An enhanced continuous-time formulation is presented for the short-term scheduling of multipurpose batch plants with intermediate due dates. The proposed formulation is based on the continuous-time formulation introduced by Ierapetritou and Floudas (Ind. Eng. Chem. Res. 1998, 37, 4341 and 4360) and incorporates and elaborates on several features that include (i) various storage policies (UIS, F...

K. DeVries et al. recently presented 14C dates from Iron Age Gordion.1 They claimed that those dates require a destruction date for the site during 827–803 BC (95%-confidence range), which is a century or more earlier than the dates previously proposed. Herein, their claim is examined. (DeVries et al. also claimed artefactual support for their earlier date. O. Muscarella, however, has argued th...

Given a single machine and a set of jobs with due dates, the classical NP-hard problem of scheduling to minimize total tardiness is a well-understood one. Lawler gave an FPTAS for it some twenty years ago. If the jobs have positive weights the problem of minimizing total weighted tardiness seems to be considerably more intricate. In this paper, we give some of the first approximation algorithms...

In this paper, an integrated machine scheduling withits due date setting problem has been considered. It is assumed that the machine is subject to some kind of random unavailability. Due dates should be set in an attractive and reliable manner, implying that they should be short and possible to be met. To this end, first, long due dates are penalized in the objective function. Then, for each cu...

We use logic-based Benders decomposition to minimize tardiness in single-facility scheduling problems with many jobs and long time horizons. Release dates and due dates are given. A mixed integer linear programming (MILP) based master problem allocates jobs to segments of the time horizon, and a constraint programming (CP) based subproblem schedules the jobs in each segment.

In this paper we study the single machine total tardiness problem. We first identify some optimality properties based on which a special case with a given number of distinct due dates is proved polynomially solvable. The results are then extended to the case with release dates. 2004 Published by Elsevier B.V.

Encouraging natural enemies by growing attractive plants is considered an effective method of pest control in organic farming. However, it is important to identify which flowers best attract beneficial insects. In this study, relative attractiveness of 16 species of flowering plants to adult hoverflies was assessed by conducting timed observations of feeding-visit frequencies. The experiments w...