UCSD Pascal Research Articles

CAI TOOLKIT

CAI TOOLKIT was developed to provide computer assisted instruction capabilities to those teachers without a technical background. Commands for the UCSD Pascal system are given in English, thus simplifying learning the system. It consists of six Tools: AUTHOR, CHED (Character Set Editor), SHPED (Shape Editor), LPRINT, UTIL, and LEARN. In beta sites with five instructors, it was found the system works well with languages as diverse as Chinese and Arabic, with storage capabilities for building up extensive character fonts.

Optimization of kinetic parameters for thermal degradation of kerogen: A Pascal program

Kinetic parameters for the thermal degradation of kerogens are derived both from isothermal and nonisothermal heating experiments and from field observations, and the data used in computer-aided basin modeling to simulate the maturation of source rocks and the timing of hydrocarbon generation and expulsion. A Pascal program for determination of kinetic parameters is presented, together with a simplified application. Thermal degradation of kerogen is modeled as a set of parallel, independent, irreversible first-order chemical reactions. The parameters for optimization are the fractional contributions of the parallel reactions, each characterized by a discrete activation energy level, and a single, global preexponential frequency (Arrhenius) factor. For a given frequency factor, determination of the reaction proportions reduces to least-squares regression analysis of an overdetermined set of linear equations, subject to nonnegativity and closure (sum to unity) constraints, solved using an active set method. The error function (mean-squared residual) then is a nonlinear function of the frequency factor and is minimized by one-dimensional interval reduction and line-searching techniques (minimum bracketing, golden section search, and inverse quadratic interpolation). The modular program operates in a UCSD Pascal P-system environment on a 640K IBM-compatible PC. Several sets of data may be combined, including simultaneous optimization of reaction rate and cumulative evolution (or transformation ratio) data. The number of parallel reactions, distribution of activation energies, and initial estimate for the frequency factor may all be changed. The program includes a procedure for fitting data to a single, first-order reaction, requiring optimization of one activation energy and the frequency factor. A mean-squared residual objective function is minimized using a multidimensional direction set method.

Computer‐Aided quantification of AES and XPS spectra

AbstractThe uses of a computer‐accessed database of elemental information relevant to quantitative interpretation of Auger electron and x‐ray photoelectron spectra will be described. Such a database has been compiled containing data on some 70 elements for access via UCSD Pascal computer programs implemented on IBM‐compatible microcomputers, Basic information required for the calculation of AES and XPS matrix factors is present in the database and routines for easy updating and extending of the information present are available. Programs for rapid calculation of the matrix factors needed for accurate quantification have also been developed to run in tandem with these library files. The simple data correction procedures present in these programs provide the analyst with a rapid method for obtaining an estimate of surface composition. Use of programs of this type help to prevent error by relying on the computer‐accessed library files for elemental information, help to prevent duplication of effort, and are of use in introducing the new surface analyst to the theoretical background to quantification. Some simple examples of uses of the programs are given.

A physical database design evaluation system for CODASYL databases

An interactive design tool for designing CODASYL databases is described. The system is composed of three main modules: a user interface, a transaction analyzer, and a core module. The user interface allows a designer to enter interactively information concerning a database design which is to be evaluated. The transaction analyzer allows the designer to specify the processing requirements in terms of typical logical transactions to be executed against the database and translates these logical transaction into physical transaction which access and manipulate the physical databases. The core module is the implementation of a set of analytical models and cost formulas developed for the manipulation of indexed sequential and hash-based files and CODASYL sets. These models and formulas account for the situation in which occurrences of multiple record types are stored in the same area. Also presented are the results of a series of experiments in which key design parameters are varied. The system is implemented in UCSD Pascal running on IBM PCs.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A rational reconstruction of a bubble chamber simulation using the Alternate Reality Kit

Interactive simulations for use in teaching physics have become commonplace. At CAL 83 there was a report on the design and use of a bubble chamber simulation. This program was implemented in UCSD Pascal. Students successfully used this program to learn about the appearance of bubble chamber tracks, the conservation laws at work in particle interactions and the random nature of particle creation processes. We have recreated and extended this simulation using the Alternate Reality Kit (ARK), a project under development at the Xerox Palo Alto Research Center. Our aim was to better understand the constraints imposed on the design of simulation by the language or system in which the simulation is developed. ARK is a graphical animated environment implemented in the Smalltalk-80 language for creating interactive simulations. ARK incorporates some unique features chosen to make its physics simulations both powerful and convincing. By reconstructing a familiar and tested simulation in the ARK environment, which is intended to be used by instructional designers with limited programming experience, we hoped to test out ARK's limits. In this paper we describe the new simulation in ARK as a rational reconstruction of the Open University package “Tracks”. The simulation was successfully reconstructed in about thirty hours (compared with one person year for “Tracks”). From the point of view of the simulation builder, the programming style needed for ARK works well. The design process involves representing interaction rules as interactors. We found that the exploratory nature of the simulation was enhanced by ARK. We also found that the major decisions about the form of the simulation could be delayed till fairly late in the design process. The original simulation game format has been extended to make several other teaching points, to provide a “laboratory for poets” and to teach the meaning of crosssection. ARK has been shown to embody a style of object-oriented programming particularly well suited to the visual depiction of physical laws. We have also shown that starting from the external behaviour of a complex physics simulation it is possible to mimic it in ARK and provide users with the opportunity to answer the question “how would particles behave if the laws of nature were otherwise”.

