Publication: Automatización de los procesos para la generación, ensamblaje y reutilización de objetos de aprendizaje
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2005
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2005-07-13
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Abstract
En el trabajo presentado en esta memoria se identifican los problemas relacionados con la generación, ensamblaje y reutilización de objetos de aprendizaje. En particular, se ha identificado la carencia de modelos conceptuales
en el diseño y construcción de los actuales sistemas para la gestión de contenido de aprendizaje (LCMSs). Estos sistemas, aunque permiten en su mayoría, la integración y reutilización de objetos de aprendizaje, no proporcionan mecanismos de ensamblaje que respeten el conocimiento asociado (requisitos y
competencias) a los objetos de aprendizaje. Además, no se define un procedimiento para la descripción de los objetos resultantes de dichas integraciones mediante el uso de meta-datos (información acerca de información).
Teniendo en cuenta estos problemas, en esta tesis se propone: (i) un modelo conceptual (descrito en el capítulo 3) que proporciona las pautas para facilitar la generación, ensamblaje y reutilización de objetos de aprendizaje. Su utilización está orientada fundamentalmente a profesores-diseñadores que estén interesados en generar objetos de aprendizaje reutilizables y ensamblables.
Los objetos de aprendizaje generados con éste modelo reciben el nombre de ELOs (Electronic Learning Objects). Un ELO se define como (ver sección 3.1.1) aquel recurso educativo descrito por meta-datos y organizado en una estructura
multicapa, de tal forma que los elementos más avanzados de esta estructura incluyen conocimiento asociado (competencias y requisitos), con vistas al ensamblaje y la reutilización; (ii) un mecanismo para el ensamblaje de diferentes tipos de objetos de aprendizaje, que tenga en cuenta el conocimiento asociado a cada objeto de aprendizaje y (iii) un procedimiento para la descripción, mediante meta-datos, de los objetos de aprendizaje resultantes de los procesos de ensamblaje.
En los apartados siguientes se hace una breve descripción de los procesos de generación, ensamblaje y reutilización de ELOs, describiendo para cada uno de ellos sus características más relevantes y la forma en que se abordan las
soluciones propuestas.
Generación
En el proceso de generación se tiene en cuenta el modelo de contenido ELO (descrito en la sección 3.1), cuyos componentes conforman una estructura multicapa con distinto nivel de granularidad (N0, N1 y N2), permitiendo diferenciar las unidades atómicas de aquellas más complejas.
Las unidades atómicas se denominan unidades de información (UIs), se encuentran en el nivel de granularidad 0 y representan elementos autocontenidos y por lo tanto, altamente reutilizables. Las UIs carecen de conocimiento
asociado por lo que necesitan de un contexto que les confiera significado educativo, ya que por si solas no representan un experiencia que proporcione conocimiento al alumno. En cuanto a su utilización, son asimilables a las Assets definidas dentro del modelo de contenido de
objetos de aprendizaje SCORM [197].
Las unidades de contenido (UCs) se encuentran en el nivel de granularidad 1 y se forman ensamblando UIs, o ensamblando UIs y UCs. Las
UCs representan una experiencia educativa con conocimiento asociado. Es decir, que una UC necesita de unos requisitos para su comprensión
y proporciona unas competencias tras su comprensión. Desde el punto de vista de su utilización, las UCs son asimilables a los SCOs (Sharable Content Objects) de SCORM, con la diferencia fundamental de que las UCs tienen conocimiento asociado.
Las unidades didácticas (UDs), por su parte, se encuentran en el nivel de granularidad 2 y se forman ensamblando diferentes tipos de ELOs (UCs,
UCs con UDs, o UDs). Una UD representa el conocimiento referente a un área tras la acumulación de diversas experiencias educativas relacionadas. Desde un punto de vista centrado en su utilización, una UD es asimilable a un Content Organization de SCORM, al cual se le añade el conocimiento asociado, pero además incluyen en su estructura objetivos de aprendizaje (al menos uno asociado a cada UD), un resumen global de los conceptos fundamentales que enseña la UD y una descripción de los
mecanismos de evaluación que serán utilizados para evaluar dicha UD.
