In vehicular ad hoc networks (VANets), a precise localization system is a crucial factor for several critical safety applications. The global positioning system (GPS) is commonly used to determine the vehicles’ position estimation. However, it has unwanted errors yet that can be worse in some areas, such as urban street canyons and indoor parking lots, making it inaccurate for most critical safety applications. In this work, we present a new position estimation method called cooperative vehicle localization improvement using distance information (CoVaLID), which improves GPS positions of nearby vehicles and minimize their errors through an extended Kalman filter to execute Data Fusion using GPS and distance information. Our solution also uses distance information to assess the position accuracy related to three different aspects: the number of vehicles, vehicle trajectory, and distance information error. For that purpose, we use a weighted average method to put more confidence in distance information given by neighbors closer to the target. We implement and evaluate the performance of CoVaLID using real-world data, as well as discuss the impact of different distance sensors in our proposed solution. Our results clearly show that CoVaLID is capable of reducing the GPS error by 63%, and 53% when compared to the state-of-the-art VANet location improve (VLOCI) algorithm.

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Dificuldade na aprendizagem de algoritmos é uma realidade enfrentada por estudantes de graduação da área de ciências exatas. O presente artigo investiga as causas do problema, descrevendo uma experiência que integrou ábaco, operações básicas da matemática e sistemas de numeração com o objetivo de explorar o raciocínio lógico dos estudantes e prepará-los para o estudo dos algoritmos. Foram utilizados na implementação Visualg e Free Pascal para verificar a influência do idioma do software na aprendizagem. O ambiente Moodle apoiou as discussões sobre o tema e os resultados da pesquisa apontaram avanços no desenvolvimento de algoritmos e programas de computador.

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