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Publicações

Publicações por CSE

2016

Incremental Modular Testing for AOP

Autores
Restivo, A; Aguiar, A; Moreira, A;

Publicação
ICSOFT-PT: PROCEEDINGS OF THE 11TH INTERNATIONAL JOINT CONFERENCE ON SOFTWARE TECHNOLOGIES - VOL. 2

Abstract
By designing systems as sets of modules that can be composed into larger applications, developers unleash a multitude of advantages. The promise of AOP (Aspect-Oriented Programming) is to enable developers to organize crosscutting concerns into separate units of modularity making it easier to accomplish this vision. However, AOP does not allow unit tests to be untangled, which impairs the development of properly tested independent modules. This paper presents a technique that enables developers to encapsulate crosscutting concerns using AOP and still be able to develop reusable unit tests. Our approach uses incremental testing and invasive aspects to modify and adapt tests. The approach was evaluated in a medium scale project with promising results. Without using the proposed technique, due to the presence of invasive aspects, some unit tests would have to be discarded or modified to accommodate the changes made by them. This would have a profound impact on the overall modularity and, in particular, on the reusability of those modules. We will show that this technique enables proper unit tests that can be reused even when coupled with aspect-oriented code.

2016

Presence in Virtual Environments: Objective Metrics vs. Subjective Metrics - A Pilot Study

Autores
Melo, M; Rocha, T; Barbosa, L; Bessa, M;

Publicação
2016 23RD PORTUGUESE MEETING ON COMPUTER GRAPHICS AND INTERACTION (EPCGI)

Abstract
The sense of presence and cybersickness are keyfactors to have into account when referring to Virtual Environments (VE). To achieve high levels of presence and minimize cybersickness, it is important to ensure that the user's stimulation is coherent with the contents that are being delivered. In this paper, it is presented a pilot study addressing the usage of both objective and subjective metrics to measure the sense of presence and cybersickness in VE in order to study possible correlations between these two evaluation approaches. On top of that, the pilot study includes two body positions to allow evaluating if the stimulation of the vestibular study has impact on the sense of presence and cybersickness. To evaluate presence and cybersickness, it was developed a VE that consists in a hill where participants ride a bicycle. To broaden the scope of the study, there were studied two body positions: standing and sitting on the bicycle. The equipment EMOTIV epoc+ was used to register the objective metrics. The subjective metrics were registered using the Igroup Presence Questionnaire (IPQ) and the Simulator Sickness Questionnaire (SSQ). To complement the collected data, the levels of fatigue and stress before and after the experience were also registered through self-evaluation. Results show that objective metrics Interest and Stress and the subjective metrics Realism, Fatigue and Stress have a positive interaction regarding the sense of presence. Results further suggest that there is a positive interaction between the objective metric Focus and the subjective metric Involvement.

2016

SafeRegions: Performance evaluation of multi-party protocols on HBase

Autores
Pontes, R; Maia, F; Paulo, J; Vilaca, R;

Publicação
2016 IEEE 35TH INTERNATIONAL SYMPOSIUM ON RELIABLE DISTRIBUTED SYSTEMS WORKSHOPS (SRDSW)

Abstract
On-line applications and services are now a critical part of our everyday life. Using these services typically requires us to trust our personal or company's information to a large number of third-party entities. These entities enforce several security measures to avoid unauthorized accesses but data is still stored on common database systems that are designed without data privacy concerns in mind. As a result, data is vulnerable against anyone with direct access to the database, which may be external attackers, malicious insiders, spies or even subpoenas. Building strong data privacy mechanisms on top of common database systems is possible but has a significant impact on the system's resources, computational capabilities and performance. Notably, the amount of useful computation that may be done over strongly encrypted data is close to none, which defeats the purpose of offloading computation to third-party services. In this paper, we propose to shift the need to trust in the honesty and security of service providers to simply trust that they will not collude. This is reasonable as cloud providers, being competitors, do not share data among themselves. We focus on NoSQL databases and present SafeRegions, a novel prototype of a distributed and secure NoSQL database that is built on top of HBase and that guarantees strong data privacy while still providing most of HBase's query capabilities. SafeRegions relies on secret sharing and multiparty computation techniques to provide a NoSQL database built on top of multiple, non-colluding service providers that appear as a single one to the user. Strikingly, service providers, individually, cannot disclose any of the user's data but, together, are able to offer data storage and processing capabilities. Additionally, we evaluate SafeRegions exposing performance trade-offs imposed by security mechanisms and provide useful insights for future research on performance optimization.

