speeds include 10, 100, and 1000
Mbps (the last one is Gigabit Ethernet)

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Network Hardware


Most networks still use cables


Thick, thin, or 10base
-
T Ethernet cables


Token Ring cables


Coaxial cable


Fiber
-
optic cable


Infrared and radio signals are used for
wireless networks

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Network Hardware


Other network hardware might include:


Switches, to control where data may go


Router, to convert one language into another


Hubs, to connect computers which speak the
same language (protocol)


Bridges, to connect major parts of the network
together

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Network Terminology


Every device on a network (computer,
printer, etc.) is a “node”


Peer to peer networks work well for small
offices and home; allow sharing of files,
printers, and Internet connection


Client/server networks use servers to
manage the network, and control access to
different nodes

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Network Operating System


Normal operating systems routinely include
software to allow peer to peer networking


Client/Server networks require a
networking operating system (NOS)


Windows Servers (NT, 2000, etc.)


Novell NetWare


Unix

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Network Topology


Network topology is the layout of a
network, like a street map to show where
roads go


The “bus” topology connects everything
along a line (like a bus route)


good for
peer to peer networks


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Network Topology


A “star” topology puts a hub in the middle,
and everything connects to it


A “ring” topology passes information in a
circle, and every computer either passes it
along or uses it (e.g. IBM’s Token Ring)


More complex topologies are variants on
these basic structures

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WAN Structure


WAN’s are essentially a group of networks
which are connected by a “backbone”
(generally a very fast dedicated connection)


Most use circuit switching, not packet


Each local network connects to the WAN
via a POP (point of presence), similar to
how you connect to the Internet

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WAN Protocols


Special protocols are used for WANs


X.25 is for phone line connections, goes up to
64 kbps (like MAC machines)


ATM (Asynchronous Transfer Mode) goes up
to 155 Mbps

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Why WAN?


Most WANs are used for sharing files and
email across a large organization


Some also handle transactions (e.g. credit
card authorization)


Specific business
-
to
-
business transactions
can be done securely using Electronic Data
Interchange (EDI) standards