This thesis will discuss a knowledge-based model for the design and development of units of learning and teaching aids. The idea behind this work originates from previous theoretical work on ECM - Educational Concept Map (a logical and abstract annotation system, derived from the theories of instructional design), from the open issues in designing instructional authoring system, and from the lack of a well-defined process able to merge pedagogical strategies with systems for the knowledge organization of the domain.
Teaching and learning have undergone profound changes in recent years, partly a
consequence of the evolution of learning theories, in part dependent on the
development and evolution of network technologies. The emergence of constructivist theories
of learning models [
The basic idea that drove this PhD thesis starts from this awareness. The final goal is the definition and development of a knowledge-based model for instructional design with specific focus on educational content designed, to be used in e-learning environments, taking into account the perspectives of development that appears to promise the web today, grounded also on a pedagogical reflection and scientific knowledge we have today.
The approach proposed in this thesis finds its foundation in the work of those who in recent decades have addressed the problems underlying the processes of learning on the one hand and the other knowledge representation, with particular attention to the area of research that goes under the name of the semantic web.
The specific problem I address is a knowledge-based model for the design and
development of units of learning and teaching aids. The idea originates from the
analysis of the open issues in instructional authoring system, and from the lack of a
welldefined process able to merge pedagogical strategies with systems for the knowledge
organization of the domain. In particular, the plan is to ground the work on the ECM
Educational Concept Map - model: a logical and abstract annotation system, derived
from the theories of instructional design, developed with the aim of guaranteeing the
reusability of both teaching materials and knowledge structures [
An ECM has a two level structure: the level of concept, i.e. a model of representation of the subject matter where each topic can be associated (level of resources) with one or more resources describing the topic itself (documents, pictures, movies, ...). The plan is therefore to use the level of concept to automatically search relevant resources that are, in turn, associated to each topic of the level of concept in semi automatic way (by approval of the teacher). That is planned to do translating the ECM structure in RDF triples and activating web search extracting data from educational datasets by means of a combination of triples (see research questions). 2
The problems I address in this thesis are still open issues in instructional authoring
system, and there is still a lack of a well-defined process able to merge pedagogical
strategies with systems for the knowledge organization of the domain. By means of
the logical and abstract annotation model of ECMs, it will be possible to design
lessons and/or learning paths (see previous section). Once an ECM for a subject matter is
defined by a teacher, the design of a lesson (for the teacher) and the surfing through a
learning path for a student become a problem of topological sorting (on a graph) [
Indeed, once an ECM is defined, the teacher can design a lesson adapting it on the previous background of its class, and a student can personalize the learning path depending on its specific knowledge and skills. 3
This thesis addresses the problem of instructional authoring system from different
point of view trying to integrate into a same model distinct aspects. From the
pedagogical point of view, the framework of reference is that depicted by Stelzer and
Kingsley in [
The goal of this thesis is to development a system that assist the teacher for the design of a course by proposing a pliable model of domain knowledge on the base of a course (see relevancy) with the aim of guarantee the reusability of both the teaching aids and knowledge structure of a single disciplines. As to reusability, the ECM are designed to maintain the concept layer separate from the resources, making it possible to provide courses with the same CCM from the ECM but with different resources. Furthermore. for the implementation of efficient information search, metadata will be a central component and an pedagogical ontology describing the characteristics of the didactic resource will be defined. In TM metadata can be isolated and stored separately from the object, but still closely connected to the object. Since we need a representation of domain that can be seen from different points of view, each view showing a different structure, different set of parts, differently related [Prietula and Marchak, 1985] it seemed to us that TM are an appropriate abstraction for designing units of learning. Once an educational objective is define the system will assist the design of the course by automatically identifying the “prerequisites”, in other words the concept that a student must know before attending a given unit of learning and the learning outcomes, on base of the relations (see approach). Still in assisting the teacher it remains an open problem how to propose and identify automatically resources to him/her. Accessibility, readability and searchability of web information are crucial for the semi-automatic extension of the knowledge base of our ECM. Integrating information from the two coexisting semantic web exchanging formats (RDF and TM) it’s not a straightforward process, but our idea of web information retrieval is based on simplificate mapping of topics to RDF triples for RDF extraction of data from educational datasets. In order to propose to the teacher a possible sequence of topics where each topic can appear only once and cannot be preceded by any of his successors the systems implements a topological order modified algorithm that provides all the possible sequence of topological sorting (see approach). This is possible since between the units of learning and between the topics there could be a propedeutic relations (isrequirement-of) which is unidirectional relation that impose a precedence relationship that makes the unit of learning an acyclic graph. 5
The availability of “sound” knowledge-based tools increases the productivity of teachers (time and quality) in the daily process of instructional design.
The system is in the initial stage of implementation. The decision on the
implementation framework to use for the development was conditioned on the usage of an open
source framework that implements the TM standard possibly with active community.
