Personne :
Ruiz, Angel

En cours de chargement...
Photo de profil
Adresse électronique
Date de naissance
Projets de recherche
Structures organisationnelles
Nom de famille
Université Laval. Faculté des sciences de l'administration
Identifiant Canadiana

Résultats de recherche

Voici les éléments 1 - 10 sur 11
  • Publication
    Accès libre
    Strategies to reduce waiting times in outpatient rehabilitation services for adults with physical disabilities : a systematic literature review
    (Sage, 2022-02-12) Dupuis, Frédérique; Déry, Julien; Lucas de Oliveira, Fabio Carlos; Gagnon, Rose; Harding, Katherine; Camden, Chantal; Roy, Jean-Sébastien; Lettre, Josiane; Hudon, Anne; Beauséjour, Marie; Pinard, Anne-Marie; Bath, Brenna; Deslauriers, Simon; Lamontagne, Marie-Eve; Feldman, Debbie; Routhier, François; Desmeules, François; Hébert, Luc J.; Miller, Jordan; Ruiz, Angel; Perreault, Kadija
    Objective: Identifying effective strategies to reduce waiting times is a crucial issue in many areas of health services. Long waiting times for rehabilitation services have been associated with numerous adverse effects in people with disabilities. The main objective of this study was to conduct a systematic literature review to assess the effectiveness of service redesign strategies to reduce waiting times in outpatient rehabilitation services for adults with physical disabilities. Methods: We conducted a systematic review, searching three databases (MEDLINE, CINAHL and EMBASE) from their inception until May 2021. We identified studies with comparative data evaluating the effect of rehabilitation services redesign strategies on reducing waiting times. The Mixed Methods Appraisal Tool was used to assess the methodological quality of the studies. A narrative synthesis was conducted. Results: Nineteen articles including various settings and populations met the selection criteria. They covered physiotherapy (n = 11), occupational therapy (n = 2), prosthetics (n = 1), exercise physiology (n = 1) and multidisciplinary (n = 4) services. The methodological quality varied (n = 10 high quality, n = 6 medium, n = 3 low); common flaws being missing information on the pre-redesign setting and characteristics of the populations. Seven articles assessed access processes or referral management strategies (e.g. self-referral), four focused on extending/modifying the roles of service providers (e.g. to triage) and eight changed the model of care delivery (e.g. mode of intervention). The different redesign strategies had positive effects on waiting times in outpatient rehabilitation services. Conclusions: This review highlights the positive effects of many service redesign strategies. These findings suggest that there are several effective strategies to choose from to reduce waiting times and help better respond to the needs of persons experiencing physical disabilities.
  • Publication
    Accès libre
    On sequencing policies for unit-load automated storage and retrieval systems
    (Taylor & Francis, 2013-09-14) Gagliardi, Jean-Philippe; Ruiz, Angel; Renaud, Jacques
    Automated Storage and Retrieval System (AS/RS) performance highly depends on the characteristics of the mechanical equipment. However, once the system has been physically implemented, achieving its maximum efficiency depends on the way the system is operated. This paper shows that request sequencing (i.e. planning the order in which storage and retrieval requests are performed) is of paramount importance in AS/RS performance. This paper reviews and adapts the most popular storage and sequencing policies to dynamic contexts, and then it proposes a ‘sequencing mathematical model’ (SMM) to simultaneously solve the sequencing and storage location problems. Extensive computational results based on a thorough simulation experiment plan confirm that performing the requests in the right sequence can have a positive impact on AS/RS performance. Our results show that the proposed SMM regularly outperforms other methods. When used in a dynamic context, the proposed SMM may yield up to a 25% reduction in average travel-time compared to the situation where a no-sequencing method is applied.
  • Publication
    Accès libre
    Solving the vehicle routing problem with lunch break arising in the furniture delivery industry
    (Palgrave, 2016-09-16) Gagliardi, Jean-Philippe; Ruiz, Angel; Renaud, Jacques; Coelho, Leandro C.
    In this paper, we solve the Vehicle Routing Problem with Lunch Break (VRPLB), which arises when drivers must take pauses during their shift, for example, for lunch breaks. Driver breaks have already been considered in long haul transportation when drivers must rest during their travel, but the underlying optimization problem remains difficult and few contributions can be found for less than truckload and last mile distribution contexts. This problem, which appears in the furniture delivery industry, includes rich features such as time windows and heterogeneous vehicles. In this paper, we evaluate the performance of a new mathematical formulation for the VRPLB and of a fast and high performing heuristic. The mixed integer linear programming formulation has the disadvantage of roughly doubling the number of nodes, and thus significantly increasing the size of the distance matrix and the number of variables. Consequently, standard branch-and-bound algorithms are only capable of solving small-sized instances. In order to tackle large instances provided by an industrial partner, we propose a fast multi-start randomized local search heuristic tailored for the VRPLB, which is shown to be very efficient. Through a series of computational experiments, we show that solving the VRPLB without explicitly considering the pauses during the optimization process can lead to a number of infeasibilities. These results demonstrate the importance of integrating drivers pauses in the resolution process.
