Edgard Benítez-Guerrero

Context-Aware Mobile Collaborative Systems: Conceptual Modeling and Case Study

A Mobile Collaborative System (MCOS) enable the cooperation of the members of a team to achieve a common goal by using a combination of mobile and fixed technologies. MCOS can be enhanced if the context of the group of users is considered in the execution of activities. This paper proposes a novel model for Context-Aware Mobile COllaborative Systems (CAMCOS) and a functional architecture based on that model. In order to validate both the model and the architecture, a prototype system in the tourism domain was implemented and evaluated.

A Model and Language for Bitemporal Schema Versioning in Data Warehouses

A data warehouse (DW) is a vast collection of historical data built to support multidimensional data analysis applications. In this context, an important problem is that of evolving the implementation (multidimensional, relational) schema of a DW to incorporate new requirements. This paper introduces a conceptual evolution model based on bitemporal versioning of multidimensional schemas, which allows one to modify the DW schema (a) in an implementation-independent manner, and (b) without affecting the operation of existing applications. It also presents a SQL-like language associated to this model, which offers expressions to create and change versions of multidimensional schemas

Reasoning on expressive description logics with arithmetic constraints

Description logics (DL) is a well-known knowledge representation formalism. DL have been applied as reasoning framework in diverse domains, including the Semantic Web and Context-Aware Systems. It is an open question whether or not the expressive description logic ALCQIOreg is decidable. This logic is equipped with negation, conjunction, regular roles, inverse roles, nominals and qualified number restrictions. In this paper, we show this logic is decidable when interpreted over tree models. Moreover, it is shown that μALCTIO, which is known to be undecidable and that subsumes ALCQIOreg, is in EXPTIME in the case of tree models. μALCTIO generalizes regular roles with fixed-point constructors, and qualified number restrictions with arithmetic constraints. This EXPTIME bound holds even if the arithmetic constraints are coded in binary. Furthermore, we show that knowledge base reasoning, TBoxes and ABoxes, can also be decided in EXPTIME. These results are achieved via a polynomial reduction to the satisfiability problem of the propositional modal ¡-calculus extended with Presburger arithmetic constraints interpreted over tree models.

On the Model Checking of the Graded \(\mu \)-calculus on Trees

The \(\mu \)-calculus is an expressive propositional modal logic augmented with least and greatest fixed-points, and encompasses many temporal, program, dynamic and description logics. The model checking problem for the \(\mu \)-calculus is known to be in NP \(\cap \) Co-NP. In this paper, we study the model checking problem for the \(\mu \)-calculus extended with graded modalities. These constructors allow to express numerical constraints on the occurrence of accessible nodes (worlds) satisfying a certain formula. It is known that the model checking problem for the graded \(\mu \)-calculus with finite models is in EXPTIME. In the current work, we introduce a linear-time model checking algorithm for the graded \(\mu \)-calculus when models are finite unranked trees.

Towards a Context-Aware Framework for Improving Collaboration of Users in Groupware Systems

A Context-Aware Groupware System (CAGS) enables the members of a team to communicate, cooperate and coordinate their activities to achieve a common goal, by providing them tools that are aware of their current execution context and adapt accordingly. CAGS can be found in several domains such as entertainment, particularly Collaborative First-Person-Shooter (FPS) video games. In CAGS, the means of collaboration traditionally provided to users (e.g. text and audio messaging) are not necessarily adequate: for instance, in a FPS, messages can distract the gamer due to the speed of the game. This paper reports a study that, for Collaborative FPS, identifies advantages/disadvantages of current means of collaboration and social behaviors that arise when players interact face-to-face or remotely. Based on this study, a context-aware conceptual model and architecture is proposed for CAGS aimed to improve user collaboration.

Context-Aware Groupware Systems and Video Games: State of the Art

A Context-Aware Groupware System (CAGS) is software that enables the members of a team to communicate, cooperate and coordinate their activities in order to achieve a common goal, by providing them tools which are aware of their current execution context and adapt accordingly. CAGS are present in multiple domains (e.g. health, tourism), and particularly, in entertainment, collaborative videogames are a current topic of interest. This paper surveys the state of the art of CAGS, and particularly of Context-Aware Collaborative Video Games, in order to identify individual and social context information to be used by the next generation of collaborative systems.

A Tangible System for Learning Relational Algebra

Tangible User Interfaces (TUIs) are those in which users interact with a digital system through the direct manipulation of physical objects (tokens). Tokens are directly linked to a certain data/functionality within the system, so manipulation of these objects affects the system behavior. This paper introduces TanQuery, a tangible system to support the process of learning Relational Algebra. TanQuery incorporates components to detect and track tokens, and to analyze and execute query trees. The system was tested by university students, and obtained results allowed to observe and analyze that students found this type of interface useful and pleasant. Keywords: Tangible user interfaces; relational algebra.

Towards an intelligent desk matching behaviors and performance of learners

This paper proposes the design of a system to semi-automatically identify possible relationships between learner behavior and task performance in an intelligent desk. The aim of detecting such relationships is to help teachers and students in the learning process, supporting their activities with an unobtrusive observation to identify special needs to improve their performance. The proposed system is based on models of the desk, of behaviors arising from user-object interactions, and task performance. Its components are designed to address four main functions: data acquisition, behavior identification, task performance identification, and computing relationships between behaviors and task performance.

TanQuery: a tangible system for relational algebra learning

This paper introduces TanQuery, a tangible system prototype aimed to support the learning process of relational algebra (RA). In this system, RA operators and operands are represented by tokens that can be manipulated by the user to interactively create query trees. The design of TanQuery incorporates components to detect and track tokens, and to analyze and execute query trees. A working prototype has been developed and tested for usability. The results of prototype test, allow to observe that students found this type of interface pleasant, however, we need to make general improvements to prototype and realize further user studies.

Applying usability evaluation methods with blind users: a systematic mapping study

The main objective of this work is to perform a systematic mapping of the literature to know if the works that have been done and that are focused on the blind users make use of usability evaluation methods. For this we perform a review of different databases to obtain works focused on the topic. As a result, it is observed that the related work makes little use of usability evaluation methods, however, they make it clear why it is important to evaluate the projects taking into account users with visual disability.