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INTERNET STUDIES
LUMSA
2016/2017
Francesca
Comunello
[email protected]
@fcomun
2. DATA COMPRESSION
LOSSY VS LOSSLESS COMPRESSION
 “Lossless compression is a class of data compression
algorithms that allows the original data to be perfectly
reconstructed from the compressed data.
 By contrast, lossy compression permits reconstruction only of
an approximation of the original data, though this usually
improves compression rates (and therefore reduces file
sizes)” (Wikipedia)
 Lossless data compression is used in many applications. For
example, it is used in the ZIP file format. It is also used as a
component whitin lossy data compression technologies. It is
used in machine-to-machine communication
LOSSY COMPRESSION
 Aim: reduce source size and transmission
time
 It is most commonly used to compress
multimedia data (audio, video, and images),
especially in applications such as streaming
media and Internet telephony.
 Files or data streams contain some irrelevant
information (for a particular purpose or for a
specific human being:
 a picture may have more detail than the eye can
distinguish;
 an audio file does not need a lot of fine detail
during a very loud passage.
LOSSY COMPRESSION
 Video can be compressed immensely (e.g. 100:1) with
little visible quality loss.
 Audio can often be compressed at 10:1 with
imperceptible loss of quality.
 Still images are often compressed at 10:1, as with
audio, but the quality loss is more noticeable,
especially on closer inspection.
 e.g. Jpeg (images), MPEG 4 (video), MP3 (audio), etc.
(since 1995). A file created using the
setting of 128 kbit/s will result in a file
that is about 1/11 the size of the CD file
created from the original audio source.
NAPSTER
Initial release: 1999
Peer-to-peer file
sharing service
“Napster specialized
in MP3 files of music
and a user-friendly
interface”
Legal challenges
and shutdown
(2001)
VIDEO COMPRESSION
 A typical MPEG-4 lossy compression video has a
compression factor between 20 and 200.
 Some video compression schemes typically operate on
square-shaped groups of neighboring pixels
(macroblocks). These blocks of pixels are compared from
one frame to the next, and the video compression codec
sends only the differences within those blocks.
3. COMMUNICATION PROTOCOL
 ‘In telecommunications, a communications protocol is
a system of rules that allow two or more entities of a
communications system to communicate between
them to transmit information via any kind of variation
of a physical quantity’ (source: wikipedia).
 Systems typically use a set of cooperating protocols,
sometimes called a protocol family or protocol suite
(e.g. TCP/IP protocol suite).
WHY IS THE TCP/IP SUITE RELEVANT?
 First, it became a “de facto” standard allowing for worldwide
network interoperability
 It is an ef ficient protocol (it does not always happen that the
“best” standard wins market competition, e.g.: VHS vs
Betamax)
 It is not a “proprietary” standard
 It is at the core of the rapid spred of the internet
TRANSMISSION CONTROL PROTOCOL
(TCP) AND THE INTERNET PROTOCOL (IP)
 TCP/IP provides end-to-end connectivity specifying
how data should be packetized, addressed,
transmitted, routed and received at the destination.
TCP
IP
THE INTERNET PROTOCOL (IP)
 The internet layer has the responsibility of sending
packets across potentially multiple networks.
Internet working requires sending data from the
source network to the destination network. This
process is called routing.
The Internet Protocol (IP) performs two basic
functions:
 Host addressing and identification: it is
accomplished with a hierarchical IP addressing
system.
 Packet routing: the basic task of sending packets of
data from source to destination by forwarding them
to the next network router closer to the final
destination.
THE INTERNET PROTOCOL (IP)
 Routers forward data packets
 The routers keep making these best effort routing
decisions until the packet reaches its destination.
THE TRANSMISSION CONTROL PROTOCOL
(TCP)
The TCP is a connection-oriented protocol
that addresses numerous reliability issues
in providing a reliable byte stream:
-
data arrives in-order
data has minimal error (i.e. correctness)
duplicate data is discarded
lost or discarded packets are resent
includes traffic congestion control.
COMPUTING EVOLUTION
Evolution
Human - computer interaction
MAINFRAME COMPUTING
(1940-1980)
One computer, many users
PERSONAL COMPUTING
(1980-2000)
One user, one computer
PERVASIVE COMPUTING
(2000 - now )
One user, many computers
1. MAINFRAME COMPUTING
 Used in large institutions
 Proprietary operating system
 Execute many programs
concurrently
Image: ENIAC computer (1946 – 1955)
Additional reference: The imitation game
(2014) (Alan Turing)
MOORE LAW (1970)
 Processor speed, or overall processing power for
computers, will double every two years.
