Four practical examples of simulation

Recent posts on this blog have been very theoretical: so here are four good examples of simulation as a useful tool, accepted as part of everyday life: in chemical spill tracking, traffic flow modelling, surgical anaesthesia, and waste water flow. None of these seem at all remarkable to us nowadays; all of them enhance life, or make it safer.

Im conscious that the last few posts on this blog have been asking some fundamental questions about simulation. To bring myself down to earth, here are four recent items that show simulation at its best, providing useful tools for humanity.

Last week in Brussels I saw a demonstration of Chemmap. This package plots the dispersion of vapour clouds from chemicals spilled into water. It crunches a large set of numbers: the physical properties of the chemical (how much dissolves, how much evaporates at given air and water temperatures), the water currents as far as they are known, wind strength and direction, and so on. Then it produces a moving map of the plume of vapour over time, showing density. In the hands of emergency responders, this can help to optimise their response. It is never going to be 100% accurate (it doesnt for instance take into account the nature of the ground the vapour is crossing – open fields or thickly wooded? – nor does it precisely model local mini currents of wind or water.) But it does give a good general indication – eg of which areas need to be evacuated if the spill is poisonous, how long before the cloud reaches them, and so on.

The Scotsman reported a programme model to help visualise traffic flow and to allow traffic planners to experiment with and optimise road and traffic signal combinations. The Vissim programme is written by Halcrows. A Scottish Executive report discusses several traffic simulation models “currently in use in the UK”. These include models (which “enable individual or groups of junctions to be modelled….”) such as AIMSUN, Dracula, Paramics, REVS, SISTM, VISSIM, as well as “software for modelling single junctions” such as LINSIG, OSCADY, TRANSYT, ARCADY, RODEL, and PICADY.

A study in Anaesthesia and Analgesia reports that participating anaesthetists omitted to check a median of 13 of 40 items when providing general anaesthesia for Cesarean delivery. (Items included “optimizing the patient’s head position”). The study suggests that a checklist similar to those used by pilots would increase patient safety. The anaesthetists taking part in the study worked entirely on “a high-fidelity anaesthesia simulator”.

MWH Soft has announced a new urban drainage systems modeling package that claims to help in both the design and day to day opartion of drainage systems. Incidentally there is a web site devoted entirely to, and named, Water Simulation Packages. Its reference to the MWH soft package is here.

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