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 FORTRAN subroutine for sound production on the Amiga microcomputer

This article describes a FORTRAN 77 subroutine which manipulates the audio hardware facilities on the Amiga microcomputer. The subroutine may be instructed to produce either tones or musical notes on any combination of four independent channels. Frequency, volume, and type of waveform are passed to the subroutine as parameters. Some limitations in relation to sound production on the Amiga are discussed.     

An experiment control system for the Amiga microcomputer

The Commodore Amiga microcomputer, with its powerful and versatile hardware features, is well-suited to many areas of behavioral research. The complexity of the hardware and software, however, creates considerable difficulties for the researcher who wishes to construct real-time experiment-control programs. The present article describes a coordinated package of routines that have been designed to support experiment-control programs written in FORTRAN 77. The package was constructed specifically for cognitive research on verbal processes, but is sufficiently flexible to be useful in a variety of other applications. The functions performed by the program include the construction of stimulus displays, response detection, and timing operations.     

Frequency synthesis with the Commodore Amiga for research on perception and memory of pitch

The potential of the Commodore Amiga as a digital synthesizer for research and demonstration in psychoacoustics and memory is discussed. Economy, ease of use, flexibility, portability, and accuracy outweigh disadvantages of narrow bandwidth, narrow dynamic range, and storage limitations for many applications encountered in pilot research and education. The Amiga also bears serious consideration for psychoacoustic studies requiring frequencies below 4000 Hz and modest signal-to-noise ratio, as exemplified by an implementation for research in absolute judgment, similarity scaling, and sequential pattern tracking.     

Amiga 1000 hardware timing and reaction-time key interfacing

A method of hardware reaction timing with millisecond accuracy, using one of the Amiga’s CIA 8520 chips, is described. The registers of this chip can be set to enable cascaded timing that functions independently of the CPU and, thereby, avoids the problems of software timing in a multitasking environment. In addition, the interfacing of a pair of reaction-time keys to one of the Amiga’s game controller connectors and a program for polling this port for keypresses are described.     

Software-based visual psychophysics using the Commodore Amiga with Deluxe Paint III

Often it is useful to produce visual displays that allow for pilot testing of experimental hypotheses, which let the experimenter examine effects reported by others, or which can be used for at least some serious experimentation (e.g., decrement in visual illusions with practice). The combination of the Amiga computer and Deluxe Paint III software is ideal for this purpose. The ease with which graphic displays can be produced, coupled with the new animation facility in the software, enables method-of-adjustment psychophysical experiments to be produced in a very short time. Worked examples are given, and the relative merits and shortcomings of the Amiga computer for these purposes are discussed.     

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.     

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.     

Visual stimuli on the Commodore Amiga: A tutorial

The Commodore Amiga home microcomputer, together withDeLuxePaint, a commercial software package, can generate many useful visual stimuli, including random-dot stereograms, apparent motion, texture edges, aftereffects from dimming and brightening, motion aftereffects, dynamic random noise, and drifting and counterphase gratings. Videotapes can readily be made of these displays. No programming experience is necessary.     

The exact null distribution for radial maze statistics: A FORTRAN 77 program

Performance in the radial-arm maze may be assessed by comparing the number of correct responses or, alternatively, the number of repetition errors with that expected if a subject were simply selecting a location at random on each choice. Previous attempts to estimate the null distribution of correct responses or repetition errors have re-lied on computer simulation. In the present approach, a direct analytic argument is used to derive exact expressions for the probability density functions of these random variables. Knowledge of the exact null distributions provides the researcher with enhanced analytic capabilities. For example, it supplies the means of constructing an exact test of significance to evaluate performance at the level of a single subject A FORTRAN 77 program is provided to compute the null distribution of correct responses and repetition errors as well as their respective expectations and variances. Application of the technique to other situations is described briefly.     

HDC: A subroutine library for image processing using Burt’s hierarchical discrete correlation

This paper describes a library of subroutines that efficiently implement Burt’s (1981) hierarchical discrete correlation (HDC). The subroutines are written in Professional FORTRAN for IBM PCs or compatibles. Subroutines are included for both even and odd forms of the HDC, as well as for the corresponding algorithms for pyramid processing. Odd width kernels of up to 7×7 pixels and even width kernels of up to 6×8 pixels can be programmed easily with these subroutines. Thus, this library contains the forms of HDC that are most widely used in image processing and visual modeling. I show the efficiency of this implementation by reporting the execution time of each subroutine for several image sizes. I also present a method that simulates rotation of the kernel in order to allow applying kernels without circular symmetry at the desired orientation.     

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.     

The Acceptability and the Tolerability of Societal Risks: A Capabilities-based Approach

In this paper, we present a Capabilities-based Approach to the acceptability and the tolerability of risks posed by natural and man-made hazards. We argue that judgments about the acceptability and/or tolerability of such risks should be based on an evaluation of the likely societal impact of potential hazards, defined in terms of the expected changes in the capabilities of individuals. Capabilities refer to the functionings, or valuable doings and beings, individuals are able to achieve given available personal, material, and social resources. The likely impact of a hazard on individuals' capabilities should, we argue, be compared against two separate thresholds. The first threshold specifies the minimum level of capabilities attainment that is acceptable in principle for individuals to have in the aftermath of a hazard over any period of time. This threshold captures the level that individuals' capabilities ideally should not fall below. A risk is acceptable if the probability that the attained capabilities will be less than the acceptable level is sufficiently small. In practice, it can be tolerable for some individuals to temporarily fall below the acceptable threshold, provided this situation of lower capabilities attainment is temporary, reversible, and the probability that capabilities will fall below a tolerability threshold is sufficiently small. This second, tolerable threshold delimits an absolute minimum level of capabilities attainment below which no individual in a society should ever fall, regardless of whether that level of capabilities attainment is temporary or reversible. In this paper, we describe and justify this Capabilities-based Approach to the acceptability and tolerability of risks. We argue that the proposed theoretical framework avoids the limitations in current approaches to acceptable risk. The proposed approach focuses the attention of risk analysts directly on what should be our primary concern when judging the acceptability and the tolerability of risks, namely, how risks impact the well-being of individuals in a society. Also, our Capabilities-based Approach offers a transparent, easily communicable way for determining the acceptability and the tolerability of risks.     

Top-down design for a system to control operant choice experiments

STATIONS, a FORTRAN program to control operant choice experiments, was developed based on the principles of top-down design and structured programming. As a consequence, the program consists of modules organized in a hierarchical fashion. Separate modules deal with different types of reinforcement schedules, such as variable ratio (VR) and variable interval (VI). These modules produce specific schedules with different parameters by using sequences of values read in at ran time and then randomly sampled. This form of organization permits modifications to be made via changes confined to one module without global repercussions. The clarity of structure that results from the application of top-down design and structured programming should enable future users to more easily adapt this package to suit their specific needs.     

A simple IBM I/O Selectric typewriter controller

A simple inexpensive IBM I/O Selectric typewriter controller is described. The board plugs into an RS-232 port and enables letter-quality output. Computers with editing capabilities can therefore be used as word processors for as little as $35, about 8 h of labor, and the cost of the typewriter. The controller is a firmware-governed microprocessor, and as a result, it is easily tailored for special applications. Hardware and software are discussed.     

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.     

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.     

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.     

NORMUL: A FORTRAN program for testing multivariate normality

NORMUL is a FORTRAN program that provides a test of whether data conform to a multivariate normal distribution. The method involves correlating Mahalanobis distances for observed data with expected chi-square percentile values. This obtained correlation is then tested for significance by empirically evaluating the probability of its belonging to a distribution generated from multivariate normal data.