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PUBLICATIONS Room NE43-908 ARTIFICIAL INTELLIGENCE LABORATORY 545 TECHNOLOGY SQUARE CAMBRIDGE, MA 02139

IJCAI Participants:

This is a currsnt listing of availabls MIT Al Lab publications. If you wish to order any, please enclose completed order form and exact payment in the pre-addressed envelope and drop in any Institute Interdepartmental mailbox. Your publications will be mailed to you as soon as possible.

If you prefer to pick up your order while you are at IJCAI, the Publications Office will be open between 12:15PM and I:3OPM each day of the conference.

Since storage space is limited (generally we stock about 100 copies of each publication], it is likely that some, if not all, of your order will be mailed to you at a later date after supplies are replenished. Reports assigned an "AD" number are available from the National Technical Information Service, Operations Division, Springfield, Virginia 22151 in both microfiche and paper copies. PAGPtI

86 Design of the Hand, Marvin Minsky, August 1965, MAC-M-258 (see Al Memo 267) ($.90)

90 MIOAS, Petsr Samson, Oct. 1968. Revised version of MAC-M-279, Oct 1965 (see A.I. Memos 179, 214). ($1.70)

116 POP-6 LISP (LISP __3), January 1967, Rsvissd April 1967 (see A.I. Memo 190 and MACLISP Reference Manual, O. Moon et al, Project MAC). ($1.30) Thia ie a mosaic description of PDP-6 LISP, intended for readers familiar with ths LISP 1.5 Programmsr's Manual or who have used LISP on soms other computer.

122 Remarks on Correlation Tracking, Marvin Minsky, March 1967. ($.90)

123 Computer Tracking of Eye Motions, Marvin Minsky, Seymour Papert, March 1967 (ses A.I. Memo 253). ($.90) This memo gives reasons why the Artificial Intelligence group is developing methods for on-line tracking of human eye movements, resume of results to date and the next steps. 126 A Quick Fail-Safe Procedure for Determining whether the GCD of 2 Polynomials is 1, Joel Moses, March 1967, MAC-M-345. ($.90)

147A DDT Reference Manual, Eric Osman, Sept. 1971. ($2.10) This memo describes the version of DOT used as the command level of the Al Laboratory Time Sharing System (ITS].

154 The Artificial Intelligence of Hubert L. Dreyfus; A Budget of Fallacies, Seymour Papert, Jan. 1968. ($2.10) This paper reviews the earlier writing of Hubert Dreyfus on Artificial Intelligence. It reveals many fallacies in Dreyfus' thinking.

155 A Left to Right then Right to Left Pareing Algorithm, William Martin, Feb. 1968.

160 Focusing, B.K.P. Horn, May 1968. ($1.70) This memo describes a method of automatically focusing the image dissector camera. The same method cen be used for distance measuring.

161 ITS 1.5 Reference Manual, D. Eastlake, R. Greenblatt, J. Holloway, T. Knight, S. Nelson, MAC-M-377. July 1969 (Revised form of ITS 1.4 Reference Manual, June 1968). (see Al Memos 147A, 238, 260A, 261A) ($2.60) 173 A Heuristic Program That Constructs Decision Trees, Patrick Winston, March 1969. Supposs there is a set of objecte, (A,8,...,Z), and a set of tests, (T1,T2,...,TN). When a test is applied to an object, the result is either T or F. Assume the tests may vary in cost and the objects may vary in probability of occurrence. One then hopes that an unknown object may be identified by applying a sequence of tests. The appropriate test at any point in the sequence in general should depend on the results of previous tests. The problem is to construct a good test scheme using ths test costs, ths probabilities of occurence, and a table of test outcomes. 174 The Greenblatt Chess Program, Richard Greenblatt, Donald Eastlake 111, Stephen Crocker, April 1969. (s.9o] Since mid-November 1966 a chess program has been under development at the Artificial Intelligence Laboratory of Project MAC at M.I.T. This paper describes ths stale of the program as of August 1967 and gives some of the details of the heuristics and algorithms employed. 178 The Image Dissector Eyes, B.K.P. Horn, August 1969. ($1.70) This is a collection of data on the construction, operation and performance of the two image dissector cameras. 180 The Integration of a Class of Special Functions with the Risch Algorithm, Joel Moses, MAC-M-421. ($.90) We indicate how to extend the Risch algorithm to handle a class of special functions defined in terms of integrals. Most of the integration machinery for this class of functions is similar to ths machinery in the algorithm which handles logarithms. A program embodying much of the extended integration algorithm has been written. It was used to check a table of integrals and

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it succeeded in finding some misprints in it.

184 Parsing Key Word Grammars, William Martin, MAC-M-395. ($.90) Key word grammars are defined to be the same as context free grammars, except that a production may specify a string of arbitrary symbols.

187 Form and Content in Computer Science, Marvin Minsky, December 1969; ACM 'Turing Lecture' August 1969. ($1.30) 191 Ai I. Bibliography, April 1970, updated later (FREE!) 194 Movie Memo, Michael Beeler, April 1970. This is intended as a brief explanationof how to use the Kodak movie camera in sync with a display.

199 The Function of FUNCTION in LISP, Joel Moses, June 1970. ($.90) A problem common to many powerful programming languages arisee when one hae to determine what values to assign to free variables in functions.

210 A User's Guide to the AX Group LISCOM LISP Compiler, Jeffrey P. Golden, December 1970. The operation of a version of a fast arithmetic LISP compiler for ITS on the PDP-10 i3discussed. 217 Computer Proofs of Limit Theorems, W.W. Bledsoe, Robert S. Boyer, W.H. Henneman, June 1971. ($.90) Some relatively simple concepts have been developed which when incorporated into existing automatic theorem proving programs (including those using resolution), enable them to prove sfficisntly a number of the limit theorems of Elementary calculus, including the theorem that differentiate functions are continuous.

218 Information Theory and the Game of Jotto, Michael Beeler, August 1971. The operation and use of a PDP-10 program for playing the word game JOTTO are described. The program works by making ths move which will give it the most information in the information-theoretic sense.

238 ITS Status Report, Donald Eastlake, April 1972. ($2.10) ITS is a time-shared operating system designed for the Artificial Intelligence Laboratory DEC PDP-10/PDP-6 installation and tailored to its special requirements. This status report described the design philosophy behind the ITS system, the hardwars and software facilities of the eyetem implemented with this philosophy, and some information on work currently in progreee or desirable in the near future.

239 HAKMEM, M. Beeler, R.W. Gosper, R. Schroeppel, February 1972. ($2.60) HAKMEM is a collection of 191 miscellaneous items, most of which are too short to justify documentation individually. Topics are related to computers, but range over number theory and several other branches of mathematics, games, programming techniquee, and electronic circuits. Items come from A. I. work, outside contributors, and computer folklore. "I keep HAKMEM in the bathroom, it'e great reading." - Knuth 240A 11SIM Reference Manual, (revised), Donald Eastlake, February 1972. A program that simulatss a Digital Equipment Corporation PDP-11 computer and many of its peripherals on the A.I. Laboratory Time Sharing System (ITS) is described from a user's reference point of view.

241 An A.I. Approach to English Morphemic Analysis, Terry Winograd, September 1971. This paper illustrates an approach toward understandingnatural language through the techniques of artificial intelligence.

246 A Computer Laboratory for ElementarySchools, Seymour Papert, October 1971 (LOGO Memo No. 1). ($.90) This is a research project on elementary education whose immediate objective is ths development of new methods and materiale for teaching in an environment of computers and

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computer-controlled devices. Longer term objectives are related to theories of cognitive processes and to conjectures about the possibility of producing much larger changes than are usually though possible in the expected intellectual achievement of children.

247 Teaching Children Thinking, Seymour Papert, October 1971 (LOGO Memo No. 2). ($1.30) Tho purpose of this essay is to present a grander vision of an educational system in which technology is used not in the form of machines for processing children but as something the child himself will learn to manipulate, to extend, to apply to projects, thereby gaining a greater and more articulate mastery of the world, a sense of the power of applied knowledge and a self-confidently realistic image of Nmself as an intellectual agent.

248 Twenty Things To Do With A Computer, Seymour Papert and Cynthia Solomon, June 1971 (LOGO Memo No. 3).

249 Teaching Children to be Mathematicians VS. Teaching About Mathematics, Seymour Papert, July 1971 (LOGO Memo No. 4). ($1.30] This essay is an attempt to explore some ways in which one might be able to put children in a better position to do mathematics rather than merely to learn about it.

