Papers
Fuzzy Information Retrieval Model Based on Multiple Related Ontologies
Co-authored with Angelica Leite. Published in EADCA'2009
With the World Wide Web popularity the information retrieval area has a new challenge intending to retrieve information resources by their meaning by using a knowledge base. Nowadays ontologies are being used to model knowledge bases. To deal with knowledge subjectivity and uncertainty fuzzy set theory techniques are employed. Preceding works encode a knowledge base using just one ontology. But a document collection can deal
with different domain themes, expressed by distinct ontologies. In this work a way of knowledge organization and representation as multiple related ontologies was investigated and a method of query expansion was developed. The knowledge organization and the query expansion method were integrated in the fuzzy model for information retrieval based on mutiple related ontologies. The model performance was compared with another fuzzy-based approach for information retrieval and with the Apache Lucene search engine. In both cases the proposed model improves the
precision and recall measures.
Designing digital annotation with metaphor entailments
Co-authored with Christian Adriano, Matthias Brust, and Steffen Rothkugel. Published in ICETE'2008
We investigate educational technology design by means of porting metaphors from different usage scenarios. Even though such approach is common for usability engineering, it is novel to domain-driven design. The metaphor adopted is the annotation on documents. We surveyed metaphors in current digital annotation systems and analyzed metaphorical implications (defined as entailments). It was possible to extract essential and accidental features. We probed the rationale by porting metaphors to an educational software engineering scenario supported by Eclipse IDE. We concluded that entailments should play a role as domain-driven pattern. Questions for further research are offered.
Using Multiple Related Ontologies in a Fuzzy Information Retrieval Model
Co-authored with Angelica Leite. Published in WONTO'2008.
With the Semantic Web progress many independently developed distinct domain ontologies have to be shared and reused by a variety of applications. The use of ontologies in information retrieval applications allows the retrieval of semantically related documents to an initial users’ query. This work presents a fuzzy information retrieval model for improving the document retrieval process considering a knowledge base composed of multiple domain ontologies that are fuzzy related. Each ontology can be represented independently as well as their relationships. This knowledge organization is used in a novel method to expand the user initial query and to index the documents in the collection. Experimental results show that the proposed model presents better overall performance when compared with another fuzzy-based approach for information retrieval.
Cooperative, Geographically Distributed Development of Open Educational Modules
Co-authored with Ellen Barbosa, Elisa Nakagawa, Fabio Kon, Marcelo Turine, Débora Paiva. Published in CHARLA'2008.
Several initiatives on using computing technologies have been investigated in order to facilitate the learning process
in general. The idea is to provide ways to establish quality educational products, capable of motivating the students and
effectively contribute to their knowledge construction processes in active learning environments.
Redesigning Computer-Based Learning Environments: Evaluation as Communication
Co-authored with Matthias Brust and Christian Adriano. Published in ICEIS'2007.
In the field of evaluation research, computer scientists live constantly upon dilemmas and conflicting theories. As evaluation is differently perceived and modeled among educational areas, it is not difficult to become trapped in dilemmas, which reflects an epistemological weakness. Additionally, designing and developing a computer-based learning scenario is not an easy task. Advancing further, with end-users probing the system in realistic settings, is even harder. Computer science research in evaluation faces an immense challenge, having to cope with contributions from several conflicting and controversial research fields. We believe that deep changes must be made in our field if we are to advance beyond the CBT (computer-based training) learning model and to build an adequate epistemology for this challenge. The first task is to relocate our field by building upon recent results from philosophy, psychology, social sciences, and engineering. In this article we locate evaluation in respect to communication studies. Evaluation presupposes a definition of goals to be reached, and we suggest that it is, by many means, a silent communication between teacher and student, peers, and institutional entities. If we accept that evaluation can be viewed as set of invisible rules known by nobody, but somehow understood by everybody, we should add anthropological inquiries to our research toolkit. The paper is organized around some elements of the social communication and how they convey new insights to evaluation research for computer and related scientists. We found some technical limitations and offer discussions on how we relate to technology at same time we establish expectancies and perceive others work.
