FORTRAN control of graphics on the amiga microcomputer

The graphic capabilities of the Amiga microcomputer offer considerable potential for perceptual and cognitive research. These capabilities, however, are most easily accessed via the C programming language. Manipulating Amiga graphics hardware is considerably more difficult for the FORTRAN programmer. A package of FORTRAN 77 routines is described which has been designed to allow images to be easily processed and presented by means of calls from a FORTRAN experiment control program.     

FORTRAN control of graphics on the amiga microcomputer

The graphic capabilities of the Amiga microcomputer offer considerable potential for perceptual and cognitive research. These capabilities, however, are most easily accessed via the C programming language. Manipulating Amiga graphics hardware is considerably more difficult for the FORTRAN programmer. A package of FORTRAN 77 routines is described which has been designed to allow images to be easily processed and presented by means of calls from a FORTRAN experiment control program.     

A spectral-analysis tutorial with examples in FORTRAN

A procedure for performing spectral analysis using a digital computer is described. The relevant analysis parameters and their interaction are reviewed, and the underlying mathematical theory of the analysis is annotated with page references to a standard reference text. A computer program that implements the procedure is presented in a general form of FORTRAN. Examples of the spectra produced by a variety of input time histories are shown.     

Component analysis of ECG by computer

The present paper describes a set of interactive computer programs and methods (i.e., cardiac component analysis, CCA) that allow the collection, summation, and averaging of the time durations of the various ECG components. The programs are written in FORTRAN and run on a Texas Instruments minicomputer using an Intecolor 8001 terminal as the display device. The program’s features include analog-to-digital conversion, color display of individual heart-beats, operator interaction, and statistical summation with tabular output. Subroutines are well structured and easily transported to other machines. Although these programs may be used on-line, it has been more efficient to perform the analyses off-line, after a subject has completed the task. Various versions of the program have been used to analyze human, baboon, and dog ECGs in 2- to 30-sec epochs, at sample rates of 258 and 1,000 samples/sec. Preliminary results from an experiment of the effects of meditation and cognitive overload are discussed.     

A FORTRAN 77 program for sample-size determination in replication attempts when effect size is uncertain

A method of sample-size determination for use in attempts to replicate experiments is described. It is appropriate in situations where there is uncertainty about the magnitude of the effect under investigation. The procedure uses information supplied by the original experiment to establish a distribution of probable effect sizes. The sample size to be used in a replication study is that which provides an expected power of the desired amount over the distribution of probable effect sizes A FORTRAN 77 program is presented that permits rapid calculation of sample size in replication attempts employing comparisons of means, correlation coefficients, or proportions.     

A tachistoscopic software system for use in remote timesharing applications

A program is described that permits the use of an Imlac PDS-1 display computer, in conjunction with a host timeshare system, as a software-controlled tachistoscope. Alphanumeric and graphic message strings are received from the host computer over a telephone line, and are then displayed for specified periods of time in sequence. The display computer records the S’s responses and reaction time and reports this information back to the host computer for recording and analysis. The system is designed so that the burden of software development for the realization of a specific experimental plan is shifted to the large-capacity host machine, and it can utilize all of the features of standard FORTRAN as implemented on the host computer system.     

A simple LSI-11 system for real-time control,interevent time storage,and data analysis

A simple laboratory computer system based on a Digital Equipment Corporation LSI-11, floppy disk, DRV11 parallel input-output board, and the RT-11 operating system is described. Interface to experimental devices is provided through a lab-built relay driver and relay closure sensing interface. An extensive high-level software package provides an easy-to-use control language (e.g., stimuli can be controlled with a simple “TURN ON” or “TURN OFF” instruction) and easy-to-use FORTRAN subroutines for data exploration (e.g., “IFIND” searches a data file for a particular event). The control software automatically generates, codes, and stores a complete log of every input and output event and its time of occurrence in each of five simultaneously running experiments. This provides the capability to reanalyze data in light of hypotheses not available when the experiment was designed. The FORTRAN subroutine library for data exploration provides a conditional and iterative search facility to sift out events or sets of events from the data file for analysis. Standard FORTRAN statements perform arithmetic operations on the resulting data.     

Exact permutation probability values for weighted kappa

A permutation algorithm and associated FORTRAN program are provided for weighted kappa. Program EWK provides the weighted kappa test statistic and the exact one-sided upper-tail probability values.     

A vector graphic CRT display system

A vector graphic CRT display system for research in visual information processing is described. The vector graphic processor includes a 4K-byte display memory. The processor communicates with the controlling computer via a serial channel. The system is capable of exposure durations below 1 msec, and it allows on-line generation and modification of display files during an experiment. Brightness can be controlled separately for each vector of a picture. A graphic display editor in FORTRAN IV for interactive editing and debugging of display files has been developed.     

A computer system for automatically constructing stimulus material

A FORTRAN system for constructing various kinds of stimulus materials is described. A user enters the basic components of an experiment (stimulus items, presentation parameters, trial identifiers, etc.) as files, and uses the system to combine the basic files, automatically constructing the desired stimuli. The system contains file-manipulation functions for combining files (including factorial combination), functions for separating out parts of a file, and functions for randomizing files. The user can use the standard FORTRAN function-embedding and function-definition features to easily specify elaborate operations on the basic files to construct complex stimulus files.     