252 Artificial Intelligence Progress Report, Marvin Minsky and Seymour Papert, January 1972. ($2.50). (Identical with pp. 129-324 of the 1971 Project MAC Progress Report VIU.) AD-754-820.

253 The Computer-Controlled Oculometer: A Prototype Interactive Eye Movement Tracking System, Matthew J. Hillsman, R. Wade Williams and John S. Roe, February 1972. (Originally published as a report to NASA in September 1970.] (£2.60)

254 MM: A Game-Playing Program, Seymour Papert and Cynthia Solomon, Feb. 1972 (LOGO Memo No. 5). (55.90) This note illustrates some ideas about how to initiate beginning students into the art of planning and writing a program complex enough to be considered a project rather than an exercise on using the languageor simple programming ideas.

255A Why Conniving Is Better Than Planning, Gerald Sussman and Drew McDermott, April 1972 (see also A.I. Memo 259). ($1.30) This paper is a critique of a computer programming language, Carl Hewitt's PLANNER, a formalism designed especially to cope with the problems that Artificial Intelligence encounters. It is our contention that the backtrack control structure that is the backbone of PLANNER is more of a hindrance in the solution of problems than a help. In particular, automatic backtracking encourages inefficient algorithms, conceals what is happening from the user, and misleads him with primitives having powerful names whose power is only superficial. An alternative, a programming language called CONNIVER which avoids these problems, is presented from the point of view of this critique.

259A THE CONNIVER REFERENCE MANUAL, Drew McDermott and Gerald Sussman, January 1974. AD-773-555. This manual is an introduction and reference the latest version of the Conniver programming language, an A. I. languagewith general control and data-base structures.

260A LOCK, Donald E. Eastlake, January 1974. ($.90) AD-773-920. LOCK is a miscellaneous utility program operating under the ITS system. It allows the user to easily and conveniently perform a variety of infrequently required tasks. Most of these relate to console input-output or the operationof the ITS system. 2BIA PEEK, Donald E. Eastlake, February 1974. AD-773-925. PEEK is a utility program designed to operate under the ITS time sharing system. It enables a user to monitor a variety of aspects of the time sharing system by providing periodically updated display output or periodic printed output to teletype or line printer.

264 Developing a Musical Ear: A New Experiment, Jeanne Bamberger, July 1972. (LOGO Memo No. 6)

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($.90) This is a report on some ideas we have been developing at M.I.T. for self-paced, independent music study. The aim of our approach is to nurture in students that enigmatic quality called musical — be it a musical ear or an individual's capacity to give a musical performance. 265 Infants in Children Stories-Toward a Model of Natural Language Comprehension, Garry S. Meyer, August 1972. We are interested here with understanding natural language in a very broad area. In particular how does one understand stories about infants? We propose a system which answers such questions by relating the story to background real world knowledge.

267 ManipulatorDesign Vignettes, Marvin Minsky, October 1972. ($1.30) This memo is about mechanical arms. The literature on robotics seems to be deficient in such discussions, perhaps because not enough sharp theoretical problems have been formulated to attract interest.

268 A Human Driented Logic for Automatic Theorem Proving, Arthur J. Nevins, October 1972. A deductive system is described which should replace the resolution principle as the primary instrument for proving theorems by computer.

273 The Little Robot System, David Silver, January 1973. ($.90) AO-773-929. The Little Robot System provides for the I.T.S. user a medium size four degree of freedom six axis robot which is controlled by the PDP-6 computer through the programming language LISP.

275 Differential Peceptrons, Martin Brooks, Jerrold Ginsparg, January 1973. AO-773-919. This paper shows that differential perceptrons are equivalent to perceptrons on the class of figures that fit exactly onto a sufficiently small square grid. 276 The Making of the Film, SOLAR CORONA, Michael Beeler, February 1973. (Film Memo No. 1.). ($.90) AD-773-928. The film SOLAR CORONA was made from data taken from August 14, 1969 through May 7, 1970, by OSO-VI, one of the Orbiting Satellite Observatories.

277 A Linguistics Oriented Programming Language, Vaughan R. Pratt, February 1973 AD-773- -566. A programming language for natural language processing programs is described.

278 D-SCRIPT: A ComputationalTheory of Descriptions, Robert C. Moore, February 1973. AD- -773-926. This paper describes D-SCRIPT a language representing knowledge in artifical intelligence programs.

279 Pretty-Printing, Converting List to Linear Structure, Ira Goldstein, February 1973. ($1.30) AD-773- -927. Pretty-printing is the conversion of list structure to a readable format. This paper outlines the computational problems encountered in such a task and documents the current algorithm in use.

280 Elementary Geometry Theorem Proving, Ira Goldstein, April 1973. ($1.70) AD-735-568. An elementary theorem prover for a small part of plane Euclidean geometry is presented. The purpose is to illustrate important problem solving concepts that naturally arise in building procedural models for mathematics.

282 Grammar for the People: Flowcharts of SHRDLU's Grammar, Andee Rubin, March 1973. ($1.30) The grammar which SHRDLU uses to parse sentences is outlined in a series of flowcharts which attempt to modularize and illuminate its structure. In addition, a short discussion of systematic grammar is included.

285 The Binford-Horn LINEFINDER, B.K.P. Horn, Revised December 1973. (Originally published as A.l.Vision Flash 18, July 1971). This paper briefly describes the processing performed in the course of producing a line drawing from an image obtained through an image dissector camera.

29Q Paterson's Worm, Michael Beeler, June 1973. ($.90) AD-775-351. A description of a mathematical

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idealization of the feeding pattern of a kind of worm is given.

UT: Telnet Reference Manual, Donald Eastlake, April 1974. ($.90) UT is a user telnet program designed to run under the ITS time sharing system. It implements the relatively recent ARPA negotiating protocol for telnet.

295 On Lightness, Berthold K.P. Horn, October 1973 (see Computer Graphics and Information Processing, December, 1974). ($2.10) (AD-773-569). The intensity at a point in an image is the product of the reflectance at the corresponding object point and the intensity of illumination at that point. We are able to perceive lightness, a quantity closely correlated with reflectance. How then do we eliminate the component due to illumination from the image on our retina? The two components of image intensity differ in their spatial distribution. A method is presented here which takes advantage of this to compute lightness from image intensity in a layered, parallel fashion.

296 An Essay on ths Primate Retina, David Marr, January 1974 (see Vision Research, 1974, 14, 1377- -1388). ($2.10) (AD-D34-482). This essay is considerably longer than the published version of the same theory, and is designed for readers who have only elementary knowledge of the retina.

298 Uses of Technology to Enhance Education, Seymour Papert, June 1973 (LOGO Memo 8). ($2.60) This paper is the substance of a proposal to the N.S.F. for support of research on children's thinking and elementary education.

300 Design Outline for Mini-Arms Based on Manipulator Technology, Carl R. Flatau, May 1973 (issued as A.I. Memo January 1974). ($1.70) AD-773-570. The design of small manipulators is an art requiring proficiency in diverse disciplines.

301 A Mechanical Arm Control System, Richard C. Waters, January 1974. (AD-AOO4-672). This paper describes a proposed mechanical arm control system, and some of the lines of thought which lead to the current design.

302 A Relaxation Approach to Splitting in an Automatic Theorem Prover, Arthur Nevins, January 1974. ($1.30) (AD-ADO4-269). The splitting of a problem into subproblems often involves the same variable appearing in more than one of the subproblems. This makes these subproblems dependent upon one another since a solution to one may not qualify as a solution to another. A two stage method of splitting is described which first obtains solutions by relaxing the dependency requirement and then attempts to reconcile solutions to different subproblems. 303 Plane Geometry Theorem Proving Using Forward Chaining, Arthur Nevins, January 1974. ($1.30) AO-AOO4-223. A computer program is described which operates on a subset of plane geometry.

304 Acceleration of Series, William Gosper, March 1974. (AD-A011B37). The convergence of infinite series can be accelerated by a suitable splitting of each term into two part3and then combining the second part of the n-th term with the first part of the (n+l)-th term to get a new series and leaving the first part of the first term as an "orphan." Repeating this process an infinite number of times, the series will often approach zero, and we obtain the series of orphans, which may convergefaster than the original series, heuristics for determining the splits are given. Various mathematical constants, orginally defined as series haying a term ratio which approaches 1, are accelerated into series having a term ratio less than 1.

