A Hybrid Recommender Strategy on an Expanded Content Manager in Formal Learning

The main topic of this paper is to find ways to improve learning in a formal Higher Education Area. In this environment, the teacher publishes or suggests contents that support learners in a given course, as supplement of classroom training. Generally, these materials are pre-stored and not changeable. These contents are typically published in learning management systems (the Moodle platform emerges as one of the main choices) or in sites created and maintained on the web by teachers themselves. These scenarios typically include a specific group of students (class) and a given period of time (semester or school year). Contents reutilization often needs replication and its update requires new edition and new submission by teachers. Normally, these systems do not allow learners to add new materials, or to edit existing ones. The paper presents our motivations, and some related concepts and works. We describe the concepts of sequencing and navigation in adaptive learning systems, followed by a short presentation of some of these systems. We then discuss the effects of social interaction on the learners’ choices. Finally, we refer some more related recommender systems and their applicability in supporting learning. One central idea from our proposal is that we believe that students with the same goals and with similar formal study time can benefit from contents' assessments made by learners that already have completed the same courses and have studied the same contents. We present a model for personalized recommendation of learning activities to learners in a formal learning context that considers two systems. In the extended content management system, learners can add new materials, select materials from teachers and from other learners, evaluate and define the time spent studying them. Based on learner profiles and a hybrid recommendation strategy, combining conditional and collaborative filtering, our second system will predict learning activities scores and offers adaptive and suitable sequencing learning contents to learners. We propose that similarities between learners can be based on their evaluation interests and their recent learning history. The recommender support subsystem aims to assist learners at each step suggesting one suitable ordered list of LOs, by decreasing order of relevance. The proposed model has been implemented in the Moodle Learning Management System (LMS), and we present the system’s architecture and design. We will evaluate it in a real higher education formal course and we intend to present experimental results in the near future

A Parallel and Distributed Framework for Constraint Solving

With the increased availability of affordable parallel and distributed hardware, programming models for these architectures has become the focus of significant attention. Constraint programming, which can be seen as the encoding of processes as a Constraint Satisfaction Problem, because of its data-driven and control-insensitive approach is a prime candidate to serve as the basis for a framework which effectively exploits parallel architectures. To effectually apply the power of distributed computational systems, there must be an effective sharing of the work involved in the search for a solution to a Constraint Satisfaction Problem (CSP) between all the participating agents, and it must happen dynamically, as it is hard to predict the effort associated with the exploration of some part of the search space. We describe and provide an initial experimental assessment of an implementation of a work stealing-based approach to distributed CSP solving, which relies on multiple back-ends for the distributed computing mechanisms -- from the multicore CPU to supercomputer clusters running MPI or other interprocess communication platforms

On the Scalability of Constraint Programming on Hierarchical Multiprocessor Systems

Recent developments in computer architecture progress towards systems with large core count, which expose more parallelism to applications, creating a hierarchical setup at the node and cluster levels. To take advantage of all this parallelism, applications must carefully exploit the different levels of the system which, if ignored, may yield surprising results. This aggravates the already difficult task of parallel programming. Declarative approaches such as those based on constraints are attractive to parallel programming because they concentrate on the logic of the problem. They have been successfully applied to hard problems, which usually involve searching through large problem spaces, a computationally intensive task but with potential for parallelization. Tree search algorithms play an important role in research areas such as constraint satisfaction or optimisation, and artificial intelligence. Tree search lends itself naturally to parallelization by exploiting different branches of the tree but scalability may be harder to achieve due to the high dynamic load balancing requirements. In this paper we present a high-level declarative approach based on constraints and show how it benefits from an efficient dynamic load balancing based on work stealing targeted at large-scale. We focus on the implementation of a hierarchical work stealing scheme using a different programming model, GPI. Experimentation brought encouraging results on up to 512 cores on large instances of satisfaction and optimisation problems

Recommendations to transfer and adapt good practices in health promotion and prevention of chronic diseases: the joint action CHRODIS experience