  • Publication
    Accès libre
    Relief distribution networks : a systematic review
    (Kluwer, 2014-04-06) Anaya Arenas, Ana Maria; Ruiz, Angel; Renaud, Jacques
    In the last 20 years, Emergency Management has received increasing attention from the scientific community. Meanwhile, the study of relief distribution networks has become one of the most popular topics within the Emergency Management field. In fact, the number and variety of contributions devoted to the design or the management of relief distribution networks has exploded in the recent years, motivating the need for a structured and systematic analysis of the works on this specific topic. To this end, this paper presents a systematic review of contributions on relief distribution networks in response to disasters. Through a systematic and scientific methodology, it gathers and consolidates the published research works in a transparent and objective way. It pursues three goals. First, to conduct an up-to-date survey of the research in relief distribution networks focusing on the logistics aspects of the problem, which despite the number of previous reviews has been overlooked in the past. Second, to highlight the trends and the most promising challenges in the modeling and resolution approaches and, finally, to identify future research perspectives that need to be explored.
  • Publication
    Accès libre
    Importance of fairness in humanitarian relief distribution
    (Taylor & Francis, 2019-01-24) Anaya Arenas, Ana Maria; Ruiz, Angel; Renaud, Jacques
    This article is inspired by some of the challenges faced by non-governmental organizations in the distribution of humanitarian relief to vulnerable rural communities. A major concern of these organizations is to warrant that relief is distributed in an impartial and transparent way, which gives rise to the notion of fairness. This article thus discusses the importance of fairness in relief distribution and how it can be defined, especially in a context where delivery of vital items must be ensured periodically. We also propose some performance indicators to measure fairness, which can be useful to organizations that are held accountable for the impartiality of their decisions. Finally, an empirical study of an academic case, inspired by a rural aid distribution problem, is used to analyse how different mathematical formulations may contribute in helping crisis managers integrate fairness or equity in their decisions.
  • Publication
    Clinical pathway efficiency for elective joint replacement surgeries : a case study
    (Emerald/MCB University Press, 2019-05-24) Côté, André; Laberge, Maude; Ruiz, Angel
    Purpose – The purpose of this paper is to define a clinical pathway for total joint replacement (TJR) surgery, estimate the effect of delays between steps of the pathway on wait time for surgery and to identify factors contributing to more efficient operations and challenges to their implementation. Design/methodology/approach – This is a case study with a mixed methods approach. The authors conducted interviews with hospital staff. Data collected in the interviews and through on-site observation were analyzed to map the TJR process and identify the steps of the care pathway. The authors extracted and analyzed data (time stamps) from 60 hospital patient records for each step in the pathway and ran a regression on the duration of the whole trajectory. Findings – There were wide variations in the delays observed between the seven steps identified. The delay between Step 1 and Step 2 was the only significant variable in predicting the total wait time to surgery. In one hospital, one delay explained 50 percent of the variation. There was misalignment between findings from the qualitative data in terms of strategies implemented to increase efficiency of the clinical pathway to the quantitative data on delays between the steps. Research limitations/implications – The study identified the clinical pathway from the consultation with an orthopaedic surgeon to the surgery. However, it did not go beyond the surgery. Future research could investigate the relationship between specific processes and delays between steps of the process and patient outcomes, including length of stay, mobilization and functionality in activities of daily living, as well as potential complications from surgery, readmission and the services required after the patient was discharged. Practical implications – Wait times can be addressed by implementing strategies at the health system level or at the organizational level. The authors found and discuss areas where there could be efficiency gains for health care organizations. Social implications – Stakeholders in care processes are diverse and they each have their preferences in how they practice (in the case of providers) and how they perceive and wish to respond adequately to patients’ needs in contexts that have different norms and approaches. The approach in this study enables a better understanding of the processes, the organizational culture and how these may affect each other. Originality/value – Our mixed methods enabled a process mapping and the identification of factors that significantly affected the efficiency of the TJR surgery process. It combines methods from process engineering with health services and management research. To some extent, this study demonstrates that although managers can define and enforce processes, organizational culture and practices are harder to influence.
