2014
Authors
Abreu, PH; Xavier, J; Silva, DC; Reis, LP; Petry, M;
Publication
SCIENTIFIC WORLD JOURNAL
Abstract
Nowadays, there are many technologies that support location systems involving intrusive and nonintrusive equipment and also varying in terms of precision, range, and cost. However, the developers some time neglect the noise introduced by these systems, which prevents these systems from reaching their full potential. Focused on this problem, in this research work a comparison study between three different filters was performed in order to reduce the noise introduced by a location system based on RFID UWB technology with an associated error of approximately 18 cm. To achieve this goal, a set of experiments was devised and executed using a miniature train moving at constant velocity in a scenario with two distinct shapes-linear and oval. Also, this train was equipped with a varying number of active tags. The obtained results proved that the Kalman Filter achieved better results when compared to the other two filters. Also, this filter increases the performance of the location system by 15% and 12% for the linear and oval paths respectively, when using one tag. For a multiple tags and oval shape similar results were obtained (11-13% of improvement).
2014
Authors
Silva, DC; Abreu, PH; Reis, LP; Oliveira, E;
Publication
INFORMATION SCIENCES
Abstract
The work described in this paper is part of the development of a framework to support the joint execution of cooperative missions by a group of robotic vehicles, in a simulated, augmented or real environment. Such framework brings forward the need for formal languages in which to specify the group of vehicles that compose a team; the scenario in which they will operate; and the definition of the mission to be performed (surveillance, pollution detection, search and rescue operations, and so on). This paper presents the Mission Description Language (MDL), a XML dialect that describes the specifics of a mission to be performed by a team of autonomous vehicles. The MDL definition decomposes a mission into a number of possibly dependent phases and uses high-level concepts that facilitate the specification of a mission by both experts and non-experts. The dialect was defined using XML Schema, with all the required information being integrated in the definition. An interface was developed and incorporated into the framework, as to allow for the creation and edition of XML files following the defined schema. Once the information is correctly specified, it can be used in the framework, thus facilitating the process of mission specification and deployment. A survey answered by both practitioners and researchers shows that the degree of satisfaction with MDL is elevated (the overall evaluation of MDL achieved a 3.97 score (out of 5), with 82.05% of the answers being equal to or above 4); also, the usability of the interface was evaluated, having achieved a score of 82.9 in the SUS scale. These results imply that MDL is flexible enough to represent several types of missions, through a user-friendly interface.
2014
Authors
Cravo, J; Almeida, F; Abreu, PH; Reis, LP; Lau, N; Mota, L;
Publication
DATA & KNOWLEDGE ENGINEERING
Abstract
One of the research topics on multi-agent systems focuses on the development of mechanisms such as plans to empower a team of agents to cooperate in order to perform complex tasks. In many cases, the definition of these plans are based on a specific and rather complex grammar and stored in structured text files. In the context of the 2D simulated Robotic Soccer domain, a set-play language was proposed to coordinate the execution of teammates' behaviors to improve a team's overall performance. The process of manually writing set-play definitions is hazardous and can benefit from the use of a graphical tool to reach new users and allow typical users to become more productive. This work presents such a tool for which several experiments were run to measure its usability with forty two users by having them perform a set of tasks for which their execution time, number errors and satisfaction were recorded. The tool reduced the previous average time required to completely define a set-play by 90% and enabled even non-expert users to use it Moreover, users were on average satisfied with SPlanner having ranked it with a score of 77 (out of 100) using a System Usability Scale questionnaire.
2014
Authors
Abreu, PH; Amaro, H; Silva, DC; Machado, P; Abreu, MH;
Publication
IFMBE Proceedings
Abstract
The prediction of overall survival in patients has an important role, especially in diseases with a high mortality rate. Encompassed in this reality, patients with oncological diseases, particularly the more frequent ones like woman breast cancer, can take advantage of a very good customization, which in some cases may even lead to a disease-free life. In order to achieve this customization, in this work a comparison between three algorithms (evolutionary, hierarchical and k-medoids) is proposed. After constructing a database with more than 800 breast cancer patients from a single oncology center with 15 clinical variables (heterogeneous data) and having 25% of the data missing, which illustrates a real clinical scenario, the algorithms were used to group similar patients into clusters. Using Tukey's HSD (Honestly Significant Difference) test, from both comparison between k-medoids and the other two approaches (evolutionary and hierarchical clustering) a statistical difference were detected (p- value < 0.0000001) as well as for the other comparison (evolutionary versus hierarchical clustering) - p-value = 0.0061354 - for a significance level of 95%. The future work will consist primarily in dealing with the missing data, in order to achieve better results in future prediction. © 2014, Springer International Publishing Switzerland.
2014
Authors
Simoes, D; Abreu, PH; Silva, DC;
Publication
NEW PERSPECTIVES IN INFORMATION SYSTEMS AND TECHNOLOGIES, VOL 2
Abstract
Along with the evolution of the Internet and its ever-increasing use, a significant trend to develop solutions to provide information is noticeable. This scenario increases information decentralization in certain contexts. Nowadays, information regarding music is available online in several online locations. In this context, this paper reports on the development of a web platform that centralizes existing information regarding events, retrieving other contextually related data available. Validated with both information retrieval quality and interface usability metrics, this project attained a more effective and complete concert search service according to the data provided to the user. It has revealed itself capable of retrieving information on more events, when compared to other platforms without a data centralization approach. According to the usability survey results attained, such as an 89 SUS scale score, it was proved that the developed service is provided with a simple and intuitive interface as well.
2014
Authors
Pereira, F; Silva, DC; Abreu, PH; Pinho, A;
Publication
NEW PERSPECTIVES IN INFORMATION SYSTEMS AND TECHNOLOGIES, VOL 2
Abstract
The growing use of smartphones has revolutionized the way people live, fostering the use of mobile application in the most diverse situations. These applications take advantage of the mobile device's capabilities to provide the user with useful and contextualized information, being equipped with increasingly intuitive interfaces, and offering richer contents in an attractive manner. Augmented reality emerges as one of the technologies that can be used in these applications, allowing for an improved user experience. This paper describes a tourism-oriented mobile application, in this case to be used in a botanical garden, which uses current mobile device's capabilities to provide the visitor with several ways to obtain the desired information. The results obtained from this application are shown, including images of the implemented features, and highlighting the results related to the use of augmented reality.
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