An approach for the production scheduling problem when lot streaming is enabled at the operational level

By means of the present work, the production scheduling and the lot streaming problems are simultaneously addressed at flexible manufacturing environments. The proposal is based on a Constraint Programming (CP) formulation that can efficiently tackle the scheduling of manufacturing operations and the splitting of lots into smaller sublots. The approach is capable to define the number of sublots for each lot and the number of parts belonging to each sublot, as well as the assignment of the operations on sublots to machines, with their corresponding start and completion times. The CP model can be easily adapted to cope with different problem issues and several operational policies, which constitutes the main novelty of the contribution. A set of case studies were solved in order to validate the proposal and good quality solutions were found when minimizing the makespan.Sociedad Argentina de Informática e Investigación Operativ

An approach for the production scheduling problem when lot streaming is enabled at the operational level

By means of the present work, the production scheduling and the lot streaming problems are simultaneously addressed at flexible manufacturing environments. The proposal is based on a Constraint Programming (CP) formulation that can efficiently tackle the scheduling of manufacturing operations and the splitting of lots into smaller sublots. The approach is capable to define the number of sublots for each lot and the number of parts belonging to each sublot, as well as the assignment of the operations on sublots to machines, with their corresponding start and completion times. The CP model can be easily adapted to cope with different problem issues and several operational policies, which constitutes the main novelty of the contribution. A set of case studies were solved in order to validate the proposal and good quality solutions were found when minimizing the makespan.Sociedad Argentina de Informática e Investigación Operativ

An approach for the production scheduling problem when lot streaming is enabled at the operational level

By means of the present work, the production scheduling and the lot streaming problems are simultaneously addressed at flexible manufacturing environments. The proposal is based on a Constraint Programming (CP) formulation that can efficiently tackle the scheduling of manufacturing operations and the splitting of lots into smaller sublots. The approach is capable to define the number of sublots for each lot and the number of parts belonging to each sublot, as well as the assignment of the operations on sublots to machines, with their corresponding start and completion times. The CP model can be easily adapted to cope with different problem issues and several operational policies, which constitutes the main novelty of the contribution. A set of case studies were solved in order to validate the proposal and good quality solutions were found when minimizing the makespan.Sociedad Argentina de Informática e Investigación Operativ

Planificación de la producción de corto plazo en plantas “batch” multiproducto, multietapa : Un enfoque CP novedoso

Este trabajo aborda el problema de “scheduling” predictivo de una planta industrial “batch” multiproducto, multietapa con unidades disímiles operando en paralelo en cada etapa. Se presenta un modelo de programación con restricciones (CP) que posibilita abordar de manera eficiente este problema. El mismo permite modelar una amplia variedad de características y limitaciones que están presentes en este tipo de ambiente industrial. Se reportan los resultados correspondientes a varios ejemplos de tamaño mediano que ya han sido abordados en la bibliografía del área. Éstos demuestran que el desempeño computacional del modelo es muy bueno, pues se encuentran soluciones óptimas/subóptimas de muy buena calidad en bajos tiempos de CPU.Sociedad Argentina de Informática e Investigación Operativ

Strategic redesign of the forest-based biomass supply chain through optimization and sensitivity analysis

The Forest Biorefinery Supply Chain (FBSC) redesign problem is addressed. A Generalized Disjunctive Programming (GDP) model is constructed and it is reformulated as Mixed Integer Linear Programming (MILP). The proposed superstructure of FBSC scope (i) the strategic location of forest biomassbased biofuel facilities, and its integration with installed traditional forest industries.In addition, the model determine (ii) feedstock harvesting amount at each forest area; and (iii) transportation flows along all FBSC arcs over a multi-period horizon planning. The applicability of the proposed model is demonstrated through a case study considering different uncertainty settings. A series of sensitivity analyses is performed to determine the impact of variations on the proposedFBSC. The variations in the selling price of products, biomass availability, and demand of products are addressed in the sensitivity analysis.Sociedad Argentina de Informática e Investigación Operativ

Programación de la producción a corto plazo y de tareas de mantenimiento preventivo en ambientes "job shop" flexibles

Se aborda el problema de “scheduling” predictivo en plantas industriales de tipo “Job Shop” Flexible para el que se ha desarrollado un modelo basado en programación con restricciones (“Constraint Programming”, CP) que permite obtener una agenda eficiente para un conjunto de partes o “Jobs” conocido de antemano. El modelo considera las características de este tipo de ambiente industrial: recetas de manufactura específicas para cada “Job”, unidades multipropósito y disímiles para llevar a cabo cada operación, tiempos de alistamiento de equipos y de disponibilidad inicial de las máquinas, etc. Además, la formulación considera la necesidad de ejecutar tareas de mantenimiento preventivo en cada equipo. El modelo se ha verificado y validado utilizando diferentes ejemplos de tamaño medio disponibles en la bibliografía, hallándose soluciones de muy buena calidad en bajos tiempos de cómputo, lo que permite inferir las bondades del modelo.Sociedad Argentina de Informática e Investigación Operativa (SADIO

