VSZ  > Actual Traffic Model > Traffic Model

The traffic model keeps track of the vessel positions and the actual states of the infrastructure components (fairway, drawbridges, locks) and calculates short term forecasts (between 24 and 48 hours). The calculated forecast is used as an advice for the bridge and lock operators who remain in charge for the final decisions.

RIS-operators can fix bridge and lock operations in time and advise the software to force ships to be grouped for operations. To that end, they make use of the planner module.

The figure below is the output of a simulation run.

• Time is on the vertical axis, distance on the horizontal axis.

• The red blocks on the vertical stacks correspond to timeslots where network components are unavailable.

• The red curves (actually successions of small rectangles) correspond to fairway components that have been allocated exclusively to a particular vessel. In most cases this is caused by a wide (big) vessel crossing a narrow fairway component.

• The green line is for the traffic schedule being constructed. The bifurcations correspond to backtracking in the recursive algorithms.

• The blocks on the horizontal axis are a measure of the available width on the fairway.

The figure below shows data created during the calculation of a particular traffic schedule (calculations performed while adding a traffic schedule to the actual traffic model). This kind of diagram is not for use by RIS-Operators but is used as an analysing tool (debugging aid) and shows what goes on during a computation run.

• Legend
  
  

  Kanaal	Channel
  hindernis	Obstruction : the network component is not available either because a drawbridge is closed, a large ship occupies the fairway, ...
  operatie	Lock operation going on
  v_poging	Calculated velocity (speed) during a trial (calculation using a set of paramaters)
  v_finaal	Calculated velocity (speed) used in the final solution
  t_poging	Calculated time function value during a trial
  t_finaal	Calculated time function value in the final solution

• Labels written vertically are location name labels.

• Time vs. distance curve (yellow-brown curve)

• time is on the vertical axis
• distance is on the horizontal axis
• the yellow-brown curve shows the solution being found. Bifurcations again correspond to recursive backtracking. Because the algorithms are quite intelligent when deriving new parameter values, the amount of backtracking is small.

• Velocity vs. distance curve (blue curve)

• velocity (ship speed relative to land) is on the vertical axis
• distance is on the horizontal axis
• the blue line shows the ship speed (average speed integrated over the length of a network component (typically 80[m])).