Giovanni Santos - Academia.edu (original) (raw)
Papers by Giovanni Santos
15 16 17 Ore mining is among the most environmentally destructive anthropogenic practices, 18 par... more 15 16 17 Ore mining is among the most environmentally destructive anthropogenic practices, 18 particularly in developing countries. Correct assessment of its impacts on soil ecosystems 19 requires an understanding of the response of soil food webs. Nematodes, often the most 20 abundant invertebrates in soils, occupy various positions in food webs, and their assemblages 21 are commonly used to reflect soil health. In October 2014, we collected soil samples from five 22 sites of a small-scale mining area in Sibutad, southern Philippines, to assess the influence of 23 mining activities on nematode assemblages. Two sites were considered undisturbed as there 24 were no visible signs of mining, while the other three sites were disturbed. Nematodes were 25 extracted live and identified to genus level using morphology-based identification. We 26 analysed genus composition, genus and trophic diversity, and the life-history based maturity 27 index. We measured soil environmental variables (pH...
Lavoura arcaica, romance do escritor brasileiro Raduan Nassar, revela clara intertextualidade com... more Lavoura arcaica, romance do escritor brasileiro Raduan Nassar, revela clara intertextualidade com o texto biblico, evidenciada em relacoes intertextuais tanto de captacao quanto de subversao. Esses intertextos diversos dao origem a dois discursos fundamentais em oposicao, que encenam o grande embate social entre as vozes da autoridade e da contestacao. O discurso sapiencial e solene do pai, imitacao da Biblia, e questionado e carnavalizado pela voz subversiva e "endemoninhada" do filho-narrador, Andre. Nesta sua fala, encontra-se instalado um "demonio literario" que poe em transe a linguagem nos seus diversos niveis. Realiza-se aqui uma leitura do romance de Nassar que permita contempla-lo nao apenas como um palimpsesto biblico em estado de possessao demoniaca, mas tambem como uma polifonia dissonante e violenta. Tal leitura sera potencializada levando-se em conta as categorias da teoria do romance de Mikhail Bakthin Abstract
The initial learning of algorithms becomes harder when the programming language used has keywords... more The initial learning of algorithms becomes harder when the programming language used has keywords in a foreign language not known by the student. The purpose of this study is to analyze the use of the learner's native language when starting to learn to program. A questionnaire was applied at the end of four consecutive semesters of an introductory programming course, and five questions were selected to identify the level of student satisfaction and the efficiency of the educational process. The results obtained show that most of the students interviewed were satisfied, had their expectations met and recommended the methodology used. Resumo. O aprendizado inicial de algoritmos se torna mais árduo quando a linguagem de programação utilizada possui comandos em uma língua estrangeira não dominada pelo aluno. O propósito deste estudo é analisar o uso da linguagem nativa do aprendiz nos estudos iniciais de programação. Um questionário foi aplicado ao final de quatro semestres consecut...
Educational Data Mining (EDM) is the research area concerned with the use of data mining methods ... more Educational Data Mining (EDM) is the research area concerned with the use of data mining methods and its development in order to explore data sets collected in educational platforms. EDM has a considerable potential to improve the education quality. In this paper, we first model the Moodle variables of the Brazilian National School of Public Administration (Enap) database. Next we apply EDM to understand the standard Moodle variables influence and the proposed variables in the attendees performance and dropout rates. Our framework includes the following data mining approaches: decision tree, Adaboost based decision tree, random forest and k-means. The obtained Adaboost based decision tree outperforms the other approaches and the state-of-the-art framework with 91 % of Precision, 89 % of Recall and 90 % of F1 score in terms of the attendees performance evaluation.
Ore mineral extraction involves stripping of topsoils that can lead to eradication of soil biota,... more Ore mineral extraction involves stripping of topsoils that can lead to eradication of soil biota, including nematodes. Hence, rehabilitation is needed to assist in the recovery of damaged soil ecosystems. In many developing countries, e.g., the Philippines, rehabilitation of soils is mostly carried out through addition of organic amendments and development of aboveground vegetation. Rehabilitation success is often judged based on the survival or growth rate of plants, (e.g., Acacia sp.). This may not be sufficient since tree species used for rehabilitation can tolerate harsh soil conditions. In the present study, we instead examined the response of soil nematodes that are often considered the most abundant soil taxa and play important roles in soil functioning. We assessed the re-establishment of nematode communities in ‘rehabilitated’ areas between 8 and 13 years after the onset of their rehabilitation by comparing nematode community descriptors (e.g., abundance, evenness and diver...
