Common operation scheduling with general processing times: A branch-and-cut algorithm to minimize the weighted number of tardy jobs

Common operation scheduling (COS) problems arise in real-world applications, such as industrial processes of material cutting or component dismantling. In COS, distinct jobs may share operations, and when an operation is done, it is done for all the jobs that share it. We here propose a 0-1 LP formulation with exponentially many inequalities to minimize the weighted number of tardy jobs. Separation of inequalities is in NP, provided that an ordinary min Lmax scheduling problem is in P. We develop a branch-and-cut algorithm for two cases: one machine with precedence relation; identical parallel machines with unit operation times. In these cases separation is the constrained maximization of a submodular set function. A previous method is modified to tackle the two cases, and compared to our algorithm. We report on tests conducted on both industrial and artificial instances. For single machine and general processing times the new method definitely outperforms the other, extending in this way the range of COS applications

Handling time-related demands in the home care nurse-to-patient assignment problem with the implementor-adversarial approach

The nurse-to-patient assignment is one of the main decisions in planning Home Care (HC) services under continuity of care. In the literature, this problem has been tackled with several approaches to take demand variability into account. However, patient’s demands at different time periods have been always assumed as independent, while they are highly correlated in practice. In this work, we propose a robust assignment model that includes the time-dependency of the demands in the HC nurse-to-patient assignment problem, based on the implementor-adversarial framework. Results from a relevant test case show the appropriateness of the approach and the capability to contain costs while respecting the continuity of care constraints

A QoS Concept for Packet Oriented S-UMTS Services

An approach by the IST FUTURE project to make packet based multimedia services feasible in a satellite based UMTS environment. Different QoS guaranteeing mechanisms are presented exploiting the terrestrial UMTS specification in order to achieve an integrated TS -UMTS. The focus is set on mechanisms for the access network, while the core network is only theoretically investigated in order to give an end-to-end QoS approach. For the access network, based on the UMTS specifications, algorithms for Connection Admission Control, Scheduling, Active Set Handling and Measurement Control have been proposed for an SUMTS environment