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Publications

Publications by HASLab

2006

A framework for point-free program transformation

Authors
Cunha, A; Pinto, JS; Proenca, J;

Publication
IMPLEMENTATION AND APPLICATION OF FUNCTIONAL LANGUAGES

Abstract
The subject of this paper is functional program transformation in the so-called point-free style. By this we mean first translating programs to a form consisting only of categorically-inspired combinators, algebraic data types defined as fixed points of functors, and implicit recursion through the use of type-parameterized recursion patterns. This form is appropriate for reasoning about programs equationally, but difficult to actually use in practice for programming. In this paper we present a collection of libraries and tools developed at Minho with the aim of supporting the automatic conversion of programs to point-free (embedded in Haskell), their manipulation and rule-driven simplification, and the (limited) automatic application of fusion for program transformation.

2006

Lecture Note in Computer Science (including subseries Lecture Note in Artificial Intelligence and Lecture Note in Bioinformatics): Preface

Authors
Lammel, R; Saraiva, J; Visser, J;

Publication
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

Abstract

2006

Accessibility and visually impaired users

Authors
Fernandes, AR; Pereira, JR; Campos, JC;

Publication
Enterprise Information Systems VI

Abstract
Internet accessibility for the visually impaired community is still an open issue. Guidelines have been issued by the W3C consortium to help web designers to improve web site accessibility. However several studies show that a significant percentage of web page creators are still ignoring the proposed guidelines. Several tools are now available, general purpose, or web specific, to help visually impaired readers. But is reading a web page enough? Regular sighted users are able to scan a web page for a particular piece of information at high speeds. Shouldn't visually impaired readers have the same chance? This paper discusses some features already implemented to improve accessibility and presents a user feedback report regarding the AudioBrowser, a talking browser. Based on the user feedback the paper also suggests some avenues for future work in order to make talking browsers and screen readers compatible.

2006

Ambience and mobility

Authors
Doherty, GJ; Du Bousquet, L; Campos, JC; El Atifi, EM; Falquet, G; Massink, M; Santoro, C;

Publication
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

Abstract

2006

Supporting resource-based analysis of task information needs

Authors
Campos, JC; Doherty, GJ;

Publication
INTERACTIVE SYSTEMS: DESIGN, SPECIFICATION, AND VERIFICATION

Abstract
We investigate here an approach to modelling the dynamic information requirements of a user performing a number of tasks, addressing both the provision and representation of information, viewing the information as being distributed across a set of resources. From knowledge of available resources at the user interface, and task information needs we can identify whether the system provides the user with adequate support for task execution. We look at how we can use tools to help reason about these issues, and illustrate their use through an example. We also consider a full range of analyses suggested using this approach which could potentially be supported by automated reasoning systems.

2006

Type-safe two-level data transformation

Authors
Cunha, A; Oliveira, JN; Visser, J;

Publication
FM 2006: FORMAL METHODS, PROCEEDINGS

Abstract
A two-level data transformation consists of a type-level transformation of a data format coupled with value-level transformations of data instances corresponding to that format. Examples of two-level data transformations include XML schema evolution coupled with document migration, and data mappings used for interoperability and persistence. We provide a formal treatment of two-level data transformations that is type-safe in the sense that the well-formedness of the value-level transformations with respect to the type-level transformation is guarded by a strong type system. We rely on various techniques for generic functional programming to implement the formalization in Haskell. The formalization addresses various two-level transformation scenarios, covering fully automated as well as user-driven transformations, and allowing transformations that are information-preserving or not. In each case, two-level transformations are disciplined by one-step transformation rules and type-level transformations induce value-level transformations. We demonstrate an example hierarchical-relational mapping and subsequent migration of relational data induced by hierarchical format evolution.

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