Sergio Guedes - Profile on Academia.edu (original) (raw)
Papers by Sergio Guedes
RENOTE, 2010
O desafio de formar o docente online tem levado as instituições de ensino a buscar metodologias q... more O desafio de formar o docente online tem levado as instituições de ensino a buscar metodologias que possibilitem ao futuro professor experimentar e explorar em sua formação diversos aspectos da atividade de docência. Este artigo visa apresentar uma visão geral de uma metodologia para formação de docentes/tutores online, descrevendo suas unidades didáticas. Nossa meta é apresentar os resultados obtidos durante os testes controlados e a sua aplicação em cursos reais de formação docente, e discutindo seus pontos de falha.
CLEI Electronic Journal, 2005
According to 2000 Cense, there are approximately 24.5 million people in Brazil who have some kind... more According to 2000 Cense, there are approximately 24.5 million people in Brazil who have some kind of deficiency, where the visually and mobility impaired are the majority. The government actions are mainly taken toward to basic education, so not many advanced education programs are destined to impaired people. Although some specialized institutions usually offer several technical courses, they are considered basic-level, and don’t prepare them to get more qualified jobs. On the other hand, the number of corporations that offer jobs to them is reduced. Our institution NCE/UFRJ has been developing accessibility tools since 1993, which provides access to information through, but not only, the Internet. Based on this context, NCE/UFRJ has created the Projeto Habilitar, which main goals are to provide intermediate to high-level courses in both administrative and technical areas for impaired people, to develop a teaching methodology and to develop or upgrade accessibility tools to be used...
Case study: practical experience of a technical qualifying project to visually and mobility impaired using accessibility tools
According to 2000 Census, around 24.5 million people in Brazil have some kind of deficiency, wher... more According to 2000 Census, around 24.5 million people in Brazil have some kind of deficiency, where the visually and mobility impaired are the majority. Some education programs have been destined to impaired people, but in general, they are considered basic-level programs, once the government has not taken actions toward to advanced education. Some specialized institutions usually offer several technical courses, but they don’t prepare them to get more qualified jobs. On the other hand, the number of corporations that offer jobs to them is reduced. NCE/UFRJ, our institution, has been developing accessibility tools for the visually impaired since 1993, and for the mobility impaired since 2003. These tools provide access to information, promoting a social integration perspective. Based on this scenario, NCE/UFRJ has created a program named Projeto Habilitar (Habilitar Project). We have two main objectives in this project; to offer from intermediate to high-level courses in both administrative and technical areas for visually and mobility impaired and to develop a teaching methodology, upgrading or developing accessibility tools to be used in future courses and by other institutions as well. The strategy adopted to initiate this project was selecting a course not designed to impaired people and adequate it to them. A course from Cisco Networking Academy Program, implemented by Cisco Systems Inc., the world’s biggest corporation in networking technology, was chosen to be a pilot course.
Anais do X Simpósio em Sistemas Computacionais de Alto Desempenho (WSCAD 2009), 2009
Este artigo apresenta a arquitetura e os resultados da avaliação de desempenho do supercomputador... more Este artigo apresenta a arquitetura e os resultados da avaliação de desempenho do supercomputador Netuno, um cluster de alto desempenho recentemente instalado na UFRJ. São apresentados detalhes tanto de sua arquitetura como dos softwares básicos e de middleware utilizados na sua construção. Os resultados de avaliação obtidos registram um desempenho de 16,2 Tflops sustentados para o benchmark HPL (High Performance Linpack), o que colocou o supercomputador Netuno na 138ª posição na lista Top500 de junho de 2008. Atualmente, o supercomputador Netuno atende diversas instituições de ensino e pesquisa no Brasil, participantes das redes temáticas de pesquisa de Geofísica Aplicada e de Oceanografia (REMO), patrocinadas pala Petrobras.
