Nuno Valero Ribeiro

Abstracts of publications

Papers

An Applet Based Query Tool

With the WWW exponential development there is a growing need and demand for applications which integrate information from existing databases in one single point of access like a common browser. This paper describes an applet based 3-tier client/server Java application, which enables Internet users to easily access and query, via JDBC application programming interface, a remote database using a HTML page.
[BibTeX ref., PostScript zipped (63 Kb)].

An evolutionary multi-agent system for simulating e-commerce markets


This paper describes a multi-agent system used for simulating a generic e-trading market. The simulated market is imagined to be on the Internet. Four different types of agents are used in our system: clients, producers, distributors and mediators --- for clients and  producers. The simulation starts with an initially given market which evolves under various assumptions about mediators. Mediation services support the following aspects: brokerage, billing, delivery and connectivity. Each mediator has a profile based on its degree of greediness, effort and speed. The evolution of the system is controlled by the individual fitness of the mediator agents. Those that profit from their negotiations stay alive, while others die. The most successful mediators are cloned and populate the system. Thus, the system evolution helps with identifying the appropriate mediator profiles. Internal implementation choices are discussed and analyzed. Results from an experiment using a typical market scenario are presented to illustrate the system in use.
 

[BibTeX ref., PostScript zipped (137 Kb)].

Campus Personal Computing: uses, evolution, and new perspectives


This paper first presents a survey of campus computing projects describing in detail the aspects that matter the most. These projects have the common goal of integrating Personal Computers in academic regular activities. From this description it becomes clear that almost all of these projects adopt standard PC platforms, that offer a common set of installed software applications, recommended by the institution. Currently, a significant portion of these initiatives adopted \emph{mobile} PC platforms as the platform of choice.
It is then shown that further developments are still possible if mechanisms for accessing the execution of heterogeneous applications are transparently given. This system concept---universal access to applications---is discussed together with its main technical problems. Such a system design---SDUA---, for allowing users of an academic campus universal access to applications, is then presented. The main objective of SDUA is to provide their users access to its offered applications, from any computer, in a uniform fashion. Finally, SDUA users, operational and functional requirements, and principal services are identified.
 

[BibTeX ref., PostScript zipped (122 Kb)]

 

An E-learning Platform Concept

In this paper we describe an e-learning platform concept---a new approach for the learning/teaching activity in an academic environment. Our perspective of e-learning is based on the organizational reality which involves the learning/teaching activity, therefore, adapted to the physical environment and human relations present in real schools.
We envision three type of users---students, teachers and maintainers---their roles and levels of interaction with the platform being outlined. Three main functional requirements are identified, underling the platform concept, namely: (a) coordination---of a group of users under the baton of one user; (b) communication---between different users; (c) knowledge transfer---from the teacher to his students. The platform implementation is undergoing and it will be tested in three courses. Future directions for e-learning and the proposed platform are discussed focusing on the integration of tutoring facilities and on the e-school concept.
 
[BibTeX ref., PDF zipped (77 Kb)]

Thesis

A platform for Universal Access to Applications

The thesis studies the requirements, functionalities, architecture, and implementation of a distributed system, for allowing universal access to the applications found in an academic campus environment. The motivation of such system is to provide, from a single (mobile)  computer at an arbitrary physical location, transparent uniform access to the execution of a heterogeneous set of applications which typically are available in different machines in distinct geographical locations and require their users to be physically present at those locations. Two surveys are then introduced: one about personal computer use in academic campuses and another about current existing technologies for universal execution of applications. The requirements of such system are then established. Consequently, the definition of its functional modules, their interactions and distribution is given. Possible technologies for distributed object oriented application
support are analyzed foreseeing the implementation of the conceived system. Finally, a description about the key modules identified for universal access to applications service developed is given. Keywords: Personal Campus Computing; Universal Access to
Applications; Analysis and Design of Distributed Systems; Modeling Methodologies; Distributed Object Oriented Applications Support;
Object Oriented Analysis and Design; Ubiquitous Applications.
[BibTeX ref., PostScript zipped (9.069(!) Kb, portuguese only)]
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Last update: March 2001.
Comments and suggestions to nribeiro@est.ips.pt.