Hay dos formas de generar ELOs, una a partir de objetos de aprendizaje provenientes de herramientas externas. En este caso, para poder ser incluidos dentro del almacén de ELOs deben ser convertidos al formato ELO, lo cual implica que sean descritos utilizando meta-datos. En
particular se utiliza LOM [104] como esquema de meta-datos para la descripción de los ELOs, aunque incluyendo una extensión, con lo que
se consigue una descripción más adecuada. La otra forma de generar los ELOs es dentro del propio entorno, utilizando la herramienta que da soporte al modelo propuesto. La generación de nuevos ELOs, dentro de la herramienta ELO-Tool (descrita en el capítulo 5), se realiza mediante la introducción de los meta-datos correspondientes a cada ELO, con lo cual se obtiene un fichero xml que representa al ELO. La generación también puede verse como un nuevo proceso, el de ensamblaje, el cual se describe
a continuación.
Ensamblaje
El proceso de ensamblaje de ELOs (descrito desde el punto de vista conceptual en la sección 3.2 y desde el punto de vista de la implementación en la sección 5.2.3) se realiza mediante la aplicación de un mecanismo basado en el uso de ontologías denominado OntoGlue (descrito en la sección 3.2.2). Para comprender el funcionamiento de este mecanismo es necesario comprender los conceptos de ontología alcanzable, representación de una clase en una ontología y conocimiento cubierto, extrapolados
desde el caso básico de mappings 1 a 1, al caso de mappings 1 a n, incluyendo también la descripción del concepto de conocimiento cubierto
entre conjuntos de clases (todos ellos descritos en la sección 3.2.2).
Como parte del proceso de ensamblaje es necesario completar la descripción de los ELOs resultantes mediante el uso de meta-datos didácticos. Este proceso puede hacerse de forma automática o manual, dependiendo básicamente de la definición genérica de las diferentes categorías y sus elementos dentro del estándar de meta-datos LOM (la descripción conceptual
se encuentra en la sección 3.2.4 y la descripción desde el punto de vista de la implementación en el apéndice A). Desde nuestro punto de vista, tal definición no abarca una descripción suficiente para los ELOs, por lo cual se ha añadido una extensión (el proceso de extensión se describe en la sección 4.1.1) a dicho estándar con el fin de obtener una descripción pedagógica más adecuada, que permita dar soporte al mecanismo de ensamblaje propuesto en esta tesis. Adicionalmente y para que la descripción de los ELOs quede completa, es necesario tener en cuenta no solo las relaciones permitidas entre los diferentes componentes del modelo de contenido, sino el efecto producido al mezclar diferentes tipos de meta-datos.
La característica fundamental del proceso de ensamblaje es que el mecanismo propuesto se centra en el aprovechamiento del conocimiento asociado a los ELOs como medio fundamental para lograr el ensamblaje y la descripción de los ELOs resultantes mediante el uso de meta-datos
didácticos. Todo esto con el fin de obtener objetos de aprendizaje con un alto contenido pedagógico, ya que se potencia la definición de los requisitos y las competencias asociadas a cada objeto de aprendizaje, asegurando de esta forma un ensamblaje adecuado que respete el conocimiento asociado a los objetos de aprendizaje en cuestión.
Reutilización
Una consecuencia directa de la aplicación de los mecanismos para la generación y ensamblaje de ELOs es el proceso de reutilización. Para
dar soporte a dichos procesos se propone una herramienta (denominada ELO-Tool), concebida como un sistema para la generación, ensamblaje
(con base en el conocimiento asociado) y reutilización (de acuerdo con el mecanismo de ensamblaje propuesto) de ELOs.
La búsqueda de ELOs a través de requisitos y competencias unida a la utilización de ontologías y mappings, representa un factor potenciador de la reutilización de los ELOs.
Además, la reutilización se analiza desde la perspectiva humana, para identificar porqué y a quién le interesa reutilizar objetos de aprendizaje, y desde la perspectiva técnica para determinar cómo se lleva a cabo el proceso de reutilización y qué materiales son factibles de reutilizar (como se describe en la sección 3.3), desde el punto de vista conceptual. La reutilización desde el punto de vista de implementación es soportada por ELO-Tool).
De otra parte, ELO-Tool representa una plataforma para la evaluación de objetos de aprendizaje, ya que a través de la reutilización es posible evaluar la correcta definición de los ELOs tanto desde el punto de vista de su generación como en su posterior ensamblaje. La evaluación tiene como objetivos identificar la actitud de los profesores-diseñadores frente
a los procesos de diseño, desarrollo y selección de ELOs, y determinar lo que los objetos de aprendizaje representan para ellos y los criterios de selección que siguen a la hora de escoger los materiales digitales para la
enseñanza. El proceso de evaluación se describe en la sección 5.4.
