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Summary

The Bayesian Network adaptor (BNA) sets up a Bayesian network based decision support system (DSS) for coastal hazards and impacts in hotspot areas, according to the framework developed in task 3.3 of the RISC-Kit project (www.risckit.eu). 

The BN adaptor is an executable that uses

  1. .nc files of storm simulations
  2. .txt files indicating receptor locations 
  3. .json files specifying the structure of the BN
  4. a .json file specifying the vulnerability relationships for the hotspot area

to create

  1. a .dsl file that can be opened with the Bayesian network software GeNIe (www.dslpitt.org)

System Requirements

The BNA has been developed in c++. 

Windows

Currently the BNA for windows consists of an executable and a number of dll's. Moreover, it depends on

Linux (tba)

Linux users have to compile the source code. 

Configuration

Directory Structure

The BNA works with relative paths to read and write data. Initially, users have to create (manually) a directory Risckit/Modules/Genie/<case_study_name>/ which contains:

  • input/
  • model/
    • BNA.exe & related .dll's
  • output/
  • trainingData/
  • workDir/
    • info.json
    • BCnodes.json
    • Rnodes.json
    • Hnodes.json
    • Cnodes.json
    • Mnodes.json
    • <ID_of_receptor>.txt
    • vulnerabilies.json
    • shapefiles/
      • areas.shp & related GIS files

The folders input, output and trainingData remain empty. They are accessed by the BNA and the general adaptor (GA).

Overview on Data Process

The data process described in this section takes place after every single simulation with the model train. 

First, the GA writes the (near-shore) process model output (e.g. XBeach, Telemac) as

    1. hazardbc_<measure>_<bin>.nc
    2. hazard.nc

to Config/ModuleDataSetFiles.zip/BN_<hotspotname>/input. The first file should contain the max. value (scalar) of the relevant forcing variables, such as water level or significant wave height. <measure>_<bin> is an addition to the file name that only has to be used when the simulation includes a type I measure, i.e. measures affect the hazard pathway and require a different setup of the hydrodynamic model, such as beach nourishments, dikes etc. The second file contains the gridded maximum values of the relevant hazard variables, such as inundation depth, flow velocity or erosion. 

Subsequently, the GA calls the BNA.  

The BNA  

    1. copies the two files from input to trainingData/<yyyymmdd>_<measure>_<bin>
    2. reads all files in model and trainingData 
    3. creates output/<hotspotname>.dsl
    4. creates new directories output/webviewer/<scenario_X> for all combinations of hazard boundary conditions (forcing) that can be obtained from the BN including the folllowing files
      • <varname1>.json
      • <varname2>.json
      • ...
      • areas.shp & related GIS files

The user can open <hotspotname>.dne with a Bayesian network software. Note that input (and consequently trainingData) can be empty for the BNA to run. In this case <hotspotname>.dne represents the structure of the decision support system, but does not contain any quantitative information. 

Finally, the files in webviewer have to be copied/moved manually to a shared ftp (details will follow), where they can be picked up by the webviewer for display.

Input and Output Files

This section describes the formats of files that need to be placed in model and workDir by the user before the BNA is run and that are written to input and trainingData by the GA and its batch file. Note that the user develops his/her own GA and has to ensure that it writes files of the correct format to input and trainingData.

It also describes the files that are written by the BNA to output.

netCDF files

 

(to be added soon)

JSON files

JSON files can be created with any text editor. They are built on two structures: (1) a collection of name/value pairs and (2) an ordered list of values. Details can be found at http://json.org/. 

JSON files are read from workDir/ and written to output/ by the BNA. The following sections describe the files in workDir, which have to be manually created and placed there by the user, and contain examples. 

Info file

info.json contains four fields:

  • "name" specifies the filename of the resulting BN
  • "hazardbc_time" and "hazard_time" should be 1 and denote the time dimension of the netCDFs 
  • "hazardbc_stations" should be 1 and denotes the location of the boundary condition
  • "hazard_stations" specifies the number of model grid points
Structure files

The structure files contain the variable definitions (including the links between them) for the Bayesian network. Variables of different categories are defined in different files: 

Each variable definition contains five fields:

  • "ID" is used for cross-referencing. Note especially that in case of BC or H variables it corresponds to a variable name in the netCDFs and in case of R variables it points to a text file with name "ID"
  • "title" is the title of the variable as seen in the BN
  • "bins" is an array containing the bin values itself or the interval boundaries for each bin depending on the value in "nobins". The values can either be numeric or a string starting with a letter and without any spaces.
  • "nobins" is an integer defining the number of bins (or states) in the BN. If "nobins" equals the length of the "bins" array, each value in "bins" is a bin. If "nobins" is one smaller that the length of the "bins" array, the values in "bins" are taken to be the interval boundaries of each bin.
  • "parents" is an array of the "ID"s of parent variables or "None".

Above example files lead to this (INSERT LINK HERE) BN structure. 

Vulnerability file

(to be added soon)

Text files

(to be added soon)

Shape files

(to be added soon)

General Adaptor Run Example Configuration

(to be added soon)

 

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