More than 90% of traffic accidents are caused by humans. Therefore, the wide adoption of autonomo... more More than 90% of traffic accidents are caused by humans. Therefore, the wide adoption of autonomous vehicles and advanced driver assistance systems (ADAS) is expected to save hundreds of thousands of lives in the next decades. One important capability of autonomous vehicles and ADAS is pedestrian detection. However, such detection becomes very challenging in scenarios where pedestrians are partially occluded, resulting in high rates of non-detection. In this paper, we improve the performance of a pedestrian classifier by proposing frameworks composed of Histogram of Oriented Gradients (HOG) feature extraction, combined with Support Vector Machine (SVM), and eXtreme Gradient Boosting (XGBoost) learning models. In order to validate the performance of the improved approach, we consider the PSU and the INRIA pedestrian datasets. The state-of-the-art detection rates for the PSU and INRIA datasets are 55% and 54%, respectively. The proposed approach achieves detection rates of 86% and 82%...
Accurate prediction of the biodiversity–ecosystem functioning relationship requires adequate unde... more Accurate prediction of the biodiversity–ecosystem functioning relationship requires adequate understanding of the interactions among species in a community. Effects of species diversity on ecosystem functioning are usually considered more pronounced with increasing functional dissimilarity, although species within functional groups may also perform non-identical functions and interact with each other. Here we present results of a laboratory experimental study aimed at elucidating whether interspecific interactions among species within a single nematode trophic group, bacterivores, (1) affect population development and community structure, and (2) depend on food availability. We studied the population growth of Rhabditis (Pellioditis) marina, a rhabditid nematode known to favour very high food densities when in monoculture, and of Diplolaimelloides meyli and D. oschei, congeneric Monhysteridae known to perform better in monocultures at intermediate food availability. Both Diplolaimel...
This paper presents the scenario of the Engineering courses of the Faculty UnB Gama (FGA) in rela... more This paper presents the scenario of the Engineering courses of the Faculty UnB Gama (FGA) in relation to the number of male newcomers versus the number of female ones. It is possible to see, through analysis of the data collected, that the number of male students is much higher than that of female ones, from the creation of the campus in the second semester of 2008 until now. This occurs despite FGAs efforts in promoting the Engineering courses on campus using an experimental laboratory, through the Girls in Computing Program, supported by the National Council of Scientific and Technologic Development (CNPq), in partnership with the high schools of the region. Lectures are also conducted, focused on the female public, and looking do debunk the idea that Engineering is a typically male-oriented course, and trying to awaken the vocational interest of women towards Engineering. Through the surveys focused in the low rate of women in engineering courses, some things come up: (1) the lac...
This Research Full Paper studies the impact of using Calango language in the introductory learnin... more This Research Full Paper studies the impact of using Calango language in the introductory learning of algorithms and computer programming by Brazilian engineering undergraduates. Calango is an educational multi-platform tool designed to facilitate algorithm learning and provide a simple syntax that enables developing advanced logic, so that students concentrate on logic without worrying about language details, considering its based on Portuguese pseudocode commands. A survey was conducted to evaluate if the teaching methods and tools used in the engineering introductory computer programming course were helpful. The questionnaire was applied at the end of four consecutive semesters of lecturing the course, and five questions were selected to analyze Calango’s influence in the learning process. Approximately 95% of the participants agreed that Calango should continue in the class. Students reported that the learning of C language was more accessible due to the initial contact with Cal...