The TIDIA-Ae Portfolio Tool: a case study of its development following a component-based layered architecture
Co-authored with Delano Beder and others. Published in TIDIA Workshop, 2005.
The objective of the present case study is the validation of the Architecture and Development Process definitions used within the TIDIA-Ae Project, as exemplified in the development of the Portfolio tool. In this way, the main results obtained in the
development process of the Portfolio tool, the solutions adopted for the open issues encountered in this process, and the main lessons to be learned are presented.
A Reference Software Model for Intelligent Information Search
Co-authored with Fernando Gomide. Book chapter: Enhancing the power of Internet, 2004
This chapter provides a tutorial review of the current state of the art in the area of Web search and addresses information retrieval models that induce a reference software model for intelligent search systems. For these purposes, we review current information Web search models and methods from the point of view of information retrieval systems. Next, we present a reference software model which abstracts the search and retrieval process. This abstraction is important to identify the points of adaptation to integrate soft computing techniques into the information search and retrieval. We discuss the contributions that machine learning, artificial and computational intelligence brought to improve information retrieval models to enhance information search effectiveness, and to develop intelligent information search. The purpose of the model is to capture the relationships between computational intelligence and information search systems as a means to promote development and implementation of innovative, intelligent information search systems.
Activity Coordination in Collaborative Learning Environments
Co-authored with Carlos José Olguin and Alberto Raposo. Published in CSAC'2004.
In the context of computer-supported collaborative learning, discussions are essential to increase the knowledge level of the members of a group. This work proposes the modeling of the discussion activities of a study group using an activities coordination model. Starting from the formal modeling of the system, and using coordination mechanisms based on Petri Nets, the behavior of the environment can be simulated and analyzed. These simulations allow anticipating possible problems and help to turn interactions among students more efficient.
Exploring Learning Objects under Conceptual, Instructional and Didactic Perspectives
Co-authored with Ellen Barbosa and José Carlos Maldonado. Published in PGL Database Research, 2003.
The idea of Learning Objects – “any digital resource that can be reused to support learning” – is emerging as a way to reuse learning materials in different settings and contexts. Standardization efforts have also been conducted, especially related to the establishment of learning object metadata, describing the relevant characteristics that a learning object should present. This work aims at exploring learning objects according to the conceptual, instructional and didactic perspectives, which have been investigated in the context of domain modeling for the development of learning materials. Our goal is to investigate the impact of these perspectives into the set of characteristics specified by the standards for Learning Objects Metadata under development.
Extending adaptation frontiers for learning sets
Co-authored with Carlos Tobar. Published in FIE'2003.
Several models and frameworks have been proposed for adaptive hypermedia systems, but when it comes to the integration with application models these proposals lack expressiveness, blurring combinations of functional components or information categories, sometimes with abstractions layers. This is very clear for educational applications, where matters such as collaboration and cognitive styles are not cleanly integrated to hypermedia modeling issues. The Extended Abstract Categorization Map is being proposed as a comprehensive framework, considering educational applications, where complementary modeling perspectives are adequately separated but still integrated. The resulting separation of concerns yields a clearer understanding of how adaptation issues can be affected by educational goals.
Devising Adaptive Migration Policies for Cooperative Distributed Genetic Algorithms
Co-authored with Edgar Noda, André Coelho, and others. Published in IEEE MSC'2002.
Distributed Genetic Algorithms (DGAs) constitute an interesting approach to undertake the premature convergence problem in evolutionary optimization. This is done by spatial partitioning a huge panmitic population into several semi-isolated groups, called demes, each evolving in parallel by its own pace, and possibly exploring different regions of the search space. At the center of such approach lies the migratory process that simulates the swapping of individuals belonging to different demes, in such a way to ensure the sharing of good genetic material. In this paper, we model the migration step in DGAs as an explicit means to promote cooperation among genetic agents, autonomous entities encapsulating GA instances for possibly tackling different sub-problems of a complicated task. The focus is on the characterization of adaptive migration policies in which the choice of what individuals to migrate and/or replace is not defined a priori but according to a more knowledge-oriented rule. Comparative results obtained for a data-mining task were conducted, in order to assess the performance of adaptive migration according to efficiency/effectiveness criteria.