Inclusão Social De Ex-Presidiários
Conhecimento Em Destaque, May 5, 2013
Work distribution for parallel ZSweep algorithm
16th Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI 2003)
Abstract Distributed systems such as clusters of PCs are low-cost alternatives for running parall... more Abstract Distributed systems such as clusters of PCs are low-cost alternatives for running parallel rendering systems, but they have high communication overhead, and limited memory capacity on each processing node. We focus on the strategy for distributing the ...
International Journal of Parallel Programming, 2012
This paper presents the Netuno supercomputer, a large-scale cluster installed at Federal Universi... more This paper presents the Netuno supercomputer, a large-scale cluster installed at Federal University of Rio de Janeiro in Brazil. A detailed performance evaluation of Netuno is presented, depicting its computational and I/O performance, as well as the results for two real-world applications. Since building a highperformance cluster for running a wide range of applications is a non-trivial task, some lessons learned from assembling and operating this cluster, such as the excellent performance of the OpenMPI library, and the relevance of employing an efficient parallel file system over the traditional NFS system, can be useful knowledge to support the design of new systems. Currently, Netuno is being heavily used to run large scale simulations in the areas of ocean modeling, meteorology, engineering, physics, and geophysics.
The Experience in Designing and Building the High Performance Cluster Netuno
2011 23rd International Symposium on Computer Architecture and High Performance Computing, 2011
Abstract This paper presents a description and the evaluation of the Netuno supercomputer, a high... more Abstract This paper presents a description and the evaluation of the Netuno supercomputer, a high-performance cluster installed at Federal University of Rio de Janeiro in Brazil. The results for the High Performance Linpack (HPL) benchmark and two real applications are ...
Uma proposta de heurísticas para avaliação de interfaces de Ambientes Educacionais a Distância
ABSTRACT
Tolerância a Falhas na Visualização Paralela de Oceanos em Clusters de PCs
ABSTRACT
In this paper we address a very important issue in parallel rendering systems, reliability. Distr... more In this paper we address a very important issue in parallel rendering systems, reliability. Distributed systems, such as clusters of PCs, are low-cost alternatives for running parallel rendering systems. However, distributed systems are usually not reliable, machines can fail during the rendering process, resulting in incomplete final images. Therefore, our goal is to take advantage of specific features of the parallel rendering applications, like tile-based computation, to include mechanisms to dynamically detect machine failure and automatically process tasks retrieval, with low overhead and no extra hardware. We developed three different parallel rendering systems, all based on the Parallel ZSweep algorithm , to provide fault-tolerance in different ways. Our experimental results show that the three systems present a small overhead to detect the failures, and when a failure occurs, the redistribution of the work does not degrade the system performance. We conclude that it is possible to provide fault-tolerance at low-cost in a cluster of PCs.
Program Committee and Reviewers
ieeexplore.ieee.org
Andre Bulcao (Petrobras) Andre Maximo (UFRJ) Cristiana Bentes (UERJ) Cristina Boeres (UFF) Gabrie... more Andre Bulcao (Petrobras) Andre Maximo (UFRJ) Cristiana Bentes (UERJ) Cristina Boeres (UFF) Gabriel Silva (UFRJ) Joao Comba (UFRGS) Lauro Whately (UFRJ) L��cia MA Drummond (UFF) Marcelo Lobosco (UFJF) Rodrigo Weber dos Santos (UFJF) Ricardo Farias (UFRJ) Vinod Rebello (UFF) Wagner Meira (UFMG) ... Alexandre Sena (LaSalle-RJ) Aline Nascimento (UFF) Andr�� Maximo (UFRJ) Cristiana Bentes (UERJ) Cristina Boeres (UFF) Diego Dutra (UFRJ) Gabriel P. Silva (UFRJ) Guilherme Cox (UFRJ) Jo��o Comba (UFRGS) Lauro ...
The Experience in Designing and Building the High Performane Cluster Netuno
2011 23rd International Symposium on Computer Architecture and High Performance Computing, 2011
This paper presents a description and the evaluation of the Netuno supercomputer, a high-performa... more This paper presents a description and the evaluation of the Netuno supercomputer, a high-performance cluster installed at Federal University of Rio de Janeiro in Brazil. The results for the High Performance Linpack (HPL) benchmark and two real applications are ...
