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Some of the major results of future goals of an automatic program synthesis project are described in the two papers that comprise this document. The first paper gives a detailed algorithm for synthesizing a computer program from a trace of its behavior. Since the algorithm involves a search, the length of time required to do the synthesis of nontrivial programs can be quite large. Techniques are given for preprocessing the trace information to reduce enumeration, for pruning the search using a failure memory technique, and for utilizing multiple traces to the best advantage. The results of numerous tests are given to demonstrate the value of the techniques. The other paper gives a brief overview of the automatic programming system within which the above algorithm is being used. This system is still under development. (Author/CH)

The primary aim of these five technical papers is to indicate aspects of proof theory which may be of use in the study of non-numerical computing. The three main papers are entitled: "Checking of Computer Programs;""Consistency Proofs and Programs for Translators;" and "Experiments with Computers on the Complexity of Non-numerical computations." The author shows that many theorems on computability in traditional metamathematics are of little use to the computer scientist because they do not lead to feasible algorithms. He also suggests alternative approaches to proof theory which would be of greater applicability. (MM)

THE analysis of the protein composition of blood serum or plasma by means of zone electrophoresis on filter paper has stimulated interest in clinical laboratories throughout the world. In addition to numerous publications dealing with the applications of the technique in various pathological conditions, critical assessments of its validity and accuracy have appeared1–4, in which attention is properly directed to the limitations of the method from the point of view of the numerical evaluation of the separated protein fractions. It has seemed desirable to undertake a study of the accuracy and reproducibility of this method of protein analysis, using two of the most commonly employed protein-dyeing techniques.

It has been observed, and proved experimentally, that the nature of the paper surface has a considerable effect on the tone reproduction characteristics of halftone processes. It is concluded that any tone reproduction curve related to a halftone process is meaningless unless the type of paper to which it applies is specified in general terms.

This paper describes the development and application of an algorithm which generates non-linear representations of English text. The algorithm uses the results of a syntactic analysis system and a set of rules which prescribe linkages to generate a graph of a sentence. The shape of these graphs corresponds to the syntax of the sentence; the labels correspond to the vocabulary of the sentence and the edge types correspond to case grammar roles. The sentence graphs can then be interconnected at common nodes and analyzed according to common edges. Preliminary experimentation has yielded promising results. It appears that the algorithm produces a representation of English text which could be quite useful in automatic language processing.

The main arguments that led to the definition of the 1931 CIE colour system and of the Standard Observer are presented, together with an interpretation of the colour co-ordinates obtained in this system. The correlation of CIE co-ordinates with visual estimates is considered, and other systems of more uniform colour space are discussed. A method of expressing colour differences is indicated and related to colour tolerance. The essential principles on which instrumental methods are based are also given, together with brief descriptions of some typical instruments of different types. The principal applications of colorimetry are outlined and some of the advantages and disadvantages of instrumental methods as compared with visual methods are suggested. Simple numerical examples are included to illustrate important points.

THE recent communication on this subject by R. Robinson1 has prompted me to record some observations made about two years ago on this subject.

The report is a collection of Working Papers in Speech Recognition on the following topics: Organization of the HEARSAY II speech understanding system; The DRAGON system -- an overview; Parameter-independent machine segmentation and labeling; A new time-domain analysis of fricatives and stop consonants; Sub-lexical levels in the HEARSAY II speech understanding system; Inference and use of simple predictive grammars; Real-time linear predictive coding of speech on the SPS-41 microprogrammed triple-processor system; A 16-bit A-D-A conversion system for high-fidelity audio research.

This paper as I understand it tries to set up four levels of linguistic representation in accordance with semantic interpretation. I shall go directly to p. 424 where an outline is given as Table I.

As part of a research program aimed at determining the parameters influencing the effectiveness of a message retrieval system, a collection of 10, 000 technical abstracts was indexed and retrieval experiments were conducted with them. Since part of the work involved the development and test operation of an associative retrieval system, basic data about the distribution of words and word strings were gathered in preparing the system for test and trial. These statistics were thought to be of possible interest to other workers in the field and are gathered as a series of loosely connected papers in this volume under the following groupings: Characteristics and Indexing of GE Data Base; Comparison of Manual and Machine Selected Vocabularies; Vocabulary Distribution Studies, and Studies of Content Bearing Units in Text.

