Napoleao Nepomuceno

Universidade de Fortaleza · Department of Computer Science

The ever-increasing need for stable, seamless, high-speed connectivity places an enormous burden on the communications infrastructure, comprised of access, backhaul, and core networks. Furthermore, recent advances in access technologies shift the capacity bottleneck towards the newly popularized wireless backhaul network, which is also susceptible...

The Cutting Stock Problem (CSP) is an optimisation problem that roughly consists of cutting large objects in order to produce small items. The computational effort for solving this problem is largely affected by the number of cutting patterns. In this article, in order to cope with large instances of the One-Dimensional Cutting Stock Problem (1D-CS...

RESUMO Neste trabalho, investiga-se o problema de realocação de passageiros de voos cancelados em virtude do fechamento de um aeroporto de trânsito, uma situação de contingência bastante atual em face à pandemia de Covid-19. Um modelo em Programação Linear Inteira é proposto para que a companhia aérea afetada possa minimizar uma função que consider...

RESUMO Uma técnica de geração de padrões para o Problema de Corte de Estoque unidimensional é proposta, além de uma estratégia para restringir o número de padrões gerados, tornando tratáveis instâncias de grande porte. Resultados computacionais são apresentados para um modelo em Programação Linear Inteira (PLI), uma implementação da técnica de Gera...

RESUMO Neste artigo, nós consideramos um problema que surge no projeto de linhas aéreas de transmissão de energia. Particularmente, nós estamos interessados em decidir a distribuição de cabos condutores com o intuito de diminuir o número de emendas necessárias. Na verdade, cabos condutores em geral são fornecidos em padrões de bobinas cujos comprim...

Resumo: O PRESENTE TRABALHO SUGERE UM PROCESSO SUPORTADO POR UM SOFTWARE PARA O PLANEJAMENTO DA DEMANDA POR VENDAS EM EMPRESAS QUE ATUAM EM CENÁRIOS DINÂMICOS. O MÉTODO UTILIZADO COMBINA DADOS QUANTITATIVOS, ORIUNDOS DE MÉTODOS ESTATÍSTICOS, E INFORMAÇÕES QUALITATIVAS, ORIUNDAS DAS ÁREAS FUNCIONAIS DA ORGANIZAÇÃO E DO RESPECTIVO MERCADO NO QUAL A O...

In this work, we evaluate the use of the Generate-and-Solve methodology to tackle the Minimum Covering Arborescence Problem using Simulated Annealing and Genetic Algorithm me-taheuristics. Generate-and-Solve is a hybrid methodology for dealing with difficult combinatorial optimization problems, artificially reducing the search space for solutions....

In this paper, we investigate a university classroom assignment problem, using an Integer Linear Programming model to solve it. The problem consists of assigning all courses in such a way to avoid that two courses are assigned to the same classroom at the same time. Considering the current allocation in use by the institution, the focus of this pro...

Ant Colony Optimization is a populational metaheuristic based on the behavior of real ants. As this metaheuristic is based on a population of relatively independent agents, there is ample space for many parallelization models in different computer architectures. With the spread of consumer-grade shared memory multicore processors, it's important to...

In the vehicle routing problem with simultaneous pickup and delivery (VRPSPD), customers demanding both delivery and pickup operations have to be visited once by a single vehicle. In this work, we propose a fast randomized algorithm using a nearest neighbor strategy to tackle an extension of the VRPSPD in which the fleet of vehicles is heterogeneou...

We propose in this paper a two-phase approach that decomposes the process of solving the three-dimensional single Container Loading Problem (CLP) into subsequent tasks: (i) the generation of blocks of boxes and (ii) the loading of blocks into the container. The first phase is deterministic, and it is performed by means of constructive algorithms fr...

Routing is a strategy that aims to find the best sequence or route to be performed by vehicles, reducing logistics costs and meeting a series of requirements according to the application at hand. In this work, we seek to optimize the routes for collecting solid waste in a company which provides environmental services in the city of Fortaleza. We pr...

ABSTRACT Cost-effective planning and dimensioning of backhaul microwave networks under unreliable channel conditions remains a relatively underexplored area in the literature. In particular, bandwidth assignment requires special attention as the transport capacity of microwave links is prone to variations due to, e.g., weather conditions. In this p...

In this work, we study an optimization problem known as the Curriculum-based Course Timetabling, which consists in determining the weekly assignment of disciplines in timeslots and the allocation of disciplines to lecturers, according to their availability and competences. A number of technical, pedagogical, and legal constraints must be considered...

In this paper, we propose an Integer Linear Programming model to solve the Crew Scheduling Problem in urban bus transportation. Due to the difficulty of hiring qualified drivers, we aim at minimizing the total number of employees used in the scheduling, respecting both legal constraints and cultural restrictions imposed by the public transportation...

We aim at dimensioning fixed broadband microwave wireless networks under unreliable channel conditions. As the transport capacity of microwave links is prone to variations due to, e.g., weather conditions, such a dimensioning requires special attention. It can be formulated as the determination of the minimum cost bandwidth assignment of the links...

The three-dimensional multiple bin packing problem (3D-MBPP) consists of packing a set of items into a number of bins with different dimensions so as to optimize a given objective function, e.g., minimize the number of bins used to pack the items. In this paper, we consider a real world 3D-MBPP with several cargo constraints that arises from an aut...

In this paper, we extend our former investigation on conceiving reliable fixed point-to-point wireless networks under outage probability constraints. We consider the problem of determining the minimum cost bandwidth assignment of a network, while guaranteeing a reliability level of the solution. If the optimal bandwidth assignment and routing of tr...

