1IEEE TRANSACTIONS ON COMPUTERS, NOVEMBER 1971

Abstracts of Current Computer Literature

CONTENTS

ABSTRACTS. ....................................................

Al0) GENERAL; STANDARDS; EDUCATION ..................

1) LOGIC AND SWITCHING THEORY; SEQUENTIAL MA-CHINES... ..............................................

2) DIGITAL COMPUTERS AND SYSTEMS.................3) LOGIC DEVICES AND CIRCUITS (HARDWARE).........4) DIGITAL STORAGE AND INPUT-OUTPUT EQUIPMENT..5) PROGRAMMING OF DIGITAL MACHINES.............6) LINGUISTICS, DOCUMENTATION, AND HUMANITIES...7) BEHAVIORAL SCIENCE, PATTERN RECOGNITION, AND

ARTIFICIAL INTELLIGENCE.............................8) MATHEMATICS.........................................9) PROBABILITY, MATHEMATICAL PROGRAMMING, DIG-

ITAL SIMULATION, INFORMATION THEORY, AND COM-MUNICATION SYSTEMS.....................

10) SCIENCE, ENGINEERING, AND MEDICINE..............11) ANALOG AND HYBRID COMPUTERS.................12) REAL-TIME SYSTEMS AND AUTOMATIC CONTROL;

INDUSTRIAL APPLICATIONS............................13) GOVERNMENT, MILITARY, AND TRANSPORTATION

APPLICATIONS .........................................

14) BUSINESS APPLICATIONS OF INFORMATION PRO-CESSING. ...............................................

DESCRIPTOR-IN-CONTEXT INDEX............................IDENTIFIER INDEX.............................................AUTHOR INDEX..............................................

Pages 1421-1429

bstract Numbers9052-9055

9056-90709071-9077

9078-90809081-91069107-9108

9109-91129113-9126

9127-91359136-9137

Pages 1429-1433Page 1434Page 1435

Notice: These abstracts were prepared on a commercial basis by Information Associates under thedirection of Dr. Geoffrey Knight, Jr. The complete material is unavailable from either the IEEE or Infor-mation Associates. If you require copies of any of the papers referred to, we suggest you contact the authorsdirectly. All government research reports (those identified by CFSTI) can be obtained from Clearinghouse,Springfield, Va. 22151.

l4w

ABSTRACTS OF CURRENT COMPUTER LITERATURE

0) GENERAL; STANDARDS;EDUCATION

90521970 Turing Lecture: Some Comments from aNumerical Analyst, J. HI. Wilkinson (Nat.Phys. Lab., Teddington, Middlesex, En-gland); J. Ass. Comput. Mach., vol. 18, pp.137-147, Apr. 1971.A description is given of life with A. M.

Turing at the National Physic4l Laboratoryin the early days of the development of elec-tronic computers (1946-1948). The prssentmood ofpessimism among numerical analystsresulting from difficult relationships withcomputer scientists and mathematicians isdiscussed. It is suggested that in light of pastand present performance this pessimism isunjustified and is the main enemy of progressin numerical mathematics. Some achieve-ments in the fields of matrix computationsand error analysis are discussed and likelychanges in the direction of research innumerical analysis are sketched.

9053Security Techniques for EDP of MultilevelClassffied Information, H. W. Bingham(Burroughs Corp., Paoli); RADC-TR-65-415, 4424-65-112, 194 pp., Dec. 1965; CFSTI,AD 476 557, $3.00.

The study objective was to develop hard-ware and software techniques for security(need-to-know) control of on-line users andprogrammers in multiprogramming multi-processing EDP systems of apparent futuredevelopment. Hardware techniques recom-mended include: 1) processors having twomodes of operation, interrupt entry intocontrol mode in which privileged instructionsare executable, flag bits for identification andcontrol of memory works, 4nd addresschecks against access-differentiated memorybounds; 2) parity checks on intermoduleinformation transfers; 3) input/output con-trol processors which establish and verifyperipheral unit connections, check memoryaddresses against bounds, and confirmsecurity content of record headers beingtransferred; and 4) bulk file control ofphysical record integrity, and lock controlover write permission and flag bit setting topermit supervisor establishment of controlprograms.

9054The Merit of Regional Conmputing Networks,N. R. Nielsen (Stanford U., Calif.); Commun.Ass. Comput. Mach., vol. 14, pp. 319-326,May 1971.

One of the suggested means for stimulat-ing the spread of computing capabilities ininstitutions of higher learning is through theconstruction of regional computing networks.One such network has be-en constructed inthe San Francisco Bay Area by StanfordUniversity. This paper reports upon thelessons learned from the operation of thatnetwork over the past two years. A majorimpact of the network was not so much thecomputer power delivered to the schools asthe awakening of computing awareness andthe fostering of capability development atthese schools. The expertise and assistancefrom the central facility as well as the sharingof ideas among the participants were otherimportant benefits. Both the quality and

variety of services provided by the centralfacility were found to play a key role in theeffectiveness of the network. A regional net-work brings many benefits and should not bejudged as a purveyor of raw computer poweralone.

9055A Mathematical Method for Analyzing theGrowth of a Scientific Discipline, W. Goffman(Case Western Reserve U., Cleveland); J.Ass. Comput. Mach., vol. 18, pp. 173-185,Apr. 1971.

The spread of ideas within a scientificcommunity and the spread of infectiousdisease are both special cases of a generalcommunication process. Thus a generaltheory of epidemics can explain the growthof symbolic logic from 1847 to 1962. Anepidemic model predicts the rise and fall ofparticular research areas within symboliclogic. A Markov chain model of individualmovement between research areas indicatesthat once an individual leaves an area he isnot expected to return.

1) LOGIC AND SWITCHING THEORY;SEQUENTIAL MACHINES

Relational Data File and the Decision Problemfor Classes of Proper Formulas-see 9107.

9056On Effective Procedures for Speeding UpAlgorithms, M. Blum (U. Calif., Berkeley);J. Ass. Comput. Mach., vol. 18, pp. 290-305,Apr. 1971.

This paper is concerned with the nature ofspeedups. Letf be any recursive function. Itis shown that there is no effective procedurefor going from an algorithm forf to anotheralgorithm for f that is significantly faster onall but a finite number of inputs. On theother hand, for a large class of functions f,one can go effectively from any algorithm forf to one that is faster on at least infinitelymany integers. Finally, if one has an algo-rithm for a given function f, and if there isan algorithm which is faster on all but afinite number of inputs, then even though onecannot get this faster algorithm effectively,one can still obtain a pseudo-speedup: Thisis a very fast algorithm which computes avariant of the function, one which differsfrorn the original function on a finite numberof inputs.

9057Another Recursion Induction Principle, J. H.Morris, Jr., (U. Calif., Berkeley); Commun.Ass. Comput. Mach., vol. 14, pp. 351-354,May 1971.

An inductive method for proving thingsabout recursively defined functions is de-scribed. It is shown to be useful for provingpartial functions equivalent and thus appli-cable in proofs about interpreters for pro-gramming languages.

9058Heuristic Minimization ofAND-EXCLUSIVEOR Realization of Switching Functions, V. V.Rao and A. W. Nordstrom (Iowa U., IowaCity); Rep. THEMIS-UI-TR-36, 15 pp.,Feb. 1971; CFSTI AD, 719 394, $3.00.

Based on certain heuristics, a computeralgorithm has been developed to minimize

the AND-EXCLUSIVE-OR realization of a givenswitching function using both complementedand uncomplemented literals. Though noproof could be arrived at about the optimalityor suboptimality of the procedure, com-puter results for the four variable case havebeen very encouraging, suggesting that similarprocedures might lead to an optimum solu-tion of this long standing problem.

9059Realization of Nonlinearly Separable Switch-ing Functions, M. Ali and R. Ahmed (Ali-garh Muslim U., Aligarh, India); IEEETrans. Comput, (Short Notes), vol. C-20,pp. 695-697, June 1971.

In this paper CEP functions are appliedto realize nonlinearly separable switchingfunctions. It is proved that the introductionof these functions may realize all the 22nswitching functions of n binary variables. Amodel of a nonlinear threshold componentis proposed to realize the switching functions.

9060PCN Equivalence Class Invariants and Infor-mation Quantities, W. S. Matheson (U.Essex, Colchester, Essex, England); IEEETrans. Comput. (Short Notes), vol. C-20, pp.691-694, June 1971.

The switching variables in a switchingcircuit are considered as binary randomvariables. The input signals are given jointprobabilities, from which the output signals'probabilities are known. The joint entropy,or average information content, of subsetsof variables is defined, and a proof is giventhat a set of these entropies are characteristicinvariants of the PCN equivalence classes.

9061Gate-Interconnection Minimization of Switch-ing Networks Using Negative Gates, T.Ibaraki (Kyoto U., Kyoto, Japan); IEEETrans. Comput. (Short Notes), vol. C-20,pp. 698-706, June 1971.

In this note an algorithm to design a two-level switching network composed of nega-tive gates with no fan-in restriction imposedon them is developed. The resulting networkis such that it minimizes the cost functionh(G, I), a monotone nondecreasing functionof G and I, where G is the total number ofgates and I is the total number of intercon-nections in the network. In other words, theearlier work is generalized so that the numberof interconnections may be included in itscost criterion. The algorithm is then extendedto the multiple output network design.

9062Chow Parameters in Threshold Logic, R. 0.Winder (RCA Labs., Princeton); J. Ass.Comput. Mach., vol. 18, pp. 265-289, Apr.1971.

This paper is a broad treatment of Chowparameters-a set of n+1 integers whichcan be abstracted from any given n-argumentswitching function. Basic properties andalternative definitions of these numbers areestablished and correlated with several earlierwork in the subject. The main results are asfollows: The class of "unique" functions-those with unique Chow parameter N-tuples-lies properly between the classes of thresh-old functions and the class of completelymonotonic functions. The class of "extremal"

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IEEE TRANSACTIONS ON COMPUTERS, NOVEMBER 1971

functions-with locally minimal or maximalsingle parameters-lies properly between theclass of unique functions and the class ofunate functions (and these inclusions cannotbe tightened in terms of other k-mono-tonicities). A closely related question recentlyraised is settled. Quadratic bounds and aninfinite family of linear bounds, all tight, areobtained. A smooth well-behaved surfaceexists which encloses only the Chow param-eters of nonthreshold functions and whosetangent hyperplanes define realizations of thefunction whose parameters lie outside thepoint of tangency.

9063Cascaded Multithreshold Networks, S. Ghosh(Jadavpur U., Calcutta, India) and A. K.Choudhury (U. Calcutta, India); IEEETrans. Comput., vol. C-20, pp. 655-662, June1971.

Any switching function can always berealized by a single multithreshold elementpossessing a suitable number of thresholds.However, the practical realization of suchelements often presents serious difficulties;as such it becomes more convenient to realizethe given function in the form of a network ofmultithreshold threshold elements, eachpossessing fewer thresholds. In this paper, athorough study of these networks with differ-ent modes of interconnection has been made.These discussions have been limited to con-stant weight (CW) networks only. Finally, atechnique for obtaining the three-thresholdnetwork configuration for an arbitrary k-threshold function has also been suggested.It has been assumed that feedback loops areabsent.

9064A Grammatical Characterization of One-WayNondeterministic Stack Languages, M. E.Harrison and M. Schkolnick (U. Calif.,Berkeley); J. Ass. Comput. Mach., vol. 18,pp. 148-172, Apr. 1971.

A new family of grammars is introduced.A grammatical characterization of the one-way nondeterministic stack languages is ob-tained. Characterizations of the languagesaccepted by nonerasing stack automata andby checking automata are also derived.

9065An N Log N Algorithm for Minimizing Statesin a Finite Automaton, J. Hopcroft (StanfordU., Calif.); Rep. STAN-CS-80-190, 15 pp.,Jan. 1971; CFSTI, AD 719 398, $3.00.

An algorithm is given for minimizing thenumber of states in a finite automaton or fordetermining if two automata are equivalent.The asymptotic running time of the algorithmis bounded by kn log n where k is some con-stant and n is the number of states. The con-stant k depends linearly on the size of theinput alphabet.

