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A simulation-based approach for assessing the impact of uncertainty on patient waiting time in the operating room
No full text"© 2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.”International audienceDemand for surgical care is rising worldwide, making the organization of the operating room (OR) a topic of strong interest. During the last two decades, the number of papers on methods for OR planning and scheduling under uncertainty has increased significantly. However, most hospitals neglect this aspect, and use deterministic approaches to schedule their surgical interventions. This leads us to the following research question: “How can discrete-event simulation help assess the impact of uncertainty on patient waiting time in the OR?” To answer this question, we suggest a 3-step methodology: (1) building the deterministic model of the studied OR, (2) implementing uncertainties on activity durations, patient arrival times and patient care requirements, and (3) experimenting with different uncertainty-related scenarios and analyzing the results. We have applied this methodology to a use-case inspired from our partner’s OR: Hôpital Privé de La Baie, from the Vivalto Santé French health group
Simulation and analysis of disruptive events on a deterministic home health care routing and scheduling solution
No full text"© 2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.”International audienceDue to the aging of populations and a desire to relieve the growing demand on medical structures in recent years, the demand for home health care services has been increasing, and the Home Health Care Routing and Scheduling Problem (HHCRSP) is now among the most intensely studied optimization problems. However, most studies on the HHCRSP are based on deterministic models that do not consider any disruptions that may compromise the execution of the schedules. In this paper, we analyze the impact of different sources of disturbances on a deterministic schedule : delays at the start of the route, variability of travel time, and variability of service processing time. Simulation has been chosen because it helps to easily model and analyze complex environments with several sources of variability. Graphical representations and an analysis of variance are presented to interpret the results, leading to several managerial insights and openings for future research
Mise en œuvre de composites par injection de résine thermoplastique réactive dans une préforme fibreuse
No full textIn order to manufacture thermoplastic composites using liquid composite moulding processes (LCM), the use of reactive systems for in-situ synthesis of polyamide 6 (PA6) with ε caprolactam has proved itself a promising possibility due to its low initial viscosity. However, at certain temperatures, crystallization of PA6 has been shown to occur simultaneously with its polymerization. Therefore, in these conditions, crystallization of PA6 depends on its polymerization kinetics. These phenomena affect the viscosity, the temperature, and the repartition between the non-polymerized, the amorphous and the crystallized phases of the reactive system during the process. Furthermore, the dual scale of porosity present in a fibrous preform complicates description of the flow. Therefore, the coupling of these different scales with PA6 synthesis kinetics is source of variabilities in homogeneity and quality of LCM processes manufactured composites.To understand and predict these phenomena and their effects on the quality of manufactured composites, a modelling method taking into account both the resin reactivity and the presence of the preform has been developed. A simulation method of flow in a fibrous preform using Brinkman's equation within the finite volume method (FVM) framework is proposed. At the same time, a new coupling model for polymerization and crystallization is elaborated in order to enable their simulation in 3D geometries. The advantages of this model are demonstrated comparatively to existing models. A viscosity model taking these phenomena into account is also proposed with the help of rheological tests. An experimental injection setup is developped to compare results of the process simulation of reactive thermoplastics injection in a fibrous preform to observations obtained from experimental injections.L'utilisation de systèmes réactifs permettant la synthèse in-situ du polyamide 6 (PA6) à base d'ε-caprolactame est une voie prometteuse pour la fabrication de pièces composites à matrices thermoplastiques par des procédés voie liquide (LCM) grâce à leur faible viscosité initiale. Cependant, il a été montré à certaines températures que la cristallisation du PA6 se déroule simultanément avec sa polymérisation. Dans ces conditions, la cristallisation du PA6 dépend alors de sa cinétique de polymérisation. D'une part, ces phénomènes influent sur la viscosité, la température et la répartition entre les phases non polymérisée, amorphe et cristalline du système réactif durant le procédé. D'autre part, l'écoulement est rendu complexe par la présence de deux échelles de pores dans une préforme fibreuse. Ainsi, le couplage de ces écoulements avec la cinétique de synthèse du PA6 va influencer l'homogénéité et la qualité des pièces fabriquées avec ces procédés. De manière à comprendre et à prédire ces phénomènes et leur effet sur la qualité de fabrication des composites, un modèle prenant en compte l'influence de la réactivité de la résine sur les écoulements dans la préforme a été développé. Une simulation numérique du procédé basée sur la méthode des volumes finis (FVM) et la résolution de l'équation de Brinkman en milieu fibreux est proposée. Elle inclut un nouveau modèle de couplage de polymérisation-cristallisation du PA6 qui a été développé afin de permettre la simulation de ces phénomènes dans des géométries 3D. Les avantages de ce modèle sont présentés par comparaison avec des modèles existants. Un modèle prenant en compte l'influence de ces phénomènes sur la viscosité a aussi été élaboré en se basant sur des essais rhéologiques. Un pilote d'injection est développé afin de pouvoir comparer les résultats de la simulation du procédé d'injection de thermoplastiques réactifs avec des observations expérimentales