Este artigo apresenta um algoritmo híbrido baseado em construção de blocos para resolver o Problema de Carregamento de Contêiner. A ideia central do algoritmo é decompor esse clássico Problema de Corte e Empacotamento em dois subproblemas: um problema de empacotamento tridimensional que objetiva gerar blocos de caixas; e um problema de posicionamen...

We consider an integrated biomass inventory and energy production problem that arises from scenario analysis in national energy planning. It addresses together two decision stages that have previously been kept distinct: the decisions on the purchase of biomass and the decisions on the production of electricity and heat of each power plant. We mode...

The Generate-and-Solve is a hybrid framework to cope with hard combinatorial optimization problems by artificially reducing the search space of solutions. In this framework, a metaheuristic engine works as a generator of reduced instances of the problem. These instances, in turn, can be more easily handled by an exact solver to provide a feasible (...

We consider a variant of the graph searching games that is closely related to the routing reconfiguration problem in WDM networks. In the digraph processing game, a team of agents is aiming at clearing, or processing, the vertices of a digraph D. In this game, two important measures arise: 1) the total number of agents used, and 2) the total number...

In this paper, we investigate on conceiving reliable fixed broadband wireless networks under outage probability constraints. We introduce a joint model of data routing and bandwidth assignment that minimizes the total renewal fees of licenses. This problem differs from classical capacity planning since the capacity of microwave links is prone to va...

In this paper, we propose a chance-constrained mathematical program for fixed broadband wireless networks under unreliable channel conditions. The model is reformulated as an integer linear program and valid inequalities are derived for the corresponding polytope. Computational results show that by an exact separation approach the optimality gap is...

In this paper, we present a mathematical formulation for saving energy in fixed broadband wireless networks by selectively turning off idle communication devices in low-demand scenarios. This problem relies on a fixed-charge capacitated network design (FCCND), which is very hard to optimize. We then propose heuristic algorithms to produce feasible...

Cette thèse a été développée en co-tutelle entre l'Université de Nice-Sophia Antipolis et l'Université Federale du Ceará.

We consider a variant of the graph searching games that models the routing reconfiguration problem in WDM networks. In the digraph processing game, a team of agents aims at processing, or clearing, the vertices of a digraph D. We are interested in two different measures: (1) the total number of agents used, and (2) the total number of vertices occu...

In this work, we investigate on determining feasible radio configurations in fixed broadband wireless networks, focusing on power efficiency. Under this scenario, a power-efficient configuration can be characterized by a modulation constellation size and a transmission power level. Every link holds a set of power-efficient configurations, each of t...

Nous étudions le problème du reroutage d'un ensemble de connexion dans un réseau. Il consiste à passer d'un routage initial (ensemble de chemins reliant des paires de noeuds) à un autre, en traitant séquentiellement chaque connexion. Il est parfois indispensable d'en interrompre temporairement certaines au cours du processus de reconfiguration, ce...

Nous étudions la minimisation de la consommation d'énergie des réseaux sans-fil fixes à transmission par liens microondes, par l'optimisation jointe du routage des flux de données et la sélection de la configuration des liens. Nous présentons une formulation mathématique exacte basée sur un multiflot entier de coût minimum avec des fonctions de coû...

In this report, we study the problem of rerouting a set of lightpaths in WDM networks. The reconfiguration issue arises for instance when it is necessary to improve the usage of resources or when a maintenance operation is planned on a particular link of the network. In order to avoid service interruptions, old lightpaths should not be torn down be...

This work presents a hybrid optimization framework for tackling cutting and packing problems, which is based upon a particular combination scheme between heuristic and exact methods. A metaheuristic engine works as a generator of reduced instances for the original optimization problem, which are formulated as mathematical programming models. These...

This paper presents a scalability analysis over a novel integer programming model devoted to optimize power consumption efficiency in heterogeneous wireless sensor networks. This model is based upon a schedule of sensor allocation plans in multiple time intervals subject to coverage and connectivity constraints. By turning off a specific set of red...

In this work, we investigate on minimizing the energy consumption of a wireless backhaul communication network through a joint optimization of data routing and radio configuration. The backhaul network is modeled by a digraph in which the nodes represent radio base stations and the arcs denote radio links. According to the scenario under considerat...

This paper presents a novel hybrid approach for solving the Container Loading (CL) problem based on the combination of Integer Linear Programming (ILP) and Genetic Algorithms (GAs). More precisely, a GA engine works as a generator of reduced instances for the original CL problem, which are formulated as ILP models. These instances, in turn, are sol...

This paper presents a novel hybrid approach for solving the Container Loading (CL) problem based on the combination of Integer Linear Programming (ILP) and Genetic Algorithms (GAs). More precisely, a GA engine works as a generator of reduced instances for the original CL problem, which are formulated as ILP models. These instances, in turn, are sol...

RESUMO Este artigo apresenta uma metodologia híbrida, combinando Metaheurística e Programação Linear Inteira, para resolver o Problema de Carregamento de Contêiner. Um algoritmo genético atua como um gerador de instâncias reduzidas do problema original, descritas em Programação Matemática. As instâncias geradas são resolvidas, fornecendo os valores...

This paper presents a hybrid framework for coping with hard combinatorial optimization problems, which is based upon a methodology combining heuristic and exact methods. In this framework, a metaheuristic engine works as a generator of reduced instances for the problem, which are formulated as mathematical programming models. These instances, in tu...