Ensinar matemática em Subúrbia (1989-96): estudo de caso sobre um grupo de professores

Dissertação de mestrado em Ciências da Educação: área de Educação e Desenvolvimento

A visualização espacial e a aprendizagem da matemática: um estudo no 1º ciclo do ensino básico

Dissertação de mestrado em Ciências da Educação: área de Educação e Desenvolvimento

Conexões matemáticas num contexto de actividades de aplicação, investigação e modelação matemática: um estudo no 2º ciclo do ensino básico

Dissertação de mestrado em Ciências da Educação: área de Educação e Desenvolvimento

O computador no ensino da Matemática: uma contribuição para o estudo das concepções e práticas dos professores

Dissertação de mestrado em Ciências da Educação: área de Educação e Desenvolvimento

Identidade profissional dos professores de Matemática: processos de formação

Dissertação de mestrado em Ciências da Educação: área de Educação e Desenvolvimento

A construção da identidade profissional dos professores do ensino secundário: um estudo centrado em professores de Português, Matemática e Economia

Dissertação de mestrado em Ciências da Educação: área de Educação e Desenvolvimento

O acompanhamento local como modelo de desenvolvimento curricular em matemática

Dissertação de mestrado em Ciências da Educação: área de Educação e Desenvolvimento

Dynamic global scheduling of parallel real-time tasks

High-level parallel languages offer a simple way for application programmers to specify parallelism in a form that easily scales with problem size, leaving the scheduling of the tasks onto processors to be performed at runtime. Therefore, if the underlying system cannot efficiently execute those applications on the available cores, the benefits will be lost. In this paper, we consider how to schedule highly heterogenous parallel applications that require real-time performance guarantees on multicore processors. The paper proposes a novel scheduling approach that combines the global Earliest Deadline First (EDF) scheduler with a priority-aware work-stealing load balancing scheme, which enables parallel realtime tasks to be executed on more than one processor at a given time instant. Experimental results demonstrate the better scalability and lower scheduling overhead of the proposed approach comparatively to an existing real-time deadline-oriented scheduling class for the Linux kernel.

Dynamical analysis of the global warming

Global warming is a major concern nowadays. Weather conditions are changing, and it seems that human activity is one of the main causes. In fact, since the beginning of the industrial revolution, the burning of fossil fuels has increased the nonnatural emissions of carbon dioxide to the atmosphere. Carbon dioxide is a greenhouse gas that absorbs the infrared radiation produced by the reflection of the sunlight on the Earth’s surface, trapping the heat in the atmosphere. Global warming and the associated climate changes are being the subject of intensive research due to their major impact on social, economic, and health aspects of human life. This paper studies the global warming trend in the perspective of dynamical systems and fractional calculus, which is a new standpoint in this context. Worldwide distributed meteorological stations and temperature records for the last 100 years are analysed. It is shown that the application of Fourier transforms and power law trend lines leads to an assertive representation of the global warming dynamics and a simpler analysis of its characteristics.

A aprendizagem da matemática no 1º ciclo através de atividades de investigação numa comunidade de aprendizagem

Este artigo baseia-se na investigação que incidiu no trabalho matemático realizado com os meus alunos durante o seu 4º ano de escolaridade no decorrer do ano letivo de 2011/2012. O estudo teve como objetivo compreender como é que os alunos vão desenvolvendo o conhecimento matemático através da articulação de investigações e tarefas exploratórias, feitas individualmente ou em pequenos grupos com a posterior comunicação e discussão dos resultados dessas investigações com toda a turma. A metodologia utilizada assenta no paradigma interpretativo numa abordagem qualitativa. A investigação incidiu nos aspetos decorrentes das ações dos participantes sendo os dados recolhidos diretamente dos momentos de trabalho com os alunos no qual eu assumi o papel de observadora participante. As observações foram registadas em notas de campo e através de registo de audiovisuais. A investigação revelou ser possível os alunos progredirem no currículo de Matemática através do seu envolvimento em investigações matemáticas e suas posteriores discussões na turma. Revelou também que desenvolvem conhecimento matemático através das investigações e que esse conhecimento é aperfeiçoado, retificado e partilhado nas discussões em coletivo (com toda a turma) sobre essas investigações.

