New efficient constructive heuristics for the hybrid flowshop to minimise makespan: A computational evaluation of heuristics

This paper addresses the hybrid flow shop scheduling problem to minimise makespan, a well-known scheduling problem for which many constructive heuristics have been proposed in the literature. Nevertheless, the state of the art is not clear due to partial or non homogeneous comparisons. In this paper, we review these heuristics and perform a comprehensive computational evaluation to determine which are the most efficient ones. A total of 20 heuristics are implemented and compared in this study. In addition, we propose four new heuristics for the problem. Firstly, two memory-based constructive heuristics are proposed, where a sequence is constructed by inserting jobs one by one in a partial sequence. The most promising insertions tested are kept in a list. However, in contrast to the Tabu search, these insertions are repeated in future iterations instead of forbidding them. Secondly, we propose two constructive heuristics based on Johnson’s algorithm for the permutation flowshop scheduling problem. The computational results carried out on an extensive testbed show that the new proposals outperform the existing heuristics.Ministerio de Ciencia e Innovación DPI2016-80750-

Operating theatre planning and scheduling in real-life settings.Problem analysis, models, and solution procedures

Falta palabras claveNowadays health care organizations experience an increasing pressure in order to provide their services at the lowest possible costs as a response to the combination of restrictive budgets, increasing waiting lists, and the aging of the population. In general, hospital resources are expensive and scarce, being the operating theatre the most critical and expensive resource. In most hospitals, the operating theatre is a complex system composed of operating rooms (ORs) together with their specialized equipment, preoperative and postoperative facilities and, finally, a diversity of human resources, including surgeons, anesthetists, nurses, etc. To handle such complexity, decisions related to operating theatre management are usually decomposed into three hierarchical decision levels, i.e.: strategic, tactical and operational. At the strategic level, hospital managers set the volume and the mix of surgeries that will be performed over a long-term horizon (typically, a year) to keep up acceptable size of waiting lists while achieving cost targets, thus making long-term decisions related to the dimensioning of surgical facilities (e.g. build new ORs, adding new recovery beds, etc.), the hiring of surgical staff (e.g. surgeons, nurses, etc.), the purchase of novel surgical devices, and the amount of operating theatre resources required by surgical specialties to perform their surgeries (OR time, number of beds, etc.). Once decisions at strategic level have been made, the operating theatre resources are allocated over a medium-term planning horizon (ranging from few weeks to 6 months) in the tactical level. Since the OR is both a bottleneck and the most expensive facility for most hospitals, surgical specialties are first assigned to OR days (i.e. a pair of an OR and a day) over the planning horizon, until the OR time allocated to each surgical specialty in the strategic level is reached. Then, the above assignment defines aggregate resource requirements for specialties, such as the demand of nurses, drugs, diagnostic procedures, laboratory tests, etc. Finally, the working shifts of human resources and their workload (e.g. the number of surgeries allocated to each surgeon) are defined over the medium-term planning horizon in order to achieve the volume of surgeries set by hospital managers. Finally, the surgical schedule is determined over a short-term planning horizon (ranging from few days to few weeks) at the operational level. The operational level is usually solved into two steps. The first step involves the determination of the date and the OR for a set of surgeries in the waiting list; while in the second step, a sequence of surgeries for each OR within each day in the planning horizon is obtained. Note that only a set of surgeries will be performed during the planning horizon due to capacity constraints (both facilities and human resources). The decomposition of the operational level into the two aforementioned steps intends to reduce the complexity of the resulting problem, although the quality of the so-obtained surgery schedule may be reduced due to the high interdependence among these two steps, being the integrated approach a popular topic of research. At the operational level, a feature greatly influencing the performance is the uncertainty in the surgical activities, as frequently large discrepancies between the scheduled duration and the real duration of the surgeries appear, together with the availability of the resources reserved for emergency arrivals. Despite the importance and the complexity of these hierarchical levels, decisions in practice are usually made according to the decision makers’ experience without considering the underlying optimization problems. Furthermore, the lack of usage of decision models and solution procedures causes the decision makers to consume long times on performing management tasks (e.g. determine the surgical schedule, react to unforeseen events, carry out what-if analyses, etc.), instead of healthcare tasks. The context discussed above stresses the need to provide healthcare decision makers with advanced operations research techniques (i.e. models and solution procedures) in order to improve the efficiency of the operating theatre resources and the quality of the healthcare services at the operational level. This Thesis is aimed at this goal

Gestión del conocimiento en el ámbito sanitario: revisión de la literatura.