306 A Framework for Representing Knowledge, Marvin Minsky, June 1974. (AD-AOll-1B8). ($2.10). (In Psychology of Computer Vision) This is a partial theory of thinking, combining a number of classical and modern concepts from psychology, linguistics, and A. I. Whenever one encounters a new situation (or makes a substantial change in one's viewpoint] he selects from memory a structure called a frame: a remembered framework to be adapted to fit reality by changing details as necessary-

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3QB Force Feedback in Precise Assembly Tasks, Hirochika Inoue, August 1974. (AD-ADII-369). ($1.30) This paper describes the execution of precise assembly tasks by a robot.

3D9 Commenting Proofs, James R. Geiser, Auguet 1974. ($.90). (AD-AOll-B3B). This paper constitutes a summary of a seminar entitled "Commenting Proofs" given at the A.I. Lab at M.I.T. during the Spring of 1974.

311 TORTIS: Toddler's Own Recursive Turtle Interpreter System, Radia Perlman, December 1974. (LOGO Memo No. 9) TORTIS is a device for preschool children to communicate with and program the turtle.

312 The Luxury of Necessity, Jeanne Bamberger, December 1974. (LOGO Memo N0.12) Posing a series of questions which point to fundamental issues underlying the LOGO music project, the paper describes some of the specific projects with which students have been working in an effort to probe these issues.

313 LOGO Manual, Hal Abelson, Nat Goodman, Lee Rudolph, December 1974. (LOGO Memo 7) ($2.10) This document describes the LOGO system implemented for the PDP 11/45 at the M.I.T. Artificial IntelligenceLaboratory.

314 What's In A Tune, Jeanne Bamberger, December 1974. [LOGO Memo 13) ($1.30) The work reported here began with two fundamental assumptions: 1) The perception of music is an activs process; it involves the individual in selecting, sorting, and grouping the features of the phenomena before her. 2) Individual differences in response to a potentially sensible melody rest heavily on just which features the individual has access to or is able to focus an.

315A A Glossary of PDPII LOGO Primitives, E. Paul Goldenberg, March 1975. (LDGO MEMO 16). ($1.30). This glossary was written for the purpose of providing a quick and concise yet accurate descripion of the primitives and special worde and characters of the March 18, 1975 PDP 11 implementation of the LOGO language. 319 Localization of Failures in Radio Circuits - A Study in Causal and Teleological Reasoning, Allen Brown, Gerald Sussman, December 1974. (AD-AOll-839].(51.30) This paper examines some methodologies for diagnosing correctly designed radio circuits which are failing to perform in the intended way because of some faulty component.

320 Velocity Space and the Geometry of Planetary Orbits, Harold Abelson, Andrea diSessa,Lee Rudolph, December 1974. (LOGO Memo 15) We develop a theory of orbits for the inverse-square central force law which differs considerablyfrom the usual deductive approach.

321 Model-Driven Geometry Theorem Prover, Shimon Ullman, May 1975. ($.70). ADA-021446. This paper describes a new Geometry Theorem Prover, which was implemented to illuminate some issues related to the use of models in theorem proving.

322 A Frame for Frames: Representing Knowledge for Recognition, Benjamin J. Kuipers, March 1975. (AD-AOl2-835). ($1.30). This paper presents a version of frames suitable for representing knowledge for a class of recognition problems.

323 Orienting Silicon Integrated Circuit Chips for Lead Bonding, Berthold K. P. Horn, January 1975. (In Computer Graphics and Information Processing, September, 1975). ($0.90). (ADA-021137). Will computers that see and understand what they see revolutionize industry by automating the part orientation and part inspection processes? There are two obstacles: the expense of computing and our feeble understanding of images. We believe these obstacles ars fast ending. To illustrate what can be done ws describe a working program that visually determines the position and orientation of silicon chips used in integratedcircuits.

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327 A Note on the Computation of Binocular Disparity in a Symbolic, Low-level Visual Processor, David Man-, December 1974. (AD-AOl2-393). ($0.90). The goals of the computation that extracts disparity from pairs of pictures of a scene are defined, and the constraints imposed upon that computation by the three-dimensional structure of the world are shown to be inadequate. A precise expression of the goals of the computation is possible in a low-level symbolic visual processor: the constraints translate in thie environment to pre-requisitss on the binding of disparity values to low-level symbols.

328 Heuristic Techniques in Computer Aided Circuit Analysis, Gerald Jay Sussman and Richard Matthew Stallman, March 1975. (ADA-02117T). We present EL, a new kind of circuit analysis program. Whereas other circuit analysis systems rely on classical, formal analysis techniques, EL employs heuristic "inspection" methods to solve rather complex DC bias circuits. These techniques also give EL the ability to explain any result in terms of its own qualitative reasoning processes.

329 Parsing Intensity Profiles, Tomas Lozano-Perez, May 1975. ($1.30). (ADA-021172). Much low-level vision work in Al deals with one-dimensional intensity profiles. This paper describes PROPAR, a system that allows a convenient and uniform mechanism for recognizing such profiles.

330 A Computational View Of The Skill Of Juggling, Howard Austin, December 1974. This research has as its basic premise the belief that physical and mental skills are highly similar, enough so in fact that computation paradigms such as the ones used in Artificial Intelligence research about predominantly mental skills can be usefuly extended to include physical skills.

331 Thesis Progress Report: A System For Representing and Using Real-World Knowledge, Scott E. Fahlman, May 1975. ($2.10). (ADA-02117B). This paper describes progress to date in the development of a system for representing various forms of real-world knowledge. The knowledge is stored in the form of a net of simple parallel processing elements, which allow certain types of deduction and set-intersection to be performed very quickly and easily.

332 Ideas about Management of Data Bases, Erik Sandewll, May 1975. (AD-AOl3-312). ($1.30). The paper advocates the need for systems which support maintenance of LISP-type data bases, and describes an experimental system of this kind, called OABA.

333 On the Detection of Light Sources, Shimon Ullman, May 1975. ($0.90). (AD-AO2l-136). The paper addresses the following problem: Given an array of light intensities obtained from some scene, find the light sources in the original scene. The following factors are discussed from the point of view of their relevance to light sources detection: The highest intensity in the scene, absolute intensity value, local and global contrast, comparison with the average intensity, and lightness computation. They are shown to be insufficient for explaining humans' ability to identify light sources in their visual field. Finally, a method for accomplishing the source detection task in the mondrian world is presented.

335 Image Intensity Understanding, Berthold K. P. Horn, August 1975. ($2.10). (ADA-021135). Image intensities have been processed traditionally without much regard to how they arise. Typically they are used only to segment an image into regions or to find edge-fragments. Image intensities do carry a great deal of useful information about three-dimensional aspects of objects and some initial attempts are made here to exploit this. An understanding of how images are formed and what determines the amount of light reflected from a point on an object to the viewer is vital to such a development. The gradient-space, popularized by Huffman and Mackworth is a helpful tool in this regard.

336 Teaching Teachers Logo, The Lesley Experiments, Howard Austin, April 1976. ($1.30). This research is concerned with the question of whether or not teachers who lack specialized backgrounds can adapt to and become proficient in the technically complex, philosophically sophisticated LOGO learning environment.

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337 Artificial Intelligence,Language and the Study of Knowledge, Ira Goldstein and Seymour Papert, July 1975, Revised March 1978. This paper studies the relationship of Artificial Intelligence to the study of language and the representation of the underlying knowledge which supports the comprehension process. It develops the view that intelligence is based on the ability to use large amounts of diverse kinds of knowledge in procedural ways, rather than on the possession of a few general and uniform principles. 338 The Art of Snaring Dragons, Harvey A. Cohen, November 1974, revised May 1975. (LOGO Memo IB). ($2.10). DRAGONS are formidable problems in elementary mechanics not amenable to solution by naive formula cranking.

339 Very Large Planner-type Data Bases, Drew V. McDermott, September 1975. (AO-A026- -370). This paper describes the implementation of a typical data-base manager for an Al language like Planner, Conniver, or QA4, and some proposed extensions for applications involving greater quantities of data than usual.

