17 th European Symposium on Computer Aided Process Engineering – ESCAPE17 V. Plesu and P.S. Agachi (Editors) © 2007 Elsevier B.V. All rights reserved. 1 Generic Modelling and Simulation of Stock Levels in Supply Chains Edric Margono, Nouri Samsatli and Nilay Shah a a Centre for Process Systems Engineering, Department of Chemical Engineering, Imperial College London, Longon SW7 2AZ, UK, n.shah@imperial.ac.uk Abstract Stock levels of raw materials, intermediates and final products are a key performance measure of supply chains. Computer aided tools have helped in trying to understand the movement of stock levels and aid in making decisions that will improve these measures. This work aims to create a tool to help in the analysis and planning of existing systems via a robust planning mechanism and a simulator that incorporates stochastic elements. The tool is based on three main components: a data generator that generates, from historical data, demand forecasts scenarios; a robust planner that generates a plan from a selection of data scenarios; a simulator that puts the robust plan into action with the introduction of random events and a simple form of online scheduling (as a form of feedback control on the system) to examine how the system behaves under such conditions. Keywords: Chain, Robust Planning, Stochastic Elements, Stock Levels 1. Introduction Supply chain management is a field that has been attracting the interests of individuals working in the field of process engineering for two reasons, firstly, that it is an attempt to unify the optimization problem that is posed by a system from all levels, in terms of details, and in terms of field work. The second is that a lot of the optimization mechanisms and modeling and simulation techniques