2016

A Bot Spooler Architecture to Integrate Virtual Worlds with E-learning Management Systems for Corporate Training

Autores
Morgado, L; Paredes, H; Fonseca, B; Martins, P; Almeida, A; Vilela, A; Peixinho, F; Santos, A;

Publicação
JOURNAL OF UNIVERSAL COMPUTER SCIENCE

Abstract
Joining efforts of academic and corporate teams, we developed an integration architecture - MULTIS - that enables corporate e-learning managers to use a Learning Management System (LMS) for management of educational activities in virtual worlds. This architecture was then implemented for the Formare LMS. In this paper we present this architecture and concretizations of its implementation for the Second Life Grid/OpenSimulator virtual world platforms. Current systems are focused on activities managed by individual trainers, rather than groups of trainers and large numbers of trainees: they focus on providing the LMS with information about educational activities taking place in a virtual world and/or being able to access within the virtual world some of the information stored in the LMS, and disregard the streamlining of activity setup and data collection in multi-trainer contexts, among other administrative issues. This architecture aims to overcome the limitations of existing systems for organizational management of corporate e-learning activities.

2016

Exploring a Large News Collection Using Visualization Tools

Autores
Devezas, T; Devezas, JL; Nunes, S;

Publicação
Proceedings of the First International Workshop on Recent Trends in News Information Retrieval co-located with 38th European Conference on Information Retrieval (ECIR 2016), Padua, Italy, March 20, 2016.

Abstract
The overwhelming amount of news content published online every day has made it increasingly difficult to perform macro-level analysis of the news landscape. Visual exploration tools harness both computing power and human perception to assist in making sense of large data collections. In this paper, we employed three visualization tools to explore a dataset comprising one million articles published by news organizations and blogs. The visual analysis of the dataset revealed that 1) news and blog sources evaluate very differently the importance of similar events, granting them distinct amounts of coverage, 2) there are both dissimilarities and overlaps in the publication patterns of the two source types, and 3) the content's direction and diversity behave differently over time. Copyright © 2016 for the individual papers by the paper's authors.

2016

Exploring educational immersive videogames: an empirical study with a 3D multimodal interaction prototype

Autores
Alves Fernandes, LMA; Matos, GC; Azevedo, D; Nunes, RR; Paredes, H; Morgado, L; Barbosa, LF; Martins, P; Fonseca, B; Cristovao, P; de Carvalho, F; Cardoso, B;

Publicação
BEHAVIOUR & INFORMATION TECHNOLOGY

Abstract
Gestural interaction devices emerged and originated various studies on multimodal human-computer interaction to improve user experience (UX). However, there is a knowledge gap regarding the use of these devices to enhance learning. We present an exploratory study which analysed the UX with a multimodal immersive videogame prototype, based on a Portuguese historical/cultural episode. Evaluation tests took place in high school environments and public videogaming events. Two users would be present simultaneously in the same virtual reality (VR) environment: one as the helmsman aboard Vasco da Gama's fifteenth-century Portuguese ship and the other as the mythical Adamastor stone giant at the Cape of Good Hope. The helmsman player wore a VR headset to explore the environment, whereas the giant player used body motion to control the giant, and observed results on a screen, with no headset. This allowed a preliminary characterisation of UX, identifying challenges and potential use of these devices in multi-user virtual learning contexts. We also discuss the combined use of such devices, towards future development of similar systems, and its implications on learning improvement through multimodal human-computer interaction.

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