CRACS - Indexed Articles in Conferences

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    An External Database for Prolog
    ( 1989) José Paulo Leal ; 5125
    This work describes a disk-resident database for Prolog which uses mechanisms similar to the ones used by the clausal database for recording and retrieving terms. It is intended to be used by applications requiring a flexibility greater than that provided by an interface to traditional database system. There is almost no restriction on the terms stored in the database and the retrieval mechanisms produces terms in the order they were recorded. To enhance the performance of the system, the database organization provides an access mechanism using hash-codes on ”key” arguments of the recorded term. The database also provides basic support for multi-user access. © Springer-Verlag Berlin Heidelberg 1989.
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    An External Database for Prolog
    ( 1989) José Paulo Leal ; 5125
    This work describes a disk-resident database for Prolog which uses mechanisms similar to the ones used by the clausal database for recording and retrieving terms. It is intended to be used by applications requiring a flexibility greater than that provided by an interface to traditional database system. There is almost no restriction on the terms stored in the database and the retrieval mechanisms produces terms in the order they were recorded. To enhance the performance of the system, the database organization provides an access mechanism using hash-codes on ”key” arguments of the recorded term. The database also provides basic support for multi-user access. © Springer-Verlag Berlin Heidelberg 1989.
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    Rapid development of web interfaces to heterogeneous systems
    ( 2007) José Paulo Leal ; 5125
    The general problem addressed in this paper is the rapid development of web interfaces to software systems using only their command line interface. This kind of system is frequently developed in environments that greatly differ from those where web interface will be implemented. In this setting it is also important to maintain a loose coupling between the web interface and the system it controls since the latter must be able to continue its normal development independently of the former. We propose a framework to develop web interfaces targeted to these systems whose main feature is the fact that it can be extended without requiring code programming. The hot spots of our framework are XML configuration files to define the interface data, how this data is mapped into the system's commands, and how commands output and the interaction state is mapped into web formatting languages. With this approach the web interface is kept separated from the system it controls, it is easy to define and modify, and is able to capture enough domain knowledge to be a real advantage for the novice or sporadic user. In this paper we present the proposed framework architecture, loosely inspired in the MVC pattern, its implementation on Java servlet containers, and its application to the AGILMAT system, a high-school mathematical problem generator developed using constrained grammars.
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    Integration of e-Learning Systems With Repositories of Learning Objects
    ( 2008) Ricardo Queirós ; José Paulo Leal ; 5695 ; 5125
    This paper describes a communication model to integrate repositories of programming problems with other e-Learning software components. The motivation for this work comes from the EduJudge project that aims to connect an existing repository of programming problems to learning management systems. When trying to use the existing repositories of learning objects we realized that they are mainly specialized search engines and lack features for integration with other e-Learning systems. With this model we intend to clarify the main features of a programming problem repository, in order to enable the design and development of software components that use it. The two main points of this model are the definition of programming problems as learning objects and the definition of the core functions exposed by the repository. In both cases, this model follows the existing specifications of the IMS standard and proposes extensions to deal with the special requirements of automatic evaluation and grading of programming exercises. In the definition of programming problems as learning objects we introduced a new schema for meta-data. This schema is used to represent meta-data related to automatic evaluation that cannot be conveniently represented using the standard: the type of automatic evaluation; the requirements of the evaluation engine; or the roles of different assets - tests cases, program solutions, etc. In the definition of the core functions we used two different web services flavours - SOAP and REST - and described each function as an operation for each type of interface. We describe also the data types of the arguments of each operation. These data types consist mainly on learning objects and their identifications, but include also usage reports and queries using XQuery.
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    A web application for mathematics education
    ( 2008) José Paulo Leal ; 5125
    AGILMAT is a web application designed to help students learn Mathematics, with focus on high-school algebra and calculus drills. A modular and extensible architecture and a wizard-based configuration interface decoupled from the system core are major design features of AGILMAT. The drill expressions are specified by grammars and constraints imposed by default profiles and user options, so that AGILMAT may support distinct learning levels and stages. The core system uses symbolic manipulation and automated reasoning to provide correct answers for the drills. The paper shows how AGILMAT may be used to create and customize drills automatically.
