A68SIM is a program system based on ALGOL 68, containing a set of procedures and operator definitions, which are designed to aid the writing of ALGOL-68-programs for discrete event simulation. A language with the power and flexibility of ALGOL 68 provides a variety of means for carrying out simulations, and A68SIM is just one of the possible approaches. A68SIM is a set of basic elements, and proceeding from these elements the user has a lot of opportunities in formulating and solving his simulation problem. This paper describes some features of A68SIM, originally developed by D.C.S. Shearn, Division of Economic Studies, University of Sheffield, U.K. and since some years implemented on our CD CYBER 172 and CYBER 76 at the Regional Computer Center at the University of Hannover, and compares it with SIMULA 67 and GASP IV, two other simulation “languages” at our site.
Transient oxygen and dioxide exchange processes within the upper skin can be simulated with the model of a microcirculatory unit. After a short description of the capillary loop model the corresponding mathematical nonlinear parabolic initial boundary value problem and the numerical procedure to calculate an approximation of the solution is presented. Some results of the calculation are described and discussed representing different oxygen supply situations of the upper skin.
This article describes a Decision Support System for modelling arid evaluating specific bankhall organizations. The DSS has been developed by the Rabobank Nederland for its organization consultants. The article pays attention to the structure of the DSS, the structure of the Simulation Model, the data organization and the Evaluation Reports. At the end some technical figures are given.
In contrast to many other industrial processes the design of control systems for air-conditioning plants cannot be based on fixed operating point parameters. For the design of control systems it is necessary to investigate the functional interrelations between operating point parameters and the dynamic behaviour. Due to the high costs of measuring the dynamic behaviour the investigations to be described are carried out by digital simulation. Based on simple mathematical models, which are available in the literature, the continuous-time transfer functions of an interesting configuration are transformed to a linear discrete-time description using the Z-Transform. For this step the structure of each device is taken into account. The results are a basis for discussion of the necessarity and the practicability of modern controlled systems in air-conditioning plants.
Cross-bridge behaviour within the sarcomeres of a muscle fibre is responsible for a great deal of muscular behaviour. Because cross-bridge properties cannot be measured directly, postulation of a basic structural concept for cross bridges is needed. To confirm this postulations, a mathematical model basing on the structural concept was derived. The results of; the model were similar to those of some experiments. For the explanation of further experiments, additions to the structural concept had to be made and the mathematical model had to be reformulated until all desired experiments could be explained by the model. Using this procedure an improved model was derived, which shows reasonable steady-states, transients, chemical energy turnover, stretch response and latency relaxations.