The Robot Brothers: An environment for learning parallel programming oriented to computer education

Computer Education is conceived as a process aimed at developing high level intellectual skills (problem solving, communication, independent learning, etc.) by an increasing number of people. In many cases this conception has been implemented by transferring models and methodologies originally belonging to the curricula of computer science specialists to the field of computer education. The paper offers a contribution to this process by considering the educational value of parallel programming, a subject well known to the specialists and well developed from the theoretical standpoint. The underlying hypothesis is that parallel programming can influence the capability to cope with real problems by adding a new dimension (the parallelism) to the learners' mental representations, based on the observation that most actual systems, not only computer systems, usually consist of some or many parallel activities (processes) cooperating (and often interfering) more or less intentionally to reach a goal. Handling aspects of parallel programming such as time dependence, interference, deadlock, and synchronization can be made approachable and even pleasant by means of a suitable learning environment. The environment developed, the Robot Brothers, consists of two or more Karel-like robots whose operations may be programmed by writing a concurrent program in Pascal. To make this possible a set of robot control primitives have been embedded in the language. The environment has been implemented in UCSD Pascal and uses the semaphore as the only synchronization device. Problems of increasing complexity introducing the various aspects of parallel programming are discussed and the behaviour of the environment is described in some detail. Possible developments include the introduction of more structured synchronization tools (monitors, path expressions) and an approach to concurrent programming based upon message exchange among processes.

Microcomputer System Design in the UCSD Pascal Programming Environment

ABSTRACT The potential of UCSD Pascal as a programming language for data acquisition and analysis was investigated. Cyclic voltammetry and chronoamperometry were automated by interfacing a BAS CV-27 potentiostat to an Apple II+ microcomputer. With the UCSD Pascal programming language, a modular approach was taken to solve our system design problem. Thus, smaller programs and library UNITs were written that collectively tackled a relevant electro-analytical problem. Here we focus on a modular approach to system design by discussing software techniques and applying them to the analysis of polymer modified electrode experiments. Additional conclusions relate this approach to other microcomputers, programming languages, and system designs.

A microcomputer program for second-order simulation of EPR spectra

A program for second-order simulation of isotropic EPR spectra has been developed for a microcomputer Apple II Plus. The programming is done in UCSD Pascal language. A recursion algorithm is developed for nuclear spin I < 0.5. Some applications of second-order simulations are calculated and discussed.

Generic data structures in UCSD pascal

Generic data structures in UCSD pascal

A microcomputer system for simulation modelling

Microcomputers are now widely used for discrete-event simulation work in Operational Research. An inexpensive microcomputer system for simulation modelling is presented. Based on an Apple II, it allows the programmer to develop three-phase activity based interactive models in Ucsd Pascal. Use is made of disc emulation for the provision of simultaneously available pictorial displays and the extension of fast access on-line memory for the development of large simulations. Use of a microcomputer speeds development time and gives the user a transportable computer dedicated to the simulation. Pascal facilitates the development of readable portable simulations. The simulation of a conveyer belt system demonstrates the simplicity and flexibility of the pictorial display. A practical study in the Health Service (modelling the treatment of chronic renal failure) illustrates that the package may be used to simulate a real and complex system.

A network interface unit simulation using micro PASSIM

This paper describes how micro PASSIM, a GPSS based simulation system, was transported from the Apple II to the HP 9836. The problems associated with moving a large program form one UCSD Pascal system to another are discussed. Micro PASSIM was transported to the HP system so that an Ethernet to HPIB interface board could be modeled. The model is described and the results obtained from the simulation are discussed. A discussion of the advantages and disadvantages of using micro PASSIM rather than a standard language, such as GPSS, is also included.

Simulation of an Ethernet interface using micro PASSIM

Micro PASSIM, a GPSS-based simulation system, was transported from the Apple II to the HP 9836; this paper discusses the prob lems associated with moving a large program from one UCSD Pascal system to another. Micro PASSIM was transported to the HP system so that an Ethernet to HPIB interface board could be modeled. The model is described and the results obtained from the simulation are discussed. Discussion on the advantages and disadvantages of using micro PASSIM rather than a standard language, such as GPSS, is also included.