Framework for collaborative projects: A partners selection case study
No full textInternational audienceIn this paper data of a European strategic alliance (KAAT project) is used to demonstrate the application of the proposed partner selection framework. This paper is aimed at (1) illustrating the approach for measuring similarity, complementarity, and coverage of knowledge, (2) illustrating the approach for evaluating the partners’ history of collaboration, (3) demonstrating the proposed framework using the actual data, and (4) investigating the position of this framework in the forthcoming research as well as in the selection of partners in complex projects in practice
A Tool-based Approach to Analyze Operating Room Schedule Execution: Application to Online Management
No full textInternational audienceThis book is centered around the development of agile, high-performing healthcare institutions that are well integrated into their environment. The aim is to take advantage of artificial intelligence, optimization and simulation methods to provide solutions to prevent, anticipate, monitor and follow public health developments in order to intervene at the right time, using tools and resources that are both appropriate and effective. The focus is on the people involved – the patients, as well as medical, technical and administrative staff – in an effort to provide an efficient healthcare and working environment that meets safety, quality and productivity requirements.Healthcare Systems has been written by healthcare professionals, researchers in science and technology as well as in the social sciences and humanities from various French-speaking countries. It explores the challenges and opportunities presented by digital technology in our practices, organizations and management techniques
Du diagnostic organisationnel au pilotage prédictif des parcours patients à l'hôpital: Une proposition de système cyber-physique hospitalier à base de doubles numériques
No full textL'hôpital est un système particulièrement complexe. Ses missions sont orchestrées par un bouquet de processus composé d'une multitude d'activités réalisées dans une organisation structurée par des services souvent fortement cloisonnés, au travers desquels les patients suivent de nombreux parcours très variés, en étant pris en charge par différentes catégories de ressources humaines. L'incertitude organisationnelle liée au facteur humain est omniprésente et nécessite de prendre au fil de l'eau des décisions opérationnelles, peu souvent centralisées, pour réagir aux dérives et aux perturbations. La qualité des soins et l'excellence médicale sont, à juste titre, les critères prédominants de tout système de santé. Par contre, l'organisation des flux, et en particulier des parcours patients, est un aspect qui a été jusqu'à présent plutôt négligé. Les conséquences sont de plus en plus dramatiques pour les établissements de santé : le surmenage des personnels, même en dehors des périodes de crises sanitaires, et l'insatisfaction des patients face à des temps d'attente jugés trop longs, font que l'hôpital est constamment en tension. Face à une telle situation, on ne peut que constater qu'à l'ère du numérique, la prise en charge d'un patient dans son parcours de soins ne bénéficie pas d'outils de pilotage dignes de ce nom. Il est par exemple très difficile de connaitre en temps réel la volumétrie de patients présents dans l'hôpital ou dans certaines salles, ou leur temps de séjour. Il est encore plus difficile d'estimer de façon fiable les conséquences d'un événement imprévu sur l'organisation à court terme : retard d'un patient ou d'un médecin, urgence, afflux de patients, etc. Ce manuscrit présente tout d'abord des problèmes et des solutions permettant de répondre au besoin de pilotage en temps réel des hôpitaux : les salles de commande, véritables tours de contrôle ou cockpits bardés d'écrans reportant et centralisant toutes les informations utiles à la maitrise de la situation courante, et du passé. En complément, la contribution nouvelle se situe dans le dessein d’un pilotage prédictif : disposer d'un outil d'aide à la décision permettant non seulement de prédire les conséquences à très court terme d'un événement imprévu, et aussi de proposer des solutions à appliquer au plus vite pour atténuer les perturbations qui pourraient survenir si l'on ne cherche pas à contrôler le cours de ces événements. La solution décrite dans ce manuscrit est assimilable à un système cyber-physique à base de trois doubles numériques interconnectés permettant de suivre, de prédire, et d'optimiser les parcours patients dans un hôpital que l’on peut qualifier de 4.0
Long-term creep behavior of a short carbon fiber-reinforced PEEK at high temperature: Experimental and modeling approach
