Navegando por Assunto "Linear programming"

Agora exibindo 1 - 4 de 4

Acesso aberto (Open Access)
Análise de alternativas intermodais para escoar a produção de soja dos Estados do Pará e Tocantins
(Universidade Federal do Pará, 2021-08-31) OLIVEIRA, Vitor Hugo Pereira de; ROCHA, Marcus Pinto da Costa da; http://lattes.cnpq.br/7169569605967930; TOBIAS, Maisa Sales Gama; http://lattes.cnpq.br/9635266655242384
World projections indicate an increase in demand for soy and, in this context, countries with continental dimensions and favorable soils such as Brazil stand out. Particularly, the states of the northern region of Brazil show themselves as possible new agricultural frontiers for this crop. However, they need to be competitive in order to sell their production, which indicates the need for studies of available modal alternatives to determine those with better economic results. With this in mind, the present work executed the analysis of alternative intermodal routes using linear programming, to identify the optimal solution route, in support to decision-making in the transport of soybeans for export, taking as a case a region located between States of Pará and Tocantins, close to the Araguaia-Tocantins waterway. Within the categories of linear programming models, the particular case called transport and transshipment problem was used. The model aimed to minimize transport costs from the production centers to the exporting port, through the current infrastructure and, under different scenarios of intermodal alternatives formed by the project of Ferrovia Paraense S.A. and by Araguaia-Tocantins waterway, the year 2019 and production projections are considered for the year 2029. The results showed that the scenarios with waterway transport bring greater benefit to the region, achieving savings of up to 23%. Furthermore, the Vila do Conde port complex expands its zone of influence, thus obtaining increase in the quantity exported in up to 1059.7%. As well, it confirms that the State of Pará is the one that most needs an intermodal alternative. Furthermore, the routes were configured in new transport networks, reducing the distances traveled in the road modal to transport production from the municipalities, reducing the flow on the main highways. Thus, it is concluded that intermodal transport improves regional competitiveness and favors the development of States.
Acesso aberto (Open Access)
Compressão tempo-custo paramétrica ótima de projetos de construção civil
(Universidade Federal do Pará, 2012-08-30) BENTES, Jayme; ICHIHARA, Jorge de Araújo; http://lattes.cnpq.br/5726366418302065
One of the issues of the Civil Construction Industry is around the planning phase of the the project, when is possible to verify the difficulty in completing the project in time, initially, thinking as the contractor. Therefore, the present study proposes the application of the linear programming method as a solution to the problem of the optimization of the factors time and costs from the Civil Construction projects. Initially it was done, by bibliographic mapping, also as the re-reading of some basic concepts, programming Technics with network and critical path. Afterword, it was discussed definitions of operational research and mathematical models of Linear Programming. It was proposed, therefore, a method aiming the solution of the issue of the time optimization and projects expenses of Civil Construction. To demonstrate the application of the proposed method, it was used as a scenario, a governmental construction project, that the goal was the compression of the project in 14 days, reaching a period of contract, a cost of compression the amount of R$ 95,040.15 (ninety five thousand forty dollars and fifteen cents), less than if there were an increase in penalty for delay. With this achieved our objective, compression project for the desired duration.
Acesso aberto (Open Access)
Programação Linear aplicada no Transporte Aquaviário de passageiros sob restrições de demanda e nível de serviço para as travessias Belém-Camará, Belém-Arapari e Belém-Cotijuba
(Universidade Federal do Pará, 2022-12-22) ALENCAR, Elisangela da Silva dos Santos de; ROCHA, Marcus Pinto da Costa da; http://lattes.cnpq.br/7169569605967930; https://orcid.org/0000-0002-1849-1982; TOBIAS, Maisa Sales Gama; http://lattes.cnpq.br/9635266655242384; https://orcid.org/0000-0002-0888-0685
In the Amazon region, hydrological transportation has historically played a crucial role. However, passenger water transportation lacks economic models that assist in the design and implementation of strategies for its viability. In this study, a cost model for passenger water transportation was developed based on activity-based costing principles and linear programming. The aim was to optimize costs and maximize profits, considering demand and service level constraints in a water transportation company in the city of Belém, Brazil. The model was applied to three crossings that operate passenger, cargo, and vehicle trips between Belém and Ilha de Marajó. Various simulations were conducted to explore opportunities and conditions for reducing operational costs. The objective was to find the best cost-profit relationship, with the model parameters including variable costs, profits, and the maximum number of possible trips. Based on the results, alternative cost reduction strategies were established to achieve maximum profit and the highest number of trips. The model proved to be useful through the analysis of viable and effective cost reduction strategies
Acesso aberto (Open Access)
Projeto de um controlador amortecedor robusto aplicado a um sistema de potência sujeito a incertezas paramétricas
(Universidade Federal do Pará, 2016-03-16) CUNHA, Leiliane Borges; BARRA JUNIOR, Walter; http://lattes.cnpq.br/0492699174212608
This work presents the design of a Stabilizer for the damping of the electromechanical oscillations in electric power systems using robust control technical based on affine parametric uncertainties. These systems are represented by models that have uncertainties in yours parameters, relating to changes in operating conditions. The project methodology is structured to provide a stabilizer that provides the maximum damping to the system, specified by a polytope of characteristic polynomials. For this, it is used poles robust allocation techniques and Chebyshev's theorem, integrated into the solution of linear programming techniques, for the controller design. This technique allows incorporating restrictions on system performance, corresponding to the uncertainties present in the system, making the controller design more robust. Comparisons of the robust controller with a classic controller are made in order to evaluate the results and validate the advantages of the use of controllers designed by the technique proposal. The results and comparisons are performed in simulation environments using MATLAB / SIMULINK software, which allows to model and simulate all kinds of dynamic systems.