Title: Common Sense and Artificial Intelligence
1Common Sense and Artificial Intelligence
- Pradyumna Kumar ReddyJayanth Tadinada
- Prithvi Raj KanakamSatish Kumar
GugulothDevashish Sethia
2It is way past 2001 Where the hell is HAL?
3The Goals of Artificial Intelligence
- The need to reconsider the goals of AI
- Mental Amplification
- Thanks to engineering, we can travel faster and
farther than our muscles can take us, see things
we cant otherwise see, talk louder than our
lungs can shout.
4Expert Systems
- Our system Some diagnosis expert system like
MYCIN - The Patient An old rusted car in the back yard
- Question Answer session with the expert system
- Are there spots on the body? YES
- Are there more spots on the trunk than anywhere
else? YES - What color are the spots? REDDISH BROWN
- Diagnosis The car has measles
- Degree of confidence HIGH
Example taken from Google Techtalk by Doug Lenat,
may 2006
5Expert Systems (cont.)
- Our system An intelligent car loan approval
system - Question Answer session with the expert system
- Date of Birth 1989
- Time spent at current job 19 YEARS
- Result Loan approved
Example taken from Google Techtalk by Doug Lenat,
May 2006
6Expert Systems (cont.)
- So why do the expert systems have this
problem? - Because they dont have common sense
- The expert systems only know equations and
variables.
7Search
- Is the Eiffel tower taller than the Taj Mahal?
- Cannot combine knowledge it already has access
to. - Why cant the search engine do the simple math
and give us the answer - Lack of common sense
-
8Natural Language Processing
- The police watched demonstrators...
because they feared violence. because they
advocated violence. - Mary and Sue are sisters.Mary and Sue are
mothers. - George Burns My aunt is in the hospital, I went
to see her today, and took her flowers.Gracie
Allen George, Thats terrible! You should have
brought her flowers.
Example taken from Google Techtalk by Doug Lenat,
may 2006
9ASSUME OUR COMPUTER NOW HAS Common Sense
10Search
Query someone smiling Caption A
mother helping her child take her first step
When you are happy, you smile You become happy
when someone you love accomplishes a
milestone Taking ones first step is a
milestone Parents love their children
11Search
- Query Government buildings damaged in
terrorist events in Beirut between 1990 and
2001. - Document 1993 pipe bombing of Frances embassy
in Lebanon
Beirut is in Lebanon Embassies are govt.
buildings 1993 is in the 1990s If there was a
pipe bombing, then it is mostly a terrorist
attack and not an accident etc.
Example taken from Google Techtalk by Doug Lenat,
may 2006
12Natural Language Processing
- The police watched demonstrators...
because they feared violence. because they
advocated violence. - Mary and Sue are sisters.Mary and Sue are
mothers. - George Burns My aunt is in the hospital, I went
to see her today, and took her flowers.Gracie
Allen George, Thats terrible! You should have
brought her flowers.
Example taken from Google Techtalk by Doug Lenat,
may 2006
13So How do we implement Common Sense?
14What is this Knowledge?
- Millions of facts, rules of thumb etc.
- Represented as sentences in some language.
- If the language is Logic, then computers can do
deductive reasoning automatically. - This representation of a set of concepts within
a domain and the relationships between those
concepts is called Ontology - The sentences are expressed in formal logic
notation. - The words and the logic sentences about them
are called Formal Ontology
15Hierarchy in Ontology
16Predicate Calculus Representation
Parents love their children This can be
represented as (ForAll ?P (ForAll ?C
(implies (and (isa ?P Person)
(child ?P ?C)) (loves ?P ?C))))) For all P,
For all C, P is a person AND C is a child of P
implies P loves C
17Reasoning Using Logic
Examples Simple (isa Socrates Man) (ForAll
?x (implies (isa ?x Man) (isa ?x Mortal))) (isa
Socrates Mortal) gtYes Harder Using general
and specific knowledge Can a can can-can? gt No
18Cyc
- Cyc is an AI project that attempts to assemble a
comprehensive ontology and knowledge of everyday
common sense knowledge. - Its goal is to enable AI applications to perform
human like reasoning. - The project was started by CYcorp, a Texas based
company. - All the aforementioned features were
incorporated in Cyc.
19Cyc
- Cyc has a huge knowledge base which it uses for
reasoning. - Contains
- 15,000 predicates
- 300,000 concepts
- 3,200,000 assertions
- All these predicates, concepts and assertions
are arranged in numerous ontologies.
20Cyc Features
- Uncertain Results
- Query who had the motive for the assassination
of Rafik Hariri? - Since the case is still an unsolved political
mystery, there is no way we can ever get the
answer. - In cases like these Cyc returns the various view
points, quoting the sources from which it built
its inferences. - For the above query, it gives two view points
- USA and Israel as quoted from a editorial in
Al Jazeera - Syria as quoted from a news report from CNN
Example taken from Google Techtalk by Doug Lenat,
may 2006
21Cyc Features (cont.)
- It uses Google as the search engine in the
background. - It filters results according to the context of
the query. - For example, if we search for assassination of
Rafik Hariri, then it omits results which have a
time stamp before that of the assassination date.
22Cyc Features (cont.)
- Qualitative Queries
- Query Was Bill Clinton a good President of the
United States? - In cases like these, Cyc returns the results in
a pros and cons type and leave it to the user to
make a conclusion. - Queries With No Answer
- Query At this instance of time, Is Alice
inhaling or Exhaling? - The Cyc system is intelligent enough to figure
out queries which can never be answered correctly.
Example taken from Google Techtalk by Doug Lenat,
may 2006
23The Dream
- The ultimate goal is to build enough common
sense into the Cyc system such that it can
understand Natural Language. - Once it understands Natural Language, all the
system has to do is crawl through all the online
material and learn new common sense rules and
evolve. - This two step process of building common sense
and using machine learning techniques to learn
new things will make the Cyc system an infinite
source of knowledge.
24Drawbacks
- There is no single Ontology that works in all
cases. - Although Cyc is able to simulate common sense it
cannot distinguish between facts and fiction. - In Natural Language Processing there is no way
the Cyc system can figure out if a particular
word is used in the normal sense or in the
sarcastic sense. - Adding knowledge is a very tedious process.
25References
- Marvin Minsky, Why People Think Computers Cant,
AI Magazine, vol. 3 no. 4, Fall 1982. - Douglas B Lenat, Keynote address computers vs
common sense, Proceedings of the 1991 ACM SIGMOD
international conference on Management of data,
April 1991. - Douglas B Lenat, R V Guha, Karen Pittman, Dexter
Pratt and Mary Shepherd, Cyc toward programs
with common sense, Communications of the ACM,
1990. - Douglas B Lenat, George Miller and Toshio Yokoi,
CYC, WordNet, and EDR critiques and responses,
Communications of the ACM, 1995. - Talk by Douglas Lenat, Google techtalks, May 2006