Sustainable maritime crude oil transportation: a split pickup and split delivery problem with time windows

This paper studies a novel sustainable vessel routing problem modeling considering the multi-compartment, split pickup and split delivery, and time windows concepts. In the presented problem, oil tankers transport crude oil from supply ports to demand ports around the globe. The objective is to find ship routes, as well as port arrival and departure times, in a way that minimizes transportation costs. As a second objective, we considered the sustainability aspect by minimizing the vessel energy efficiency operational indicator. Multiple products are transported by a heterogeneous fleet of tankers. Small realistic test instances are solved with the exact method

Inventory Routing Problem in Perishable Supply Chains: A Literature Review

Context: This paper presents a literature review of the Inventories Routing Problem (IRP) applied to supply chains of perishable products. Different approaches to solve this problem are identified and described in terms of structures, models and solution methods.  Method: A systematic literature review is conducted searching in different bibliographic databases and selecting the most relevant studies within the period 2004 to 2017. The results are analyzed so as to propose a taxonomy to classify and compare the different approaches proposed to address this problem. Results: We identified that the majority of studies consider heuristic-based algorithms to solve the problem. Because of its computational complexity the methods resort to metaheuristics and mateheuristics combined with exact methods. Regarding the application to specific supply chains of perishable products, they refer mostly to processed foods, medicines, and human blood. The constraints that differentiate this problem from other types of IRP are useful life and deterioration. Conclusions: The conditions and particularities of the supply chain of perishables products imply the need to consider new variables, parameters, constraints and objective functions; in the reviewed studies it is not clearly defined the differences involved when considering the perishability of the products in the supply chain. Future research should take into account the multiple ways in which deterioration is carried out with factors such as temperature, light, oxygen, humidity and in some cases microorganisms. Also include in the models the cold chain, hygiene standards, air pollution, emissions of greenhouse gases, generation of waste, occupation of roads and other aspects related to City Logistics and Green Logistics

El Problema de Ruteo e Inventarios en Cadenas de Suministro de Perecederos: Revisión de Literatura

Context: This paper presents a literature review of the Inventories Routing Problem (IRP) applied to supply chains of perishable products. Different approaches to solve this problem are identified and described in terms of structures, models and solution methods. Method: A systematic literature review is conducted searching in different bibliographic databases and selecting the most relevant studies within the period 2004 to 2017. The results are analyzed so as to propose a taxonomy to classify and compare the different approaches proposed to address this problem.Results: We identified that the majority of studies consider heuristic-based algorithms to solve the problem. Because of its computational complexity the methods resort to metaheuristics and mateheuristics combined with exact methods. Regarding the application to specific supply chains of perishable products, they refer mostly to processed foods, medicines, and human blood. The constraints that differentiate this problem from other types of IRP are useful life and deterioration.Conclusions: The conditions and particularities of the supply chain of perishables products imply the need to consider new variables, parameters, constraints and objective functions; in the reviewed studies it is not clearly defined the differences involved when considering the perishability of the products in the supply chain. Future research should take into account the multiple ways in which deterioration is carried out with factors such as temperature, light, oxygen, humidity and in some cases microorganisms. Also include in the models the cold chain, hygiene standards, air pollution, emissions of greenhouse gases, generation of waste, occupation of roads and other aspects related to City Logistics and Green Logistics. Contexto: Revisión de literatura del problema de ruteo e inventarios (IRP) aplicado a las cadenas de suministro de productos perecederos. Se identifican y describen los diferentes enfoques en cuanto a estructuras, modelos y métodos de solución.Método: Se realiza una revisión sistemática de la literatura en diferentes bases de datos bibliográficas y se plantea una taxonomía que clasifica las características de los estudios, lo anterior durante el período comprendido entre 2004 y 2017Resultados: Se encuentra que la mayoría de algoritmos propuestos son de carácter heurístico. Debido a complejidad computacional inherente al problema, se usan metaheurísticas y mateheurísticas combinadas con métodos exactos. Se aplican principalmente en alimentos, medicamentos y sangre humana. Las restricciones que diferencian de otros tipos de IRP son las de periodo de vida útil y deterioro.Conclusiones: Las condiciones y particularidades de la cadena de suministro de perecederos hace necesario que se planteen nuevas variables, parámetros, restricciones y funciones objetivo; por otro lado, en los estudios revisados no se establecen diferencias claras al involucrar la perecibilidad de los productos en los modelos. Las futuras investigaciones deberán tener en cuenta las múltiples maneras en las cuales se lleva a cabo el deterioro con factores como la temperatura, la luz, el oxígeno, la humedad y en algunos casos los microorganismos; asimismo, incluir en los modelos la cadena de frío, normas de higiene, contaminación del aire, emisiones de gases de efecto invernadero, generación de residuos, ocupación de vías y demás aspectos relacionados con city logistics y green logistics.

Alternative mixed-integer linear programming models of a maritime inventory routing problem

A single product maritime inventory routing problem is addressed in this paper by exploring the use of continuous and discrete time models. We first present a continuous time model based on time slots for single docks, which is enhanced by reformulating the time assignment constraints. Next, we present a model based on event points to handle parallel docks. A discrete time is also presented based on a single commodity fixed-charge network flow problem (FCNF). All the models are solved for multiple randomly generated instances of different problems to compare their computational efficiency, and to illustrate the solutions obtained</p