Research On Scheduling Optimization Of Time-window Constrained Lap Networks Based On Paradox Analysis

At present,the technical requirements of network planning process are more and more complex,and the requirements of process duration are more and more diversified.The time window constraint lapping network contains all network planning constraints,which is more suitable for the actual needs of Engineering projects,especially for the implementation of large-scale projects.On the basis of introducing the theory and algorithm of network planning and lapping network,this paper summarizes the concept of time-window constrained lapping network,that is,whether the duration of process or the lapping relationship can be the lapping network planning with the maximum,minimum or time-window constraints.It can be said that the time window constraint lapping network includes all the time constraints in the project.Time window constrained lapping network is more suitable for the construction needs of today's engineering projects,so that the actual construction process will not be out of the network plan because of uncontrollable factors,so that the network schedule plan is scrapped.Using the method mentioned in this paper can effectively avoid the network infeasibility or network planning paradox.With the in-depth study of time window constraint lapping network,it will further promote the development of project management and improve the level of project management.In time-window-constrained overlapping network,there will be the phenomenon that network planning is not feasible.This paper makes feasibility analysis of time-window-constrained overlapping network and adjustment principle of network graph when it is not feasible,and adjusts the impractical time-window-constrained overlapping network to make network planning feasible.The algorithm steps of time parameters suitable for time window constrained network are given to determine the duration and key routes of network planning.In addition,this paper also finds that there are paradoxes in time-window constrained lapping networks that are inconsistent with the traditional CPM theory,including the path-length paradox in key processes and the total time-difference paradox in non-key processes.The reasons for these paradoxes are analyzed,and different optimization methods for different types of paradoxes are proposed to optimize the planning cost of networks.Finally,taking the actual pipelining project as an example,the feasibility analysis and adjustment,calculation of time parameters,determination of construction period and key routes,paradox analysis and optimization of the time window constraint lapping network plan of the project are realized.