Search

In intelligent e-learning systems that adapt a learning and teaching process to student knowledge, it is important to adapt the system as quickly as possible. However, adaptation is not possible until the student model is initialized. In this paper, a new approach to student model initialization using domain knowledge representative subset is described. The approach defines which concepts from domain knowledge should be included in the initial test so the system can make conclusions about what students truly know about domain knowledge. This representative subset of domain knowledge is defined using non-semantic mathematical approach based on graph theory. The initial test, created over a domain knowledge representative subset, guarantees encompassing all concepts that are relevant to domain knowledge. A two-level case study is conducted on what would be the representative subset of one selected domain knowledge. It compares semantically selected domain knowledge representative subsets (semantical analysis was done by domain area experts) to a non-semantical, mathematically selected domain knowledge representative subset. The results of the case study show that problems of inequality of semantically selected domain knowledge representative subsets are easily overcome using the presented approach.

Various approaches to text simplification have been proposed in an attempt to increase text readability. The rephrasing of syntactically and semantically complex structures is still challenging. A pedagogically motivated simplified version of the same text can have both positive and negative side effects. On the one hand, it can facilitate reading comprehension because of much shorter sentences and a limited vocabulary, but on the other hand, the simplified text often lacks coherence, unity and style. Therefore, reasonable trade-offs among linguistic simplicity, naturalness and informativeness are highly needed. This is a survey paper that discusses state-of-the-art approaches to sentence/text simplification and evaluation methods, along with an empirical evaluation of our approach. The quality of sentence splitting, using the knowledge extraction tool SAAT was compared to state-of-the-art syntactic simplification systems. The research was carried out on the WikiSplit, the HSplit and MinWikiSplit simplification corpora. Automatic metrics for the HSplit showed that the SAAT outperformed other TS systems in all categories. For the WikiSplit dataset, automatic metrics scores were slightly lower than that of the baseline system DisSim. However, the human evaluation showed that DisSim outperformed the SAAT in terms of simplicity and grammar. The quality of AG18copy output corresponded to that of the SAAT. The inter-annotator agreement was calculated. Research limitations as well as suggestions for future research were also provided.

In this article we present an knowledge extraction approach that can be used in systems that implement teaching in a fully automated manner. These systems are called Intelligent Tutoring Systems (ITS) and are conceived around the idea of one-to-one teaching. Many such systems use natural language processing to improve the communication interface between student and the system. These techniques can be also used on the content creator side to semi- automate or fully automate the task of teaching content creation. In such systems the knowledge representation plays a crucial role to successfully implement teaching and encourage learning. The output of the knowledge extraction phase is a knowledge in the form of a hyper graph that can be used for adaption to the students current knowledge level. We present a deep neural network architecture for precise POS tagging of words written in languages that are morphologically rich. Using sparse representations for words in this task increases the vector space and makes learning more complex. This problem can be solved to some extent by using traditional vector representations but there is also the problem with representing words that are ambiguous. Proposed architecture uses a Bidirectional Encoder Representations from Transformers (BERT) model that is pre-trained on Croatian language to achieve state-of-the-art accuracy for POS tagging.

The idea of clustering students according to their online learning behavior has the potential of providing more adaptive scaffolding by the intelligent tutoring system itself or by a human teacher. With the aim of identifying student groups who would benefit from the same intervention in AC-ware Tutor, this research examined online learning behavior using 8 tracking variables: the total number of content pages seen in the learning process; the total number of concepts; the total online score; the total time spent online; the total number of logins; the stereotype after the initial test, the final stereotype, and the mean stereotype variability. The previous measures were used in a four-step analysis that consisted of data preprocessing, dimensionality reduction, the clustering, and the analysis of a posttest performance on a content proficiency exam. The results were also used to construct the decision tree in order to get a human-readable description of student clusters.

The reasoning process about the level of student’s knowledge can be challenging even for experienced human tutors. The Bayesian networks are a formalism for reasoning under uncertainty, which has been successfully used for various artificial intelligence applications, including student modeling. While Bayesian networks are a highly flexible graphical and probabilistic modeling framework, its main challenges are related to the structural design and the definition of “a priori” and conditional probabilities. Since the AC&NL Tutor’s authoring tool automatically generates tutoring elements of different linguistic complexity, the generated sentences and questions fall into three difficulty levels. Based on these levels, the probability- based Bayesian student model is proposed for mastery-based learning in intelligent tutoring system. The Bayesian network structure is defined by generated questions related to the node representing knowledge in a sentence. Also, there are relations between inverse questions at the same difficulty level. After the structure is defined, the process of assigning “a priori” and conditional probabilities is automated using several heuristic expert-based rules.

Automatic knowledge acquisition is a rather complex and challenging task. This paper focuses on the description and evaluation of a semi-automatic authoring tool (SAAT) that has been developed as a part of the Adaptive Courseware based on Natural Language AC&NL Tutor project. The SAAT analyzes a natural language text and, as a result of the declarative knowledge extraction process, it generates domain knowledge that is presented in a form of natural language sentences, questions and domain knowledge graphs. Generated domain knowledge presents expert knowledge in the intelligent tutoring system Tutomat. The natural language processing techniques are applied and the tool’s functionalities are thoroughly explained. This tool is, to our knowledge, the only one that enables natural language question and sentence generation of different levels of complexity. Using an unstructured and unprocessed Wikipedia text in computer science, evaluation of domain knowledge extraction algorithm, i.e. the correctness of extraction outcomes and the effectiveness of extraction methods, was performed. The SAAT outputs were compared with the gold standard, manually developed by two experts. The results showed that 68.7% of detected errors referred to the performance of the integrated linguistic resources, such as CoreNLP, Senna, WordNet, whereas 31.3% of errors referred to the proposed extraction algorithms.

