# Intelligent Systems

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```					CS101 Introduction to Computing

Lecture 34
Intelligent Systems

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During the last lecture …
(Graphics & Animation)
•   We became familiar with the role that
graphics and animations play in computing

•   We discussed how graphics & animation are
displayed

•   We also looked at several formats used for
storing graphics and animation
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Computer Graphics
• Images created with the help of computers

• 2-D and 3-D (displayed on a 2-D screen but in
such a way that they give an illusion of depth)

• Used for scientific research, artistic expression,
or for industrial applications

• Graphics have made the computer interfaces
more intuitive by removing the need to
memorize commands                        3
Displaying Images
• Most all computer displays consist of a grid of
tiny pixels arranged in a regular grid of rows
and columns

• Images are displayed by assigning different
colors to the pixels located in the desired
portion of the computer display

• Let’s discuss the pixel a bit more …
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Pixel
• The smallest image forming element on a
computer display

• The computer display is made up of a regular
grid of these pixels

• The computer has the capability of assigning
any color to any of the individual pixels on the
display

• Let’s now see how the computer displays a
square                                    5
Pixel Colors (1)
• The color of each pixel is generally represented
in the form a triplet

• In a popular scheme – the RGB scheme – each
part of the triplet represents the intensity of one
of out of three primary colors: red, green, blue

• Often, the intensity of each color is represented
with a byte, resulting in 256x256x256 (16+
million) unique color combinations            6
Color Mapping (1)
• Instead of letting each pixel assume one out of
16 million possible colors, only a limited number
of colors – called the platelet – are allowed

• For example, the platelet may be restricted to
256 colors (requiring 1 byte/pixel instead of 3)

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Dithering
• In this scheme, pixels of alternating colors are
used to simulate a color that is not present in
the platelet

• For example, red and green pixels can be
alternated to give the impression of bright
yellow

• The quality of the displayed image is poorer
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Aliasing
• The computer screen consists of square-ish
pixels arranged in a fixed grid

• At times, when a diagonal line is drawn on this
grid, it looks more like a staircase, instead of a
straight line

• This effect – called aliasing – can be managed
by reducing the size of pixels
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Anti-Aliasing (1)
• Anti-aliasing is another technique used for
managing the ‘staircase’ effect

• Let’s say that we need to draw a white straight-
line such that it overlaps 60% with one pixel,
and 40% with another initially, and near the
end, 58%, 41%, and 1%, respectively, with
three pixels

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Vector or Object-Oriented Graphics
• Treats everything that is drawn as an object

• Objects retain their identity after they are drawn

• These objects can later be easily moved,
stretched, duplicated, deleted, etc

• Are resolution independent

• Relatively small file size

• Examples: swf, svg, wmf, ps                  11
Bit-Mapped or Raster Graphics
• Treats everything that is drawn as a bit-map

• If an object is drawn on top of another, it is
difficult to move just one of them while leaving
the other untouched

• Changing the resolution often requires
considerable touch-up work

• Relatively large file size

• Examples: gif, jpg, bmp                     12
3-D Graphics (1)
• Flat images enhanced to impart the illusion of
depth

• We perceive the world and the objects in it in 3-
D - breadth, width, depth - although the images
formed on the retinas of our eyes are 2-D

• The secret of 3-D perception: stereo vision

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3-D Rendering
• The process of converting information about 3-
D objects into a bit-map that can be displayed
on a 2-D computer display

• Computationally, very expensive!