The Terpstra-Jonckheere test for ordered alternatives: randomized probability values

An algorithm and FORTRAN program are presented for the Terpstra-Jonckheere test statistic and associated probability value based on a randomization routine.     

Multidimensional scaling models for reaction times and same-different judgments

A method for joint analysis of reaction times and same-different judgments is discussed. A set of stimuli is assumed to have some parametric representation which uniquely defines dissimilarities between the stimuli. Those dissimilarities are then related to the observed reaction times and same-different judgments through a model of psychological processes. Three representation models of dissimilarities are considered, the Minkowski power distance model, the linear model, and Tversky's feature matching model. Maximum likelihood estimation procedures are developed and implemented in the form of a FORTRAN program. An example is given to illustrate the kind of analyses that can be performed by the proposed method.The work reported in this paper is supported by Grant A6394 to the first author from the Natural Sciences and Engineering Research Council of Canada. Portions of this study have been presented at the Psychometric Society meeting in Chapel Hill, N.C., in May, 1981. We thank Tony Marley, Jim Ramsay and anonymous reviewers for their helpful comments. MAXRT, a computer program which performs the computations described in this paper may be obtained by writing to the first author.     

Nonasymptotic significance tests for two measures of agreement.

The kappa agreement coefficient of Cohen from 1960 and Brennan and Prediger from 1981 are defined and compared. A FORTRAN program is described that computes Cohen's kappa and Brennan and Prediger's kappa and their associated probability values based on Monte Carlo resampling and the binomial distribution, respectively.     

A FORTRAN 77 program for a nonparametric item response model: The Mokken scale analysis

A nonparametric item response theory model—the Mokken scale analysis (a stochastic elaboration of the deterministic Guttman scale)—and a computer program that performs this analysis are described. Three procedures of scaling are distinguished: a search procedure, an evaluation of the whole set of items, and an extension of an existing scale. All procedures provide a coefficient of scalability for all items that meet the criteria of the Mokken model and an item coefficient of scalability for every item. Four different types of reliability coefficient are computed both for the entire set of items and for the scalable items. A test of robustness of the found scale can be performed to analyze whether the scale is invariant across different subgroups or samples. This robustness test serves as a goodness of fit test for the established scale. The program is written in FORTRAN 77. Two versions are available, an SPSS-X procedure program (which can be used with the SPSS-X mainframe package) and a stand-alone program suitable for both mainframe and microcomputers.     

Using a general analysis of variance algorithm for covariance designs

Procedures are described which enable researchers to implement balanced covariance designs of from one to four independent variables. Use is made of three subroutines from IBM’s Scientific Subroutine Package which implement a general decomposition algorithm for balanced designs. FORTRAN instructions, illustrating the main calling program, are given.     

Coding simultaneous experiments as independent FORTRAN subroutines

Simultaneous experiments can be coded as separate FORTRAN subroutines which pass requests for critical times and events to a coordinating subroutine named CHECK. These requests are stored in a “request table.” When all the experiments are temporally dormant, CHECK loops through the request table, checking each request. Whenever CHECK discovers that one of the requested times or events has occurred, it CALLs the subroutine of the appropriate experiment. In addition to supporting simultaneous experiments, this system permits a simpler style of programming experiments than that possible in unenhanced FORTRAN. This simplicity is largely due to the fact that the “loop and check” control structures are implemented in the CHECK subroutine and hence are transparent to the programmer.     

Micromanaging time: Measuring and controlling timing errors in computer-controlled experiments

Computer-controlled experiments present a number of potential sources of error in timing the presentation of events, including video refresh rate, keyboard scanning rate, and disk I/O times. A terminate-and-stay-resident routine implementing multiple millisecond-accuracy timers is presented. Interfaces permitting use of the timer with several higher level languages (C, FORTRAN , Pascal, and QuickBASIC) are described, as is a design for a two- to four-button response system using the computer’s printer port. A general strategy is described for using multiple timers to control and measure variation in critical experimental events. A C language program is provided to benchmark variation in the time required to perform common experimental tasks (screen refreshing, switching video pages, disk I/O, loop calculations), and results are summarized for several representative computers that use the IBM design.     

Statistical programs utilizing dynamic allocation of memory on the CDC 6400

Statistical routines written for general use often require large data storage arrays. A program using three n x n arrays, for instance, would require 30,000 words of memory for 100 variables. Usually the number of variables in any analysis is less than the maximum number of variables dimensioned in the program. This generally results in a number of unused data storage locations and a waste of computer resources. It would be advantageous to allocate storage for data arrays at execution time rather than at compile time, thereby minimizing storage requirements and turn around time for each program run. A series of multivariate analysis programs described by Cooley and Lohnes (1971) have been rewritten incorporating a subroutine, CORE, which dynamically allocates memory in blank common during execution according to parameters specified on the first cards preceding the data deck. In multiple problem runs, CORE is capable of either reducing or increasing field length, depending upon the number of variables included in the analysis. As an example, the CORREL program in the Cooley and Lohnes package requires a field length of 43000, words to execute on the CDC 6400 under SCOPE 3.3 without the CORE routine. As few as 16000, words are needed with the CORE routine.     

Use of a general analysis of variance program in missing data situations

Procedures are described which enable researchers to easily modify a general N-way analysis of variance program so that it can be used in unequal N cases. Advantages in terms of range of application, storage requirements, and accuracy are presented. FORTRAN instructions illustrating the general approach are given.