9066Information Processing and Transmission inCellular Automata, E. R. Banks (M.I.T.,Cambridge); Rep. MAC-TR-81, 102 pp.,Jan. 1971; CFSTI, AD 717 951, $3.00.A cellular automation is an iterative

array of very simple identical informationprocessing machines called cells. Each cellcan communicate with neighboring cells. Atdiscrete moments of time the cells can changefrom one state to another as a function of the

states of the cell and its neighbors. Thus on aglobal basis, the collection of cells is char-acterized by some type of behavior. The goalof this investigation was to determine justhow simple the individual cells could bewhile the global behavior achieved somespecified criterion of complexity, usually theability to perform a computation or to repro-duce some pattern. The chief result describedis that an array of identical square cells (intwo dimensions), each cell of which communi-cates directly with only its four nearest edgeneighbors and each of which can exist in onlytwo states, can perform any computation.This computation proceeds in a straightfor-ward way.

9067Deterministic Pushdown Store Machines andReal-Time Computation, S. N. Cole (IBM,Owego); J. Ass. Comput. Mach., vol. 18, pp.306-328, Apr. 1971.A comparison is made of the computing

capabilities of deterministic push-down storemachines and real-time iterative arrays offinite-state machines. The main result is thatevery deterministic push-down store com-putation can be performed by some (multi-dimensional) iterative array in real-time. Thelatter are strictly more powerful since they canrecognize the set of palindromes in real time,which deterministic push-down store ma-chines cannot do even if permitted unlimitedcomputing time. During the development ofthe main; result, variants of push-down storemachines, the tabulator machines, and the n-dimensional push-down store machines, areintroduced. By imposing a real-time con-straint and letting the number of tabs and thenumber of dimensions vary, an infinitehierarchy of push-down store (deterministiccontext-free) languages is obtained.

9068Feedback in Homomorphic Realizations, B. P.Zeigler (U. Michigan, Ann Arbor); IEEETrans. Comput. (Short Notes), vol. C-20, pp.685-688, June 1971.

It is known that for every integer d thereare transition functions not isomorphicallyrealizable by any net having feedback indegree(the largest number of wires that any delayreceives from other delays in its feedbackloop) less than d. It is shown that, in contrastto the isomorphic case, every transition func-tion can be homomorphically realized by netsof feedback indegree not exceeding 2. This is aleast upper bound, since simple nets (i.e.,those having feedback indegrees not exceeding1) are shown not to be universal in this sense.

9069Inessential Errors in Sequential Machines,C. Harlow (U. Missouri, Columbia) andC. L. Coates, Jr., (U. Texas, Austin); IEEETrans. Comput. (Short Notes), vol. C-20, pp.688-690, June 1971.

Hartmanis and Stearns defined the con-cept of an inessential error in their study oferrors in sequential machines and representedsuch errors by means of an error partition HE.Although they showed that IIE could not bedetermined using only the usual partitionpair algebras, they did not provide a meansby which it could be determined. The purposeof this note is to develop an algorithm for thedetermination of IIE for a given machine.

9070A State Assignment Procedure for Asyn-chronous Sequential Circuits, G. K. Maki(U. Idaho, Moscow) and J. H. Tracey (U.Missouri, Rolla); IEEE Trans. Comput.-(Short Notes), vol. C-20, pp. 666-668, June1971.

This paper presents a new procedure forconstructing nonuniversal shared-row internalstate assignments for asynchronous sequentialcircuits. The method consists basically ofestablishing an initial code with the minimumnumber of variables required to distinguishthe states. Then variables are systematicallyadded until a satisfactory assignment is ob-tained. State variables added in the expansionof an assignment are merely the EXCLUSIVE ORof state variables in the original assignment.This simple construction procedure termi-nates with a maximum of m+[m/2] statevariables for a 2m-row flow table.

Heuristic Algorithm for Testing AsynchronousSequential Logic Circuits-see 9075.

2) DIGITAL COMPUTERSAND SYSTEMS

9071Scaling Machine Arithmetic, M. L. Stein andW. D. Munro (U. Minnesota, Minneapolis);IEEE Trans. Comput. (Short Notes), vol. C-20, pp. 675-678, June 1971.A general approach to the problem of

scaling machine arithmetic is developed. Thisleads to the determination of inequalities thatcan serve as a basis for the derivation of sys-tematic scaling techniques. The inequalitiesand techniques are shown to apply to com-plement arithmetic with either integral orfractional machine operations and to absolutevalue and sign arithmetic for both types ofoperations. A detailed discussion is presentedfor the case of complement integer arithmetic.The connections with floating-point arith-metic are derived.

9072Serial Adders with Overflow Correction, R. 0.Berg (Honeywell, Minneapolis) and L. L.Kinney (U. Minnesota, Minneapolis); IEEETrans. Comput. (Short Notes), vol. C-20, pp.668-671, June 1971.

A method of implementing two single-bitadders is discussed. These adders can be usedindividually to realize the conventional func-tions of serial addition and serial multiplica-tion on a pair of operands, or they can becascaded to allow the serial addition of threeoperands for forming the product of complexnumbers. In either case, the circuits willdetect the occurrence of an overflow or thegeneration of the number minus 1, and theywill allow an addition to be rescaled by out-putting the correct bits during the additionalshifts, whether the addition overflowed or not.

9073A Binary Multiplication Scheme Based onSquaring, T. C. Chen (IBM, San Jose); IEEETrans. Comput. (Short Notes), vol. C-20, pp.678-680, June 1971.

Using the formula A *B = [(A +B)/2]2- [(A -B)/2]2, the binary multiplication prob-lem is reducible to that of decomposing thesquare of PO P1P2 ... pk into a sum of twoor three quantities. For the eight-bit case, astudy of the multiplication parallelogram

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ABSTRACTS OF CURRENT COMPPUTER LITERATURE

suggests p2=R+S+T, where pi and p8appear only in R, and p2, p, appear only in Rand S. Each bit in T involves the oRing of nomore than four terms, each involving no morethan four Boolean variables. For a two-inputadder, S and T are combined into a six-vari-able problem, where each bit may have up to14 terms. The six- and four-bit problems aredegenerate cases with R = 0 and R =S=0,respectively.

9074Fault Diagnosis of Digital Systems-A Re-view, R. G. Bennetts and D. W. Lewin (TheUniversity, Southampton, England); Comput.J., vol. 14, pp. 199-206, May 1971.

The increasing complexity of digital sys-tems over the past decade has been accom-panied by a growing awareness of the need forefficient fault diagnosis, as proved by the everincreasing literature published on the subject.This paper is based on 86 referenced sourcesand its main function is to review the pub-lished methods of deriving diagnostic testsequences, indicating the advantages and dis-advantages of each technique. In so doing, ittraces the interaction between the diagnostictechniques that have evolved and their in-fluence on the design philosophy of digitalsystems at all levels. It is apparent from thereview that there exists a requirement for aunified theory of diagnosis compatible with,and complementary to, current design tech-niques based on switching theory, and waysare suggested by which this might be achieved.

9075A Heuristic Algorithm for the Testing ofAsynchronous Circuits, G. R. Putzolu andJ. P. Roth (IBM, Yorktown Heights); IEEETrans. Comput., vol. C-20, pp. 639-647, June1971.

This paper describes an algorithm for thecomputation of tests to detect failures inasynchronous sequential logic circuits. It isbased upon an extension of the D-algorithm.Discussion of experience with a program ofthe procedure is given.

9076The Design of a Class of Fast Fourier Trans-form Computers, M. J. Corinthios (U.Toronto, Ont., Canada); IEEE Trans. Com-put., vol. C-20, pp. 617-623, June 1971.

The design of a class of special-purposecomputers for time-series analysis by Fouriertransformation is described. The computersare sequential machines which implementmachine-oriented fast Fourier transformalgorithms obtained by factoring the discreteFourier transform to an arbitrary radix. Achoice of the degree of parallelism in machinearchitecture is made possible by selecting aproper radix r for implementation. Through-out the iterations these algorithms call foraccessing or storing data which are alwaysNlr words apart, where N is the record size.Thus it is possible to partition the data into rqueues, to the tops of which the arithmeticunit is hard-wired. Moreover, two of the im-plemented algorithms yield properly orderedFourier coefficients without the need for pre-or post-ordering data. This is accomplishedby including a simple shuffle operation as aninherent part of the feedback ofeach iteration.The processing speed and maximum samplingfrequency for real-time operation are specified.It is shown that, with present day tech-

nology, a radix-4 machine would performreal-time spectrum analysis of 4096 pointrecords sampled continuously at a rate of onemillion samples per second.

9077Research in Store and Forward Computer Net-works, H. Frank (Network Analysis Corp.,Glen Cove); 95 pp., Jan. 1971; CFSTI, AD719 416, $3.00.

The report discusses the relationship be-tween traffic, routing, throughput and cost instore-and-forward computer networks. Apowerful set of computer programs tooptimize cost and performance is describedand the results of a study to derive estimatesof optimum performance for specified net-works are discussed. The tradeoffs betweencost and throughput as a function of thenumber of nodes in the network are dis-played, and the substantial cost advantages oflarge computer-communication networksdemonstrated.

3) LOGIC DEVICES ANDCIRCUITS (HARDWARE)

Gate-Interconnection Minimization of Switch-ing Networks Using Negative Gates-see 9061.

Design of an Associative Memory Using Push-Down Lists and LSI-see 9078.

4) DIGITAL STORAGE AND INPUT-OUTPUT EQUIPMENT

9078Design of an Associative Memory, W. K. King(U. Houston, Houston); IEEE Trans. Com-put. (Short Notes), vol. C-20, pp. 671-674,June 1971.

An associative memory system usingpush-down or first-in first-out (FIFO) lists asits basic building elements is described. Withthe development of large-scale integrationtechnology (LSI), it is expected that deviceswith regular repetitive structure and highgate/interconnection ratio can be manu-factured at extremely low cost. Push-downand FIFO evidently belong to that category.The logic design of a push-down and a FIFOlist memory are first described. Then, withsome additional control logic, it is shown thatthey can be converted to an associativememory.

9079Modeling the Video Graphics System: Pro-cedure and Model Description, T. E. Bell(Rand Corp., Santa Monica); Rep. R-519-PR, 93 pp., Dec. 1970; CFSTI, AD 718 088,$3.00.

The report presents both the process andresults of generating a computer systemdescription for simulation purposes whileboth hardware and software are under devel-opment. The interactive multiterminal VideoGraphics System achieves low cost by using asterminals modified television sets whose pic-tures are continuously refreshed from a videodisk by three scan converters driven by asingle digital-to-analog converter. An IBM1800 process controller receives graphicorders from user programs in the connectedservice machines (IBM 360's) and sends themto the converter; it also handles input fromterminals. The documentation history details

the activities and elapsed time of each phaseof the 57-week effort; it can serve as an aid inestimating the investment required for such anundertaking, and the conclusions can helpsimulators to document and model moreeffectively.

9080A System for Stereo Viewing, A. Ortony(Imperial College, London, England); Com-put. J., vol. 14, pp. 140-144, May 1971.

This paper describes a system for the view-ing of stereoscopic pairs produced on a CRT.The system is cheap and reliable and con-veniently allows several viewers to simul-taneously perceive 3D objects in depth. It hasproved to be very useful as an aid to under-standing unfamiliar structures generated onthe display and provides a powerful toolparticularly when coupled with hidden lineremoval.

5) PROGRAMMING OF DIGITALMACHINES

9081Research in Computer-Assisted Documentationof Computer Programs. Volume 2, E. C.Berkeley (Berkeley Enterprises Inc., New-tonville); Rep. 8-230/71, 113, pp., Dec. 1970;CFSTI, AD 719 451, $3.00.

The purpose of the research is to discoverand develop methods and principles by meansof which a computer program which has littleor no documentation can be easily docu-mented by a human programmer with theassistance of a computer. The report: dis-cusses the problem of documentation of com-puter programs; presents a further model of a"Simulator Analyzer" computer programwhich simulates a computer and analyzes anundocumented working binary program;presents a computer program which expressesthis simulator analyzer; demonstrates howthis works on some simple examples; dis-cusses comments and mnemonic symbols incomputer programs and principles for ab-breviating, and suggests some preferred ab-breviations; discusses relocation of a workingbinary program without knowing how itworks; and presents a successful relocation ofa working binary program for a dynamicdebugging program without knowing thesymbolic program from which it was as-sembled.

9082Information Distribution Aspects of DesignMethodology, D. L. Parnas (Carnegie-MellonU., Pittsburgh); AFOSR-TR-71-0547, 26 pp.,Feb. 1971; CFSTI, AD 719 863, $3.00.

