Angélica de Antonio Jiménez

Comparative analysis of shape descriptors for 3D objects

One of the basic characteristics of an object is its shape. Several research areas in mathematics and computer science have taken an interest in object representation in both 2D images and 3D models, where shape descriptors are a powerful mechanism enabling the processes of classification, retrieval and comparison for object matching. In this paper, we present a literature survey of this broad field, including a comparative analysis based on the above shape descriptor processes. In view of their significance, we identified the shape descriptors implemented using the concept of visual salience. This paper gives an overview of this topic.One of the basic characteristics of an object is its shape. Several research areas in mathematics and computer science have taken an interest in object representation in both 2D images and 3D models, where shape descriptors are a powerful mechanism enabling the processes of classification, retrieval and comparison for object matching. In this paper, we present a literature survey of this broad field, including a comparative analysis based on the above shape descriptor processes. In view of their significance, we identified the shape descriptors implemented using the concept of visual salience. This paper gives an overview of this topic.

SCAFFOLDING TUTORING STRATEGY ON VIRTUAL ENVIRONMENTS FOR TRAINING

Because the conversational capabilities of pedagogical agents (embodiments of trainers) allow social interactions with learner(s), their application in 3D virtual environments for training, besides improving the interaction and giving more realism to virtual training, permits changes in tutoring strategies bringing closer the virtual experience to the real one. Scaffolding emerges from the work of some famous educators as an instructional paradigm and it is becoming more and more used in computer-based education. Of course, scaffolding application on virtual environments for trainings is very different from its original conception, and its application in a classroom. Virtual environments for training features, the pedagogical agent embodiment, and its possibilities of virtual interaction make possible the use of this strategy characterized by its adjustment to learner’s performance and its dynamic use of work tools, among others. This article explores the advantages of using scaffolding on virtual environments for training as a tutoring strategy for pedagogical agents, focusing on the key features of scaffolding and how they can be applied in pedagogical activities. Activity Theory as well as roles and reusable learning objects design by contract are used to model our proposal. Finally, one procedure to apply scaffolding as a tutoring strategy for pedagogical agents in virtual environment for training designed using the “Model for Application of Intelligent Virtual Environments to Formation” is proposed.

Hybridization of cognitive models using evolutionary strategies

Incorporating different kinds of micro-theories of cognition and modulating several mechanisms to unify all the recommended actions and outputs of an Intelligent System when a huge amount of environmental variables are changing continuously with increasing complexity, may become a very comprehensive task. The presented framework proposes an Hybrid Cognitive Architecture that relies on integrating of emergent systems approaches —connectionist and autopoietic systems—, and cognitivist approaches, in order to combine implicit and explicit processes necessary in developing cognitive skills. The proposed architecture includes different kinds of learning capabilities at each cognitive level which grant to the architecture a big plasticity. In addition, the propounded attention module includes an evolutionary mechanism based on gene expression programming to evolve a set of eligibility conditions in charge of modulating the coalition/ subordination of specialized behaviours, taking into consideration the theatre metaphor for consciousness. Finally, a co-evolutionary mechanism is proposed to propagate behaviours and knowledge between cognitive systems —Agents— on the basis of memetic engineering. The proposed architecture was proved in an animat environment using a multi-agent platform where several emergent properties of self-organization arose.

Collaborative Interaction Analysis in Virtual Environments Based on Verbal and Nonverbal Interaction

Similar to real life, in a Collaborative Virtual Environment the users’ interaction is accomplished not only by the verbal channel. The response to a request can be an action; also the users’ avatars body movements such as pointing or their gazes’ direction are helpful to send messages that may complement or even substitute verbal communication. In this paper we propose to extend the Sentence Opener approach, by which the intention of the verbal message is identified, with nonverbal communication analysis for a better collaborative interaction comprehension. This automatic analysis will provide an autonomous virtual tutor, with the tools to scaffold interaction during a training situation, for a task of socio-technical nature in a Collaborative Virtual Environment.

Modulation of multi-level evolutionary strategies for artificial cognition

Integrating different kinds of micro-theories of cognition in intelligent systems when a huge amount of variables are changing continuously, with increasing complexity, is a very exhaustive and complicated task. Our approach proposes a hybrid cognitive architecture that relies on the integration of emergent and cognitivist approaches using evolutionary strategies, in order to combine implicit and explicit knowledge representations necessary to develop cognitive skills. The proposed architecture includes a cognitive level controlled by autopoietic machines and artificial immune systems based on genetic algorithms, giving it a significant degree of plasticity. Furthermore, we propose an attention module which includes an evolutionary programming mechanism in charge of orchestrating the hierarchical relations among specialized behaviors, taking into consideration the global workspace theory for consciousness. Additionally, a coevolutionary mechanism is proposed to propagate knowledge among cognitive agents on the basis of memetic engineering. As a result, several properties of self-organization and adaptability emerged when the proposed architecture was tested in an animat environment, using a multi-agent platform.

SCORM Compliant-Architecture for Including Simulations in E-learning Systems

The integration of interaction and simulation in e-learning systems represents a milestone in educational research and supports the student’s learning process in innumerable ways. Nevertheless, current standards do not provide appropriate mechanisms to treat simulations as learning objects, which makes their integration into e-learning systems a hard task. This work proposes an architecture as extension to SCORM which includes a Tutoring Module for Simulations (TMS). The main objective consists in providing mechanisms to track and “observe” the student’s actions while interacting with a simulation, thus enabling the TMS to take decisions or intervene when necessary, and/or to modify the simulation course.