One further requirements was the mapping functionality of TM to RDF and vice
versa. At first we focused on testing two open-source tools, Ontopia [
Educational Concept Maps (ECMs) are a formal representation of the subject matter
structure in the context of learning environments, and a formal definition of the model
is available in [
These relation types have been defined with the aim of allowing teachers to create different learning paths (with or without precedence constraints among topics). The same types of relationship can be found between topics. The latter are the smaller granularity of the ECM model. They represent the concepts of the domain: any subjects a teacher may want to talk about. Moreover, the units of learning are connected to the topics through two relationships: o has-primary-topic: where a primary topic identifies the “prerequisites”, in other words the concept that a student must know before attending a given unit of learning; o has-secondary-topic: where secondary topic identifies the concepts that will be explained in the present unit of learning (this kind of topics will have specific learning materials associated).
In the ECM model, a course unit contains an educational objective and a unit of learning. Connected to the UoL there are the topics of the conceptual map describing the domain of the course itself. These topics can be both primary or secondary, depending on the context they are included in, within the unit of learning. Finally the secondary topics contain the material aid. Such resources, grouped in a unit of learning, enable to reach the objective connected to the UoL itself. The CUs allow the teachers to create complex nested structures using the EA.
The ECM model is the theoretical framework for the design of a system, currently in the implementation phase, with some innovative features described in the following: 1. The possibility to publish an Educational Concept Map on the Web and the relationships suggest the different navigation strategies of the underlying subject matter. The possibility to generate a linearized path, useful, for example, for a teacher to produce a lesson or a document about a given subject matter. In this latter case, a Suggested Paths Strategy is necessary, to be expressed by means of is-requirement-of relationships.
To explain the strategy behind the Suggested Paths Strategy, let us also consider the idea of preparing a lesson on a given argument, using the previous ECM model. The Rreq (is-requirement-of) relationships order the topics T of the lesson according to the propaedeutics rules, therefore in the graph G=(T, E) there cannot be loops, thus obtaining a Direct Acyclic Graph (DAG), where T are nodes and E arcs, with: (ti,tj) req(ti, tj).
In this context, a Topological Order is a sequence S = {s1, s2, … s|T|} where each
element T appears only once and cannot be preceded by any of his successors; given
pair of nodes (ti,tj) in S if there exists an arc from ti to tj, it follows that the node ti is
before the node tj in the list: (ti,tj) S: (ti,tj)
The algorithm implementing the Topological Order is derived by Topological sorting
algorithm [
In order to implement such a model, Topic Maps (TM) has been chosen. TM is an
ISO multi-part standard [
Therefore, two layers can be identified into the TMs paradigm: the knowledge layer representing topics and their relationships, allowing to construct the ECM model; the information layer describing information resources, to be attached to the ECM topics.
Each topic can be featured by any number of names (and variants for each name); by any number of occurrences, and by its association role, that is a representation of the involvement of a subject in a relationship represented by an association. All these features are statements and they have a scope representing the context a statement is valid in. Using scopes it is possible to avoid ambiguity about topics; to provide different points of view on the same topic (for example, based on users’ profile) and/or to modify each statement depending on users’ language, etc. Therefore, to solve ambiguity issues, each subject, represented by a topic, is identified by a subject identifier. This unambiguous identification of subjects is also used in TMs to merge topics that, through these identifiers, are known to have the same subject (two topics with the same subject are replaced by a new topic that has the union of the characteristics of the two originals).
The knowledge layer can also be used, as introduced in the Problem Statement section, to automatically search relevant resources that are, in turn, associated to each topic of the information layer in semi automatic way (by approval of the teacher). 8
The system is presently in a first stage of implementation. Particular attention will be paid to the design and implementation of the user interface. There is a plan during the second half of the next year of my PhD course to experiment the prototype of the system within a selected teachers of EPICT community (www.epict.it), a large community of teachers of the Italian secondary schools. The plan is to measure both the usability of the user interface and the instrument's effectiveness in terms of improving the work of the teacher. In particular, it will seek to evaluate the improvement of daily activities of instructional design carried out by the teacher in terms of both the reduction of design time, and of increased efficacy of the process of instructional design.
I will prepare questionnaire to collect quantitative data, deepen then the results with focus groups.
The experience of teachers with this system will be compared with the previous experience of the same teachers 9
The idea behind this thesis has been stimulated by the real “needs” of a community of teachers to have model and tools that facilitates some phases of instructional design. Since the concept representation is independent of its implementation, ECM lends itself for reusability of both teaching materials and knowledge structure. Thus the knowledge structure could be reused for the design of a different course according to the learner target, and new resources could be automatically proposed for the information layer, hence semi-automatically populating (by approval of the teacher) the course map. From student point of view, the subject-centric nature of the TM help learners to identify core concepts, while the extended TM with the learning path assists the student for proper order sequence of studying. Moreover, the underlying model, ECM, is grounded on pedagogical reflections. For these reasons we believe that this model will have a good acceptance by the community of teachers we plan to select for the testing phase.
I would like to express my very great appreciation to my PhD Advisor Prof. Giovanni Adorni, acknowledging his valuable ideas, constructive suggestions and support during the planning and development of the ECM model and this research work.