In this note we give an easier proof of the known result that the car sequencing problem is NP-hard, and point out that it is NP-hard in the strong sense. We show that a previous claim of NP-completeness is incorrect , and instead we give a sufficient condition of membership of NP. We also provide a pseudo-polynomial algorithm for a special case.
The hybrid or flexible flowshop problem is a generalization of the flow-shop in such a way that every job can be processed by one among several machines on each machine stage. In recent years a number of effective exact methods have been developed. A major reason for this progress is the development of new job and machine based lower bounds as well as the… (More)
The usual assessment of general mental ability (or intelligence) is based on performance attained in reasoning and problem-solving tasks. Differences in general mental ability have been associated with event-related neural activity patterns of the wakeful working brain or physical, chemical and electrical brain features measured during wakeful resting… (More)
In this note we provide new complexity and al-gorithmic results for scheduling inventory releasing jobs, a new class of single machine scheduling problems proposed recently by Boysen et al. We focus on tardiness related criteria , while known results are concerned with inventory levels between fixed delivery points. Our interest is motivated by the fact… (More)