Proposta de metodologia para o estudo da localização de instalações destinadas ao parqueamento de viaturas de transporte de mercadorias alimentares

O transporte rodoviário de mercadorias, embora essencial, gera custos elevados às organizações, criando a necessidade de subcontratação de empresas transportadoras. Contudo, estas também enfrentam desafios logísticos, nomeadamente no planeamento da localização de instalações. O objetivo da dissertação consiste em desenvolver uma metodologia para estudar a localização de instalações destinadas ao parqueamento de viaturas de transporte de mercadorias alimentares. A metodologia propõe a aplicação de problemas de programação linear, desenvolvidos através de alterações realizadas à formulação clássica do problema de localização simples de instalações, e integra os critérios de decisão minimax da oportunidade perdida e Hurwicz na análise da incerteza na procura. Adicionalmente, aplica a análise ABC no processo de tratamento de dados e a análise de sensibilidade dos problemas de programação linear. Devido à localização pouco estratégica da sua sede, a Transportes Paulo Duarte Lda. revelou sofrer de custos elevados resultantes de deslocações realizadas pelas viaturas vazias dos serviços de transporte de líquidos alimentares nacional (Serviço_LAS) e frigorífico internacional (Serviço_FI), tendo, por isso, constituído o objeto do presente estudo de caso. Verificou-se que a decisão que minimiza os custos totais consiste em gerir, em conjunto, as instalações já existentes na Azambuja e em Torres Vedras. Considerando os custos de deslocação dos motoristas, estima-se um custo total médio entre cenários de 348 388 € para o Serviço_LAS e 449 766 € para o Serviço_FI, aproximadamente. A metodologia proposta permitiu responder ao problema apresentado pela Transportes Paulo Duarte Ld.Road freight transport, although essential, generates high costs for organizations, creating the need for outsourcing transport companies. However, they also face logistical challenges, namely in plant location planning. The goal of the dissertation is to develop a methodology for the study of the location of facilities for the parking of food transport vehicles. The methodology proposes the application of linear programming problems, developed through changes made to the classic formulation of the uncapacitated facility location problem, and integrates the decision criteria minimax regret and Hurwicz in the analysis of demand uncertainty. In addition, it applies ABC analysis to the data processing process and analyzes the sensitivity of linear programming problems. Due to the lack of strategic location of its headquarters, Transportes Paulo Duarte Lda. revealed to suffer from high costs associated with trips made by the empty vehicles of the national food liquid transport service (Serviço_LAS) and international refrigerator service (Serviço_FI), having, therefore, constituted the object of the case study. It was found that the decision that minimizes total costs is to jointly manage the facilities that already exist in Azambuja and Torres Vedras. Considering the travel costs of the drivers, it is estimated an average total cost between scenarios of 348 388 € for the Service_LAS and 449 766 € for the Service_FI, approximately. The proposed methodology allowed to solve the problem presented by Transportes Paulo Duarte Lda

A credibility-based fuzzy location model with Hurwicz criteria for the design of distribution systems in B2C e-commerce

Facility location problem is one of the most critical elements in the design of distribution systems, and numerous studies have focused on this issue. However, facility location theory and guidelines for B2C firms are sparse. In this paper, with regard to the customer characteristics peculiar to B2C e-commerce and the turbulence of the competitive market, a new fuzzy location model is proposed to optimize the distribution system design in B2C e-commerce. The model adopts a hierarchical agglomerative clustering method to classify customers and estimate the fuzzy delivery cost. At the same time, due to the turbulence of competitive market, both market supply and customer demand are treated as fuzzy variables in the model. Afterward, the credibility measure and Hurwicz criterion are introduced to convert the model into a crisp one which has NP-hard complexity. In order to solve the crisp model, an improved genetic algorithm with particle swarm optimization is developed. Finally, the computational results of some numerical examples are used to illustrate the application and performance of the proposed model and algorithm