Con el fin de comprobar la viabilidad técnica (es decir la implementación), del mecanismo de ensamblaje, se ha realizado un prototipo que
implementa el mecanismo OntoGlue Full (descrito en la sección 3.2.3 y que corresponde a la versión extendida del mecanismo OntoGlue), corroborando así su correcto funcionamiento.
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The work presented in this memory is focused on the identification of problems related with generation, assembling and reuse of learning objects. In particular, the lack of conceptual models for designing and building learning content management systems (LCMS) has been identified. Although the major part of these systems allow integration and reuse of learning objects, they do not provide assembly mechanism which take into account the associated knowledge (requirements and competencies) to the learning objects. On the other hand, do not exist a procedure to describe resulting objects from such integrations using meta-data. Taking into account these problems, in this thesis are proposed: (i) a conceptual model (described in chapter 3), which provide guidelines to facilitate generation, assembling and reuse of learning objects. Their use is focus to teachers-designers interested in generating reusable and assembling learning objects. The learning objects generating with this model are named ELOs (Electronic Learning Objects). An ELO is defined as (see section 3.1.1) an educational resource described by meta-data and organized in a multi-layer structure, which more advanced elements posses associated knowledge (competencies and requirements), with view to the assembly and reuse; (ii) a mechanism for the assembly of different types of learning objects, which take into account the associated knowledge to each learning object and (iii) a procedure for the description, by meta-data of the resulting learning objects of the assembly processes. In the following paragraphs there is done a brief description of the processes of generation, assembly and reuse of ELOs, describing for each one the most relevant characteristics and the form in which the proposed solutions are approached. Generation In the generation process there is born in mind the ELO content model (described in the section 3.1), whose components are organized in a mulvii tilayer structure with different levels of granularity (N0, N1 and N2), separating the atomic units from the more complex units. The atomic units are named information units (IUs), they are in the level of granularty 0 (N0). The IUs represent atomic elements, self-content and highly reusable. Each one of them contains a single multimedia file. These elements lack of associated knowledge. They need a context before they acquire educational significance, because in themselves do not provide knowledge to the student. From the point of view of their use, IUs are similar to the Assets defined inside the SCORM content model[197]. The content units (CUs) are in the level of granularity 1 (N1). They are formed from the assembly of IUs or assembly IUs and CUs. The CUs represent educational experiences with associated knowledge. I.e., they need requirements for their understanding and provide competencies after their absorption. From the point of view of their use, the CUs are assimilable to the SCORM SCOs (Sharable Content Objects), with the fundamental difference of CUs have associated knowledge. Finally, the didactical units (DUs)are in the level of granularidad 2 (N1). They are formed assembling different types of ELOs (CUs, CUs with DUs, or DUs). The DUs represent knowledge related to a specific area, after the accumulation of different related educational experiences. DUs also possess an associated knowledge attribute. The difference between DUs and CUs is the inclusion in DUs of extra information regarding objectives, summary and evaluation mechanism. There are two ways of generating ELOs, one from learning objects coming from external tools. In this case, they must be turned to the ELO format, using meta-data. LOM standard [104] is used as meta-data scheme for the description of the ELOs, though including an extension, which allow a more suitable description. Another way of generating the ELOs is inside the ELO-Tool environment, which provides support to the proposed conceptual model. The generation of new ELOs, inside the ELO-Tool (described in the chapter 5), is achieved introducing the appropriated meta-data, to generate the corresponding xml file. The generation can be seen as a new process, the assembly, which is described later. Assembly The process of assembling ELOs (described from the conceptual point of view in the section 3.2 and from the point of view of the implementation in the section 5.2.3) is fulfilled by means of the application of an ontologybased mechanism named OntoGlue (described in the section 3.2.2). To understand the mechanism functionality is necessary to understand the concepts of reachable ontology, representation of a class in an ontology and covered knowledge, explained from the basic case of 1 to 1 mappings, to the case of 1 to n mappings, including also the description of the concept of covered knowledge between sets of classes (all of them described in the section 3.2.2). Since part of the assembly process is necessary to complete the description of the resultant ELOs by means of the didactic use of meta-data. This process can be done of automatic or manual form, depending basically on the generic definition of the different categories and their elements inside the standard LOM (the conceptual description is in the section 3.2.4 and the description from the point of view of the implementation in the appendix A). From our