Program committee and reviewers
Human Immunology, 1989
Andre Bulcao (Petrobras) Andre Maximo (UFRJ) Cristiana Bentes (UERJ) Cristina Boeres (UFF) Gabrie... more Andre Bulcao (Petrobras) Andre Maximo (UFRJ) Cristiana Bentes (UERJ) Cristina Boeres (UFF) Gabriel Silva (UFRJ) Joao Comba (UFRGS) Lauro Whately (UFRJ) L��cia MA Drummond (UFF) Marcelo Lobosco (UFJF) Rodrigo Weber dos Santos (UFJF) Ricardo Farias (UFRJ) Vinod Rebello (UFF) Wagner Meira (UFMG) ... Alexandre Sena (LaSalle-RJ) Aline Nascimento (UFF) Andr�� Maximo (UFRJ) Cristiana Bentes (UERJ) Cristina Boeres (UFF) Diego Dutra (UFRJ) Gabriel P. Silva (UFRJ) Guilherme Cox (UFRJ) Jo��o Comba (UFRGS) Lauro ...
The Experience in Designing and Building the High Performance Cluster Netuno
2011 23rd International Symposium on Computer Architecture and High Performance Computing, 2011
Abstract This paper presents a description and the evaluation of the Netuno supercomputer, a high... more Abstract This paper presents a description and the evaluation of the Netuno supercomputer, a high-performance cluster installed at Federal University of Rio de Janeiro in Brazil. The results for the High Performance Linpack (HPL) benchmark and two real applications are ...
The Experience in Designing and Evaluating the High Performance Cluster Netuno
International Journal of Parallel Programming, 2012
ABSTRACT This paper presents the Netuno supercomputer, a large-scale cluster installed at Federal... more ABSTRACT This paper presents the Netuno supercomputer, a large-scale cluster installed at Federal University of Rio de Janeiro in Brazil. A detailed performance evaluation of Netuno is presented, depicting its computational and I/O performance, as well as the results for two real-world applications. Since building a high- performance cluster for running a wide range of applications is a non-trivial task, some lessons learned from assembling and operating this cluster, such as the excellent performance of the OpenMPI library, and the relevance of employing an efficient parallel file system over the traditional NFS system, can be useful knowledge to support the design of new systems. Currently, Netuno is being heavily used to run large scale simulations in the areas of ocean modeling, meteorology, engineering, physics, and geophysics.
TEXTO: As diferenças fundamentais entre o sistema de créditos e o regime seriado dizem respeito à... more TEXTO: As diferenças fundamentais entre o sistema de créditos e o regime seriado dizem respeito à forma como os conteúdos são organizados e distribuídos em disciplinas. Enquanto no regime de créditos, a base de organização é a carga horária semanal, ou o número de horas-aula semanais, que define os módulos disciplinares com cargas múltiplas de 15 horas semestrais, já que o semestre é constituído de 15 semanas efetivas de aulas e cada 15 horas equivale a 1 (um) crédito. Assim, os conteúdos das matérias são distribuídos pelos módulos, que são chamados de disciplinas e as disciplinas são organizadas em um fluxograma de compromissos, com seqüências pré-estabelecidas em quase toda a sua extensão, o que caracteriza o sistema de créditos, também, como um sistema de requisitos. No sistema seriado a base de organização é o conteúdo, ou a matéria. É a matéria que definirá a disciplina e, consequentemente, a carga horária necessária para se trabalhar o seu conteúdo. O fluxograma do regime seriado é mais simples, porque as disciplinas são organizadas em blocos seqüenciais anuais. O sistema de créditos e requisitos é mais flexível, permitindo ao aluno organizar seu curso conforme suas necessidades, sua disponibilidade de tempo para estudo e suas potencialidades, ficando amarrado apenas a algumas imposições seqüenciais das disciplinas obrigatórias. Facilita a vida de quem trabalha ou tem outros compromissos, que