Sacramento Quintanilla

Sacramento Quintanilla
University of Valencia | UV · Departamento de Matemáticas para la Economía y la Empresa

PhD Maths

About

32
Publications
3,377
Reads
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1,249
Citations
Citations since 2017
3 Research Items
381 Citations
20172018201920202021202220230204060
20172018201920202021202220230204060
20172018201920202021202220230204060
20172018201920202021202220230204060
Additional affiliations
October 1988 - present
University of Valencia
Position
  • Head of Department

Publications

Publications (32)
Article
Full-text available
This paper addresses a home healthcare routing problem in which doctors and nurses visit patients at their homes to provide services. We consider a real-world home healthcare service arising in a particular hospital in Spain. Doctors and nurses are distributed in teams and travel by taxi; taxis transport a pre-defined set of workers who travel toge...
Article
Full-text available
This paper considers the problem of building a schedule of elective surgery patients for a unit of a hospital. Two phases are followed. In the first phase, a tentative schedule is calculated 2 weeks before the planning period looking to minimise the percentage of tardy patients. Several weight-based short-term objective functions are defined and co...
Article
The warehouse is one of the essential components of logistics and supply chains. The efficiency of the whole chain is affected by the performance of warehouse operations and, more particularly, the storage and retrieval of goods. This paper considers a storage and retrieval problem in a real warehouse with random storage and different types of fork...
Article
A fundamental assumption in the basic RCPSP is that activities in progress are non-preemptable. Some papers reveal the potential benefits of allowing activity interruptions in the schedule when the objective is the makespan minimization. In this chapter we consider the Maxnint_PRCPSP in which it is assumed that activities can be interrupted at any...
Article
In this paper, we study a multi-mode resource-constrained project scheduling problem (RCPSP) which considers time and work generalised precedence relationships with minimal and maximal time lags and due dates where each activity requires only one unit of resource (e. g. a worker, a machine, etc.). To find a feasible solution for this problem is NP-...
Article
The extensive application of emerging technologies is revolutionizing warehouse management. These technologies facilitate working with complex and powerful warehouse management models in which products do not have assigned fixed locations (random storage). Random storage allows the utilization of the available space to be optimized. In this context...
Article
Warehouses are essential components of logistics and supply chains. The performance of warehouse operations significantly affects the efficiency of the whole chain it belongs to. Radio frequency identification (RFID) is an emerging technology capable of providing real-time information about the location and properties of tagged object(s), such as p...
Article
In this paper we present an application of project scheduling concepts and solution procedures for the solution of a complex problem that comes up in the daily management of many company Service Centres. The real problem has been modelled as a multi-mode resource-constrained project scheduling problem with pre-emption, time and work generalised pre...
Article
A recent paper (Ballestín F, Valls V, Quintanilla S. Preemption in resource-constrained project scheduling. European Journal of Operational Research 2008;189:1136–152) revealed the potential benefits of allowing one interruption when scheduling activities in a resource-constrained project. This paper further investigates the effect of interruption...
Article
The Skilled Workforce Project Scheduling Problem (SWPSP) is a complex problem of task scheduling and resource assignment that comes up in the daily management of many company Service Centres (SC). The SWPSP considers many real characteristics faced daily by the SC: client-company service quality agreements that establish maximum dates for the begin...
Conference Paper
Warehouses are essential components of logistics and supply chains. The performance of warehouse operations significantly affects the efficiency of the whole chain it belongs to. Radio frequency identification (RFID) is an emerging technology capable of providing real-time information about the location and properties of tagged object(s), such as p...
Article
The Resource-Constrained Project Scheduling Project (RCPSP), together with some of its extensions, has been widely studied. A fundamental assumption in this basic problem is that activities in progress are non-preemptable. Very little effort has been made to uncover the potential benefits of discrete activity pre-emption, and the papers dealing wit...
Article
In this paper we propose a Hybrid Genetic Algorithm (HGA) for the Resource-Constrained Project Scheduling Problem (RCPSP). HGA introduces several changes in the GA paradigm: a crossover operator specific for the RCPSP; a local improvement operator that is applied to all generated schedules; a new way to select the parents to be combined; and a two-...
Article
Full-text available
This paper deals with a real-life problem that comes up in the daily management of Service Centres. It is a complex resource allocation and task scheduling problem that has to be solved online in a dynamic and uncertain environment. The uncertainty resides both in the task durations and the task arrival times. It is shown that this problem can be f...
Chapter
Due dates are an essential feature of real projects, but little effort has been made in studying the RCPSP with due dates in the activities. This paper tries to bridge this gap by studying two problems: the TardinessRCPSP, in which the objective is total tardiness minimization and the DeadlineRCPSP, in which the due dates are strict (deadlines) and...
Chapter