Tasks interdependencies in collaborative learning activities: Specification and modeling
Co-authored with Alberto Raposo. Published in CATE'2002.
In collaborative environments, coordination is an essential matter to the specification of activities, which are described as sets of interdependent tasks. An extensible framework encompassing coordination mechanisms to specify tasks interdependencies is initially presented. These mechanisms are formally modeled using Petri nets and, along with a Petri net representation for the tasks to be performed, can be used to create a model to evaluate the environment. The use of this framework is illustrated in the context of a learning environment based on collaborative Web document construction.
Coordination of Collaborative Activities: A Framework for the Definition of Tasks Interdependencies
Co-authored with Alberto Raposo, Léo Magalhães and Hugo Fuks. Published in the Seventh International Workshop on Groupware, 2001
The coordination of interdependencies between tasks in collaborative environments is a very important and difficult endeavor. The separation between tasks and interdependencies allows for the use of different coordination policies in the same collaborative environment by changing only the coordination mechanisms that control the interdependencies. This paper presents a framework for the definition of interdependencies that frequently occur in collaborative activities. By means of a clear characterization of interdependencies, it is possible to identify coordination mechanisms to manage them, opening the way toward a powerful coordination tool capable of encompassing a wide range of collaborative applications. An implementation of the coordination model of a collaborative virtual environment based on the proposed framework is given as example.
Using Fuzzy Petri Nets to Coordinate Collaborative Activities
Co-authored with Alberto Raposo, André Coelho, and Léo Magalhães. Published in IFSA/NAFIPS World Congress, 2001.
This paper presents a fuzzy Petri net based approach suitable for the modeling of flexible coordination mechanisms to deal with temporal interdependencies between collaborative tasks. Such approach is based on an extension of the Generalized Fuzzy Petri Net model, including the notion of time for the execution and synchronization of these tasks. A scenario of study is described, indicating the suitability of the proposal.
Bringing Flexibility to the Specification and Coordination of Temporal Dependencies among Multimedia Components
Co-authored with André Coelho and Alberto Raposo. Published in SBMIDIA'2001.
We introduce a methodology for the high-level specification and decentralized coordination of temporal interdependencies among multimedia document objects. Such methodology encompasses a three-step process comprising (i) the design of multimedia presentation scenes by means of a fuzzy descriptive plan; (ii) the parsing of such layout to classify the multimedia entities that compose the scenes and to check the consistency of temporal relationships among them; and (iii) the generation of event-driven time and action managers as distributed mechanisms for the orchestration of the elements presentation. This approach centers around a novel multimedia synchronization model based on fuzzy sets and software components concepts.
Emergence of multiagent spatial coordination strategies through artificial coevolution
Co-authored with André Coelho, Daniel Weingaertner and Ricardo Gudwin. Published in Computer and Graphics, 2001.
This paper describes research investigating the evolution of coordination strategies in robot soccer teams. Each player (viewed as an agent) is provided with a common set of skills and is assigned to perform over a delimited area inside a soccer field. The idea is to optimize the whole team behavior by means of a spatial coadaptation process in which new players are selected in such a way to comply with the already existing ones. The main results show that, through coevolution, we progressively create teams whose members act on complementary areas of the playing field, being capable of prevailing over a standard opponent team with a fixed formation.
Petri nets based coordination mechanisms for multi-workflow environments
Co-authored with Alberto Raposo and Léo Magalhães. Published in the International Journal of Computer Systems Science and Engineering, 2000
The coordination of cooperative workflows occurs in parallel to the definition of a common communications infrastructure among organizations. In this paper, we present a library of coordination mechanisms modeled with Petri Nets. These mechanisms specify and control the interaction between workflow processes. The separation between activities and dependencies, managed by the coordination mechanisms, allows the reuse of these mechanisms in other environments and also the use of different coordination policies in the same environment.
