Towards better understanding of forestry-wood chain simulation through visualization and interactivity

Sammanfattning: Simulation studies performed on the forestry-wood chain trend towards either complicated calculations on large data-sets, statistical exercises on endless production data, optimisations on specific sub domains, or a combination of the above. The studies are often presented through graphs showing how scalars such as value, profit, or yield fluctuate when parameters of the simulation model are tweaked. The simulation models are usually stringed together from a series of operations performed in various software packages, scripts, macros and purpose written code. Reusing code from past studies is common practise, either as part of the new program, or by simply running the data through an executable and parsing the results in the next operation. Since there is no framework built around the operations, changing the input data will often mean that you have to start again from the top, guiding the data through all the different steps manually. To make things worse; the simulation model, the experiment code, and the analysis code tend to be mixed together making validation and verification difficult. Keeping track of how each operation impacts the result is difficult, and understanding how different parameters interact with each other on a system-wide basis is hopeless. Despite already being complex, most studies omit important aspects of the system they are modelling. Processing time, stochastic behaviour, separation of experimental data from model data, and so on. At the same time, if the fidelity of the simulation models continue to increase, they will eventually become too unwieldy to comprehend. Despite this, simulation is one of the most important tools available when trying to improve the forestry-wood chain, and the results that have been produced through the use of simulation are awe-inspiring. With proper tools and methodology, the integrated simulation model of the forestry-wood chain is not far away. This document is an attempt at finding tools that help design understandable simulation models of the complex systems in the forestry-wood chain. The hypothesis is that visualisation and interactivity can give alternative feedback on simulation models, providing better foundations for decisions than scalar measures like profit or yield.