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 Educational Concept Maps - a logical and abstract annotation system derived from the theories of instructional design. Our work is motivated by 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 impetus for PhD thesis starts from this awareness. The final goal is the definition of a knowledge-based model and the implementation of a software tool for instructional design with specific focus on the educational content designe, to be used in e-learning environments. Our model takes into account the perspectives of development that appear to promise the web today, and is grounded on pedagogical reflection and scientific knowledge we have today.
This thesis addresses the problem of instructional authoring system from different
points of view trying to integrate them into a same model. From the pedagogical point
of view, the framework of reference is that presented by Stelzer and Kingsley in
"Theory of Subject Matter Structure"[
The paper is organized as follows. After the next preliminary section introducing the problem, in Sect. 3 the details about our approach and model will be illuminated, in Sect. 4 we pass from the model to its implementation. Sect. 5 shows the relevancy. The Hypotheses and the preliminary results are found in Sect. 6. Finally the evaluation plan and reflection are given in Sect. 7 and Sect. 8. 2
The approach proposed in this thesis finds its foundation in the work of those who have addressed the problems underlying the processes of learning and knowledge representation, with particular attention to the semantic web research area.
The idea originates from the analysis of the open issues in instructional authoring
systems, and from the lack of a well-defined 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 [
The ECM is implemented by means of semantic web standards and technologies
[
The goal of this thesis is to develop a system that assists the teacher for the design
of a course curricula by proposing a pliable model of domain knowledge on the base
of a course with the aim of guaranteeing the reusability of both the teaching aids and
knowledge structure of a single disciplines. The knowledge structure could be: the
general one, representing the knowledge domain i.e. the ECM, or a CCM (Course
Concept Map), representing the specific user vision of the domain, e.g., specific
teacher vision of a subset of the course domain. As to reusability, the ECMs 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.
Since we need a representation of the domain that can be seen from different points of
view, each view showing a different structure, different set of parts, differently
related [
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 [
According to that model, a profiled learner has a goal identified by an objective (or a composition of objectives) that is achieved by a UoL, or by a composition of UoLs. The Course Unit (CU) is the indivisible union of an objective with its unit of learning and can be composed by creating the tree structure of the course (learning units, sublearning units, etc.). The course units may be connected each other by means of the Educational Associations (EA) that may represent a link or a propaedeutic relationship the units have (see Fig. 1.). In particular, four types of EA have been identified: • is-requirement-of: denoted as Rreq, identifying a transitive and propaedeutic association between two or more topics, e.g. it may be used with the aim of specifying the logical order of contents; • is-item-of: denoted as Rit, identifying a hierarchical asymmetric association among two topics in order to denote a specific relationship of an individual topic and its more general topic, or a membership relationship; • is-related-to: denoted as Rrel, identifying a symmetric association among closely related topics (e.g., it may be used with the aim of creating learning paths without precedence constraints); • is-suggested-link-of: denoted as Rsug, identifying an asymmetric association among a topic and it's in-depth examination, e.g. this relationship type may be used in order to suggest in-depth resources.
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 UoL are connected to the topics through two relationships: • has-primary-topic: where a primary topic PT identifies the “prerequisites” of a CCM, in other words the concept that a student must know before attending a given unit of learning; • has-secondary-topic: where secondary topic ST identifies the concepts that will be explained in the present unit of learning (this kind of topics will have specific learning materials associated). 4
The ECM model is the theoretical framework for the design of our so called ENCODE – ENvironment for COntent Design and Editing application, currently in the implementation phase, with some innovative features described in the following: 1. 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. 2. The possibility to publish a CCM on the Web and the relationships suggest the different navigation strategies of the underlying subject matter.
To explain the strategy behind the Suggested Paths Strategy, let us also consider the idea of preparing a lesson on a given subject matter, 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) ∈ E ↔ Rreq(ti, tj). In this context, a Topological Order on a CCM is a sequence S = {s1, s2, … s|T|} where each element T appears only once and cannot be preceded by any of its successors; given pair of nodes (ti,tj) in S if there exists an arc from ti to tj of type is-requirement-of, it follows that the node ti is before the node tj in the list: ∀(ti,tj) ∈ S: (ti,tj) ∈ E → i < j.
The algorithm implementing the Topological Order is derived by Topological
sorting algorithm [
Furthermore, for better presentation of the knowledge structure and effective navigation a cluster with a name Nc is defined, by grouping all the topics ti that are in a isitem-of relationship, i.e. Rit(ti, tj) with a common topic tj. More formally we define a cluster C={Nc, Tc} as a non-empty finite set of topics Tc, where ∀ti∈ Tc and ∃tj∉ Tc where Rit(ti, tj).
For as much as the topics are topologically ordered this doesn’t take into account
the distance factor in between the topics, thus a signaling (denoted as Topic Aider
TA) is introduced in the sequence S before the distant topic to remind its subject. The
TA is a suggestion for the teacher to introduce an exercise, an example, a text or a
valuation test. This TA is also reported in the final sequence in order to highlight not
only to the teacher, but also to the student the place where s/he should evoke a
determinate argument. The choice to have not a single path but a list of paths to suggest to
the author leaving the final choice to the author him/herself, is also to answer to the
non-equifinality problem posed in [
In order to implement such a model, TM has been chosen. TM is an ISO multi-part
standard [
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).