An Agent Infrastructure to Set Collaborative Environments
Co-authored with Armando Delgado and Carlos José Olguin. Published in Educational Technology and Society, 2000.
Collaborative learning supported through computers seems to be very promising, since advances in computational technology enable the widespread use of tools such as bulletin boards, chats, whiteboards and even video-conference. However, it is not clear which approach for on-line learning individual or collaborative is more effective for the students. This paper addresses a proposal to combine both approaches, taking in account that some advantages related to individual learning, such as self-pacing and
establishment of learning goals by the learner, imply in difficulties to establish collaborative settings. This proposal is based upon the dynamic creation and management of study groups of distributed learners sharing on-line material. A model is proposed to set collaboration profiles that would enable to identify potential collaborators, and an agent-based infrastructure is presented to support this model in an on-line learning environment. Finally, an example of use of this infrastructure is presented using CALM, a learning environment developed on top of the Web architecture.
Changing Interaction Paradigms in Annotation Environments
Co-authored with Christian Adriano, Alberto Raposo, and Léo Magalhães. Published in EDMEDIA'2000.
Implementation of novel learning scenarios frequently implies the adoption of new interaction paradigms provided by new media. Changes on media bring several issues to educational metaphors, such as deciding which characteristics should be maintained, removed and improved. This paper discusses these issues by means of a case study comparing evolving scenarios for the annotation metaphor: from paper-based to hypertext and virtual reality.
Coordinating Activities in Collaborative Environments: A High Level Petri Nets Based Approach
Co-authored with Alberto Raposo and Léo Magalhães. Published in SCI'2000.
The coordination of interdependencies among activities in collaborative environments is a very important and difficult task. In this paper we present a set of coordination mechanisms for the specification and control of interaction among collaborative activities. To model these mechanisms, we use high level Petri nets, which have proven to be an adequate approach to evaluate the behavior of a computer supported collaborative system before its implementation.
Fostering Theoretical, Empirical and Tool Specific Knowledge in a Software Testing Learning Scenario
Co-authored with Ellen Barbosa, Christian Adriano, José Carlos Maldonado, and Mario Jino. Published in ICECE'2000.
Teaching some subjects, as for example Computer Science, concerns the support for a learning process that involves cooperation of theoretical and empirical knowledge with related software tools. The underlying hypothesis is that there is a lack of appropriate support, to students and instructors, to the apprenticeship of specific theories and skills. The current research aims at a more specific learning scenario – Software Testing – addressing of what would be these specific theories and skills. A Software Testing Lab requires three cooperating types of knowledge – theoretical, empirical and tool specific, which together compose the learning and the evaluation process. To investigate such hypothesis, a specific learning scenario is implemented within a platform named CALM. This learning
scenario comprises a unit testing activity and the support of an integrated testing tool – PokeTool. With the implemented learning scenario we hope to be in a position to suggest more specific guidelines to be integrated into the platform CALM. It is expected that this experience can also be extended to other software engineering courses.
Coordination Mechanisms for Collaborative Virtual Environments
Co-authored with Alberto Raposo and Léo Magalhães. Published in WRV'2000.
In order to be effectively used as collaborative work tools, developers of virtual environments should invest, among other aspects, in the coordination of users’ activities. The goal of this work is to present coordination mechanisms that may be reused in different implementations of collaborative virtual environments (CVEs).
A collaboration framework for on-line learning environments
Co-authored with Carlos José Olguin and Armando Delgado. Published in RIBIE'2000.
Collaborative learning supported through computers seems to be very promising, since advances in computational technology enable the widespread use of tools such as bulletin boards, chats, whiteboards and even video-conference. However, it is not clear which approach for on-line learning – individual or collaborative – is more effective for the students. This paper addresses a proposal to combine both approaches, taking in account that some advantages related to individual learning, such as self-pacing and establishment of learning goals by the learner, imply in difficulties to establish collaborative settings. This proposal is based upon the dynamic creation and management of study groups of distributed learners sharing on-line material. A model is proposed to set collaboration profiles that would enable to identify potential collaborators, and an agent-based infrastructure is presented to support this model in an on-line learning environment. Finally, an example of use of this infrastructure is presented using CALM, a learning environment developed on top of the Web architecture.