The role of documentation in the designand implementation of complex systems isexplored, resulting in suggestions in sharpcontrast with current practice. The concept ofsystem structure is studied by examining themeaning of the phrase "connections betweenmodules." It is shown that several systemdesign goals (each suggesting a partial timeordering of the decisions) may be inconsistent.Some properties of programmers are dis-cussed. System documentation, which makesall information accessible to anyone workingon the project, is discussed. The thesis thatsuch information "broadcasting" is harmful,that it is helpful if most system information ishidden from most programmers, is supported

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IEEE TRANSACflONS ON COMPUTERS, NOVEMBER 1971

by use of the above mentioned considerationsas well as by examples. An information hidingtechnique of documentation is given in theappendix.

9083The BRLESC II hstruction Code, G. A. Beck(Aberdeen Res. and Develop. Cen., AberdeenProving Ground); Rep. ARDC-TR-8, 56 pp.,Feb. 1971; CFSTI, AD 719 694, $3.00.

BRLESC II is a large, high speed, elec-tronic computer that is now in operation atARDC. It was built to supplement theBRLESC I computer which has been operat-ing since 1960. The report is intended to aidprogrammers in writing assembly languageprograms for applications which cannot bedone using the Fortran language and, in somecases, to aid in determining the cause whenFortran programs fail to execute as expectedby the programmer. A description of each ofthe 115 executable instructions is given from aprogramming point of view. That is, a descrip-tion is given of what is done, not how it isdone.

9084How to Keep the Addresses Short, D. L.Richards (Leasco Systems Corp., Tustin);Commun. Ass. Comput. Mach., vol. 14, pp.346-348, May 1971.

An algorithm is presented for minimizingthe sum of the lengths of the blocks of codingproduced by an assembler or compiler when:1) the length of each computer instruction isassumed to be either "long" or "short"("long," if the memory location addressed ismore than a predetermined distance from thecurrent location; "short", otherwise); and 2)there are blocks of instructions whose begin-nings (origins) are separated by prespecifiedamounts. For example, some computerspermit either 8-bit addressing (interpretedrelative to the location counter) or full 16-bitaddressing of all of memory. When assemblingor compiling two or more blocks of instruc-tions which have many mutual references insuch a computer, there is no simple iterativeprocedure for keeping as many of the ad-dresses as short as possible. This paper dem-onstrates that a wide class of problems ofthis type can be formulated as covering prob-lems solvable by means of elementaryarithmetic operations on the column vectorsof a ternary matrix.

9085On Implementation of Label Variables, R. R.Fenichel (M.I.T., Cambridge); Commun.Ass. Comput. Mach., vol. 14, pp. 349-350,May 1971.

Variables of label mode are conventionallyimplemented with a technique which faiis totrap certain programming errors. Fine-grained calendar clocks have recently becomeavailable; these allow implementation oflabel variables via a new technique whichtraps all programming errors of this variety.

9086Slave Memories and Segmentation, M. V.Wilkes (U. Cambridge, Cambridge, England);IEEE Trans. Comput. (Short Notes), vol. C-20, pp. 674-675, June 1971.

It is pointed out that in a computer pro-vided with multiple base-limit registers a slaveor buffer memory may be used to reduce timespent in address validation and relocation, as

well as for its normal purpose of reducingmemory access time.

9087Probability Models for Buffer Storage Alloca-tion Problems, D. P. Gaver, Jr., (Carnegie-Mellon U., Pittsburgh) and P. A. W. Lewis(IBM, Yorktown Heights); J. Ass. Comput.Mach., vol. 18, pp. 186-198, Apr. 1971.

This paper considers some of the issuesthat arise when messages or jobs inbound to acomputer facility are buffered prior to beingprocessed. Models are developed that de-scribe: 1) the results of blocking a singlememory unit for the use of diverse messages;2) the occupancy behavior of a buffer that istied to a single message source; and 3) theoccupancy of a buffer dynamically sharedamong many independent sources.

9088An ALGOL Line-Syntax Checker, E. W.Hadden (U. East Anglia, Norwich) andL. G. Proll (U. Southampton, Southampton,England); Comput. J., vol. 14, pp. 128-132,May 1971.

This paper describes a facility for partiallychecking the syntax of a line of an Algolprogram as it is input to a computer from aremote input device.

9089SOAP-A Program Which Documents andEdits ALGOL 60 Programs, R. S. Scowen, D.Allin, A. L. Hillman, and M. Shimell (Nat.Phys. Lab., Teddington, Middlesex, England);Comput. J., vol. 14, pp. 133-135, May 1971.

This paper describes a program calledSOAP (simplify obscure Algol programs)which reads an Algol 60 program as data,cleans it up, and outputs it in a form whichclarifies its structure, thus making it easier tounderstand. The paper states some of theadvantages of using SOAP and specifies thelayout of an edited program. SOAP iS anAlgol 60 procedure.

9090Extensible Language Research, T. A. Standishand E. L. Wegbreit (Harvard U., Cambridge);ESD-TR-70-442, 20 pp., Nov. 1970; CFSTI,AD 719 762, $3.00.

The report summarizes work performedat Harvard on the design and implementationof programming languages and programminglanguage techniques for handling multipledata types. A prototype language called thepolymorphic programming language has beenimplemented at Harvard and features datadefinition facilities and operator extensions.The report summarizes the experience gained,using this language, particularly with regardto the verification of the usefulness of datadefinition techniques in programming. Thereport also discussed unsolved problems inlanguage design and points toward areas forfurther investigation.

9091Interpreter Techniques for the GE-600, P.Barbe (Probe Consultants Inc., Phoenix);Rep. PLR-004, 15 pp., Aug. 1970; CFSTI, AD719 390, $3.00.

The interpreter is the first phase of thePILER system of automatic translation ofcomputer programs from one machine lan-guage to another. This report describes theimplementation of an interpreter for the GE-

600 computer. Because the operating systemis an integral part of the hardware-operatingprogram interface in this computer, certaininformation regarding the functions of thesubject program can be extracted from theoperating system. Elementary analysis is per-formed by the interpreter to locate this in-formation. The interpreter decodes instruc-tions, identifies I/O parameter lists, I/Obuffers, subroutine parameters and callingsequences, and other data. All information isprepared in microform format for input to thePILER analyzer.

Proofs About Interpreters for ProgrammingLanguages-see 9057.

9092Intermediate Language in the PILER System,P. Barbe (Probe Consultants Inc., Phoenix);Rep. PLR-005, 18 pp., Feb. 1971; CFSTI, AD719 391, $3.00.

The PILER system is an automatic com-puter program translator which translates asource machine language program to aspecified language for the target computer.The three steps in the translation are inter-pretation of subject program commands,analysis of subject program for function andpurpose and data forms, and conversion ofthe subject program to the target language.The report describes the intermediate lan-guage which is the language used to transmitinformation from the analyzer to the con-verter. This is not a formal programminglanguage, but an internal communicationcode. The intermediate language consists ofthree elements: the logic framework whichdetails the program flow paths; the impera-tive statement list which describes proceduresto be performed; and the data description,which describes the format and usage of dataitems.

9093Compiler Design for the ILLIAC IV, R. E.Millstein (Mass. Computer Ass., Inc., Wake-field); 72 pp., Jan. 1971; CFSTI, AD 719 417,$3.00.

The Illiac Fortran compiler may becharacterized as a series of transformations onthe source input stream. Fortran code is trans-formed into a representation which exploitsIlliac parallelism. This transformation isaccomplished by detecting individual state-ments within DO loops which may be executedin parallel for values of the DO indices, anddetermining an ordering which preserves datadependencies. While the result of this effortaffords Illiac parallelism, it is insensitive totwo major characteristics of Illiac hardware;an enormous disk latency, and an ability tooverlap execution of sequential and parallelcomponents of the hardware. In order tofully exploit the capabilities of the Illiac, twomore transformations are effected. First, codeis restructured to minimize the effect of disklatency. Second, operations are allocated tomaximize CUPE overlap. At this stage it isappropriate to generate Illiac code.

Recursion Induction Principle for ProvingCompiler Correctness-see 9057.

9094Computer Operating Systems Capabilities: ASource Selection and Analysis Aid, W. C.Mittwede (Comtre Corp., Coral Gables);

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ABSTRACTS OF CURRENT COMPUTER LITERATURE

ESD-TR-71-74, 267 pp., Nov. 1970; CFSTI,AD 718 973, $3.00.

The report presents a method for translat-ing operational data processing requirementsinto specific criteria for use in selecting,validating, or evaluating computer operatingsystems. The criteria have been structured onthe basis of an integrated functional classi-fication structure applicable to the executive/control functions, system management func-tions, and data manipulation functions ofcurrently available operating systems. In con-cert with the methodology presented, a check-list form is included as an aid to developingselection criteria for particular applications. Adiagram of the functional classification struc-ture is also included.

9095Program Suitability for Parallel Processing,M. J. Gonzalez, Jr., and C. V. Ramamoorthy(U. Texas, Austin); IEEE Trans. Comput.,vol. C-20, pp. 647-654, June 1971.

This paper describes the Fortran paralleltask recognizer and the directed graph modelupon which it is based. The recognizer is itselfa Fortran program. As input the recognizeraccepts source programs written in Fortran;as output the recognizer generates a set oftables which communicate to the operatingsystem information regarding the parallelprocessability of source program tasks. Therecognizer has been used to analyze severalprograms in an attempt to determine whatcharacteristics render a program "suitable"for parallel processing. Timing studies haveshown that the detailed recognizer analysisconsumes a large amount of time in an at-tempt to answer the suitability question. For asuitable production-type program this analysistime can be distributed over the lifetime of theprogram. In those cases where the sourceprogram is not suitable for parallel process-ing, however, this analysis represents awasted investment of valuable system re-sources. To circumvent this, a heuristicprocedure has been developed which intro-duces little overhead and provides a pre-liminary answer to the suitability questionbased solely on the nature and number ofsource program statements. If the preliminaryanalysis suggests a favorable potential for thesource program, then the program is subjectedto the detailed analysis of the recognizer.

9096A Cyclic-Queue Model of System Overhead inMultiprogrammed Computer Systems, P. W. A.Lewis (IBM, Yorktown Heights) and G. S.Shedler (IBM, San Jose); J. Ass. Comput.Mach., vol. 18, pp. 199-220, Apr. 1971.A probabilistic model is presented of a

multiprogrammed computer system operatingunder demand paging. The model contains anexplicit representation of system overhead,the CPU requirements and paging charac-teristics of the program load being describedstatistically. Expressions for steady-state CPUproblem program time, CPU overhead time,and channel utilization are obtained. Somenumerical results are given which quantifythe gains in CPU utilization obtained frommultiprogramming. It is also pointed outheuristically and demonstrated numericallythat an actual decrease in CPU utilization re-sults if there is too much overhead associatedwith multiprogramming and if the averagetime between page exceptions decreases too

rapidly with an increasing number of multi-programmed jobs.

Security Techniques in MultiprogrammingMultiprocessing Systems-see 9053.

9097Busy Period Analysis of a Time-Sharing Sys-tem Modeled as a Semi-Markov Process,U. N. Bhat and R. E. Nance (Inst. Tech.,Southern Methodist U., Dallas); J. Ass.Comput. Mach., vol. 18, pp. 221-238, Apr.1971.

Several authors have analyzed computertime-sharing systems from the user's per-spective waiting time in the system and ex-pected number of tasks in queue. In contrast,the busy period analysis is oriented towardthe operator's perspective effective utilizationof the central processing unit. Working fromthe model of task completions as a semi-Markov process, the busy period distributionof the central processor is derived in terms ofits Laplace-Stieltjes transforms. Limiting be-havior of the process describing the number oftasks in queue is developed for arbitrary timepoints as well as task completion epochs.While the latter has been given in earlierpapers, the former represents a new result. Ofsignificance is the fact that the limiting be-havior for number of tasks in queue atarbitrary time points is not reflected in thelimiting behavior at task completion epochs.Calculation of the transform values is en-hanced by the development of an efficientcomputational structure. To illustrate thecomputational procedure, the limiting be-havior of the time-sharing system is investi-gated. Changes in system behavior are notedas the number of peripheral units is increasedand the quantum length is varied. The numberof peripheral units that can be added beforesaturating the central processing unit is animmediate result. For the specific test cases, aquantum length of approximately one-half themean processing time for each job producesacceptable values for the expected busy periodand the limiting behavior for the number oftasks in queue.

9098Multi-Access on the Chilton Atlas, J. C.Baldwin and R. E. Thomas (Atlas ComputerLab., Chilton, Didcot, Berkshire, England);Comput. J., vol. 14, pp. 119-122, May 1971.