Over the last few decades, researchers put efforts to improve intelligent tutoring systems' abilities with the aim to get them as close as possible to the ultimate goal of one-to-one tutoring. CoLaB Tutor and AC-ware Tutor are intelligent tutoring systems based on conceptual knowledge learning and are notable due to the fact they are relatively easy to generalize to multiple knowledge domains. CoLaB Tutor's forte lies in teacher-learner communication in controlled natural language, while AC-ware Tutor focuses on the automatic and dynamic generation of adaptive courseware. In order to compare various intelligent tutoring system supported education environments, in this chapter, the authors summarize several empirical evaluations of CoLaB Tutor and AC-ware Tutor. The results of intelligent tutoring systems' effectiveness in these environments offer the possibility to observe the specific intelligent tutoring system across various education levels, as well as to compare the intelligent tutoring systems' supported education environments.

Probabilistic student model based on Bayesian network enables making conclusions about the state of student’s knowledge and further learning and teaching process depends on these conclusions. To implement the Bayesian network into a student model, it is necessary to determine “a priori” probability of the root nodes, as well as, the conditional probabilities of all other nodes. In our approach, we enable non-empirical mathematical determination of conditional probabilities, while “a priory” probabilities are empirically determined based on the knowledge test results. The concepts that are believed to have been learned or not learned represent the evidence. Based on the evidence, it is concluded which concepts need to be re-learned, and which not. The study described in this paper has examined 15 ontologically based Bayesian student models. In each model, special attention has been devoted to defining “a priori” probabilities, conditional probabilities and the way the evidences are set in order to test the successfulness of student knowledge prediction. Finally, the obtained results are analyzed and the guidelines for ontology based Bayesian student model design are presented.

Purpose– In order to initialize a student model in intelligent tutoring systems, some form of initial knowledge test should be given to a student. Since the authors cannot include all domain knowledge in that initial test, a domain knowledge subset should be selected. The paper aims to discuss this issue.Design/methodology/approach– In order to generate a knowledge sample that represents truly a certain domain knowledge, the authors can use sampling algorithms. In this paper, the authors present five sampling algorithms (Random Walk, Metropolis-Hastings Random Walk, Forest Fire, Snowball and Represent algorithm) and investigate which structural properties of the domain knowledge sample are preserved after sampling process is conducted.Findings– The samples that the authors got using these algorithms are compared and the authors have compared their cumulative node degree distributions, clustering coefficients and the length of the shortest paths in a sampled graph in order to find the best one.Originality/value– This approach is original as the authors could not find any similar work that uses graph sampling methods for student modeling.

As the acquisition of knowledge is often an expensive and time-consuming process, it is important to know whether it actually improves the student performance. The e-learning is a revolutionary paradigm that has lately been significantly evolving and it is closely related to the intelligent tutoring systems. Methodology for evaluating the educational influence of learning and teaching process, questions whether and in what amount, students learn effectively. Our contribution to this compulsive field of research is a meta-analysis of a series of experiments based on the same two-group methodology that reveals a more precise effect size of one particular e-learning system - eXtended Tutor-Expert System, a representative of web-based authoring shells for building intelligent tutoring systems.

Intelligent tutoring systems are kind of asynchronous e-learning systems designed to support and improve learning and teaching process in particular domain knowledge. An authoring shells are kind of e-learning systems that feature authoring environments for system users. Domain knowledge in such systems can be represented by using different knowledge representation specifications and presentation of tests mainly depends on the type of domain knowledge. We propose templates for dynamical generation of questions as a test over previously formalized domain knowledge. In our approach we encourage expressiveness of ontology for describing domain knowledge. Tests described in this paper entails declarative knowledge formalized by Web Ontology Language (OWL) and are realized as a dynamic quiz. By pronouncing OWL ontology as domain knowledge formalism we deal with the problem of generating tests and understanding presentation of the tests.

We believe that every effectiveness evaluation should be replicated at least in order to verify the original results and to indicate evaluated e-learning system’ s advantages or disadvantages. This paper presents the methodology for conducting controlled experiment replication, as well as, results of a controlled experiment and an internal replication that investigated the effectiveness of intelligent authoring shell eXtended Tutor– Expert System (xTEx-Sys). The initial and the replicated experiment were based on our approach that combines classical two-group experimental design and with factoral design. A trait that distinguishes this approach from others is the existence of arbitrary number of checkpoint-tests to determine the effectiveness in intermediate states. We call it a pre-and-post test control group experimental design with checkpoint-tests. The gained results revealed small or even negative effect sizes, which could be explained by the fact that the xTEx-Sys’ s domain knowledge presentation is rather novel for students and therefore difficult to grasp and apply in earlier phases of the experiment. In order to develop and improve the xTEx-Sys, further experiments must be conducted.