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Tourism is one of the fastest-growing sectors in the world with a shift from mass tourism to personalized travel. Nevertheless, it generates significant environmental impacts. The current events associated with quarantine measures generated by COVID-19 represent, however, a risk for this sector. It is hence necessary to create strategies that allow efficient decision-making for all echelons and actors for a rapid recovery. Tourists are key actors, which makes necessary to facilitate tourism trip planning according to tourists’ preferences as a complex process. In this paper, we propose a novel model of tourist trip planning for heterogeneous preferences in a tourist group and selection of transport modes, in the first instance, while a second step seeks at minimizing the level of CO 2 emissions. A comparison of the two models is made considering the objectives associated with individual tourist benefits and group profit equity, in contrast to the inclusion of the cost of CO 2 emissions. A numerical comparison is carried out with a total of 546 data sets. Results illustrate the conflict between those objectives by generating an inverse relationship between the individual and group profit equity of tourists, in addition to individual benefit and emission minimization.

The main concern in city logistics is the need to optimize the movement of goods in urban contexts, and to minimize the multiple costs inherent in logistics operations. Inspired by an application in a medium-sized city in Latin America, this paper develops a bi-objective mixed linear integer programming (MILP) model to locate different types of urban logistics spaces (ULS) for the configuration of a two-echelon urban distribution system. The objective functions seek to minimize the costs associated with distance traveled and relocation, in addition to the costs of violation of time windows. This model considers heterogeneous transport, speed assignment, and time windows. For experimental evaluation, two operational scenarios are considered, and Pareto frontiers are obtained to identify the efficient non-dominated solutions to select the most feasible ones from such a set. A case study of a distribution company of goods for supermarkets in the city of Barranquilla, Colombia, is also used to validate the proposed model. These solutions allow decision-makers to define the configuration of ULS networks for urban product delivery.

Tourism has direct and indirect implications for CO2 emissions. Therefore, it is necessary to develop tourism management based on sustainable tourism, mainly in the transport process. Tourist itinerary planning is a complex process that plays a crucial role in tourist management. This type of problem, called the tourist trip design problem, aims to build personalised itineraries. However, planning tends to be biased towards group travel with heterogeneous preferences. Additionally, much of the information needed for planning is vague and imprecise. In this paper, a new model for tourist route planning is developed to minimise CO2 emissions from transportation and generate an equitable profit for tourists. In addition, the model also plans group routes with heterogeneous preferences, selects transport modes, and addresses uncertainty from fuzzy optimisation. A set of numerical tests was carried out with theoretical and real-world instances. The experimentation develops different scenarios to compare the results obtained by the model and analyse the relationship between the objectives. The results demonstrate the influence of the objectives on the solutions, the direct and inverse relationships between objectives, and the fuzzy nature of the problem.

La producción de leche es un renglón importante dentro del sector agropecuario y la economía de un país. En México, el aporte del sector agropecuario al producto interno bruto (PIB) nominal es del 4,2 %, con una participación del 30,2 % de la ganadería. Este tipo de producción presenta diversos sistemas mejorados para aumentar la tasa de rendimiento. Sin embargo, es necesario conocer los costos de producción asociados a la alimentación de los bovinos en términos de materia seca consumida. En esta investigación, realizamos el análisis de los costos variables de alimentación dentro del proceso de producción de leche para vacas de alta y baja producción en un sistema bovino semiespecializado. Se desarrollaron procesos de diagnóstico y levantamiento de la información, análisis bromatológico, análisis de producción láctea, cálculo de los costos asociados y, por último, evaluación de reducción de costos bajo la metodología multicriterio de proceso de análisis jerárquico (AHP, por sus siglas en inglés). Se calcularon los costos de alimentación asociados a forraje, ensilado y concentrado, los cuales alcanzan el 20,3 % y 21,9 % de los ingresos totales por venta de leche para grupos de vacas de alta y baja producción, respectivamente. Determinamos que la estrategia de reducción de costos que genera mejores resultados, en cuanto a criterios de productividad, eficiencia, ambiente y factores financieros, corresponde a elaboración de diferentes dietas según la tasa de producción de leche. El ahorro asociado a esta estrategia demuestra un potencial de disminuir los costos anuales de alimentación hasta en USD 444 para las vacas objeto de estudio.

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