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    Designing a user interface for repositories of learning objects
    ( 2009) José Paulo Leal ; Ricardo Queirós ; 5125 ; 5695
    This paper presents the design of a user interface for repositories of learning objects. It integrates several tasks, such as submission, browse, search, and comment/review of learning objects, on a single screen layout. This design is being implemented on the web front-end of crimsonHex, a repository of specialized learning objects, developed as part of the EduJudge, a European project that aims to bring automatic evaluation of programming problems to e-Learning systems. © 2009 IADIS.
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    CrimsonHex: A Service Oriented Repository of Specialised Learning Objects
    ( 2009) Ricardo Queirós ; José Paulo Leal ; 5695 ; 5125
    The corner stone of the interoperability of eLearning systems is the standard definition of learning objects. Nevertheless, for some domains this standard is insufficient to fully describe all the assets, especially when they are used as input for other eLearning services. On the other hand, a standard definition of learning objects in not enough to ensure interoperability among eLearning systems; they must also use a standard API to exchange learning objects. This paper presents the design and implementation of a service oriented repository of learning objects called crimsonHex. This repository is fully compliant with the existing interoperability standards and supports new definitions of learning objects for specialized domains. We illustrate this feature with the definition of programming problems as learning objects and its validation by the repository. This repository is also prepared to store usage data on learning objects to tailor the presentation order and adapt it to learner profiles.
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    Responding to questionnaires on the Web using XwQuest
    ( 2009) José Paulo Leal ; 5125
    This paper reports on the design, implementation and evaluation of XwQuest, a Web tool for responding to questionnaires on the Web. The distinctive feature of this tool is an XML definition of the questionnaire that focus on questions and admissible answers while avoiding presentation details. This questionnaire definition is processed on the browser side and converted to an Ajax application. Collected responses are periodically sent back to the server and can be retrieved by researchers and processed on a standard spreadsheet program. The paper details the questionnaire language of XwQuest and a generator that converts them into Ajax applications. Two case studies where XwQuest was actually used with good results are also presented. © 2009 IADIS.
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    CrimsonHex: A Service Oriented Repository of Specialised Learning Objects
    ( 2009) Ricardo Queirós ; José Paulo Leal ; 5695 ; 5125
    The corner stone of the interoperability of eLearning systems is the standard definition of learning objects. Nevertheless, for some domains this standard is insufficient to fully describe all the assets, especially when they are used as input for other eLearning services. On the other hand, a standard definition of learning objects in not enough to ensure interoperability among eLearning systems; they must also use a standard API to exchange learning objects. This paper presents the design and implementation of a service oriented repository of learning objects called crimsonHex. This repository is fully compliant with the existing interoperability standards and supports new definitions of learning objects for specialized domains. We illustrate this feature with the definition of programming problems as learning objects and its validation by the repository. This repository is also prepared to store usage data on learning objects to tailor the presentation order and adapt it to learner profiles.
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    An architecture for the rapid development of XML-based web applications
    ( 2009) José Paulo Leal ; 5125
    Our research goal is the generation of working web applications from high level specifications. Based on our experience in using XML transformations for that purpose, we applied this approach to the rapid development of database management applications. The result is an architecture that defines of a web application as a set of XML transformations, and generates these transformations using second order transformations from a database schema. We used the Model-View-Controller architectural pattern to assign different roles to transformations, and defined a pipeline of transformations to process an HTTP request. The definition of these transformations is based on a correspondence between data-oriented XML Schema definitions and the Entity-Relationship model. Using this correspondence we were able produce transformations that implement database operations, forms interfaces generators and application controllers, as well as the second order transformations that produce all of them. This paper includes also a description of a RAD system following this architecture that allowed us to perform a critical evaluation of this proposal.
