2021
Autores
Esmizadeh, Y; Bashiri, M; Jahani, H; Almada Lobo, B;
Publicação
TRANSPORTATION RESEARCH PART E-LOGISTICS AND TRANSPORTATION REVIEW
Abstract
This paper proposes a multi-objective mixed-integer linear programming to model a cold chain with complementary operations on a hierarchical hub network. Central hubs are linked to each other in the first level of the network and to the star network of the lower-level hubs. As for a case study, different hub levels provide various refreshing or freezing operations to keep the perishable goods fresh along the network. Disruption is formulated by the consideration of stochastic demand and multi-level freshness time windows. Regarding the solution, a genetic algorithm is also developed and compared for competing the large-sized networks.
2021
Autores
Saputro, TE; Figueira, G; Almada Lobo, B;
Publicação
INTERNATIONAL JOURNAL OF PRODUCTION RESEARCH
Abstract
In the current global market, managing supply is not a straightforward process and it becomes even more complex as uncertainty and disruptions occur. In order to mitigate their impact, the selection of suppliers of strategic items should have a more holistic view of the operations in the supply chain. We propose an integrated model for supplier selection, considering inventory management and inbound transportation. We approach this problem, incorporating stochastic demand and suppliers' imperfect quality. Imperfect quality triggers additional costs, including external failure and holding costs. Supply disruptions also affect the suppliers' lead time, resulting in delivery delays. We develop a methodology to address this challenge with simulation-optimisation. A genetic algorithm determines supplier selection decisions, while inventory decisions are computed analytically. Discrete-event simulation is used to evaluate the overall performance, as well as to update the lead time dynamically, according to the disruptions. Finally, sensitivity analysis providing managerial insights reveals that criteria in supplier selection should be given a different priority depending on the characteristics of the items, and the effectiveness of disruption mitigation strategies depends on the disruption characteristics.
2021
Autores
Felicio, S; Hora, J; Maria Campos Ferreira, M; Dangelo, C; Costa, P; Abrantes, D; Silva, J; Coimbra, M; Teresa Galvão Dias, M;
Publicação
Human Systems Engineering and Design (IHSED2021) Future Trends and Applications - AHFE International
Abstract
2021
Autores
Abrantes, D; Maria Campos Ferreira, M; Costa, P; Felicio, S; Hora, J; Dangelo, C; Silva, J; Teresa Galvão Dias, M; Coimbra, M;
Publicação
Human Systems Engineering and Design (IHSED2021) Future Trends and Applications - AHFE International
Abstract
2021
Autores
Barros, H; Pereira, T; Ramos, AG; Ferreira, FA;
Publicação
MATHEMATICS
Abstract
This paper presents a study on the complexity of cargo arrangements in the pallet loading problem. Due to the diversity of perspectives that have been presented in the literature, complexity is one of the least studied practical constraints. In this work, we aim to refine and propose a new set of metrics to measure the complexity of an arrangement of cargo in a pallet. The parameters are validated using statistical methods, such as principal component analysis and multiple linear regression, using data retrieved from the company logistics. Our tests show that the number of boxes was the main variable responsible for explaining complexity in the pallet loading problem.
2021
Autores
Ferreira, AR; Ramos, AG; Silva, E;
Publicação
COMPUTATIONAL LOGISTICS (ICCL 2021)
Abstract
In the Physical Internet supply chain paradigm, modular boxes are one of the main drivers. The dimension of the modular boxes has already been subject to some studies. However, the usage of a modular approach on the container loading problem has not been accessed. In thiswork, we aim to assess the impact of modular boxes in the context of the Physical Internet on the optimization of loading solutions. A mathematical model for the CLP problem is used, and extensive computational experimentswere performed in a set of problem instances generated considering the Physical Internet concept. From this study, it was possible to conclude for the used instances that modular boxes contribute to a higher volume usage and lower computational times.
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