http://hdl.handle.net/10316/27707 2020-02-26T11:54:14Z 2020-02-26T11:54:14Z Rocha, Fernando Machado Santa, Pedro Jorge Carlos dos Santos Cardoso Pereira, Luís Lucas Roque, Licínio http://hdl.handle.net/10316/87771 2020-02-10T13:48:52Z 2019-10-01T00:00:00Z

Title: Mapping Controls on a 2D User Drawn Racetracks Driving Game - An Usability Assessment Authors: Rocha, Fernando; Machado Santa, Pedro; Jorge Carlos dos Santos Cardoso; Pereira, Luís Lucas; Roque, Licínio Abstract: In this paper, we present the results from an experiment designed to evaluate the user experience of five different control schemes (buttons, steering wheel, joystick, joystick+button and accelerometer-based tilting) in a 2D top-down racing mobile game designed specifically for children. The experiment was conducted with 24 children from ages 6 to 14, both male and female, and with different levels of experience with mobile devices and mobile gaming. We present the results from our observations from the participants’ interaction with the game as well as the results from a questionnaire and interview. Results indicate that the joystick controller provides a better experience than the proposed alternatives to inexperienced players. Author

2019-10-01T00:00:00Z Cardoso, Jorge C.S. Perrotta, André http://hdl.handle.net/10316/87656 2019-09-27T20:31:39Z 2019-01-01T00:00:00Z

Title: A survey of real locomotion techniques for immersive virtual reality applications on head-mounted displays Authors: Cardoso, Jorge C.S.; Perrotta, André Abstract: Locomotion is a fundamental activity in Virtual Reality (VR) and has been the focus of a large body of research since the implementation of the first systems. In real locomotion techniques, users physically move in the real world to affect movement in the Virtual Environment (VE). Real locomotion has been found to perform better than other forms of locomotion for many tasks. To overcome the challenges imposed by restricted physical space, researchers have devised ingenious interaction techniques for real locomotion. In this paper, we present a survey of interaction techniques for real locomotion in VR. Our analysis is focused on the interaction techniques – the combination of devices, user’s actions, and system’s responses. We categorize interaction techniques for real locomotion in VR into: unmediated, warnings, reorientation/resetting, scaling, redirection, and dynamic VE. These categories represent fundamentally different approaches to real locomotion and user action feedback. We further characterize techniques in each of these categories according to category-specific parameters. Finally, it is important to state that this paper was developed with the aim of helping newcomers to the field to understand and implement the techniques here presented.

2019-01-01T00:00:00Z Ribeiro, Bernardete Martins Chen, Ning http://hdl.handle.net/10316/87225 2020-02-11T10:24:25Z 2017-01-01T00:00:00Z

Title: Financial credit risk assessment via learning-based hashing Authors: Ribeiro, Bernardete Martins; Chen, Ning Abstract: With the increasing amount of financial data produced today, the problem of finding the k-nearest neighbors to the query point in high-dimensional space is itself of importance to access the financial credit risk. Binary embeddings are efficient tools of indexing big datasets for financial credit risk analysis. The idea is to find a good hash function such that similar data points in Euclidean space preserve their similarities in the Hamming space for fast data retrieval. By exploring out-of-sample extension to test data it is possible to set forth a go-forward strategy to establish a fast retrieval model of companies' status thereby rendering the stakeholders' evaluation task very efficiently. First, we use semi-supervised learning-based hashing to take into account the pairwise information for constructing the weight adjacency graph matrix needed or building the binarised Laplacian EigenMap. Second, we train a generalised regression neural network (GRNN) to learn the k-bits hash function. Third, the k-bit binary code for the test data is efficiently found in the recall phase. Experimental results on financial data demonstrated the proposed approach showed the applicability and advantages of learning-based hashing to credit risk assessment.

2017-01-01T00:00:00Z Cardoso, Jorge C. S. Figueiredo, Humberto Correia, Virgílio Hipólito http://hdl.handle.net/10316/86951 2020-02-10T13:48:52Z 2018-01-01T00:00:00Z

Title: Digital tools for exploring Roman mosaic Authors: Cardoso, Jorge C. S.; Figueiredo, Humberto; Correia, Virgílio Hipólito Abstract: Digital tools have the potential to help document and disseminate knowledge about, and engage people with cultural heritage artifacts. They can also help bridge the gap between physical and virtual heritage facilitating the comprehension of the context of usage while at the same time opening up the possibilities inherent to digital visualization. In the context of Creatour's pilot project "Mosaic-Conímbriga and Sicó" we are creating the foundations for the integration of digital tools in the exploration of the vast Roman mosaic patrimony in the Sicó region. Specifically, we are developing software applications that will contribute to - enhancing visits to mosaic sites by taking advantage of Augmented Reality (AR) in mobile devices (e.g., to display digital information over the physical mosaics, extending the amount of information associated with mosaics), - increase awareness about roman mosaics in young audiences by developing computer tools for the creation of digital mosaics by different means (painter-like tools, computer programming tools, photograph "mosaicing" tools), - integration and re-interpretation of content by allowing the visualization of digitally created creative content in the context of physical roman mosaics (e.g., a virtual restoration of a mosaic created by children visualized through AR on top of the physical mosaic), - create a geographical database of mosaics in the region, raising awareness about less visited sites and providing in-situ and in-context information about specific Roman mosaics. In this presentation we will describe the various planned initiatives and present results regarding the first version of an AR application in the context of the Conímbriga site.

2018-01-01T00:00:00Z