Research And Application On Multi-project Scheduling Problem Of Block Erection At The Dork

Assembly at the dork plays an important role in shipbuilding process. The plan ofthe assembly has great effect on building period and quality of the ship. Thearrangement for the time and sequence of block erecting is of great importance inmaking full use of the resources on the dork and shortening the cycle of berth schedule.With the expansion of berth scale, shipbuilding enterprise often faced with theconstruction of multiple projects. Competition in resource may cause conflict ofmultiple projects, which will affect the task starting date and even delay the shipdelivery. How to arrange the time and sequence of block erection of multiple projects,while minimizing the makespan of multiple projects and balancing the use of sharingresource, is the main problem to schedule multi-project assembly plan.The study choose multi-project scheduling problem of block erection at the dork asresearch object. The aim of the study is to arrange the time and sequence of blockerection of multiple projects and minimize the makespan of multiple projects under theprecedence and resource constraint. This study is mainly from the following aspects:Firstly, the paper analyzed block assembly on the dock, which is a theoretical basisfor multi-project’s block erection on the same dock. The characteristics of resourceconstraints and block erection facility in the shipyard were explained. Combined withthe Ship Work Breakdown Structure, the network of block erection process in shipyardwas constructed.Secondly, a conceptual model about multi-project scheduling problem of blockerection was proposed, according to the resource-constrained project scheduling theoryand the characteristics of multi-project scheduling problem of block erection in ashipyard. A mathematical model about multi-project scheduling problem with thepurpose of minimizing the occupancy period of the dork was established. The key issuesthat must be addressed when particle swarm algorithm being applied in multi-projectscheduling problem of block erection at the dork are the mapping of particles andblocks and the scheduling generation scheme of multi-project scheduling of the blockerection at the dork whose priority value based on the positions of the particles. Both ofthem were investigated.Thirdly, the scheduling toolbox of multi-project scheduling of block erection at thedork was achieved based on particle swarm optimization algorithm and the start timeand end time of the block erecting was determined by using the scheduling toolbox；anassembly network plan system was designed and developed based on the MVCarchitecture, the system is of great significance in making assembly network plan of multi-project in ship building enterprises, through the implementation of the system, theefficiency of planning is improved and the multi-project berth occupancy is shortened.Finally, the block erection process of four projects being built in the same dork wassimulated. It is showed that, an excellent result can be found after200times of iterationusing the scheduling toolbox.50examples being investigated, of which the workinghours makspan of four projects were between230and239, showed that it is feasiblethat the PSO algorithm can be applied to schedule multi-project scheduling problem ofblock erection at the dork.