Distributed multimedia persistence support for educational activities
Co-authored with André Coelho. Published in SCI'2000.
Under most of the new technological-focusing learning approaches, one of the primal objectives is that of the incremental design and construction of an instructional environment more centered upon the learners’ particular necessities and profiles. In such respect, multimedia tools and services have already been proposed and customized as the underpinnings to a broader range of more adequate educational and training software applications. In order to augment and extend this support over larger domains, there is now such a tendency to integrate these mechanisms with those obtained within the Distributed Systems arena. In this paper, a distributed multimedia persistence layer, which enables the seamless integration of multimedia databases with media dedicated storage servers, is evaluated as such an underlying service bringing support to customary educational activities. With this purpose, some computational requirements commonly associated with the handling of learning materials are first presented, assessing their impact on the assisting middleware systems. Finally, three scenarios of study are investigated emphasizing the new service functionalities.
Inquiring the Course Paradigm with CALM
Co-authored with Christian Adriano, Armando Delgado, Luiz Silveira, Raquel Bosnardo, and Léo Magalhães. Published in ICECE'1999.
The configuration of theoretical courses complemented by "hands on" laboratories has been shown effective to internalize theory, give concrete context and enhance skills. However, learning the "hands on" tools dispenses usually unaffordable time; that is particularly true for computer programming, since the amount of programming language taught during theory does not suffice to the lab practice. To lessen such problem by supporting extra-course apprenticeship, a collaborative learning system was discussed and developed. CALM–Computer Aided Learning Material is the resulting proposal with an underlying philosophy of complementing the traditional course paradigm with a goal directed learning strategy.
Towards a categorization of hypermedia data models
Co-authored with Carlos Tobar. Published in MMM'1999.
Several hypermedia data models have been proposed in order to face hypermedia as a paradigm to develop information-oriented systems. However, hypermedia modeling introduces very specific requirements not found within conventional database modeling due to several issues must be considered during a design effort, such as modeling of data navigation, data perception, and human-machine interaction. Most of present data models oriented to hypermedia present differences on abstraction level, modeling issues, and considered data aspects. An Abstract Categorization Map is proposed as a graphical tool through which it is possible to assess and compare existing specification mechanisms of data models oriented to hypermedia. The map allows an analysis of existing models as an exercise to relate them and therefore derive strengths, weaknesses, overlaps, or omissions. It also allows observing existing gaps between the modeling of data considering different levels of abstraction.
Animation modeling with Petri Nets
Co-authoring with Alberto Raposo and Léo Magalhães. Published in Computer and Graphics, 1998
This paper introduces the use of Petri Nets as a modeling and analysis tool for animation environments. First of all the original formulation for Petri Nets is applied in two animation situations. The first one is modeled as a state machine and the second one explores interdependent transitions. Increasing the complexity level, some modeling extensions are discussed and a more sophisticated animation example is presented.
A Framework for Assessing and Comparing Multimedia and Hypermedia Authoring Methodologies
Co-authored with Carlos Tobar. Published in MSE'1998.
The importance of data perception by the user has demanded data models oriented to individuals, whose emphasis is information description at high levels of abstraction. Altogether new data modeling requirements have arisen, mainly because of information technology improvements such as multimedia and hypermedia incorporation to documents. These and others considerations have produced new brands of evolving data models. Model-based approaches to hypermedia design are authoring methodologies that make use of some of the newest data models in order to begin from high level abstractions a step-by-step process directed to low level specifications trying to cope with multimedia and hypermedia in a user oriented fashion. A development approach ofmultimedia and hypermedia oriented datamodels is proposed, named hook approach, that basically establishes the need for facilitator mechanisms to allow mappings between data models of different abstraction levels. In order to point out the broadness of authoring methodologies and even to allow their comparison an Abstract CategorizationMap is also proposed. This map can be used to present data model adherence to the hook approach and also can be used as a reference framework for the development of data models oriented to support multimedia and hypermedia information applications.
