Changing the values of Model parameters

edit

Hi I have the following in my model plugin shown below, I was wondering how can I change the parameters of the <reset_frequency> such that it takes inputs from a ROS node which has a slider bar in it.

 <plugin name="particle_shooter_plugin" filename="libparticle_shooter_plugin.so">
  <reset_frequency>90.0</reset_frequency>
  <x_axis_force>-10000.0</x_axis_force>
  <y_axis_force>0</y_axis_force>
  <z_axis_force>0.0</z_axis_force>

  <x_origin>1.0</x_origin>
  <y_origin>0.0</y_origin>
  <z_origin>0.5</z_origin>

  <random_range>1</random_range>

</plugin>