Retificações nas referências em 17/8/2017As doenças crónicas representam 86% de todas as mortes na Europa e por esse motivo, minimizar este peso torna-se uma prioridade central para a União Europeia e para os seus Estados-membros. Neste contexto, existe uma grande necessidade de identificar, partilhar e transferir exemplos de Boas Práticas (BP) em matéria de promoção da saúde e prevenção de doenças crónicas. A partir deste prossuposto formou-se o consórcio europeu JA-CHRODIS (Joint Action on Chronic Diseases and Promoting Healthy Ageing Across the Life Cycle) cujo principal objetivo é a prevenção de doenças crónicas e a promoção do envelhecimento saudável a partir da facilitação de intercâmbio de BP entre os vários parceiros. Após um processo consultivo e participativo foram identificadas, selecionadas e avaliadas algumas BP europeias que se verificam eficazes na sua área de atuação. Realizaram-se visitas de estudo aos locais de origem das práticas selecionadas por forma a avaliar o seu contexto de implementação e estudar a sua potencialidade de transferibilidade. O resultado final foi a identificação de um conjunto de critérios-chave que constituem um conjunto de recomendações práticas que pretende servir como uma ferramenta facilitadora na transferência de BP.Chronic diseases account for 86% of all deaths in Europe. For this reason, minimizing this burden is a central priority for the European Union and its Member States.Therefore, there is a great need to identify, share and transfer examples of good practice in health promotion and prevention of chronic diseases. In this context, the European consortium JA-CHRODIS (Joint Action on Chronic Diseases and Promoting Healthy Aging Across the Life Cycle) was formed. Its main objective is the prevention of chronic diseases and the promotion of healthy aging through the facilitation of exchange of Good Practices (GP) among the various partners. After a consultative and participative process, some European GP’s which were found to be effective in areas of its performance have been identified, selected and evaluated. Subsequently, partners held study visits on selected GP’s examples in order to assess their implementation context and their transferability potential. The main result was the identification of a set of key criteria that constitute a set of practical recommendations that intend to ser ve as a facilitating tool in GP transfer.info:eu-repo/semantics/publishedVersio

Estratégia Hibrida de Recomendações sobre um Gestor de Conteúdos Ampliado em Ensino Formal

Este artigo tem por objetivo apresentar um Modelo para Recomendação Personalizada de conteúdos de aprendizagem, baseado numa estratégia de recomendação híbrida e no perfil de cada aluno. Incluímos uma proposta para a similaridade entre alunos que reflete os seus interesses em termos das avaliações pretendidas e da proximidade das sequências de atividades de aprendizagem dos diversos alunos. Este modelo prevê, igualmente, a inclusão de novos conteúdos por parte dos alunos e a definição de relacionamentos com os conteúdos existentes. São abordadas as motivações que nos levaram à presente proposta, alguns conceitos e trabalhos relacionados, assim como a arquitetura e desenho da solução, entretanto alvo de protótipo. Por fim são tecidas algumas conclusões

Unbalanced tree search on a manycore system using the GPI programming model

The recent developments in computer architectures progress towards systems with large core count (Manycore) which expose more parallelism to applications. Some applications named irregular and unbalanced applications demand a dynamic and asynchronous load balance implementation to utilize the full performance a Manycore system. For example, the recently established Graph500 benchmark aims at such applications. The UTS benchmark characterizes the performance of such irregular and unbalanced computations with a tree-structured search space that requires continuous dynamic load balancing. GPI is a PGAS API that delivers the full performance of RDMA-enabled networks directly to the application. Its programming model focuses the use of one-sided asynchronous communication, overlapping computation and communication. In this paper we address the dynamic load balancing requirements of unbalanced applications using the GPI programming model. Using the UTS benchmark, we detail the implementation of a work stealing algorithm using GPI and present the performance results. Our performance evaluation shows significant improvements when compared with the optimized MPI version with a maximum performance of 9.5 billion nodes per second on 3072 cores

Characterization and modeling of top spam botnets

The increasing impact of the Internet in the global economy has transformed Botnets into one of the most relevant security threats for citizens, organizations and governments. Despite the significant efforts that have been made over the last years to understand this phenomenon and develop detection techniques and countermeasures, this continues to be a field with big challenges to address. Several approaches can be taken to study Botnets: analyze its source code, which can be a hard task because it is usually unavailable; study the control mechanism, particularly the activity of its Command and Control server(s); study its behavior, by measuring real traffic and collecting relevant statistics. In this work, we have installed some of the most popular spam Botnets, captured the originated traffic and characterized it in order to identify the main trends/patterns of their activity. From the intensive statistics that were collected, it was possible to conclude that there are distinct features between Botnets that can be explored to build efficient detection methodologies. Based on this study, the second part of the paper proposes a generic and systematic model to describe the network dynamics whenever a Botnet threat is detected, defining all actors, dimensions, states and actions that need to be taken into account at each moment. We believe that this type of modeling approach is the basis for developing systematic and integrated frameworks and strategies to predict and fight Botnet threats in an efficient way.This research was supported by Fundação para a Ciência e a Tecnologia, under research project PTDC/EEA-TEL/101880/2008