Working with Remote VRML Scenes through Low-Bandwidth Connections
Co-authored with Alberto Raposo and Léo Magalhães. Published in SIBGRAPI 1997.
We have developed a Web-based application to accelerate the visualization of VRML scenes located in a remote server. This application enables the user to extract only the parts of a scene that are of actual interest. The extracted parts represent one or more sub-trees of the hierarchical structure of the VRML scene, and only these parts will be rendered and visualized in the local computer. By reducing the complexity (size) of the remote scene, less data are transmitted from the remote server and the rendering process becomes faster in the local computer. The application is written in Java and is executed as an applet embedded in an HTML page.
Building Interactive Animations using VRML and Java
Co-authored with Fabiana Tamiosso, Alberto Raposo, and Léo Magalhães. Published in SIBGRAPI, 1997
This paper exploits the combination of VRML (Virtual Reality Modeling Language) and Java for the construction of highly interactive animations, whose behavior is defined in real-time by user’s actions. The animations are modeled in VRML, which allows the definition of a Java program to process and generate events that determine the behavior of scene elements. An application for the generation of Java graphical interfaces was developed, aiming to establish the communication between the user and the VRML environment, sending parameters to the program that controls the animation.
Towards an architecture for distributed multimedia databases
Co-authored with Carlos Tobar. Published in ICIIS'1996.
The widespread use of multimedia resources has been demanding the reengineering of a broad class of supporting software in order to ease the implementation of multimedia applications. In this paper, we address the features a database system should provide in order to support multimedia applications, with emphasis on its integration to distributed platforms. The architecture of a prototype multimedia database, the Multiware Database, is presented.
Muliware database: A distributed object database system for multimedia support
Co-authored with Carlos Tobar. Published in ICODP'1995.
This paper describes the Multiware Database, a database capable to store and manage complex multimedia documents using the features of both object management systems and open distributed systems.
Analysis of pipelined external sorting on a reconfigurable message-passing multicomputer
Co-authored with Bernard Menezes and Ramki Thurimella. Published in Parallel Computing, 1993.
External sorting is a frequent operation in relational database systems, sometimes as a step in important operations such as joins. Therefore, external sorting on a parallel system is a key index of system performance for database applications. However, the problem of external sorting on multicomputers is not as well understood as parallel internal sorting, when keys reside in main memory. In many case, analysis is performed under assumptions such as unlimited resources (number of processors, amount of memory, network bandwidth) and full overlapped use of resources, limiting its applicability in practice. [...]
External sorting on a reconfigurable message-passing multicomputer: Experimental results and analysis
Co-authored with Bernard Menezes and Ramki Thurimella. Published in MWSCS'1992
In this paper, we report on an actual implememtation of the external sorting problem on a multicomputer with careful attention paid to the overlap bewteen computation and I/O in order to minimize total execution time. The problem is divided into two steps - the first involves creation of multiple sorted runs (Step 1), the second involves merging the runs (Step 2). Step 1 was accomplished using pipelined sort; Step 2 was implemented on a tree of processors. We also present an analytical model for Step 1; the execution time predicted by the proposed analytical model is compared with the experimental results.
MOODS: A Modular, Object-Oriented Design Database System
Published in CAPE'1989
MOODS is a database management system that can control multiple physical databases integrated through the object oriented paradigm. In addition to enabling the representation of design data, this system can represent data associated to the
design process and to integrate designers’ supporting tools in a uniform way. Hence, MOODS can support a multimedia database, with adequate features not only for engineering design but also for a broader class of non-conventional applications.
Supporting design environments through the entity-relationship model
Co-authored with Armando Delgado and Léo Magalhães. Published in WCSC'1988.
Design environments are characterized by two kinds of processes, one related with design control and other with the design itself. This article presents an extension of the entity-relationship model which on one hand supports both processes - defining the called micro and macro aspects, and on the other hand offers a semantical modelling tool based on rules.
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