ocupam seu tempo, ou reduzem sua capacidade para o estudo. Esta flexibilização permite, também, que o aluno se organize para realizar mais de um curso universitário ao mesmo tempo, ou dedicar tempo ao estágio profissional ou à iniciação científica. O regime seriado é mais simples em sua organização, mas apresenta maior inércia na sua realização. O aluno realiza menos provas e não se preocupa em organizar seu fluxograma de disciplinas, que praticamente não tem variantes. Em compensação, a reprovação em uma disciplina, traz perdas enormes, fatalmente, levando ao atraso de um ano no curso. Mas ele estuda mais tranqüilo por saber que as matérias que irá fazer serão oferecidas no ano seguinte. Em compensação, cada prova representará um momento crucial na sua vida. Ela toma maior importância que a prova de um regime
Radiation Measurements, 2001
In this work an assembly for indoor 222 Rn measurement is presented. This assembly is made up of ... more In this work an assembly for indoor 222 Rn measurement is presented. This assembly is made up of two acrylic plates (14 cm×14 cm) separated by a distance of 4 mm. To prevent radon daughters from outside entering the assembly (and produce alpha particle tracks striking the CR-39 detector placed in the central region of one of these plates), the borders of these plates were progressively closed, leaving open only a rectangular aperture of 5 mm×4 mm. The size of this opening was determined experimentally, by exposing in two indoor environments assemblies with di erent apertures as follows: (i) all borders open; (ii) two borders closed; (iii) three borders closed; (iv) four borders closed but one containing a 6 cm×4 mm opening; (v) four borders closed but one containing a 2:5 cm×4 mm opening and (vi) four borders closed but one containing a 0:5 cm×4 mm opening. Track density shows a noticeable decrease between assembly (i) and assembly (iii), remaining constant for smaller openings. Only 222 Rn, a noble gas, should enter the assembly independently of the opening size.
RENOTE, 2010
O desafio de formar o docente online tem levado as instituições de ensino a buscar metodologias q... more O desafio de formar o docente online tem levado as instituições de ensino a buscar metodologias que possibilitem ao futuro professor experimentar e explorar em sua formação diversos aspectos da atividade de docência. Este artigo visa apresentar uma visão geral de uma metodologia para formação de docentes/tutores online, descrevendo suas unidades didáticas. Nossa meta é apresentar os resultados obtidos durante os testes controlados e a sua aplicação em cursos reais de formação docente, e discutindo seus pontos de falha.
CLEI Electronic Journal, 2005
According to 2000 Cense, there are approximately 24.5 million people in Brazil who have some kind... more According to 2000 Cense, there are approximately 24.5 million people in Brazil who have some kind of deficiency, where the visually and mobility impaired are the majority. The government actions are mainly taken toward to basic education, so not many advanced education programs are destined to impaired people. Although some specialized institutions usually offer several technical courses, they are considered basic-level, and don’t prepare them to get more qualified jobs. On the other hand, the number of corporations that offer jobs to them is reduced. Our institution NCE/UFRJ has been developing accessibility tools since 1993, which provides access to information through, but not only, the Internet. Based on this context, NCE/UFRJ has created the Projeto Habilitar, which main goals are to provide intermediate to high-level courses in both administrative and technical areas for impaired people, to develop a teaching methodology and to develop or upgrade accessibility tools to be used...