340 Early Processing of Visual Information, D. Marr, December 1975. (AD-AO2l-445). (In Philosophical Transactions of the Royal Society of London, Bj 275, 483-524, (1975). The article describes a symbolic approach to visual information processing, and sets out four principles that appear to govern the design of complex symbolic information processing systems. A computational theory of early visual information processing is presented, which extends to about the level of figure-ground separation. It includes a process-oriented theory of texture vision. Most of the theory has been implemented, and examples are shown of the analysis of several natural images.

341 Spatial Disposition of Axes in a Generalized Cylinder Representation of Objects that Do Not Encompass the Viewer, D. Marr and K. Nishihara, December 1975. AD-A023456. It is propossd that the 3-D representation of an object is based primarily on a stick-figure configuration, where each stick represents one or more axes in the object's generalized cylinder representation. The loosely hierarchical description of a stick-figure is interpreted by a special purpose processor, able to maintain two vectors and the gravitational vertical relative to a Cartesian space-frame. It delivers information about the appearance of these vectorß, which helps the system to rotate its model into the correct 3-D orientation relative to the viewer during recognition.

342 The Development of Musical Intelligence j: Strategies for Representing Simple Rhythms, Jeanne Bamberger, November 1975. ($2.10). (LOGO Memo 19). This paper presents a system for understanding the concept of near and far, weighing such factors as purpose of judgement, dimensions of the objects, absolute size of the distance, and size of the distance relative to other objects, ranges, and standards.

348 Turtls Escapes the Plane: Some Advanced Turtle Geometry, Andy diSessa, December 1975. ($1.30). (LOGO Memo 21). Since the LOGO Turtle took his first step he has been mathematically confined to running around on flat surfaces. Fortunately the physically intuitive, procedurally oriented nature of the Turtle which makes him a powerful explorer in the plane is equally, if not more apparent when he is liberated to tread on curved surfaces.

349 An Interpreter for Extended Lambda Calculus, Gerald J. Sussman and Guy L. Steele, Jr., December 1975. ($1.70). (AD-AD2B-595). Inspired by ACTORS (Greif and Hewitt) (Smith and Hewitt), we have implemented an interpreter for a LISP-like language, SCHEME, based on the lambda calculus (Church), but extended for side effects, multiprocessing, and process synchronization.

351 A State Space Model for Sensorimotor Control and Learning, Marc Raibert, January 1976. ($1.30). (AD-A026-96D). This is the first of a two part presentation of a model which deals with problems of motor control, motor learning, adaptation, and sensorimotor integration. In thi3 section the problems are outlined and a solution is given which makes use of a state space

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memory and a piece-wise linearization of the equations of motion. A forthcoming companion article will present the results of tests performed on an implementation of the model.

353 Lambda: The Ultimate Imperative, Guy Lewie Steele, Jr. and Gerald Jay Sussman, March, 1976. (AD-AO3D-751). We demonstrate how to model the following common programming constructs in terms of an applicative order language similar to LISP: Simple recursion; iteration; compound statements and expressions; GO TO and assignment; continuation-passing; escape expressions; fluid variables; call by name, call by need, and call by reference. The models require only (possibly self-referent) lambda application, conditionals, and (rarely) assignment. No complex data structures such as stacks are used. The models are transparent, involving only local syntactic transformations.

355 Artificial Intelligence a personal view, David Marr, March 1978. The goal of A.I. is to identify and solve useful— information processing problems. In so doing, two types of theory arise. Here, they are labelled Types I and 2, and their characteristics are outlined. This discussion creates a more than usually rigorous perspective of the subject, from which past work and future prospects are briefly reviewed.

356 Logo Progress Report 1973-1975, H. Abelson, J. Bamberger, I. Goldstein, and S. Papert, September 1975, Revised March 1976.(LOGO Memo «22). ($1.30). Over the past two years, the Logo Project has grown along many dimensions. This document provides an overview in outline form of the main activities and accomplishments of the past as well as the major goals guiding our current research.

357 From Understanding Computation to Understanding Neural Circuitry, D. Marr and T. Poggio, May 1976. ($1.70). (AD-AD26-875). The CNS needs to be understood at four nearly independent level3 of description: (1) that at which the nature of a computation is expressed; (2) that at which the algorithms that implement a computation are characterized; (3) that at which an algorithm is committed to particular mechanisms; and (4) that at which the mechanisms are realized in hardware. In general, the nature of a computation is determined by the problem to be solved, the mechanisms that are used depend upon the available hardware, and the particular algorithms chosen depend on the problem and on the available mechanisms. Examples are given of theories at each level.

358 The Text-Justifier TJ6, Joseph D. Cohen, May 1976. This memo, intended as both a reference and user's manual describes the text-justifying program TJ6, which compiles a neat output document from a sloppy input manuscript

359 Spatial Knowledge, Benjamin Kuipers, June 1978. (AD-AO2B-874). This paper introduces a model of spatial cognition to describe the states of partial knowledge that people have about the spatial structure of a large-scale environment. Spatial knowledge has several different representations, each of which captures one aspect of the geography. With knowledge stored in multiple representations, we must examine the procedures for assimilating new information, for solvingproblems, and for communicating information between representations.

360 Using Computer Technology to Provide a Creative Learning Environment for Preschool Children, Radia Perlman, May 1976. TORTIS is a system of special terminals together with software wNch is designed to provide programming capability and be accesible for use by very young children.

363 Occlusion Club3and Subjective Contours, Kent A. Stevens, July 1978. The paper describes some experiments with a visual agnosia patient who has lost the ability to perceive subjectivecontours. Thepatient's interpretationsof simple examples of occlusion indicate that he fails to notice monocular occlusion clues, as well. The findings support the hypothesis that subjective contours are constructions that account for occluded figures., in the absence of objective edges. The patient's ability to perceive contours by stereopsis demonstrates that

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stereopsis independently gives rise to disparity contours. Furthermore, the overall results strongly suggest that the detection of occlusion is modularized, and that the module for detecting monocular occlusion clues is not the same as that which provides occlusion clues on the basis of stereopsis.

364 Cooperative Computation of Stereo Disparity, D. Marr and T. Poggio, June 1978. ($1.30). (AD- AO3O-748). (In Science, 194, 282-287, 15 October, 1976). The extraction of stereo disparity information from two images depends upon establishing a correspondence between them. This article analyzes the nature of the correspondence computation, and derives a cooperative algorithm that implements it. We show that this algorithm successfully extracts information from random-dot stereograms, and its implications for the psychophysics and neurophysiology of the visual system are briefly discussed. 366 Proposal to the Advanced Research Projects Agency, P. H. Winston and staff of the MIT Al Lab, May 1976. ($3.20) (AD-AD2B-709). This is the substance of a proposal submitted in June, 1975, for research in the areas of large data bases and intelligent terminals, applications of machine vision and manipulation, basic studies in Artificial Intelligence, and LISP machine development.

367 Filling-in The Gaps: The Shape of Subjective Contours and a Model for Their Generation, Shimon Ullman, October 1976. (AD-A034-091). The properties of isotropy, smoothness, minimum curvature and locality suggest the shape of filled-in contours between two boundary edges. The contours are composed of the arcs of two circles tangent to the given edges, meeting smoothly, and miminizing the total curvature. It is shown that shapes meeting all the above requirement can be generated by a network which performs simple, local computations. It is suggested that the filling-in process plays an important role in the early processing of visual information.

368 A System for Understanding Mathematical FORTRAN Programs, Richard C. Waters, August 1976. ($2.10). This paper proposes a system which, when implemented, will be able to understand mathematical FORTRAN programs such as those in the IBM Scientific Subroutine Package.

369 Physiology and Psychology of Color Vision A Review, David Taenzer, August 1976. ($1.70). This paper is a review of the anatomy, physiology,— and psychology of human color vision.

370 Synthesizing Constraint Expressions, Eugene C. Freuder, July 1978. ($1.30). (AD-A034-011). An algorithm is presented for determining the values which simultaneously satisfy a set of relations, or constraints, involving different subsets of n variables. Therelations are represented in a serie3 of constraint networks, which ultimately contain a node for every subset of the n variables. Constraints may bs propagated through such networks in (potentially)parallel fashion to determine the values which simultaneously satisfy all the constraints. The iterated constraint propagation serves to mitigate combinatorial explosion. Applications in scene analysis, graph theory, and backtrack search are provided.

