Navegando por Assunto "Algoritmos"

Agora exibindo 1 - 5 de 5

Algoritmos Exatos e Heurísticos para os Problemas de Steiner e de Conexão de Terminais com Número Restrito de Roteadores e Elos
(2019-07-08) Libório, Felipe Tenório de Holanda Rocha; Pinheiro, Rian Gabriel Santos; http://lattes.cnpq.br/1447954471683870; http://lattes.cnpq.br/1881833645223497
This work presents solutions for the Terminal Connection Problem with Bounded Number of Routers and Links (TCP). The TCP consists in finding a spanning tree to a subset of vertices of a given graph. It differentiates itself from the Steiner’s problem by having additional restrictions to the number of Steiner nodes allowed in a solution. The TCP can be applied in the same types of problems on which you can make use of the Steiner’s problem, which includes: VLSI circuit project; multicast routing; to model and solve telecomunications planning problems; and electricity distribution. As the TCP is a generalization on the Steiner’s problem in graphs, tests in instances of this problem were also made. Moreover, a multitude of instances of different difficulty levels was generated for the TCP, instances which posterior works on the problem will be ablem to use for comparing the performance of future solutions. The results obtained for the Steiner Problem instances were compared to those of another solution found in the literature, and the metaheuristic utilised to solve them, the Large Neighborhood Search (LNS), has shown to be viable as a simple and low cost, both in time and in memory requirements, way of reaching satisfactory results for this problem. Achieving a mean error below 2% for the evaluated instances, depending on the time given for the aolgorithm. Furthermore, this is the first known work to present a solution to the TCP. Besides the LNS metaheurístic, an exact solution was implemented by the means of the IMB ILOG CPLEX solver. For the tested instances whose optimal values were found by the presented exact solution, the LNS implementation managed to get an mean error rate of 0.66% meanwhile having a run time 22 times smaller than that of the exact solution and found the optimal value in 14 out of the 18 tried instances. The results obtained on the solving of the TCP instances, alongside the generated instances themselves, have formed a base for the comparison of future solutions that may come to be Proposed for this problem.
Análise de performance de algoritmos estocásticos aplicados ao problema do caixeiro viajante
(2024-10-09) Lima, Lucas Gabriel Oliveira Sales; Monteiro, Cleviton Vinícius Fonsêca; http://lattes.cnpq.br/9362573782715504; http://lattes.cnpq.br/7636465842833021
Optimization algorithms are increasingly relevant tools in modern companies because they are capable of optimizing processes and resources, ensuring more efficient results and timely processing for decision making. Comparing these algorithms is a common process during their adoption studies. However, the use of complex methodologies can often lead to the choice of an imprecise algorithm, since its result may not reflect the reality of a company seeking to implement applications with limited resources. In view of this problem, the need arises to evaluate these algorithms from a new perspective. The main objective of this work is to propose a reflection on the way experiments in algorithms are conducted. The present study carried out experiments with optimization algorithms using computational resources similar to those found in most companies, comparing them with another work in which optimizations and tunings were used in these same algorithms. For the experiment, the traveling salesman problem was used, through 15 benchmarking divided into 3 categories, according to the size of each article. Finally, statistical metrics were obtained for the performance of each algorithm, which, when compared to the reference article, showed shorter execution times without compromising the accuracy of the results. Probabilistic algorithms are of great financial importance to companies that need to manage resources quickly, such as airports and shipyards. Therefore, the appropriate choice of parameters provides a more accurate view of reality.
M Harmony BR: o uso de formalismos para a composição algorítmica baseada em conhecimento
(2018-02-23) Silva, Vinícius Santana; Carvalho, Tiago Buarque Assunção de; Costa Junior, Jerônimo Barbosa da; http://lattes.cnpq.br/6050271311748487; http://lattes.cnpq.br/7150833804013500; http://lattes.cnpq.br/8393251786005816
Throughout history, several studies have tried to introduce the use of computers in other areas of knowledge, including music, and several researches have been done to show the ability of computers to compose music. The present work had the objective to verify the possibility of the creation of a simple software capable of generating harmonies of a certain musical style, using context-free grammars, based on knowledge. The development of the tool was based on the analysis of the characteristics of two different musical styles: Punk Rock and Sertanejo Universitário, through the collection and analysis of data of 40 songs. Subsequently the database was expanded with the inclusion of 50 Reggae songs and 30 songs to the Sertanejo Universitário style, totaling 120 songs. Based on the information extracted from the music dataset, 3 specific grammars were generated to produce harmonies of each style analyzed by means of a composition algorithm. The study resulted in the production of an application that composes knowledge-based harmonies, which proved useful in aiding musical composition process.
Racismo algorítmico no desenvolvimento de software: um estudo de caso sobre letramento racial no ensino superior
(2024-08-05) Silva, Jamelly Nascimento; Falcão, Taciana Pontual da Rocha; Santos, George Augusto Valença; http://lattes.cnpq.br/8525564952779211; http://lattes.cnpq.br/5706959249737319
This article presents a case study on the topic of algorithmic racism in software development, focusing on racial literacy in higher education. The study involved students and instructors at the Federal Rural University of Pernambuco (Brazil) to investigate their level of knowledge about algorithmic racism. The main objective was to understand whether this knowledge is present in any way in courses related to information technology. The results reveal important insights into awareness and understanding of algorithmic racism within academia, highlighting areas of opportunity to promote more inclusive and comprehensive teaching on these crucial issues in the technology industry.
Segmentação de banhistas utilizando algoritmos de agrupamento com seleção automática do número de grupos em regiões litorâneas
(2019) Moura, Allan Alves de; Macário Filho, Valmir; http://lattes.cnpq.br/4346898674852080; http://lattes.cnpq.br/3319938637009294
The increasing number of shark attacks has been frightening people that lives in coastal areas, making it impossible to bath in certain places. In an attack situation, most of the time a course of action to save the victim’s life is only taken after the incident already has occurred, which a lifeguard tries to help her. An auxiliary tool for lifeguards was thought in order to mitigate these events and allow the lifeguards to act before the incident happens, alerting the professional if someone tries to surpass a delimited zone. The first step to bring this auxiliary tool to life is the technique of image segmentation on beach photos in search for regions that share visual similarities in order to find people inside the sea. Therefore the objective of this work is to study and find a good image segmentation algorithm capable of automatically selecting the best number of groups without the parameter control necessity. The selected algorithm will be used to implement the first phase of the lifeguard auxiliary tool in search for image regions that represent bathers. Image pre-processing techniques like beach removal were evaluated, as well as characteristics vectors selection used to compare elements. The combination between algorithms and characteristics vectors were evaluated with and without beach removal. The analyzed algorithms were: hierachical aglomerative, hierarchival divisive, X-means, auto group segmentation and automatic colored image segmentation. All of them were applied to three different characteristics vectors composed by the color system RGB (red, green and blue), LAB and the combination of RGB + LAB. The most promising result, taking into account the visual analysis and the algorithm comportamental analysis, was obtained by the automatic color image segmentation with RGB+ LAB, composed characteristics vector, with value of 1.5245 extracted from Dunn’s index, using the beach removal as post-processing technique.