To meet socio-cultural demands imposed by the new millennium and its implications for education, ... more To meet socio-cultural demands imposed by the new millennium and its implications for education, it was necessary for teachers and students to participate actively in the teaching-learning process. In this context, the classes' evaluation by students has been a tool widely used in various universities in different countries. For institutions and teachers, these assessments allow knowing and measuring the results, further analysis of the institutional status, reviewing projects, adjusting goals, diagnosing weaknesses and correcting possible deviations. For the monitoring and improvement of this process, it was necessary to create instruments that aimed to evaluate the performance of the proposed changes. The teaching-learning methodology adopted in the Introduction to Computer Science classes may be a process that makes it difficult to understand the principles of language programming for undergraduate students in Computer Science and related areas, generating high failure and co...
Autonomous vehicles may save 500.000 lives between 2035 and 2045, since humans cause more than 90... more Autonomous vehicles may save 500.000 lives between 2035 and 2045, since humans cause more than 90% of traffic accidents. In order to have an accurate perception of the environment and to avoid accidents, autonomous vehicles require a positioning estimation with only a few centimeters errors. Therefore, state-of-the-art third generation GNSS systems are not suitable for autonomous vehicle applications. In this paper, we propose an improved localization framework for autonomous vehicles via tensor and antenna array based GNSS receiver. As shown in this paper, in challenging urban scenarios, antenna array based GNSS receivers using tensor based algorithms can provide a positioning five times more accurante than state-of-the-art single antenna based GNSS receivers, reducing the positioning error from 149 cm to 30 cm.
Materials Research
The aim of this paper was to determine the influence of machining parameters on the surface layer... more The aim of this paper was to determine the influence of machining parameters on the surface layer, and consequently on the electrochemical properties, of ASTM F138 austenitic stainless steels. Eight different surface conditions were generated in cylindrical samples by turning and polishing. The surface was characterized by surface roughness R a and R t , Vickers microhardness and microstructural characteristics. Cyclic voltammetric tests were performed to evaluate the potential of repassivation and pitting. The surfaces were analyzed by Scanning Electron Microscopy after the electrochemical tests were performed. The cutting parameters were identified to have a significant influence, and the feed rate was as influential as the depth of cut. The use of polishing alone is not sufficient to ensure that a surface has good surface integrity. Even with the polishing application, usually used to produce prostheses, a significant reduction in corrosion resistance occurs if care is not taken to minimize surface machining damage. Corrosion resistance is lower and pitting nucleation is higher in the samples with no polishing and with more severe machining parameters. The tests indicated that softer machining parameters can contribute to an increase in the life of implantable components, reducing the probability of localized corrosion, as well as improving the mechanical properties of prostheses.
Brazilian Journal of Health Review
RESUMO O Hipercortisolismo Subclínico (HS) é uma condição de difícil diagnóstico e está presente ... more RESUMO O Hipercortisolismo Subclínico (HS) é uma condição de difícil diagnóstico e está presente em até 30% dos casos de Incidentaloma Adrenal (IA). O hipercortisolismo em um nível sutil e prolongado tem diversas consequências, tendo como comorbidades associadas mais frequentes a hipertensão arterial sistêmica (HAS), a diabetes mellitus do tipo 2 (DM2), a osteoporose, dislipidemia, a obesidade, doenças cardiovasculares e desequilíbrio no sistema músculo-esquelético. O diagnóstico ainda carece de um padrão ouro e diverge quanto as diversas diretrizes das sociedades de endocrinologia, porém o teste que tem se mostrado mais eficiente é o teste de supressão com 1mg de dexametasona (TSD), que deve ser acompanhado de outros testes de confirmação, que dependem da recomendação da diretriz analisada, os quais podem incluir o cortisol salivar noturno (CSN), o cortisol livre urinário de 24 horas (CLU), os níveis de ACTH e os níveis de sulfato de dehidroepiandrosterona (DHEAS), além de outros testes. O tratamento será decidido entre a intervenção cirúrgica ou pelo tratamento conservador. A decisão quanto o tratamento também não está em consenso na literatura, visto que existe a necessidade de evidências de mais alto nível, entretanto, estudos analisados parecem consentir para um bom prognóstico no que tange a intervenção cirúrgica em detrimento da terapia conservadora, a qual raramente mostra-se benéfica e pode apresentar, inclusive, piora do estado e comorbidades associadas ao HS.