371 NSF Proposal: An Evaluative Study of Modern Technology in Education, Seymour A. Papert, June 1976. ($1.70). This proposal to the NSF describes a new phase of research planned in LOGO. Previous phases have concentrated on developing a conceptual superstructure (theories and teaching methods] and a material infra-structure (hardware and software) for a new style of using computers in education. We now want to test, to prove and to disseminate the results of our work, which will, of course, continue along the lines of the early phases.

372 Analysis of Occluding Contour, David C. Marr, October 1976. ($2.10). (AD-A34-010). Almost nothing can be deduced about a general 3-D surface given only its occluding contours in an image, yet contour information is easily and effectively used by us to infer the shape of a surface. Therefore, implicit in the perceptual analysis of occluding contour must lis various assumptions about the viewed surfaces. The assumptions that seem most natural are (a) that the distinction between convex and concave segmente reflecte real properties of the viewed surface; and (b) that contiguous portions of contour arise from contiguous parts of the viewed surface — i.e.,

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there are no invisible obscuring edges. It is that the viewed surface is a generalized cone. Methods are defined for finding the axis of such a cone, and for segmenting a surface constructed of several cones into its components, whose axes can then be found separately. These methods, together with the algorithms for implementing them devised by Vatan and Marr (1977), provide one link between an uninterpreted figure extracted from an image, and the 3-D representationtheory of Marr and Nishihara (1977). 373 Some Poetic and Social Criteria for Education Design, Seymour A. Papert, June 1976. A ten- year forecast for computers and communications implications for education.

374 A Computerized Look at Cat Locomotion or One Way to Scan a Cat, Glen Speckert, July 1976. ($2.10). (AD-AO3l-856). This paper describes a three phase project concerning the watching, analyzing, and describing of motions of a cat in various gaits. All data is based on two 16mm films of an actual cat moving on a treadmill.

375 A Cass Study of a Young Child Doing Turtle Graphics in LOGO, Cynthia J. Solomon and Seymour Papert, July 1976 (LOGO Memo 28). ($0.90). This study was performed from January to April 1975 and explores some important issues with regard to using computers in education. It probes into the question of what programming ideas and projects will engage young children. In particular, a seven year old child's involvement in turtle graphics is presented as a case study.

376 Computational Geometry of Linear Threshold Functions, Harold Abelson, July 1976. ($1.70). Linear threshold machines are defined to be those whose computations are based on the outputs of a set of linear threshold decision elements. The number of such elements is called the rank of the machine. An analysis of the computational geometry of finite-rank linear threshold machines, analogous to the analysis of finite-order perceptrons given by Minsky and Papert, reveals that the use of such machines as "general purpose pattern recognition systems" is severely limited. For example, these machines cannot recognize non-trivial figures "in context".

377 Representationand Recognition of the Spatial Organization of Three Dimensional shapes, 0. Marr and H. K. Nishihara, August 1978. ($2.10). (AD-AO3l-882). A method is given for representing 3- D shapes. It is based on a hierarchy of stick figures (called 3-0 models), where each stick corresponds to an axis in the shape's generalizedcone representation.

378 Arithmetic Shifting Considered Harmful, Guy L. Steele, Jr., September 1978. ($0.90). (AD-AO3l- -883]. For more than a decade there has been great confusion over the semantics of the standard "arithmetic right shift" instruction. This paper quotes a large number of sources to prove the widespread extent of this confusion, and then proceeds to a short discussion of the problem itself and what to do about it.

379 LAMBDA: The Ultimate Declarative, Guy Lewis Steele, Jr., November 1976. ($1.70). (AO-A034- -090]. In this paper, a sequel to LAMBDA: The Ultimate Imperative, a new view of LAMBDA as a renaming operator is presented and contrasted with the usual functional view taken by LISP.

380 Forward Reasoningand Dependency-Directed Backtracking in a System for Computer-Aided Circuit Analysis, Richard M. Stallman and Gerald Jay Sussman, September 1976. (AD-A035-719). We present a rule-based system for computer-aided circuit analysis. The set of rules, called EL, is written in a rule language called ARS. Rules are implemented by ARS as pattern-directed invocation demons monitoring an associative data base. Deductions are performed in an antecedent manner, giving EL's analysis a catch-as-catch-can flavor suggestive of the behavior of expert circuit analyzers.

381 Wumpus Advisor 1: A First Implementation Of A Program That Tutors Logical and Probabilistic Reasoning Skills, James L. Stansfield, Brian P. Carr, and Ira P. Goldstein, October 1976. ($2.10). (AD-AD36-678). The Wumpus Advisor program offers advice to a player involved in choosing the best move in a game for wNch competence in dealing with incomplete and uncertain knowledge is

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required. The design and implementation of the advisor explores a new paradigm in Computer Assisted Instruction, in which ths performance of computer-based tutors is greatly improved through the application of Artificial Intelligence techniques.

382 Dual Coding and the Representation of Letter Strings, Steven T. Rosenberg, July 1977. ($0.90). Sub-strings derived from four-letter etrings (eg. ABCD) were presented to subjects using a variation on Bransford and Franks' (1971) paradigm. Each string was in either upper or lower case. Subjects were then tested for recognition of the strings, false recognition of translations of the strings into the other case, and false recognitions of new but legal strings. Subjects accepted previously seen strings most frequently, followed by translations, with New strings accepted least often. This replicates Rosenberg and Simon's (in press) findings with sentences and pictures that express ths same concept. However, in the present experiment the two forms of a string wre unbiased with respect to a verbal or pictorial encoding. The forms in which a string could appear (upper or lower case) were not confounded with the two types of encoding (verbal and pictorial) hypothesized by a dual coding theory. The results supported the view that the previously reported difference between the original form and a translation is best Explained by a model which uses a single representation that preserves some form distinctions.

383A Overview of a Linguistic Theory of Design, Mark L. Miller and Ira P. Goldstein, February 1977 (LOGO Memo 30A). (AD-AD3B-977). ($1.30) SPADE is a theory of the design of computer programs in tsrms of complementary planning and debugging processes. An overview of the authors' recent research on this theory is provided. SPADE borrows tools from computational linguistics grammars, augmented transition networks (ATN's), chart-based parsers — to formalize planning— and debugging. The theory has been applied to parsing protocols of programming episodes, constructing a grammar-based editor in which programs are written in a structured fashion, and designing an automatic programming system based on the ATN formalism.

384 M Based Personal Learning Environments: Directions for Long Term Research, Ira P. Goldstein and Mark L. Miller, December 1976. The application of artificial intelligence(Al) techniques to the design of personal learning environments is an enterprise of both theoretical and practical interest. In the short term, the procees of developing and testing intelligent tutoring programs serves as a new experimental vehicle for exploring alternative cognitive and pedagogical theories. In the long term, such programs should supplement the educational supervision and guidance provided by human teachers. This paper illustrates our long-term perspective by a scenario with a hypothetical tutoring system for elementary graphics programming.

385 Parsing Protocols Using Problem Solving Grammars, Mark L. Miller and Ira P. Goldstein, December 1976. ($1.70). The theory of the planning and debugging of programs is formalized as a context free grammar. The grammar is used to reveal the constituent structure of problem solving episodes, by parsing protocols in which programs are written, tested, and debugged. This is illustratsd by he detailed analysis of an actual session with a beginning student. The virtues and limitations of ths context free formalism are considered.

386 SPADE: A Grammar Based Editor For Planning And Debugging Programs, Mark L. Miller and Ira P. Goldstein, December 1976. ($2.10). (AD-A036-783). A grammar of plans is developed from a taxonomy of basic planning techniques. This grammar serves as the basis for the design of a new kind of interactive programming environment (SPADE), in which programs are generated by explicitly articulating planning decisions. The utility of this approach to program definition is that a record of these decisions, called the plan derivation, provides guidance for subsequent modification or debugging of the program. The enterprise embodies Dijkstra's philosophy of programming in a structured fashion, but represents a more detailed study of planning and debugging techniques than has previously been attempted.

