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Introduction

Insight is eWater’s multiple-objective optimisation decision support framework. This framework allows for more efficient evaluation of planning options than the traditional manual trial and error approach that is often used. In other words, the main aim of Insight is to optimise decision rules for all scenarios. The optimisation tool enables a more thorough examination of potential planning scenarios and the resulting trade-offs between desired outcomes.

Insight allows you to define which parameters (called decision variables) must be considered in the optimisation framework. Decisions variables and can be thought of as management levers that can be pulled to affect the outcome. For example, you may be unsure of what the operating rules for a new desalination plant should be used to meet the objective of minimising cost, or what the optimal operating rules are for transferring water between storages to meet supply security objectives and minimising environmental impacts. By creating decision variables for these operating rules, the optimiser will try hundreds or thousands of different operating rules based on these decision variables and determine how the rules perform against a set of specified objectives.

 

Configuring Insight

Pre-requisites for installing Insight

  • Latest version of Source. This must be correctly installed prior to running Insight;
  • Microsoft .NET framework v4 (or higher); and
  • Microsoft C++ 2010 x86 redistributable package

The Insight interface

When you open Insight for the first time, you may be prompted to point Insight to the location of the Source command line tool (RiverSystem.CommandLine.exe), as shown in Figure 1. 

Click Browse to locate and load the appropriate folder. Click OK to close the window.

Figure 1. Source command line location

 

Figure 2 shows the user interface for Insight, allowing you to load projects and work with objectives and variables.

Figure 2. Insight user interface

 

Setting up an optimisation run

  • Firstly, create a model and save it in Source.

Note the following when creating a model in Source:

  • Each project must consist of one scenario only;
  • Use the Function manager to define global expressions in your Source model for both objectives and decision variables.
  • Open Insight and click Browse (as shown in Figure 1) to choose the directory containing the project(s);
  • Click Load to populate the left panel with all the objective functions that were created in the loaded projects;
  • For each of the panels on the right, use the appropriate button to add or remove objectives or variables from the main objectives list to the individual panel. For example, click on the Add objective » button to add an objective to the Objectives panel. Moreover, to move a discrete decision variable back to the main list of objective functions, click on the « Remove discrete decision variable button.
  • In the Objectives panel, the Multi-project Aggregation Method drop-down menu allows you to choose how you want to aggregate the individual time-step results. The Aggregate over full timeseries checkbox allows you to choose how to setup the objectives. If enabled, the objective needs to be set up so that all values of the global expression are used (via the selected statistical function) to give the objective value. If not, the last value of the global expression gives the objective value. You can also remove an objective from the Objectives panel by choosing it from the list and clicking . This will move the objective back to the main objectives list.
  • Choose the number of generations and the population size of each generation. These parameters define how many simulation runs are performed by the optimiser. The required values will depend on the complexity of the optimisation project. If the number of runs is too small, the optimiser will not be given sufficient time to search for the multi-objective optimal set of results.
  • Specify whether to run the optimisation on your local machine (enable the Run Source optimisation locally radio button), or across server endpoints (using the Run Source optimisation on endpoints radio button). Server endpoints allow you to run the optimisation across several machines simultaneously. If running Source optimisation on a local machine, set the number of cores to use with the Local server limit scroll button. The number of cores to use depends on the machine you will are using.
  • Save your project settings using File » Save Settings.
Note: The difference between Objectives and tracked variables are that the former are optimised, whereas the latter are not. Tracked variables are a set of secondary objectives that may affect decision-making, but do not get optimised.

The optimisation can now be run using the user interface or the command line.

Using the interface to run an optimisation

Once an optimisation run has been setup, click Run to start the optimisation. Depending on the number of objectives and variables configured, the 

 

Viewing optimisation results

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