Global-EDF scheduling of multimode real- time systems considering mode independent tasks

Embedded real-time systems often have to support the embedding system in very different and changing application scenarios. An aircraft taxiing, taking off and in cruise flight is one example. The different application scenarios are reflected in the software structure with a changing task set and thus different operational modes. At the same time there is a strong push for integrating previously isolated functionalities in single-chip multicore processors. On such multicores the behavior of the system during a mode change, when the systems transitions from one mode to another, is complex but crucial to get right. In the past we have investigated mode change in multiprocessor systems where a mode change requires a complete change of task set. Now, we present the first analysis which considers mode changes in multicore systems, which use global EDF to schedule a set of mode independent (MI) and mode specific (MS) tasks. In such systems, only the set of MS tasks has to be replaced during mode changes, without jeopardizing the schedulability of the MI tasks. Of prime concern is that the mode change is safe and efficient: i.e. the mode change needs to be performed in a predefined time window and no deadlines may be missed as a function of the mode change.

Resource sharing in global fixed-priority preemptive multiprocessor scheduling

In this paper we consider global fixed-priority preemptive multiprocessor scheduling of constrained-deadline sporadic tasks that share resources in a non-nested manner. We develop a novel resource-sharing protocol and a corresponding schedulability test for this system. We also develop the first schedulability analysis of priority inheritance protocol for the aforementioned system. Finally, we show that these protocols are efficient (based on the developed schedulability tests) for a class of priority-assignments called reasonable priority-assignments.

From local to global importance measures of uncertainty propagation in composite structures

The influence of uncertainties of input parameters on output response of composite structures is investigated in this paper. In particular, the effects of deviations in mechanical properties, ply angles, ply thickness and on applied loads are studied. The uncertainty propagation and the importance measure of input parameters are analysed using three different approaches: a first-order local method, a Global Sensitivity Analysis (GSA) supported by a variance-based method and an extension of local variance to estimate the global variance over the domain of inputs. Sample results are shown for a shell composite laminated structure built with different composite systems including multi-materials. The importance measures of input parameters on structural response based on numerical results are established and discussed as a function of the anisotropy of composite materials. Needs for global variance methods are discussed by comparing the results obtained from different proposed methodologies. The objective of this paper is to contribute for the use of GSA techniques together with low expensive local importance measures.

A synchronous transition protocol with periodicity for global scheduling of multimode real-time systems on multiprocessors

We consider the global scheduling problem of multimode real-time systems upon identical multiprocessor platforms. During the execution of a multimode system, the system can change from one mode to another such that the current task set is replaced with a new task set. Thereby, ensuring that deadlines are met requires not only that a schedulability test is performed on tasks in each mode but also that (i) a protocol for transitioning from one mode to another is specified and (ii) a schedulability test for each transition is performed. In this paper, we extend the synchronous transition protocol SM-MSO in order to take into account mode-independent tasks [1], i.e., tasks of which the execution pattern must not be jeopardized by the mode changes.

Two protocols without periodicity for the global and preemptive scheduling problem of multi-mode real-time systems upon multiprocessor Platforms

We consider the problem of scheduling a multi-mode real-time system upon identical multiprocessor platforms. Since it is a multi-mode system, the system can change from one mode to another such that the current task set is replaced with a new task set. Ensuring that deadlines are met requires not only that a schedulability test is performed on tasks in each mode but also that (i) a protocol for transitioning from one mode to another is specified and (ii) a schedulability test for each transition is performed. We propose two protocols which ensure that all the expected requirements are met during every transition between every pair of operating modes of the system. Moreover, we prove the correctness of our proposed algorithms by extending the theory about the makespan determination problem.