A type system for access control in an object-oriented language

Trabalho apresentado no âmbito do Mestrado em Engenharia Informática, como requisito parcial para obtenção do grau de Mestre em Engenharia Informática

Core language for web applications

Trabalho apresentado no âmbito do Mestrado em Engenharia Informática, como requisito parcial para obtenção do grau de Mestre em Engenharia Informática

Solució global per la gestió de dades d'empleat mitjançant J2ME/J2EE.

Aquest treball final de carrera es basa en l'anàlisi, disseny i implementació d'una solució per comunicar un empleat i la seva empresa per tal de gestionar informació i dades de l'empleat com poden ser: la nòmina, el full d'hores, el full de despeses i la consulta i sol·licitud de vacances.

Automatització d'enquestes

La realització d'aquest projecte genererà un aplicatiu que permetrà la realització d'enquestes telefòniques a usuaris predefinits, automatització la execució de qüestionaris parametritzats amb XML, i gravant aquestes respostes en local i en una base de dades remota.

Aplicació web per gestió de tornejos d'escacs amb J2EE

L'aplicació consisteix en un programa web que des d'un navegador ens permet realitzar una sèrie de consultes i de gestions contra una base de dades de tornejos d'escacs. Les gestions i consultes variaran segons el rol d'usuari sigui administrador, gestor o usuari Internet. Així, l'aplicació consta d'un servidor, una base de dades, unes classes entitat Java que treballaran a la capa de model per fer els canvis a la Base de dades, unes pàgines html i jsp, que estaran a la capa de vista, uns fitxers de configuració .xml i uns fitxers .java que actuaran a la capa de control. Els rols s'han implantat a nivell de servidor, amb una pàgina de login, i segons el rol escollit, es tindrà accés a una carpeta (zona) o altra.

Formalizing argumentative reasoning in a possibilistic logic programming setting with fuzzy unification

Possibilistic Defeasible Logic Programming (P-DeLP) is a logic programming language which combines features from argumentation theory and logic programming, incorporating the treatment of possibilistic uncertainty at the object-language level. In spite of its expressive power, an important limitation in P-DeLP is that imprecise, fuzzy information cannot be expressed in the object language. One interesting alternative for solving this limitation is the use of PGL+, a possibilistic logic over Gödel logic extended with fuzzy constants. Fuzzy constants in PGL+ allow expressing disjunctive information about the unknown value of a variable, in the sense of a magnitude, modelled as a (unary) predicate. The aim of this article is twofold: firstly, we formalize DePGL+, a possibilistic defeasible logic programming language that extends P-DeLP through the use of PGL+ in order to incorporate fuzzy constants and a fuzzy unification mechanism for them. Secondly, we propose a way to handle conflicting arguments in the context of the extended framework.

A logic programming framework for possibilistic argumentation: formalization and logical properties

In the last decade defeasible argumentation frameworks have evolved to become a sound setting to formalize commonsense, qualitative reasoning. The logic programming paradigm has shown to be particularly useful for developing different argument-based frameworks on the basis of different variants of logic programming which incorporate defeasible rules. Most of such frameworks, however, are unable to deal with explicit uncertainty, nor with vague knowledge, as defeasibility is directly encoded in the object language. This paper presents Possibilistic Logic Programming (P-DeLP), a new logic programming language which combines features from argumentation theory and logic programming, incorporating as well the treatment of possibilistic uncertainty. Such features are formalized on the basis of PGL, a possibilistic logic based on G¨odel fuzzy logic. One of the applications of P-DeLP is providing an intelligent agent with non-monotonic, argumentative inference capabilities. In this paper we also provide a better understanding of such capabilities by defining two non-monotonic operators which model the expansion of a given program P by adding new weighed facts associated with argument conclusions and warranted literals, respectively. Different logical properties for the proposed operators are studied

Web Services In Symbian OS

This thesis presents different aspects of Web Services usage in Symbian OS that is an operating system for handheld devices. The practical part of the work was to develop Symbian OS client application for Web Services. It produced four reusable software components. XML enables platform and programming language independent services. Web Services use XML to create standardized message oriented services that are accessed through HTTP. Web Services are moving towards dynamic B2B interaction. Web Services increases the amount of transferred data, which is not desirable in mobile networks where transfer speed is slower than in the traditional networks. However the modern mobile networks are able to transfer the extra payload with reasonable time. XML processing is not a big problem. Web Services can be accessed from the modern mobile devices and they can cut down the development costs.

