solutions by memetic algorithms

The Rural Postman Problem (RPP) is a particular Arc Routing Problem (ARP) which consists of determining a minimum cost circuit on a graph so that a given subset of required edges is traversed. The RPP is an NP-hard problem with significant real-life applications. This paper introduces an original approach based on Memetic Algorithms - the MARP algorithm - to solve the RPP and, also deals with an interesting Industrial Application, which focuses on the path optimization for component cutting operations. Memetic Algorithms are a class of Metaheuristics which may be seen as a population strategy that involves cooperation and competition processes between population elements and integrates “social knowledge”, using a local search procedure. The MARP algorithm is tested with different groups of instances and the results are compared with those gathered from other publications. MARP is also used in the context of various real-life applications

A Monte Carlo simulation-based approach to solve dynamic sectorization problem

In this study, two novel stochastic models are introduced to solve the dynamic sectorization problem, in which sectors are created by assigning points to service centres. The objective function of the first model is defined based on the equilibration of the distance in the sectors, while in the second one, it is based on the equilibration of the demands of the sectors. Both models impose constraints on assignments and compactness of sectors. In the problem, the coordinates of the points and their demand change over time, hence it is called a dynamic problem. A new solution method is used to solve the models, in which expected values of the coordinates of the points and their demand are assessed by using the Monte Carlo simulation. Thus, the problem is converted into a deterministic one. The linear and deterministic type of the model, which is originally non-linear is implemented in Python's Pulp library and in this way the generated benchmarks are solved. Information about how benchmarks are derived and the obtained solutions are presented.info:eu-repo/semantics/publishedVersio

A new model for location-allocation problem based on sectorization

Many models have been proposed for the location-allocation problem. In this study, based on sectorization concept, we propose a new single-objective model of this problem, in which, there is a set of customers to be assigned to distribution centres (DCs). In sectorization problems there are two important criteria as compactness and equilibrium, which can be defined as constraints as well as objective functions. In this study, the objective function is defined based on the equilibrium of distances in sectors. The concept of compactness is closely related to the accessibility of customers from DCs. As a new approach, instead of compactness, we define the accessibility of customers from DCs based on the covering radius concept. The interpretation of this definition in real life is explained. As another contribution, in the model, a method is used for the selection of DCs, and a comparison is made with another method from the literature, then the advantages of each are discussed. We generate benchmarks for the problem and we solve it with a solver available in Python’s Pulp library. Implemented codes are presented in brief.info:eu-repo/semantics/publishedVersio

Reel and sheet cutting at a paper mill

This work describes a real-world industrial problem of production planning and cutting optimization of reels and sheets, occurring at a Portuguese paper mill. It will focus on a particular module of the global problem, which is concerned with the determination of the width combinations of the items involved in the planning process: the main goal consists in satisfying an order set of reels and sheets that must be cut from master reels. The width combination process will determine the quantity/weight of the master reels to be produced and their cutting patterns, in order to minimize waste, while satisfying production orders. A two-phase approach has been devised, naturally dependent on the technological process involved. Details of the models and solution methods are presented. Moreover some illustrative computational results are included

Cutting path as a Rural Postman Problem: solutions by Memetic Algorithms

The Rural Postman Problem (RPP) is a particular Arc Routing Problem (ARP) which consistsof determining a minimum cost circuit on a graph so that a given subset of required edges is traversed. TheRPP is an NP-hard problem with significant real-life applications. This paper introduces an originalapproach based on Memetic Algorithms - the MARP algorithm - to solve the RPP and, also deals with aninteresting Industrial Application, which focuses on the path optimization for component cuttingoperations. Memetic Algorithms are a class of Metaheuristics which may be seen as a population strategythat involves cooperation and competition processes between population elements and integrates "socialknowledge", using a local search procedure. The MARP algorithm is tested with different groups ofinstances and the results are compared with those gathered from other publications. MARP is also used inthe context of various real-life applications

Influence of distance and illumination on detection of marks in augmented reality applied to transcranial magnetic stimulation

O estudo foi levado a cabo durante o desenvolvimento de uma aplicação móvel de Realidade Aumentada que representa modelos virtuais 3D do cérebro de um paciente sobre a imagem real da sua cabeça. O objetivo principal da aplicação é guiar os médicos no uso de uma terapia médica não invasiva, designada por Estimulação Magnética Transcraniana, que utiliza estímulos eletromagnéticos para tratar problemas neurológicos. O rastreio destas marcas provou ser um dos desafios principais da aplicação implementada e observámos que as condições luminosas e a distância às marcas são dois dos fatores principais que podem influenciar a sua deteção com precisão.The study was carried out while developing an Augmented Reality mobile application that represents 3D virtual models of the brain of a patient over the real image of the patient’s head. The main purpose of the application is to guide doctors during a non-invasive medical procedure called Transcranial Magnetic Stimulation that uses electromagnetic stimulation to treat neurological problems. The tracking of these markers have proven to be one of the more challenging components of such an application and we observe that lighting conditions and distance to the markers are two of the main factors that can influence their accurate recognition.info:eu-repo/semantics/publishedVersio

Provas de avaliação de Investigação Operacional : enunciados e resoluções: 1998/1999 a 2001/2002

Paviot Jacques. Statuts inédits de l'ordre de la Toison d'or. In: Bulletin de la Société Nationale des Antiquaires de France, 1999, 2002. pp. 79-80