• Steps:
– Draw the wire-frame (skeleton, made with thin lines)
– Fill with colors, textures, patterns
Animation
• Graphics in motion, e.g. cartoons

• Illusion of motion is created by showing the
viewer a sequence of still images, rapidly

• Drawing those images - each slightly different
from the previous one - used to be quite tedious
work

• Computers have helped in cutting down some
of the tediousness                      15
Tweening (2)
• This process of creating these in-between
images from key images is called in-betweening
(or tweening for short)

• The simplest algorithm for tweening calculates
the position of a particular segment of an image
by calculating the average of the positions of
that same image segment belonging to
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Today’s Goals:
(Intelligent Systems)
•   To become familiar with the distinguishing
features of intelligent systems with respect to
other software systems

•   To become able to appreciate the role of
intelligent systems in scientific, business and
consumer applications

•   To look at several techniques for designing
intelligent systems
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(Artificial) Intelligent Systems
• SW programs or SW/HW systems designed to
that mimic some aspect of human thought

• One can debate endlessly about whether a
certain system is intelligent or not

• But to my mind, the key criterion is evolution: it
is intelligent if it can learn (even if only a limited
sense) and get better with time                   18
Not a Suitable Hammer for All Nails!
if the nature of computations required in a

or there are too many exceptions to the
rules

or known algorithms are too complex or
inefficient

then AI has the potential of offering an
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acceptable solution
Selected Applications
• Games: Chess, SimCity

• Image recognition

• Medical diagnosis

• Robots

Sub-Categories of AI
• Expert systems
– Systems that, in some limited sense, can
replace an expert

• Robotics

• Natural language processing
– Teaching computers to understand human
language, spoken as well as written

• Computer vision                              21
Selected Techniques
• Artificial neural networks

• Genetic algorithms

• Rule-based systems

• Fuzzy logic

Many times, any one of them can solve the problem at
hand, but at others, only the right one will do. Therefore,
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it is important to have some appreciation of them all
Neural Networks (1)
• Original inspiration was the human brain;
emphasis now on usefulness as a
computational tool

• Many useful NN paradigms, but scope of
today's discussion limited to the feed-forward

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Neural Networks (2)
• Feed-forward Network:
– It is a layered structure consisting of a number of
homogeneous and simple (but nonlinear)
processing elements

– All processing is local to a processing element and
is asynchronous

• During training the FN is forced to adjust its
parameters so that its response to input data
becomes closer to the desired response
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Genetic Algorithms (1)
• Based on Darwin's evolutionary principle of
‘survival of the fittest’

• GAs require the ability to recognize a good
solution, but not how to get to that solution

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Genetic Algorithms (2)
• The procedure:
– An initial set of random solutions is ranked in terms
of ability to solve the problem at hand
– The best solutions are then cross-bred and mutated
to form a new set
– The ranking and formation of new solutions is
continued until a good enough solution is found or
…

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Rule-based Systems (1)
• Based on the principles of the logical reasoning
ability of humans

• Components of an RBS:
– Rule-base
– Working memory
– Rule interpreter

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Rule-based Systems (2)
• The design process:

– An RBS engineer interviews the expert to acquire
the comprehensive set of heuristics that covers the
situations that may occur in a given domain

– This set is then encoded in the form of IF-THEN
structures to form the required RBS

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Fuzzy Logic (1)
• Based on the principles of the approximate
reasoning faculty that humans use when faced
with linguistic ambiguity

• The inputs and outputs of a fuzzy system are
precise, only the reasoning is approximate

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Fuzzy Logic (2)
• Parts of the knowledge-base of a fuzzy system:
– Fuzzy rules
– Fuzzy sets

• The output of a fuzzy system is computed by
using:
– The MIN-MAX technique for combining fuzzy rules
– The centroid method for defuzzification

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Now we know about a few techniques

Let’s now consider the situation when we
are given a particular problem and asked
to find an AI solution to that problem.

How do we determine the right technique
for that particular problem?

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Selection of an Appropriate AI Technique
• A given problem can be solved in several ways

• Even if 2 techniques produce solutions of a
similar quality, matching the right technique to a
problem can save on time & resources

• Characteristics of an optimal technique:
– The solution contains all of the required information
– The solution meets all other necessary criteria
– The solution uses all of the available (useful)
knowledge                                         32
How do we determine the
suitability of a particular AI
We look at the task’s requirements and then
see which technique fulfils those requirements
more completely – the one which does, is the
one we use!

