An integrated formal methods tool-chain and its application to verifying a file system model

Tool interoperability as a mean to achieve integration is among the main goals of the international Grand Challenge initiative. In the context of the Verifiable file system mini-challenge put forward by Rajeev Joshi and Gerard Holzmann, this paper focuses on the integration of different formal methods and tools in modelling and verifying an abstract file system inspired by the Intel (R) Flash File System Core. We combine high-level manual specification and proofs with current state of the art mechanical verification tools into a tool-chain which involves Alloy, VDM++ and HOL. The use of (pointfree) relation modelling provides the glue which binds these tools together.Mondrian Project funded by the Portuguese NSF under contract PTDC/EIA-CCO/108302/200

Alloy meets the algebra of programming: a case study

Relational algebra offers to software engineering the same degree of conciseness and calculational power as linear algebra in other engineering disciplines. Binary relations play the role of matrices with similar emphasis on multiplication and transposition. This matches with Alloy’s lemma “everything is a relation” and with the relational basis of the Algebra of Programming (AoP). Altogether, it provides a simple and coherent approach to checking and calculating programs from abstract models. In this paper, we put Alloy and the Algebra of Programming together in a case study originating from the Verifiable File System mini-challenge put forward by Joshi and Holzmann: verifying the refinement of an abstract file store model into a journaled (FLASH) data model catering to wear leveling and recovery from power loss. Our approach relies on diagrams to graphically express typed assertions. It interweaves model checking (in Alloy) with calculational proofs in a way which offers the best of both worlds. This provides ample evidence of the positive impact in software verification of Alloy’s focus on relations, complemented by induction-free proofs about data structures such as stores and lists.Fundação para a Ciência e a Tecnologia (FCT

Growing Evolution of the Electrification Rate on Heavy Vehicles

In response to environmental impacts and all the limitations caused by fossil fuels, we have been witnessing in recent decades to the sharp development of hybrid electric and electric vehicles, particularly in heavy-duty passenger vehicles. Its proliferation is now widespread in virtually every major vehicle brand, reflecting operator confidence. In order to further mitigate the use of fossil fuels, the trend is to increase supply in 100% electric versions. However, the evolution of recent years, both in manufacturers commercial strategy of major brands and bodybuilders and in sales volume, seems to indicate a new demand stage for this kind of vehicles, which are still making the first steps in Portugal. However, high acquisition costs and limited autonomy are still major obstacles to a faster proliferation of electrification in heavy vehicles. Its strengths such as lower air and noise pollution, in addition to lower operating and maintenance costs, led to a growing acquisition in the Portuguese vehicle market, where 16 new heavy-duty passenger BEV have been sold this year. Real-world operational impacts of these vehicles indicate a energy use between 0.91 and 1.65 kWh/km depending on driving context. It has been also observed that operators are still adapting and not always using the full battery capacity. Keywords: Electrified heavy vehicles, Energy assessment, Driving mode, Load support, State of charg

Avaliação de Riscos para a Segurança da Informação no ISEP Aplicação ao Processo de Notas

Desde que existe informação, há necessidade de criar um sistema que permita gerir e garantir que a informação está segura e que cumpre os requisitos básicos de segurança. Como tal, é necessário desenvolver técnicas e mecanismos para que os requisitos sejam testados e melhorados continuamente. Com esta necessidade em vista, apareceram padrões que dão resposta a um conjunto vasto de problemas, em diferentes sistemas e aplicações diversas. Estes tornaram-se guias de reflexão para quem os analisava, de arquitetura para quem os implementava e modelos para quem os geria. O padrão ISO 27001 dá resposta aos cuidados a ter para se conseguir um sistema de gestão da segurança da informação eficaz e eficiente. Esta norma preocupa-se com os detalhes de aplicação até à forma como é implementado e arquitetado o sistema. Os processos, atividades, fluxos de trabalho são essenciais para que esta norma seja cumprida. É necessário um bom escrutínio dos processos e suas atividades, assim como um fluxo de trabalho bem definido com papéis e responsabilidades de cada ator. É necessário também assegurar a forma como é gerido, a sua verificação e melhoria contínua. Foi aplicado no ISEP um exercício com o qual se pretendeu verificar se os processos e outros aspetos seguiam estes cuidados e se estavam de acordo com a norma. Durante o exercício foram verificados processos dentro de um certo âmbito, todas as suas atividades, papéis e responsabilidades, verificação de recursos, aplicação de controlos e aplicação de uma análise de risco. Esta análise tem como objetivo verificar o nível de segurança dos recursos, algo que a norma ISO 27001 propõe mas não especifica em que moldes. No final deste exercício pretendeu-se melhorar o sistema de gestão de informação do ISEP em vertentes tais como a documentação, a qual especifica quais os passos realizados no decorrer do mesmo.Since there is information, a need exists to create a system that allows managing and ensuring the information is safe and meets the basic security requirements. As such, there was a need to develop techniques and mechanisms for requirements to be tested and continuously improved. With this need in mind, patterns appeared that gave answer to a wide range of problems, different systems and applications. These became guides to those who analyzed the problem, the architecture and who was implementing the models. The ISO 27001 standard addresses the precautions to ensure that a security management system deals with effective and efficient information. This standard is concerned with every detail of how it is implemented and how a system is architected. Processes, activities, workflows become essential for the application of this standard. A good scrutiny of processes and activities, as well as a workflow with well-defined roles and responsibilities for each actor, are required. It is also necessary to ensure the way it is managed, as well as its verification and continuous improvement. In ISEP a process aiming to verify if these and other procedures were followed was run, and if security was in accordance with the standard. During this process it was observed the framework, activities, roles and responsibilities, actions, implementation controls, and a risk analysis was undertaken. Risk analysis intends to verify the security level of resources, as ISO 27001 describes, but without specifying the way to do it. This exercise intended to improve the management system of ISEP, producing documentation describing what steps were performed during the exercise and results obtained