Proceedings of the XXXIII Brazilian Symposium on Software Engineering
15 16 17 Ore mining is among the most environmentally destructive anthropogenic practices, 18 par... more 15 16 17 Ore mining is among the most environmentally destructive anthropogenic practices, 18 particularly in developing countries. Correct assessment of its impacts on soil ecosystems 19 requires an understanding of the response of soil food webs. Nematodes, often the most 20 abundant invertebrates in soils, occupy various positions in food webs, and their assemblages 21 are commonly used to reflect soil health. In October 2014, we collected soil samples from five 22 sites of a small-scale mining area in Sibutad, southern Philippines, to assess the influence of 23 mining activities on nematode assemblages. Two sites were considered undisturbed as there 24 were no visible signs of mining, while the other three sites were disturbed. Nematodes were 25 extracted live and identified to genus level using morphology-based identification. We 26 analysed genus composition, genus and trophic diversity, and the life-history based maturity 27 index. We measured soil environmental variables (pH...
Lavoura arcaica, romance do escritor brasileiro Raduan Nassar, revela clara intertextualidade com... more Lavoura arcaica, romance do escritor brasileiro Raduan Nassar, revela clara intertextualidade com o texto biblico, evidenciada em relacoes intertextuais tanto de captacao quanto de subversao. Esses intertextos diversos dao origem a dois discursos fundamentais em oposicao, que encenam o grande embate social entre as vozes da autoridade e da contestacao. O discurso sapiencial e solene do pai, imitacao da Biblia, e questionado e carnavalizado pela voz subversiva e "endemoninhada" do filho-narrador, Andre. Nesta sua fala, encontra-se instalado um "demonio literario" que poe em transe a linguagem nos seus diversos niveis. Realiza-se aqui uma leitura do romance de Nassar que permita contempla-lo nao apenas como um palimpsesto biblico em estado de possessao demoniaca, mas tambem como uma polifonia dissonante e violenta. Tal leitura sera potencializada levando-se em conta as categorias da teoria do romance de Mikhail Bakthin Abstract
The initial learning of algorithms becomes harder when the programming language used has keywords... more The initial learning of algorithms becomes harder when the programming language used has keywords in a foreign language not known by the student. The purpose of this study is to analyze the use of the learner's native language when starting to learn to program. A questionnaire was applied at the end of four consecutive semesters of an introductory programming course, and five questions were selected to identify the level of student satisfaction and the efficiency of the educational process. The results obtained show that most of the students interviewed were satisfied, had their expectations met and recommended the methodology used. Resumo. O aprendizado inicial de algoritmos se torna mais árduo quando a linguagem de programação utilizada possui comandos em uma língua estrangeira não dominada pelo aluno. O propósito deste estudo é analisar o uso da linguagem nativa do aprendiz nos estudos iniciais de programação. Um questionário foi aplicado ao final de quatro semestres consecut...
Educational Data Mining (EDM) is the research area concerned with the use of data mining methods ... more Educational Data Mining (EDM) is the research area concerned with the use of data mining methods and its development in order to explore data sets collected in educational platforms. EDM has a considerable potential to improve the education quality. In this paper, we first model the Moodle variables of the Brazilian National School of Public Administration (Enap) database. Next we apply EDM to understand the standard Moodle variables influence and the proposed variables in the attendees performance and dropout rates. Our framework includes the following data mining approaches: decision tree, Adaboost based decision tree, random forest and k-means. The obtained Adaboost based decision tree outperforms the other approaches and the state-of-the-art framework with 91 % of Precision, 89 % of Recall and 90 % of F1 score in terms of the attendees performance evaluation.
Ore mineral extraction involves stripping of topsoils that can lead to eradication of soil biota,... more Ore mineral extraction involves stripping of topsoils that can lead to eradication of soil biota, including nematodes. Hence, rehabilitation is needed to assist in the recovery of damaged soil ecosystems. In many developing countries, e.g., the Philippines, rehabilitation of soils is mostly carried out through addition of organic amendments and development of aboveground vegetation. Rehabilitation success is often judged based on the survival or growth rate of plants, (e.g., Acacia sp.). This may not be sufficient since tree species used for rehabilitation can tolerate harsh soil conditions. In the present study, we instead examined the response of soil nematodes that are often considered the most abundant soil taxa and play important roles in soil functioning. We assessed the re-establishment of nematode communities in ‘rehabilitated’ areas between 8 and 13 years after the onset of their rehabilitation by comparing nematode community descriptors (e.g., abundance, evenness and diver...