ENCODE application is designed in a layered manner aiming at reducing
complexity and improving extensibility. The implementation of the application is based on
extending and reusing already available modules, i.e. from the wandora engine [
ENCODE user interface allows a user to build/import/export/visualize domain/course knowledge. The main end user is the Teacher that uses the tool as a Map Designer; Resource Creator or Corse Consumer. The Corse Consumer benefits from the tool by using the linear path of the CCM imported in the Semantically Structured TextEditor as an educational material to use it at school; by using the html format of the CCM to publicate the course materials; importing the XTM format of the structure of the course in an LCMS (i.e., moodle). Other end users are the authors of books or research papers, and in the end the students for explorative studying and/or for the design of concept maps. Thus, ENCODE User Interface layer includes: Editor that import ECM/CCM in XTM format; exports ECM/CCM in a XTM format; generates ECM/CCM web pages for a web view navigation of the knowledge i.e. ECM/CCM Navigation; uploads ECM/CCM to the ECM/CCM web Repository; imports the linearized ECM/CCM in an semantically structured text editor for further editing. Having a user-friendly interface and a graph representation of the subject matter is the main requisite for this layer.
The Logical Layer handles the user's actions and in order to maintain the
consistency in the ECM/CCM, performs consistency checks and reasoning for the TAO
(Topic Association Occurrence) operation. The consistency checks can be of a
syntactic and semantic nature. A schema is needed that contains all the information
necessary for the validation process, i.e. the ECM is validated against a template ECM
Schema. The ECM Schema is defined by TMCL (Topic Maps Constraint Language)
[
User User Interface layer
ECM/CCM Editor Logical layer
Consistency Checker Functional layer
Local Access
Remote
Access Physical layer
In-memory
ECM/CCM Navigation webview
ECM/CCM Web Repository
Semantically Structured TextEditor TAO Manager
Topological Ordering Merging of ECM//CCM
Search in ECM/CCM
XTM
However, a number of CTM templates are defined in this International Standard in order to facilitate authoring of TMCL schemas using CTM(Compact Topic Maps syntax). Thus a ECM.ctm was defined. The ECM.ctm restricts the Topic Map model to education topic type; four education association types specifying the relation properties (symmetric, transitive, asymmetric) and the education role types involved. TMCL is firmly meant for validation, and not for reasoning. Consistency check are made for:
- detecting unreachable topic ti ∈ CCM: i.e. ti is unreachable if ti ∉ PT and for ∀Rreq(*,ti) ∄path(tpt,*) where tpt ∈ PT. Formally a path(ti,tj) among two topics ti and tj is defined by a direct relation Rreq(ti,tj) in case of adiacent topics (in this case the "length" of a path is 0), or by the recursive definition Rreq(ti,tu)Λ path(tu,tv)Λ Rreq(tv,tj) in case of not adjacent topics (in this case the "length" of a path is define by the number of topics between ti, and ti). It's worth nothing that between two generic topics ti and tj more than one path can exist.
- On adding a is_requirement_of association Rreq(ti,tj) where ti,tj ∈ ECM or ti,tj ∈ CCM, loop verification is needed starting from topic ti, where a loop is formally defined as path(ti, ti) with "length" > 0;
- The deletion of a topic ti demands deletion of all the associations in which the topic ti is involved. After deletion a check on possibly unreachable topics is needed. If there is a path of "length" 1 , i.e., Rreq(tu,tv) Λ Rreq(tv,tk) than on deletion of the tv a Rreq(tu,tk) is created.
- The topic tj that is an in-depth examination of some other topic it can't have exiting arcs, i.e. for ∀Rsug(ti,tj) ∄R(tj, *) where R∈{Rsug, Rin, Rreq, Rrel}.
- There can be only one relation between two topics, i.e. for every ti,tj∈ ETM or ti,tj ∈ CCM ∃! R(ti, tj) where R∈{Rsug, Rin, Rreq, Rrel}.
Reasoning is adopted in order to keep the CCM consistent from the propaedeutic point of view. During the CCM creation, after user chooses the desired topics, ENCODE fills up the CCM recursively with the missing preparatory topics starting from the added topics, i.e. if ∃Rreq(ti,tj) where ti, tj ∈ ETM and tj ∈ CCM, than ENCODE adds ti to the CCM.
The Functional Layer modules directly interact with the logical representation of the knowledge in order to save the project locally; upload it to the server repository; merge of ECM/CCM; visualize and adds associations to the concept map graph.
The Physical Layer represents the backend of ENCODE, where the knowledge base is saved: during editing in-memory; permanently as XTM files locally or remotely; or in a non thread-safe RDBMS. 5
The problems faced in this thesis are still open issues in instructional authoring
systems, since there is 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 navigating
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. 6
It's hypothesized that the availability of “sound” knowledge-based tools will increase the productivity of teachers (time and quality) in the daily process of instructional design.
This being said 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 and an open source text editor. At first we focused on testing two
open-source tools, Ontopia [
During the implementation of the system 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 group of teachers of the 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. 8
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. 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, guidance and support during the planning and development of the ECM model and this research work. I am also particularly grateful to my paper supervisors, Prof.Dr. Judy Goldsmith and Dr. Nick Mattei, for all the useful and constructive suggestions.