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SHRDLU was an early natural language understanding computer program, developed by Terry Winograd at MIT from 1968-1970. It was written in the Micro Planner and Lisp programming language on the DEC PDP-6 computer and a DEC graphics terminal. Later additions were made at the computer graphics labs at the University of Utah, adding a full 3D rendering of SHRDLU's "world". Natural Language Processing (NLP) is a subfield of artificial intelligence and linguistics. ...
A computer program is a collection of instructions that describe a task, or set of tasks, to be carried out by a computer. ...
Terry A. Winograd Terry Allen Winograd (born February 24, 1946) is a professor of computer science at Stanford University. ...
Mapúa Institute of Technology (MIT, MapúaTech or simply Mapúa) is a private, non-sectarian, Filipino tertiary institute located in Intramuros, Manila. ...
Year 1968 (MCMLXVIII) was a leap year starting on Monday (link will display full calendar) of the 1968 Gregorian calendar. ...
1970 (MCMLXX) was a common year starting on Thursday. ...
Planner (often seen in publications as PLANNER) is a programming language designed by Carl Hewitt at MIT, and first published in 1969. ...
Lisp is a family of computer programming languages with a long history and a distinctive fully-parenthesized syntax. ...
The DEC logo Digital Equipment Corporation was a pioneering American company in the computer industry. ...
The PDP-6 (Programmed Data Processor-6) was a computer model developed by Digital Equipment Corporation (DEC) in 1963. ...
A computer terminal is an electronic or electromechanical hardware device that is used for entering data into, and displaying data from, a computer or a computing system. ...
Computer graphics is a sub-field of computer science and is concerned with digitally synthesizing and manipulating visual content. ...
The University of Utah (also The U or the U of U or the UU) is a public university in Salt Lake City, Utah. ...
Winograd later distanced himself from SHRDLU and the field of AI, believing SHRDLU a research dead end.[citation needed]
The name SHRDLU was derived from ETAOIN SHRDLU, the arrangement of the alpha keys on a Linotype machine, arranged in descending order of usage frequency in English. // ETAOIN SHRDLU (often pronounced et-ee-oin shurd-loo) is the approximate order of frequency of the twelve most commonly used letters in the English language, best known as a nonsense phrase that sometimes appeared in print in the days of hot type publishing due to a custom of Linotype...
It has been suggested that this article or section be merged with Linotype. ...
Functionality
SHRDLU allowed user interaction using English terms. The user instructed SHRDLU to move various objects around in a small "blocks world" containing various basic objects: blocks, cones, balls, etc. What made SHRDLU unique was the combination of four simple ideas that added up to make the simulation of "understanding" far more convincing.
One was that SHRDLU's world was so simple that the entire set of objects and locations could be described by including as few as perhaps 50 words, nouns like "block" and "cone", verbs like "place on" and "move to", and adjectives like "big" and "blue". The possible combinations of these basic language building blocks were quite simple, and the program was fairly adept at figuring out what the user meant.
SHRDLU also included a basic memory to supply context. One could ask SHRDLU to "put the green cone on the red block" and then "take the cone off"; "the cone" would be taken to mean the cone one had just talked about. SHRDLU could search back further to find the proper context in most cases when additional adjectives were supplied. One could also ask questions about the history, for instance one could ask "did you pick up anything before the cone?"
A side effect of this memory, and the original rules SHRDLU was supplied with, is that the program could answer questions about what was possible in the world and what was not. For instance, SHRDLU would deduce that blocks could be stacked by looking for examples, but would realize that triangles couldn't be stacked, after having tried it. The "world" contained basic physics to make blocks fall over, independent of the language parser. A magnet levitating above a high-temperature superconductor demonstrates the Meissner effect. ...
A parser is a computer program or a component of a program that analyses the grammatical structure of an input, with respect to a given formal grammar, a process known as parsing. ...
Finally, SHRDLU could also remember names given to objects, or arrangements of them. For instance one could say "a steeple is a small triangle on top of a tall rectangle"; SHRDLU could then answer questions about steeples in the blocks world, and build new ones.
Excerpt Here is an extract from a famous demonstration of SHRDLU (with messages converted from their original upper case for ease of reading): Person: Pick up a big red block.
Computer: OK.
Person: Grasp the pyramid.
Computer: I don't understand which pyramid you mean.
Person (changing their mind): Find a block which is taller than the one you are holding and put it into the box.
Computer: By "it", I assume you mean the block which is taller than the one I am holding.
Computer: OK.
Person: What does the box contain?
Computer: The blue pyramid and the blue block.
Person: What is the pyramid supported by?
Computer: The box.
Person: How many blocks are not in the box?
Computer: Four of them.
Person: Is at least one of them narrower than the one which I told you to pick up?
Computer: Yes, the red cube.
etc.
Consequences The result was a tremendously successful demonstration of AI. This led other AI researchers to excessive optimism which was soon lost when later systems attempted to deal with more realistic situations with real-world ambiguity and complexity. Continuing efforts in the original SHRDLU stream have tended to focus on providing the program with considerably more information from which it can draw conclusions, leading to efforts like Cyc. Garry Kasparov playing against Deep Blue, the first machine to win a chess game against a reigning world champion. ...
Cyc is an artificial intelligence project that attempts to assemble a comprehensive ontology and database of everyday common sense knowledge, with the goal of enabling AI applications to perform human-like reasoning. ...
References - Procedures as a Representation for Data in a Computer Program for Understanding Natural Language. MIT AI Technical Report 235, February 1971
See also Planner (often seen in publications as PLANNER) is a programming language designed by Carl Hewitt at MIT, and first published in 1969. ...
External links - SHRDLU - Terry Winograd's SHRDLU page, includes source code
- Conversation with SHRDLU - includes an annotated version of the sample conversation found above
- SHRDLU resurrection - re-written versions of SHRDLU, including a Java3D version
- shrdlu - an affectionate chronicle - The 50th Anniversary memoir of the National Press Club, published in 1958
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