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Publications

2014

Poster: Evaluation of Immersive Visualization Techniques for 3D Object Retrieval

Authors
Henriques, D; Mendes, D; Pascoal, P; Trancoso, I; Ferreira, A;

Publication
2014 IEEE SYMPOSIUM ON 3D USER INTERFACES (3DUI)

Abstract
The number and size of 3D object repositories have been increasing at a considerable rate. Consequently, finding a specific 3D model in such collections is getting more difficult. Current 3D search engines do not take advantage of novel interaction technologies, usually presenting query results in grids of thumbnails. This greatly hinders objects' interpretation and allows little to none manipulation at all. Immersive environments are believed as promising solutions for displaying 3D models, allowing complete representations of the models. These environments can be enhanced with multimodal techniques for a more natural interaction. In this paper we present a prototype that uses immersive visualization and mid-air interactions to explore query results in a dataset with 3D objects, using one of four different visualization modes. We evaluated these modes with 29 users and concluded that our immersive approaches are preferred by users and, albeit novel, perform at par relatively to traditional bi-dimensional grids with thumbnails.

2014

VOCE Corpus: Ecologically Collected Speech Annotated with Physiological and Psychological Stress Assessments

Authors
Aguiar, A; Kaiseler, M; Cunha, M; Silva, J; Meinedo, H; Almeida, PR;

Publication
LREC 2014 - NINTH INTERNATIONAL CONFERENCE ON LANGUAGE RESOURCES AND EVALUATION

Abstract
Public speaking is a widely requested professional skill, and at the same time an activity that causes one of the most common adult phobias (Miller and Stone, 2009). It is also known that the study of stress under laboratory conditions, as it is most commonly done, may provide only limited ecological validity (Wilhelm and Grossman, 2010). Previously, we introduced an inter-disciplinary methodology to enable collecting a large amount of recordings under consistent conditions (Aguiar et al., 2013). This paper introduces the VOCE corpus of speech annotated with stress indicators under naturalistic public speaking (PS) settings. The novelty of this corpus is that the recordings are carried out in objectively stressful PS situations, as recommended in (Zanstra and Johnston, 2011). The current database contains a total of 38 recordings, 13 of which contain full psychologic and physiologic annotation. We show that the collected recordings validate the assumptions of the methodology, namely that participants experience stress during the PS events. We describe the various metrics that can be used for physiologic and psychologic annotation, and we characterise the sample collected so far, providing evidence that demographics do not affect the relevant psychologic or physiologic annotation. The collection activities are on-going, and we expect to increase the number of complete recordings in the corpus to 30 by June 2014.

2014

3rd Symposium on Languages, Applications and Technologies, SLATE 2014, June 19-20, 2014 - Bragança, Portugal

Authors
Pereira, MJV; Leal, JP; Simões, A;

Publication
SLATE

Abstract

2014

Gearing Up and Accelerating Cross-fertilization between Academic and Industrial Robotics Research in Europe:

Authors
Röhrbein, F; Veiga, G; Natale, C;

Publication
Springer Tracts in Advanced Robotics

Abstract

2014

A Datalog Engine for GPUs

Authors
Martínez Angeles, CA; Dutra, I; Costa, VS; Buenabad Chávez, J;

Publication
DECLARATIVE PROGRAMMING AND KNOWLEDGE MANAGEMENT

Abstract
We present the design and evaluation of a Datalog engine for execution in Graphics Processing Units (GPUs). The engine evaluates recursive and non-recursive Datalog queries using a bottom-up approach based on typical relational operators. It includes a memory management scheme that automatically swaps data between memory in the host platform (a multicore) and memory in the GPU in order to reduce the number of memory transfers. To evaluate the performance of the engine, four Datalog queries were run on the engine and on a single CPU in the multicore host. One query runs up to 200 times faster on the (GPU) engine than on the CPU.

2014

A visual place recognition procedure with a Markov chain based filter

Authors
dos Santos, FN; Costa, P; Moreira, AP;

Publication
2014 IEEE INTERNATIONAL CONFERENCE ON AUTONOMOUS ROBOT SYSTEMS AND COMPETITIONS (ICARSC)

Abstract
Recognizing a place with a visual glance is the first capacity used by humans to understand where they are. Making this capacity available to robots will make it possible to increase the redundancy of the localization systems available in the robots, and improve semantic localization systems. However, to achieve this capacity it is necessary to build a robust visual place recognition procedure that could be used by an indoor robot. This paper presents an approach that from a single image estimates the robot location in the semantic space. This approach extracts from each camera image a global descriptor, which is the input of a Support Vector Machine classifier. In order to improve the classifier accuracy a Markov chain formalism was considered to constraint the probability flow according the place connections. This approach was tested using videos acquired from three robots in three different indoor scenarios - with and without the Markov chain filter. The use of Markov chain filter has shown a significantly improvement of the approach accuracy.

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