João H. Rosa

MUCS: A model for ubiquitous commerce support

The evolution of computing technology and the emergence of wireless networks have contributed to the miniaturization of mobile devices and their increase in power, providing services anywhere and anytime. In this context, new opportunities for technology support have arisen in different areas, for example, education, games and entertainment, automobile, and commerce. We propose a model for ubiquitous commerce support (MUCS). This model uses ubiquitous computing concepts to look for deal opportunities for users who act either as buyers or sellers. This paper also describes two everyday scenarios, in which the MUCS model could be applied, and explains the implemented prototype to be used in them. Finally, we present the results obtained from a practical experiment, which was performed with the participation of users who filled out an evaluation questionnaire.

A management model of learning objects in a Ubiquitous Learning environment

Mobility of users carrying mobile devices with access to wireless networks creates the need to provide uniform and immediate access to information. In this scenario, a new educational model, called Ubiquitous Learning, has been studied. In this model, the educational processes are related to the learners situation, i.e. they are context-aware. This allows the access to educational resources be adapted to the learners profile and context. GlobalEdu is a computing environment which aims at supporting Ubiquitous Learning. This paper presents the GlobalEdu model for content management and an experiment performed to validate it.

ORACON: An adaptive model for context prediction

Abstract Context prediction has been receiving considerable attention in the last years. This research area seems to be the next logical step in context-aware computing, which, until a few years ago, had been concerned more with the present and the past temporal dimensions. Most of research works related to context prediction employ the same algorithm for all cases. We did not find any approach that automatically decides the best prediction method according to the situation. Therefore, we propose the ORACON model. ORACON adapts itself in order to apply the best algorithm to the case. This adaptive behavior is the main contribution of this work and differentiates the proposed model of other related works. Furthermore, ORACON supports other important aspects of ubiquitous computing, such as, context formal representation and privacy. We have built a functional prototype that allowed us to conduct two experiments. The first experiment successfully tested the main functionalities provided by ORACON to support context prediction and privacy aspects. The test used context histories generated with a location database that contains 22 millions chekins across 220,000 users in the location sharing services Foursquare and Twitter. The second experiment assessed the adaptive feature of the ORACON. The test simulated the behavior of 30 users for a period of 30 days, using context histories generated through the Siafu simulator. This tool generates data for the evaluation and the comparison of machine learning methods in mobile context-aware settings. We concluded that ORACON chose the most accurate prediction algorithm in the simulated scenario, proving that the model reached the main contribution sought by this research.

A Multi-Temporal Context-aware System for Competences Management

The evolution of computing technology and wireless networks has contributed to the miniaturization of mobile devices and their increase in power, providing services anywhere and anytime. In this scenario, applications have considered the user’s contexts to make decisions (Context Awareness). Context-aware applications have enabled new opportunities in different areas, for example, education, games and entertainment, commerce, and competence management. In this article, we present MultCComp, a multi-temporal context-aware system for competences management. The main system contribution is to take advantage of the workers’ present and past contexts to help them to develop their competences. We define as multi-temporal context awareness the joint use of workers’ present and past contexts to assist them in the development of their competences. We developed a prototype and conducted two experiments with it in an evaluation environment. The first experiment aimed to demonstrate the system functionalities. It consisted of two evaluation scenarios that were followed by two users. The second experiment focused on evaluating the acceptance of the system. It comprised a scenario that was followed by 21 users, who filled out a questionnaire at the end of the test.

Towards a programming model for context-aware applications

In mobile computing scenarios, users move in different environments and applications can automatically explore their surroundings. This type of context-aware application is an emerging trend, so far not widely disseminated. We believe that the proposal of a programming model specifically designed for the specification of context-aware applications, using general abstractions, will foster a rapidly widespread of such kind of software. In this article, we propose the use of the Holoparadigm (in short Holo) to fill this gap. We created a programming language based on Holo (called HoloL) to demonstrate the strengths of Holoparadigm to develop context-aware applications. The article uses a sample scenario to show the Holos practical aspects related to implementation of context-aware applications. We also present a platform to HoloL (called HoloEnv), composed of a compiler, a virtual machine, and a distributed execution environment. Finally, different performance aspects of the HoloEnvs components were evaluated through experimental results.

A Model to Explore Business Opportunities in Ubiquitous Environments

The mobile and ubiquitous computing has been stimulated by the widespread diffusion of mobile devices, wireless networks, and, more recently, by location systems. In this context, applications are emerging in different areas, such as, education, entertainment, and commerce. The application of the ubiquitous computing in the exploration of business opportunities is called Ubiquitous Commerce. This paper proposes the UbiTrade model, which aims at supporting the ubiquitous commerce. Considering the related works, we can note that the proposed model is the only that allows the user to act either in the supplier role or in the consumer character. In addition, most of the current proposals are restricted to a specific area of business. The UbiTrade does not have this restriction. The model was implemented and its validation was conducted by a group of users. The results indicated the model feasibility, particularly in regard to its most significant contribution, that is, the integration of the support to the roles of supplier and consumer.

Content distribution in trial-aware environments

In mobile computing environments, the tracking of users allows the adaptation of applications to the contexts visited by the user (Context Awareness). In recent years, the use of context information and user profiles is being considered an opportunity to context-aware content management. The improvement and the wide adoption of location systems are stimulating the tracking of users, allowing the use of Trails. A trail is the history of contexts visited by a user during a period. This paper proposes a model for the management of trails and its application in the content management. In this text, it is considered that the Trail-Aware is an evolution of the use of contexts and profiles. The text presents a prototype and its application in an educational environment for the distribution of learning objects using trail-aware.