2. PERSONAL COMPUTING
 1973: the Xerox Alto,
developed at Xerox PARC
in 1973 (it uses a mouse,
the desktop metaphor,
and a graphical user
interface (GUI).
 1984: the Macintosh
(Apple) was the first
successful mass-market
mouse-driven computer
with a graphical user
interface or 'WIMP'
(Windows, Icons, Menus,
and Pointers).
COMMAND LINE INTERFACE
USER-FRIENDLY INTERFACE (WIMP)
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GUI: GRAPHIC USER INTERFACE
 WIMP (Windows, Icons, Menu, Pointing device)
 QWERT Y keyboard, mouse
 Direct manipulation of the dataspace
 The pointer represents the user on the screen: a
virtual Doppelgänger (alter ego)
 The user get visual feedbacks.
USER FRIENDLY INTERFACE
 Users cognitive resources can be used
to accomplish other tasks
DEFINING INTERFACE (JOHNSON)
 “Software that shapes the interaction between user
and computer”.
 Computer as a symbolic system
 Space to be explored
Humans – Machines interaction
(Norman)
 “We are analog beings trapped in a digital world , and the
worst part is, we did it to ourselves. ”
 Machines do better with digital encoding . The problem comes
about in the form of interaction between people and machines .
 People do best with signals and information that fit the way
they perceive and think, which means analogous to the real
world.
 Machines do best with signals and information that is suited
for the way they function, which means digital, rigid, precise.
So when the two have to meet, which side should dominate?
Reference: Norman, D. A . “The invisible computer ”, MIT Press, 1997.
MACHINE PERSPECTIVE
PEOPLE
MACHINE
Unclear
Accurate
Disorganized
Organized
Inattentive
Attentive
Emotional
Unemotional
Illogical
Logical
HUMAN PERSPECTIVE
PEOPLE
MACHINE
Creative
Accurate
Tolerant
Severe
Attentive to change
Insensitive to changes
Talented
Without imagination
MULTITOUCH AND “NUI” (NATURAL
UI)
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SPEECH RECOGNITION
 Siri: voice command
https://www.youtube.com/watch?v=8ciagGASro0
TOUCH USER INTERFACE
MOTION DETECTION
 Nintendo Wii
HUMAN COMPUTER INTERACTION (HCI)
Human–computer interaction (HCI) researches
the design and use of computer technology,
focusing particularly on the interfaces between
people (users) and computers.
 Researchers in the field of HCI both observe
the ways in which humans interact with
computers and design technologies that lets
humans interact with computers in novel ways.
(Source: Wikipedia)
HUMAN COMPUTER INTERACTION (HCI)
 2 main terms: functionality and usability
 Functionality of a system is defined by the set of
actions or services that it provides to its users .
 Usability of a system with a certain functionality
is the range and degree by which the system can
be used efficiently and adequately to accomplish
certain goals for certain users.
Source: Karray et al. 2008
3. PERVASIVE/UBIQUITOUS COMPUTING
 Term created by Mark
Weiser (1988) at Xerox
Park.
 Embedding
microprocessors in
everyday objects so they
can communicate and
share information.
 Mobile trend: pervasive
computing devices are
completely connected and
constantly available.
 Some devices: PDA , smart
phones, notebook, tablet,
etc.
THE INTERNET
THE INTERNET: A DEFINITION
“Internet refers to the global information system that (i) is logically linked together by a globally unique
address space based on the Internet Protocol (IP) or its
subsequent extensions/follow -ons;
(ii) is able to support communications using the
Transmission Control Protocol/Internet Protocol
(TCP/IP) suite or its subsequent extensions/follow -ons,
and/or other IP-compatible protocols;
(iii) provides, uses or makes accessible, either publicly
or privately, high level services layered on the
communications and related infrastructure described
herein.
Federal Networking Council (FNC) - 1995
THE INTERNET CULTURE (CASTELLS, 2001)
It is characterized by a four-layer structure:
 the techno-meritocratic culture;
 the hacker culture;
 the virtual (online) communitarian
culture;
 the entrepreneurial culture.
THE PC CULTURE
 The Pirates of
Silicon Valley
Documentary
APPLE AND MICROSOFT
a
THE WEB
 The World Wide Web functions
as a layer on top of the Internet.
 The Web is an information space
that can be accessed through
the Internet. Web Pages are
connected by links and can be
explored using a browser
(Firefox, Chrome, Safari, etc.) .