point of view, such a definition does not include a sufficient description for the ELOs, by which has been added an extension (the extension process is described in the section 4.1.1) to the above mentioned standard in order to obtain a more suitable pedagogic description, which allows to give support to the assembly mechanism, proposed in this thesis. In order to provide a more complex description of the ELOs, it is necessary to take into account the relations allowed between the different content model components, and the effect produced by the mix of different types of meta-data. The fundamental characteristic of the assembly process is that the proposed mechanism centres on the use of associated knowledge to the ELOs as fundamental way to achieve the assembly and the description of the resultant ELOs by means of the didactic use of meta-data. All that in order to obtain learning objects with a strong pedagogic content, since there are promoted the definition of the requirements and competencies associated with every learning object, assuring of this form a suitable assembly that should respect the associated knowledge to the learning objects in question. Reuse A direct consequence of the application of the mechanisms for the generation and assembly of ELOs is the reuse process. To give support to the above mentioned processes a tool (named ELO-Tool) is proposed. This tool is a system for the generation, assembly (based on associated knowledge) and reuse (in agreement with the assembly mechanism) of ELOs. In addition, the possibilities of reuse ELOs are increases by the searching across requirements and competencies joined the use of ontologies and mappings. Besides, the reuse is analyzed from the human perspective, identifying why and who is interested in reusing learning objects, and from the technical perspective to determine how is achieve the reuse process and what materials are feasible of reusing (as it is described in the section 3.3), from the conceptual point of view. The reuse from the point of view of implementation is supported by ELO-Tool). From the other hand, ELO-Tool represents a platform for the evaluation of learning objects, since across the reuse it is possible evaluate the correct definition of the ELOs from the point of view of their generation and later assembly. The evaluation allows to identify the attitude of the teachers-designers respect to the processes of design, development and selection of ELOs. This process determine what the learning objects represent for them and the selection criteria using to choose the digital materials. The evaluation process is described in the section 5.4. In order to verify the technical viability (implementation), of the assembly mechanism there has been realized a prototype that implements the mechanism OntoGlue Full described in the section 3.2.3 and that corresponds to the widespread version of the mechanismOntoGlue), corroborating in this way its correct functioning.
The work presented in this memory is focused on the identification of problems related with generation, assembling and reuse of learning objects. In particular, the lack of conceptual models for designing and building learning content management systems (LCMS) has been identified. Although the major part of these systems allow integration and reuse of learning objects, they do not provide assembly mechanism which take into account the associated knowledge (requirements and competencies) to the learning objects. On the other hand, do not exist a procedure to describe resulting objects from such integrations using meta-data. Taking into account these problems, in this thesis are proposed: (i) a conceptual model (described in chapter 3), which provide guidelines to facilitate generation, assembling and reuse of learning objects. Their use is focus to teachers-designers interested in generating reusable and assembling learning objects. The learning objects generating with this model are named ELOs (Electronic Learning Objects). An ELO is defined as (see section 3.1.1) an educational resource described by meta-data and organized in a multi-layer structure, which more advanced elements posses associated knowledge (competencies and requirements), with view to the assembly and reuse; (ii) a mechanism for the assembly of different types of learning objects, which take into account the associated knowledge to each learning object and (iii) a procedure for the description, by meta-data of the resulting learning objects of the assembly processes. In the following paragraphs there is done a brief description of the processes of generation, assembly and reuse of ELOs, describing for each one the most relevant characteristics and the form in which the proposed solutions are approached. Generation In the generation process there is born in mind the ELO content model (described in the section 3.1), whose components are organized in a mulvii tilayer structure with different levels of granularity (N0, N1 and N2), separating the atomic units from the more complex units. The atomic units are named information units (IUs), they are in the level of granularty 0 (N0). The IUs represent atomic elements, self-content and highly reusable. Each one of them contains a single multimedia file. These elements lack of associated knowledge. They need a context before they acquire educational significance, because in themselves do not provide knowledge to the student. From the point of view of their use, IUs are similar to the Assets defined inside the SCORM content model[197]. The content units (CUs) are in the level of granularity 1 (N1). They are formed from the assembly of IUs or assembly IUs and CUs. The CUs represent educational