Pair Kidney Exchange: Graph Visualisation

The aim of the application is to facilitate the presentation and comprehension of the data associated with Paired Kidney Exchanges.

The data is presented in the form of a directed graph with each vertex/node representing a donor/recipient pair and the edges representing compatibility between a donor and a recipient.

The data can then be passed to an external optimal matching API and the resulting optimal matching is presented on the graph through colouring nodes and edges

Function

Result

About

Explains the purpose of the application

Random Graph

Allows the user to create a random graph by defining the number of nodes and edge density. The density of the edges increments from 0.001 - 1.

Example Graph

A dropdown menu that presents options to create three different example graphs:

A small graph with less than 10 nodes
A large graph with more than 100 nodes
A graph that represents the ability to let recipients have more than one willing donor

Select File

Allows the user to open a specifically formatted XML or JSON file as a directed graph

Reset Graph

Allows the user to reset the graph by rebuilding from the currently open data pool and removing the optimal matching if previously run

Delete Graph

Allows the user to delete the current graph data. This function cannot be reversed.

Save Graph

Allows the user to save the currently open graph as an XML, JSON or image file

Layout Options

Allows the user to select from two different layout options which are updated when the Set button is pressed:

Barnes Hut: This layout options uses the barnes hut algorithm to present the nodes using the physics built into VisJS
Circle: This layout option presents the nodes in a circular layout

Matching Criteria

Allows the user to run an optimal matching request on the currently open graph. The API allows the user to select from two chain lengths and three operational types.

Option	Result
Chain Length	Determines the length of a chain that is allowed in an altruistic donor cycle
Operation: Optimal	Returns a set of exchanges with priortised constraints set as below: Number of effective pairwaise exchanges maximised Total number of transplants is maximised Number of 3 way exchanges minimised Numer of back-arcs in selected 3 way exchanges maximised Overall weight is maximised
Operation: Maxcard	Returns a set of exchanges with the below constraints priortised: Total number of transplants maximised Overall weight is maximised
Operation: Pairs	Returns a set of pairwise only exchanges with the below optimisations: Total number of transplants maximised Overall weight is maximised

Edit Menu

The edit menu on the graph canvas provides the user with the ability to manually plot or edit the graph. The options are below:

Option	Result
Add Node	Allows you to add a node and set the donor id, patient id, donor age and altruistic flag
Add Edge	Allows the user to create an edge between two nodes, by selecting a dragging from one node to the other, and set the edge score
Edit Node	Allows the user to edit a node, the node must first be selected and the edit button selected. Presents options to edit donor id, patient id, donor age and altruistic flag
Edit Edge	The ability to edit an edge is not present, the edge must be deleted and recreated using the add edge function.
Delete Selected	Allows user to delete the currently selected node or edge

Paired Kidney Exchange: Graph Visualisation

Layout options

Matching criteria

Matching Criteria

Exchange Data