A schema presenting how Personal Learning Environment and Personal Learning Network cooperate in our DIEL System. The main components of DIEL live in Layer1, the PLE builds Layer 2 and the final layer combines all the functionalities for the PLN. 

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Context 1

... aggregations can be considered as sets of connections between elements (contents) in a PLE. For instance, an aggregation could encompass some blog entries, a Google Docs presentation and a portion of the slides from a specific course. The platform will then show a line that connects all resources icons together. Such links can be labeled, to highlight relationships among contents, and the aggregation itself can be attached a label, and an arbitrary number of tags, as for all PLE-managed elements. To simplify search and management of aggregations, they can be listed in a specific menu, while to avoid confusion, links can be selectively displayed or hidden. Similarly, aggregations can be collapsed to one icon, or else, all their components can be expanded and shown in the 3D space, as described, later, in Section 5. Sharing contents aggregations can be achieved as a one-to-one mechanism, or as a one-to many mechanism, respectively using the Communication or the Feed Reader component. What is actually shared is a link to the internal representation of the contents aggregation, a ReST URL. In one-to-one communication, such an URL is sent , per chat or email, to another user, who will be able to view and eventually import it. In one-to-many communication, users can share a RSS feed (containing a set of such links), advertising all own aggregations; this mechanism will automatically update feed subscribers about new aggregations, thus allowing them to import newly created elements in their own PLE. According to the recent book of Kapp and O’Driscoll in [17], it’s just a matter of time until 3D virtual immersive environments will be accepted as the learning mode of choice. Understanding the cognitive advantages underlying this idea is still under study. However, a 3D learning experience (3DLE), can be considered as rich interactive space in which the learner lives and interacts in real-time within an immersive virtual environment and community. In a well-designed 3DLE, learning is transformed from a one-dimensional, directed and managed activity to a multi-dimensional collaborative activity. Through this approach, learners create shared meaning together. Thus, accomplishing a series of tasks in a virtual environment creates an ideal learning experience. It connects the visual and mental cues that make the recall and application of the learning more effective [13,17]. Thinking about this, it’s straightforward to understand why we have decided to adopt a 3D space metaphor in order to represent PLE and PLNs. We strongly believe that 3D virtual worlds can be as support in the personal learning processes, as also suggested by the very active research and business going on game-based and serious learning, as for example in [1,3,19]. Also, games intrinsically use a constructivist approach as students are meaning-makers and meaning-making results in production [16]. As hinted in the previous Section, we decided to arrange resources available in a PLE as 3D icons in a 3D space, with specific semantic meanings attached to icons themselves, to their visible links, and, as will be described in the following, also to their positioning. Contents aggregations can be collapsed inside one box, which contains all the resources, the relationships and the tags defined by the user in the learning process. The graphical representation of the expanded content aggregation is a 3D hypergraph in which nodes represent resources and links represent the way in which these resources are connected each other. The corresponding syntax can be in the form of RDF triples "A in-relation-B-with C" where all the elements "A,B,C" can have semantic tags and specific meaning associated. Tags attached to a resource or a link can be hierarchically organized and can be semantically enriched by the learner ( very important , read also , interesting , and so on...) or simply devoted to statistical usage of the resource itself (number of accesses, last access, and so on...). The combination of the values of these tags automatically promotes the resource in the contents aggregation (box) as more or less relevant with respect to the other resources in the same box. The Recommender System, shown in Fig. 2 at Layer 2, is the PLE component that manages this process on behalf of the individual user. An avatar, representing the learner, can move freely in the space interacting with the resources or the boxes (contents aggregations) moving them from one place to another, thus associating specific importance (meaning) to the spatial position of an element. The learner can drag an interesting resource in the space, positioning it in one or more existing boxes, or creating a new box for a new contents aggregation. The 3D environment supports a complete view of the learning space which can render complex inter-relationships among resources. Sharing contents aggregations, or portions of them, with other users is also implicitly achieved by moving their icons to a specific place. Once an element is shared, the learner collects feedback from colleagues, since they may enrich the tagging of the element; she may then accept or reject such suggestions from others. This way, social knowledge is created inside the PLN. Thus, we decided to design the PLE view in DIEL as a portion of sky (see Fig. 3). The aim of this representation is to mark the difference between a structured learning environment, organized as a set of rooms belonging to a learning path, and a user- managed space, focused on personal interests. Choosing a sky as “container” of PLE resources and links is an intuitive metaphor of user's freedom. In our current PLE implementation, and per default, PLE elements are placed along a spiral, in the middle of the sky. This disposition links to the time that passes by, such that newer resources are arranged on top of older ones. The default spiral does not keep into account contents aggregations, as it is mainly aimed at focusing the person's attention to newer elements in PLE, that probably are the most interesting, and that deserve further study. By focusing on a particular contents aggregations, it is again rendered in PLE view as a distinguished spiral, like in Fig. 3. It is convenient to employ translucence and proximity inside PLN with a semantic meaning. Translucence, as suggested by [11], can be used to explore peers PLEs and find out selected resources for extending own PLE. This mechanism is especially useful for the novices approach to new topics, to find materials made visible outside their PLE by peers. Translucence, however, would not be sufficient to gather the relevant materials, since the default arrangement inside PLE is based on temporal relationships. To this purpose, we need a further feature, namely, to be able to arrange icons in the 3D space based on tag matching. Upon request, users can sort resources with same tags so that they can be naturally placed close to one another, and proximity may be used to approach resources collected by peers having similar tags. This spatial organization is based on the information collected by the Recommender component, that promotes (or demotes) resources that peers have chosen (or neglected) by showing them closer (or far away) from the user focus of interest. DIEL users produce different pieces of information, that are mainly used by the Recommender component. Some of them are directly connected with 3D visualization, others with contents, namely the use of tags and links that ...

