Research Article

Emergency Vehicle Dispatching and Redistribution in Highway Network Based on Bilevel Programming

Algorithm 1

Bilevel shuffled frog leaping algorithm for emergency vehicle dispatching problem.
Input: The population size , the number of memeplexes , local search iterations It, global search iterations IT, the
maximum step size , the accident’s requirements , the potential incident’s requirements , the punishment
for accident requirements , the punishment for potential incident requirements , the time window , ,
the punishment for the time window constraints , , the travel time , .
Output: Process of optimization of , the optimal dispatching strategy.
Begin
  (0.0) Parameter initialization;
  (0.1) Initialize the position of frogs randomly;
  (0.2) For
     (1.0) Substitute into the second-level model, apply , and iterate with as guidance until the
      optimal solution to the second-level model is obtained;
     (1.1) Substitute into the first-level model, calculate of frog .
    End
  (0.3) For IT >
     (2.0) frogs are ranked in descending order of the value , and record position of the best frog ;
     (2.1) According to the formula (12), frogs are distributed into memeplexes, each of which contains frogs;
     (2.2) For
        For
         (3.0) Renew the position of the worst frog according to the formula (13) and (14);
         (3.1) If Step (3.0) fails to improve the value of the worst frog, then replace the
          in formula (13) with and renew the position of the worst frog;
         (3.2) .
        End
       End
     (2.3) Mix all the memeplexes;
     (2.4) .
    End
  (0.4) Output the optimal solution and the performance function value , and the algorithm stops running.
End