387 Structured Planning and Debugging A Linguistic Theory of Design, Ira P. Goldstein and Mark L. Miller, December 1976. ($2.10). (AD-A036-BI5). A unified theory of planning and debugging ie explored by designing a problem solving program called PATN. PATN uses an augmented transition

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network (ATN) to represent a broad range of planning techniques, including identification, decomposition, and reformulation. PATN's plans may manifest "rational bugs", which result from heuristically justifiablebut incorrect arc transitions in the planning ATN. This aspect of ths theory is developedby designing a complementary debugging module called DAPR, which would diagnose and repair the errors in PATN's annotated plans. PATN has not yet been implemented, but sufficient detail is presented to provide a theoretical framework for reconceptualizing Sussman's [1973] HACKER research. The theory is called "Structured Planning and Debugging" to emphasize its potentialrole in this enterprise.

388 PAZATN: A Linguistic Approach To Automatic Analysis of Elementary Programming Protocols, Mark L. Miller and Ira P. Goldstein, December 1976. ($2.60). PATN is a design for a machine problem solver wNch uses an augmented transition network (ATN) to represent planning knowledge. In order to explore PATN's potential as a theory of human problem solving, a novel approach to protocol analysis is presented. Pursuing an analogy to computational linguistics, an interpretation of a protocol is taken to be a parse tree supplemented by semantic and pragmatic annotation attached to various nodes. This paradigm has implications for constructing a cognitive model of the individual and designingcomputerized tutors.

389 A Preliminary Proposal for Research on The Computer as Coach: An Athletic Paradigm for Intellectual Education, Ira Goldstein, January 1977 Over the next five years, computer games will find their way into a vast number of American homes, creating a unique educational opportunity: the developmentof "computer coaches" for the serious intellectual skills required by some of these games. From the player's perspective, the coach will provide advice regarding strategy and tactics for better play. But, from the perspective of the coach, the request for help is an opportunity to tutor basic mathematical, ecientific, or other kinds of knowledge that ths game exercises. Establishing an "athletic" paradigm for skills usually consider the antithesis of ordinary sports is an exciting prospect. There are, however, critical research issues which must be addressed. While the hardware needed for games and coaches will continue to drop in cost, the software technology (and related educational and psychological theory) for designing competent coaches does not yet exist. This is a proposal to develop the theory and design for such coaches, to implement prototypes, and to Experiment with their ability to convey important intellectual skills.

391 Grammar as a Programming Language, Neil Rowe, October 1976. ($1.30). This paper discusses some student projects involving generative grammars.

392 Control of Locally Parallel Structure, Kent A. Stevens, March 1977. ($1.30). A Moire-like effect can be observed in dot patterns consisting of two superimposed copies of a random dot pattern where one copy has been expanded, translated, or rotated. One perceives in these patterns a structure that is locally parallel. Our ability to perceive this structure is shown by experiment to be limited by the local geometry of the pattern, independent of the overall structure or the dot density. A simple representation of locally parallel structure is proposed, and it is found to be computable by a non-iterative, parallel algorithm. An implementation of this algorithm is demonstrated. Its performance parallels that observed experimentally, providing a potential explanation for human performance. Advantages are discussed for ths early description of locally parallel structure in the course of visual processing.

393 NSF Proposal: Student Science Training Program In Mathematics, Physics And Computer Science, Harold Abelson and Andy diSessa, September 1976. ($1.70) This report describes, in soma dstail, the styls of the program, thecurriculum and the projects the students undertook.

394 Local Methods for Localizing Faults in Electronic Circuits, Johan de Kleer, November 1976. (Formerly Working Paper 109). ($1.30). (AD-A036-007). The work described in this paper is part of an investigation of the issues involved in making expert problem solving programs for engineering design and for maintenance of engineered systems. In particular, the paper focuses on the troubleshooting of electronic circuits.

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395 Pro-Readers' Concepts of the English Word, Robert Lawler, November 1976. ($3.10). Pre-readers exhibit concepte of the English word different from those of literate adults. A concept development theory is offered to interpret this data and their relation to learning to read.

398 Capturing Intuitive Knowledge in Procedural Description, Jeanne Bamberger, December 1976. ($0.90). Intuitive knowledge is not a static structure, but rather a continuing process of constructing coherence and meaning out of the sensory phenomena that come at you.

399 Symbolic Evaluation Using Conceptual Representations for Programs with Side-Effects, Akinori Yonezawa and Carl Hewitt, December 1976. ($1.70). (AD-AO3B-244). Symbolic evalutation is a process which abstractly evaluates a program on abstract data. A formalism based on conceptual representations is proposed as a specification language for programs with side-effects. Relations between algebraic specifications and specifications based on conceptual representations are discussed and limitations of the current algebraic specification techniques are pointed out.

400 The Competence/Performance Dichotomy in Programming, Vaughn R. Pratt, January 1977. ($0.90). (AD-AO3B-245). We consider the problem of automating some of the duties of programmers. We take as our point of departure the claim that data management has been automated to the point where the programmer concerned only about the correctness (as opposed to the efficiency) of his program need not involve hmself in any aspect of the storage allocation problem. We focus on what we feel is a sensible next step, the problem of automating aspects of control.

401 Development of Musical Intelligence Ih Children's Representation of Pitch Relations, Jeanne Bamberger, December 1976. ($1.30). The work reported here is an outgrowth of studies in the development of musical intelligenceand learning that havebeen underway for about four years.

405 NUDGE, A Knowledge-based Scheduling Program, Ira P. Goldstein and R. Bruce Roberts, February 1977. ($1.30). Traditional scheduling algorithms (using the techniques of PERT charts, decision analysis or operations research) require well-defined, quantitative, complete sets of constraints. They are insufficient for scheduling situations where the problem description is ill-defined, involving incomplete, possibly inconsistent and generally qualitative constraints. The NUOGE program uses a extensive knowledge base to debug scheduling requests by supplying typical values for qualitative constraints, supplying missing details and resolving minor inconsistencies. The result is that an informal request is converted to a complete description suitable for a traditional scheduler.

406 Overlays: A Theory for Computer Aided Instruction, Brian Carr and Ira P. Goldstein, February 1977. ($1.30) Overlay modelling is a technique for describing a student's problem solving skills in terms of a modular program designed to be an expert for the given domain. The model is an overlay on the expert program in that it consists of a set of hypotheses regarding the student's familiarity with the skills employed by the expert.

407 Annotated Production Systems: A Model for Skill Acquisition, Ira P. Goldstein and Eric Grimson, February 1977. ($1.30). (LOGO Memo 44). Annotated Production Systems provide a procedural model for skill acquisition by augmenting a production model of the skill with formal commentary describing plans, bugs, and interrelationships between various productions. This commentary supports processes of efficient interpretation, self-debugging and self-improvement. The theory of annotated productions is developed by analyzing the skill of attitude instrument flying. An annotated production interpreter has been written that executes skill models which control a flight simulator. Preliminary evidence indicates that annotated productions effectively model certain bugs and certain learningbehaviors characteristic of student pilots.

408 The FRL Primer, R. Bruce Roberts and Ira P. Goldstein, July 1977. ($1.30). The Frame Repressntation Language (FRL) is an experimental language written to explore the use of frames as a knowledge representation technique. The term "frame" as used in FRL was inspired by PAGE 16

Minsky's (75) development of frame theory. FRL extends the traditional Property List representation scheme by allowing properties to have comments, defaults and constraints, to inherit information from abstract forms of the same type, and to have attached procedures triggered by adding or deleting values, or if a value is needed. We introduce FRL with the aid of a simple example: WHOSIS, a database of Al persons' names, addresses, interests, and publications. A second section contains an abridged manual describing FRL's most-used commands and conventions.

409 Ths FRL Manual, R. Bruce Roberts and Ira P. Goldstein, June 1977. ($0.90).

410 ViewingControl Structures as Patterns of Passing Messages, Carl Hewitt, December 1976. (AO-AO3B-246). The purpose of this paper is to discuss some organizational aspects of programs using the actor model of computation. In this paper we present an approach to modelling intelligence in terms of a society of communicating knowledge-based problem-solving experts. In turn each of the experts can be viewed as a society that can be further decomposed in the same way until the primitive actors of the system are reached. We are investigating the nature of the communication mechanisms needed for effective problem-solving by a society of experts and ths conventions of discourse that make this possible. In this way we hope eventually to develop a framework adequate for the discussion of the central issues of problem-solving involving parallel versus serial processing andcentralization versus decentralization of control and information storage.