En el ámbito sanitario, la toma de decisiones desempeña un papel fundamental a la hora de garantizar una asistencia sanitaria de calidad. Con la aparición de nuevas técnicas, como la gestión del conocimiento (Knowledge Management), se facilita la conversión de la información relativa a pacientes (pruebas clínicas, historial, resolución de casos, etc.) en conocimiento, haciendo posible la integración de éste en un sistema de soporte a la toma de decisiones en el ámbito sanitario. En este trabajo se muestran los resultados preliminares (arquitecturas, aplicaciones y herramientas) de una revisión sistemática de la gestión del conocimiento en el ámbito sanitario

A survey of parallel hybrid applications to the permutation flow shop scheduling problem and similar problems

Parallel algorithms have focused an increased interest due to advantages in computation time and quality of solutions when applied to industrial engineering problems. This communication is a survey and classification of works in the field of hybrid algorithms implemented in parallel and applied to combinatorial optimization problems similar to the to the permutation flowshop problem with the objective of minimizing the makespan, Fm|prmu|Cmax according to the Graham notation, the travelling salesman problem (TSP), the quadratic assignment problem (QAP) and, in general, those whose solution can be expressed as a permutation

Modelos para la resolución de la programación de quirófanos

3rd International Conference on Industrial Engineering and Industrial Management XIII Congreso de Ingeniería de Organización Barcelona-Terrassa, September 2nd-4th 200

Planificación quirúrgica: revisión de la literatura

La realización de intervenciones quirúrgicas en los hospitales es una actividad crucial tanto desde un punto de vista social como económico. Por un lado, mejora la calidad de vida del paciente, mientras que por otro se estima que genera alrededor del 70% de los ingresos, y representa en torno al 40% de los costes de un hospital. El quirófano -Operating Room (OR)- es una sala acondicionada para realizar intervenciones quirúrgicas, que puede consumir entre el 10-15% del presupuesto de un hospital, siendo la instalación más cara, y constituyendo un cuello de botella para la mayoría de hospitales (Jebali et al. ,2006). Por tanto, la correcta gestión de los ORs es un factor importante en la gestión de los hospitales, puesto que son un recurso limitado por su propia capacidad y por los recursos materiales y humanos necesarios para su correcto funcionamiento. El objetivo de este trabajo es caracterizar los problemas de decisión involucrados en la planificación quirúrgica. Para ello, se ha conducido una revisión sistemática para analizar y evaluar los trabajos publicados en el ámbito de la planificación quirúrgica

Encuesta sobre gestión de pedidos en el sector de prefabricados de hormigón

La satisfacción de clientes es uno de los aspectos más importantes para la competitividad de las empresas. La capacidad para responder a los clientes de forma rápida y fiable implica comprometer fechas de entrega ajustadas y cumplirlas. El caso del sector de la prefabricación de hormigón presenta una problemática muy específica en lo que respecta a la gestión de pedidos, ya que los productos se fabrican exclusivamente bajo pedido y compite fundamentalmente en plazos de entrega. En este trabajo, nos centramos en el análisis de este problema realizando una encuesta entre empresas del sector

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Employing fast heuristics for operating room planning

13th International Conference on Project Management and Scheduling Leuven April 1-4, 201

Ajustes en el Proceso de una Unidad Quirúrgica. Un estudio basado en Simulación

4th International Conference on Industrial Engineering and Industrial Management XIV Congreso de Ingeniería de Organización Donostia- San Sebastián , September 8th-10th 2010Presentamos un modelo de simulación basada en Eventos Discretos para manejar la incertidumbre en la duración real de la intervención y en la llegada de pacientes urgentes (grandes quemados) que dislocan la planificación de una unidad de Cirugía Plástica y Grandes Quemados. El modelo desarrollado se implementa en ARENA y se usa para evaluar diferentes rediseños del proceso para protegerse de la influencia de los dos factores considerados. Según nuestro rediseño, son posibles valores aceptables del ratio de uso de los quirófanos, compatibles con un número relativamente pequeño de pacientes no intervenidos según programación. Palabras clave: quirófanos, inducción de anestesia, admisión, simulació