No full textInternational audienceIn this work, the time-dependent mechanical behavior of a short carbon fiber-reinforced PEEK is investigated at temperatures near and above the glass transition temperature and for stresses below the damage threshold. An experimental procedure including creep/recovery tests and dynamic mechanical tests was carried out by varying stress levels, temperatures and fiber orientation. The mechanical behavior is shown to be linear viscoelastic below the damage threshold. Effect of the fiber orientation on elastic and viscoelastic behavior is similar. A procedure involving the time–temperature superposition principle (TTSP) is set to assess the long-term linear viscoelastic behavior and is shown to provide reliable results. A Maxwell Generalized model is used for unidirectional identification of the model’s parameters. It is then implemented via a UMAT in Abaqus with failure criteria for viscoelastic materials from the literature for 3D calculation of industrial parts
Risk knowledge modeling for offer definition in customer-supplier relationships in Engineer-To-Order situations
No full textInternational audienceThis work deals with the customer-supplier relationship and concerns offer definition in Engineer-To-Order situations (ETO), by adopting the supplier point of view. In such cases, when the offer definition relies simply on key design choices without a detailed design, there is a specific risk (ETO-specific risk) that customer expectations cannot be fulfilled. This kind of risk is in addition to the conventional risks (non ETO-specific risk) involved in any delivery process (machine break down, resource not available, scrapped part…). In order to minimize the supplier risk of not being able to complete the offer as accepted and contracted by the customer, a knowledge-based system can be used to assist risk engineering. Consequently, this article proposes two interrelated knowledge modeling contributions. Firstly, a risk knowledge model which, when implemented in a knowledge-based system that supports risk characterization and risk treatment by using knowledge re-use techniques, is proposed and discussed. Secondly, two knowledge typologies for risk characterizations and treatments (both for ETO and non-ETO situations) in order to support risk knowledge, identification and modeling are also proposed and discussed. These contributions are innovative and groundbreaking in terms of both academics and applications: they provide a formal model to structure risk knowledge and a first list of risks and treatments to be taken into account in ETO and non ETO situations. After an introduction that presents the research gap, our objectives and an analysis of related works, our two contributions are described in two sections with respect to ISO31000 recommendations. The first section covers risk identification and evaluation while the second deals with risk treatments
Editorial - Gestion et ingénierie des systèmes hospitaliers à l’ère du numérique et des innovations organisation. GISEH 2020 - 10 ème Conférence Francophone en Gestion et Ingénierie des Systèmes Hospitaliers. Valenciennes, France, du 26-29 octobre 2020.
No full textInternational audienceCe numéro spécial fait suite à la 10ème Conférence Francophone en Gestion et Ingénierie des Systèmes Hospitaliers – GISEH 2020 – qui a eu lieu à Valenciennes et en ligne en Octobre 2020
Lumped chemical kinetic modelling of raw and torrefied biomass under pressurized pyrolysis
No full textInternational audienceAccurate prediction of the yield and composition of pyrolysis products is an important requirement for the design and operation of pyrolysis reactors and gasifiers. In this paper, a new semi-global kinetic reaction scheme is proposed to predict the composition of pyrolytic volatiles (classified as main chemical family groups), non-condensable gases and char derived from both raw and torrefied biomass for a wide range of operating conditions. The model is based on an adjustable mechanistic reaction scheme, which includes a combination of three different sub-mechanisms for the primary pyrolysis of three reference biopolymers (cellulose, hemicelluloses and lignin) and the secondary pyrolysis of their respective intermediates. The extent of primary/secondary reactions is varied according to the main process features (linear heating rate, temperature, pyrolysis time, volatile residence time and pressure). The secondary reactions in the scheme involve liquid-phase reactions of high molecular weight intermediates (producing non-condensable gases, water vapour and secondary char) as well as homogeneous and heterogeneous gas-phase conversion of primary volatiles. The model predictions were validated using experimental data obtained from fast pyrolysis in different micropyrolyzers (at 500–600 °C and heating rates of 27 and 110 °C/s, respectively) and slow pyrolysis in a laboratory-scale high-pressure fixed bed reactor (at 400–600 °C, 7 °C/min and 1, 15 and 30 bar). In general, the comparison of model outputs and experimental data were satisfactory, and the model predicted accurate trends in product distribution for changes of the lignocellulosic composition (the pre-removal of hemicelluloses in the case of torrefied biomass), heating rate and pressure. The model correctly predicted a significant increase in char yield (14.6 wt%) when torrefied instead of raw biomass was pyrolyzed due to the significance of char-forming reactions during pyrolysis of torrefied biomass. Moreover, the model’s reliability was proven through its accurate prediction of various condensate groups in bio-oil produced in a micropyrolyzer (maximum deviation < 4 wt%). Corresponding to the experimental data, the model predictions showed that the effect of pressure was most significant in the range of 1–15 bar (bio-oil yield decreased by 5.4 wt%), whereas no significant effect in bio-oil yield was evident for a pressure increase in the range of 15–30 bar. The CO2 and CO yields were slightly under-predicted by around 3 wt%, attributed to the catalytic effects of inherent inorganics on secondary cracking reactions which were not considered in the reaction scheme. Future work should focus on the validation of the model at temperatures below 400 °C