ABSTRACT Lettuce (Lactuca sativa) is the main leafy vegetable produced in Brazil. Since its production is widespread all over the country, lettuce traceability and quality assurance is hampered. In this study, we propose a new method to identify the geographical origin of Brazilian lettuce. The method uses a powerful data mining technique called support vector machines (SVM) applied to elemental composition and soil properties of samples analyzed. We investigated lettuce produced in São Paulo and Pernambuco, two states in the southeastern and northeastern regions in Brazil, respectively. We investigated efficiency of the SVM model by comparing its results with those achieved by traditional linear discriminant analysis (LDA). The SVM models outperformed the LDA models in the two scenarios investigated, achieving an average of 98 % prediction accuracy to discriminate lettuce from both states. A feature evaluation formula, called F–score, was used to measure the discriminative power of the variables analyzed. The soil exchangeable cation capacity, soil contents of low crystalized Al and Zn content in lettuce samples were the most relevant components for differentiation. Our results reinforce the potential of data mining and machine learning techniques to support traceability strategies and authentication of leafy vegetables.

Resumo A conclusão do curso de graduação por estudantes universitários no tempo previsto pelo currículo é desejável para os jovens e para a sociedade. O objetivo foi verificar a confiabilidade, sensibilidade e especificidade de um amplo conjunto de indicadores sobre o desempenho acadêmico de estudantes universitários, que completaram o curso de graduação dentro do tempo previsto pelo currículo, por meio de metodologia de mineração de dados, fornecida pelo algoritmo Vector Machines Suporte. Uma abordagem simples é proposta para a previsão da conclusão do curso por estudantes de uma universidade no Brasil. O conjunto de dados tem 170 alunos que concluíram o curso e 117 que não terminaram. Com a metodologia proposta, foi possível prever a conclusão do curso pelos alunos com uma precisão de 79,5% quando se utiliza as 19 variáveis originais. Uma precisão de 75% foi encontrada usando apenas cinco variáveis: curso, ano do curso, o sexo, o desempenho inicial e final acadêmico.

Abstract The conclusion of the undergraduate course by university students in the time predicted by the curriculum is desirable for young people and for society. The aim was to verify the reliability, sensitivity and specificity of a broad set of predictors for academic performance of university students, who completed the undergraduate course within the time predicted by the curricula, through data mining methodology, provided by the Support Vector Machines algorithm. A simple approach is proposed for the prediction of course completion by students in a university in Brazil. The dataset has 170 students who finished the course and 117 who did not finish. With the proposed methodology, it was possible to predict the course completion by students with an accuracy of 79.5% when using the 19 original variables. An accuracy of 75% was found using only 05 variables: Course, year of the course, gender, initial and final academic performance.

Resumen La conclusión del curso de graduación de los estudiantes universitarios en el tiempo previsto por el plan de estudios es deseable para los jóvenes y para la sociedad. El objetivo fue verificar confianza, sensibilidad y especificidad de un amplio conjunto de indicadores sobre el desempeño académico de los estudiantes universitarios, que completaron el curso de graduación dentro del tiempo previsto por los planes de estudio, a través de la metodología de minería de datos, proporcionada por el algoritmo Vector Machines Suporte. Se propone un abordaje simple para previsión de la finalización de la carrera por estudiantes en una Universidad de Brasil. El conjunto de datos tiene 170 estudiantes que concluyeron la carrera y 117 que no terminaron. Con la metodología propuesta, fue posibe prever la finalización de la carrera por los estudiantes con una precisión de 79,5% cuando se utilizan las 19 variables originales. Una precisión de 75% fue encontrada usando apenas 5 variables: Curso, duración de la carrera, sexo, desempeño inicial y final académico.