Sigrid Knust

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A branch and bound algorithm is presented for the resource-constrained project scheduling problem (RCPSP). Given are n activities which have to be processed without preemptions. During the processing period of an activity constant amounts of renewable resources are needed where the available capacity of each resource type is limited. Furthermore,(More)
A new destructive lower bound for the resource-constrained project scheduling problem is presented. Given are n activities which have to be processed without preemptions. During the processing period of an activity constant amounts of renewable resources are needed where the available capacity of each resource type is limited. Furthermore, nish-start(More)
In a ow-shop problem with transportation times and a single robot n jobs consisting of m operations have to be processed in the same order on m machines. Additionally, transportation times are considered if a job changes from one machine to another. We assume that suucient buuer space exists between the machines and all transportations have to be done by a(More)
In a single-machine problem with time-lags a set of jobs has to be processed on a single machine in such a way that certain timing restrictions between the finishing and starting times of the jobs are satisfied and a given objective function is minimized. We consider the case of positive finish-start time-lags $l_{ij}$ which mean that between the finishing(More)
We present complexity results which have influence on the strength of list scheduling in a parallel machine environment where additionally precedence constraints and sequence-dependent setup times are given and the makespan has to be minimized. We show that contrary to various other scheduling problems, in this environment a set of dominant schedules cannot(More)
We consider a single-machine scheduling problem which arises as a subproblem in a job-shop environment where the jobs have to be transported between the machines by a single transport robot. The robot scheduling problem may be regarded as a generalization of the traveling salesman problem with time windows, where additionally generalized precedence(More)
We consider a generalised job-shop problem where the jobs additionally have to be transported between the machines by a single robot. Besides the transportation times for the jobs, empty moving times for the robot are taken into account. The objective is to determine a schedule with minimal makespan. We present local search algorithms for this problem where(More)