Materials requirement planning with a microcomputer

Materials requirement planning (MRP) has been implemented on equipment ranging from early EAM punchcard equipment to the largest mainframe computers. The availability of relatively capable microcomputers raises the possibility of MRP systems for small operations. A major obstacle is that the concepts underlying most MRP systems are such that both time and memory capability become critical. A system of three programs has been developed using a different computational concept. The “Gozinto” method is used for structuring bill of materials data, and matrix multiplication is used for data manipulation and report generation. The system is reasonably fast, and uses disc memory to alleviate memory constraints. Written in UCSD Pascal, it is usable in any microcomputer supporting that language that has two disc drives and a minimum of 56K of memory. The first program is the bill of materials processor, which receives bill of materials data input from the CRT and stores it on disc using any firm's part coding system. The bill of materials file is then reindexed to develop a triangular matrix. This matrix is then inverted to arrange the bill of materials data in “indented” form. The second “planning” program receives input from the CRT to develop a data base containing master schedule, inventory, order, lot size and other data. The matrix multiplication of the data base and the indented bill of materials is then done on a disc-to-disc basis, obviating the need for large working memory. This second program also provides for revision of the data base as the time periods progress. Results are printed by a third program that essentially despools the matrix products. Limited testing using data from a cooperating firm indicates usefulness with a minimal computer configuration. Extension to larger firms seems feasible with modest memory expansion.

An Apple II-based slide-projector laboratory

We describe the software and hardware of a laboratory running under UCSD Pascal on an Apple II computer. The system includes: two random-access projectors and two standard projectors, all equipped with tachistoscopic shutters; two filter wheels; a voice key; a tone generator; and eight response boxes. The laboratory can be used for any experiment in which visual stimuli are to be presented and in which precise display times, reaction times, and luminances are required. It is particularly well suited to picture-perception and picture-memory experiments.

Surgical audit using patient records on a microcomputer

The collection and manipulation of patient data from the earliest stage by microcomputer is a desirable goal as in this way valuable information is captured which can be used for the administration of hospital admissions and subsequent analysis of the data will provide the information required for surgical audit. We have implemented a system using a pair of Apple II microcomputers with specifically written software in UCSD PASCAL that has been used in the clinical environment with proven success.

UCSD Pascal on the VAX, portability and performance

AbstractBetween 1976 and 1980 the Pascal Project at UCSD produced a ‘nearly portable’ operating system based on Pascal. Under the auspices of a graduate student project at UCSD, the UCSD Pascal system was ported to run in the 32‐bit address environment of the VAX 11/780 under VMS and UNIXUNIX is a trademark of Bell Laboratories. VAX and VMS are trademarks of Digital Equipment Corporation. UCSD Pascal is a trademark of the Regents of the University of California. . This paper describes the implementation decisions and the portability and efficiency considerations that motivated the decisions. Improvements to portability and efficiency are discussed.

A propositional analyst’s assistant

A system (PAN) that is designed to assist both the inexperienced and the experienced user in performing propositional analysis is described. The system is implemented in UCSD Pascal on the Apple II and Apple He microcomputers.

Using word reading time in text processing research

A study that employed a moving-window task was designed to test the paradigm’s sensitivity to different levels of interclause integration. The program that controlled the task, implemented on a Terak 8510/a microcomputer in UCSD Pascal, is described. The results of the study indicate that word reading time is indicative of lower and “midlevel” types of integration, but not higher order domain knowledge considerations.

On the design of monitors with priority conditions

Hoare[1] introduced the monitor as a tool for structuring the design of concurrent systems such as operating systems. He roposed the use of "priority conditions" to facillitate certain types of scheduling. However in his proposal there are no provisions for allowing a "customer" of the monitor to inquire as to the status of a condition. Such inquiries as "What is the highest priority process waiting on condition X?" or "How many processes are waiting on condition X with highest priority?" are not supported in Hoare's design. This paper investigates the implementation of priority conditions for monitors under UCSD Pascal and proposes two such status queries which are both useful and efficient. It is shown that the implementation of Hoare's "alarmclock" monitor is made simpler and more efficient through the use of these queries.

Analysis of large nucleic acid dot matrices on small computers.

A UCSD Pascal program was developed which can analyze nucleic acid dot matrices of up to 9500 X 9500 in size on the Apple II computer. Although matrices of such size consume large amounts of computer memory, this program minimizes these problems by analyzing only small strips of the matrix at a time, and then transferring the results to a floppy disk or printer. Compression and memory efficient code further enhance the size of the matrix that can be analyzed. By generating an image of the dot matrix using software, and sending this image directly to an Epson dot matrix printer, a very detailed print out may be produced. The program has a number of user selectable options which allow a great deal of control over the analysis. The program contains no computer dependent code, and thus should work on all systems that can run UCSD Pascal.