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1、Artificial Intelligence Introduction,Donghui Wang AI InstituteZJU 2014.02,Contents,Whats AI? The history of AI The state of the art ML: What and why?,Whats AI?,Whats AI?,“We call ourselves Homo sapiens man the wise because our intelligence is so important to us. For thousands of years, we have tried
2、 to understand how we think; that is, how a mere handful of matter can perceive, understand, predict, and manipulate a world far larger and more complicated than itself. “ -Artificial Intelligence The field of artificial intelligence, or AI, goes further still: it attempts not just to understand but
3、 also to build intelligent entities.,Whats AI?,Hollywood movies The Terminator The Matrix iRobot Scientific research four approaches,Whats AI?,Hollywood movies: Mostly about androids, humanoids, and robots Can speak, see, think, act like human behavior Can feel human emotions Can create new things,W
4、hats AI?,Whats AI?,Acting humanly: The Turing Test approach The Turing Test, proposed by Alan Turing(1950), was designed to provide a satisfactory operational definition of intelligence. A computer passes the test if a human interrogator, after posing some written questions, cannot tell whether the
5、written responses come from a person or from a computer. Total Turing Test Natural language processing Knowledge representation Automated reasoning Machine learning Computer vision robotics,We dont want to make machines that fly so exactly like pigeons that they can fool even other pigeons.,Whats AI
6、?,Thinking humanly: The cognitive modeling approach To get a sufficiently precise theory of the mind and build a program thinks like a human. How humans think? Introspection Psychological experiments Brain imaging The interdisciplinary field of cognitive science brings together computer models from
7、AI and experimental techniques from psychology to construct precise and testable theories of the human mind. In the early days of AI there was often confusion between the approaches: an author would argue that an algorithm performs well on a task and that it is therefore a good model of human perfor
8、mance, or vice versa.,Whats AI?,Thinking rationally: The “laws of thought” approach There are some laws of thought to govern the operation of the mind: logic Aristotles syllogisms Two main obstacles to this approach: it is not easy to take informal knowledge and state it in the formal terms required
9、 by logical notation, particularly when the knowledge is less than 100% certain. there is a big difference between solving a problem “in principle“ and solving it in practice.,Whats AI?,Acting rationally: The rational agent approach Computer agents operate autonomously, perceive their environment, p
10、ersist over a prolonged time period, adopt to change, and create and pursue goals. A rational agent is one that acts so as to achieve the best outcome or, when there is uncertainty, the best expected outcome. Acting rationally Thinking rationally Simple reflex action,The history of AI,The history of
11、 AI,The gestation of artificial intelligence (19431955) The birth of artificial intelligence (1956) Early enthusiasm, great expectations (19521969) A dose of reality (19661973) Knowledge-based systems: The key to power? (19691979) AI becomes an industry (1980present) The return of neural networks (1
12、986present) AI adopts the scientific method (1987present) The emergence of intelligent agents (1995present) The availability of very large data sets (2001present),The history of AI,Strong AI and weak AI Strong AI is artificial intelligence that matches or exceeds human intelligence - the intelligenc
13、e of a machine that can successfully perform any intellectual task that a human being can. Weak AI (also called narrow AI or applied AI): the use of software to study or accomplish specific problem solving or reasoning tasks. Weak AI, in contrast to strong AI, does not attempt to simulate the full r
14、ange of human cognitive abilities.,The state of the art,The state of the art,What can AI do today?,The state of the art,Game playing Deep Blue by IBM brute force computing power massively parallel, RS/6000 SP Thin P2SC-based system with 30 nodes chess playing program was written in C and ran under t
15、he AIX operating system typically search to a depth of between six and eight moves to a maximum of twenty or even more moves in some situations.,Garry Kasparov and Deep Blue. 1997.,The state of the art,Game playing IBM Watson: Automatic Open-Domain Question Answering (2011),Given Rich Natural Langua
16、ge Questions Over a Broad Domain of Knowledge Deliver Precise Answers: Determine what is being asked & give precise response Accurate Confidences: Determine likelihood answer is correct Consumable Justifications: Explain why the answer is right Fast Response Time: Precision & Confidence in 3 seconds,Jeopardy!,The state of the art,Game playing DeepQA: NLP+ML+Reasoning Algorithms.,. . .,Answer Scoring,Models,Answer & Confidence,Question,Evidence S
