University of Minho , 1993
The search for a new high-level and particular programming language was the main subject of this thesis. This language should allow the programming of a system based on an associative processor array (GLiTCH) oriented towards real time image processing. Aiming the goal, this work shows a functional analysis of the GLiTCH system, paying attention to his special caracteristics: his superscalar nature and his pipeline levels. The GLiTCH simulator was, also included, in this analysis. The idea was to have his language as the starting point for the new language. After this, it shows why the simulator's language is not suitable to program the real system, and presents the new language. For trying it out and supporting it, a compiler was build. There are several aproaches to writting a compiler. The author used a specification with Attribute Grammars. All the compiler is specified using attribute grammars, wich allowed his implementation with a tool called {\sf Synthesizer Generator} (SGEN). SGEN is a tool that having an input specification produces a programming environment with incremental compilation for the specified language. Solutions for some problems like address generation, symbol table management and superscalar code generation are presented in a high level specification. The final product of this thesis can bee seen as a prototype of a program development environment for the GLiTCH system. It has two main parts, a structured syntax directed editor and an incremental compiler for the new language proposed by the author.
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in 1st International Meeting on Vector and Paralell Processing, 1993
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in Conferência Nacional WWW - Informação Multimédia na Internet, 1995
Neste artigo discute-se o uso de alguns serviços da Internet na gestão pedagógica de um grupo de disciplinas afins de diferentes cursos da Universidade do Minho (UM). Essa decisão, entre outras inúmeras e interessantes vantagens que trouxe e que serão aqui mencionadas, veio diminuir a distância física entre o docente e o aluno (que no caso concreto da UM se verifica devido à existência de dois pólos em cidades diferentes). Descreve-se, assim, a utilização de uma mailing list, que funciona como um fórum de discussão de todos os assuntos relacionados com a respectiva disciplina, a evolução para a utilização do WWW, a fim de se disponibilizar diversa informação numa página da disciplina, e fazem-se algumas considerações sobre usos futuros. A experiência, mesmo não sendo particularmente inovadora no campo tecnológico da Internet, mostrou-se curiosa e importante pelos efeitos sociais e pedagógicos que acrescentou ao seu objectivo inicial de instrumento de gestão. Por uma questão de coerência com a postura técnica (no âmbito da especificação formal) do grupo responsável pelo conjunto de disciplinas onde foi feita a experiência em narração, conclui-se esta comunicação defendendo o uso de gramáticas de atributos para descrever com rigor a estrutura das páginas a montar em WWW.
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in TWLT10 - Algebraic Methods in Language Processing - AMiLP95, 1995
It is becoming normal that a document should serve several purposes. However, the majority of available text processors is purpose-oriented, reducing the necessary flexibility and reusability of documents. Some waste of time arises from adapting the same text to each different purpose, when this task could be done automatically (from the first version of the document) with an appropriate system. This communication highlights the guidelines to build a system to solve the above problem. Such a system should be an algebraic based environment and provide facilities for: Document type definitions; Definition of Function over document types; Document definitions as algebraic terms. This approach (rooted in the tradition of construtive algebraic specification models ), will allow for an homogeneous environment to deal with operations such as merging documents, converting formats, extracting portions of documents, and some other unusual operations like mail reply and literate programming. We intend to build on camila (a specification language and prototyping environment developed at Universidade do Minho, by the Computer Science group) developing the above mentioned system as one of its extensions.
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Computing Systems in Engineering , 1995
Volume: 6 ; Number: 4/5 ; Pages: 401-408
The prototype of a heterogeneous architecture is currently being built. The architecture is aimed at video-rate computing and is based on a message passing MIMD topology at the top level --- transputer based --- and on VLSI associative processor arrays (APA, SIMD structure) for low level image processing tasks. The APA structure is implemented through a set of 4 VLSI chips (GLiTCH) containing 64 1-bit processing elements each. This communication addresses some issues concerning the implementation of the first prototype, namely those related to: --the design and integration of the APA controller unit, which provides the required interface between the APA, the MIMD topology and the video image interface; --the evaluation of the GLiTCH chip through an emulator based on transputers and fast programmable devices; the emulator was designed to be flexible enough to evaluate later modifications to the GLiTCH design; --the design of an integrated set of software development tools containing a structured editor -- syntax oriented, with a visual interface/programming interface--and a cross compiler and debugger.
