Research On Project Cost Optimization Under Combination Precedence Relations And Resource Calendars Constraints

Resource-constrained Project Scheduling Problem(RCPSP)is one of the core problems of project management.The essence of this problem is to study how to make full use of limited resources to shorten the construction period,reduce production costs,and improve economic benefits.It is especially important in today's increasingly scarce resources.Although scholars at home and abroad have conducted extensive research on RCPSP and related issues,there are still some limitations in the priority relationship constraints,priority relationship expressions and resource calendar constraints related to actual RCPSP issues.Therefore,it is necessary to continue in-depth research to improve the practical application value of RCPSP.Based on the traditional RCPSP problem,this thesis takes the lowest cost as the optimization goal,and proposes the cost optimization problem of engineering projects under the constraints of combination priority relationship and resource calendar constraints for the first time.Firstly,in view of the lack of prior research on RCPSP's lack of constraints on combined precedence relations,the concept of combined precedence relations(CPRs,Combined Precedence Relations)is proposed on the basis of generalized precedence relations(GPRs,Generalized Precedence Relations)to enrich the priority relation constraint types of RCPSP.In order to avoid problems such as network loops when the traditional network diagram represents the combination priority relationship,we improved and proposed a new network diagram on the basis of the traditional network diagram.Its core is to use nodes to uniformly express the activity and priority relationship,which can more accurately and efficiently express the combination priority relationship.Secondly,based on the classic RCPSP,with the goal of minimizing the cost of resource use,a mathematical model of the project cost optimization problem(RCPSP/CPRs-cal)under the constraints of combination priority relations and resource calendar constraints is proposed.Then,in order to solve the RCPSP/CPRs-cal problem model,the GA-NND solving algorithm is proposed.GA-NND uses a new network graph to encode the problem based on the genetic algorithm,which simplifies the encoding process and improves the efficiency of the algorithm.Finally,we designed simulation examples and conduct numerical experiments to verify that GA-NND can solve large-scale and complex RCPSP/CPRs-cal problems accurately and efficiently.The research on the cost optimization of engineering projects under the constraints of combination priority and resource calendar has certain research value in theory and practice.In terms of theory,the research has enriched the types of RCPSP constraints and proposed effective algorithms for solving them.In practice,the research makes the RCPSP problem more in line with the actual project scheduling situation,and is used to guide decision makers to make more accurate scheduling plans.