Case study: practical experience of a technical qualifying project to visually and mobility impaired using accessibility tools
According to 2000 Census, around 24.5 million people in Brazil have some kind of deficiency, wher... more According to 2000 Census, around 24.5 million people in Brazil have some kind of deficiency, where the visually and mobility impaired are the majority. Some education programs have been destined to impaired people, but in general, they are considered basic-level programs, once the government has not taken actions toward to advanced education. Some specialized institutions usually offer several technical courses, but they don’t prepare them to get more qualified jobs. On the other hand, the number of corporations that offer jobs to them is reduced. NCE/UFRJ, our institution, has been developing accessibility tools for the visually impaired since 1993, and for the mobility impaired since 2003. These tools provide access to information, promoting a social integration perspective. Based on this scenario, NCE/UFRJ has created a program named Projeto Habilitar (Habilitar Project). We have two main objectives in this project; to offer from intermediate to high-level courses in both administrative and technical areas for visually and mobility impaired and to develop a teaching methodology, upgrading or developing accessibility tools to be used in future courses and by other institutions as well. The strategy adopted to initiate this project was selecting a course not designed to impaired people and adequate it to them. A course from Cisco Networking Academy Program, implemented by Cisco Systems Inc., the world’s biggest corporation in networking technology, was chosen to be a pilot course.
Anais do X Simpósio em Sistemas Computacionais de Alto Desempenho (WSCAD 2009), 2009
Este artigo apresenta a arquitetura e os resultados da avaliação de desempenho do supercomputador... more Este artigo apresenta a arquitetura e os resultados da avaliação de desempenho do supercomputador Netuno, um cluster de alto desempenho recentemente instalado na UFRJ. São apresentados detalhes tanto de sua arquitetura como dos softwares básicos e de middleware utilizados na sua construção. Os resultados de avaliação obtidos registram um desempenho de 16,2 Tflops sustentados para o benchmark HPL (High Performance Linpack), o que colocou o supercomputador Netuno na 138ª posição na lista Top500 de junho de 2008. Atualmente, o supercomputador Netuno atende diversas instituições de ensino e pesquisa no Brasil, participantes das redes temáticas de pesquisa de Geofísica Aplicada e de Oceanografia (REMO), patrocinadas pala Petrobras.
Inclusão Social De Ex-Presidiários
Conhecimento Em Destaque, May 5, 2013
Work distribution for parallel ZSweep algorithm
16th Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI 2003)
Abstract Distributed systems such as clusters of PCs are low-cost alternatives for running parall... more Abstract Distributed systems such as clusters of PCs are low-cost alternatives for running parallel rendering systems, but they have high communication overhead, and limited memory capacity on each processing node. We focus on the strategy for distributing the ...
International Journal of Parallel Programming, 2012
This paper presents the Netuno supercomputer, a large-scale cluster installed at Federal Universi... more This paper presents the Netuno supercomputer, a large-scale cluster installed at Federal University of Rio de Janeiro in Brazil. A detailed performance evaluation of Netuno is presented, depicting its computational and I/O performance, as well as the results for two real-world applications. Since building a highperformance cluster for running a wide range of applications is a non-trivial task, some lessons learned from assembling and operating this cluster, such as the excellent performance of the OpenMPI library, and the relevance of employing an efficient parallel file system over the traditional NFS system, can be useful knowledge to support the design of new systems. Currently, Netuno is being heavily used to run large scale simulations in the areas of ocean modeling, meteorology, engineering, physics, and geophysics.
The Experience in Designing and Building the High Performance Cluster Netuno
2011 23rd International Symposium on Computer Architecture and High Performance Computing, 2011
Abstract This paper presents a description and the evaluation of the Netuno supercomputer, a high... more Abstract This paper presents a description and the evaluation of the Netuno supercomputer, a high-performance cluster installed at Federal University of Rio de Janeiro in Brazil. The results for the High Performance Linpack (HPL) benchmark and two real applications are ...
