Exploiting context-specific content for better reuse of existing teaching and learning materials Maik Bunschkowski, Marc Röser, Djamshid Tavangarian, Denny Voigt University of Rostock (Germany) Institute of Computer Science
Key words: personalized documents, context-specificity, reuse, content adaptation Abstract: A well-known problem in reusing electronic teaching and learning materials is the fact that the aggregation level of content strongly influences its reusability in other contexts. The conflictive requirements of reusability and aspect-orientation are obviously leading to difficulties with the aggregation of existing content into more comprehensive materials. This paper shows an approach for resolving this conflict bringing already existing materials into a new context, which is arranged from additional content. In that way, transitions between the different parts of the newly generated material can be manually smoothed, e.g. respecting writing styles and intentions of the authors. This procedure allows for the consideration of convergences between the different matters as well as didactical and pedagogical aspects.
1 Introduction The creation of high quality, multimedia teaching and learning materials (TLM) is very resource intensive with respect to time and money [1]. Baumgartner [2] estimates the costs of one hour of interactive content to be in the range of 2.000 – 20.000 Euro and even more, depending on the amount of multimedia content and the respective subject. As most people will agree, in our current world goods are not created without a working sales concept, allowing for a potentially maximum return on investment (ROI). Homogenized TLM for the typical learner and reusability of already existing teaching and learning materials are the key to these two concepts. Alas, such commercial considerations are not always suitable for sensible areas like the educational domain, which is a realization, proven by a number of misguided e-learning projects dating back to the so-called e-learning hype [3]. For that reason scholars and researchers have recently begun the analysis of the basic building blocks of elearning that are leading to the exploration of possible solutions. For that reason this contribution starts with creating a basic understanding of the central building block of e-learning – the learning object. Based on that foundation, the commercial concept of reuse of learning object is introduced and an inherent paradox is disclosed. Because of the important influence of that paradox on the quality and acceptance of digital TLM, requirements are formulated, which shall assure these characteristics. Finally a practical realization of the conceptual requirements is demonstrated, which shows their practical fitness and applicability. It should be clear that with this contribution the authors are suggesting only one possible way out of many thinkable as a basis to assuring high quality teaching and learning materials.
2 The learning object There exists a large number of definitions and taxonomies for the concept of learning object [4], [5]. One, perhaps the best known and most accepted, definition originates from the Learning Technology Standard Committee (LTSC) of the IEEE. Speaking with their words, a learning object is “any entity, digital or non-digital, which can be used, reused or referenced during technology supported learning” [6]. The somehow sloppy formulation of the IEEE is nevertheless inherently containing the destined areas of application – the use, reuse and referencing of learning objects. In the eyes of the learning objects community, the accessibility, availability and interoperability are regarded as further functional aspects [7], whereas the goal of reuse is the main aspect in most of the definitions for learning objects. In the following, the term reuse will be used in the context of being the degree, up to which a learning object can be utilized in more than one learning scenario. Maximum reusability requires relatively small and independent fragments instead of a single monolithic learning object, which therefore has to be modularized – so to say scattered – into as many as possible small elements [8], [9]. These resulting fragments (atomic learning objects) should be self-contained and follow a certain goal. In literature, the size and also range of a learning object is dealt with under the synonym granularity [10]. Another important side-effect of the mentioned scattering is the de-contextualization [9], [11], which simply means that a learning object is removed from its original context and thus made semantically and technically independent of other learning objects. Context-specificity designates the degree, up to which a learning object is embedded into a specific context. The context of a learning situation contains in example the experiences and interpretations of the creator of the learning object. Hence, the object can only be useful for those addressees, for whom that creation context is comprehensible. For learning objects to be universally applicable and thus not limited to a certain subject or learning context, the process of decontextualization has to be carried out in advance. Most importantly, the modularization of monolithic resources is fostering the extraction of atomic, de-contextualized learning object fragments. In analogy to children’s building blocks the recombination of fragments to new learning objects of a coarser granularity is an important e-learning methodology. On the technical side, this kind of reuse is realized by describing the respective learning objects with metadata and then harnessing the descriptions of semantic and logical interdependencies, encoded inside the metadata sets, for further abstraction and recombination at higher granularity levels (see Figure 1). Finally this “construction kit” [12], [9] metaphor is based on the recombination of learning objects to a new learning unit with a certain goal, which in literature is often also called “aggregation”. The corresponding aggregation can be realized manually, in a semi- or even fully automatic kind.
