Spatial Network Generation Tool for Performance Analysis of Water Distribution Networks - Pattern Recognition for Reliability Assessment of Water Distribution Networks - page 82

Step 2 : The nodes for every link are retrieved by respecting their order ('NodeFrom' and
'NodeTo'). Furthermore, an adjacency list is prepared with connectivity code assigned for
each node ('ConCode', set as default to 0 and reset to 1 if the node link has been detected).

Step 3 : The array of nodes is compared with the array of links. The node found to exist in any
of the links from the array of links will change its connectivity code to 1. This kind of search
is sufficient to detect and eliminate the layouts, such as those shown in Figure 4.14, left and
middle.

Step 4 : With no disjoint nodes found in the previous step, the screening process continues
with the second stage, where the layouts with possible islands, as the one shown in Figure
4.14, right, are to be detected and eliminated. The connectivity code of all the nodes is again
set to 0 and new array created where all the nodes found to have connections in the repeated
search process will be stored.

Step 5 : The node that has been detected in the adjacency list will have its connectivity code
reset to 1 as well as all the other nodes found to be connected to it.

Step 6 : All the nodes detected in the previous step will be assigned to the array of found
nodes, if not existing there. The first of the adjacent nodes stored in this array is than taken
for the repetitive search in Step 5.

Steps 5 and 6 are repeated until all the nodes with 'ConCode' of 0 have been checked for
adjacency nodes. The program can also end its iteration when the array of found nodes has
been filled with all the existing nodes. In this case all the nodes have changed their
connectivity code to 1. Having any of the nodes with the connectivity code still at 0, after the
check has been done, will indicate island(s) in the network.

4.5.2 Assigning of Network Parameters

After the generation process has been completed, the pipe parameters have to be specified for
each layout in order to provide minimum input needed for EPANET to run hydraulic
simulation with sensible results. Three options available in NGT are shown in Table 4.12.

Table 4.12 Assigning of network parameters

Option 2:
Uniform (user defined
or default value)

Option 3:
Random values from
preselected range

Parameters Option 1

Length Node coordinates from *.inp file  

GA optimised diameter
(constraint: minimum pressure,
objective function: minimum cost)

Pipe
properties

Diameter  

Roughness -  

Node
properties

Elevation Same as in *.inp file - 

Demand Same as in *.inp file - 