Forecasting Models Selection Mechanism for Supply Chain Demand Estimation

AbstractThe aim of this work is to present a selection mechanism of forecast models to contribute to demand estimation in a supply chain. At present, to estimate a product future demand, several forecast models based on historical information - quantitative and qualitative- are used. When companies face this situation, they select a group of forecast models (usually based on a visual basis of the time series), then estimate, and with the forecast error measurement criteria decide which the best method is. But they always have to estimate over all the selected forecast models. Based on that, this paper introduces an alternative methodology to estimate the best-forecast model without the need to estimate all the forecast models or complement with another technique (visual). To do so, the main theoretical fundaments associated to this new methodology are addressed, and then the methodology itself is presented in order to be applied in two real cases of Chilean companies to finally conclude the results of the described mechanism

Proposal of Two Measures of Complexity Based on Lempel-Ziv for Dynamic Systems: An Application for Manufacturing Systems

The measure of complexity of Lempel-Ziv (LZC) is used for the analysis of time series generated by dynamic systems with the objective of determining its complexity. This work measures LZC of different series coming from periodic functions, probabilistic functions, and chaotic systems. Later, these metrics of complexity are applied to the average of the number of parts in the waiting line in a manufacturing workshop. The results demonstrate the efficiency of the LZC to establish the level of the dynamic behavior of the manufacturing systems, through the time series

Simulación del proceso de inventarios en una poscosecha de rosas de exportación bajo un enfoque de Business Process Management

Few companies in the Colombian floriculture sector manage their inventories, causing stock breaks, causing downtime in key post-harvest operations, causing non-compliance with sales orders and damage to the flower. For this reason, the general objective is to simulate the inventory process handled in the postharvest of rose (Rosa sp.), to find opportunities for improvement. This research work was a case study carried out in an export company of rose bouquets from Cundinamarca, the province with the largest volume of export-type flower production at the national level. The rose postharvest was selected by the indicators of low production. Because this is a descriptive and exploratory investigation, a modeling of the inventory process was carried out, with the help of the managers and an analysis of times and probability of occurrence of the tasks involved. Subsequently, the simulation was done with the inventory process cycle time in Bizagi Modeler®, making a total of 36 replicas. This resulted in a total inventory process cycle time of 9,684 minutes for the Valentine's season, finding that 44 % of the activities can be optimized. Finally, it is concluded that, with the simulation of the inventory process, non-value-added activities can be found, serving as an input in the development of improvement strategies.Pocas empresas del sector floricultor colombiano hacen una gestión de sus inventarios, lo que redunda en quiebres de stock, tiempos muertos en operaciones clave de la poscosecha, incumplimientos de las órdenes de ventas y daños en la flor. Por esto, se plantea como objetivo general simular el proceso de inventarios manejado en la poscosecha de rosa (Rosa sp.), con el fin de encontrar oportunidades de mejora. Este trabajo de investigación fue un estudio de caso realizado en una empresa exportadora de ramos de rosa de Cundinamarca, ya que este departamento es el que tiene el mayor volumen de producción de flores tipo exportación a nivel nacional. Para ello, se seleccionó la poscosecha de rosa por los indicadores de producción bajos. De esta manera, se planteó una investigación descriptiva y exploratoria, y se hizo una modelación del proceso de inventarios, con ayuda de los jefes y un análisis de tiempos y de probabilidad de ocurrencia de las tareas involucradas. Posteriormente, se hizo la simulación con el tiempo de ciclo de proceso de inventario en Bizagi Modeler®, llevando a cabo un total de 36 réplicas. Esto dio como resultado un tiempo total de ciclo de proceso de inventarios de 9.684 minutos para la temporada de San Valentín, encontrando que el 44 % de las actividades pueden ser optimizadas. Finalmente, se concluye que, con la simulación del proceso de inventarios, se pueden encontrar actividades de no valor agregado, sirviendo de insumo en la elaboración de estrategias de mejora

Izaña Atmospheric Research Center. Activity Report 2019-2020

Editors: Emilio Cuevas, Celia Milford and Oksana Tarasova.[EN]The Izaña Atmospheric Research Center (IARC), which is part of the State Meteorological Agency of Spain (AEMET), is a site of excellence in atmospheric science. It manages four observatories in Tenerife including the high altitude Izaña Atmospheric Observatory. The Izaña Atmospheric Observatory was inaugurated in 1916 and since that date has carried out uninterrupted meteorological and climatological observations, contributing towards a unique 100-year record in 2016. This reports are a summary of the many activities at the Izaña Atmospheric Research Center to the broader community. The combination of operational activities, research and development in state-of-the-art measurement techniques, calibration and validation and international cooperation encompass the vision of WMO to provide world leadership in expertise and international cooperation in weather, climate, hydrology and related environmental issues.[ES]El Centro de Investigación Atmosférica de Izaña (CIAI), que forma parte de la Agencia Estatal de Meteorología de España (AEMET), representa un centro de excelencia en ciencias atmosféricas. Gestiona cuatro observatorios en Tenerife, incluido el Observatorio de Izaña de gran altitud, inaugurado en 1916 y que desde entonces ha realizado observaciones meteorológicas y climatológicas ininterrumpidas y se ha convertido en una estación centenaria de la OMM. Estos informes resumen las múltiples actividades llevadas a cabo por el Centro de Investigación Atmosférica de Izaña. El liderazgo del Centro en materia de investigación y desarrollo con respecto a las técnicas de medición, calibración y validación de última generación, así como la cooperación internacional, le han otorgado una reputación sobresaliente en lo que se refiere al tiempo, el clima, la hidrología y otros temas ambientales afines