Learning Objects
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Term Figure 1: Building block principle (see also [3]) 2.1 Paradox: context-specificity and reusability An aggregation that is consisting of a number of loosely linked context-free learning objects has to be seen from a skeptical point of view when the question of pedagogically and didactically demanding contents arises. It has to be argued, that the claim for context-free learning objects is not realizable because every created learning object is assembled for certain purposes and audiences. It follows an inherent intention and hence cannot be examined without respecting its context. For that reason, in the following the term of weakly contextualized learning objects (WCLO) is utilized for referring to such objects. Even the claim for WCLOs is subject to controversies between followers of the constructivist and instructivist paradigms. Traditional learning resources, such as books, are rather instructivistic because related learning materials are presented, following the principle of linearity, in a logically structured way. In that case, linearity does not only have the meaning of a simple line-up of contents to be imparted, but is rather a synonym for an implicitly logical, coherent chain of thematically related learning units. This is leading to the conclusion, that de-contextualization has to be avoided for instructivism where it would be in direct opposition to the intended reuse of learning objects in different contexts. On the other hand, constructivist learning theories regard the context of a learning situation, also named “situated learning”, as a precondition for the inner construction of meaning [13] and the comprehension of the respective learning objects. In moderate constructivism, a certain amount of context-specificity is accepted as helpful and unavoidable [3]. As a slightly exaggerated example, one could examine a learning object that is an aggregation of encyclopedic entries, related to a certain topic. It should be obvious that such a learning object cannot be designated as learning material of high didactical quality, because it lacks a context-specific introduction for the learner, allowing for getting familiar with the new subject matter. Furthermore, introducing explanations are not only necessary for the creation of a basic understanding of a new topic but also significant for an effective learning style. Context-specific information is not only relevant for the introductory part of a learning object but also for any other section of it. Additionally, information mediating between atomic learning objects can foster connections between the learning content, previous experiences and the knowledge base of the learner. That is why the involvement of context-specific information is essential for a successful and efficient learning style.
2.2 Paradox: personalization and reuse The term personalization of learning materials is usually indicating an adaptation of content to certain learners or learner types. In the context of this paper, adaptation means the flexible combination of atomic learning objects to new aggregations that are tailored for the personal knowledge background of the respective learner. Baumgartner is provokingly asking why one should visit an online course of about two hours, if fifteen minutes would have been enough time for the filling of an individual knowledge gap [2]. As an answer one could argue that the manual and automated assembly of such aggregations is a very complex and demanding area of current research [14], [15]. But despite all efforts, all of the assembled aggregates lack an adaptation to the learner himself, which is really necessary for fulfilling the high requirements of personalized learning materials. Such a personalization makes it unavoidable, to directly address the learner or, more generally, the intended audience of a WCLO with explanations why the learning object is suitable for that certain learning goal and target audience. Additionally the teacher should have an opportunity to brand the learning material with respect to himself and his institution, respectively. That is why a personalization must not be limited to the learner’s side but has to be possible on behalf of the teacher’s as well. 2.3 Context information As previously stated, context-free, atomic learning objects are not adequate for didactically valuable learner support, because that would require contextualization, complicating the reuse of materials. One possible solution to that problem could be the creation of additional contextspecific information with the purpose of smoothing contextual breaks between the respective WCLOs in mind.
3 Realization of context information in practice In the following section, a real-life scenario of application for the aforementioned conception is introduced. In it a practical implementation of re-contextualization is developed and evaluated, respecting its power for semantically enriching course structures, consisting of selfcontained learning objects. It will be shown how the described implementation can influence the reception of teaching and learning materials as well as the quality of e-education in general. 3.1 The WWR-Project During the course of the 2001 started joint project “Knowledge factory Computing Systems” (WWR) [16] a building block repository of multimedia, multidimensional and recombinable teaching and learning modules from the scientific domain of technical computer sciences was created. In contrast to other attempts that usually recombine fragments of a very small granularity to complex aggregations, the WWR-modules are of coarse granularity and selfcontained. For clarification it may be stated that every single module takes up to twelve hours (eight hours lectures and four hours practical work and tests) for processing. In that way, it is assured that a certain topic can be completely contained in such a module. Its complexity can be adapted by employing the so-called module dimensions that allow for a modification (also called scaling) with respect to the target audience, scenarios of application and difficulty levels. The flexibility, achieved by that mechanism, is directly based on the XML vocabulary ³ (Multidimensional LearningObjects and Modular Lectures Markup Language) [17], which is utilized for the implementation of the modules’ content. The WWR-specific module dimensions are depicted in Figure 2a.
