tem using Netflix database. MF algorithm decom-
poses the rating matrix into user and item latent matri-
ces. The re-decomposed matrix can be used for find-
ing the votes for the unknown items for every user.
Cross-validation methodology was applied, for tun-
ing λ, which is a parameter used during the MF op-
timization and helps the system avoiding over-fitting.
Furthermore, authors tried to address items and user
progress over time by making use of temporal dynam-
ics and applying user and item biases deviations to the
re-decomposition of the rating matrix. The proposed
system won the 2007 and 2008 Progress Prize of Net-
flix challenge.
In (Salakhutdinov and Mnih, 2011), authors pro-
posed a probabilistic matrix factorization (PMF), for
decomposing the rating matrix of users-items using
the Neflix database. A probabilistic way to tune the
regularization parameter λ for the matrix decomposi-
tion was proposed. Finally, they combined the PMF
model with Restricted Boltzmann Machines models
in order to improve the performance of the system.
Their approach was proved to perform well on very
sparse and imbalanced datasets and in handling the
over-fitting problem of the optimization as well.
In (Milicevic et al., 2011), authors proposed a pro-
gramming tutoring system called “Protus”, developed
for teaching Java programming language. The main
scope of “Protus” is to recommend the best possible
material for the e-learners based on their background
and skills. The proposed system consists of three ba-
sic modules. When learners were registered to the
system, a short survey was performed with aim to re-
flect their preferred learning style. Then, a cluster-
ing technique is applied in order to create clusters of
learners based on their learning style. Finally Aprio-
riAll algorithm (Tong and Pi-lian, 2007) was used to
find frequent sequences of learning materials patterns
in each learning style and make the recommendation
accordingly. These generate recommendations based
on the collaborative filtering approach.
In (Segal et al., 2014), authors proposed “Edu-
Rank”, a system for personalizing educational con-
tent for learners, which combines collaborative filter-
ing and social choice theory. The algorithm constructs
a difficulty ranking over questions and aggregates the
ranking of similar students, as measured by different
aspects of their performance on past questions such
as grades, number of retries and time spent solving
questions. Thus, the first step of the algorithm is to
estimate the similarity of learners and then, combine
the rankings of the similar users to propose it to the
target user.
In (Bachari et al., 2011), authors presented three
main models to achieve the goal of personalization,
which are domain model, tutor model, and student
model. The domain model contains the knowledge
about the learning content structure such as chapters
and topics of different subjects while student model
holds the learners characteristic including their pref-
erences, identity. These can be used to adapt the con-
tent and teaching styles. This research has added
tutor model to enhance the personalization system
from the previous research. The tutor model repre-
sents the teacher’s knowledge for teaching each con-
cept. The decision and identification model used in
this work was based on Dynamic Bayesian Network
(DBN). DBNs were used with a goal to introduce to
the learner the contents and materials of interested in
according to the score obtained by the learner using
the Myers-Briggs Type Indicator (MBTI) test.
In (Bergner et al., 2012), authors proposed a
model-based estimator of accuracy levels of learn-
ers performance and skill levels on real and simu-
lated datasets. Furthermore, they established a rela-
tionship between collaborative filtering and Item Re-
sponse Theory methods and demonstrated this rela-
tionship empirically.
In (Toscher and Jahrer, 2009), authors make use of
KDD Cup 2010, an educational database (J.Stamper
et al., 2010) which contains questions from algebra
topic in several steps and difficulty and the learner
performance as well (answer, time spent etc.). Au-
thors implemented several methods to model the
database. Firstly, they applied K-Nearest Neigh-
bors in order to find the most similar users. Au-
thors also implemented Singular Value Decomposi-
tion (SVD) in order to decompose the matrix of users
and questions-steps using stochastic gradient descent.
Authors found out that SVD does not work well with
sparse data so they proposed an enhanced algorithm,
called Factor Model (FM) in which they add bias
models (as in (Y. Koren and Volinsky, 2009)) in the
re-decomposition of the user-steps matrix. Finally, a
Neural Network architecture called Restricted Boltz-
mann Machines was applied to ensemble the men-
tioned models.
In (Liao, 2006), a study of flow theory in human
computer interaction was performed. This study con-
sists of two main models: Firstly, an empirical inves-
tigation of the theoretical construct of flow theory in
Computer-based Education which tried to identify the
main components of flow during the learning process
and, secondly, a study of the impact of interaction be-
tween three different categories of flow. Those cate-
gories were: learner to instructor interactions, learner-
learner interactions and finally learner-interface inter-
actions.
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