412 Control and Learning by the State Space Model: Experimental Findings, Marc Raibert, April 1977. ($1.70). This is the second of a two-part presentation of a model for motor control and learning. The model was implemented using a small computer and the MIT-Scheinman manipulator. Experiments were conducted which demonstrate the controller's ability to learn new movements, adapt to mechanical changes caused by inertia! and elastic loading, and generalize its behavior among similar movements. A second generation model, based on improvements suggested by these experiments, is suggested.

413 Level of Complexity in Discourse for Reference Disambiguation and Speech Act Interpretation, Candace Bullwinkle, Mey 1977. ($1.30). This paper presents a discussion of means of describing the discourse and its components which makes speech act interpretation and reference disambiguation possible with minimal search of the knowledge in the database. A portion of this paper will consider how a frames representation of sentences and common sense knowledge provides a mechanism for representing the postulated discourse components. Finally some discussion of the use of the discourse model and of frames in a discourse understanding program for a personal assistant will be presented.

414 Learning by Hypothesizing and Justifying Transfer Frames, Patrick H. Winston, April 1977. ($1.30). Learning is defined to be the computation done by a student when there is a transfer of information to him from a teacher. In the particular kind of learning discussed, the teacher names a source and a destination. In the sentence, "Robbie is like a fox," fox is the source and Robbie is the destination. The student, on analyzing the teacher's instruction, computes a kind of filter called a transfer frame. It stands between the source and the destination and determines what information is allowed to pass from one to the other.

Computing the transfer frame requires two steps: hypothesis and evaluation. In the hypothesis step, potentially useful transfer frames are produced through an analysis of the information in the source and its immediate relatives. For Robbie, a robot, the way it compares with other robots would be noted. In the evaluation step, the better of the hypothesized frames are selectd through a study of the destination frame, its relatives, and the general context. Some source-destination pairs may be generated by the student acting alone. There is also the possibility of making notes that are useful in deciding if conclusion makes sense.

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415 Representing Visual Knowledge, 0. Marr, May 1977. ($2.60). Vision is the construction of efficient symbolic descriptions from images of the world. An important aspect of vision is the choice of representations for the different kind of information in a visual scene. In the early stages of the analysis of an image, the representations used depend more on what it is passible to compute from an imags than on what is ultimately desirable, but later representations can be more sensitive to the specific needs of recognition. This essay surveys recent work in vision at M.I.T. from a perspective in which the representational problems assume a primary importance. An overall framework is suggested for visual information processing, in which the analysis proceeds through three representations; (1) ths primal sketch, which makes explicit the intensity changes and local two-dimensional geometry of an image, (2) the 2 1/2-D sketch, which is a viewer-centered representation of the depth, orientation and discontinuities of the visible surfaces, and (3) the 3-D model representation, which allows an object-centered description of the three-dimensional structure and organization of a viewed chape. Recent results concerning processes for constructing and maintaining these repreeentationa are summarized and discussed.

416 Representation and Recognition of the Spatial Organization of Three Dimensional Shapes, D. Marr and H. K. Nishihara, May 1977. ($1.70). The human visual process can be studied by examining the computational probleme associated with deriving useful information from retinal images. In this paper, we apply thie approach to the problem of representing three-dimensional shapes for the purposs of recognition. 1. Three criteria, accessibility, scope & uniqueness, and stability £ sensitivity, are presented for judging the usefulness of a representation for shape recognition. 2. Three aspects of a representation's design are considered, (i) the represention's coordinated system, (ii) its primitives, which are the primary units of shape information used in the representation, and (iii) the organization the representation imposes on the information in its descriptions. 3. In terms of these design issues and the criteria presented, a shape representation for recognition should: (i) use an object-centered coordinate system, (ii) include volumetric primitives of varied sizes, and (iii) have a modular organization. A representation based on a shape's natural axes [for example the axes identified by a stick figure) follows directly from these choices. 4. The basic process for deriving a shape description in this representation must involvs: (i) a means for identifying the natural axes of a shape in its image and (ii) a mechanism for transformingviewer-centered axis specifications in an object-centered coordinate system.

417 Wusor M: A Computer Aided Instruction Program with Student Modelling Capabilities, Brian Carr, May 1977. ($2.60). (LOGO Memo 45). Wusor II is the second program that has been developed to tutor studente in the game of Wumpus. The result is a system which, according to prelimiary results, is highly effective at tutoring students of varied abilities.

422 Light Source Effects, K. Forbus, May 1977. ($1.70). The perception of surface luster in achromatic single view images seeme to depend on the existence of regions with source-like properties. Thess regions are due to the interaction of the specular component of the surface's reflectance and the illumination. Light source effecte are broken down into three catagories according to gross aspects of the physical situation in which they occur, and criteria for detecting the regions they cause are suggested.

423 COMEX: A Support System for a Commodities Analyst, J. Stansfield, July 1977). ($1.30). The intelligent support system project is developing a program (COMEX) to assist a commodities expert in tasks such as interpreting data, predicting trends and intelligent noticing. Large amounts of qualitative and quantitative information about factors such as weather, trade and crop condition need to be managed. This memo presents COMEX-0, a prototype system written in FRL, a frame- based language (Goldstein and Roberts 1977). COMEX-0 has a complaint handling system, frame- structure matching and simple reasoning. By conversing with a user, it builds groupings of frame structures to represent events. These are called CLUSTERS and are proposed as a new representation method. New CLUSTERS are built from previously defined ones using INSTANTIATION and AGGREGATION, two methods which combine with frame inheritance and constraints to maks up a general even representation mechanism. Clusters capture the idea of generic patterns of relationships between frames and raise an issue named the GENERIC PAGE 18

CONSTRAINT PROBLEM concerning constraints between the parts of a cluster. The final section presents plans for future work on qualitative reasoning within COMEX and includes a hypothetical scenario.

425 Electrical Design a Problem for Artificial Intelligence Research, Gerald Jay Sussman, June 1977. ($0,90). This report outlines the problem of intelligent failure recovery in a problem-solver for electrical design. We want our problem-solver to learn as much as it can from its mistakes. Thus we cast the engineering design process on terms of Problem Solving by Debugging Almost-Right Plans, a paradigm for automatic problem-solving based on the belief that creation and removal of "bugs" is an unavoidable part of the process of solving a complex problem. The process of localization and removal of bugs called for by the PSBDARP theory requires an approach to engineering analysis in which every result has a justification which describes the exact set of assumptions it depends upon. We have developed a program based on Analysis of Constraints which can explainthe basis of its deductions. In addition to being useful to a PSBDARP designer, these justificationsare used in Dependency-DirectedBacktracking to limit the combinatorial search in the analysisroutines.

427 Explicit Control of Reasoning, Johan de Kleer, Jon Doyle, Guy L. Steele, Jr., and Gerald Jay Sussman, June 1977. ($1.30). The construction of expert problem-solving systems requires the development of techniques for using modular representations of kowledge without encountering combinatorial explosions in the solution effort. This report describes an approach to dealing with this problem based on making some knowledge which is usually implicitly part of an expert problem solver explicit, thus allowing this knowledge about control to be manipulated and reasoned about. The basic components of this approach involve using explicit representations of the control structure of the problem solver, and linking thie and otherknowledge manipulated by the expert by means of explicit data dependencies.

428 Modelling Distributed Systems, Akinori Yonezawa and Carl Hewitt, June 1977. Distributed systems are multi-processor information processing systems which do not rely on the central shared memory for communication. This paper presents ideas and techniques in modelling distributed systems and its application to Artificial Intelligence. In section 2 and 3, we discuss a model of distributed systems and its specification and verification techniques. We introduce a simple example of air line reservation systems in Section 4 and illustrate our specification and verification techniques for this example in the subsequent sections. Then we disucuss further work.

430 Plain Talk About Neurodevelopmental Epistemology, Marvin Minsky, June 1977. ($1.30). This paper is based on a theory being developed in collaboration with Seymour Papert in which we view the mind as an organized society of intercommunicating "agents". Each such agent is, by itself, very simple. The subject of this paper is how that simplicity affects communication between different parts of a single mind and, indirectly, how it may affect inter-personal communications. 431 Frames-based Text Processing, S. Rosenberg, August 1977. ($1.30). This paper presents an overview of a theory of discourse structure, and discusses a model for assimilating text into a frames based data structure. Ths model ie being implemented in a Frame Representation Language (Goldstein and Roberts 1977). The theory assumes sentences contain links to the database which are relatively easy to compute. These links point to prior themes which contain expectations and procedural knowledge. This knowledge is used to assimilate new sentences to thess themes. At any given time, only procedural knowledge from the indicated theme is active in processing new sentences.