The justification technique was introduced various decades ago for the resource-constrained project scheduling problem, although it has rarely been used with the problem. Justification is a simple and quick technique which when applied to schedules produces a new schedule that is, at most, as long as the original schedule — and often shorter. A rec...
Article
The objective of this paper is to show that justification is a simple technique that can be easily incorporated in diverse algorithms for the resource-constrained project scheduling problem––improving the quality of the schedules generated without generally requiring more computing time. The results of incorporating this technique in 22 different a...
Article
We present a population-based approach to the RCPSP. The procedure has two phases. The first phase handles the initial construction of a population of schedules and these are then evolved until high quality solutions are obtained. The evolution of the population is driven by the alternative application of an efficient improving procedure for locall...
Article
In this paper, we present a new metaheuristic algorithm for the resource-constrained project-scheduling problem. The procedure is a non-standard implementation of fundamental concepts of tabu search without explicitly using memory structures embedded in a population-based framework. The procedure makes use of a fan search strategy to intensify the...
Article
this paper, we present a population-based approach to the RCPSP . The procedure incorporates various strategies for generating and evolving a population of schedules. The method has two phases. The first phase handles the initial construction of a population of schedules and these are then evolved until high quality solutions are obtained. Random a...
Article
The objective of this paper is to show that justification is a simple technique that can be easily incorporated in diverse algorithms for the resource-constrained project scheduling problem -- improving the quality of the schedules generated without generally requiring more computing time. The results of incorporating this technique in 21 different...
Article
We propose a hybrid genetic algorithm, HGA, for the RCPSP. HGA introduces several changes in the GA paradigm based on the knowledge of the problem. The distinguishing features of our approach are the following: a new peak crossover operator; a specific operator for the RCPSP; and a double justification operator. The latter is a local improvement op...
Article
this paper, we present a population-based approach to the RCPSP . The procedure incorporates various strategies for generating and evolving a population of schedules. The method has two phases. The first phase handles the initial construction of a population of schedules and these are then evolved until high quality solutions are obtained. Random a...
Article
In this paper, we address the problem of minimizing expected total weighted tardiness of jobs that have stochastic interruptions and that are processed on a set of parallel machines. Our research generalizes the problem of scheduling parallel machines to minimize total weighted tardiness. The proposed solution method is based on the scatter search...
Article
Full-text available
In this chapter we address the problem of scheduling the activities of a resource-constrained project, some of which may be interrupted by an uncertain amount of time. The resources may be, for example, machines in a jobshop, computers with specialized software packages (as those needed for engineering designs), or highly specialized technicians.
Article
In this paper we apply the tabu search (TS) technique to a complex machine scheduling problem. The problem can be considered as a generalization of the job-shop problem with both simple and parallel machines, job batches, setup times and release and due dates. The goal is to obtain feasible schedules by minimizing the makespan Cm,, if the problem i...
Article
The Heterogeneous Resource Allocation Problem (HRAP) deals with the allocation of resources, whose units do not all share the same characteristics, to an established plan of activities. Each activity requires one or more units of each resource which possess particular characteristics, and the objective is to find the minimum number of resource unit...
Article
The Heterogeneous Resource Allocation Problem (HRAP) deals with the allocation of resources, whose units do not all share the same characteristics, to an established plan of activities. Each activity requires one or more units of each resource which possess particular characteristics, and the objective is to find the minimum number of resource unit...
Article
We analyze a heterogeneous workforce assignment problem in which the minimum number of workers required to carry out a machine load plan is calculated. The problem is formulated as a restricted vertex colouring problem and a branch and bound algorithm is presented. The special characteristics of the graph to be coloured allow an efficient implement...
Article
We present a modification of the tabu thresholding (TT) approach and apply it to the solution of the generalised restricted vertex colouring problem. Both the bounded and unbounded cases are treated. In our algorithms, the basic TT elements are supplemented with an evaluation function that depends on the best solution obtained so far, together with...
Article
RESUMEN La justificación es una técnica sencilla y rápida que al aplicarla sobre una secuencia del RCPSP produce otra de igual o menor duración. Un artículo reciente pone de manifiesto que su incorporación en los algoritmos heurísticos produce una mejora sustancial de los resultados obtenidos. La generalización de la justificación da origen en el p...
Article
Full-text available
RESUMEN En este trabajo se presentan el análisis del sistema productivo y el software de planificación desarrollado para una empresa valenciana. La cartera de pedidos y el estado de los inventarios alimentan el sistema que planifica las secciones de "atrás hacia adelante", asignando semanalmente los trabajos a realizar en cada una de ellas. La plan...

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