Uma proposta de heurísticas para avaliação de interfaces de Ambientes Educacionais a Distância
ABSTRACT
Tolerância a Falhas na Visualização Paralela de Oceanos em Clusters de PCs
ABSTRACT
In this paper we address a very important issue in parallel rendering systems, reliability. Distr... more In this paper we address a very important issue in parallel rendering systems, reliability. Distributed systems, such as clusters of PCs, are low-cost alternatives for running parallel rendering systems. However, distributed systems are usually not reliable, machines can fail during the rendering process, resulting in incomplete final images. Therefore, our goal is to take advantage of specific features of the parallel rendering applications, like tile-based computation, to include mechanisms to dynamically detect machine failure and automatically process tasks retrieval, with low overhead and no extra hardware. We developed three different parallel rendering systems, all based on the Parallel ZSweep algorithm , to provide fault-tolerance in different ways. Our experimental results show that the three systems present a small overhead to detect the failures, and when a failure occurs, the redistribution of the work does not degrade the system performance. We conclude that it is possible to provide fault-tolerance at low-cost in a cluster of PCs.
Program Committee and Reviewers
ieeexplore.ieee.org
Andre Bulcao (Petrobras) Andre Maximo (UFRJ) Cristiana Bentes (UERJ) Cristina Boeres (UFF) Gabrie... more Andre Bulcao (Petrobras) Andre Maximo (UFRJ) Cristiana Bentes (UERJ) Cristina Boeres (UFF) Gabriel Silva (UFRJ) Joao Comba (UFRGS) Lauro Whately (UFRJ) L��cia MA Drummond (UFF) Marcelo Lobosco (UFJF) Rodrigo Weber dos Santos (UFJF) Ricardo Farias (UFRJ) Vinod Rebello (UFF) Wagner Meira (UFMG) ... Alexandre Sena (LaSalle-RJ) Aline Nascimento (UFF) Andr�� Maximo (UFRJ) Cristiana Bentes (UERJ) Cristina Boeres (UFF) Diego Dutra (UFRJ) Gabriel P. Silva (UFRJ) Guilherme Cox (UFRJ) Jo��o Comba (UFRGS) Lauro ...
The Experience in Designing and Building the High Performane Cluster Netuno
2011 23rd International Symposium on Computer Architecture and High Performance Computing, 2011
This paper presents a description and the evaluation of the Netuno supercomputer, a high-performa... more This paper presents a description and the evaluation of the Netuno supercomputer, a high-performance cluster installed at Federal University of Rio de Janeiro in Brazil. The results for the High Performance Linpack (HPL) benchmark and two real applications are ...
Program committee and reviewers
Human Immunology, 1989
Andre Bulcao (Petrobras) Andre Maximo (UFRJ) Cristiana Bentes (UERJ) Cristina Boeres (UFF) Gabrie... more Andre Bulcao (Petrobras) Andre Maximo (UFRJ) Cristiana Bentes (UERJ) Cristina Boeres (UFF) Gabriel Silva (UFRJ) Joao Comba (UFRGS) Lauro Whately (UFRJ) L��cia MA Drummond (UFF) Marcelo Lobosco (UFJF) Rodrigo Weber dos Santos (UFJF) Ricardo Farias (UFRJ) Vinod Rebello (UFF) Wagner Meira (UFMG) ... Alexandre Sena (LaSalle-RJ) Aline Nascimento (UFF) Andr�� Maximo (UFRJ) Cristiana Bentes (UERJ) Cristina Boeres (UFF) Diego Dutra (UFRJ) Gabriel P. Silva (UFRJ) Guilherme Cox (UFRJ) Jo��o Comba (UFRGS) Lauro ...
The Experience in Designing and Building the High Performance Cluster Netuno
2011 23rd International Symposium on Computer Architecture and High Performance Computing, 2011
Abstract This paper presents a description and the evaluation of the Netuno supercomputer, a high... more Abstract This paper presents a description and the evaluation of the Netuno supercomputer, a high-performance cluster installed at Federal University of Rio de Janeiro in Brazil. The results for the High Performance Linpack (HPL) benchmark and two real applications are ...