More than 90% of traffic accidents are caused by humans. Therefore, the wide adoption of autonomo... more More than 90% of traffic accidents are caused by humans. Therefore, the wide adoption of autonomous vehicles and advanced driver assistance systems (ADAS) is expected to save hundreds of thousands of lives in the next decades. One important capability of autonomous vehicles and ADAS is pedestrian detection. However, such detection becomes very challenging in scenarios where pedestrians are partially occluded, resulting in high rates of non-detection. In this paper, we improve the performance of a pedestrian classifier by proposing frameworks composed of Histogram of Oriented Gradients (HOG) feature extraction, combined with Support Vector Machine (SVM), and eXtreme Gradient Boosting (XGBoost) learning models. In order to validate the performance of the improved approach, we consider the PSU and the INRIA pedestrian datasets. The state-of-the-art detection rates for the PSU and INRIA datasets are 55% and 54%, respectively. The proposed approach achieves detection rates of 86% and 82%...
Accurate prediction of the biodiversity–ecosystem functioning relationship requires adequate unde... more Accurate prediction of the biodiversity–ecosystem functioning relationship requires adequate understanding of the interactions among species in a community. Effects of species diversity on ecosystem functioning are usually considered more pronounced with increasing functional dissimilarity, although species within functional groups may also perform non-identical functions and interact with each other. Here we present results of a laboratory experimental study aimed at elucidating whether interspecific interactions among species within a single nematode trophic group, bacterivores, (1) affect population development and community structure, and (2) depend on food availability. We studied the population growth of Rhabditis (Pellioditis) marina, a rhabditid nematode known to favour very high food densities when in monoculture, and of Diplolaimelloides meyli and D. oschei, congeneric Monhysteridae known to perform better in monocultures at intermediate food availability. Both Diplolaimel...
This paper presents the scenario of the Engineering courses of the Faculty UnB Gama (FGA) in rela... more This paper presents the scenario of the Engineering courses of the Faculty UnB Gama (FGA) in relation to the number of male newcomers versus the number of female ones. It is possible to see, through analysis of the data collected, that the number of male students is much higher than that of female ones, from the creation of the campus in the second semester of 2008 until now. This occurs despite FGAs efforts in promoting the Engineering courses on campus using an experimental laboratory, through the Girls in Computing Program, supported by the National Council of Scientific and Technologic Development (CNPq), in partnership with the high schools of the region. Lectures are also conducted, focused on the female public, and looking do debunk the idea that Engineering is a typically male-oriented course, and trying to awaken the vocational interest of women towards Engineering. Through the surveys focused in the low rate of women in engineering courses, some things come up: (1) the lac...
This Research Full Paper studies the impact of using Calango language in the introductory learnin... more This Research Full Paper studies the impact of using Calango language in the introductory learning of algorithms and computer programming by Brazilian engineering undergraduates. Calango is an educational multi-platform tool designed to facilitate algorithm learning and provide a simple syntax that enables developing advanced logic, so that students concentrate on logic without worrying about language details, considering its based on Portuguese pseudocode commands. A survey was conducted to evaluate if the teaching methods and tools used in the engineering introductory computer programming course were helpful. The questionnaire was applied at the end of four consecutive semesters of lecturing the course, and five questions were selected to analyze Calango’s influence in the learning process. Approximately 95% of the participants agreed that Calango should continue in the class. Students reported that the learning of C language was more accessible due to the initial contact with Cal...