437 Using Synthetic Images to Register Real Images with Surface Models, Berthold K. P. Horn and Brett L. Bachman, August 1977. ($1.70).

A number of image analysis tasks can benefit from registration of the image with a model of the surface being imaged. Automatic navigation using visible light or radar images requires exact

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alignment of such images with digital terrain modele. In addition, automatic classification of terrain, using satellite imagery,requires such alignment to deal correctly with the effects of varying sun engle and surface slope. Even inspection techniques for certain industrial parts may bs improved by this mesne.

We achieve the required alignment by matching the real image with the synthetic image obtained from a surface model and known positions of the light sources. The synthetic imago intensity is calculated using the reflectance map, a convenient way of describing surface reflection as a function of surface gradient. We illustrate the technique using LANOSAT images and digital terrain modele.

Recognition Aug. [MAC-TR- _f + ArAI-TR "230 (Thesis) Griffith, Arnold X., Computer of Prismatic Solids. 1970. -73) AO-711-763. SPECIAL SALE!!!!) An investigation is made into the problem of constructing a model of the appearance to an optical input device of scenes consisting of plane- faced geometric solids. The goal is to study algorithms which find the real straight edges in the scene, taking into account smooth variations in intensity over faces of the solids, blurring of edges, and noise. Objects, *■"¥■ ArAI-TR ■234 (Thesis) Krakauer, Lawrence J., Computer Analysis of Visual Properties of Curved May 1971. (MAC-TR-B3) AD-723-847. ($1.50 SPECIAL SALE!!!!) A method is presented for the visual analysis of objects by computer.lt is particularly well suited for opaque objects with smoothly curved surfaces. The method extracts information about the object's surface properties, including measures of its specularity, texture, and regularity. It also aids in determining the object's shape. September Jf *AI-TR "242 (Thesis) Smoliar, Stephen W., A Parallel Processing Model of Musical Structures, 1971. (MAC-TR-91) AO-731-690. SPECIAL SALE!!!!) EUTERPE is a real-time computer * concepts system for the modeling of musical structures. It provides a formalism wherein familiar of musical analysis may bs readily expressed.

System May 1973. AD- if if *AI-TR "283 (Thesis) Fahlman, Scott E.r A Planninn For Robot Construction Tasks. -773-471. ($1.50 SPECIAL SALE!!!!) This paper describes BUILD, a computer program which generates plans for building specified structures out of simple objects such as toy blocks. A powerful heuristic control structure enables BUILD to use a number of sophisticated construction techniques in its plans. Among the final design, pre-assembly of movable sub-structures on the table, and the use of extra blocks as temporary supports and counterweights in the course of the construction.

_f jf -y-AI-TR-291 (Thesis) McDermott, Drew V., Assimilation of New Information by a Natural LanquaqBT Understanding System. February 1974. AD-780-194. SPECIAL SALE!!!!). This work describes a program, called TOPLE, which uses a procedural model of the world to understand simple declarative sentences. It accepts sentences in a modified predicate calculus symbolism, and uses plausible reasoning to visualize scenes, resolve ambiguous pronoun and noun phrase references, explain in events, and make conditional predications. Because it does plausible deduction, with tentativeconclusions, it must contain a formalism for describing its reasons for its conclusions and what the alternativee ere.

AI-TR ■294 (Thesis) Goldstein, Ira P., Understanding Simple Picture Programs, April 1974. (AD-AOO5- 9D7). ($3.50). What are the characterietice of the process by which an intent is transformed into a plan and then a program? How is a program debugged? A system has been designed to investigate these questions in the context of understanding simple turtle programs for drawing pictures. The eystem called MYCROFT generates commentary to describe the effects, plan and

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anomalies of a turtle program when compared to a model of the intended picture. Repair of the program is then based upon a combination of general debugging technique and specific repair knowledge associated with geometric model primitives.

AI-TR-345 (Thesis) Eugene C. Freuder, Computer System for Visual Recognition Using Active Knowledge, June 1976. ($4.25). A system for visual recognition is described, with implications for the general problem of representation of knowledge to assist control. The immediate objective is a computer system that will recognize objects in a visual scene, specifically hammers.

AI-TR-346 (Thesis) John M. Hollerbach, Hierarchical Shape Description of Objects by Selection and Modification of Prototypes, November 1975. (AO-A024-970). An approach towards shape description, based on prototype modification and generalized cylinders, has been developed and applied to object domains pottery and polyhedra.

AI-TR-347 (Thesis) Robert Carter Moore, Reasoning from Incomplete Knowledge in a Procedural Deduction System, December 1975. ($2.35). (AD-A024-971). This thesis explores methods of increasing the ability of procedural deduction systems to deal with incomplete knowledge. The thesis examines in detail, problems involving negation, implication, disjunction, quantification, and equality. Control structure issues and the problem of modelling change under incomplete knowledge are also considered. Extensive comparisons are also made with systems for mechanical theorem proving.

AI-TR-352 (Thesis) Johan de Kleer, Qualitative and Quantitative Knowledge in Classical Mechanics, December 1975. ($2.35). (AD-AO2l-515). This thesis investigates what knowledge is necessary to solve mechanics problems. A program NEWTON is described which understands and solves problems in a mechanics mini-world of objects moving on surfaces.

AI-TR-354 (Thesis] Charles Rich and Howard E. Shrobe, Initial Report on A LISP Programmer's Apprentice, December 1976. ($4.25). (AD-A035-943). This is an initial report on the design and partial implementation of c LISP programer's apprentice, an interactive programming system to be used by an expert programmer in the design, coding, and maintenance of large, complex programs.

AI-TR-362 (Thesis) Allen Brown, QualitativeKnowledge, Causal Reasoning, and the Localization of Failures, December 1976. ($3^35). This report investigates some techniques appropriate to representing the knowledge necessary for understanding a class of electronic machines radio receivers. A computational performance model WATSON is presented. WATSDN's task— is to isolate failures in radio receivers whose principles of operation have been appropriately described in his knowledge base. The thesis of the report is that hierarchically organized representational structures are essential to the understanding of complex mechanisms. Such structures lead not only to descriptions of machine operation at many levels of detail, but also offer a powerful means of organizing "specialist" knowledgefor therepair of machines when they are broken.

AI-TR-397 (Thesis) Torres Lozano-Perez, The Design of a Mechanical Assembly System, December 1976. ($3.25). (AD-A036-734). This report describes a mechanical assembly system called LAMA (Language for Automatic Mechanical Assembly). The goal of the work is to create a system that transforms a high-level description of an automatic mechanical assembly operation into a program for execution by a computer controlled manipulator. The assembly problem is seen as ths problem of achieving a set of geometrical constraints between basic objects while avoiding unwanted collisions.

AI-TR-402 (Thesis) Drew Vincent McDermott, Flexibilityand Efficiency jn a Computer Program for Designing Circuits, December 1976. ($4.35). This report is concerned with the problem of achieving flexibility(additivity, modularity) and efficiency (performance, expertise] simultaneously in one Al program. It deals with ths domain of elementary electronic design. Ths proposed solution is to provide a deduction-driven problem solver with built-in control-structure concepts. This problem solver and its knowledge bass in ths application areas of design and electronics are

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described. The program embodying it is being used to explore the solution of some modest problems in circuit design. Conclusions regarding representation and use of knowledge are drawn.

AI-TR-403 (Thesis) Richard Brown, Use of Analogy to Achieve New Expertise, April 1977. (sjj_.3s). We will take ths view that the end result of problem solving in some world should be increased sxpertness. In ths contsxt of computers, increasing expertness means writing programs. This thesis is about a procsss, reasoning by analogy,that writes programs. AI-TR-418 3 (Thesis) Benjamin J. Kuipers, Representing Knowledge of Large-scale Space, July 1977. ($!p.35). This dissertation presents a model of the knowledge a person has about ths spatial structurs of a large-scale environment: the "cognitive map". The functions of the cognitive map are to assimilate new information about the environment, to represent the current position, and to anser routs-finding and rslative-position probleme. This model (called the TDUR model) analyzes the cognitive map in terme of symbolic dsscriptions of the environment and operations on those descriptions.

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