Multiaccess facilities have been providedon the Chilton Atlas without degradation ofthroughput by use of a satellite computer. Thesatellite, an XDS Sigma 2, is attached to themain machine in two distinct ways: directly,by means of a peripheral link (i.e., appearingas a paper tape reader/punch), and in-directly, via a large disk file. A filing system(absent from the Atlas operating system) hasbeen implemented on the Sigma 2 and provi-sion is made for Atlas jobs to be initiatedusing these files. No real-time interaction ispossible with a job running on Atlas, but out-put from the completed job may be directedback into the filing system for inspection atthe user's terminal.

9099Approaches to Conversational FORTRAN,D. W. Barron (The University, Southampton,England); Comput. J., vol. 14, pp. 123-127,May 1971.

This paper defines the term "conversa-tional programming system" in a pragmatic

way by considering the facilities that the userexpects to see in such a system. The difficultiesof implementation are discussed, in the con-text of developing an outline design for a con-versational Fortran system that makes areasonable compromise between flexibilityand efficiency.

9100Blocking Sequentially Processed MagneticFiles, S. J. Waters (LSE, London, England);Comput. J., vol. 14, pp. 109-112, May 1971.

This paper develops a mathematicalalgorithm that enables block sizes to besystematically calculated for sequentiallyprocessed magnetic files. A computer systemsdesigner should find the algorithm simple toapply manually, once understood, and it isbeing programmed into experimental designsoftware, which, to a large extent, automat-ically designs and optimizes a computersystem for minimum cost.

9101FOCUS-A Remote Access File HandlingSystem On-Line to a CDC 6000 Series Com-puter, D. Ball, P. M. Blackall, V. Gerard,G. R. Macleod, P. J. Marcer, and E. M.Palandri (CERN, Geneva, Switzerland);Comput. J., vol. 14, pp. 113-118, May 1971.

The paper describes a system to providemultiaccess facilities for file creation, storage,and manipulation on a medium-sized com-puter, together with remote job submission toa large batch processing computer. Withinthis framework, the system also provides filefacilities for the accumulation of sample datafrom a number of remote process controlcomputers which acquire data in real time inphysics experiments and which are connectedto the file handling machine by very highspeed data links. The system has been entirelyimplemented at CERN on a CDC 3100 com-puter connected to a CDC 6600 computer anda CDC 6500 computer.

9102Some Properties of the Scatter Storage Tech-nique with Linear Probing, J. Kral (Inst.Comput. Tech. CVUT, Horska, Praha,Czechoslovakia); Comput. J., vol. 14, pp. 145-149, May 1971.

Let M(n, k) be (for a scatter storage tech-nique) the average number of probes neces-sary to find an item in a table T of length ncontaining k items. Some identities allowingone to compute M(n, k) for the scatter storagetechnique with linear probing for various nand k are given. From the behavior ofM(n, k), an asymptotical formula given inMorris follows. For n_.1024 and k/n_0.8the values of M(n, k) are practically equal tothe corresponding asymptotical values. Acomparison with some other scatter storagemethods is made. It is shown that in manycases the linear probing method is the bestone.

9103APL/1500 File Access Subroutine Package,T. D. McMurchie and D. B. Thomas (FloridaState U., Tallahassee); Rep. CAI-SystemsMemo-10, 32 pp., Feb. 1971; CFSTI, AD 717928, $3.00.

The APL/1500 file-access subroutinepackage is a self-contained collection ofrelated subroutines which provide users ofAPL/1500 Fortran and assembly language

1425

IEEE TRANSACTIONS ON COMPUTERS, NOVEMBER 1971

systems with the ability to manipulate thedata in APL/1500 disk files. The subroutinepermit off-line access to data generatedthrough instructional and research applica-tions of the system. A description of the use ofthe film-access subroutines, and a listing andexecution of a sample Fortran program whichaccesses existing APL/1500 files is included.

9104Introduction to "Feature Analysis of Gener-alized Data Base Management Systems,"Codasyl Syst. Committee; Commun. Ass.Comput. Mach., vol. 14, pp. 308-318, May1971.

This paper is a separately published intro-duction to a main report which analyzes thefeatures of generalized data base managementsystems. This introduction gives a review ofthe current state of the art in these systemsand discusses the differences and similaritiesbetween capabilities found in host languagesystems and those found in self-containedsystems. After some discussion of the prob-lems of data independence and binding, thefour user levels are identified and described.Technical problems facing future designersare described. The first of these is that ofhandling existing stored data and the next isthat of providing more complex data struc-tures than those already available in conven-tional programming languages. The problemof high level interrogation and update func-tions acting on network structures is men-tioned, followed by a discussion of the prob-lem of catering to a high volume of transac-tions initiated from terminals by parametricusers, the lowest level of user. The use ofCobol as a basis for further developmentwork is considered at some length with re-spect to data structures, host languagecapabilities, and self-contained capabilities.This section also assesses the effect of the DataBase Task Group proposals. The final sectionoutlines the ten major topics in the main bodyof the full report.

9105Continuous Shading of Curved Surfaces, H.Gouraud (U. Utah, Salt Lake City); IEEETrans. Comput., vol. C-20, pp. 623-629, June1971.A procedure for computing shaded pic-

tures of curved surfaces is presented. Thesurface is approximated by small polygons inorder to solve easily the hidden-parts prob-lem, but the shading of each polygon is com-puted so that discontinuities of shade areeliminated across the surface and a smoothappearance is obtained. In order to achievespeed efficiency, the technique developed byWatkins is used which makes possible a hard-ware implementation of this algorithm.

9106Generation of Halftones by Computer-Con-trolled Microfilm Recorder, L. Rossol (Gen-eral Motors Res. Labs., Warren); IEEETrans. Comput. (Short Notes), vol. C-20, pp.662-664, June 1971.

Computers, in conjunction with microfilmrecording equipment, are capable of generat-ing pictures with a reasonable number of graylevels and good resolution. A method isdescribed for producing pictures by means ofhalftone dot patterns using such equipment.The method is relatively insensitive to varia-tions in hardware performance and adjust-ments.

6) LINGUISTICS, DOCUMENTATION,AND HUMANITIES

9107The Relational Data File and the DecisionProblem for Classes of Proper Formulas,R. A. DiPaola (Rand Corp., Santa Monica);Rep. R-661-PR, 28 pp., Feb. 1971; CFSTI,AD 719 752, $3.00.

In connection with Rand's relational datafile, the class of proper formulas has beenproposed as comprising those formalizationsof questions to be processed by the RDF thatare especially suitable for machine processing.The subclasses of proper formulas depend onthe identity of the logical primitives employed.Different sets of primitives give rise to differ-ent classes of proper formulas. In this reportit is shown that the decision problem issolvable for: 1) the class of proper prenexformulas (on any set of primitives); 2) theclass of proper formulas on negation, disjunc-tion, and existential quantification; 3) theclass of proper formulas on negation, im-plication, and existential quantification; and4) the class of proper formulas on negation,disjunction, implication, and existential quali-fication. Thus, for each of these classes thereis a mechanical decision procedure that deter-mines if an arbitrary formula (on the relevantset of primitives) is a member of the class.

9108Toward Direct Access Intelligence Systems,H. V. Foerster (Illinois U., Urbana); AFOSR-70-2991TR, 27 pp., Dec. 1970; CFSTI, AD718 062, $3.00.

In contrast to conventional so called"information storage and retrieval systems,"which de facto store indexed documents (thedata base) that upon retrieval may or may notcontain the information needed by the querierwho is to address such systems through highlyrestricted and artificial indexing languages,this project aims at the development of a database which organizes the intelligence stored ina machine such that the desired knowledge isdirectly accessible to the user through a man-machine dialogue in the user's natural lan-guage. The feasibility of this approach todirect-access intelligence systems (DAIS) isstrongly indicated by recent results obtainedby various investigators in the development ofrelational data structures and interactingmachine programs which permit computing inthe semantic domain, and in logic, theory, andexperimental studies of cognitive processes inliving organisms. Consequently, it was pro-posed to continue and to complete the re-search and development of the conceptual,theoretical, and technological foundations forthe development of machine intelligence sys-tems with direct access to a user's desiredknowledge via a man-machine dialogue in theuser's natural language.

Security Techniques for EDP of MultilevelClassified Information-see 9053.

7) BEHAVIORAL SCIENCE, PATTERNRECOGNITION, AND ARTIFICIAL

INTELLIGENCE9109A Distance Criterion for Figural PatternRecognition, A. Vinea (Cen. Econ. Comput.Econ. Cybern., Bucharest, Romania) and V.Vinea (Inst. Electron. and Comput. Tech.,Bucharest, Romania); IEEE Trans. Comput.

(Short Notes), vol. C-20, pp. 680-685, June1971.

The set of transformations which preservethe equivalence classes of figural patterns isconsidered. The simple figure and its abstractdescription in a metric space are defined. Anappropriate distance is proposed to be appliedto pattern recognition. A trainable classifierusing the nearest-neighbor method is de-scribed. Some experiments with printed orhandwritten letters are presented. No statis-tical results are given, but the visual examina-tion of figures that were recognized revealsthat the method successfully imitates humanperformance.

9110Some Parallel Thinning Algorithms forDigital Pictures, R. Stefanelli (Politecnico diMilano, Milan, Italy) and A. Rosenfeld (U.Maryland, College Park); J. Ass. Comput.Mach., vol. 18, pp. 255-264, Apr. 1971.

If a picture contains elongated objects ofdifferent thicknesses, one can make measure-ments on it which are thickness invariant byfirst transforming it so that each object isthinned down to a "medial line" of constantthickness. Several algorithms are describedwhich perform such a thinning transforma-tion when applied to the picture in parallel.It is proved that these algorithms do notchange the connectivity properties of thepicture.

9111On the Optimal Detection of Curves in NoisyPictures, U. Montanari (Instituto di Elabo-razione della Informazione, Pisa, Italy);Commun. Ass. Comput. Mach., vol. 14, pp.335-346, May 1971.A technique for recognizing systems of

lines is presented. In this technique theheuristic of the problem is not embedded inthe recognition algorithm but is expressedin a figure of merit. A multistage decisionprocess is then able to recognize in the inputpicture the optimal system of lines accordingto the given figure of merit. Due to the globalapproach, greater flexibility and adequacyin the particular problem is achieved. The re-lation between the structure of the figure ofmerit and the complexity of the optimizationprocess is then discussed. The method de-scribed is suitable for parallel processing be-cause the operations relative to each state canbe computed in parallel, and the number ofstages is equal to the length N of the curves(or to log2 (N) if the approximate method isused).

9112Networks of Constraints: Fundamental Proper-ties and Applications to Picture Processing,U. Montanari (Carnegie-Mellon U., Pitts-burgh); AFOSR-TR-71-0322, 57 pp., Jan.1971; CFSTI, AD 718 994, $3.00.

The problem of representation andhandling of constraints is considered, mainlyfor picture processing purposes. A systematicspecification and utilization of the availableconstraints could significantly reduce theamount of search in picture recognition. Onthe other hand, formally stated constraintscan be embedded in the syntactic productionsof picture languages. Only binary constraintsare treated, but they are represented in fullgenerality as binary relations. Constraintsamong more than two variables are thenrepresented as networks of simultaneous

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ABSTRACIS OF CURRENT COMPUTER LITERATURE

binary relations. In general, more than oneequivalent (i.e., representing the same con-straint) network can be found; a minimalequivalent network is shown to exist, and itscomputation is shown to solve most practicalproblems about constraint handling. No exactsolution for this central problem was found.Anyway, constraints are treated algebraically,and the solution of a system of linear equa-tions in this algebra provides an approxima-tion of the minimal network. This solution isthen proved exact in special cases, e.g., fortree-like and series parallel networks and forclasses of relations for which a distributiveproperty holds. This latter condition is satis-fied in cases of practical interest.

8) MATHEMATICSNumerical Analysis and Computer Science inRetrospect-see 9052.

9113A System for the Manipulation of Mathemati-cal Expressions with Computers, E. Vogel;Computing, vol. 6, nos. 1/2, pp. 173-190,1970.

This paper describes a system for manipu-lation of mathematical expressions alongheuristic lines (e.g., for formal integration).The system uses stored formulas (to be chosenaccording to the purpose), which form aformula program, where special signs controlthe procedure, depending on the applicabilityof the formulas. A formula language isdefined which allows for automatic analogousextension of formulas, so that, for instance,the formal multiplication of any two (match-ing) matrices can be expressed by one singleformula. Transitions to subroutines forarithmetical operations, simple standard pro-cedures, and so on are easily accomplished bymeans of a special symbol.