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Figure 2: a) Module dimensions, b) and c) example module instances By employing the different module dimensions, eighteen different module instances can be generated from a single, abstract ³ description. These instances are differing with respect to their intensity, as ³ allows for simple, advanced and expert difficulty profiles, with respect to their target audience, where teachers or learners are possible dimension values and with respect to their scenario of application. For that dimension the occurrences as printable manuscripts, slide sets and online variants with self test exercises are defined by default. In the Figures 2b and 2c two possible module instances are exemplarily. Because one module is limited to a certain topic, the assembly of complex courses from single modules, allowing for the dealing with bigger topical complexes is possible. The courses themselves are also described in XML. The respective descriptions contain, next to the usual information (or metadata) concerning author, creation date etc. an arbitrarily large sequence of modules with their designated intensities. Such course descriptions can also be scaled according to the desired application scenarios and target audiences in a way that is allowing for six different course instances created from one abstract course description. The course creation process is depicted in Figure 3.
Figure 3: The course creation process 3.2 The AMG-Project As the module repository of the WWR-Project is getting completed by more and more new modules, it is becoming more difficult for lecturers and teachers to manually retrieve relevant modules and assemble the respective courses. The project “Automated Manuscript
Generation” (AMG) [18] is dealing with the development of a solution for that complex task, as its goal is the adaptive, automated assembly of TLM, manuscripts and courses from the WWR-repository’s modules with respect to user specifications. For making that task soluble, an adequate description of the mentioned ³ modules with metadata is unavoidable. During the definition of an appropriate metadata set, an extension to the LOM-specification was defined [19]. This extension is including specifications for the description of intermodule relationships and similarities in terms of the respective topics of the modules and module instances which allows for the automated assembly of the aforementioned complex courses. The manuscript generator employs the users’ requirements for determining the start as well as the end module of a course and calculates a learning path by the help of the metadata encoded module descriptions, which can be interactively and iteratively optimized by the user. 3.3 System architecture All functionality that is required for the creation of modules and courses is accessible in a reference portal that is providing a web based graphical usage interface (GUI) for the ³ middleware [20]. This middleware forms a service-based abstraction layer that is acting as a broker between the module repository on one side and client-based applications on the other. Figure 4 is providing an overview of its components. The middleware provides the following functionality for module creation: -
upload and versioning of modules, automated metadata extraction and metadata authoring environment (SAMAT, [21]), generation of the presentation formats with respect to the ³ dimensions, quality assurance for content and metadata through reviewing and automated validation procedures.
The course creation is supported by keywords based module retrieval and manual or automatism-supported course assembly.
3 Middleware
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3 Module Sources and Media Files Repository
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Figure 4: ³ middleware architecture
Users, Courses, Literature, Glossary, Abbr.
3.4
Bridge-Modules
Modules, combined to a course, do not have to originate inevitably from the same source, e.g. one author, respectively team of authors or an institution. Furthermore, it is imperative, that each module for itself represents a unit. It exhaustively and broadly deals with a topic and has no, except for its assigned metadata, direct relationship to other modules. Within a certain course instance, generated from such a course description, gaps regarding writing and explanation style, used notation of formal expressions as well as different approaches and perceptions in content and didactic-pedagogical manner can be noticed between the crossovers from one module to the next. Gaps are also possible as regards content, which normally appear, if no thematic connection between two modules is given. These aspects of course adversely affect the quality of the generated teaching and learning materials. One consequence is that the user acceptance suffers. These problems cannot be solved entirely without reengineering a course from the scratch in terms of its intended purpose, style, didactical orientation etc. Thus, a reuse of existing materials, e.g. the modules within the repository, cannot be guaranteed. Moreover, the needed efforts would be unjustifiable. One possibility to approach this problem would be the description of the modules’ characteristics resulting in gaps using proper metadata. That way, these metadata could be accounted for the course creation and hence well-fitting modules, regarding their characteristics, would be composed to a homogenous course. Apart from the fact that potentially thematic gaps could not be removed with it, this approach fails at it, because modules within a repository, which cover the same content, but are characteristically different, are very hard to find. If there is a high quality module for a specific subject, scarcely anybody will start out to create a module for the same subject, which only differs in some characteristics. At the moment, the possibility to find two such modules in a repository or network of repositories, which can be accessed by one person or automatism in all, is very low. Hence, within the scope of the two mentioned projects, there was researched for an acceptable as well as workable solution, for both the course creators and the users, which resulted in the utilization of so called bridge-modules. A bridge-module is a content fragment aligned to a specific course, which stands before or after a regular module or between two of them, and which should help to smooth gaps between the modules of a course acceptably. In addition, particular course sections can be motivated, introduced or resumed with bridge-modules. For implementation purposes a bridge-module is nothing more than a module description conforming to ³, but limited to one main section and essential content types. Thereby, a bridge-module can be transformed into the needed presentation instances like a regular module, with help of the existing tools. Because of its context-specificity, a bridge-module can only be used reasonably within the corresponding course; the bridge-module’s description is contained in the course description, while regular modules will be referenced (see Figure 5). The creation of bridge-modules is done by the course creator at the time of the course composition. For this purpose, the web based usage interface was extended by an easily to be used editor, which allows for a comfortable definition of the inner structure and contents of the respective bridge-module. A screenshot of this authoring environment is depicted in Figure 6. Once created, the bridge-module can be arbitrarily repositioned and edited. Furthermore, the authoring environment allows for a preview of the current bridge-module without the need to transform the full course.