experiences with associated knowledge. I.e., they need requirements for their understanding and provide competencies after their absorption. From the point of view of their use, the CUs are assimilable to the SCORM SCOs (Sharable Content Objects), with the fundamental difference of CUs have associated knowledge. Finally, the didactical units (DUs)are in the level of granularidad 2 (N1). They are formed assembling different types of ELOs (CUs, CUs with DUs, or DUs). The DUs represent knowledge related to a specific area, after the accumulation of different related educational experiences. DUs also possess an associated knowledge attribute. The difference between DUs and CUs is the inclusion in DUs of extra information regarding objectives, summary and evaluation mechanism. There are two ways of generating ELOs, one from learning objects coming from external tools. In this case, they must be turned to the ELO format, using meta-data. LOM standard [104] is used as meta-data scheme for the description of the ELOs, though including an extension, which allow a more suitable description. Another way of generating the ELOs is inside the ELO-Tool environment, which provides support to the proposed conceptual model. The generation of new ELOs, inside the ELO-Tool (described in the chapter 5), is achieved introducing the appropriated meta-data, to generate the corresponding xml file. The generation can be seen as a new process, the assembly, which is described later. Assembly The process of assembling ELOs (described from the conceptual point of view in the section 3.2 and from the point of view of the implementation in the section 5.2.3) is fulfilled by means of the application of an ontologybased mechanism named OntoGlue (described in the section 3.2.2). To understand the mechanism functionality is necessary to understand the concepts of reachable ontology, representation of a class in an ontology and covered knowledge, explained from the basic case of 1 to 1 mappings, to the case of 1 to n mappings, including also the description of the concept of covered knowledge between sets of classes (all of them described in the section 3.2.2). Since part of the assembly process is necessary to complete the description of the resultant ELOs by means of the didactic use of meta-data. This process can be done of automatic or manual form, depending basically on the generic definition of the different categories and their elements inside the standard LOM (the conceptual description is in the section 3.2.4 and the description from the point of view of the implementation in the appendix A). From our point of view, such a definition does not include a sufficient description for the ELOs, by which has been added an extension (the extension process is described in the section 4.1.1) to the above mentioned standard in order to obtain a more suitable pedagogic description, which allows to give support to the assembly mechanism, proposed in this thesis. In order to provide a more complex description of the ELOs, it is necessary to take into account the relations allowed between the different content model components, and the effect produced by the mix of different types of meta-data. The fundamental characteristic of the assembly process is that the proposed mechanism centres on the use of associated knowledge to the ELOs as fundamental way to achieve the assembly and the description of the resultant ELOs by means of the didactic use of meta-data. All that in order to obtain learning objects with a strong pedagogic content, since there are promoted the definition of the requirements and competencies associated with every learning object, assuring of this form a suitable assembly that should respect the associated knowledge to the learning objects in question. Reuse A direct consequence of the application of the mechanisms for the generation and assembly of ELOs is the reuse process. To give support to the above mentioned processes a tool (named ELO-Tool) is proposed. This tool is a system for the generation, assembly (based on associated knowledge) and reuse (in agreement with the assembly mechanism) of ELOs. In addition, the possibilities of reuse ELOs are increases by the searching across requirements and competencies joined the use of ontologies and mappings. Besides, the reuse is analyzed from the human perspective, identifying why and who is interested in reusing learning objects, and from the technical perspective to determine how is achieve the reuse process and what materials are feasible of reusing (as it is described in the section 3.3), from the conceptual point of view. The reuse from the point of view of implementation is supported by ELO-Tool). From the other hand, ELO-Tool represents a platform for the evaluation of learning objects, since across the reuse it is possible evaluate the correct definition of the ELOs from the point of view of their generation and later assembly. The evaluation allows to identify the attitude of the teachers-designers respect to the processes of design, development and selection of ELOs. This process determine what the learning objects represent for them and the selection criteria using to choose the digital materials. The evaluation process is described in the section 5.4. In order to verify the technical viability (implementation), of the assembly mechanism there has been realized a prototype that implements the mechanism OntoGlue Full described in the section 3.2.3 and that corresponds to the widespread version of the mechanismOntoGlue), corroborating in this way its correct functioning.
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Keywords
Tecnología educativa, Internet en la enseñanza, Educación a distancia