Designing a search heuristic for constraint programming that is reliable across problem domains has been an important research topic in recent years. This paper concentrates on one family of candidates: counting-based search. Such heuristics seek to make branching decisions that preserve most of the solutions by determining what proportion of solutions to each individual constraint agree with t...

1 In this paper we present our experience in solving Air Traffic Controller Shift Scheduling Problem. We give a formal definition of this optimization problem and introduce three encodings. The encodings make possible to formulate a very wide set of different scheduling requirements. The problem is solved by using SAT, MaxSAT, PB, SMT, CSP and ILP solvers. In combination with these solvers, thr...

AIM To describe a pilot project on self-scheduling (self-rostering) for hospital nurses and assess its potential values and difficulties in implementation. BACKGROUND Self-scheduling is one aspect of the effort to make the hospital nursing environment more accommodative of nurses' lives. It is part of the good employment practices that nurses want and that can help recruitment, retention and-...

preventive maintenance scheduling is to perform a series of tasks that prevents or minimizes production breakdowns and improves the reliability. mathematical models have been developed to solve the preventive maintenance scheduling problem. there are several limitations in the prior work in this area of research. craft combinations are assumed to be given. the craft combination problem concerns...

The ATMOSTSEQCARD constraint is the conjunction of a cardinality constraint on a sequence of n variables and of n− q + 1 constraints ATMOST u on each subsequence of size q. This constraint is useful in car-sequencing and crew-rostering problems. In [18], two algorithms designed for the AMONGSEQ constraint were adapted to this constraint with a O(2n) and O(n) worst case time complexity, respecti...

In this paper, we consider the Multi-skill Crew Rostering Problem. We propose a constraint programming approach based on constraint set variables. We prove that this approach yields an exponential factor improvement in the worst-case search space over the conventional constraint programming approach. To handle preferences, we follow a ''relax and enrich'' scheme of Schmidt. Using our approach, ...

Schedules can be built in a similar way to a human scheduler by using a set of rules that involve domain knowledge. This paper presents an Estimation of Distribution Algorithm (EDA) for the nurse scheduling problem, which involves choosing a suitable scheduling rule from a set for the assignment of each nurse. Unlike previous work that used Genetic Algorithms (GAs) to implement implicit learnin...

In this paper we present a novel Case-Based Reasoning (CBR) system called CABAROST (CAsed-BAsed ROSTering) which was developed for personnel scheduling problems. CBR is used to capture and store examples of personnel manager behaviour which are then used to solve future problems. Previous examples of constraint violations in schedules and the repairs that were used to solve the violations are s...

T paper is concerned with the problem of determining the optimal size and composition of a permanent workforce needed to run a facility when demand is specified by a workstation group (WSG) for up to 24 hours a day, 7 days a week. For full-time employees, a solution is characterized by a bid job, which consists of a five-day-a-week schedule, a lunch break for all shifts, and a set of WSG task a...

Various real-life planning problems require making upfront decisions before all parameters of the problem have been disclosed. An important special case of such problem especially arises in scheduling and staff rostering problems, where a set of tasks needs to be assigned to an available set of resources (personnel or machines), in a way that each task is assigned to one resource, while no task...