9114A General Factorising Algorithm, G. G. Alway(Nat. Phys. Lab., Teddington, Middlesex,England); Comput. J., vol. 14, pp. 166-168,May 1971.A computer algorithm is given for es-

tablishing the primality of large numbers;this is faster than those previously describedand allows a complete check on all thearithmetical processes.

9115On a Class of Systems of Complex IntervalEquations Evaluable with Iteration Methods,0. Mayer; Computing, vol. 6, nos. 1/2, pp.104-106, 1970.

In two previous papers there were de-duced some statements for certain intervalequations over the real number field concern-ing the existence and uniqueness of the solu-tion and the convergence of iteration methodsfor the evaluation of the solution. This papershows how these statements and their proofscan be extended to analogous interval equa-tions over the complex number field.

9116On an Algorithm for Discrete Nonlinear L,Approximation, M. R. Osborne and G. A.Watson (Australian National U., Canberra,ACT); Comput. J., vol. 14, pp. 184-188,May 1970.

An algorithm for discrete nonlinear L,approximation is shown to converge underconditions often assumed in practice. The

application of the algorithm is illustrated bysome examples.

9117Parametric Curve Fitting, M. Grossman(Imperial College, London, England);Comput. J., vol. 14, pp. 169-172, May 1971.

An iterative method is described forleast-squares curve fitting, when both theabscissae and ordinates are subject to error.The ordinate and abscissa are fitted by para-metric functions, using a constructive non-linear optimization procedure. The order ofthe data points is maintained, and hencemultivalued data may be fitted.

9118The Computation of Bounds for the Minimumand Maximum of a Polynomial in an Interval,R. Dussel and B. Schmitt; Computing, vol. 6,nos. 1/2, pp. 35-60, 1970.

With the aid of an errorbound, arithmeticbounds are computed for the minimum andmaximum of a polynomial P(x) in an interval[a, b]. The coefficients of P(x) can be intervalnumbers. To do this the zeros of P'(x) areenclosed in intervals where P(x) is evaluatedin a suitable manner. One gets the zeros ofP'(x) by computing successively the zeros ofP(i-')(x) until P'(x) beginning with a deriva-tion P(i)(x) with P(i)(x)#0. Thereby one usesthe fact that between two zeros of P (i)(x)there is at most one zero of P (-')(x). Thezeros are enclosed in intervals by means of themethod of interval halving.

9119A Note on Iterative Methods Using MonotonicDecomposable Operators, G. Alefeld; Com-puting, vol. 6, nos. 1/2, pp. 161-172, 1970.

By means of monotonic decomposableoperators, Collatz, Albrecht, and Schroderhave considered a variety of iterative methods,by which they get inclusion sets for the solu-tion of systems of simultaneous linear ornonlinear equations, for example. It is shownthat these methods are special cases of basiciterative methods for equations with intervalcoefficients. In the concluding part of thispaper a general convergence theorem in aRieszian-space is given.

9120On the Automatic Numerical Evaluation ofDefinite Integrals, R. Cranley and T. N. L.Patterson (U. Texas, Dallas); Comput. J.,vol. 14, pp. 189-198, May 1971.A critical examination is made of adaptive

subdivision as a means of reliably and effi-ciently performing the automatic evaluationof definite integrals. A model is set up whichembodies the basic features of adaptiveschemes. Circumstances are discussed underwhich adaptive schemes may inspire falseconfidence in the result produced. The effi-ciency of the method is seriously impaired byany attempts to overcome this difficulty. Theconclusions have been illustrated by ap-propriate numerical examples.

9121The Numerical Solution of Implicit FirstOrder Ordinary Differential Equations withInitial Conditions, M. A. Wolfe (U. St.Andrews, England); Comput. J., vol. 14, pp.173-178, May 1971.

Predictor-corrector methods are used inconjunction with iteration to obtain numeri-cal solutions of a class of first-order ordinary

differential equations with an initial conditionin which the derivative cannot be expressedexplicitly as a function of the independentand dependent variables.

9122Optimum Extrapolated ADI Iterative Dif-ference Schemes for the Solution of Laplace'sEquation in Three Space Variables, A.Hadjidimos (The New University of Ulster,Northern Ireland); Comput. J., vol. 14, pp.179-183, May 1971.

This paper describes the application of theextrapolated ADI methods for the numericalsolution of Laplace's equation over the openunit cube under "model problem" boundaryconditions. Three different approximatingdifference formulas are considered and eachone of the resulting extrapolated ADIschemes is treated by using the set of Douglasparameters in two different ways. In additiona comparison of the two methods is made andoptimum extrapolated ADI schemes aregiven.

9123Classical Fourth- and Lower Order Runge-Kutta Formulas with Stepsize Control andtheir Application to Heat Transfer Problems,E. Fehlberg; Computing, vol. 6, nos. 1/2,pp. 61-71, 1970.

New explicit fourth- and lower orderRunge-Kutta formulas are presented. Theseformulas include a stepsize control procedurebased on a complete coverage of the leadingterm of the local truncation error. The formu-las have considerably smaller truncationerrors than corresponding formulas of otherauthors. These new formulas are suitable forthe numerical integration of heat transferproblems after discretization of these prob-lems in the space variables, since stabilityconsiderations, occurring in such problems,would eliminate the benefits, (large per-missible stepsize) of high-order Runge-Kuttaformulas. The formulas are applied to anexample for a heat transfer problem.

9124Elementary Determination of EigenvalueBounds and of Functions Bounding the Solu-tion of Inhomogeneous Ordinary and SingularIntegral Equations of the Second Kind withFixed Limits of Integration, D. Marsal;Computing, vol. 6, nos. 1/2, pp. 80-93, 1970.

The paper deals mainly with the deter-mination of two functions bounding the solu-tion of systems of integral equations with anynumber of free variables. It is assumed thateach kernel is split into a degenerate one anda remainder. If the remainders are notsufficiently small, the result may be improvedby simple iteration. From a numerical pointof view, the method is superior to well-knownmethods of functional analysis.

9125On the Topological Properties of QuantizedSpaces. I. The Notion of Dimension, J. P.Mylopoulos and T. Pavlidis (Princeton U.,Princeton); J. Ass. Comput. Mach., vol. 18,pp. 239-246, Apr. 1971.

An attempt is made to define meaningfulcounterparts of topological notions inquantized spaces. Finitely presented Abeliangroups are used as a model for such spaces.Then the notion of dimension is introducedthrough a recursive definition, and it isproven that for free Abelian groups it equalsthe number of generators.

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IEEE TRANSACIIONS ON COMPPUTERS, NOVEMBER 1971

O,> th lTopological Properties of QuantizedSpaes. II. Connectivity and Order of Con-netivty, J. P. Mylopoulos and T. Pavlidis(Prnceton U., Princeton); J. Ass. Comput..a:k, vol. 18, pp. 247-254, Apr. 1971.A :notion of equivalence (c-equivalence) is

defind as the counterpart of homeomorphismfor quantized spaces. It is shown that setswith the same number of components andholes are c-equivalent in two-dimensional0paces. Then it is shown that for each arbi-trary set there is a set c-equivalent to it withcertain "regular" features (rectangular perim-ter, holes with diameter one, etc.).

9) PROBABILITY, MATHEMATICALPROGRAMMING, DIGITAL SIMULA-TION, INFORMATION THEORY,

AND COMMUNICATIONSYSTEMS

9127'A Note on Fast Cyclic Convolution, Y.-Zalcstein (Carnegie-Mellon U., Pittsburgh);IEEE Trans. Comput., (Short Notes), vol.C-20, pp. 665-666, June 1971.

This note presents a new algorithm forcomputing the cyclic convolution of twovectors over a commutative ring. The algo-fithm requires n(nl+1) ... (nk +1)/2k multi-plications for the convolution of two n-vec-tors, where n1 = n ...**k is a factorization of-n into factors which are pairwise relatively,prime.

9128Genertion of Permutation Sequences: Part 2,R. J. Ord-Smith (U. Bradford, Yorkshire,;England); Comput. J., vol. 14, pp. 136-139,May 1971.

The main purpose of Part 2 is to presentexplicitly the six fastest general permutationalgorithms in an improved and standardizedform. A comparison shows the kind ofdifficulties which can arise in the implementa-tifn of a high-level language. An appendixcontains an extended bibliography. A briefacount ofcontinuing work is included.

9129Sstematic Generation of Ordered Sequencessing; Recurrence Relations, E. S. Page (U.

Newcastle upon Tyne, England); Comput. J.,VWl. 14, pp. 150-153, May 1971.

The calculation of the number of membersf certnin sets can be achieved by analyzing

recurrexce relations. In this note, attentionis dra to the use of such recurrence rela-mions for deriving ordering of the members of

the sets in a systematic way and for answer-gquestions about places in the orderings.

xmples for certain types of restrictedpermutations are given.

Time-Seris Analysis by Fourier Transforma-ne 9076.

.9130-

A Note on a New Divisive Classificatory Pro-gram for Mixed Data, G. N. Lance and W. T.Williams (CSIRO, Brisbane, Australia);Coput. J., vol. 14, pp. 154-155, May 1971.

Algorithms are provided which will definea divisive monothetic classificatory programapplicable to mixed data; this is based on aninformation-statistic model, and is an alter-native to an earlier program based on x2.

9131Some Observations on a Paper by Lance andWilliams, R. Sibson (King's College, Cam-bridge, England); Comput. J., vol. 14, pp.156-157, May 1971.

This paper presents criteria which areconsidered essential for any general clusteringalgorithm and shows that the algorithm ofLance and Williams fails to satisfy these.

9132Group-Size Dependence: A Rationale forChoice Between Numerical Classifications,W. T. Williams (CSIRO, Queensland, Aus-tralia), H. T. Clifford (U. Queensland, St.Lucia, Queensland, Australia), and G. N.Lance (CSIRO, Canberra City, Australia);Comput. J., vol. 14, pp. 157-162, May 1971.

The problem of erecting criteria for choicebetween numerical classifications is brieflysurveyed; it is concluded that the most diffi-cult case arises in the synoptic classificationof highly heterogeneous data, for which apowerful clustering system is essential, andfor which several alternative strategies are incommon use. In all such strategies an inter-group or individual-group measure is de-pendent on the size of the group, but thenature of this dependence has not previouslybeen investigated. It is here investigated forfour widely used strategies, and appropriateconclusions drawn as to their differing ap-plicability to particular types of problems.

9133Controversy Concerning the Criteria forTaxonometric Strategies, W. T. Williams(CSIRO, St. Lucia, Queensland, Australia),G. N. Lance and M. B. Dale (CSIRO, Can-berra City, Australia), and H. T. Clifford(U. Queensland, St. Lucia, Queensland,Australia); Comput. J., vol. 14, pp. 162-165,May 1971.

Recent growth of interest in numericalclassificatory strategies has led to the searchfor criteria which such strategies should ful-fil. Two largely incompatible schools ofthought have now arisen, one in Cambridge,the other in Australia. The article examinesthe differences in the basic premises of theseschools with particular reference to linguisticdifferences and the wider implications of thetwo sets of criteria.

9134Analytical and Interactive Techniques forMultivariate Data Compression and Classifica-tion, R. B. Roper (Systems Res. Labs., Inc.,Dayton); Rep. SRL-60606-F AFCRL-70-0540, 59 pp., Sept. 1970; CFSTI, AD 719 753,$3.00.

The report demonstrates the applicabilityof classical statistical techniques to problemsinvolving compression and classification ofmultivariate data. The theoretical foundationsof two such techniques, intrinsic analysis anddiscriminant analysis, are treated in detail.Efficient digital computer implementation isdiscussed, including the combined applica-

tion of intrinsic and discriminant analysisand a new algorithm for computing approxi-mate intrinsic bases for very large problems.Experimental results are presented on theapplication of these techniques as featureextractors in a signal classification problem.Also included is a description of the inter-active graphics-oriented system softwarewhich has been developed to facilitate theapplication of these techniques.

9135A Man-Machine Approach Toward Solvingthe Traveling Salesman Problem, P. Krolakand W. Felts (Vanderbit U., Nashville) andG. Marble (Washington U., St. Louis);Commun. Ass. Comput. Mach., vol. 14, pp.327-334, May 1971.

