The paper studies the bus-journey graphs in the case when they are piecewise expanding and contracting (if described by fathers-sons relations starting with the greatest independent set of nodes). This approach can make it possible to solve the minimization problem of the total service time of crews.
This paper presents a hybrid schedule generation scheme for solving the resource-constrained project scheduling problem. The scheme, which is called the Polarized Adaptive Scheduling Scheme (PASS), can operate in a spectrum between two poles, namely the parallel and serial schedule generation schemes. A polarizer parameter in the range between zero and one indicates how similarly the PASS behaves like each of its two poles. The presented hybrid is...
This paper presents a hybrid schedule generation scheme for solving the resource-constrained project scheduling problem. The scheme, which is called the Polarized Adaptive Scheduling Scheme (PASS), can operate in a spectrum between two poles, namely the parallel and serial schedule generation schemes. A polarizer parameter in the range between zero and one indicates how similarly the PASS behaves like each of its two poles. The presented hybrid is...
The aim of this paper is to show a polynomial algorithm for the problem minimum directed sumcut for a class of series parallel digraphs. The method uses the recursive structure of parallel compositions in order to define a dominating set of orders. Then, the optimal order is easily reached by minimizing the directed sumcut. It is also shown that this approach cannot be applied in two more general classes of series parallel digraphs.
Scheduling examinations in a large university is an increasingly complex problem, due to its size, the growing flexibility of students' curricula and the interest in including a wide set of objectives and constraints. In this paper we present a new algorithm for this problem and its application to a university in Spain.A combination of heuristics, based on Tabu Search, first finds a solution in which no student has two exams simultaneously and then improves it by evenly spacing the exams in the...
En este trabajo se estudia la eficiencia relativa de un conjunto de algoritmos heurísticos, deterministas y aleatorizados, para el problema de la secuenciación de proyectos con limitación de recursos. Se presentan los resultados de un extenso estudio computacional y se aplican tests no paramétricos para contrastar estadísticamente las conclusiones obtenidas.
This paper considers the problem of scheduling n jobs on a single machine. A fixed processing time and an execution interval are associated with each job. Preemption is not allowed. On the basis of analytical and numerical dominance conditions, an efficient integer linear programming formulation is proposed for this problem, aiming at minimizing the maximum lateness (Lmax). Experiments have been performed by means of a commercial solver that show that this formulation is effective on large...
The aim of this paper is to present a new branch and bound method for solving the Multi-Processor Flow-Shop. This method is based on the relaxation of the initial problem to m-machine problems corresponding to centers. Release dates and tails are associated with operations and machines. The branching scheme consists in fixing the inputs of a critical center and the lower bounds are those of the m-machine problem. Several techniques for adjusting release dates and tails have also been introduced....
This note is concerned with the bicriteria scheduling problem on a series-batching machine to minimize maximum cost and makespan. An O(n5) algorithm has been established previously. Here is an improved algorithm which solves the problem in O(n3) time.