Programación de la producción a corto plazo y de tareas de mantenimiento preventivo en ambientes "job shop" flexibles

Se aborda el problema de “scheduling” predictivo en plantas industriales de tipo “Job Shop” Flexible para el que se ha desarrollado un modelo basado en programación con restricciones (“Constraint Programming”, CP) que permite obtener una agenda eficiente para un conjunto de partes o “Jobs” conocido de antemano. El modelo considera las características de este tipo de ambiente industrial: recetas de manufactura específicas para cada “Job”, unidades multipropósito y disímiles para llevar a cabo cada operación, tiempos de alistamiento de equipos y de disponibilidad inicial de las máquinas, etc. Además, la formulación considera la necesidad de ejecutar tareas de mantenimiento preventivo en cada equipo. El modelo se ha verificado y validado utilizando diferentes ejemplos de tamaño medio disponibles en la bibliografía, hallándose soluciones de muy buena calidad en bajos tiempos de cómputo, lo que permite inferir las bondades del modelo.Sociedad Argentina de Informática e Investigación Operativa (SADIO

Programación de la producción a corto plazo y de tareas de mantenimiento preventivo en ambientes "job shop" flexibles

Se aborda el problema de “scheduling” predictivo en plantas industriales de tipo “Job Shop” Flexible para el que se ha desarrollado un modelo basado en programación con restricciones (“Constraint Programming”, CP) que permite obtener una agenda eficiente para un conjunto de partes o “Jobs” conocido de antemano. El modelo considera las características de este tipo de ambiente industrial: recetas de manufactura específicas para cada “Job”, unidades multipropósito y disímiles para llevar a cabo cada operación, tiempos de alistamiento de equipos y de disponibilidad inicial de las máquinas, etc. Además, la formulación considera la necesidad de ejecutar tareas de mantenimiento preventivo en cada equipo. El modelo se ha verificado y validado utilizando diferentes ejemplos de tamaño medio disponibles en la bibliografía, hallándose soluciones de muy buena calidad en bajos tiempos de cómputo, lo que permite inferir las bondades del modelo.Sociedad Argentina de Informática e Investigación Operativa (SADIO

Why Are Outcomes Different for Registry Patients Enrolled Prospectively and Retrospectively? Insights from the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF).

Background: Retrospective and prospective observational studies are designed to reflect real-world evidence on clinical practice, but can yield conflicting results. The GARFIELD-AF Registry includes both methods of enrolment and allows analysis of differences in patient characteristics and outcomes that may result. Methods and Results: Patients with atrial fibrillation (AF) and ≥1 risk factor for stroke at diagnosis of AF were recruited either retrospectively (n = 5069) or prospectively (n = 5501) from 19 countries and then followed prospectively. The retrospectively enrolled cohort comprised patients with established AF (for a least 6, and up to 24 months before enrolment), who were identified retrospectively (and baseline and partial follow-up data were collected from the emedical records) and then followed prospectively between 0-18 months (such that the total time of follow-up was 24 months; data collection Dec-2009 and Oct-2010). In the prospectively enrolled cohort, patients with newly diagnosed AF (≤6 weeks after diagnosis) were recruited between Mar-2010 and Oct-2011 and were followed for 24 months after enrolment. Differences between the cohorts were observed in clinical characteristics, including type of AF, stroke prevention strategies, and event rates. More patients in the retrospectively identified cohort received vitamin K antagonists (62.1% vs. 53.2%) and fewer received non-vitamin K oral anticoagulants (1.8% vs . 4.2%). All-cause mortality rates per 100 person-years during the prospective follow-up (starting the first study visit up to 1 year) were significantly lower in the retrospective than prospectively identified cohort (3.04 [95% CI 2.51 to 3.67] vs . 4.05 [95% CI 3.53 to 4.63]; p = 0.016). Conclusions: Interpretations of data from registries that aim to evaluate the characteristics and outcomes of patients with AF must take account of differences in registry design and the impact of recall bias and survivorship bias that is incurred with retrospective enrolment. Clinical Trial Registration: - URL: http://www.clinicaltrials.gov . Unique identifier for GARFIELD-AF (NCT01090362)

Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362