Context 2

... our work, we took into consideration this (enough broad) definition, first because it is one of the firsts officially provided, and second because it does not seem to prevent neither any application nor future developments. Thus, a PLE can be seen as a network of websites and/or services, that individuals – users, students – use to acquire new information and to deepen their knowledge on specific topics: in a word, to learn . PLE users read, store and maintain precise contents and, at the same time, produce learning contents or reflections, also recording documentations about their particular and personal learning processes. In addition, PLE users aggregate data from their learning communities, using Web 2.0 technologies, RSS feeds or interesting Web logs (blogs). Fig. 1 shows a PLE, according to Weller [22]. Today, there is still no widespread use of PLEs, not so much for lack of available technologies for searching, storing, and annotating web based resources, but mostly for the difficulties experienced in the practical organization of these resources into a coherent and useful learning space . As presented so far, a PLE is tightly connected to the person whom it belongs; it is of course up to her to “run” and “maintain” the environment, i.e., to keep track of all different knowledge sources, and to monitor and access them periodically. These housekeeping tasks can be simplified to a certain extent using RSS feeders, nevertheless they shall require much effort and time to the learner. But obviously, at this stage of development, manual activities are necessary, thus requiring effort and concentration from the user. As a further remark, the added value of many pieces of information, which originally were made available from non-related web sources, lies in establishing new, explicit relationships among them. This idea of linking together information, and tagging them as well as the respective links, is a central one in our system, and shall be further elaborated in the following Sections. Personalization and freedom are sometimes criticized, because these forms of unstructured learning do not guarantee the quality of collected information. Therefore, absolute beginners in a topic may find a problem in using a PLE, given their difficulties to recognize authoritative information. To overcome in part such an issue, significant contributions to understand the trustworthiness of different knowledge sources may be provided by the observation of relevant resources, ranked as such by a majority of peers in a community, or by its relevant members. To this respect, it is of vital importance for a PLE to be translucent , as defined in [11]. Translucence is implemented by creating a graphical representation of a virtual space, containing the users of such application as well. As a consequence, PLE visualization should help the learner to understand how his/her community is interacting at any given instant. The implications of translucence, and its extension to social translucence, in learning environments have been extensively discussed in [6]. Inside PLE, social translucence requires at least a part of each learner's PLE to be visible to peers, thus encouraging cooperation and knowledge sharing. These considerations come from different requirements, just partially related to technical aspects of content fruition. Searching material on the Web is a complex activity, that involves various mental processes. PLE content selection is particularly relevant, because it implies an important reflection that leads to meta-cognitive operations , needed for understanding how to link a specific content to the existing knowledge background of a person. This topic is being investigated by various authors [12,18], that underline the value of tagging in self-directed learning as means for stimulating reflection on the tagged materials and their topics. Combining and extending the concept of PLE, a Personal Learning Network, PLN for short, consists of the people (or better, the set of PLEs of the people) a learner interacts with and derives knowledge from in a Personal Learning Environment. The concept is new but promising and, somehow, related to the theory of connectivism [10, 20]. In fact, learners in a PLN create connections and develop a network that contributes to their professional development and knowledge. In the last years, the concepts of PLE and PLNs are raising attention as possible important part of professional development in several fields. They have become common subjects in research for education and e-learning. DIEL is an e-learning platform providing new ways of user interactivity and data representation in a web based real-time environment [7, 8]. DIEL provides a dynamic and interaction-friendly virtual learning space for community portals in education. Its effectiveness was experienced in high schools, university courses, and in vocational training. DIEL supports educational strategies involving collaborative activities, as recommended by socio-constructivistic pedagogists, as well as individual and personalized learning strategies. The organization of a learning activity is like the exploration of a set of virtual rooms, each of these rooms being dedicated to a specific activity. This metaphor mimics the real life, where there is a natural mapping between places and activities, like for example a library, a laboratory, or even a cafeteria. Available resources for the given learning objective appear as objects inside a room. The tutor decides room appearance and topology, by placing inside them, among possible objects, some doors, that lead to other rooms. DIEL is web-based, built upon Moodle, and by design, its user interface, functional process logic ("business rules"), computer data storage, and data access, is developed and maintained as independent modules, thus as a three-tier architecture. The Data Layer is responsible for storing and retrieving all the information needed for the e-learning platform and processes, as for example resources (multimedia data) and pre-defined learning paths. The Business Logic controls the application functionalities by performing detailed processing. The Presentation Layer, which is the topmost level of the framework, is devoted to displaying information by outputting processing results to any HTML5 browser/client [7]. The choice to develop DIEL as an environment for experiencing new technologies in education on top of Moodle responds to two main criteria: (i) the practical consideration that Moodle already has a huge community of users (as of Oct. 2011, more than 57000 registered sites offering more than 5 million courses, with more than 1 million teachers and 48 million learners, speaking 78 languages); (ii) the availability of an open source developers community around it, and the possibility to distribute our extensions back to the community itself. Our idea of a Personal Learning Environment in DIEL relies on the design and definition of environments – evolving in time – in which users can keep and organize their own resources, such as chat messages, documents, web links or other multimedia and digital contents [5]. As shown in Fig. 2, the PLE layer in DIEL is built upon the central layer which includes the basic modules and implements the main functionalities of our system, as defined in [8]. The outermost layer is conceptually belonging to PLN, and its role shall be clarified later in this section. The PLE layer upon DIEL core is also organized into different components, each of them delegated to specific ...