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in Workshop: David - Document Processing and SGML, Braga, Portugal, 1996
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in SGML'96: Celebrating a decade of SGML, 1996
SGML introduced DTD idea to formally describe document syntax and structure. One of its main characteristics is the fact of being purely declarative and fully independent of the future document's processing (typesetting, formatting, translation/transformation). In this context, SGML has become the international standard to be followed. Sooner or later, a document has to be processed. In order to do that we need to associate semantics to the document's structure. In a compiler context, normally we separate semantics in two, static and dynamic. Establishing a parallelism with document processing, we can think of the document's decorated tree (as recognized by an SGML analyzer) as representing the static semantics and document's tree transformation as dynamic semantics. Pursuing this idea, we will present and discuss a study of the relationship between SGML, DAST (Decorated Abstract Syntax Tree), and Algebraic Specification, in order to better understand how to formally process documents and how to specify and build generic document processing tools.
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in Simpósio Brasileiro de Linguagens de Programação, 1997
Resumo: Este documento descreve a especificação e implementação do ambiente INES. A premissa do projecto foi a aplicação de técnicas e ferramentas tradicionalmente usadas na compilação e no universo das linguagens de programação ao processamento de documentos. Assim, surgiu INES, um ambiente para construção assistida de editores estruturados baseados em SGML. Para responder a todo um novo conjunto de necessidades, os documentos têm que estar disponíveis em vários formatos e plataformas. Para que isto seja viável, é necessário que as várias formas de um documento sejam geradas a partir de uma mesma representação inicial. Em 1987, um comité internacional criou um standard para a escrita de documentos que foi designado por SGML --- Standard Generalized Markup Language ---, ficando a ser o standard ISO 8879. Actualmente, há muitos editores de SGML comercialmente disponíveis. Uns foram desenvolvidos de raiz; a outros, que já existiam como processadores de texto, foi-lhes acoplado um módulo com a funcionalidade do SGML. Todos estes editores correm, em batch, o processo de validação do documento em edição; a validação é despelotada após a edição por decisão do utilizador. A nossa ferramenta é um gerador de editores que explora o paradigma de parsing e validação incremental, quer no gerador, quer nos editores gerados. O gerador de editores aceita a sintaxe do SGML para a especificação de um determinado tipo de documento (DTD) e gera um editor, estruturado e dirigido pela sintaxe, para os documentos desse novo tipo. Estes editores (gerados pelo INES) têm algumas vantagens inerentes ao paradigma seguido na sua geração: a validação do texto introduzido é automática e imediata; o utilizador não se perde com os detalhes sintácticos do documento, podendo concentrar-se no seu conteúdo. Abstract: This paper describes the specification and implementation of the development environment INES. The application of programming language technics and tools to document processing was the motivation for this project. INES was the result of that goal pursuit: a development environment for assisted construction of SGML based syntax-directed editors. New needs are rising in document processing world. To be able to cope with these new demands documents should be available in several formats and platforms. The satisfaction of this requirement will only be feasible if all the different formats of a given document were generated automatically from the same representation, that should be a standard. In 1987, SGML was introduced as the standard for document production. To join this standard, the use of a dedicated SGML editor is deeply advised. At present there are plenty of those editors commercially available. Some are simply new products while others are extensions to existing word processors. Most of them run the validation process in batch mode upon user decision. Our environment, INES, is an editor generator that exploits the incremental parsing and validation paradigm. Both the generator and the generated editors follow this principle. The generator accepts the SGML syntax as the specification of a document type definition (DTD) and generates a syntax directed editor for that type of documents. This approach offer some advantages: the structure of a new document is verified at edit time; the user only has to worry about content, not about syntax; the same environment is used both for creating a new editor and for producing new documents.