The traveling salesman problem belongsto an important class of scheduling and rout-ing problems. It is also a subproblem in solv-ing others, such as the warehouse distribu-tion problem. It has been attacked by manymathematical methods with but meagersuccess. Only for special forms of the problemor for problems with a moderate number ofpoints can it be solved exactly, even if verylarge amounts of computer time are used.Heuristic procedures have been proposed andtested with only slightly better results. Thispaper describes a computer aided heuristictechnique which uses only a modest amountof computer time in real time to solve large(100-200) point problems. This techniquetakes advantage of both the computer's andthe human's problem-solving abilities. Thecomputer is not asked to solve the problemin a brute-force way as in many of today'sheuristics, but it is asked to organize the datafor the human so that the human can solvethe problem easily. The technique used in thispaper seems to point to new directions in thefield of man-machine interaction and in thefield of artificial intelligence.

Mathematical Model for Analyzing theGrowth of Symbolic Logic-see 9055.

Model of the Interactive Multiterminal VideoGraphics Display System-see 9079.

Probability Models for Buffer Storage Alloca-tion Problems-see 9087.

Probabilistic Model of a MultiprogrammingSystem Under Demand Paging-see 9096.

Busy Period Analysis of a Time-Sharing Sys-tem Modeled as a Semi-Markov Process-see9097.

10) SCIENCE, ENGINEERING,AND MEDICINE

9136Feasibility of Minicomputer Implementationof a Time Division Multiplexer, M. Klein, A.Franco, and M. Epstein (Automated Infor-mation Systems, Inc., Edgewater); 99 pp.,Jan. 1971; CFSTI, AD 719 432, $3.00.

The study was undertaken to see if, in thelight of recent drastic price reductions andtechnology advancements, the use of a pro-

449k,

ABSTRACTS OF CURRENT COMPUTER LITERATURE

grammable general-purpose minicomputer asa versatile Time Division Multiplexer (TDM)now presents a more viable economic alterna-tive to the special purpose hardwired equip-ment commonly used for this purpose.Methods for software impelmentation of therequired TDM functions were explored, andpreliminary hardware and software conceptswere set forth. The study concluded that theconcept of implementing a minicomputerbased TDM using currently available ma-

chines is a feasible one. In addition, costadvantages aside, the flexibility inherent insuch an approach appears imminently de-sirable.

9137Animated Reconstruction of Telemetry (ART),R. G. DeBiase, B. E. Winn, M. J. Rade-macher, and R. P. Gross (Aerospace Corp.,El Segundo); Rep. TOR-0059(6452)-3, 40 pp.,Feb. 1971; CFSTI, AD 719 741, $3.00.

The techniques used in the animated re-construction of telemetry (ART) permit thenontechnical individual to evaluate the per-formance of complex technological processes.ART uses the modularized vehicle simulation(MVS) program to model the physical phe-nomena under study, thus ensuring con-formance to the laws of physics. Animatedsequences are then produced from thesemodels to visually portray the system inreference systems chosen by the user.

DESCRIPTOR-IN-CONTEXT INDEX

AAccess

Multiaccess Facilities Provided by a Satel-lite Computer 9098

Remote Multiaccess File Handling SystemOn-Line to CDC Computers 9101

Disk File Access Subroutine Package 9103Intelligence Systems with Direct Access to

the Data Base Through a Man-MachineDialogue 9108

Adaptive-see Patterns, Threshold, Training

Addition; Adders; AdditiveSerial Adders with Overflow Correction9072

Addresses; AddressingMinimizing the Sum of the Lengths ofAddress Codes Produced by Assemblersor Compilers 9084

Use of Buffer Memories to Reduce TimeSpent in Address Validation and Reloca-tion 9086

-see also Paging, StorageAlgebra; Algebraic-see Algebraic Equations, Automata,

Polynomials, Sequential MachinesAlgebraic Equations

Iterative Methods for Solving Systems ofAlgebraic Equations Using Decompos-able Operators 9119

Algorithms; AlgorithmicEffective Procedures for Speeding Up

Algorithms Using Recursion Theory 9056Parallel Thinning Algorithms for Digital

Pictures 9110Criteria for General Clustering Algorithms

9131Algorithms for:

Heuristic Minimization of AND-EXCLU-SIVE-OR Realization of Switching Func-tions 9058

Gate-Interconnection Minimization ofSwitching Networks Using NegativeGates 9061

State Minimization in Finite Automata9065

Inessential Errors in Sequential Machines9069

Review of Fault Diagnosis of Digital Sys-tems 9074

Heuristic Algorithm for Testing Asyn-chronous Sequential Logic Circuits 9075

Time-Series Analysis by Fourier Trans-formation 9076

Minimizing the Sum of the Lengths ofAddress Codes Produced by Assemblersor Compilers 9084

Calculation of Block Sizes for SequentiallyProcessed Magnetic Files 9100

Continuous Shading of Curved Surfaces9105

Optimal Detection of Curves in NoisyPictures Using a Multistage DecisionProcess 911 1

Establishing the Primality of Large Num-bers 9114

Discrete Nonlinear L1 Approximation 9116Fast Cyclic Convolution of Two VectorsOver a Commutative Ring 9127

Generation of Permutation Sequences 9128Multivariate Data Compression and Classi-

fication Using Interactive Techniques9134

AllocationProbability Models for Buffer Storage

Allocation Problems 9087-see also Paging

Analysis; AnalyticAnalysis of Store and Forward ComputerNetwork Performance and Costs 9077

-see also Mathematics, Numerical Analy-sis, Syntax

Approximation; Curve FittingDiscrete Nonlinear L1 Approximation 9116-see also Error, Extrapolation

ArithmeticScaling Machine Arithmetic and Inequali-

ties 9071-see also Addition, Division, Floating

Point, MultiplicationArraysComputing Capabilities of Real-Time Itera-

tive Arrays of Finite-State Machines 9067-see also Cells, Storage

Artificial Intelligence-see Heuristic, Inference, Patterns

Assemblers; AssemblyMinimizing the Sum of the Lengths ofAddress Codes Produced by Assemblersor Compilers 9084

Associative; Content-AddressedDesign of an Associative Memory UsingPush-Down Lists and LSI 9078

Automata; Turing MachinesState Minimization in Finite Automata

9065Information Processing and Transmission

in Cellular Automata 9066-see also Languages, Machines, Sequential

MachinesAutomated; Automatic; AutomationAutomatic Numerical Evaluation of Defi-

nite Integrals 9120-see also Machines, Programming

BBinary; Nonbinary

Binary Multiplication Scheme Based onSquaring 9073

-see also Addition, ArithmeticBoolean-see Sequential, Switching Functions

CCalculus-see Differential Equations

Cells; CellularInformation Processing and Transmission

in Cellular Automata 9066-see also Arrays, Associative

Circuits-see Gates, Integrated Circuits, Logic,

Networks, Sequential Machines, Switch-ing

ClassificationDefinition of a Divisive Monothetic Classi-

ficatory Program Applicable to MixedData 9130

Criteria for General Clustering Algorithms9131

Criteria for Choice Between NumericalClassifications 9132

Controversy Concerning the Criteria forClassification Strategies 9133

Multivariate Data Compression and Classi-fication Using Interactive Techniques9134

-see also Patterns

1429

IEEE TRANSACTIONS ON COMPUTERS, NOVEMBER 1971

Codes; Coding; Decoding; EncodingInstruction Code for the BRLESC II Com-

puter 9083Minimizing the Sum of the Lengths of

Address Codes Produced by Assemblersor Compilers 9084

Compilers; CompilingRecursion Induction Principle for Proving

Compiler Correctness 9057Minimizing the Sum of the Lengths ofAddress Codes Produced by Assemblersor Compilers 9084

Technique for Implementation of LabelVariables Which Traps ProgrammingErrors in Compilers 9085

Design of the Compiler for the Illiac IVComputer 9093

-see also Programming Languages, Trans-lation (Artificial Languages)

Computation; ComputingDeterministic Pushdown Store Machinesand Real-Time Computation 9067

Computing Capabilities ofReal-Time Itera-tive Arrays of Finite-State Machines 9067

Computation of Bounds for the Minimumand Maximum of a Polynomial in anInterval 9118

-see also RecursionComputer Applications

Computer-Assisted Documentation ofComputer Programs 9081

Generation of Halftones by Computer-Controlled Microfilm Recorder 9106

Feasibility of a Minicomputer Implementa-tion of a Time Division Multiplexer 9136

Animated Reconstruction of Telemetry9137

-see also Automata, Computer Systems,Computers, Documentation, Editing,Education, Mathematics, Patterns, Pro-grams for

Computer ScienceNumerical Analysis and Computer Science

in Retrospect 9052-see also Education

Computer SystemsCyclic-Queue Model of System Overhead inMultiprogrammed Computer Systems9096

-see also Computers, Digital Computers,On-Line, Operating Systems, Remote,Time-Sharing

Computer Utility; Computer NetworksMerit of Regional Computing Networks

for Educational Institutions 9054Analysis of Store and Forward ComputerNetwork Performance and Costs 9077

ComputersDesign of a Class of Fast Fourier Trans-form Computers 9076

Instruction Code for the BRLESC II Com-puter 9083

Interpreter Techniques for the GE-600Computer 9091

Design of the Compiler for the Iliac IVComputer 9093

Multiaccess Facilities Provided by aSatellite Computer 9098

Remote Multiaccess File Handling SystemOn-Line to CDC Computers 9101

-see also Automata, Computer Applica-tions, Computer Science, Computer Sys-tems, Graphics, Processes, SequentialMachines, Time-Sharing

ConversationalConversational Fortran Programming Sys-tem 9099

Intelligence Systems with Direct Access tothe Data Base Through a Man-MachineDialogue 9108

Correction; CorrectnessRecursion Induction Principle for Proving

Compiler Correctness 9057Serial Adders with Overflow Correction9072

-see also ErrorCorrelation

Time-Series Analysis by Fourier Trans-formation 9076

CostsAnalysis of Store and Forward CQmputerNetwork Performance and Costs 9077

D

DataDesign and Implementation of Program-ming Languages for Handling MultipleData Types 9090

Definition of a Divisive Monothetic Classi-ficatory Program Applicable to MixedData 9130

-see also Classification, Data Bases, DataManagement, Data Processing, Files,Information

Data BasesFeature Analysis of Generalized Data BaseManagement Systems 9104

Intelligence Systems with Direct Access tothe Data Base Through a Man-MachineDialogue 9108

Data ManagementFeature Analysis of Generalized Data BaseManagement Systems 9104

Data ProcessingSecurity Techniques for EDP of Multilevel

Classified Information 9053-see also Computer Systems, Digital Com-

puters, Education, ProcessingDecision Processes; Decidability

Relational Data File and the DecisionProblem for Classes of Proper Formulas9107

Optimal Detection of Curves in NoisyPictures Using a Multistage DecisionProcess 91 11

DecompositionIterative Methods for Solving Systems of

Algebraic Equations Using Decom-posable Operators 9119

DesignDesign of a Class of Fast Fourier Trans-form Computers 9076

Design of an Associative Memory UsingPush-Down Lists and LSI 9078

Role of Documentation in the Design andImplementation of Complex Program-ming Systems 9082

Design and Implementation of Program-ming Languages for Handling MultipleData Types 9090

Design of the Compiler for the Illiac IVComputer 9093

-see also RealizationDetection; Detectors

Optimal Detection of Curves in NoisyPictures Using a Multistage DecisionProcess 91 11

DiagnosisReview of Fault Diagnosis of Digital Sys-

tems 9074-see also Error, Tests

Differential Equations (Ordinary)Numerical Solution of Implicit First-OrderOrdinary Differential Equations withInitial Conditions 9121

Differential Equations (Partial)Optimum Extrapolated ADI Iterative

Difference Schemes for Solving Laplace'sEquation 9122

New Explicit Fourth- and Lower OrderRunge-Kutta Formulas with Applicationto Heat Transfer 9123

DigitalParallel Thinning Algorithms for Digital

Pictures 9110-see also Integrated Circuits, Switching

Digital Computers; Digital SystemsReview of Fault Diagnosis of Digital Sys-

tems 9074-see also Computer Systems, Computers,

ProcessingDisk Files; Disk StoresDisk File Access Subroutine Package 9103

DisplaysSystem for Viewing Stereoscopic Pairs on aCRT Display 9080

-see also Graphics, TerminalsDivision

Definition of a Divisive Monothetic Classi-ficatory Program Applicable to MixedData 9130