To meet socio-cultural demands imposed by the new millennium and its implications for education, ... more To meet socio-cultural demands imposed by the new millennium and its implications for education, it was necessary for teachers and students to participate actively in the teaching-learning process. In this context, the classes' evaluation by students has been a tool widely used in various universities in different countries. For institutions and teachers, these assessments allow knowing and measuring the results, further analysis of the institutional status, reviewing projects, adjusting goals, diagnosing weaknesses and correcting possible deviations. For the monitoring and improvement of this process, it was necessary to create instruments that aimed to evaluate the performance of the proposed changes. The teaching-learning methodology adopted in the Introduction to Computer Science classes may be a process that makes it difficult to understand the principles of language programming for undergraduate students in Computer Science and related areas, generating high failure and co...
Autonomous vehicles may save 500.000 lives between 2035 and 2045, since humans cause more than 90... more Autonomous vehicles may save 500.000 lives between 2035 and 2045, since humans cause more than 90% of traffic accidents. In order to have an accurate perception of the environment and to avoid accidents, autonomous vehicles require a positioning estimation with only a few centimeters errors. Therefore, state-of-the-art third generation GNSS systems are not suitable for autonomous vehicle applications. In this paper, we propose an improved localization framework for autonomous vehicles via tensor and antenna array based GNSS receiver. As shown in this paper, in challenging urban scenarios, antenna array based GNSS receivers using tensor based algorithms can provide a positioning five times more accurante than state-of-the-art single antenna based GNSS receivers, reducing the positioning error from 149 cm to 30 cm.
Materials Research
The aim of this paper was to determine the influence of machining parameters on the surface layer... more The aim of this paper was to determine the influence of machining parameters on the surface layer, and consequently on the electrochemical properties, of ASTM F138 austenitic stainless steels. Eight different surface conditions were generated in cylindrical samples by turning and polishing. The surface was characterized by surface roughness R a and R t , Vickers microhardness and microstructural characteristics. Cyclic voltammetric tests were performed to evaluate the potential of repassivation and pitting. The surfaces were analyzed by Scanning Electron Microscopy after the electrochemical tests were performed. The cutting parameters were identified to have a significant influence, and the feed rate was as influential as the depth of cut. The use of polishing alone is not sufficient to ensure that a surface has good surface integrity. Even with the polishing application, usually used to produce prostheses, a significant reduction in corrosion resistance occurs if care is not taken to minimize surface machining damage. Corrosion resistance is lower and pitting nucleation is higher in the samples with no polishing and with more severe machining parameters. The tests indicated that softer machining parameters can contribute to an increase in the life of implantable components, reducing the probability of localized corrosion, as well as improving the mechanical properties of prostheses.
Brazilian Journal of Health Review
RESUMO O Hipercortisolismo Subclínico (HS) é uma condição de difícil diagnóstico e está presente ... more RESUMO O Hipercortisolismo Subclínico (HS) é uma condição de difícil diagnóstico e está presente em até 30% dos casos de Incidentaloma Adrenal (IA). O hipercortisolismo em um nível sutil e prolongado tem diversas consequências, tendo como comorbidades associadas mais frequentes a hipertensão arterial sistêmica (HAS), a diabetes mellitus do tipo 2 (DM2), a osteoporose, dislipidemia, a obesidade, doenças cardiovasculares e desequilíbrio no sistema músculo-esquelético. O diagnóstico ainda carece de um padrão ouro e diverge quanto as diversas diretrizes das sociedades de endocrinologia, porém o teste que tem se mostrado mais eficiente é o teste de supressão com 1mg de dexametasona (TSD), que deve ser acompanhado de outros testes de confirmação, que dependem da recomendação da diretriz analisada, os quais podem incluir o cortisol salivar noturno (CSN), o cortisol livre urinário de 24 horas (CLU), os níveis de ACTH e os níveis de sulfato de dehidroepiandrosterona (DHEAS), além de outros testes. O tratamento será decidido entre a intervenção cirúrgica ou pelo tratamento conservador. A decisão quanto o tratamento também não está em consenso na literatura, visto que existe a necessidade de evidências de mais alto nível, entretanto, estudos analisados parecem consentir para um bom prognóstico no que tange a intervenção cirúrgica em detrimento da terapia conservadora, a qual raramente mostra-se benéfica e pode apresentar, inclusive, piora do estado e comorbidades associadas ao HS.
Proceedings of the XXXIII Brazilian Symposium on Software Engineering