TIM BERNERS LEE AND THE WEB
 1991: Tim Berners-Lee invents
the World Wide Web.
 1993: Marc Andreessen
creates predecessor to
Netscape browser (Mosaic).
 "I just had to take the
hypertext idea and connect it
to the TCP Protocol and
Domain Name System ideas
and – Ta-da! – the World Wide
Web!” (Tim Berners-Lee)
THE WEB
Three essential technologies:
 a system of globally unique identifiers for
resources: uniform resource locator ( URL);
 the publishing language HyperText Markup
Language (HTML);
 the Hypertext Transfer Protocol ( HTTP).
Source: T. Berner s Lee, Weaving the Web (1999)
URL
 Each Internet URL (e.g. www.google.com)
corresponds to an IP address (173.194.44.49).
 Let’s try!
THE WEB
WWW
Hypertext idea
+
Internet protocols
- TCP/IP (early70)
- DNS (early 80)
+
HTTP
HTML
URL
BROWSER
(since
1990-91)
DIGITAL MEDIA HISTORY: 1960-2000
 1969 DOD’s ARPAnet, predecessor of the Internet
 1970s Email is developed
 1976 Steve Jobs and Steve Wozniak, co -founders of Apple
Computer, Inc.
 1981 IBM PC is introduced
 1982 CDs are introduced
 1985 Microsoft Windows is launched
 1989 Compaq laptop computer is launched
 1991 Tim Berners-Lee invents the World Wide Web
 1993 Marc Andreessen creates predecessor to Netscape
browser
 1995 Amazon.com launches online shopping
 1997 DVDs replace VHS format
NETWORK TOPOGRAPHY
Some examples: 1) traf fic control systems; 2) the Internet; 3) bitTorrent
2 LOGICS
WEB EVOLUTION
 Web 1.0 – Connecting information
 Web 2.0 – Connecting people
 Web 3.0 – Connecting the physical world
Web 1.0 – Connecting information
Try to use
the
Internet
archive:
Wayback
machine
https://arc
hive.org/w
eb/
Web 2.0 – Connecting people (2004)
“Is all about harnessing
collective intelligence using the
web as a Platform” (Tim
O’Reilly, 2004)
es. Google, Amazon, Wikipedia,
eBay, craigslist, YouTube,
Facebook and Twitter.
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Web 2.0 – o’reilly (2005)
Web 2.0 is the network as platform, spanning all
connected devices.
Web 2.0 applications are those that make the most of the
intrinsic advantages of that platform:
 delivering software as a continually -updated service that
gets better the more people use it;
 consuming and remixing data from multiple sources
including individual users, while providing their own data
and services in a form that allows remixing by others;
 creating network effects through an “architecture of
participation”;
going beyond the page metaphor of Web 1.0 to deliver
rich user experiences.
WEB 2.0
Users add value
Examples?
WEB 2.0: THE POWER OF REVIEWS
TAGGING
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WEB 1.0 VS WEB 2.0?
 Tim Berners-Lee: "Web 1.0 was all about connecting
people. It was an interactive space, and I think Web 2.0
is of course a piece of jargon, nobody even knows what it
means. If Web 2.0 for you is blogs and wikis, then that is
people to people. But that was what the Web was
supposed to be all along.” (2006)
 “The essential difference between Web 1.0 and Web 2.0
is that content creators were few in Web 1.0 with the vast
majority of users simply acting as consumers of content,
while any participant can be a content creator in Web 2.0
and numerous technological aids have been created to
maximize the potential for content creation. (Cormode
and Krishnamurthy, 2008)
THE COMPUTER FOR THE 21ST CENTURY
M. Weiser, 1991
 Invisible technology
 Ubiquitous computing vs virtual reality?
 Examples?
Web 3.0 – Connecting the physical world
The Web meets the World
Some traits:
Real time
Mobile
Sentient
Social
 A video (Intel)
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Web squared (Battelle, o’reilly, 2009)
 The smartphone revolution has moved the
Web from our desks to our pockets.
 Collective intelligence applications are no
longer being driven solely by humans typing
on keyboards but, increasingly, by sensors.
 Our phones and cameras are being turned
into eyes and ears for applications; motion
and location sensors tell where we are, what
we’re looking at, and how fast we’re moving.
Source:
http://www.web2summit.com/web2009/public/sched
ule/detail/10194
WEB EVOLUTION
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WEB EVOLUTION
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