-see also MultiplicationDocumentation

Computer-Assisted Documentation ofComputer Programs 9081

Role of Documentation in the Design andImplementation of Complex Program-ming Systems 9082

Documentation and Editing of Algol 60Programs 9089

-see also Editing, Information

EEditing; EditorsDocumentation and Editing of Algol 60

Programs 9089Education

Merit of Regional Computing Networksfor Educational Institutions 9054

-see also Computer ScienceEquations

Class of Systems of Complex IntervalEquations Evaluable Iteratively 9115

-see also Algebraic Equations, IntegralEquations

EquivalencePCN Equivalence Class Invariants and

Information Quantities for SwitchingCircuits 9060

ErrorInessential Errors in Sequential Machines

9069Technique for Implementation of Label

Variables which Traps ProgrammingErrors in Compilers 9085

-see also Codes, CorrectionEvaluation

Criteria for Use in Selecting, Validating, orEvaluating Operating Systems 9094

Class of Systems of Complex IntervalEquations Evaluable Iteratively 9115

1430

ABSTRACTS OF CURRENT COMPUTER LITERATURE

Automatic Numerical Evaluation of Defi-nite Integrals 9120

-see also Computation, Performance,Tests

ExpressionsFormula Language for Heuristic Manipula-

tion of Mathematical Expressions 9113ExtrapolationOptimum Extrapolated ADI Iterative

Difference Schemes for Sovling Laplace'sEquation 9122

FFailures; Faults; Malfunctions-see Diagnosis

Files; FilingCalculation of Block Sizes for Sequentially

Processed Magnetic Files 9100Remote Multiaccess File Handling SystemOn-Line to CDC Computers 9101

Properties of the Scatter Storage Techniquewith Linear Probing 9102

Relational Data File and the DecisionProblem for Classes of Proper Formulas9107

-see also Data Bases, Disk FilesFloating Point

Connections Between Floating-Point andScaling Machine Arithmetic 9071

FourierDesign of a Class of Fast Fourier Trans-form Computers 9076

Functions-see Approximation, Recursion, Switching

Functions, Threshold

GGates

Gate-Interconnection Minimization ofSwitching Networks Using NegativeGates 9061

Generation; GeneratorsGeneration of Halftones by Computer-

Controlled Microfilm Recorder 9106Generation of Permutation Sequences 9128Systematic Generation of Ordered Se-

quences Using Recurrence Relations9129

-see also Displays, Noise, Numbers,Sequence

GeometryTopological Properties of Quantized Spaces

9125,9126Graphics; GraphicalModel of the Interactive MultiterminalVideo Graphics Display System 9079

Continuous Shading of Curved Surfaces9105

Generation of Halftones by Computer-Controlled Microfilm Recorder 9106

Parallel Thinning Algorithms for DigitalPictures 9110

Optimal Detection of Curves in NoisyPictures Using a Multistage DecisionProcess 9111

Networks of Constraints with Applicationto Picture Processing 9112

-see also Displays, Patterns

HHeuristic; Heuristics

Heuristic Minimization of AND-EXCLUSIVE-OR Realization of Switching Functions9058

Heuristic Algorithm for Testing Asyn-chronous Sequential Logic Circuits 9075

Formula Language for Heuristic Manip-ulation of Mathematical Expressions9113

Heuristic Man-Machine Approach toSolving the Traveling Salesman Problem9135

Images-see Graphics, Patterns

InequalitiesScaling Machine Arithmetic and Inequali-

ties 9071Inference; Induction

Inductive Method for Proofs About Re-cursively Defined Functions 9057

InformationSecurity Techniques for EDP of Multilevel

Classified Information 9053PCN Equivalence Class Invariants and

Information Quantities for SwitchingCircuits 9060

Information Processing and Transmissionin Cellular Automata 9066

-see also Codes, DataInput-Output

Generation of Halftones by Computer-Controlled Microfilm Recorder 9106

-see also Consoles, Disk Files, Displays,Man-Machine Communications, Ter-minals

InstructionsInstruction Code for the BRLESC II Com-

puter 9083Technique for Implementation of Label

Variables which Traps ProgrammingErrors in Compilers 9085

Integral EquationsEigenvalue Bounds for Integral Equations

9124IntegralsAutomatic Numerical Evaluation of Def-

inite Integrals 9120Integrated Circuits; Microelectronics

Design of an Associative Memory UsingPush-Down Lists and LSI 9078

-see also Arrays, CellsInteraction-see Graphics, Man-Machine Communi-

cationsInterconnections

Gate-Interconnection Minimization ofSwitching Networks Using NegativeGates 9061

-see also Integrated Circuits, NetworksInterpreters; Interpretive

Proofs About Interpreters for Program-ming Languages 9057

Interpreter Techniques for the GE-600Computer 9091

Iterative; IterationComputing Capabilities of Real-Time Itera-

tive Arrays of Finite-State Machines 9067Class of Systems of Complex Interval

Equations Evaluable Iteratively 9115Parametric Curve Fitting Using an IterativeMethod 9117

Iterative Methods for Solving Systems ofAlgebraic Equations Using Decompos-able Operators 9119

Optimum Extrapolated ADI Iterative

Difference Schemes for Solving Laplace'sEquation 9122

LLanguages; Linguistics; Grammars

Grammatical Characterization of One-WayNondeterministic Stack Languages 9064

-see also Programming Languages, SyntaxLogic; Logical

Mathematical Model for Analyzing theGrowth of Symbolic Logic 9055

-see also Arrays, Cells, Gates, Sequential,Switching Functions, Threshold

MMachines; Mechanization

Deterministic Push-Down Store Machinesand Real-Time Computation 9067

-see also Automata, Computers, Man-Machine Communications, SequentialMachines

Magnetic Disk-see Disk Files

Magnetic TapesCalculation of Block Sizes for Sequentially

Processed Magnetic Files 9100Man-Machine Communications (Interaction,

Systems)Multivariate Data Compression and Classi-

fication Using Interactive Techniques9134

Heuristic Man-Machine Approach toSolving the Traveling Salesman Problem9135

-see also Conversational, Displays,Graphics, Terminals

Mathematics; MathematicalFormula Language for Heuristic Manip-

ulation of Mathematical Expressions9113

Fast Cyclic Convolution of Two VectorsOver a Commutative Ring 9127

-see also Arithmetic, Differential Equa-tions, Fourier, Geometry, Logic, Models,Numerical Analysis, Optimization, Poly-nomials, Probability

Memory-see Storage

Minimal; Minimization; ExtremaHeuristic Minimization of AND-EXCLUSIVE-OR Realization of Switching Functions9058

Gate-Interconnection Minimization ofSwitching Networks Using NegativeGates 9061

State Minimization in Finite Automata9065

Minimizing the Sum of the Lengths ofAddress Codes Produced by Assemblersor Compilers 9084

Computation of Bounds for the Minimumand Maximum of, a Polynomial in anInterval 9118

-see also Optimal, Switching FunctionsModels; Modeling

Mathematical Model for Analyzing theGrowth of Symbolic Logic 9055

Model of the Interactive MultiterminalVideo Graphics Display System 9079

Probability Models for Buffer StorageAllocation Problems 9087

Cyclic-Queue Model of System Overihead inMultiprogrammed Computer Systems9096

1431

IEEE TRANSACTIONS ON COMPUTERS, NOVEMBER 1971

Busy Period Analysis of a Time-SharingSystem Modeled as a Semi-MarkovProcess 9097

Multiple-Access; MultiuserMultiaccess Facilities Provided by a

Satellite Computer 9098Remote Multiaccess File Handling System

On-Line to CDC Computers 9101-see also Multiprogramming, Time-

SharingMultiplexing

Feasibility of a Minicomputer Implementa-tion of a Time Division Multiplexer 9136

Multiplication; MultipliersBinary Multiplication Scheme Based on

Squaring 9073Multiprocessing-see Multiprogramming, Parallel, Time-

SharingMultiprogramming

Security Techniques in MultiprogrammingMultiprocessing Systems 9053

Cyclic-Queue Model of System Overhead inMultiprogrammed Computer Systems9096

-see also Time-Sharing

N

Networks; NetsMerit of Regional Computing Networks

for Educational Institutions 9054Realization of Switching Functions by

Cascaded Multithreshold Networks 9063Analysis of Store and Forward ComputerNetwork Performance and Costs 9077

Networks of Constraints with Applicationto Picture Processing 9112

-see also Arrays, Sequential Machines,Switching

NoiseOptimal Detection of Curves in Noisy

Pictures Using a Multistage DecisionProcess 9111

-see also StochasticNumbers; Numeric; Number Theory; Enumer-

ationEstablishing the Primality of Large Num-

bers 9114-see also Stochastic

Numerical AnalysisNumerical Analysis and Computer Science

in Retrospect 9052-see also Arithmetic, Differential Equa-

tions, Integral Equations

0

On-LineRemote Multiaccess File Handling System

On-Line to CDC Computers 9101-see also Real Time

Operating SystemsCriteria for Use in Selecting, Validating, or

Evaluating Operating Systems 9094Operations Research

Heuristic Man-Machine Approach toSolving the Traveling Salesman Problem9135

-see also QueuesOptimal; Optimization

Optimal Detection of Curves in NoisyPictures Using a Multistage DecisionProcess 9111

Optimum Extrapolated ADI IterativeDifference Schemes for Solving Laplace'sEquation 9122

-see also Minimal

pPages; Paging

Probabilistic Model of a Multiprogram-ming System Under Demand Paging 9096

Parallel; ParallelismDetermination of Program Suitability for

Parallel Processing 9095Parallel Thinning Algorithms for Digital

Pictures 9110Patterns

Trainable Classifier for Figural PatternRecognition 9109

PerformanceAnalysis of Store and Forward ComputerNetwork Performance and Costs 9077

-see also Computer Systems, CostsPolynomialsComputation of Bounds for the Minimumand Maximum of a Polynomial in anInterval 9118

Probability; ProbabiIisticProbability Models for Buffer Storage

Allocation Problems 9087Probabilistic Model of a Multiprogram-ming System Under Demand Paging 9096

Generation of Permutation Sequences 9128-see also Stochastic

Processes; Processing; ProcessorsCalculation of Block Sizes for Sequentially

Processed Magnetic Files 9100Parallel Thinning Algorithms for Digital

Pictures 9110Optimal Detection of Curves in Noisy

Pictures Using a Multistage DecisionProcess 9111

Networks of Constraints with Applicationto Picture Processing 9112

-see also Associative, Computers, DataProcessing, Information, Parallel

ProgrammingTechnique for Implementation of Label

Variables which Traps ProgrammingErrors in Compilers 9085

-see also Heuristic, MultiprogrammingProgramming Languages

Proofs About Interpreters for Program-ming Languages 9057

Facility for Partially Checking the Syntaxof a Line of an Algol Program 9088

Design and Implementation of Program-ming Languages for Handling MultipleData Types 9090

Intermediate Language for the PILERProgram Translation System 9092

Formula Language for Heuristic Manip-ulation of Mathematical Expressions9113

-see also Compilers, LanguagesProgramming SystemsRole of Documentation in the Design and

Implementation of Complex Program-ming Systems 9082

Conversational Fortran Programming Sys-tem 9099

Programs; RoutinesComputer-Assisted Documentation ofComputer Programs 9081

Facility for Partially Checking the Syntaxof a Line of an Algol Program 9088

Intermediate Language for the PILERProgram Translation System 9092

Determination of Program Suitability forParallel Processing 9095

Disk File Access Subroutine Package 9103-see also Paging

Programs for:Testing Asynchronous Sequential Circuits

9075Documentation and Editing of Algol 60Programs 9089

Determination of Program Suitability forParallel Processing 9095

Calculation of Block Sizes for SequentiallyProcessed Magnetic Files 9100

ProofInductive Method. for Proofs About Re-

cursively Defined Functions 9057

QQueues

Cyclic-Queue Model of System Overhead inMultiprogrammed Computer Systems9096

-see also Time-Sharing

RRandom-see Access, Noise, Numbers, Stochastic

Real TimeDeterministic Push-down Store Machinesand Real-Time Computation 9067

Computing Capabilities ofReal-Time Itera-tive Arrays of Fnite-State Machines 9067

-see also On-LineRealization; Implementation

Heuristic Minimization of AND-EXCLUSIVE-OR Realization of Switching Functions9058

Realization of Nonlinearly SeparableSwitching Functions 9059

Realization of Switching Functions byCascaded Multithreshold Networks 9063

Feedback in Homomorphic Realizations ofSequential Machines 9068

Technique for Implementation of LabelVariables which Traps ProgrammingErrors in Compilers 9085

