Modeling And Solution For Space Logistics Scheduling Of Slab Incoming Problem In Slab Yard

As an intermediate buffer unit between steelmaking-continuous casting and hot-rolling production,slab yard is used to adjust the production capacity of steelmaking continuous-casting and hot-rolling,to provide materials for the hot-rolling.The logistics process of slab yard includes slab incoming,shuffling and discharge.Reasonable logistics scheduling can effectively reduce operation time and preparation time of the implementation for hot-rolling plan and ensure the continuity of hot-rolled production.Slab incoming is the first step in slab yard logistics,which consider the orders,specification of storage slabs and corresponding security constraints of stack to determine the incoming of the storage slabs.Reasonable allocation of storage slab position,can improve the degree of regularity and logistics efficiency of slab incoming,and help to reduce the shuffling.Therefore,it is very important to study the modeling and solution techniques for space logistics scheduling of slab incoming problem,which could improve the logistics efficiency of slab yard.The main work of this thesis includes:(1)For the logistics process of slab incoming,considering slab stacking constraint and minimizing the crane moving distance,empty stack cost and the regularity in same stack,this thesis establishes mathematical model which determines the incoming of the storage slabs.This thesis uses CPLEX software to solve the model based on actual data and random data and achieve the optimal solution for the small-scale instances,verifying the correctness and effectiveness of the model.(2)This thesis proposes DE approach which is enhanced by a novel improving strategy,which can select the parameter and mutation strategy adaptively,to solve the space logistics scheduling of slab incoming problem.This thesis uses random,the solution of heuristic algorithm and local search algorithm to generate the initial population,which keeps population diversity.Considering the limitation of differential evolution algorithm for the unicity of mutagenic and crossover factors and mutation strategy,this thesis proposes an improving strategy to figure it out.Meanwhile,this thesis uses standard function to test the novel mutation strategy.Comparing the improved differential evolution algorithm with the artificial result on both the actual data from an iron and steel enterprises slab yard and random-generated simulating data,the fitness is improved by 30%.Comparing the basic differential evolution algorithm with the improved differential evolution algorithm,the convergence time is shortened in half.(3)According to the established mathematical model and the proposed differential evolution algorithm,this thesis develops the slab stack decision support system,which contains the downloaded data,parameter setting,recommended incoming,manual adjustment,the evaluation of results and upload results functions.Meanwhile,this system could implement the function of human-computer interaction,which could adjust the optimization results give the assessment of this operation.