Treatment with tocilizumab or corticosteroids for COVID-19 patients with hyperinflammatory state: a multicentre cohort study (SAM-COVID-19)

Objectives: The objective of this study was to estimate the association between tocilizumab or corticosteroids and the risk of intubation or death in patients with coronavirus disease 19 (COVID-19) with a hyperinflammatory state according to clinical and laboratory parameters. Methods: A cohort study was performed in 60 Spanish hospitals including 778 patients with COVID-19 and clinical and laboratory data indicative of a hyperinflammatory state. Treatment was mainly with tocilizumab, an intermediate-high dose of corticosteroids (IHDC), a pulse dose of corticosteroids (PDC), combination therapy, or no treatment. Primary outcome was intubation or death; follow-up was 21 days. Propensity score-adjusted estimations using Cox regression (logistic regression if needed) were calculated. Propensity scores were used as confounders, matching variables and for the inverse probability of treatment weights (IPTWs). Results: In all, 88, 117, 78 and 151 patients treated with tocilizumab, IHDC, PDC, and combination therapy, respectively, were compared with 344 untreated patients. The primary endpoint occurred in 10 (11.4%), 27 (23.1%), 12 (15.4%), 40 (25.6%) and 69 (21.1%), respectively. The IPTW-based hazard ratios (odds ratio for combination therapy) for the primary endpoint were 0.32 (95%CI 0.22-0.47; p < 0.001) for tocilizumab, 0.82 (0.71-1.30; p 0.82) for IHDC, 0.61 (0.43-0.86; p 0.006) for PDC, and 1.17 (0.86-1.58; p 0.30) for combination therapy. Other applications of the propensity score provided similar results, but were not significant for PDC. Tocilizumab was also associated with lower hazard of death alone in IPTW analysis (0.07; 0.02-0.17; p < 0.001). Conclusions: Tocilizumab might be useful in COVID-19 patients with a hyperinflammatory state and should be prioritized for randomized trials in this situatio

Analysis of the Value of Information and Coordination in a Dyadic Closed Loop Supply Chain

Purpose: This article analyzes the value of information and coordination in a closed loop supply chain (CLSC) and discusses the benefits of a global or local optimization approach and the impact of uncertainty. Methodology: A theoretical dyadic closed loop supply chain is analyzed where the manufacturer re-manufactures products returned by customers, producing &ldquo;as good as new products&rdquo; for the retailer. Twelve coordination scenarios were analyzed. For the definition of these scenarios, a framework based on two criteria was proposed: value of information and perimeter of decision making. Findings: Information on returns leads to lower costs than information on demand. In the presence of complete or partial coordination between the actors in the supply chain, it is preferable to have low product return rates. However, if we are in the complete absence of coordination, high rates of return are more convenient as they function as a buffer against uncertainties. The perimeter of decision making (global or local optimization) does not significantly improve the supply chain performance in relation to its costs. Only the exchange of information improves its performance. Therefore, companies should make efforts to exchange information, first, on their lot sizes, then on their returns and finally, on the customer demand. Originality: The novelty of our work relies on an analysis of the closed loop supply chain performance with the simultaneous presence of information, coordination, and uncertainty

Cost of Capital Estimation for Highway Concessionaires in Chile

In this paper, we present the cost of capital estimation for highway concessionaires in Chile. We estimated the cost of equity and the cost of debt and determined the capital structure for each one of twenty-four concessionaires that operate highways. We based our estimations on the developments of Sharpe (1964), Modigliani and Miller (1958), and Maquieira (2009), which were also compared with the Brusov et al. (2015) developments. We collected stock prices for different highway concessionaires around the world from Google Finance and Reuters’ websites in order to determine the Beta of equity using a representative company. After that, we estimated the cost of equity considering Hamada (1969) and a Capital Asset Pricing Model. Then, we estimated the cost of capital using the cost of debt and the capital structure of Chile’s highway concessionaires. With all above, we were able to determine the Weighted Average Cost of Capital (WACC) for highway concessions which ranges from 5.49 to 6.62%

University governance: the new uncertainties in post-pandemic ways of working

La pandemia ha llevado a reflexionar sobre adecuaciones en las jornadas de trabajo, reduciendo los tiempos de presencialidad y transitando aceleradamente a sistemas de teletrabajo y trabajo remoto, lo anterior ha obligado a los sistemas de gobierno universitario a flexibilizar los sistemas de seguimiento y control, pero al mismo tiempo ha generado que trabajadores y trabajadoras aumenten el tiempo empleado en el desarrollo de sus actividades con los desafíos y tareas encomendadas.&nbsp; Este ensayo revisa los elementos asociados a la reducción de la jornada laboral y los desafíos que esta nueva normalidad acarrea para los gobiernos universitarios luego de la capacitación e instalación de sistemas robustos que permitan realizar las mismas tareas fuera del espacio de la organización.The pandemic has led to reflection on adjustments in working hours, reducing face-to-face times and moving rapidly to teleworking and remote work systems, the foregoing has forced university government systems to make monitoring and control systems more flexible, but at the same time, it has generated that workers increase the time spent in the development of tasks to meet the challenges and tasks entrusted. This essay reviews the elements associated with the reduction of working hours and the challenges that this new normal entails for university governments after the training and installation of robust systems that allow the same tasks to be carried out outside the organization's space