  • Publication
    Accès libre
    An iterated local search for the biomedical sample transportation problem with multiple and interdependent pickups
    (Pergamon, 2019-12-14) Anaya Arenas, Ana Maria; Prodhon, Caroline; Ruiz, Angel; Renaud, Jacques
    This paper addresses a new version of the biomedical sample transportation problem, as a vehicle routing problem with precedence constraints arising in the context of health care logistics, and proposes an iterated local search algorithm to solve it. This new version is more realistic and complex since it considers the collection centers’ opening hours and the moment at which they are visited as decision variables, granting additional flexibility to elaborate more efficient routes. Indeed, this problem is harder to model and to solve than its previous version because the constraint on the short samples’ lifetime leads to interdependency between successive pickups at each collection center. A metaheuristic is thus proposed to solve real-life instances. Numerical experiments confirm (1) the value of simultaneously planning routes, opening hours, and visit hours (which is new in the literature) and (2) the efficiency of the proposed algorithm to solve this problem.
  • Publication
    Accès libre
    Sequencing approaches for multiple-aisle automated storage and retrieval systems
    (Taylor & Francis, 2015-02-18) Gagliardi, Jean-Philippe; Ruiz, Angel; Renaud, Jacques
    Automated storage and retrieval systems (AS/RS) are used in high velocity distribution centres to provide accurate and fast order processing. While almost every industrial system is comprised of many aisles, most of the academic research on the operational aspects of AS/RS is devoted to single-aisle systems, probably due to the broadly accepted hypothesis proposing that an m aisles system can be modelled as m 1-aisle independent systems. In this article, we present two multi-aisles sequencing approaches and evaluate their performance when all the aisles are managed independently first, and then in a global manner. Computational experiments conducted on a multi-aisle AS/RS simulation model clearly demonstrate that a multi-aisle system cannot be accurately represented by multiple single-aisle systems. The numerical results demonstrate that, when dealing with random storage, globally sequencing multi-aisle AS/RS leads to makespan reductions ranging from 14 to 29% for 2- and 3-aisle systems, respectively.
  • Publication
    Accès libre
    A system dynamics model to support long-term bearability of the healthcare system: the case of the province of Quebec
    (MDPI, 2019-12-09) Lagarda, Ernesto; Ruiz, Angel
    This paper describes the modeling efforts devoted by the Ministry of Health and Social Services of Québec, Canada (MSSS), to ensure the long-term bearability of their care system. To this end, it studies the relationships between four entities that self-regulate and interact to form the complex care-providing system: (1) universities; (2) hospitals and doctors; (3) the ministry; and (4) society. The first phase of this research focuses on modeling such relationships and relies on the system dynamics methodology to adequately capture the long-term dynamics of the system. The methodology encompasses three phases: (a) determination of the critical variables and parameters of each entity; (b) development of the causal diagram of each entity; and (c) integration of the individual causal diagrams to form the global system diagram. The final casual model illustrates and explains the relationships between all the entities and constitutes an excellent tool to support experts during discussions or focus groups where critical variables that positively or negatively affect the system can be evaluated. We intend to enrich this casual model in a further phase of the project, which will hopefully lead to a simulation and scenario analysis tool that can be used to support managers in their long-term decision-making process.
  • Publication
    Accès libre
    Assessing the impact of patient prioritization on operating room schedules
    (Elsevier, 2019-11-15) Oliveira, Mariana; Bélanger, Valérie; Ruiz, Angel; Marques, Inês
    This paper proposes an integrated approach to merge patient prioritization and patient schedulingto improve access to services in an elective (i.e., non-urgent) context. In particular, we assume thatpatients are included on a waiting list for a given surgery, and that every patient on the list hasreceived a ‘‘utility score’’, which is aproxyfor the relative urgency with regards to the other patientson the list. A mathematical model is formulated to solve the patient scheduling problem, i.e., thesimultaneous assignment of surgery sessions to surgeons and patients to surgeons, in such a way thatthe total utility is maximized along with other practical requirements. The model has been appliedto a testbed of randomly generated instances, inspired by the context of the Urology Department ata University Hospital in Quebec City. Experiments have been conducted to analyze both the short-and medium-term behaviors of the proposed approach. The numerical results confirm that the use ofan objective function designed to maximize utility does not deteriorate the efficiency of the resultingschedules in terms of the number of surgeries performed. They also show that, as expected, higherutility patients are scheduled first, and their waiting time before surgery are shorter than those oflower utility. However, this approach may lead to longer, and even unacceptable waiting times forlow utility patients. To mitigate such an undesirable effect, a dynamic utility updating approach isproposed to progressively increase the utility of patients according to their time spent on the waitinglist. This approach seems to adequately balance the advantages of scheduling patients based on theirutility and the risk of causing too much delay for low priority patients.