Testes substantivos e o julgamento do auditor

O presente relatório de estágio vem no seguimento da realização do estágio curricular na empresa CFA – Cravo, Fortes e Antão & Associados SROC, Lda., por um período de seis meses. Sendo assim, este relatório tem como objetivo demonstrar o trabalho realizado do longo deste estágio, abarcando grande parte do processo de auditoria e, de forma mais aprofundada, quanto aos testes substantivos e diversos outros testes que requerem o julgamento do auditor. Para tal, foram analisados artigos científicos relevantes para o tema em questão assim como livros e normas. Neste sentido, inicialmente o tema é abordado através de uma vertente teórica de caracter conceptual e normativa acerca do tema do relatório. Posteriormente são abordadas e descritas todas as atividades realizadas durante o estágio curricular. Através da realização deste relatório, foi possível compreender os testes de auditoria realizados e abordados em termos práticos no estágio curricular, estabelecendo ligações entre a vertente teórica e prática, assim como perceber a extensão dos procedimentos de auditoria e testes que o auditor julga serem necessário recorrer nas suas auditorias. Concluiu-se assim que o julgamento aplicado pelo auditor é de extrema importância no momento em que este estima a quantidade e profundidade dos testes a aplicar em uma auditoria. Além disso, os testes substantivos podem ser divididos em testes de detalhe, os quais procuram dar resposta a uma análise mais direta por parte do auditor às rubricas mais relevantes das Demonstrações Financeiras, assim como quanto aos procedimentos analíticos, os quais são efetuados com o intuito de comparar a informação financeira entre períodos.This report follows the completion of the internship at the company CFA – Cravo, Fortes e Antão & Associados SROC, Lda. for a period of six months. Therefore, this report aims to demonstrate the work done during this internship, covering a large part of the audit process and, in a deeper way, regarding the substantive tests and several other audit tests that require the auditor´s judgement. To this end, relevant scientific papers were analysed, as well as books and standards. Therefore, the topic was initially approached in a theoretical and conceptual standard as well as a normative approach to the theme of the report. Subsequently, all the activities carried out during the curricular internship are covered and described. Through the completion of this report, it was possible to understand in a better way the audit tests carried out and approached in a practical way in the curricular internship, creating links between the theoretical and practical stand, as well as understanding the extension of its procedures and tests that the auditor considers fundamental in his work.Mestrado em Contabilidad

The rationale/design of the Guimarães/Vizela study : a multimodal population-based cohort study to determine global cardiovascular risk and disease

Background: Cardiovascular disease and dementia are growing medical and social problems in aging societies. Appropriate knowledge of cardiovascular disease and cognitive decline risk factors (RFs) are critical for global CVR health preventive intervention. Many epidemiological studies use case definition based on data collected/measured in a single visit, a fact that can overestimate prevalence rates and distant from clinical practice demanding criteria. Portugal displays an elevated stroke mortality rate. However, population's global CV risk characterization is limited, namely, considering traditional/nontraditional RF and new intermediate phenotypes of CV and renal disease. Association of hemodynamic variables (pulse wave velocity and central blood pressure) with global CVR stratification, cognitive performance, and kidney disease are practically inexistent at a dwelling population level. Study Design and Methods: After reviewing published data, we designed a population-based cohort study to analyze the prevalence of these cardiovascular RFs and intermediate phenotypes, using random sampling of adult dwellers living in 2 adjacent cities. Strict definition of phenotypes was planned: subjects were observed twice, and several hemodynamic and other biological variables measured at least 3 months apart. Results: Three thousand thirty-eight subjects were enrolled, and extensive data collection (including central and peripheral blood pressure, pulse wave velocity), sample processing, and biobank edification were carried out. One thousand forty-seven cognitive evaluations were performed. Conclusions: Seeking for CV risk reclassification, early identification of subjects at risk, and evidence of early vascular aging and cognitive and renal function decline, using the strict daily clinical practice criteria, will lead to better resource allocation in preventive measures at a population level.(undefined