In contrast to his views of some years ago Suppes in now convinced that modal concepts are essential to standard scientific talk. Yet he emphasizes two main points: (1) in a majority of cases the modal concepts remain implicit in that talk, and (2) this logic is scarcely used in either theoretical or experimental analysis of empirical phenomena. Furthermore, in dealing with probability and referring in particular to the sample space, he substantially says that modal concepts are left implicit to eliminate excess baggage.

The study of image evaluation is a complex subject requiring the simultaneous consideration of the object, optical system, detector, and mechanism for processing the detector's signals. Image quality for any given photo-optical system depends upon such diverse considerations as granularity, light scattering, numerical aperture, tone reproduction, the degree of correction in the image-forming optics, etc.

In a recent paper 1 I stated that von Neumann had originated the suggestion for the use of Schur's canonical form for arbitrary matrices. I have since learned that the suggestion actually is due in the first instance to John Greenstadt, who brought it to von Neumann's attention. The history of this is rather interesting and was communicated to me in a letter from John Greenstadt, which I quote below. “The full story is, that the triangularization occurred to me early in 1953, after trying in vain to find a general iterative diagonalization procedure, even where one knew that it was possible to diagonalize (defective degeneracy being the impossible case). It seemed to me that one thing that made for the stability of the Jacobi method was the fact that all the elements in the transformation matrix were less than 1. A natural generalization embodying this requirement was to consider unitary transformations. Then, a quick check of Murnaghan's book showed that one could hope only to triangularize, but that this was always possible. “I did some hand calculations on this, and lo and behold! it converged in the few cases I tried. I then programmed it for the CPC and tried many other cases. For several months thereafter, Kogbetliantz, John Sheldon, and I tried to prove convergence, when the algorithm involved the sequential annihilation of off-diagonal elements. We (particularly Sheldon) tried many approaches, but with no hint of success. Finally, in the latter part of 1953, we decided to ask von Neumann, who was then a consultant for IBM, when he was in New York at our offices. “I had prepared a writeup describing the procedure, but von Neumann (rightly) didn't want to bother reading it, so I explained it to him in about two minutes. He spent the next 15 minutes thinking up all the approaches we had thought of in three or four months, plus a few ones—all, however, without promise. “At this point he decided that it was a nontrivial problem, and perhaps not worth it anyway, and immediately suggested minimizing the sum of squares of subdiagonal elements, which is, of course, the truly natural generalization of the Jacobi method. For the next 15 minutes he investigated the case when it would be impossible to make an improvement for a particular pivotal element and found that these cases were of measure zero. “I recoded my procedure for the 701 and tried many other matrices of various sizes. I myself never had a failure, but it has since been demonstrated that the method will indeed fail for a class of matrices. Hence, a proof is clearly impossible. However, I think a statistical proof is possible, along lines suggested by Kogbetliantz, which, however, I have not been able to find. I do not think von Neumann's variation of the method would fail. (However, it is more complicated and time consuming.)”

In the above paper, the authors proposed a modern state-variable type multi-variable regulatory controller involving ''proportional-plus-integral'' (P + I) feedback and ''disturbance feedforward'' terms. This corres-pondence describes some earlier publications, not included in the author's list of ''pertinent literature'', which treated these same topics.

In a 1967 publication, D. P. Gaver studied a probabilistic model of a multiprogramming computer system. His results have been utilized recently by a number of authors. However, we have observed that Gaver's results contain inconsistencies. These inconsistencies are discussed in detail and a correction suggested and verified through an independent derivation.

A method of detecting the phenomenon of latent image reinforcement of a fluorescing screen, and the duration of that phenomenon, is described. The G231 screen so tested was found to be free of this phenomenon.

Nearly 4 years ago in the field of Artificial Intelligence a learning machine called STeLLA was conceived. After three years of computer simulation of the machine in a variety of problem environments, the design is greatly improved, although the main features have survived. Since the machine is being simulated with a vehicle-steering control problem which is second order, non-linear and stochastic it would appear that STeLLA now qualifies for the title of “adaptive controller”.