Context exchange between devices in mobile environment

Context awareness is emerging on mobile devices. Context awareness can be used to improve usability of a mobile device. Context awareness is particularly important on mobile devices due the limitations they have. At first in this work, a literature review on context awareness and mobile environment is made. For aiding context awareness there exist an implementation of a Context Framework for Symbian S60 devices. It provides a possibility for exchanging the contexts inside the device between the client applications of the local Context Framework. The main contribution of this thesis is to design and implement an enhancement to the S60 Context Framework for providing possibility to exchange context over device boundaries. Using the implemented Context Exchange System, the context exchange is neither depending on the type of the context nor the type of the client. In addition, the clients and the contexts can reside on any interconnected device. The usage of the system is independent of the programming language since in addition to using only Symbian C++ function interfaces it can also be utilized using XML scripts. The Meeting Sniffer application, which uses the Context Exchange System, was also developed in this work. Using this application, it is possible to recognize a meeting situation and suggest device profile change to a user.

Teaching mathematics and programming : new approaches with empirical evaluation

Programming and mathematics are core areas of computer science (CS) and consequently also important parts of CS education. Introductory instruction in these two topics is, however, not without problems. Studies show that CS students find programming difficult to learn and that teaching mathematical topics to CS novices is challenging. One reason for the latter is the disconnection between mathematics and programming found in many CS curricula, which results in students not seeing the relevance of the subject for their studies. In addition, reports indicate that students' mathematical capability and maturity levels are dropping. The challenges faced when teaching mathematics and programming at CS departments can also be traced back to gaps in students' prior education. In Finland the high school curriculum does not include CS as a subject; instead, focus is on learning to use the computer and its applications as tools. Similarly, many of the mathematics courses emphasize application of formulas, while logic, formalisms and proofs, which are important in CS, are avoided. Consequently, high school graduates are not well prepared for studies in CS. Motivated by these challenges, the goal of the present work is to describe new approaches to teaching mathematics and programming aimed at addressing these issues: Structured derivations is a logic-based approach to teaching mathematics, where formalisms and justifications are made explicit. The aim is to help students become better at communicating their reasoning using mathematical language and logical notation at the same time as they become more confident with formalisms. The Python programming language was originally designed with education in mind, and has a simple syntax compared to many other popular languages. The aim of using it in instruction is to address algorithms and their implementation in a way that allows focus to be put on learning algorithmic thinking and programming instead of on learning a complex syntax. Invariant based programming is a diagrammatic approach to developing programs that are correct by construction. The approach is based on elementary propositional and predicate logic, and makes explicit the underlying mathematical foundations of programming. The aim is also to show how mathematics in general, and logic in particular, can be used to create better programs.

Developing an introductory object-oriented programming course

The state of the object-oriented programming course in Lappeenranta University of Technology had reached the point, where it required changes to provide better learning opportunities and thus the learning outcomes. Based on the student feedback the course was partially dated and ineffective. The components of the course were analysed and the ineffective elements were removed and new methods were introduced to improve the course. The major changes included the change from traditional teaching methods to reverse classroom method and the use of Java as the programming language. The changes were measured by the student feedback, lecturer’s observations and comparison to previous years. The feedback suggested that the changes were successful; the course received higher overall grade than before.

BDI4JADE: a BDI layer on top of JADE

Several agent platforms that implement the belief-desire-intention (BDI) architecture have been proposed. Even though most of them are implemented based on existing general purpose programming languages, e.g. Java, agents are either programmed in a new programming language or Domain-specific Language expressed in XML. As a consequence, this prevents the use of advanced features of the underlying programming language and the integration with existing libraries and frameworks, which are essential for the development of enterprise applications. Due to these limitations of BDI agent platforms, we have implemented the BDI4JADE, which is presented in this paper. It is implemented as a BDI layer on top of JADE, a well accepted agent platform.

Adaptivity in programming languages

A programming style can be seen as a particular model of shaping thought or a special way of codifying language to solve a problem. An adaptive device is made up of an underlying formalism, for instance, an automaton, a grammar, a decision tree, etc., and an adaptive mechanism, responsible for providing features for self-modification. Adaptive languages are obtained by using some programming language as the device’s underlying formalism. The conception of such languages calls for a new programming style, since the application of adaptive technology in the field of programming languages suggests a new way of thinking. Adaptive languages have the basic feature of allowing the expression of programs which self-modifying through adaptive actions at runtime. With the adaptive style, programming language codes can be structured in such a way that the codified program therein modifies or adapts itself towards the needs of the problem. The adaptive programming style may be a feasible alternate way to obtain self-modifying consistent codes, which allow its use in modern applications for self-modifying code.

Adaptive languages and a new programming style

A programming style can be seen as a particular model of shaping thought or a special way of codifying language to solve a problem. Adaptive languages have the basic feature of allowing the expression of programs which self-modifying through adaptive actions at runtime. The conception of such languages calls for a new programming style, since the application of adaptive technology in the field of programming languages suggests a new way of thinking. With the adaptive style, programming language codes can be structured in such a way that the codified program therein modifies or adapts itself towards the needs of the problem. The adaptive programming style may be a feasible alternate way to obtain self-modifying consistent codes, which allow its use in modern applications for self-modifying code.