Interactive Simulation Language Research Articles

Use of Colour to Describe System States in a Process Simulation Language

The paper describes an extension to a standard, block-structured, interactive simulation language in which colours are used to indicate the levels of variables in the simulated process. A coding system is used to classify the level of simulated process variables into three regions of safe, unsafe and dangerous operation, represented by green, yellow and red colours respectively. The enhanced simulation package facilitates controller development for industrial plant and avoids dangerous levels being overlooked in the simulation of prototype systems prior to their implementation on plant. The use of the enhanced facility is demonstrated by the simulation of the electrode drive system and controller for an electric arc furnace.

Generation of oscillatory behavior in the Laisk model of photosynthetic carbon assimilation

The metabolic pathways in photosynthesis are modelled as an interconnected series of chemical reactions representing the electron transfer system, the carbon reduction cycle and starch and sucrose synthesis according to the model of Laisk and Walker [Proc R Soc Lond 227, 281-302 (1986)]. The model is formulated as a set of non-linear differential equations using mass-action kinetics, and stimulated for transient behaviour using an interactive simulation language. The model responses to switched light demonstrate the existence of oscillatory behaviour, similar to that found experimentally in O2 evolution and chlorophyll fluorescence, and explain known transient behaviour. The model is also used to investigate the source of oscillatory behaviour in the phosphate translocator, and other transient phenomena associated with the cyclic electron transfer system.

Sonches — an interactive simulation language for design, validation and usage of ecological models

A simulator for ecological models is presented. Modelling language is shortly characterized. The main components of the simulation system are mentioned in connection with corresponding services. A full list of ecosystems modelled in SONCHES-calculus and running at present time is given.

ISIM - A simulation language for microprocessors

ISIM is a new simulation language for both 8- and 16-bit micro computers. It is derived from the interactive simulation language ISIS, which has been installed on a variety of minicomputers and mainframes over the past few years. ISIM can run on a small 8-bit microcomputer with the CP/M operating system, 48K bytes of memory and floppy discs. It also runs on the larger 16-bit com puters operating under CP/M 86 or MS-DOS, and on the IBM PC operating under PC-DOS. Its interactive graphics capability is best exploited using a graphics terminal or the microcomputer's integral graphics display (e.g., IBM PC Graphics Adapter). The language features interactive 'command' and 'program' modes and incorporates a simple editor and a file handling facility which is fully compatible with the operating system. ISIM provides a comprehensive, highly interactive, simulation environment which allows the user full control of the simulation. These features allow the simulation to be interrupted to enable the user to display or modify values of all user variables, change in tegration control variables, or perform post-mortem plots before proceeding with the execution of the run.

APL continuous system modelling program: an interactive simulation language

APL continuous system modelling program (APL-CSMP) is an APL based compiler and simulator system that enables the user to define and execute mathematical equations which may contain certain predefined mathematical functions and special operation blocks, supplied by APL-CSMP. Facilities allowing definition and changing of parametric data, end conditions, error bounds for computations, selection of the integration method, and control of the display of the results produced by the simulation run can also be included within the model. The source language has a syntax very similar to that of CSMP-III. Models are directly entered via the APL terminal in the form of mathematical equations and analysed by a compiler. The result of the compilation is a set of automatically generated APL functions incorporating an APL program equivalent to the model.

Interactive simulation on minicomputers : Part 1- ISIS , a CSSL language

Continuous System Simulation Languages (CSSLs) are used to program the simulation of dynamic systems that are described by differential equations. Mini computer-based languages are particularly attractive because they generally provide good man-machine interaction. This paper describes an interactive simulation language, ISIS, which provides many of the facilities hitherto restricted to large computers. ISIS is written in FORTRAN and can easily be imple mented on any computer that accepts FORTRAN IV pro grams (the original version runs on a PDP-8). ISIS is designed to offer the user high-level language facilities in the simplest possible form. Line-by- line syntax checking and the built-in editor allow fast interactive development of programs. The execu tion of a simulation can be interrupted by using special commands that allow the user to change the values of variables, modify or introduce OUTPUT and incremental PLOT statements, and produce 'post-mortem' graphs before continuing the simulation. With these and other interactive features, ISIS provides com prehensive facilities for the study of dynamic sys tems on modest minicomputer configurations.

Interactive simulation language for hybrid computers

The Interactive Simulation Language (ISL) is a power ful and easy-to-use software system for hybrid com puters using any of several different minicomputers. Its principal features are:

Simulation language implementation on minicomputers

Recent developments have shown the feasibility of implementing sophisticated simulation language facilities on even a modest minicomputer configuration. Unlike conventional simulation languages which, in the main, operate in a non-interactive batch mode, minicomputers generally allow the user to simulate in a highly interactive manner. This paper discusses three strategies used by the authors to implement different versions of an interactive simulation language on a minicomputer, and describes the means of achieving highly interactive simulation features. There are two fundamentally different approaches to implementing a simulation language. The first, a translator approach, makes use of existing software, for example editors, high-level language compilers, job control language features, and the language is built using these software foundation blocks. The second approach is to construct the facility independently of existing software and to provide a package which is quite independent of the computer's operating system. This second approach can be further subdivided into two branches, the compiler approach, in which the object code produced by a simulation language compilation is the machine code of the particular computer, and secondly the interpreter approach, where the object code is machine independent and is subsequently interpreted by code expressed in a high-level language. The various implementation strategies are described and the advantages and disadvantages of each approach are discussed in relation to three implementations of a simulation language for PDP8 computers.

Some improvement in prescribing oral contraceptives as predicted by a computer simulation

A simplified but representative model of the human menstrual cycle is reprogrammed in a new interactive simulation language, BIOMOD, and pulses representing various estrogen dominant oral contraceptives are added to the system. The system's response to these pulses gives a fair representation of the actual physiological response to oral contraceptives. New approaches are suggested for the generalized application of programable biological systems to problems of drug design and individualized drug prescription.

Interactive simulation language-8 (ISL-8)

ISL-8 is the first single precision, parallel interactive simulation language available for a minicomputer. This paper illustrates ISL-8 programming procedures and opera tional conveniences for solving a second-order differential equation and three nonlinear problems from science and engineering. The relationship to integration step size and computational accuracy is also shown. The article con cludes that ISL-8 as implemented on any of the 4K PDP-8 family of computers can accommodate up to 25 nonlinear differential equations at computational speeds 10 to 50 times faster than languages using floating-point methods. (8K systems can accommodate up to 100 nonlinear equa tions.)