Measuring user influence in financial microblogs: experiments using stocktwits data

In this paper, we study the effect of graph structure user in- fluence measures in financial social media. In particular, we explore rich and recent data, composed of 1.2 million Stock- Twits messages, from June 2010 to March 2013. These data allow the creation of social network graphs by considering direct active interactions (retweets, shares or replies). Using such graphs and a realistic rolling windows evaluation, we analyzed four user influence measures (indegree, between- ness, page rank and posts) under two criteria: Percentage of Quality Users (PQU), as manually labeled by StockTwits; and the daily sentiment correlation between top lists of in- fluential users and other users. The sentiment was based on a StockTwits labeled dataset and assessed in terms of three selections: overall sentiment (ALL) and filtered by two ma- jor technological companies (Apple – AAPL and Google – GOOG). Promising results were obtained, with several top lists pre- senting PQU values higher than 80% and correlations higher than 0.6. Overall, the best results were achieved by the page rank and posts measures.This work has been supported by COMPETE: POCI-01- 0145-FEDER-007043 and FCT { Funda c~ao para a Ci^encia e Tecnologia within the Project Scope: UID/CEC/00319/2013. We also thank StockTwits for the provision of their data

Técnicas de ligação pavimentos/paredes em reabilitação de edifícios antigos

Tese de mestrado integrado. Engenharia Civil (Especialização em Construções Civis). Faculdade de Engenharia. Universidade do Porto. 200

Desenvolver o cálculo mental no contexto da resolução de problemas de adição e subtração : um estudo com alunos do 2.º ano de escolaridade

Tese de mestrado, Educação (Didática da Matemática), Universidade de Lisboa, Instituto de Educação, 2013Este estudo tem como principal objetivo compreender que estratégias de cálculo mental são usadas por alunos do 2.º ano de escolaridade na resolução de problemas de adição e subtração com números naturais. Especificamente caracteriza as estratégias utilizadas pelos alunos quando resolvem tarefas de adição e subtração, a sua evolução, as dificuldades evidenciadas e a influência do contexto na seleção das estratégias. O quadro teórico está organizado em três áreas: (i) sentido de número; (ii) cálculo mental; (iii) resolução de problemas; e (iv) ambiente de aprendizagem. O estudo segue o paradigma interpretativo e uma abordagem qualitativa, tendo como design o estudo de caso, assente no desenvolvimento de uma experiência de ensino. Os participantes são os cinco alunos do 2.º ano de escolaridade da turma que lecionei no ano letivo 2010/2011. A recolha de dados inclui os registos dos alunos na resolução de problemas, juntamente com gravações vídeo, áudio e notas de campo. A experiência de ensino teve a duração de oito semanas e envolveu a resolução semanal de um problema e duas cadeias de cálculo. As conclusões do estudo revelam que: (i) os alunos utilizam uma grande diversidade de estratégias, e que estas estão relacionadas com os significados dos problemas; (ii) há alunos que usam estratégias mistas nos seus cálculos; (iii) os alunos adequam progressivamente as suas estratégias aos números envolvidos nos problemas, embora nem todos tenham evoluído ao mesmo ritmo; (iv) o ambiente de aprendizagem parece ter influenciado a utilização de estratégias de cálculo mais eficientes, concretamente no uso da compensação (N10C); (v) nas tarefas com contexto os alunos denotam um maior conhecimento acerca das relações entre as operações, recorrendo diversas vezes à operação inversa, o que não é evidenciado nas expressões numéricas, nas quais o sinal de operação influenciou as resoluções.The main aim of this study is to understand which mental computation strategies are used by students in the 2nd year of primary when resolving addition and subtraction exercises with natural numbers. This study specifically characterizes the strategies used by these students when they resolve addition and subtraction tasks, their progress, the difficulties evidenced and the influence of context in the selection of strategies. The theoretical framework is organized into three areas: (i) number sense; (ii) mental computation; (iii) problem solving; and (iv) learning environment. The study follows the interpretative paradigm and a qualitative approach, having the case study as design, based on the development of a learning experience. The participants are five students in the 2nd year of primary in the class I taught in the 2010/2011 school year. The collection of data includes the student records regarding problem solving, as well as video and audio recordings and field notes. The learning experience lasted eight weeks and involved a weekly problem solving task and two chain calculations. The conclusions of this study reveal that: (i) students use a wide range of strategies and that these are related to the meanings of the problems; (ii) there are students who use mixed strategies in their calculations; (iii) students progressively adapt their strategies to the numbers involved in the problems, although not all of them progressed at the same rhythm; (iv) the learning environment seems to have influenced the use of more efficient mental computation strategies, concretely in the use of compensation (N10C); (v) in the tasks that had a context students showed more understanding about the relationships between operations, resorting to inverse operation several times. This does not happen, however, in numerical expressions, in which the signal operation influenced the resolution