770 million motorcycles are estimated on the roads. Motorcyclists represent more than 380,000 annual deaths worldwide. 28% of the global fatalities in the roads in 2016. With the increase of the accident rate, studies have been developed within the scientific literature. Bibliometric analysis is applied in the field of motorcycle safety in order to identify relevant publications on risk factors of road crashes and their implications. The information in this research was extracted from Web of Science and Scopus databases between 1947 and May 31, 2018. The study identified the key bibliometric indicators such as publications, authors, journals, countries, institutions, citation and co-citation analysis, subject categories, and co-occurrence of terms. EndNote, Microsoft Excel, Statgraphics Centurion and VOS-viewer software were used for the analysis. In total, 1813 articles were considered. The publications from 2000 to 2017 exhibits an average growth of 9%. The journal "Accident Analysis and Prevention" was the key issue in the publication and citation. The top institutions were the

The replenishment size/production lot size problem both for perfect and imperfect quality products studied in this paper is motivated by the optimal strategy in a three layer supply chain consisting of multiple suppliers, manufacturers and retailers. In this model, each manufacturer produces each product with a combination of several raw materials which are supplied by each supplier. The defective products at suppliers and manufacturers are sent back to the respective upstream members at lower price than the respective purchasing price. Finally, the expected average profits of suppliers, manufacturers and retailers are formulated by trading off set up costs, purchasing costs, screening costs, production costs, inventory costs and selling prices. The objective of this chain is to compare between the collaborating system and Stakelberg game structure so that the expected average profit of the chain is maximized. In a numerical illustration, the optimal solution of the collaborating system shows a better optimal solution than the approach by Stakelberg.

RESUMENEste trabajo presenta una Metodología de Gestión de Inventarios que determina los niveles de integración y colaboración en una cadena de suministro, de tal forma que se generen políticas y estrategias conjuntas para mejorar el desempeño de los actores en la cadena. En ella se definen los cinco pasos para implementar procesos de planificación colaborativa entre los actores de la cadena de suministro y la integración de procesos al interior de los mismos, así como también los indicadores que permitan medir su desempeño como resultado de una estrategia de seguimiento. La metodología es validada en empresas del sector madera y muebles de la ciudad de Barranquilla, en las que se evidencian deficiencias en el manejo del inventario, debido a que no se han adoptado buenas prácticas para gestionar los inventarios de manera colaborativa entre actores de distintos niveles de la cadena de suministro. Los resultados muestran bajos niveles de integración de procesos de gestión de inventarios al interior de las empresas, lo que es el resultado de una baja colaboración e integración de procesos entre actores de diferentes niveles de la cadena de suministro de madera y muebles, lo que permitió definir unas estrategias para mejorar la gestión de inventarios entre las empresas que la conforman.Palabras clave: Cadena de suministro, gestión de inventarios, integración, colaboración. ABSTRACT This paper presents a Methodology of Inventory Management that determines the levels of integration and cooperation in a supply chain, so that policies and joint actions to improve the performance of the actors in the chain strategies are generated. It defined the five steps to implement collaborative planning between actors in the supply chain and integration of processes within the same processes as well as indicators to measure their performance as a result of a monitoring strategy. The methodology is validated in

Waiting time is a crucial performance metric in A&E departments. In this regard, longer waiting times are related to low patient satisfaction, high mortality rates and more severe physical health complications. To analyze patient flow in these departments, discrete-event simulation (DES) has been used; however, its applicatin has not been extended to evaluate the impact of improvement strategies. Therefore, this paper aims to design and pretest operational strategies for better ED care delivery using DES. First, input data analysis is carried out. Afterward, the DES model is developed and validated to establish whether it is statistically comparable with the real-world. Then, performance indicators of the current system are computed and analyzed. Finally, improvement strategies are proposed and evaluated by simulation modelling and statistical tests. A case study of an A&E department from a district general clinic is presented to validate the proposed framework. In particular, we will validate the effectiveness of introducing a triage system (Scenario 3), a strategy that is not currently adopted by the clinic. Results demonstrate that waiting times could be meaningfully diminished based on the proposed approaches within this paper.

Objective: Analyze the road crashes in Cartagena (Colombia) and the factors associated with the collision and severity. The aim is to establish a set of rules for defining countermeasures to improve road safety. Methods: Data mining and machine learning techniques were used in 7894 traffic accidents from 2016 to 2017. The severity was determined between low (84%) and high (16%). Five classification algorithms to predict the accident severity were applied with WEKA Software (Waikato Environment for Knowledge Analysis). Including Decision Tree (DT-J48), Rule Induction (PART), Support Vector Machines (SVMs), Naïve Bayes (NB), and Multilayer Perceptron (MLP). The effectiveness of each algorithm was implemented using cross-validation with 10-fold. Decision rules were defined from the results of the different methods. Results: The methods applied are consistent and similar in the overall results of precision, accuracy, recall, and area under the ROC curve. Conclusions: 12 decision rules were defined based on the methods applied. The rules defined show motorcyclists, cyclists, including pedestrians, as the most vulnerable road users. Men and women motorcyclists between 20-39 years are prone in accidents with high severity. When a motorcycle or cyclist is not involved in the accident, the probable severity is low.