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in SGML/XML'97 Conference, 1997
Quality Control in Electronic Publications should be one of the major concerns of every project. Big projects try to gather information from a series of different sources: universities, libraries, museums and other scientific or cultural organizations. Collecting and treating information from several different sources raises a very interesting problem: the assurance of quality. Quality in Electronic Publications can be reflected in several forms, from the visual aspects of the interface and linguistic/literary ones to the correctness of data. We are concerned with the lowest boundary of this spectrum, correctness of data. With SGML we can solve a small part of the problem, structural correctness. SGML provides a nice way to structure documents keeping a complete separation between structure (syntax) and typesetting. Today there are lots of editors and environments that can assist the user producing well-formed SGML documents (validating their structure). But, there is clearly a lack for content validation. There are situations where pre-conditions over the information being introduced should be enforced in order to prevent the user from introducing erroneous data; we shall call this process data semantics validation. In SGML is not possible to implement this process. We will discuss an adaptation of the SGML syntax that will enable us to express constraints to allow some semantic validation when authoring. Furthermore, we will propose a new SGML processing model capable of dealing with this extension. This model will be built extending the existing one. So, we will not restrict any SGML capability, instead we will add new ones. Both, the SGML extension and the model extension, will be defined and implemented resorting to algebraic specification (SET theory and functional programming).
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in Museums and the Web 1998, 1998
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in SGML98 Europe, 1998
In most specific SGML applications, DTDs aren't enough to express what the designer had in mind. SGML is very good for structure specification. But, sometimes this structure is very loose, gives too much freedom to the user creating a margin for errors. The solution is constraining that structure according to the final document type purposes. This way the user (who writes the documents according to that DTD) will not have full control of his data; he will be enforced to obey certain domain range limitations or certain information relationships. In this paper we will discuss the way we can do or can not do this inside SGML applications (SGML capacity to host constraints). We will discuss ways of associating a constraint language to the SGML model. Furthermore we will try to define the scope of that language. In the end, what we are trying to do is to add a new semantic validation process to the SGML authoring and processing model. We will present also several case studies where the absence of semantic validation could be quite tragic. Concluding this paper we will present a simple solution that implements the discussed constraint language and puts it to work with existing SGML applications (our case studies).
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in Workshop internacional Informação e documentos de arquivo em ambientes digitais, Porto - Portugal, 1998
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in IX encontro nacional de Museus e Autarquias, Loures - Portugal, 1998
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in Terceiro Encontro Nacional para a Qualidade nas tecnologias de informação e comunicação, Guimarães - Portugal, 1998
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in Markup Technologies 98, 1998
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in Theoretical Computer Science: algorithms, automata, complexity and games, 1998
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in Quatic 98: III Encontro Nacional para a Qualidade nas Tecnologias da Informação e Comunicação, 1998
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Markup Languages: theory and practice , 1998
Volume: 1
Quality Control in Electronic Publications should be one of the major concerns of everyone who is managing a project. Big projects, like digital libraries, try to gather information from a series of different sources: libraries, museums, universities, and other scientific or cultural organizations. Collecting and treating information from several different sources raises very interesting problems, one being the assurance of quality. Quality in Electronic Publications can be reflected in several forms, from the visual aspects of the interface and linguistic/literary ones to the correctness of data. With SGML we can solve part of the problem, structural/syntactic correctness. SGML provides a nice way to specify the structure of documents keeping a complete separation between structure (syntax) and typesetting. Today there are lots of editors and environments that can assist the user producing well-formed and valid SGML documents (validating their structure). However, it still gives the user too much freedom. The user has full control of the data being introduced, creating a margin for errors. In this context there are situations where pre-conditions over the information being introduced should be enforced in order to prevent the user from introducing erroneous data; we shall call this process data semantics validation. The idea is to constrain the values of some structural elements of a document according to its final purpose. This way the user (who writes the documents according to that DTD) will not have full control of his data; he will be forced to obey certain domain range limitations or certain information relationships. SGML does not have the necessary constructs to implement this extra validation task. In this paper we will present and discuss ways of associating a constraint language to the SGML model. We will present the steps towards the implementation of that language. In the end, we present a new SGML authoring and processing model which has an extra validation task: semantics validation. Along the paper we will show some case studies that could have their quality improved with this new working schema.
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in XML Europe'99, 1999
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in Digital Resources for the Humanities - DRH99, 1999
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