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- Cristóbal Romero, Sebastián Ventura, Paul De Bra, Carlos de Castro
- User Modeling
- 2003

In this paper we are going to show how to discover interesting prediction rules in student usage information, and use them to improve adaptive web courses. We have used AHA! to make a course that adapts both the presentation and the navigation depending on the level of knowledge that each particular student has. We have made several changes in AHA! to… (More)

- Carlos de Castro, M. Pavšič
- 2004

An introduction to some of the most important features of the Extended Relativity theory in Clifford-spaces (C-spaces) is presented whose ”point” coordinates are non-commuting Clifford-valued quantities which incorporate lines, areas, volumes, hyper-volumes.... degrees of freedom associated with the collective particle, string, membrane, p-brane,...… (More)

- Enrique García, Cristóbal Romero, Sebastián Ventura, Carlos de Castro
- User Modeling and User-Adapted Interaction
- 2008

Nowadays we find more and more applications for data mining techniques in e-learning and web-based adaptive educational systems. The useful information discovered can be used directly by the teacher or author of the course in order to improve instructional/learning performance. This can, however, imply a lot of work for the teacher who can greatly benefit… (More)

In this paper we show how to apply genetic algorithms for data mining of student information obtained in a Web-based Educational Adaptive Hypermedia System. The objective is to obtain interesting association rules so that the teacher can improve the performance of the system. In order to check the proposed algorithm we have used a Web-based Course developed… (More)

In this paper we show how the AHA! system was (modified and) used to create an adaptive course in which the course material is presented in three levels of difficulty. The aim of the experiment is to perform data mining in order to find good candidates for meaningful relations between reading times, difficulty levels and test results. We want to discover… (More)

- Carlos de Castro
- 2002

An outline is presented of the Extended Scale Relativity (ESR) in C-spaces (Clifford manifolds), where the speed of light and the minimum Planck scale are the two universal invariants. This represents in a sense an extension of the theory developed by L.Nottale long ago. It is shown how all the dimensions of a C-space can be treated on equal footing by… (More)

- Carlos de Castro
- 2008

Born’s reciprocal relativity in flat spacetimes is based on the principle of a maximal speed limit (speed of light) and a maximal proper force (which is also compatible with a maximal and minimal length duality) and where coordinates and momenta are unified on a single footing. We extend Born’s theory to the case of curved spacetimes and construct a… (More)

- Carlos de Castro
- 2007

A novel Chern-Simons E8 gauge theory of Gravity in D = 15 based on an octic E8 invariant expression in D = 16 (recently constructed by Cederwall and Palmkvist) is developed. A grand unification model of gravity with the other forces is very plausible within the framework of a supersymmetric extension (to incorporate spacetime fermions) of this Chern-Simons… (More)

- Carlos de Castro
- 2007

The large N → ∞ limit of the Exceptional F4, E6 Jordan Matrix Models of Smolin-Ohwashi leads to novel Chern-Simons Membrane Lagrangians which are suitable candidates for a nonperturbative bosonic formulation of M Theory in D = 27 real, complex dimensions, respectively. Freudenthal algebras and triple Freudenthal products permits the construction of a novel… (More)

- Carlos de Castro
- 2008

We argue why the static spherically symmetric (SSS) vacuum solutions of Einstein’s equations described by the textbook Hilbert metric gμν(r) is not diffeomorphic to the metric gμν(|r|) corresponding to the gravitational field of a point mass delta function source at r = 0. By choosing a judicious radial function R(r) = r + 2G|M |Θ(r) involving the Heaviside… (More)