Data-centric concurrency control on the java programming language

Dissertação para obtenção do Grau de Mestre em Engenharia Informática

A 1.2 V low noise amplifier with double feedback for high gain and low noise figure

Dissertação para obtenção do Grau de Mestre em Engenharia Eletrotécnica e de Computadores

Maintaining the correctness of transactional memory programs

Dissertação para obtenção do Grau de Doutor em Engenharia Informática

Referenda outcomes and the influence of polls: A social network feedback process

This paper proposes a model to explain the differences between outcomes of referenda and the voting trends suggested by polls. Two main effects are at stake. First, the evolution of the voters' attitudes is conditional on the public information made available to them. Second, the predisposition toward abstention among individuals within each voting group may be different. Our model describes how these two aspects of decision making may interact, showing how publicly available information may amplify the distinct tendency toward abstention between both groups and thus affect the outcome of the referendum.

Preventing atomicity violations with contracts

Concurrent programming is a difficult and error-prone task because the programmer must reason about multiple threads of execution and their possible interleavings. A concurrent program must synchronize the concurrent accesses to shared memory regions, but this is not enough to prevent all anomalies that can arise in a concurrent setting. The programmer can misidentify the scope of the regions of code that need to be atomic, resulting in atomicity violations and failing to ensure the correct behavior of the program. Executing a sequence of atomic operations may lead to incorrect results when these operations are co-related. In this case, the programmer may be required to enforce the sequential execution of those operations as a whole to avoid atomicity violations. This situation is specially common when the developer makes use of services from third-party packages or modules. This thesis proposes a methodology, based on the design by contract methodology, to specify which sequences of operations must be executed atomically. We developed an analysis that statically verifies that a client of a module is respecting its contract, allowing the programmer to identify the source of possible atomicity violations.

Video interaction using pen-based technology

Dissertação para obtenção do Grau de Doutor em Informática

Child programming: an adequate domain specific language for programming specific robots

Dissertação para obtenção do Grau de Mestre em Engenharia Informática

O feedback/la retroalimentación na avaliação da oralidade nas aulas de língua estrangeira

Relatório de Estágio apresentado para cumprimento dos requisitos necessários à obtenção do grau de Mestre em Ensino do Inglês e de Línguas Estrangeiras no 3º ciclo do Ensino Básico e no Secundário

A DSL for querying building data streams of energy, eeather and occupation data

The superfluous consumption of energy is faced by the modern society as a Socio-Economical and Environmental problem of the present days. This situation is worsening given that it is becoming clear that the tendency is to increase energy price every year. It is also noticeable that people, not necessarily proficient in technology, are not able to know where savings can be achieved, due to the absence of accessible awareness mechanisms. One of the home user concerns is to balance the need of reducing energy consumption, while producing the same activity with all the comfort and work efficiency. The common techniques to reduce the consumption are to use a less wasteful equipment, altering the equipment program to a more economical one or disconnecting appliances that are not necessary at the moment. However, there is no direct feedback from this performed actions, which leads to the situation where the user is not aware of the influence that these techniques have in the electrical bill. With the intension to give some control over the home consumption, Energy Management Systems (EMS) were developed. These systems allow the access to the consumption information and help understanding the energy waste. However, some studies have proven that these systems have a clear mismatch between the information that is presented and the one the user finds useful for his daily life, leading to demotivation of use. In order to create a solution more oriented towards the user’s demands, a specially tailored language (DSL) was implemented. This solution allows the user to acquire the information he considers useful, through the construction of questions about his energy consumption. The development of this language, following the Model Driven Development (MDD) approach, took into consideration the ideas of facility managers and home users in the phases of design and validation. These opinions were gathered through meetings with experts and a survey, which was conducted to the purpose of collecting statistics about what home users want to know.

Towards an algorithmic skeleton framework for programming the Intel R Xeon PhiTM processor

The Intel R Xeon PhiTM is the first processor based on Intel’s MIC (Many Integrated Cores) architecture. It is a co-processor specially tailored for data-parallel computations, whose basic architectural design is similar to the ones of GPUs (Graphics Processing Units), leveraging the use of many integrated low computational cores to perform parallel computations. The main novelty of the MIC architecture, relatively to GPUs, is its compatibility with the Intel x86 architecture. This enables the use of many of the tools commonly available for the parallel programming of x86-based architectures, which may lead to a smaller learning curve. However, programming the Xeon Phi still entails aspects intrinsic to accelerator-based computing, in general, and to the MIC architecture, in particular. In this thesis we advocate the use of algorithmic skeletons for programming the Xeon Phi. Algorithmic skeletons abstract the complexity inherent to parallel programming, hiding details such as resource management, parallel decomposition, inter-execution flow communication, thus removing these concerns from the programmer’s mind. In this context, the goal of the thesis is to lay the foundations for the development of a simple but powerful and efficient skeleton framework for the programming of the Xeon Phi processor. For this purpose we build upon Marrow, an existing framework for the orchestration of OpenCLTM computations in multi-GPU and CPU environments. We extend Marrow to execute both OpenCL and C++ parallel computations on the Xeon Phi. We evaluate the newly developed framework, several well-known benchmarks, like Saxpy and N-Body, will be used to compare, not only its performance to the existing framework when executing on the co-processor, but also to assess the performance on the Xeon Phi versus a multi-GPU environment.

