平行机上带有前瞻区间的不相容工件组在线排序问题

研究当不相容工件组的个数与机器数相等时,具有前瞻区间的单位工件平行机无界平行分批在线排序问题.工件按时在线到达, 目标是最小化 最大完工时间. 具有前瞻区间是指在时刻t, 在线算法能预见到时间区间(t,t+beta) 内到达的所有工件的信息.不可相容的工件组是指属于不同组的工件不能被安排在同一批中加工. betageq 1 时, 提供了一个最优的在线算法; 当0leq beta < 1时, 提供了一个竞争比为1+alpha 的最好可能的在线算法, 其中alpha是方程alpha^{2}+(1+beta) alpha+beta-1=0的一个正根.最后, 给出了当beta =0 时稠密算法竞争比的下界,并提供了达到该下界的最好可能的稠密算法.

On-line algorithms for incompatible job familieson parallel machines scheduling with lookahead

We consider the on-line scheduling of incompatible unit-length job families on unbounded parallel-batch machines with lookahead when the number ofjob families is equal to the number of machines. In this paper online means that jobs arrive over time. The objective is to minimize the makespan. In the lookahead model, at a time instant t , an on-line algorithm can foresee the information of all jobs arriving in the time segment (t,t+beta). By incompatible jobfamilies, we mean that jobs from different families cannot be assigned together in the same batch. When beta geq 1, we provide an optimal online algorithm; When 0leq beta < 1, we give a best possible online algorithm of competitive ratio 1+alpha, where alpha is the positive root of the equation alpha^{2}+(1+beta) alpha+beta-1=0. We also provide a new lower bound on the competitive ratio for dense-algorithms, and present a best possible dense-algorithm matching this lower bound.