Figure 5: Course description with bridge-modules
Figure 6: Screenshot of the bridge-module authoring environment
3.5 Evaluation In the context of the AMG and WWR projects, bridge-modules allow for the smoothing of semantic gaps between adjacent modules of a course, by enriching it with context-specific information. By harnessing this option, course creators have the opportunity to explicitly point out changes in notation or style or to explain a different didactical methodology (like
changes in the frequency of self-test exercises). In addition to that obvious advances, they allow for a further structuring of the respective course by adding motivations, conclusions and the like to course descriptions. Bridge-modules are also easing the creation of personalized courses for certain learner groups or even single learners by the addition of specially tailored information. As it has been shown, bridge-modules are extremely context-specific by design. In most cases this fact is the reason for suchlike enriched courses to be limited to a small number of application scenarios, while courses without bridge-modules are more universally applicable with the obvious drawbacks, concerning their semantic quality. Luckily this limitation does not have to be a disadvantage of the proposed utilization of the bridge-modules technology because it is by all means possible to create special course variations, being enriched with bridge-modules, for certain application scenarios and target audiences without loosing the originally assembled courses. Current research activities investigate up to which extent the reuse of bridge-modules provides with advantages against the creation of new “semantic cement” for every application. If on the one hand, for example, a single bridge-module is used again and again as an introduction for a certain module, it should perhaps be made part of that module. But on the other hand, bridge-modules could contain contact information regarding the course creator and hence could be successfully utilized in many different course constellations without being of real use inside the respective modules. In these cases, reuse of these bridge-modules would be strongly advisable but also would imply additional organizational efforts, because repository functions for bridge-modules would be as necessary as for regular modules.
4 Conclusion and future work The commercially motivated intention of the broad reuse of learning objects implies a number of conceptual difficulties. One possible solution, respecting the goal of reuse, is the modularization of teaching and learning materials, an alternative being widely employed in current e-learning projects. Alas, modularization is causing de-contextualization, which concludingly leads to weakly contextualized teaching and learning materials. These can be used in the most differing application scenarios because of their resulting neutral form. Finally, this neutrality is limiting the materials’ didactical expressivity and effectiveness. If modularized TLMs are available, manual or automated processes can be employed for the synthesis of more complex aggregations out of atomic learning objects. Alas, this procedure is also leading to semantic and contextual gaps between the respective modules, which can be smoothed or even closed by context-specific cement. During the course of two German research projects (AMG and WWR), the importance of the removal of these gaps was realized and practically achieved by the introduction of so-called bridge-modules. These bridge-modules have to smooth the gaps between adjacent modules in a course structure and re-introduce context-specificity for special application scenarios. The technical implementation of all components, being necessary for the creation and management of those bridge-modules has lead to a web based authoring environment, which assures the acceptance by the course authors because of its task-oriented and intuitive usage interface. The current implementation of bridge-modules is limited to ³ modules and the aforementioned reference portal. But as the de-facto standard SCORM [22] is getting used in
more and more application scenarios, a generalization of the proposed technology seems necessary. The SCORM facilitates the integration of all thinkable resource formats in one packaging format, which is currently lacking a way for smoothing semantic and contextual gaps between the respective parts. Therefore, the authors strongly believe that it should be investigated in further research efforts, how a bridge-module like mechanism could be integrated into the SCORM and which formal criteria have to be fulfilled for doing so. As it has been shown in this contribution, it will be a long way until the realization of the commercial dream of universal reuse of once created teaching and learning materials but whatever that realization will look like, it certainly has to allow for pedagogical customizations to be advantageous in comparison to traditional ways of teaching and learning.
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Authors: Maik Bunschkowski, Dipl.-Inf. University of Rostock Institute of Computer Science Chair of Computer Architecture Albert - Einstein - Strasse 21 D - 18059 Rostock
[email protected] Marc Röser, Dipl.-Kfm.
[email protected] Djamshid Tavangarian, Prof. Dr.-Ing. habil.
[email protected] Denny Voigt, Dipl.-Inf.
[email protected]