Improving Learners’ Motivation through Feedback in English Language Teaching and Learning at Polytechnic School in Benguela, Angola

Currently, it is widely perceived among the English as a Foreign Language (EFL) teaching professionals, that motivation is a central factor for success in language learning. This work aims to examine and raise teachers’ awareness about the role of assessment and feedback in the process of language teaching and learning at polytechnic school in Benguela to develop and/or enhance their students’ motivation for learning. Hence the paper defines and discusses the key terms and, the techniques and strategies for an effective feedback provision in the context under study. It also collects data through the use of interview and questionnaire methods, and suggests the assessment and feedback types to be implemented at polytechnic school in Benguela

Using social semantic knowledge to improve annotations in personal photo collections

Instituto Politécnico de Lisboa (IPL) e Instituto Superior de Engenharia de Lisboa (ISEL)apoio concedido pela bolsa SPRH/PROTEC/67580/2010, que apoiou parcialmente este trabalho

Aprender com as Tecnologias Digitais: um Modelo em eLearning em Contexto de Sala de Aula no Ensino Superior

O estudo de caso tem por objetivo principal analisar e avaliar a utilização de um Ambiente de Aprendizagem Enriquecido pela Tecnologia (TELE) no Ensino Superior, através do que é normalmente designado de eLearning e, perceber, o impacto que estas metodologias estão a ter no ensino presencial, a forma como estão a ser usadas e de que forma alunos e professores têm sido confrontados com esta realidade. Especificamente visa analisar o impacto da implementação de um modelo de eLearning na aprendizagem e perceber a relação entre uma estratégia metodológica suportada pela LMS Moodle na sala de aula, as competências digitais e skills que os alunos têm e de que forma isso resulta em termos de ensino-aprendizagem. O Moodle foi a plataforma de aprendizagem selecionada enquanto suporte ao processo de ensino-aprendizagem na unidade curricular de Edição Multimédia do curso de Licenciatura em Comunicação Social e Cultural da Universidade Católica Portuguesa (UCP), com uma turma de 42 alunos no total. Por conseguinte, foi o ambiente usado para a interação entre os alunos e entre estes com o professor em espaço e tempo extra aula. Com o objetivo de cumprir os objetivos propostos recorreu-se a três instrumentos de recolha de dados: dois questionários aos alunos, em momentos distintos. Primeiro, procurou-se obter conhecimentos sobre as suas competências digitais e, num segundo momento, aferir sobre a perceção e o nível de satisfação dos alunos face ao modelo de aprendizagem implementado; observação não participante de sala de aula (estruturada e naturalista), delimitando-se as seguintes dimensões: estratégias operacionalizadas pelo professor, materiais/recursos e ferramentas utilizadas e práticas e atitudes do aluno; registos da plataforma pela análise das interações entre os alunos e destes com o professor através dos fóruns de discussão. O estudo permitiu atestar o impacto bastante positivo nos níveis de satisfação dos alunos e estabelecer uma relação eficaz entre a tecnologia e a aquisição de aprendizagens significativas: potenciou uma aprendizagem ativa, interativa e um contexto para o trabalho colaborativo; consequente capacidade autorregulatória da aprendizagem; promoveu o desenvolvimento da Literacia digital; possibilitou a adoção de metodologias de aprendizagem diversificadas; contribuiu para o aumento da participação, motivação e entusiasmo dos alunos.

Machine ethics via logic programming

Machine ethics is an interdisciplinary field of inquiry that emerges from the need of imbuing autonomous agents with the capacity of moral decision-making. While some approaches provide implementations in Logic Programming (LP) systems, they have not exploited LP-based reasoning features that appear essential for moral reasoning. This PhD thesis aims at investigating further the appropriateness of LP, notably a combination of LP-based reasoning features, including techniques available in LP systems, to machine ethics. Moral facets, as studied in moral philosophy and psychology, that are amenable to computational modeling are identified, and mapped to appropriate LP concepts for representing and reasoning about them. The main contributions of the thesis are twofold. First, novel approaches are proposed for employing tabling in contextual abduction and updating – individually and combined – plus a LP approach of counterfactual reasoning; the latter being implemented on top of the aforementioned combined abduction and updating technique with tabling. They are all important to model various issues of the aforementioned moral facets. Second, a variety of LP-based reasoning features are applied to model the identified moral facets, through moral examples taken off-the-shelf from the morality literature. These applications include: (1) Modeling moral permissibility according to the Doctrines of Double Effect (DDE) and Triple Effect (DTE), demonstrating deontological and utilitarian judgments via integrity constraints (in abduction) and preferences over abductive scenarios; (2) Modeling moral reasoning under uncertainty of actions, via abduction and probabilistic LP; (3) Modeling moral updating (that allows other – possibly overriding – moral rules to be adopted by an agent, on top of those it currently follows) via the integration of tabling in contextual abduction and updating; and (4) Modeling moral permissibility and its justification via counterfactuals, where counterfactuals are used for formulating DDE.

Decision-making process of Nova Executivos’ students

Field lab: Consumer insights