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    Mapping e-Learning Interactions using Social Network Analysis
    ( 2009) Álvaro Figueira
    The interactions that occur among participants in online forums frequently are an important criteria in evaluating learning methodologies practiced in e-learning contexts. Not only are the interactions between peers an important resource of information, but also, the way the teacher interacts with students. However, apart from general statistics available in common online learning platforms, this type of information is difficult to retrieve. A graphical mapping based on social network analysis theory, of such interactions that occur in online environments, is proposed as a possible solution for automatically depicting and analyzing relations that are established between participants in online forums. In this paper we present a system which provides learning management systems with an additional tool for graphically mapping and analyzing student-student and teacher-student interactions. The system represents both current network interactions and a historical graphical slideshow of online interactions between participants.
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    ELEARNING FRAMEWORKS: A SURVEY
    ( 2010) Ricardo Queirós ; José Paulo Leal ; 5695 ; 5125
    In recent years the concept of eLearning Framework emerged associated with several initiatives promoted by educational organizations. These initiatives share a common goal: to create flexible learning environments by integrating heterogeneous systems already available in many educational institutions. The paper provides an introductory survey on eLearning Frameworks. It gathers information on these initiatives categorizes them and compares their features regarding a set of predefined criteria such as: architecture, business model, primary user groups, technical implementations, adopted standards, maturity and future development.
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    Design of an extensible metadata editor based on RDF
    ( 2010) José Paulo Leal ; Ricardo Queirós ; 5125 ; 5695
    The content of a Learning Object is frequently characterized by metadata from several standards, such as LOM, SCORM and QTI. Specialized domains require new application profiles that further complicate the task of editing the metadata of learning object since their data models are not supported by existing authoring tools. To cope with this problem we designed a metadata editor supporting multiple metadata languages, each with its own data model. It is assumed that the supported languages have an XML binding and we use RDF to create a common metadata representation, independent from the syntax of each metadata languages. The combined data model supported by the editor is defined as an ontology. Thus, the process of extending the editor to support a new metadata language is twofold: firstly, the conversion from the XML binding of the metadata language to RDF and vice-versa; secondly, the extension of the ontology to cover the new metadata model. In this paper we describe the general architecture of the editor, we explain how a typical metadata language for learning objects is represented as an ontology, and how this formalization captures all the data required to generate the graphical user interface of the editor.
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    Specifying a Programming Exercises Evaluation Service on the e-Framework
    ( 2010) José Paulo Leal ; Ricardo Queirós ; 5125 ; 5695
    The e-Framework is arguably the most prominent e-learning framework currently in use. For this reason it was selected as basis for modelling a programming exercises evaluation service. The purpose of this type of evaluator is to mark and grade exercises in computer programming courses and in programming contests. By exposing its functions as services a programming exercise evaluator is able to participate in business processes integrating different system types, such as Programming Contest Management Systems, Learning Management Systems, Integrated Development Environments and Learning Object Repositories. This paper formalizes the approaches to be used in the implementation of a programming exercise evaluator as a service on the e-Framework.
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    Specifying a Programming Exercises Evaluation Service on the e-Framework
    ( 2010) José Paulo Leal ; Ricardo Queirós ; 5125 ; 5695
    The e-Framework is arguably the most prominent e-learning framework currently in use. For this reason it was selected as basis for modelling a programming exercises evaluation service. The purpose of this type of evaluator is to mark and grade exercises in computer programming courses and in programming contests. By exposing its functions as services a programming exercise evaluator is able to participate in business processes integrating different system types, such as Programming Contest Management Systems, Learning Management Systems, Integrated Development Environments and Learning Object Repositories. This paper formalizes the approaches to be used in the implementation of a programming exercise evaluator as a service on the e-Framework.
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    INTEGRATION OF REPOSITORIES IN ELEARNING SYSTEMS
    ( 2010) José Paulo Leal ; Ricardo Queirós ; 5125 ; 5695
    The wide acceptance of digital repositories today in the eLearning field raises several interoperability issues. In this paper we present the interoperability features of a service oriented repository of learning objects called crimsonHex. These features are compliant with the existing standards and we propose extensions to the IMS interoperability recommendation, adding new functions, formalizing message interchange and providing also a REST interface. To validate the proposed extensions and its implementation in crimsonHex we developed a repository plugin for Moodle 2.0 that is expected to be included in the next release of this popular learning management system.