The Experience in Designing and Evaluating the High Performance Cluster Netuno
International Journal of Parallel Programming, 2012
ABSTRACT This paper presents the Netuno supercomputer, a large-scale cluster installed at Federal... more ABSTRACT This paper presents the Netuno supercomputer, a large-scale cluster installed at Federal University of Rio de Janeiro in Brazil. A detailed performance evaluation of Netuno is presented, depicting its computational and I/O performance, as well as the results for two real-world applications. Since building a high- performance cluster for running a wide range of applications is a non-trivial task, some lessons learned from assembling and operating this cluster, such as the excellent performance of the OpenMPI library, and the relevance of employing an efficient parallel file system over the traditional NFS system, can be useful knowledge to support the design of new systems. Currently, Netuno is being heavily used to run large scale simulations in the areas of ocean modeling, meteorology, engineering, physics, and geophysics.
TEXTO: As diferenças fundamentais entre o sistema de créditos e o regime seriado dizem respeito à... more TEXTO: As diferenças fundamentais entre o sistema de créditos e o regime seriado dizem respeito à forma como os conteúdos são organizados e distribuídos em disciplinas. Enquanto no regime de créditos, a base de organização é a carga horária semanal, ou o número de horas-aula semanais, que define os módulos disciplinares com cargas múltiplas de 15 horas semestrais, já que o semestre é constituído de 15 semanas efetivas de aulas e cada 15 horas equivale a 1 (um) crédito. Assim, os conteúdos das matérias são distribuídos pelos módulos, que são chamados de disciplinas e as disciplinas são organizadas em um fluxograma de compromissos, com seqüências pré-estabelecidas em quase toda a sua extensão, o que caracteriza o sistema de créditos, também, como um sistema de requisitos. No sistema seriado a base de organização é o conteúdo, ou a matéria. É a matéria que definirá a disciplina e, consequentemente, a carga horária necessária para se trabalhar o seu conteúdo. O fluxograma do regime seriado é mais simples, porque as disciplinas são organizadas em blocos seqüenciais anuais. O sistema de créditos e requisitos é mais flexível, permitindo ao aluno organizar seu curso conforme suas necessidades, sua disponibilidade de tempo para estudo e suas potencialidades, ficando amarrado apenas a algumas imposições seqüenciais das disciplinas obrigatórias. Facilita a vida de quem trabalha ou tem outros compromissos, que ocupam seu tempo, ou reduzem sua capacidade para o estudo. Esta flexibilização permite, também, que o aluno se organize para realizar mais de um curso universitário ao mesmo tempo, ou dedicar tempo ao estágio profissional ou à iniciação científica. O regime seriado é mais simples em sua organização, mas apresenta maior inércia na sua realização. O aluno realiza menos provas e não se preocupa em organizar seu fluxograma de disciplinas, que praticamente não tem variantes. Em compensação, a reprovação em uma disciplina, traz perdas enormes, fatalmente, levando ao atraso de um ano no curso. Mas ele estuda mais tranqüilo por saber que as matérias que irá fazer serão oferecidas no ano seguinte. Em compensação, cada prova representará um momento crucial na sua vida. Ela toma maior importância que a prova de um regime
Radiation Measurements, 2001
In this work an assembly for indoor 222 Rn measurement is presented. This assembly is made up of ... more In this work an assembly for indoor 222 Rn measurement is presented. This assembly is made up of two acrylic plates (14 cm×14 cm) separated by a distance of 4 mm. To prevent radon daughters from outside entering the assembly (and produce alpha particle tracks striking the CR-39 detector placed in the central region of one of these plates), the borders of these plates were progressively closed, leaving open only a rectangular aperture of 5 mm×4 mm. The size of this opening was determined experimentally, by exposing in two indoor environments assemblies with di erent apertures as follows: (i) all borders open; (ii) two borders closed; (iii) three borders closed; (iv) four borders closed but one containing a 6 cm×4 mm opening; (v) four borders closed but one containing a 2:5 cm×4 mm opening and (vi) four borders closed but one containing a 0:5 cm×4 mm opening. Track density shows a noticeable decrease between assembly (i) and assembly (iii), remaining constant for smaller openings. Only 222 Rn, a noble gas, should enter the assembly independently of the opening size.