Feasibility of a Minicomputer Implementa-tion of a Time Division Multiplexer 9136

-see also DesignRecognition-see Patterns

Recursion; Recursive; RecurrenceEffective Procedures for Speeding Up

Algorithms Using Recursion Theory9056

Inductive Method for Proofs About Re-cursively Defined Functions 9057

Systematic Generation of Ordered Se-quences Using Recurrence Relations9129

RemoteRemote Multiaccess File Handling System

On-Line to CDC Computers 9101-see also Terminals, Time-Sharing

SSecurity

Security Techniques for EDP of MultilevelClassified Information 9053

Sequences; SequencingGeneration of Permutation Sequences 9128Systematic Generation of Ordered Se-

1432

ABSTRACTS OF CURRENT COMPUTER LITERATURE

quences Using Recurrence Relations9129

-see also StochasticSequential

Calculation of Block Sizes for SequentiallyProcessed Magnetic Files 9100

-see also Sequential MachinesSequential Machines (Circuits, Logic, Net-

works)Feedback in Homomorphic Realizations of

Sequential Machines 9068Inessential Errors in Sequential Machines

9069State Assignment Procedure for Asyn-chronous Sequential Circuits 9070

Heuristic Algorithm for Testing Asyn-chronous Sequential Logic Circuits 9075

-see also Automata, MachinesSignals; Signaling

Design of a Class of Fast Fourier Trans-form Computers 9076

Simulation; Simulators-see Models

Software-see Operating Systems, Programming,Programming Systems, Programs

States-see Automata, Sequential Machines

Statistics; Statistical-see Correlation, Proabbility, Stochastic

StochasticMathematical Model for Analyzing theGrowth of Symbolic Logic 9055

Busy Period Analysis of a Time-SharingSystem Modeled as a Semi-MarkovProcess 9097

-see also Noise, ProbabilityStorage; Memory

Analysis of Store and Forward Computer

Network Performance and Costs 9077Use of Buffer Memories to Reduce Time

Spent in Address Validation and Reloca-tion 9086

Properties of the Scatter Storage Techniquewith Linear Probing 9102

-see also Allocation, Arrays, Associative,Disk Files, Files, Integrated Circuits,Magnetic Tapes, Paging

Switches; SwitchingPCN Equivalence Class Invariants and In-

formation Quantities for Switching Cir-cuits 9060

Gate-Interconnection Minimization ofSwitching Networks Using NegativeGates 9061

-see also Automata, Logic, Networks,Sequential, Switching Functions

Switching FunctionsHeuristic Minimization of AND-EXCLUSIVE-OR Realization of Switching Functions9058

Realization of Nonlinearly SeparableSwitching Functions 9059

Realization of Switching Functions byCascaded Multithreshold Networks 9063

-see also Automata, Logic, SequentialMachines, Threshold

Symbolic; SymbolsMathematical Model for Analyzing theGrowth of Symbolic Logic 9055

SyntaxFacility for Partially Checking the Syntax of

a Line of an Algol Program 9088-see also Languages

SystemsModel of the Interactive MultiterminalVideo Graphics Display System 9079

System for Viewing Stereoscopic Pairs on aCRT Display 9080

-see also Computer Systems, Displays,Information, Man-Machine Communi-cations, Multiprogramming, On-Line,Operating Systems, Programming Sys-tems, Time-Sharing

TTerminalsModel of the Interactive MultiterminalVideo Graphics Display System 9079

-see also Display, Input-Output, Man-Machine Communications

TestsHeuristic Algorithm for Testing Asyn-

chronous Sequential Logic Circuits 9075-see also Diagnosis, Evaluation

ThresholdRealization of Nonlinearly Separable

Switching Functions 9059Chow Parameters in Threshold Logic 9062Realization of Switching Functions by

Cascaded Multithreshold Networks 9063Time-SharingBusy Period Analysis of a Time-Sharing

System Modeled as a Semi-MarkovProcess 9097

-see also Multiple-Access, Multiprogram-ming, Remote

TrainingTrainable Classifier for Figural Pattern

Recognition 9109-see also Education

Translation; Translators (Artificial Languages)Intermediate Language for the PILERProgram Translation System 9092

-see also Compilers, Interpreters

1433

IEEE TRANSACnONS ON COMPUTERS, NOVEMBER 1971

IDENTIFIER INDEX

AAbelian Groups 9125,9126ACE Computer 9052ADI Method 9122Algol 60 Programs 9089Algol Syntax Checking 9088AND-EXCLUSIVE-oR Realization 9058Animation ofTelemetry 9137Asynchronous Sequential Circuits 9070, 9075Atlas Computer 9098

BBase-Limit Registers 9086Block Sizes 9100Blocking 9087Bounds 9118BRLESCII Instruction Code 9083Buffer Memories 9086, 9087Busy Period Analysis 9097

CCascaded Adders 9072Cascaded Multithreshold Networks 9063CDC 6000 Series Computers 9101Central Processor Utilization 9097CEP Functions 9059Channel Utilization 9096Checking Automata 9064Chow Parameters 9062Clustering Algorithms 9131Cobol Usage 9104COM 9106Commutative Rings 9127Compatible Sets 9061Complement Arithmetic 9071Complementary Even Parity Functions 9059Complemented Literals 9058Compression ofData 9134Connectivity 9126Contour Following 9109Convolution 9076Convolution of Vectors 9127Cooley-Tukey Algorithm 9076Coons Patches 9105Curve Detection 9111Curve Fitting 9117Curved Surface Shading 9105CW Networks 9063Cyclic Convolution 9127

DD-Algorithm 9075Definite Integrals 9120Demand Paging 9096Discriminant Analysis 9134Disk Latency 9093Distance Criterion 9109

EEigenvalue Bounds 9124Epidemic Model 9055Eucidean Transformations 9109

FFast Fourier Transform 9076Feature Analysis 9104Feedback Indegree 9068FIFO Lists 9078Figural Pattern Recognition 9109FOCUS System 9101Formula Languages 9113Fortran Compiler 9093Fortran (Conversational) 9099Fortran Parallel Path Recognizer 9095Fortran Subroutines 9103

GGE-600 Interpreter 9091

HHalftones 9105,9106Heat Transfer 9123Hidden Line Removal 9080,9105Homomorphic Realizations 9068

IIBM 1800 Application 9079Illiac IV Compiler 9093Implicit Differential Equations 9121Inessential Errors 9069Internal State Assignment 9070Interval Arithmetic 9118Interval Equations 9115Intrinsic Analysis 9134

LLL Approximation 9116Label Variables 9085Laplace-Stieltjes Transform 9097Laplace's Equation 9122Least-Squares Curve Fitting 9117Linear Probing 9102Linear Separability 9059LSI Memory 9078

MMarkov Chain Model 9055Microfilm Recording 9106MOS Integrated Circuits 9061Multiple Base-Limit Registers 9086Multiple Output Networks 9061Multithreshold Networks 9063

NNearest-Neighbor Recognition 9109Negative Gates 9061Nonerasing Stack Automata 9064Nonlinearly Separable Switching Functions

9059Nonuniversal Assignments 9070

0One-Way Stack Automata 9064Operators (Decomposable) 9119Order of Connectivity 9126Ordered Sequences 9129Overflow Correction 9072Overhead in Multiprogramming 9096

pParametric Curve Fitting 9117Partial Functions 9057Partition Pair Algebra 9069PCN Equivalence Classes 9060Permutations 9128,9129Picture Processing 9110, 9111, 9112PILER Translator 9091,9092Polymorphic Programming Language 9090Predictor-Corrector Methods 9121Proper Formulas 9107Push-Down Lists 9078

QQuantized Spaces 9125,9126Quarter-Square Multiplication 9073

RRelational Data File 9107Relocation 9086Runge-Kutta Formulas 9123

SSatellite Computers 9098Scaling Arithmetic 9071Scatter Storage 9102Semi-Markov Process 9097Serial Adders 9072Shading 9105Shared-Row Assignments 9070Skeletonization of Pictures 9110Slave Memories 9086SOAP Program 9089Special Purpose Computers 9076Spectrum Analysis 9076Speeding Up Algorithms 9056Squaring 9073Stack Automata 9064Stereo Viewing 9080Storage (Scatter) 9102Supercirculant Matrices 9127

TTaxonometric Strategies 9133Telemetry Animation 9137Thinning of Pictures 9110Three-Dimensional Viewing 9080Three-Threshold Function 9063Throughput 9077Time Division Multiplexer 9136Time-Series Analysis 9076Topology ofQuantized Spaces 9125,9126Trapping of Errors 9085Traveling Salesman Problem 9135Truncation Error 9123Turing Machines 9056

VValidation of Addresses 9086

xXerox Data Systems Sigma 2 9098

1434

ABSTRACrS OF CURRENT COMPUTER LITERATURE

AUTIHOR INDEX

AAhmed, R. 9059Alefeld, G. 9119Ali, M. 9059Allin, D. 9089Alway, G. G. 9114

BBaldwin, J. C. 9098Ball, D. 9101Banks, E. R. 9066Barbe, P.9091,9092Barron, D. W. 9099Beck, G. A. 9083Bell, T. E. 9079Bennetts, R. G. 9074Berg, R. 0. 9072Berkeley, E. C. 9081Bhat, U. N. 9097Bingham, H. W. 9053Blackall, P. M. 9101Blum, M. 9056

CChen, T. C. 9073Choudhury, A. K. 9063Clifford, H. T. 9132, 9133Coates, Jr., C. L. 9069Cole, S. N. 9067Corinthios, M. J. 9076

DDeBiase, R. G. 9137

DiPaola, R. A. 9107Dussel, R. 9118

EEpstein, M. 9136

FFehlberg, E. 9123Felts, W. 9135Fenichel, R. R. 9085Foerster, H. V. 9108Franco, A. 9136Frank, H. 9077

G

Gaver, Jr., D. P. 9087Gerard, V. 9101Ghosh, S. 9063Goffman, W. 9055Gonzalez, Jr., M. J. 9095Gouraud, H. 9105Gross, R. P. 9137Grossman, M. 9117

HHadden, E. W. 9088Hadjidimos, A. 9122Harlow, C. 9069Harrison, M. E. 9064Hillman, A. L. 9089Hopcroft, J. 9065

I

Ibaraki, T. 9061

KKing, W. K. 9078Kinney, L. L. 9072Klein, M. 9136Kral, J. 9102Krolak, P. 9135

LLance, G. N. 9130, 9132,

9133Lewin, D. W. 9074Lewis, P. A. W. 9087, 9096

MMacleod, G. R. 9101Maki, G. K. 9070Marble, G. 9135Marcer, P. J. 9101Marsal, D. 9124Matheson, W. S. 9060Mayer, 0. 9115McMurchie, T. D. 9103Millstein, R. E. 9093Mittwede, W. C. 9094Montanari, U. 9111, 9112Morris, Jr., J. H. 9057Munro, W. D. 9071Mylopoulos, J. P. 9125,9126

N

Nance, R. E. 9097Nielsen, N. R. 9054Nordstrom, A. W. 9058

0

Ord-Smith, R. J. 9128Ortony, A. 9080Osborne, M. R. 9116

p

Page, E. S. 9129Palandri, E. M. 9101Parnas, D. L. 9082Patterson, T. N. L. 9120Pavlidis, T. 9125, 9126Proll, L. G. 9088Putzolu, G. R. 9075

RRademacher, M. J. 9137Ramamoorthy, C. V. 9095Rao, V. V. 9058Richards, D. L. 9084Roper, R. B. 9134Rosenfeld, A. 9110Rossol, L. 9106Roth, J. P. 9075

SSchkolnick, M. 9064Schmitt, B. 9118

Scowen, R. S. 9089Shedler, G. S. 9096Shimell, M. 9089Sibson, R. 9131Standish, T. A. 9090Stefanelli, R. 9110Stein, M. L. 9071

T

Thomas, D. B. 9103Thomas, R. E. 9098Tracey, J. H. 9070

VVinea, A. 9109Vinea, V. 9109Vogel, E. 9113

wWaters, S. J. 9100Watson, G. A. 9116Wegbreit, E. L. 9090Wilkes, M. V. 9086Wilkinson, J. H. 9052Williams, W. T. 9130,9132,9133

Winder, R. 0. 9062Winn, B. E. 9137Wolfe, M. A. 9121

zZalcstein, Y. 9127Zeigler, B. P. 9068

1435