Adolfo Duran

An algebraic approach to the design of compilers for object-oriented languages

In this paper we describe an algebraic approach to construct provably correct compilers for object-oriented languages; this is illustrated for programs written in a language similar to a sequential subset of Java. It includes recursive classes, inheritance, dynamic binding, recursion, type casts and test, assignment, and class-based visibility, but a copy semantics. In our approach, we tackle the problem of compiler correctness by reducing the task of compilation to that of program refinement. Compilation is identified with the reduction of a source program to a normal form that models the execution of object code. The normal form is generated by a series of correctness-preserving transformations that are proved sound from the basic laws of the language; therefore it is correct by construction. The main advantages of our approach are the characterisation of compilation within a uniform framework, where comparisons and translations between semantics are avoided, and the modularity and extensibility of the resulting compiler.

A Strategy for Compiling Classes, Inheritance, and Dynamic Binding

This paper presents a refinement strategy for the compilation of a subset of Java that includes classes, inheritance, dynamic binding, visibility control, and recursion. We tackle the problem of compiler correctness by reducing the task of compilation to that of program refinement. More specifically, refinement laws are used as compilation rules to reduce the source program to a normal form that models an interpreter running the target code. The compilation process is formalized within a single and uniform semantic framework, where translations or comparisons between semantics are avoided. Each compilation rule can be proved correct with respect to the algebraic laws of the language.

A convergência tecnológica líquida no contexto da sala de aula: um recorte do ensino superior público baiano sob a ótica discente

Este artigo apresenta um modelo para aplicacao de tecnicas de mineracao em dados coletados a partir de avaliacoes da aprendizagem. A partir da proposta, torna-se possivel identificar quais conteudos e em que niveis cognitivos eles foram assimilados pelos aprendizes, permitindo, assim, que estrategicas pedagogicas sejam adequadamente planejadas para grupos de estudantes que apresentem as dificuldades identificadas. Para validar o estudo, sao apresentados tambem os resultados do experimento realizado numa disciplina de Programacao do curso de Licenciatura em Computacao da Universidade de Pernambuco.

Processes of knowledge construction in the classroom mediated by technological convergence: reflections of this emerging scenario

It is remarkable the outbreak in the educational context, of the phenomenon we call technological convergence, in short, characterized by a proliferation and coexistence of mobile cyberinstruments (netbooks, tablets, etc.) and constant flow of information. In this sense, the aim of this paper is to discuss changes in knowledge building processes in the classroom environment, in the context of higher education, mediated by technological convergence. To this end, we developed an exploratory and qualitative research whose investigated object was a postgraduate course. The instruments used to conduct experiments were participant observation, semistructured interviewing and literature review; for the analysis, we used content analysis and triangulation between the cited instruments. The research, with special emphasis on multidisciplinary attentional mechanisms, allowed us to identify and assess relevant aspects of the studied scenario, revealing that the convergence can help to accelerate processes of (collaborative) knowledge building but also raise difficulties.

Abstract specification and formalization of an operating system kernel in Z

One of the mini challenges in software verification related to the Grand Challenge proposed by Tony Hoare concerns the formal specification and verification of an operating system kernel. This paper proposes a simple and correct specification of an OS kernel in Z which simplifies the understanding and verification of operating system components. Our current specification comprises process management, interprocess communication and a POSIX-compliant file system.

PBLOntology: A Domain Ontology with Context Elements for Problem-based Learning.

In education, ontologies have been proved useful for structuring intelligent tutors, collaborative learning, creation of learning models, semantic search for recommendation of learning material, personification and adaption of educational content based on the student’s context. Problem-Based Learning (PBL) is a pedagogical methodology that is regarded as an alternative to traditional learning for skills development. However, the use of web-based technologies to support learning in the PBL methodology is still recent. A systematic review was conducted and it has shown the lack of formal representation of the PBL concepts based on ontology language. Thus, this paper proposes a reference ontology for PBL called PBLOntology, which uses context elements of the methodology. For conception of the ontology, a research was conducted in a computer-engineering course that adopts the PBL methodology. To assess the PBLOntology, we defined relevant criteria regarded as fundamental for ontologies: testing activities and evaluation with experts. Although most of the experts stated that the definitions satisfied or partially satisfied, their feedback allowed us adjust some definitions, improving the ontology.

Uso de dispositivos móveis em sala de aula: uma análise qualitativa de um recorte do ensino superior baiano

Este artigo discute o uso de dispositivos móveis na sala de aula considerando um recorte da realidade universitária baiana. Para tanto, utilizou-se de artefatos da pesquisa qualitativa, buscando adentrar o cotidiano da sala de aula do ponto de vista discente. Ponderando vantagens e desvantagens de tal uso, percebemos que a dispersão é o grande desafio que se põe para professores e estudantes. Porém, isso não significa que para estes últimos tais dispositivos devam ser extintos da sala de aula, mas sim contextualizados de uma melhor forma. Finalmente, também notamos que o uso de dispositivos móveis pouco tem favorecido o processo de construção no âmbito coletivo, diferente do que pode ocorrer na esfera individual.