Here are a few aspects of the task and the
techniques that we need to be aware off …
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• Accuracy
• Explainability
• Response speed
• Scalability
• Learning curve
• Compactness
• Tolerance for complexity
• Flexibility
• Embedability     • Tolerance for noise in data
• Ease of use      • Tolerance for sparse data
• Independence from experts
• Development speed
• Computing ease          34
in action!
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Credit Card Issuance (1)
• Challenge. Increase the acceptance rate of
card applicants who will turn out to be good
credit risks

• Inputs. Applicant's personal and financial
profiles

• Output. Estimated yearly loss if application is
accepted
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Credit Card Issuance (2)
• Expert knowledge. Some rules of thumb are
available

• Data. Profiles & loss data available for 1+
million applicants

• Suitable technique?

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Determination of the Optimal Drug Dosage (1)

• Challenge. Warn the physician if she prescribes
a dosage which is either too high or too low

• Inputs. Patient's medical record.
Pharmaceutical drug dosage instructions

• Output. Warning along with reasons for the
warning

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Determination of the Optimal Drug Dosage (2)

• Data. Medical records of thousands of patients.
Drug dosage instructions on dozens of
medicines

• Suitable technique?

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Prediction of Airline Cabin Crew's Preferences (1)

• Challenge. Predict the future base/status
preferences of the cabin crew of an airline. The
predicted preferences will be used by the airline
for forecasting its staffing and training
requirements

• Inputs. Crew's personal profiles. Preference
history. Other data.

• Output. Predicted preference card for a date
one year in the future                     40
Prediction of Airline Cabin Crew's Preferences (2)

• Expert knowledge. Some rules of thumb are
available

• Data. Available for the last four years for 8000
crew members

• Suitable technique?

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The Right Technique

• Selection of the right AI technique requires
intimate knowledge about the problem as well
as the techniques under consideration

• Real problems may require a combination of
techniques (AI and/or non-AI) for an optimal
solution

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A few more areas of AI
applications

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Robotics
• Automatic machines that perform various tasks
that were previously done by humans

• Example:
– Pilot-less combat airplanes
– Land-mine hunters
– Autonomous vacuum-cleaners

• Components: Body structure, actuators, power-
source, sensors, controller (the AI-based part)
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Autonomous Web Agents (1)
• Also known as mobile agents, softbots

• Computer program that performs various
actions continuously, autonomously on behalf
of their principal!

• Key component of the Semantic Web of
tomorrow

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Autonomous Web Agents (2)
• Multi-agent communities are being developed in
which agents meet and represent the interests
of their principals in negotiations or
collaborations. Example:

– Agents of a patient and a doctor get together to
negotiate and select a mutually agreeable time,
cost

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Decision Support Systems
• Interactive software designed to improve the
decision-making capability of their users

• Utilize historical data, models to solve problems

• The do not make decisions - just assist in the
process

• They provide decision-makers with information
via easy to manage reports, what-if scenarios,
and graphics                               47
The Future?
• Get ready to see robots playing a bigger role in
our daily lives
– Robots will gradually move out of the industrial
world and into our daily life, similar to the way
computers did in the 80’s

• Decision support systems will become a bigger
part of the professional life of doctors,
managers, marketers, etc

• Autonomous land, air, sea vehicles controlled
from 1000’s of miles away from the war zone
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Today’s Summary:
Intelligent Systems
•   We looked at the distinguishing features of
intelligent systems w.r.t. other software
systems

•   We looked at the role of intelligent systems in
applications

•   We discussed several techniques for
designing intelligent systems             49
Next Lecture:
(Data Management)
• To become familiar with the issues and
problems related to data-intensive computing

• To become able to appreciate data
management concepts and their evolution over
the years

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