O efeito dos fatores comportamentais na tensão arterial da população portuguesa sob anti-hipertensores: resultados do 1.º Inquérito Nacional de Saúde com Exame Físico

Dissertação de Mestrado em Saúde Pública, apresentada à Escola Nacional de Saúde Pública da Universidade Nova de Lisboa, 2019Orientação científica de Professor Doutor Baltazar Nunes e Mestre Ana Paula RodriguesIntrodução: A hipertensão arterial é um dos principais fatores de risco para incapacidade e morte por doenças cardiovasculares. Orientações atuais preconizam medidas não farmacológicas de controlo dos valores tensionais centradas em mudanças do estilo de vida. Este estudo teve como objetivo principal estimar a associação entre fatores comportamentais de estilo de vida e a tensão arterial (TA) na população portuguesa sob anti-hipertensores. Material e Métodos: Realizou-se um estudo transversal, com análise dos dados colhidos no 1º Inquérito Nacional de Saúde com Exame Físico 2015. Foram estudados os indivíduos que referiram encontrar-se sob medicação anti-hipertensora nas duas semanas prévias à entrevista. As variáveis comportamentais (consumo adicional de sal, consumo de álcool, consumo de frutos e vegetais, prática de atividade física, hábito tabágico) foram medidas por questionário e os valores de TA sistólica (TAS) e diastólica (TAD) foram obtidos por exame físico. Foram estimadas associações entre as variáveis comportamentais e os valores médios de TA, estratificadas por sexo e ajustadas para variáveis sociodemográficas e obesidade através de um modelo de regressão linear múltipla. Resultados: O consumo de álcool (ß=6,310, IC95% 1,875;10,744) e o hábito tabágico (ß=4,724, IC95% 0,848;8,599) apresentaram-se positivamente associados à média da TAS, em homens, aumentando em média, respetivamente, em 6,3 mmHg e 4,7 mmHg os valores de TAS. O consumo adicional de sal, o consumo de frutos e vegetais e a prática de atividade física não apresentaram associação estatisticamente significativa com os valores de TA, em homens. Nas mulheres, nenhuma associação foi estatisticamente significativa para qualquer variável comportamental. Discussão: Os resultados demonstram, assim, que alterações dos estilos de vida da população portuguesa masculina sob anti-hipertensores, nomeadamente redução dos hábitos tabágicos e hábitos alcoólicos, apresentam um potencial importante em termos de controlo de valores de TAS e, consequentemente, de prevenção de eventos cardiocerebrovasculares.Introduction: Hypertension is one of the main risk factors for disability and death from cardiovascular diseases. Current guidelines include initiatives to control blood pressure values in hypertensive patients that focus on lifestyle changes. The main objective of this study was to estimate the association between behavioural lifestyle factors and blood pressure (BP) in patients under antihypertensive medication. Materials and Methods: An analysis of the data collected in the first National Health Examination Survey 2015 was performed. Individuals who met National Health Examination Survey inclusion criteria and who referred to be under antihypertensive medication in the two weeks prior to the interview were studied. Behavioural lifestyle variables (additional salt intake, alcohol consumption, fruit and vegetables intake, practice of physical activity and smoking habits) were measured by questionnaire, and the systolic (SBP) and diastolic blood pressure (DBP) values were obtained by physical examination. Associations between behavioural variables and mean BP values, stratified by sex and adjusted to sociodemographic variables and obesity, were estimated through a multiple linear regression model. Results: Alcohol consumption (ß=6.310, IC95% 1.875;10.744) and smoking habit (ß=4.724, IC95% 0,848;8,599) were positively associated with mean SBP values in men, increasing the mean SBP values in 6.3 mmHg and 4.7 mmHg, respectively. Additional salt intake, fruit and vegetable consumption, and practice of physical activity were not statistically associated with BP values in men. In women, no association was statistically significant for any behavioural variable. Discussion: The results show that changes in the lifestyles of the male Portuguese population under antihypertensives, in particular reduction of smoking habits and alcoholic habits, represent an important potential in terms of control of SBP values and, consequently, the prevention of cardiocerebrovascular events.N/